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Sample records for small forest lakes

  1. Forest blowdown and lake acidification

    International Nuclear Information System (INIS)

    Dobson, J.E.; Rush, R.M.; Peplies, R.W.

    1990-01-01

    The authors examine the role of forest blowdown in lake acidification. The approach combines geographic information systems (GIS) and digital remote sensing with traditional field methods. The methods of analysis consist of direct observation, interpretation of satellite imagery and aerial photographs, and statistical comparison of two geographical distributions-one representing forest blow-down and another representing lake chemistry. Spatial and temporal associations between surface water pH and landscape disturbance are strong and consistent in the Adirondack Mountains of New York. In 43 Adirondack Mountain watersheds, lake pH is associated with the percentage of the watershed area blown down and with hydrogen ion deposition (Spearman rank correlation coefficients of -0.67 and -0.73, respectively). Evidence of a temporal association is found at Big Moose Lake and Jerseyfield Lake in New York and the Lygners Vider Plateau of Sweden. They conclude that forest blowdown facilities the acidification of some lakes by altering hydrologic pathways so that waters (previously acidified by acid deposition and/or other sources) do not experience the neutralization normally available through contact with subsurface soils and bedrock. Increased pipeflow is suggested as a mechanism that may link the biogeochemical impacts of forest blowdown to lake chemistry

  2. Water quality and fish dynamics in forested wetlands associated with an oxbow lake

    Science.gov (United States)

    Andrews, Caroline S.; Miranda, Leandro E.; Kroger, Robert

    2015-01-01

    Forested wetlands represent some of the most distinct environments in the Lower Mississippi Alluvial Valley. Depending on season, water in forested wetlands can be warm, stagnant, and oxygen-depleted, yet may support high fish diversity. Fish assemblages in forested wetlands are not well studied because of difficulties in sampling heavily structured environments. During the April–July period, we surveyed and compared the water quality and assemblages of small fish in a margin wetland (forested fringe along a lake shore), contiguous wetland (forested wetland adjacent to a lake), and the open water of an oxbow lake. Dissolved-oxygen levels measured hourly 0.5 m below the surface were higher in the open water than in either of the forested wetlands. Despite reduced water quality, fish-species richness and catch rates estimated with light traps were greater in the forested wetlands than in the open water. The forested wetlands supported large numbers of fish and unique fish assemblages that included some rare species, likely because of their structural complexity. Programs developed to refine agricultural practices, preserve riparian zones, and restore lakes should include guidance to protect and reestablish forested wetlands.

  3. Net heterotrophy in small Danish lakes: A widespread feature over gradients in trophic status and land cover

    DEFF Research Database (Denmark)

    Sand-Jensen, Kaj; Stæhr, Peter Anton

    2009-01-01

    Nineteen small lakes located in open landscapes or deciduous forests in nutrient-rich calcareous moraines in North Zealand, Denmark, were all net heterotrophic having negative net ecosystem production and predominant CO2 supersaturation and O2 undersaturation of lake waters. Forest lakes were...... poorer in nutrients, phytoplankton, and primary production, but richer in dissolved organic matter and CO2 than open lakes with more light available. The modeled annual balance between gross primary production and community respiration (GPP/R COM) averaged 0.60 in forest lakes and 0.76 in open lakes...... and the ratio increased significantly with phosphorus concentration and phytoplankton biomass but decreased with colored dissolved organic matter. The negative daily rates of ecosystem production resembled estimates of oxygen uptake from the atmosphere to the lakes, whereas estimates of CO2 emission were 7...

  4. 77 FR 18997 - Rim Lakes Forest Restoration Project; Apache-Sitgreavese National Forest, Black Mesa Ranger...

    Science.gov (United States)

    2012-03-29

    ... DEPARTMENT OF AGRICULTURE Forest Service Rim Lakes Forest Restoration Project; Apache-Sitgreavese National Forest, Black Mesa Ranger District, Coconino County, AZ AGENCY: Forest Service, USDA. ACTION: Notice of intent to prepare an environmental impact statement. SUMMARY: The U.S. Forest Service (FS) will...

  5. Multi-trophic resilience of boreal lake ecosystems to forest fires.

    Science.gov (United States)

    Lewis, Tyler L; Lindberg, Mark S; Schmutz, Joel A; Bertram, Mark R

    2014-05-01

    Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll a levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

  6. The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

    Directory of Open Access Journals (Sweden)

    S. A. Watmough

    2002-01-01

    Full Text Available The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario. In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1 from

  7. Grow--a computer subroutine that projects the growth of trees in the Lake States' forests.

    Science.gov (United States)

    Gary J. Brand

    1981-01-01

    A computer subroutine, Grow, has been written in 1977 Standard FORTRAN to implement a distance-independent, individual tree growth model for Lake States' forests. Grow is a small and easy-to-use version of the growth model. All the user has to do is write a calling program to read initial conditions, call Grow, and summarize the results.

  8. Waxing and Waning of Forests: Late Quaternary Biogeography of Lake Malawi, Southeast Africa

    Science.gov (United States)

    Ivory, S.; Lézine, A. M.; Vincens, A.; Cohen, A. S.

    2014-12-01

    African ecosystems are at great risk due to climate and land-use change. Despite the status of several of these regions as biodiversity hotspots, long-standing ideas about African ecology and biogeography have been unable to be tested until now due to lack of sufficiently long records. Here, we present the first long, continuous terrestrial record of vegetation from Lake Malawi, East Africa which goes back to the early Late Quaternary, permitting us to investigate changes in physiognomy and forest composition over many transitions. In this record, we observe eight phases of forest expansion and collapse. Although diversity is much greater during forest phases, composition varies little from phase to phase. Very high abundances of afromontane taxa suggest frequent widespread colonization of the lowlands by modern high elevation trees. Although there are clear successional stages within each forest such that turnover is great within a single phase, among forest samples between phases, there is little dissimilarity. Each forest phase is interrupted by rapid decline of arboreal taxa and expansion of semi-arid grasslands or woodlands whose composition varies greatly from phase to phase. The variable composition of the more open phases, all occurring during arid periods, is likely dynamically linked to thresholds in regional hydrology associated with lake level and moisture recycling within the watershed. This vegetation is unlike any found at Malawi today, with assemblages suggesting strong Somali-Masai affinities. Furthermore, nearly all semi-arid assemblages contain small abundances of forest taxa typically growing in areas with wetter edaphic conditions, suggesting that moist lowland gallery forests were present but restricted to waterways during exceptionally arid times. The waxing and waning of forests throughout this interval has important implications for early human biogeography across Africa as well as disturbance regimes that are crucial for the maintenance of

  9. Analysis of long-term forest bird monitoring data from national forests of the western Great Lakes Region

    Science.gov (United States)

    Gerald J. Niemi; Robert W. Howe; Brian R. Sturtevant; Linda R. Parker; Alexis R. Grinde; Nicholas P. Danz; Mark D. Nelson; Edmund J. Zlonis; Nicholas G. Walton; Erin E. Gnass Giese; Sue M. Lietz

    2016-01-01

    Breeding bird communities in forests of the western Great Lakes region are among the most diverse in North America, but the forest environment in this region has changed dramatically during the past 150 years. To address concerns about loss of biodiversity due to ongoing forest harvesting and to better inform forest planning, researchers have systematically monitored...

  10. Pequonnock River Basin, Bridgeport, Connecticut. Forest Lake Dam CT 00078. Phase I Inspection Report. National Dam Inspection Program.

    Science.gov (United States)

    1978-08-01

    Legislation for the protection of wet lands has come too late for this watershed and the remaining small wet lands, if retained, have little value...Ridge Mountains of Central Virginia, 11.55" in Westminister , Maryland and 13" in Steuben County, Pennsylvania. HYDRAULIC ANALYSIS LAKE FOREST Due to

  11. Special Forest Products on the Green Mountain and Finger Lakes National Forests: a research-based approach to management

    Science.gov (United States)

    Marla R. Emery; Clare. Ginger

    2014-01-01

    Special forest products (SFPs) are gathered from more than 200 vascular and fungal species on the Green Mountain National Forest (GMNF) and Finger Lakes National Forest (FLNF). This report documents those SFPs and proposes an approach to managing them in the context of legislation directing the U.S. Forest Service to institute a program of active SFP management. Based...

  12. The importance of bacterial utilization of released phytoplankton photosynthate in two humic forest lakes in southern Finland

    International Nuclear Information System (INIS)

    Jones, R.I.; Salonen, K.

    1985-01-01

    Bacterial utilization of photosynthetically fixed dissolved organic carbon (PDOC) released from natural phytoplankton assemblages was studied in two small, extremely humic, forest lakes in southern Finland. Bacterial activity (measured us uptake of 14 C-glucose) and phytoplankton photosynthesis (measured as light uptake of 14 CO 2 ) could be most effectively separated using Nuclepore filters of pore 1-2 μm. Released PDOC was 10-67% of total phytoplankton carbon fixation during in situ experiments, and represented about 0.1% of total DOC. Net uptake of PDOC by bacteria was found to be about 20% during 24 hour laboratory incubations, although about 40% of PDOC present at the start of an experiment could be utilized by bacteria during a 24 hour period. PDOC does not provide a quantitatively important substrate supply fo bacterial respiration in humic forest lakes. (author)

  13. Effects of Lakes on Wildfire Activity in the Boreal Forests of Saskatchewan, Canada

    Directory of Open Access Journals (Sweden)

    Scott E. Nielsen

    2016-11-01

    Full Text Available Large lakes can act as firebreaks resulting in distinct patterns in the forest mosaic. Although this is well acknowledged, much less is known about how wildfire is affected by different landscape measures of water and their interactions. Here we examine how these factors relate to historic patterns of wildfire over a 35-year period (1980–2014 for the boreal forest of Saskatchewan, Canada. This includes the amount of water in different-sized neighborhoods, the presence of islands, and the direction, distance, and shape of nearest lake of different sizes. All individual factors affected wildfire presence, with lake sizes ≥5000 ha and amount of water within a 1000-ha surrounding area the most supported spatial scales. Overall, wildfires were two-times less likely on islands, more likely further from lakes that were circular in shape, and in areas with less surrounding water. Interactive effects were common, including the effect of direction to lake as a function of distance from lakeshore and amount of surrounding water. Our results point to a strong, but complex, bottom-up control of local wildfire activity based on the configuration of natural firebreaks. In fact, fire rotation periods predicted for one area varied more than 15-fold (<47 to >700 years depending on local patterns in lakes. Old-growth forests within this fire-prone ecosystem are therefore likely to depend on the surrounding configuration of larger lakes.

  14. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web

    International Nuclear Information System (INIS)

    Kwon, Sae Yun; Blum, Joel D.; Nadelhoffer, Knute J.; Timothy Dvonch, J.; Tsui, Martin Tsz-Ki

    2015-01-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ 202 Hg and Δ 199 Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ 202 Hg and Δ 199 Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ 202 Hg and Δ 199 Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ 199 Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~ 20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ 202 Hg and Δ 199 Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ 199 Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ 199 Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative importance of MMHg sources and complex Hg transfer

  15. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sae Yun, E-mail: saeyunk@umich.edu [Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave, Ann Arbor, MI 48109 (United States); Blum, Joel D. [Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave, Ann Arbor, MI 48109 (United States); Department of Ecology and Evolutionary Biology, University of Michigan, 830 N. University Ave, Ann Arbor, MI 48109 (United States); Nadelhoffer, Knute J. [Department of Ecology and Evolutionary Biology, University of Michigan, 830 N. University Ave, Ann Arbor, MI 48109 (United States); Timothy Dvonch, J. [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Tsui, Martin Tsz-Ki [Department of Biology, University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27402 (United States)

    2015-11-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ{sup 202}Hg and Δ{sup 199}Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ{sup 202}Hg and Δ{sup 199}Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ{sup 202}Hg and Δ{sup 199}Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ{sup 199}Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~ 20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ{sup 202}Hg and Δ{sup 199}Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ{sup 199}Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ{sup 199}Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative

  16. An outlook for sustainable forest bioenergy production in the Lake States

    International Nuclear Information System (INIS)

    Becker, Dennis R.; Skog, Kenneth; Hellman, Allison; Halvorsen, Kathleen E.; Mace, Terry

    2009-01-01

    The Lake States region of Minnesota, Wisconsin and Michigan offers significant potential for bioenergy production. We examine the sustainability of regional forest biomass use in the context of existing thermal heating, electricity, and biofuels production, projected resource needs over the next decade including existing forest product market demand, and impacts on price and feasibility. Assuming $36 per dry tonne at roadside, 4.1 million dry tonnes of forest biomass could be available region-wide. However, less is likely available due to localized environmental and forest cover type constraints, and landowner willingness to harvest timber. Total projected demand of 5.7 million dry tonnes, based on current and announced industry capacity, exceeds estimates of biomass availability, which suggests that anticipated growth in the forest-based bioeconomy may be constrained. Attaining projected demand will likely require a combination of higher cost feedstocks, integration of energy and non-energy uses, and careful management to meet environmental constraints. State distinctions in biomass harvest guidelines and the propensity for third-party forest certification will be critical in providing environmental safeguards. The cumulative effect of policy initiatives on biomass competition are discussed in the context of an emerging Lake States bioeconomy.

  17. Carbon dynamics in lakes of the boreal forest under a changing climate

    Energy Technology Data Exchange (ETDEWEB)

    Benoy, G.; Wrona, F. [Environment Canada, Saskatoon, SK (Canada). National Water Research Inst.; Cash, K. [Environment Canada, Saskatoon, SK (Canada). Prairie and Northern Wildlife Research Centre; McCauley, E. [Calgary Univ., AB (Canada). Dept. of Biology

    2007-09-15

    This article reviewed factors influencing lake ecosystem carbon dynamics in boreal forest regions and identified research areas needed to accurately forecast the impacts of climate change on carbon pools and flux rates. The review suggested that carbon pools in profundal and littoral sediments across the boreal forest should be identified. Climate change experiments should be conducted to quantify ecosystem carbon dynamics as well as changes in aquatic food web structures. Whole system experiments are also needed to examine the hydrologic and bio-geochemical conditions in which allochthonous carbon is integrated into food webs in potentially drier climates. Results also indicated the need for a watershed-scale assessment of carbon budgets for lakes in transitional zones between boreal forests, prairies, parklands, forests, and tundra. It was concluded that studies are also needed to investigate the integration of lacustrine carbon pools and flux rates on carbon budgets at both the local watershed and boreal forest biome scale. 113 refs., 3 figs.

  18. An outlook for sustainable forest bioenergy production in the Lake States

    Science.gov (United States)

    Dennis R. Becker; Kenneth Skog; Allison Hellman; Kathleen E. Halvorsen; Terry Mace

    2009-01-01

    The Lake States region of Minnesota, Wisconsin and Michigan offers significant potential for bioenergy production. We examine the sustainability of regional forest biomass use in the context of existing thermal heating, electricity, and biofuels production, projected resource needs over the next decade including existing forest product market demand, and impacts on...

  19. Release of CO{sub 2} and CH{sub 4} from small wetland lakes in western Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Repo, M.E.; Huttunen, J.T.; Martikainen, P.J. [Univ. of Kuopio, Dept. of Env ironmental Science, FI-70211 Kuopio (Finland); Naumov, A.V.; Chichulin, A.V. [I nst. of Soil Science and Agrochemistry, Russian Academy of Science, 630099 Novos ibirsk (Russian Federation); Lapshina, E.D. [Yugra State Univ., 628012, Khanty-Mansiysk (Russian Federation); Bleuten , W. [Utrecht Univ., Dept. of Physical Geography,3508 TC Utrecht (Netherlands)

    2007-11-15

    CO{sub 2} and CH{sub 4} fluxes were measured from three small wetland lakes located in the middle taiga and forest tundra zones on West Siberian Lowlands (WSL), the world's largest wetland area. Fluxes were measured during summer 2005 using floating chambers and were validated against the thin boundary layer model based on the relationship between gas exchange and wind speed. All studied lakes were supersaturated with CO{sub 2} and CH{sub 4}, and acted on a seasonal basis as sources of these greenhouse gases to the atmosphere. Daily mean CO{sub 2} fluxes measured with chambers ranged from near the zero to 3.1 g CO{sub 2}/m{sup 2}/d and corresponding CH{sub 4} fluxes from 1.1 to 120 mg CH{sub 4}/m{sup 2}/d. CH{sub 4} ebullition (0.65-11 mg CH{sub 4}/m{sup 2}/d) was detected in two of the lakes. Total carbon evasion from the studied lakes during the active season was 23-66 g C/m{sup 2}, of which more than 90% was released as CO{sub 2}-C. The carbon loss per unit area from the studied lakes was of similar magnitude as previously reported values of net carbon uptake of Siberian peatlands. This emphasizes the importance of small water-bodies in the carbon balance of West Siberian landscape.

  20. Family forest landowners' interest in forest carbon offset programs: Focus group findings from the Lake States, USA

    Science.gov (United States)

    Kristell A. Miller; Stephanie A. Snyder; Mike A. Kilgore; Mae A. Davenport

    2014-01-01

    In 2012, focus groups were organized with individuals owning 20+ acres in the Lake States region of the United States (Michigan, Minnesota, and Wisconsin) to discuss various issues related to forest carbon offsetting. Focus group participants consisted of landowners who had responded to an earlier mail-back survey (2010) on forest carbon offsets. Two focus groups were...

  1. Effects of lakes and reservoirs on annual river nitrogen, phosphorus, and sediment export in agricultural and forested landscapes

    Science.gov (United States)

    Powers, Stephen M.; Robertson, Dale M.; Stanley, Emily H.

    2014-01-01

    Recently, effects of lakes and reservoirs on river nutrient export have been incorporated into landscape biogeochemical models. Because annual export varies with precipitation, there is a need to examine the biogeochemical role of lakes and reservoirs over time frames that incorporate interannual variability in precipitation. We examined long-term (~20 years) time series of river export (annual mass yield, Y, and flow-weighted mean annual concentration, C) for total nitrogen (TN), total phosphorus (TP), and total suspended sediment (TSS) from 54 catchments in Wisconsin, USA. Catchments were classified as small agricultural, large agricultural, and forested by use of a cluster analysis, and these varied in lentic coverage (percentage of catchment lake or reservoir water that was connected to river network). Mean annual export and interannual variability (CV) of export (for both Y and C) were higher in agricultural catchments relative to forested catchments for TP, TN, and TSS. In both agricultural and forested settings, mean and maximum annual TN yields were lower in the presence of lakes and reservoirs, suggesting lentic denitrification or N burial. There was also evidence of long-term lentic TP and TSS retention, especially when viewed in terms of maximum annual yield, suggesting sedimentation during high loading years. Lentic catchments had lower interannual variability in export. For TP and TSS, interannual variability in mass yield was often >50% higher than interannual variability in water yield, whereas TN variability more closely followed water (discharge) variability. Our results indicate that long-term mass export through rivers depends on interacting terrestrial, aquatic, and meteorological factors in which the presence of lakes and reservoirs can reduce the magnitude of export, stabilize interannual variability in export, as well as introduce export time lags.

  2. Wind variability and sheltering effects on measurements and modeling of air-water exchange for a small lake

    Science.gov (United States)

    Markfort, Corey D.; Resseger, Emily; Porté-Agel, Fernando; Stefan, Heinz

    2014-05-01

    Lakes with a surface area of less than 10 km2 account for over 50% of the global cumulative lake surface water area, and make up more than 99% of the total number of global lakes, ponds, and wetlands. Within the boreal regions as well as some temperate and tropical areas, a significant proportion of land cover is characterized by lakes or wetlands, which can have a dramatic effect on land-atmosphere fluxes as well as the local and regional energy budget. Many of these small water bodies are surrounded by complex terrain and forest, which cause the wind blowing over a small lake or wetland to be highly variable. Wind mixing of the lake surface layer affects thermal stratification, surface temperature and air-water gas transfer, e.g. O2, CO2, and CH4. As the wind blows from the land to the lake, wake turbulence behind trees and other shoreline obstacles leads to a recirculation zone and enhanced turbulence. This wake flow results in the delay of the development of wind shear stress on the lake surface, and the fetch required for surface shear stress to fully develop may be ~O(1 km). Interpretation of wind measurements made on the lake is hampered by the unknown effect of wake turbulence. We present field measurements designed to quantify wind variability over a sheltered lake. The wind data and water column temperature profiles are used to evaluate a new method to quantify wind sheltering of lakes that takes into account lake size, shape and the surrounding landscape features. The model is validated against field data for 36 Minnesota lakes. Effects of non-uniform sheltering and lake shape are also demonstrated. The effects of wind sheltering must be included in lake models to determine the effect of wind-derived energy inputs on lake stratification, surface gas transfer, lake water quality, and fish habitat. These effects are also important for correctly modeling momentum, heat, moisture and trace gas flux to the atmosphere.

  3. Organic matter fuel briquettes as a forest conservation tool in Lake ...

    African Journals Online (AJOL)

    Organic matter fuel briquettes as a forest conservation tool in Lake Malawi National Park: research note. ... Open Access DOWNLOAD FULL TEXT ... towards fuel briquettes, cost is the limiting factor when people choose their fuel source.

  4. Vegetation Diversity Quality in Mountainous Forest of Ranu Regulo Lake Area, Bromo Tengger Semeru National Park, East Java

    Directory of Open Access Journals (Sweden)

    Jehan Ramdani Hariyati

    2012-01-01

    Full Text Available Aim of this research was to study vegetation diversity quality in mountainous forest of Ranu Regulo Lake area in Bromo Tengger Semeru National Park (TNBTS, East Java. Field observation was carried out by vegetation analysis using sampling plots of 25x25 m2 for trees, 5x5 m2 for poles, 1x1 m2 for ground surface plants. Community structure of each lake side was determined by calculating vegetation's density, basal area, frequency, important value and stratification of species. While vegetations diversity was estimated by taxa richness, Shannon-Wiener diversity index, and rate of endemism. Each lake side forests were compared by Morisita community similarity index. Data were tabulated by Microsoft Excel 2007. The result showed that based on existed vegetation, mountainous forest surrounding Ranu Regulo Lake consisted of four ecosystems, i.e. heterogenic mountainous forest, pine forest, acacia forest and bushes. Bushes Area has two types of population, edelweiss and Eupatorium odoratum invaded area. Vegetation diversity quality in heterogenic mountainous forest of Ranu Regulo TNBTS was the highest, indicated by its multi-stratification to B stratum trees of 20-30m high. Heterogenic mountainous forest’s formation was Acer laurinum and Acmena accuminatissima for trees, Chyatea for poles. Taxa richness was found 59 species and 30 families, while the others were found below 28 species and 17 families. Diversity Index of heterogenic mountainous forest is the highest among others for trees is 2.31 and 3.24 for poles and second in bushes (H=3.10 after edelweiss ecosystem (H=3.39. Highest rate of endemism reached 100% for trees in heterogenic mountainous forest, 87% for poles in edelweiss area and 89% for bushes also in heterogenic mountainous forest. Trees, poles and herbs most similarity community showed by pine and acacia forest. Based on those five characters, vegetation diversity quality in Ranu Regulo Lake area was medium for heterogenic mountainous

  5. Holocene vegetation dynamics of Taiga forest in the Southern Altai Mountains documented by sediments from Kanas Lake

    Science.gov (United States)

    Huang, X.; Chen, F.

    2016-12-01

    The Chinese Altai is the southern limit of the Taiga forest of the continent, and regional vegetation dynamics during the Holocene will help us to understand regional climate changes, such as the Siberian High variations. Here we present a pollen-based vegetation and climate reconstruction from a well dated sediment core from Kanas Lake, a deep glacial moraine dammed lake in the Southern Altai Mountains (Chinese Altai). The 244-cm-long sequence spans the last 13,500 years, and the chronology is based on nine accelerator mass spectrometry radiocarbon dates from terrestrial plant macrofossils. At least five stages of regional vegetation history are documented: (i) From 13.5 to 11.7 ka (1 ka = 1000 cal yr BP), Kanas Lake region was occupied by steppe dominated by Artemisia, Chenopodiaceae and grass pollen, with low tree coverage. (ii) From 11.7 to 8.5 ka, regional forest build up dramatically indicated by increasing tree pollen percentages, including Picea, Larix, and the highest Junipers, with decreasing Artemisia and increasing Chenopodiaceae. (iii) From 8.5 to 7.2 ka, the forest around the lake became dense with the maximum content of Picea and Betula pollen types. And the steppe pollen types reached their lowest values. (iv) From 7.2 to 4 ka, as a typical tree species of Taiga forest, Larix pollen percentage became much higher than previous stage, and the sum of trees & shrubs pollen types decreased, which possibly indicated cooler and wetter climate (v) After 4 ka, trees & shrubs (e.g. Betula, Junipers) pollen types decreased, with increasing Artemisia and decreasing Chenopodiaceae, which might indicated more humid and cooler climate in the late Holocene. Comparing to the other pollen records in the Altai Mountains, Lake Grusha and Lake Hoton had recorded a slightly different process of vegetation evolution in the early Holocene, where forest was built up in the northern side of the Chinese Altai faster than that of the Kanas Lake area. And the difference could

  6. Forest changes since Euro-American settlement and ecosystem restoration in the Lake Tahoe Basin, USA

    Science.gov (United States)

    Alan H. Taylor

    2007-01-01

    Pre Euro-American settlement forest structure and fire regimes for Jeffrey pine-white fir, red fir-western white pine, and lodgepole pine forests were quantified using stumps from trees cut in the 19th century to establish a baseline reference for ecosystem management in the Lake Tahoe Basin. Contemporary forests varied in different ways compared...

  7. Fire effects on soils in Lake States forests: A compilation of published research to facilitate long-term investigations

    Science.gov (United States)

    Jessica Miesel; P. Goebel; R. Corace; David Hix; Randall Kolka; Brian Palik; David. Mladenoff

    2012-01-01

    Fire-adapted forests of the Lake States region are poorly studied relative to those of the western and southeastern United States and our knowledge base of regional short- and long-term fire effects on soils is limited. We compiled and assessed the body of literature addressing fire effects on soils in Lake States forests to facilitate the re-measurement of previous...

  8. Small-scale distribution and diel vertical migration of zooplankton in a shallow lake (Lake Naardermeer, the Netherlands)

    NARCIS (Netherlands)

    Cerbin, S.; Balayla, D.; Van de Bund, W.J.

    2003-01-01

    Small scale distribution and diurnal migration of zooplankton were investigated in lake Naardermeer, a shallow lake largely covered by uniform Chara beds. For sampling, pattern samplers with a number of inverted funnels facing towards the lake bottom and held in a frame were used. Samplers were

  9. Littoral macroinvertebrates of acidified lakes in the Bohemian Forest

    Czech Academy of Sciences Publication Activity Database

    Ungermanová, L.; Kolaříková, K.; Stuchlík, E.; Senoo, T.; Horecký, J.; Kopáček, Jiří; Chvojka, P.; Tátosová, J.; Bitušík, P.; Fjellheim, A.

    2014-01-01

    Roč. 69, č. 9 (2014), s. 1190-1201 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA526/09/0567; GA ČR(CZ) GA206/07/1200 Grant - others:EC(XE) EURO-LIMPACS GOCE-CT-2003-505540 Institutional support: RVO:60077344 Keywords : lakes * macroinvertebrates * acidification * recovery * forest catchment Subject RIV: DJ - Water Pollution ; Quality Impact factor: 0.827, year: 2014

  10. Pyrogenic Transformations of the Baikal Lake Forests. Retrospective and Contemporary Issues

    Directory of Open Access Journals (Sweden)

    M. D. Yevdokimenko

    2014-06-01

    Full Text Available In the forests of the Baikal Lake basin annual fire activity historically has been higher as compared to surrounding forest areas due to specific climatic conditions and altitude-controlled vegetation structure. The regional forests, predominantly light coniferous, develop under a high or, in dry years, extreme-fire-activity regime. Common pine and larch tree stands of fire origin are periodically thinned by fire. The productivity of the fire-intact parts of such stands decreases as a result of fire-caused soil condition disturbances. In extreme fire years, large fires cover landscapes and lead to irreversible forest ecosystem degradation and, hence, to local deforestation. In the past, forest fire activity and area burned increased with increasing use of the regional forests beginning with hunting, wood extraction by dwellers of local settlements, Trans-Siberian Rail Road building and, finally, industrial-scale logging. In 1970–1980, the regional fire situation was successfully controlled due to improvements of forest use and protection. However, the recently relaxed forest economy standards have resulted in loss of the progress achieved.

  11. Estimation of unregulated monthly, annual, and peak streamflows in Forest City Stream and lake levels in East Grand Lake, United States-Canada border between Maine and New Brunswick

    Science.gov (United States)

    Lombard, Pamela J.

    2018-04-30

    The U.S. Geological Survey, in cooperation with the International Joint Commission, compiled historical data on regulated streamflows and lake levels and estimated unregulated streamflows and lake levels on Forest City Stream at Forest City, Maine, and East Grand Lake on the United States-Canada border between Maine and New Brunswick to study the effects on streamflows and lake levels if two or all three dam gates are left open. Historical regulated monthly mean streamflows in Forest City Stream at the outlet of East Grand Lake (referred to as Grand Lake by Environment Canada) fluctuated between 114 cubic feet per second (ft3 /s) (3.23 cubic meters per second [m3 /s]) in November and 318 ft3 /s (9.01 m3 /s) in September from 1975 to 2015 according to Environment Canada streamgaging data. Unregulated monthly mean streamflows at this location estimated from regression equations for unregulated sites range from 59.2 ft3 /s (1.68 m3 /s) in September to 653 ft3 /s (18.5 m3 /s) in April. Historical lake levels in East Grand Lake fluctuated between 431.3 feet (ft) (131.5 meters [m]) in October and 434.0 ft (132.3 m) in May from 1969 to 2016 according to Environment Canada lake level data for East Grand Lake. Average monthly lake levels modeled by using the estimated hydrology for unregulated flows, and an outflow rating built from a hydraulic model with all gates at the dam open, range from 427.7 ft (130.4 m) in September to 431.1 ft (131.4 m) in April. Average monthly lake levels would likely be from 1.8 to 5.4 ft (0.55 to 1.6 m) lower with the gates at the dam opened than they have been historically. The greatest lake level changes would be from June through September.

  12. Subfossil Cladocera and pollen as indicators of natural and anthropogenic trophic changes of Lake Jelonek (Tuchola Forest, N Poland during the Holocene

    Directory of Open Access Journals (Sweden)

    Edyta Zawisza

    2016-12-01

    Full Text Available Lake Jelonek is a small lake located in central northern Poland, in the Tuchola Forest. The sediments of the lake represent a natural archive that offers insights into the natural history of the region from the Late Glacial to present. In winter 2002, a 1330 cm long sediment core was recovered from the deepest part of lake. Using a multiproxy approach (cladocerans, pollen and basic geochemistry, we reconstructed trophic status changes through the last ~15,000 years. Special attention was devoted to the evaluation of nutrient contributions to the lake from natural and anthropogenic sources. The Cladocera analyses yielded a total of 29 species belonging to five families (Bosminidae, Daphniidae, Leptodoridae, Chydoridae, Sididae, with planktonic species representing more than 60% of Cladocera relative abundance throughout the core. The pollen results suggested four periods of increased human activity, so-called settlement phases. The first traces of human activity in the basin of Lake Jelonek appeared in the Atlantic period and were related with Mesolithic and Neolithic settlements. The second (Bronze Age and the third (Iron Age settlement phases are well marked by the paleolimnological proxies studied. This time period clearly manifested on the lake waters as an increasing trophy level probably caused by human-associated discharges of nutrients to the lake. After the third settlement phase cladoceran data indicated a significant decrease in the lake trophic level and the pollen data showed a recovery of forest cover. The fourth period of human economic activity during the early Middle Age was characterized by deforestation associated with land reclamation for grazing and cultivation of cereals, and the subsequent nutrient enrichment of lake waters. According to our results, the biological development of Lake Jelonek was determined by climate changes from Late Glacial up to the Atlantic period. Contrastingly, the most important driver for the lake

  13. Identifying the tundra-forest border in the stomate record: an analysis of lake surface samples from the Yellowknife area, Northwest Territories, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, B.C.S. [Minnesota Univ., Minneapolis, MN (United States). Limnological Research Center; MacDonald, G.M. [California Univ., Los Angeles, CA (United States). Dept. of Botanical Sciences; Moser, K.A. [McMaster Univ., Hamilton, ON (Canada)

    1996-05-01

    The relationship between conifer stomata and existing vegetation across tundra, forest-tundra, and closed zones in the Yellowknife area of the Northwest Territories was studied. Conifer stomata were identified in surface samples from lakes in the treeline zone, but were absent in samples from tundra lakes. Stomate analysis was recorded and the results were presented in a concentration diagram plotting stomate concentrations according to vegetation zone. Conifer stomate analysis was not able to resolve differences between forest-tundra and closed forest. Nevertheless, it was suggested that stomate analysis will become an important technique supplementing pollen analysis for reconstructing past tree-line changes since the presence of stomata in lakes make it possible to separate the tundra from forest-tundra and closed forest. The limited dispersal of conifer stomata permitted a better resolution of tree-line boundaries than did pollen. 13 refs., 3 figs.

  14. Long-term management impacts on carbon storage in Lake States forests

    Science.gov (United States)

    Matthew Powers; Randall Kolka; Brian Palik; Rachel McDonald; Martin. Jurgensen

    2011-01-01

    We examined carbon storage following 50+ years of forest management in two long-term silvicultural studies in red pine and northern hardwood ecosystems of North America’s Great Lakes region. The studies contrasted various thinning intensities (red pine) or selection cuttings, shelterwoods, and diameter-limit cuttings (northern hardwoods) to unmanaged controls of...

  15. Modelling hourly rates of evaporation from small lakes

    Directory of Open Access Journals (Sweden)

    R. J. Granger

    2011-01-01

    Full Text Available The paper presents the results of a field study of open water evaporation carried out on three small lakes in Western and Northern Canada. In this case small lakes are defined as those for which the temperature above the water surface is governed by the upwind land surface conditions; that is, a continuous boundary layer exists over the lake, and large-scale atmospheric effects such as entrainment do not come into play. Lake evaporation was measured directly using eddy covariance equipment; profiles of wind speed, air temperature and humidity were also obtained over the water surfaces. Observations were made as well over the upwind land surface.

    The major factors controlling open water evaporation were examined. The study showed that for time periods shorter than daily, the open water evaporation bears no relationship to the net radiation; the wind speed is the most significant factor governing the evaporation rates, followed by the land-water temperature contrast and the land-water vapour pressure contrast. The effect of the stability on the wind field was demonstrated; relationships were developed relating the land-water wind speed contrast to the land-water temperature contrast. The open water period can be separated into two distinct evaporative regimes: the warming period in the Spring, when the land is warmer than the water, the turbulent fluxes over water are suppressed; and the cooling period, when the water is warmer than the land, the turbulent fluxes over water are enhanced.

    Relationships were developed between the hourly rates of lake evaporation and the following significant variables and parameters (wind speed, land-lake temperature and humidity contrasts, and the downwind distance from shore. The result is a relatively simple versatile model for estimating the hourly lake evaporation rates. The model was tested using two independent data sets. Results show that the modelled evaporation follows the observed values

  16. Seasonal photochemical transformations of nitrogen species in a forest stream and lake.

    Directory of Open Access Journals (Sweden)

    Petr Porcal

    Full Text Available The photochemical release of inorganic nitrogen from dissolved organic matter is an important source of bio-available nitrogen (N in N-limited aquatic ecosystems. We conducted photochemical experiments and used mathematical models based on pseudo-first-order reaction kinetics to quantify the photochemical transformations of individual N species and their seasonal effects on N cycling in a mountain forest stream and lake (Plešné Lake, Czech Republic. Results from laboratory experiments on photochemical changes in N speciation were compared to measured lake N budgets. Concentrations of organic nitrogen (Norg; 40-58 µmol L-1 decreased from 3 to 26% during 48-hour laboratory irradiation (an equivalent of 4-5 days of natural solar insolation due to photochemical mineralization to ammonium (NH4+ and other N forms (Nx; possibly N oxides and N2. In addition to Norg mineralization, Nx also originated from photochemical nitrate (NO3- reduction. Laboratory exposure of a first-order forest stream water samples showed a high amount of seasonality, with the maximum rates of Norg mineralization and NH4+ production in winter and spring, and the maximum NO3- reduction occurring in summer. These photochemical changes could have an ecologically significant effect on NH4+ concentrations in streams (doubling their terrestrial fluxes from soils and on concentrations of dissolved Norg in the lake. In contrast, photochemical reactions reduced NO3- fluxes by a negligible (<1% amount and had a negligible effect on the aquatic cycle of this N form.

  17. Birds of isolated small forests in Uganda | Dranzoa | Scopus: Journal ...

    African Journals Online (AJOL)

    There is also a strong indication of species turnover amongst the forest interior birds in these forests. The fact that, together and over time these small forests supported 37 forest interior species, suggests that, collectively, small forests (of which there are many in Uganda) do have conservation value. The evidence of species ...

  18. Challenge to the model of lake charr evolution: Shallow- and deep-water morphs exist within a small postglacial lake

    Science.gov (United States)

    Chavarie, Louise; Muir, Andrew M.; Zimmerman, Mara S.; Baillie, Shauna M.; Hansen, Michael J.; Nate, Nancy A.; Yule, Daniel L.; Middel, Trevor; Bentzen, Paul; Krueger, Charles C.

    2016-01-01

    All examples of lake charr (Salvelinus namaycush) diversity occur within the largest, deepest lakes of North America (i.e. > 2000 km2). We report here Rush Lake (1.3 km2) as the first example of a small lake with two lake charr morphs (lean and huronicus). Morphology, diet, life history, and genetics were examined to demonstrate the existence of morphs and determine the potential influence of evolutionary processes that led to their formation or maintenance. Results showed that the huronicus morph, caught in deep-water, had a deeper body, smaller head and jaws, higher eye position, greater buoyancy, and deeper peduncle than the shallow-water lean morph. Huronicus grew slower to a smaller adult size, and had an older mean age than the lean morph. Genetic comparisons showed low genetic divergence between morphs, indicating incomplete reproductive isolation. Phenotypic plasticity and differences in habitat use between deep and shallow waters associated with variation in foraging opportunities seems to have been sufficient to maintain the two morphs, demonstrating their important roles in resource polymorphism. Rush Lake expands previous explanations for lake charr intraspecific diversity, from large to small lakes and from reproductive isolation to the presence of gene flow associated with strong ecological drivers.

  19. Seasonal and inter-annual variations in methyl mercury concentrations in zooplankton from boreal lakes impacted by deforestation or natural forest fires.

    Science.gov (United States)

    Garcia, Edenise; Carignan, Richard; Lean, David R S

    2007-08-01

    We compared the effects of natural and anthropogenic watershed disturbances on methyl mercury (MeHg) concentration in bulk zooplankton from boreal Shield lakes. MeHg in zooplankton was monitored for three years in nine lakes impacted by deforestation, in nine lakes impacted by wildfire, and in twenty lakes with undisturbed catchments. Lakes were sampled during spring, mid- and late summer. MeHg in zooplankton showed a seasonal trend: concentrations were the lowest in spring, then peaked in mid-summer and decreased in late summer. Over the three study years, MeHg concentrations observed in mid-summer in zooplankton from forest harvested lakes were significantly higher than in reference and fire-impacted lakes, whereas differences between these two groups of lakes were not significant. The pattern of distribution of MeHg in zooplankton during the different seasons paralleled that of dissolved organic carbon (DOC), which is known as a vector of Hg from watershed soils to lake water. Besides DOC, MeHg in zooplankton also showed a positive significant correlation with epilimnetic temperature and sulfate concentrations. An inter-annual decreasing trend in MeHg was observed in zooplankton from reference and fire-impacted lakes. In forest harvested lakes, however, MeHg concentrations remained higher and nearly constant over three years following the impact. Overall these results indicate that the MeHg pulse observed in zooplankton following deforestation by harvesting is relatively long-lived, and may have repercussions to the accumulation of MeHg along the food chain. Therefore, potential effects of deforestation on the Hg contamination of fish should be taken into account in forest management practices.

  20. Ecology and potential for fishery of the small barbs (Cyprinidae, Teleostei) of Lake Tana, Ethiopia

    OpenAIRE

    Dejen, E.

    2003-01-01

    Lake Tana is by far the largest lake of Ethiopia and source of the Blue Nile. By feeding on zooplankton, small barbs (< 10 cm) occupy a central position in Lake Tana's ecosystem. Catching them could release pressure on the overexploited, unique species flock of large barbs (up to 100 cm). Aiming at small barbs, we need first to assess its possible impact on the food web and productivity. To advise on sustainable management, the biology and ecology of the small Barbus species in Lake Tana w...

  1. Cycling of acid and base cations in deciduous stands of Huntington Forest, New York, and Turkey Lakes, Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Foster, N W; Morrison, I K [Forestry Canada, Sault Ste. Marie, ON (Canada); Mitchell, M J [State Univ. of New York, Syracuse, NY (USA); Shepard, J P [National Council of the Paper Industry for Air and Stream Improvement, Gainesville, FL (USA)

    1992-01-01

    Annual nutrient fluxes within two forests exposed to acidic deposition were compared for a 1-year period. Calcium (Ca{sup 2+}) was the dominant cation in throughfall and soil solutions from tolerant hardwood dominated Spodosols (Podzols) at both Huntington Forest (HF), New York, and the Turkey Lakes watershed (TLW), Ontario. There was a net annual export of Ca{sup 2+} and Mg{sup 2+} from the TLW soil, whereas base cation inputs in precipitation equalled outputs at HF. In 1986, leaching losses of base cations were five times greater at TLW than at HF. A higher percentage of the base cation reserves was leached from the soil at TLW (5%) than at HF (1%). Relative to throughfall, aluminum concentrations increased in forest-floor and mineral-soil solutions, especially at HF. The TLW soil appears more sensitive to soil acidification. Deposited atmospheric acidity, however, was small in comparison with native soil acidity (total and exchangeable) and the reserves of base cations in each soil. Soil acidity and base saturation, therefore, are likely only to change slowly. 57 refs., 1 fig., 5 tabs.

  2. Bibliography of publications and manuscripts relating to the Bohemian/Bavarian Forest lakes

    Czech Academy of Sciences Publication Activity Database

    Vrba, Jaroslav (ed.)

    2000-01-01

    Roč. 4, č. 4 (2000), s. 259-278 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. Č. Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727 Subject RIV: DA - Hydrology ; Limnology

  3. Temporal variation of phytoplankton in a small tropical crater lake, Costa Rica

    Directory of Open Access Journals (Sweden)

    Gerardo Umaña-Villalobos

    2010-12-01

    Full Text Available The temporal variation in lake’s phytoplankton is important to understand its general biodiversity. For tropical lakes, it has been hypothesized that they follow a similar pattern as temperate ones, on a much accelerated pace; nevertheless, few case studies have tried to elucidate this. Most studies in Costa Rica have used a monthly sampling scheme and failed in showing the expected changes. In this study, the phytoplankton of the small Barvas’s crater lake was followed for more than three years, first with monthly and later with weekly samplings, that covered almost two years. Additional information on temperature and oxygen vertical profiles was obtained on a monthly basis, and surface temperature was measured during weekly samplings around noon. Results showed that in spite of its shallow condition (max. depth: 7m and low surface temperature (11 to 19°C, the lake stratifies at least for brief periods. The phytoplankton showed both, rapid change periods, and prolonged ones of relative stasis. The plankton composition fluctuated between three main phases, one characterized by the abundance of small sized desmids (Staurastrum paradoxum, Cosmarium asphaerosporum, a second phase dominated by equally small cryptomonads (Chryptochrysis minor, Chroomonas sp. and a third phase dominated by the green alga Eutetramorus tetrasporus. Although data evidenced that monthly sampling could miss short term events, the temporal variation did not follow the typical dry and rainy seasons of the region, or any particular annual pattern. Year to year variation was high. As this small lake is located at the summit of Barva Volcano and receives the influence from both the Caribbean and the Pacific weather, seasonality at the lake is not clearly defined as in the rest of the country and short term variations in the local weather might have a stronger effect than broad seasonal trends. The occurrence of this short term changes in the phytoplankton of small tropical

  4. Small forest holdings could be combined for hunting leases

    Science.gov (United States)

    John J. Stransky; Lowell K. Halls

    1969-01-01

    Most forest land acreage in the South is in small holdings. Much-needed hunting land, and income for rural landowners, could be provided by combining small forest holdings into large units and teasing the hunting rights.

  5. Forest biomass estimated from MODIS and FIA data in the Lake States: MN, WI and MI, USA

    Science.gov (United States)

    Daolan Zheng; Linda S. Heath; Mark J. Ducey

    2007-01-01

    This study linked the Moderate Resolution Imaging Spectrometer and USDA Forest Service, Forest Inventory and Analysis (FIA) data through empirical models established using high-resolution Landsat Enhanced Thematic Mapper Plus observations to estimate aboveground biomass (AGB) in three Lake States in the north-central USA. While means obtained from larger sample sizes...

  6. Holocene evolution of lakes in the forest-tundra biome of northern Manitoba, Canada

    Science.gov (United States)

    Hobbs, William O.; Edlund, Mark B.; Umbanhowar, Charles E.; Camill, Philip; Lynch, Jason A.; Geiss, Christoph; Stefanova, Vania

    2017-03-01

    The late-Quaternary paleoenvironmental history of the western Hudson Bay region of Subarctic Canada is poorly constrained. Here, we present a regional overview of the post-glacial history of eight lakes which span the forest-tundra biome in northern Manitoba. We show that during the penultimate drainage phase of Lake Agassiz the lake water had an estimated pH of ∼6.0, with abundant quillwort (Isöetes spp.) along the lakeshore and littoral zone and some floating green algae (Botryococcus spp. and Pediastrum sp.). Based on multiple sediment proxies, modern lake ontogeny in the region commenced at ∼7500 cal yrs BP. Pioneering diatom communities were shaped by the turbid, higher alkalinity lake waters which were influenced by base cation weathering of the surrounding till following Lake Agassiz drainage. By ∼7000 cal yrs BP, soil development and Picea spp. establish and the lakes began a slow trajectory of acidification over the remaining Holocene epoch. The natural acidification of the lakes in this region is slow, on the order of several millennia for one pH unit. Each of the study lakes exhibit relatively stable aquatic communities during the Holocene Thermal Maximum, suggesting this period is a poor analogue for modern climatic changes. During the Neoglacial, the beginning of the post-Little Ice Age period represents the most significant climatic event to impact the lakes of N. Manitoba. In the context of regional lake histories, the rate of diatom floristic change in the last 200-300 years is unprecedented, with the exception of post-glacial lake ontogeny in some of the lakes. For nearly the entire history of the lakes in this region, there is a strong linkage between landscape development and the aquatic ecosystems; however this relationship appears to become decoupled or less strong in the post-LIA period. Significant 20th century changes in the aquatic ecosystem cannot be explained wholly by changes in the terrestrial ecosystem, suggesting that future

  7. Combining high-resolution satellite images and altimetry to estimate the volume of small lakes

    Science.gov (United States)

    Baup, F.; Frappart, F.; Maubant, J.

    2014-05-01

    This study presents an approach to determining the volume of water in small lakes (manager of the lake. Three independent approaches are developed to estimate the lake volume and its temporal variability. The first two approaches (HRBV and ABV) are empirical and use synchronous ground measurements of the water volume and the satellite data. The results demonstrate that altimetry and imagery can be effectively and accurately used to monitor the temporal variations of the lake (R2ABV = 0.98, RMSEABV = 5%, R2HRBV = 0.90, and RMSEABV = 7.4%), assuming a time-varying triangular shape for the shore slope of the lake (this form is well adapted since it implies a difference inferior to 2% between the theoretical volume of the lake and the one estimated from bathymetry). The third method (AHRBVC) combines altimetry (to measure the lake level) and satellite images (of the lake surface) to estimate the volume changes of the lake and produces the best results (R2AHRBVC = 0.98) of the three methods, demonstrating the potential of future Sentinel and SWOT missions to monitor small lakes and reservoirs for agricultural and irrigation applications.

  8. Ground-water quality of the surficial aquifer system and the upper Floridan Aquifer, Ocala National Forest and Lake County, Florida, 1990-99

    Science.gov (United States)

    Adamski, J.C.; Knowles, Leel

    2001-01-01

    Data from 217 ground-water samples were statistically analyzed to assess the water quality of the surficial aquifer system and Upper Floridan aquifer in the Ocala National Forest and Lake County, Florida. Samples were collected from 49 wells tapping the surficial aquifer system, 141 wells tapping the Upper Floridan aquifer, and from 27 springs that discharge water from the Upper Floridan aquifer. A total of 136 samples was collected by the U.S. Geological Survey from 1995 through 1999. These data were supplemented with 81 samples collected by the St. Johns River Water Management District and Lake County Water Resources Management from 1990 through 1998. In general, the surficial aquifer system has low concentrations of total dissolved solids (median was 41 milligrams per liter) and major ions. Water quality of the surficial aquifer system, however, is not homogeneous throughout the study area. Concentrations of total dissolved solids, many major ions, and nutrients are greater in samples from Lake County outside the Ocala National Forest than in samples from within the Forest. These results indicate that the surficial aquifer system in Lake County outside the Ocala National Forest probably is being affected by agricultural and (or) urban land-use practices. High concentrations of dissolved oxygen (less than 0.1 to 8.2 milligrams per liter) in the surficial aquifer system underlying the Ocala National Forest indicate that the aquifer is readily recharged by precipitation and is susceptible to surface contamination. Concentrations of total dissolved solids were significantly greater in the Upper Floridan aquifer (median was 182 milligrams per liter) than in the surficial aquifer system. In general, water quality of the Upper Floridan aquifer was homogeneous, primarily being a calcium or calciummagnesium- bicarbonate water type. Near the St. Johns River, the water type of the Upper Floridan aquifer is sodium-chloride, corresponding to an increase in total dissolved

  9. [Fleas on small mammals in the surrounding area of Erhai Lake].

    Science.gov (United States)

    Dong, Wen-Ge; Guo, Xian-Guo; Men, Xing-Yuan; Gong, Zheng-Da; Wu, Dian; Zhang, Zheng-Kun; Zhang, Li-Yun

    2009-12-01

    To investigate the distribution pattern, species diversity and community structure of fleas on small mammals in the surrounding area of Erhai Lake, and the relationship between fleas and their hosts. Different geographical areas surrounding the Erhai Lake in Yunnan were selected as investigated spots. Small mammals were captured with baited cages. The cage-traps were examined and re-baited each morning. All fleas on the hosts were collected and identified. The richness (S), evenness (J'), diversity index (H'), dominance index (C'), total ectoparasite infestation rate (Rpt), total ectoparasite infestation index (Ipt), and constituent ratio (Cr) were used to measure the community structure. Altogether, 3,303 small mammals and 3,243 fleas were collected. From the 21 species of small mammal hosts, 13 species of fleas were identified. In southern area of the Lake, the species richness (21 species of small mammals & 12 species of fleas) was highest among the three selected areas. Seventeen species of small mammals and 8 species of fleas were found in eastern area, and only 13 species of small mammals and 7 species of fleas found in the west. This implied the probable influences of ecological environments on the fleas and their corresponding hosts. The community structure of fleas on small mammals was complex. The species diversity, species composition, community structure and distribution pattern of fleas were simultaneously influenced by the hosts' body surface microenvironment and the macroenvironment (habitat). The fleas are commonly distributed in small mammals in the areas and their communities are related to host species and the habitats.

  10. Food Web Responses to Artificial Mixing in a Small Boreal Lake

    Directory of Open Access Journals (Sweden)

    Lauri Arvola

    2017-07-01

    Full Text Available In order to simulate food web responses of small boreal lakes to changes in thermal stratification due to global warming, a 4 year whole-lake manipulation experiment was performed. Within that time, period lake mixing was intensified artificially during two successive summers. Complementary data from a nearby lake of similar size and basic water chemistry were used as a reference. Phytoplankton biomass and chlorophyll a did not respond to the greater mixing depth but an increase was observed in the proportional abundance of diatoms, and the proportional abundance of cryptophytes also increased immediately after the onset of mixing. Obligate anoxic green sulphur bacteria vanished at the onset of mixing but gradually recovered after re-establishment of hypolimnetic anoxic conditions. No major effect on crustacean zooplankton was found, but their diversity increased in the metalimnion. During the mixing, the density of rotifers declined but protozoan density increased in the hypolimnion. Littoral benthic invertebrate density increased during the mixing due to Ephemeroptera, Asellus aquaticus and Chironomidae, whereas the density of Chaoborus larvae declined during mixing and lower densities were still recorded one year after the treatment. No structural changes in fish community were found although gillnet catches increased after the onset of the study. The early growth of perch (Perca fluviatilis increased compared to the years before the mixing and in comparison to the reference lake, suggesting improved food availability in the experimental lake. Although several food web responses to the greater mixing depth were found, their persistence and ecological significance were strongly dependent on the extent of the disturbance. To better understand the impacts of wind stress on small lakes, long term whole-lake experiments are needed.

  11. Looking Back to Move Forward: Collaborative Planning to Revise the Green Mountain and Finger Lakes National Forests Land and Resource Management Plans

    Directory of Open Access Journals (Sweden)

    Michael J Dockry

    2015-07-01

    Full Text Available The United States Department of Agriculture Forest Service (Forest Service manages 154 national forests and 20 grasslands in 44 states and Puerto Rico. National Forest Land and Resource Management Plans (forest plans form the basis for land and resource management of national forests in the United States. For more than a decade the Forest Service has been attempting to incorporate innovative, collaborative public involvement strategies into the process for revising forest plans. In 2012 and 2015 the Forest Service codified new regulations for developing, revising, and amending forest plans. Collaboration and public involvement are explicit goals of the new regulations. This paper briefly reviews the literature on collaborative planning on national forests and explores a successful collaborative planning process used by the Green Mountain and Finger Lakes National Forests, located in Vermont and New York respectively, to develop their 2006 forest plans. This paper shows how the Green Mountain and Finger Lakes National Forests developed parallel public and internal collaborative processes to build trust, relationships, and partnership, and discusses the implications for process design, capacity building, and facilitating agreements. By looking back at this successful case of collaborative forest planning, key lessons can provide ideas for developing collaborative processes for future planning efforts.

  12. Drought drove forest decline and dune building in eastern upper Michigan, USA, as the upper Great Lakes became closed basins

    Science.gov (United States)

    Loope, Walter L.; Loope, Henry M.; Goble, Ronald J.; Fisher, Timothy G.; Lytle, David E.; Legg, Robert J.; Wysocki, Douglas A.; Hanson, Paul R.; Young, Aaron R.

    2012-01-01

    Current models of landscape response to Holocene climate change in midcontinent North America largely reconcile Earth orbital and atmospheric climate forcing with pollen-based forest histories on the east and eolian chronologies in Great Plains grasslands on the west. However, thousands of sand dunes spread across 12,000 km2 in eastern upper Michigan (EUM), more than 500 km east of the present forest-prairie ecotone, present a challenge to such models. We use 65 optically stimulated luminescence (OSL) ages on quartz sand deposited in silt caps (n = 8) and dunes (n = 57) to document eolian activity in EUM. Dune building was widespread ca. 10–8 ka, indicating a sharp, sustained decline in forest cover during that period. This decline was roughly coincident with hydrologic closure of the upper Great Lakes, but temporally inconsistent with most pollen-based models that imply canopy closure throughout the Holocene. Early Holocene forest openings are rarely recognized in pollen sums from EUM because faint signatures of non-arboreal pollen are largely obscured by abundant and highly mobile pine pollen. Early Holocene spikes in nonarboreal pollen are recorded in cores from small ponds, but suggest only a modest extent of forest openings. OSL dating of dune emplacement provides a direct, spatially explicit archive of greatly diminished forest cover during a very dry climate in eastern midcontinent North America ca. 10–8 ka.

  13. Probing Small Lakes on Titan Using the Cassini RADAR Altimeter

    Science.gov (United States)

    Mastrogiuseppe, M.; Poggiali, V.; Hayes, A.; Lunine, J. I.; Seu, R.; Lorenz, R. D.; Mitri, G.; Mitchell, K. L.; Janssen, M. A.; Casarano, D.; Notarnicola, C.; Le Gall, A. A.

    2017-12-01

    The T126 Cassini's final flyby of Titan has offered a unique opportunity to observe an area in the Northern Polar terrain, where several small - medium size (10 - 50 km) hydrocarbon lakes are present and have been previously imaged by Cassini. The successful observation allowed the radar to operate at the closest approach over several small lakes, using its altimetry mode for the investigation of depth and liquid composition. Herein we present the result of a dedicate processing previously applied to altimetric data acquired over Ligeia Mare where the radar revealed the bathymetry and composition of the sea [1,2]. We show that, the optimal geometry condition met during the T126 fly-by allowed the radar to probe Titan's lakes revealing that such small liquid bodies can exceed one-hundred meters of depth. [1] M. Mastrogiuseppe et al. (2014, Mar.). The bathymetry of a Titan Sea. Geophysical Research Letters. [Online]. 41 (5), pp. 1432-1437. Available: http://dx.doi.org/10.1002/2013GL058618 [2] M.Mastrogiuseppe et al. (2016, Oct). Radar Sounding Using the Cassini Altimeter: Waveform Modeling and Monte Carlo Approach for Data Inversion of Observations of Titan's Seas, IEEE Transactions On Geoscience And Remote Sensing, Vol. 54, No. 10, doi: 10.1109/TGRS.2016.2563426.

  14. On the radiocesium behavior in a small humic lake (Lithuania)

    International Nuclear Information System (INIS)

    Tarasiuk, N.; Koviazina, E.; Karpicz, R.; Moisejenkova, A.; Astrauskiene, N.

    2009-01-01

    Peculiarities of radiocesium contamination of a small humic lake, which became meromictic some thirty-five years ago due to the inflow of a large amount of humic water, are presented. The lake consists of two separate water layers, which do not intermix. A lower water layer of the lake below some 3-m depth is stagnant and anaerobic, and radiocesium load of the sediments is mainly caused by nuclear weapons fallout. The radiocesium load of the sediments of the upper monomictic water layer is significantly larger due to additional contamination after the Chernobyl accident. Radiocesium activity concentrations in lake water increase with depth, and even in the surface layer, they are commonly the largest among the neighboring lakes with transparent water. It is shown that bottom areas of the monomictic part of the lake with the elevated radiocesium deepening into sediments are related to the favorite sites of the tench (Tinca tinca) winter torpor. Sediment bioturbation and redistribution due to tench activities distort naturally formed radiocesium vertical profiles and they cannot be used for estimations of sedimentation rates and sediment chronology. The studied lake can be useful as an analogous model in analyzing structural and radiological consequences of humic water inflows to closed lakes. Concerning extreme radiological situations in closed humic lakes related to their specific vertical structure, they may be treated as critical objects in assessing the risk to humans after radionuclide deposition events. (authors)

  15. Change in the forested and developed landscape of the Lake Tahoe basin, California and Nevada, USA, 1940-2002

    Science.gov (United States)

    Raumann, C.G.; Cablk, Mary E.

    2008-01-01

    The current ecological state of the Lake Tahoe basin has been shaped by significant landscape-altering human activity and management practices since the mid-1850s; first through widespread timber harvesting from the 1850s to 1920s followed by urban development from the 1950s to the present. Consequences of landscape change, both from development and forest management practices including fire suppression, have prompted rising levels of concern for the ecological integrity of the region. The impacts from these activities include decreased water quality, degraded biotic communities, and increased fire hazard. To establish an understanding of the Lake Tahoe basin's landscape change in the context of forest management and development we mapped, quantified, and described the spatial and temporal distribution and variability of historical changes in land use and land cover in the southern Lake Tahoe basin (279 km2) from 1940 to 2002. Our assessment relied on post-classification change detection of multi-temporal land-use/cover and impervious-surface-area data that were derived through manual interpretation, image processing, and GIS data integration for four dates of imagery: 1940, 1969, 1987, and 2002. The most significant land conversion during the 62-year study period was an increase in developed lands with a corresponding decrease in forests, wetlands, and shrublands. Forest stand densities increased throughout the 62-year study period, and modern thinning efforts resulted in localized stand density decreases in the latter part of the study period. Additionally forests were gained from succession, and towards the end of the study period extensive tree mortality occurred. The highest rates of change occurred between 1940 and 1969, corresponding with dramatic development, then rates declined through 2002 for all observed landscape changes except forest density decrease and tree mortality. Causes of landscape change included regional population growth, tourism demands

  16. Mercury bioaccumulation in fishes from subalpine lakes of the Wallowa-Whitman National Forest, northeastern Oregon and western Idaho

    Science.gov (United States)

    Eagles-Smith, Collin A.; Herring, Garth; Johnson, Branden L.; Graw, Rick

    2013-01-01

    Mercury (Hg) is a globally distributed pollutant that poses considerable risks to human and wildlife health. Over the past 150 years since the advent of the industrial revolution, approximately 80 percent of global emissions have come from anthropogenic sources, largely fossil fuel combustion. As a result, atmospheric deposition of Hg has increased by up to 4-fold above pre-industrial times. Because of their isolation, remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited Hg through freshwater food webs, as well as for evaluating the relative importance of Hg loading versus landscape influences on Hg bioaccumulation. The increase in Hg deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in Hg emissions may propagate to changes in Hg bioaccumulation and ecological risk. In this study, we evaluated Hg concentrations in fishes of high-elevation, sub-alpine lakes in the Wallowa-Whitman National Forest in northeastern Oregon and western Idaho. Our goals were to (1) assess the magnitude of Hg contamination in small-catchment lakes to evaluate the risk of atmospheric Hg to human and wildlife health, (2) quantify the spatial variability in fish Hg concentrations, and (3) determine the ecological, limnological, and landscape factors that are best correlated with fish total mercury (THg) concentrations in these systems. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. Importantly, our top statistical model explained 87 percent of the variability in fish THg concentrations among lakes with four key landscape and limnological variables— catchment conifer density (basal area of conifers within a lake’s catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. The basal area of conifers

  17. Glaciation in the surroundings of Prášilské Lake (Bohemian Forest, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Mentlík, P.; Minár, J.; Břízová, E.; Lisá, Lenka; Tábořík, P.; Stacke, V.

    2010-01-01

    Roč. 117, 1/2 (2010), s. 181-194 ISSN 0169-555X Institutional research plan: CEZ:AV0Z30130516 Keywords : Bohemian Forest * Pleistocene glaciations * Prášilské Lake * Šumava * sedimentology * chronology Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.352, year: 2010

  18. Role of storms and forest practices in sedimentation of an Oregon Coast Range lake

    Science.gov (United States)

    Richardson, K.; Hatten, J. A.; Wheatcroft, R. A.; Guerrero, F. J.

    2014-12-01

    The design of better management practices in forested watersheds to face climate change and the associated increase in the frequency of extreme events requires a better understanding of watershed responses to extreme events in the past and also under management regimes. One of the most sensitive watershed processes affected is sediment yield. Lake sediments record events which occur in a watershed and provide an opportunity to examine the interaction of storms and forest management practices in the layers of the stratigraphy. We hypothesize that timber harvesting and road building since the 1900s has resulted in increases in sedimentation; however, the passage of the Oregon Forest Practices Act (OFPA) in 1972 has led to a decrease in sedimentation. Sediment cores were taken at Loon Lake in the Oregon Coast Range. The 32-m deep lake captures sediment from a catchment highly impacted by recent land use and episodic Pacific storms. We can use sedimentological tools to measure changes in sediment production as motivated by extreme floods before settlement, during a major timber harvesting period, and after installation of forestry Best Management Practices. Quantification of changes in particle size and elemental composition (C, N, C/N) throughout the cores can elucidate changes in watershed response to extreme events, as can changes in layer thickness. Age control in the cores is being established by Cesium-137 and radiocarbon dating. Given the instrumental meteorological data and decadal climate reconstructions, we will disentangle climate driven signals from changes in land use practices. The sediment shows distinct laminations and varying thickness of layers throughout the cores. Background deposition is composed of thin layers (events to determine if the OFPA is having an effect on reducing sedimentation rates as a result of extreme magnitude storm events.

  19. The necessity of management in a lake of the Atlantic Forest biodiversity hotspot: nitrogen levels connected to a persistent bloom of Cylindrospermopsis raciborskii

    Directory of Open Access Journals (Sweden)

    Cleber Cunha Figueredo

    2016-01-01

    Full Text Available ABSTRACT Conservational studies of the threatened Atlantic Forest biome are frequently restricted to terrestrial ecosystems. We know little about the water bodies, specially considering that this biome covers the third largest system of lakes in Brazil. Some of these lakes are located inside the protected "Rio Doce State Park", but many others are found outside this reserve. These external lakes are seldom studied, but understanding their response to human activities is essential for the conservation and the protection of the lakes inside the Park. We evaluated the effects of degradation in a lake outside the Park, which shows a constant bloom of the toxic invasive cyanobacteria Cylindrospermopsis raciborskii. Phytoplankton, climate and physico-chemical variables were assessed from 2011 to 2013 to evaluate which were the major determinants of the lake dynamics. Despite the seasonal changes, the lake was always eutrophic, and cyanobacteria, transparency and nutrients were the major indicators of water characteristics. The lake seems to be nitrogen-limited and cyanobacteria were negatively correlated with nitrogen levels, since the constantly dominant C. raciborskii is a superior competitor for N. We suggest that the monitoring of nitrogen levels is fundamental to establish management strategies to avoid harmful algae blooms in this Atlantic Forest lake.

  20. Resilience and Restoration of Lakes

    Directory of Open Access Journals (Sweden)

    Stephen R. Carpenter

    1997-06-01

    Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

  1. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2001-01-01

    Full Text Available The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric deposition, however, is still providing a large and steady flux of nitrogen compounds (nitrate and ammonium which is causing increasing nitrogen saturation in forest ecosystems and increasing nitrate levels in rivers. Besides atmospheric deposition, an important factor controlling water acidification and recovery is the weathering of rocks and soils which may be influenced by climate warming. A further factor is the episodic deposition of Saharan calcareous dust which contributes significantly to base cation deposition. Keywords: trend, atmospheric deposition, nitrogen, stream water chemistry.

  2. Development of a GIS interface for WEPP Model application to Great Lakes forested watersheds

    Science.gov (United States)

    J. R. Frankenberger; S. Dun; D. C. Flanagan; J. Q. Wu; W. J. Elliot

    2011-01-01

    This presentation will highlight efforts on development of a new online WEPP GIS interface, targeted toward application in forested regions bordering the Great Lakes. The key components and algorithms of the online GIS system will be outlined. The general procedures used to provide input to the WEPP model and to display model output will be demonstrated.

  3. Evidence for migratory spawning behavior by morphologically distinct Cisco (Coregonus artedi) from a small inland lake

    Science.gov (United States)

    Ross, Alexander J.; Weidel, Brian C.; Leneker, Mellisa; Solomon, Christopher T.

    2017-01-01

    Conservation and management of rare fishes relies on managers having the most informed understanding of the underlying ecology of the species under investigation. Cisco (Coregonus artedi), a species of conservation concern, is a cold-water pelagic fish that is notoriously variable in morphometry and life history. Published reports indicate, at spawning time, Cisco in great lakes may migrate into or through large rivers, whereas those in small lakes move inshore. Nonetheless, during a sampling trip to Follensby Pond, a 393 ha lake in the Adirondack Mountains, New York, we observed gravid Cisco swimming over an outlet sill from a narrow shallow stream and into the lake. We opportunistically dip-netted a small subsample of 11 individuals entering the lake from the stream (three female, eight male) and compared them to fish captured between 2013 and 2015 with gillnets in the lake. Stream-captured Cisco were considerably larger than lake-captured individuals at a given age, had significantly larger asymptotic length, and were present only as mature individuals between age of 3 and age 5. These results could suggest either Cisco are migrating from a nearby lake to spawn in Follensby Pond, or that a distinct morphotype of Cisco from Follensby Pond migrates out to the stream and then back in at spawning time. Our results appear to complement a handful of other cases in which Cisco spawning migrations have been documented and to provide the first evidence for such behavior in a small inland lake.

  4. Long-term limnological research of the Bohemian Forest lakes and their recent status

    Czech Academy of Sciences Publication Activity Database

    Vrba, Jaroslav (ed.); Kopáček, Jiří; Fott, J.

    2000-01-01

    Roč. 4, č. 4 (2000), s. 7-28 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. Č. Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727; GA ČR GA206/00/0063; GA AV ČR KSK2005601 Subject RIV: DA - Hydrology ; Limnology

  5. Ecology and potential for fishery of the small barbs (Cyprinidae, Teleostei) of Lake Tana, Ethiopia

    NARCIS (Netherlands)

    Dejen, E.

    2003-01-01

    Lake Tana is by far the largest lake of Ethiopia and source of the Blue Nile. By feeding on zooplankton, small barbs (< 10 cm) occupy a central position in Lake Tana's ecosystem. Catching them could release pressure on the overexploited, unique species flock of large barbs (up to 100 cm).

  6. Evaluation of Sugar Maple Dieback in the Upper Great Lakes Region and Development of a Forest Health Youth Education Program

    Science.gov (United States)

    Bal, Tara L.

    2013-01-01

    Sugar Maple, "Acer saccharum" Marsh., is one of the most valuable trees in the northern hardwood forests. Severe dieback was recently reported by area foresters in the western Upper Great Lakes Region. Sugar Maple has had a history of dieback over the last 100 years throughout its range and different variables have been identified as…

  7. U.S. Forest Service Region 1 Lake Chemistry, NADP, and IMPROVE air quality data analysis

    Science.gov (United States)

    Jill Grenon; Mark Story

    2009-01-01

    This report was developed to address the need for comprehensive analysis of U.S. Forest Service (USFS) Region 1 air quality monitoring data. The monitoring data includes Phase 3 (long-term data) lakes, National Atmospheric Deposition Program (NADP), and Interagency Monitoring of Protected Visual Environments (IMPROVE). Annual and seasonal data for the periods of record...

  8. Microfossil sequences in Ilponlampi, a small lake in northern Russian Karelia

    Directory of Open Access Journals (Sweden)

    Huttunen, A.

    1994-12-01

    Full Text Available The Holocene history of Ilponlampi, a small lake situated in northwestern Russian Karelia, is presented based on pollen, diatom, charred particle and botanical macroremain analyses. Four 14-C dates for the sequence show that it reaches back almost to the beginning of the Holocene. The immigration of the various tree species took place somewhat earlier than further west. A natural acidification process is characteristic of the lake, which seems to have remained practically unaffected by any human influence.

  9. Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe.

    Science.gov (United States)

    Khansaritoreh, Elmira; Dulamsuren, Choimaa; Klinge, Michael; Ariunbaatar, Tumurbaatar; Bat-Enerel, Banzragch; Batsaikhan, Ganbaatar; Ganbaatar, Kherlenchimeg; Saindovdon, Davaadorj; Yeruult, Yolk; Tsogtbaatar, Jamsran; Tuya, Daramragchaa; Leuschner, Christoph; Hauck, Markus

    2017-09-01

    Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland-dominated forest-steppe area and small forest patches in a grassland-dominated area. We found increasing climate sensitivity and decreasing first-order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland-dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland-dominated area, the increase was much greater than in the forest-dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure. © 2017 John Wiley & Sons Ltd.

  10. Small-scale non-industrial private forest ownership in the United States: rationale and implications for forest management

    Science.gov (United States)

    Yaoqi Zhang; Daowei Zhang; John Schelhas

    2005-01-01

    The transaction cost approach is used to explain why small non-industrial private forest (NIPF) ownerships are increasing in the U.S. We argue that the number of small NIPF owners have increased because: 1) a significant amount of forestland is no longer used economically if primarily for timber production, but rather for non-timber forest products and environmental...

  11. Cell specific primary production and phagotrophy of phytoplankton in acidified lakes of Bohemian Forest

    Czech Academy of Sciences Publication Activity Database

    Znachor, Petr; Hrubý, P.

    2000-01-01

    Roč. 4, č. 4 (2000), s. 223-232 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. České Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727; GA MŠk FRV:140/1999; GA AV ČR KSK2005601 Subject RIV: DA - Hydrology ; Limnology

  12. Chemical composition and phosphorus fractionation of sediments in the Bohemian Forest lakes

    Czech Academy of Sciences Publication Activity Database

    Borovec, Jakub

    2000-01-01

    Roč. 4, č. 4 (2000), s. 179-184 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. Č. Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727; GA ČR GA206/00/0063 Grant - others:EU(XE) MOLAR:ENV4-CT95-0007; EU(XE) EMERGE:EVK1-CT-1999-00032 Institutional research plan: CEZ:AV0Z6017912; CEZ:MSM123100004 Subject RIV: CB - Analytical Chemistry, Separation

  13. Geochemical pathways and biological uptake of radium in small Canadian Shield lakes

    International Nuclear Information System (INIS)

    Hesslein, R.H.; Slavicek, E.

    1984-01-01

    The sediment-water interactions and biological uptake of 226 Ra are described for four small Canadian Shield lakes at the Experimental Lakes Area, Kenora, Ontario. A single addition of 226 Ra was made to each lake between 1970 and 1976. Approximately 90 percent of the added 226 Ra initially sorbed to the sediments. Outflow from the lakes showed losses of only 5-11 percent 226 Ra per year. Models are proposed for adsorption and outflow of 226 Ra from lakes. Biological uptake and long-term 226 Ra concentrations were measured in three species of macrophytes, crayfish, and five species of fish. Bioaccumulation ranged from 1100 to 5000 in macrophytes, 705 in crayfish, from 30 to 80 in large trout (Salvelinus namaycush), white sucker (Catostomus commersoni), and lake whitefish (Coregonus clupeaformis), and from 230 to 1200 in fathead minnows (Pimephales promelas), pearl dace (Semotilus margarita), and northern redbelly dace (Chrosomus eos). The concept of Ra/Ca ratio in organisms versus water and food is used to explain the differences in bioaccumulation. 226 Ra is discriminated against versus calcium by fish but favoured by macrophytes and crayfish

  14. Impact of water-level changes to aquatic vegetation in small oligotrophic lakes

    Directory of Open Access Journals (Sweden)

    Egert VANDEL

    2016-06-01

    Full Text Available This study demonstrates the effect of drastic water-level changes to the aquatic vegetation in three small oligotrophic lakes situated in Kurtna Kame Field in north-eastern Estonia. The area holds around 40 lakes in 30 km2 of which 18 lakes are under protection as Natura Habitat lakes (Natura 2000 network. The area is under a strong human impact as it is surrounded by oil shale mines, sand quarry, peat harvesting field etc. The most severe impact comes from the groundwater intake established in 1972 in the vicinity of three studied lakes. The exploitation of groundwater led to drastic water-level drops. In 1980s the water-level drops were measured to be up to 3 to 4 meters compared to the levels of 1946. Lake Martiska and Lake Kuradijärv were severely affected and only 29% and 45% of lake area respectively and 21% of initial volume remained. Both lakes were described as oligotrophic lakes before severe human impact and held characteristic macrophytes such as Isoëtes lacustris L., Sparganium angustifolium Michx and Lobelia dortmanna L. As the water level declined the lakes lost their rare characteristic species and can now be described more as a meso- or even eutrophic lakes. When the volume of groundwater abstraction decreased in the 1990s the water levels started to recover but did not reach the natural levels of pre-industrialized era. Also the vegetation did not show any signs of recovery. In 2012 the pumping rates increased again causing a new rapid decline in water levels which almost exceed the previous minimum levels. The water-level monitoring alongside with the macrophyte monitoring data gives us a good case study on how the long term abrupt water-level changes can affect the aquatic vegetation

  15. [Species composition, diversity and density of small fishes in two different habitats in Niushan Lake].

    Science.gov (United States)

    Ye, Shao-Wen; Li, Zhong-Jie; Cao, Wen-Xuan

    2007-07-01

    This paper studied the spatial distribution of small fishes in a shallow macrophytic lake, Niushan Lake in spring 2003, and its relations with habitat heterogeneity. Based on the macrophyte cover condition, distance from lake shore and water depth, two representative habitat types in the lake were selected. Habitat A was near the shore with dense submersed macrophyte, while habitat B was far from the shore with sparse submersed macrophyte. Small fishes were sampled quantitatively by block net (180 m2), and their densities within the net area were estimated by multiple mark-recapture or Zippin's removal method. The results showed that there were some differences in species composition, biodiversity measurement, and estimated density of small fishes between the two habitats: 1) the catches in habitat A consisted of 14 small fish species from 5 families, among which, benthopelagic species Rhodeus ocellatus, Paracheilognathus imberbis and Pseudorasbora parva were considered as dominant species, while those in habitat B consisted of 9 small fish species from 3 families, among which, bottom species Rhinogobius giurinus and Micropercops swinhonis were dominant; 2) the Bray-Curtis index between the two small fish communities was 0.222, reflecting their low structure similarity, and no significant difference was observed between their rank/ abundance distributions, both of which belonged to log series distribution; 3) the total density of 9 major species in habitat A was 8.71 ind x m(-2), while that of 5 major species in habitat B was only 3.54 ind x m(-2). The fact that the spatial distribution of the small fishes differed with habitats might be related to their habitat need for escaping predators, feeding, and breeding, and thus, aquatic macrophyte habitat should be of significance in the rational exploitation of small fish resources as well as the conservation of fish resource diversity.

  16. Algal Diet of Small-Bodied Crustacean Zooplankton in a Cyanobacteria-Dominated Eutrophic Lake.

    Directory of Open Access Journals (Sweden)

    Ilmar Tõnno

    Full Text Available Small-bodied cladocerans and cyclopoid copepods are becoming increasingly dominant over large crustacean zooplankton in eutrophic waters where they often coexist with cyanobacterial blooms. However, relatively little is known about their algal diet preferences. We studied grazing selectivity of small crustaceans (the cyclopoid copepods Mesocyclops leuckarti, Thermocyclops oithonoides, Cyclops kolensis, and the cladocerans Daphnia cucullata, Chydorus sphaericus, Bosmina spp. by liquid chromatographic analyses of phytoplankton marker pigments in the shallow, highly eutrophic Lake Võrtsjärv (Estonia during a seasonal cycle. Copepods (mainly C. kolensis preferably consumed cryptophytes (identified by the marker pigment alloxanthin in gut contents during colder periods, while they preferred small non-filamentous diatoms and green algae (identified mainly by diatoxanthin and lutein, respectively from May to September. All studied cladoceran species showed highest selectivity towards colonial cyanobacteria (identified by canthaxanthin. For small C. sphaericus, commonly occuring in the pelagic zone of eutrophic lakes, colonial cyanobacteria can be their major food source, supporting their coexistence with cyanobacterial blooms. Pigments characteristic of filamentous cyanobacteria and diatoms (zeaxanthin and fucoxanthin, respectively, algae dominating in Võrtsjärv, were also found in the grazers' diet but were generally avoided by the crustaceans commonly dominating the zooplankton assemblage. Together these results suggest that the co-occurring small-bodied cyclopoid and cladoceran species have markedly different algal diets and that the cladocera represent the main trophic link transferring cyanobacterial carbon to the food web in a highly eutrophic lake.

  17. Sediment transport and channel morphology of small, forested streams.

    Science.gov (United States)

    Marwan A. Hassan; Michael Church; Thomas E. Lisle; Francesco Brardinoni; Lee Benda; Gordon E. Grant

    2005-01-01

    This paper reviews sediment transport and channel morphology in small, forested streams in the Pacific Northwest region of North America to assess current knowledge of channel stability and morphology relevant to riparian management practices around small streams. Small channels are defined as ones in which morphology and hydraulics may be significantly influenced by...

  18. Small Boreal Lake Ecosystem Evolution under the Influence of Natural and Anthropogenic Factors: Results of Multidisciplinary Long-Term Study

    Directory of Open Access Journals (Sweden)

    Liudmila Shirokova

    2016-07-01

    Full Text Available Small aquatic ecosystems of the boreal zone are known to be most sensitive indicators of on-going environmental change as well as local anthropogenic pressure, while being highly vulnerable to external impacts. Compared to rather detailed knowledge of the evolution of large and small lakes in Scandinavia and Canada, and large lakes in Eurasia, highly abundant small boreal lakes of northwest Russia have received very little attention, although they may become important centers of attraction of growing rural population in the near future. Here we present the results of a multidisciplinary, multi-annual study of a small boreal humic lake of NW Russia. A shallow (3 m and a deep (16 m site of this lake were regularly sampled for a range of chemical and biological parameters. Average multi-daily, summer-time values of the epilimnion (upper oxygenated layer of the lake provided indications of possible trends in temperature, nutrients, and bacterio-plankton concentration that revealed the local pollution impact in the shallow zone and overall environmental trend in the deep sampling point of the lake. Organic phosphorus, nitrate, and lead were found to be most efficient tracers of local anthropogenic pollution, especially visible in the surface layer of the shallow site of the lake. Cycling of trace elements between the epilimnion and hypolimnion is tightly linked to dissolved organic matter speciation and size fractionation due to the dominance of organic and organo-ferric colloids. The capacity of lake self-purification depends on the ratio of primary productivity to mineralization of organic matter. This ratio remained >1 both during winter and summer periods, which suggests a high potential of lake recovery from the input of allochthonous dissolved organic matter and local anthropogenic pollution.

  19. Simulation of Lake Surface Heat Fluxes by the Canadian Small Lake Model: Offline Performance Assessment for Future Coupling with a Regional Climate Model

    Science.gov (United States)

    Pernica, P.; Guerrero, J. L.; MacKay, M.; Wheater, H. S.

    2014-12-01

    Lakes strongly influence local and regional climate especially in regions where they are abundant. Development of a lake model for the purpose of integration within a regional climate model is therefore a subject of scientific interest. Of particular importance are the heat flux predictions provided by the lake model since they function as key forcings in a fully coupled atmosphere-land-lake system. The first step towards a coupled model is to validate and characterize the accuracy of the lake model over a range of conditions and to identify limitations. In this work, validation results from offline tests of the Canadian Small Lake Model; a deterministic, computationally efficient, 1D integral model, are presented. Heat fluxes (sensible and latent) and surface water temperatures simulated by the model are compared with in situ observations from two lakes; Landing Lake (NWT, Canada) and L239 (ELA, Canada) for the 2007-2009 period. Sensitivity analysis is performed to identify key parameters important for heat flux predictions. The results demonstrate the ability of the 1-D lake model to reproduce both diurnal and seasonal variations in heat fluxes and surface temperatures for the open water period. These results, in context of regional climate modelling are also discussed.

  20. Limnological characteristics of 56 lakes in the Central Canadian Arctic Treeline Region

    Directory of Open Access Journals (Sweden)

    John P. SMOL

    2003-02-01

    Full Text Available Measured environmental variables from 56 lakes across the Central Canadian Treeline Region exhibited clear limnological differences among subpolar ecozones, reflecting strong latitudinal changes in biome characteristics (e.g. vegetation, permafrost, climate. Principal Components Analysis (PCA clearly separated forested sites from tundra sites based on distinct differences in limnological characteristics. Increases in major ions and related variables (e.g. dissolved inorganic carbon, DIC were higher in boreal forest sites in comparison to arctic tundra sites. The higher values recorded in the boreal forest lakes may be indirectly related to differences in climatic factors in these zones, such as the degree of permafrost development, higher precipitation and runoff, duration of ice-cover on the lakes, and thicker and better soil development. Similar to trends observed in DIC, substantially higher values for dissolved organic carbon (DOC were measured in boreal forest lakes than in arctic tundra lakes. This was likely due to higher amounts of catchment-derived DOC entering the lakes from coniferous leaf litter sources. Relative to arctic tundra lakes, boreal forest lakes had higher nutrient concentrations, particularly total nitrogen (TN, likely due to warmer conditions, a longer growing season, and higher precipitation, which would enhance nutrient cycling and primary productivity. Results suggest that modern aquatic environments at opposite sides of the central Canadian arctic treeline (i.e. boreal forest and arctic tundra exhibit distinct differences in water chemistry and physical conditions. These limnological trends may provide important information on possible future changes with additional warming.

  1. The Bonobo Pan paniscus (Mammalia: Primates: Hominidae nesting patterns and forest canopy layers in the Lake Tumba forests and Salonga National Park, Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Bila-Isia Inogwabini

    2015-10-01

    Full Text Available The description and differentiation of habitat types is a major concern in ecology.  This study examined relationships between Bonobo Pan paniscus nesting patterns and forest structure in the Lake Tumba Swampy Forests. Data on presence of fresh Bonobo nests, canopy cover, canopy structure, tree densities and tree basal areas were collected systematically along 134 transects at 400m and 800m intervals, and the leaf-covered area (LCA was calculated for each of seven forest types. I observed a significant correlation between bonobo nests and mixed mature forest/closed understory forest type (r=-0.730, df = 21, p <0.05, but not mixed mature forest/open understory, old secondary forest and young secondary forest.  Basal areas of non-nesting trees along transects did not differ significantly from those in sites where bonobos nested.  Higher LCA (55% and 55% occurred in nesting sites when compared with non-nesting sites (39% and 42% at elevations 4–8 m and 8–16 m above the soil.  There was greater leaf cover in the understorey at sites where bonobos did not nest, while there was greater leaf cover in the mid-storey at sites where bonobos did nest.  

  2. Detecting Precontact Anthropogenic Microtopographic Features in a Forested Landscape with Lidar: A Case Study from the Upper Great Lakes Region, AD 1000-1600.

    Science.gov (United States)

    Howey, Meghan C L; Sullivan, Franklin B; Tallant, Jason; Kopple, Robert Vande; Palace, Michael W

    2016-01-01

    Forested settings present challenges for understanding the full extent of past human landscape modifications. Field-based archaeological reconnaissance in forests is low-efficiency and most remote sensing techniques are of limited utility, and together, this means many past sites and features in forests are unknown. Archaeologists have increasingly used light detection and ranging (lidar), a remote sensing tool that uses pulses of light to measure reflecting surfaces at high spatial resolution, to address these limitations. Archaeology studies using lidar have made significant progress identifying permanent structures built by large-scale complex agriculturalist societies. Largely unaccounted for, however, are numerous small and more practical modifications of landscapes by smaller-scale societies. Here we show these may also be detectable with lidar by identifying remnants of food storage pits (cache pits) created by mobile hunter-gatherers in the upper Great Lakes during Late Precontact (ca. AD 1000-1600) that now only exist as subtle microtopographic features. Years of intensive field survey identified 69 cache pit groups between two inland lakes in northern Michigan, almost all of which were located within ~500 m of a lakeshore. Applying a novel series of image processing techniques and statistical analyses to a high spatial resolution DTM we created from commercial-grade lidar, our detection routine identified 139 high potential cache pit clusters. These included most of the previously known clusters as well as several unknown clusters located >1500 m from either lakeshore, much further from lakeshores than all previously identified cultural sites. Food storage is understood to have emerged regionally as a risk-buffering strategy after AD 1000 but our results indicate the current record of hunter-gatherer cache pit food storage is markedly incomplete and this practice and its associated impact on the landscape may be greater than anticipated. Our study also

  3. Business Management Practices for Small to Medium Sized Forest Products Firms

    OpenAIRE

    Espinoza, Omar Alejandro; Smith, Robert L. (Robert Lee), 1955 August 21-

    2015-01-01

    Provides the information required to start a small forest products company by discussing the U.S. forest products industry, business management, strategic planning, business plans, and management of human resources, marketing, operations, and finances. This project was supported by the Wood Education and Resource Center, Northeastern Area State and Private Forestry, Forest Service, U.S. Department of Agriculture, award number: 2010-DG-148.

  4. Computing Evaporation Using Meteorological Data for Hydrological Budget of Lake Wapalanne in NJ School of Conservation

    Science.gov (United States)

    Jordan, J. J.; Barrett, K. R.; Galster, J. C.; Ophori, D. U.; Flores, D.; Kelly, S. A.; Lutey, A. M.

    2011-12-01

    Lake Wapalanne is small manmade lake about 5.4 hectares in northwest New Jersey in the Highlands Physiographic province within permanently protected land. The lake's surrounding area consists of forested vegetation and is relatively unoccupied which minimizes human influence. The lake's small size, minimal external influence, geographic isolation, and protected status provide an optimal research environment to record meteorological data used in calculation of potential evaporation. Between July 7h and August 3rd meteorological data was collected from a professional weather station placed on an island directly in the center of Lake Wapalanne. The Vantage Pro2 weather station provided accurate readings of temperate, humidity, wind-speed and direction, precipitation, and atmospheric pressure. A bathometric survey of the lake was conducted to determine the surface area with variations in depth of the lake's water level. Using the collected weather station data, a rate of potential evaporation was determined with several evaporation equations. A quantified volume was then derived from the rate and surface area of the lake. Using small scale evaporation measurements of known volumes of water within small pans placed in the lake water and National Oceanic and Atmospheric Administration evaporation stations near the experiment site, a comparison and validation of the calculated potential evaporation accuracy and regional evaporation is achieved. This three year study is part of an ongoing NSF Research Experience for Undergraduates (REU) project that encompasses additional topics of lake research; see abstract from Kelly et al. AGU 2011 for more information on the lake's hydrologic budget. The results and methods of this study will be of use in future forecasting and baseline measurements of hydrologic budgets for lakes and reservoirs within regional proximity, which provide drinking water to over five million people in the State of New Jersey.

  5. Physical and chemical consequences of artificially deepened thermocline in a small humic lake - a paired whole-lake climate change experiment

    Science.gov (United States)

    Forsius, M.; Saloranta, T.; Arvola, L.; Salo, S.; Verta, M.; Ala-Opas, P.; Rask, M.; Vuorenmaa, J.

    2010-05-01

    Climate change with higher air temperatures and changes in cloud cover, radiation and wind speed alters the heat balance and stratification patterns of lakes. A paired whole-lake thermocline manipulation experiment of a small (0.047 km2) shallow dystrophic lake (Halsjärvi) was carried out in southern Finland. A thermodynamic model (MyLake) was used for both predicting the impacts of climate change scenarios and for determining the manipulation target of the experiment. The model simulations assuming several climate change scenarios indicated large increases in the whole-lake monthly mean temperature (+1.4-4.4 °C in April-October for the A2 scenario), and shortening of the length of the ice covered period by 56-89 days. The thermocline manipulation resulted in large changes in the thermodynamic properties of the lake, and those were rather well consistent with the simulated future increases in the heat content during the summer-autumn season. The manipulation also resulted in changes in the oxygen stratification, and the expansion of the oxic water layer increased the spatial extent of the sediment surface oxic-anoxic interfaces. The experiment also affected several other chemical constituents; concentrations of TotN, NH4 and organic carbon showed a statistically significant decrease, likely due to both unusual hydrological conditions during the experiment period and increased decomposition and sedimentation. Changes in mercury processes and in the aquatic food web were also introduced. In comparison with the results of a similar whole-lake manipulation experiment in a deep, oligotrophic, clear-watered lake in Norway, it is evident that shallow dystrophic lakes, common in the boreal region, are more sensitive to physical perturbations. This means that projected climate change may strongly modify their physical and chemical conditions in the future.

  6. Can small zooplankton mix lakes?

    OpenAIRE

    Simoncelli, S.; Thackeray, S.J.; Wain, D.J.

    2017-01-01

    The idea that living organisms may contribute to turbulence and mixing in lakes and oceans (biomixing) dates to the 1960s, but has attracted increasing attention in recent years. Recent modeling and experimental studies suggest that marine organisms can enhance turbulence as much as winds and tides in oceans, with an impact on mixing. However, other studies show opposite and contradictory results, precluding definitive conclusions regarding the potential importance of biomixing. For lakes, on...

  7. Differences in seed rain composition in small and large fragments in the northeast Brazilian Atlantic Forest.

    Science.gov (United States)

    Knörr, U C; Gottsberger, G

    2012-09-01

    Tropical forests are seriously threatened by fragmentation and habitat loss. The impact of fragment size and forest configuration on the composition of seed rain is insufficiently studied. For the present study, seed rain composition of small and large forest fragments (8-388 ha) was assessed in order to identify variations in seed abundance, species richness, seed size and dispersal mode. Seed rain was documented during a 1-year period in three large and four small Atlantic Forest fragments that are isolated by a sugarcane matrix. Total seed rain included 20,518 seeds of 149 species of trees, shrubs, palms, lianas and herbs. Most species and seeds were animal-dispersed. A significant difference in the proportion of seeds and species within different categories of seed size was found between small and large fragments. Small fragments received significantly more very small-sized seeds (1.5 cm) that were generally very rare, with only one species in small and eight in large fragments. We found a negative correlation between the inflow of small-sized seeds and the percentage of forest cover. Species richness was lower in small than in large fragments, but the difference was not very pronounced. Given our results, we propose changing plant species pools through logging, tree mortality and a high inflow of pioneer species and lianas, especially in small forest fragments and areas with low forest cover. Connecting forest fragments through corridors and reforestation with local large-seeded tree species may facilitate the maintenance of species diversity. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  8. Euglossine bee communities in small forest fragments of the Atlantic Forest, Rio de Janeiro state, southeastern Brazil (Hymenoptera, Apidae

    Directory of Open Access Journals (Sweden)

    Willian Moura de Aguiar

    2012-06-01

    Full Text Available Euglossine bee communities in small forest fragments of the Atlantic Forest, Rio de Janeiro state, southeastern Brazil (Hymenoptera, Apidae. Euglossine bees are important pollinators in forests and agricultural areas. Although the structure of their communities is critically affected by anthropogenic disturbances, little is known about these bees in small forest fragments. The objectives of this study were to analyze the composition, abundance, and diversity of euglossine bee species in nine small fragments of different phytophysiognomies of the Atlantic Forest in southeastern Brazil, and to identify the environmental variables that may be related to the species composition of these communities. Males were sampled quarterly from May 2007 to May 2009 with aromatic traps containing methyl cinnamate, vanillin, eucalyptol, benzyl acetate, and methyl salicylate. A total of 1558 males, belonging to 10 species and three genera of Euglossina were collected. The richness ranged from five to seven species per fragment. Euglossa cordata, E. securigera, Eulaema nigrita e E. cingulata were common to all fragments studied. The diversity differed significantly among areas, ranging from H' = 1.04 to H' = 1.65. The precipitation, phytophysiognomy, and altitude had the highest relative importance over the species composition variation. The results presented in this study demonstrate that small forest fragments are able to support populations of euglossine bee species, most of which are widely distributed and reportedly tolerant to open and/or disturbed areas and suggest that the conservation of such areas is important, particularly in areas that are regenerating and in regions with agricultural matrices where these bees can act as important pollinators

  9. Climate Change Assessments for Lakes Region of Turkey

    Directory of Open Access Journals (Sweden)

    Ayten Erol

    2012-07-01

    Full Text Available Climate change is one of the most important challenges for forestry. Forests are known to be most efficient natural tools to ensure availability and quality of water in many regions. Besides, planning of forest resources towards water quality and quantity is essential in countries that are expected to face with more frequent drought periods in the next decades due to climate change. Watershed management concept has been supposed as the primary tool to plan natural resources in a more efficient and sustainable way by both academicians and practitioners to mitigate and adapt climate change. Forest cover among other land use types provides the best regulating mechanism to mitigate erosion, sedimentation, desertification, and pollution. In addition, climate change can potentially affect forest stand dynamics by influencing the availability of water resources. Therefore, the amount of forest cover in a watershed is an indicator of climate change mitigation and adaptation. Climate change is a concern and risk for the sustainability of water resources in Lakes Region of Turkey. The objective of this study is to make a comprehensive assessment in lake watersheds of the Lakes region considering the forest cover. For this purpose, the study gives a general view of trends in climatic parameters using Mann Kendall trend test. The results showed that Mann Kendall trend test for temperature and precipitation data is not enough to evaluate the magnitude of potential changes of climate in terms of forest cover. Understanding impacts of changes in temperature and precipitation on forest cover, runoff data should be evaluated with temperature and precipitation for watersheds of forest areas in Lakes Region.

  10. Spatial and temporal variability of greenhouse gas emissions from a small and shallow temperate lake

    Science.gov (United States)

    Praetzel, Leandra; Schmiedeskamp, Marcel; Broder, Tanja; Hüttemann, Caroline; Jansen, Laura; Metzelder, Ulrike; Wallis, Ronya; Knorr, Klaus-Holger; Blodau, Christian

    2017-04-01

    Small inland waters (spots" and "hot moments" that could contribute significantly to total emissions. To address this knowledge gap, we determined CO2 and CH4 emissions and dynamics to identify their controlling environmental factors in a polymictic small (1.4 ha) and shallow (max. depth approx. 1.5 m) crater lake ("Windsborn") in the Eifel uplands in south-west Germany. As Lake Windsborn has a small catchment area (8 ha) and no surficial inflows, it serves well as a model system for the identification of factors and processes controlling emissions. In 2015, 2016 and 2017 we measured CO2 and CH4 gas fluxes with different techniques across the sediment/water and water/atmosphere interface. Atmospheric exchange was measured using mini-chambers equipped with CO2 sensors and with an infra-red greenhouse gas analyzer for high temporal resolution flux measurements. Ebullition of CH4 was quantified with funnel traps. Sediment properties were examined using pore-water peepers. All measurements were carried out along a transect covering both littoral and central parts of the lake. Moreover, a weather station on a floating platform in the center of the lake recorded meteorological data as well as CO2 concentration in different depths of the water column. So far, Lake Windsborn seems to be a source for both CO2 and CH4 on an annual scale. CO2 emissions generally increased from spring to summer. Even though CO2 uptake could be observed during some periods in spring and fall, CO2 emissions in the summer exceeded the uptake. CO2 and CH4 emissions also appeared to be spatially variable between littoral areas and the inner lake. Shallow areas turned out to be "hot spots" of CO2 emissions whereas CH4 emissions were - against our expectations - highest in the center of the lake. Moreover, CH4 ebullition contributed substantially to total CH4 emissions. Our results show the importance of spatially and temporally highly resolved long-term measurements of greenhouse gas emissions and

  11. Small changes in climate can profoundly alter the dynamics and ecosystem services of tropical crater lakes.

    Science.gov (United States)

    Saulnier-Talbot, Émilie; Gregory-Eaves, Irene; Simpson, Kyle G; Efitre, Jackson; Nowlan, Tobias E; Taranu, Zofia E; Chapman, Lauren J

    2014-01-01

    African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have largely focused on the massive Great Rift Valley lakes. Our objective was to evaluate how recent climate change has altered the functioning and services of smaller tropical lakes, which are far more abundant on the landscape. Based on a paired analysis of 20 years of high-resolution water column data and a paleolimnological record from a small crater lake in western Uganda, we present evidence that even a modest warming of the air (∼0.9°C increase over 20 years) and changes in the timing and intensity of rainfall can have significant consequences on the dynamics of this common tropical lake type. For example, we observed a significant nonlinear increase (R(2) adj  = 0.23, e.d.f. = 7, pdeterioration of fish habitat and appears to have abated primary production; processes that may impair ecosystem services for a vulnerable human population. This study on a system representative of small tropical crater lakes highlights the far-reaching effects of global climatic change on tropical waters. Increased research efforts into tropical aquatic ecosystem health and the development of sound management practices are necessary in order to strengthen adaptive capabilities in tropical regions.

  12. Monitoring climate signal transfer into the varved lake sediments of Lake Czechowskie, Poland

    Science.gov (United States)

    Groß-Schmölders, Miriam; Ott, Florian; Brykała, Dariusz; Gierszewski, Piotr; Kaszubski, Michał; Kienel, Ulrike; Brauer, Achim

    2015-04-01

    In 2012 we started a monitoring program at Lake Czechowskie, Poland, because the lake comprises a long Holocene time series of calcite varves until recent times. The aim of the program is to understand how environmental and climatic conditions influence the hydrological conditions and, ultimately, the sediment deposition processes of the lake. Lake Czechowskie is located in the north of Poland in the Pomeranian Lake District and is part of the national park Tuchola Forest. The landscape and the lake is formed by the glacier retreat after the last glaciation (Weichselian). Lake Czechowskie is a typical hardwater lake and has a length of 1.4 km, an average width of 600 m and a lake surface area of ca 4 km. The maximum depth of 32 m is reached in a rather small hollow in the eastern part of the lake. Two different types of sediment traps provide sediment samples with monthly resolution from different water depths (12m, 26m). In addition, hydrological data including water temperature in different depths, water inflow, throughflow and outflow and the depth of visibility are measured. These data allow to describe strength and duration of lake mixing in spring and autumn and its influence on sedimentation. The sediment samples were analyzed with respect to their dry weight (used to calculate mean daily sediment flux), their inorganic and organic carbon contents, the stable C- and O-isotopes of organic matter and calcite as well as N-isotopes of organic matter. For selected samples dominant diatom taxa are determined. Our first results demonstrate the strong influence of the long winter with ice cover until April in 2013 on the sedimentation. A rapid warming in only 9 days starting on April 9th from -0,3 C° to 15,2 C° resulted in fast ice break-up and a short but intensive lake mixing. In consequence of this short mixing period a strong algal bloom especially of Fragilaria and Crysophycea commenced in April and had its maximum in May. This bloom further induced biogenic

  13. Analysis of nitrogen saturation potential in Rocky Mountain tundra and forest: implications for aquatic systems

    Science.gov (United States)

    Baron, Jill S.; Ojima, Dennis S.; Holland, Elisabeth A.; Parton, William J.

    1994-01-01

    We employed grass and forest versions of the CENTURY model under a range of N deposition values (0.02–1.60 g N m−2 y−1) to explore the possibility that high observed lake and stream N was due to terrestrial N saturation of alpine tundra and subalpine forest in Loch Vale Watershed, Rocky Mountain National Park, Colorado. Model results suggest that N is limiting to subalpine forest productivity, but that excess leachate from alpine tundra is sufficient to account for the current observed stream N. Tundra leachate, combined with N leached from exposed rock surfaces, produce high N loads in aquatic ecosystems above treeline in the Colorado Front Range. A combination of terrestrial leaching, large N inputs from snowmelt, high watershed gradients, rapid hydrologic flushing and lake turnover times, and possibly other nutrient limitations of aquatic organisms constrain high elevation lakes and streams from assimilating even small increases in atmospheric N. CENTURY model simulations further suggest that, while increased N deposition will worsen the situation, nitrogen saturation is an ongoing phenomenon.

  14. Temporal variation of phytoplankton in a small tropical crater lake, Costa Rica

    Directory of Open Access Journals (Sweden)

    Gerardo Umaña-Villalobos

    2010-12-01

    Full Text Available The temporal variation in lake’s phytoplankton is important to understand its general biodiversity. For tropical lakes, it has been hypothesized that they follow a similar pattern as temperate ones, on a much accelerated pace; nevertheless, few case studies have tried to elucidate this. Most studies in Costa Rica have used a monthly sampling scheme and failed in showing the expected changes. In this study, the phytoplankton of the small Barvas’s crater lake was followed for more than three years, first with monthly and later with weekly samplings, that covered almost two years. Additional information on temperature and oxygen vertical profiles was obtained on a monthly basis, and surface temperature was measured during weekly samplings around noon. Results showed that in spite of its shallow condition (max. depth: 7m and low surface temperature (11 to 19°C, the lake stratifies at least for brief periods. The phytoplankton showed both, rapid change periods, and prolonged ones of relative stasis. The plankton composition fluctuated between three main phases, one characterized by the abundance of small sized desmids (Staurastrum paradoxum, Cosmarium asphaerosporum, a second phase dominated by equally small cryptomonads (Chryptochrysis minor, Chroomonas sp. and a third phase dominated by the green alga Eutetramorus tetrasporus. Although data evidenced that monthly sampling could miss short term events, the temporal variation did not follow the typical dry and rainy seasons of the region, or any particular annual pattern. Year to year variation was high. As this small lake is located at the summit of Barva Volcano and receives the influence from both the Caribbean and the Pacific weather, seasonality at the lake is not clearly defined as in the rest of the country and short term variations in the local weather might have a stronger effect than broad seasonal trends. The occurrence of this short term changes in the phytoplankton of small tropical

  15. The consequences of changes in forest land cover in the Alpine and Jurassic massifs on the physico-chemical status of deep lake waters

    Directory of Open Access Journals (Sweden)

    Rachid Nedjai

    2012-02-01

    Full Text Available The issue of acidification in lake waters has been the topic of numerous scientific studies in northern Europe and North America. In recent years, interest in the topic has spread to southern Europe and Asia because similar symptoms have been observed (drop in pH and in redox potential, generally accompanied by oxygen depletion. All the scientific work on the issue has concluded that the phenomenon is general and affects, to different degrees, lakes located at low to medium altitudes in mountains (the Vosges mountains and more recently the Jura mountains, in France. The difference in degree is often interpreted as the result of different combinations from three sources, namely acid rain, direct discharges of pollutants and the spread of forests (essentially conifer species. The first two sources have been confirmed, but the third is less perceptible due to slow progression of the phenomenon.Analysis and modelling of changes in land cover in the Hérisson river basin in the Jura mountains (largely carbonated soils confirmed the direct impact of the forest cover on the physico-chemical quality of lake waters, in particular at the deeper levels (hypolimnion over the past 30 years. The impact is reinforced by the considerable presence of peat zones around the lakes which, during high-water periods, contribute large quantities of dissolved, particulate organic matter.The goal of this work is to show the direct impact of the increasing forest cover observed on the Jurassic plateaus, caused by a considerable reduction in farming activity over the past 30 years. This work focuses on an analysis of land cover (vegetation, using four satellite images spanning the period from 1975 to 2006, and calls on hydrogeochemical modelling (WARMF to evaluate changes in the physico-chemical quality, i.e. acidification, of deep lake waters. This first step is followed by a predictive phase prior to measuring the intensity of the physico-chemical changes (pH and redox

  16. Composition and seasonal phenology of a nonindigenous root-feeding weevil (Coleoptera: Curculionidae) complex in northern hardwood forests in the Great Lakes Region

    Science.gov (United States)

    R. A. Pinski; W. J. Mattson; K. F. Raffa

    2005-01-01

    Phyllobius oblongus (L.), Polydrusus sericeus (Schaller), and Sciaphilus asperatus (Bonsdorff) comprise a complex of nonindigenous root-feeding weevils in northern hardwood forests of the Great Lakes region. Little is known about their detailed biology, seasonality, relative abundance, and distribution patterns....

  17. Small changes in climate can profoundly alter the dynamics and ecosystem services of tropical crater lakes.

    Directory of Open Access Journals (Sweden)

    Émilie Saulnier-Talbot

    Full Text Available African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have largely focused on the massive Great Rift Valley lakes. Our objective was to evaluate how recent climate change has altered the functioning and services of smaller tropical lakes, which are far more abundant on the landscape. Based on a paired analysis of 20 years of high-resolution water column data and a paleolimnological record from a small crater lake in western Uganda, we present evidence that even a modest warming of the air (∼0.9°C increase over 20 years and changes in the timing and intensity of rainfall can have significant consequences on the dynamics of this common tropical lake type. For example, we observed a significant nonlinear increase (R(2 adj  = 0.23, e.d.f. = 7, p<0.0001 in thermal stability over the past 20 years. This resulted in the expansion of anoxic waters and consequent deterioration of fish habitat and appears to have abated primary production; processes that may impair ecosystem services for a vulnerable human population. This study on a system representative of small tropical crater lakes highlights the far-reaching effects of global climatic change on tropical waters. Increased research efforts into tropical aquatic ecosystem health and the development of sound management practices are necessary in order to strengthen adaptive capabilities in tropical regions.

  18. Changes to zooplankton community structure following colonization of a small lake by Leptodora kindti

    Science.gov (United States)

    McNaught, A.S.; Kiesling, R.L.; Ghadouani, A.

    2004-01-01

    The predaceous cladoceran Leptodora kindti (Focke) became established in Third Sister Lake, Michigan, after individuals escaped from experimental enclosures in 1987. By 1988, the Leptodora population exhibited seasonal dynamics characteristic of natural populations. The maximum seasonal abundance of Leptodora increased to 85 individuals m-3 3 yr following the introduction. After the appearance of Leptodora, small-bodied cladocerans (Ceriodaphnia and Bosmina) virtually disappeared from the lake. There were strong seasonal shifts in the dominance patterns of both cladocerans and copepods, and Daphnia species diversity increased. Results from this unplanned introduction suggest that invertebrate predators can have a rapid and lasting effect on prey populations, even in the presence of planktivorous fish. Small-scale (<20 km) geographic barriers might be as important as large-scale barriers to dispersal of planktonic animals.

  19. Evaluation of groundwater discharge into small lakes based on the temporal distribution of radon-222

    Science.gov (United States)

    Dimova, N.T.; Burnett, W.C.

    2011-01-01

    In order to evaluate groundwater discharge into small lakes we constructed a model that is based on the budget of 222Rn (radon t1/2 5 3.8 d) as a tracer. The main assumptions in our model are that the lake's waters are wellmixed horizontally and vertically; the only significant 222Rn source is via groundwater discharge; and the only losses are due to decay and atmospheric evasion. In order to evaluate the groundwater-derived 222Rn flux, we monitored the 222Rn concentration in lake water over periods long enough (usually 1-3 d) to observe changes likely caused by variations in atmospheric exchange (primarily a function of wind speed and temperature). We then attempt to reproduce the observed record by accounting for decay and atmospheric losses and by estimating the total 222Rn input flux using an iterative approach. Our methodology was tested in two lakes in central Florida: one of which is thought to have significant groundwater inputs (Lake Haines) and another that is known not to have any groundwater inflows but requires daily groundwater augmentation from a deep aquifer (Round Lake). Model results were consistent with independent seepage meter data at both Lake Haines (positive seepage of ??? 1.6 ?? 104 m3 d-1 in Mar 2008) and at Round Lake (no net groundwater seepage). ?? 2011, by the American Society of Limnology and Oceanography, Inc.

  20. 78 FR 69363 - Lake Tahoe Basin Management Unit, California, Heavenly Mountain Resort Epic Discovery Project

    Science.gov (United States)

    2013-11-19

    ... DEPARTMENT OF AGRICULTURE Forest Service Lake Tahoe Basin Management Unit, California, Heavenly Mountain Resort Epic Discovery Project AGENCY: Lake Tahoe Basin Management Unit, Forest Service, USDA...: The Epic Discovery Project is intended to enhance summer activities in response to the USDA Forest...

  1. Development of a spatial forest data base for the eastern boreal forest region of Ontario. Forest fragmentation and biodiversity project technical report No. 14

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    In 1991, a spatial forest database over large regions of Ontario was initiated as the basis for research into forest fragmentation and biodiversity using data generated from the digital analysis of LANDSAT thematic mapper satellite data integrated into a geographic information system (GIS). The project was later extended into the eastern segment of the Boreal forest system. This report describes preparation of the spatial forest data base over the eastern Boreal Forest Region that extends from the northern boundary of the Great Lakes-St. Lawrence Forest Region and the southern margin of the James Bay Lowland, between the Ontario-Quebec border and a point west of Michipicoten on Lake Superior. The report describes the methodology used to produce the data base and results, including mapping of water, dense and sparse conifer forest, mixed forest, dense and sparse deciduous forest, poorly vegetated areas, recent cutovers of less than 10 years, old cutovers and burns, recent burns of less than 10 years, wetlands, bedrock outcrops, agriculture, built-up areas, and mine tailings.

  2. Lake and bulk sampling chemistry, NADP, and IMPROVE air quality data analysis on the Bridger-Teton National Forest (USFS Region 4)

    Science.gov (United States)

    Jill Grenon; Terry Svalberg; Ted Porwoll; Mark Story

    2010-01-01

    Air quality monitoring data from several programs in and around the Bridger-Teton (B-T) National Forest - National Atmospheric Deposition Program (NADP), longterm lake monitoring, long-term bulk precipitation monitoring (both snow and rain), and Interagency Monitoring of Protected Visual Environments (IMPROVE) - were analyzed in this report. Trends were analyzed using...

  3. Timber resource statistics for all forest land, except national forests, in eastern Oregon.

    Science.gov (United States)

    Donald R. Gedney; Patricia M. Bassett; Mary A. Mei

    1989-01-01

    This report summarizes a 1987 timber resource inventory of all forest land, except National Forests, in the 17 counties (Baker, Crook, Deschutes, Gilliam, Grant, Harney, Jefferson, Klamath, Lake, Malheur, Morrow, Sherman, Umatilla, Union, Wallowa, Wasco, and Wheeler Counties) in eastern Oregon. Detailed tables of forest area, timber volume, growth, mortality, and...

  4. Spatial distribution of small-leaved forests in Kuznetskaya depression

    Directory of Open Access Journals (Sweden)

    A. F. Gulyaeva

    2016-03-01

    Full Text Available The article is devoted to the spatial distribution of small-leaved forests in Kuznetskaya depression where they are forest component of zonal forest-steppe vegetation. Two levels of spatial organization were determined. According to mesorelief communities of different associations are organized into topo-ecological series. These series differ by length and set of communities. On higher level spatial distribution is controlled by climate and reflects zonal structure. Central part of the depression is occupied by Artemisio–Betuletum communities in combination with communities of Calamagrostio–Betuletum which occur in more humid habitats. Near the eastern edge of the depres­sion forest vegetation is represented by combination of Trollio–Populetum and Campanulo–Betuletum communities where the first one is more typical for the plain conditions and second one – for the mountainous environment. In south­ern part of the depression communities of Campanulo–Betuletum are widespread in combination with Saussureo–Populetum communities which localized on higher well-moisturized slopes. In north-western part syntaxonomical diversity drops down to one association – Primulo–Betuletum, and communities of Carici–Betuletum association occur across the whole depression in lowest relief positions. Climatically it is possible to distinguish two belts – forest-steppe and subtaiga. Forest-steppe is represented by two types – typical plain forest-steppe in north-western part and submountainous forest-steppe in the central part of depression. Subtaiga belt in the depression is developed on eastern edge, but in western part it exists only on mountain slopes.

  5. Informing the improvement of forest products durability using small angle neutron scattering

    Science.gov (United States)

    Nayomi Plaza Rodriguez; Sai Venkatesh Pingali; Shuo Qian; William T. Heller; Joseph E. Jakes

    2016-01-01

    A better understanding of how wood nanostructure swells with moisture is needed to accelerate the development of forest products with enhanced moisture durability. Despite its suitability to study nanostructures, small angle neutron scattering (SANS) remains an underutilized tool in forest products research. Nanoscale moisture-induced structural changes in intact and...

  6. Community occupancy responses of small mammals to restoration treatments in ponderosa pine forests, northern Arizona, USA.

    Science.gov (United States)

    Kalies, E L; Dickson, B G; Chambers, C L; Covington, W W

    2012-01-01

    In western North American conifer forests, wildfires are increasing in frequency and severity due to heavy fuel loads that have accumulated after a century of fire suppression. Forest restoration treatments (e.g., thinning and/or burning) are being designed and implemented at large spatial and temporal scales in an effort to reduce fire risk and restore forest structure and function. In ponderosa pine (Pinus ponderosa) forests, predominantly open forest structure and a frequent, low-severity fire regime constituted the evolutionary environment for wildlife that persisted for thousands of years. Small mammals are important in forest ecosystems as prey and in affecting primary production and decomposition. During 2006-2009, we trapped eight species of small mammals at 294 sites in northern Arizona and used occupancy modeling to determine community responses to thinning and habitat features. The most important covariates in predicting small mammal occupancy were understory vegetation cover, large snags, and treatment. Our analysis identified two generalist species found at relatively high occupancy rates across all sites, four open-forest species that responded positively to treatment, and two dense-forest species that responded negatively to treatment unless specific habitat features were retained. Our results indicate that all eight small mammal species can benefit from restoration treatments, particularly if aspects of their evolutionary environment (e.g., large trees, snags, woody debris) are restored. The occupancy modeling approach we used resulted in precise species-level estimates of occupancy in response to habitat attributes for a greater number of small mammal species than in other comparable studies. We recommend our approach for other studies faced with high variability and broad spatial and temporal scales in assessing impacts of treatments or habitat alteration on wildlife species. Moreover, since forest planning efforts are increasingly focusing on

  7. Distributions, Sources, and Backward Trajectories of Atmospheric Polycyclic Aromatic Hydrocarbons at Lake Small Baiyangdian, Northern China

    Directory of Open Access Journals (Sweden)

    Ning Qin

    2012-01-01

    Full Text Available Air samples were collected seasonally at Lake Small Baiyangdian, a shallow lake in northern China, between October 2007 and September 2008. Gas phase, particulate phase and dust fall concentrations of polycyclic aromatic hydrocarbons (PAHs were measured using a gas chromatograph-mass spectrometer (GC-MS. The distribution and partitioning of atmospheric PAHs were studied, and the major sources were identified; the backward trajectories of air masses starting from the center of Lake Small Baiyangdian were calculated for the entire year. The following results were obtained: (1 The total concentration of 16 priority controlled PAHs (PAH16 in the gas phase was 417.2±299.8 ng·m−3, in the particulate phase was 150.9±99.2 ng·m−3, and in dust fall was 6930.2±3206.5 ng·g−1. (2 Vehicle emission, coal combustion, and biomass combustion were the major sources in the Small Baiyangdian atmosphere and accounted for 28.9%, 45.1% and 26.0% of the total PAHs, respectively. (3 Winter was dominated by relatively greater PAHs polluted northwesterly air mass pathways. Summer showed a dominant relatively clean southern pathway, whereas the trajectories in autumn and spring might be associated with high pollution from Shanxi or Henan province.

  8. Impacts of nutrients and pesticides from small- and large-scale agriculture on the water quality of Lake Ziway, Ethiopia

    NARCIS (Netherlands)

    Teklu, Berhan M.; Hailu, Amare; Wiegant, Daniel A.; Scholten, Bernice S.; Brink, van den Paul J.

    2018-01-01

    The area around Lake Ziway in Ethiopia is going through a major agricultural transformation with both small-scale farmers and large horticultural companies using pesticides and fertilisers at an increased rate. To be able to understand how this influences the water quality of Lake Ziway, water

  9. Impacts of nutrients and pesticides from small- and large-scale agriculture on the water quality of Lake Ziway, Ethiopia

    NARCIS (Netherlands)

    Teklu, Berhan M.; Hailu, Amare; Wiegant, Daniel A.; Scholten, Bernice S.; Brink, van den Paul J.

    2016-01-01

    The area around Lake Ziway in Ethiopia is going through a major agricultural transformation with both small-scale farmers and large horticultural companies using pesticides and fertilisers at an increased rate. To be able to understand how this influences the water quality of Lake Ziway, water

  10. MERGANSER - A Predictive Model of Mercury in Fish and Loons in New England Lakes

    Science.gov (United States)

    Moore, R. B.; Shanley, J. B.; Smith, R. A.; Miller, E. K.; Simcox, A.; Kamman, N. C.; Nacci, D. E.; Robinson, K. W.; Johnston, J. M.; Hughes, M.; Johnston, C. M.; Williams, K.; Graham, J.; King, S.

    2010-12-01

    MERGANSER (MERcury Geo-spatial AssessmeNtS for the New England Region) is an empirical least squares multiple regression model using atmospheric deposition of mercury (Hg) and readily obtainable lake and watershed features to predict fish and common loon Hg in New England lakes. We modeled lakes larger than 8 ha and with drainage area completely within the USA (4404 lakes), using 3827 fish (12 species) and loon Hg values from 420 lakes. MERGANSER predictor variables included Hg deposition, watershed alkalinity, percent wetlands, percent forest canopy, percent agriculture, drainage area, population, mean annual temperature and watershed slope. The model returns fish tissue or loon blood Hg for user-entered species and length. MERGANSER explained 63% of the variance in fish fillet and loon Hg concentrations. MERGANSER predicted that 32-cm small mouth bass had a median Hg concentration of 0.53 µg g-1 and exceeded EPA’s maximum contaminant level (MCL) of 0.3 µg/g Hg in 90% of New England lakes. Common loon had a median Hg concentration of 1.07 µg g-1 and was in the moderate or higher risk category of >1 µg/g Hg in 58% of New England lakes.

  11. Using traditional ecological knowledge as a basis for targeted forest inventory: paper birch (Betula papyrifera) in the US Great Lakes Region

    Science.gov (United States)

    Marla R. Emery; Alexandra Wrobel; Mark H. Hansen; Michael Dockry; W. Keith Moser; Kekek Jason Stark; Jonathan H. Gilbert

    2014-01-01

    Traditional ecological knowledge (TEK) has been proposed as a basis for enhanced understanding of ecological systems and their management. TEK also can contribute to targeted inventories of resources not included in standard mensuration. We discuss the results of a cooperative effort between the Great Lakes Indian Fish and Wildlife Commission (GLIFWC) and USDA Forest...

  12. Properties of soils and tree-wood tissue across a Lake States sulfate-deposition gradient. Forest Service resource bulletin

    International Nuclear Information System (INIS)

    Ohmann, L.F.; Grigal, D.F.

    1991-01-01

    There is general concern that atmospheric pollutants may be affecting the health of forests in the USA. The hypotheses tested were that the wet sulfate deposition gradient across the Lake States: (1) is reflected in the amount of accumulated sulfur in the forest floor-soil system and tree woody tissue and (2) is related to differences in tree radial increment. The authors present the properties of the soil and tree woody tissue (mostly chemical) on the study plots. Knowledge of the properties of soil and woody tree tissue is needed for understanding and interpreting relations between sulfate deposition, sulfur accumulation in the ecosystem, soil and tree chemistry, and tree growth and climatic variation. The report provides a summary of those data for study, analysis, and interpretation

  13. 36 CFR 7.69 - Ross Lake National Recreation Area.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Ross Lake National Recreation... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.69 Ross Lake National Recreation Area... snowmobiles the following locations within the Ross Lake National Recreation Area: (1) State Highway 20, that...

  14. Quantitative vegetation reconstruction from pollen analysis and historical inventory data around a Danish small forest hollow

    DEFF Research Database (Denmark)

    Overballe-Petersen, Mette V; Nielsen, Anne Birgitte; Bradshaw, Richard H.W.

    2013-01-01

    of the pollen record? Location Denmark. The Gribskov-Ostrup small forest hollow (56°N, 12°20' E, 44 m a.s.l.) in the forest of Gribskov, eastern Denmark. Methods Pollen analysis was carried out on a small forest hollow, and LRA used to derive pollen-based quantitative estimates of past vegetation. Historical......Questions Can the model performance of the landscape reconstruction algorithm (LRA) for small forest hollows be validated through comparison to inventory-based vegetation reconstructions from the last 150 yrs? Does the application of LRA and the comparison to historical data enhance interpretation...... forest inventory data and maps were used to reconstruct the vegetation within three different circles around the hollow (20, 50 and 200 m ring widths) for five time periods during the last 150 yrs. The results of the two approaches were compared in order to evaluate model performance, and the LRA...

  15. The Stream-Catchment (StreamCat) and Lake-Catchment ...

    Science.gov (United States)

    Background/Question/MethodsLake and stream conditions respond to both natural and human-related landscape features. Characterizing these features within contributing areas (i.e., delineated watersheds) of streams and lakes could improve our understanding of how biological conditions vary spatially and improve the use, management, and restoration of these aquatic resources. However, the specialized geospatial techniques required to define and characterize stream and lake watersheds has limited their widespread use in both scientific and management efforts at large spatial scales. We developed the StreamCat and LakeCat Datasets to model, predict, and map the probable biological conditions of streams and lakes across the conterminous US (CONUS). Both StreamCat and LakeCat contain watershed-level characterizations of several hundred natural (e.g., soils, geology, climate, and land cover) and anthropogenic (e.g., urbanization, agriculture, mining, and forest management) landscape features for ca. 2.6 million stream segments and 376,000 lakes across the CONUS, respectively. These datasets can be paired with field samples to provide independent variables for modeling and other analyses. We paired 1,380 stream and 1,073 lake samples from the USEPAs National Aquatic Resource Surveys with StreamCat and LakeCat and used random forest (RF) to model and then map an invertebrate condition index and chlorophyll a concentration, respectively. Results/ConclusionsThe invertebrate

  16. Thinning effects on spotted owl prey and other forest-dwelling small mammals

    Science.gov (United States)

    Todd M. Willson; Eric D. Forsman

    2013-01-01

    Th inning has been promoted as a method for accelerating the development of late-seral habitat and improving the overall health and function of young forests in the Pacifi c Northwest. Population studies have shown early and positive responses to thinning by some small forest-floor mammals (primarily mice, terrestrial voles, and shrews). However, thinning reduces the...

  17. Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

    Science.gov (United States)

    Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

    2006-01-01

    We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

  18. Eutrophication potential of Payette Lake, Idaho

    Science.gov (United States)

    Woods, Paul F.

    1997-01-01

    Payette Lake was studied during water years 1995-96 to determine the 20.5-square-kilometer lake's assimilative capacity for nutrients and, thus, its eutrophication potential. The study included quantification of hydrologic and nutrient budgets, characterization of water quality in the limnetic and littoral zones, development of an empirical nutrient load/lake response model, and estimation of the limnological effects of a large-scale forest fire in the lake's 373-square-kilometer watershed during the autumn of 1994. Streamflow from the North Fork Payette River, the lake's primary tributary, delivered about 73 percent of the lake's inflow over the 2 years. Outflow from the lake, measured since 1908, was 128 and 148 percent of the long-term average in 1995 and 1996, respectively. The larger volumes of outflow reduced the long-term average water-

  19. Catchment-fed cyanobacterial blooms in brownified temperate lakes

    Science.gov (United States)

    Senar, O.; Creed, I. F.

    2017-12-01

    One of the most significant impacts of global atmospheric change is the alteration of hydrological regimes and the associated disruption of hydrological connectivity within watersheds. We show how changes in the frequency, magnitude, and duration of hydrological connectivity and disconnectivity is compromising the capacity of forest soils to store organic carbon, and increasing its export to both aquatic and atmospheric systems. Increases in dissolved organic matter (DOM) loads from forested landscapes to aquatic systems and the shift of the DOM pool to a more refractory mixture of organic compounds, a process known as brownification, alters the physical and chemical characteristics of lake environments. Furthermore, by characterizing the stages of brownification (from low to high concentrations of refractory DOM), we show a shift in the limiting factors for phytoplankton growth from macronutrients (nitrogen -N- and phosphorus -P) to micronutrients (iron -Fe) and light availability. This shift is driven by the low concentrations of DOM supplying N and P in early stages of brownification, to the strong Fe-binding capacity of refractory DOM in brownified lakes. As lakes undergo brownification, cyanobacteria adapted to scavenge Fe from DOM-Fe complexes have a competitive advantage leading to the formation of cyanobacterial blooms. Our findings provide evidence that brownification is a driving force leading to cyanobacterial blooms in lakes on forested landscapes, with expected cascading consequences to lake food webs.

  20. Recovery of small pile burn scars in conifer forests of the Colorado Front Range

    Science.gov (United States)

    Charles C. Rhoades; Paula J. Fornwalt; Mark W. Paschke; Amber Shanklin; Jayne L. Jonas

    2015-01-01

    The ecological consequences of slash pile burning are a concern for land managers charged with maintaining forest soil productivity and native plant diversity. Fuel reduction and forest health management projects have created nearly 150,000 slash piles scheduled for burning on US Forest Service land in northern Colorado. The vast majority of these are small piles (

  1. Public perspectives of fire, fuels, and the Forest Service in the Great Lakes Region: a survey of citizen-agency communication and trust

    Science.gov (United States)

    Bruce A. Shindler; Eric Toman; Sarah M. McCaffrey

    2009-01-01

    Relative to the western United States, where fire and fuel management programs have received greater emphasis, few community-based studies have focused on the Great Lakes region. The present paper describes public opinion research from counties surrounding National Forests inWisconsin, Minnesota and Michigan. Survey data address citizen perspectives on (1) fuel...

  2. Numerical Modelling Approaches for Assessing Improvements to the Flow Circulation in a Small Lake

    Directory of Open Access Journals (Sweden)

    Cheng He

    2011-01-01

    Full Text Available Kamaniskeg Lake is a long, narrow, and deep small lake located in the northern part of Ontario, Canada. The goals of this paper were to examine various options to improve the water quality in the northern part of the lake by altering the local hydraulic flow conditions. Towards this end, a preliminary screening suggested that the flow circulation could be increased around a central island (Mask Island in the northern part of the lake by opening up an existing causeway connecting the mainland and central island. Three-dimensional (3D hydraulic and transport models were adopted in this paper to investigate the hydraulic conditions under various wind forces and causeway structures. The modelling results show that opening the causeway in a few places is unlikely to generate a large flow circulation around the central island. Full circulation only appears to be possible if the causeway is fully removed and a strong wind blows in a favourable direction. The possible reasons for existing water quality variations at the intake of a local WTP (water treatment plant are also explored in the paper.

  3. The operational efficiency of waterway transport of forest chips on Finland's Lake Saimaa

    Energy Technology Data Exchange (ETDEWEB)

    Karttunen, K.; Ranta, T. [Lappeenranta Univ. of Technology, LUT Savo Sustainable Technologies, Mikkeli (Finland); Vaatainen, K.; Asikainen, A. [The Finnish Forest Research Inst., Joensuu (Finland)], E-mail: kalle.karttunen@lut.fi

    2012-11-01

    New and cost-efficient methods for use in supply chains for energy wood should be found, to reach the targets of the renewable energy utilisation set by the European Union. The long-distance waterway transportation of forest fuels should be thoroughly investigated, especially in areas where the transport distance is long and waterways could provide a feasible method of conveying forest fuel. In comparison to transport of forest chips by truck, barge-based waterway transport shows a competitive advantage due to the larger loads and higher bulk density of chips it allows. The cost-efficiency of waterway transportation operations related to forest chips in Finland's Lake Saimaa region was studied using practical demonstrations and discrete-event simulation. The varying demand for fuel wood in three separate bio-power plants on the Saimaa lakeside (near the cities of Varkaus, Mikkeli, and Savonlinna) was addressed in several barge transportation scenarios. Finally, the economy of barge transportation was compared to the economy of truck transportation as a function of transportation distance and in terms of the annual performance of the transportation methods examined. The waterway supply chain of forest chips was cost-competitive to road transport by truck after 100-150 km. According to the simulation study, the most economical waterway transport options were based on fixed barge system and shift-independent harbor logistics where loading and unloading of barges were carried-out with a wheeled loader and a belt conveyor. Total supply chain costs including the best waterway logistics from road side storage to power plant ranged from 10.75 euros to 11.64 euros/MWh in distances of 100-150 km by waterways. The energy-density of forest chips in the barge load was found to be, on average, 25% higher than that in truck hauling, because of the better compaction of chips. Waterway transport is a viable option for long-distance transportation of forest chips in Eastern

  4. Business Management Practices for Small to Medium Sized Forest Products Firms

    OpenAIRE

    Espinoza, Omar Alejandro; Smith, Robert L. (Robert Lee), 1955 August 21-

    2015-01-01

    This book offers advice and information for starting and guiding a small forest products business. It emphasizes the importance of business planning, human resource planning, marketing, and operations and financial management.

  5. Habitat-specific bioaccumulation of methylmercury in invertebrates of small mid-latitude lakes in North America

    Energy Technology Data Exchange (ETDEWEB)

    Chetelat, John, E-mail: john.chetelat@ec.gc.c [Groupe de recherche interuniversitaire en limnologie, Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7 (Canada); Amyot, Marc; Garcia, Edenise [Groupe de recherche interuniversitaire en limnologie, Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7 (Canada)

    2011-01-15

    We examined habitat-specific bioaccumulation of methylmercury (MeHg) in aquatic food webs by comparing concentrations in pelagic zooplankton to those in littoral macroinvertebrates from 52 mid-latitude lakes in North America. Invertebrate MeHg concentrations were primarily correlated with water pH, and after controlling for this influence, pelagic zooplankton had significantly higher MeHg concentrations than littoral primary consumers but lower MeHg than littoral secondary consumers. Littoral primary consumers and pelagic zooplankton are two dominant prey for fish, and greater MeHg in zooplankton is likely sufficient to increase bioaccumulation in pelagic feeders. Intensive sampling of 8 lakes indicated that habitat-specific bioaccumulation in invertebrates (of similar trophic level) may result from spatial variation in aqueous MeHg concentration or from more efficient uptake of aqueous MeHg into the pelagic food web. Our findings demonstrate that littoral-pelagic differences in MeHg bioaccumulation are widespread in small mid-latitude lakes. - Methylmercury levels in dominant invertebrate prey for fish differ between littoral and pelagic habitats within a lake.

  6. Habitat-specific bioaccumulation of methylmercury in invertebrates of small mid-latitude lakes in North America

    International Nuclear Information System (INIS)

    Chetelat, John; Amyot, Marc; Garcia, Edenise

    2011-01-01

    We examined habitat-specific bioaccumulation of methylmercury (MeHg) in aquatic food webs by comparing concentrations in pelagic zooplankton to those in littoral macroinvertebrates from 52 mid-latitude lakes in North America. Invertebrate MeHg concentrations were primarily correlated with water pH, and after controlling for this influence, pelagic zooplankton had significantly higher MeHg concentrations than littoral primary consumers but lower MeHg than littoral secondary consumers. Littoral primary consumers and pelagic zooplankton are two dominant prey for fish, and greater MeHg in zooplankton is likely sufficient to increase bioaccumulation in pelagic feeders. Intensive sampling of 8 lakes indicated that habitat-specific bioaccumulation in invertebrates (of similar trophic level) may result from spatial variation in aqueous MeHg concentration or from more efficient uptake of aqueous MeHg into the pelagic food web. Our findings demonstrate that littoral-pelagic differences in MeHg bioaccumulation are widespread in small mid-latitude lakes. - Methylmercury levels in dominant invertebrate prey for fish differ between littoral and pelagic habitats within a lake.

  7. Monitoring plant tissue nitrogen isotopes to assess nearshore inputs of nitrogen to Lake Crescent, Olympic National Park, Washington

    Science.gov (United States)

    Cox, Stephen E.; Moran, Patrick W.; Huffman, Raegan L.; Fradkin, Steven C.

    2016-05-31

    Mats of filamentous-periphytic algae present in some nearshore areas of Lake Crescent, Olympic National Park, Washington, may indicate early stages of eutrophication from nutrient enrichment of an otherwise highly oligotrophic lake. Natural abundance ratios of stable isotopes of nitrogen (δ15N) measured in plant tissue growing in nearshore areas of the lake indicate that the major source of nitrogen used by these primary producing plants is derived mainly from atmospherically fixed nitrogen in an undeveloped forested ecosystem. Exceptions to this pattern occurred in the Barnes Point area where elevated δ15N ratios indicate that effluent from septic systems also contribute nitrogen to filamentous-periphytic algae growing in the littoral zone of that area. Near the Lyre River outlet of Lake Crescent, the δ15N of filamentous-periphytic algae growing in close proximity to the spawning areas of a unique species of trout show little evidence of elevated δ15N indicating that nitrogen from on-site septic systems is not a substantial source of nitrogen for these plants. The δ15N data corroborate estimates that nitrogen input to Lake Crescent from septic sources is comparatively small relative to input from motor vehicle exhaust and vegetative sources in undeveloped forests, including litterfall, pollen, and symbiotic nitrogen fixation. The seasonal timing of blooms of filamentous-periphytic algal near the lake shoreline is also consistent with nitrogen exported from stands of red alder trees (Alnus rubra). Isotope biomonitoring of filamentous-periphytic algae may be an effective approach to monitoring the littoral zone for nutrient input to Lake Crescent from septic sources.

  8. Bio-mixing due to Diel Vertical Migration of Daphnia spp. in a Small Lake

    Science.gov (United States)

    Simoncelli, Stefano; Wain, Danielle; Thackeray, Stephen

    2016-04-01

    Bio-turbulence or bio-mixing refers to the contribution of living organisms towards the mixing of waters in oceans and lakes. Experimental measurements in an unstratified tank by Wilhelmus & Dabiri (2014) show that zooplankton can trigger fluid instabilities through collective motions and that energy is imparted to scales bigger than organism's size of few mm. Length scales analysis, for low-Reynolds-number organisms in stratified water by Leshansky & Pismen (2010) and Kunze (2011), estimate eddy diffusivity up two orders of magnitude larger than the molecular thermal diffusivity. Very recently, Wand & Ardekani (2015) showed a maximum diffusivity of 10-5 m2/s for millimetre-sized organisms from numerical simulations in the intermediate Reynolds number regime. Here we focus our attention on turbulence generated by the vertical migration of zooplankton in a small lake, mostly populated by Daphnia spp. This very common species, belonging to Cladocera order, is engaged in a vertical migration (DVM) at sunset, with many organisms crossing the thermocline despite the density stratification. During the ascension they may create hydrodynamic disturbances in the lake interior where the stratification usually suppresses the vertical diffusion. We have conducted five turbulence experiments in Vobster Quay, a small (area ˜ 59,000 m2), deep (40m) man-made basin with small wind fetch and steep sides, located in the South West UK. Turbulence was measured with a temperature microstructure profiler. To asses the zooplankton vertical concentration we used a 100 μm mesh net, by collecting and analyzing samples in 8 layers of the lake. A bottom-mounted acoustic Doppler current profiler was also employed to track their concentration and migration with the measured backscatter strength. Measured dissipation rates ɛ during the day showed low turbulence level (<= 10-8 W/Kg) in the thermocline and in the zooplankton layer. Turbulence, during the DVM in two different days, is highest on

  9. Importance of climate change-physical forcing on the increase of cyanobacterial blooms in a small, stratified lake

    Directory of Open Access Journals (Sweden)

    Dolores Planas

    2016-03-01

    Full Text Available The community structure of planktonic cyanobacteria was studied in a dimictic lake in which recurrent summer surface algal blooms have frequently occurred since the beginning of this millennium. In eutrophic-hypereutrophic lakes, epilimnetic cyanobacterial blooms are promoted by increased ambient temperatures and water column thermal stability, which favour the vertical migration of buoyancy-regulating cyanobacteria. Here we propose that intensified external energy (wind that alters thermocline stability could explain the occurence of heavy blooms in the surface of lakes with low external nutrient loading. Specifically, we hypothesized that: i in small stratified lakes with low external nutrient sources, cyanobacterial growth primarily occurs near the lake bottom, where phosphorus is more abundant and light is available; ii we additionally hypothesized that turbulence induced by strong winds increases the amplitude and energy of metalimnetic internal waves and entrains meta- and hypolimnetic water,  rich in nutrients and cyanobacteria, into the epilimnion. The study was done in a small lake (45 Ha, maximum and mean depth 7.2 m and 4.3 m, respectively with mean epilimnetic dissolved phosphorus concentrations ≈ 4 μg L-1 and chlorophyll α ≈ 8 μg L-1.  Vertical temperature profiles during the open season were continuously registered using thermistors.  Weekly vertical profiles of light transmission, phytoplankton distribution and water chemistry were also taken. On one occasion, these variables were measured throughout a continuous 24 h cycle. Results demonstrated that summer cyanobacterial blooms were dominated by Plankthotrix spp., which began their cycle in late spring at the bottom of the lake, and grew to form dense metalimnetic biomass peaks. Time series analysis of isotherms and the Lake number indicated that internal metalimnetic waves (seiches were present through the summer. During the diel sampling cycle, we found that medium to

  10. Small forest cuttings mapped with Landsat digital data

    Science.gov (United States)

    Bryant, E.; Dodge, A. G.; Eger, M. J. E.

    1979-01-01

    The Cooperative Landsat Applications Research Group used computer classification of Landsat digital data to map forest cuttings (clearcuts) in northern New Hampshire. Cuttings as small as 3 hectares were identified. Several ages or conditions of clearcuts could be distinguished. Progress in two methods of duplicating classification categories from one Landsat pass to another are discussed. One method was used in making maps of areas in 1973, 1975, and 1978.

  11. Limnology of Botos Lake, a tropical crater lake in Costa Rica.

    Science.gov (United States)

    Umaña, G

    2001-12-01

    Botos Lake, located at the Poas Volcano complex (Costa Rica) was sampled eight times from 1994 to 1996 for physicochemical conditions of the water column and phytoplanktonic community composition. Depth was measured at fixed intervals in several transects across the lake to determine its main morphometric characteristics. The lake has an outlet to the north. It is located 2580 m above sea level and is shallow, with a mean depth of 1.8 m and a relative depth of 2.42 (surface area 10.33 ha, estimated volume 47.3 hm3). The lake showed an isothermal water column in all occasions, but it heats and cools completely according to weather fluctuations. Water transparency reached the bottom on most occasions (> 9 m). The results support the idea that the lake is polymictic and oligotrophic. The lake has at least 23 species of planktonic algae, but it was always dominated by dinoflagellates, especially Peridinium inconspicuum. The shore line is populated by a sparse population of Isoetes sp. and Eleocharis sp. mainly in the northern shore where the bottom has a gentle slope and the forest does not reach the shore.

  12. Extending WEPP technology to predict fine sediment and phosphorus delivery from forested hillslopes

    Science.gov (United States)

    William Elliot; Erin Brooks; Drea Em Traeumer; Mariana Dobre

    2015-01-01

    In many watersheds, including the Great Lakes and Lake Tahoe Basins, two basins where the land cover is dominated by forests, the pollutants of concern are fine sediments and phosphorus. Forest runoff is generally low in nitrogen, and coarse sediment does not adversely impact the quality of lake waters. Predictive tools are needed to estimate not simply sediment, but...

  13. Small Drones for Community-Based Forest Monitoring: An Assessment of Their Feasibility and Potential in Tropical Areas

    Directory of Open Access Journals (Sweden)

    Jaime Paneque-Gálvez

    2014-06-01

    Full Text Available Data gathered through community-based forest monitoring (CBFM programs may be as accurate as those gathered by professional scientists, but acquired at a much lower cost and capable of providing more detailed data about the occurrence, extent and drivers of forest loss, degradation and regrowth at the community scale. In addition, CBFM enables greater survey repeatability. Therefore, CBFM should be a fundamental component of national forest monitoring systems and programs to measure, report and verify (MRV REDD+ activities. To contribute to the development of more effective approaches to CBFM, in this paper we assess: (1 the feasibility of using small, low-cost drones (i.e., remotely piloted aerial vehicles in CBFM programs; (2 their potential advantages and disadvantages for communities, partner organizations and forest data end-users; and (3 to what extent their utilization, coupled with ground surveys and local ecological knowledge, would improve tropical forest monitoring. To do so, we reviewed the existing literature regarding environmental applications of drones, including forest monitoring, and drew on our own firsthand experience flying small drones to map and monitor tropical forests and training people to operate them. We believe that the utilization of small drones can enhance CBFM and that this approach is feasible in many locations throughout the tropics if some degree of external assistance and funding is provided to communities. We suggest that the use of small drones can help tropical communities to better manage and conserve their forests whilst benefiting partner organizations, governments and forest data end-users, particularly those engaged in forestry, biodiversity conservation and climate change mitigation projects such as REDD+.

  14. Lake Cadagno

    DEFF Research Database (Denmark)

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur...... cycles. The chemocline lies at about 12 m depth, stabilized by density differences of salt-rich water supplied by sub-aquatic springs to the monimolimnion and of electrolyte-poor surface water feeding the mixolimnion. Steep sulphide and light gradients in the chemocline support the growth of a large...... in the chemocline. Small-celled PSB together with the sulfate-reducing bacterium Desulfocapsa thiozymogenes sp. form stable aggregates in the lake, which represent small microenvironments with an internal sulphur cycle. Eukaryotic primary producers in the anoxic zones are dominated by Cryptomonas phaseolus...

  15. Rise and fall of a small ice-dammed lake - Role of deglaciation processes and morphology

    Science.gov (United States)

    Nehyba, Slavomír; Hanáček, Martin; Engel, Zbyněk; Stachoň, Zdeněk

    2017-10-01

    A small ice-dammed lake, which developed along the margin of Nordenskiöldbreen on the northern coast of Adolfbukta, (central Spitsbergen, Svalbard) has been studied by a combination of facies analysis, ground penetrating radar, analysis of photos and satellite imagery, and by surface mapping by Unmanned Aerial Vehicle (drone). The lake existed between the years 1990-2012 and occupied two partial depressions in the bedrock, separated by a bedrock ridge for the dominant period of its history. Whereas the eastern depression was almost completely infilled due to direct fluvial input, the western depression revealed only thin sedimentary cover and was dotted from the eastern depression by an outflow of surficial waters. Gilbert delta deposits with typical tripartite zones of topset, foreset and bottomset were recognised in the eastern depression. Topset was comprised by deposits of a braided river. Foreset is formed by deposits of sediment gravity flows (turbidity currents and debris flows). Bottomset is represented by alternating suspension deposits and deposits of hyperpycnal underflows (low-density turbidity currents). The ruling factors of the evolution of the delta were glacier retreat, bedrock morphology, both affecting the relative lake level, and the rate of sediment delivery. Glacier retreat over stepped and inclined bedrock morphology led to delta prograding and downstepping. The recognised fluvio-deltaic terraces revealed four lake level falls followed by fluvial downcutting, erosion and redeposition of the older deltaic/lake deposits, the shifting of the lake's position towards the damming glacier and the transition of the sediment input in the same direction. The termination of the lake was a result of further glacier retreat and the opening of subglacial drainage.

  16. Limnology of nine small lakes, Matanuska-Susitna Borough, Alaska, and the survival and growth rates of rainbow trout

    Science.gov (United States)

    Woods, P.F.

    1985-01-01

    The survival and growth rates of rainbow trout (Salmo gairdnieri) were concurrently measured with selected limnological characteristics in nine small (surface area Gasterosteus aculeatus) also influenced survival of rainbow trout but their effects were overshadowed by winterkill. Predictive capability was also reduced because of inconsistencies in rankings generated by each of the four limnological variables chosen as indicators of potential biological productivity. A lake ranked low in productivity by one variable was commonly ranked high in productivity by another variable. The survivability of rainbow trout stocked in lakes such as these nine may be a more important indicator of potential biomass production than are indicators of lake fertility. Assessments of a lake 's susceptibility to winterkill and the degree of competition with threespine stickleback are suggested as important topics for additional research. (Author 's abstract)

  17. Estimation of mercury emissions from forest fires, lakes, regional and local sources using measurements in Milwaukee and an inverse method

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2012-10-01

    Full Text Available Gaseous elemental mercury is a global pollutant that can lead to serious health concerns via deposition to the biosphere and bio-accumulation in the food chain. Hourly measurements between June 2004 and May 2005 in an urban site (Milwaukee, WI show elevated levels of mercury in the atmosphere with numerous short-lived peaks as well as longer-lived episodes. The measurements are analyzed with an inverse model to obtain information about mercury emissions. The model is based on high resolution meteorological simulations (WRF, hourly back-trajectories (WRF-FLEXPART and a chemical transport model (CAMx. The hybrid formulation combining back-trajectories and Eulerian simulations is used to identify potential source regions as well as the impacts of forest fires and lake surface emissions. Uncertainty bounds are estimated using a bootstrap method on the inversions. Comparison with the US Environmental Protection Agency's National Emission Inventory (NEI and Toxic Release Inventory (TRI shows that emissions from coal-fired power plants are properly characterized, but emissions from local urban sources, waste incineration and metal processing could be significantly under-estimated. Emissions from the lake surface and from forest fires were found to have significant impacts on mercury levels in Milwaukee, and to be underestimated by a factor of two or more.

  18. Paper birch (Wiigwaas) of the Lake States, 1980-2010

    Science.gov (United States)

    W. Keith Moser; Mark H. Hansen; Dale Gormanson; Jonathan Gilbert; Alexandra Wrobel; Marla R. Emery; Michael J. Dockry

    2015-01-01

    Data on paper birch (Betula papyrifera L.; wiigwaas in the Ojibwe language), collected by the Forest Inventory and Analysis (FIA) program of the U.S. Forest Service on forested lands in the Great Lakes region (Michigan, Minnesota, and Wisconsin) from 1980 through 2010, are reported. Also presented are results and analysis of a supplemental inventory...

  19. Rapid Assessments of Amazon Forest Structure and Biomass Using Small Unmanned Aerial Systems

    Directory of Open Access Journals (Sweden)

    Max Messinger

    2016-07-01

    Full Text Available Unmanned aerial vehicles (UAVs can provide new ways to measure forests and supplement expensive or labor-intensive inventory methods. Forest carbon, a key uncertainty in the global carbon cycle and also important for carbon conservation programs, is typically monitored using manned aircraft or extensive forest plot networks to estimate aboveground carbon density (ACD. Manned aircraft are only cost-effective when applied to large areas (>100,000 ha, while plot networks are most effective for total C stock estimation across large areas, not for quantifying spatially-explicit variation. We sought to develop an effective method for frequent and accurate ACD estimation at intermediate scales (100–100,000 ha that would be sensitive to small-scale disturbance. Using small UAVs, we collected imagery of 516 ha of lowland forest in the Peruvian Amazon. We then used a structure-from-motion (SFM approach to create a 3D model of forest canopy. Comparing SFM- and airborne Light Detection and Ranging (LiDAR-derived estimates of canopy height and ACD, we found that SFM estimates of top-of-canopy height (TCH and ACD were highly correlated with previous LiDAR estimates (r = 0.86–0.93 and r = 0.73–0.94 for TCH and ACD, respectively, at 0.1–4 ha grain sizes, with r = 0.92 for ACD determination at the 1 ha scale, despite SFM and LiDAR measurements being separated by two years in a dynamic forest. SFM and LiDAR estimates of mean TCH and mean ACD were highly similar, differing by only 0.4% and 0.04%, respectively, within mature forest. The technique allows inexpensive, near-real-time monitoring of ACD for ecological studies, payment for ecosystem services (PES ventures, such as reducing emissions from deforestation and forest degradation (REDD+, forestry enterprises, and governance.

  20. Long-Term Trends in Nutrient Concentrations and Fluxes in Streams Draining to Lake Tahoe, California

    Science.gov (United States)

    Domagalski, J. L.

    2017-12-01

    Lake Tahoe, situated in the rain shadow of the eastern Sierra Nevada at an elevation of 1,897 meters, has numerous small to medium sized tributaries that are sources of nutrients and fine sediment. The Tahoe watershed is relatively small and the surface area of the lake occupies about 38% of the total watershed area (1,313 km2). Each stream contributing water to the lake therefore also occupies a small watershed, mostly forested, with typical trees being Jeffrey, Ponderosa, or Sugar Pine and White Fir. Outflow from the lake contributes to downstream uses such as water supply and ecological resources. Only about 6% of the watershed is urbanized or residential land, and wastewater is exported to adjacent basins and not discharged to the lake as part of a plan to maintain water clarity. The lake's exceptional clarity has been diminishing due to phytoplankton and fine sediment, prompting development of management plans to improve water quality. Much of the annual discharge and flux of nutrients to the lake results from snowmelt in the spring and summer months, and climatic changes have begun to shift this melt to earlier time frames. Winter rains on urbanized land also contribute to nutrient loads. To understand the relative importance of land use, climate, and other factors affecting stream concentrations and fluxes, a Weighted Regression on Time Discharge and Season (WRTDS) model documented trends over a time frame of greater than 25 years. Ten streams have records of discharge, nutrient (NO3, NH3, OP, TP, TKN) and sediment data to complete this analysis. Both urbanized and non-urbanized locations generally show NO3 trending down in the 1980s. Some locations show initially decreasing orthophosphate trends, followed by small significant increases in concentration and fluxes starting around 2000 to 2005. Although no wastewater enters the streams, ammonia concentrations mimic those of orthophosphate, with initially negative trends in concentration and flux followed by

  1. Importance of woodlots to local communities, small scale entrepreneurs and indigenous forest conservation – A case study

    CSIR Research Space (South Africa)

    Ham, C

    2000-01-01

    Full Text Available forestry, South Africa The Importance of Woodlots to Local Communities, Small-scale Entrepreneurs and Indigenous Forest Conservation A case study Cori Ham ii The Importance of Woodlots to Local Communities, Small Scale Entrepreneurs... by the financial support of the UK Department for International Development and the European Commission iii Citation: Ham, C. 2000. The importance of woodlots to local communities, small scale entrepreneurs and indigenous forest conservation– A case study...

  2. Vegetation changes and human activity around Lake Łańskie (Olsztyn Lake District, NE Poland from the mid Holocene, based on palynological study

    Directory of Open Access Journals (Sweden)

    Madeja Jacek

    2013-12-01

    Full Text Available Bottom sediments of Lake Łańskie in NE Poland (Olsztyn Lake District were studied by pollen analysis, and vegetation changes from ca 4800 BC to modern times were reconstructed based on the results. Due to rapid sedimentation the changes in plant cover are recorded with high resolution. The variation of pollen spectra composition reflects changing shares of deciduous trees and the continuous dominance of pine forest. Nowadays the surroundings of Lake Łańskie are also heavily forested but as early as 1100 AD the deciduous trees began to be eliminated. On the basis of pollen data, five phases of increased human activity were distinguished. Based on the available archaeological chronology of local settlements, the first stage is connected with para-Neolithic groups of Ząbie-Szestno type and the Lusatian culture. They are followed by the West Baltic Barrow culture, Wielbark culture and Early Medieval Prussian tribes. The pollen record shows low intensity of exploitation of the terrain around Lake Łańskie, probably attributable to the brevity of episodes of human occupation in the near vicinity of the lake. The last phase, covering part of the Middle Ages (since ca 1000 AD and modern times, is reflected in the most distinct vegetation changes on the pollen diagram, caused by increased intensity of settlement. In spite of the distinct diminution of forest cover around the lake the scale of deforestation was much lower than at other sites in NE Poland.

  3. First evidence of successful natural reproduction by planted lake trout in Lake Huron

    Science.gov (United States)

    Nester, Robert T.; Poe, Thomas P.

    1984-01-01

    Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

  4. Impact of mining and forest regeneration on small mammal biodiversity in the Western Region of Ghana.

    Science.gov (United States)

    Attuquayefio, Daniel K; Owusu, Erasmus H; Ofori, Benjamin Y

    2017-05-01

    Much of the terrestrial biodiversity in sub-Saharan Africa is supported by tropical rainforest. Natural resource development, particularly surface mining in the rainforest, poses great risks to the region's rich and endemic biodiversity. Here, we assessed the impact of surface mining and the success of forest rehabilitation on small mammal diversity in the Western Region of Ghana. We surveyed small mammals in the project area and two adjoining forest reserves (control sites) before the mining operation and 10 years after mine closure and forest rehabilitation (topsoil replacement and revegetation). The forest reserves recorded higher species abundance than the mining areas. Majority of the species captured in the forest reserves, including Hylomyscus alleni, Praomys tullbergi, Malacomys cansdalei, and Hybomys trivirgatus, are forest obligate species. Only one individual each of H. alleni and P. tullbergi was captured in the naturally regenerated areas (core areas of mining activities that were allowed to revegetate naturally), while 32 individuals belonging to four species (Lophuromys sikapusi, Mus musculoides, Mastomys erythroleucus, and Crocidura olivieri) were recorded in the rehabilitated areas. Our data suggested negative effects of mining on small mammal diversity and the restoration of species diversity and important ecological processes after rehabilitation of altered habitats. We strongly encourage deliberate conservation efforts, particularly the development of management plans that require the restoration of degraded land resulting from mining activities.

  5. Small mammal community succession on the beach of Dongting Lake, China after the Three Gorges Project.

    Science.gov (United States)

    Zhang, Meiwen; Wang, Yong; Li, Bo; Guo, Cong; Huang, Guoxian; Shen, Guo; Zhou, Xunjun

    2014-06-01

    Although the Three Gorges Project (TGP) may have affected the population structure and distribution of plant and animal communities, few studies have analyzed the effect of this project on small mammal communities. Therefore, the present paper compares the small mammal communities inhabiting the beaches of Dongting Lake using field investigations spanning a 20-year period, both before and after the TGP was implemented. Snap traps were used throughout the census. The results indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam. First, species abundance on the beaches increased after the project commenced. The striped field mouse (Apodemus agrarius) and the Norway rat (Rattus norvegicus), which rarely inhabited the beach before the TGP, became abundant (with marked population growth) once water was impounded by the Three Gorges Reservoir. Second, dominant species concentration indices exhibited a stepwise decline, indicating that the community structure changed from a single dominant species to a more diverse species mix after TGP implementation. Third, the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches. A significant difference in diversity indices was obtained before and after the TGP operation. Similarity indices also indicate a gradual increase in species numbers. Hence, a long-term project should be established to monitor the population fluctuations of the Yangtze vole (Microtus fortis), the striped field mouse and the Norway rat to safeguard against population outbreaks (similar to the Yangtze vole outbreak in 2007), which could cause crop damage to adjacent farmland, in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley

  6. Small mammal populations and ecology in the Kings River Sustainable Forest Ecosystems Project area

    Science.gov (United States)

    William F. Jr. Laudenslayer; Roberta J. Fargo

    2002-01-01

    Small mammals are important components of woodlands and forests. Since 1992, we have been studying several aspects of small mammal ecology in oak woodlands in western foothills of the southern Sierra Nevada. Assemblages of small, nocturnal mammal species are dominated by the brush mouse (Peromyscus boylii), California mouse (P. californicus...

  7. Floristic diversity of midforest lakes (Sobibór Landscape Park, Poland

    Directory of Open Access Journals (Sweden)

    Sender Joanna

    2016-12-01

    Full Text Available Aquatic vegetation greatly impacts lake functions. Forest ecosystems surrounding lakes are effective protection zone of lakes and their associated flora and fauna. The presence of aquatic plants depends on many factors, including the chemical composition and acidity of water, the shape of the lake catchment, the angle of slope along shorelines and the management of surrounding lands. Natural ecosystems throughout Eastern Europe are threatened by anthropogenic activities. Aquatic systems and bogs are particularly sensitive to disturbances. The aim of the study was to determine the influence of land management, forest type and stand age on aquatic plant colonisation within lakes as well as to quantify and qualify the structure of macrophyte communities within two lakes, Płotycze Sobiborskie and Orchowe, located in the Sobibór Landscape Park in western Poland. Even though there were few bogs within the catchment areas and lake buffer zones, where they did occur they had the greatest effect on macrophyte presence. The results of this research indicate that in the absence of anthropogenic disturbances midforest water-bog complexes are relatively stable systems and preserve their natural character. The applied multi-criteria evaluation of macrophytes in the studied lakes and their surrounding buffer zones and catchment areas allowed the lakes to be characterised as lakes with a good ecological status.

  8. Wildlife in the Upper Great Lakes Region: a community profile.

    Science.gov (United States)

    Janine M. Benyus; Richard R. Buech; Mark D. Nelson

    1992-01-01

    Wildlife habitat data from seven Great Lakes National Forests were combined into a wildlife-habitat matrix named NORTHWOODS. The composite NORTHWOODS data base is summarized. Multiple queries of NORTHWOODS were used to profile the wildlife community of the Upper Great Lakes region.

  9. Forest Distribution on Small Isolated Hills and Implications on Woody Plant Distribution under Threats of Global Warming

    Directory of Open Access Journals (Sweden)

    Chi-Cheng Liao

    2012-09-01

    Full Text Available Treelines have been found to be lower in small isolated hilltops, but the specific dynamics behind this unique phenomenon are unknown. This study investigates the distribution patterns of woody plants in Yangmingshan National Park (YMSNP, Northern Taiwan in search of the limitation mechanisms unique to small isolated hills, and to evaluate potential threats under global warming. Forests distributed between 200 to 900 m above sea level (ASL. Remnant forest fragments between 400 and 900 m ASL, have the highest species richness, and should be protected to ensure future forest recovery from the former extensive artificial disturbance. The lower boundary is threatened by urban and agricultural development. The lack of native woody species in these low elevation zones may cause a gap susceptible to invasive species. A consistent forest line at 100 m below mountain tops regardless of elevation suggests a topography-induced instead of an elevation-related limiting mechanism. Therefore, upward-shift of forests, caused by global warming, might be limited at 100 m below hilltops in small isolated hills because of topography-related factors. The spatial range of woody plants along the altitudinal gradient, thus, is likely to become narrower under the combined pressures of global warming, limited elevation, exposure-related stress, and artificial disturbance. Management priorities for forest recovery are suggested to include preservation of remnant forest fragments, increasing forest connectivity, and increasing seedling establishment in the grasslands.

  10. Relation between small-mammal species composition and anthropic variables in the Brazilian Atlantic Forest

    Directory of Open Access Journals (Sweden)

    N. Olifiers

    Full Text Available Anthropic activities are frequently related in many ways to forest fragmentation and alteration of natural communities. In this study, we correlate the presence of hunting, tourism activity, agriculture/pasturing, and the distance of the study sites to the nearest human residences with the species composition of small Atlantic forest mammals. To do this, we utilize a multiple regression analysis of similarity matrices. The presence of both agriculture/pasturing and human residences near the study sites proved to be determinant factors in species composition of small mammals of the studied areas. Working with socioeconomic variables related directly with the study site could be a reliable and a direct way to predict the influence of human presence and entailed activity on small mammal communities.

  11. [Composition characteristics and source analysis of major ions in four small lake-watersheds on the Tibetan Plateau, China].

    Science.gov (United States)

    Li, He; Li, Jun; Liu, Xiao-Long; Yang, Xi; Zhang, Wei; Wang, Jie; Niu, Ying-Quan

    2015-02-01

    To investigate the ionic compositions of small lake-watersheds on the Tibetan Plateau, water samples from the brackish lakes (Pung Co (lake), Angrenjin Co and Dajia Co), the freshwater lake (Daggyaima Co), their inflowing rivers and the hot spring (Dagejia Geothermal Field), were collected during July-August 2013. The results showed that the major anions and cations of the brackish lakes were HCO3-, SO4(2-) and Na+, respectively, and the hydrochemical types were HCO3-SO4-Na and HCO3-Na. The major anions and cations of the inflowing rivers and the freshwater lake were HCO3-, SO4(2-) and Ca2+, Mg2+, respectively, and the hydrochemical types were HCO3-Ca, HCO3-Ca-Mg, HCO3-Mg-Ca, HCO3-SO4-Ca and SO4-HCO3- Ca. The major anions and cations of the hot spring were HCO3- and Na+, respectively, and the hydrochemical type was HCO3-Na. Water chemistry in the brackish lakes was primarily dominated by evaporation-crystallization processes, while the inflowing rivers and the freshwater lake were mainly influenced by carbonate weathering, and the hot spring was mainly controlled by hot water-granite interaction. Ca2+ was preferentially removed over Mg2+ from the water when carbonate minerals precipitation occured, which resulted in the high Mg2+/Ca2+ molar ratios of the brackish lakes. In the contribution of cation compositions, the largest contribution was carbonate weathering (54% - 79%), followed by silicate weathering (13% -29%) and evaperite dissolution (4% -23%), and the smallest was atmospheric input (3% - 7%).

  12. From "Duck Factory" to "Fish Factory": Climate induced changes in vertebrate communities of prairie pothole wetlands and small lakes

    Science.gov (United States)

    McLean, Kyle I.; Mushet, David M.; Stockwell, Craig A.

    2016-01-01

    The Prairie Pothole Region’s myriad wetlands and small lakes contribute to its stature as the “duck factory” of North America. The fishless nature of the region’s aquatic habitats, a result of frequent drying, freezing, and high salinity, influences its importance to waterfowl. Recent precipitation increases have resulted in higher water levels and wetland/lake freshening. In 2012–13, we sampled chemical characteristics and vertebrates (fish and salamanders) of 162 Prairie Pothole wetlands and small lakes. We used non-metric multidimensional scaling, principal component analysis, and bootstrapping techniques to reveal relationships. We found fish present in a majority of sites (84 %). Fish responses to water chemistry varied by species. Fathead minnows (Pimephales promelas) and brook sticklebacks (Culaea inconstans) occurred across the broadest range of conditions. Yellow perch (Perca flavescens) occurred in a smaller, chemically defined, subset. Iowa darters (Etheostoma exile) were restricted to the narrowest range of conditions. Tiger salamanders (Ambystoma mavortium) rarely occurred in lakes with fish. We also compared our chemical data to similar data collected in 1966–1976 to explore factors contributing to the expansion of fish into previously fishless sites. Our work contributes to a better understanding of relationships between aquatic biota and climate-induced changes in this ecologically important area.

  13. Impacts of forest farm practice on small to medium-sized mammals at Kemasul forest reserve, Pahang, Malaysia

    Science.gov (United States)

    Razali, Nor Bazilah; Abdul-Rahim, Ahmad Rizal; Md-Nor, Shukor; Mohd-Taib, Farah Shafawati

    2018-04-01

    Exploitation of forest for commercial agriculture has taken toll on wildlife species worldwide. A forest farm project with the aim of compensating the forest loss has been implemented in Kemasul Forest Reserve, of Pahang State, Malaysia through plantation of fast growing and adaptable plant species. The objective of this study is to determine the impact of this practice on diversity. The study was conducted in a long strip of forest fragment, where two study sites with different landscape matrix types were chosen; oil palm plantation (JR) and Acacia mangium plantations (CM). A total of 75 individuals from 13 species and six families were collected at both sites. The result shows forest with A. mangium plantations matrix types yield higher species diversity. There are 10 shared species that can be found at both study sites including Callosciurus notatus, Hystrix brachyura, Macaca nemestrina, and Tupaia glis. However, some species only existed at selected sites such as Leopoldamys sabanus which can only be found at JR. On the other hand, Callosciurus nigrovittatus, Viverra tangalunga and Paradoxurus hermaphroditus were only recorded at CM. Out of all individuals collected, four of them are protected species as reported by IUCN. Callosciurus nigrovittatus is listed as Near Threatened while the other three species (Maxomys rajah, Maxomys whiteheadi, and Macaca nemestrina) are Vulnerable. If conservation efforts in Kemasul Forest Reserved are neglected, these four species would be exposed to critical threats that might cause them facing extinction in the future. Mann Whitney U test shows no significant difference of distribution and species richness of small to medium-sized mammals in both study sites (U=51.5, p=0.59). This study therefore reveals that although the compensatory forest plantation initiatives yield positive effect on diversity of mammal's species, it does not necessarily provide ample food resources to the wildlife, instead it serves as important buffer

  14. Using small area estimation and Lidar-derived variables for multivariate prediction of forest attributes

    Science.gov (United States)

    F. Mauro; Vicente Monleon; H. Temesgen

    2015-01-01

    Small area estimation (SAE) techniques have been successfully applied in forest inventories to provide reliable estimates for domains where the sample size is small (i.e. small areas). Previous studies have explored the use of either Area Level or Unit Level Empirical Best Linear Unbiased Predictors (EBLUPs) in a univariate framework, modeling each variable of interest...

  15. Ecological Importance of Small-Diameter Trees to the Structure, Diversity and Biomass of a Tropical Evergreen Forest at Rabi, Gabon.

    Science.gov (United States)

    Memiaghe, Hervé R; Lutz, James A; Korte, Lisa; Alonso, Alfonso; Kenfack, David

    2016-01-01

    Tropical forests have long been recognized for their biodiversity and ecosystem services. Despite their importance, tropical forests, and particularly those of central Africa, remain understudied. Until recently, most forest inventories in Central Africa have focused on trees ≥10 cm in diameter, even though several studies have shown that small-diameter tree population may be important to demographic rates and nutrient cycling. To determine the ecological importance of small-diameter trees in central African forests, we used data from a 25-ha permanent plot that we established in the rainforest of Gabon to study the diversity and dynamics of these forests. Within the plot, we censused 175,830 trees ≥1 cm dbh from 54 families, 192 genera, and 345 species. Average tree density was 7,026 trees/ha, basal area 31.64 m2/ha, and above-ground biomass 369.40 Mg/ha. Fabaceae, Ebenaceae and Euphorbiaceae were the most important families by basal area, density and above-ground biomass. Small-diameter trees (1 cm ≥ dbh tree population, 16.5% of basal area, and 4.8% of the above-ground biomass. They also had diversity 18% higher at family level, 34% higher at genus level, and 42% higher at species level than trees ≥10 cm dbh. Although the relative contribution of small-diameter trees to biomass was comparable to other forests globally, their contribution to forest density, and diversity was disproportionately higher. The high levels of diversity within small-diameter classes may give these forests high levels of structural resilience to anthropogenic/natural disturbance and a changing climate.

  16. Climatic Characteristics of the Subtropical Mountainous Cloud Forest at the Yuanyang Lake Long-Term Ecological Research Site, Taiwan

    Directory of Open Access Journals (Sweden)

    I-Ling Lai

    2006-12-01

    Full Text Available To better understand the climatic characteristics in a subtropical mountainous cloud forest at the Yuanyang Lake long-term ecological research site, weather data collected from January 1994 to December 2004 were analyzed in the present study. The obvious seasonal changes in climatic factors were observed at this site. The annual mean air temperature was 12.7°C. The lowest temperature was recorded in February (monthly mean 5.9°C, and the highest one was taken in July (monthly mean 18.1°C. Winter featured light rain with a prolonged occurrence of fog, resulting in a large reduction of radiation. In summer, fog occurred once in the early morning and the other time from afternoon to evening. The latter one was associated with the wind direction changes and usually accompanied with short moderate to heavy convective rain. Consequently the photosynthetic photon flux density (PPFD was high in the morning but reduced drastically in the afternoon. Typhoons occurred in the summer had contributed to 37% of the annual rainfall, usually resulting in torrential rain events and sharp increases in the water level of this lake. As a matter of fact, perhumid environment of this site was attributed to abundant rainfall (mean annual precipitation 3396 mm and high frequency (up to 40% of foggy time. Such conditions would reduce the intensity of solar radiation and PPFD. The average annual solar radiation at the site was 2475 MJ m-2, and annual PPFD was 5713 mol m-2. The average degree of reduction of PPFD under foggy condition was up to 88%. Such climatic characteristics are suggested to constrain the growth of plants and play an important role in competition among plant species in this cloud forest. It is considered that the distinct seasonal fluctuation in environmental factors, perhumid and dim light conditions are the most distinguished characteristics of this subtropical mountainous cloud forest ecosystem.

  17. Small mammals from the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala

    Science.gov (United States)

    Matson, Jason O.; Ordóñez-Garza, Nicté; Woodman, Neal; Bulmer, Walter; Eckerlin, Ralph P.; Hanson, J. Delton

    2014-01-01

    We surveyed the small mammals of remnant mixed hardwood-coniferous cloud forest at elevations ranging from 2,100–2,300 m in the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala. Removal-trapping using a combination of live traps, snap traps, and pitfall traps for 6 days in January 2007 resulted in 175 captures of 15 species of marsupials, shrews, and rodents. This diversity of small mammals is the highest that we have recorded from a single locality of the 10 visited during eight field seasons in the highlands of Guatemala. Based on captures, the most abundant species in the community of small mammals is Peromyscus grandis (n = 50), followed by Handleyomys rhabdops (n = 27), Heteromys desmarestianus(n = 18), Reithrodontomys mexicanus (n = 17), Handleyomys saturatior (n = 16), Sorex veraepacis (n = 15), and Scotinomys teguina (n = 13). The remaining eight species were represented by one to five individuals.

  18. Does road salting confound the recovery of the microcrustacean community in an acidified lake?

    Science.gov (United States)

    Jensen, Thomas Correll; Meland, Sondre; Schartau, Ann Kristin; Walseng, Bjørn

    2014-04-15

    Numerous boreal lakes across the Northern Hemisphere recovering from acidification are experiencing a simultaneous increase in chloride (Cl) concentrations from road salting. Increasing Cl may have profound effects on the lake ecosystem. We examine if an increase in Cl from road salting has modified the recovery of the microcrustacean community in an acidified boreal lake undergoing chemical recovery (study lake). Results from the study lake were compared with an acidified "reference lake". The community changed during the study period in the study lake mainly driven by the reduction in acidification pressure. Despite the community changes and an increase in species richness, the absence of several acid sensitive species, previously occurring in the lake, indicates a delayed biological recovery relative to the chemical recovery. Moreover, changes in occurrence of acid sensitive and acid tolerant species indicated that the biological recovery was slower in the study lake compared to the "reference". Although recurrent episodes of high aluminum and low pH and decreasing Ca are likely important factors for the delay, these do not explain, for instance, the shift from Cyclops scutifer to Bosmina longispina in the study lake. Although the contribution of Cl was not significant, the correlation between Cl and the variation in microcrustacean community was twice as high in the study lake compared to the "reference". We argue that small, sheltered forest lakes may be especially sensitive to increased Cl levels, through changes in pattern of stratification, thus providing a mechanism for the shift from C. scutifer to B. longispina. The reduction of the acidification pressure seems to override the Cl effects on microcrustaceans at low Cl levels in salt-affected lakes recovering from acidification. However, prognoses for growing traffic and increasing road salting raise concern for many recovering lakes located in proximity to roads and urbanized areas. Copyright © 2014

  19. The Proliferation and Illicit Trafficking of Small Arms and Light Weapons in the Great Lakes and Horn of Africa

    National Research Council Canada - National Science Library

    Kiugu, Aphaxard M

    2007-01-01

    In Africa, the effect of the proliferation of small arms and light weapons (SALW) continues to impact negatively on socioeconomic development, particularly within the Great Lakes and Horn of Africa...

  20. 77 FR 57556 - Lake Tahoe Basin Federal Advisory Committee (LTBFAC)

    Science.gov (United States)

    2012-09-18

    ... Management Unit, Forest Service, 35 College Drive, South Lake Tahoe, CA 96150, (530) 543-2773, (530) 543-0956... received at 35 College Drive, South Lake Tahoe, CA 96150. Please call ahead to 530-543-2773 to facilitate... Standard Time, Monday through Friday. SUPPLEMENTARY INFORMATION: The following business will be conducted...

  1. Conserving tropical tree diversity and forest structure: the value of small rainforest patches in moderately-managed landscapes.

    Science.gov (United States)

    Hernández-Ruedas, Manuel A; Arroyo-Rodríguez, Víctor; Meave, Jorge A; Martínez-Ramos, Miguel; Ibarra-Manríquez, Guillermo; Martínez, Esteban; Jamangapé, Gilberto; Melo, Felipe P L; Santos, Bráulio A

    2014-01-01

    Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (<100 ha) can be highly valuable for the conservation of tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services.

  2. Conserving Tropical Tree Diversity and Forest Structure: The Value of Small Rainforest Patches in Moderately-Managed Landscapes

    Science.gov (United States)

    Hernández-Ruedas, Manuel A.; Arroyo-Rodríguez, Víctor; Meave, Jorge A.; Martínez-Ramos, Miguel; Ibarra-Manríquez, Guillermo; Martínez, Esteban; Jamangapé, Gilberto; Melo, Felipe P. L.; Santos, Bráulio A.

    2014-01-01

    Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services. PMID:24901954

  3. Vertical distribution of 137Cs in lake sediments in post-Chernobyl period

    International Nuclear Information System (INIS)

    Gorgun, T.V.; Putyrskaya, V.V.; Klemt, E.; Goncharova, N.V.

    2011-01-01

    The vertical distribution of 137 Cs was studied in one of the glacial lakes situated in the region of Tuchola Forest National Park (Poland). Radiocaesium was used for sedimentation rates estimation and dating of the sediment layers of the lake.

  4. Improving erosion modeling on forest roads in the Lake Tahoe Basin: Small plot rainfall simulations to determine saturated hydraulic conductivity and interrill erodibility

    Science.gov (United States)

    N. S. Copeland; R. B. Foltz

    2009-01-01

    Lake Tahoe is renowned for its beauty and exceptionally clear water. The Tahoe basin economy is dependent upon the protection of this beauty and the continued availability of recreational opportunities in the area; however, scientists estimate that the continued increase in fine sediment and nutrient transport to the lake threatens to diminish this clarity in as little...

  5. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

    Science.gov (United States)

    Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

    2006-01-01

    Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

  6. Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

    DEFF Research Database (Denmark)

    Vestergaard, Ole Skafte; Sand-Jensen, Kaj

    2000-01-01

    We examined the relationship between environmental factors and the richness of submerged macrophytes species in 73 Danish lakes, which are mainly small, shallow, and have mesotrophic to hypertrophic conditions. We found that mean species richness per lake was only 4.5 in acid lakes of low...... alkalinity but 12.3 in lakes of high alkalinity due to a greater occurrence of the species-rich group of elodeids. Mean species richness per lake also increased significantly with increasing Secchi depth. No significant relationship between species richness and lake surface area was observed among the entire...... group of lakes or a subset of eutrophic lakes, as the growth of submerged macrophytes in large lakes may be restricted by wave action in shallow water and light restriction in deep water. In contrast, macrophyte species richness increased with lake surface area in transparent lakes, presumably due...

  7. Ecological position of 'small barbs' and their potential for fisheries: an option to reduce fishing pressure on 'large barbs' of Lake Tana (Ethiopia)?

    NARCIS (Netherlands)

    Dejen, E.; Osse, J.W.M.; Sibbing, F.A.

    2004-01-01

    The two barbs, Barbus humilis and Barbus tanapelagius are important pelagic fish in Lake Tana. These 'small barb' species (<10 cm fork length) play a key role in the Lake's ecosystem as a link between zooplankton and the top predators, mostly 'large barbs'. This paper presents an overview on the

  8. Financing Sustainable Small-Scale Forestry: Lessons from Developing National Forest Financing Strategies in Latin America

    Directory of Open Access Journals (Sweden)

    Herman Savenije

    2010-12-01

    Full Text Available The problems that hamper the financing of sustainable forest management (SFM are manifold and complex. However, forestry is also facing unprecedented opportunities. The multiple functions and values of forests are increasingly recognized as part of the solution to pressing global issues (e.g., climate change, energy scarcity, poverty, environmental degradation, biodiversity loss and raw material supply. Emerging initiatives to enhance forest carbon stocks and cut greenhouse gas emissions associated with forest clearing (known as REDD+, together with voluntary carbon markets, are offering additional funding options for SFM. Indigenous peoples, local communities and small scale farmers feature as key players in the discourse on implementing such initiatives. Based on the experience of countries developing national forest financing strategies and instruments, we suggest the following points be considered when financing such initiatives, particularly for small scale forestry: (1 Integrate financing of REDD+ and similar initiatives within broader national strategies for SFM financing; (2 Design REDD+ finance mechanisms that are ‘community ready’, i.e., tailored to local realities; (3 Consider existing livelihood strategies as the starting point; (4 Build on existing structures, but be mindful of their strengths and weaknesses; (5 Be strategic with your priority actions; and (6 Promote innovation, knowledge sharing and information exchange.

  9. Importance of Small Isolated Wetlands for Herpetofaunal Diversity in Managed, Young Growth Forests in the Coastal Plain of South Carolina

    International Nuclear Information System (INIS)

    Russell, K.R.; Guynn, D.C. Jr.; Hanlin, H.G.

    2002-01-01

    Assessment and comparison of richness, abundance and difference of herpetofauna at five small isolated wetlands located within a commercial forest landscape in the South Carolina Coastal Plain. Data indicates small isolated wetlands are focal points of herpetofaunal richness and abundance in managed coastal plain forest and contribute more to regional biodiversity than is implied by their small size or ephemeral hydrology

  10. Contrasting Patterns of Damage and Recovery in Logged Amazon Forests From Small Footprint LiDAR Data

    Science.gov (United States)

    Morton, D. C.; Keller, M.; Cook, B. D.; Hunter, Maria; Sales, Marcio; Spinelli, L.; Victoria, D.; Andersen, H.-E.; Saleska, S.

    2012-01-01

    Tropical forests ecosystems respond dynamically to climate variability and disturbances on time scales of minutes to millennia. To date, our knowledge of disturbance and recovery processes in tropical forests is derived almost exclusively from networks of forest inventory plots. These plots typically sample small areas (less than or equal to 1 ha) in conservation units that are protected from logging and fire. Amazon forests with frequent disturbances from human activity remain under-studied. Ongoing negotiations on REDD+ (Reducing Emissions from Deforestation and Forest Degradation plus enhancing forest carbon stocks) have placed additional emphasis on identifying degraded forests and quantifying changing carbon stocks in both degraded and intact tropical forests. We evaluated patterns of forest disturbance and recovery at four -1000 ha sites in the Brazilian Amazon using small footprint LiDAR data and coincident field measurements. Large area coverage with airborne LiDAR data in 2011-2012 included logged and unmanaged areas in Cotriguacu (Mato Grosso), Fiona do Jamari (Rondonia), and Floresta Estadual do Antimary (Acre), and unmanaged forest within Reserva Ducke (Amazonas). Logging infrastructure (skid trails, log decks, and roads) was identified using LiDAR returns from understory vegetation and validated based on field data. At each logged site, canopy gaps from logging activity and LiDAR metrics of canopy heights were used to quantify differences in forest structure between logged and unlogged areas. Contrasting patterns of harvesting operations and canopy damages at the three logged sites reflect different levels of pre-harvest planning (i.e., informal logging compared to state or national logging concessions), harvest intensity, and site conditions. Finally, we used multi-temporal LiDAR data from two sites, Reserva Ducke (2009, 2012) and Antimary (2010, 2011), to evaluate gap phase dynamics in unmanaged forest areas. The rates and patterns of canopy gap

  11. Climatic changes inferred fron analyses of lake-sediment cores, Walker Lake, Nevada

    International Nuclear Information System (INIS)

    Yang, In Che.

    1989-01-01

    Organic and inorganic fractions of sediment collected from the bottom of Walker Lake, Nevada, have been dated by carbon-14 techniques. Sedimentation rates and the organic-carbon content of the sediment were correlated with climatic change. The cold climate between 25,000 and 21,000 years ago caused little runoff, snow accumulation on the mountains, and rapid substantial glacial advances; this period of cold climate resulted in a slow sedimentation rate (0.20 millimeter per year) and in a small organic-carbon content in the sediment. Also, organic-carbon accumulation rates in the lake during this period were slow. The most recent period of slow sedimentation rate and small organic-carbon content occurred between 10,000 and 5500 years ago, indicative of low lake stage and dry climatic conditions. This period of dry climate also was evidenced by dry conditions for Lake Lahontan in Nevada and Searles Lake in California, as cited in the literature. Walker Lake filled rapidly with water between 5500 and 4500 years ago. The data published in this report was not produced under an approved Site Investigation Plan (SIP) or Study Plan (SP) and will not be used in the licensing process. 10 refs., 3 figs., 2 tabs

  12. EVALUATION OF WATER RETENTION CAPABILITY IN WETLANDS AT SMALL FOREST CATCHMENT

    Directory of Open Access Journals (Sweden)

    Daniel Liberacki

    2015-07-01

    Full Text Available The paper presents the results of researches carried out in the middle part of Pizza Zielonka forest complex. The aim was the evaluation of retention changes at wetlands and mid-forest ponds. The object of the study was the catchment of the Trojanka watercourse, considering from the origin to the cross-section of Zielonka Lake. The catchment is located in in the central part of the Wielkopolska region, approximatelly 20 km on the North-East of Poznań. The area of this forestall catchment is about 223 ha. In the paper an analysis of the results from three hydrological years was presented. The results of the years 1987 (wet year, 2003 (dry year and 2009 (medium year were analysed against meteorological conditions. Retention capacity in each wetlands, as well as the possibility of water retention in the Trojanka watercourse was calculated. The researches confirmed significant meteorological conditions influence the amount of retentioned water. The calculated capacity of retentioned water was 15 852 m3 considering the total area of wetland and swamp (8,58 ha and precipitation sum of 555 mm. 18% increase of water capacity was observed in wet year (1987 In this year the sum of precipitation was 100 mm higher than multiyear average sum. Meanwhile 62% decrease of water capacity was observed in dry year (2003, when the precipitation sum was 208 mm lower than multiyear average one.

  13. Predicting hydrological response to forest changes by simple statistical models: the selection of the best indicator of forest changes with a hydrological perspective

    Science.gov (United States)

    Ning, D.; Zhang, M.; Ren, S.; Hou, Y.; Yu, L.; Meng, Z.

    2017-01-01

    Forest plays an important role in hydrological cycle, and forest changes will inevitably affect runoff across multiple spatial scales. The selection of a suitable indicator for forest changes is essential for predicting forest-related hydrological response. This study used the Meijiang River, one of the headwaters of the Poyang Lake as an example to identify the best indicator of forest changes for predicting forest change-induced hydrological responses. Correlation analysis was conducted first to detect the relationships between monthly runoff and its predictive variables including antecedent monthly precipitation and indicators for forest changes (forest coverage, vegetation indices including EVI, NDVI, and NDWI), and by use of the identified predictive variables that were most correlated with monthly runoff, multiple linear regression models were then developed. The model with best performance identified in this study included two independent variables -antecedent monthly precipitation and NDWI. It indicates that NDWI is the best indicator of forest change in hydrological prediction while forest coverage, the most commonly used indicator of forest change is insignificantly related to monthly runoff. This highlights the use of vegetation index such as NDWI to indicate forest changes in hydrological studies. This study will provide us with an efficient way to quantify the hydrological impact of large-scale forest changes in the Meijiang River watershed, which is crucial for downstream water resource management and ecological protection in the Poyang Lake basin.

  14. Runoff curve numbers for 10 small forested watersheds in the mountains of the eastern United States

    Science.gov (United States)

    Negussie H. Tedela; Steven C. McCutcheon; Todd C. Rasmussen; Richard H. Hawkins; Wayne T. Swank; John L. Campbell; Mary Beth Adams; C. Rhett Jackson; Ernest W. Tollner

    2012-01-01

    Engineers and hydrologists use the curve number method to estimate runoff from rainfall for different land use and soil conditions; however, large uncertainties occur for estimates from forested watersheds. This investigation evaluates the accuracy and consistency of the method using rainfall-runoff series from 10 small forested-mountainous watersheds in the eastern...

  15. Small-scale structure and the Lyman-α forest baryon acoustic oscillation feature

    Science.gov (United States)

    Hirata, Christopher M.

    2018-02-01

    The baryon-acoustic oscillation (BAO) feature in the Lyman-α forest is a key probe of the cosmic expansion rate at redshifts z ˜ 2.5, well before dark energy is believed to have become significant. A key advantage of the BAO as a standard ruler is that it is a sharp feature and hence is more robust against broad-band systematic effects than other cosmological probes. However, if the Lyman-α forest transmission is sensitive to the initial streaming velocity of the baryons relative to the dark matter, then the BAO peak position can be shifted. Here we investigate this sensitivity using a suite of hydrodynamic simulations of small regions of the intergalactic medium with a range of box sizes and physics assumptions; each simulation starts from initial conditions at the kinematic decoupling era (z ˜ 1059), undergoes a discrete change from neutral gas to ionized gas thermal evolution at reionization (z ˜ 8), and is finally processed into a Lyman-α forest transmitted flux cube. Streaming velocities suppress small-scale structure, leading to less violent relaxation after reionization. The changes in the gas distribution and temperature-density relation at low redshift are more subtle, due to the convergent temperature evolution in the ionized phase. The change in the BAO scale is estimated to be of the order of 0.12 per cent at z = 2.5; some of the major uncertainties and avenues for future improvement are discussed. The predicted streaming velocity shift would be a subdominant but not negligible effect (of order 0.26σ) for the upcoming DESI Lyman-α forest survey, and exceeds the cosmic variance floor.

  16. SLAM-Aided Stem Mapping for Forest Inventory with Small-Footprint Mobile LiDAR

    Directory of Open Access Journals (Sweden)

    Jian Tang

    2015-12-01

    Full Text Available Accurately retrieving tree stem location distributions is a basic requirement for biomass estimation of forest inventory. Combining Inertial Measurement Units (IMU with Global Navigation Satellite Systems (GNSS is a commonly used positioning strategy in most Mobile Laser Scanning (MLS systems for accurate forest mapping. Coupled with a tactical or consumer grade IMU, GNSS offers a satisfactory solution in open forest environments, for which positioning accuracy better than one decimeter can be achieved. However, for such MLS systems, positioning in a mature and dense forest is still a challenging task because of the loss of GNSS signals attenuated by thick canopy. Most often laser scanning sensors in MLS systems are used for mapping and modelling rather than positioning. In this paper, we investigate a Simultaneous Localization and Mapping (SLAM-aided positioning solution with point clouds collected by a small-footprint LiDAR. Based on the field test data, we evaluate the potential of SLAM positioning and mapping in forest inventories. The results show that the positioning accuracy in the selected test field is improved by 38% compared to that of a traditional tactical grade IMU + GNSS positioning system in a mature forest environment and, as a result, we are able to produce a unambiguous tree distribution map.

  17. An Initial Analysis of LANDSAT-4 Thematic Mapper Data for the Discrimination of Agricultural, Forested Wetlands, and Urban Land Cover. [Poinsett County, Arkansas; and Reelfoot Lake and Union City, Tennessee

    Science.gov (United States)

    Quattrochi, D. A.

    1985-01-01

    The capabilities of TM data for discriminating land covers within three particular cultural and ecological realms was assessed. The agricultural investigation in Poinsett County, Arkansas illustrates that TM data can successfully be used to discriminate a variety of crop cover types within the study area. The single-date TM classification produced results that were significantly better than those developed from multitemporal MSS data. For the Reelfoot Lake area of Tennessee TM data, processed using unsupervised signature development techniques, produced a detailed classification of forested wetlands with excellent accuracy. Even in a small city of approximately 15,000 people (Union City, Tennessee). TM data can successfully be used to spectrally distinguish specific urban classes. Furthermore, the principal components analysis evaluation of the data shows that through photointerpretation, it is possible to distinguish individual buildings and roof responses with the TM.

  18. Lake Lysevatten - A study of liming and reacidification effects in a forest lake ecosystem in southwestern Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, B.I.; Hultberg, H.

    1997-02-01

    Long-term monitoring (1973 to 1987) of acidification and liming effects to a lake ecosystem is reported in this study. The liming intervention of Lake Lysevatten in spring 1974 resulted in neutralisation of lake water and positive alkalinity. Invasion and population expansion of new species started and proceeded for several years. Following the neutralisation Sphagnum was almost eradicated. The restocking with fish changed the predator-prey interactions, and the community composition gradually approached what would be expected to be within the normal range for an unacidified lake. Early signs of reacidification were: The appearance of filamentous algae; Decreased condition of Brown trout (Salmo trutta) caused by increased aluminium concentrations in connection with an acid event; Enhanced growth of Sphagnum surviving on profundal bottoms. Progressive reacidification to Ph 5.0 resulted in accelerated growth of Mougeotia reaching nuisance level. If implemented, liming should be prolonged by reinterventions before alkalinity and pH decrease to much. A stable circumneutral pH is a prerequisite to provide the timescale necessary for invasion and population growth of organisms with low dispersal capacity. Furthermore, the most sensitive organisms will be adversely affected already at pH-values around six. Extensive reacidification should by all means be prevented as development of a destabilized lake community could react rather unpredictably. 168 refs, 80 figs, 26 tabs

  19. Influence of lake surface area and total phosphorus on annual bluegill growth in small impoundments of central Georgia

    Science.gov (United States)

    Jennings, Cecil A.; Sundmark, Aaron P.

    2017-01-01

    The relationships between environmental variables and the growth rates of fishes are important and rapidly expanding topics in fisheries ecology. We used an informationtheoretic approach to evaluate the influence of lake surface area and total phosphorus on the age-specific growth rates of Lepomis macrochirus (Bluegill) in 6 small impoundments in central Georgia. We used model averaging to create composite models and determine the relative importance of the variables within each model. Results indicated that surface area was the most important factor in the models predicting growth of Bluegills aged 1–4 years; total phosphorus was also an important predictor for the same age-classes. These results suggest that managers can use water quality and lake morphometry variables to create predictive models specific to their waterbody or region to help develop lake-specific management plans that select for and optimize local-level habitat factors for enhancing Bluegill growth.

  20. How to estimate carbon sequestration on small forest tracts estimate carbon sequestration on small forest tracts

    Science.gov (United States)

    Coeli M. Hoover; Richard A. Birdsey; Linda S. Heath; Susan L. Stout

    2000-01-01

    International climate change agreements may allow carbon stored as a result of afforestation and reforestation to be used to offset CO2 emissions. Monitoring the carbon sequestered or released through forest management activities thus becomes important. Estimating forest carbon storage is feasible even for nonindustrial private forestland (NIPF)...

  1. Beech Range Extension and Vegetation History: Pollen Stratigraphy of Two Wisconsin Lakes.

    Science.gov (United States)

    Webb, Sara L

    1987-12-01

    The pollen stratigraphy of two small lakes in eastern Wisconsin (Radtke Lake, Washington county, and Gass Lake, Manitowoc County) records the Holocene (past 10 000 yr) spread of beech (Fagus grandifolia: Fagaceae). Radiocarbon dates were obtained for the oldest stratigraphic levels at which beech pollen appeared consistently in amounts > 0.5% of terrestrial pollen. A spatially continuous pattern of beech expansion from the north was ruled out, because beech trees grew in Wisconsin by 6000 BP, 2000 yr before adjacent populations were established to the north. Alternative geographic patterns of speed (from the south or east) were spatially discontinuous, requiring seed dispersal distances of perhaps 25-130 km. That beechnuts could be dispersed across such distances suggests (1) the involvement of Blue Jays, Passenger Pigeons, or other vertebrates, and (2) a capacity for reaching climatically controlled range limits, given sufficient time despite such discontinuities in habitat. A lag 1000-2000 yr between the establishment of source populations in Michigan and Indiana and the appearance of beech in Wisconsin suggests that low-probability dispersal events were involved and that dispersal constraints limited the range of beech during this time, although climatic and edaphic explanations for the lag cannot be ruled out. Pollen data from the two sites reveal other features of vegetation history in eastern Wisconsin: an open Picea-Fraxinus woodland prior to 11 000 BP; sequence of Picea, Abies, Betula, and then Pinus forests between 11 000 and 7500 BP; the establishment of a coniferous/deciduous forest ecotone ("tension zone") ° 7000 BP in this region; and the presence of Quercus-dominanted deciduous forests from 7000 BP until 110 BP (time of Euro-American settlement), a period punctuated by a gradual decrease in Ulmus populations (° 4500 and 5700 BP at the two sites) and by an increase in mesophytic tree abundance at the expense of Quercus after 3500 BP. © 1987 by the

  2. Ecology in Small Aquatic Ecosystems

    DEFF Research Database (Denmark)

    Andersen, Mikkel René

    Small ecosystems are many-fold more abundant than their larger counterparts. Both on regional and global scale small lakes outnumber medium and large lakes and account for a much larger surface area. Small streams are also far more common than rivers. Despite their abundance small ecosystems are ...

  3. Comparison of small-footprint discrete return and full waveform airborne lidar data for estimating multiple forest variables

    OpenAIRE

    Sumnall, Matthew J.; Hill, Ross A.; Hinsley, Shelley A.

    2016-01-01

    The quantification of forest ecosystems is important for a variety of purposes, including the assessment of wildlife habitat, nutrient cycles, timber yield and fire propagation. This research assesses the estimation of forest structure, composition and deadwood variables from small-footprint airborne lidar data, both discrete return (DR) and full waveform (FW), acquired under leaf-on and leaf-off conditions. The field site, in the New Forest, UK, includes managed plantation and ancient, se...

  4. Conifer density within lake catchments predicts fish mercury concentrations in remote subalpine lakes

    Science.gov (United States)

    Eagles-Smith, Collin A.; Herring, Garth; Johnson, Branden L.; Graw, Rick

    2016-01-01

    Remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited mercury through freshwater food webs, as well as for evaluating the relative importance of mercury loading versus landscape influences on mercury bioaccumulation. The increase in mercury deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in mercury emissions may propagate to changes in Hg bioaccumulation and ecological risk. We evaluated mercury concentrations in resident fish from 28 high-elevation, sub-alpine lakes in the Pacific Northwest region of the United States. Fish total mercury (THg) concentrations ranged from 4 to 438 ng/g wet weight, with a geometric mean concentration (±standard error) of 43 ± 2 ng/g ww. Fish THg concentrations were negatively correlated with relative condition factor, indicating that faster growing fish that are in better condition have lower THg concentrations. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. We used a hierarchal statistical approach to evaluate the relative importance of physiological, limnological, and catchment drivers of fish Hg concentrations. Our top statistical model explained 87% of the variability in fish THg concentrations among lakes with four key landscape and limnological variables: catchment conifer density (basal area of conifers within a lake's catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. Conifer density within a lake's catchment was the most important variable explaining fish THg concentrations across lakes, with THg concentrations differing by more than 400 percent across the forest density spectrum. These results illustrate the importance of landscape characteristics in controlling mercury bioaccumulation in fish.

  5. Comparing Effects of Lake- and Watershed-Scale Influences on Communities of Aquatic Invertebrates in Shallow Lakes

    Science.gov (United States)

    Hanson, Mark A.; Herwig, Brian R.; Zimmer, Kyle D.; Fieberg, John; Vaughn, Sean R.; Wright, Robert G.; Younk, Jerry A.

    2012-01-01

    Constraints on lake communities are complex and are usually studied by using limited combinations of variables derived from measurements within or adjacent to study waters. While informative, results often provide limited insight about magnitude of simultaneous influences operating at multiple scales, such as lake- vs. watershed-scale. To formulate comparisons of such contrasting influences, we explored factors controlling the abundance of predominant aquatic invertebrates in 75 shallow lakes in western Minnesota, USA. Using robust regression techniques, we modeled relative abundance of Amphipoda, small and large cladocera, Corixidae, aquatic Diptera, and an aggregate taxon that combined Ephemeroptera-Trichoptera-Odonata (ETO) in response to lake- and watershed-scale characteristics. Predictor variables included fish and submerged plant abundance, linear distance to the nearest wetland or lake, watershed size, and proportion of the watershed in agricultural production. Among-lake variability in invertebrate abundance was more often explained by lake-scale predictors than by variables based on watershed characteristics. For example, we identified significant associations between fish presence and community type and abundance of small and large cladocera, Amphipoda, Diptera, and ETO. Abundance of Amphipoda, Diptera, and Corixidae were also positively correlated with submerged plant abundance. We observed no associations between lake-watershed variables and abundance of our invertebrate taxa. Broadly, our results seem to indicate preeminence of lake-level influences on aquatic invertebrates in shallow lakes, but historical land-use legacies may mask important relationships. PMID:22970275

  6. The Contribution of Multiple Use Forest Management to Small Farmers’ Annual Incomes in the Eastern Amazon

    Directory of Open Access Journals (Sweden)

    Plinio Sist

    2014-06-01

    Full Text Available Small-scale farmers in the Brazilian Amazon collectively hold tenure over more than 12 million ha of permanent forest reserves, as required by the Forest Code. The trade-off between forest conservation and other land uses entails opportunity costs for them and for the country, which have not been sufficiently studied. We assessed the potential income generated by multiple use forest management for farmers and compared it to the income potentially derived from six other agricultural land uses. Income from the forest was from (i logging, carried out by a logging company in partnership with farmers’ associations; and (ii harvesting the seeds of Carapa guianensis (local name andiroba for the production of oil. We then compared the income generated by multiple-use forest management with the income from different types of agrarian systems. According to our calculations in this study, the mean annual economic benefits from multiple forest use are the same as the least productive agrarian system, but only 25% of the annual income generated by the most productive system. Although the income generated by logging may be considered low when calculated on an annual basis and compared to incomes generated by agriculture, the one-time payment after logging is significant (US$5,800 to US$33,508 and could be used to implement more intensive and productive cropping systems such as planting black pepper. The income from forest management could also be used to establish permanent fields in deforested areas for highly productive annual crops using conservation agriculture techniques. These techniques are alternatives to the traditional land use based on periodic clearing of the forest. Nevertheless, the shift in current practices towards adoption of more sustainable conservation agriculture techniques will also require the technical and legal support of the State to help small farmers apply these alternatives, which aim to integrate forest management in

  7. 77 FR 33230 - Notice of Intent To Prepare an Environmental Impact Statement for Proposed Strategies for Lake...

    Science.gov (United States)

    2012-06-05

    ... reduce non-native lake trout abundance in Flathead Lake to benefit native fish populations in Flathead... Forest Service, US Geological Survey, local fishing guides and anglers, Trout Unlimited, University of... action (maintain the status quo of lake trout harvest from general harvest and fishing contests); (2...

  8. Environmental research programme. Ecological research. Annual report 1994. Urban-industrial landscapes, forests, agricultural landscapes, river and lake landscapes, terrestrial ecosystem research, environmental pollution and health

    International Nuclear Information System (INIS)

    1995-01-01

    In the annual report 1994 of the Federal Ministry of Research and Technology, the points of emphasis of the ecological research programme and their financing are discussed. The individual projects in the following subject areas are described in detail: urban-industrial landscapes, forests, agricultural landscapes, river and lake landscapes, other ecosystems and landscapes, terrestrial ecosystem research, environmental pollution and human health and cross-sectional activities in ecological research. (vhe) [de

  9. Total and methyl mercury concentrations and fluxes from small boreal forest catchments in Finland

    International Nuclear Information System (INIS)

    Porvari, Petri; Verta, Matti

    2003-01-01

    Peatlands have higher methyl mercury output than uplands. - Total mercury (TotHg) and methyl mercury (MeHg) concentrations were studied in runoff from eight small (0.02-1.3 km 2 ) boreal forest catchments (mineral soil and peatland) during 1990-1995. Runoff waters were extremely humic (TOC 7-70 mg l -1 ). TotHg concentrations varied between 0.84 and 24 ng l -1 and MeHg between 0.03 and 3.8 ng l -1 . TotHg fluxes from catchments ranged from 0.92 to 1.8 g km -2 a -1 , and MeHg fluxes from 0.03 to 0.33 g km -2 a -1 . TotHg concentrations and output fluxes measured in runoff water from small forest catchments in Finland were comparable with those measured in other boreal regions. By contrast, MeHg concentrations were generally higher. Estimates for MeHg output fluxes in this study were comparable at sites with forests and wetlands in Sweden and North America, but clearly higher than those measured at upland or agricultural sites in other studies. Peatland catchments released more MeHg than pure mineral soil or mineral soil catchments with minor area of peatland

  10. The small barbs Barbus humilis and B. trispilopleura of Lake Tana (Ethiopia): Are they ecotypes of the same species?

    NARCIS (Netherlands)

    Dejen, E.; Rutjes, H.A.; Graaf, de M.; Nagelkerke, L.A.J.; Osse, J.W.M.; Sibbing, F.A.

    2002-01-01

    Four species of ‘small barbs’ (Barbus, subgenus Enteromius Cope, 1869) are known from Lake Tana, isolated in the Ethiopian highlands: B. humilis, B. trispilopleura, B. pleurogramma (all Boulenger, 1902) and B. tanapelagius de Graaf, 2000. However, only three species appear valid from cluster

  11. Analysis And Assessment Of Forest Cover Change For The State Of Wisconsin

    Science.gov (United States)

    Perry, C. H.; Nelson, M. D.; Stueve, K.; Gormanson, D.

    2010-12-01

    The Forest Inventory and Analysis (FIA) program of the USDA Forest Service is charged with documenting the status and trends of forest resources of the United States. Since the 1930s, FIA has implemented an intensive field campaign that collects measurements on plots distributed across all ownerships, historically completing analyses which include estimates of forest area, volume, mortality, growth, removals, and timber products output in various ways, such as by ownership, region, or State. Originally a periodic inventory, FIA has been measuring plots on an annual basis since the passage of the Agriculture Research, Extension and Education Reform Act of 1998 (Farm Bill). The resulting change in sampling design and intensity presents challenges to establishing baseline and measuring changes in forest area and biomass. A project jointly sponsored by the Forest Service and the National Aeronautics and Space Agency (NASA) titled “Integrating Landscape-scale Forest Measurements with Remote Sensing and Ecosystem Models to Improve Carbon Management Decisions” seeks to improve estimates of landscape- and continental-scale carbon dynamics and causes of change for North American forest land, and to use this information to support land management decisions. Specifically, we are developing and applying methods to scale up intensive biomass and carbon measurements from the field campaign to larger land management areas while simultaneously estimating change in the above-ground forest carbon stocks; the State of Wisconsin is being used as the testbed for this large-scale integration remote sensing with field measurements. Once defined, the temporal and spatial patterns of forest resources by watershed for Lake Superior and Lake Michigan outputs are being integrated into water quality assessments for the Great Lakes.

  12. Scleroderris Canker in the Lake States - A Situation Report, 1968

    Science.gov (United States)

    Darroll D. Skilling; James T. O' Brian

    1969-01-01

    The history of Scleroderris canker in the Lake States Region is reviewed. U.S.D.A. Forest Service studies on the distribution, degree of infection, rate of spread, and general biology of the disease organism are described. On National Forest land in Upper Michigan and northern Wisconsin, where the disease is most serious, 66 percent of the red pine plantations and 88...

  13. THE WATER QUALITY FROM SAINT ANA LAKE

    Directory of Open Access Journals (Sweden)

    M.VIGH

    2013-03-01

    Full Text Available Inside the Ciomad Massive appears a unique lake in Romania, with an exclusive precipitations alimentation regime. The lake’s origin and the morphometric elements, together with the touristic activity, determine the water’s quality and characteristics. Water status evaluation was realized using random samples taken between the years 2005 and 2010. Qualitative parameters indicate the existence of a clear water lake, belonging to ultra-oligotrophic faze. This is because the crater is covered with forest and the surface erosion is very poor. Also the aquatic vegetation is rare. From all analyzed indicators, only ammonium and total mineral nitrogen have higher values during last years. In the future, the lake needs a higher protection against water quality degradation.

  14. Function, Design, and Establishment of Riparian Forest Buffers: A Review

    OpenAIRE

    Klapproth, Julia Caldwell

    1999-01-01

    Through the interaction of their soils, hydrology, and biotic communities, riparian forests protect and improve water quality, provide habitat for plants and animals, support aquatic communities, and provide many benefits to humans. Virginia, along with other states in the Chesapeake Bay region, has recognized the importance of riparian forests by implementing a plan to restore forested buffers along streams, rivers, and lakes. This project reviews selected literature on riparian forest bu...

  15. LBA-ECO ND-02 Secondary Forest Small Stem, Non-Woody Biomass, Para, Brazil: 1999-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports biomass from small stems and non-woody vegetation measured from 1999 to 2005 in plots of a secondary-growth forest fertilization experiment....

  16. LBA-ECO ND-02 Secondary Forest Small Stem, Non-Woody Biomass, Para, Brazil: 1999-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports biomass from small stems and non-woody vegetation measured from 1999 to 2005 in plots of a secondary-growth forest fertilization...

  17. Modeling lake trophic state: a random forest approach

    Science.gov (United States)

    Productivity of lentic ecosystems has been well studied and it is widely accepted that as nutrient inputs increase, productivity increases and lakes transition from low trophic state (e.g. oligotrophic) to higher trophic states (e.g. eutrophic). These broad trophic state classi...

  18. Application of a Spectral Wave Model to Assess Breakwater Configurations at a Small Craft Harbour on Lake Ontario

    Directory of Open Access Journals (Sweden)

    Amelia H. Cooper

    2016-08-01

    Full Text Available A surface wave model using three nested grids is applied to the eastern end of Lake Ontario to investigate wave propagation from an open lake environment to a small craft harbour protected by a breakwater. The Simulating WAves Nearshore (SWAN spectral wave model, coupled with the Delft3D hydrodynamic model, is applied to simulate a series of storms in November, 2013. The model results are compared to observations from two pressure sensors, and used to quantify wave properties around existing and future breakwaters to evaluate the bulk changes to the harbour configuration. Overall, the results indicate that the rubblemound breakwater reduces wave heights in the existing harbour by 63% compared to no breakwater, and that the addition of a surface breakwater extension could reduce wave heights by an additional 54%. Wave height attenuation was found to be highly dependent on the incident wave direction relative to breakwater orientation. The spectral wave model is useful for simulating wave transformation for broad directional spectra in wind-sea conditions over large scales to semi-protected areas such as small craft harbours.

  19. Water quality assessment in a shallow lake used for tourism

    Directory of Open Access Journals (Sweden)

    Dembowska Ewa A.

    2015-12-01

    Full Text Available The routine evaluation of water quality is limited to lakes with the largest area. In Poland, only lakes with an area exceeding 50 hectares are monitored by the State Environmental Monitoring System. For many local communities, however, small lakes are more important. This applies mainly to areas with a small number of lakes, where even the smallest lakes are used for various purposes. This paper presents the results of phytoplankton analysis in a small and shallow lake used for recreation. The study was conducted at three sites located in different parts of the lake. A total of 122 algae taxa were identified in the phytoplankton, mainly diatoms and green algae. The most constant taxa in the lake were: Stephanodiscus hantzschii, Desmodesmus communis, Pediastrum tetras and Crucigenia tetrapedia. The average phytoplankton biomass was 37 mg l−1. The maximum biomass, almost 140 mg dm−3, was recorded in late July at the site located near the beach. At that time, there was a massive cyanobacterial bloom composed of Microcystis wesenbergii and Aphanizomenon issatschenkoi. Based on these studies, the lake should be classified as hypertrophic with bad ecological status. This lake should not be used for recreational purposes in the current state.

  20. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  1. Small habitat size and isolation can promote species richness: second-order effects on biodiversity in shallow lakes and ponds

    NARCIS (Netherlands)

    Scheffer, M.; Van Geest, G.J.; Zimmer, K.; Jeppesen, E.; Søndergaard, M.; Butler, M.G.; Hanson, M.A.; Declerck, S.A.J.; De Meester, L.

    2006-01-01

    Contemporary ecological landscape planning is often based on the assumption that small isolated habitat patches sustain relatively few species. Here, we suggest that for shallow lakes and ponds, the opposite can be true for some groups of organisms. Fish communities tend to be poor or even absent in

  2. Effects of liming and ash recycling on the outflow of mercury from forest soils - a theoretical study

    International Nuclear Information System (INIS)

    Andersson, Arne; Nilsson, Ingvar

    1994-01-01

    In this report, a theoretical review is made of the probable effects that spreading of lime and woodash in forests will have on the turnover of mercury in soil and on the outflow of mercury into water systems. As a result of historic emissions of mercury into the atmosphere, a large proportion of Swedish forest land has significantly increased concentrations of mercury, which is gradually leaching into lakes and watercourses. If an increased application of lime or woodash to forest soils were to result in a major change in the outflow of mercury, it could in time have a considerable effect on the mercury concentrations in lake fish. The fish in a large number of lakes in the southern part of Sweden already have mercury concentrations which are so high as to make them unsuitable for use as food. In conclusion, the theoretical assessment indicates in general that any effects on the mercury situation in lakes as a result of liming or woodash treatment of forest land are marginal or towards the positive side. It is not likely that these treatments increases the outflow of organic matter from soil. Any worsening of the mercury situation in lakes and watercourses will therefore hardly be the result of soil changes, but rather of processes in lakes and streams. Most of the evidence, however suggests that liming/ash treatment has predominantly positive effects with regard to the lake processes that control mercury levels in fish. At this juncture, available experience indicates that the mercury situation in the environment is in no way a decisive factor in determining where and how lime or ash should be applied to forest land. 64 refs, 2 figs

  3. Computer-aided classification of forest cover types from small scale aerial photography

    Science.gov (United States)

    Bliss, John C.; Bonnicksen, Thomas M.; Mace, Thomas H.

    1980-11-01

    The US National Park Service must map forest cover types over extensive areas in order to fulfill its goal of maintaining or reconstructing presettlement vegetation within national parks and monuments. Furthermore, such cover type maps must be updated on a regular basis to document vegetation changes. Computer-aided classification of small scale aerial photography is a promising technique for generating forest cover type maps efficiently and inexpensively. In this study, seven cover types were classified with an overall accuracy of 62 percent from a reproduction of a 1∶120,000 color infrared transparency of a conifer-hardwood forest. The results were encouraging, given the degraded quality of the photograph and the fact that features were not centered, as well as the lack of information on lens vignetting characteristics to make corrections. Suggestions are made for resolving these problems in future research and applications. In addition, it is hypothesized that the overall accuracy is artificially low because the computer-aided classification more accurately portrayed the intermixing of cover types than the hand-drawn maps to which it was compared.

  4. BATHYMETRIC STUDY OF WADI EL-RAYAN LAKES, EGYPT

    Directory of Open Access Journals (Sweden)

    Radwan Gad Elrab ABD ELLAH

    2016-12-01

    Full Text Available Bathymetry is a technique of measuring depths to determine the morphometry of water bodies. The derivation of bathymetry from the surveys is one of the basic researches of the aquatic environment, which has several practical implications to on the lake environment and it's monitoring. Wadi El-Rayan, as Ramsar site, is a very important wetland, in Egypt, as a reservoir for agricultural drainage water, fisheries and tourism. The Lakes are man-made basins in the Fayoum depression. Wadi El-Rayan Lakes are two reservoirs (upper Lake and Lower Lake, at different elevations. The Upper Lake is classified as open basin, while the Lower Lake is a closed basin, with no significant obvious water outflow. During recent decades, human impact on Wadi El-Rayan Lakes has increased due to intensification of agriculture and fish farming. Analyses of bathyemtric plans from 1996, 2010 and 2016 showed, the differences between morphometric parameters of the Upper Lake were generally small, while the Lower Lake changes are obvious at the three periods. The small fluctuate, in the features of Upper Lake is due to the water balance between the water inflow and water. The Lower Lake has faced extreme water loss through last twenty years is due to the agricultural lands and fish farms extended in the depression. The Upper Lake is rich in Lakeshores macrophyets, while decline the water plants in the Lower Lake. With low water levels, in the Lower Lake, the future continuity of the Lake system is in jeopardy

  5. Examining the utility of satellite-based wind sheltering estimates for lake hydrodynamic modeling

    Science.gov (United States)

    Van Den Hoek, Jamon; Read, Jordan S.; Winslow, Luke A.; Montesano, Paul; Markfort, Corey D.

    2015-01-01

    Satellite-based measurements of vegetation canopy structure have been in common use for the last decade but have never been used to estimate canopy's impact on wind sheltering of individual lakes. Wind sheltering is caused by slower winds in the wake of topography and shoreline obstacles (e.g. forest canopy) and influences heat loss and the flux of wind-driven mixing energy into lakes, which control lake temperatures and indirectly structure lake ecosystem processes, including carbon cycling and thermal habitat partitioning. Lakeshore wind sheltering has often been parameterized by lake surface area but such empirical relationships are only based on forested lakeshores and overlook the contributions of local land cover and terrain to wind sheltering. This study is the first to examine the utility of satellite imagery-derived broad-scale estimates of wind sheltering across a diversity of land covers. Using 30 m spatial resolution ASTER GDEM2 elevation data, the mean sheltering height, hs, being the combination of local topographic rise and canopy height above the lake surface, is calculated within 100 m-wide buffers surrounding 76,000 lakes in the U.S. state of Wisconsin. Uncertainty of GDEM2-derived hs was compared to SRTM-, high-resolution G-LiHT lidar-, and ICESat-derived estimates of hs, respective influences of land cover type and buffer width on hsare examined; and the effect of including satellite-based hs on the accuracy of a statewide lake hydrodynamic model was discussed. Though GDEM2 hs uncertainty was comparable to or better than other satellite-based measures of hs, its higher spatial resolution and broader spatial coverage allowed more lakes to be included in modeling efforts. GDEM2 was shown to offer superior utility for estimating hs compared to other satellite-derived data, but was limited by its consistent underestimation of hs, inability to detect within-buffer hs variability, and differing accuracy across land cover types. Nonetheless

  6. Water resources of the Lake Erie shore region in Pennsylvania

    Science.gov (United States)

    Mangan, John William; Van Tuyl, Donald W.; White, Walter F.

    1952-01-01

    An abundant supply of water is available to the Lake Erie Shore region in Pennsylvania. Lake i£rie furnishes an almost inexhaustible supply of water of satisfactory chemical quality. Small quantities of water are available from small streams in the area and from the ground. A satisfactory water supply is one of the factors that affect the economic growth of a region. Cities and towns must have adequate amounts of pure water for human consumption. Industries must have suitable water ih sufficient quantities for all purposes. In order to assure. success and economy, the development of water resources should be based on adequate knowledge of the quantity and quality of the water. As a nation, we can not afford to run the risk of dissipating our resources, especially in times of national emergency, by building projects that are not founded on sound engineering and adequate water-resources information. The purpose of this report is to summarize and interpret all available water-resources information for the Lake Erie Shore region in Pennsylvania. The report will be useful for initial guidance in the location or expansion of water facilities for defense and nondefense industries and the municipalities upon which they are dependent. It will also be useful in evaluating the adequacy of the Geological Survey's part of the basic research necessary to plan the orderly development of the water resources of the Lake Erie Shore region. Most of the data contained inthis report have been obtained'by the U. S. Geological Survey in cooperation with the Pennsylvania Department of Forests and Waters, the Pennsylvania Department of Internal Affairs, and the Pennsylvania State Planning Board, Department of Commerce. The Pennsylv~nia Department of Health furnished information on water pollution. The report was prepared in the Water Resources Division of the U. S. Geological Survey b:y John W. Mangan (Surface Water). Donald W. VanTuyl (Ground Water). and Walter F. White, Jr. (Quality of

  7. Ecological Health and Water Quality Assessments in Big Creek Lake, AL

    Science.gov (United States)

    Childs, L. M.; Frey, J. W.; Jones, J. B.; Maki, A. E.; Brozen, M. W.; Malik, S.; Allain, M.; Mitchell, B.; Batina, M.; Brooks, A. O.

    2008-12-01

    Big Creek Lake (aka J.B. Converse Reservoir) serves as the water supply for the majority of residents in Mobile County, Alabama. The area surrounding the reservoir serves as a gopher tortoise mitigation bank and is protected from further development, however, impacts from previous disasters and construction have greatly impacted the Big Creek Lake area. The Escatawpa Watershed drains into the lake, and of the seven drainage streams, three have received a 303 (d) (impaired water bodies) designation in the past. In the adjacent ecosystem, the forest is experiencing major stress from drought and pine bark beetle infestations. Various agencies are using control methods such as pesticide treatment to eradicate the beetles. There are many concerns about these control methods and the run-off into the ecosystem. In addition to pesticide control methods, the Highway 98 construction projects cross the north area of the lake. The community has expressed concern about both direct and indirect impacts of these construction projects on the lake. This project addresses concerns about water quality, increasing drought in the Southeastern U.S., forest health as it relates to vegetation stress, and state and federal needs for improved assessment methods supported by remotely sensed data to determine coastal forest susceptibility to pine bark beetles. Landsat TM, ASTER, MODIS, and EO-1/ALI imagery was employed in Normalized Difference Vegetation Index (NDVI) and Normalized Difference Moisture Index (NDMI), as well as to detect concentration of suspended solids, chlorophyll and water turbidity. This study utilizes NASA Earth Observation Systems to determine how environmental conditions and human activity relate to pine tree stress and the onset of pine beetle invasion, as well as relate current water quality data to community concerns and gain a better understanding of human impacts upon water resources.

  8. Brook trout (Salvelinus fontinalis extinction in small boreal lakes revealed by ephippia pigmentation: a preliminary analysis

    Directory of Open Access Journals (Sweden)

    Alexandre Bérubé Tellier

    2016-12-01

    Full Text Available Ephippium pigmentation is a plastic trait which can be related to a trade-off between visual predation pressure and better protection of cladoceran eggs against different types of stress. Experimental studies showed that planktivorous fish exert a greater predation pressure on individuals carrying darker ephippia, but little is known about the variation of ephippium pigmentation along gradients of fish predation pressure in natural conditions. For this study, our experimental design included four small boreal lakes with known fish assemblages. Two of the lakes have viable brook trout (Salvelinus fontinalis populations, whereas the other two lakes experienced brook trout extinctions during the 20th century. Cladoceran ephippia were extracted from sediment cores at layers corresponding to the documented post- extinction phase (1990's and from an older layer (1950's for which the brook trout population status is not known precisely. Our first objective was to determine whether brook trout extinction has a direct effect on both ephippium pigmentation and size. Our second objective was to give a preliminary assessment of the status of brook trout populations in the 1950's by comparing the variation in ephippia traits measured from this layer to those measured in the 1990's, for which the extinction patterns are well known. Cost-effective image analysis was used to assess variation in pigmentation levels in ephippia. This approach provided a proxy for the amount of melanin invested in each ephippium analysed. Our study clearly shows that ephippium pigmentation may represent a better indicator of the presence of fish predators than ephippium size, a trait that showed a less clear pattern of variation between lakes with and without fish. For the 1990's period, ephippia from fishless lakes were darker and showed a slight tendency to be larger than ephippia from lakes with brook trout. However, no clear differences in either ephippium size or pigmentation

  9. Diversity of Mat-Forming Fungi in Relation to Soil Properties, Disturbance, and Forest Ecotype at Crater Lake National Park, Oregon, USA

    Directory of Open Access Journals (Sweden)

    James M. Trappe

    2012-04-01

    Full Text Available In forest ecosystems, fungal mats are functionally important in nutrient and water uptake in litter and wood decomposition processes, in carbon resource allocation, soil weathering and in cycling of soil resources. Fungal mats can occur abundantly in forests and are widely distributed globally. We sampled ponderosa pine/white fir and mountain hemlock/noble fir communities at Crater Lake National Park for mat-forming soil fungi. Fungus collections were identified by DNA sequencing. Thirty-eight mat-forming genotypes were identified; members of the five most common genera (Gautieria, Lepiota, Piloderma, Ramaria, and Rhizopogon comprised 67% of all collections. The mycorrhizal genera Alpova and Lactarius are newly identified as ectomycorrhizal mat-forming taxa, as are the saprotrophic genera Flavoscypha, Gastropila, Lepiota and Xenasmatella. Twelve typical mat forms are illustrated, representing both ectomycorrhizal and saprotrophic fungi that were found. Abundance of fungal mats was correlated with higher soil carbon to nitrogen ratios, fine woody debris and needle litter mass in both forest ecotypes. Definitions of fungal mats are discussed, along with some of the challenges in defining what comprises a fungal “mat”.

  10. Soil erosion and sedimentation rates in a small eutrophic lake in southern Chile estimated by 210Pb isotope analysis

    International Nuclear Information System (INIS)

    Cisternas, M.; Urrutia, R.; Araneda, A.; Debels, P.; Rios, F.

    1999-01-01

    The purpose of this research is to study the effects of historical land use patterns on soil erosion within the San Pedro Lake watershed (Concepcion, VIII Region, Chile). To this end, a geochronological reconstruction of the last 50 years was accomplished by 210 Pb isotope and photo-interpretation analysis through the use of GIS. The erosion rate has varied from 0.40 t ha -1 y -1 in 1955 to 0.86 t ha -1 y -1 in 1994. The decrease in native forest was closely coupled with the increase in exotic forestry. The Total Change, meaning the land use change without considering each typology, shows a constant trend indicating a greater degree of anthropogenic intervention. As opposed to the expected, there is no relationship between land use typologies and erosion rates, however it is possible to recognise some degree of dependency between Total Change and erosion values. It is concluded that over the last 50 years the soil erosion processes in the San Pedro Lake watershed may have been more regulated more by land use changes than by land use typologies themselves. (author)

  11. Contents of some heavy metals in plants from Saginaw Bay (Lake Huron) and some small lakes in wilderness areas of Michigan's Upper Peninsula as analyzed by neutron activation analysis

    International Nuclear Information System (INIS)

    Wells, J.R.; Kaufman, P.B.; Jones, J.D.; Estabrook, G.F.; Ghosheh, N.S.; Michigan Univ., Ann Arbor; Eastern Michigan University, Ypsilanti

    1982-01-01

    The highest concentrations of heavy metals occured in plants collected near the mouth of the Saginaw River. The alga, Cladophora sp., and the flowering plant, Typha augustifolia (cat-tail), are notable for the high concentration of heavy metals. In addition, several other species that were sampled from small lakes in Michigan's Upper Peninsula contained higher concentrations of certain metals (Ba, Cr, Rb) than from any samples obtained from Saginaw Bay. Different organs of the same species, or of the same plant, such as cut-tail, vary widely in concentrations of the same element. A computer-derived analysis of our data is presented, and the implications of our results as they relate to pollution by heavy metals in fresh-water lakes is discussed. (author)

  12. VT Northern Forest Lands - Lakes and Ponds area polygons

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) These data identify shorelines of lakes and ponds ten (10) acres and larger. The shorelines are classified according to their development status....

  13. VT Northern Forest Lands - Lakes and Ponds boundary lines

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) These data identify shorelines of lakes and ponds ten (10) acres and larger. The shorelines are classified according to their development status....

  14. A Bayesian Belief Network approach to assess the potential of non wood forest products for small scale forest owners

    Science.gov (United States)

    Vacik, Harald; Huber, Patrick; Hujala, Teppo; Kurtilla, Mikko; Wolfslehner, Bernhard

    2015-04-01

    It is an integral element of the European understanding of sustainable forest management to foster the design and marketing of forest products, non-wood forest products (NWFPs) and services that go beyond the production of timber. Despite the relevance of NWFPs in Europe, forest management and planning methods have been traditionally tailored towards wood and wood products, because most forest management models and silviculture techniques were developed to ensure a sustained production of timber. Although several approaches exist which explicitly consider NWFPs as management objectives in forest planning, specific models are needed for the assessment of their production potential in different environmental contexts and for different management regimes. Empirical data supporting a comprehensive assessment of the potential of NWFPs are rare, thus making development of statistical models particularly problematic. However, the complex causal relationships between the sustained production of NWFPs, the available ecological resources, as well as the organizational and the market potential of forest management regimes are well suited for knowledge-based expert models. Bayesian belief networks (BBNs) are a kind of probabilistic graphical model that have become very popular to practitioners and scientists mainly due to the powerful probability theory involved, which makes BBNs suitable to deal with a wide range of environmental problems. In this contribution we present the development of a Bayesian belief network to assess the potential of NWFPs for small scale forest owners. A three stage iterative process with stakeholder and expert participation was used to develop the Bayesian Network within the frame of the StarTree Project. The group of participants varied in the stages of the modelling process. A core team, consisting of one technical expert and two domain experts was responsible for the entire modelling process as well as for the first prototype of the network

  15. Quantifying small-scale spatio-temporal variability of snow stratigraphy in forests based on high-resolution snow penetrometry

    Science.gov (United States)

    Teich, M.; Hagenmuller, P.; Bebi, P.; Jenkins, M. J.; Giunta, A. D.; Schneebeli, M.

    2017-12-01

    Snow stratigraphy, the characteristic layering within a seasonal snowpack, has important implications for snow remote sensing, hydrology and avalanches. Forests modify snowpack properties through interception, wind speed reduction, and changes to the energy balance. The lack of snowpack observations in forests limits our ability to understand the evolution of snow stratigraphy and its spatio-temporal variability as a function of forest structure and to observe snowpack response to changes in forest cover. We examined the snowpack under canopies of a spruce forest in the central Rocky Mountains, USA, using the SnowMicroPen (SMP), a high resolution digital penetrometer. Weekly-repeated penetration force measurements were recorded along 10 m transects every 0.3 m in winter 2015 and bi-weekly along 20 m transects every 0.5 m in 2016 in three study plots beneath canopies of undisturbed, bark beetle-disturbed and harvested forest stands, and an open meadow. To disentangle information about layer hardness and depth variabilities, and to quantitatively compare the different SMP profiles, we applied a matching algorithm to our dataset, which combines several profiles by automatically adjusting their layer thicknesses. We linked spatial and temporal variabilities of penetration force and depth, and thus snow stratigraphy to forest and meteorological conditions. Throughout the season, snow stratigraphy was more heterogeneous in undisturbed but also beneath bark beetle-disturbed forests. In contrast, and despite remaining small diameter trees and woody debris, snow stratigraphy was rather homogenous at the harvested plot. As expected, layering at the non-forested plot varied only slightly over the small spatial extent sampled. At the open and harvested plots, persistent crusts and ice lenses were clearly present in the snowpack, while such hard layers barely occurred beneath undisturbed and disturbed canopies. Due to settling, hardness significantly increased with depth at

  16. Simulation of the shallow groundwater-flow system in the Forest County Potawatomi Community, Forest County, Wisconsin

    Science.gov (United States)

    Fienen, Michael N.; Saad, David A.; Juckem, Paul F.

    2013-01-01

    The shallow groundwater system in the Forest County Potawatomi Comminity, Forest County, Wisconsin, was simulated by expanding and recalibrating a previously calibrated regional model. The existing model was updated using newly collected water-level measurements, inclusion of surface-water features beyond the previous near-field boundary, and refinements to surface-water features. The updated model then was used to calculate the area contributing recharge for seven existing and three proposed pumping locations on lands of the Forest County Potawatomi Community. The existing wells were the subject of a 2004 source-water evaluation in which areas contributing recharge were calculated using the fixed-radius method. The motivation for the present (2012) project was to improve the level of detail of areas contributing recharge for the existing wells and to provide similar analysis for the proposed wells. Delineated 5- and 10-year areas contributing recharge for existing and proposed wells extend from the areas of pumping to delineate the area at the surface contributing recharge to the wells. Steady-state pumping was simulated for two scenarios: a base-pumping scenario using pumping rates that reflect what the Community currently (2012) pumps (or plans to in the case of proposed wells), and a high-pumping scenario in which the rate was set to the maximum expected from wells installed in this area, according to the Forest County Potawatomi Community Natural Resources Department. In general, the 10-year areas contributing recharge did not intersect surface-water bodies. The 5- and 10-year areas contributing recharge simulated at the maximum pumping rate at Bug Lake Road may intersect Bug Lake. At the casino near the Town of Carter, Wisconsin, the 10-year areas contributing recharge intersect infiltration ponds. At the Devils Lake and Lois Crow Drive wells, areas contributing recharge are near cultural features, including residences.

  17. Partners in flight bird conservation plan for the Upper Great Lakes Plain (Physiographic Area 16)

    Science.gov (United States)

    Knutson, M.G.; Butcher, G.; Fitzgerald, J.; Shieldcastle, J.

    2001-01-01

    1 November 2001. Conservation of bird habitats is a major focus of effort by Partners in Flight, an international coalition of agencies, citizens, and other groups dedicated to 'keeping common birds common'. USGS worked on a planning team to publish a bird conservation plan for the Upper Great Lakes Plain ecoregion (PIF 16), which includes large portions of southern Wisconsin, southern Michigan and parts of Minnesota, Iowa, Illinois, Indiana, and Ohio. The conservation plan outlines specific habitat restoration and bird population objectives for the ecoregion over the next decade. The plan provides a context for on-the-ground conservation implementation by the US Fish and Wildlife Service, the USDA Natural Resources Conservation Service, the US Forest Service, states, and conservation groups. Citation: Knutson, M. G., G. Butcher, J. Fitzgerald, and J. Shieldcastle. 2001. Partners in Flight Bird Conservation Plan for The Upper Great Lakes Plain (Physiographic Area 16). USGS Upper Midwest Environmental Sciences Center in cooperation with Partners in Flight, La Crosse, Wisconsin. Download from website: http://www.blm.gov/wildlife/pifplans.htm. The Upper Great Lakes Plain covers the southern half of Michigan, northwest Ohio, northern Indiana, northern Illinois, southern Wisconsin, and small portions of southwest Minnesota and northwest Iowa. Glacial moraines and dissected plateaus are characteristic of the topography. Broadleaf forests, oak savannahs, and a variety of prairie communities are the natural vegetation types. A oDriftless Areao was not glaciated during the late Pleistocene and emerged as a unique area of great biological diversity. Priority bird species for the area include the Henslow's Sparrow, Sedge Wren, Bobolink, Golden-winged Warbler, Cerulean Warbler, Black-billed Cuckoo, and Red-headed Woodpecker. There are many large urban centers in this area whose growth and sprawl will continue to consume land. The vast majority of the presettlement forest and

  18. Visual observations of historical lake trout spawning grounds in western Lake Huron

    Science.gov (United States)

    Nester, Robert T.; Poe, Thomas P.

    1987-01-01

    Direct underwater video observations were made of the bottom substrates at 12 spawning grounds formerly used by lake trout Salvelinus namaycush in western Lake Huron to evaluate their present suitability for successful reproduction by lake trout. Nine locations examined north of Saginaw Bay in the northwestern end of the lake are thought to provide the best spawning habitat. The substrate at these sites consisted of angular rough cobble and rubble with relatively deep interstitial spaces (a?Y 0.5 m), small amounts of fine sediments, and little or no periphytic growth. Conditions at the three other sampling locations south of Saginaw Bay seemed much less suitable for successful reproduction based on the reduced area of high-quality substrate, shallow interstitial spaces, high infiltration of fine sediments, and greater periphytic growth.

  19. Use of the flooded forest by fish assemblages in lakes of the National Park of Anavilhanas (Amazonas, Brazil Uso do igapó por assembléias de peixes nos lagos no Parque Nacional das Anavilhanas (Amazonas, Brasil

    Directory of Open Access Journals (Sweden)

    Janette Noveras

    2012-01-01

    Full Text Available We evaluated diversity and distribution of fish species in two habitats: flooded forest and open water of lakes of Rio Negro. Each of four lakes within the Anavilhanas Archipelago was sampled three times from 2009-2010. Species diversity generally was higher in flooded forests and at night, according to correspondence analysis. Predators were most active at night, but showed no preference between the flooded forest and open water habitats. Omnivores, filter feeders, and detritivores were most active during the day.Avaliamos a diversidade e a distribuição de espécies de peixes em dois habitats: floresta alagada e água aberta de lagos do rio Negro. Três amostragens foram realizadas em quatro lagos do Arquipélago de Anavilhanas, em 2009 e 2010. Em geral, a diversidade de espécies foi maior na floresta alagada e durante a noite. A análise de correspondência indicou que predadores estavam mais ativos a noite nos dois habitats. Onívoros, filtradores e detritívoros foram mais capturados durante o dia.

  20. Lake variability: Key factors controlling mercury concentrations in New York State fish

    International Nuclear Information System (INIS)

    Simonin, Howard A.; Loukmas, Jefferey J.; Skinner, Lawrence C.; Roy, Karen M.

    2008-01-01

    A 4 year study surveyed 131 lakes across New York State beginning in 2003 to improve our understanding of mercury and gather information from previously untested waters. Our study focused on largemouth and smallmouth bass, walleye and yellow perch, common piscivorous fish shown to accumulate high mercury concentrations and species important to local fisheries. Fish from Adirondack and Catskill Forest Preserve lakes generally had higher mercury concentrations than those from lakes in other areas of the state. Variability between nearby individual lakes was observed, and could be due to differences in water chemistry, lake productivity or the abundance of wetlands in the watershed. We found the following factors impact mercury bioaccumulation: fish length, lake pH, specific conductivity, chlorophyll a, mercury concentration in the water, presence of an outlet dam and amount of contiguous wetlands. - Lake water chemistry variables, dams, and wetlands play major roles in determining fish mercury concentrations

  1. Prediction of small hydropower plant power production in Himreen Lake dam (HLD using artificial neural network

    Directory of Open Access Journals (Sweden)

    Ali Thaeer Hammid

    2018-03-01

    Full Text Available In developing countries, the power production is properly less than the request of power or load, and sustaining a system stability of power production is a trouble quietly. Sometimes, there is a necessary development to the correct quantity of load demand to retain a system of power production steadily. Thus, Small Hydropower Plant (SHP includes a Kaplan turbine was verified to explore its applicability. This paper concentrates on applying on Artificial Neural Networks (ANNs by approaching of Feed-Forward, Back-Propagation to make performance predictions of the hydropower plant at the Himreen lake dam-Diyala in terms of net turbine head, flow rate of water and power production that data gathered during a research over a 10 year period. The model studies the uncertainties of inputs and output operation and there's a designing to network structure and then trained by means of the entire of 3570 experimental and observed data. Furthermore, ANN offers an analyzing and diagnosing instrument effectively to model performance of the nonlinear plant. The study suggests that the ANN may predict the performance of the plant with a correlation coefficient (R between the variables of predicted and observed output that would be higher than 0.96. Keywords: Himreen Lake Dam, Small Hydropower plants, Artificial Neural Networks, Feed forward-back propagation model, Generation system's prediction

  2. Differential response of vegetation in Hulun Lake region at the northern margin of Asian summer monsoon to extreme cold events of the last deglaciation

    Science.gov (United States)

    Zhang, Shengrui; Xiao, Jule; Xu, Qinghai; Wen, Ruilin; Fan, Jiawei; Huang, Yun; Yamagata, Hideki

    2018-06-01

    The response of vegetation to extreme cold events during the last deglaciation is important for assessing the impact of possible extreme climatic events on terrestrial ecosystems under future global warming scenarios. Here, we present a detailed record of the development of regional vegetation in the northern margin of Asian summer monsoon during the last deglaciation (16,500-11,000 cal yr BP) based on a radiocarbon-dated high-resolution pollen record from Hulun Lake, northeast China. The results show that the regional vegetation changed from subalpine meadow-desert steppe to mixed coniferous and deciduous forest-typical steppe during the last deglaciation. However, its responses to the Heinrich event 1 (H1) and the Younger Dryas event (YD) were significantly different: during the H1 event, scattered sparse forest was present in the surrounding mountains, while within the lake catchment the vegetation cover was poor and was dominated by desert steppe. In contrast, during the YD event, deciduous forest developed and the proportion of coniferous forest increased in the mountains, the lake catchment was occupied by typical steppe. We suggest that changes in Northern Hemisphere summer insolation and land surface conditions (ice sheets and sea level) caused temperature and monsoonal precipitation variations that contributed to the contrasting vegetation response during the two cold events. We conclude that under future global warming scenarios, extreme climatic events may cause a deterioration of the ecological environment of the Hulun Lake region, resulting in increased coniferous forest and decreased total forest cover in the surrounding mountains, and a reduction in typical steppe in the lake catchment.

  3. Hydro-climatic forcing of dissolved organic carbon in two boreal lakes of Canada.

    Science.gov (United States)

    Diodato, Nazzareno; Higgins, Scott; Bellocchi, Gianni; Fiorillo, Francesco; Romano, Nunzio; Guadagno, Francesco M

    2016-11-15

    The boreal forest of the northern hemisphere represents one of the world's largest ecozones and contains nearly one third of the world's intact forests and terrestrially stored carbon. Long-term variations in temperature and precipitation have been implied in altering carbon cycling in forest soils, including increased fluxes to receiving waters. In this study, we use a simple hydrologic model and a 40-year dataset (1971-2010) of dissolved organic carbon (DOC) from two pristine boreal lakes (ELA, Canada) to examine the interactions between precipitation and landscape-scale controls of DOC production and export from forest catchments to surface waters. Our results indicate that a simplified hydrologically-based conceptual model can enable the long-term temporal patterns of DOC fluxes to be captured within boreal landscapes. Reconstructed DOC exports from forested catchments in the period 1901-2012 follow largely a sinusoidal pattern, with a period of about 37years and are tightly linked to multi-decadal patterns of precipitation. By combining our model with long-term precipitation estimates, we found no evidence of increasing DOC transport or in-lake concentrations through the 20th century. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Local fish extinction in a small tropical lake in Brazil

    Directory of Open Access Journals (Sweden)

    Paulo dos Santos Pompeu

    Full Text Available Lagoa Santa is a shallow permanent lake, located in Belo Horizonte metropolitan region, Brazil. In this study, the loss in fish diversity of the lake over the past 150 years is evaluated. Local extinction of almost 70% of the original fish fauna is described. Probably, the main causes of this richness loss were: obstruction of natural communication with rio das Velhas, non-native species introduction, change in the water level, organic pollution, and elimination of littoral and submerged vegetation.

  5. Appraisal of Farm Forestry Department around Tinderet Forest

    International Nuclear Information System (INIS)

    Nyambati, R.O; Koech, C.K; Muok, G

    2007-01-01

    Tinderet forest is one of the most important catchment areas of lake victoria. It is the main source of numerous springs, streams, and rivers that flow into the lake. The forest is also an important habitat for wide variety of water plants and animal species. Although the forest is gazetted as a forest reserve, it has undergone different levels of degradation due to over exploitation of timber, posts, firewood, charcoal and honey by the community living next to the forest. Resource from the forest supplement the communities' meagre income from subsistence farming. A survey was conducted in four Divisions (Chichila, Kipkelion, Fort-Tanan and Tinderet) around the forest to evaluate the status of farm forestry development and underlying reasons for encroachment in the forest. The results showed that, 61% of the people around Tinderet forest were settlers, whose duration of settlement is between 30-40 years. Most farmers were involved in various forms of farming (livestock or crop production) but forestry was not reported as a major activity. Clearing for livestock and crop production, timber for construction and firewood are the main causes of vegetation depletion on farms. Upto 60% of the households were not self reliant on wood products mainly timber and firewood and Fort-Tana (78%) and Kipkelion (70%) were the most affected. Forestry extension services were mainly provided by the Ministry of Agriculture and East African Wildlife Society (EAWS) and were found to be poor on the ground. Other issues that hampered forest development are inadequate provision of germplasm (seed and seedlings). There is therefore a need to build the capacity of the community in the farm forestry through establishment of nurseries and provision of adequate extension services. This would contribute to enhancement of self-reliance in wood products and increased income reducing encroachment into the gazetted forest

  6. An assessment of forest landowner interest in selling forest carbon credits in the Lake States, USA

    Science.gov (United States)

    Kristell A. Miller; Stephanie A. Snyder; Michael A. Kilgore

    2012-01-01

    The nation's family forest lands can be an important contributor to carbon sequestration efforts. Yet very little is known about how family forest landowners view programs that enable them to sell carbon credits generated from the growth of their forest and the compensation that would be required to encourage a meaningful level of participation. To address this...

  7. Toxicological evaluation of a lake ecosystem contaminated with crude oil

    International Nuclear Information System (INIS)

    Twigg, D.; Ramey, B.

    1995-01-01

    Winona Lake on the Daniel Boone National Forest in Powell County, Kentucky, was used from the mid 1950's to 1987 as a water source for water-injection oil drilling and as a brine disposal site. The lake was contaminated with excessive amounts of crude oil. A multi phase investigation was conducted, including chemical analysis of water and sediment, water toxicity tests using a cladoceran, Ceriodaphnia dubia, sediment toxicity tests using an amphipod, Hyalella azteca, and a faunal survey of the communities of the lake and stream both above and below the lake. The sediment was laden with petroleum hydrocarbons (4.1 parts per thousand), while the water showed no contamination. The C dubia test results showed no significant water toxicity. The contaminated sediment adjacent to the dam produced 75% mortality in H. azteca. The faunal survey indicated little or no impact on the upstream and downstream communities but the lake community was highly impacted, especially the benthos. Pollution tolerant Chaoborus sp. were the only organisms collected from sediment samples dredged from the lake. Contamination was limited to the sediment within the lake but the impact on the entire lake community was severe

  8. Promoting biodiversity values of small forest patches in agricultural landscapes: Ecological drivers and social demand.

    Science.gov (United States)

    Varela, Elsa; Verheyen, Kris; Valdés, Alicia; Soliño, Mario; Jacobsen, Jette B; De Smedt, Pallieter; Ehrmann, Steffen; Gärtner, Stefanie; Górriz, Elena; Decocq, Guillaume

    2018-04-01

    Small forest patches embedded in agricultural (and peri-urban) landscapes in Western Europe play a key role for biodiversity conservation with a recognized capacity of delivering a wide suite of ecosystem services. Measures aimed to preserve these patches should be both socially desirable and ecologically effective. This study presents a joint ecologic and economic assessment conducted on small forest patches in Flanders (Belgium) and Picardie (N France). In each study region, two contrasted types of agricultural landscapes were selected. Open field (OF) and Bocage (B) landscapes are distinguished by the intensity of their usage and higher connectivity in the B landscapes. The social demand for enhancing biodiversity and forest structure diversity as well as for increasing the forest area at the expenses of agricultural land is estimated through an economic valuation survey. These results are compared with the outcomes of an ecological survey where the influence of structural features of the forest patches on the associated herbaceous diversity is assessed. The ecological and economic surveys show contrasting results; increasing tree species richness is ecologically more important for herbaceous diversity in the patch, but both tree species richness and herbaceous diversity obtain insignificant willingness to pay estimates. Furthermore, although respondents prefer the proposed changes to take place in the region where they live, we find out that social preferences and ecological effectiveness do differ between landscapes that represent different intensities of land use. Dwellers where the landscape is perceived as more "degraded" attach more value to diversity enhancement, suggesting a prioritization of initiatives in these area. In contrast, the ecological analyses show that prioritizing the protection and enhancement of the relatively better-off areas is more ecologically effective. Our study calls for a balance between ecological effectiveness and welfare

  9. Yellowstone Lake Nanoarchaeota

    Directory of Open Access Journals (Sweden)

    Scott eClingenpeel

    2013-09-01

    Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  10. Late Pleistocene to Holocene lake levels of Lake Warner, Oregon (USA) and their effect on archaeological site distribution patterns

    Science.gov (United States)

    Wriston, T.; Smith, G. M.

    2017-12-01

    Few chronological controls are available for the rise and fall of small pluvial lake systems in the Northwestern Great Basin. Within Warner Basin this control was necessary for interpretation of known archaeological sites and for predicting where evidence of its earliest inhabitants might be expected. We trenched along relic beach ridges of Lake Warner, surveyed a stratified sample of the area for archaeological sites, and excavated some sites and a nearby rockshelter. These efforts produced new ages that we used to construct a lake level curve for Lake Warner. We found that the lake filled the valley floor between ca. 30,000 cal yr BP and ca. 10,300 cal yr BP. In nearby basins, several oscillations are evident before ca. 21,100 cal yr BP, but a steep rise to the LGM maximum occurred between 21,000 and 20,000 cal yr BP. Lake Warner likely mirrored these changes, dropped to the valley floor ca. 18,340 cal yr BP, and then rose to its maximum highstand when its waters briefly reached 1454 m asl. After this highstand the lake receded to moderately high levels. Following ca. 14,385 cal yr BP, the lake oscillated between moderate to moderately-high levels through the Bolling-Allerod interstadials and into the Younger Dryas stadial. The basin's first occupants arrived along its shore around this time, while the lake still filled the valley floor. These earliest people carried either Western Stemmed or Clovis projectile points, both of which are found along the lake margin. The lake receded into the valley floor ca. 10,300 cal yr BP and dune development began, ringing wetlands and small lakes that persisted in the footprint of the once large lake. By the time Mazama tephra fell 7,600 cal yr BP it blanketed pre-existing dunes and marsh peats. Our Lake Warner lake level curve facilitates interdisciplinary testing and refinement of it and similar curves throughout the region while helping us understand the history of lake and the people who lived along its shores.

  11. Are all temperate lakes eutrophying in a warmer world?

    Science.gov (United States)

    Paltsev, A.; Creed, I. F.

    2017-12-01

    Freshwater lakes are at risk of eutrophication due to climate change and intensification of human activities on the planet. In relatively undisturbed areas of the temperate forest biome, lakes are "sentinels" of the effects of rising temperatures. We hypothesise that rising temperatures are driving a shift from nutrient-poor oligotrophic states to nutrient-rich eutrophic states. To test this hypothesis, we examined a time series of satellite based chlorophyll-a (a proxy of algal biomass) of 12,000+ lakes over 30 years in the Canadian portion of the Laurentian Great Lakes basin. From the time series, non-stationary trends (detected by Mann-Kendall analysis) and stationary cycles (revealed through Morlet wavelet analysis) were removed, and the standard deviation (SD) of the remaining residuals was used as an indicator of lake stability. Four classes of lake stability were identified: (1) stable (SD is consistently low); (2) destabilizing (SD increases over time); (3) unstable (SD is consistently high); and (4) stabilizing lakes (SD decreases over time). Stable lakes were either oligotrophic or eutrophic indicating the presence of two stable states in the region. Destabilizing lakes were shifting from oligotrophic to lakes with a higher trophic status (indicating eutrophication), unstable lakes were mostly mesotrophic, and stabilizing lakes were shifting from eutrophic to the lakes with lower trophic status (indicating oligotrophication). In contrast to common expectations, while many lakes (2142) were shifting from oligotrophic to eutrophic states, more lakes (3199) were showing the opposite trend and shifting from eutrophic to oligotrophic states. This finding reveals a complexity of lake responses to rising temperatures and the need to improve understanding of why some lakes shift while others do not. Future work is focused on exploring the interactive effects of global, regional, and local drivers of lake trophic states.

  12. Adjusting the Stems Regional Forest Growth Model to Improve Local Predictions

    Science.gov (United States)

    W. Brad Smith

    1983-01-01

    A simple procedure using double sampling is described for adjusting growth in the STEMS regional forest growth model to compensate for subregional variations. Predictive accuracy of the STEMS model (a distance-independent, individual tree growth model for Lake States forests) was improved by using this procedure

  13. The regional abundance and size distribution of lakes and reservoirs in the United States and implication for estimates of global lake extent

    Science.gov (United States)

    McDonald, Cory P.; Rover, Jennifer; Stets, Edward G.; Striegl, Robert G.

    2012-01-01

    We analyzed complete geospatial data for the 3.5 million lakes and reservoirs larger than 0.001 km2, with a combined surface area of 131,000 km2, in the contiguous United States (excluding the Laurentian Great Lakes) and identified their regional distribution characteristics. For Alaska, we also analyzed (1) incomplete data that suggest that the state contains 1–2.5 million lakes larger than 0.001 km2 covering over 50,000 km2 and (2) localized high-resolution (5 m) data that suggest that the number of very small water bodies ( 0.001 km2 in some areas. The Pareto distribution cannot accurately describe the lake abundance-size relationship across the entire size spectrum, and extrapolation of this density function to small size classes has likely resulted in the overestimation of the number of small lakes in the world. While small water bodies dominate in terms of numbers, they are not numerous enough to dominate in terms of surface area, as has been previously suggested. Extending our results to the global scale suggests that there are on the order of 64 million water bodies larger than 0.001 km2 in the world, with a total surface area of approximately 3.8 million km2.

  14. Hydrologic-energy balance constraints on the Holocene lake-level history of lake Titicaca, South America

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, H.D.; Dunbar, R.B. [Stanford University, Geological and Environmental Sciences, Stanford, CA (United States)

    2004-09-01

    A basin-scale hydrologic-energy balance model that integrates modern climatological, hydrological, and hypsographic observations was developed for the modern Lake Titicaca watershed (northern Altiplano, South America) and operated under variable conditions to understand controls on post-glacial changes in lake level. The model simulates changes in five environmental variables (air temperature, cloud fraction, precipitation, relative humidity, and land surface albedo). Relatively small changes in three meteorological variables (mean annual precipitation, temperature, and/or cloud fraction) explain the large mid-Holocene lake-level decrease ({proportional_to}85 m) inferred from seismic reflection profiling and supported by sediment-based paleoproxies from lake sediments. Climatic controls that shape the present-day Altiplano and the sediment-based record of Holocene lake-level change are combined to interpret model-derived lake-level simulations in terms of changes in the mean state of ENSO and its impact on moisture transport to the Altiplano. (orig.)

  15. Hydrologic-energy balance constraints on the Holocene lake-level history of lake Titicaca, South America

    Science.gov (United States)

    Rowe, H. D.; Dunbar, R. B.

    2004-09-01

    A basin-scale hydrologic-energy balance model that integrates modern climatological, hydrological, and hypsographic observations was developed for the modern Lake Titicaca watershed (northern Altiplano, South America) and operated under variable conditions to understand controls on post-glacial changes in lake level. The model simulates changes in five environmental variables (air temperature, cloud fraction, precipitation, relative humidity, and land surface albedo). Relatively small changes in three meteorological variables (mean annual precipitation, temperature, and/or cloud fraction) explain the large mid-Holocene lake-level decrease (˜85 m) inferred from seismic reflection profiling and supported by sediment-based paleoproxies from lake sediments. Climatic controls that shape the present-day Altiplano and the sediment-based record of Holocene lake-level change are combined to interpret model-derived lake-level simulations in terms of changes in the mean state of ENSO and its impact on moisture transport to the Altiplano.

  16. Strong evidence for terrestrial support of zooplankton in small lakes based on stable isotopes of carbon, nitrogen, and hydrogen

    Science.gov (United States)

    Cole, J.J.; Carpenter, S.R.; Kitchell, J.; Pace, M.L.; Solomon, C.T.; Weidel, B.

    2011-01-01

    Cross-ecosystem subsidies to food webs can alter metabolic balances in the receiving (subsidized) system and free the food web, or particular consumers, from the energetic constraints of local primary production. Although cross-ecosystem subsidies between terrestrial and aquatic systems have been well recognized for benthic organisms in streams, rivers, and the littoral zones of lakes, terrestrial subsidies to pelagic consumers are more difficult to demonstrate and remain controversial. Here, we adopt a unique approach by using stable isotopes of H, C, and N to estimate terrestrial support to zooplankton in two contrasting lakes. Zooplankton (Holopedium, Daphnia, and Leptodiaptomus) are comprised of ???20-40% of organic material of terrestrial origin. These estimates are as high as, or higher than, prior measures obtained by experimentally manipulating the inorganic 13C content of these lakes to augment the small, natural contrast in 13C between terrestrial and algal photosynthesis. Our study gives credence to a growing literature, which we review here, suggesting that significant terrestrial support of pelagic crustaceans (zooplankton) is widespread.

  17. Lake acidification in the Adirondack Mountains of New York causes and consequences

    Science.gov (United States)

    Carl L. Schofield

    1976-01-01

    Current and historic geographic distributions of acidity in Adirondack lakes were examined in relation to regional edaphic, climatic, and physiographic features. Acid conditions are currently predominant in high elevation drainage lakes having small watershed/surface area ratios. Comparable levels of acidity were found only in small seepage lakes and bog ponds during...

  18. Sources and distribution of microplastics in China's largest inland lake - Qinghai Lake.

    Science.gov (United States)

    Xiong, Xiong; Zhang, Kai; Chen, Xianchuan; Shi, Huahong; Luo, Ze; Wu, Chenxi

    2018-04-01

    Microplastic pollution was studied in China's largest inland lake - Qinghai Lake in this work. Microplastics were detected with abundance varies from 0.05 × 10 5 to 7.58 × 10 5 items km -2 in the lake surface water, 0.03 × 10 5 to 0.31 × 10 5 items km -2 in the inflowing rivers, 50 to 1292 items m -2 in the lakeshore sediment, and 2 to 15 items per individual in the fish samples, respectively. Small microplastics (0.1-0.5 mm) dominated in the lake surface water while large microplastics (1-5 mm) are more abundant in the river samples. Microplastics were predominantly in sheet and fiber shapes in the lake and river water samples but were more diverse in the lakeshore sediment samples. Polymer types of microplastics were mainly polyethylene (PE) and polypropylene (PP) as identified using Raman Spectroscopy. Spatially, microplastic abundance was the highest in the central part of the lake, likely due to the transport of lake current. Based on the higher abundance of microplastics near the tourist access points, plastic wastes from tourism are considered as an important source of microplastics in Qinghai Lake. As an important area for wildlife conservation, better waste management practice should be implemented, and waste disposal and recycling infrastructures should be improved for the protection of Qinghai Lake. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Ice formation in subglacial Lake Vostok, Central Antarctica

    Science.gov (United States)

    Souchez, R.; Petit, J. R.; Tison, J.-L.; Jouzel, J.; Verbeke, V.

    2000-09-01

    The investigation of chemical and isotopic properties in the lake ice from the Vostok ice core gives clues to the mechanisms involved in ice formation within the lake. A small lake water salinity can be reasonably deduced from the chemical data. Possible implications for the water circulation of Lake Vostok are developed. The characteristics of the isotopic composition of the lake ice indicate that ice formation in Lake Vostok occurred by frazil ice crystal generation due to supercooling as a consequence of rising waters and a possible contrast in water salinity. Subsequent consolidation of the developed loose ice crystals results in the accretion of ice to the ceiling of the lake.

  20. Use of Natural 35S to Trace Sulphate Cycling in Small Lakes, Flattops Wilderness Area, Colorado, U.S.A

    International Nuclear Information System (INIS)

    Michel, Robert L.; Turk, John T.; Campbell, Donald H.; Mast, M. A.

    2002-01-01

    Measurements of the cosmogenically-produced 35 S, a radioisotope of sulphur (t 1/2 = 87 days), are reported for the Ned Wilson Lake watershed in Colorado. The watershed contains two small lakes and a flowing spring presumed to be representative of local ground water. The watershed is located in the Flattops Wilderness Area and the waters in the system have low alkalinity, making them sensitive to increases in acid and sulphate deposition. Time series of 35 S measurements were made during the summers of 1995 and 1996 (July-September) at all three sites. The system is dominated by melting snow and an initial concentration of 16-20 mBq L -1 was estimated for snow melt based on a series of snow samples collected in the Rocky Mountains. The two lakes had large initial 35 S concentrations in July, indicating that a large fraction of the lake water and sulphate was introduced by meltwater from that year's snowpack. In 1995 and 1996, 35 S concentrations decreased more rapidly than could be accounted for by decay, indicating that other processes were affecting 35 S concentrations. The most likely explanation is that exchange with sediments or the biota was removing 35 S from the lake and replacing it with older sulphate devoid of 35 S. In September of 1995 and 1996, 35 S concentrations increased, suggesting that atmospheric deposition is important in the sulphate flux of these lakes in late summer. Sulphur-35 concentrations in the spring water were highly variable but never higher than 3.6 mBq L -1 and averaged 2 mBq L -1 . Using a simple mixing model, it was estimated that 75% of the spring water was derived from precipitation of previous years

  1. Use of natural 35S to trace sulphate cycling in small lakes, Flattops Wilderness Area, Colorado, U.S.A.

    Science.gov (United States)

    Michel, Robert L.; Turk, John T.; Campbell, Donald H.; Mast, M. Alisa

    2002-01-01

    Measurements of the cosmogenically-produced 35S, a radioisotope of sulphur (t1/2 = 87 days), are reported for the Ned Wilson Lake watershed in Colorado. The watershed contains two small lakes and a flowing spring presumed to be representative of local ground water. The watershed is located in the Flattops Wilderness Area and the waters in the system have low alkalinity, making them sensitive to increases in acid and sulphate deposition. Time series of 35S measurements were made during the summers of 1995 and 1996 (July–September) at all three sites. The system is dominated by melting snow and an initial concentration of 16–20 mBq L-1was estimated for snowmelt based on a series of snow samples collected in the Rocky Mountains. The two lakes had large initial 35S concentrations in July, indicating that a large fraction of the lake water and sulphate was introduced by meltwater from that year's snowpack. In 1995 and 1996, 35S concentrations decreased more rapidly than could be accounted for by decay, indicating that other processes were affecting 35S concentrations. The most likely explanation is that exchange with sediments or the biota was removing 35S from the lake and replacing it with older sulphate devoid of 35S. In September of 1995 and 1996, 35S concentrations increased, suggesting that atmospheric deposition is important in the sulphate flux of these lakes in late summer. Sulphur-35 concentrations in the spring water were highly variable but never higher than 3.6 mBq L-1 and averaged 2 mBq L-1. Using a simple mixing model, it was estimated that 75% of the spring water was derived from precipitation of previous years.

  2. Impacts of Tropical Forest Disturbance Upon Avifauna on a Small Island with High Endemism: Implications for Conservation

    Directory of Open Access Journals (Sweden)

    Martin Thomas

    2010-01-01

    Full Text Available Tropical forests are rapidly being lost across Southeast Asia and this is predicted to have severe implications for many of the region′s bird species. However, relationships between forest disturbance and avifaunal assemblages remain poorly understood, particularly on small island ecosystems such as those found in the biodiversity ′hotspot′ of Wallacea. This study examines how avifaunal richness varies across a disturbance gradient in a forest reserve on Buton Island, southeast Sulawesi. Particular emphasis is placed upon examining responses in endemic and red-listed species with high conservation importance. Results indicate that overall avian richness increases between primary and 30-year-old regenerating secondary forest and then decreases through disturbed secondary forest, but is highest in cleared farmland. However, high species richness in farmland does not signify high species distinctiveness; bird community composition here differs significantly from that found in forest sites, and is poor in supporting forest specialists and endemic species. Certain large-bodied endemics such as the Knobbed Hornbill (Rhyticeros cassidix appear to be sensitive to moderate disturbance, with populations occurring at greatest density within primary forest. However, overall endemic species richness, as well as that of endemic frugivores and insectivores, is similar in primary and secondary forest types. Results indicate that well-established secondary forest in particular has an important role in supporting species with high conservational importance, possessing community composition similar to that found in primary forest and supporting an equally high richness of endemic species.

  3. Bet-hedging dry-forest resilience to climate-change threats in the western USA based on historical forest structure

    Directory of Open Access Journals (Sweden)

    William Lawrence Baker

    2015-01-01

    Full Text Available Dry forests are particularly subject to wildfires, insect outbreaks, and droughts that likely will increase with climate change. Efforts to increase resilience of dry forests often focus on removing most small trees to reduce wildfire risk. However, small trees often survive other disturbances and could provide broader forest resilience, but small trees are thought to have been historically rare. We used direct records by land surveyors in the late-1800s along 22,206 km of survey lines in 1.7 million ha of dry forests in the western USA to test this idea. These systematic surveys (45,171 trees of historical forests reveal that small trees dominated (52-92% of total trees dry forests. Historical forests also included diverse tree sizes and species, which together provided resilience to several types of disturbances. Current risk to dry forests from insect outbreaks is 5.6 times the risk of higher-severity wildfires, with small trees increasing forest resilience to insect outbreaks. Removal of most small trees to reduce wildfire risk may compromise the bet-hedging resilience, provided by small trees and diverse tree sizes and species, against a broad array of unpredictable future disturbances.

  4. Fishing for compliments : man-made lake exceeds expectations

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, L.

    2010-10-15

    This article discussed the unexpected benefits of the first man-made lake created to compensate for loss of habitat resulting from the construction of an oilsands mine. Wapan Sakahikan Lake appears to be diverting birds from a tailings pond in the vicinity, and more fish species than expected are showing up in the lake. Canadian Natural Resources Limited diverted and dammed the Tar River to make way for an oilsands mine. About 30 people were involved in the design and construction of the lake, which encompasses 80 hectares and is 19 feet deep, with shallower areas to facilitate spawning and the maturation of juvenile fish. Small islands, gravel beds, and an underwater trench for small fish to take shelter were also constructed. Special culverts help keep fish in the lake. A metre-deep layer of clay lines the lake to help prevent mercury contamination. With the aid of the spring melt, it took only three days to fill the lake. Nearby First Nations were consulted regarding the location and fish species to stock. Other oilsands companies are now creating compensation lakes, and what was learned in the creation of Wapan Sakahikan will be shared via the Regional Aquatic Monitoring Program. 1 ref., 1 fig.

  5. Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes

    Science.gov (United States)

    Miyazono, S.; Aycock, J.N.; Miranda, L.E.; Tietjen, T.E.

    2010-01-01

    We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species-environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes. ?? 2010 John Wiley & Sons A/S.

  6. Recreational Exposure to Low Concentrations of Microcystins During an Algal Bloom in a Small Lake

    Directory of Open Access Journals (Sweden)

    Yung-Sung Cheng

    2008-06-01

    Full Text Available We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-μg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses, but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 μg/L to 5 μg/L in the water and (<0.1 ng/m3 in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147μg/L. Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins.

  7. Spatial characterization of acid rain stress in Canadian Shield Lakes

    Science.gov (United States)

    Tanis, Fred J.

    1987-01-01

    The acidification of lake waters from airborne pollution is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern U.S. and on the Canadian Shield is though to be enormous. How seasonal changes in lake transparency are related to annual acidic load was examined. The relationship between variations in lake acidification and ecophysical units was also examined. The utility of Thematic Mapper based observations to measure seasonal changes in the optical transparency in acid lakes was investigated. The potential for this optical response is related to a number of local ecophysical factors with bedrock geology being, perhaps, the most important. Other factors include sulfate deposition, vegetative cover, and terrain drainage/relief. The area of southern Ontario contains a wide variety of geologies from the most acid rain sensitive granite quartzite types to the least sensitive limestone dolomite sediments. Annual sulfate deposition ranges from 1.0 to 4.0 grams/sq m.

  8. Estimating Spring Condensation on the Great Lakes

    Science.gov (United States)

    Meyer, A.; Welp, L.

    2017-12-01

    The Laurentian Great Lakes region provides opportunities for shipping, recreation, and consumptive water use to a large part of the United States and Canada. Water levels in the lakes fluctuate yearly, but attempts to model the system are inadequate because the water and energy budgets are still not fully understood. For example, water levels in the Great Lakes experienced a 15-year low period ending in 2013, the recovery of which has been attributed partially to decreased evaporation and increased precipitation and runoff. Unlike precipitation, the exchange of water vapor between the lake and the atmosphere through evaporation or condensation is difficult to measure directly. However, estimates have been constructed using off-shore eddy covariance direct measurements of latent heat fluxes, remote sensing observations, and a small network of monitoring buoys. When the lake surface temperature is colder than air temperature as it is in spring, condensation is larger than evaporation. This is a relatively small component of the net annual water budget of the lakes, but the total amount of condensation may be important for seasonal energy fluxes and atmospheric deposition of pollutants and nutrients to the lakes. Seasonal energy fluxes determine, and are influenced by, ice cover, water and air temperatures, and evaporation in the Great Lakes. We aim to quantify the amount of spring condensation on the Great Lakes using the National Center for Atmospheric Prediction North American Regional Reanalysis (NCEP NARR) Data for Winter 2013 to Spring 2017 and compare the condensation values of spring seasons following high volume, high duration and low volume, low duration ice cover.

  9. Small-area estimation of forest attributes within fire boundaries

    Science.gov (United States)

    T. Frescino; G. Moisen; K. Adachi; J. Breidt

    2014-01-01

    Wildfires are gaining more attention every year as they burn more frequently, more intensely, and across larger landscapes. Generating timely estimates of forest resources within fire perimeters is important for land managers to quickly determine the impact of fi res on U.S. forests. The U.S. Forest Service’s Forest Inventory and Analysis (FIA) program needs tools to...

  10. Selecting Tree Species with High Carbon Stock Potency from Tropical Upland Forest of Bedugul-Bali, Indonesia

    Directory of Open Access Journals (Sweden)

    Arief Priyadi

    2014-11-01

    Full Text Available Vegetation studies to reveal tree diversity and its contribution to carbon stock were conducted in three different sites of upland forest in Bali, Indonesia. The sites were located approximately 60 km north of the Bali Province capital city of Denpasar in an area named Bedugul. Those three sites were Mt. Mangu (forest area east of Beratan lake, forest area west of Buyan lake and forest area south of Tamblingan lake. There were 44, 29, and 21 tree species of 14, 19, 14 families with Shannon Diversity Index (H’ of 2.87, 2.64 and 1.69 respectively. Carbon stock average of above ground tree biomass from these sites were 214.2, 693.0 and 749.1 ton.ha-1 respectively. Tree species with top Summed Dominance Ratio (SDR in each of those sites were Platea latifolia in Mt. Mangu, Planchonella sp. in Buyan, and Tabernaemontana macrocarpa in Tamblingan. Average carbon content of these three species were 493.25, 12,876.26 and 40.35 kg.ha-1 respectively.

  11. A multiproxy study of Holocene water-depth and environmental changes in Lake St Ana, Eastern Carpathian Mountains, Romania

    Science.gov (United States)

    Magyari, E. K.; Buczkó, K.; Braun, M.; Jakab, G.

    2009-04-01

    This study presents the results of a multi-disciplinary investigation carried out on the sediment of a crater lake (Lake Saint Ana, 950 m a.s.l.) from the Eastern Carpathian Mountains. The lake is set in a base-poor volcanic environment with oligotrophic and slightly acidic water. Loss-on-ignition, major and trace element, pollen, plant macrofossil and siliceous algae analyses were used to reconstruct Holocene environmental and water-depth changes. Diatom-based transfer functions were applied to estimate the lake's trophic status and pH, while reconstruction of the water-depth changes was based on the plant macrofossil and diatom records. The lowest Holocene water-depths were found between 9,000 and 7,400 calibrated BP years, when the crater was occupied by Sphagnum-bog and bog-pools. The major trend from 7,400 years BP was a gradual increase, but the basin was still dominated by poor-fen and poor fen-pools. Significant increases in water-depth, and meso/oligotrophic lake conditions were found from 5,350(1), 3,300(2) and 2,700 years BP. Of these, the first two coincided with major terrestrial vegetation changes, namely the establishment of Carpinus betulus on the crater slope (1), and the replacement of the lakeshore Picea abies forest by Fagus sylvatica (2). The chemical record clearly indicated significant soil changes along with the canopy changes (from coniferous to deciduous), that in turn led to increased in-lake productivity and pH. A further increase in water-depth around 2,700 years BP resulted in stable thermal stratification and hypolimnetic anoxia that via P-release further increased in-lake productivity and eventually led to phytoplankton blooms with large populations of Scenedesmus cf. S. brasiliensis. High productivity was depressed by anthropogenic lakeshore forest clearances commencing from ca. 1,000 years BP that led to the re-establishment of Picea abies on the lakeshore and consequent acidification of the lake-water. On the whole, these data

  12. Contents of some heavy metals in plants from Saginaw Bay (Lake Huron) and some small lakes in wilderness areas of Michigan's Upper Peninsula as analyzed by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wells, J.R. (Cranbrook Institute of Science, Bloomfield Hill (USA)); Kaufman, P.B.; Jones, J.D.; Estabrook, G.F.; Ghosheh, N.S. (Michigan Univ., Ann Arbor (USA); Michigan Univ., Ann Arbor (USA). Michigan Memorial Phoenix Project; Eastern Michigan University, Ypsilanti (USA). Department of Biology)

    1982-01-01

    The highest concentrations of heavy metals occured in plants collected near the mouth of the Saginaw River. The alga, Cladophora sp., and the flowering plant, Typha augustifolia (cat-tail), are notable for the high concentration of heavy metals. In addition, several other species that were sampled from small lakes in Michigan's Upper Peninsula contained higher concentrations of certain metals (Ba, Cr, Rb) than from any samples obtained from Saginaw Bay. Different organs of the same species, or of the same plant, such as cut-tail, vary widely in concentrations of the same element. A computer-derived analysis of our data is presented, and the implications of our results as they relate to pollution by heavy metals in fresh-water lakes is discussed.

  13. MORPHO-BATHYMETRIC PARAMETERS OF RECESS CRUCII LAKE (STÂNIŞOAREI MOUNTAINS

    Directory of Open Access Journals (Sweden)

    ALIN MIHU-PINTILIE

    2012-03-01

    Full Text Available Morpho-bathymetric parameters of recess Crucii Lake (Stânişoarei Mountains. Crucii Lake from Stânişoarei Mountains was formed in 1978 as a result of riverbed dam Cuejdel after a landslide triggered on the western slope of Muncelul Peak. The event led initially to a small accumulation of 250-300 acvatoriu m, 25-30 m wide and 4-5 m maximum depth. In the summer of 1991 following the construction of a forest road in the flysch, and amid a high humid conditions, the slide was reactivated, leading to the formation of the largest natural dam lake in Romania. It has a length of 1 km, area of 12.2 ha, maximum depth of 16 m and a water volume of ca. 907.000 m3. Morphometric and morpho-bathymetric measurements performed in the summer of 2011, with the help of the integrated 1.200 GPS of Station Leica System 1.200 surveying measurements and bathymetric measurements Valeyport Ecosounder Midas showed new values for the morpho-bathymetric parameters. Among them stands out: 13,95 ha area, perimeter 2801,1 m, maximum length of 1004,82 m, 282,6 m maximum width, maximum depth 16,45 m. To achieve the numerical model of the lake basin were more than 45.000 points bali reading, with equidistance of 0,25 m. The scale of detail work aimed to draw up a proper database to eliminate suspicions about the old analytical methods inaccuracies. At the same time was studied the evolution of the lake’s basin in the context of relatively recent geomorphological changes.

  14. Three Dimensional Seismic Tomography of the Shallow Subsurface Structure Under the Meihua Lake in Ilan, Northeastern Taiwan

    Science.gov (United States)

    Shih, R.

    2008-12-01

    The island of Taiwan is located at an ongoing collision boundary between two plates. The Philippine Sea plate and the Eurasian plate collided at the Longitudinal Valley of eastern Taiwan, and the Philippine Sea plate subducted northward beneath the Eurasian plate along the Ryukyu trench in eastern Taiwan at the Hualien area. Further northward in the island, the opening Okinawa trough ended at the Ilan area in northeastern Taiwan. The Ilan area is over populated and potentially able to produce large earthquake; however, since that are is densely covered with forests, due to lack of geologic and geomorphologic evidences, known active faults are still unclear. Recently, a series of topographic offsets of several meters distributed in a zone were found by using the LiDAR DTM data, indicating active normal faulting was activated in the past. Besides, several small sag ponds were mapped to support the active normal faulting activities. Later on, core borings in one of the small ponds (the Meihua Lake, diameter of about 700m) were conducted and the records showed obvious difference of depths in the adjacent boreholes at a very short distance. In order to realize the variation of the distribution of sediments under the Meihua Lake, we conducted a 3d seismic tomography survey at the lake, hopefully to help to verify the faults. In this paper, we will show results of using a 120-channel shallow seismic recording system for mapping the shallow subsurface structure of sediments under the Meihua Lake. During the experiment, we deployed the geophone groups of three geophones at every 6m along the bank of the lake and fired the shots at every 80m around the lake. An impactor of energy 2200 joule per shot was used as a seismic source. We stacked the energy at each shot point around 60 times for receiving clear signals. Since the total extension of recording system is 720m, about one third of the perimeter around the lake, 2,200m, we moved the geophone deployments 3 times to

  15. Applying the SWAT hydrologic model on a watershed containing forested karst.

    Science.gov (United States)

    Devendra M. Amatya; Amy E. Edwards

    2009-01-01

    The US Forest Service Center for Forested Wetlands Research is working on a South Carolina Department of Health and Environmental Control (SC DHEC)'s Section 319 Grant Program funded Total Maximum Daily Load (TMDL) project for the watershed of Chapel Branch Creek (CBC) draining to Lake Marion in Santee, South Carolina (Fig. 1)....

  16. Social-ecological dynamics of the small scale fisheries in Sundarban Mangrove Forest, Bangladesh

    OpenAIRE

    Mohammad Mojibul Hoque Mozumder; Md. Mostafa Shamsuzzaman; Md. Rashed-Un-Nabi; Ehsanul Karim

    2018-01-01

    The Sundarban Mangrove Forest (SMF) is an intricate ecosystem containing the most varied and profuse natural resources of Bangladesh. This study presents empirical research, based on primary and secondary data, regarding the social-ecological system (SES), social-ecological dynamics, different stakeholders and relevant management policies of small-scale or artisanal fisheries such as the SMF; showing how, despite extensive diversification, the livelihood activities of the artisanal fishers in...

  17. The importance of lake-specific characteristics for water quality across the continental United States.

    Science.gov (United States)

    Read, Emily K; Patil, Vijay P; Oliver, Samantha K; Hetherington, Amy L; Brentrup, Jennifer A; Zwart, Jacob A; Winters, Kirsten M; Corman, Jessica R; Nodine, Emily R; Woolway, R Iestyn; Dugan, Hilary A; Jaimes, Aline; Santoso, Arianto B; Hong, Grace S; Winslow, Luke A; Hanson, Paul C; Weathers, Kathleen C

    2015-06-01

    Lake water quality is affected by local and regional drivers, including lake physical characteristics, hydrology, landscape position, land cover, land use, geology, and climate. Here, we demonstrate the utility of hypothesis testing within the landscape limnology framework using a random forest algorithm on a national-scale, spatially explicit data set, the United States Environmental Protection Agency's 2007 National Lakes Assessment. For 1026 lakes, we tested the relative importance of water quality drivers across spatial scales, the importance of hydrologic connectivity in mediating water quality drivers, and how the importance of both spatial scale and connectivity differ across response variables for five important in-lake water quality metrics (total phosphorus, total nitrogen, dissolved organic carbon, turbidity, and conductivity). By modeling the effect of water quality predictors at different spatial scales, we found that lake-specific characteristics (e.g., depth, sediment area-to-volume ratio) were important for explaining water quality (54-60% variance explained), and that regionalization schemes were much less effective than lake specific metrics (28-39% variance explained). Basin-scale land use and land cover explained between 45-62% of variance, and forest cover and agricultural land uses were among the most important basin-scale predictors. Water quality drivers did not operate independently; in some cases, hydrologic connectivity (the presence of upstream surface water features) mediated the effect of regional-scale drivers. For example, for water quality in lakes with upstream lakes, regional classification schemes were much less effective predictors than lake-specific variables, in contrast to lakes with no upstream lakes or with no surface inflows. At the scale of the continental United States, conductivity was explained by drivers operating at larger spatial scales than for other water quality responses. The current regulatory practice of using

  18. Initial response of small ground-dwelling mammals to forest alternative buffers along headwater streams in the Washington Coast Range, USA

    Science.gov (United States)

    Randall J. Wilk; Martin G. Raphael; Christopher S. Nations; Jeffrey D. Ricklefs

    2010-01-01

    We assessed the short-term effects of alternative designs of forested buffer treatments along headwater streams on small ground-dwelling mammals in managed forests in western Washington, USA. Over three summers (one pretreatment and two posttreatment), we trapped 19 mammalian species along 23 streams in the northern Coast Range. We compared faunal communities in...

  19. Natural radiation dose of small mammalians in beech forest of Rokkasho, Japan

    International Nuclear Information System (INIS)

    Ohtsuka, Yoshihito; Iyogi, Takashi; Takaku, Yuichi; Hisamatsu, Shun'ichi

    2008-01-01

    Full text: Protection of the environment itself from radiation hazards is recognized as important as that of humans. Actual data on the background natural radiation dose, which is necessary to evaluate the effect of radiation, are very few, especially in the terrestrial environment. Forests around the Japan's first large scale nuclear fuel reprocessing plant in Rokkasho were selected as the research field for evaluating the background natural radiation to the environment. Data observed will be used in future for the comparison with the radiation dose from radionuclides released from the plant. Small mammalians, mouse (Apodeums argentus) and mole (Urotrichus talpoides), were selected as representative animals of the forests in this study, and it was planned to measure their radiation doses from natural sources; environmental γ-rays, Rn and internal radionuclides. The forests around the plant were classified into three types: beech, oak and coniferous. We have been measuring the natural radiation to the mammalians in each of those forests one by one and report the data for the beech forest here. The mammalians caught in traps in the beech forest during June-October, 2006 were analyzed for their natural radionuclides burdens ( 210 Pb, 210 Po, 40 K, 87 Rb, 226 Ra, 238 U and 232 Th) in 11 organs and carcass. Radiation dose rates from environmental γ-rays and atmospheric concentration of Rn in the forest were also measured during August-December, 2006. Mean internal dose rates of mouse and mole caught in June, 2006 were estimated to be 0.036 μGy h -1 and 0.28 μGy h -1 , respectively, from mean concentrations of the nuclides in a total body and internal dose conversion coefficients by FASSET. The difference of the dose between the two mammalian species was attributed to higher contribution of 210 Po in mole, in which dose reached 0.25 μGy h -1 in contrast to that in mouse of 0.016 μGy h -1 . The concentration of 210 Po in kidney of mole (0.37 Bq g -1 wet) was

  20. Lake Roosevelt Fisheries Evaluation Program; Meadow Creek vs. Lake Whatcom Stock Kokanee Salmon Investigations in Lake Roosevelt, Annual Report 2002.

    Energy Technology Data Exchange (ETDEWEB)

    McLellan, Holly

    2003-03-01

    Lake Whatcom, Washington kokanee have been stocked in Lake Roosevelt since 1987 with the primary objective of creating a self-sustaining fishery. Success has been limited by low recruitment to the fishery, low adult returns to hatcheries, and a skewed sex ratio. It was hypothesized that a stock native to the upper Columbia River might perform better than the coastal Lake Whatcom stock. Kokanee from Meadow Creek, a tributary of Kootenay Lake, British Columbia were selected as an alternative stock. Post smolts from each stock were released from Sherman Creek Hatchery in late June 2000 and repeated in 2001. Stock performance was evaluated using three measures; (1) number of returns to Sherman Creek, the primary egg collection facility, (2) the number of returns to 86 tributaries sampled and, (3) the number of returns to the creel. In two repeated experiments, neither Meadow Creek or Lake Whatcom kokanee appeared to be capable of providing a run of three-year old spawners to sustain stocking efforts. Less than 10 three-years olds from either stock were collected during the study period. Chi-square analysis indicated age two Meadow Creek kokanee returned to Sherman Creek and to other tributaries in significantly higher numbers when compared to the Lake Whatcom stock in both 2000 and 2001. However, preliminary data from the Spokane Tribe of Indians indicated that a large number of both stocks were precocial before they were stocked. The small number of hatchery three-year olds collected indicated that the current hatchery rearing and stocking methods will continue to produce a limited jacking run largely composed of precocious males and a small number of three-year olds. No kokanee from the study were collected during standard lake wide creel surveys. Supplemental creel data, including fishing derbies, test fisheries, and angler diaries, indicated anglers harvested two-year-old hatchery kokanee a month after release. The majority of the two-year old kokanee harvested

  1. Lichenized Ascomycetes (Lichenes of the Choszczno Lake District

    Directory of Open Access Journals (Sweden)

    Ludwik Lipnicki

    2014-08-01

    Full Text Available The paper includes the list of 184 species of Lichens stated in the area of Choszczno Lake District. It gives the ecological conditions of their occurrence and the number of sites. Theendangered lichens growing in the forest-bereft regions which were under the strong influence of factors included by intensive agriculture were presented.

  2. Hydrological and solute budgets of Lake Qinghai, the largest lake on the Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Zhangdong [Chinese Academy of Sciences (CAS), Beijing (China); National Cheng Kung Univ., Tainan City (Taiwan); You, Chen-Feng [National Cheng Kung Univ., Tainan City (Taiwan); Wang, Yi [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shi, Yuewei [Bureau of Hydrology and Water Resources of Qinghai Province, Xining (China)

    2009-12-04

    Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca 2+ and DIC for river waters and groundwater. Groundwater contribution to major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4–44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na+, Cl-, Mg 2+ , and K+ in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca 2+ into the bottom sediments of the lake, resulting in very low Ca 2+ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past.

  3. The “anomalous cedar trees” of Lake Ashi, Hakone Volcano, Japan

    Science.gov (United States)

    Oki, Y.

    1984-01-01

    On the bottom of Lake Ashi at Hakone, Japan, there stand great trees that, since ancient times, have been widely known as the "Anomalous Cedar Trees" of Ashi. It is not known why these trees grow on the bottom of the lake, and it remains one of the mysteries of Hakone. It was formerly thought that, at the time Lake Ashi was born, a great forest of cedar trees which was growing in the caldera of the volcano sank into the water. From radioactive carbon dating techniques, it is known that a steam explosion in the Kami Mountains created the caldera approximately 3,000 years ago. The age of the "Anomalous Cedars" is placed at approximately. 

  4. An improved active contour model for glacial lake extraction

    Science.gov (United States)

    Zhao, H.; Chen, F.; Zhang, M.

    2017-12-01

    Active contour model is a widely used method in visual tracking and image segmentation. Under the driven of objective function, the initial curve defined in active contour model will evolve to a stable condition - a desired result in given image. As a typical region-based active contour model, C-V model has a good effect on weak boundaries detection and anti noise ability which shows great potential in glacial lake extraction. Glacial lake is a sensitive indicator for reflecting global climate change, therefore accurate delineate glacial lake boundaries is essential to evaluate hydrologic environment and living environment. However, the current method in glacial lake extraction mainly contains water index method and recognition classification method are diffcult to directly applied in large scale glacial lake extraction due to the diversity of glacial lakes and masses impacted factors in the image, such as image noise, shadows, snow and ice, etc. Regarding the abovementioned advantanges of C-V model and diffcults in glacial lake extraction, we introduce the signed pressure force function to improve the C-V model for adapting to processing of glacial lake extraction. To inspect the effect of glacial lake extraction results, three typical glacial lake development sites were selected, include Altai mountains, Centre Himalayas, South-eastern Tibet, and Landsat8 OLI imagery was conducted as experiment data source, Google earth imagery as reference data for varifying the results. The experiment consequence suggests that improved active contour model we proposed can effectively discriminate the glacial lakes from complex backgound with a higher Kappa Coefficient - 0.895, especially in some small glacial lakes which belongs to weak information in the image. Our finding provide a new approach to improved accuracy under the condition of large proportion of small glacial lakes and the possibility for automated glacial lake mapping in large-scale area.

  5. Modeling climate and fuel reduction impacts on mixed-conifer forest carbon stocks in the Sierra Nevada, California

    Science.gov (United States)

    Matthew D. Hurteau; Timothy A. Robards; Donald Stevens; David Saah; Malcolm North; George W. Koch

    2014-01-01

    Quantifying the impacts of changing climatic conditions on forest growth is integral to estimating future forest carbon balance. We used a growth-and-yield model, modified for climate sensitivity, to quantify the effects of altered climate on mixed-conifer forest growth in the Lake Tahoe Basin, California. Estimates of forest growth and live tree carbon stocks were...

  6. Radiochemical tools at the experimental lakes area (ELA) in Ontario, Canada

    International Nuclear Information System (INIS)

    Pfitzner, J.; Brunskill, G.

    1998-01-01

    Full text: For over 20 years, Canadian research scientists have used radiochemical tracers added to remote and pristine lakes to study physical, chemical, and biological processes that could not be easily quantified by other methods. Lakes have also been manipulated by experimentally altering the hydrological cycle, chemical composition, and species of fish in selected lakes, and using companion lakes as controls. Varying additions of organic carbon, N, and P have been done, and the exchange rate of carbon dioxide between the atmosphere and water was estimated using radon evasion rates from radium spikes in the lake water. Multinuclide spikes were done to follow the path of mine waste elements through the food chain and sediment accumulation. Lakes were experimentally acidified with HCl and HNO 3 and H 2 SO 4 to simulate acid rain, and to study natural buffering capacity of the hydrological cycle. Some of this research has been used to legislate pollution control in the St. Laurence Great Lakes and across Canada and USA. ELA research team spirit has survived several forest fires, bear attacks on the kitchen, massive cut-backs in funding and reduction in staff of Fisheries and Ocean Canada

  7. An initial analysis of LANDSAT 4 Thematic Mapper data for the classification of agricultural, forested wetland, and urban land covers

    Science.gov (United States)

    Quattrochi, D. A.; Anderson, J. E.; Brannon, D. P.; Hill, C. L.

    1982-01-01

    An initial analysis of LANDSAT 4 thematic mapper (TM) data for the delineation and classification of agricultural, forested wetland, and urban land covers was conducted. A study area in Poinsett County, Arkansas was used to evaluate a classification of agricultural lands derived from multitemporal LANDSAT multispectral scanner (MSS) data in comparison with a classification of TM data for the same area. Data over Reelfoot Lake in northwestern Tennessee were utilized to evaluate the TM for delineating forested wetland species. A classification of the study area was assessed for accuracy in discriminating five forested wetland categories. Finally, the TM data were used to identify urban features within a small city. A computer generated classification of Union City, Tennessee was analyzed for accuracy in delineating urban land covers. An evaluation of digitally enhanced TM data using principal components analysis to facilitate photointerpretation of urban features was also performed.

  8. Modeling forest mortality caused by drought stress: implications for climate change

    Science.gov (United States)

    Eric J Gustafson; Brian R. Sturtevant

    2013-01-01

    Climate change is expected to affect forest landscape dynamics in many ways, but it is possible that the most important direct impact of climate change will be drought stress. We combined data from weather stations and forest inventory plots (FIA) across the upper Great Lakes region (USA) to study the relationship between measures of drought stress and mortality for...

  9. Short-term responses to watershed logging on biomass mercury and methylmercury accumulation by periphyton in boreal lakes

    Energy Technology Data Exchange (ETDEWEB)

    Desrosiers, M.; Planas, D. [Quebec Univ., Montreal, PQ (Canada). Dept. de sciences biologiques; Mucci, A. [McGill Univ., Montreal, PQ (Canada). Dept. of Earth and Planetary Sciences

    2006-08-15

    Increased timber harvesting in the boreal regions of Quebec may have a significant impact on aquatic ecosystems. Watershed disturbances such as logging increase chemical loading to lakes. Soil in the Canadian Shield readily adsorbs and accumulates mercury (Hg) from atmospheric deposition. Forest watersheds serve as large reservoirs of Hg that shed their metal load when soil and land hydrology are disrupted. This paper presented the results of a study evaluating the impact of logging on periphyton algal biomass and dry mass. The study also evaluated the impact of total mercury (THG) and methylmercury (MeHg) accumulation in the littoral zone of the boreal lakes. A before-after control-impact (BACI) sample design was applied that required data from control and target sites sampled both before and after the disturbances. The study was carried out on 18 boreal lakes located in the Grenville geological province. Eight lakes had their watersheds logged over 15 to 79 per cent of their area. A further 10 lakes were used as control sites to document interannual variations. The project used water quality and physiographic data acquired by research groups within the Sustainable Forest Management Network. Fourteen study lakes were sampled once a year during 2 consecutive ice-free seasons before and after logging, and another 4 lakes were sampled 2 years after logging. Significant decreases in algal biomass and increases in MeHg concentrations in periphyton mats in a majority of the harvested watershed lakes were detected. The increases may have a significant impact on organisms of higher trophic levels as they are at the base of the food web. Results suggested that the observed decrease in periphyton biomass combined with the increase in MeHg accumulation may magnify the impact of logging activities on fish and other aquatic predators. Two years after logging, it was observed that MeHg concentrations were still increasing. It was concluded that further research is needed

  10. Consequences of radioactive deposition on aquatic environments

    International Nuclear Information System (INIS)

    Suolanen, V.

    1994-12-01

    The publication concentrates on the analyses of the main effects of radioactive deposition on Nordic aquatic environments. A modelling approach is applied for predicting the temporal behaviour of concentrations in fish of inland freshwater ecosystems. The observed values are considered in parallel with the calculations. The time-integrated consequences, the radiation doses are estimated for the relatively significant dose pathways. After a preliminary study of various lake environments in Nordic countries, three representative examples of lake systems were selected for closer consideration: small forest lake, medium-sized forest lake and mountain lake. The effects of changes in the trophic levels of lakes are also tentatively accounted for. The results of the analyses indicate that the radiological consequences of shallow forest lakes are greater than those of mountain lakes which usually have shorter turnover times compared to forest lakes. In long-term consideration, the fish ingestion pathway may in general become important and, in addition to the external exposure, has a high contribution to the expected doses. (orig.) (8 refs., 11 figs., 9 tabs.)

  11. Nitrous oxide and methane exchange in two small temperate forest catchments - effects of hydrological gradients and implications for global warming potentials of forest soils

    DEFF Research Database (Denmark)

    Christiansen, Jesper Riis; Vesterdal, Lars; Gundersen, Per

    2012-01-01

    half the catchment area at both sites, the global warming potential (GWP) derived from N2O and CH4 was more than doubled when accounting for these wet areas in the catchments. The results stress the importance of wet soils in assessments of forest soil global warming potentials, as even small...

  12. Relating demographic characteristics of a small mammal to remotely sensed forest-stand condition.

    Directory of Open Access Journals (Sweden)

    Hania Lada

    Full Text Available Many ecological systems around the world are changing rapidly in response to direct (land-use change and indirect (climate change human actions. We need tools to assess dynamically, and over appropriate management scales, condition of ecosystems and their responses to potential mitigation of pressures. Using a validated model, we determined whether stand condition of floodplain forests is related to densities of a small mammal (a carnivorous marsupial, Antechinus flavipes in 60,000 ha of extant river red gum (Eucalyptus camaldulensis forests in south-eastern Australia in 2004, 2005 and 2011. Stand condition was assessed remotely using models built from ground assessments of stand condition and satellite-derived reflectance. Other covariates, such as volumes of fallen timber, distances to floods, rainfall and life stages were included in the model. Trapping of animals was conducted at 272 plots (0.25 ha across the region. Densities of second-year females (i.e. females that had survived to a second breeding year and of second-year females with suckled teats (i.e. inferred to have been successful mothers were higher in stands with the highest condition. There was no evidence of a relationship with stand condition for males or all females. These outcomes show that remotely-sensed estimates of stand condition (here floodplain forests are relatable to some demographic characteristics of a small mammal species, and may provide useful information about the capacity of ecosystems to support animal populations. Over-regulation of large, lowland rivers has led to declines in many facets of floodplain function. If management of water resources continues as it has in recent decades, then our results suggest that there will be further deterioration in stand condition and a decreased capacity for female yellow-footed antechinuses to breed multiple times.

  13. Mapping forest canopy disturbance in the Upper Great Lakes, USA

    Science.gov (United States)

    James D. Garner; Mark D. Nelson; Brian G. Tavernia; Charles H. (Hobie) Perry; Ian W. Housman

    2015-01-01

    A map of forest canopy disturbance was generated for Michigan, Wisconsin, and most of Minnesota using 42 Landsat time series stacks (LTSS) and a vegetation change tracker (VCTw) algorithm. Corresponding winter imagery was used to reduce commission errors of forest disturbance by identifying areas of persistent snow cover. The resulting disturbance age map was classed...

  14. Soil properties and aspen development five years after compaction and forest floor removal

    Science.gov (United States)

    Douglas M. Stone; John D. Elioff

    1998-01-01

    Forest management activities that decrease soil porosity and remove organic matter have been associated with declines in site productivity. In the northern Lake States region, research is in progress in the aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forest type to determine effects of soil compaction and organic...

  15. Microbial ecology of acid strip mine lakes in southern Indiana

    International Nuclear Information System (INIS)

    Gyure, R.A.

    1986-01-01

    In this study, the author examined the limnology and microbial ecology of two acid strip mine lakes in the Greene-Sullivan State Forest near Dugger, Indiana. Reservoir 29 is a larger lake (225 ha) with water column pH of 2.7 and sediment pH of 3.8. Lake B, a smaller (20 ha) lake to the south of Reservoir 29, also has an acidic water column (pH 3.4) but more neutral sediments (pH 6.2). Both have very high sulfate concentrations: 20-30 mM in the water column and as high as 100 mM in the hypolimnion of Lake B. Low allochthonous carbon and nutrient input characterize these lakes as oligotrophic, although algal biomass is higher than would be expected for this trophic status. In both lakes, algal populations are not diverse, with a few species of single-celled Chlorophyta and euglenoids dominating. Algal biomass is concentrated in a thin 10 cm layer at the hypolimnion/metalimnion interface, although light intensity at this depth is low and severely limits productivity. Bacterial activity based on 14 C-glucose incorporation is highest in the hypolimnion of both lakes, and sulfate-reduction is a dominant process in the sediments. Rates of sulfate-reduction compare with those in other freshwater environments, but are not as high as rates measured in high sulfate systems like saltmarsh and marine sediments

  16. Contaminant Monitoring Strategy for Henrys Lake, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    John S. Irving; R. P. Breckenridge

    1992-12-01

    Henrys Lake, located in southeastern Idaho, is a large, shallow lake (6,600 acres, {approx} 17.1 feet maximum depth) located at 6,472 feet elevation in Fremont Co., Idaho at the headwaters of the Henrys Fork of the Snake River. The upper watershed is comprised of high mountains of the Targhee National Forest and the lakeshore is surrounded by extensive flats and wetlands, which are mostly privately owned. The lake has been dammed since 1922, and the upper 12 feet of the lake waters are allocated for downriver use. Henrys Lake is a naturally productive lake supporting a nationally recognized ''Blue Ribbon'' trout fishery. There is concern that increasing housing development and cattle grazing may accelerate eutrophication and result in winter and early spring fish kills. There has not been a recent thorough assessment of lake water quality. However, the Department of Environmental Quality (DEQ) is currently conducting a study of water quality on Henrys Lake and tributary streams. Septic systems and lawn runoff from housing developments on the north, west, and southwest shores could potentially contribute to the nutrient enrichment of the lake. Many houses are on steep hillsides where runoff from lawns, driveways, etc. drain into wetland flats along the lake or directly into the lake. In addition, seepage from septic systems (drainfields) drain directly into the wetlands enter groundwater areas that seep into the lake. Cattle grazing along the lake margin, riparian areas, and uplands is likely accelerating erosion and nutrient enrichment. Also, cattle grazing along riparian areas likely adds to nutrient enrichment of the lake through subsurface flow and direct runoff. Stream bank and lakeshore erosion may also accelerate eutrophication by increasing the sedimentation of the lake. Approximately nine streams feed the lake (see map), but flows are often severely reduced or completely eliminated due to irrigation diversion. In addition, subsurface

  17. Palms, peccaries and perturbations: widespread effects of small-scale disturbance in tropical forests

    Directory of Open Access Journals (Sweden)

    Queenborough Simon A

    2012-03-01

    Full Text Available Abstract Background Disturbance is an important process structuring ecosystems worldwide and has long been thought to be a significant driver of diversity and dynamics. In forests, most studies of disturbance have focused on large-scale disturbance such as hurricanes or tree-falls. However, smaller sub-canopy disturbances could also have significant impacts on community structure. One such sub-canopy disturbance in tropical forests is abscising leaves of large arborescent palm (Arececeae trees. These leaves can weigh up to 15 kg and cause physical damage and mortality to juvenile plants. Previous studies examining this question suffered from the use of static data at small spatial scales. Here we use data from a large permanent forest plot combined with dynamic data on the survival and growth of > 66,000 individuals over a seven-year period to address whether falling palm fronds do impact neighboring seedling and sapling communities, or whether there is an interaction between the palms and peccaries rooting for fallen palm fruit in the same area as falling leaves. We tested the wider generalisation of these hypotheses by comparing seedling and sapling survival under fruiting and non-fruiting trees in another family, the Myristicaceae. Results We found a spatially-restricted but significant effect of large arborescent fruiting palms on the spatial structure, population dynamics and species diversity of neighbouring sapling and seedling communities. However, these effects were not found around slightly smaller non-fruiting palm trees, suggesting it is seed predators such as peccaries rather than falling leaves that impact on the communities around palm trees. Conversely, this hypothesis was not supported in data from other edible species, such as those in the family Myristicaceae. Conclusions Given the abundance of arborescent palm trees in Amazonian forests, it is reasonable to conclude that their presence does have a significant, if spatially

  18. Palms, peccaries and perturbations: widespread effects of small-scale disturbance in tropical forests.

    Science.gov (United States)

    Queenborough, Simon A; Metz, Margaret R; Wiegand, Thorsten; Valencia, Renato

    2012-03-19

    Disturbance is an important process structuring ecosystems worldwide and has long been thought to be a significant driver of diversity and dynamics. In forests, most studies of disturbance have focused on large-scale disturbance such as hurricanes or tree-falls. However, smaller sub-canopy disturbances could also have significant impacts on community structure. One such sub-canopy disturbance in tropical forests is abscising leaves of large arborescent palm (Arececeae) trees. These leaves can weigh up to 15 kg and cause physical damage and mortality to juvenile plants. Previous studies examining this question suffered from the use of static data at small spatial scales. Here we use data from a large permanent forest plot combined with dynamic data on the survival and growth of > 66,000 individuals over a seven-year period to address whether falling palm fronds do impact neighboring seedling and sapling communities, or whether there is an interaction between the palms and peccaries rooting for fallen palm fruit in the same area as falling leaves. We tested the wider generalisation of these hypotheses by comparing seedling and sapling survival under fruiting and non-fruiting trees in another family, the Myristicaceae. We found a spatially-restricted but significant effect of large arborescent fruiting palms on the spatial structure, population dynamics and species diversity of neighbouring sapling and seedling communities. However, these effects were not found around slightly smaller non-fruiting palm trees, suggesting it is seed predators such as peccaries rather than falling leaves that impact on the communities around palm trees. Conversely, this hypothesis was not supported in data from other edible species, such as those in the family Myristicaceae. Given the abundance of arborescent palm trees in Amazonian forests, it is reasonable to conclude that their presence does have a significant, if spatially-restricted, impact on juvenile plants, most likely on the

  19. Morphological parameters of the norway maple small undergrowthin forests of the Novgorod-Sivers’k Polissia

    Directory of Open Access Journals (Sweden)

    V. G. Skliar

    2012-02-01

    Full Text Available The size characteristics of the Norway maple small undergrowth in different association groups of the forests of Novgorod-Sivers’k Polissia are аnalyzed. As the trophicity of soil increases the values of static metric and dynamic morphoparameters of the undergrowth upsurge. And on the contrary, the values reduced with the growth of the forest overstory density and the projective cover of the herb-shrub layer. It is shown that in different plant communities the Norway maple undergrowth is characterised by specific morphological structure. The communal habitat of the group of Querceta convallariosa associations conforms with the parameters of ecocoenotical optimum, which conditions are most favourable for successful growth of the maple young generation.

  20. Simulating Lake-Groundwater Interactions During Decadal Climate Cycles: Accounting For Variable Lake Area In The Watershed

    Science.gov (United States)

    Virdi, M. L.; Lee, T. M.

    2009-12-01

    The volume and extent of a lake within the topo-bathymetry of a watershed can change substantially during wetter and drier climate cycles, altering the interaction of the lake with the groundwater flow system. Lake Starr and other seepage lakes in the permeable sandhills of central Florida are vulnerable to climate changes as they rely exclusively on rainfall and groundwater for inflows in a setting where annual rainfall and recharge vary widely. The groundwater inflow typically arrives from a small catchment area bordering the lake. The sinkhole origin of these lakes combined with groundwater pumping from underlying aquifers further complicate groundwater interactions. Understanding the lake-groundwater interactions and their effects on lake stage over multi-decadal climate cycles is needed to manage groundwater pumping and public expectation about future lake levels. The interdependence between climate, recharge, changing lake area and the groundwater catchment pose unique challenges to simulating lake-groundwater interactions. During the 10-year study period, Lake Starr stage fluctuated more than 13 feet and the lake surface area receded and expanded from 96 acres to 148 acres over drier and wetter years that included hurricanes, two El Nino events and a La Nina event. The recently developed Unsaturated Zone Flow (UZF1) and Lake (LAK7) packages for MODFLOW-2005 were used to simulate the changing lake sizes and the extent of the groundwater catchment contributing flow to the lake. The lake area was discretized to occupy the largest surface area at the highest observed stage and then allowed to change size. Lake cells convert to land cells and receive infiltration as receding lake area exposes the underlying unsaturated zone to rainfall and recharge. The unique model conceptualization also made it possible to capture the dynamic size of the groundwater catchment contributing to lake inflows, as the surface area and volume of the lake changed during the study

  1. Changes in lake level and trophy at Lake Vrana, a large karstic lake on the Island of Cres (Croatia, with respect to palaeoclimate and anthropogenic impacts during the last approx. 16,000 years

    Directory of Open Access Journals (Sweden)

    Ante BARIĆ

    2000-08-01

    Full Text Available A multi-proxy approach study (cladocerans, diatoms, geochemistry, plant macrofossils, pollen, was performed on a sediment core from Lake Vrana (Vransko Jezero, a large and deep karstic lake on the northern Adriatic island of Cres, Croatia. Considerable lake-level changes occurred during the last approx. 16,000 years. The stratigraphic evidence suggests that periods of enhanced precipitation and the post-LGM rise in sea level were the main driving forces. The lake records indicate early human impacts. Sediment echo-sounding indicated that >25 m of lake sediments lies within the site, from which 5 m have been cored. Shallow lake stages occurred from 14.4 14C ky BP to early Holocene. Prior to Alleröd, interglacial sediments were redeposited, reflecting the influences of rising sea-level (forming a local groundwater barrier, a temporary increase in precipitation, and lake-level changes. There appears to be a hiatus in the sequence, for no sediments assignable to the Alleröd chronozone could be found. A discordance in the echo profile at the appropriate horizon in the sequence supports this interpretation. Groundwater level increased again at 10.6 ky BP (during Younger Dryas chronozone, a swamp vegetation formed, which gave way to a shallow lake. During the Preboreal chronozone, this freshwater lake persisted with fluctuating levels. The establishment and subsequent persistence of the present deep water lake at about 8.5 ky BP, correspond with findings of a pluvial period at the Dalmatian coast, which lasted from 8.4 to 6 ky BP. First human catchment disturbances were related to settlements of Neolithic or Bronze Age. The increase in summer drought, coupled with forest clearance during Illyrian times, are assumed to be responsible for the change towards present evergreen oak vegetation in the lake catchment. The intensification in land-use during Roman and post-Roman settlements caused a slight increase in the lake trophic level.

  2. Impact of wildfire on levels of mercury in forested watershed systems - Voyageurs National Park, Minnesota

    Science.gov (United States)

    Woodruff, Laurel G.; Sandheinrich, Mark B.; Brigham, Mark E.; Cannon, William F.

    2009-01-01

    Atmospheric deposition of mercury to remote lakes in mid-continental and eastern North America has increased approximately threefold since the mid-1800s (Swain and others, 1992; Fitzgerald and others, 1998; Engstrom and others, 2007). As a result, concerns for human and wildlife health related to mercury contamination have become widespread. Despite an apparent recent decline in atmospheric deposition of mercury in many areas of the Upper Midwest (Engstrom and Swain, 1997; Engstrom and others, 2007), lakes in which fish contain levels of mercury deemed unacceptable for human consumption and possibly unacceptable for fish-consuming wildlife are being detected with increasing frequency. In northern Minnesota, Voyageurs National Park (VNP) (fig. 1) protects a series of southern boreal lakes and wetlands situated on bedrock of the Precambrian Canadian Shield. Mercury contamination has become a significant resource issue within VNP as high concentrations of mercury in loons, bald eagle eaglets, grebes, northern pike, and other species of wildlife and fish have been found. The two most mercury-contaminated lakes in Minnesota, measured as methylmercury in northern pike (Esox lucius), are in VNP. Recent multidisciplinary U.S. Geological Survey (USGS) research demonstrated that the bulk of the mercury in lake waters, soils, and fish in VNP results from atmospheric deposition (Wiener and others, 2006). The study by Wiener and others (2006) showed that the spatial distribution of mercury in watershed soils, lake waters, and age-1 yellow perch (Perca flavescens) within the Park was highly variable. The majority of factors correlated for this earlier study suggested that mercury concentrations in lake waters and age-1 yellow perch reflected the influence of ecosystem processes that affected within-lake microbial production and abundance of methylmercury (Wiener and others, 2006), while the distribution of mercury in watershed soils seemed to be partially dependent on forest

  3. Competition and habitat selection in a forest-floor small mammal fauna

    Energy Technology Data Exchange (ETDEWEB)

    Dueser, R D [Univ. of Virginia, Charlottesville; Hallett, J G

    1980-01-01

    In a study of habitat exploitation in a forest-floor small mammal community, we have collected habitat and population data for Peromyscus leucopus, Ochrotomys nuttalli, and Tamias striatus. Using multiple regression analysis, researchers estimate the effects of habitat selection and competition on the local distributions of these species during three seasons. Each of the partial regression coefficients relating the density of an independent species to the density of the dependent species is negative. This result indicates that competition is pervasive among these species. Competitive ability and habitat selectivity both increase in the order Peromyscus-Tamias-Ochrotomys. Peromyscus is a poorly competitive habitat generalist, Ochrotomys is a strongly competitive habitat specialist, and Tamias is intermediate in both respects. The competitive hierarchy is stable between seasons. These results both confirm the conclusions reached in previous studies of this small mammal community and suggest the design of experiments to further clarify the mode and consequences of interaction between these species.

  4. Mercury methylation in Sphagnum moss mats and its association with sulfate-reducing bacteria in an acidic Adirondack forest lake wetland.

    Science.gov (United States)

    Yu, Ri-Qing; Adatto, Isaac; Montesdeoca, Mario R; Driscoll, Charles T; Hines, Mark E; Barkay, Tamar

    2010-12-01

    Processes leading to the bioaccumulation of methylmercury (MeHg) in northern wetlands are largely unknown. We have studied various ecological niches within a remote, acidic forested lake ecosystem in the southwestern Adirondacks, NY, to discover that mats comprised of Sphagnum moss were a hot spot for mercury (Hg) and MeHg accumulation (190.5 and 18.6 ng g⁻¹ dw, respectively). Furthermore, significantly higher potential methylation rates were measured in Sphagnum mats as compared with other sites within Sunday Lake's ecosystem. Although MPN estimates showed a low biomass of sulfate-reducing bacteria (SRB), 2.8 × 10⁴ cells mL⁻¹ in mat samples, evidence consisting of (1) a twofold stimulation of potential methylation by the addition of sulfate, (2) a significant decrease in Hg methylation in the presence of the sulfate reduction inhibitor molybdate, and (3) presence of dsrAB-like genes in mat DNA extracts, suggested that SRB were involved in Hg methylation. Sequencing of dsrB genes indicated that novel SRB, incomplete oxidizers including Desulfobulbus spp. and Desulfovibrio spp., and syntrophs dominated the sulfate-reducing guild in the Sphagnum moss mat. Sphagnum, a bryophyte dominating boreal peatlands, and its associated microbial communities appear to play an important role in the production and accumulation of MeHg in high-latitude ecosystems. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  5. Development of FVSOntario: A Forest Vegetation Simulator Variant and application software for Ontario

    Science.gov (United States)

    Murray E. Woods; Donald C. E. Robinson

    2008-01-01

    The Ontario Ministry of Natural Resources is leading a government-industry partnership to develop an Ontario variant of the Forest Vegetation Simulator (FVS). Based on the Lake States variant and the PrognosisBC user-interface, the FVSOntarioproject is motivated by a need to model the impacts of intensive forest management...

  6. Identification of ecological thresholds from variations in phytoplankton communities among lakes: contribution to the definition of environmental standards.

    Science.gov (United States)

    Roubeix, Vincent; Danis, Pierre-Alain; Feret, Thibaut; Baudoin, Jean-Marc

    2016-04-01

    In aquatic ecosystems, the identification of ecological thresholds may be useful for managers as it can help to diagnose ecosystem health and to identify key levers to enable the success of preservation and restoration measures. A recent statistical method, gradient forest, based on random forests, was used to detect thresholds of phytoplankton community change in lakes along different environmental gradients. It performs exploratory analyses of multivariate biological and environmental data to estimate the location and importance of community thresholds along gradients. The method was applied to a data set of 224 French lakes which were characterized by 29 environmental variables and the mean abundances of 196 phytoplankton species. Results showed the high importance of geographic variables for the prediction of species abundances at the scale of the study. A second analysis was performed on a subset of lakes defined by geographic thresholds and presenting a higher biological homogeneity. Community thresholds were identified for the most important physico-chemical variables including water transparency, total phosphorus, ammonia, nitrates, and dissolved organic carbon. Gradient forest appeared as a powerful method at a first exploratory step, to detect ecological thresholds at large spatial scale. The thresholds that were identified here must be reinforced by the separate analysis of other aquatic communities and may be used then to set protective environmental standards after consideration of natural variability among lakes.

  7. Whiting in Lake Michigan

    Science.gov (United States)

    2002-01-01

    Satellites provide a view from space of changes on the Earth's surface. This series of images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aboard the Orbview-2 satellite shows the dramatic change in the color of Lake Michigan during the summer. The bright color that appears in late summer is probably caused by calcium carbonate-chalk-in the water. Lake Michigan always has a lot of calcium carbonate in it because the floor of the lake is limestone. During most of the year the calcium carbonate remains dissolved in the cold water, but at the end of summer the lake warms up, lowering the solubility of calcium carbonate. As a result, the calcium carbonate precipitates out of the water, forming clouds of very small solid particles that appear as bright swirls from above. The phenomenon is appropriately called a whiting event. A similar event occured in 1999, but appears to have started later and subsided earlier. It is also possible that a bloom of the algae Microcystis is responsible for the color change, but unlikely because of Lake Michigan's depth and size. Microcystis blooms have occured in other lakes in the region, however. On the shore of the lake it is possible to see the cities of Chicago, Illinois, and Milwaukee, Wisconsin. Both appear as clusters of gray-brown pixels. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  8. Large or small? Rethinking China’s forest bioenergy policies

    International Nuclear Information System (INIS)

    Kahrl, Fredrich; Su, Yufang; Tennigkeit, Timm; Yang, Yongping; Xu, Jianchu

    2013-01-01

    China’s forest bioenergy policies are evolving against the backdrop of pressing national energy challenges similar to those faced by OECD countries, and chronic rural energy challenges more characteristic of developing countries. Modern forest bioenergy could contribute to solutions to both of these challenges. However, because of limitations in current technologies and institutions, significant policy and resource commitments would be required to make breakthroughs in either commercializing forest bioenergy or modernizing rural energy systems in China. Given the potential attention, funding, and resource trade-offs between these two goals, we provide an argument for why the focus of China’s forest bioenergy policy should initially be on addressing rural energy challenges. The paper concludes with a discussion on strategies for laying the groundwork for a modern, biomass-based energy infrastructure in rural China. -- Highlights: ► China’s bioenergy policy is at a crossroads. ► Trade-offs exist between forest bioenergy policy for urban and rural users in China. ► There are strong arguments for focusing forest bioenergy policy on rural areas. ► China’s rural energy policy should increasingly support modern energy carriers

  9. Methyl mercury concentrations in macroinvertebrates and fish from burned and undisturbed lakes on the Boreal Plain

    Energy Technology Data Exchange (ETDEWEB)

    Allen, E.W. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences; Prepas, E.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences; Lakehead Univ., Thunder Bay, ON (Canada). Faculty of Forest and the Forest Environment; Gabos, S.; Zhang, W. [Alberta Health and Wellness, Edmonton, AB (Canada); Strachan, W.M.J. [Environment Canada, Burlington, ON (Canada). National Water Research Inst.

    2005-09-01

    Methylmercury (MeHg) concentrations in macroinvertebrates and fish from 5 lakes in burned catchments in Alberta's Swan Hills region were compared with those from 5 reference lakes on the western Canadian Boreal Plain. The objective was to determine the effect of forest fire on the bioaccumulation of MeHg, a toxic pollutant. It was noted that lakes near the Alberta Special Waste Treatment Centre (ASWTC) have fish consumption advisories due to high mercury concentrations. In a separate comparison, MeHg concentrations in biota from a single lake were compared before and after a forest fire interrupted a prescribed timber harvest experiment. The affect of lake water chemistry, watershed characteristics, and trophic ecology on the bioaccumulation and biomagnification of MeHg in littoral food webs was also examined. The study area covered 2 ecoregions, the Boreal Foothills and the Boreal Mixedwood. Two years after the fire, MeHg concentrations in 5 of 6 aquatic taxa did not differ between burned and reference drainage basins in the Swan Hills. These results were in agreement with previous studies. Biomagnification of MeHg was negatively correlated with lake water chlorophyll 'a' concentration. Ecoregional variation in water chemistry seemed to influence MeHg concentrations in aquatic biota, which eluded comparisons of MeHg bioaccumulation between burned and reference drainage basins. MeHg concentrations in biota were negatively correlated with lake water pH, as well as with total phosphorous and dominant cation concentrations, all of which were higher in Mixedwood than in Foothills lakes. It was concluded that in the short-term, fire may lower MeHg concentrations in aquatic biota in a nutrient-rich setting by inducing an increase in lake productivity that dilutes MeHg at the base of the food web. 42 refs., 5 tabs., 7 figs.

  10. Lake Cadagno

    DEFF Research Database (Denmark)

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    cycles. The chemocline lies at about 12 m depth, stabilized by density differences of salt-rich water supplied by sub-aquatic springs to the monimolimnion and of electrolyte-poor surface water feeding the mixolimnion. Steep sulphide and light gradients in the chemocline support the growth of a large...... in the chemocline. Small-celled PSB together with the sulfate-reducing bacterium Desulfocapsa thiozymogenes sp. form stable aggregates in the lake, which represent small microenvironments with an internal sulphur cycle. Eukaryotic primary producers in the anoxic zones are dominated by Cryptomonas phaseolus...

  11. Predictive Modelling of Heavy Metals in Urban Lakes

    OpenAIRE

    Lindström, Martin

    2000-01-01

    Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. Predictive models focus on the variabilities among lakes and processes controlling the major metal fluxes. Sediment and water data for this study were collected from ten small lakes in the ...

  12. A preliminary study on sedimentation rate in Tasek Bera Lake estimated using Pb-210 dating technique

    International Nuclear Information System (INIS)

    Wan Zakaria Wan Muhamad Tahir; Johari Abdul Latif; Juhari Mohd Yusof; Kamaruzaman Mamat; Gharibreza, M.R.

    2010-01-01

    Tasek Bera is the largest natural lake system (60 ha) in Malaysia located in southwest Pahang. The lake is a complex dendritic system consisting of extensive peat-swamp forests. The catchment was originally lowland dipterocarp forest, but this has nearly over the past four decades been largely replaced with oil palm and rubber plantations developed by the Federal Land Development Authority (FELDA). Besides the environmentally importance of Tasek Bera, it is seriously subjected to erosion, sedimentation and morphological changes. Knowledge and information of accurate sedimentation rate and its causes are of utmost importance for appropriate management of lakes and future planning. In the present study, environmental 210 Pb (natural) dating technique was applied to determine sedimentation rate and pattern as well as the chronology of sediment deposit in Tasek Bera Lake. Three undisturbed core samples from different locations at the main entry and exit points of river mouth and in open water within the lake were collected during a field sampling campaign in October 2009 and analyzed for 210 Pb using gamma spectrometry method. Undisturbed sediments are classified as organic soils to peat with clayey texture that composed of 93 % clay, 5 % silt, and 2 % very fine sand. Comparatively higher sedimentation rates in the entry (0.06-1.58 cm/ yr) and exit (0.05-1.55 cm/ yr) points of the main river mouth as compared to the lakes open water (0.02- 0.74 cm/ yr) were noticed. Reasons for the different pattern of sedimentation rates in this lake and conclusion are discussed in this paper. (author)

  13. Occurrence of Porodaedalea pini (Brot.: Fr. Murr. in pine forests of the lake district in south-western Turkey

    Directory of Open Access Journals (Sweden)

    A. Lehtijärvi

    2007-12-01

    Full Text Available The occurrence of basidiocarps of the white rot fungus Porodaedalea (Phellinus pini on Pinus nigra subsp. pallasiana and P. brutia was investigated in six stands, covering a total land area of some 650 hectares, in Isparta province of the Lake District in Turkey. The height above ground of the lowermost P. pini basidiocarp was measured on each trunk. Basidiocarps of P. pini were found on thirty-eight trees, 32 P. nigra subsp. pallasiana (84.2% of the total and six P. brutia (15.8%. The breast-height diameter of P. nigra individuals with P. pini ranged from 41 to 188 cm (average 77.7 cm and that of P. brutia with P. pini from 68 to 96 cm (average 76.4 cm. Basidiocarps were mostly found on the lower part of the trunks of old trees. In addition to pathological aspects, the ecological role of the fungus in old-growth pine forests is discussed in relation to nature conservancy and biodiversity.

  14. Eastern deciduous forest biome progress report, September 1, 1975--August 31, 1976

    International Nuclear Information System (INIS)

    Burgess, R.L.; Tarr, N.E.

    1978-09-01

    The report concentrates on the six projects as well as results from synthesis activities at the Lake George, Lake Wingra, and Oak Ridge sites. The centralized analysis and modeling component and the Eastern Decidious Forest Biome Information Center progress during the past year are also addressed. The project on belowground dynamics of ecosystems is investigating the allocation of phytosynthetic products into fixed or labile storage pools. Root sampling, radioactive tracer techniques, and biochemical analyses are leading to an understanding of complete tree physioogy requisite for interpreting forest growth in different environments. The Role of Consumers project has begun to document the regulatory role of heterotrophs in an array of ecosystem niches. Decomposition of woody substrates, studies of the contribution of canopy and litter arthropods to material processing, and the flow and remineralization of phosphorus in lake systems are leading to a comprehensive understanding of the role of consumer organisms in ecosystem function. The Microdynamics of Detritus project continues its investigations of carbon and nitrogen dynamics in freshwater lakes. Examination of potential pathways of detritus processing is illustrating the parts that physical and biological processes play in the breakdown of organic materials

  15. Equations for estimating stand establishment, release, and thinning costs in the Lake States.

    Science.gov (United States)

    Jeffrey T. Olson; Allen L. Lundgren; Dietmar Rose

    1978-01-01

    Equations for estimating project costs for certain silvicultural treatments in the Lake States have been developed from project records of public forests. Treatments include machine site preparation, hand planting, aerial spraying, prescribed burning, manual release, and thinning.

  16. pH sensitivity of Swedish forest streams related to catchment characteristics and geographical location - Implications for forest bioenergy harvest and ash return

    Science.gov (United States)

    Ågren, Anneli; Löfgren, Stefan

    2013-04-01

    Whole-tree harvesting acidifies forest soils more than conventional harvest of stems. There is concern that this excess acidification will also affect surface waters and counteract the well-documented recovery from acid deposition in streams and lakes. Here we present a first attempt to identify the landscape types within Sweden where the streams are most sensitive to acidification and potentially in need of protection from excessive biomass harvest or countermeasures such as ash application. Conservative estimates indicate that forest slash must be harvested from >30 ha to produce the amount of ash needed to restore 1 ha acidified surface water. This highlights the need for careful planning of where ash should be distributed. Streams with a high pH are well buffered by the bicarbonate system and not sensitive to a potential pH decline. Streams with a low pH are also well buffered by dissolved organic carbon and aluminum and are not likely affected by bioenergy harvest. However, streams in the intermediate pH range (5-6.2) are potentially sensitive to acidification from excess base cation removal due to whole-tree harvesting. In such streams a small change in acid neutralizing capacity (ANC) can change pH dramatically. The pH sensitivity of 218 streams in different regions (northern, central, southern, and southwest Sweden) was defined from stream water pH and related to catchment characteristics and stream water acid-base chemistry. At the national level, catchments with till soils and a large proportion of forested wetlands formed the most pH sensitive areas. Because of regional variability in acidification history, amount and distribution of quaternary deposits, vegetation cover, etc. pH sensitivity was determined by different landscape elements in different regions. For example, in northern Sweden streams draining forest mires were the most pH sensitive streams. The patchy spatial distribution of this landscape type, makes it difficult from an administrative

  17. Potential climate change impacts on temperate forest ecosystem processes

    Science.gov (United States)

    Peters, Emily B.; Wythers, Kirk R.; Zhang, Shuxia; Bradford, John B.; Reich, Peter B.

    2013-01-01

    Large changes in atmospheric CO2, temperature and precipitation are predicted by 2100, yet the long-term consequences for carbon, water, and nitrogen cycling in forests are poorly understood. We applied the PnET-CN ecosystem model to compare the long-term effects of changing climate and atmospheric CO2 on productivity, evapotranspiration, runoff, and net nitrogen mineralization in current Great Lakes forest types. We used two statistically downscaled climate projections, PCM B1 (warmer and wetter) and GFDL A1FI (hotter and drier), to represent two potential future climate and atmospheric CO2 scenarios. To separate the effects of climate and CO2, we ran PnET-CN including and excluding the CO2 routine. Our results suggest that, with rising CO2 and without changes in forest type, average regional productivity could increase from 67% to 142%, changes in evapotranspiration could range from –3% to +6%, runoff could increase from 2% to 22%, and net N mineralization could increase 10% to 12%. Ecosystem responses varied geographically and by forest type. Increased productivity was almost entirely driven by CO2 fertilization effects, rather than by temperature or precipitation (model runs holding CO2 constant showed stable or declining productivity). The relative importance of edaphic and climatic spatial drivers of productivity varied over time, suggesting that productivity in Great Lakes forests may switch from being temperature to water limited by the end of the century.

  18. Water quality impacts of forest fires

    Science.gov (United States)

    Tecle Aregai; Daniel Neary

    2015-01-01

    Forest fires have been serious menace, many times resulting in tremendous economic, cultural and ecological damage to many parts of the United States. One particular area that has been significantly affected is the water quality of streams and lakes in the water thirsty southwestern United States. This is because the surface water coming off burned areas has resulted...

  19. The Socio-hydrology of Bangalore's Lake System and implications for Urban Water Security

    Science.gov (United States)

    Srinivasan, V.; Roy, S.

    2017-12-01

    Bengaluru city has experienced unprecedented growth in recent decades. If the city is to sustain growth and claim its position as a "global" high-tech city, it must be able to secure sufficient water supply and also create a healthy livable environment. With the city's many lakes vanishing due to rapid urbanisation, depletion of groundwater as a result of overuse in the peri-urban areas, and lack of proper underground drainage system and sewage treatment plants, Bangalore is now grappling with issues of imminent water crisis, inequitable access to water supply, and public health hazards. In this context, the restoration of Bangalore's lakes has been promoted as a panacea for its flooding, water stress, and wastewater problems. It has been argued that lakes can store storm water and recycled wastewater and avoid the need for potentially destructive, expensive schemes that may destroy biodiversity rich aquatic ecosystems and forests. Bangalore's lakes are linked by the drainage channels to form a cascade; overflow from each lake flows to the next lake downstream. Yet, most efforts have tended to view the lakes in isolation. This study of the hydrology of Bangalore's lake system in its entirety simulates the lake system as a whole. The study explores approaches to management and theor impact on urban water security.

  20. Lake ecosystem response to rapid lateglacial climate changes in lake sediments from northern Poland

    Science.gov (United States)

    Słowiński, Michał; Zawiska, Izabela; Ott, Florian; Noryśkiewicz, Agnieszka M.; Apolinarska, Karina; Lutyńska, Monika; Michczyńska, Danuta J.; Brauer, Achim; Wulf, Sabine; Skubała, Piotr; Błaszkiewicz, Mirosław

    2013-04-01

    During the Late Glacial Period environment changes were triggered by climatic oscillations which in turn controlled processes like, for example, permafrost thawing, vegetation development and ground water circulation. These environmental changes are ideally recorded in lake sediments and thus can be reconstructed applying a multi-poxy approach. Here, we present the results from the Trzechowskie paleolake, located in the northern Polish lowlands (eastern part of the Pomeranian Lakeland). The site is situated on the outwash plain of the Wda River, which was formed during the Pomeranian phase of the Vistulian glaciation ca 16,000 14C yrs BP. The depression of the Trzechowskie lake basin formed after melting of a buried ice block during the Allerød (13903±170 cal yrs BP). We reconstructed environmental changes in the Trzechowskie paleolake and its catchment using biotic proxies (macrofossils, pollen, cladocera, diatoms, oribatidae mite) and geochemical proxies (δ18O, δ13C, loss-on-ignition (LOI), CaCO3 content). In addition, we carried out µ-XRF element core scanning. The chronology has been established by means of biostratigraphyAMS14C dating on plant macro remains, varve counting in laminated intervals and the late Allerød Laacher See Tephra isochrone. Our results showed that biogenic accumulation in the lake started during the Bølling. Development of coniferous forest during the Allerød with dominance of Pinus sylvestris lead to leaching of carbonates in the catchment due to low pH increasing the flux of Ca ions into the lake. In consequence calcite precipitating in the lake increased as evidences by increasing CaCO3 contents. Both biotic and physical proxies clearly reflect the rapid decrease in productivity at the onset of the Younger Dryas. We compare the data from the Trzechowskie paleolake with the Meerfelder Maar and Rehwiese lake records based on tephrochronological synchronization using the Laacher See Tephra. This study is a contribution to the

  1. The impact of fish predation and cyanobacteria on zooplankton size structure in 96 subtropical lakes.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available Zooplankton are relatively small in size in the subtropical regions. This characteristic has been attributed to intense predation pressure, high nutrient loading and cyanobacterial biomass. To provide further information on the effect of predation and cyanobacteria on zooplankton size structure, we analyzed data from 96 shallow aquaculture lakes along the Yangtze River. Contrary to former studies, both principal components analysis and multiple regression analysis showed that the mean zooplankton size was positively related to fish yield. The studied lakes were grouped into three types, namely, natural fishing lakes with low nutrient loading (Type1, planktivorous fish-dominated lakes (Type 2, and eutrophic lakes with high cyanobacterial biomass (Type 3. A marked difference in zooplankton size structure was found among these groups. The greatest mean zooplankton size was observed in Type 2 lakes, but zooplankton density was the lowest. Zooplankton abundance was highest in Type 3 lakes and increased with increasing cyanobacterial biomass. Zooplankton mean size was negatively correlated with cyanobacterial biomass. No obvious trends were found in Type 1 lakes. These results were reflected by the normalized biomass size spectrum, which showed a unimodal shape with a peak at medium sizes in Type 2 lakes and a peak at small sizes in Type 3 lakes. These results indicated a relative increase in medium-sized and small-sized species in Types 2 and 3 lakes, respectively. Our results suggested that fish predation might have a negative effect on zooplankton abundance but a positive effect on zooplankton size structure. High cyanobacterial biomass most likely caused a decline in the zooplankton size and encouraged the proliferation of small zooplankton. We suggest that both planktivorous fish and cyanobacteria have substantial effects on the shaping of zooplankton community, particularly in the lakes in the eastern plain along the Yangtze River where

  2. Multi-Elements in Waters and Sediments of Shallow Lakes: Relationships with Water, Sediment, and Watershed Characteristics.

    Science.gov (United States)

    Kissoon, La Toya T; Jacob, Donna L; Hanson, Mark A; Herwig, Brian R; Bowe, Shane E; Otte, Marinus L

    2015-06-01

    We measured concentrations of multiple elements, including rare earth elements, in waters and sediments of 38 shallow lakes of varying turbidity and macrophyte cover in the Prairie Parkland (PP) and Laurentian Mixed Forest (LMF) provinces of Minnesota. PP shallow lakes had higher element concentrations in waters and sediments compared to LMF sites. Redundancy analysis indicated that a combination of site- and watershed-scale features explained a large proportion of among-lake variability in element concentrations in lake water and sediments. Percent woodland cover in watersheds, turbidity, open water area, and macrophyte cover collectively explained 65.2 % of variation in element concentrations in lake waters. Sediment fraction smaller than 63 µm, percent woodland in watersheds, open water area, and sediment organic matter collectively explained 64.2 % of variation in element concentrations in lake sediments. In contrast to earlier work on shallow lakes, our results showed the extent to which multiple elements in shallow lake waters and sediments were influenced by a combination of variables including sediment characteristics, lake morphology, and percent land cover in watersheds. These results are informative because they help illustrate the extent of functional connectivity between shallow lakes and adjacent lands within these lake watersheds.

  3. Dynamics of Phosphorus export from small forested catchments in low mountain ranges in Germany

    Science.gov (United States)

    Julich, Stefan; Julich, Dorit; Benning, Raphael; Feger, Karl-Heinz

    2017-04-01

    Phosphorus (P) plays an important role in the nutrition of forest ecosystem. The transport of P in forest soils predominantly occurs along preferential water flow pathways bypassing large parts of the soil matrix. Therefore, rapid flow processes by preferential flow and/or during storm events may lead to significant P losses from forest soils. However only little knowledge about the dynamics, magnitude and driving processes of P exports into surface water exist. In this contribution, we present the results of two studies where two small forested catchments have been monitored for a period around 3 years. Both catchments are situated in low mountain ranges in Saxony (catchment size 21 ha) and Thuringia (catchment size 5 ha) representing medium P contents in the topsoil of 1142 mg kg-1 and 834 mg kg-1 respectively. During the regular sampling (monthly to weekly sampling frequency), the mean Total-P concentrations of 23 μg L-1(Thuringian Site) and 8 μg L-1(Saxonian Site) have been measured. However, during single storm events Total-P concentrations increased considerably with maximum concentrations of 134 μg L-1(Thuringian Site) and 203 μg L-1(Saxonian Site). Our findings indicate that during storm events, especially after longer dry periods, significant amounts of phosphorus can be exported from forest ecosystems. Comparison of discharge-concentration patterns of Total-P, Nitrogen and DOC, as well as dye tracer experiments, suggest that preferential flow along biopores and stone surfaces, and the interface between mineral soil and litter layer are main pathways of export from forests. For the site in Saxony we calculated mean annual export rates of 32.8 to 33.5 g ha-1 a-1 based on the weekly sampling with different load calculation methods (flow weighted methods up to linear regression models). If the events are included into the annual load calculation the mean annual export fluxes increase from 47.8 to 58.6 g ha-1 a-1 based on the different load calculation

  4. Soil respiration patterns in root gaps 27 years after small scale experimental disturbance in Pinus contorta forests

    Science.gov (United States)

    Baker, S.; Berryman, E.; Hawbaker, T. J.; Ewers, B. E.

    2015-12-01

    While much attention has been focused on large scale forest disturbances such as fire, harvesting, drought and insect attacks, small scale forest disturbances that create gaps in forest canopies and below ground root and mycorrhizal networks may accumulate to impact regional scale carbon budgets. In a lodgepole pine (Pinus contorta) forest near Fox Park, WY, clusters of 15 and 30 trees were removed in 1988 to assess the effect of tree gap disturbance on fine root density and nitrogen transformation. Twenty seven years later the gaps remain with limited regeneration present only in the center of the 30 tree plots, beyond the influence of roots from adjacent intact trees. Soil respiration was measured in the summer of 2015 to assess the influence of these disturbances on carbon cycling in Pinus contorta forests. Positions at the centers of experimental disturbances were found to have the lowest respiration rates (mean 2.45 μmol C/m2/s, standard error 0.17 C/m2/s), control plots in the undisturbed forest were highest (mean 4.15 μmol C/m2/s, standard error 0.63 C/m2/s), and positions near the margin of the disturbance were intermediate (mean 3.7 μmol C/m2/s, standard error 0.34 C/m2/s). Fine root densities, soil nitrogen, and microclimate changes were also measured and played an important role in respiration rates of disturbed plots. This demonstrates that a long-term effect on carbon cycling occurs when gaps are created in the canopy and root network of lodgepole forests.

  5. Abundance of small mammals in the Atlantic Forest (ASMAF): a data set for analyzing tropical community patterns.

    Science.gov (United States)

    Figueiredo, Marcos S L; Barros, Camila S; Delciellos, Ana C; Guerra, Edú B; Cordeiro-Estrela, Pedro; Kajin, Maja; Alvarez, Martin R; Asfora, Paulo H; Astúa, Diego; Bergallo, Helena G; Cerqueira, Rui; Geise, Lena; Gentile, Rosana; Grelle, Carlos Eduardo V; Iack-Ximenes, Gilson E; Oliveira, Leonardo C; Weksler, Marcelo; Vieira, Marcus V

    2017-11-01

    Local abundance results from the interaction between populational and environmental processes. The abundance of the species in a community is also one of the most basic descriptors of its structure. Despite its importance, information about species abundances is fragmentary, creating a knowledge gap about species abundances known as the Prestonian Shortfall. Here we present a comprehensive data set of small mammal abundance in the Atlantic Forest. Data were extracted from 114 published sources and from unpublished data collected by our research groups spanning from 1943 to 2017. The data set includes 1,902 records of at least 111 species in 155 localities, totaling 42,617 individuals represented. We selected studies that (1) were conducted in forested habitats of the Atlantic Forest, (2) had a minimum sampling effort of at least 500 trap-nights, and (3) contained species abundance data in detail. For each study, we recorded (1) latitude and longitude, (2) name of the locality, (3) employed sampling effort, (4) type of traps used, (5) study year, (6) country, and (7) species name with (8) its respective abundances. For every locality, we also obtained information regarding its (9) ecoregion, (10) predominant vegetation type, and (11) biogeographic subdivision. Whenever necessary, we also (12) updated the species names as new species were described and some genera suffered taxonomic revision since the publication. The localities are spread across the Atlantic Forest and most of the small mammal species known to occur in Atlantic Forest are present in the data set, making it representative of communities of the entire biome. This data set can be used to address various patterns in community ecology and geographical ecology, as the relation between local abundance and environmental suitability, hypothesis regarding local and regional factors on community structuring, species abundance distributions (SAD), functional and phylogenetic mechanisms on community assembling

  6. Automatic structure classification of small proteins using random forest

    Directory of Open Access Journals (Sweden)

    Hirst Jonathan D

    2010-07-01

    Full Text Available Abstract Background Random forest, an ensemble based supervised machine learning algorithm, is used to predict the SCOP structural classification for a target structure, based on the similarity of its structural descriptors to those of a template structure with an equal number of secondary structure elements (SSEs. An initial assessment of random forest is carried out for domains consisting of three SSEs. The usability of random forest in classifying larger domains is demonstrated by applying it to domains consisting of four, five and six SSEs. Results Random forest, trained on SCOP version 1.69, achieves a predictive accuracy of up to 94% on an independent and non-overlapping test set derived from SCOP version 1.73. For classification to the SCOP Class, Fold, Super-family or Family levels, the predictive quality of the model in terms of Matthew's correlation coefficient (MCC ranged from 0.61 to 0.83. As the number of constituent SSEs increases the MCC for classification to different structural levels decreases. Conclusions The utility of random forest in classifying domains from the place-holder classes of SCOP to the true Class, Fold, Super-family or Family levels is demonstrated. Issues such as introduction of a new structural level in SCOP and the merger of singleton levels can also be addressed using random forest. A real-world scenario is mimicked by predicting the classification for those protein structures from the PDB, which are yet to be assigned to the SCOP classification hierarchy.

  7. Comparison of groundwater quality from forested (Waimarino River), urban (Turangi), and natural wetland (South Taupo Wetlands) subcatchments at the southern end of Lake Taupo

    International Nuclear Information System (INIS)

    Rosen, M.R.; Reeves, R.R.; Eser, P.; Chague-Goff, C.; Coshell, L.

    1998-01-01

    Comparison of groundwater quality of three different land uses, (1) exotic pine plantation ready for harvest (Waimarino River Catchment), (2) an urban area characterised by a land treatment facility for sewage effluent from Turangi (Turangi oxidation ponds), and (3) a natural wetland (South Taupo Wetlands) demonstrates that groundwater quality in the southern region of the Lake Taupo catchment is controlled by both natural and human influences in the area. Comparative water quality issues can be summarised as follows. (1) Naturally high concentrations of reduced iron and manganese are present in all three study areas, with the highest concentrations found in the natural wetland area and around the Turangi land treatment facility. (2) Concentrations of sodium, chloride, potassium, and ammonium in the groundwater down-gradient of the Turangi oxidation ponds are elevated relative to the other two study areas. Stable isotopic signatures also show that the groundwater has been influenced by surface water from the oxidation ponds, mostly due to additional evaporation caused by the relatively long residence time of the water (125 days) in the oxidation ponds. Elevated concentrations of ammonium also occur in deep groundwater under the forest areas of the Waimarino River catchment. (3) The water at all three sites is generally unsuitable for drinking supplies due to naturally elevated concentrations of reduced iron and manganese in the groundwater and elevated concentrations of ammonium at many monitoring sites, particularly around the Turangi land treatment site and the Waimarino deep aquifer monitoring sites. Aeration followed by settling or filtration of the groundwater could significantly reduce the concentrations of iron and manganese. (4) Elevated concentrations of reduced iron and manganese are unlikely to affect the water quality of Lake Taupo as all reduced iron and manganese will be oxidised once the water reaches the lake and precipitate as oxyhydroxide minerals

  8. To Conserve or not to Conserve: A case study of Forest Valuation of Tinderet Natural Forest

    International Nuclear Information System (INIS)

    Lang'at, D.; Cheboieo, J.; Siko, R

    2007-01-01

    Tinderet natural forest is part of the extensive Mau complex and forms an important hydrological system for lake Victoria. Information on on economic values of most forests in Kenya are not available or scanty. This paper aims at estimating the total economic value of Tinderet forest. Surveys were conducted on 109 households sampled from three villages within five kilometers of the forest. Further information/data was to determine direct use values. Other indirect use values (carbon sequestration and soil conservation) were were estimated by use of secondary data where the data not available, benefit transfer method was adopted. It was established that, the annual direct use of value to forest adjacent households is about Ksh. 33 million. The indirect use value is estimated at Ksh. 270 million and this value accrues to global community and not restricted to Kenya. The opportunity cost of conserving the Tinderet natural forest is estimated at Ksh. 210 million and only about Ksh. 33 million per year accrue as direct use values to the whole community. The current benefit from forest is inadequate to offset the community cost of of leaving the forest in it's present state. Based on this analysis, the government and the local communities are subsidizing the retention of the forest and this subsidy is currently estimated at at Ksh. 67 million through lost opportunity in settlement and income. In order to promote positive attitudes of the community adjustment to the forest on sustainable use of the forest, consumptive use of the forest should be encouraged

  9. Development of small businesses in tourism in the Lake Skadar National Park

    Directory of Open Access Journals (Sweden)

    Đurašević Silvana

    2014-01-01

    Full Text Available The subject of paper is a study of the possibilities for the development of small businesses and enterprise in the region of the Lake Skadar National Park, with an emphasis on a marketable tourism product. In a time of transition such as this, progress in the economy and therefore in tourism is highly dependent on the creation of a range of tourism products that are attractive both to the major consumer segments and to the niche market. Their successful promotion is intended to secure economic growth and a higher standard of living for the local population. The basic methodological approach has been secondary research, based on existing bibliographical sources. Primary research has included field visits, surveys of the local population, interviews with relevant representatives of small businesses and of the National Park and analysis of the results collected. The findings point to a need for change in the economic structure in favour of the development of small business and enterprise and for their networking with the objective of creating competitive products, facilitating employment and securing access to the market. In order to breathe life into this as yet underdeveloped region, potential sources of financing need to be secured and greater initiative on the part of the national and local government is needed. The cluster model is also considered herein as a way of halting economic and social decline in the local population, especially in terms of connecting the more developed southern region with the undeveloped north. Since the discussion concerns business development in an area that is under a special protection regime - which requires continual monitoring of carrying capacities - a priority in future development must be the sustainability of the natural and economic system in this region.

  10. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  11. Lake water quality: Chapter 4 in A synthesis of aquatic science for management of Lakes Mead and Mohave

    Science.gov (United States)

    Tietjen, Todd; Holdren, G. Chris; Rosen, Michael R.; Veley, Ronald J.; Moran, Michael J.; Vanderford, Brett; Wong, Wai Hing; Drury, Douglas D.

    2012-01-01

    Given the importance of the availability and quality of water in Lake Mead, it has become one of the most intensely sampled and studied bodies of water in the United States. As a result, data are available from sampling stations across the lake (fig. 4-1 and see U.S. Geological Survey Automated Water-Quality Platforms) to provide information on past and current (2012) water-quality conditions and on invasive species that influence—and are affected by—water quality. Water quality in Lakes Mead and Mohave generally exceeds standards set by the State of Nevada to protect water supplies for public uses: drinking water, aquatic ecosystem health, recreation, or agricultural irrigation. In comparison to other reservoirs studied by the U.S. Environmental Protection Agency (USEPA) for a national lake assessment (U.S. Environmental Protection Agency, 2010), Lake Mead is well within the highest or ‘good’ category for recreation and aquatic health (see U.S. Environmental Protection Agency National Lakes Assessment and Lake Mead for more details). While a small part of the lake, particularly Las Vegas Bay, is locally influenced by runoff from urbanized tributaries such as Las Vegas Wash, contaminant loading in the lake as a whole is low compared to other reservoirs in the nation, which are influenced by runoff from more heavily urbanized watersheds (Rosen and Van Metre, 2010).

  12. A diatom record of recent environmental change in Lake Duluti, northern Tanzania

    DEFF Research Database (Denmark)

    Öberg, Helena; Andersen, Thorbjørn Joest; Westerberg, Lars-Ove

    2012-01-01

    Lake Duluti is a small, topographically closed crater lake located on the flanks of Mt Meru, northern Tanzania. Analyses of diatoms in three short sediment cores and four modern samples from Lake Duluti were used to infer past environmental changes. 210Pb and 137Cs activity profiles combined...

  13. Biotic diversity interfaces with urbanization in the Lake Tahoe basin

    Science.gov (United States)

    Patricia N. Manley; Dennis D. Murphy; Lori A. Campbell; Kirsten E. Heckmann; Susan Merideth; Sean A. Parks; Monte P. Sanford; Matthew D. Schlesinger

    2006-01-01

    In the Lake Tahoe Basin, the retention of native ecosystems within urban areas may greatly enhance the landscape’s ability to maintain biotic diversity. Our study of plant, invertebrate and vertebrate species showed that many native species were present in remnant forest stands in developed areas; however, their richness and abundance declined in association with...

  14. Evaporation variability of Nam Co Lake in the Tibetan Plateau and its role in recent rapid lake expansion

    Science.gov (United States)

    Ma, Ning; Szilagyi, Jozsef; Niu, Guo-Yue; Zhang, Yinsheng; Zhang, Teng; Wang, Binbin; Wu, Yanhong

    2016-06-01

    Previous studies have shown that the majority of the lakes in the Tibetan Plateau (TP) started to expand rapidly since the late 1990s. However, the causes are still not well known. For Nam Co, being a closed lake with no outflow, evaporation (EL) over the lake surface is the only way water may leave the lake. Therefore, quantifying EL is key for investigating the mechanism of lake expansion in the TP. EL can be quantified by Penman- and/or bulk-transfer-type models, requiring only net radiation, temperature, humidity and wind speed for inputs. However, interpolation of wind speed data may be laden with great uncertainty due to extremely sparse ground meteorological observations, the highly heterogeneous landscape and lake-land breeze effects. Here, evaporation of Nam Co Lake was investigated within the 1979-2012 period at a monthly time-scale using the complementary relationship lake evaporation (CRLE) model which does not require wind speed data. Validations by in-situ observations of E601B pan evaporation rates at the shore of Nam Co Lake as well as measured EL over an adjacent small lake using eddy covariance technique suggest that CRLE is capable of simulating EL well since it implicitly considers wind effects on evaporation via its vapor transfer coefficient. The multi-year average of annual evaporation of Nam Co Lake is 635 mm. From 1979 to 2012, annual evaporation of Nam Co Lake expressed a very slight decreasing trend. However, a more significant decrease in EL occurred during 1998-2008 at a rate of -12 mm yr-1. Based on water-level readings, this significant decrease in lake evaporation was found to be responsible for approximately 4% of the reported rapid water level increase and areal expansion of Nam Co Lake during the same period.

  15. Hydrography, Our hydrography consist of rivers, lakes streams and small bodies of water. It was complied using steriovision from 1998-2000 Orthophotography., Published in 2007, Johnson County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Hydrography dataset current as of 2007. Our hydrography consist of rivers, lakes streams and small bodies of water. It was complied using steriovision from 1998-2000...

  16. Forest owners' perceptions of ecotourism: Integrating community values and forest conservation.

    Science.gov (United States)

    Rodríguez-Piñeros, Sandra; Mayett-Moreno, Yesica

    2015-03-01

    The use of forest land for ecotourism has been well accepted due to its ability to provide income to local people and to conserve the forest. Preparing the forest with infrastructure to attract and educate visitors has been reported of importance. This study applied Q methodology in a small rural community of the State of Puebla, Mexico, to reveal forest owners' perceptions to build infrastructure in their forest as part of their ecotourism project. It also discloses forest owners' underlying motives to use their forest for ecotourism. Ecotourism is perceived as a complementary activity to farming that would allow women to be involved in community development. Low impact infrastructure is desired due to forest owners' perception to preserve the forest for the overall community well-being.

  17. Fifty years of eutrophication and lake restoration reflected in sedimentary carbon and nitrogen isotopes of a small, hardwater lake (south Germany

    Directory of Open Access Journals (Sweden)

    Emanuel Braig

    2013-04-01

    Full Text Available This study analyses the response of the carbon and nitrogen isotopic composition of sedimentary organic matter to rapid human-induced eutrophication and meromixis as well as subsequent restoration efforts [in-lake phosphorus (P-Precipitation, P-remediation of the well inflow and multiannual destratification] in a 46-yr sediment core sequence (1963-2009 from Fischkaltersee, a small hard-water lake (S-Germany. In addition, the sediment record was compared with detailed data on water column chemistry during almost (1977-2009 the recorded history of eutrophication and trophic recovery of the named lake. While the onset of eutrophication resulted in an abrupt positive excursion (+2.4‰, the overall reaction of δ13CSOM to ongoing eutrophication and meromixis as well as to permanent hypolimnion aeration and trophic recovery is a continous negative trend (-3.7‰ with the most depleted signatures (-38.8‰ present in the youngest part of the core. This negative trend was not influenced by multiannual hypolimnion aeration, which although oxygenating bottom waters (>2 mg O2 L–1, did not reverse the increasing anoxis in the sediment, as is indicated by an declining Mn/Fe ratio. Hence, we conclude that in Fischkaltersee δ13CSOM was controlled by photoautotrophic input only during an early phase in the eutrophication process. The signal of intensifying microbially mediated carbon cycling processes in the sediment, i.e. methanogenesis and methanotrophy, was superimposed on the primary productivity signal by crossing a certain TP threshold (approx. TP=0.04 mg L–1. Sedimentary δ15N values exhibit an overall increase (+3.4‰ in reaction to the eutrophication process, while trophic recovery produces a continous decrease in the signal (-2.7‰. Linear correlation of δ15N to nitrate utilisation in the epilimnion, however, is rather weak (R2=0.33. Comparison between sediment δ15N values and water column data reveals that two negative shifts in the

  18. The effect of lake water quality and wind turbines on Rhode Island property sales price

    Science.gov (United States)

    Gorelick, Susan Shim

    This dissertation uses the hedonic pricing model to study the impact of lake water quality and wind turbines on Rhode Island house sales prices. The first two manuscripts are on lake water quality and use RI house sales transactions from 1988--2012. The third studies wind turbines using RI house sales transactions from 2000--2013. The first study shows that good lake water quality increases lakefront property price premium. It also shows that environmental amenities, such as forests, substitute for lake amenity as the property's distance from the lake increases. The second lake water quality study incorporates time variables to examine how environmental amenity values change over time. The results show that property price premium associated with good lake water quality does not change as it is constant in proportion to housing prices with short term economic fluctuations. The third study shows that wind turbines have a negative and significant impact on housing prices. However, this is highly location specific and varies with neighborhood demographics. All three studies have policy implications which are discussed in detail in the manuscripts below.

  19. Streamwater fluxes of total mercury and methylmercury into and out of Lake Champlain

    International Nuclear Information System (INIS)

    Shanley, James B.; Chalmers, Ann T.

    2012-01-01

    From 2000 to 2004, we sampled for total mercury (THg) and methylmercury (MeHg) in inlet streams to Lake Champlain, targeting high flow periods to capture increases in THg and MeHg concentrations with increasing flow. We used these data to model stream THg and MeHg fluxes for Water Years 2001 through 2009. In this mountainous forested basin with a high watershed-to-lake area ratio of 18, fluvial export from the terrestrial watershed was the dominant source of Hg to the lake. Unfiltered THg and MeHg fluxes were dominated by the particulate fraction; about 40% of stream THg was in the filtered ( −2 yr −1 , or about 13% of atmospheric Hg wet and dry deposition to the basin. THg export from the lake represented only about 3% of atmospheric Hg input to the basin. - Highlights: ► We monitored total mercury and methylmercury in major tributaries to Lake Champlain. ► Mercury and methylmercury export was primarily as particulates during high flow. ► Only 13% of atmospheric total mercury input reached the lake via streams. ► Only 3% of atmospheric total mercury input reached the lake outlet. - Eighty-seven percent of total mercury deposition to the Lake Champlain basin is retained in the terrestrial basin; stream export of total and methylmercury to the lake is primarily in the particulate phase.

  20. Hydrologic and Isotopic Sensitivity of Alpine Lakes to Climate Change in the Medicine Bow Mountains, Wyoming

    Science.gov (United States)

    Liefert, D. T.; Shuman, B. N.; Mercer, J.; Parsekian, A.; Williams, D. G.

    2017-12-01

    Climate reconstructions show that global average temperatures were 0.5°C higher than today during the mid-Holocene, falling well within projections for increases in global average temperature presented in the latest Intergovernmental Panel on Climate Change report. Despite the consensus for the prediction of a warmer climate, however, it is unclear how snowmelt from high-elevation watersheds will be affected by such a change. Snowmelt contributes substantially to major rivers in the western United States, and much of the water flows through lakes in the highest-elevation watersheds. Our water balance models show that modern alpine lakes with seasonably unstable water levels can desiccate primarily through groundwater outflow, resulting in increased groundwater storage that likely sustains baseflow in mountain streams once snowmelt has subsided in late summer. However, contribution of freshwater from alpine lakes to streams may vary over time as changes in climate alters snowpack, rates of evaporation, and the abundance of snowmelt-fed lakes. As such, alpine lakes with seasonally unstable water levels today may have dried out entirely during the mid-Holocene warm period and may dry out in the future as temperatures increase. To investigate the response of alpine lakes to temperatures of the mid-Holocene, we collected 9 sediment cores from closed-basin alpine lakes in the Medicine Bow Mountains of southern Wyoming that lose most their volumes each summer. We use radiocarbon-dating of charcoal in basal sediments to determine lake formation age, abundance of conifer needles to infer relative forest cover, and a δ18O carbonate record to determine changes in the ratio of evaporation to precipitation in an alpine lake that existed throughout the Holocene. Warming likely changed watershed hydrology through a) decreased snowpack and earlier snowmelt, b) increased evaporation, and c) increased transpiration associated with expanded forest cover and longer growing seasons

  1. Fertilization in northern forests

    DEFF Research Database (Denmark)

    Hedwall, Per Ola; Gong, Peichen; Ingerslev, Morten

    2014-01-01

    resources into food, health and industrial products and energy. Fertilization in Sweden and Finland is currently practiced by extensive fertilization regimens where nitrogen fertilizers are applied once, or up to three times, during a rotation period, mainly in mature forest. This type of fertilization...... gives, in most cases, a small and transient effect on the environment as well as a high rate of return to the forest owner with low-economic risk. The increase in biomass production, however, is relatively small and consequently the impact on the processing industry and the bioeconomy is limited. More...... in combination with present management systems and, almost instantly, enhances forest productivity. There may, however, be both economic and environmental constraints to large-scale applications of fertilizers in forest. Here we review the literature concerning biomass production of forests under different...

  2. Spatiotemporal patterns of mercury accumulation in lake sediments of western North America

    Science.gov (United States)

    Drevnick, Paul; Cooke, Colin A.; Barraza, Daniella; Blais, Jules M.; Coale, Kenneth; Cumming, Brian F.; Curtis, Chris; Das, Biplob; Donahue, William F.; Eagles-Smith, Collin A.; Engstrom, Daniel R.; Fitzgerald, William F.; Furl, Chad V.; Gray, John R.; Hall, Roland I.; Jackson, Togwell A.; Laird, Kathleen R.; Lockhart, W. Lyle; Macdonald, Robie W.; Mast, M. Alisa; Mathieu, Callie; Muir, Derek C.G.; Outridge, Peter; Reinemann, Scott; Rothenberg, Sarah E.; Ruiz-Fernandex, Ana Carolina; St. Louis, V.L.; Sanders, Rhea; Sanei, Hamed; Skierszkan, Elliott; Van Metre, Peter C.; Veverica, Timothy; Wiklund, Johan A.; Wolfe, Brent B.

    2016-01-01

    For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of “legacy” mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

  3. Arcellacea (testate amoebae) as bio-indicators of road salt contamination in lakes.

    Science.gov (United States)

    Roe, Helen M; Patterson, R Timothy

    2014-08-01

    Winter deicing operations occur extensively in mid- to high-latitude metropolitan regions around the world and result in a significant reduction in road accidents. Deicing salts can, however, pose a major threat to water quality and aquatic organisms. In this paper, we examine the utility of Arcellacea (testate amoebae) for monitoring lakes that have become contaminated by winter deicing salts, particularly sodium chloride. We analysed 50 sediment samples and salt-related water property variables (chloride concentrations; conductivity) from 15 lakes in the Greater Toronto Area and adjacent areas of southern Ontario, Canada. The sampled lakes included lakes in proximity to major highways and suburban roads and control lakes in forested settings away from road influences. Samples from the most contaminated lakes, with chloride concentrations in excess of 400 mg/l and conductivities of >800 μS/cm, were dominated by species typically found in brackish and/or inhospitable lake environments and by lower faunal diversities (lowest Shannon diversity index values) than samples with lower readings. Q-R-mode cluster analysis and detrended correspondence analysis (DCA) resulted in the recognition of four assemblage groupings. These reflect varying levels of salt contamination in the study lakes, along with other local influences, including nutrient loading. The response to nutrients can, however, be isolated if the planktic eutrophic indicator species Cucurbitella tricuspis is removed from the counts. The findings show that the group has considerable potential for biomonitoring in salt-contaminated lakes, and their presence in lake sediment cores may provide significant insights into long-term benthic community health, which is integral for remedial efforts.

  4. Growth, biomass, and production of two small barbs (Barbus humilis and B. tanapelagius, Cyprinidae) and their role in the food web of Lake Tana (Ethiopia)

    NARCIS (Netherlands)

    Dejen, E.; Vijverberg, J.; Nagelkerke, L.A.J.; Sibbing, F.A.

    2009-01-01

    Growth, biomass and production of two small barbs (Barbus humilis and Barbus tanapelagius) and their role in the food web of Lake Tana were investigated. From length–frequency distribution of trawl monitoring surveys growth coefficient, F' values were estimated at 3.71–4.17 for B. humilis and

  5. Detection and Segmentation of Small Trees in the Forest-Tundra Ecotone Using Airborne Laser Scanning

    Directory of Open Access Journals (Sweden)

    Marius Hauglin

    2016-05-01

    Full Text Available Due to expected climate change and increased focus on forests as a potential carbon sink, it is of interest to map and monitor even marginal forests where trees exist close to their tolerance limits, such as small pioneer trees in the forest-tundra ecotone. Such small trees might indicate tree line migrations and expansion of the forests into treeless areas. Airborne laser scanning (ALS has been suggested and tested as a tool for this purpose and in the present study a novel procedure for identification and segmentation of small trees is proposed. The study was carried out in the Rollag municipality in southeastern Norway, where ALS data and field measurements of individual trees were acquired. The point density of the ALS data was eight points per m2, and the field tree heights ranged from 0.04 to 6.3 m, with a mean of 1.4 m. The proposed method is based on an allometric model relating field-measured tree height to crown diameter, and another model relating field-measured tree height to ALS-derived height. These models are calibrated with local field data. Using these simple models, every positive above-ground height derived from the ALS data can be related to a crown diameter, and by assuming a circular crown shape, this crown diameter can be extended to a crown segment. Applying this model to all ALS echoes with a positive above-ground height value yields an initial map of possible circular crown segments. The final crown segments were then derived by applying a set of simple rules to this initial “map” of segments. The resulting segments were validated by comparison with field-measured crown segments. Overall, 46% of the field-measured trees were successfully detected. The detection rate increased with tree size. For trees with height >3 m the detection rate was 80%. The relatively large detection errors were partly due to the inherent limitations in the ALS data; a substantial fraction of the smaller trees was hit by no or just a few

  6. Forest resources within the Lake States ceded territories 1980 - 2013

    Science.gov (United States)

    Cassandra M. Kurtz; W. Keith Moser; Mark H. Hansen; Dale D. Gormanson; Mark A. Hatfield; Paul A. Sowers; Michael J. Dockry; Marla R. Emery; Christopher W. Woodall; Brian F. Walters; Grant M. Domke; Jonathan Gilbert; Alexandra. Wrobel

    2015-01-01

    The Lake States ceded territories are the portions of northern Michigan, northeastern Minnesota, and northern Wisconsin that were ceded by tribes of the Ojibwe to the government of the United States of America in the treaties of 1836, 1837, 1842, and 1854. The tribes retain rights to hunt, fish, and gather in the 1837, 1842, and 1854 treaty areas. This report...

  7. The partitioning of mercury in the solids components of forest soils and flooded forest soils in a hydroelectric reservoir, Quebec

    International Nuclear Information System (INIS)

    Dmytriw, R.P.

    1993-11-01

    Upon inundation, the soils in a hydroelection reservoir are subjected to several years of physical, biological and chemical changes as the transition from a terrestrial to an aquatic ecosystem is achieved. Changes in Eh, pH and microbial activity are believed to alter the metal binding capacity of solid substrates (organic matter, reactive Fe and Mn oxides, and clay minerals) within the soil profile, leading to remobilization of mercury associated with these phases. Four cores were collected along a transect from an unflooded forest soil to a pre-impoundment lake bottom sediment in the La-Grande-2 reservoir and watershed. The samples were sequentially extracted to determine the distribution of mercury between three operationally defined solid compartments: organic carbon, reactive Fe and Mn oxides/hydroxides, and the solid clay residue. Results indicate that up to 80% of the mercury in the O-horizon in forest soils and flooded forest soils, and up to 85% of the mercury in the lake sediments is bound to NaOH extractable organic carbon fractions. In the B-horizon podzol where organic content is low, 40-60% of the total mercury was found to be associated with reactive Fe minerals. In contrast, the flooded soil contains very little reactive Fe at any depth and the associated mercury concentrations are low. It is proposed that, upon inundation, oxide minerals are reduced and Hg released to the pore waters where it is immediately bound to an available substrate. Analyses of the residues suggests that there is an enrichment of mercury in the residual fraction immediately above the B-horizon of a flooded soil while the sulfide mineralization appears to play a role in sequestering mercury in lake sediments. 14 refs., 22 figs., 3 tabs

  8. The environmental state of Lake Ladoga sediments, Russia

    International Nuclear Information System (INIS)

    Pellinen, J.; Ristola, T.; Kukkonen, J.; Leppaenen, M.; Hoof, P.L. van; Robbins, J.A.

    1994-01-01

    The authors collected sediments in the summer 1993 from Lake Ladoga for chemical analyses and toxicity tests to assess the state of the lake. The sediments were analyzed for heavy metals, fluorides, chlorinated hydrocarbons, polyaromatic hydrocarbons, and certain radionuclides related to the fallout from the Chernobyl accident. In general, the concentrations of toxic chemicals were low. Most chemicals were below the limit of detection. The range of the total concentration of 17 PCB congeners was from 6 to 30 ng/kg dw; the highest value was at the pulp and paper mill located in the northeastern shore of the lake (Pitkaeranta). The highest concentrations of Cr, Co, Ni, Cu, Zn, Pb were 10, 42, 46, 36, 188, and 143 μg/g dw, respectively. Arsene was not detected at all and Cd only at one out of 12 sites studied. The toxicological testing with larvae of a midge, Chironomus riparius, and Daphnia magna resulted in only slight effects which may in part be related to different physical characteristics of the sediments rather than to toxic effects. The highest mortality was 75% at the deepest part of the lake (close to Valamo Island) which was believed to be the least polluted. The highest heavy metal concentrations and slow development of the larvae were observed for the same site. In the south of the lake at the Volhov Bay which receives effluents from forest and aluminum industry, the mortality was 10--50%

  9. Connectedness of land use, nutrients, primary production, and fish assemblages in oxbow lakes

    Science.gov (United States)

    Miranda, Leandro E.; Andrews, Caroline S.; Kroger, Robert

    2013-01-01

    We explored the strength of connectedness among hierarchical system components associated with oxbow lakes in the alluvial valley of the Lower Mississippi River. Specifically, we examined the degree of canonical correlation between land use (agriculture and forests), lake morphometry (depth and size), nutrients (total nitrogen and total phosphorus), primary production (chlorophyll-a), and various fish assemblage descriptors. Watershed (p < 0.01) and riparian (p = 0.02) land use, and lake depth (p = 0.05) but not size (p = 0.28), were associated with nutrient concentrations. In turn, nutrients were associated with primary production (p < 0.01), and primary production was associated with sunfish (Centrarchidae) assemblages (p < 0.01) and fish biodiversity (p = 0.08), but not with those of other taxa and functional guilds. Multiple chemical and biological components of oxbow lake ecosystems are connected to landscape characteristics such as land use and lake depth. Therefore, a top-down hierarchical approach can be useful in developing management and conservation plans for oxbow lakes in a region impacted by widespread landscape changes due to agriculture.

  10. Soil organic matter composition and quality across fire severity gradients in coniferous and deciduous forests of the southern boreal region

    Science.gov (United States)

    Jessica R. Miesel; William C. Hockaday; Randy Kolka; Philip A. Townsend

    2015-01-01

    Recent patterns of prolonged regional drought in southern boreal forests of the Great Lakes region, USA, suggest that the ecological effects of disturbance by wildfire may become increasingly severe. Losses of forest soil organic matter (SOM) during fire can limit soil nutrient availability and forest regeneration. These processes are also influenced by the composition...

  11. History of human activity in last 800 years reconstructed from combined archive data and high-resolution analyses of varved lake sediments from Lake Czechowskie, Northern Poland

    Science.gov (United States)

    Słowiński, Michał; Tyszkowski, Sebastian; Ott, Florian; Obremska, Milena; Kaczmarek, Halina; Theuerkauf, Martin; Wulf, Sabine; Brauer, Achim

    2016-04-01

    The aim of the study was to reconstruct human and landscape development in the Tuchola Pinewoods (Northern Poland) during the last 800 years. We apply an approach that combines historic maps and documents with pollen data. Pollen data were obtained from varved lake sediments at a resolution of 5 years. The chronology of the sediment record is based on varve counting, AMS 14C dating, 137Cs activity concentration measurements and tephrochronology (Askja AD 1875). We applied the REVEALS model to translate pollen percentage data into regional plant abundances. The interpretation of the pollen record is furthermore based on pollen accumulation rate data. The pollen record and historic documents show similar trends in vegetation development. During the first phase (AD 1200-1412), the Lake Czechowskie area was still largely forested with Quercus, Carpinus and Pinus forests. Vegetation was more open during the second phase (AD 1412-1776), and reached maximum openness during the third phase (AD 1776-1905). Furthermore, intensified forest management led to a transformation from mixed to pine dominated forests during this period. Since the early 20th century, the forest cover increased again with dominance of the Scots pine in the stand. While pollen and historic data show similar trends, they differ substantially in the degree of openness during the four phases with pollen data commonly suggesting more open conditions. We discuss potential causes for this discrepancy, which include unsuitable parameters settings in REVEALS and unknown changes in forest structure. Using pollen accumulation data as a third proxy record we aim to identify the most probable causes. Finally, we discuss the observed vegetation change in relation the socio-economic development of the area. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analysis - ICLEA- of the Helmholtz Association and National Science Centre, Poland (grant No. 2011/01/B/ST10

  12. Nonlinear vegetation cover changes in the North Ethiopian Highlands: Evidence from the Lake Ashenge closed basin

    Energy Technology Data Exchange (ETDEWEB)

    Lanckriet, Sil, E-mail: sil.lanckriet@ugent.be [Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium); Rucina, Stephen [National Museum of Kenya, Earth Science Department, Palynology Section, P.O. Box 40658 00100, Nairobi (Kenya); Frankl, Amaury [Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium); Ritler, Alfons [Centre for Development and Environment, University of Bern, Hallerstrasse 10, CH-3012 Bern (Switzerland); Gelorini, Vanessa [Department of Geology and Soil Science, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium); Nyssen, Jan [Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium)

    2015-12-01

    Vegetation cover changes in African drylands are often thought to result from population growth, social factors and aridification. Here we show that long-term vegetation proxy records can help disentangling these main driving factors. Taking the case of North Ethiopia, we performed an integrated investigation of land cover changes over the last four centuries around the endorheic Lake Ashenge, as derived from pollen analysis and repeat photography complemented with information from historical sources. Pollen and sediment analysis of radiocarbon-dated lake deposits shows a phase of environmental destabilization during the 18th century, after a more stable previous period. This is evidenced by decreases of tree pollen (Juniperus, Olea, Celtis, Podocarpus < 5%), increases in Poaceae (> 40%) and deposition of coarser silt lake sediments (> 70%). Quantitative analysis of 30 repeated landscape photographs around the lake indicates a gradual decline of the vegetation cover since a relative maximum during the mid-19th Century. Vegetation cover declined sharply between the 1950s and the 1980s, but has since begun to recover. Overall, the data from around Lake Ashenge reveal a nonlinear pattern of deforestation and forest regrowth with several periods of vegetation cover change over the past four centuries. While there is forcing of regional drought and the regional land tenure system, the cyclic changes do not support a simplified focus on aridification or population growth. - Highlights: • Vegetation cover changes are often related with population growth or climate • We investigated land cover changes over the last four centuries near Lake Ashenge • Overall, the data reveal a nonlinear pattern of deforestation and forest regrowth.

  13. Nonlinear vegetation cover changes in the North Ethiopian Highlands: Evidence from the Lake Ashenge closed basin

    International Nuclear Information System (INIS)

    Lanckriet, Sil; Rucina, Stephen; Frankl, Amaury; Ritler, Alfons; Gelorini, Vanessa; Nyssen, Jan

    2015-01-01

    Vegetation cover changes in African drylands are often thought to result from population growth, social factors and aridification. Here we show that long-term vegetation proxy records can help disentangling these main driving factors. Taking the case of North Ethiopia, we performed an integrated investigation of land cover changes over the last four centuries around the endorheic Lake Ashenge, as derived from pollen analysis and repeat photography complemented with information from historical sources. Pollen and sediment analysis of radiocarbon-dated lake deposits shows a phase of environmental destabilization during the 18th century, after a more stable previous period. This is evidenced by decreases of tree pollen (Juniperus, Olea, Celtis, Podocarpus < 5%), increases in Poaceae (> 40%) and deposition of coarser silt lake sediments (> 70%). Quantitative analysis of 30 repeated landscape photographs around the lake indicates a gradual decline of the vegetation cover since a relative maximum during the mid-19th Century. Vegetation cover declined sharply between the 1950s and the 1980s, but has since begun to recover. Overall, the data from around Lake Ashenge reveal a nonlinear pattern of deforestation and forest regrowth with several periods of vegetation cover change over the past four centuries. While there is forcing of regional drought and the regional land tenure system, the cyclic changes do not support a simplified focus on aridification or population growth. - Highlights: • Vegetation cover changes are often related with population growth or climate • We investigated land cover changes over the last four centuries near Lake Ashenge • Overall, the data reveal a nonlinear pattern of deforestation and forest regrowth

  14. Forests in catchment areas with special reference to the MUDA and Ahning dams: their roles in biodiversity conservation

    International Nuclear Information System (INIS)

    Mashhor Mansor

    2002-01-01

    During the field surveys conducted at the Muda and Ahning catchment areas, several rare and endemic plant species were recorded. The presence of relatively high population of Lagerstroemia speciosa in Muda is one of the conspicuous features of the forest in this catchment area. Unlike the Muda lake, a blue green algal bloom Oscillatoria kawamurde was observed at some parts of the Ahning lake particularly at the water surface. These catchment areas not only act as a buffer zone in the overall forest hydrological cycle but also play important roles in protecting and harbouring various species of plants and animals. (Author)

  15. Effects of liming and ash recycling on the outflow of mercury from forest soils - a theoretical study; Inverkan av kalkning och askaaterfoering paa utfloedet av kvicksilver fraan skogsmark - en teoretisk studie

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Arne; Nilsson, Ingvar [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences

    1994-12-31

    In this report, a theoretical review is made of the probable effects that spreading of lime and woodash in forests will have on the turnover of mercury in soil and on the outflow of mercury into water systems. As a result of historic emissions of mercury into the atmosphere, a large proportion of Swedish forest land has significantly increased concentrations of mercury, which is gradually leaching into lakes and watercourses. If an increased application of lime or woodash to forest soils were to result in a major change in the outflow of mercury, it could in time have a considerable effect on the mercury concentrations in lake fish. The fish in a large number of lakes in the southern part of Sweden already have mercury concentrations which are so high as to make them unsuitable for use as food. In conclusion, the theoretical assessment indicates in general that any effects on the mercury situation in lakes as a result of liming or woodash treatment of forest land are marginal or towards the positive side. It is not likely that these treatments increases the outflow of organic matter from soil. Any worsening of the mercury situation in lakes and watercourses will therefore hardly be the result of soil changes, but rather of processes in lakes and streams. Most of the evidence, however suggests that liming/ash treatment has predominantly positive effects with regard to the lake processes that control mercury levels in fish. At this juncture, available experience indicates that the mercury situation in the environment is in no way a decisive factor in determining where and how lime or ash should be applied to forest land. 64 refs, 2 figs

  16. Growth, biomass, and production of two small barbs (Barbus humilis and B. tanapelagius, Cyprinidae) and their role in the food web of Lake Tana (Ethiopia)

    NARCIS (Netherlands)

    Dejen, E.; Vijverberg, J.; Nagelkerke, L.A.J.; Sibbing, F.A.

    2009-01-01

    Growth, biomass and production of two small barbs (Barbus humilis and Barbus tanapelagius) and their role in the food web of Lake Tana were investigated. From length–frequency distribution of trawl monitoring surveys growth coefficient, Φ′ values were estimated at 3.71–4.17 for B. humilis and

  17. Working with Farmers to Reduce Phosphorus in Lake Champlain

    Science.gov (United States)

    EPA researchers are working with Vermont small dairy farmers to explore whether pasture-based rotational grazing can be a viable, cost-effective, option for small farms to help to reduce phosphorus loadings to the lake.

  18. Photochemical Reactivity of Dissolved Organic Matter in Boreal Lakes

    Science.gov (United States)

    Gu, Y.; Vuorio, K.; Tiirola, M.; Perämäki, S.; Vahatalo, A.

    2016-12-01

    Boreal lakes are rich in dissolved organic matter (DOM) that terrestrially derived from forest soil and wetland, yet little is known about potential for photochemical transformation of aquatic DOM in boreal lakes. Transformation of chromophoric dissolved organic matter (CDOM) can decrease water color and enhance microbial mineralization, affecting primary production and respiration, which both affect the CO2 balance of the lakes. We used laboratory solar radiation exposure experiments with lake water samples collected from 54 lakes located in Finland and Sweden, representing different catchment composition and watershed location to assess photochemical reactivity of DOM. The pH of water samples ranged from 5.4 to 8.3, and the concentrations of dissolved iron (Fe) were between samples received simulated solar radiation corresponding to a daily dose of sunlight, and photomineralization of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) was measured for determination of spectral apparent quantum yields (AQY). During irradiation, photobleaching decreased the absorption coefficients of CDOM at 330 nm between 4.9 and 79 m-1 by 0.5 to 11 m-1. Irradiation generated DIC from 2.8 to 79 μmol C L-1. The AQY at 330 nm ranged between 31 and 273 ×10-6 mol C mol photons-1 h-1, which was correlated positively with concentration of dissolved Fe, and negatively with pH. Further statistical analyze indicated that the interaction between pH and Fe may explain much of the photochemical reactivity of DOM in the examined lakes, and land cover concerns main catchment areas also can have impact on the photoreaction process. This study may suggest how environmental conditions regulate DOM photomineralization in boreal lakes.

  19. Land fauna composition of small mammals of a fragment of Atlantic Forest in the State of Sao Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Darci Moraes Barros-Battesti

    2000-03-01

    Full Text Available The Atlantic Forest small mammal land fauna, except bats, and the abiotic factors that might have an influence on its composition, were studied in the Itapevi County, State of Sao Paulo, a forested region, partly altered by antropic action, from January, 1995 to June, 1996. The trapping effort consisted of 2,888 trap-nights, resulting in a 4.6% trapping success and consisted of monthly trappings, for five consecutive days. During this period, 134 specimens were captured, of which 46.3% were Didelphimorphia and 53.7% were Rodentia. Eleven species were registered: two Didelphimorphia: Didelphis marsupialis (Linnaeus, 1758 and Marmosops incanus (Lund, 1841, and nine Rodentia: Akodon cursor (Winge, 1887, Bolomys lasiurus (Lund, 1841, Oxymycterus hispidus Pictet, 1843, Oxymycterus nasutus (Waterhouse, 1837, Oligoryzomys nigripes (Olfers, 1818, Oryzomys angouya (Fischer, 1814, Raltus norvegicus (Berkenhout, 1769, Euryzygomatomys spinosus (G. Fischer, 1814 and Cavia aperea Erxleben, 1777. The relative density indices were correlated with meteorological data by Spearman and Pearson coefficients. For marsupials these correlations were not significant. For rodents, the correlations were significant and directly related to lower temperature and rainfall indices (p<0.05. During the dry season the occurrence of small mammals was 50% greater than during the wet season, probably due to foraging strategies in the studied fragment of Atlantic Forest.

  20. The comparative limnology of Lakes Nyos and Monoun, Cameroon

    Science.gov (United States)

    Kling, George; Evans, William C; Tanyileke, Gregory

    2015-01-01

    Lakes Nyos and Monoun are known for the dangerous accumulation of CO2 dissolved in stagnant bottom water, but the shallow waters that conceal this hazard are dilute and undergo seasonal changes similar to other deep crater lakes in the tropics. Here we discuss these changes with reference to climatic and water-column data collected at both lakes during the years following the gas release disasters in the mid-1980s. The small annual range in mean daily air temperatures leads to an equally small annual range of surface water temperatures (ΔT ~6–7 °C), reducing deep convective mixing of the water column. Weak mixing aids the establishment of meromixis, a requisite condition for the gradual buildup of CO2 in bottom waters and perhaps the unusual condition that most explains the rarity of such lakes. Within the mixolimnion, a seasonal thermocline forms each spring and shallow diel thermoclines may be sufficiently strong to isolate surface water and allow primary production to reduce PCO2 below 300 μatm, inducing a net influx of CO2 from the atmosphere. Surface water O2 and pH typically reach maxima at this time, with occasional O2 oversaturation. Mixing to the chemocline occurs in both lakes during the winter dry season, primarily due to low humidity and cool night time air temperature. An additional period of variable mixing, occasionally reaching the chemocline in Lake Monoun, occurs during the summer monsoon season in response to increased frequency of major storms. The mixolimnion encompassed the upper ~40–50 m of Lake Nyos and upper ~15–20 m of Lake Monoun prior to the installation of degassing pipes in 2001 and 2003, respectively. Degassing caused chemoclines to deepen rapidly. Piping of anoxic, high-TDS bottom water to the lake surface has had a complex effect on the mixolimnion. Algal growth stimulated by increased nutrients (N and P) initially stimulated photosynthesis and raised surface water O2 in Lake Nyos, but O2 removal through oxidation of iron

  1. Modeling Prairie Pothole Lakes: Linking Satellite Observation and Calibration (Invited)

    Science.gov (United States)

    Schwartz, F. W.; Liu, G.; Zhang, B.; Yu, Z.

    2009-12-01

    behavior of a complex of closed lakes vary in scale from the footprint of a small house to that of a small city.

  2. THE SOMEŞAN PLATEAU LAKES: GENESIS, EVOLUTION AND TERRITORIAL REPARTITION

    Directory of Open Access Journals (Sweden)

    Victor SOROCOVSCHI

    2010-06-01

    Full Text Available The present paper analyzes the genesis of the lake depressions in the Someşan Plateau and the way they evolved in time and space, as well as the morphometric elements characteristic of the different genetic types of lakes. The natural lakes in this region are few and their dimensions are small; they generally appear solitarily and only rarely as lake complexes. In this category have been included the valley lakes, the lakes formed in abandoned meanders and the lakes formed in areas with landslides. The artificial lakes are more numerous and include several genetic types. The most representative are the remnant lakes formed in the depressions resulted from the exploitation of different construction materials (kaolin sands, lime stones and the anthropic salty lakes lakes formed in abandoned salt mines from the diapir area of the Hills of Dej. The rapid evolution of these types of lakes has been highlighted through the comparative analysis of the morphometric elements obtained on the basis of topometric and bathymetric measurements. The lakes arranged for pisciculture include several subtypes (ponds, fish ponds that have been identified and characterized for the fist time, their morphometric elements being determined using digital data bases, satellite images and detailed topometric maps.

  3. Rapid changes in the level of Kluane Lake in Yukon Territory over the last millennium

    Science.gov (United States)

    Clague, John J.; Luckman, Brian H.; Van Dorp, Richard D.; Gilbert, Robert; Froese, Duane; Jensen, Britta J. L.; Reyes, Alberto V.

    2006-09-01

    The level of Kluane Lake, the largest lake in Yukon Territory, was lower than at present during most of the Holocene. The lake rose rapidly in the late seventeenth century to a level 12 m above present, drowning forest and stranding driftwood on a conspicuous high-stand beach, remnants of which are preserved at the south end of the lake. Kluane Lake fell back to near its present level by the end of the eighteenth century and has fluctuated within a range of about 3 m over the last 50 yr. The primary control on historic fluctuations in lake level is the discharge of Slims River, the largest source of water to the lake. We use tree ring and radiocarbon ages, stratigraphy and sub-bottom acoustic data to evaluate two explanations for the dramatic changes in the level of Kluane Lake. Our data support the hypothesis of Hugh Bostock, who suggested in 1969 that the maximum Little Ice Age advance of Kaskawulsh Glacier deposited large amounts of sediment in the Slims River valley and established the present course of Slims River into Kluane Lake. Bostock argued that these events caused the lake to rise and eventually overflow to the north. The overflowing waters incised the Duke River fan at the north end of Kluane Lake and lowered the lake to its present level. This study highlights the potentially dramatic impacts of climate change on regional hydrology during the Little Ice Age in glacierised mountains.

  4. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    Science.gov (United States)

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Decadal oscillation of lakes and aquifers in the upper Great Lakes region of North America: hydroclimatic implications

    Science.gov (United States)

    Watras, C.J.; Read, J.S.; Holman, K.D.; Liu, Z.; Song, Y.-Y.; Watras, A.J.; Morgan, S.; Stanley, E.H.

    2014-01-01

    We report a unique hydrologic time-series which indicates that water levels in lakes and aquifers across the upper Great Lakes region of North America have been dominated by a climatically-driven, near-decadal oscillation for at least 70 years. The historical oscillation (~13y) is remarkably consistent among small seepage lakes, groundwater tables and the two largest Laurentian Great Lakes despite substantial differences in hydrology. Hydrologic analyses indicate that the oscillation has been governed primarily by changes in the net atmospheric flux of water (P-E) and stage-dependent outflow. The oscillation is hypothetically connected to large-scale atmospheric circulation patterns originating in the mid-latitude North Pacific that support the flux of moisture into the region from the Gulf of Mexico. Recent data indicate an apparent change in the historical oscillation characterized by a ~12y downward trend beginning in 1998. Record low water levels region-wide may mark the onset of a new hydroclimatic regime.

  6. Invasive floating macrophytes reduce greenhouse gas emissions from a small tropical lake.

    Science.gov (United States)

    Attermeyer, K; Flury, S; Jayakumar, R; Fiener, P; Steger, K; Arya, V; Wilken, F; van Geldern, R; Premke, K

    2016-02-05

    Floating macrophytes, including water hyacinth (Eichhornia crassipes), are dominant invasive organisms in tropical aquatic systems, and they may play an important role in modifying the gas exchange between water and the atmosphere. However, these systems are underrepresented in global datasets of greenhouse gas (GHG) emissions. This study investigated the carbon (C) turnover and GHG emissions from a small (0.6 km(2)) water-harvesting lake in South India and analysed the effect of floating macrophytes on these emissions. We measured carbon dioxide (CO2) and methane (CH4) emissions with gas chambers in the field as well as water C mineralization rates and physicochemical variables in both the open water and in water within stands of water hyacinths. The CO2 and CH4 emissions from areas covered by water hyacinths were reduced by 57% compared with that of open water. However, the C mineralization rates were not significantly different in the water between the two areas. We conclude that the increased invasion of water hyacinths and other floating macrophytes has the potential to change GHG emissions, a process that might be relevant in regional C budgets.

  7. Invasive floating macrophytes reduce greenhouse gas emissions from a small tropical lake

    Science.gov (United States)

    Attermeyer, K.; Flury, S.; Jayakumar, R.; Fiener, P.; Steger, K.; Arya, V.; Wilken, F.; van Geldern, R.; Premke, K.

    2016-02-01

    Floating macrophytes, including water hyacinth (Eichhornia crassipes), are dominant invasive organisms in tropical aquatic systems, and they may play an important role in modifying the gas exchange between water and the atmosphere. However, these systems are underrepresented in global datasets of greenhouse gas (GHG) emissions. This study investigated the carbon (C) turnover and GHG emissions from a small (0.6 km2) water-harvesting lake in South India and analysed the effect of floating macrophytes on these emissions. We measured carbon dioxide (CO2) and methane (CH4) emissions with gas chambers in the field as well as water C mineralization rates and physicochemical variables in both the open water and in water within stands of water hyacinths. The CO2 and CH4 emissions from areas covered by water hyacinths were reduced by 57% compared with that of open water. However, the C mineralization rates were not significantly different in the water between the two areas. We conclude that the increased invasion of water hyacinths and other floating macrophytes has the potential to change GHG emissions, a process that might be relevant in regional C budgets.

  8. Characteristics and ontogeny of oligotrophic hardwater lakes in the Forsmark area, central Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Brunberg, A.K.; Blomqvist, P. [Uppsala Univ. (Sweden). Dept. of Limnology

    1999-12-01

    This is the first part of a report characterising the lakes of Uppsala county, with special emphasis on the coastal lakes in the Forsmark area.The aim of the study is to characterise different main types of lakes within the Forsmark area and to create a basis for prediction of their ontogeny, that can be used also for new lakes which due to shoreline displacement will be formed during the next 10 000 years. Areas where future research is needed to fully understand the functioning of the lake ecosystems and their ontogeny should also be identified. This first part of the study identifies and describes one of the most common lake types in the area, the oligotrophic hardwater lake. The geology in the catchments of the Forsmark area includes a bedrock dominated by granites and gneisses, covered by calcareous glacial till and postglacial clay. The catchments are dominated by forest, and the oligotrophic hardwater lakes are to a large extent surrounded by mires. Inflow as well as outflow of water is often diffuse, via the surrounding mire. The lakes are small and shallow, with nutrient poor and highly alkaline water. Three key habitats have been identified within the lakes; the pelagic zone, characterised by low production of biota;, the presumably moderately productive emergent macrophyte zone, dominated by Sphagnum and Phragmites;, and the light exposed soft-bottom zone with Chara meadows and an unusually rich and presumably highly productive microbial sediment community. The oligotrophic hardwater lakes have their origin as depressions in the bottom of the Baltic Sea, which are successively transported upwards due to the land-rise process in the area. As the basins are isolated from the sea , a gradual change from a brackish to freshwater conditions occur. When the lakes have become completely isolated, the oligotrophic hardwater stage follows, due to inflow of carbonate-rich and well buffered groundwater. In the next successional stage, Sphagnum mosses start to

  9. Characteristics and ontogeny of oligotrophic hardwater lakes in the Forsmark area, central Sweden

    International Nuclear Information System (INIS)

    Brunberg, A.K.; Blomqvist, P.

    1999-12-01

    This is the first part of a report characterising the lakes of Uppsala county, with special emphasis on the coastal lakes in the Forsmark area.The aim of the study is to characterise different main types of lakes within the Forsmark area and to create a basis for prediction of their ontogeny, that can be used also for new lakes which due to shoreline displacement will be formed during the next 10 000 years. Areas where future research is needed to fully understand the functioning of the lake ecosystems and their ontogeny should also be identified. This first part of the study identifies and describes one of the most common lake types in the area, the oligotrophic hardwater lake. The geology in the catchments of the Forsmark area includes a bedrock dominated by granites and gneisses, covered by calcareous glacial till and postglacial clay. The catchments are dominated by forest, and the oligotrophic hardwater lakes are to a large extent surrounded by mires. Inflow as well as outflow of water is often diffuse, via the surrounding mire. The lakes are small and shallow, with nutrient poor and highly alkaline water. Three key habitats have been identified within the lakes; the pelagic zone, characterised by low production of biota;, the presumably moderately productive emergent macrophyte zone, dominated by Sphagnum and Phragmites;, and the light exposed soft-bottom zone with Chara meadows and an unusually rich and presumably highly productive microbial sediment community. The oligotrophic hardwater lakes have their origin as depressions in the bottom of the Baltic Sea, which are successively transported upwards due to the land-rise process in the area. As the basins are isolated from the sea , a gradual change from a brackish to freshwater conditions occur. When the lakes have become completely isolated, the oligotrophic hardwater stage follows, due to inflow of carbonate-rich and well buffered groundwater. In the next successional stage, Sphagnum mosses start to

  10. Hydrochemical patterns of a small lake and a stream in an uplifting area proposed as a repository site for spent nuclear fuel, Forsmark, Sweden

    Science.gov (United States)

    Rönnback, Pernilla; Åström, Mats

    2007-10-01

    SummaryThe overall aim of this study was to increase the understanding of the chemical dynamics of small catchments. The focus was on a small oligotropic lake and its major inflow stream in an uplifting area in eastern Sweden (Forsmark) proposed as a repository site for spent nuclear fuel. The hydrochemical sampling campaign lasted for nearly 4 years with sample collection monthly to semi-monthly, and continuous flow measurements carried out over the last 20 months. All this was done as part of the Swedish Nuclear Fuel and Waste Management Company's (SKBs) Site Investigation Programme. The major findings were: (1) as a result of the calcareous overburden caused by redistributed Paleozoic deposits, pH and the Ca and HCO3- concentrations were relatively high in both the stream and lake throughout the period, (2) limnic primary production resulted in decreased concentrations of Ca, HCO3-, NH4+, NO3- and Si, and increased pH and concentrations of chlorophyll a, O 2, DON, POC, PON and POP in the lake in summer, while in other seasons (in winter in particular) when the production was minimal or non-existent the concentrations in the lake and the inflow stream were similar, (3) intrusion of brackish-water resulted in moderately to strongly increased concentrations of Cl -, Na, Mg, Br -, SO42-, K and Sr in the lake: the ratio versus Cl - were for Na and Br - always similar to those in sea water, for Mg and SO42- similar to those in sea water at elevated Cl - concentrations (>3 mM), while K and Sr always occurred in relative excess as compared to sea water, (4) high U concentrations in both the stream and the lake was derived most likely from reduced U-minerals in the overburden and was predicted to be carried to >90% in the form of calcium uranyl carbonate, in a model in which colloidal Fe and Al oxyhydroxides were not considered, (5) the rare earth elements (REEs) had similar concentrations and fractionation patterns in the stream and lake, unlike those found in the

  11. Driving forces of the diel distribution of phytoplankton functional groups in a shallow tropical lake (Lake Monte Alegre, Southeast Brazil

    Directory of Open Access Journals (Sweden)

    LM. Rangel

    Full Text Available Phytoplankton vertical and diel dynamics in a small shallow lake (Lake Monte Alegre, Ribeirão Preto, state of São Paulo were investigated in two climatological periods: July 2001 (cool-dry season and March 2002 (warm-rainy season. Monte Alegre is a eutrophic reservoir, with a warm polymictic discontinuous circulation pattern. The lake was thermally stratified in both periods, although dissolved oxygen varied less in the cool-dry period. Phytoplankton biomass was higher in the warm-rainy season and the vertical distribution was stratified in both seasons. Flagellate groups (Lm, Y, W1 and W2 and functional groups typical of shallow eutrophic environments (J, X1 and Sn were important throughout the study period. The lake's thermal pattern strongly influenced the vertical distribution of the phytoplankton community in both periods. Biomass, functional groups and size classes of phytoplankton also were determined by the presence of more efficient herbivores in the lake, especially during the cool-dry period when phytoplankton biomass decreased.

  12. Carbon annuities and their potential to preserve tropical forests and slow global warming: an application for small-scale farmers

    Energy Technology Data Exchange (ETDEWEB)

    Caviglia-Harris, J.L. [Salisbury University, Salisbury, MD (United States). Dept. of Economics and Finance; Kahn, J.R. [Washington and Lee University, Lexington, VA (United States). Dept. of Economics

    2003-07-01

    Carbon annuities have been suggested as a means for rewarding landowners for preserving forests and sequestering carbon. Although this is an intuitively appealing approach, the benefits of the sequestration activities have not been compared with the opportunity cost of preserving the forest. This paper represents an initial attempt at analysing how large carbon annuities must be to induce a landowner in the Amazonian rainforest to accept the annuity and leave the forest intact. The benefits of carbon sequestration are computed based on estimates in the literature on the carbon contained in a hectare of rainforest and the damages associated with a ton of carbon emissions. This is compared with information on household income from Rondonia, Brazil. Our results show that, for the majority of our conservative assumptions about the damages of carbon emissions, the magnitude of an annuity is greater than the income from agriculture. For less conservative assumptions about the damages from global warming, a fraction of the annuity would be a sufficient incentive for small- scale farmers to switch to sustainable techniques that leave the forest intact. (author)

  13. Total mercury and methylmercury fluxes via emerging insects in recently flooded hydroelectric reservoirs and a natural lake

    International Nuclear Information System (INIS)

    Tremblay, Alain; Lucotte, Marc; Cloutier, Louise

    1998-01-01

    Total mercury (total Hg) concentrations in emerging aquatic insects ranged from 140 to 1500 ng g -1 dry wt. in two hydroelectric reservoirs of northern Quebec compared with 50-160 ng g -1 dry wt. in a natural lake. Methylmercury (MeHg) concentrations were somewhat lower, ranging from 35 to 800 ng Hg g -1 dry wt. in reservoirs and from 29 to 90 ng g -1 dry wt. in the natural lake. Contamination of insect taxa of reservoirs was on average 2-3 times higher than their counterparts in the natural lake. There was no difference between total Hg and MeHg concentrations of insects sampled from flooded forest soils and flooded peatland, although total Hg and MeHg concentrations differed between flooded peatland and flooded forest soils themselves. Insect biomasses were approx. two times higher in the reservoirs than in the natural lake (580-2200 mg m -2 year -1 dry wt., 950 mg m -2 year -1 dry wt., respectively); chironomids dominated in the reservoirs and trichopterans dominated in the natural lake. Similarly, total MeHg fluxes via emerging insects were approx. 2-4 times higher in reservoirs than that of the natural lake (55-224 ng MeHg m -2 year -1 dry wt., 74 ng MeHg m -2 year -1 dry wt., respectively). Our results show the importance of the insect community in the transfer of MeHg from flooded soils and flooded peatlands to fish, and that this pathway probably makes a significant contribution to the rapid rise of Hg levels in the fish community after flooding

  14. Composition and abundance of small mammal communities in forest fragments and vegetation corridors in Southern Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Andréa O. Mesquita

    2012-09-01

    Full Text Available Habitat fragmentation leads to isolation and reduce habitat areas, in addition to a series of negative effects on natural populations, affecting richness, abundance and distribution of animal species. In such a text, habitat corridors serve as an alternative for connectivity in fragmented landscapes, minimizing the effects of structural isolation of different habitat areas. This study evaluated the richness, composition and abundance of small mammal communities in forest fragments and in the relevant vegetation corridors that connect these fragments, located in Southern Minas Gerais, Southeastern Brazil. Ten sites were sampled (five forest fragments and five vegetation corridors using the capture-mark-recapture method, from April 2007-March 2008. A total sampling effort of 6 300 trapnights resulted in 656 captures of 249 individuals. Across the 10 sites sampled, 11 small mammal species were recorded. Multidimensional scaling (MDS ordinations and ANOSIM based on the composition of small mammal communities within the corridor and fragment revealed a qualitative difference between the two environments. Regarding abundance, there was no significant difference between corridors and fragments. In comparing mean values of abundance per species in each environment, only Cerradomys subflavus showed a significant difference, being more abundant in the corridor environment. Results suggest that the presence of several small mammal species in the corridor environment, in relatively high abundances, could indicate corridors use as habitat, though they might also facilitate and/or allow the movement of individuals using different habitat patches (fragments.

  15. Small scale endemism in Brazil's Atlantic Forest: 14 new species of Mesabolivar (Araneae, Pholcidae), each known from a single locality.

    Science.gov (United States)

    Huber, Bernhard A

    2015-04-07

    In an ongoing mega-transect project that aims at analyzing pholcid spider diversity and distribution in the Atlantic Forest of Brazil, many species appear restricted to small geographic ranges. Of the 84 species collected between 2003 and 2011 at 17 sites between Bahia and Santa Catarina, 51 species (61%) were found at only one locality. The present paper focuses on such species in the genus Mesabolivar, and compares diversity and distribution patterns of this genus within and outside the Atlantic Forest. The percentage of species known from single localities is higher in the Atlantic Forest (34 of 52 species; 65%) than outside the Atlantic Forest (10 of 25; 40%). Distribution rages of species in the Atlantic Forest are significantly smaller than of species outside the Atlantic Forest (mean maximum distances between localities: 184 versus 541 km; medians: 10 km versus 220 km). The following species are newly described (arranged from north to south), each currently known from the respective type locality only: M. caipora; M. kathrinae; M. bonita; M. pau (Bahia); M. monteverde; M. perezi (Espírito Santo); M. giupponii; M. goitaca; M. sai (Rio de Janeiro); M. tamoio; M. unicornis; M. gabettae; M. inornatus (São Paulo); M. itapoa (Santa Catarina).

  16. Local monitoring program for invasion of zebra mussel (Dreissena polymorpha) in the Dam lake Zhrebchevo, Bulgaria

    OpenAIRE

    Stoyanova, Stefka; Nikolov, Galin; Velichkova, Katya; Atanasoff, Alexander; Mumun, Sevdegul

    2015-01-01

    Zebra mussels (Dreissena polymorpha) are bivalve mollusks approximately 1 to 5 cm long that live in freshwater lakes. They have invaded many Bulgarian freshwater ecosystems in recent decades. Because of their ability to settle on almost any substrate, zebra mussels cause severe damage to closed water systems, RAS and intensive fish farming systems. In order to assess the status of the mussel population in the lake in the area of the Forest group fish farm, the distribution, extent of coloniza...

  17. Forests in the biogeographical corridors connecting the Fennoscandian shield and the Russian plain: natural features, contemporary status, environmental significance

    Directory of Open Access Journals (Sweden)

    A. N. Gromtsev

    2016-12-01

    Full Text Available The results of long-term research on forests in natural biogeographical corridors (territories with forests, mires, inland lakes and other land categories connecting the largest bodies of water in Northern Europe (Baltic Sea-Gulf of Finland and lakes Ladoga and Onego to the White Sea are reported. These corridors link isolated pieces of the Eurasian taiga biome at the boundary between two of Europe’s physiographic divisions – Fennoscandian Shield and Russian Plain. They facilitate the dispersal and migration of plant and animal species. The straight-line terrestrial stretch between the Gulf of Finland and the White Sea is around 320 km, and it falls into three sections in the southern, middle and northern taiga subzones, respectively. The corridors were characterized and assessed as follows: 1 physiographic (landscape features; 2 key natural characteristics (typological structure, quantitative ratios, spatial arrangement, productivity, etc., present-day condition of forests, including data from forest management inventories of the past decade; 3 overall assessment of the forest cover transformation by human impact; 4 current system of protected areas and protective forests, and its capacity to fulfill the functions of the corridors (sufficiency.

  18. Homogenization of northern U.S. Great Lakes forests due to land use

    Science.gov (United States)

    Lisa A. Schulte; David J. Mladenoff; Thomas R. Crow; Laura C. Merrick; David T. Cleland

    2007-01-01

    Human land use of forested regions has intensified worldwide in recent decades, threatening long-term sustainability. Primary effects include conversion of land cover or reversion to an earlier stage of successional development. Both types of change can have cascading effects through ecosystems; however, the longterm effects where forests are allowed to regrow are...

  19. Seasonality in the dung beetle community in a Brazilian tropical dry forest: Do small changes make a difference?

    Science.gov (United States)

    Medina, Anderson Matos; Lopes, Priscila Paixão

    2014-01-01

    Dung beetle (Coleoptera: Scarabaeoidea: Scarabaeinae) activity is influenced by rainfall seasonality. We hypothesized that rainfall might also play a major role in regulating the community structure of this group. In this study, we describe seasonal changes in the richness, composition, and structure of the Scarabaeinae community in a Brazilian tropical dry forest. A fragment of arboreal Caatinga was sampled using baited pitfall traps during the early dry season (EDS), late dry season (LDS), early wet season (EWS), and middle wet season (MWS). We compared the dung beetle community in each season in relationship to species richness, rank-dominance, curves, and composition. We collected 1352 Scarabaeinae individuals , belonging to 15 species. Dichotomius aff. laevicollis Felsche (Coleoptera: Scarabaeidae) was the dominant species, representing 73.89% of the individuals. There were no seasonal changes in the rank dominance curves; all had a single dominant species and a few species with low abundance, typical for arid areas. Estimated richness was highest in MWS, followed by EWS. Dry-season samples (EDS and LDS) had lower richness, with no significant difference between the dry seasons. Although species richness increased as the habitat became wetter, the difference between the wet and dry seasons was small, which differs completely from the findings of other studies in Neotropical dry forests, where almost all species cease activities in the dry season. Species composition changes were found in non-metric multidimensional scaling and sustained by analysis of similarity. All the seasons had pairwise differences in composition, with the exception of EDS and MWS, which indicates that the dung beetle community in this fragment requires more than three months of drought to trigger changes in species composition; this is probably due to small changes in the forest canopy. There was no difference in composition between EDS and MWS. As in other tropical dry forests, although

  20. Holocene climate on the Modoc Plateau, northern California, USA: The view from Medicine Lake

    Science.gov (United States)

    Starratt, Scott W.

    2009-01-01

    Medicine Lake is a small (165 ha), relatively shallow (average 7.3 m), intermediate elevation (2,036 m) lake located within the summit caldera of Medicine Lake volcano, Siskiyou County, California, USA. Sediment cores and high-resolution bathymetric and seismic reflection data were collected from the lake during the fall of 1999 and 2000. Sediments were analyzed for diatoms, pollen, density, grain size (sand/mud ratio), total organic carbon (TOC), and micro-scale fabric analysis. Using both 14C (AMS) dating and tephrochronology, the basal sediments were estimated to have been deposited about 11,400 cal year BP, thus yielding an estimated average sedimentation rate of about 20.66 cm/1,000 year. The lowermost part of the core (11,400–10,300 cal year BP) contains the transition from glacial to interglacial conditions. From about 11,000–5,500 cal year BP, Medicine Lake consisted of two small, steep-sided lakes or one lake with two steep-sided basins connected by a shallow shelf. During this time, both the pollen (Abies/Artemisia ratio) and the diatom (Cyclotella/Navicula ratio) evidences indicate that the effective moisture increased, leading to a deeper lake. Over the past 5,500 years, the pollen record shows that effective moisture continued to increase, and the diatom record indicates fluctuations in the lake level. The change in the lake level pattern from one of the increasing depths prior to about 6,000 cal year BP to one of the variable depths may be related to changes in the morphology of the Medicine Lake caldera associated with the movement of magma and the eruption of the Medicine Lake Glass Flow about 5,120 cal year BP. These changes in basin morphology caused Medicine Lake to flood the shallow shelf which surrounds the deeper part of the lake. During this period, the Cyclotella/Navicula ratio and the percent abundance of Isoetes vary, suggesting that the level of the lake fluctuated, resulting in changes in the shelf area

  1. A New Precision Measurement of the Small-scale Line-of-sight Power Spectrum of the Lyα Forest

    Science.gov (United States)

    Walther, Michael; Hennawi, Joseph F.; Hiss, Hector; Oñorbe, Jose; Lee, Khee-Gan; Rorai, Alberto; O’Meara, John

    2018-01-01

    We present a new measurement of the Lyα forest power spectrum at 1.8 masking missing data, damped Lyα absorption systems, and metal absorption lines. Our measurement results in unprecedented precision on the small-scale modes k> 0.02 {{s}} {{km}}-1, inaccessible to previous SDSS/BOSS analyses. It is well known that these high-k modes are highly sensitive to the thermal state of the intergalactic medium, but contamination by narrow metal lines is a significant concern. We quantify the effect of metals on the small-scale power and find a modest effect on modes with kmasking metals and restricting to kmasking as our data are generated from Lyα forest simulations. These mock spectra are used to build a custom emulator, enabling us to interpolate between a sparse grid of models and perform Markov chain Monte Carlo fits. Our results agree well with BOSS on scales kdata set for precisely constraining the thermal history of the intergalactic medium, cosmological parameters, and the nature of dark matter. The power spectra and their covariance matrices are provided as electronic tables.

  2. Modeling lakes and reservoirs in the climate system

    Science.gov (United States)

    MacKay, M.D.; Neale, P.J.; Arp, C.D.; De Senerpont Domis, L. N.; Fang, X.; Gal, G.; Jo, K.D.; Kirillin, G.; Lenters, J.D.; Litchman, E.; MacIntyre, S.; Marsh, P.; Melack, J.; Mooij, W.M.; Peeters, F.; Quesada, A.; Schladow, S.G.; Schmid, M.; Spence, C.; Stokes, S.L.

    2009-01-01

    Modeling studies examining the effect of lakes on regional and global climate, as well as studies on the influence of climate variability and change on aquatic ecosystems, are surveyed. Fully coupled atmosphere-land surface-lake climate models that could be used for both of these types of study simultaneously do not presently exist, though there are many applications that would benefit from such models. It is argued here that current understanding of physical and biogeochemical processes in freshwater systems is sufficient to begin to construct such models, and a path forward is proposed. The largest impediment to fully representing lakes in the climate system lies in the handling of lakes that are too small to be explicitly resolved by the climate model, and that make up the majority of the lake-covered area at the resolutions currently used by global and regional climate models. Ongoing development within the hydrological sciences community and continual improvements in model resolution should help ameliorate this issue.

  3. Historic carbon burial spike in an Amazon floodplain lake linked to riparian deforestation near Santarém, Brazil

    Science.gov (United States)

    Sanders, Luciana M.; Taffs, Kathryn; Stokes, Debra; Sanders, Christian J.; Enrich-Prast, Alex; Amora-Nogueira, Leonardo; Marotta, Humberto

    2018-01-01

    Forests along the Amazon Basin produce significant quantities of organic material, a portion of which is deposited in floodplain lakes. Deforestation in the watershed may then have potentially important effects on the carbon fluxes. In this study, a sediment core was extracted from an Amazon floodplain lake to examine the relationship between carbon burial and changing land cover and land use. Historical records from the 1930s and satellite data from the 1970s were used to calculate deforestation rates between 1930 to 1970 and 1970 to 2010 in four zones with different distances from the margins of the lake and its tributaries (100, 500, 1000 and 6000 m buffers). A sediment accumulation rate of ˜ 4 mm yr-1 for the previous ˜ 120 years was determined from the 240+239Pu signatures and the excess 210Pb method. The carbon burial rates ranged between 85 and 298 g C m-2 yr-1, with pulses of high carbon burial in the 1950s, originating from the forest vegetation as indicated by δ13C and δ15N signatures. Our results revealed a potentially important spatial dependence of the organic carbon (OC) burial in Amazon lacustrine sediments in relation to deforestation rates in the catchment. These deforestation rates were more intense in the riparian vegetation (100 m buffer) during the period 1930 to 1970 and the larger open water areas (500, 1000 and 6000 m buffer) during 1970 to 2010. The continued removal of vegetation from the interior of the forest was not related to the peak of OC burial in the lake, but only the riparian deforestation which peaked during the 1950s. Therefore, this supports the conservation priority of riparian forests as an important management practice for Amazon flooded areas. Our findings suggest the importance of abrupt and temporary events in which some of the biomass released by deforestation, especially restricted to areas along open water edges, might reach the depositional environments in the floodplain of the Amazon Basin.

  4. Groundwater interactions with Lobelia lakes- effects on the aquatic plant, Littorella uniflora

    DEFF Research Database (Denmark)

    Ommen, Daniela Oliveira; Vinther, Hanne Fogh; Krüger, Laila

    Lake Hampen is representative of a group of lakes called Lobelia lakes. These are oligotrophic, clear water lakes which tend to have a low alkalinity. These lakes are termed “Lobelia lakes” due to the characteristic isoetid species which thrive in these conditions. Isoetids are small, evergreen...... aquatic plants whose leaves grow in a rosette form and have a large root base. The large root system enables the plants to better assimilate nutrients from the sediments, and the uptake of CO2 which is used for photosynthesis, and to release O2 into otherwise anoxic sediments. Lake Hampen is situated high...... up in the Jylland ridge and lies close to the groundwater boundary. This means that the groundwater flow between the aquifer and the lake is not constant, sometimes the groundwater flows from the aquifer into the lake (discharge) and other times it flows from the lake into the aquifer (recharge...

  5. Atlantic small-mammal: a dataset of communities of rodents and marsupials of the Atlantic forests of South America.

    Science.gov (United States)

    Bovendorp, Ricardo S; Villar, Nacho; de Abreu-Junior, Edson F; Bello, Carolina; Regolin, André L; Percequillo, Alexandre R; Galetti, Mauro

    2017-08-01

    The contribution of small mammal ecology to the understanding of macroecological patterns of biodiversity, population dynamics, and community assembly has been hindered by the absence of large datasets of small mammal communities from tropical regions. Here we compile the largest dataset of inventories of small mammal communities for the Neotropical region. The dataset reviews small mammal communities from the Atlantic forest of South America, one of the regions with the highest diversity of small mammals and a global biodiversity hotspot, though currently covering less than 12% of its original area due to anthropogenic pressures. The dataset comprises 136 references from 300 locations covering seven vegetation types of tropical and subtropical Atlantic forests of South America, and presents data on species composition, richness, and relative abundance (captures/trap-nights). One paper was published more than 70 yr ago, but 80% of them were published after 2000. The dataset comprises 53,518 individuals of 124 species of small mammals, including 30 species of marsupials and 94 species of rodents. Species richness averaged 8.2 species (1-21) per site. Only two species occurred in more than 50% of the sites (the common opossum, Didelphis aurita and black-footed pigmy rice rat Oligoryzomys nigripes). Mean species abundance varied 430-fold, from 4.3 to 0.01 individuals/trap-night. The dataset also revealed a hyper-dominance of 22 species that comprised 78.29% of all individuals captured, with only seven species representing 44% of all captures. The information contained on this dataset can be applied in the study of macroecological patterns of biodiversity, communities, and populations, but also to evaluate the ecological consequences of fragmentation and defaunation, and predict disease outbreaks, trophic interactions and community dynamics in this biodiversity hotspot. © 2017 by the Ecological Society of America.

  6. Impact of Catchment Area Activities on Water Quality in Small Retention Reservoirs

    Directory of Open Access Journals (Sweden)

    Oszczapińska Katarzyna

    2018-01-01

    Full Text Available The aim of the study was to evaluate catchment area impact on small water reservoirs condition in Podlasie. The researches were conducted in two different catchment areas. Topiło reservoir, located in Podlasie area in the south-east of Białowieża Forest, has typical sylvan catchment. Second reservoir, Dojlidy, is located also in Podlasie, in the south-east of Białystok as a part of Dojlidy Ponds. In contrast to Topiło, Dojlidy has agricultural catchment. Water samples collected from five sites along each reservoir were analysed for the presence of total nitrogen and phosphorus, chlorophyll “a”, reaction, turbidity and conductivity. Researches took place in spring, summer and autumn 2013 (Topiło Lake and 2014/2015 (Dojlidy. The lowest trophic state was observed in autumn and the highest in summer. Because of the high loads of phosphorus received by the reservoirs, this element did not limit primary production. Calculated TSI values based on total phosphorus were always markedly higher than calculated on chlorophyll-a and total nitrogen. Both reservoirs demonstrated TSI indexes specific to hypertrophic lakes due to large amount of total phosphorus.

  7. Impact of Catchment Area Activities on Water Quality in Small Retention Reservoirs

    Science.gov (United States)

    Oszczapińska, Katarzyna; Skoczko, Iwona; Szczykowska, Joanna

    2018-02-01

    The aim of the study was to evaluate catchment area impact on small water reservoirs condition in Podlasie. The researches were conducted in two different catchment areas. Topiło reservoir, located in Podlasie area in the south-east of Białowieża Forest, has typical sylvan catchment. Second reservoir, Dojlidy, is located also in Podlasie, in the south-east of Białystok as a part of Dojlidy Ponds. In contrast to Topiło, Dojlidy has agricultural catchment. Water samples collected from five sites along each reservoir were analysed for the presence of total nitrogen and phosphorus, chlorophyll "a", reaction, turbidity and conductivity. Researches took place in spring, summer and autumn 2013 (Topiło Lake) and 2014/2015 (Dojlidy). The lowest trophic state was observed in autumn and the highest in summer. Because of the high loads of phosphorus received by the reservoirs, this element did not limit primary production. Calculated TSI values based on total phosphorus were always markedly higher than calculated on chlorophyll-a and total nitrogen. Both reservoirs demonstrated TSI indexes specific to hypertrophic lakes due to large amount of total phosphorus.

  8. Responses of small mammals to clear-cutting in temperate and boreal forests of Europe: a meta-analysis and review

    OpenAIRE

    Bogdziewicz, Michał; Zwolak, Rafał

    2013-01-01

    We analyzed the responses of small mammals to clear-cutting in temperate and boreal forests in Europe. We conducted a meta-analysis of published research on most often studied small mammal species (the striped field mouse, the yellow-necked mouse, the wood mouse, the field vole, the common vole, the bank vole, the Eurasian harvest mouse, the common shrew and the Eurasian pygmy shrew), comparing their abundance on clear-cuts and in unharvested stands. For four other species (the gray-sided vol...

  9. Are our forests declining. Why

    International Nuclear Information System (INIS)

    Leygonie, R.

    1991-01-01

    This article first presents the historical background of recent events popularized under the names: acid rains, forests declines. The first major crisis was soil and lake acidifications in Scandinavian countries, then a fast forest decay, first in Germany, in the early eighties, then in a number of European countries, including France. These phenomena were attributed to atmospheric pollutions, essentially acidic pollution. The consequences were drastic legislations in Germany, then the European Directive on large combustion plants (November 1988). Another consequence was the UNECE Convention on long range transport of pollutants (1979). Observations in the field on tree declines (loss of needles or leaves, abnormal yellowings, soil studies, etc.) and laboratory experiments showed that causes are very complex, involving the low quality of soils, abnormal droughts, presence of pollutants in atmosphere, mainly ozone [fr

  10. Pinatubo Lake Chemistry and Degassing 1991-2010

    Science.gov (United States)

    Schwandner, F. M.; Newhall, C. G.; Christenson, B. W.; Apfelbeck, C. A.; Arpa, M. C. B.; Vaquilar, R.; Bariso, E.

    2016-12-01

    We review the history of degassing, bathymetry and water chemistry of the crater lake of Mt. Pinatubo (Philippines) using data obtained during 1991-2001, and 2010. In late 1992, the initial small lake had a significant acid-sulfate component from a volcanic degassing through a hydrothermal system and the lake, and anhydrite dissolution. Subsequently, this component was "drowned" by rainfall (2-4 m/y), meteoric groundwater draining from the crater walls into the lake, and a few neutral chloride crater wall springs. Conductivity-Temperature-Depth (CTD) measurements in August 2000 found a strong inverted thermal gradient below 20m depth, reaching over 70°C at 50-60 m depth. By January 2001 the lake had homogenized and was much cooler (27°C at all depths), and it was again well-mixed and still cool when re-surveyed in June 2001 and November 2010. By 2010, the lake was well mixed, at neutral pH, with no significant vertical or horizontal structure. Bubbling of a predominantly carbon dioxide (CO2) gas phase persists throughout the lake's history, some from 1991-92 magma and some from degassing of the long-standing (pre-1991) hydrothermal system fed from a deeper magmatic or mantle source. Crater wall fumaroles emit boiling-point hydrothermal gases dominated by water, air, and CO2.

  11. Terrestrial CDOM in Lakes of Yamal Peninsula: Connection to Lake and Lake Catchment Properties

    Directory of Open Access Journals (Sweden)

    Yury Dvornikov

    2018-01-01

    Full Text Available In this study, we analyze interactions in lake and lake catchment systems of a continuous permafrost area. We assessed colored dissolved organic matter (CDOM absorption at 440 nm (a(440CDOM and absorption slope (S300–500 in lakes using field sampling and optical remote sensing data for an area of 350 km2 in Central Yamal, Siberia. Applying a CDOM algorithm (ratio of green and red band reflectance for two high spatial resolution multispectral GeoEye-1 and Worldview-2 satellite images, we were able to extrapolate the a(λCDOM data from 18 lakes sampled in the field to 356 lakes in the study area (model R2 = 0.79. Values of a(440CDOM in 356 lakes varied from 0.48 to 8.35 m−1 with a median of 1.43 m−1. This a(λCDOM dataset was used to relate lake CDOM to 17 lake and lake catchment parameters derived from optical and radar remote sensing data and from digital elevation model analysis in order to establish the parameters controlling CDOM in lakes on the Yamal Peninsula. Regression tree model and boosted regression tree analysis showed that the activity of cryogenic processes (thermocirques in the lake shores and lake water level were the two most important controls, explaining 48.4% and 28.4% of lake CDOM, respectively (R2 = 0.61. Activation of thermocirques led to a large input of terrestrial organic matter and sediments from catchments and thawed permafrost to lakes (n = 15, mean a(440CDOM = 5.3 m−1. Large lakes on the floodplain with a connection to Mordy-Yakha River received more CDOM (n = 7, mean a(440CDOM = 3.8 m−1 compared to lakes located on higher terraces.

  12. Mercury in fish from the Pinchi Lake Region, British Columbia, Canada

    International Nuclear Information System (INIS)

    Weech, S.A.; Scheuhammer, A.M.; Elliott, J.E.; Cheng, K.M.

    2004-01-01

    Water, surface sediments, and <40 cm rainbow trout (Oncorhynchus mykiss) and northern pikeminnow (Ptychocheilus oregonensis) were collected from Pinchi Lake, British Columbia, and from several nearby reference lakes. Hg concentrations in sediment samples from Pinchi L. were highly elevated compared to sediments from reference lakes, especially in sites adjacent to and downstream of a former Hg mine. In both fish species examined, Hg concentration was positively related to age and/or fork length. In northern pikeminnow, Hg concentrations were also positively related to trophic level (δN). Hg concentrations in both fish species were highest in Pinchi L., and were higher in pikeminnow than in rainbow trout of similar size. Average Hg concentrations in small rainbow trout from all lakes, including Pinchi L., were lower than dietary levels reported to cause reproductive impairment in common loons (Gavia immer); however, Hg levels in small pikeminnow from Pinchi L. were sufficiently high to be of concern. The risk for Hg toxicity in the study area is greatest for animals that consume larger piscivorous fish such as larger northern pikeminnow or lake trout, which are known from previous studies to contain higher Hg concentrations

  13. A Synthesis of Sierran Forest Biomass Management Studies and Potential Effects on Water Quality

    Directory of Open Access Journals (Sweden)

    Peter J. Weisberg

    2010-09-01

    Full Text Available The Lake Tahoe basin, located along the California and Nevada border between the Carson and Sierra Nevada mountain ranges, represents a complex forested ecosystem consisting of numerous sub-watersheds and tributaries that discharge directly to Lake Tahoe. This synthesis focuses on historical and current nutrient pools and the effects of biomass management in watersheds of the basin relative to their potential impacts on nutrient (N, P related discharge water quality. An accumulating forest floor as a result of fire suppression has resulted in the build-up of large nutrient pools that now provide a “natural” source of long term nutrient availability to surface waters. As a consequence, stand and forest floor replacing wildfire may cause a large magnitude nutrient mobilization impact on runoff water quality. Hence, mechanical harvest and controlled burning have become popular management strategies. The most ecologically significant long-term effects of controlled fire appear to be the loss of C and N from the forest floor. Although the application of controlled fire may have some initial impact on overland/litter interflow nutrient loading, controlled burning in conjunction with mechanical harvest has the potential to improve runoff water quality by reducing N and P discharge and improving the overall health of forest ecosystems without the danger of a high intensity wildfire.

  14. Fluctuations of Lake Orta water levels: preliminary analyses

    Directory of Open Access Journals (Sweden)

    Helmi Saidi

    2016-04-01

    Full Text Available While the effects of past industrial pollution on the chemistry and biology of Lake Orta have been well documented, annual and seasonal fluctuations of lake levels have not yet been studied. Considering their potential impacts on both the ecosystem and on human safety, fluctuations in lake levels are an important aspect of limnological research. In the enormous catchment of Lake Maggiore, there are many rivers and lakes, and the amount of annual precipitation is both high and concentrated in spring and autumn. This has produced major flood events, most recently in November 2014. Flood events are also frequent on Lake Orta, occurring roughly triennially since 1917. The 1926, 1951, 1976 and 2014 floods were severe, with lake levels raised from 2.30 m to 3.46 m above the hydrometric zero. The most important event occurred in 1976, with a maximum level equal to 292.31 m asl and a return period of 147 years. In 2014 the lake level reached 291.89 m asl and its return period was 54 years. In this study, we defined trends and temporal fluctuations in Lake Orta water levels from 1917 to 2014, focusing on extremes. We report both annual maximum and seasonal variations of the lake water levels over this period. Both Mann-Kendall trend tests and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes, and logistic regression was used to detect trends in the number of flood events. Lake level decreased during winter and summer seasons, and a small but statistically non-significant positive trend was found in the number of flood events over the period. We provide estimations of return period for lake levels, a metric which could be used in planning lake flood protection measures.

  15. Carbon density and distribution of six Chinese temperate forests

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Quantifying forest carbon(C) storage and distribution is important for forest C cycling studies and terrestrial ecosystem modeling.Forest inventory and allometric approaches were used to measure C density and allocation in six representative temperate forests of similar stand age(42-59 years old) and growing under the same climate in northeastern China.The forests were an aspen-birch forest,a hardwood forest,a Korean pine plantation,a Dahurian larch plantation,a mixed deciduous forest,and a Mongolian oak forest.There were no significant differences in the C densities of ecosystem components(except for detritus) although the six forests had varying vegetation compositions and site conditions.However,the differences were significant when the C pools were normalized against stand basal area.The total ecosystem C density varied from 186.9 tC hm-2 to 349.2 tC hm-2 across the forests.The C densities of vegetation,detritus,and soil ranged from 86.3-122.7 tC hm-2,6.5-10.5 tC hm-2,and 93.7-220.1 tC hm-2,respectively,which accounted for 39.7% ± 7.1%(mean ± SD),3.3% ± 1.1%,and 57.0% ± 7.9% of the total C densities,respectively.The overstory C pool accounted for > 99% of the total vegetation C pool.The foliage biomass,small root(diameter < 5mm) biomass,root-shoot ratio,and small root to foliage biomass ratio varied from 2.08-4.72 tC hm-2,0.95-3.24 tC hm-2,22.0%-28.3%,and 34.5%-122.2%,respectively.The Korean pine plantation had the lowest foliage production efficiency(total biomass/foliage biomass:22.6 g g-1) among the six forests,while the Dahurian larch plantation had the highest small root production efficiency(total biomass/small root biomass:124.7 g g-1).The small root C density decreased with soil depth for all forests except for the Mongolian oak forest,in which the small roots tended to be vertically distributed downwards.The C density of coarse woody debris was significantly less in the two plantations than in the four naturally regenerated forests.The variability

  16. Just forest governance: how small learning groups can have big impact

    Energy Technology Data Exchange (ETDEWEB)

    Mayers, James; Bhattacharya, Prodyut; Diaw, Chimere [and others

    2009-10-15

    Forests are power bases, but often for the wrong people. As attention turns from making an international deal on REDD to making it work on the ground, the hunt will be on for practical ways of shifting power over forests towards those who enable and pursue sustainable forest-linked livelihoods. The Forest Governance Learning Group – an alliance active in Cameroon, Ghana, India, Indonesia, Malawi, Mozambique, South Africa, Uganda and Vietnam – has developed practical tactics for securing safe space, provoking dialogue, building constituencies, wielding evidence and interacting politically. It has begun to have significant impacts. To deepen and widen those impacts, FGLG seeks allies.

  17. Ubiquitous influence of wildfire emissions and secondary organic aerosol on summertime atmospheric aerosol in the forested Great Lakes region

    Science.gov (United States)

    Gunsch, Matthew J.; May, Nathaniel W.; Wen, Miao; Bottenus, Courtney L. H.; Gardner, Daniel J.; VanReken, Timothy M.; Bertman, Steven B.; Hopke, Philip K.; Ault, Andrew P.; Pratt, Kerri A.

    2018-03-01

    Long-range aerosol transport affects locations hundreds of kilometers from the point of emission, leading to distant particle sources influencing rural environments that have few major local sources. Source apportionment was conducted using real-time aerosol chemistry measurements made in July 2014 at the forested University of Michigan Biological Station near Pellston, Michigan, a site representative of the remote forested Great Lakes region. Size-resolved chemical composition of individual 0.5-2.0 µm particles was measured using an aerosol time-of-flight mass spectrometer (ATOFMS), and non-refractory aerosol mass less than 1 µm (PM1) was measured with a high-resolution aerosol mass spectrometer (HR-AMS). The field site was influenced by air masses transporting Canadian wildfire emissions and urban pollution from Milwaukee and Chicago. During wildfire-influenced periods, 0.5-2.0 µm particles were primarily aged biomass burning particles (88 % by number). These particles were heavily coated with secondary organic aerosol (SOA) formed during transport, with organics (average O/C ratio of 0.8) contributing 89 % of the PM1 mass. During urban-influenced periods, organic carbon, elemental carbon-organic carbon, and aged biomass burning particles were identified, with inorganic secondary species (ammonium, sulfate, and nitrate) contributing 41 % of the PM1 mass, indicative of atmospheric processing. With current models underpredicting organic carbon in this region and biomass burning being the largest combustion contributor to SOA by mass, these results highlight the importance for regional chemical transport models to accurately predict the impact of long-range transported particles on air quality in the upper Midwest, United States, particularly considering increasing intensity and frequency of Canadian wildfires.

  18. The paleolimnological development of the twin lakes Etujärvi and Takajärvi in Askola, southern Finland – implications for lake management

    Directory of Open Access Journals (Sweden)

    Samu E. Valpola

    2006-01-01

    Full Text Available The twin lakes Etujärvi and Takajärvi in Askola, southern Finland, are closely interconnected mesotrophic headwater lakes with a relatively small catchment area. Both of the lakes have suffered from eutrophication and its consequences. Remediation activities such as oxygenation and biomanipulation have not resolved the problems. In this study a large set of paleolimnological techniques (radiometric AMS dating, spherical carbonaceous particles analysis, sediment lithology, grain-size analysis, phosphorus fractionation, and diatom analysis were applied to put together the development of the basin and its water level fluctuations during the Holocene. The age for observed Trapa natans -horizons was determined, and lake management options were discussed. The studied lakes dried up after isolation from the Ancylus Lake at about 9500 cal. B.P. and remained at very low water level until ca. 8700–8500 cal. B.P. The mid-Holocene risein water level resulted in fluctuating water levels, and led to the most recent rise starting about 2500 cal. B.P. as wet and cool climate conditions prevailed. The pronounced water level fluctuations led to the extensive growth of peat deposits surrounding the lake andprobably also forced T. natans to disappear from lake flora. The unstable, erodable peat rims impact the lakes, causing heavy load of humic substances to the lake and presenting additional deterioration to their recreational value.

  19. Response of aquatic macrophytes to human land use perturbations in the watersheds of Wisconsin lakes, U.S.A.

    Science.gov (United States)

    Sass, Laura L.; Bozek, Michael A.; Hauxwell, Jennifer A.; Wagner, Kelly; Knight, Susan

    2010-01-01

    Aquatic macrophyte communities were assessed in 53 lakes in Wisconsin, U.S.A. along environmental and land use development gradients to determine effects human land use perturbations have on aquatic macrophytes at the watershed and riparian development scales. Species richness and relative frequency were surveyed in lakes from two ecoregions: the Northern Lakes and Forests Ecoregion and the Southeastern Wisconsin Till Plain Ecoregion. Lakes were selected along a gradient of watershed development ranging from undeveloped (i.e., forested), to agricultural to urban development. Land uses occurring in the watershed and in perimeters of different width (0–100, 0–200, 0–500, and 0–1000 m from shore, in the watershed) were used to assess effects on macrophyte communities. Snorkel and SCUBA were used to survey aquatic macrophyte species in 18 quadrats of 0.25 m2 along 14 transects placed perpendicular to shore in each lake. Effects of watershed development (e.g., agriculture and/or urban) were tested at whole-lake (entire littoral zone) and near-shore (within 7 m of shore) scales using canonical correspondence analysis (CCA) and linear regression. Overall, species richness was negatively related to watershed development, while frequencies of individual species and groups differed in level of response to different land use perturbations. Effects of land use in the perimeters on macrophytes, with a few exceptions, did not provide higher correlations compared to land use at the watershed scale. In lakes with higher total watershed development levels, introduced species, particularly Myriophyllumspicatum, increased in abundance and native species, especially potamids, isoetids, and floating-leaved plants, declined in abundance. Correlations within the northern and southeastern ecoregions separately were not significant. Multivariate analyses suggested species composition is driven by environmental responses as well as human development pressures. Both water

  20. Paleoenvironments, Evolution, and Geomicrobiology in a Tropical Pacific Lake: The Lake Towuti Drilling Project (TOWUTI)

    Science.gov (United States)

    Vogel, Hendrik; Russell, James M.; Bijaksana, Satria; Crowe, Sean; Fowle, David; Haffner, Douglas; King, John; Marwoto, Ristiyanti; Melles, Martin; von Rintelen, Thomas; Stevenson, Janelle; Watkinson, Ian; Wattrus, Nigel

    2014-05-01

    Lake Towuti (2.5°S, 121°E) is a, 560 km2, 200-m deep tectonic lake at the downstream end of the Malili lake system, a set of five, ancient (1-2 MYr) tectonic lakes in central Sulawesi, Indonesia. Lake Towuti's location in central Indonesia provides a unique opportunity to reconstruct long-term paleoclimate change in a crucially important yet understudied region- the Indo-Pacific warm pool (IPWP), heart of the El Niño-Southern Oscillation. The Malili Lakes have extraordinarily high rates of floral and faunal endemism, and the lakes are surrounded by one of the most diverse tropical forests on Earth. Drilling in Lake Towuti will identify the age and origin of the lake and the environmental and climatic context that shaped the evolution of this unique lacustrine and terrestrial ecosystem. The ultramafic (ophiolitic) rocks and lateritic soils surrounding Lake Towuti provide metal substrates that feed a diverse, exotic microbial community, analogous to the microbial ecosystems that operated in the Archean Oceans. Drill core will provide unique insight into long-term changes in this ecosystem, as well as microbial processes operating at depth in the sediment column. High-resolution seismic reflection data (CHIRP and airgun) combined with numerous long sediment piston cores collected from 2007-2013 demonstrate the enormous promise of Lake Towuti for an ICDP drilling campaign. Well-stratified sequences of up to 150 m thickness, uninterrupted by unconformities or erosional truncation, are present in multiple sub-basins within Towuti, providing ideal sites for long-term environmental, climatic, and limnological reconstructions. Multiproxy analyses of our piston cores document a continuous and detailed record of moisture balance variations in Lake Towuti during the past 60 kyr BP. In detail our datasets show that wet conditions and rainforest ecosystems in central Indonesia persisted during Marine Isotope Stage 3 (MIS3) and the Holocene, and were interrupted by severe

  1. Glacial lakes of the Central and Patagonian Andes

    Science.gov (United States)

    Wilson, Ryan; Glasser, Neil F.; Reynolds, John M.; Harrison, Stephan; Anacona, Pablo Iribarren; Schaefer, Marius; Shannon, Sarah

    2018-03-01

    The prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3 during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

  2. The aspen mortality summit; December 18 and 19, 2006; Salt Lake City, UT

    Science.gov (United States)

    Dale L. Bartos; Wayne D. Shepperd

    2010-01-01

    The USDA Forest Service Rocky Mountain Research Station sponsored an aspen summit meeting in Salt Lake City, Utah, on December 18 and19, 2006, to discuss the rapidly increasing mortality of aspen (Populus tremuloides) throughout the western United States. Selected scientists, university faculty, and managers from Federal, State, and non-profit agencies with experience...

  3. Forest die-back modified plankton recovery from acidic stress

    Czech Academy of Sciences Publication Activity Database

    Vrba, J.; Kopáček, Jiří; Fott, J.; Nedbalová, L.

    2014-01-01

    Roč. 43, č. 2 (2014), s. 207-217 ISSN 0044-7447 R&D Projects: GA ČR(CZ) GA206/07/1200; GA ČR(CZ) GAP504/12/1218 Institutional support: RVO:60077344 Keywords : atmospheric acidification * Bohemian Forest * lake recovery * phytoplankton * zooplankton Subject RIV: DJ - Water Pollution ; Quality Impact factor: 2.289, year: 2014

  4. Angora Fire, Lake Tahoe

    Science.gov (United States)

    2007-01-01

    On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  5. Regionalisation for lake level simulation – the case of Lake Tana in the Upper Blue Nile, Ethiopia

    Directory of Open Access Journals (Sweden)

    T. H. M. Rientjes

    2011-04-01

    Full Text Available In this study lake levels of Lake Tana are simulated at daily time step by solving the water balance for all inflow and outflow processes. Since nearly 62% of the Lake Tana basin area is ungauged a regionalisation procedure is applied to estimate lake inflows from ungauged catchments. The procedure combines automated multi-objective calibration of a simple conceptual model and multiple regression analyses to establish relations between model parameters and catchment characteristics.

    A relatively small number of studies are presented on Lake Tana's water balance. In most studies the water balance is solved at monthly time step and the water balance is simply closed by runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments characteristics. For runoff modelling the HBV-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. We aim to assess the closure term of Lake Tana's water balance, to assess model parameter uncertainty and to evaluate effectiveness of a multi-objective model calibration approach to make hydrological modeling results more plausible.

    For the gauged catchments, model performance is assessed by the Nash-Sutcliffe coefficient and Relative Volumetric Error and resulted in satisfactory to good performance for six, large catchments. The regional model is validated and indicated satisfactory to good performance in most cases. Results show that runoff from ungauged catchments is as large as 527 mm per year for the simulation period and amounts to approximately 30% of Lake Tana stream inflow. Results of daily lake level simulation over the simulation period 1994–2003 show a water balance closure term of 85 mm per year that accounts to 2.7% of the total lake inflow. Lake level

  6. Biogeochemistry of Lakes in Western Papua, Indonesia - First Results of a Pilot Study.

    Science.gov (United States)

    Kallmeyer, J.; Nomosatryo, S.; Henny, C.; Kopalit, H.

    2016-12-01

    Despite years of exploration for mineral and hydrocarbon resources, the lakes of Western Papua have received very little attention from a limnogeologic perspective. In some cases not even the maximum water depth of the lakes is published. The only research carried out so far focused on the fish and invertebrate fauna of the lakes, because the macrofauna of Papuan Lakes is significantly different from other islands of western Indonesia. Most lakes harbor numerous endemic species. We carried out a first limnogeologic pilot campaign in spring 2016 to measure water column profiles and take short (max 80 cm long) sediment cores.Lake Sentani is seated in Mesozoic mafic bedrock and consists of four separate basins with maximum water depths of 30 to 40 m. Three basins are connected by shallow sills and one by a natural canal. Although all four basins share almost identical surface water chemistry and exhibit sub- to anoxic bottom waters, each basin has its distinct water column stratification and sediment geochemistry. Despite its coastal location and minimal elevation we could not identify an influx of seawater into the lake. Lake Ayamaru is located further inland on a densely forested karstified carbonate platform. The lake level has dropped significantly in recent years due to water loss into the karst, further reduction of open water surface is caused by massive growth of Pistia. Currently the lake has a maximum depth of around 2 m. Its sediment is mainly composed of carbonate minerals and methane saturated. Due to the carbonate bedrock the lake is highly alkaline (up to 20 meq/L) despite its very low salinity. The initial analyses show that these lakes offer unique biogeochemical conditions that require further in-depth studies.Our research will expand to lakes Anggi Giji and Anggi Gida, which are at almost 2000 m elevation. They have maximum depths of around 200 m and much colder surface waters (12-20°C) compared to the other two lakes that have about 30

  7. Sanctuaries for lake trout in the Great Lakes

    Science.gov (United States)

    Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

    1987-01-01

    Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

  8. Global-Scale Patterns of Forest Fragmentation

    Directory of Open Access Journals (Sweden)

    Kurt Riitters

    2000-12-01

    Full Text Available We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 x 9 pixels, "small" scale to 59,049 km 2 (243 x 243 pixels, "large" scale were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents, there were significant differences among individual forest types. Tropical rain forest fragmentation was most severe in North America and least severe in Europe-Asia. Forest types with a high percentage of perforated conditions were mainly in North America (five types and Europe-Asia (four types, in both temperate and subtropical regions. Transitional and patch conditions were most common in 11 forest types, of which only a few would be considered as "naturally patchy" (e.g., dry woodland. The five forest types with the highest percentage of interior conditions were in North America; in decreasing order, they were cool rain forest, coniferous, conifer boreal, cool mixed, and cool broadleaf.

  9. Global-scale patterns of forest fragmentation

    Science.gov (United States)

    Riitters, K.; Wickham, J.; O'Neill, R.; Jones, B.; Smith, E.

    2000-01-01

    We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 ?? 9 pixels, "small" scale) to 59,049 km 2 (243 ?? 243 pixels, "large" scale) were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined) from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents, there were significant differences among individual forest types. Tropical rain forest fragmentation was most severe in North America and least severe in Europe - Asia. Forest types with a high percentage of perforated conditions were mainly in North America (five types) and Europe - Asia (four types), in both temperate and subtropical regions. Transitional and patch conditions were most common in 11 forest types, of which only a few would be considered as "naturally patchy" (e.g., dry woodland). The five forest types with the highest percentage of interior conditions were in North America; in decreasing order, they were cool rain forest, coniferous, conifer boreal, cool mixed, and cool broadleaf. Copyright ?? 2000 by The Resilience Alliance.

  10. Ecosystem responses during Late Glacial period recorded in the sediments of Lake Łukie (East Poland)

    Science.gov (United States)

    Zawiska, Izabela; Słowiński, Michał; Correa-Metrio, Alex; Obremska, Milena; Luoto, Tomi; Nevalainen, Liisa; Woszczyk, Michał; Milecka, Krystyna

    2014-05-01

    catchment of Lake Łukie, pioneer birch-pine forests dominated, later replaced by pine-birch forests. Consequently this limited the erosion. The results of all proxy suggest the water-lever rise in lake Łukie. The Younger Dryas cooling in the region began about 12 630 14C years BP and recorded in significant drop in temperature reconstructed with plant macrofossils and Cladocera. The cooling resulted in a decline of forest communities and development of open habitats with grasses (Poaceae), Artemisia, and Chenopodiaceae), as well as juniper thickets (Juniperus) At the end of the Younger Dryas, plant communities changed, the non-arborescent pollen declined, while pollen of trees (especially Pinus) became more abundant. This change was more abruptly reflected in Cladocera and aquatic pollen results and is probably related to gradual climate warming. This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association, projects UMO-2011/01/B/ST10/07367 and N N306 036436 founded by National Science Center, Poland.

  11. Seasonal and spatial patterns of microbial diversity along a trophic gradient in the interconnected lakes of the Osterseen Lake District, Bavaria

    Science.gov (United States)

    Zwirglmaier, Katrin; Keiz, Katharina; Engel, Marion; Geist, Juergen; Raeder, Uta

    2015-01-01

    The Osterseen Lake District in Bavaria consists of 19 small interconnected lakes that exhibit a pronounced trophic gradient from eutrophic to oligotrophic. It therefore presents a unique model system to address ecological questions regarding niche adaptation and Baas Becking's long standing hypothesis of “everything is everywhere, but the environment selects.” Here, we present the first assessment of the microbial diversity in these lakes. We sampled the lakes in August and December and used 454 pyrosequencing of 16S rRNA amplicons to analyze the microbial diversity. The diversity patterns between lakes and seasons were compared and the bacterial community composition was correlated with key chemical and physical parameters. Distinct patterns of bacterial diversity only emerged at the level of individual OTUs (operational taxonomic units), but not at the level of the major bacterial phyla. This emphasizes the high functional and physiological diversity among bacterial species within a phylum and calls for analysis of biodiversity at the level of OTUs in order to understand fine-scale biogeography. We were able to identify a number of cosmopolitan OTUs as well as specialist OTUs that were restricted to certain lakes or seasons, suggesting adaptation to specific ecological niches. PMID:26579082

  12. Field performance of timber bridges. 7, Connell Lake stress-laminated deck bridge

    Science.gov (United States)

    L. E. Hislop; M. A. Ritter

    The Connell Lake bridge was constructed in early 1991 on the Tongass National Forest, Alaska, as a demonstration bridge under the Timber Bridge Initiative. The bridge is a stress-laminated deck structure with an approximate 36-ft length and 18-ft width and is the first known stress-laminated timber bridge constructed in Alaska. Performance of the bridge was monitored...

  13. Resilience in Source to Sink Systems: A Millennial Record of Watershed Responses to Disturbance in Loon Lake, Umpqua River Basin, Oregon

    Science.gov (United States)

    Guerrero, F. J.; Richardson, K.; Hatten, J. A.

    2017-12-01

    Small mountainous watersheds are disproportionate sources of particulate organic matter (POM) to long-term sinks like lake bottoms and the ocean. Thus, alterations in sediment routing resulting from disturbances (e.g. earthquakes, fires, and timber harvesting) have profound consequences on watershed's (biogeochemical) resilience. The assessment of these biogeochemical impacts is complicated by the episodic signal propagation along these source-to-sink systems and therefore is seldom attempted. We report on a 1500-year record of historical changes in Loon Lake, a local sedimentary sink (1.2 km2) for a 230 km2 watershed in the Oregon Coast Range. Particle size distributions and POM elemental composition (C, N) were sampled at high temporal resolution ( 3 years). Stable isotopic composition and lignin biomarkers were sampled with varying temporal resolution depending on the period analyzed: 1939-2013 (3-year resolution); 515-1939 (15-year resolution). Disturbance history in Loon Lake catchment is recorded as a sequence of event beds deposited in sharp contrast within a matrix of background sedimentation. At least 8 out of 23 event beds were associated with >8.2 magnitude earthquakes (including the 9.0 megathrust earthquake in 1700). Forest fires in 1770 and 1890 were also recorded as event beds. After 1939, event beds record the impacts of landscape destabilization due to the interaction between intense storms and timber harvesting. At the onset of each event, %C, %N, and C:N ratios increased reflecting the input of coarse POM from surficial soil horizons. Top layers bracketing event beds are rich in clays and have low %C, suggesting a deep-soil sediment source. Isotopic signatures (i.e. δ13C, δ15N) confirm the allochthony of sediment inputs during events and lignin biomarkers suggest a replacement of riparian inputs by a strong gymnosperm signal, particularly after 1945. Thus, event beds record changes in the relative importance of different sediment sources within

  14. Liming as a method to remedy lakes contaminated by radiostrontium

    International Nuclear Information System (INIS)

    Haakanson, Lars

    2003-01-01

    This work has identified the characteristics regulating lake sensitivity to 90 Sr-contamination and why certain lakes are likely to respond positively to lake liming (Ca-treatment) and when this would not be a feasible or economic remedial measure to lower 90 Sr-levels in fish. The results demonstrate that liming would work best in (1) small, (2) low-productive, (3) oligohumic, (4) acid lakes with (5) low initial Ca-concentrations. It is important to start the liming as soon as possible after the fallout. The liming model discussed in this work can be used to calculate the changes in lake Ca-concentrations and the duration of the liming. The Sr-model can be used to calculate changes in Sr-levels in water, sediments and fish. At best, these simulations indicate that it is realistic to expect that lake liming can reduce peak levels of 90 Sr in fish by 25-40%

  15. Eastern Africa Coastal Forest Programme

    OpenAIRE

    Younge, A.

    2002-01-01

    The eastern African coastal forest ecoregion is recognised as one of Africa’s centres of species endemism, and is distributed over six countries (Somalia, Kenya, Tanzania, Mozambique, Zimbabwe and Malawi). Most is found in Kenya, Tanzania and Mozambique, which form our focal region. The coastal forests are fragmented, small and surrounded by poor communities that have a high demand for land and forest resources. Although coastal forests have significant cultural and traditional...

  16. A synthesis of rates and controls on elemental mercury evasion in the Great Lakes Basin

    International Nuclear Information System (INIS)

    Denkenberger, Joseph S.; Driscoll, Charles T.; Branfireun, Brian A.; Eckley, Chris S.; Cohen, Mark; Selvendiran, Pranesh

    2012-01-01

    Rates of surface-air elemental mercury (Hg 0 ) fluxes in the literature were synthesized for the Great Lakes Basin (GLB). For the majority of surfaces, fluxes were net positive (evasion). Digital land-cover data were combined with representative evasion rates and used to estimate annual Hg 0 evasion for the GLB (7.7 Mg/yr). This value is less than our estimate of total Hg deposition to the area (15.9 Mg/yr), suggesting the GLB is a net sink for atmospheric Hg. The greatest contributors to annual evasion for the basin are agricultural (∼55%) and forest (∼25%) land cover types, and the open water of the Great Lakes (∼15%). Areal evasion rates were similar across most land cover types (range: 7.0–21.0 μg/m 2 -yr), with higher rates associated with urban (12.6 μg/m 2 -yr) and agricultural (21.0 μg/m 2 -yr) lands. Uncertainty in these estimates could be partially remedied through a unified methodological approach to estimating Hg 0 fluxes. - Highlights: ► Considerable variability exists across spatial/temporal scales in Hg 0 evasion rates. ► Methodological approaches vary for estimating and reporting gaseous Hg 0 fluxes. ► Hg 0 evasion from the Great Lakes Basin is estimated at 7.7 Mg/yr (10.2 μg/m 2 -yr). ► Hg flux estimates suggest region is a net sink for atmospheric Hg. ► 95% of Hg 0 evasion in the region is from agriculture, forest, and the Great Lakes. - A synthesis of Hg evasion was conducted and this information was used to develop an estimate of Hg evasion for the Great Lakes Basin.

  17. MERGANSER: an empirical model to predict fish and loon mercury in New England lakes.

    Science.gov (United States)

    Shanley, James B; Moore, Richard; Smith, Richard A; Miller, Eric K; Simcox, Alison; Kamman, Neil; Nacci, Diane; Robinson, Keith; Johnston, John M; Hughes, Melissa M; Johnston, Craig; Evers, David; Williams, Kate; Graham, John; King, Susannah

    2012-04-17

    MERGANSER (MERcury Geo-spatial AssessmeNtS for the New England Region) is an empirical least-squares multiple regression model using mercury (Hg) deposition and readily obtainable lake and watershed features to predict fish (fillet) and common loon (blood) Hg in New England lakes. We modeled lakes larger than 8 ha (4404 lakes), using 3470 fish (12 species) and 253 loon Hg concentrations from 420 lakes. MERGANSER predictor variables included Hg deposition, watershed alkalinity, percent wetlands, percent forest canopy, percent agriculture, drainage area, population density, mean annual air temperature, and watershed slope. The model returns fish or loon Hg for user-entered species and fish length. MERGANSER explained 63% of the variance in fish and loon Hg concentrations. MERGANSER predicted that 32-cm smallmouth bass had a median Hg concentration of 0.53 μg g(-1) (root-mean-square error 0.27 μg g(-1)) and exceeded EPA's recommended fish Hg criterion of 0.3 μg g(-1) in 90% of New England lakes. Common loon had a median Hg concentration of 1.07 μg g(-1) and was in the moderate or higher risk category of >1 μg g(-1) Hg in 58% of New England lakes. MERGANSER can be applied to target fish advisories to specific unmonitored lakes, and for scenario evaluation, such as the effect of changes in Hg deposition, land use, or warmer climate on fish and loon mercury.

  18. Evolution of alkaline lakes - Lake Van case study

    Science.gov (United States)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic activity (e.g.: tephra layers, deformation structures, slumping) in the Lake Van sedimentary profile around 530 ka, it seems unlikely that a pyroclastic flow blocked the outflow of the lake. Alternatively, a portion of inflow has been diverged which might have caused a change in the hydrological balance and lake level falling below its outlet. However, as no geomorphological data confirming this

  19. Metal ion complex formation in small lakes of the Western Siberian Arctic zone

    Science.gov (United States)

    Kremleva, Tatiana; Dinu, Marina

    2017-04-01

    The paper is based on joint investigation of the Tyumen State University (Russia, Tyumen) and the Geochemistry and Analytical Chemistry Vernadsky Institute of Russian Academy of Sciences (Moscow, Russia) during 2012-2014 period. It presents the results of research of chemical composition of about 70 small lakes located in the area of tundra and northern taiga of West Siberia (Russia, Yamal-Nenets and Khanty-Mansi Autonomous Districts of the Tyumen region). The investigation includes determination of different parameters of natural water samples: • content of trace elements (Al, Fe, Mn, Cr, Cu, Ni, Zn, Cd, Co, Pb, etc., total more than 60 elements) by emission method with an inductively coupled plasma (ICP-MS) using mass spektrometrometre Element 2 equipment; • content of inorganic and total carbon (TIC and TC) by elemental analysis and the difference between the total and inorganic carbon gives the organic carbon content (TOC); • pH value by potentiometric method; • content of basic ions (Na+, Ca2+, K+, Mg2+, NH4+, Cl-, SO42-, NO3-, PO43-) by ion chromatography. Determination of the chemical composition of samples was conducted in the accredited laboratory according to standard procedures with regular quality control of results. Heavy metals in natural waters can exist in various forms: free (hydrated) ions bound in complexes with organic or inorganic ligands, as well as in the form of suspensions. The form of metal existence has a significant influence on their availability to transport in aquatic organisms. Metal ions associated in stable complexes with organic substances are considered less toxic. From the previous investigations state that the most stable complexes are ligands with organic ions Fe3+, Al3+. The main conclusion of the present research states that if the total content of aluminum, iron and manganese ions (meq/dm3) is equal to or greater than the concentration of dissolved organic carbon (TOC, mg/dm3) in lakes water other heavy metals will

  20. Habitat Evaluation Procedures (HEP) Report; Gamblin Lake, Technical Report 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Entz, Ray

    2005-05-01

    On August 12, 2003, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the Gamblin Lake property, an acquisition completed by the Kalispel Tribe of Indians in December 2002. Evaluation species and appropriate models include bald eagle, black-capped chickadee, mallard, muskrat, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The Gamblin Lake Project provides a total of 273.28 Habitat Units (HUs) for the species evaluated. Conifer forest habitat provides 127.92 HUs for bald eagle, black-capped chickadee, mallard, and white-tailed deer. Forested wetland habitat provides 21.06 HUs for bald eagle, black-caped chickadee, mallard, and white-tailed deer. Wet meadow provides 78.05 HUs for Canada goose and mallard. Emergent wetland habitat provides 46.25 HUs for mallard, muskrat, and Canada goose. The objective of using HEP at the Gamblin Lake Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at future points in time so that the effect of management activities on wildlife habitat can be quantified. When combined with other tools, the baseline HEP will be used to determine the most effective on-site management, restoration, and enhancement actions to increase habitat suitability for targeted species. The same process will be replicated every five years to quantitatively evaluate the effectiveness of management strategies in improving and maintaining habitat conditions while providing additional crediting to BPA for enhanced habitat values.

  1. Cordova Lake dam hydroelectric generating station case study

    International Nuclear Information System (INIS)

    Kerr, D.; Huxley, J.

    1993-01-01

    The Ontario Ministry of Natural Resources released a Crown owned site to the private water power industry as part of the small hydro site release program initiated by the Ontario Government in the mid 1980's. The Cordova Lake Dam Hydroelectric Generating Station, built on this site, has been in operation since the first week of October, 1992. Since that time, the plant has been operating with less than 1 % down time and has generated over 2,400 MWh of electricity. Algonquin Power Systems is responsible for the management and operations of the plant which includes full time monitoring from the company's Mississauga office and a part time employee at Cordova Lake. Cordova Lake Dam is located on the Crowe River at the outlet of Cordova Lake, approximately 125 kilometers east of Toronto, Ontario. The total cost of the Cordova Lake Dam project was $1.6 million. Algonquin Power contributed 20% equity to the project. Algonquin Power was also responsible for all engineering and geotechnical work and for completing the construction and equipment contracts. 1 tab., 2 figs

  2. LIMNOLOGICAL CONDITION AND ESTIMATION OF POTENTIAL FISH PRODUCTION OF KERINCI LAKE JAMBI, SUMATRA

    Directory of Open Access Journals (Sweden)

    Samuel Samuel

    2015-06-01

    Full Text Available Kerinci Lake is a type of tectonic lakes located in a protected forest area of National Park of Kerinci Sebelat and a source of various fish species important for local people for their dayly food comsumption and income. However, few information is available on limnological condition and fish resources. Field research observing the limnological condition and estimating the potential fish production was conducted four times in April, June, August and October 2013. The research is aimed to describe the condition of limnology and estimate the potential fish production of the lake. Limnological aspect included the physico-chemical and biological parameters, namely: temperature, water transparency, depth, substrate, conductivity, pH, dissolved oxygen, alkalinity, ammonia, nitrate, phosphate, total phosphorus, chlorophyll-a and trophic state. Potential fish production was calculated by using the biological parameter levels of chlorophyll-a. The results show that the euphotic layer of the lake waters was still feasible for fish life. Water condition of the bottom layer was less supportable for fish life due to low dissolved oxygen content. Trophic state index (TSI values, either measured by temporal and spatial ways, had TSI with an average of 61.75. From these index, the lake is classified as a lake at the high productivity level (eutrophic. Annual fish production was an average of 307 kg/ha/year. By taking account the average of fish production and the total area of lake of around 4,200 ha, the potential fish production of Kerinci Lake is estimated about ± 1,287 tons/year.

  3. The contribution of lakes to global inland fisheries harvest

    Science.gov (United States)

    Deines, Andrew M.; Bunnell, David B.; Rogers, Mark W.; Bennion, David; Woelmer, Whitney; Sayers, Michael J.; Grimm, Amanda G.; Shuchman, Robert A.; Raymer, Zachary B.; Brooks, Colin N.; Mychek-Londer, Justin G.; Taylor, William W.; Beard, Douglas

    2017-01-01

    Freshwater ecosystems provide numerous services for communities worldwide, including irrigation, hydropower, and municipal water; however, the services provided by inland fisheries – nourishment, employment, and recreational opportunities – are often comparatively undervalued. We provide an independent estimate of global lake harvest to improve biological and socioeconomic assessments of inland fisheries. On the basis of satellite-derived estimates of chlorophyll concentration from 80,012 globally distributed lakes, lake-specific fishing effort based on human population, and output from a Bayesian hierarchical model, we estimated that the global lake fishery harvest in the year 2011 was 8.4 million tons (mt). Our calculations excluded harvests from highly productive rivers, wetlands, and very small lakes; therefore, the true cumulative global fishery harvest from all freshwater sources likely exceeded 11 mt as reported by the Food and Agriculture Organization of the United Nations (FAO). This putative underestimate by the FAO could diminish the perceived importance of inland fisheries and perpetuate decisions that adversely affect these fisheries and millions of people.

  4. Soil Erosion Analysis in a Small Forested Catchment Supported by ArcGIS Model Builder

    Directory of Open Access Journals (Sweden)

    CSÁFORDI, Péter

    2012-01-01

    Full Text Available To implement the analysis of soil erosion with the USLE in a GIS environment, a new workflow has been developed with the ArcGIS Model Builder. The aim of this four-part framework is to accelerate data processing and to ensure comparability of soil erosion risk maps. The first submodel generates the stream network with connected catchments, computes slope conditions and the LS factor in USLE based on the DEM. The second submodel integrates stream lines, roads, catchment boundaries, land cover, land use, and soil maps. This combined dataset is the basis for the preparation of other USLE-factors. The third submodel estimates soil loss, and creates zonal statistics of soil erosion. The fourth submodel classifies soil loss into categories enabling the comparison of modelled and observed soil erosion. The framework was applied in a small forested catchment in Hungary. Although there is significant deviation between the erosion of different land covers, the predicted specific soil loss does not increase above the tolerance limit in any area unit. The predicted surface soil erosion in forest subcompartments mostly depends on the slope conditions.

  5. 78 FR 33433 - Bear Lake National Wildlife Refuge, Bear Lake County, ID, and Oxford Slough Waterfowl Production...

    Science.gov (United States)

    2013-06-04

    ... Lake NWR, with enhancements to improve access. Hunting of waterfowl, small game, upland game birds, big..., including opportunities for hunting, fishing, wildlife observation and photography, and environmental... feasibility of, and make recommendations on, techniques to exclude carp and non-native game fish within the...

  6. Recognizing loss of open forest ecosystems by tree densification and land use intensification in the Midwestern USA

    Science.gov (United States)

    Brice B. Hanberry; Marc D. Abrams

    2018-01-01

    Forests and grasslands have changed during the past 200 years in the eastern USA, and it is now possible to quantify loss and conversion of vegetation cover at regional scales. We quantified historical (ca. 1786-1908) and current land cover and determined long-term ecosystem change to either land use or closed forests in eight states of the Great Lakes and Midwest....

  7. Bathymetry of Lake Erie and Lake Saint Clair

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

  8. Ethiopian church forests : opportunities and challenges for restoration

    NARCIS (Netherlands)

    Wassie Eshete, A.

    2007-01-01

    In Northern Ethiopia almost all dry Afromontane forests have been converted to open agricultural lands. Only small isolated fragments remain around churches ("church forests"), but these are many. This study analyses forest community structure and composition of the church forests, investigates

  9. Historical changes in the ecosystem condition of a small mountain lake over the past 60 years as revealed by plankton remains and Daphnia ephippial carapaces stored in lake sediments.

    Directory of Open Access Journals (Sweden)

    Hajime Ohtsuki

    Full Text Available To examine if changes in species composition of a plankton community in the past due to anthropogenic activities can be clarified in lakes without any monitoring data, we analyzed genetically ephippial carapaces of Daphnia with plankton remains stored in the bottom sediments of Lake Hataya Ohunma in Japan. In the lake, abundance of most plankton remains in the sediments was limited and TP flux was at low levels (2-4 mg/m2/y before 1970. However TP flux increased two-fold during the period from 1980s to 1990 s. In parallel with this increase, abundance of most plankton remains increased although abundance of benthic testate amoebae's remains decreased, indicating that the lake trophic condition had changed from oligo- to mesotrophic for the past 60 years. According to cluster analysis, the stratigraphic sediments were divided into two periods with different features of the phytoplankton composition. Chronological comparison with events in the watershed suggested that eutrophication occurred because of an increase in visitors to the watershed and deposition of atmospheric dust. In this lake more than 50% of resting eggs produced by Daphnia over the past 60 years hatched. However, genetic analysis of the ephippial carapaces (remains showed that the Daphnia population was originally composed of D. dentifera but that D. galeata, or its hybrid with D. dentifera, invaded and increased the population density when the lake was eutrophied. Subsequently, large D. pulex established populations in the 1980s when largemouth bass were anonymously introduced. These results indicated that the Lake Hataya Ohunma plankton community underwent significant changes despite the fact that there were no notable changes in land cover or land use in the watershed. Since increases in atmospheric deposition and release of fish have occurred in many Japanese lakes, the changes in the plankton community described here may be widespread in these lakes.

  10. Development of a zoning-based environmental-ecological-coupled model for lakes to assess lake restoration effect

    Science.gov (United States)

    Xu, Mengjia; Zou, Changxin; Zhao, Yanwei

    2017-04-01

    Environmental/ecological models are widely used for lake management as they provide a means to understand physical, chemical and biological processes in highly complex ecosystems. Most research focused on the development of environmental (water quality) and ecological models, separately. Limited studies were developed to couple the two models, and in these limited coupled models, a lake was regarded as a whole for analysis (i.e., considering the lake to be one well-mixed box), which was appropriate for small-scale lakes and was not sufficient to capture spatial variations within middle-scale or large-scale lakes. This paper seeks to establish a zoning-based environmental-ecological-coupled model for a lake. The Baiyangdian Lake, the largest freshwater lake in Northern China, was adopted as the study case. The coupled lake models including a hydrodynamics and water quality model established by MIKE21 and a compartmental ecological model used STELLA software have been established for middle-sized Baiyangdian Lake to realize the simulation of spatial variations of ecological conditions. On the basis of the flow field distribution results generated by MIKE21 hydrodynamics model, four water area zones were used as an example for compartmental ecological model calibration and validation. The results revealed that the developed coupled lake models can reasonably reflected the changes of the key state variables although there remain some state variables that are not well represented by the model due to the low quality of field monitoring data. Monitoring sites in a compartment may not be representative of the water quality and ecological conditions in the entire compartment even though that is the intention of compartment-based model design. There was only one ecological observation from a single monitoring site for some periods. This single-measurement issue may cause large discrepancies particularly when sampled site is not representative of the whole compartment. The

  11. Forest Patch Size, Land Use, and Mesic Forest Herbs in the French Broad River Basin, North Carolina

    Science.gov (United States)

    Scott M. Pearson; Alan B. Smith; Monica G. Turner

    1998-01-01

    The effect of forest fragmentation on cove-forest herbs was studied in the Southern Blue Ridge Province. Patches of mesic forests were sampled with 4 ha study plots. The coverage and density of herb species were greater in large patches (>200 ha) than in small patches (

  12. A catchment-scale carbon and greenhouse gas budget of a subarctic landscape

    DEFF Research Database (Denmark)

    Christensen, Torben R; Johansson, Torbjörn; Olsrud, Maria

    2007-01-01

    forest, and mires, lakes and alpine ecosystems. The magnitudes of atmospheric exchange of carbon in the form of the GHGs, CO2 and CH4 in these various ecosystems differ significantly, ranging from little or no flux in barren ecosystems over a small CO2 sink function and low rates of CH4 exchange...... in the heaths to significant CO2 uptake in the forests and also large emissions of CH4 from the mires and small lakes. The overall catchment budget, given the size distribution of the individual ecosystem types and a first approximation of run-off as dissolved organic carbon, reveals a landscape currently...

  13. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    Science.gov (United States)

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  14. The origin of shallow lakes in the Khorezm Province, Uzbekistan, and the history of pesticide use around these lakes

    Science.gov (United States)

    Rosen, Michael R.; Crootof, Arica; Reidy, Liam; Saito, Laurel; Nishonov, Bakhriddin; Scott, Julian A.

    2018-01-01

    The economy of the Khorezm Province in Uzbekistan relies on the large-scale agricultural production of cotton. To sustain their staple crop, water from the Amu Darya is diverted for irrigation through canal systems constructed during the early to mid-twentieth century when this region was part of the Soviet Union. These diversions severely reduce river flow to the Aral Sea. The Province has >400 small shallow (data indicate that the majority of the lakes investigated are less than 150 years old, which supports a recent origin of the lakes. The thickness of lacustrine sediments in the cores analyzed ranged from 20 to 60 cm in all but two of the lakes, indicating a relatively slow sedimentation rate and a relatively short-term history for the lakes. Hydrologic changes in the lakes are evident from loss on ignition and pollen analyses of a subset of the lake cores. The data indicate that the lakes have transitioned from a dry, saline, arid landscape during pre-lake conditions (low organic carbon content) and low pollen concentrations (in the basal sediments) to the current freshwater lakes (high organic content), with abundant freshwater pollen taxa over the last 50–70 years. Sediments at the base of the cores contain pollen taxa dominated by Chenopodiaceae and Tamarix, indicating that the vegetation growing nearby was tolerant to arid saline conditions. The near surface sediments of the cores are dominated by Typha/Sparganium, which indicate freshwater conditions. Increases in pollen of weeds and crop plants indicate an intensification of agricultural activities since the 1950s in the watersheds of the lakes analyzed. Pesticide profiles of DDT (dichlorodiphenyltrichloroethane) and its degradates and γ-HCH (gamma-hexachlorocyclohexane), which were used during the Soviet era, show peak concentrations in the top 10 cm of some of the cores, where estimated ages of the sediments (1950–1990) are associated with peak pesticide use during the Soviet era. These data

  15. Lake trout demographics in relation to burbot and coregonine populations in the Algonquin Highlands, Ontario

    Science.gov (United States)

    Carl, L.M.

    2008-01-01

    The objective of the study was to test the hypothesis that lake trout populations change in relation to cisco, lake whitefish, round whitefish and burbot populations in lakes in the Algonquin Highlands region of Ontario. Lake trout population change is greatest where cisco and lake whitefish are present. Lake trout populations in lakes without either coregonine tend to have small adults and many juveniles. Where cisco or lake whitefish are present, adult lake trout are large, juvenile abundance is low, and the stock-recruit relationship appears to be uncoupled likely due to a larval bottleneck. Lake trout populations in these lakes may be sensitive to overfishing and recruitment failure. Lake trout populations do not appear to change in relation to round whitefish. There appears to be an indirect positive change on juvenile lake trout abundance through reductions in the density of benthic coregonines in the presence of large, hypolimnetic burbot. ?? 2007 Springer Science+Business Media B.V.

  16. A multi-proxy approach to understanding complex responses of salt-lake catchments to climate variability and human pressure: A Late Quaternary case study from south-eastern, Spain

    Science.gov (United States)

    Jones, Samantha Elsie; Burjachs, Francesc; Ferrer-García, Carlos; Giralt, Santiago; Schulte, Lothar; Fernández-López de Pablo, Javier

    2018-03-01

    This article focuses on a former salt lake in the upper Vinalopó Valley in south-eastern Spain. The study spans the Late Pleistocene through to the Late Holocene, although with particular focus on the period between 11 ka cal BP and 3000 ka cal BP (which spans the Mesolithic and part of the Bronze Age). High resolution multi-proxy analysis (including pollen, non pollen palynomorphs, grain size, X-ray fluorescence and X-ray diffraction) was undertaken on the lake sediments. The results show strong sensitivity to both long term and small changes in the evaporation/precipitation ratio, affecting the surrounding vegetation composition, lake-biota and sediment geochemistry. To summarise the key findings the main general trends identified include: 1) Hyper-saline conditions and low lake levels at the end of the Late Glacial 2) Increasing wetness and temperatures which witnessed an expansion of mesophilic woodland taxa, lake infilling and the establishment of a more perennial lake system at the onset of the Holocene 3) An increase in solar insolation after 9 ka cal BP which saw the re-establishment of pine forests 4) A continued trend towards increasing dryness (climatic optimum) at 7 ka cal BP but with continued freshwater input 5) An increase in sclerophyllous open woody vegetation (anthropogenic?), and increasing wetness (climatic?) is represented in the lake record between 5.9 and 3 ka cal BP 6) The Holocene was also punctuated by several aridity pulses, the most prominent corresponding to the 8.2 ka cal BP event. These events, despite a paucity of well dated archaeological sites in the surrounding area, likely altered the carrying capacity of this area both regionally and locally, particularly during the Mesolithic-Neolithic transition, in terms of fresh water supply for human/animal consumption, wild plant food reserves and suitable land for crop growth.

  17. Riparian ecosystem resilience and livelihood strategies under test: lessons from Lake Chilwa in Malawi and other lakes in Africa.

    Science.gov (United States)

    Kafumbata, Dalitso; Jamu, Daniel; Chiotha, Sosten

    2014-04-05

    This paper reviews the importance of African lakes and their management challenges. African inland lakes contribute significantly to food security, livelihoods and national economies through direct exploitation of fisheries, water resources for irrigation and hydropower generation. Because of these key contributions, the ecosystem services provided are under significant stress mainly owing to high demand by increasing populations, negative anthropogenic impacts on lake catchments and high levels of poverty which result in unsustainable use. Climate variability exacerbates the stress on these ecosystems. Current research findings show that the lakes cannot sustain further development activities on the scale seen over the past few decades. Millions of people are at risk of losing livelihoods through impacts on livestock and wildlife. The review further shows that the problems facing these lakes are beyond the purview of current management practices. A much better understanding of the interactions and feedbacks between different components of the lake socio-ecological systems is needed to address the complex challenges of managing these ecosystem services. This review suggests that the three small wetlands of Chad, Chilwa and Naivasha provide an opportunity for testing novel ideas that integrate sustainability of natural resource management with livelihoods in order to inform policy on how future land use and climatic variability will affect both food security and the ecosystem services associated with it.

  18. PREDICTED SEDIMENTARY SECTION OF SUBGLACIAL LAKE VOSTOK

    Directory of Open Access Journals (Sweden)

    G. I. Leychenkov

    2012-01-01

    Full Text Available In early February 2012, the drill hole at the Vostok Station encountered theLakeVostokwater. This step is important to study the lake composition including possible microbial life and to model subglacial environments however, the next ambitious target of the Vostok Drilling Project is sampling of bottom sediments, which contain the unique record of ice sheet evolution and environmental changes in centralAntarcticafor millions of years. In this connection, the forecast of sedimentary succession based on existing geophysical data, study of mineral inclusions in the accretion ice cores and tectonic models is important task. Interpretation of Airborne geophysical data suggests thatLakeVostokis the part of spacious rift system, which exists at least from Cretaceous. Reflection and refraction seismic experiments conducted in the southern part ofLakeVostokshow very thin (200–300 m stratified sedimentary cover overlying crystalline basement with velocity of 6.0–6.2 km/s. At present, deposition in southernLakeVostokis absent and similar conditions occurred likely at least last3 m.y. when ice sheet aboveLakeVostokchanged insignificantly. It can be also inferred that from the Late Miocene the rate of deposition inLakeVostokwas extremely low and so the most of sedimentary section is older being possibly of Oligocene to early to middle Miocene age when ice sheet oscillated and deposition was more vigorous. If so, the sampling of upper few meters of this condensed section is very informative in terms of history of Antarctic glaciation. Small thickness of sedimentary cover raises a question about existence of lake (rift depression during preglacial and early glacial times.

  19. Impacts of nutrients and pesticides from small- and large-scale agriculture on the water quality of Lake Ziway, Ethiopia.

    Science.gov (United States)

    Teklu, Berhan M; Hailu, Amare; Wiegant, Daniel A; Scholten, Bernice S; Van den Brink, Paul J

    2018-05-01

    The area around Lake Ziway in Ethiopia is going through a major agricultural transformation with both small-scale farmers and large horticultural companies using pesticides and fertilisers at an increased rate. To be able to understand how this influences the water quality of Lake Ziway, water quality data was gathered to study the dynamics of pesticide concentrations and physicochemical parameters for the years from 2009 to 2015. Results indicate that for some physicochemical parameters, including pH, potassium and iron, over 50 % of the values were above the maximum permissible limit of the Ethiopian standard for drinking water. The fungicide spiroxamine poses a high chronic risk when the water is used for drinking water, while the estimated intake of diazinon was approximately 50 % of the acceptable daily intake. Higher-tier risk assessment indicated that the fungicide spiroxamine poses a high acute risk to aquatic organisms, while possible acute risks were indicated for the insecticides deltamethrin and endosulfan. Longer-term monitoring needs to be established to show the water quality changes across time and space, and the current study can be used as a baseline measurement for further research in the area as well as an example for other surface water systems in Ethiopia and Africa.

  20. Preliminary Study of the Effect of the Proposed Long Lake Valley Project Operation on the Transport of Larval Suckers in Upper Klamath Lake, Oregon

    Science.gov (United States)

    Wood, Tamara M.

    2009-01-01

    A hydrodynamic model of Upper Klamath and Agency Lakes, Oregon, was used to explore the effects of the operation of proposed offstream storage at Long Lake Valley on transport of larval suckers through the Upper Klamath and Agency Lakes system during May and June, when larval fish leave spawning sites in the Williamson River and springs along the eastern shoreline and become entrained in lake currents. A range in hydrologic conditions was considered, including historically high and low outflows and inflows, lake elevations, and the operation of pumps between Upper Klamath Lake and storage in Long Lake Valley. Two wind-forcing scenarios were considered: one dominated by moderate prevailing winds and another dominated by a strong reversal of winds from the prevailing direction. On the basis of 24 model simulations that used all combinations of hydrology and wind forcing, as well as With Project and No Action scenarios, it was determined that the biggest effect of project operations on larval transport was the result of alterations in project management of the elevation in Upper Klamath Lake and the outflow at the Link River and A Canal, rather than the result of pumping operations. This was because, during the spring time period of interest, the amount of water pumped between Upper Klamath Lake and Long Lake Valley was generally small. The dominant effect was that an increase in lake elevation would result in more larvae in the Williamson River delta and in Agency Lake, an effect that was enhanced under conditions of wind reversal. A decrease in lake elevation accompanied by an increase in the outflow at the Link River had the opposite effect on larval concentration and residence time.

  1. Validation of CryoSat-2 SAR mode based lake levels

    DEFF Research Database (Denmark)

    Nielsen, Karina; Stenseng, Lars; Andersen, Ole Baltazar

    2015-01-01

    Lake level serve as an important indicator of the climate and continuous measurements are therefore essential. Satellite radar altimetry has now been used successfully for more than two decades to measure lake level as an addition to gauge measurements. The technique has, due to the large footprint...... with water levels obtained from Envisat. We find that the along-track precision of the mean based on CryoSat-2 is a few centimeter, even for the small lakes, which is a significant improvement compared to previous missions such as Envisat. When validating against gauge data we find RMS values of differences...

  2. Glacial lake inventory and lake outburst potential in Uzbekistan.

    Science.gov (United States)

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-08-15

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m 2 . As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Loss of biodiversity in a conservation unit of the Brazilian Atlantic Forest: the effect of introducing non-native fish species

    Directory of Open Access Journals (Sweden)

    E. N. Fragoso-Moura

    Full Text Available Abstract The introduction of species has become an important problem for biodiversity and natural ecosystem conservation. The lake system of the middle Rio Doce (MG, Brazil comprises c. 200 lakes at various conservation states, of which 50 are located within the Rio Doce State Park (PERD. Previous studies had verified several of these lakes suffered non-native fishes introductions and the presence of these species needs for the implementation of actions aiming at not only their control but also the preservation of the native species. This study discusses the effects of non-native fish species in the largest conservation unit of Atlantic Forest in Minas Gerais, southeast of Brazil, using data from 1983 to 2010 distributed as follow: data prior to 2006 were obtained from previous studies, and data from September 2006 to July 2010 were obtained in Lake Carioca at four sampling stations using gillnets, seine nets and sieve. A total of 17 fish species was collected (2006-2010 of which five were introduced species. Among the small to medium size native species (30 to 2000 mm standard length seven had disappeared, two are new records and one was recaptured. The non-native species Cichla kelberi (peacock bass and Pygocentrus nattereri (red piranha are within the most abundant captured species. Integrated with other actions, such as those preventing new introductions, a selective fishing schedule is proposed as an alternative approach to improve the conservation management actions and the local and regional biodiversity maintenance.

  4. Loss of biodiversity in a conservation unit of the Brazilian Atlantic Forest: the effect of introducing non-native fish species.

    Science.gov (United States)

    Fragoso-Moura, E N; Oporto, L T; Maia-Barbosa, P M; Barbosa, F A R

    2016-02-01

    The introduction of species has become an important problem for biodiversity and natural ecosystem conservation. The lake system of the middle Rio Doce (MG, Brazil) comprises c. 200 lakes at various conservation states, of which 50 are located within the Rio Doce State Park (PERD). Previous studies had verified several of these lakes suffered non-native fishes introductions and the presence of these species needs for the implementation of actions aiming at not only their control but also the preservation of the native species. This study discusses the effects of non-native fish species in the largest conservation unit of Atlantic Forest in Minas Gerais, southeast of Brazil, using data from 1983 to 2010 distributed as follow: data prior to 2006 were obtained from previous studies, and data from September 2006 to July 2010 were obtained in Lake Carioca at four sampling stations using gillnets, seine nets and sieve. A total of 17 fish species was collected (2006-2010) of which five were introduced species. Among the small to medium size native species (30 to 2000 mm standard length) seven had disappeared, two are new records and one was recaptured. The non-native species Cichla kelberi (peacock bass) and Pygocentrus nattereri (red piranha) are within the most abundant captured species. Integrated with other actions, such as those preventing new introductions, a selective fishing schedule is proposed as an alternative approach to improve the conservation management actions and the local and regional biodiversity maintenance.

  5. The Finnish multisource national forest inventory: small-area estimation and map production

    Science.gov (United States)

    Erkki Tomppo

    2009-01-01

    A driving force motivating development of the multisource national forest inventory (MS-NFI) in connection with the Finnish national forest inventory (NFI) was the desire to obtain forest resource information for smaller areas than is possible using field data only without significantly increasing the cost of the inventory. A basic requirement for the method was that...

  6. Ecosystem services of human-dominated watersheds and land use influences: a case study from the Dianchi Lake watershed in China.

    Science.gov (United States)

    Hou, Ying; Li, Bo; Müller, Felix; Chen, Weiping

    2016-11-01

    Watersheds provide multiple ecosystem services. Ecosystem service assessment is a promising approach to investigate human-environment interaction at the watershed scale. The spatial characteristics of ecosystem services are closely related to land use statuses in human-dominated watersheds. This study aims to investigate the effects of land use on the spatial variations of ecosystem services at the Dianchi Lake watershed in Southwest China. We investigated the spatial variations of six ecosystem services-food supply, net primary productivity (NPP), habitat quality, evapotranspiration, water yield, and nitrogen retention. These services were selected based on their significance at the Dianchi Lake watershed and the availability of their data. The quantification of these services was based on modeling, value transference, and spatial analysis in combination with biophysical and socioeconomic data. Furthermore, we calculated the values of ecosystem services provided by different land use types and quantified the correlations between ecosystem service values and land use area proportions. The results show considerable spatial variations in the six ecosystem services associated with land use influences in the Dianchi Lake watershed. The cropland and forest land use types had predominantly positive influences on food productivity and NPP, respectively. The rural residential area and forest land use types reduced and enhanced habitat quality, respectively; these influences were identical to those of evapotranspiration. Urban area and rural residential area exerted significantly positive influences on water yield. In contrast, water yield was negatively correlated with forest area proportion. Finally, cropland and forest had significantly positive and negative influences, respectively, on nitrogen retention. Our study emphasizes the importance of consideration of the influences from land use composition and distribution on ecosystem services for managing the ecosystems of

  7. Differential sensitivity to natural ultraviolet radiation among phytoplankton species in Arctic lakes (Spitsbergen, Norway)

    NARCIS (Netherlands)

    Donk, van E.; Faafeng, B.A.; Lange, de H.J.

    2001-01-01

    Incubation experiments demonstrated a differential sensitivity to natural UV-radiation among the dominant phytoplankton species from three Arctic lakes, situated near Ny-Ålesund, Spitsbergen (79° N). The growth of small chlorophytes, diatoms and picocyanobacteria from two oligotrophic lakes was

  8. Climatic and pollution influences on ecosystem processes in northern hardwood forests

    Science.gov (United States)

    Kurt S. Pregitzer; David D. Reed; Glenn D. Mroz; Andrew J. Burton; John A. Witter; Donald A. Zak

    1996-01-01

    The Michigan gradient study was established in 1987 to examine the effects of climate and atmospheric deposition on forest productivity and ecosystem processes in the Great Lakes region. Four intensively-monitored northern hardwood study sites are located along a climatic and pollutant gradient extending from southern lower Michigan to northwestern upper Michigan. The...

  9. The evolution of a thermokarst-lake landscape: Late Quaternary permafrost degradation and stabilization in interior Alaska

    Science.gov (United States)

    Edwards, Mary E.; Grosse, Guido; Jones, Benjamin M.; McDowell, Patricia F.

    2016-01-01

    Thermokarst processes characterize a variety of ice-rich permafrost terrains and often lead to lake formation. The long-term evolution of thermokarst landscapes and the stability and longevity of lakes depend upon climate, vegetation and ground conditions, including the volume of excess ground ice and its distribution. The current lake status of thermokarst-lake landscapes and their future trajectories under climate warming are better understood in the light of their long-term development. We studied the lake-rich southern marginal upland of the Yukon Flats (northern interior Alaska) using dated lake-sediment cores, observations of river-cut exposures, and remotely-sensed data. The region features thick (up to 40 m) Quaternary deposits (mainly loess) that contain massive ground ice. Two of three studied lakes formed ~ 11,000–12,000 cal yr BP through inferred thermokarst processes, and fire may have played a role in initiating thermokarst development. From ~ 9000 cal yr BP, all lakes exhibited steady sedimentation, and pollen stratigraphies are consistent with regional patterns. The current lake expansion rates are low (0 to drainage, nor of multiple lake generations within a basin. However, LiDAR images reveal linear “corrugations” (> 5 m amplitude), deep thermo-erosional gullies, and features resembling lake drainage channels, suggesting that highly dynamic surface processes have previously shaped the landscape. Evidently, widespread early Holocene permafrost degradation and thermokarst lake initiation were followed by lake longevity and landscape stabilization, the latter possibly related to establishment of dense forest cover. Partial or complete drainage of three lakes in 2013 reveals that there is some contemporary landscape dynamism. Holocene landscape evolution in the study area differs from that described from other thermokarst-affected regions; regional responses to future environmental change may be equally individualistic.

  10. ASTER measurement of supraglacial lakes in the Mount Everest region of the Himalaya

    Science.gov (United States)

    Wessels, R.L.; Kargel, J.S.; Kieffer, H.H.

    2002-01-01

    We demonstrate an application of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images to detect and monitor supraglacial lakes on glaciers in the Mount Everest region in Tibet (Xizang) and Nepal. ASTER offers powerful capabilities to monitor supraglacial lakes in terms of (1) surface area, growth and disappearance (spatial resolution = 15 m), (2) turbidity (15 m resolution), and (3) temperature (90 m resolution). Preliminary results show an overall similarity of supraglacial lakes on three glaciers. Lakes have widely varying turbidity as indicated by color in visible/near-infrared bands 1-3, the largest lakes being bright blue (highly turbid), cold (near 0??C) and hydrautically connected with other lakes and supraglacial streams, while small lakes are mostly dark blue (relatively clear water), warmer (>4??C), and appear hydrautically isolated. High levels of turbidity in supraglacial lakes indicate high rates of meltwater input from streams or erosion of ice cliffs, and thus are an indirect measure relating to the activity and hydraulic integration of the lake with respect to other lakes and streams in the glacier.

  11. Population and harvest trends of big game and small game species: a technical document supporting the USDA Forest Service Interim Update of the 2000 RPA Assessment

    Science.gov (United States)

    Curtis H. Flather; Michael S. Knowles; Stephen J. Brady

    2009-01-01

    This technical document supports the Forest Service's requirement to assess the status of renewable natural resources as mandated by the Forest and Rangeland Renewable Resources Planning Act of 1974 (RPA). It updates past reports on national and regional trends in population and harvest estimates for species classified as big game and small game. The trends...

  12. Historic carbon burial spike in an Amazon floodplain lake linked to riparian deforestation near Santarém, Brazil

    Directory of Open Access Journals (Sweden)

    L. M. Sanders

    2018-01-01

    Full Text Available Forests along the Amazon Basin produce significant quantities of organic material, a portion of which is deposited in floodplain lakes. Deforestation in the watershed may then have potentially important effects on the carbon fluxes. In this study, a sediment core was extracted from an Amazon floodplain lake to examine the relationship between carbon burial and changing land cover and land use. Historical records from the 1930s and satellite data from the 1970s were used to calculate deforestation rates between 1930 to 1970 and 1970 to 2010 in four zones with different distances from the margins of the lake and its tributaries (100, 500, 1000 and 6000 m buffers. A sediment accumulation rate of  ∼ 4 mm yr−1 for the previous  ∼ 120 years was determined from the 240+239Pu signatures and the excess 210Pb method. The carbon burial rates ranged between 85 and 298 g C m−2 yr−1, with pulses of high carbon burial in the 1950s, originating from the forest vegetation as indicated by δ13C and δ15N signatures. Our results revealed a potentially important spatial dependence of the organic carbon (OC burial in Amazon lacustrine sediments in relation to deforestation rates in the catchment. These deforestation rates were more intense in the riparian vegetation (100 m buffer during the period 1930 to 1970 and the larger open water areas (500, 1000 and 6000 m buffer during 1970 to 2010. The continued removal of vegetation from the interior of the forest was not related to the peak of OC burial in the lake, but only the riparian deforestation which peaked during the 1950s. Therefore, this supports the conservation priority of riparian forests as an important management practice for Amazon flooded areas. Our findings suggest the importance of abrupt and temporary events in which some of the biomass released by deforestation, especially restricted to areas along open water edges, might reach the depositional environments in

  13. Uranium Geochemistry in Hypersaline Soda Lakes in Eastern Mongolia

    Science.gov (United States)

    Linhoff, B. S.; Bennett, P.; Puntsag, T.

    2007-12-01

    Extremely high concentrations of uranium were discovered in water samples from hypersaline soda lakes in eastern Mongolia. The origin and fate of uranium in these lakes was examined using geochemical analyses and modeling, using samples collected from five lakes, six wells and one stream. Samples were analyzed for strontium and uranium isotopes, cations and trace metals, anions, alkalinity, and unstable field parameters. The lakes are small, shallow (chlorine to bromine ratios implying groundwater discharges to lake water and is subsequently evaporated. Evaporation is intense with lake waters having average chlorine concentrations 300 times that of well waters. Uranium in well samples is higher than typical for shallow groundwaters (7-101ppb) suggesting discharging groundwater as a probable source of uranium in lake water. Concentrations of uranium in lake water ranges from 57-14,900ppb making these lakes possibly the highest naturally occurring uranium concentration reported. Lake water alkalinity is strongly correlated to uranium abundance suggesting uranium is complexed with carbonate as the aqueous species UO2CO3. Consequently, the extremely high alkalinity of the most alkaline lake (pH = 9.8, 1288.8 meq alk/L) also has the highest uranium concentrations. Stable strontium isotopes were used to assess the degree of water rock interactions and the presence of 90Sr was checked for to test the possibility of input of nuclear fallout. 90Sr was not detected in lake water samples suggesting the high uranium is of natural origins. A large difference in the 87Sr/86Sr ratio was found between groundwater and lake water samples. Groundwater samples displayed large variation in the 87Sr/86Sr ratio (0.70612-0.709776) whereas lake water samples averaged a high radiogenic ratio (0.709432). The large variation in the strontium isotopes in groundwater samples suggests varying degrees of water rock interactions, however the least radiogenic samples likely are derived from

  14. Lake Superior Coastal Wetland Fish Assemblages and ...

    Science.gov (United States)

    The role of the coastal margin and the watershed context in defining the ecology of even very large lakes is increasingly being recognized and examined. Coastal wetlands are both important contributors to the biodiversity and productivity of large lakes and important mediators of the lake-basin connection. We explored wetland-watershed connections and their relationship to wetland function and condition using data collected from 37 Lake Superior wetlands spanning a substantial geographic and geomorphic gradient. While none of these wetlands are particularly disturbed, there were nevertheless clear relationships between watershed landuse and wetland habitat and biota, and these varied consistently across wetland type categories that reflected the strength of connection to the watershed. For example, water clarity and vegetation structure complexity declined with decreasing percent natural land cover, and these effects were strongest in riverine wetlands (having generally large watersheds and tributary-dominated hydrology) and weakest in lagoon wetlands (having generally small watersheds and lake-dominate hydrology). Fish abundance and species richness both increased with decreasing percent natural land cover while species diversity decreased, and again the effect was strongest in riverine wetlands. Lagoonal wetlands, which lack any substantial tributary, consistently harbored the fewest species of fish and a composition different from the more watershed-lin

  15. Lake-level frequency analysis for Devils Lake, North Dakota

    Science.gov (United States)

    Wiche, Gregg J.; Vecchia, Aldo V.

    1996-01-01

    Two approaches were used to estimate future lake-level probabilities for Devils Lake. The first approach is based on an annual lake-volume model, and the second approach is based on a statistical water mass-balance model that generates seasonal lake volumes on the basis of seasonal precipitation, evaporation, and inflow. Autoregressive moving average models were used to model the annual mean lake volume and the difference between the annual maximum lake volume and the annual mean lake volume. Residuals from both models were determined to be uncorrelated with zero mean and constant variance. However, a nonlinear relation between the residuals of the two models was included in the final annual lakevolume model.Because of high autocorrelation in the annual lake levels of Devils Lake, the annual lake-volume model was verified using annual lake-level changes. The annual lake-volume model closely reproduced the statistics of the recorded lake-level changes for 1901-93 except for the skewness coefficient. However, the model output is less skewed than the data indicate because of some unrealistically large lake-level declines. The statistical water mass-balance model requires as inputs seasonal precipitation, evaporation, and inflow data for Devils Lake. Analysis of annual precipitation, evaporation, and inflow data for 1950-93 revealed no significant trends or long-range dependence so the input time series were assumed to be stationary and short-range dependent.Normality transformations were used to approximately maintain the marginal probability distributions; and a multivariate, periodic autoregressive model was used to reproduce the correlation structure. Each of the coefficients in the model is significantly different from zero at the 5-percent significance level. Coefficients relating spring inflow from one year to spring and fall inflows from the previous year had the largest effect on the lake-level frequency analysis.Inclusion of parameter uncertainty in the model

  16. Lake trout in northern Lake Huron spawn on submerged drumlins

    Science.gov (United States)

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  17. The upland flooding experiment : assessing the impact of reservoir creation on the biogeochemical cycling of mercury in boreal forest uplands

    Energy Technology Data Exchange (ETDEWEB)

    Rolfhus, K.R. [Wisconsin Univ., Madison, WI (United States). Water Chemistry Program; Bodaly, R.A.; Fudge, R.J.P.; Huebert, D.; Paterson, M.J. [Department of Fisheries and Oceans, Ottawa, ON (Canada) Fresh Water Inst.; Hall, B.D.; St Louis, V.L. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences; Krabbenhoft, D.P. [U.S. Geological Survey (United States); Hurley, J.P. [Wisconsin Univ., Madison, WI (United States). Water Resources Inst.; Peech, K. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Entomology

    2000-07-01

    One of the major environmental problems associated with boreal hydroelectric reservoirs such as those found in Canada and other northern countries is the elevated concentrations of mercury (Hg) in fish. A flooding experiment was conducted in northern Ontario to study methyl mercury (MeHg) production/bioaccumulation and greenhouse gas dynamics in impoundments with flooded upland forests of different soil carbon content, moisture and vegetation. The study, entitled Upland Flooding Experiment (FLUDEX) took place in June 1999 at the Experimental Lakes Area (ELA) where three impoundments of 0.7 ha were flooded to a depth of 1 m using oligotrophic lake water. The hydraulic residence time was 10-14 days. Responses to flooding were compared among treatment reservoirs and to previously flooded wetlands. The study included researchers from Canada and the United States who characterized mercury species fluxes from soils, the overall reservoir mass balance for total Hg and MeHg, inorganic Hg and MeHg concentration in zooplankton, benthic invertebrates, emerging insects and fish. Carbon decomposition was also examined. Preliminary results, one year after inundation, show significantly high levels of MeHg concentration compared to the feed water and that of surrounding natural lakes. Outflow samples from the dry forest areas showed the highest concentrations of Hg and MeHg, with lower concentrations from the moist forest. The lowest levels were observed from the outflow from the driest forest reservoir. A rapid pulse of inorganic Hg appears to have been released during the first 2 weeks of flooding. Soil leaching was found to be the main mechanism or inorganic Hg supply while MeHg appears to have been supplied by in situ microbial methylation. It was also shown that forage fish introduced into the reservoir had significantly elevated concentrations of MeHg compared to fish in natural lakes.

  18. Habitat Evaluation Procedures (HEP) Report; North Eaton Lake, Technical Report 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Entz, Ray

    2005-11-01

    On July 6, 2005, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the North Eaton Lake property, an acquisition completed by the Kalispel Tribe of Indians in November 2004. Evaluation species and appropriate models include bald eagle, black-capped chickadee, Canada goose, mallard, muskrat, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The North Eaton Lake Project provides a total of 235.05 Habitat Units (HUs) for the species evaluated. Open water habitat provides 9.38 HUs for Canada goose, mallard and muskrat. Emergent wetland habitat provides 11.36 HUs for Canada goose, mallard and muskrat. Forested wetland provides 10.97 HUs for bald eagle, black-capped chickadee, mallard and white-tailed deer. Conifer forest habitat provides 203.34 HUs for bald eagle, black-capped chickadee, mallard, and white-tailed deer. The objective of using HEP at the North Eaton Lake Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at future points in time so that the effect of management activities on wildlife habitat can be quantified. When combined with other tools, the baseline HEP will be used to determine the most effective on-site management, restoration, and enhancement actions to increase habitat suitability for targeted species. The same process will be replicated every five years to quantitatively evaluate the effectiveness of management strategies in improving and maintaining habitat conditions while providing additional crediting to BPA for enhanced habitat values.

  19. Divergence in Forest-Type Response to Climate and Weather: Evidence for Regional Links Between Forest-Type Evenness and Net Primary Productivity

    Science.gov (United States)

    Bradford, J.B.

    2011-01-01

    Climate change is altering long-term climatic conditions and increasing the magnitude of weather fluctuations. Assessing the consequences of these changes for terrestrial ecosystems requires understanding how different vegetation types respond to climate and weather. This study examined 20 years of regional-scale remotely sensed net primary productivity (NPP) in forests of the northern Lake States to identify how the relationship between NPP and climate or weather differ among forest types, and if NPP patterns are influenced by landscape-scale evenness of forest-type abundance. These results underscore the positive relationship between temperature and NPP. Importantly, these results indicate significant differences among broadly defined forest types in response to both climate and weather. Essentially all weather variables that were strongly related to annual NPP displayed significant differences among forest types, suggesting complementarity in response to environmental fluctuations. In addition, this study found that forest-type evenness (within 8 ?? 8 km2 areas) is positively related to long-term NPP mean and negatively related to NPP variability, suggesting that NPP in pixels with greater forest-type evenness is both higher and more stable through time. This is landscape- to subcontinental-scale evidence of a relationship between primary productivity and one measure of biological diversity. These results imply that anthropogenic or natural processes that influence the proportional abundance of forest types within landscapes may influence long-term productivity patterns. ?? 2011 Springer Science+Business Media, LLC (outside the USA).

  20. Impact of Forest Harvesting and Forest Regeneration on Runoff Dynamics at Watersheds of Central Siberia

    Directory of Open Access Journals (Sweden)

    A. A. Onuchin

    2014-02-01

    Full Text Available In the paper disturbance of Angara river region forests were estimated and peculiarities of forest regeneration after logging and wild fires were analyzed. According to the landscape classification of the regional study, three groups of landscapes differencing on types of forest successions were developed. It was shown that water protective and water regulate functions of the Angara river region forests change under commercial forest harvesting. Comparisons of the inventory and hydrological data detected that hydrological consequences of commercial forest harvesting are dependent on climatic parameters and forest regeneration peculiarities. In the continental climate conditions, when forest regeneration is delayed, snow storms are more active, snow evaporation increases and runoff reduces. In the process of logging sites overgrown with secondary small-leaved forest, snow accumulation increases and runoff increases, exceeding the value of annual runoff at undisturbed watersheds.

  1. Relations of biological indicators to nutrient data for lakes and streams in Pennsylvania and West Virginia, 1990-98

    Science.gov (United States)

    Brightbill, Robin A.; Koerkle, Edward H.

    2003-01-01

    The Clean Water Action Plan of 1998 provides a blueprint for federal agencies to work with states, tribes, and other stakeholders to protect and restore the Nation's water resources. The plan includes an initiative that addresses the nutrient-enrichment problem of lakes and streams across the United States. The U.S. Environmental Protection Agency (USEPA) is working to set nutrient criteria by nationwide nutrient ecoregions that are an aggregation of the Omernik level III ecoregions. Because low levels of nutrients are necessary for healthy streams and elevated concentrations can cause algal blooms that deplete available oxygen and kill off aquatic organisms, criteria levels are to be set, in part, using the relation between chlorophyll a and concentrations of total nitrogen and total phosphorus.Data from Pennsylvania and West Virginia, collected between 1990 and 1998, were analyzed for relations between chlorophyll a, nutrients, and other explanatory variables. Both phytoplankton and periphyton chlorophyll a concentrations from lakes and streams were analyzed separately within each of the USEPA nutrient ecoregions located within the boundaries of the two states. These four nutrient ecoregions are VII (Mostly Glaciated Dairy), VIII (Nutrient Poor, Largely Glaciated Upper Midwest and Northeast), IX (Southeastern Temperate Forested Plains and Hills), and XI (Central and Eastern Forested Uplands).Phytoplankton chlorophyll a concentrations in lakes were related to total nitrogen, total phosphorus, Secchi depth, concentration of dissolved oxygen, pH, water temperature, and specific conductivity. In nutrient ecoregion VII, nutrients were not significant predictors of chlorophyll a concentrations. Total nitrogen, Secchi depth, and pH were significantly related to phytoplankton chlorophyll a concentrations in nutrient ecoregion IX. Lake periphyton chlorophyll a concentrations from nutrient ecoregion XI were related to total phosphorus rather than total nitrogen, Secchi

  2. Lake trout rehabilitation in Lake Erie: a case history

    Science.gov (United States)

    Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

    1995-01-01

    Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

  3. Lake fish as the main contributor of internal dose to lakeshore residents in the Chernobyl contaminated area

    International Nuclear Information System (INIS)

    Travnikova, I.G.; Bazjukin, A.N.; Bruk, G.Ja.; Shutov, V.N.; Balonov, M.I.; Skuterud, L.; Mehli, H.; Strand, P.

    2004-01-01

    Two field expeditions in 1996 studied 137 Cs intake patterns and its content in the bodies of adult residents from the village Kozhany in the Bryansk region, Russia, located on the shore of a drainless peat lake in an area subjected to significant radioactive contamination after the 1986 Chernobyl accident. The 137 Cs contents in lake water and fish were two orders of magnitude greater than in local rivers and flow-through lakes, 10 years after Chernobyl radioactive contamination, and remain stable. The 137 Cs content in lake fish and a mixture of forest mushrooms was between approximately 10-20 kBq/kg, which exceeded the temporary Russian permissible levels for these products by a factor of 20-40. Consumption of lake fish gave the main contribution to internal doses (40-50%) for Kozhany village inhabitants Simple countermeasures, such as Prussian blue doses for dairy cows and pre-boiling mushrooms and fish before cooking, halved the 137 Cs internal dose to inhabitants, even 10 years after the radioactive fallout

  4. Microbiology of Lonar Lake and other soda lakes

    Science.gov (United States)

    Paul Antony, Chakkiath; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-01-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence. PMID:23178675

  5. Habitat Evaluation Procedures (HEP) Report; Beaver Lake, Technical Report 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Entz, Ray

    2005-05-01

    On August 14, 2003, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the Beaver Lake property, an acquisition completed by the Kalispel Tribe of Indians in November 2002. Evaluation species and appropriate models include bald eagle, black-capped chickadee, Canada goose, mallard, muskrat, yellow warbler, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The Beaver Lake Project provides a total of 232.26 Habitat Units (HUs) for the species evaluated. Conifer forest habitat provides 136.58 HUs for bald eagle, black-capped chickadee, mallard, and white-tailed deer. Forested wetland habitat provides 20.02 HUs for bald eagle, black-caped chickadee, mallard, and white-tailed deer. Scrub-shrub wetland habitat provides 7.67 HUs for mallard, yellow warbler, and white-tailed deer. Grassland meadow provides 22.69 HUs for Canada goose and mallard. Emergent wetlands provide 35.04 HUs for Canada goose, mallard, and muskrat. Open water provided 10.26 HUs for Canada goose, mallard, and muskrat. The objective of using HEP at the Beaver Lake Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at future points in time so that the effect of management activities on wildlife habitat can be quantified. When combined with other tools, the baseline HEP will be used to determine the most effective on-site management, restoration, and enhancement actions to increase habitat suitability for targeted species. The same process will be replicated every five years to quantitatively evaluate the effectiveness of management strategies in improving and maintaining habitat conditions while providing additional crediting to BPA for enhanced habitat values.

  6. Fifty years of watershed research on the Fernow Experimental Forest, WV: effects of forest management and air pollution on hardwood forests

    Science.gov (United States)

    M.B. Adams; P.J. Edwards; J.N. Kochenderfer; F. Wood

    2004-01-01

    In 1951, stream gaging was begun on five small headwater catchments on the Fernow Experimental Forest in West Virginia, to study the effects of forest management activities, particularly timber harvesting, on water yield and quality. Results from these watersheds, and others gaged more recently, have shown that annual water yields increase in proportion to the basal...

  7. Hydrodynamic effects of reconnecting lake group with Yangtze River in China

    Directory of Open Access Journals (Sweden)

    Ling Kang

    2011-12-01

    Full Text Available The hydrodynamic effects of reconnecting a lake group with the Yangtze River were simulated using a three-dimensional hydrodynamic model. The model was calibrated and validated using the measured water temperature and total phosphorous. The circulation patterns, water temperature, and water exchange conditions between sub-lakes were simulated under two conditions: (1 the present condition, in which the lake group is isolated from the Yangtze River; and (2 the future condition, with a proposed improvement in which connecting the lake group with the Yangtze River will allow river water to be diverted into the lake group. The simulation period selected was characterized by extremely high temperature and very little rain. The results show that the cold inflow from the river has a significant effect on the water temperature only near the inlets, and the effect is more obvious in the lower water layers than that in the upper ones. The circulation pattern changes significantly and small-scale vortices only exist in part of the lake regions. The water exchange between sub-lakes is greatly enhanced with the proposed improvement. The water replacement rate increases with water diversion but varies in different sub-lakes. Finally, a new water diversion scheme was proposed to avoid contamination of some lakes in the early stage.

  8. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield

    Science.gov (United States)

    Mark C. Gabriel; Randy Kolka; Trent Wickman; Ed Nater; Laurel. Woodruff

    2009-01-01

    The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue...

  9. Global relationships between phosphorus and chlorophyll-a in oxbow lakes

    Science.gov (United States)

    Belcon, A. U.; Bernhardt, E. S.; Fritz, S. C.; Baker, P. A.

    2011-12-01

    Traditional limnological studies have focused on extant, large and deep bodies of fresh water. For over 70 years a strong positive relationship between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has been established in temperate lakes with phosphorus generally viewed as the most limiting factor to productivity (Deevey 1940, Schindler 1977). Over the last few decades however, investigations have expanded to include the examination of shallow lakes, particularly in terms of water quality, nutrient content and regime shifts between stable alternate states. Most of these studies, however, have focused on northern, high latitude regions where the lakes are typically postglacial, isolated and fed by small streams. Relatively little work has been done on oxbow lakes which are floodplain lakes and are semi or permanently connected to the river. Oxbow lakes have been shown to serve several important ecologic and economic functions including nurseries for young fish, feeding grounds for top aquatic predators and increasing the biodiversity of the landscape particularly in tropical regions of the world where high precipitation and large rivers have produced thousands of oxbow lakes. In many developing countries oxbow lakes are an important source of revenue through fishing. This study examined the relationship between nutrients and productivity in oxbow lakes globally through a wide-spread literature synthesis. Four hundred and twenty nine oxbow lakes were represented by 205 data points while 285 data points represented 156 non-floodplain lakes. Despite differences in latitude, lake size and climate we find that oxbow lakes globally have a significantly less steep slope in their TP/Chl relationship than non-floodplain lakes do indicating that the same amount of sestonic phosphorus results in lower productivity. Oxbow lakes (TP/Chl): r = 0.7676, slope = 0.7257, Non-floodplain lakes (TP/Chl): r = 0.8096, slope = 1.1309. We theorize that their connection to the

  10. Lava lake activity at the summit of Kīlauea Volcano in 2016

    Science.gov (United States)

    Patrick, Matthew R.; Orr, Tim R.; Swanson, Donald A.; Elias, Tamar; Shiro, Brian

    2018-04-10

    The ongoing summit eruption at Kīlauea Volcano, Hawai‘i, began in March 2008 with the formation of the Overlook crater, within Halema‘uma‘u Crater. As of late 2016, the Overlook crater contained a large, persistently active lava lake (250 × 190 meters). The accessibility of the lake allows frequent direct observations, and a robust geophysical monitoring network closely tracks subtle changes at the summit. These conditions present one of the best opportunities worldwide for understanding persistent lava lake behavior and the geophysical signals associated with open-vent basaltic eruptions. In this report, we provide a descriptive and visual summary of lava lake activity during 2016, a year consisting of continuous lava lake activity. The lake surface was composed of large black crustal plates separated by narrow incandescent spreading zones. The dominant motion of the surface was normally from north to south, but spattering produced transient disruptions to this steady motion. Spattering in the lake was common, consisting of one or more sites on the lake margin. The Overlook crater was continuously modified by the deposition of spatter (often as a thin veneer) on the crater walls, with frequent collapses of this adhered lava into the lake. Larger collapses, involving lithic material from the crater walls, triggered several small explosive events that deposited bombs and lapilli around the Halema‘uma‘u Crater rim, but these did not threaten public areas. The lava lake level varied over several tens of meters, controlled primarily by changes in summit magma reservoir pressure (in part driven by magma supply rates) and secondarily by fluctuations in spattering and gas release from the lake (commonly involving gas pistoning). The lake emitted a persistent gas plume, normally averaging 1,000–8,000 metric tons per day (t/d) of sulfur dioxide (SO2), as well as a constant fallout of small juvenile and lithic particles, including Pele’s hair and tears. The

  11. Fragmentation, topography, and forest age modulate impacts of drought on a tropical forested landscape in eastern Puerto Rico

    Science.gov (United States)

    Uriarte, M.; Schwartz, N.; Budsock, A.

    2017-12-01

    Naturally regenerating second-growth forests account for ca. 50% of tropical forest cover and provide key ecosystem services. Understanding climate impacts on these ecosystems is critical for developing effective mitigation programs. Differences in environmental conditions and landscape context from old-growth forests may exacerbate climate impacts on second-growth stands. Nearly 70% of forest regeneration is occurring in hilly, upland, or mountain regions; a large proportion of second-growth forests are also fragmented. The effects of drought at the landscape scale, however, and the factors that modulate landscape heterogeneity in drought impacts remain understudied. Heterogeneity in soil moisture, light, and temperature in fragmented, topographically complex landscapes is likely to influence climate impacts on these forests. We examine impacts of a severe drought in 2015 on a forested landscape in Puerto Rico using two anomalies in vegetation indices. The study landscape is fragmented and topographically complex and includes old- and second-growth forests. We consider how topography (slope, aspect), fragmentation (distance to forest edge, patch size), and forest age (old- vs second-growth) modulate landscape heterogeneity of drought impacts and recovery from drought. Drought impacts were more severe in second-growth forests than in old-growth stands. Both topography and forest fragmentation influences the magnitude of drought impacts. Forest growing in steep areas, south facing slopes, small patches, and closer to forest edges exhibited more marked responses to drought. Forest recovery from drought was greater in second-growth forests and south facing slopes but slower in small patches and closer to forest edges. These findings are congruent with studies of drought impacts on tree growth in the study region. Together these results demonstrate the need for a multi-scalar approach to the study of drought impacts on tropical forests.

  12. Modeling species’ realized climatic niche space and predicting their response to global warming for several western forest species with small geographic distributions

    Science.gov (United States)

    Marcus V. Warwell; Gerald E. Rehfeldt; Nicholas L. Crookston

    2010-01-01

    The Random Forests multiple regression tree was used to develop an empirically based bioclimatic model of the presence-absence of species occupying small geographic distributions in western North America. The species assessed were subalpine larch (Larix lyallii), smooth Arizona cypress (Cupressus arizonica ssp. glabra...

  13. Microhabitat of small mammals at ground and understorey levels in a deciduous, southern Atlantic forest.

    Science.gov (United States)

    Melo, Geruza L; Miotto, Barbara; Peres, Brisa; Cáceres, Nilton C

    2013-01-01

    Each animal species selects specific microhabitats for protection, foraging, or micro-climate. To understand the distribution patterns of small mammals on the ground and in the understorey, we investigated the use of microhabitats by small mammals in a deciduous forest of southern Brazil. Ten trap stations with seven capture points were used to sample the following microhabitats: liana, fallen log, ground litter, terrestrial ferns, simple-trunk tree, forked tree, and Piper sp. shrubs. Seven field phases were conducted, each for eight consecutive days, from September 2006 through January 2008. Four species of rodents (Akodon montensis, Sooretamys angouya, Oligoryzomys nigripes and Mus musculus) and two species of marsupials (Didelphis albiventris and Gracilinanus microtarsus) were captured. Captured species presented significant differences on their microhabitat use (ANOVA, p = 0.003), particularly between ground and understorey sites. Akodon montensis selected positively terrestrial ferns and trunks, S. angouya selected lianas, D. albiventris selected fallen trunks and Piper sp., and G. microtarsus choose tree trunks and lianas. We demonstrated that the local small-mammal assemblage does select microhabitats, with different types of associations between species and habitats. Besides, there is a strong evidence of habitat selection in order to diminish predation.

  14. Postdispersal seed predation and seed viability in forest soils: implications for the regeneration of tree species in Ethiopian church forests

    NARCIS (Netherlands)

    Wassie Eshete, A.; Bekele, T.; Sterck, F.J.; Teketay, D.; Bongers, F.

    2010-01-01

    Almost all dry Afromontane forests of Northern Ethiopia have been converted to agricultural, grazing or scrub lands except for small fragments left around churches ('Church forests'). Species regeneration in these forests is limited. We investigated (i) how intense postdispersal seed predation was

  15. Dendroclimatic signals deduced from riparian versus upland forest interior pines in North Karelia, Finland

    DEFF Research Database (Denmark)

    Helama, Samuli; Arentoft, Birgitte W.; Collin-Haubensak, Olivier

    2013-01-01

    Radial growth of boreal tree species is only rarely studied in riparian habitats. Here we investigated chronologies of earlywood, latewood, and annual ring widths and blue intensity (BI; a surrogate to latewood density) from riparian lake shore and upland forest interior pines (Pinus sylvestris L...

  16. Economic analysis of a small-sized combined heat and power plant using forest biomass in the Republic of Korea

    Science.gov (United States)

    Yeongwan Seo; Han-Sup Han; Edward M. (Ted) Bilek; Jungkee Choi; Dusong Cha; Jungsoo Lee

    2017-01-01

    Economic analysis was conducted on the feasibility of operating a small-sized (500kW/hour) gasification power plant producing heat and electricity in a rural town surrounded by forests in the Republic of Korea. Cost factors that were considered over the plant’s 20-year life included wood procurement, a wood grab loader, a chipper, a chip dryer, a gasifier, a generator...

  17. Response of lake chemistry to atmospheric deposition and climate in selected Class I wilderness areas in the western United States, 1993-2009

    Science.gov (United States)

    Mast, M. Alisa

    2011-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service, Air Resource Management, conducted a study to evaluate long-term trends in lake-water chemistry for 64 high-elevation lakes in selected Class I wilderness areas in Colorado, Idaho, Utah, and Wyoming during 1993 to 2009. Understanding how and why lake chemistry is changing in mountain areas is essential for effectively managing and protecting high-elevation aquatic ecosystems. Trends in emissions, atmospheric deposition, and climate variables (air temperature and precipitation amount) were evaluated over a similar period of record. A main objective of the study was to determine if changes in atmospheric deposition of contaminants in the Rocky Mountain region have resulted in measurable changes in the chemistry of high-elevation lakes. A second objective was to investigate linkages between lake chemistry and air temperature and precipitation to improve understanding of the sensitivity of mountain lakes to climate variability.

  18. High-resolution records detect human-caused changes to the boreal forest wildfire regime in interior Alaska

    Science.gov (United States)

    Gaglioti, Benjamin V.; Mann, Daniel H.; Jones, Benjamin M.; Wooller, Matthew J.; Finney, Bruce P.

    2016-01-01

    Stand-replacing wildfires are a keystone disturbance in the boreal forest, and they are becoming more common as the climate warms. Paleo-fire archives from the wildland–urban interface can quantify the prehistoric fire regime and assess how both human land-use and climate change impact ecosystem dynamics. Here, we use a combination of a sedimentary charcoal record preserved in varved lake sediments (annually layered) and fire scars in living trees to document changes in local fire return intervals (FRIs) and regional fire activity over the last 500 years. Ace Lake is within the boreal forest, located near the town of Fairbanks in interior Alaska, which was settled by gold miners in AD 1902. In the 400 years before settlement, fires occurred near the lake on average every 58 years. After settlement, fires became much more frequent (average every 18  years), and background charcoal flux rates rose to four times their preindustrial levels, indicating a region-wide increase in burning. Despite this surge in burning, the preindustrial boreal forest ecosystem and permafrost in the watershed have remained intact. Although fire suppression has reduced charcoal influx since the 1950s, an aging fuel load experiencing increasingly warm summers may pose management problems for this and other boreal sites that have similar land-use and fire histories. The large human-caused fire events that we identify can be used to test how increasingly common megafires may alter ecosystem dynamics in the future.

  19. Linking seasonal surface water dynamics with methane emissions and export from small, forested wetlands

    Science.gov (United States)

    Hondula, K. L.; Palmer, M.

    2017-12-01

    One of the biggest uncertainties about global methane sources and sinks is attributed to uncertainties regarding wetland area and its dynamics. This is exacerbated by confusion over the role of small, shallow water bodies like Delmarva bay wetlands that could be categorized as both wetlands and ponds. These small inland water bodies are often poorly quantified due to their size, closed forest canopies, and inter- and intra-annual variability in surface water extent. We are studying wetland-rich areas on the Delmarva Peninsula in the U.S. mid-Atlantic to address this uncertainty at the scale of individual wetland ecosystems ( 1m depth). We estimated the size and temporal variability of the methane emissions source area by combining these measurements with daily estimates of the extent of surface water inundation derived from water level monitoring and a high-resolution digital elevation model. This knowledge is critical for informing land use decisions (e.g. restoring wetlands specifically for climate mitigation), the jurisdiction of environmental policies in the US, and for resolving major outstanding discrepancies in our understanding of the global methane budget.

  20. Estimating actual evapotranspiration for forested sites: modifications to the Thornthwaite Model

    Science.gov (United States)

    Randall K. Kolka; Ann T. Wolf

    1998-01-01

    A previously coded version of the Thornthwaite water balance model was used to estimate annual actual evapotranspiration (AET) for 29 forested sites between 1900 and 1993 in the Upper Great Lakes area. Approximately 8 percent of the data sets calculated AET in error. Errors were detected in months when estimated AET was greater than potential evapotranspiration. Annual...

  1. Energy and water in the Great Lakes.

    Energy Technology Data Exchange (ETDEWEB)

    Tidwell, Vincent Carroll

    2011-11-01

    The nexus between thermoelectric power production and water use is not uniform across the U.S., but rather differs according to regional physiography, demography, power plant fleet composition, and the transmission network. That is, in some regions water demand for thermoelectric production is relatively small while in other regions it represents the dominate use. The later is the case for the Great Lakes region, which has important implications for the water resources and aquatic ecology of the Great Lakes watershed. This is today, but what about the future? Projected demographic trends, shifting lifestyles, and economic growth coupled with the threat of global climate change and mounting pressure for greater U.S. energy security could have profound effects on the region's energy future. Planning for such an uncertain future is further complicated by the fact that energy and environmental planning and regulatory decisionmaking is largely bifurcated in the region, with environmental and water resource concerns generally taken into account after new energy facilities and technologies have been proposed, or practices are already in place. Based on these confounding needs, the objective of this effort is to develop Great Lakes-specific methods and tools to integrate energy and water resource planning and thereby support the dual goals of smarter energy planning and development, and protection of Great Lakes water resources. Guiding policies for this planning are the Great Lakes and St. Lawrence River Basin Water Resources Compact and the Great Lakes Water Quality Agreement. The desired outcome of integrated energy-water-aquatic resource planning is a more sustainable regional energy mix for the Great Lakes basin ecosystem.

  2. Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

    Science.gov (United States)

    Placzek, Christa; Quade, Jay; Betancourt, Julio L.

    2001-09-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17° 22‧S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ∼2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16°S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes.

  3. Forest thinnings for integrated lumber and paper production

    Science.gov (United States)

    J.Y. Zhu; C.T. Scott; R. Gleisner; D. Mann; D.W. Vahey; D.P. Dykstra; G.H. Quinn; L.L. Edwards

    2007-01-01

    Integrated lumber and paper productions using forest thinning materials from U.S. national forests can significantly reduce the cost of prescriptive thinning operations. Many of the trees removed during forest thinnings are in small-diameter classes (diameter at breast height

  4. Environmental changes in the Tule Lake basin, Siskiyou and Modoc Counties, California, from 3 to 2 million years before present

    Science.gov (United States)

    Adam, David P.; Bradbury, J. Platt; Rieck, Hugh J.; Sarna-Wojcicki, Andrei M.

    1990-01-01

    Pollen and diatom analyses of a core from the town of Tulelake, Siskiyou County, California, for the period between 3 and 2 Ma reveal a paleoclimatic and paleolimnologic sequence recording a long, warm time interval that lasted from about 2.9 to 2.6 Ma and had a short, cooler interval within it. During this warm interval, the regional vegetation surrounding ancient Tule Lake was a mixed coniferous forest, and Tule Lake was a warm monomictic lake. Approximate modern analogs for this Pliocene fossil record at Tulelake are found at least 2 degrees farther south. The Tulelake warm interval appears to have correlatives in the North Atlantic oxygen isotope record and in the pollen record of the Reuverian in the Netherlands. An interval beginning at about 2.4 Ma was characterized at Tule Lake by slow sedimentation, by changes in the relative amounts of algae in the lake, and by an increase in the maximum percentages of Artemisia pollen.

  5. The diversity of benthic mollusks of Lake Victoria and Lake Burigi ...

    African Journals Online (AJOL)

    Molluscan diversity, abundance and distribution in sediments of Lake Victoria and its satellite lake, Lake Burigi, were investigated. The survey was carried out in January and February 2002 for Lake Victoria and in March and April 2002 for Lake Burigi. Ten genera were recorded from four zones of Lake Victoria while only ...

  6. Trace element composition in sediments of the Amazonian Lake Cristalino

    International Nuclear Information System (INIS)

    Ferraz, E.S.B.; Fernandes, E.A.N.

    1995-01-01

    Lake Cristalino is a small lake adjacent to the Negro River near Manaus and not far from the Amazonas River, in the central Amazon basin. The lake is fed seasonally by waters of the Negro River, a blackwater river with low levels of nutrients and suspended solids (7 g m -3 ). However, some investigations have established that Lake Cristalino has a high sedimentation rate (0.4-0.5 cm year -l ) similar to those in the alluvial floodplain lakes of the Amazonas River (suspended solids 200-300 g m -3 ). Sediment cores were taken during the low-water period and the trace-element composition and the natural radioactivity in the lake were examined. The results show a core (31 cm length) relatively uniform in concentrations of trace elements (Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Sc, Sm, Ta, Tb, Th, Yb and Zn), and the presence of 137 Cs in the first half. Concentrations of trace elements in Lake Cristalino sediments were not correlated with concentrations in the sediments of its parent river, the Negro River, or with concentrations in soils of the local area. However, significant correlation was found between the sediments of the lake and those of the Amazonas River. On the basis of these results, and water-level data at Manaus port, it is concluded that the lake occasionally receives variable amounts of sediment from the Amazonas River. 10 refs., 2 tabs., 2 figs

  7. Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  8. Lakes sensitivity to climatic stress – a sociological assessment

    Directory of Open Access Journals (Sweden)

    Lackowska Marta

    2016-12-01

    Full Text Available One of the conditions for effective water resources management in protected areas is local decision makers’ knowledge about potential threats caused by climate changes. Our study, conducted in the UNESCO Biosphere Reserve of Tuchola Forest in Poland, analyses the perception of threats by local stakeholders. Their assessments of the sensitivity of four lakes to the extreme weather events are compared with hydrological studies. The survey shows that the lakes’ varying responses to extreme weather conditions is rarely noticed by ordinary observers. Their perception is usually far from the hydrological facts, which indicates a lack of relevant information or a failure in making it widely accessible and understandable. Moreover, it is rather the human impact, not climate change, which is seen as the biggest threat to the lakes. Insufficient environmental knowledge may hinder the effective protection and management of natural resources, due to bad decisions and lack of the local communities’ support for adaptation and mitigation policies.

  9. Mite species (Acari: Mesostigmata new and rare to Polish fauna, inhabiting the soil of broadleaved forests dominated by small-leaved lime (Tilia cordata Mill. in Kwidzyn Forest District (N Poland

    Directory of Open Access Journals (Sweden)

    FALEŃCZYK-KOZIRÓG KATARZYNA

    2014-06-01

    Full Text Available During a two-year study on mites of the order Mesostigmata in broadleaved forest stands dominated by small-leaved lime (Tilia cordata Mill., 117 mite species were identified. Among them, 3 had been so far rarely recorded in Poland (Haemogamasus nidi, Stylochirus rovenensis and Eugamasus crassitarsis and 2 were classified as new to the Polish fauna (Veigaia sibirica and Digamasellus perpusillus.

  10. Monitoring of long-range transported air pollutants and precipitation. Monitoring programme for forest damage. Abstract of annual reports 1996; Overvaaking av langtransportert forurenset luft og nedboer. Overvaakingsprogram for skogskader. Sammendrag av aarsrapporter 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This report sums up the results for 1996 of two monitoring programmes: `` Norwegian Monitoring Programme for Long-Range Transported Air Pollutants`` and ``Norwegian forest monitoring programme``. The atmospheric pollution is monitored by measurements of chemical main components in the air and in precipitation. The effects of the pollutants on water quality are followed by monitoring of rivers, lakes and field research areas. The effects on fish are followed by regional investigations on benthic organisms, zooplankton and fish populations in rivers and lakes. Water chemical samples are taken each month from 16 rivers and acid material is monitored at seven field research areas. Samples are also taken from 200 lakes every autumn. The biological monitoring programme comprises fish in lakes and streams and benthic animals in lakes. The monitoring of forest damage uses three nation-wide areas from which registrations have been taken over a period of ten years. 28 figs., 6 tabs.

  11. Role of a productive lake in carbon sequestration within a calcareous catchment.

    Science.gov (United States)

    Nõges, Peeter; Cremona, Fabien; Laas, Alo; Martma, Tõnu; Rõõm, Eva-Ingrid; Toming, Kaire; Viik, Malle; Vilbaste, Sirje; Nõges, Tiina

    2016-04-15

    For a long time, lakes were considered unimportant in the global carbon (C) cycle because of their small total area compared to the ocean. Over the last two decades, a number of studies have highlighted the important role of lakes in both sequestering atmospheric C and modifying the C flux from the catchment by degassing CO2 and methane and burying calcite and organic matter in the sediment. Based on a full C mass balance, high frequency measurements of lake metabolism and stable isotope analysis of a large shallow eutrophic lake in Estonia, we assess the role alkaline lakes play in augmenting the strength of terrestrial carbonate weathering as a temporary CO2 sink. We show that a large part of organic C buried in the sediments in this type of lakes originates from the catchment although a direct uptake from the atmosphere during periods of intensive phytoplankton growth in eutrophic conditions contributes to the carbon sink. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. 75 FR 10456 - Kootenai National Forest, Fortine Ranger District, Montana; Galton Environmental Impact Statement

    Science.gov (United States)

    2010-03-08

    ...) Planning Areas (Wigwam, Grave, and Murphy) and the Fortine Ranger District portions of two (2) Planning... lawsuit settlement agreement with the Montana Wilderness Association commits the Forest Service to develop... travel planning for the Ten Lakes WSA. This project will also reduce hazardous fuels within and outside...

  13. Pervasive Rise of Small-scale Deforestation in Amazonia.

    Science.gov (United States)

    Kalamandeen, Michelle; Gloor, Emanuel; Mitchard, Edward; Quincey, Duncan; Ziv, Guy; Spracklen, Dominick; Spracklen, Benedict; Adami, Marcos; Aragão, Luiz E O C; Galbraith, David

    2018-01-25

    Understanding forest loss patterns in Amazonia, the Earth's largest rainforest region, is critical for effective forest conservation and management. Following the most detailed analysis to date, spanning the entire Amazon and extending over a 14-year period (2001-2014), we reveal significant shifts in deforestation dynamics of Amazonian forests. Firstly, hotspots of Amazonian forest loss are moving away from the southern Brazilian Amazon to Peru and Bolivia. Secondly, while the number of new large forest clearings (>50 ha) has declined significantly over time (46%), the number of new small clearings (<1 ha) increased by 34% between 2001-2007 and 2008-2014. Thirdly, we find that small-scale low-density forest loss expanded markedly in geographical extent during 2008-2014. This shift presents an important and alarming new challenge for forest conservation, despite reductions in overall deforestation rates.

  14. The value chain of small-sized energy wood

    Energy Technology Data Exchange (ETDEWEB)

    Karttunen, K.; Foehr, J.; Ranta, T. (Lappeenranta Univ. of Technology, Mikkeli (Finland), LUT Energy), Email: kalle.karttunen@lut.fi, Email: jarno.fohr@lut.fi, Email: tapio.ranta@lut.fi; Ahtikoski, A. (The Finnish Forest Research Institute, Rovaniemi (Finland)), Email: anssi.ahtikoski@metla.fi; Valsta, L. (Helsinki Univ. (Finland), Dept. of Forest Economics), Email: lauri.valsta@helsinki.fi

    2009-07-01

    Finland has agreed to increase the share of renewable energy to the level of 38% by the end of 2020. Most of the increase is to be based on bioenergy. According to the National Climate and Energy Strategy, the need for forest biomass will come to more than 20 TWh, or some 10 million cubic meters per year. Energy wood from young stand thinnings are the biomass resource with the most potential at the moment. The purpose of this study was to compare cost differences between forest management incorporating energy wood thinning and forest management based on traditional roundwood thinning. In addition, alternative supply chain costs for small-sized wood were studied. The results of the study show that it is worth considering the following points if the demand and average price for forest chips remain high. 1. Forest-owners: Forest management including energy wood thinning is financially feasible. 2. Supply chain: A terminal chipping chain enables large-scale procurement of small-sized energy wood. 3. Power plants: Currently, subsidies, emission trading, and decreasing pulpwood prices together enable large-scale use of small-sized wood for energy purposes. The value chain of small-sized energy wood in large-scale power plants could be mobilised. (orig.)

  15. Spatial and temporal genetic diversity of lake whitefish (Coregonus clupeaformis (Mitchill)) from Lake Huron and Lake Erie

    Science.gov (United States)

    Stott, Wendylee; Ebener, Mark P.; Mohr, Lloyd; Hartman, Travis; Johnson, Jim; Roseman, Edward F.

    2013-01-01

    Lake whitefish (Coregonus clupeaformis (Mitchill)) are important commercially, culturally, and ecologically in the Laurentian Great Lakes. Stocks of lake whitefish in the Great Lakes have recovered from low levels of abundance in the 1960s. Reductions in abundance, loss of habitat and environmental degradation can be accompanied by losses of genetic diversity and overall fitness that may persist even as populations recover demographically. Therefore, it is important to be able to identify stocks that have reduced levels of genetic diversity. In this study, we investigated patterns of genetic diversity at microsatellite DNA loci in lake whitefish collected between 1927 and 1929 (historical period) and between 1997 and 2005 (contemporary period) from Lake Huron and Lake Erie. Genetic analysis of lake whitefish from Lakes Huron and Erie shows that the amount of population structuring varies from lake to lake. Greater genetic divergences among collections from Lake Huron may be the result of sampling scale, migration patterns and demographic processes. Fluctuations in abundance of lake whitefish populations may have resulted in periods of increased genetic drift that have resulted in changes in allele frequencies over time, but periodic genetic drift was not severe enough to result in a significant loss of genetic diversity. Migration among stocks may have decreased levels of genetic differentiation while not completely obscuring stock boundaries. Recent changes in spatial boundaries to stocks, the number of stocks and life history characteristics of stocks further demonstrate the potential of coregonids for a swift and varied response to environmental change and emphasise the importance of incorporating both spatial and temporal considerations into management plans to ensure that diversity is preserved.

  16. Characterization of three acid strip mine lakes in Grundy County, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Master, W. A.

    1979-09-01

    Three small lakes with acid water and one with circumneutral water at an abandoned strip mine site were characterized to identify factors limiting biological productivity. Dissolved oxygen, specific conductance, and temperature profiles were determined. Water samples were analyzed for 23 parameters, and the lakes were examined for the presence of aquatic vascular plants and benthic inhabitants. The acid lakes ranged from 0.9 ha to 2.7 ha in surface area and from 3.1 m to 6.7 m in maximum depth. The mean pH of the acid lakes ranged from 3.1 to 3.9. Chemicals found at concentrations higher than Illinois surface water standards or federal criteria for the protection of aquatic life included Cd, Cu, Fe, Mn, SO/sub 4/=, and Zn. A number of these chemicals were at sufficiently high concentrations to limit the survival and productivity of most aquatic fauna. The lake with the poorest water quality had the least diversity of aquatic vascular plants and benthic invertebrates, while the circumneutral lake had the greatest diversity of species.

  17. High-levels of microplastic pollution in a large, remote, mountain lake

    International Nuclear Information System (INIS)

    Free, Christopher M.; Jensen, Olaf P.; Mason, Sherri A.; Eriksen, Marcus; Williamson, Nicholas J.; Boldgiv, Bazartseren

    2014-01-01

    Highlights: • We quantified pelagic microplastic pollution in Lake Hovsgol, Mongolia. • Lake Hovsgol is more polluted with microplastics than Lakes Huron and Superior. • Microplastics came from consumer goods; no microbeads/few pellets were observed. • Microplastics were sourced from population centers and distributed by the winds. • Without waste management, even small populations can heavily pollute large lakes. - Abstract: Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km −2 , Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics

  18. Price of forest chips decreasing

    International Nuclear Information System (INIS)

    Hakkila, P.

    2001-01-01

    Use of forest chips was studied in 1999 in the national Puuenergia (Wood Energy) research program. Wood combusting heating plants were questioned about are the main reasons restricting the increment of the use of forest chips. Heating plants, which did not use forest chips at all or which used less than 250 m 3 (625 bulk- m 3 ) in 1999 were excluded. The main restrictions for additional use of forest chips were: too high price of forest chips; lack of suppliers and/or uncertainty of deliveries; technical problems of reception and processing of forest chips; insufficiency of boiler output especially in winter; and unsatisfactory quality of chips. The price of forest chips becomes relatively high because wood biomass used for production of forest chips has to be collected from wide area. Heavy equipment has to be used even though small fragments of wood are processed, which increases the price of chips. It is essential for forest chips that the costs can be pressed down because competition with fossil fuels, peat and industrial wood residues is hard. Low market price leads to the situation in which forest owner gets no price of the raw material, the entrepreneurs operate at the limit of profitability and renovation of machinery is difficult, and forest chips suppliers have to sell the chips at prime costs. Price of forest chips has decreased significantly during the past decade. Nominal price of forest chips is now lower than two decades ago. The real price of chips has decreased even more than the nominal price, 35% during the past decade and 20% during the last five years. Chips, made of small diameter wood, are expensive because the price includes the felling costs and harvesting is carried out at thinning lots. Price is especially high if chips are made of delimbed small diameter wood due to increased the work and reduced amount of chips. The price of logging residue chips is most profitable because cutting does not cause additional costs. Recovery of chips is

  19. Diversity in the socio-economic role of the main non-wood forest products for the inhabitants of small villages and large towns in Poland

    OpenAIRE

    Barszcz, Anna; Suder, Alicja

    2009-01-01

    The NWFPs (non-wood forest products) sector is of the crucial importance to the Polish households but its social and economic role is varied and depends on place of residence. For the inhabitants of villages and small towns forests are the place of working and NWFPs sale provides an additional financial resource. City-dwellers do not treat NWFPs as a source of income but rather as an element of recreation and they use these products mainly for their own needs. Some remarks for the developing ...

  20. Distribution of tritium in a chronically contaminated lake

    International Nuclear Information System (INIS)

    Blaylock, B.G.; Frank, M.L.

    1978-01-01

    White Oak Lake located on the U.S. Department of Energy's Oak Ridge Reservation receives a continuous input of tritium from operating facilities and waste disposal operations at the Oak Ridge National Laboratory. The purpose of this paper was (1) to determine the distribution and concentration of tritium in an aquatic environment which has received releases of tritium significantly greater than expected releases from nuclear power plants, and (2) to determine the effect of fluctuating tritium concentrations in ambient water on the concentration of tritium in fish. Aquatic biota from White Oak Lake were analyzed for tissue water tritium and tissue bound tritium. Except for one plant species, the ratio of tissue water tritium to lake water tritium ranged from 0.80 to 1.02. The tissue water tritium in Gambusia affinis, the mosquito fish, followed closely the significant changes in tritium concentration in lake water. The turnover of tissue water tritium was very rapid; Gambusia from White Oak Lake eliminated 50% of their tissue water tritium in 14 min. The ratio of the specific activity of the tissue bound tritium to the specific activity of the lake water was greatest for the larger species of fish but never exceeded unity. The radiation dose to man from tritium which could be acquired through the aquatic food chain was relatively small when compared to other pathways. The whole body dose to a hypothetical individual taking in concentrations of tritium measured in White Oak Lake was 1.8 mrem/yr from eating fish and 10.0 mrem/yr from drinking water

  1. Nutrient cycling in Huntington Forest and Turkey Lakes deciduous stands: Nitrogen and sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, M J [State Univ. of New York, Syracuse, NY (USA); Foster, N W; Morrison, I K [Forestry Canada, Sault Ste. Marie, ON (Canada); Shepard, J P [National Council of the Paper Industry for Air and Stream Improvement, Gainsville, FL (USA)

    1992-01-01

    A study was conducted to analyze two tolerant hardwood forests that are exhibiting different levels of nitrate and sulfate leaching. Fluxes of N and S at the two sites were compared, and the fluxes of nitrate and sulfate through the forest canopy, forest floor, and mineral soil were determined in order to ascertain whether differences in these fluxes could be explained using information on the N, S, and C biogeochemistry of each site. One site is in the Adirondack region, where the impacts of acidic deposition have been noted; the other site is in central Ontario, and has geological, pedological, and hydrological characteristics that make it potentially sensitive to acidic deposition. An increase in concentration of sulfate and nitrate was noted after passage through the canopy at both sites. The Ontario site showed much greater leaching of nitrate. At the Adirondack site only, there was a marked increase in sulfate flux when water leached from the forest floor through the soil. The mineral soil was the largest pool of N and S for both sites. The Ontario soil had a C/N ratio of 16:1, narrower than the 34:1 ratio of the soil at the other site. The former ratio should favor accumulation of ammonium and nitrate ions, and subsequent nitrate leaching. Laboratory measurements suggest that the forest floor at the Ontario site may have higher N mineralization rates. Fluxes of N and S within the vegetation were generally similar at both sites. The higher nitrate leaching at the Ontario site may be attributed mostly to stand maturity coupled with tree mortality, but the absence of slow decomposing beech leaf litter and lower C/N ratio in the soil may also be contributing factors. 50 refs., 3 figs., 6 tabs.

  2. Composite materials from forest biomass : a review of current practices, science, and technology

    Science.gov (United States)

    Roger M. Rowell

    2007-01-01

    Renewable and sustainable composite materials can be produced using forest biomass if we maintain healthy forests. Small diameter trees and other forest biomass can be processed in the forest into small solid wood pieces, sliced veneers, strands, flakes, chips, particles and fiber that can be used to make construction composite products such as glued-laminated lumber,...

  3. The implications of new forest tenure reforms and forestry property markets for sustainable forest management and forest certification in China.

    Science.gov (United States)

    Chen, Juan; Innes, John L

    2013-11-15

    This study examines issues existing in the southern collective forests in China, particularly prior to the implementation of new forest tenure reforms, such as continued illegal logging and timber theft, inadequate availability of finance and inconsistent forest-related policies. Such problems are believed to be hindering the adoption of sustainable forest management (SFM) and forest certification by forest farmers in China. Two strategies were introduced by the Chinese government with the purpose of addressing these issues, namely forest tenure reforms and their associated supporting mechanism, forestry property markets. Through two case studies in southern China, we investigated the effectiveness of the two strategies as well as their implications for the adoption of SFM and forest certification. The two cases were Yong'an in Fujian province and Tonggu in Jiangxi province. Personal interviews with open-ended questions were conducted with small-scale forest farmers who had already benefited from the two strategies as well as market officers working for the two selected forestry property markets. The study identified eight issues constraining the potential adoption of SFM and certification in China, including limited finance, poorly developed infrastructure and transport systems, insecure forest tenures, inconsistent forest policies, low levels of awareness, illegal forest management practices, lack of local cooperative organizations, and inadequate knowledge and technical transfer. We found that the new forest tenure reforms and forestry property markets had generally fulfilled their original objectives and had the capacity to assist in addressing many of the issues facing forests prior to the reforms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Title: Water Quality Monitoring to Restore and Enhance Lake Herrick

    Science.gov (United States)

    Kannan, A.; Saintil, T.; Radcliffe, D. E.; Rasmussen, T. C.

    2017-12-01

    Lake Allyn M. Herrick is about 1.5 km2 and covers portions of the University of Georgia's East campus, the Oconee forest, residential and commercial land use. Lake Herrick, a 15-acre water body established in 1982 at the University of Georgia's campus was closed in 2002 for recreation due to fecal contamination, color change, and heavy sedimentation. Subsequent monitoring confirmed cyanobacterium blooms on the surface of lake and nutrient concentration especially phosphorus was one of the primary reasons. However, no studies have been done on lake inflows and outflows after 2005 in terms of nutrients and fecal Indicator bacteria. Two inflow tributaries and the outlet stream were monitored for discharge, E. coli, total coliform, forms of nitrogen and phosphorus and other water quality parameters during base flow and storm conditions. External environmental factors like precipitation, land-use/location, discharge, and internal factors within the water like temperature, DO, pH, conductivity, and turbidity influencing fecal indicator bacteria and nutrients will be discussed with data collected from the inflows/outflow between February 2016 to October 2017. Following this, microbial source tracking methods were also used to detect the bacterial source in the samples specific to a ruminant or human host. The source tracking data will be presented during the timeframe of January 2017 to September 2017, to draw a conclusion on the potential source of fecal contamination. The future aim of the project will include modeling flow and bacteria at the watershed scale in order to make management decisions to restore the lake for recreational uses where green infrastructure could play a key role.

  5. Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon

    Science.gov (United States)

    Bacon, Charles R.

    2008-01-01

    Crater Lake partly fills one of the most spectacular calderas of the world, an 8-by-10-km basin more than 1 km deep formed by collapse of the volcano known as Mount Mazama (fig. 1) during a rapid series of explosive eruptions about 7,700 years ago. Having a maximum depth of 594 m, Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 km2 of pristine forested and alpine terrain, including the lake itself, virtually all of Mount Mazama, and most of the area of the geologic map. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama's climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, greatly enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Lastly, the many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama are a source of information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive

  6. Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

    Science.gov (United States)

    Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

    2016-01-01

    Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

  7. Future Wildfire and Managed Fire Interactions in the Lake Tahoe Basin

    Science.gov (United States)

    Scheller, R.; Kretchun, A.

    2017-12-01

    Managing large forested landscape in the context of a changing climate and altered disturbance regimes presents new challenges and require integrated assessments of forest disturbance, management, succession, and the carbon cycle. Successful management under these circumstances will require information about trade-offs among multiple objectives and opportunities for spatially optimized landscape-scale management. Improved information about the effects of climate on forest communities, disturbance feedbacks, and the effectiveness of mitigation strategies enables actionable options for landscape managers. We evaluated the effects of fire suppression, wildfires, and forest fuel (thinning) treatments on the long-term carbon storage potential for Lake Tahoe Basin (LTB) forests under various climate futures. We simulated management scenarios that encompass fuel treatments across the larger landscape, beyond the Wildland Urban Interface. We improved upon current fire modeling under climate change via an integrated fire modeling module that, a) explicitly captures the influence of climate, fuels, topography, active fire management (e.g., fire suppression), and fuel treatments, and b) can be parameterized from available data, e.g., remote sensing, field reporting, fire databases, expert opinion. These improvements increase geographic flexibility and decrease reliance on broad historical fire regime statistics - imperfect targets for a no analog future and require minimal parameterization and calibration. We assessed the interactions among fuel treatments, prescribe fire, fire suppression, and stochastically recurring wildfires. Predicted changes in climate and ignition patterns in response to future climatic conditions, vegetation dynamics, and fuel treatments indicate larger potential long-term effects on C emissions, forest structure, and forest composition than prior studies.

  8. Regeneration response to tornado and salvage harvesting in a bottomland forest

    Science.gov (United States)

    John L. Nelson; John W. Groninger; Loretta L. Battaglia; Charles M. Ruffner

    2010-01-01

    A direct hit from an F4 tornado on May 2003, followed by a partial salvage logging operation at Mermet Lake State Conservation Area on the Ohio River bottoms of southern IL have provided a rare opportunity to assess the responses of a bottomland hardwood forest to severe wind and soil disturbances. The study area encompasses 700 acres and is representative of many...

  9. 77 FR 75186 - Notice of Closure, Target Shooting Public Safety Closure on the Lake Mountains in Utah County, UT

    Science.gov (United States)

    2012-12-19

    ... Land Management, Department of the Interior. ACTION: Notice of Closure. SUMMARY: The Bureau of Land... impacts is completed through the land use planning process. The Lake Mountains are a small mountain range... ridge. There are private residences along the lake shore. Utah Lake is a popular area for recreationists...

  10. Genome sequences of lower Great Lakes Microcystis sp. reveal strain-specific genes that are present and expressed in western Lake Erie blooms.

    Directory of Open Access Journals (Sweden)

    Kevin Anthony Meyer

    Full Text Available Blooms of the potentially toxic cyanobacterium Microcystis are increasing worldwide. In the Laurentian Great Lakes they pose major socioeconomic, ecological, and human health threats, particularly in western Lake Erie. However, the interpretation of "omics" data is constrained by the highly variable genome of Microcystis and the small number of reference genome sequences from strains isolated from the Great Lakes. To address this, we sequenced two Microcystis isolates from Lake Erie (Microcystis aeruginosa LE3 and M. wesenbergii LE013-01 and one from upstream Lake St. Clair (M. cf aeruginosa LSC13-02, and compared these data to the genomes of seventeen Microcystis spp. from across the globe as well as one metagenome and seven metatranscriptomes from a 2014 Lake Erie Microcystis bloom. For the publically available strains analyzed, the core genome is ~1900 genes, representing ~11% of total genes in the pan-genome and ~45% of each strain's genome. The flexible genome content was related to Microcystis subclades defined by phylogenetic analysis of both housekeeping genes and total core genes. To our knowledge this is the first evidence that the flexible genome is linked to the core genome of the Microcystis species complex. The majority of strain-specific genes were present and expressed in bloom communities in Lake Erie. Roughly 8% of these genes from the lower Great Lakes are involved in genome plasticity (rapid gain, loss, or rearrangement of genes and resistance to foreign genetic elements (such as CRISPR-Cas systems. Intriguingly, strain-specific genes from Microcystis cultured from around the world were also present and expressed in the Lake Erie blooms, suggesting that the Microcystis pangenome is truly global. The presence and expression of flexible genes, including strain-specific genes, suggests that strain-level genomic diversity may be important in maintaining Microcystis abundance during bloom events.

  11. Fine-scale acoustic telemetry reveals unexpected lake trout, Salvelinus namaycush, spawning habitats in northern Lake Huron, North America

    Science.gov (United States)

    Binder, Thomas; Farha, Steve A.; Thompson, Henry T.; Holbrook, Christopher; Bergstedt, Roger A.; Riley, Stephen; Bronte, Charles R.; He, Ji; Krueger, Charles C.

    2018-01-01

    Previous studies of lake trout, Salvelinus namaycush, spawning habitat in the Laurentian Great Lakes have used time- and labour-intensive survey methods and have focused on areas with historic observations of spawning aggregations and on habitats prejudged by researchers to be suitable for spawning. As an alternative, we used fine-scale acoustic telemetry to locate, describe and compare lake trout spawning habitats. Adult lake trout were implanted with acoustic transmitters and tracked during five consecutive spawning seasons in a 19–27 km2 region of the Drummond Island Refuge, Lake Huron, using the VEMCO Positioning System. Acoustic telemetry revealed discrete areas of aggregation on at least five reefs in the study area, subsequently confirmed by divers to contain deposited eggs. Notably, several identified spawning sites would likely not have been discovered using traditional methods because either they were too small and obscure to stand out on a bathymetric map or because they did not conform to the conceptual model of spawning habitat held by many biologists. Our most unique observation was egg deposition in gravel and rubble substrates located at the base of and beneath overhanging edges of large boulders. Spawning sites typically comprised <10% of the reef area and were used consistently over the 5-year study. Evaluation of habitat selection from the perspective of fish behaviour through use of acoustic transmitters offers potential to expand current conceptual models of critical spawning habitat.

  12. Reassuring livelihood functions of the forests to their dependents: Adoption of collaborative forest management system over Joint forest management regime in India

    Directory of Open Access Journals (Sweden)

    Narendra Kumar Bhatia

    2013-12-01

    Full Text Available With regard to forest management, rural livelihood, and poverty in India, it is often debated that JFM regime is not delivering livelihood functions of the forests to their dependents. This paper examines the state and scale of two decades old people-centric JFM system of India, and analyses the reasons with their indicators to shade off its shine in reducing povertyamong forest dependent people in several parts of the country. Paper also iscuss, how and to what extent, adoption of a multi-agency linked Collaborative Forest Management (CFM system could be a better strategy over JFM regime to reassure delivery of livelihood functions of the forests to their dependents in rural India. Arguments in this communication are intended to provide forest managers and policy-makers with necessary input to consider some location specific forest based entrepreneurial activities in CFM mode to provide a continuous source of small income to forest dependent people to ensure long lasting success of their forest management endeavours. Paper concludes with a recommendation to convert unviable JFM areas of India into a multiagency linked CFM system in a phased manner.

  13. Investigation of the complexity of streamflow fluctuations in a large heterogeneous lake catchment in China

    Science.gov (United States)

    Ye, Xuchun; Xu, Chong-Yu; Li, Xianghu; Zhang, Qi

    2018-05-01

    The occurrence of flood and drought frequency is highly correlated with the temporal fluctuations of streamflow series; understanding of these fluctuations is essential for the improved modeling and statistical prediction of extreme changes in river basins. In this study, the complexity of daily streamflow fluctuations was investigated by using multifractal detrended fluctuation analysis (MF-DFA) in a large heterogeneous lake basin, the Poyang Lake basin in China, and the potential impacts of human activities were also explored. Major results indicate that the multifractality of streamflow fluctuations shows significant regional characteristics. In the study catchment, all the daily streamflow series present a strong long-range correlation with Hurst exponents bigger than 0.8. The q-order Hurst exponent h( q) of all the hydrostations can be characterized well by only two parameters: a (0.354 ≤ a ≤ 0.384) and b (0.627 ≤ b ≤ 0.677), with no pronounced differences. Singularity spectrum analysis pointed out that small fluctuations play a dominant role in all daily streamflow series. Our research also revealed that both the correlation properties and the broad probability density function (PDF) of hydrological series can be responsible for the multifractality of streamflow series that depends on watershed areas. In addition, we emphasized the relationship between watershed area and the estimated multifractal parameters, such as the Hurst exponent and fitted parameters a and b from the q-order Hurst exponent h( q). However, the relationship between the width of the singularity spectrum (Δ α) and watershed area is not clear. Further investigation revealed that increasing forest coverage and reservoir storage can effectively enhance the persistence of daily streamflow, decrease the hydrological complexity of large fluctuations, and increase the small fluctuations.

  14. Assessment of Land-Cover/Land-Use Change and Landscape Patterns in the Two National Nature Reserves of Ebinur Lake Watershed, Xinjiang, China

    Directory of Open Access Journals (Sweden)

    Fei Zhang

    2017-05-01

    Full Text Available Land-cover and land-use change (LCLUC alters landscape patterns and affects regional ecosystems. The objective of this study was to examine LCLUC and landscape patterns in Ebinur Lake Wetland National Nature Reserve (ELWNNR and Ganjia Lake Haloxylon Forest National Nature Reserve (GLHFNNR, two biodiversity-rich national nature reserves in the Ebinur Lake Watershed (ELW, Xinjiang, China. Landsat satellite images from 1972, 1998, 2007 and 2013 were used to calculate the dynamics of a land-cover and land-use (LCLU transition matrix and landscape pattern index using ENVI 5.1 and FRAGSTATS 3.3. The results showed drastic land use modifications have occurred in ELWNNR during the past four decades. Between 1972 and 1998, 1998 and 2007, and 2007 and 2013, approximately 251.50 km2 (7.93%, 122.70 km2 (3.87%, and 195.40 km2 (6.16% of wetland were turned into salinized land. In GLHFNNR both low and medium density Haloxylon forest area declined while high density Haloxylon forest area increased. This contribution presents a method for characterizing LCLUC using one or more cross-tabulation matrices based on Sankey diagrams, demonstrating the depiction of flows of energy or materials through ecosystem network. The ecological landscape index displayed that a unique landscape patches have shrunk in size, scattered, and fragmented. It becomes a more diverse landscape. Human activities like farming were negatively correlated with the landscape diversity of wetlands. Furthermore, evidence of degraded wetlands caused by air temperature and annual precipitation, was also observed. We conclude that national and regional policies related to agriculture and water use have significantly contributed to the extensive changes; the ELWNNR and GLHFNNR are highly susceptible to LCLUC in the surrounding Ebinur Lake Watershed.

  15. A pollen-based record of late glacial-Holocene climatic variability in the southern lake district, Chile

    NARCIS (Netherlands)

    Vargas-Ramirez, L.; Roche, E.; Gerrienne, P.; Hooghiemstra, H.

    2008-01-01

    A pollen record from Puyehue area (40°S; 72°W) in the southern Lake District, Chile, indicates that prior to 13,410 14C yr BP (ca. 16,500-15,200 cal yr BP), cold resistant and hygrophilous vegetation, particularly Nothofagus forest and myricaceous vegetation, covered the area. From ca. 15,000 cal yr

  16. Anaerobic halo- alkaliphilic bacterial community of athalassic, hypersaline Mono lake and Owens Lake in California

    Science.gov (United States)

    Pikuta, Elena V.; Detkova, Ekaterina N.; Bej, Asim K.; Marsic, Damien; Hoover, Richard B.

    2003-02-01

    The bacterial diversity of microbial extremophiles from the meromictic, hypersaline Mono Lake and a small evaporite pool in Owens Lake of California was studied. In spite of these regions had differing mineral background and different concentrations of NaCl in water they contain the same halo- alkaliphiles anaerobic bacterial community. Three new species of bacteria were detected in this community: primary anaerobe, dissipotrophic saccharolytic spirochete Spirochaeta americana strain AspG1T, primary anaerobe which is proteolytic Tindallia californiensis strain APOT, and secondary anaerobe, hydrogen using Desulfonatronum thiodismutans strain MLF1T, which is sulfate- reducer with chemo-litho-autotrophic metabolism. All of these bacteria are obligate alkaliphiles and dependent upon Na+ ions and CO32- ions in growth mediums. It is interesting that closest relationships for two of these species were isolates from samples of equatorial African soda Magadi lake: Spirochaeta americana AspG1T has 99.4% similarity on 16S rDNA- analyses with Spirochaeta alkalica Z- 7491T, and Tindallia californiensis APOT has 99.1% similarity with Tindallia magadiensis Z-7934T. But result of DNA-DNA- hybridization demonstrated less then 50% similarity between Spirochaeta americana AspG1T and Spirochaeta alkalica Z-7491T. Percent of homology between Tindallia californiensis APOT and Tindallia magadiensis Z-7934T is only 55%. The sulfate-reducer from the alkalic anaerobic community of Magadi lake Desulfonatronovibrio hydrogenovorans Z-7935T was phylogenetically distant from this sulfate-reducer in Mono lake, but genetically closer (99.7% similarity) to the sulfate-reducer, isolated from Central Asian alkalic lake Khadyn in Siberia Desulfonatronum lacustre Z-7951T. The study of key enzymes (hydrogenase and CO- hydrogenase) in Tindallia californiensis APOT and Desulfonatronum thiodismutans MLF1T showed the presence of high activity of both the enzymes in first and only hydrogenase in second

  17. Characterization of suspended solids and total phosphorus loadings from small watersheds in Wisconsin

    Science.gov (United States)

    Danz, Mari E.; Corsi, Steven R.; Graczyk, David J.; Bannerman, Roger T.

    2010-01-01

    Knowledge of the daily, monthly, and yearly distribution of contaminant loadings and streamflow can be critical for the successful implementation and evaluation of water-quality management practices. Loading data for solids (suspended sediment and total suspended solids) and total phosphorus and streamflow data for 23 watersheds were summarized for four ecoregions of Wisconsin: the Driftless Area Ecoregion, the Northern Lakes and Forests Ecoregion, the North Central Hardwoods Ecoregion, and the Southeastern Wisconsin Till Plains Ecoregion. The Northern Lakes and Forests and the North Central Hardwoods Ecoregions were combined into one region for analysis due to a lack of sufficient data in each region. Urban watersheds, all located in the Southeastern Wisconsin Till Plains, were analyzed separately from rural watersheds as the Rural Southeastern Wisconsin Till Plains region and the Urban Southeastern Wisconsin Till Plains region. Results provide information on the distribution of loadings and streamflow between base flow and stormflow, the timing of loadings and streamflow throughout the year, and information regarding the number of days in which the majority of the annual loading is transported. The average contribution to annual solids loading from stormflow periods for the Driftless Area Ecoregion was 84 percent, the Northern Lakes and Forests/North Central Hardwoods region was 71 percent, the Rural Southeastern Wisconsin Till Plains region was 70 percent, and the Urban Southeastern Wisconsin Till Plains region was 90 percent. The average contributions to annual total phosphorus loading from stormflow periods were 72, 49, 61, and 76 percent for each of the respective regions. The average contributions to annual streamflow from stormflow periods are 20, 23, 31, and 50 percent for each of the respective regions. In all regions, the most substantial loading contributions for solids were in the late winter (February through March), spring (April through May), and

  18. Depth as an organizer of fish assemblages in floodplain lakes

    Science.gov (United States)

    Miranda, L.E.

    2011-01-01

    Depth reduction is a natural process in floodplain lakes, but in many basins has been accelerated by anthropogenic disturbances. A diverse set of 42 floodplain lakes in the Yazoo River Basin (Mississippi, USA) was examined to test the hypothesis of whether depth reduction was a key determinant of water quality and fish assemblage structure. Single and multiple variable analyses were applied to 10 commonly monitored water variables and 54 fish species. Results showed strong associations between depth and water characteristics, and between depth and fish assemblages. Deep lakes provided less variable environments, clearer water, and a wider range of microhabitats than shallow lakes. The greater environmental stability was reflected by the dominant species in the assemblages, which included a broader representation of large-body species, species less tolerant of extreme water quality, and more predators. Stability in deep lakes was further reflected by reduced among-lake variability in taxa representation. Fish assemblages in shallow lakes were more variable than deep lakes, and commonly dominated by opportunistic species that have early maturity, extended breeding seasons, small adult size, and short lifespan. Depth is a causal factor that drives many physical and chemical variables that contribute to organizing fish assemblages in floodplain lakes. Thus, correlations between fish and water transparency, temperature, oxygen, trophic state, habitat structure, and other environmental descriptors may ultimately be totally or partly regulated by depth. In basins undergoing rapid anthropogenic modifications, local changes forced by depth reductions may be expected to eliminate species available from the regional pool and could have considerable ecological implications. ?? 2010 Springer Basel AG (outside the USA).

  19. Managing A Lake/Aquifer System-Science, Policy, and the Public Interest

    Science.gov (United States)

    Shaver, R. B.

    2009-12-01

    Lake Isabel is a small (312 ha) natural lake located in central North Dakota in the glaciated Missouri Coteau. The average lake depth is about 1.8 m with a maximum depth of about 3.6 to 4.6 m. The lake overlies the Central Dakota aquifer complex which is comprised of three sand and gravel aquifer units that are either directly or indirectly (through leakage) hydraulically connected to the lake. The aquifer is a major water source for center pivot irrigation. During the 2001-2008 drought, lower lake levels reduced lake recreation, including leaving many boat docks unusable. Lake homeowners attribute lake level decline to irrigation pumping and believe that irrigation should be curtailed. There is no water right associated with Lake Isabel because there are no constructed works associated with the lake. Therefore, under North Dakota statute the lake cannot be protected as a prior (senior) appropriator. The lake does have standing under the public interest as defined by North Dakota statute. Evaluation of the public interest involves the integration of both science and policy. Is it in the best interest of the people of the state to prohibit ground water withdrawals for irrigation to protect the lake? This is a policy decision, not a scientific decision. The basis of the policy decision should include an economic analysis of the irrigated crops, fish, wildlife, recreation, and lake property. In addition, priority of use and lake level history should be considered. The issue can likely be resolved without scientific controversy arising from hydrologic system uncertainty. If the decision is to protect the lake at some level, the issue becomes “scientized” and the following questions need to be answered: 1) Does irrigation pumping effect changes in lake levels? 2) Is our level of scientific understanding sufficient to determine what volume of irrigation pumping will cause what amount of lake level change? 3) Given aquifer lag time response to changes in pumping and

  20. Hazards of volcanic lakes: analysis of Lakes Quilotoa and Cuicocha, Ecuador

    Directory of Open Access Journals (Sweden)

    G. Gunkel

    2008-01-01

    Full Text Available Volcanic lakes within calderas should be viewed as high-risk systems, and an intensive lake monitoring must be carried out to evaluate the hazard of potential limnic or phreatic-magmatic eruptions. In Ecuador, two caldera lakesLakes Quilotoa and Cuicocha, located in the high Andean region >3000 a.s.l. – have been the focus of these investigations. Both volcanoes are geologically young or historically active, and have formed large and deep calderas with lakes of 2 to 3 km in diameter, and 248 and 148 m in depth, respectively. In both lakes, visible gas emissions of CO2 occur, and an accumulation of CO2 in the deep water body must be taken into account.

    Investigations were carried out to evaluate the hazards of these volcanic lakes, and in Lake Cuicocha intensive monitoring was carried out for the evaluation of possible renewed volcanic activities. At Lake Quilotoa, a limnic eruption and diffuse CO2 degassing at the lake surface are to be expected, while at Lake Cuicocha, an increased risk of a phreatic-magmatic eruption exists.