Historical fire and multidecadal drought as context for piñon - Juniper woodland restoration in western Colorado

Science.gov (United States)

Shinneman, Douglas J.; Baker, William L.

2009-01-01

Fire is known to structure tree populations, but the role of broad-scale climate variability is less clear. For example, the influence of climatic “teleconnections” (the relationship between oceanic–atmospheric fluctuations and anomalous weather patterns across broad scales) on forest age structure is relatively unexplored. We sampled semiarid piñon–juniper (Pinus edulis–Juniperus osteosperma) woodlands in western Colorado, USA, to test the hypothesis that woodland age structures are shaped by climate, including links to oceanic–atmospheric fluctuations, and by past fires and livestock grazing. Low-severity surface fire was lacking, as fire scars were absent, and did not influence woodland densities, but stand-replacing fires served as long-rotation (>400–600 years), stand-initiating events. Old-growth stands (>300 years old) were found in 75% of plots, consistent with a long fire rotation. Juniper and piñon age structures suggest contrasting responses during the past several centuries to dry and wet episodes linked to the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO). Juniper density increased slightly during periods of drought, positive (warm) AMO (after ∼10-year lag), and negative (cool) PDO. In contrast, piñon populations may still be recovering from a long, drought-filled period (AD 1620–1820), with pulses of recovery favored during cool AMO, warm PDO, and above-average moisture periods. Analysis of 20th-century tree establishment and instrumental climate data corroborate the long-term relationships between age structure and climate. After Euro–American settlement (AD 1881), livestock grazing reduced understory grasses and forbs, reducing competition with tree seedlings and facilitating climate-induced increases in piñons. Thus tree populations in these woodlands are in flux, affected by drought and wet periods linked to oceanic–atmospheric variability, Euro–American livestock grazing, and long

TAP Report - Southwest Idaho Juniper Working Group

Energy Technology Data Exchange (ETDEWEB)

Gresham, Garold Linn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

There is explicit need for characterization of the materials for possible commercialization as little characterization data exists. Pinyon-juniper woodlands are a major ecosystem type found in the Southwest and the Intermountain West regions of the United States including Nevada, Idaho and Oregon. These widespread ecosystems are characterized by the presence of several different species of pinyon and juniper as the dominant plant cover. Since the 1800s, pinyon-juniper woodlands have rapidly expanded their range at the expense of existing ecosystems. Additionally, existing woodlands have become denser, progressively creating potential fire hazards as seen in the Soda Fire, which burned more than 400 sq. miles. Land managers responsible for these areas often desire to reduce pinyon-juniper coverage on their lands for a variety of reasons, as stated in the Working Group objectives. However, the cost of clearing thinning pinyon-juniper stands can be prohibitive. One reason for this is the lack of utilization options for the resulting biomass that could help recover some of the cost of pinyon-juniper stand management. The goal of this TAP effort was to assess the feedstock characteristics of biomass from a juniper harvested from Owyhee County to evaluate possible fuel and conversion utilization options.

Assessing Pinyon Juniper Feedstock Properties and Utilization Options

Energy Technology Data Exchange (ETDEWEB)

Gresham, Garold Linn [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kenney, Kevin Louis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-08-01

Pinyon-juniper woodlands are a major ecosystem type found in the Southwest and the Intermountain West regions of the United States. These ecosystems are characterized by the presence of several different species of pinyon pine and juniper as the dominant plant cover. Since the 1800s, pinyon-juniper woodlands have rapidly expanded their range at the expense of existing ecosystems. Additionally, existing woodlands have become more dense, potentially increasing fire hazards. Land managers responsible for these areas often desire to reduce pinyonjuniper coverage on their lands for a variety of reasons, including restoration to previous vegetative cover, mitigation of fire risk, and improvement in wildlife habitat. However, the cost of clearing or thinning pinyon-juniper stands can be prohibitive. One reason for this is the lack of utilization options for the resulting biomass that could help recover some of the cost of pinyonjuniper stand management. The goal of this project was to assess the feedstock characteristics of biomass from a pinyon-juniper harvest so that potential applications for the biomass may be evaluated.

Detecting mortality induced structural and functional changes in a pinon-juniper woodland using Landsat and RapidEye time series

Science.gov (United States)

Dan J. Krofcheck; Jan U. H. Eitel; Lee A. Vierling; Urs Schulthess; Timothy M. Hilton; Eva Dettweiler-Robinson; Rosemary Pendleton; Marcy E. Litvak

2014-01-01

Pinon-juniper (PJ) woodlands have recently undergone dramatic drought-induced mortality, triggering broad scale structural changes in this extensive Southwestern US biome. Given that climate projections for the region suggest widespread conifer mortality is likely to continue into the next century, it is critical to better understand how this climate-induced change in...

Hydraulic limits preceding mortality in a piñon-juniper woodland under experimental drought.

Science.gov (United States)

Plaut, Jennifer A; Yepez, Enrico A; Hill, Judson; Pangle, Robert; Sperry, John S; Pockman, William T; McDowell, Nate G

2012-09-01

Drought-related tree mortality occurs globally and may increase in the future, but we lack sufficient mechanistic understanding to accurately predict it. Here we present the first field assessment of the physiological mechanisms leading to mortality in an ecosystem-scale rainfall manipulation of a piñon-juniper (Pinus edulis-Juniperus monosperma) woodland. We measured transpiration (E) and modelled the transpiration rate initiating hydraulic failure (E(crit) ). We predicted that isohydric piñon would experience mortality after prolonged periods of severely limited gas exchange as required to avoid hydraulic failure; anisohydric juniper would also avoid hydraulic failure, but sustain gas exchange due to its greater cavitation resistance. After 1 year of treatment, 67% of droughted mature piñon died with concomitant infestation by bark beetles (Ips confusus) and bluestain fungus (Ophiostoma spp.); no mortality occurred in juniper or in control piñon. As predicted, both species avoided hydraulic failure, but safety margins from E(crit) were much smaller in piñon, especially droughted piñon, which also experienced chronically low hydraulic conductance. The defining characteristic of trees that died was a 7 month period of near-zero gas exchange, versus 2 months for surviving piñon. Hydraulic limits to gas exchange, not hydraulic failure per se, promoted drought-related mortality in piñon pine. © 2012 Blackwell Publishing Ltd.

Effects of thinning, burning, seeding, and slash arrangements on understory communities in pinyon-juniper woodlands of northern Arizona

Directory of Open Access Journals (Sweden)

Maria Irwin

2011-11-01

Full Text Available Pinyon-juniper woodlands are a dominant ecosystem in the American Southwest that have been increasing in density over the last century, generating concerns about the effects on wildlife habitat, livestock forage, and wildfire risk. We tested 16 treatment combinations designed to restore stands to historic conditions by examining the impact on understory plant richness and abundance. We thinned three sites comprised of different parent soil materials: limestone, sandstone, and basalt. Each site had one of four slash arrangements: piled, broadcast, clustered, or no thinning. Each of these arrangements received a different burning/seeding treatment: prescribed fire, seeding, prescribed fire and seeding, or none. This study corresponded with the driest period in the last 55 years, and plant species richness decreased by an average of 40% from the previous year in the control plots. Richness was significantly different due to slash arrangement at the basalt site only. Burning or seeding did not affect richness at any of the sites. Plant species abundance was generally low and not influenced by treatment or site. This study demonstrates that extensive ecosystem manipulation in the pinyon-juniper woodlands of northern Arizona did not affect understory richness or abundance the first year after treatment during a drought.

Effects of thinning, burning, seeding, and slash arrangements on understory communities in pinyon-juniper woodlands of northern Arizona

Directory of Open Access Journals (Sweden)

Maria R. Irwin

2011-06-01

Full Text Available Pinyon-juniper woodlands are a dominant ecosystem in the American Southwest that have been increasing in density over the last century, generating concerns about the effects on wildlife habitat, livestock forage, and wildfire risk. We tested 16 treatment combinations designed to restore stands to historic conditions by examining the impact on understory plant richness and abundance. We thinned three sites comprised of different parent soil materials: limestone, sandstone, and basalt. Each site had one of four slash arrangements: piled, broadcast, clustered, or no thinning. Each of these arrangements received a different burning/seeding treatment: prescribed fire, seeding, prescribed fire and seeding, or none. This study corresponded with the driest period in the last 55 years, and plant species richness decreased by an average of 40% from the previous year in the control plots. Richness was significantly different due to slash arrangement at the basalt site only. Burning or seeding did not affect richness at any of the sites. Plant species abundance was generally low and not influenced by treatment or site. This study demonstrates that extensive ecosystem manipulation in the pinyon-juniper woodlands of northern Arizona did not affect understory richness or abundance the first year after treatment during a drought.

Limits to understory plant restoration following fuel-reduction treatments in a piñon-juniper woodland.

Science.gov (United States)

Redmond, Miranda D; Zelikova, Tamara J; Barger, Nichole N

2014-11-01

National fuel-reduction programs aim to reduce the risk of wildland fires to human communities and to restore forest and rangeland ecosystems to resemble their historical structure, function, and diversity. There are a number of factors, such as seed bank dynamics, post-treatment climate, and herbivory, which determine whether this latter goal may be achieved. Here, we examine the short-term (2 years) vegetation response to fuel-reduction treatments (mechanical mastication, broadcast burn, and pile burn) and seeding of native grasses on understory vegetation in an upland piñon-juniper woodland in southeast Utah. We also examine how wildlife herbivory affects the success of fuel-reduction treatments. Herbaceous cover increased in response to fuel-reduction treatments in all seeded treatments, with the broadcast burn and mastication having greater increases (234 and 160 %, respectively) in herbaceous cover than the pile burn (32 %). In the absence of seeding, herbaceous cover only increased in the broadcast burn (32 %). Notably, fuel-reduction treatments, but not seeding, strongly affected herbaceous plant composition. All fuel-reduction treatments increased the relative density of invasive species, especially in the broadcast burn, which shifted the plant community composition from one dominated by perennial graminoids to one dominated by annual forbs. Herbivory by wildlife reduced understory plant cover by over 40 % and altered plant community composition. If the primary management goal is to enhance understory cover while promoting native species abundance, our study suggests that mastication may be the most effective treatment strategy in these upland piñon-juniper woodlands. Seed applications and wildlife exclosures further enhanced herbaceous cover following fuel-reduction treatments.

Plant establishment and soil microenvironments in Utah juniper masticated woodlands

Science.gov (United States)

Kert R. Young

2012-01-01

Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after...

Final report: Hydraulic mechanisms of survival and mortality during drought in pinon-juniper woodlands of southwestern USA

Energy Technology Data Exchange (ETDEWEB)

Pockman, William [Univ. of New Mexico, Albuquerque, NM (United States)

2016-11-23

The goal of this project was to use rainfall manipulation of an intact pinon-juniper woodland in central New Mexico to understand the mechanisms that control the response of these species to extremes of rainfall. Experimental plots were installed in a pinon-juniper woodland at the Sevilleta National Wildlife Refuge and treatments were imposed in August 2007. Treatments consisted of 1) a Drought treatment imposed by diverting approximately 45% of precipitation away from the plot, 2) and Irrigation treatment imposed by applying six 19 mm simulated rainfall events at regular intervals during the growing season, 3) a Cover Control treatment designed to assess the impact of the plastic troughs constructed on Drought plots without imposing the rainfall diversion, and 4) an untreated control that received no modification. Extensive pinon mortality was observed beginning one year after the start of drought treatment on hillslope plots, while a third drought plot on deeper soils did not exhibit pinon mortality until the fifth year of drought treatment. Pinon mortality occurred in the context of high levels of bark beetle activity, motivating the installation of two additional plots in 2010: a control plot and a drought plot built to the same standards as the original treatments but with bark beetle control maintained by pesticide application to the bole of target trees from 2010 - 2016. Although the drought treatment created similar conditions to those experienced on hillslope drought plots, the drought plot with bark beetle control exhibited no pinon mortality for 5 years even in the presence of high regional bark beetle activity in 2012/13. One of the goals of the research was to identify the mechanism of drought-induced mortality in pinon and juniper: 1) mortality due to catastrophic failure of water transport through plant tissues (hydraulic failure), 2) mortality due to limitations in carbon uptake (carbon starvation) and 3) either of the first two mechanisms with the

The effects of drought-induced mortality on the response of surviving trees in piñon-juniper woodlands

Science.gov (United States)

Huang, C. W.; Pockman, W.; Litvak, M. E.

2017-12-01

lthough it is well-established that land cover change influences water and carbon cycles across different spatiotemporal scales, the impact of climate-driven mortality events on site energy and water balance and subsequently on vegetation dynamics is more variable among studies. In semi-arid ecosystems globally, mortality events following severe drought are increasingly common. We used long-term observations (i.e., from 2009 to present) in two piñon-juniper (i.e., Pinus edulis and Juniperus monosperma) woodlands located at central New Mexico USA to explore the consequence of mortality events in such water-stressed environments. We compared a pinon-juniper woodland site where girdling was used to mimic mortality of adult pinon (PJG) with a nearby untreated woodland site (PJC). Our primary goal is to disentangle the reduction in water loss via biological pathway (i.e., leaf and sapwood area) introduced by girdling manipulation from other effects contributing to the response of surviving trees such as modifications in surface reflectivity (i.e., albedo and emissivity) and surface roughness impacting the partitioning between components in both energy and water balance at canopy level. To achieve this goal, we directly measured sap flux, environmental factors and ecosystem-atmosphere exchange of carbon, water and energy fluxes using eddy-covariance systems at both sites. We found that 1) for each component of the energy balance the difference between PJC and PJG was surprisingly negligible such that the canopy-level surface temperature (i.e., both radiometric and aerodynamic temperature) remains nearly identical for the two sites; 2) the surface reflectivity and roughness are mainly dominated by the soil surface especially when the foliage coverage in semi-arid regions is small; 3) the increase in soil evaporation after girdling manipulation outcompetes the surviving trees for the use of water in the soil. These results suggest that the so-called `water release

Pinon and juniper field guide: Asking the right questions to select appropriate management actions

Science.gov (United States)

R. J. Tausch; R. F. Miller; B. A. Roundy; J. C. Chambers

2009-01-01

Pinon-juniper woodlands are an important vegetation type in the Great Basin. Old-growth and open shrub savanna woodlands have been present over much of the last several hundred years. Strong evidence indicates these woodlands have experienced significant tree infilling and major expansion in their distribution since the late 1800s by encroaching into surrounding...

Frijolito Watershed: Integrated investigations of a rapidly eroding pinyon-juniper hillslope

International Nuclear Information System (INIS)

Wilcox, B.P.; Pitlick, J.

1995-01-01

The dramatic acceleration of erosion associated with the expansion of pinyon-juniper woodlands over the past 100 years has been widely recognized, but few process-based studies of this phenomenon have been undertaken. In an attempt to identify the underlying causes, and the factors that affect erosion processes, we have initiated an interdisciplinary study of a rapidly eroding pinyon-juniper woodland in northern New Mexico. Since July 1993, we have collected data on runoff, erosion, and weather conditions from a 1-ha catchment study area and have conducted surveys of topography, soils, and vegetation. Our preliminary results indicate that although runoff makes up less than 10% of the annual water budget, runoff events - which are frequent in the summer - are capable of moving large amounts of sediment. We estimate that between July 1993 and October 1994, between 25,000 and 50,000 kg of sediment has eroded and been transported from the catchment. The information gained from such studies is essential to our ability to formulate effective strategies for managing these rapidly eroding woodlands

Repeat, Low Altitude Measurements of Vegetation Status and Biomass Using Manned Aerial and UAS Imagery in a Piñon-Juniper Woodland

Science.gov (United States)

Krofcheck, D. J.; Lippitt, C.; Loerch, A.; Litvak, M. E.

2015-12-01

Measuring the above ground biomass of vegetation is a critical component of any ecological monitoring campaign. Traditionally, biomass of vegetation was measured with allometric-based approach. However, it is also time-consuming, labor-intensive, and extremely expensive to conduct over large scales and consequently is cost-prohibitive at the landscape scale. Furthermore, in semi-arid ecosystems characterized by vegetation with inconsistent growth morphologies (e.g., piñon-juniper woodlands), even ground-based conventional allometric approaches are often challenging to execute consistently across individuals and through time, increasing the difficulty of the required measurements and consequently the accuracy of the resulting products. To constrain the uncertainty associated with these campaigns, and to expand the extent of our measurement capability, we made repeat measurements of vegetation biomass in a semi-arid piñon-juniper woodland using structure-from-motion (SfM) techniques. We used high-spatial resolution overlapping aerial images and high-accuracy ground control points collected from both manned aircraft and multi-rotor UAS platforms, to generate digital surface model (DSM) for our experimental region. We extracted high-precision canopy volumes from the DSM and compared these to the vegetation allometric data, s to generate high precision canopy volume models. We used these models to predict the drivers of allometric equations for Pinus edulis and Juniperous monosperma (canopy height, diameter at breast height, and root collar diameter). Using this approach, we successfully accounted for the carbon stocks in standing live and standing dead vegetation across a 9 ha region, which contained 12.6 Mg / ha of standing dead biomass, with good agreement to our field plots. Here we present the initial results from an object oriented workflow which aims to automate the biomass estimation process of tree crown delineation and volume calculation, and partition

Regulation and acclimation of leaf gas exchange in a piñon-juniper woodland exposed to three different precipitation regimes.

Science.gov (United States)

Limousin, Jean-Marc; Bickford, Christopher P; Dickman, Lee T; Pangle, Robert E; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Osuna, Jessica L; Pockman, William T; McDowell, Nate G

2013-10-01

Leaf gas-exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas-exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon-juniper Pinus edulis-Juniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (-45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas-exchange rates under well-watered conditions, leaf-specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade-off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA. © 2013 John Wiley & Sons Ltd.

Vegetation Response to Western Juniper Slash Treatments

Science.gov (United States)

O'Connor, Casey; Miller, Rick; Bates, Jonathan D.

2013-09-01

The expansion of piñon-juniper woodlands the past 100 years in the western United States has resulted in large scale efforts to kill trees and recover sagebrush steppe rangelands. It is important to evaluate vegetation recovery following woodland control to develop best management practices. In this study, we compared two fuel reduction treatments and a cut-and-leave (CUT) treatment used to control western juniper ( Juniperus occidentalis spp. occidentalis Hook.) of the northwestern United States. Treatments were; CUT, cut-and-broadcast burn (BURN), and cut-pile-and-burn the pile (PILE). A randomized complete block design was used with five replicates of each treatment located in a curl leaf mahogany ( Cercocarpus ledifolius Nutt. ex Torr. & A. Gray)/mountain big sagebrush ( Artemisia tridentata Nutt. spp. vaseyana (Rydb.) Beetle)/Idaho fescue ( Festuca idahoensis Elmer) association. In 2010, 4 years after tree control the cover of perennial grasses (PG) [Sandberg's bluegrass ( Poa secunda J. Pres) and large bunchgrasses] were about 4 and 5 % less, respectively, in the BURN (7.1 ± 0.6 %) than the PILE (11.4 ± 2.3 %) and CUT (12.4 ± 1.7 %) treatments ( P < 0.0015). In 2010, cover of invasive cheatgrass ( Bromus tectorum L.) was greater in the BURN (6.3 ± 1.0 %) and was 50 and 100 % greater than PILE and CUT treatments, respectively. However, the increase in perennial bunchgrass density and cover, despite cheatgrass in the BURN treatment, mean it unlikely that cheatgrass will persist as a major understory component. In the CUT treatment mahogany cover increased 12.5 % and density increased in from 172 ± 25 to 404 ± 123 trees/ha. Burning, killed most or all of the adult mahogany, and mahogany recovery consisted of 100 and 67 % seedlings in the PILE and BURN treatments, respectively. After treatment, juniper presence from untreated small trees (<1 m tall; PILE and CUT treatments) and seedling emergence (all treatments) represented 25-33 % of pre-treatment tree

Western Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

Science.gov (United States)

The rapid expansion of western juniper into neighboring plant communities during the past 130 years has been linked to increased soil erosion; reduced forage production; altered wildlife habitat; changes in plant community composition, structure, and biodiversity. Impacts of post-settlement woodland...

Drought predisposes piñon-juniper woodlands to insect attacks and mortality.

Science.gov (United States)

Gaylord, Monica L; Kolb, Thomas E; Pockman, William T; Plaut, Jennifer A; Yepez, Enrico A; Macalady, Alison K; Pangle, Robert E; McDowell, Nate G

2013-04-01

To test the hypothesis that drought predisposes trees to insect attacks, we quantified the effects of water availability on insect attacks, tree resistance mechanisms, and mortality of mature piñon pine (Pinus edulis) and one-seed juniper (Juniperus monosperma) using an experimental drought study in New Mexico, USA. The study had four replicated treatments (40 × 40 m plot/replicate): removal of 45% of ambient annual precipitation (H2 O-); irrigation to produce 125% of ambient annual precipitation (H2 O+); a drought control (C) to quantify the impact of the drought infrastructure; and ambient precipitation (A). Piñon began dying 1 yr after drought initiation, with higher mortality in the H2 O- treatment relative to other treatments. Beetles (bark/twig) were present in 92% of dead trees. Resin duct density and area were more strongly affected by treatments and more strongly associated with piñon mortality than direct measurements of resin flow. For juniper, treatments had no effect on insect resistance or attacks, but needle browning was highest in the H2 O- treatment. Our results provide strong evidence that ≥ 1 yr of severe drought predisposes piñon to insect attacks and increases mortality, whereas 3 yr of the same drought causes partial canopy loss in juniper. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Ecohydrological Linkages, Multi-scale Processes, Temporal Variability, and Drivers of Change in a Degraded Pinyon-Juniper Watershed: Implications for Erosion Modeling

Science.gov (United States)

Allen, C. D.

2006-12-01

In 1993 long-term research began on the runoff and erosion dynamics of a pinyon-juniper woodland hillslope at Bandelier National Monument in northern New Mexico (USA). In the 1.09 ha Frijolito watershed, erosion has been continuously studied at 3 spatial scales: 1 square meter, about 1000 square meters, and the entire watershed. This site is currently representative of degraded woodlands of pinyon (Pinus edulis) and one-seed juniper (Juniperus monosperma) in this region, exhibiting marked connectivity of exposed bare soil interspaces between tree canopy patches and obvious geomorphic signs of accelerated soil erosion (e.g., pedestalling, actively expanding rill networks). Ecological and land use histories show that this site has undergone a number of dramatic ecohydrological shifts since ca. C.E. 1850, transitioning from: 1) open ponderosa pine (Pinus ponderosa) overstory with limited pinyon-juniper component and substantial herbaceous understory that supported surface fires and constrained soil erosion, to; 2) ponderosa pine with reduced herbaceous cover due to livestock grazing after ca.1870, resulting in collapse of the surface fire regime and increased establishment of young pinyon and juniper trees, to; 3) mortality of all of the ponderosa pine during the extreme drought of the 1950s, leaving eroding pinyon-juniper woodland, to; 4) mortality of all mature pinyon at or above sapling size during the 2002-2003 drought, with juniper now the only dominant woody species. Detailed measurements since 1993 document high rates of soil erosion (> 2.75 Mg/ha/year on average at the watershed scale) that are rapidly stripping the local soils. Long-term observations are needed to distinguish short-term variability from longer term trends, as measurements of runoff and erosion show extreme variability at multiple time scales since 1993. The multi-scale erosion data from the Frijolito watershed reveal little dropoff in erosion rate (g/meter-squared) between the one meter

Woodland recovery following drought-induced tree mortality across an environmental stress gradient.

Science.gov (United States)

Redmond, Miranda D; Cobb, Neil S; Clifford, Michael J; Barger, Nichole N

2015-10-01

Recent droughts and increasing temperatures have resulted in extensive tree mortality across the globe. Understanding the environmental controls on tree regeneration following these drought events will allow for better predictions of how these ecosystems may shift under a warmer, drier climate. Within the widely distributed piñon-juniper woodlands of the southwestern USA, a multiyear drought in 2002-2004 resulted in extensive adult piñon mortality and shifted adult woodland composition to a juniper-dominated, more savannah-type ecosystem. Here, we used pre- (1998-2001) and 10-year post- (2014) drought stand structure data of individually mapped trees at 42 sites to assess the effects of this drought on tree regeneration across a gradient of environmental stress. We found declines in piñon juvenile densities since the multiyear drought due to limited new recruitment and high (>50%) juvenile mortality. This is in contrast to juniper juvenile densities, which increased over this time period. Across the landscape, piñon recruitment was positively associated with live adult piñon densities and soil available water capacity, likely due to their respective effects on seed and water availability. Juvenile piñon survival was strongly facilitated by certain types of nurse trees and shrubs. These nurse plants also moderated the effects of environmental stress on piñon survival: Survival of interspace piñon juveniles was positively associated with soil available water capacity, whereas survival of nursed piñon juveniles was negatively associated with perennial grass cover. Thus, nurse plants had a greater facilitative effect on survival at sites with higher soil available water capacity and perennial grass cover. Notably, mean annual climatic water deficit and elevation were not associated with piñon recruitment or survival across the landscape. Our findings reveal a clear shift in successional trajectories toward a more juniper-dominated woodland and highlight the

Woody debris dynamics in Interior West forests and woodlands

Science.gov (United States)

John D. Shaw; James Long; Raffaella Marzano; Matteo Garbarino

2012-01-01

Managers are interested in the dynamics of down woody material because of its role as a fuel component, a feature of wildlife habitat, a carbon pool, and other characteristics. We analyzed nearly 9,000 plots from the Interior West, spanning the range from sparse juniper and mesquite woodland to dense spruce-fir forests, in order to characterize down woody material as...

Pinon and Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

Science.gov (United States)

Tausch, R.J.; Miller, R.F.; Roundy, B.A.; Chambers, J.C.

2009-01-01

Pinon-juniper woodlands are an important vegetation type in the Great Basin. Old-growth and open shrub savanna woodlands have been present over much of the last several hundred years. Strong evidence indicates these woodlands have experienced significant tree infilling and major expansion in their distribution since the late 1800s by encroaching into surrounding landscapes once dominated by shrubs and herbaceous vegetation. Both infilling and expansion affects soil resources, plant community structure and composition, water and nutrient cycles, forage production, wildlife habitat, biodiversity, and fire patterns across the landscape. Another impact is the shift from historic fire regimes to larger and more intense wildfires that are increasingly determining the future of this landscape. This publication helps biologists and land managers consider how to look at expansion of woodlands and determine what questions to ask to develop a management strategy, including prescribed fire or other practices.

Effects of a spring prescribed burn on the soil seed bank in sagebrush steppe exhibiting pinyon-juniper expansion

Science.gov (United States)

Elizabeth A. Allen; Jeanne C. Chambers; Robert S. Nowak

2008-01-01

Pinyon-juniper (Pinus monophylla-Juniperus osteosperma) woodlands are expanding into shrubsteppe ecosystems in western portions of the Great Basin. Often, highly competitive trees displace the understory, and prescribed fire is increasingly used as a restoration tool. To inform management decisions about post-fire recovery, we...

Pinon-juniper management research at Corona Range and Livestock Research Center in Central New Mexico

Science.gov (United States)

Andres Cibils; Mark Petersen; Shad Cox; Michael Rubio

2008-01-01

Description: New Mexico State University's Corona Range and Livestock Research Center (CRLRC) is located in a pinon-juniper (PJ)/grassland ecotone in the southern Basin and Range Province in south central New Mexico. A number of research projects conducted at this facility revolve around soil, plant, livestock, and wildlife responses to PJ woodland management. The...

Tree Mortality Decreases Water Availability and Ecosystem Resilience to Drought in Piñon-Juniper Woodlands in the Southwestern U.S.: Tree Mortality in Semiarid Biomes

Energy Technology Data Exchange (ETDEWEB)

Morillas, L. [Department of Biology, University of New Mexico, Albuquerque NM USA; Now at Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver British Columbia Canada; Pangle, R. E. [Department of Biology, University of New Mexico, Albuquerque NM USA; Maurer, G. E. [Department of Biology, University of New Mexico, Albuquerque NM USA; Now at Department of Environmental Science, Policy, and Management, University of California, Berkeley CA USA; Pockman, W. T. [Department of Biology, University of New Mexico, Albuquerque NM USA; McDowell, N. [Earth Systems Analysis and Modeling, Pacific Northwest National Laboratory, Richland WA USA; Huang, C. -W. [Department of Biology, University of New Mexico, Albuquerque NM USA; Krofcheck, D. J. [Department of Biology, University of New Mexico, Albuquerque NM USA; Fox, A. M. [School of Natural Resources and the Environment, University of Arizona, Tucson AZ USA; Sinsabaugh, R. L. [Department of Biology, University of New Mexico, Albuquerque NM USA; Rahn, T. A. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM USA; Litvak, M. E. [Department of Biology, University of New Mexico, Albuquerque NM USA

2017-12-01

Climate-driven tree mortality has increased globally in response to warmer temperature and more severe drought. To examine how tree mortality in semi-arid biomes impacts surface water balance, we experimentally manipulated a piñon-juniper (PJ) woodland by girdling all adult piñon trees in a 4 ha area, decreasing piñon basal area by ~65%. Over 3.5 years (2009-2013), we compared water flux measurements from this girdled site with those from a nearby intact PJ woodland. Before and after girdling, the ratio of evapotranspiration (ET) to incoming precipitation was similar between the two sites. Girdling altered the partitioning of ET such that the contribution of canopy transpiration to ET decreased 9-14% over the study period, relative to the intact control, while non-canopy ET increased. We attributed the elevated non-canopy ET in the girdled site each year to winter increases in sublimation, and summer increases in both soil evaporation and below-canopy transpiration. Although we expected that mortality of a canopy dominant would increase the availability of water and other resources to surviving vegetation, we observed a decrease in both soil volumetric water content and sap flow rates in the remaining trees at the girdled site, relative to the control. This post-girdling decrease in the performance of the remaining trees occurred during the severe 2011-2012 drought, suggesting that piñon mortality may trigger feedback mechanisms that leave PJ woodlands drier relative to undisturbed sites, and potentially more vulnerable to drought.

Variation in ant populations with elevation, tree cover, and fire in a pinyon-juniper-dominated watershed

Science.gov (United States)

Eugenie M. MontBlanc; Jeanne C. Chambers; Peter E. Brussard

2007-01-01

Climate change and fire suppression have facilitated expansion of pinyon-juniper woodlands into sagebrush- steppe ecosystems of the Great Basin, USA, resulting in a loss of biological diversity. To assess the effects of using prescribed fire in restoration efforts, ant abundance, species richness, and composition were examined pre- and post-burn along the elevation and...

Decreased carbon limitation of litter respiration in a mortality-affected pinon-juniper woodland

Science.gov (United States)

Erin Berryman; John D. Marshall; Thom Rahn; Marcie Litvak; John Butnor

2013-01-01

Microbial respiration depends on microclimatic variables and carbon (C) substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting pinon-juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of...

Reduced transpiration response to precipitation pulses precedes mortality in a piñon-juniper woodland subject to prolonged drought.

Science.gov (United States)

Plaut, Jennifer A; Wadsworth, W Duncan; Pangle, Robert; Yepez, Enrico A; McDowell, Nate G; Pockman, William T

2013-10-01

Global climate change is predicted to alter the intensity and duration of droughts, but the effects of changing precipitation patterns on vegetation mortality are difficult to predict. Our objective was to determine whether prolonged drought or above-average precipitation altered the capacity to respond to the individual precipitation pulses that drive productivity and survival. We analyzed 5 yr of data from a rainfall manipulation experiment in piñon-juniper (Pinus edulis-Juniperus monosperma) woodland using mixed effects models of transpiration response to event size, antecedent soil moisture, and post-event vapor pressure deficit. Replicated treatments included irrigation, drought, ambient control and infrastructure control. Mortality was highest under drought, and the reduced post-pulse transpiration in the droughted trees that died was attributable to treatment effects beyond drier antecedent conditions and reduced event size. In particular, trees that died were nearly unresponsive to antecedent shallow soil moisture, suggesting reduced shallow absorbing root area. Irrigated trees showed an enhanced response to precipitation pulses. Prolonged drought initiates a downward spiral whereby trees are increasingly unable to utilize pulsed soil moisture. Thus, the additive effects of future, more frequent droughts may increase drought-related mortality. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Use of Direct and Indirect Estimates of Crown Dimensions to Predict One Seed Juniper Woody Biomass Yield for Alternative Energy Uses

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Throughout the western United States there is increased interest in utilizing woodland biomass as an alternative energy source. We conducted a pilot study to predict one seed juniper (Juniperus monosperma) chip yield from tree-crown dimensions measured on the ground or derived from Very Large Scale ...

Growth and yield of southwest pinyon-juniper woodlands: Modeling growth and drought effects

Science.gov (United States)

John D. Shaw

2008-01-01

A complex of drought, insects, and disease caused widespread mortality in the pinyon-juniper forest types of the American Southwest in recent years. Most public and scientific attention has been given to the extent of drought-related mortality and causal factors. At the same time, there has been relatively little attention given to non-lethal drought effects. As part...

First year soil and runoff response to compaction after mechanical mastication of juniper woodland

Science.gov (United States)

Utah juniper (Juniperus osteosperma) expansion in the west has resulted in increased wildfires and has led land managers to search for effective fuel control methods. Mechanical mastication using a large, rotating drum with carbide teeth mounted on a tractor allows managers to selectively control tr...

Defining modeling parameters for juniper trees assuming pleistocene-like conditions at the NTS

International Nuclear Information System (INIS)

Tarbox, S.R.; Cochran, J.R.

1994-01-01

This paper addresses part of Sandia National Laboratories' (SNL) efforts to assess the long-term performance of the Greater Confinement Disposal (GCD) facility located on the Nevada Test Site (NTS). Of issue is whether the GCD site complies with 40 CFR 191 standards set for transuranic (TRU) waste burial. SNL has developed a radionuclide transport model which can be used to assess TRU radionuclide movement away from the GCD facility. An earlier iteration of the model found that radionuclide uptake and release by plants is an important aspect of the system to consider. Currently, the shallow-rooted plants at the NTS do not pose a threat to the integrity of the GCD facility. However, the threat increases substantially it deeper-rooted woodland species migrate to the GCD facility, given a shift to a wetter climate. The model parameters discussed here will be included in the next model iteration which assumes a climate shift will provide for the growth of juniper trees at the GCD facility. Model parameters were developed using published data and wherever possible, data were taken from juniper and pinon-juniper studies that mirrored as many aspects of the GCD facility as possible

Decreased carbon limitation of litter respiration in a mortality-affected piñon–juniper woodland

Directory of Open Access Journals (Sweden)

E. Berryman

2013-03-01

Full Text Available Microbial respiration depends on microclimatic variables and carbon (C substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting piñon–juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of root exudation. To determine piñon mortality effects on C and water limitation of microbial respiration, we applied field amendments (sucrose and water to two piñon–juniper sites in central New Mexico, USA: one with a recent (2 flux on the girdled site and a non-significant increase on the control. We speculate that the reduction may have been driven by water-induced carbonate dissolution, which serves as a sink for CO2 and would reduce the net flux. Widespread piñon mortality may decrease labile C limitation of litter respiration, at least during the first growing season following mortality.

Determining the Impact of Forest Mortality in Semi-Arid Woodlands on Local and Regional Carbon Dynamics

Energy Technology Data Exchange (ETDEWEB)

Litvak, Marcy [University of New Mexico

2018-04-09

We received funds in July 2012, and with supplemental funds, this funding ended in July 2017. Our overall project goals were to quantify the consequences of pinon mortality for carbon, water and energy exchange in pinon-juniper woodlands. To do this, we have been continuously measuring carbon, water and energy exchange using eddy covariance, over two pinon-juniper woodlands in central New Mexico. In one site, we girdled 1632 trees in the 4 ha surrounding the tower in Sept 2009. The other site, only 5 km away on the same plateau, was left intact, to serve as a control. We used this paired tower approach so we could directly evaluate the differences between how fluxes from disturbed and intact woodlands respond to the exact same climate conditions. In addition to eddy covariance measured fluxes from the two woodlands, we also made sap flux measurements, biomass, gas exchange, and soil respiration fluxes simultaneously in the two sites. The overall objective of this proposal is to measure the carbon and climate forcing consequences of widespread coniferous mortality events in the Southwestern US. We will incorporate these findings into a land surface model to understand the long term carbon dynamics of these mortality events and use remote sensing maps of mortality in PJ woodlands in NM to scale the implications of these events to regional carbon dynamics and atmospheric CO2. In 2013, our control PJ woodland experienced a natural pinon mortality event as bark beetles invaded the area. We received supplemental funds to quantify the extent of the mortality and how it progresses, and to add remotely sensed imagery to aid in this and estimate the loss of biomass at the site due to mortality. Finally, we have been exploring the use of both CLM and SIPNET to analyze how well these models to in representing how these woodlands change following pinon mortality. Here, I present the results of what we have learned in these areas: 1) how carbon, water and energy fluxes, have

Drought-Related Mortality in Pinyon-Juniper Woodlands: A Test Case for the FIA Annual Inventory System

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John D. Shaw

2006-01-01

Several years of drought in the Southwest United States are associated with widespread mortality in the pinyon-juniper forest type. A complex of drought, insects, and disease is responsible for pinyon mortality rates approaching 100 percent in some areas, while other areas have experienced little or no mortality. Implementation of the Forest Inventory and Analysis...

Soils mediate the impact of fine woody debris on invasive and native grasses as whole trees are mechanically shredded into firebreaks in piñon-juniper woodlands

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Aanderud, Zachary T.; Schoolmaster, Donald R.; Rigby, Deborah; Bybee, Jordon; Campbell, Tayte; Roundy, Bruce A.

2017-01-01

To stem wildfires, trees are being mechanically shredded into firebreaks with the resulting fine woody debris (FWD) potentially exerting immense control over soil and plants. We linked FWD-induced changes in microbial activity and nutrient availability to the frequency of Bromus tectorum and three native, perennial grasses across 31 piñon-juniper woodlands, UT, USA. Using a series of mixed models, we found that FWD increased the frequency of three of the four grasses by at least 12%. Deep, as opposed to shallow, soils mediated frequencies following FWD additions but only partially explained the variation in Bromus and Pseudoroegneria spicata. Although fertile areas associated with tree-islands elicited no response, FWD-induced increases in nitrogen mineralization in deep soils (15–17 cm) caused the frequency of the exotic and Pseudoroegneria to rise. Higher phosphorus availability in FWD-covered surface soils (0–2 cm) had no impact on grasses. FWD altered deep soil respiration, and deep and shallow microbial biomass structuring Pseudoroegneria frequencies, suggesting that microorganism themselves regulated Pseudoroegneria. The positive effects of FWD on grass frequencies intensified over time for natives but diminished for Bromus. Our results demonstrate that microorganisms in deeper soils helped mediate species-specific responses to disturbance both facilitating exotic invasion and promoting native establishment.

Both gas chromatography and an electronic nose reflect chemical polymorphism of juniper shrubs browsed or avoided by sheep.

Science.gov (United States)

Markó, Gábor; Novák, Ildikó; Bernáth, Jeno; Altbäcker, Vilmos

2011-07-01

Chemical polymorphism may contribute to variation in browsing damage by mammalian herbivores. Earlier, we demonstrated that essential oil concentration in juniper, Juniperus communis, was negatively associated with herbivore browsing. The aim of the present study was to characterize the volatile chemical composition of browsed and non-browsed J. communis. By using either gas chromatography with flame ionization detection (GC-FID) or an electronic nose device, we could separate sheep-browsed or non-browsed juniper shrubs by their essential oil pattern and complex odor matrix. The main components of the essential oil from J. communis were monoterpenes. We distinguished three chemotypes, dominated either by α-pinene, sabinene, or δ-3-carene. Shrubs belonging to the α-pinene- or sabinene-dominated groups were browsed, whereas all individuals with the δ-3-carene chemotype were unused by the local herbivores. The electronic nose also separated the browsed and non-browsed shrubs indicating that their odor matrix could guide sheep browsing. Responses of sheep could integrate the post-ingestive effects of plant secondary metabolites with sensory experience that stems from odor-phytotoxin interactions. Chemotype diversity could increase the survival rate in the present population of J. communis as certain shrubs could benefit from relatively better chemical protection against the herbivores.

Commercialization analysis for fuels from Pinyon-Juniper biomass

International Nuclear Information System (INIS)

Morris, G.P.

1993-01-01

Pinyon-Juniper (P-J) is a predominant forest type in the Southwestern US, and in many areas it is considered a hinderance to optimal land use management. There is only limited commercial demand for the traditional products that are produced from PJ biomass, like Christmas trees, fence poles, and firewood, and their production does not always promote overall land-management goals. This research effort, which is supported by the DOE through the Western Regional Biomass Energy Program, identifies commercially feasible energy markets to promote sustainable land clearing operations for alternative land uses of P-J woodlands in Eastern Nevada. All of the woodlands under consideration are federal lands managed by the U.S. Bureau of Land Management, which is supportive of our concept. Three possible markets are available or could reasonably be developed to use fuels derived from PJ biomass in Nevada: (1) The existing market for biomass power-plant fuels in California. (2) The emerging market for fuels for residential pellet-burning stoves. (3) The development of a biomass-fired power plant in the Eastern Nevada Area. The study analyzes the cost of harvesting, processing, transporting, and delivering fuels derived from P-J biomass, and identifies commercialization strategies for bringing these fuels to market. The best opportunity for near term commercial conversion of P-J biomass to fuel lies in the area of entering the pellet-stove fuel market, establishing a 10,000 ton per year pelletizing facility in Lincoln County. Such a facility would have excellent access to markets in Las Vegas, Phoenix, Denver, and Salt Lake City

Evaluation of the seasonal and annual abortifacient risk of western juniper trees on Oregon rangelands: Abortion risk of western juniper trees

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Western juniper trees can cause late term abortions in cattle, similar to ponderosa pine trees. Analyses of western juniper trees from 35 locations across the state of Oregon suggest that western juniper trees in all areas present an abortion risk in pregnant cattle. Results from this study demonstr...

Spanish juniper gain expansion opportunities by counting on a functionally diverse dispersal assemblage community.

Science.gov (United States)

Escribano-Ávila, Gema; Pías, Beatriz; Sanz-Pérez, Virginia; Virgós, Emilio; Escudero, Adrián; Valladares, Fernando

2013-10-01

Seed dispersal is typically performed by a diverse array of species assemblages with different behavioral and morphological traits which determine dispersal quality (DQ, defined as the probability of recruitment of a dispersed seed). Fate of ecosystems to ongoing environmental changes is critically dependent on dispersal and mainly on DQ in novel scenarios. We assess here the DQ, thus the multiplicative effect of germination and survival probability to the first 3 years of life, for seeds dispersed by several bird species (Turdus spp.) and carnivores (Vulpes vulpes, Martes foina) in mature woodland remnants of Spanish juniper (Juniperus thurifera) and old fields which are being colonized by this species. Results showed that DQ was similar in mature woodlands and old fields. Germination rate for seeds dispersed by carnivores (11.5%) and thrushes (9.12%) was similar, however, interacted with microhabitat suitability. Seeds dispersed by carnivores reach the maximum germination rate on shrubs (16%), whereas seeds dispersed by thrushes did on female juniper canopies (15.5) indicating that each group of dispersers performed a directed dispersal. This directional effect was diluted when survival probability was considered: thrushes selected smaller seeds which had higher mortality in the seedling stage (70%) in relation to seedlings dispersed by carnivores (40%). Overall, thrushes resulted low-quality dispersers which provided a probability or recruitment of 2.5%, while a seed dispersed by carnivores had a probability of recruitment of 6.5%. Our findings show that generalist dispersers (i.e., carnivores) can provide a higher probability of recruitment than specialized dispersers (i.e., Turdus spp.). However, generalist species are usually opportunistic dispersers as their role as seed dispersers is dependent on the availability of trophic resources and species feeding preferences. As a result, J. thurifera dispersal community is composed by two functional groups of

Modeling dynamics of western juniper under climate change in a semiarid ecosystem

Science.gov (United States)

Shrestha, R.; Glenn, N. F.; Flores, A. N.

2013-12-01

Modeling future vegetation dynamics in response to climate change and disturbances such as fire relies heavily on model parameterization. Fine-scale field-based measurements can provide the necessary parameters for constraining models at a larger scale. But the time- and labor-intensive nature of field-based data collection leads to sparse sampling and significant spatial uncertainties in retrieved parameters. In this study we quantify the fine-scale carbon dynamics and uncertainty of juniper woodland in the Reynolds Creek Experimental Watershed (RCEW) in southern Idaho, which is a proposed critical zone observatory (CZO) site for soil carbon processes. We leverage field-measured vegetation data along with airborne lidar and timeseries Landsat imagery to initialize a state-and-transition model (VDDT) and a process-based fire-model (FlamMap) to examine the vegetation dynamics in response to stochastic fire events and climate change. We utilize recently developed and novel techniques to measure biomass and canopy characteristics of western juniper at the individual tree scale using terrestrial and airborne laser scanning techniques in RCEW. These fine-scale data are upscaled across the watershed for the VDDT and FlamMap models. The results will immediately improve our understanding of fine-scale dynamics and carbon stocks and fluxes of woody vegetation in a semi-arid ecosystem. Moreover, quantification of uncertainty will also provide a basis for generating ensembles of spatially-explicit alternative scenarios to guide future land management decisions in the region.

SELECTING ANGORA GOATS TO CONSUME MORE JUNIPER

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Christopher John Lupton

2009-02-01

Full Text Available This research project was initiated in 2003 to develop a more effective tool for biological management of invading juniper species on rangelands through herbivory by Angora goats.  After we had established that juniper consumption in free-ranging goats has a genetic component (heritability = 13%, male and female goats were bred selectively for above- (high and below-average (low juniper consumption that was estimated by fecal near-infrared reflectance spectroscopy. Divergent lines are being produced to facilitate the identification of physiological mechanisms that permit some goats to consume considerably more juniper than others as a regular component of their diet.  Because diet is known to affect growth and fiber production, another objective of the project is to establish the effects of the selection protocol on body weights, fleece weights, and fiber characteristics.  Mature females (age > 1.5 yr and kids were maintained on rangeland and shorn twice a year.  Extreme high- and low-consuming yearling males (10 of each per year were evaluated annually in a central performance test.  The selection protocol resulted in average EBV for percentage juniper consumption of 3.9 and -0.4 (P 0.1 in body weight, mohair production and properties between high and low consumers.  However, the adult data for the extreme males indicated that high consuming males have lower body weights than low consumers (53.8 vs. 57.9 kg, P = 0.01. Differences in body weight and several mohair production and quality traits have also been detected in the mature females but at this early stage of the selection program, no substantial differences have been observed and certainly none that would have an economic impact for producers.  Ultimately, we expect to demonstrate that the high-consuming line controls juniper more effectively than either the low-consuming line or unselected Angora goats.  Subsequently, we plan to release high juniper

Root-associated fungal community response to drought-associated changes in vegetation community.

Science.gov (United States)

Dean, Sarah L; Warnock, Daniel D; Litvak, Marcy E; Porras-Alfaro, Andrea; Sinsabaugh, Robert

2015-01-01

Recent droughts in southwestern USA have led to large-scale mortality of piñon (Pinus edulis) in piñon-juniper woodlands. Piñon mortality alters soil moisture, nutrient and carbon availability, which could affect the root-associated fungal (RAF) communities and therefore the fitness of the remaining plants. We collected fine root samples at a piñon-juniper woodland and a juniper savannah site in central New Mexico. Roots were collected from piñon and juniper (Juniperus monosperma) trees whose nearest neighbors were live piñon, live juniper or dead piñon. RAF communities were analyzed by 454 pyrosequencing of the universal fungal ITS region. The most common taxa were Hypocreales and Chaetothyriales. More than 10% of ITS sequences could not be assigned taxonomy at the phylum level. Two of the unclassified OTUs significantly differed between savanna and woodland, had few like sequences in GenBank and formed new fungal clades with other unclassified RAF from arid plants, highlighting how little study has been done on the RAF of arid ecosystems. Plant host or neighbor did not affect RAF community composition. However, there was a significant difference between RAF communities from woodland vs. savanna, indicating that abiotic factors such as temperature and aridity might be more important in structuring these RAF communities than biotic factors such as plant host or neighbor identity. Ectomycorrhizal fungi (EM) were present in juniper as well as piñon in the woodland site, in contrast with previous research, but did not occur in juniper savanna, suggesting a potential shared EM network with juniper. RAF richness was lower in hosts that were neighbors of the opposite host. This may indicate competitive exclusion between fungi from different hosts. Characterizing these communities and their responses to environment and plant neighborhood is a step toward understanding the effects of drought on a biome that spans 19,000,000 ha of southwestern USA. © 2015 by The

Off-road transport of pinyon/juniper

Science.gov (United States)

J. Klepac; B. Rummer

2012-01-01

A 8-wheel forwarder was observed while transporting pinyon pine (P. edulis) and Utah juniper (J. osteosperma) from woods to landing in southern Utah. The forwarder was part of a 2-machine system used to treat pinyon-juniper stands. Trees were felled using a rubber tracked skid steer with a shear head, then transported to a collection point with a Ponsse Buffalo King 20...

Mechanism of cadmium ion removal by base treated juniper fiber

Science.gov (United States)

Soo-Hong Min; J.K. Park; James S. Han; Eun Woo Shin

2003-01-01

Pinyon juniper, Juniperus Monosperma, is a small-diameter and underutilized (SDU) lignocellulosic material. Evaluated were efficacy of base-treated juniper fiber (BTJF) sample for cadmium (Cd 2+ ) sorption and the viability of juniper fiber as a sorbent for the removal of Cd 2+ from water. Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated that...

Commercialization of fuels from Pinyon-Juniper biomass in Nevada

International Nuclear Information System (INIS)

Morris, G.P.

1994-01-01

This study analyzes and defines energy applications and markets that could stimulate the commercial use of Eastern Nevada's Pinyon-Juniper resources. The commercialization potential for producing energy from Pinyon-Juniper biomass is analyzed by examining the resource base and resource availability for a commercial harvesting and processing operation. The study considered the spectrum of available equipment and technology for carrying out harvesting and processing operations, investigated the markets that might be able to use energy products derived from Pinyon-Juniper biomass, analyzed the costs of harvesting, processing, and transporting Pinyon-Juniper fuels, and set forth a plan for developing the commercial potential of these resources. The emerging residential pellet-fuels market is a promising entry market for the commercialization of an energy from Pinyon-Juniper biomass industry in Eastern Nevada, although there are serious technical issues that may render Pinyon-Juniper biomass an unsuitable feedstock for the manufacture of pellet fuels. These issues could be investigated at a moderate cost in order to determine whether to proceed with development efforts in this direction. In the longer term, one or two biomass-fired power plants in the size range of 5-10 MW could provide a stable and predictable market for the production and utilization of fuels derived from local Pinyon-Juniper biomass resources, and would provide valuable economic and environmental benefits to the region. Municipal utility ownership of such facilities could help to enhance the economic benefits of the investments by qualifying them for federal energy credits and tax-free financing

Study of the thermohygrometric conditions of Juniperus turbinata habitat in the island of El Hierro (Canary Islands)

Science.gov (United States)

Salva-Catarineu, Montserrat; Salvador-Franch, Ferran; López-Bustins, Joan Albert; Padrón-Padrón, Perdro A.; Cortés-Lucas, Amparo

2015-04-01

The biggest population of Juniperus turbinata throughout the Canary Islands is located in the island of El Hierro. The current extent of juniper woodlands is very small compared with the potential distribution due to heavy exploitation for centuries. Nowadays, the recovery of its natural habitat has such a high environmental and scenic interest since this is a protected species in Europe; however, an improved understanding of the environmental factors that help or limit its recovery is indispensable. Under the JUNITUR project the populations of juniper woodlands in El Hierro are being studied, which are subjected to highly different environments. These environments are mainly determined by their altitude and exposure to NE trade winds. The main objective of this study is to compare the thermohygrometric conditions of three juniper woodlands, located at different altitude and orientation in El Hierro, which present different recovery rates. We are currently using air sensor data loggers fixed to tree branches for recording hourly temperature and humidity data in the three study areas. For this preliminary approach, we analyse daily data of two annual cycles (from September 2012 to August 2014). Our first results show similar thermohygrometric annual cycles among the three study areas. The largest differences are detected in winter temperature and summer humidity between the north (to windward) and south (to leeward) faces of the island. The juniper woodland with a highest recovery rate shows the most extreme temperature conditions in both winter and summer seasons. This last juniper woodland is located leeward to trade winds at 996 m a.s.l. In general terms, the results of this research project might contribute to the knowledge of the juniper bioclimatology in the westernmost of the Canary Islands. Key words: bioclimatology, El Hierro, habitat, Juniperus turbinata, protected species

Physico-mechanical properties of Spanish juniper wood considering the effect of heartwood formation and the presence of defects and imperfections

Directory of Open Access Journals (Sweden)

Javier de la Fuente-Leon

2014-04-01

Full Text Available Aim of study: Determining the main physical and mechanical properties of Spanish juniper wood from Soria (Spain considering the effects of heartwood formation and the presence of defects and imperfections; and comparing the resulting characteristics with similar existing data for other regional softwood species of commercial interest. Area of study: Berlanga de Duero (Soria, Castilla y León, Spain.Material and Methods: Wood physico-mechanical performance was determined by Spanish UNE standards in order to provide proper comparisons to other regional softwood species. An individual tree representing average plot characteristics was selected in all eight 10 m radius circular plots that were established well-representing the heterogeneity of this woodland. The age of every tree was determined reading the number of growth rings at the base of each sampled tree. Every physico-mechanical property was assessed at least 4 times for every wood sample type (sapwood and heartwood, whether clear or with the presence of defects of each tree. Two-way ANOVA was run to assess significant differences in the results. Post hoc all pairwise comparisons were performed using Tukey's test (p < 0.05.Research highlights: Spanish juniper wood resulted harder than other regional commercial conifers, and showed semi-heavyweight heartwood and lightweight sapwood; whereas shrinkage figures remarked its great dimensional stability. The high presence of knots within heartwood made it even heavier, harder, and more resistant to compression parallel to grain. A commercial use of this rare precious wood may contribute to juniper forests preservation in the frame of forest sustainable management plans. Key words: heartwood effect; Juniperus thurifera L.; physico-mechanical wood properties; wood classification; wood defects.

Mechanical mastication of Utah juniper encroaching sagebrush steppe increases inorganic soil N

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Juniper (Juniperus spp.) has encroached millions of hectares of sagebrush (Artemisia spp.) steppe. Juniper mechanical mastication increases cover of understory species, but could increase resource availability and subsequently invasive plant species. We quantified the effects of juniper mastication ...

The western juniper resource of eastern Oregon, 1999.

Science.gov (United States)

David L. Azuma; Bruce A. Hiserote; Paul A. Dunham

2005-01-01

This report summarizes resource statistics for eastern Oregon's juniper forests, which are in Baker, Crook, Deschutes, Gilliam, Grant, Harney, Jefferson, Klamath, Lake, Malheur, Morrow, Sherman, Umatilla, Union, Wallowa, Wasco, and Wheeler Counties. We sampled all ownerships outside of the National Forest System; we report the statistics on juniper forest on...

Response of Spectral Reflectances and Vegetation Indices on Varying Juniper Cone Densities

Directory of Open Access Journals (Sweden)

Guillermo E. Ponce-Campos

2013-10-01

Full Text Available Juniper trees are widely distributed throughout the world and are common sources of allergies when microscopic pollen grains are transported by wind and inhaled. In this study, we investigated the spectral influences of pollen-discharging male juniper cones within a juniper canopy. This was done through a controlled outdoor experiment involving ASD FieldSpec Pro Spectroradiometer measurements over juniper canopies of varying cone densities. Broadband and narrowband spectral reflectance and vegetation index (VI patterns were evaluated as to their sensitivity and their ability to discriminate the presence of cones. The overall aim of this research was to assess remotely sensed phenological capabilities to detect pollen-bearing juniper trees for public health applications. A general decrease in reflectance values with increasing juniper cone density was found, particularly in the Green (545–565 nm and NIR (750–1,350 nm regions. In contrast, reflectances in the shortwave-infrared (SWIR, 2,000 nm to 2,350 nm region decreased from no cone presence to intermediate amounts (90 g/m2 and then increased from intermediate levels to the highest cone densities (200 g/m2. Reflectance patterns in the Red (620–700 nm were more complex due to shifting contrast patterns in absorptance between cones and juniper foliage, where juniper foliage is more absorbing than cones only within the intense narrowband region of maximum chlorophyll absorption near 680 nm. Overall, narrowband reflectances were more sensitive to cone density changes than the equivalent MODIS broadbands. In all VIs analyzed, there were significant relationships with cone density levels, particularly with the narrowband versions and the two-band vegetation index (TBVI based on Green and Red bands, a promising outcome for the use of phenocams in juniper phenology trait studies. These results indicate that spectral indices are sensitive to certain juniper phenologic traits that can potentially be

Dendrochronology of Utah Juniper (Juniperus osteosperma (Torr.) Little)

Science.gov (United States)

R. Justin Derose; Matthew F. Bekker; Roger Kjelgren; Brendan M. Buckley; James H. Speer; Eric B. Allen

2016-01-01

Utah juniper was a foundational species for the discipline of dendrochronology, having been used in the early 20th Century investigations of Mesa Verde, but has been largely ignored by dendrochronologists since. Here we present dendrochronological investigations of Utah juniper core and cross-sectional samples from four sites in northern Utah. We demonstrate that,...

Soil Seed Bank Responses to Postfire Herbicide and Native Seeding Treatments Designed to Control Bromus tectorum in a Pinyon–Juniper Woodland at Zion National Park, USA

Science.gov (United States)

Brooks, Matthew L.; Hondo Brisbin, graduate student; Andrea Thode, Associate Professor; Karen Weber, graduate student

2013-01-01

The continued threat of an invasive, annual brome (Bromus) species in the western United States has created the need for integrated approaches to postfire restoration. Additionally, the high germination rate, high seed production, and seed bank carryover of annual bromes points to the need to assay soil seed banks as part of monitoring programs. We sampled the soil seed bank to help assess the effectiveness of treatments utilizing the herbicide Plateau® (imazapic) and a perennial native seed mix to control annual Bromus species and enhance perennial native plant establishment following a wildfire in Zion National Park, Utah. This study is one of few that have monitored the effects of imazapic and native seeding on a soil seed bank community and the only one that we know of that has done so in a pinyon–juniper woodland. The study made use of untreated, replicated controls, which is not common for seed bank studies. One year posttreatment, Bromus was significantly reduced in plots sprayed with herbicide. By the second year posttreatment, the effects of imazapic were less evident and convergence with the controls was evident. Emergence of seeded species was low for the duration of the study. Dry conditions and possible interactions with imazapic probably contributed to the lack of emergence of seeded native species. The perennial grass sand dropseed outperformed the other species included in the seed mix. We also examined how the treatments affected the soil seed bank community as a whole. We found evidence that the herbicide was reducing several native annual forbs and one nonnative annual forb. However, overall effects on the community were not significant. The results of our study were similar to what others have found in that imazapic is effective in providing a short-term reduction in Bromus density, although it can impact emergence of nontarget species.

Cascading ecohydrological transitions: Multiple changes in vegetation and hydrology over the past 500 years for a semiarid forest/woodland boundary zone in New Mexico, USA

Science.gov (United States)

Allen, Craig D.

2010-05-01

On decadal and centennial time scales, multiple drivers can cause substantial changes in vegetation cover, which can trigger associated changes in runoff and erosion patterns and processes, with consequent feedbacks to the vegetation - cumulatively this can lead to a cascading series of non-equilibrial ecosystem changes through time. The work reported here provides a relatively detailed 500-year perspective of such changes on the mesas the eastern Jemez Mountains in northern New Mexico (USA), which today exhibit vegetation transitions along an elevational gradient between semiarid ponderosa pine (Pinus ponderosa) forests, mixed woodlands dominated by piñon (Pinus edulis) and one-seed juniper (Juniperus monosperma), and juniper savannas. Using multiple lines of evidence, a history of major ecosystem changes since ca. 1500 A.D. is reconstructed for a dynamic transition zone on one such mesa (Frijolito Mesa). Evidence includes intensive archaeological surveys, dendrochronological reconstructions of the demographic and spatial patterns of establishment and mortality for these three main tree species, dendrochronological reconstructions of fire regimes and climate patterns, broad-scale mapping of vegetation changes from historic aerial photographs since 1935, monitoring of vegetation from permanent transects since 1991, detailed soil maps and interpretations, intensive ecohydrological studies since 1993 on portions of this mesa, and research on the ecosystem effects of an experimental tree-thinning experiment conducted in 1997. Frijolito Mesa was fully occupied by large numbers of Native American farmers from the A.D. 1200's until the late 1500's, when they left these mesas for settlements in the adjoining Rio Grande Valley. Archaeological evidence and tree ages indicate that the mesa was likely quite deforested when abandoned, followed by episodic tree establishment dominated by ponderosa pine during the Little Ice Age. By the late 1700's Frijolito Mesa included

Do bark beetle sprays prevent Phloeosinus species from attacking cypress and juniper?

Science.gov (United States)

Chris Hayes; Tom DeGomez; Karen Clancy; Joel McMillin; John Anhold

2008-01-01

(Please note, this is an abstract only) Phloeosinus-caused mortality of Arizona cypress, (Cupressus arizonica), oneseed juniper, (Juniperus monosperma) and alligator juniper, (J. deppeana) has been observed at high levels in Arizona during the past 3 years. Currently, there are limited preventative measures to protect high-value cypress and juniper trees against...

Neighboring trees affect ectomycorrhizal fungal community composition in a woodland-forest ecotone.

Science.gov (United States)

Hubert, Nathaniel A; Gehring, Catherine A

2008-09-01

Ectomycorrhizal fungi (EMF) are frequently species rich and functionally diverse; yet, our knowledge of the environmental factors that influence local EMF diversity and species composition remains poor. In particular, little is known about the influence of neighboring plants on EMF community structure. We tested the hypothesis that the EMF of plants with heterospecific neighbors would differ in species richness and community composition from the EMF of plants with conspecific neighbors. We conducted our study at the ecotone between pinyon (Pinus edulis)-juniper (Juniperus monosperma) woodland and ponderosa pine (Pinus ponderosa) forest in northern Arizona, USA where the dominant trees formed associations with either EMF (P. edulis and P. ponderosa) or arbuscular mycorrhizal fungi (AMF; J. monosperma). We also compared the EMF communities of pinyon and ponderosa pines where their rhizospheres overlapped. The EMF community composition, but not species richness of pinyon pines was significantly influenced by neighboring AM juniper, but not by neighboring EM ponderosa pine. Ponderosa pine EMF communities were different in species composition when growing in association with pinyon pine than when growing in association with a conspecific. The EMF communities of pinyon and ponderosa pines were similar where their rhizospheres overlapped consisting of primarily the same species in similar relative abundance. Our findings suggest that neighboring tree species identity shaped EMF community structure, but that these effects were specific to host-neighbor combinations. The overlap in community composition between pinyon pine and ponderosa pine suggests that these tree species may serve as reservoirs of EMF inoculum for one another.

Antimycobacterial potential of the juniper berry essential oil in tap water.

Science.gov (United States)

Peruč, Dolores; Gobin, Ivana; Abram, Maja; Broznić, Dalibor; Svalina, Tomislav; Štifter, Sanja; Staver, Mladenka Malenica; Tićac, Brigita

2018-03-01

Mycobacterium avium complex-related diseases are often associated with poorly maintained hot water systems. This calls for the development of new control strategies. The aim of this study was to investigate the activity of essential oils (EOs) from the Mediterranean plants, common juniper, immortelle, sage, lavandin, laurel, and white cedar against Mycobacterium avium ssp. avium, Mycobacterium intracellulare, and Mycobacterium gordonae in culturing broth and freshwater as their most common habitat. To do that, we developed a new method of water microdilution to determine their minimal effective concentrations (MEC). The most active EO was the one from the common juniper with the MEC of 1.6 mg mL-1. Gas chromatography / mass spectrometry the juniper EO identified monoterpenes (70.54 %) and sesquiterpenes (25.9 %) as dominant component groups. The main monoterpene hydrocarbons were α-pinene, sabinene, and β-pinene. The juniper EO significantly reduced the cell viability of M. intracellulare and M. gordonae at MEC, and of M. avium at 2xMEC. Microscopic analysis confirmed its inhibitory effect by revealing significant morphological changes in the cell membrane and cytoplasm of all three bacteria. The mode of action of the juniper EO on the cell membrane was confirmed by a marked leakage of intracellular material. Juniper EO has a great practical potential as a complementary or alternative water disinfectant in hot water systems such as baths, swimming pools, spa pools, hot tubs, or even foot baths/whirlpools.

Cork oak woodlands patchiness

DEFF Research Database (Denmark)

Costa, Augusta; Madeira, Manuel; Plieninger, Tobias

2014-01-01

The cork oak (Quercus suber L.) woodlands of the agroforestry landscapes of Southwestern Iberia are undergoing drastic change due to severe natural and anthropogenic disturbances. These may eventually result in woodland loss or deforestation, the final step of an ongoing process of woodland degra...

Energy from the woodlands

Science.gov (United States)

Jerry Payne

2008-01-01

(Please note, this is an abstract only) The woodlands offer a significant opportunity for conversion of biomass to energy projects. With the vast acreage in the Southwest in the woodland type, and with the significant soil loss problems prevalent in this area, there is a dire need to treat the woodlands. Since there are limited opportunities for marketable products,...

75 FR 27550 - Electrical Interconnection of the Juniper Canyon I Wind Project

Science.gov (United States)

2010-05-17

... DEPARTMENT OF ENERGY Bonneville Power Administration Electrical Interconnection of the Juniper Canyon I Wind Project AGENCY: Bonneville Power Administration (BPA), Department of Energy (DOE). ACTION... would be generated from their proposed Juniper Canyon I Wind Energy Project (Wind Project) in Klickitat...

The roles of precipitation regimes on juniper forest encroachment on grasslands in Oklahoma

Science.gov (United States)

Wang, J.; Xiao, X.; Qin, Y.

2017-12-01

Woody plant encroachment into grasslands has been dominantly explained by fire suppression, grazing and CO2 concentrations in the atmosphere. As different root depths of grasses and trees in soils, increased precipitation intensity was expected to facilitate the woody plant abundance, which was demonstrated by the field precipitation test in a sub-tropical savanna ecosystem. However, it is lacking to compressively examine the roles of precipitation regimes on woody plant encroachment at regional scales based on long-term observation data. This study examined the relationships between changes of precipitation regimes (amounts, frequency and intensity) and dynamics of juniper forest coverage using site-based rainfall data and remote sensing-based juniper forest maps in 1994-2010 over Oklahoma State. Our results showed that precipitation amount and intensity played larger roles than frequency on the juniper forest encroachment into the grassland in Oklahoma, and increased precipitation amount and intensity could facilitate the juniper woody encroachment. This practice based on observation data at the regional scale could be used to support precipitation experiments and model simulations and predicting the juniper forest encroachment.

Encounters with Pinyon-Juniper influence riskier movements in Greater Sage-Grouse across the Great Basin

Science.gov (United States)

Prochazka, Brian; Coates, Peter S.; Ricca, Mark; Casazza, Michael L.; Gustafson, K. Ben; Hull, Josh M.

2016-01-01

Fine-scale spatiotemporal studies can better identify relationships between individual survival and habitat fragmentation so that mechanistic interpretations can be made at the population level. Recent advances in Global Positioning System (GPS) technology and statistical models capable of deconstructing high-frequency location data have facilitated interpretation of animal movement within a behaviorally mechanistic framework. Habitat fragmentation due to singleleaf pinyon (Pinus monophylla; hereafter pinyon) and Utah juniper (Juniperus osteosperma; hereafter juniper) encroachment into sagebrush (Artemisia spp.) communities is a commonly implicated perturbation that can adversely influence greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) demographic rates. Using an extensive GPS data set (233 birds and 282,954 locations) across 12 study sites within the Great Basin, we conducted a behavioral change point analysis and subsequently constructed Brownian bridge movement models from each behaviorally homogenous section. We found a positive relationship between modeled movement rate and probability of encountering pinyon-juniper with significant variation among age classes. The probability of encountering pinyon-juniper among adults was two and three times greater than that of yearlings and juveniles, respectively. However, the movement rate in response to the probability of encountering pinyon-juniper trees was 1.5 times greater for juveniles. We then assessed the risk of mortality associated with an interaction between movement rate and the probability of encountering pinyon-juniper using shared frailty models. During pinyon-juniper encounters, on average, juvenile, yearling, and adult birds experienced a 10.4%, 0.2%, and 0.3% reduction in annual survival probabilities. Populations that used pinyon-juniper habitats with a frequency ≥ 3.8 times the overall mean experienced decreases in annual survival probabilities of 71.1%, 0.9%, and 0.9%. This

Data set on the effects of conifer control and slash burning on soil carbon, total N, organic matter and extractable micro-nutrients

Directory of Open Access Journals (Sweden)

Jonathan D. Bates

2017-10-01

Full Text Available Conifer control in sagebrush steppe of the western United States causes various levels of site disturbance influencing vegetation recovery and resource availability. The data set presented in this article include growing season availability of soil micronutrients and levels of total soil carbon, organic matter, and N spanning a six year period following western juniper (Juniperus occidentalis spp. occidentalis reduction by mechanical cutting and prescribed fire of western juniper woodlands in southeast Oregon. These data can be useful to further evaluate the impacts of conifer woodland reduction to soil resources in sagebrush steppe plant communities.

Woodlands Grazing Issues in Mediterranean Basin

Science.gov (United States)

Campos, P.

2009-04-01

In Mediterranean basin, woodlands grazing still continue to be important commercial owners' benefits. These owners manage woodlands vegetations as if they were not at risk of degradation and declining. Frequently, no temporally grazing set-aside is taken into account to avoid overgrazing of annual and perennial vegetations. Although less common, in the northern shore of Mediterranean basin undergrazing might increase the frequency and the number of catastrophic forest fires. This under/over grazing regime occurs in the Mediterranean basin woodlands with contrasted differences on land property rights, local economies and government livestock policy incentives. Spain and Tunisia are examples of these Mediterranean livestock contrasts. Most of Spanish Mediterranean woodlands and livestock herds are large private ownerships and owners could maintain their lands and livestock herds properties on the basis of moderate cash-income compensation against land revaluation and exclusive amenity self-consumption. The later is less tangible benefit and it could include family land legacy, nature enjoyment, country stile of life development, social status and so on. In public woodlands, social and environmental goals -as they are cultural heritage, biodiversity loss mitigation, soil conservation and employment- could maintain market unprofitable woodlands operations. Last three decades Spanish Mediterranean woodlands owners have increased the livestock herds incentivized by government subsidies. As result, grazing rent is pending on the level of European Union and Spanish government livestock subsidies. In this context, Spanish Mediterranean woodlands maintain a high extensive livestock stoking population, which economy could be called fragile and environmentally unsustainable because forest degradation and over/under grazing practices. Tunisian Mediterranean woodlands are state properties and livestock grazing is practice as a free private regimen. Livestock herds are small herd

Spatial partitioning of water use by herbaceous and woody lifeforms in semiarid woodlands

International Nuclear Information System (INIS)

Breshears, D.D.

1993-01-01

Ecological studies of soil moisture, plant water uptake, and community composition in semiarid regions have focused on differences with depth in the soil profile, yet there are many reasons to expect that moisture also varies with the presence or absence of woody vegetation. Plant and soil moisture relationships for three dominant species in a semiarid woodland, Bouteloua gracilis, Juniperus monosperma, and Pinus edulis, were studied for 1.5 years. Soil moisture varied by type of plant cover as well as by depth. Plant water potential and conductance differed among species and was related to spatial variability in soil moisture. Water potential for blue grama was most correlated with soil moisture in the 0-15 cm layer of intercanopies; juniper water potential was highly correlated with soil moisture in the 0-15 cm layer beneath tree canopies of either species, and pinyon water potential was only weakly correlated with soil moisture in the 15-30 cm depth interval beneath pinyons. Pinyons had consistently greater maximum conductance rates than junipers, even though pinyon conductance was more sensitive to reductions in soil moisture. The results from this study indicate that horizontal differences in the soil moisture profile associated with type of plant cover may be as important as differences in depth for predicting plant-water relationships. A simple model was hypothesized for predicting community composition of three lifeforms: Herbaceous plants, shallow-rooted woody plants, and deeper-rooted woody plants. Distributions of roots of each lifeform and plant-available water were defined with respect to four soil compartments that distinguish upper vs. lower and canopy vs. intercanopy soil regions. The model predicts that multiple combinations of herbaceous and woody biomass can exist at a site and was qualitatively consistent with field data from a climatic gradient

Juniper Pollen Hotspots in the Southwest

Science.gov (United States)

Bunderson, L. D.; VandeWater, P.; Luvall, J.; Levetin, E.

2013-01-01

Rationale: Juniperus pollen is a major allergen in Texas, Oklahoma, and New Mexico. While the bulk of pollen may be released in rural areas, large amounts of pollen can be transported to urban areas. Major juniper species in the region include: Juniperus ashei, J. virginiana, J. pinchotii, and J. monosperma. Pollen release is virtually continuous beginning in late September with J. pinchotii and ending in May with J. monosperma. Urban areas in the region were evaluated for the potential of overlapping seasons in order to inform sensitive individuals. Methods: Burkard volumetric pollen traps were established for two consecutive spring seasons at 6 sites in northern New Mexico and 6 sites for two consecutive winter and fall seasons in Texas and Oklahoma Standard methods were used in the preparation and analysis of slides. Results: The Dallas-Fort Worth Metroplex is home to over 6 million people. It is adjacent to populations of J. pinchotii, J. virginiana, and J. ashei. Peak concentration near Dallas for J. ashei in 2011 was 5891 pollen grains/m3 in January 7th. The peak date for J. pinchotii at an upwind sampling location in San Marcos, TX was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was February 20, 2011. Amarillo, TX is adjacent to J. pinchotii, J. ashei, and J. monosperma populations and may be subject to juniper pollen from September through May. Conclusions: Considering the overlapping distributions of juniper trees and the overlapping temporal release of pollen, sensitive patients may benefit from avoiding hotspots.

Distribution of western juniper seeds across an ecotone and implications for seed dispersal processes

Science.gov (United States)

Western juniper forests have been the focus of extensive research and management due to range expansion and infilling that began over a century ago. Understanding juniper seed dispersal is vital to identifying processes behind increases in density and range. Dispersal of Juniperus seeds has generall...

Variation in herbaceous vegetation and soil moisture under treated and untreated oneseed juniper trees

Science.gov (United States)

Hector Ramirez; Alexander Fernald; Andres Cibils; Michelle Morris; Shad Cox; Michael Rubio

2008-01-01

Clearing oneseed juniper (Juniperus monosperma) may make more water available for aquifer recharge or herbaceous vegetation growth, but the effects of tree treatment on soil moisture dynamics are not fully understood. This study investigated juniper treatment effects on understory herbaceous vegetation concurrently with soil moisture dynamics using vegetation sampling...

Effectiveness of prescribed fire to re-establish sagebrush vegetation and ecohydrologic function on woodland-encroached sagebrush steppe, Great Basin, USA

Science.gov (United States)

Williams, C. J.; Pierson, F. B.; Kormos, P.; Al-Hamdan, O. Z.; Nouwakpo, S.; Weltz, M.; Vega, S.; Lindsay, K.

2017-12-01

Range expansion of pinyon (Pinus spp.) and juniper (Juniperus spp.) conifers into sagebrush steppe (Artemisia spp.) communities has imperiled a vast domain in the western US. Encroachment of sagebrush ecosystems by pinyon and juniper conifers has negative ramifications to ecosystem structure and function and delivery of goods and services. Scientists, land management agencies, and private land owners throughout the western US are challenged with selecting from a suite of options to reduce pinyon and juniper woody fuels and re-establish sagebrush steppe structure and function. This study evaluated the effectiveness of prescribed fire to re-establish sagebrush vegetation and ecohydrologic function over a 9 yr period. Nine years post-fire hydrologic and erosion responses reflect the combination of pre-fire site conditions, perennial grass recruitment, delayed litter cover, and inherent site characteristics. Burning initially increased bare ground, runoff, and erosion for well-vegetated areas underneath tree and shrub canopies, but had minimal impact on hydrology and erosion for degraded interspaces between plants. The degraded interspaces were primarily bare ground and exhibited high runoff and erosion rates prior to burning. Initial fire effects persisted for two years, but increased productivity of grasses improved hydrologic function of interspaces over the full 9 yr period. At the hillslope scale, grass recruitment in the intercanopy between trees reduced runoff from rainsplash, sheetflow, and concentrated overland flow at one site, but did not reduce the high levels of runoff and erosion from a more degraded site. In areas formerly occupied by trees (tree zones), burning increased invasive annual grass cover due to fire removal of limited native perennial plants and competition for resources. The invasive annual grass cover had no net effect on runoff and erosion from tree zones however. Runoff and erosion increased in tree zones at the more degraded site due to

Conflicting short and long-term management goals: Fire effects in endangered golden-cheeked warbler (Setophaga chrysoparia) habitat

Science.gov (United States)

Christina M. Andruk; Norma L. Fowler

2015-01-01

Decades of fire suppression have significantly altered the vegetation structure and composition of savannas, woodlands, and forests. The presence of endangered species and other species of conservation concern in these fire-suppressed systems makes re-introducing fire more challenging. In oak-juniper woodlands of central Texas, we are presented with the challenge of re...

Fuel-wood from undermanaged woodland

Energy Technology Data Exchange (ETDEWEB)

Landen, R A

1995-11-22

This report examines the potential for the utilisation of currently undermanaged woodland for supply of wood fuel. The potential markets for wood fuel are identified, along with their requirements in terms of fuel specification. Woodland resources currently receiving little or no management are identified, concentrating on broadleaves in lowland Britain. The nature of these resources is discussed, and opportunities/constraints for their management reviewed. Machinery suitable for these woodland areas is discussed, and the application of this equipment into practical systems is examined in some detail. These themes are developed in two case studies, resulting in a discussion of findings and a range of conclusions. It is believed that potential exists to extract chipped wood fuel form existing unmanaged woodland areas from Pound 25/gt upwards, including standing value and contractor profit. (Author)

Restoration of mountain big sagebrush steppe following prescribed burning to control western juniper.

Science.gov (United States)

Davies, K W; Bates, J D; Madsen, M D; Nafus, A M

2014-05-01

Western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroachment into mountain big sagebrush (Artemisia tridentata spp. vaseyana (Rydb.) Beetle) steppe has reduced livestock forage production, increased erosion risk, and degraded sagebrush-associated wildlife habitat. Western juniper has been successfully controlled with partial cutting followed by prescribed burning the next fall, but the herbaceous understory and sagebrush may be slow to recover. We evaluated the effectiveness of seeding perennial herbaceous vegetation and sagebrush at five sites where juniper was controlled by partially cutting and prescribed burning. Treatments tested at each site included an unseeded control, herbaceous seed mix (aerially seeded), and the herbaceous seed mix plus sagebrush seed. In the third year post-treatment, perennial grass cover and density were twice as high in plots receiving the herbaceous seed mix compared to the control plots. Sagebrush cover and density in the sagebrush seeded plots were between 74- and 290-fold and 62- and 155-fold greater than the other treatments. By the third year after treatment, sagebrush cover was as high as 12 % in the sagebrush seeded plots and between 0 % and 0.4 % where it was not seeded. These results indicate that aerial seeding perennial herbaceous vegetation can accelerate the recovery of perennial grasses which likely stabilize the site. Our results also suggest that seeding mountain big sagebrush after prescribed burning encroaching juniper can rapidly recover sagebrush cover and density. In areas where sagebrush habitat is limited, seeding sagebrush after juniper control may increase sagebrush habitat and decrease the risks to sagebrush-associated species.

Factors influencing woodlands of southwestern North Dakota

Science.gov (United States)

Michele M. Girard; Harold Goetz; Ardell J. Bjugstad

1987-01-01

Literature pertaining to woodlands of southwestern North Dakota is reviewed. Woodland species composition and distribution, and factors influencing woodland ecosystems such as climate, logging, fire, and grazing are described. Potential management and improvement techniques using vegetation and livestock manipulation have been suggested.

Foliar carbon dynamics of piñon and juniper in response to experimental drought and heat

Science.gov (United States)

Collins, A.; Ryan, M. G.; Adams, H. D.; Dickman, L. T.; Garcia-Forner, N.; Grossiord, C.; Powers, H. H.; Sevanto, S.; McDowell, N. G.

2015-12-01

Plant respiration (R) is generally well-coupled with temperature and in the absence of thermal acclimation, respiration is expected to increase as climate change brings higher temperatures. Increased drought is also predicted for future climate, which could drive respiration higher if the carbon (C) cost to maintain tissues (Rm) or grow increases, or lower if substrate or other factors become limiting. We examined the effects of temperature and drought on R as well as photosynthesis, growth, and carbohydrate storage of mature individuals of two co-dominant tree species. Three mature, in-situ piñon (Pinus edulis) and juniper (Juniperus monosperma) trees were assigned to each of the following treatments: +4.8 °C; 45% reduced precipitation; a combination of both (heat + drought); along with ambient control and treatment controls. Rm measured prior to foliar and twig growth was far more sensitive to drought in piñon, and heat in juniper. Total respiration (Rt, R not partitioned) acclimated to temperature in piñon such that elevated temperature had minimal impacts on Rt; however, juniper exhibited higher Rt with elevated temperature, thus juniper did not display any thermal acclimation. Rt in both species was weakly associated with temperature, but strongly correlated with pre-dawn water potential, photosynthetic assimilation (A) rates, and in piñon, foliar carbohydrates. For both species, heat caused far more days where A-R was negative than did drought. The consequences of drought alone and heat alone in piñon included higher Rt per unit growth, indicating that each abiotic stress forces a greater allocation of Rt to maintenance costs, and both drought + heat in combination results in far fewer days that foliar carbohydrates could sustain R in both species. Notably, the much higher A and R of juniper than piñon is consistent with predicted superior carbon budget regulation of juniper than piñon during drought; however, juniper's lack of temperature acclimation

Genetic analysis of interacting trophic levels in a stressed pinyon-juniper community: A model for examining community responses to a rapid and recent environmental changes. Final report, May 1, 1994--April 30, 1997

Energy Technology Data Exchange (ETDEWEB)

Keim, P.; Whithmam, T.; Cobb, N.; Gehring, C.

1998-05-01

The goals of this project were to examine the genetic component of a pinyon-juniper woodland that had recently experienced a dramatic environmental change. The environmental change was increased temperature and decreased water associated with the volcanic cinder field at Sunset Crater National Monument. In all of these experiments we have used adjacent soil sites as controls for the effects of the stressed locations. We have examined mycorrhizal colonization and diversity in order to understand this important component in community {open_quotes}adaptation{close_quotes} to climate change. We have examined genetic diversity in the pinyon pine populations to determine what level of genetic differentiation has occurred between stressed and nonstressed locations. In addition, we have recently expanded our environmental parameters to include elevated CO{sub 2} on mycorrhizal performance and diversity.

75 FR 18201 - Juniper Canyon Wind Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

Science.gov (United States)

2010-04-09

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER10-975-000] Juniper Canyon Wind Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... of Juniper Canyon Wind Power, LLC's application for market-based rate authority, with an accompanying...

Farmers' objectives toward their woodlands in the upper Midwest of the United States: implications for woodland volumes and diversity

Science.gov (United States)

W. Keith Moser; Earl C. Leatherberry; Mark H. Hansen; Brett J. Butler

2009-01-01

This paper reports the results of a study that explores the relationship between farm woodland owners' stated intentions for owning woodland, and the structure and composition of these woodlands in the states of Illinois, Indiana and Iowa in the upper Midwest of the United States. Data from two sample-based inventories conducted by the USDA Forest Service, Forest...

Optimizing Emory oak woodlands for multiple resource benefits [Poster

Science.gov (United States)

Catlow Shipek; Peter F. Ffolliott; Gerald J. Gottfried; Leonard F. DeBano

2005-01-01

The Emory oak woodlands in the southwestern United States present a diverse range of resources. People utilize these woodlands for wood products, cattle grazing, and recreational purposes. The woodlands provide a diversity of wildlife habitats for resident and migratory species. Occupying predominantly upland regions, the oak woodlands protect watersheds from excessive...

Impact of grazing abandonment on floristic diversity in the priority habitat type *9562 Grecian Juniper Woods

Science.gov (United States)

Vrahnakis, Michael; Kazoglou, Yannis; Fotiadis, George; Kakouros, Petros; Nasiakou, Stamatia; Soutsas, Konstantinos

2017-04-01

The habitat type *9562 Grecian juniper woods (Juniperetum excelsae) includes Greek juniper (Juniperus excelsa M. Bieb.) forests and they are found mainly in the western sector of the Prespa National Park, NW Greece. Greek juniper forests are considered extremely rare for EU-28, recommending a priority habitat type in accordance with Directive 92/43/EEC. In addition, their ecological importance is great given its high plant taxa richness; they harbor most of the 900 plant taxa found in the western sector of the Park, many of them being important for EU or global scale. The accelerated invasion of deciduous hardwoods is the most significant risk for the habitat, since its rich flora is well-adapted to open light conditions produced by the open spaced Greek junipers. Also, the dense vegetated conditions deprive the regeneration of the photophilous Greek juniper. The invasion results from the lack of its natural controller, i.e. the grazing livestock. It is estimated that the total area of juniper forests for the Devas area decreased to 89% of the area of 1945 in favor of invasive hardwoods. The paper presents the analysis of the floristic diversity of the priority habitat type *9562 Grecian Juniper Woods (Juniperetum excelsae) (GJWs). Four (4) types of juniper forest ranges (GJWs) were distinguished in terms of canopy cover: (a) pure GJWs, (b) mixed open GJWs, (c) open GJWs, and (d) mixed dense GJWs. A total of 171 plant taxa were recorded, and distributed within 43 botanical families; the largest one being Leguminosae (26 taxa). The statistically estimated plant taxa richness for pure GJWs was 116.4, for mixed open 152.6, for open 57.9, and for mixed dense 90.2 taxa. The analysis of α-diversity indices did not reveal any specific trend of diversity for the four GJWs. The behavior of the variability of diversity among the four range types of GJWs was depending on the emphasis the used indices place on properties such as taxa richness or abundance. This fact was

Linking ecosystem scale vegetation change to shifts in carbon and water cycling: the consequences of widespread piñon mortality in the Southwest

Energy Technology Data Exchange (ETDEWEB)

Litvak, Marcy Ellen [University of New Mexico

2012-10-01

The southwestern United States experienced an extended drought from 1999-2002 which led to widespread coniferous tree mortality. Piñon-juniper (PJ) woodlands, which occupy 24 million ha throughout the Southwest, were extremely vulnerable to this drought. An abrupt die-off of 40 to 95% of piñon pine (Pinus edulis) and 2-25% of juniper (Juniperus monosperma) across 1.5 million ha triggered rapid and extensive changes in the structure of PJ woodlands with potentially large, yet unknown, consequences for ecosystem services and feedbacks between the carbon cycle and climate system. Given the spatial extent of PJ woodlands (3rd largest biome in the US) and climatic predictions of increased frequency and intensity of drought in the region, it is crucial to understand the consequences of these disturbances on regional carbon and energy dynamics, biogeochemical processes and atmospheric CO2. The overall objective of our research was to quantify what impact widespread mortality of piñon trees has for carbon and water cycling in PJ woodlands. Our specific objectives for this proposal were: 1) Quantify the carbon, water and energy exchange trajectory after mortality in PJ woodlands; 2) Determine the mechanisms controlling the response and recovery of ecosystem production and respiration processes following large-scale piñon mortality; 3) Use the relationships we measure between ecosystem structure and function PJ woodlands recover from mortality to scale the results of our study up to the regional scale.

Purple martins in oak woodlands

Science.gov (United States)

Brian D. C. Williams

2002-01-01

Purple martins are cavity-nesting swallows that once nested fairly widely in California’s oak woodlands but are now rare in that habitat. The old oaks of the Tehachapi Range (southern Sierra Nevada) may now host the last martins that nest in oak woodlands, with approximately 100-200 pairs or about 15 percent of the California population. In summer of 2000, we found 57...

Proceedings of the western juniper ecology and management workshop.

Science.gov (United States)

Robert E. Martin; J. Edward Dealy; David L. Caraher

1977-01-01

Western juniper (Juniperus occidentalis subsp. occidentalis) is an important invader of range lands in central and eastern Oregon. Many people have asked questions about its control, effect on range productivity, and its benefits. The papers in this proceedings resulted from a conference held in Bend, Oregon, January 1977, to...

On the detection of thermohygrometric differences of Juniperus turbinata habitat between north and south faces in the island of El Hierro (Canary Islands)

Science.gov (United States)

Salva-Catarineu, Montserrat; Salvador-Franch, Ferran; Lopez-Bustins, Joan A.; Padrón-Padrón, Pedro A.; Cortés-Lucas, Amparo

2016-04-01

The current extent of Juniperus turbinata in the island of El Hierro is very small due to heavy exploitation for centuries. The recovery of its natural habitat has such a high environmental and scenic interest since this is a protected species in Europe. The study of the environmental factors that help or limit its recovery is indispensable. Our research project (JUNITUR) studied the populations of juniper woodlands in El Hierro from different environments. These environments are mainly determined by their altitude and exposure to north-easterly trade winds. The main objective of this study was to compare the thermohygrometric conditions of three juniper woodlands: La Dehesa (north-west face at 528 m a.s.l.), El Julan (south face at 996 m a.s.l.) and Sabinosa (north face at 258 m a.s.l.). They are located at different altitude and orientation in El Hierro and present different recovery rates. We used air sensor data loggers fixed to tree branches for recording hourly temperature and humidity data in the three study areas. We analysed daily data of three annual cycles (from September 2012 to August 2015). Similar thermohygrometric annual cycles among the three study areas were observed. We detected the largest differences in winter temperature and summer humidity between the north (to windward) (Sabinosa and La Dehesa) and south (to leeward) (El Julan) faces of the island. The juniper woodland with a highest recovery rate (El Julan) showed the most extreme temperature conditions in both winter and summer seasons. The results of this project might contribute to the knowledge of the juniper bioclimatology in El Hierro, where there is the biggest population of Juniperus turbinata throughout the Canary Islands.

Ecosystem water availability in juniper versus sagebrush snow-dominated rangelands

Science.gov (United States)

Western Juniper (J. occidentalis Hook.) now dominates over 3.6 million ha of rangeland in the Intermountain Western US. Critical ecological relationships among snow distribution, water budgets, plant community transitions, and habitat requirements for wildlife, such as sage grouse, remain poorly und...

Fragmentation patterns of evergreen oak woodlands in Southwestern Iberia

DEFF Research Database (Denmark)

Costa, A.; Madeira, M.; Lima Santos, J.

2014-01-01

Mediterranean evergreen oak woodlands (composed of Quercus suber L. and Quercus rotundifolia Lam.) are becoming increasingly fragmented in the human-modified landscapes of Southwestern Portugal and Spain. Previous studies have largely neglected to assess the spatial changes of oak woodlands...... patterns of oak recruitment and therefore, its study may be helpful in highlighting future baselines for the sustainable management of oak woodlands....

Visual aspects in urban woodland management and planning

OpenAIRE

Ode, Åsa

2003-01-01

Urban woodland is an important component of people's everyday environment, both as an attractive environment to visit as well as being an intrinsic part of the surrounding landscape. This thesis focuses on one specific aspect of the urban woodland - the visual. The visual aspect is how most people experience the woodland, both when visiting and as part of their everyday landscape. In order to take visual aspects into account there is a need to have tools and approaches for analysing and descr...

Predicted fire behavior and societal benefits in three eastern Sierra Nevada vegetation types

Science.gov (United States)

C.A. Dicus; K. Delfino; D.R. Weise

2009-01-01

We investigated potential fire behavior and various societal benefits (air pollution removal, carbon sequestration, and carbon storage) provided by woodlands of pinyon pine (Pinus monophylla) and juniper (Juniperus californica), shrublands of Great Basin sagebrush (Artemisia tridentata) and rabbitbrush (Ericameria nauseosa...

Tracking juniper berry content in oils and distillates by spectral deconvolution of gas chromatography/mass spectrometry data.

Science.gov (United States)

Robbat, Albert; Kowalsick, Amanda; Howell, Jessalin

2011-08-12

The complex nature of botanicals and essential oils makes it difficult to identify all of the constituents by gas chromatography/mass spectrometry (GC/MS) alone. In this paper, automated sequential, multidimensional gas chromatography/mass spectrometry (GC-GC/MS) was used to obtain a matrix-specific, retention time/mass spectrometry library of 190 juniper berry oil compounds. GC/MS analysis on stationary phases with different polarities confirmed the identities of each compound when spectral deconvolution software was used to analyze the oil. Also analyzed were distillates of juniper berry and its oil as well as gin from four different manufacturers. Findings showed the chemical content of juniper berry can be traced from starting material to final product and can be used to authenticate and differentiate brands. Copyright © 2011 Elsevier B.V. All rights reserved.

Influencing woodland management using web-based technology

Science.gov (United States)

William R. Thomas; Jeffrey W. Stringer

2011-01-01

The University of Kentucky, Department of Forestry Extension delivered hosted Web-based forestry educational programs ("webinars") in 2009 to promote woodland management in Kentucky and engage county extension agents in forestry programming. These webinars were hosted by county extension agents and attended by woodland owners. This hosted webinar approach was...

Historical and modern disturbance regimes, stand structures, and landscape dynamics in pinyon-juniper vegetation of the Western U.S.

Science.gov (United States)

William H. Romme; Craig D. Allen; John D. Bailey; William L. Baker; Brandon T. Bestelmeyer; Peter M. Brown; Karen S. Eisenhart; M. Lisa Floyd; David W. Huffman; Brian F. Jacobs; Richard F. Miller; Esteban H. Muldavin; Thomas W. Swetnam; Robin J. Tausch; Peter J. Weisberg

2009-01-01

Pinon-juniper is a major vegetation type in western North America. Effective management of these ecosystems has been hindered by inadequate understanding of 1) the variability in ecosystem structure and ecological processes that exists among the diverse combinations of Pinons, junipers, and associated shrubs, herbs, and soil organisms; 2) the prehistoric and historic...

Variation in woody plant mortality and dieback from severe drought among soils, plant groups, and species within a northern Arizona ecotone.

Science.gov (United States)

Koepke, Dan F; Kolb, Thomas E; Adams, Henry D

2010-08-01

Vegetation change from drought-induced mortality can alter ecosystem community structure, biodiversity, and services. Although drought-induced mortality of woody plants has increased globally with recent warming, influences of soil type, tree and shrub groups, and species are poorly understood. Following the severe 2002 drought in northern Arizona, we surveyed woody plant mortality and canopy dieback of live trees and shrubs at the forest-woodland ecotone on soils derived from three soil parent materials (cinder, flow basalt, sedimentary) that differed in texture and rockiness. Our first of three major findings was that soil parent material had little effect on mortality of both trees and shrubs, yet canopy dieback of trees was influenced by parent material; dieback was highest on the cinder for pinyon pine (Pinus edulis) and one-seed juniper (Juniperus monosperma). Ponderosa pine (Pinus ponderosa) dieback was not sensitive to parent material. Second, shrubs had similar mortality, but greater canopy dieback, than trees. Third, pinyon and ponderosa pines had greater mortality than juniper, yet juniper had greater dieback, reflecting different hydraulic characteristics among these tree species. Our results show that impacts of severe drought on woody plants differed among tree species and tree and shrub groups, and such impacts were widespread over different soils in the southwestern U.S. Increasing frequency of severe drought with climate warming will likely cause similar mortality to trees and shrubs over major soil types at the forest-woodland ecotone in this region, but due to greater mortality of other tree species, tree cover will shift from a mixture of species to dominance by junipers and shrubs. Surviving junipers and shrubs will also likely have diminished leaf area due to canopy dieback.

Determine the optimum spectral reflectance of juniper and pistachio in arid and semi-arid region

Science.gov (United States)

Fadaei, Hadi; Suzuki, Rikie

2012-11-01

Arid and semi-arid areas of northeast Iran cover about 3.4 million ha are populated by two main tree species, the broadleaf Pistacia vera. L (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but genetically essential as seed sources for pistachio production in orchards. In this study, we estimated the optimum spectral reflectance of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. In this research spectral reflectance are able to specify of multispectral from Advanced Land Observing Satellite (ALOS) that provided by JAXA. These data included PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, has one band with a wavelength of 0.52-0.77 μm and AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm). Total ratio vegetation index (TRVI) of optimum spectral reflectance of juniper and pistachio have been evaluated. The result of TRVI for Pistachio and juniper were (R2= 0.71 and 0.55). I hope this research can provide decision of managers to helping sustainable management for arid and semi-arid regions in Iran.

Impacts of an Extreme Early-Season Freeze Event in the Interior Pacific Northwest (30 October-3 November 2002) on Western Juniper Woodlands.

Science.gov (United States)

Knapp, Paul A.; Soulé, Peter T.

2005-07-01

In mid-autumn 2002, an exceptional 5-day cold spell affected much of the interior Pacific Northwest, with minimum temperatures averaging 13°C below long-term means (1953-2002). On 31 October, minimum temperature records occurred at 98 of the 106 recording stations, with records lowered in some locations by 9°C. Calculation of recurrence intervals of minimum temperatures shows that 50% of the stations experienced a >500-yr event. The synoptic conditions responsible were the development of a pronounced high pressure ridge over western Canada and an intense low pressure area centered in the Intermountain West that promoted strong northeasterly winds. The cold spell occurred near the end of the growing season for an ecologically critical and dominant tree species of the interior Pacific Northwest—western juniper—and followed an extended period of severe drought. In spring 2003, it became apparent that the cold had caused high rates of tree mortality and canopy dieback in a species that is remarkable for its longevity and resistance to climatic stress. The cold event altered western juniper dominance in some areas, and this alteration may have long-term impacts on water budgets, fire intensities and frequencies, animal species interrelationships, and interspecific competition among plant species.

Fragmentation patterns of evergreen oak woodlands in Southwestern Iberia: identifying key spatial indicators.

Science.gov (United States)

Costa, Augusta; Madeira, Manuel; Lima Santos, José; Plieninger, Tobias; Seixas, Júlia

2014-01-15

Mediterranean evergreen oak woodlands (composed of Quercus suber L. and Quercus rotundifolia Lam.) are becoming increasingly fragmented in the human-modified landscapes of Southwestern Portugal and Spain. Previous studies have largely neglected to assess the spatial changes of oak woodlands in relation to their surrounding landscape matrix, and to characterize and quantify woodland boundaries and edges. The present study aims to fill this gap by analyzing fragmentation patterns of oak woodlands over a 50-year period (1958-2007) in three landscapes. Using archived aerial imagery from 1958, 1995 and 2007, for two consecutive periods (1958-1995 and 1995-2007), we calculated a set of landscape metrics to compare woodland fragmentation over time. Our results indicated a continuous woodland fragmentation characterized by their edge dynamics. From 1958 to 2007, the replacement of open farmland by shrubland and by new afforestation areas in the oak woodland landscape surrounding matrix, led to the highest values for edge contrast length trends of 5.0 and 12.3, respectively. Linear discriminant analysis was performed to delineate fragmented woodland structures and identify metric variables that characterize woodland spatial configuration. The edge contrast length with open farmland showed a strong correlation with F1 (correlations ranging between 0.55 and 0.98) and may be used as a proxy for oak woodland mixedness in landscape matrix. The edge dynamics of oak woodlands may result in different patterns of oak recruitment and therefore, its study may be helpful in highlighting future baselines for the sustainable management of oak woodlands. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydrologic control of the oxygen isotope ratio of ecosystem respiration in a semi-arid woodland

Directory of Open Access Journals (Sweden)

J. H. Shim

2013-07-01

Full Text Available We conducted high frequency measurements of the δ18O value of atmospheric CO2 from a juniper (Juniperus monosperma woodland in New Mexico, USA, over a four-year period to investigate climatic and physiological regulation of the δ18O value of ecosystem respiration (δR. Rain pulses reset δR with the dominant water source isotope composition, followed by progressive enrichment of δR. Transpiration (ET was significantly related to post-pulse δR enrichment because the leaf water δ18O value showed strong enrichment with increasing vapor pressure deficit that occurs following rain. Post-pulse δR enrichment was correlated with both ET and the ratio of ET to soil evaporation (ET/ES. In contrast, the soil water δ18O value was relatively stable and δR enrichment was not correlated with ES. Model simulations captured the large post-pulse δR enrichments only when the offset between xylem and leaf water δ18O value was modeled explicitly and when a gross flux model for CO2 retro-diffusion was included. Drought impacts δR through the balance between evaporative demand, which enriches δR, and low soil moisture availability, which attenuates δR enrichment through reduced ET. The net result, observed throughout all four years of our study, was a negative correlation of post-precipitation δR enrichment with increasing drought.

Resent state and multivariate analysis of a few juniper forests of baluchistan, pakistan

International Nuclear Information System (INIS)

Ahmed, M.; Siddiqui, M.F.

2015-01-01

Quantitative multivariate investigations were carried out to explore various forms of Juniper trees resulting human disturbances and natural phenomenon. Thirty stands were sampled by point centered quarter method and data were analysed using Wards cluster analysis and Bray-Curtis ordination. On the basis of multivariate analysis eight various forms i.e. healthy, unhealthy, over mature, disturbed, dieback, standing dead, logs and cut stem were recognized. Structural attributes were computed. Highest numbers (130-133 stem ha-1) of logs were recorded from Cautair and Khunk forests. Highest density ha-1 (229 ha-1) of healthy plants was estimated from Tangi Top area while lowest number (24 ha-1) of healthy plants was found from Saraghara area. Multivariate analysis showed five groups in cluster and ordination diagrams. These groups are characterized on the basis of healthy, over mature, disturbed and logged trees of Juniper. Higher number (115, 96, 84, 80 ha-1) of disturbed trees were distributed at Speena Sukher, Srag Kazi, Prang Shella and Tangi Top respectively. Overall density does not show any significant relation with basal area m2 ha-1, degree of slopes and the elevation of the sampling stands. Present study show that each and every Juniper stands are highly disturbed mostly due to human influence, therefore prompt conservational steps should be taken to safe these forests. (author)

The Oak Woodland Bird Conservation Plan: A Strategy for Protecting and Managing Oak Woodland Habitats and Associated Birds in California

Science.gov (United States)

Steve Zack; Mary K. Chase; Geoffrey R. Geupel; Diana Stralberg

2005-01-01

Over 330 species of birds, mammals, reptiles, and amphibians depend on oak woodlands in California (fig. 1) at some stage in their life cycle (Barrett 1980; Verner 1980; Block and Morrison 1998). These woodlands are able to sustain such abundant wildlife primarily because they produce acorns, a high quality and frequently copious food supply. The birds of California?s...

Viewpoint: Sustainability of piñon-juniper ecosystems - A unifying perspective of soil erosion thresholds

Science.gov (United States)

Davenport, David W.; Breshears, D.D.; Wilcox, B.P.; Allen, Craig D.

1998-01-01

Many pinon-juniper ecosystem in the western U.S. are subject to accelerated erosion while others are undergoing little or no erosion. Controversy has developed over whether invading or encroaching pinon and juniper species are inherently harmful to rangeland ecosystems. We developed a conceptual model of soil erosion in pinon-jumper ecosystems that is consistent with both sides of the controversy and suggests that the diverse perspectives on this issue arise from threshold effects operating under very different site conditions. Soil erosion rate can be viewed as a function of (1) site erosion potential (SEP), determined by climate, geomorphology and soil erodibility; and (2) ground cover. Site erosion potential and cove act synergistically to determine soil erosion rates, as evident even from simple USLE predictions of erosion. In pinon-juniper ecosystem with high SEP, the erosion rate is highly sensitive to ground cover and can cross a threshold so that erosion increases dramatically in response to a small decrease in cover. The sensitivity of erosion rate to SEP and cover can be visualized as a cusp catastrophe surface on which changes may occur rapidly and irreversibly. The mechanisms associated with a rapid shift from low to high erosion rate can be illustrated using percolation theory to incorporate spatial, temporal, and scale-dependent patterns of water storage capacity on a hillslope. Percolation theory demonstrates how hillslope runoff can undergo a threshold response to a minor change in storage capacity. Our conceptual model suggests that pinion and juniper contribute to accelerated erosion only under a limited range of site conditions which, however, may exist over large areas.

Economic incentives for oak woodland preservation and conservation

Science.gov (United States)

Rosi Dagit; Cy Carlberg; Christy Cuba; Thomas Scott

2015-01-01

Numerous ordinances and laws recognize the value of oak trees and woodlands, and dictate serious and expensive consequences for removing or harming them. Unfortunately, the methods used to calculate these values are equally numerous and often inconsistent. More important, these ordinances typically lack economic incentives to avoid impacts to oak woodland values...

Mapping Woodland Cover in the Miombo Ecosystem: A Comparison of Machine Learning Classifiers

Directory of Open Access Journals (Sweden)

Courage Kamusoko

2014-06-01

Full Text Available Miombo woodlands in Southern Africa are experiencing accelerated changes due to natural and anthropogenic disturbances. In order to formulate sustainable woodland management strategies in the Miombo ecosystem, timely and up-to-date land cover information is required. Recent advances in remote sensing technology have improved land cover mapping in tropical evergreen ecosystems. However, woodland cover mapping remains a challenge in the Miombo ecosystem. The objective of the study was to evaluate the performance of decision trees (DT, random forests (RF, and support vector machines (SVM in the context of improving woodland and non-woodland cover mapping in the Miombo ecosystem in Zimbabwe. We used Multidate Landsat 8 spectral and spatial dependence (Moran’s I variables to map woodland and non-woodland cover. Results show that RF classifier outperformed the SVM and DT classifiers by 4% and 15%, respectively. The RF importance measures show that multidate Landsat 8 spectral and spatial variables had the greatest influence on class-separability in the study area. Therefore, the RF classifier has potential to improve woodland cover mapping in the Miombo ecosystem.

Vegetation structure and small-scale pattern in Miombo Woodland, Marondera, Zimbabwe

Directory of Open Access Journals (Sweden)

B. M. Campbell

1995-10-01

Full Text Available The aim ol this paper is to describe woodland structure and small-scale patterning of woody plants at a miombo site, and to relate these to past disturbance and soil properties. Brachystegia spiciformis Benth. and Julbemardia globiflora (Benth. Troupin were the most frequent woody plants at the five hectare site, with size-class distributions which were markedly skewed towards the smaller size classes. The vegetation structure at the site and the increase in basal area over the past thirty years point to considerable disturbance prior to the present protected status. Six woodland subtypes were identified, grouped into two structural types: open and closed woodland. The distribution of woodland subtypes related closely to certain soil properties. It was hypothesized that the distribution of open and closed woodland is stable and a positive feedback mechanism by which this occurs is postulated.

Migration of vascular plant species to a recent wood adjoining ancient woodland

Directory of Open Access Journals (Sweden)

Zbigniew Dzwonko

2014-01-01

Full Text Available Woodland communities can be restored by natural succession in sites adjoining ancient woodlands which can act as seed sources for trees, shrubs and woodland herbs. The influence of dominant tree species and the distance from an adjacent ancient oak-hornbeam woodland upon the floristic composition of species in a recent pine wood planted on dry rendzina soil were studied. It was found that, in spite of a 52-year long succession, the border between woods was sharp and the composition of species in the recent wood were significantly different than in the adjacent ancient woodland. Canonical correspondence analysis (CCA showed that the distance to the ancient woodland had a significant influence on species distributions in the recent wood. The numbers of species from the Querco-Fagetea class, vegetatively reproducing species and myrmecochores decreased with this distance, whereas the numbers of anemochores increased. The migration rate of many woodland species, calculated on occurrence of the farthest individuals was very slow, varying from 0.0 m year-1 to 0.38 m year-1. The restoration of the field layer vegetation in the studied pine wood was much slower than in recent deciduous woods on rich and moist soils where the migration rate of some species exceeded 1.50 m year-1. Recent woods adjacent to ancient woodlands can be more effectively colonised by woodland species only when they are dominated by broad-leaved trees with quickly decomposing litter, and the spatial continuity of these woods persists for a long period.

Woodland as working space: where is the restorative green idyll?

Science.gov (United States)

Bingley, Amanda

2013-08-01

Much has been written on the beneficial, restorative qualities of 'natural' (non-built) rural or urban 'green' space, including woodland, in promoting mental and physical health when accessed for leisure, sport and education. In contrast, with the exception of rural health studies, there is relatively little debate about the health benefits of 'green space' as work place, especially in woodland and forests. In the developed world, this apparent gap in the literature may be partly due to an assumption of the forest work place as inherently healthy, and also the invisibility of a tiny percentage of the workforce now employed in forestry. However, in the UK and parts of Europe over recent years there has been a small, though significant, increase in opportunities to train and work in woodlands using traditional, sustainable management such as coppicing, and an exploration of health issues of woodland work is timely. This paper reports on findings from a secondary narrative analysis of oral history interviews selected from two phases of the Woodland Recollections Project and newsletters written by local people historically and currently engaged in coppicing and woodland work in North West England. Perceptions of healthy working in green space are examined by applying key concepts of Attention Restoration Theory (ART). Findings suggest that woodland work environments involve many counter-restorative factors that can render the 'green idyll' detrimental to health and wellbeing. To benefit from restorative elements requires drawing on a high level of specialist skills that empower individuals to manage and maintain healthy working practices in these diverse and challenging environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluating theories of drought-induced vegetation mortality using a multimodel-experiment framework

Science.gov (United States)

Nate G. McDowell; Rosie A. Fisher; Chonggang Xu; J. C. Domec; Teemu Holtta; D. Scott Mackay; John S. Sperry; Amanda Boutz; Lee Dickman; Nathan Gehres; Jean Marc Limousin; Alison Macalady; Jordi Martinez-Vilalta; Maurizio Mencuccini; Jennifer A. Plaut; Jerome Ogee; Robert E. Pangle; Daniel P. Rasse; Michael G. Ryan; Sanna Sevanto; Richard H. Waring; A. Park Williams; Enrico A. Yepez; William T. Pockman

2013-01-01

Model-data comparisons of plant physiological processes provide an understanding of mechanisms underlying vegetation responses to climate. We simulated the physiology of a pinon pine-juniper woodland (Pinus edulis-Juniperus monosperma) that experienced mortality during a 5 yr precipitation-reduction experiment, allowing a framework with which to examine our knowledge...

Use of saltcedar and Utah juniper as fillers in wood–plastic composites

Science.gov (United States)

Craig Clemons; Nicole Stark

2007-01-01

Invasive and small-diameter species have become more prevalent, creating numerous environmental and ecological problems. One potential method to control and eliminate invasive species and thereby promote natural rangeland restoration is developing new, value-added uses for them. Saltcedar (Tamarisk ramosissima) and Utah juniper (Juniperus osteosperma) were investigated...

Environmental, genetic, and ecophysiological variation of western and Utah juniper and their hybrids: A model system for vegetation response to climate change. Final report

Energy Technology Data Exchange (ETDEWEB)

Nowak, R.S. [Univ. of Nevada, Reno, NV (United States). Dept. of Environmental and Resource Sciences; Tausch, R.J. [Forest Service, Reno, NV (United States). Rocky Mountain Research Station

1998-11-01

This report focuses on the following two research projects relating to the biological effects of climate change: Hybridization and genetic diversity populations of Utah (Juniperus osteosperma) and western (Juniperus occidentalis) juniper: Evidence from nuclear ribosomal and chloroplast DNA; and Ecophysiological patterns of pinyon and juniper.

Socialist and postsocialist land-use legacies determine farm woodland composition and structure

DEFF Research Database (Denmark)

Plieninger, Tobias; Schaich, H.

2014-01-01

and structure of presocialist woodlands. We argue that forest conservation planning should actively consider land-use legacies, which are of particular relevance in the landscapes of Central and Eastern Europe, as these have undergone multiple, abrupt, and severe land-use transitions....... explicit assessment of differences in species richness, diversity, and evenness as well as forest physiognomy and structure among Eastern German farm woodlands established during (1) the presocialist era (until 1945), (2) the socialist era (1945-1990), and (3) the postsocialist era (after 1990). Aerial...... imagery was used to allocate woodlands to one of the three eras, after which a forest inventory of 120 woodlands was performed. The results show substantial differences in forest composition and structure. Presocialist-era woodlands are composed of native (mean 96 %), deciduous (mean 94 %) tree species...

Fire patterns in piñon and juniper land cover types in the Semiarid Western United States from 1984 through 2013

Science.gov (United States)

David I. Board; Jeanne C. Chambers; Richard F. Miller; Peter J. Weisberg

2018-01-01

Increases in area burned and fire size have been reported across a wide range of forest and shrubland types in the Western United States in recent decades, but little is known about potential changes in fire regimes of piñon and juniper land cover types. We evaluated spatio-temporal patterns of fire in piñon and juniper land cover types from the National Gap Analysis...

The heterogeneity of wooded-agricultural landscape mosaics influences woodland bird community assemblages

OpenAIRE

Neumann, Jessica L.; Griffiths, Geoffrey H.; Foster, Christopher W.; Holloway, Graham J.

2016-01-01

Context\\ud Landscape heterogeneity (the composition and configuration of different landcover types) plays a key role in shaping woodland bird assemblages in wooded-agricultural mosaics. Understanding how species respond to landscape factors could contribute to preventing further decline of woodland bird populations.\\ud Objective\\ud To investigate how woodland birds with different species traits respond to landscape heterogeneity, and to identify whether specific landcover types are important ...

Analisis Elemen Visual Pada Promosi Busana Muslimah di Instagram (Studi Kasus Merek Hijab Juniper Lane, Zaha, dan Zysku Xena di Bandung

Directory of Open Access Journals (Sweden)

Ramadita Fetrianggi

2017-06-01

Full Text Available Analysis of Visual Elements on Muslimah Clothing Promotion in Instagram (Case Study on Brands of Hijab Juniper Lane, Zaha, and Zysku Xena in Bandung. Muslim clothing in the form of hijab has become popular as a religious lifestyle and identity. The popularity of hijab is due to the promotion of marketing through instagram displaying muslim fashion clothing that is designed very interesting, so that consumers become interested and marketing becomes increasing. This study aims to examine muslim clothing photos on instagram hijab with brands of Juniper Lane, Zaha, and Zysku Xena in Bandung seen from the visual elements of photography. The research method used case study with descriptive approach through visual analysis. The research subjects are instagram photos on Juniper Lane hijab brand, Zaha, and Zysku Xena in Bandung. Data collection techniques were collected by observation, instagram photo documentation study, and interviews with local brand owners of hijab and consumers. Data were analyzed by visual analysis, content analysis, and qualitative analysis. The results show that muslim clothing photos on instagram with brands of hijab Juniper Lane, Zaha, and Zysku Xena in Bandung have fulfilled the visual elements of photography, so the photo design becomes attractive, the consumers become interested in them, and the marketing becomes increasing.

Energetic implications of disturbance caused by petroleum exploration to woodland caribou

International Nuclear Information System (INIS)

Bradshaw, C.J.A.; Boutin, S.

1998-01-01

A study was conducted to determine if there is a link between the decline in woodland caribou populations and petroleum exploration activity in the province of Alberta. To do this, a simple model was developed to estimate the energy costs of multiple encounters with disturbances (such as noise). The goal was to determine if woodland caribou in northeastern Alberta have been exposed to enough disturbances between 1988 and 1993 to cause winter mass loss to exceed either 15 per cent autumn mass or 20 per cent autumn mass. It was concluded that disturbance can have major energetic consequences for woodland caribou. Simulations have shown that petroleum exploration has biological consequences on woodland caribou, but it is difficult to infer long-term population effects from petroleum exploration. 50 refs., 2 tabs., 1 fig

Longleaf pine forests and woodlands: old growth under fire!

Science.gov (United States)

Joan L. Walker

1999-01-01

The author discusses a once widespread forest type of the Southeast – longleaf pine dominated forests and woodlands. This system depends on fire – more or less frequent, and often of low intensity. Because human-mediated landscape fragmentation has drastically changed the behavior of fire on longleaf pine dominated landscapes, these forests and woodlands will never be...

Coarse woody debris metrics in a California oak woodland

Science.gov (United States)

William D. Tietje; Michael A. Hardy; Christopher C. Yim

2015-01-01

Little information is available on the metrics of coarse woody debris (CWD) in California oak woodland, most notably at the scale of the stand and woodland type. In a remote part of the National Guard Post, Camp Roberts, that has not burned in over a half century, we tallied 314 pieces of CWD in a blue oak (Quercus douglasii)-coast live oak (

Effects of feeding ground redberry juniper (Juniperus pinchotii) to gestating ewes on pre- and postpartum performance, serum metabolites and hormones, milk fatty acid composition, and progeny preweaning performance.

Science.gov (United States)

Stewart, W C; Whitney, T R; Scholljegerdes, E J; Hallford, D M; Walker, J W; Adams, R P; Naumann, H D

2017-09-01

The objective of this research was to evaluate effects of replacing sorghum × Sudangrass hay with ground juniper in gestating ewe supplements on pre- and postpartum growth performance, serum metabolites and hormonal concentrations, milk fatty acid composition, and progeny preweaning performance. In a completely randomized design, commercial Rambouillet ewes (age = 3 to 5 yr; initial BW = 65.2 ± 1.6 kg) on a base diet of long-stem sorghum × Sudangrass hay were assigned to 1 of 4 dietary supplements in which ground juniper replaced 0% (CNTL), 33% (18JUN), 66% (36JUN), or 100% (54JUN) of the ground sorghum × Sudangrass hay in a pelleted supplement with ground juniper from d 38 ± 4 of gestation to 2 d postpartum. Treatment DM diet intake overall (g/kg BW) in ewes receiving no juniper was similar ( ≥ 0.38) to that of those receiving increasing concentrations of juniper. Changes in ewe BW and BCS were similar ( ≥ 0.24) in ewes throughout gestation. All serum metabolites and hormones were within normal clinical ranges; however, serum IGF-1 decreased linearly ( = 0.003), alanine increased (linear; = 0.003), and serum Na decreased (linear; = 0.049) as the percentage of juniper increased in the diet. Ewe milk fatty acid composition was similar ( > 0.05) for the majority of fatty acids across treatment groups, with the exception of arachidonic acid (C20:4n6) being greater ( hormones measured pre- and postpartum. Lamb birth weight and preweaning performance appeared unaffected by maternal consumption of ground juniper containing supplements. Results also provide novel information regarding the effects of plant secondary compound consumption throughout pregnancy on ewe and progeny performance and health.

Climate change effects on vegetation in the Pacific Northwest: a review and synthesis of the scientific literature and simulation model projections

Science.gov (United States)

David W. Peterson; Becky K. Kerns; Erich Kyle Dodson

2014-01-01

The purpose of this study was to review scientifi c knowledge and model projections on vegetation vulnerability to climatic and other environmental changes in the Pacifi c Northwest, with emphasis on fi ve major biome types: subalpine forests and alpine meadows, maritime coniferous forests, dry coniferous forests, savannas and woodlands (oak and juniper), and interior...

A demonstration project to test ecological restoration of a pinyon-juniper ecosystem

Science.gov (United States)

David W. Huffman; Michael T. Stoddard; Peter Z. Fule; W. Wallace Covington; H. B. Smith

2008-01-01

To test an approach for restoring historical stand densities and increasing plant species diversity of a pinyon-juniper ecosystem, we implemented a demonstration project at two sites (CR and GP) on the Grand Canyon-Parashant National Monument in northern Arizona. Historical records indicated that livestock grazing was intensive on the sites beginning in the late 1800s...

Facilitation of Quercus ilex recruitment by shrubs in Mediterranean open woodlands

NARCIS (Netherlands)

Smit, Christian; den Ouden, Jan; Diaz, Mario

Question: Insufficient tree regeneration threatens the long-term persistence of biodiverse Mediterranean open oak woodlands. Could shrubs, scarce due to decades of management ( clearing and ploughing), facilitate holm oak recruitment at both acorn and seedling stages? Location: Open oak woodlands in

Facilitation of Quercus ilex recruitment by shrubs in Mediterranean open woodlands

NARCIS (Netherlands)

Smit, C.; Ouden, den J.; Diaz, M.

2008-01-01

Question: Insufficient tree regeneration threatens the long-term persistence of biodiverse Mediterranean open oak woodlands. Could shrubs, scarce due to decades of management (clearing and ploughing), facilitate holm oak recruitment at both acorn and seedling stages? Location: Open oak woodlands in

The hidden treasures of long-term paired watershed monitoring in the forests and grasslands of Arizona, USA

Science.gov (United States)

B. Poff; D. G. Neary; V. Henderson; A. Tecle

2012-01-01

Beginning in the 1950s, researchers of the United States Department of Agriculture Forest Service established a series of paired watershed studies throughout north-central and eastern Arizona. A total of nine experimental watershed areas were established in the pinyon-juniper and chaparral woodlands, as well as the ponderosa pine and mixed conifer forests. While most...

Impacts of long-term precipitation manipulation on hydraulic architecture and xylem anatomy of piñon and juniper in Southwest USA.

Science.gov (United States)

Hudson, P J; Limousin, J M; Krofcheck, D J; Boutz, A L; Pangle, R E; Gehres, N; McDowell, N G; Pockman, W T

2018-02-01

Hydraulic architecture imposes a fundamental control on water transport, underpinning plant productivity, and survival. The extent to which hydraulic architecture of mature trees acclimates to chronic drought is poorly understood, limiting accuracy in predictions of forest responses to future droughts. We measured seasonal shoot hydraulic performance for multiple years to assess xylem acclimation in mature piñon (Pinus edulis) and juniper (Juniperus monosperma) after 3+ years of precipitation manipulation. Our treatments consisted of water addition (+20% ambient precipitation), partial precipitation-exclusion (-45% ambient precipitation), and exclusion-structure control. Supplemental watering elevated leaf water potential, sapwood-area specific hydraulic conductivity, and leaf-area specific hydraulic conductivity relative to precipitation exclusion. Shifts in allocation of leaf area to sapwood area enhanced differences between irrigated and droughted K L in piñon but not juniper. Piñon and juniper achieved similar K L under ambient conditions, but juniper matched or outperformed piñon in all physiological measurements under both increased and decreased precipitation treatments. Embolism vulnerability and xylem anatomy were unaffected by treatments in either species. Absence of significant acclimation combined with inferior performance for both hydraulic transport and safety suggests piñon has greater risk of local extirpation if aridity increases as predicted in the southwestern USA. © 2017 John Wiley & Sons Ltd.

Pinon-juniper reduction increases soil water availability of the resource growth pool

Science.gov (United States)

Bruce A. Roundy; Kert Young; Nathan Cline; April Hulet; Richard F. Miller; Robin J. Tausch; Jeanne C. Chambers; Ben Rau

2014-01-01

Managers reduce piñon (Pinus spp.) and juniper (Juniperus spp.) trees that are encroaching on sagebrush (Artemisia spp.) communities to lower fuel loads and increase cover of desirable understory species. All plant species in these communities depend on soil water held at > −1.5 MPa matric potential in the upper 0.3 m of soil for nutrient...

Likeliness to pay for oak woodlands by the residents of San Luis Obispo county

Science.gov (United States)

Sarah P. Cross

2002-01-01

The golden hillsides with scattered oaks, known throughout California, are decreasing each day. Some oak woodlands are being developed into residential and commercial communities while other woodlands are being converted into intensive agriculture, such as wine grape production. This continued decrease in oak woodlands has led some lawmakers to create preservation...

Oak woodland conservation management planning in southern CA - lessons learned

Science.gov (United States)

Rosi Dagit

2015-01-01

The California Oak Woodlands Conservation Act (AB 242 2001) established requirements for the preservation and protection of oak woodlands and trees, and allocated funding managed by the Wildlife Conservation Board. In order to qualify to use these funds, counties and cities need to adopt an oak conservation management plan. Between 2008 and 2011, a team of concerned...

Ancient woodland boundaries in Europe

Czech Academy of Sciences Publication Activity Database

Szabó, Péter

2010-01-01

Roč. 36, č. 2 (2010), s. 205-214 ISSN 0305-7488 R&D Projects: GA AV ČR IAA600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : ancient woodland * historical ecology * landscape archaeology Subject RIV: EF - Botanics Impact factor: 0.983, year: 2010

Understory cover responses to pinon-juniper treatments across tree dominance gradients in the Great Basin

Science.gov (United States)

Piñon (Pinus spp.) and juniper (Juniperus spp.) trees are reduced to restore native vegetation and avoid high severity fires where they have invaded sagebrush (Artemisia tridentata Nutt.) communities. To recommend treatment implementation which avoids threshold-crossing to invasive plant dominance w...

Oak woodlands as wildlife habitat

Science.gov (United States)

W. Tietje; K. Purcell; S. Drill

2005-01-01

This chapter provides local planners and policymakers with information on the diversity and abundance of oak woodland wildlife, wildlife habitat needs, and how local planning activities can influence wildlife abundance and diversity. Federal and state laws, particularly the federal and California Endangered Species Act and the California Environmental Quality Act (CEQA...

Soil phytoliths from miombo woodlands in Mozambique

Science.gov (United States)

Mercader, Julio; Bennett, Tim; Esselmont, Chris; Simpson, Steven; Walde, Dale

2011-01-01

This paper describes topsoil phytolith assemblages from 25 loci underneath miombo woodlands on an eco-transect intersecting the Mozambican Rift along a geographical, altitudinal, climatic and botanical gradient. We provide the first comprehensive overview of the phytolith spectrum that defines northern Mozambique's Zambezian floristic zone. Our classifying criteria derive from comparison with previously described and quantified reference collections of trees and grasses growing in the study area. We characterize the sedimentological and soil features of the matrices where phytoliths are found, establishing correlation among geo-edaphic variables and phytoliths. Descriptive statistics along with nonparametric and parametric statistical analyses evaluate phytolith grouping criteria, variation, robustness, and membership. From a taphonomic perspective, we attest that topsoil phytolith assemblages are polygenic and do not represent an episodic snapshot of extant vegetation, but a palimpsest from plants representing various disturbance episodes, succession stages, and ecological trends. Phytoliths retrieved from Mozambican miombo soils do not seem to trace altitudinal, temperature, or precipitation gradients, and no significant differences exist between highland and lowland phytolith assemblages. This article provides a phytolith analog for woodland environments that can guide future paleoenvironmental research. It also confirms that phytolith analysis is able to detect shifts in the woodland/grassland interface.

Acute aquatic toxicity of western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood oils.

Science.gov (United States)

Duringer, Jennifer M; Swan, Laurence R; Walker, Douglas B; Craig, A Morrie

2010-11-01

Recently, interest has developed for using essential oils from Western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood in commercial products such as pest repellents and cosmetics. In order to gauge the relative toxicological risk that these oils pose to freshwater and marine organisms, the acute aquatic toxicity of these oils was evaluated using OPPTS guidelines to the cladoceran Daphnia magna, the rainbow trout Oncorhynchus mykiss and the green alga Selenastrum capricornutum. For western juniper foliage oil, no toxicity was exhibited toward D. magna or O. mykiss, even at 5.0 mg/L (the highest concentration tested and limit of solubility). For toxicity to S. capricornutum using algal cell density, the 72 and 96 h EC50 value was 1.7 mg/L and the no observable effect concentration (NOEC) was 0.63 mg/L. For Port Orford cedar heartwood oil, no toxicity was exhibited toward O. mykiss or S. capricornutum, even at 5.0 mg/L (the highest concentration tested and limit of solubility). The 48-h D. magna EC50 value was 1.9 mg/L; the NOEC values for algal cell density were 1.25 mg/L (72 h) and 0.63 mg/L (96 h). In summary, this study shows that western juniper foliage and Port Orford cedar heartwood oils demonstrate little to no risk to aquatic organisms.

Small mammals in successional prairie woodlands of the northern Great Plains

Science.gov (United States)

Mark A. Rumble; John E. Gobeille

2001-01-01

Prairie woodlands comprise about 1 percent of the landscape in the northern Great Plains. However, prairie woodlands provide habitat for far more than 1 percent of the wildlife species that occur in the prairie region. With increasing pressures on natural resources, managers need methods for managing wildlife habitat and biodiversity that are based on ecological...

Woodland restoration in Scotland: ecology, history, culture, economics, politics and change.

Science.gov (United States)

Hobbs, Richard

2009-07-01

In the latter half of the 20th century, native pine woodlands in Scotland were restricted to small remnant areas within which there was little regeneration. These woodlands are important from a conservation perspective and are habitat for numerous species of conservation concern. Recent developments have seen a large increase in interest in woodland restoration and a dramatic increase in regeneration and woodland spread. The proximate factor enabling this regeneration is a reduction in grazing pressure from sheep and, particularly, deer. However, this has only been possible as a result of a complex interplay between ecological, political and socio-economic factors. We are currently seeing the decline of land management practices instituted 150-200 years ago, changes in land ownership patterns, cultural revival, and changes in societal perceptions of the Scottish landscape. These all feed into the current move to return large areas of the Scottish Highlands to tree cover. I emphasize the need to consider restoration in a multidisciplinary framework which accounts not just for the ecology involved but also the historical and cultural context.

Evaluation of the seasonal and annual abortifacient risk of western juniper trees on Oregon rangelands

Science.gov (United States)

Needles from ponderosa pine (Pinus ponderosa) trees are known to cause late term abortions in cattle. Recently, there have been several reports of abortion rates of 10-15% within cattle herds in Oregon after cattle were pastured in areas with abundant western juniper trees (Juniperus occidentalis)....

75 FR 44853 - Woodlands Bank, Bluffton, SC; Notice of Appointment of Receiver

Science.gov (United States)

2010-07-29

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision Woodlands Bank, Bluffton, SC; Notice of... the Home Owners' Loan Act, the Office of Thrift Supervision has duly appointed the Federal Deposit Insurance Corporation as sole Receiver for Woodlands Bank, Bluffton, South Carolina (OTS No. 08464), as of...

Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy

Science.gov (United States)

Liang, Eryuan; Lu, Xiaoming; Ren, Ping; Li, Xiaoxia; Zhu, Liping; Eckstein, Dieter

2012-01-01

Background and Aims Dendroclimatology is playing an important role in understanding past climatic changes on the Tibetan Plateau. Forests, however, are mainly confined to the eastern Tibetan Plateau. On the central Tibetan Plateau, in contrast, shrubs and dwarf shrubs need to be studied instead of trees as a source of climate information. The objectives of this study were to check the dendrochronological potential of the dwarf shrub Wilson juniper (Juniperus pingii var. wilsonii) growing from 4740 to 4780 m a.s.l. and to identify the climatic factors controlling its radial growth. Methods Forty-three discs from 33 stems of Wilson juniper were sampled near the north-eastern shore of the Nam Co (Heavenly Lake). Cross-dating was performed along two directions of each stem, avoiding the compression-wood side as far as possible. A ring-width chronology was developed after a negative exponential function or a straight line of any slope had been fit to the raw measurements. Then, correlations were calculated between the standard ring-width chronology and monthly climate data recorded by a weather station around 100 km away. Key Results Our study has shown high dendrochronological potential of Wilson juniper, based on its longevity (one individual was 324 years old), well-defined growth rings, reliable cross-dating between individuals and distinct climatic signals reflected by the ring-width variability. Unlike dwarf shrubs in the circum-arctic tundra ecosystem which positively responded to above-average temperature in the growing season, moisture turned out to be growth limiting for Wilson juniper, particularly the loss of moisture caused by high maximum temperatures in May–June. Conclusions Because of the wide distribution of shrub and dwarf shrub species on the central Tibetan Plateau, an exciting prospect was opened up to extend the presently existing tree-ring networks far up into one of the largest tundra regions of the world. PMID:22210848

Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy.

Science.gov (United States)

Liang, Eryuan; Lu, Xiaoming; Ren, Ping; Li, Xiaoxia; Zhu, Liping; Eckstein, Dieter

2012-03-01

Dendroclimatology is playing an important role in understanding past climatic changes on the Tibetan Plateau. Forests, however, are mainly confined to the eastern Tibetan Plateau. On the central Tibetan Plateau, in contrast, shrubs and dwarf shrubs need to be studied instead of trees as a source of climate information. The objectives of this study were to check the dendrochronological potential of the dwarf shrub Wilson juniper (Juniperus pingii var. wilsonii) growing from 4740 to 4780 m a.s.l. and to identify the climatic factors controlling its radial growth. Forty-three discs from 33 stems of Wilson juniper were sampled near the north-eastern shore of the Nam Co (Heavenly Lake). Cross-dating was performed along two directions of each stem, avoiding the compression-wood side as far as possible. A ring-width chronology was developed after a negative exponential function or a straight line of any slope had been fit to the raw measurements. Then, correlations were calculated between the standard ring-width chronology and monthly climate data recorded by a weather station around 100 km away. Our study has shown high dendrochronological potential of Wilson juniper, based on its longevity (one individual was 324 years old), well-defined growth rings, reliable cross-dating between individuals and distinct climatic signals reflected by the ring-width variability. Unlike dwarf shrubs in the circum-arctic tundra ecosystem which positively responded to above-average temperature in the growing season, moisture turned out to be growth limiting for Wilson juniper, particularly the loss of moisture caused by high maximum temperatures in May-June. Because of the wide distribution of shrub and dwarf shrub species on the central Tibetan Plateau, an exciting prospect was opened up to extend the presently existing tree-ring networks far up into one of the largest tundra regions of the world.

Nature's Notebook Provides Phenology Observations for NASA Juniper Phenology and Pollen Transport Project

Science.gov (United States)

Luval, J. C.; Crimmins, T. M.; Sprigg, W. A.; Levetin, E.; Huete, A.; Nickovic, S.; Prasad, A.; Vukovic, A.; VandeWater, P. K.; Budge, A. M.;

Shasta ground sloth ( Nothrotheriops shastense hoffstetter) at Shelter Cave, New Mexico: Environment, diet, and extinction

Science.gov (United States)

Thompson, Robert S.; Van Devender, Thomas R.; Martin, Paul S.; Foppe, Theresa; Long, Austin

1980-11-01

Seven coprolites of the extinct Shasta ground sloth ( Nothrotheriops shastense) were recently discovered in the Los Angeles County Museum collection from Shelter Cave, New Mexico. Three dung balls provided radiocarbon ages of 11,330, 12,330 and 12,430 yr B.P. Packrat ( Neotoma) middens disclose a xeric juniper woodland at Shelter Cave during the sloth's occupation. Plant cuticles from the dung indicate that the ground sloth had a diet dominated by mormon tea ( Ephedra) and other xerophytic shrubs. Pollen spectra from the coprolites have high representations of anemophilous plants and low representations of the dietary items shown in the cuticle analysis. Fifteen radiocarbon dates of sloth dung obtained since 1974 strengthen the hypothesis that sloth extinction occurred about 11,000 yr B.P. Paleoenvironmental studies indicate that ground sloths lived in juniper woodlands and montane conifer communities. Nothrotheriops commonly dined on shrubs that are still present in these habitats. It is difficult to explain the demise of the Shasta ground sloth by climatic change or dietary stress. Human predation remains as a possible explanation; ground sloth extinction appears to coincide with the time of Clovis mammoth hunters.

Grassland to woodland transitions: Dynamic response of microbial community structure and carbon use patterns

Science.gov (United States)

Creamer, Courtney A.; Filley, Timothy R.; Boutton, Thomas W.; Rowe, Helen I.

2016-06-01

Woodland encroachment into grasslands is a globally pervasive phenomenon attributed to land use change, fire suppression, and climate change. This vegetation shift impacts ecosystem services such as ground water allocation, carbon (C) and nutrient status of soils, aboveground and belowground biodiversity, and soil structure. We hypothesized that woodland encroachment would alter microbial community structure and function and would be related to patterns in soil C accumulation. To address this hypothesis, we measured the composition and δ13C values of soil microbial phospholipids (PLFAs) along successional chronosequences from C4-dominated grasslands to C3-dominated woodlands (small discrete clusters and larger groves) spanning up to 134 years. Woodland development increased microbial biomass, soil C and nitrogen (N) concentrations, and altered microbial community composition. The relative abundance of gram-negative bacteria (cy19:0) increased linearly with stand age, consistent with decreases in soil pH and/or greater rhizosphere development and corresponding increases in C inputs. δ13C values of all PLFAs decreased with time following woody encroachment, indicating assimilation of woodland C sources. Among the microbial groups, fungi and actinobacteria in woodland soils selectively assimilated grassland C to a greater extent than its contribution to bulk soil. Between the two woodland types, microbes in the groves incorporated relatively more of the relict C4-C than those in the clusters, potentially due to differences in below ground plant C allocation and organo-mineral association. Changes in plant productivity and C accessibility (rather than C chemistry) dictated microbial C utilization in this system in response to shrub encroachment.

Reconsidering the process for bow-stave removal from juniper trees in the Great Basin

Science.gov (United States)

Constance I. Millar; Kevin T. Smith

2017-01-01

We question the growth arrestment hypothesis for bow stave removal used by indigenous people in the western Great Basin. Using modern understanding of tree growth and wound response, we suggest that growth would not be arrested by one or two transverse notches along a juniper stem. Rather these would trigger compartmentalization, which limits cambial death to within 10...

Alien plant invasions in European woodlands

NARCIS (Netherlands)

Wagner, Viktoria; Chytrý, Milan; Jiménez-Alfaro, Borja; Pergl, Jan; Hennekens, Stephan; Biurrun, Idoia; Knollová, Ilona; Berg, Christian; Vassilev, Kiril; Rodwell, John S.; Škvorc, Željko; Jandt, Ute; Ewald, Jörg; Jansen, Florian; Tsiripidis, Ioannis; Botta-Dukát, Zoltán; Casella, Laura; Attorre, Fabio; Rašomavičius, Valerijus; Ćušterevska, Renata; Schaminée, Joop H.J.; Brunet, Jörg; Lenoir, Jonathan; Svenning, Jens Christian; Kącki, Zygmunt; Petrášová-Šibíková, Mária; Šilc, Urban; García-Mijangos, Itziar; Campos, Juan Antonio; Fernández-González, Federico; Wohlgemuth, Thomas; Onyshchenko, Viktor; Pyšek, Petr

2017-01-01

Aim: Woodlands make up a third of European territory and carry out important ecosystem functions, yet a comprehensive overview of their invasion by alien plants has never been undertaken across this continent. Location: Europe. Methods: We extracted data from 251,740 vegetation plots stored in the

Radionuclide behaviour in a coniferous woodland ecosystem in Cumbria, UK

International Nuclear Information System (INIS)

Jones, S.R.; Copplestone, D.; Johnson, M.S.

1996-01-01

The behaviour of 134Cs, 137Cs, 238Pu, 239+240Pu and 241Am, in food chains in a semi-natural woodland has been investigated and doses to the ecosystem due to the presence of these radionuclides of anthropogenic origin have been assessed. The woodland is located within 1 km of the coastal British Nuclear Fuels plc (BNFL) reprocessing plant at Sellafield, Cumbria (O.S. Grid Reference: NY 037045) and has received an input of radionuclides primarily through atmospheric discharges from the Sellafield site throughout its operational history of more than 40 years. Deposition has been enhanced by interception by the canopy, such that deposits in the woodland are significantly higher than adjacent pasture land. Within the wood, deposition is greatest along the front (or leading) edge in relation to aerosols transported to the woodland from Sellafield, due to the 'edge effect'. Despite the high radionuclide deposits, relatively low uptake and mobility within the ecosystem was observed. Estimated doses to the ecosystem at around 2 mGy a -1 , were dominated by external irradiation and were well below the levels thought to be necessary to harm terrestrial ecosystems. A provisional conclusion at this stage is that the measures taken to control emissions from Sellafield in line with radiological protection standards for humans have also been adequate to protect this potentially vulnerable ecosystem

The development of an approach to assess critical loads of acidity for woodland habitats in Great Britain

Directory of Open Access Journals (Sweden)

S. J. Langan

2004-01-01

Full Text Available Alongside other countries that are signatories to the UNECE Convention Long Range Transboundary on Air Pollution, the UK is committed to reducing the impact of air pollution on the environment. To advise and guide this policy in relation to atmospheric emissions of sulphur and nitrogen, a critical load approach has been developed. To assess the potential impact of these pollutants on woodland habitats a steady state, simple mass balance model has been parameterised. For mineral soils, a Ca:Al ratio in soil solution has been used as the critical load indicator for potential damage. For peat and organic soils critical loads have been set according to a pH criterion. Together these approaches have been used with national datasets to examine the potential scale of acidification in woodland habitats across the UK. The results can be mapped to show the spatial variability in critical loads of the three principal woodland habitat types (managed coniferous, managed broadleaved/ mixed woodland and unmanaged woodland. The results suggest that there is a wide range of critical loads. The most sensitive (lowest critical loads are associated with managed coniferous followed by unmanaged woodland on peat soils. Calculations indicate that at steady state, acid deposition inputs reported for 1995–1997 result in a large proportion of all the woodland habitats identified receiving deposition loads in excess of their critical load; i.e. critical loads are exceeded. These are discussed in relation to future modelled depositions for 2010. Whilst significant widespread negative impacts of such deposition on UK woodland habitats have not been reported, the work serves to illustrate that if acid deposition inputs were maintained and projected emissions reductions not achieved, the long-term sustainability of large areas of woodland in the UK could be compromised. Keywords: critical loads, acid deposition, acidification, woodland, simple mass balance model

Woodland in Practical Skills Therapeutic Education

Science.gov (United States)

Mata, Paula; Gibons, Kenneth; Mata, Fernando

2016-01-01

Modern urban life provides less opportunities to contact with nature, which is a potential cause of developmental deviances in children. We investigated the potential therapeutic effect of woodlands, within the context of Practical Skills Therapeutic Education at the Ruskin Mill College, UK. Data on physical and emotional perceptions were…

Woodland expansion in South African grassy biomes based on satellite observations (1990-2013): general patterns and potential drivers.

Science.gov (United States)

Skowno, Andrew L; Thompson, Mark W; Hiestermann, Jens; Ripley, Brad; West, Adam G; Bond, William J

2017-06-01

Increases in woody plant cover in savanna grassland environments have been reported on globally for over 50 years and are generally perceived as a threat to rangeland productivity and biodiversity. Despite this, few attempts have been made to estimate the extent of woodland increase at a national scale, principally due to technical constraints such as availability of appropriate remote sensing products. In this study, we aimed to measure the extent to which woodlands have replaced grasslands in South Africa's grassy biomes. We use multiseason Landsat data in conjunction with satellite L-band radar backscatter data to estimate the extent of woodlands and grasslands in 1990 and 2013. The method employed allows for a unique, nationwide measurement of transitions between grassland and woodland classes in recent decades. We estimate that during the 23-year study period, woodlands have replaced grasslands over ~57 000 km 2 and conversely that grasslands have replaced woodlands over ~30 000 km 2 , a net increase in the extent of woodland of ~27 000 km 2 and an annual increase of 0.22%. The changes varied markedly across the country; areas receiving over 500 mm mean annual precipitation showed higher rates of woodland expansion than regions receiving 0.19% yr -1 ). The woodland change map presented here provides a unique opportunity to test the numerous models of woody plant encroachment at a national/regional scale. © 2016 John Wiley & Sons Ltd.

Effect of firewood harvesting on birds in a California oak-pine woodland

Science.gov (United States)

Paul A. Aigner; William M. Block; Michael L. Morrison

1998-01-01

Despite a history of oak clearing and thinning in California, little is known about the effects of firewood harvesting on wildlife in oak woodlands. We studied the effect of firewood harvesting on population trends of birds during the breeding season in an oak-pine woodland in the foothills of the northern Sierra Nevada, California. During fall-winter of 1993-94, total...

Thermoregulatory capabilities of the woodland dormouse ...

African Journals Online (AJOL)

We measured metabolism and thermoregulation in woodland dormice acclimated to long-day length, moderate temperature and abundant food over a temperature range (Ta) of approximately 5–37°C. The thermal neutral zone for this species lay between 29 and 35°C. Estimated resting metabolic rate (RMR) within this ...

Effects of short-rotation controlled burning on amphibians and reptiles in pine woodlands

Science.gov (United States)

Roger W. Perry; D. Craig Rudolph; Ronald E. Thill

2012-01-01

Fire is being used increasingly as a forest management tool throughout North America, but its effects on reptiles and amphibians in many ecosystems are unclear. Open woodlands with understories dominated by herbaceous vegetation benefit many wildlife species, but maintaining these woodlands requires frequent burning. Although many studies have compared herpetofaunal...

Nest-site selection and nest survival of Lewis's woodpecker in aspen riparian woodlands

Science.gov (United States)

Karen R. Newlon; Victoria A. Saab

2011-01-01

Riparian woodlands of aspen (Populus tremuloides) provide valuable breeding habitat for several cavity-nesting birds. Although anecdotal information for this habitat is available for Lewis's Woodpecker (Melanerpes lewis), no study has previously examined the importance of aspen woodlands to this species' breeding biology. From 2002 to 2004, we monitored 76...

Canopy Density Mapping on Ultracam-D Aerial Imagery in Zagros Woodlands, Iran

Science.gov (United States)

Erfanifard, Y.; Khodaee, Z.

2013-09-01

Canopy density maps express different characteristics of forest stands, especially in woodlands. Obtaining such maps by field measurements is so expensive and time-consuming. It seems necessary to find suitable techniques to produce these maps to be used in sustainable management of woodland ecosystems. In this research, a robust procedure was suggested to obtain these maps by very high spatial resolution aerial imagery. It was aimed to produce canopy density maps by UltraCam-D aerial imagery, newly taken in Zagros woodlands by Iran National Geographic Organization (NGO), in this study. A 30 ha plot of Persian oak (Quercus persica) coppice trees was selected in Zagros woodlands, Iran. The very high spatial resolution aerial imagery of the plot purchased from NGO, was classified by kNN technique and the tree crowns were extracted precisely. The canopy density was determined in each cell of different meshes with different sizes overlaid on the study area map. The accuracy of the final maps was investigated by the ground truth obtained by complete field measurements. The results showed that the proposed method of obtaining canopy density maps was efficient enough in the study area. The final canopy density map obtained by a mesh with 30 Ar (3000 m2) cell size had 80% overall accuracy and 0.61 KHAT coefficient of agreement which shows a great agreement with the observed samples. This method can also be tested in other case studies to reveal its capability in canopy density map production in woodlands.

Perceived personal safety in relation to urban woodland vegetation – A review

OpenAIRE

Jansson, Märit; Fors, Hanna; Lindgren, Therese; Wiström, Björn

2013-01-01

Urban woodland vegetation provides people with many aesthetic, ecological and psychological benefits, but can also generate problems concerning people’s perception of safety. This paper reviews existing knowledge about perceived personal safety in relation to vegetation, particularly woodland vegetation, in urban green spaces such as parks and residential areas. Individual and social factors, but also vegetation character, maintenance and design, proved to be important for perceived personal ...

Arborealities: The Tactile Ecology of Hardy’s Woodlanders

Directory of Open Access Journals (Sweden)

William A. Cohen

2014-10-01

Full Text Available This article asks what consequences two recent movements in scholarship - affect theory and environmental studies - might have for understanding the Victorian tactile imagination. Thomas Hardy's 1887 novel 'The Woodlanders' provides a means of addressing this question, for it shares with posthumanist critics a view that people are material things in a world of things, and that the world is itself a collection of vital agencies and networked actors. Hardy shows how a tactile modality provides a point of entry into discussions of both affect and ecology, situating the human in a proximate, contiguous relation to both bodily and environmental materialities. 'The Woodlanders' offers a world in which trees, in particular, work on - and are in turn worked on by - human objects; a world in which, one might say, the trees are people and the people are trees. This arboreality is far from a sentimental oneness with nature, nor is it an exercise in anthropomorphization. Instead, it provides a recognition of the inhuman, material, and sensate aspects of the human; or, perhaps better, of the human as rooted, budding, leafy, and abloom. Like some recent theoretical accounts, 'The Woodlanders' disperses agency among human and non-human elements alike, employing a tactile mode of representation to break down distinctions between them. Normal 0 false false false EN-US X-NONE X-NONE

Successful de-fragmentation of woodland by planting in an agricultural landscape? An assessment based on landscape indicators.

Science.gov (United States)

Quine, C P; Watts, K

2009-01-01

Habitat fragmentation is the focus of much conservation concern and associated research. In some countries, such as Britain, the main phase of fragmentation occurred centuries ago and the focus of conservation management is now on restoration and recovery. Scenario studies have suggested that spatial targeting is preferable if landscape scale restoration is to be achieved, and that this should bring greater benefits than site-focussed activities but this has rarely been tested in practice. In Britain, woodland expansion has been encouraged through a number of financial incentives, which have evolved from instruments that encouraged almost any addition to the potential woodland resource, to grant schemes that have set out to restore connectivity to remnant ancient woodland. This study assessed the degree of de-fragmentation achieved by woodland expansion on the Isle of Wight and in particular the success of spatial targeting of new woodland planting implemented through grant aid in the JIGSAW (Joining and Increasing Grant Scheme for Ancient Woodland) scheme. Five steps in the re-development of broad-leaved woodland were tested using eight indicators - six commonly used landscape metrics, and two ecologically scaled indicators derived from application of least-cost network evaluation. Only half of the measures indicated de-fragmentation over the whole sequence of five steps. However, the spatial targeting did appear successful, when compared to equivalent untargeted grant-aided woodland expansion, and resulted in positive change to six of the eight indicators. We discuss the utility of the indicators and ways in which future targeting could be supported by their application.

Factors affecting soil fauna feeding activity in a fragmented lowland temperate deciduous woodland.

Science.gov (United States)

Simpson, Jake E; Slade, Eleanor; Riutta, Terhi; Taylor, Michele E

2012-01-01

British temperate broadleaf woodlands have been widely fragmented since the advent of modern agriculture and development. As a result, a higher proportion of woodland area is now subject to edge effects which can alter the efficiency of ecosystem functions. These areas are particularly sensitive to drought. Decomposition of detritus and nutrient cycling are driven by soil microbe and fauna coactivity. The bait lamina assay was used to assess soil fauna trophic activity in the upper soil horizons at five sites in Wytham Woods, Oxfordshire: two edge, two intermediate and one core site. Faunal trophic activity was highest in the core of the woodland, and lowest at the edge, which was correlated with a decreasing soil moisture gradient. The efficiency of the assay was tested using four different bait flavours: standardised, ash (Fraxinus excelsior L.), oak (Quercus robur L.), and sycamore (Acer pseudoplatanus L.). The standardised bait proved the most efficient flavour in terms of feeding activity. This study suggests that decomposition and nutrient cycling may be compromised in many of the UK's small, fragmented woodlands in the event of drought or climate change.

Determination of collected quantities of wild strawbery, bluberry and juniper in Serbia in relation to different scenarios of climate change

Directory of Open Access Journals (Sweden)

Ranković Nenad

2017-01-01

Full Text Available This study examines the influence of some climate elements on the collected quantities of blueberry, wild strawberry and juniper in Serbia. The main objective of the research is to predict the quantity of selected forest fruits depending on the different climate change scenarios (A1Bmin, A1Bmax, A2min and A2max. The general (modeling method, basic (dialectical and specific scientific methods (induction and deduction, analysis and synthesis, abstraction and concretization were used. Regression models were used in data processing, where the focus was on the statistical significance of the correlation coefficient in relation to the statistical significance of the parameters. The research found that, in the coming period, with the increase in temperature and precipitation, an increase in the collected amount of wild strawberries and blueberries could be expected, and the decline of juniper. Longer-term forecasts indicate expected growth with wild strawberries and blueberries with a tendency to slow down after 2040, and expected decline with juniper, with the same slow down tendency after 2040. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 43007Studies of climate changes and their impact on the environment - monitoring impacts, adaptation and mitigation, sub-project No. 43007/16-III: Socio-economic development, mitigation and adaptation to climate change

Unsustainable charcoal production as a contributing factor to woodland fragmentation in southeast Kenya

Directory of Open Access Journals (Sweden)

Ruuska, Eeva

2013-06-01

Full Text Available Drawing from a holistic research approach, this paper contributes to the studies of land cover change and sustainable development in Kenya, and to the planning of sustainable future in Dakatcha Woodland, SE Kenya. As an un-protected global hotspot for biodiversity, Dakatcha Woodland has suffered from unsustainable forest resource use. The relation of charcoal production to land cover change and its socio-economic impact are studied in detail. A supervised land cover classification formed using four SPOT satellite images from 2005/06 and 2011 revealed that the woodland is fragmenting and the Important Bird Area (IBA demarcation should be reconsidered. Through in-situ observation, household questionnaires and semi-structured expert interviews it was found that more than half of the 90 households assessed are involved in charcoal production which is higher figure than peer studies have suggested, and that the charcoal network offers income to many, but bears an negative impact on the environment. It was discovered that, like in Kenya, in Dakatcha Woodland, too, the demand for woodfuels (charcoal and fuelwood is one of the key drivers of deforestation and land degradation. As such, woodfuel energy is a cross cutting issue, tying together forest resources, livelihoods and sustainable development, and thus demands further research. Forest management of Dakatcha Woodland must be planned in accordance with all stakeholders in a sustainable manner, drawing from agroforestry and participatory forest management systems, and keeping environmental factors in mind for the maintenance of ecosystem services.

Development of secondary woodland in oak wood pastures reduces the richness of rare epiphytic lichens.

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Heidi Paltto

Full Text Available Wooded pastures with ancient trees were formerly abundant throughout Europe, but during the last century, grazing has largely been abandoned often resulting in dense forests. Ancient trees constitute habitat for many declining and threatened species, but the effects of secondary woodland on the biodiversity associated with these trees are largely unknown. We tested for difference in species richness, occurrence, and abundance of a set of nationally and regionally red-listed epiphytic lichens between ancient oaks located in secondary woodland and ancient oaks located in open conditions. We refined the test of the effect of secondary woodland by also including other explanatory variables. Species occurrence and abundance were modelled jointly using overdispersed zero-inflated Poisson models. The richness of the red-listed lichens on ancient oaks in secondary woodland was half of that compared with oaks growing in open conditions. The species-level analyses revealed that this was mainly the result of lower occupancy of two of the study species. The tree-level abundance of one species was also lower in secondary woodland. Potential explanations for this pattern are that the study lichens are adapted to desiccating conditions enhancing their population persistence by low competition or that open, windy conditions enhance their colonisation rate. This means that the development of secondary woodland is a threat to red-listed epiphytic lichens. We therefore suggest that woody vegetation is cleared and grazing resumed in abandoned oak pastures. Importantly, this will also benefit the vitality of the oaks.

Minimizing risk associated with shallow burial of waste in semiarid ecosystems: Erosion and vegetation dynamics

International Nuclear Information System (INIS)

Breshears, D.D.; Martens, S.N.; Nyhan, J.W.; Springer, E.P.; Wilcox, B.P.

1994-01-01

Numerous regulations govern the disposal of low-level radioactive and hazardous waste by burial in shallow pits. The overall goal of these regulations is to reduce the risk to humans and components of the ecosystem for 500 to 1 000 years. Erosional loss of the soil profile covering waste and contamination of groundwater by leachate are two pathways that influence human and ecological risks. Screening calculations for a waste site in a pinyon-juniper woodland at Los Alamos National Laboratory predict the entire 2 m cover of a waste site could be lost by erosion in less than 500 years. In contrast, less than 0.001% of the waste would reach groundwater by leachate. Predicted erosion rates depend highly on plant cover. The boundary between ponderosa pine forest and pinyon-juniper woodland has shifted more than 1 km in less than 50 years in the Los Alamos region and additional boundary shifts have been hypothesized in conjunction with global warming. High erosion rates (> 0.2 cm per year) have been measured in these transition zones. In concert, these results suggest that risk associated with erosional loss of the waste site cover may greatly exceed risks associated with groundwater contamination in semiarid ecosystems

Predicting Polylepis distribution: vulnerable and increasingly important Andean woodlands

Directory of Open Access Journals (Sweden)

Brian R. Zutta

2012-11-01

Full Text Available Polylepis woodlands are a vital resource for preserving biodiversity and hydrological functions, which will be altered by climate change and challenge the sustainability of local human communities. However, these highaltitude Andean ecosystems are becoming increasingly vulnerable due to anthropogenic pressure including fragmentation, deforestation and the increase in livestock. Predicting the distribution of native woodlands has become increasingly important to counteract the negative effects of climate change through reforestation and conservation. The objective of this study was to develop and analyze the distribution models of two species that form extensive woodlands along the Andes, namely Polylepis sericea and P. weberbaueri. This study utilized the program Maxent, climate and remotely sensed environmental layers at 1 km resolution. The predicted distribution model for P. sericea indicated that the species could be located in a variety of habitats along the Andean Cordillera, while P. weberbaueri was restricted to the high elevations of southern Peru and Bolivia. For both species, elevation and temperature metrics were the most significant factors for predicted distribution. Further model refinement of Polylepis and other Andean species using increasingly available satellite data demonstrate the potential to help define areas of diversity and improve conservation strategies for the Andes.

Classification and mapping of the composition and structure of dry woodland and savanna in the eastern Okavango Delta

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Michelle J. Tedder

2013-02-01

Full Text Available The dry woodland and savanna regions of the Okavango Delta form a transition zone between the Okavango Swamps and the Kalahari Desert and have been largely overlooked in terms of vegetation classification and mapping. This study focused on the species composition and height structure of this vegetation, with the aim of identifying vegetation classes and providing a vegetation map accompanied by quantitative data. Two hundred and fifty-six plots (50 m × 50 m were sampled and species cover abundance, total cover and structural composition were recorded. The plots were classified using agglomerative, hierarchical cluster analysis using group means and Bray-Curtis similarity and groups described using indicator species analysis. In total, 23 woody species and 28 grass species were recorded. Acacia erioloba and Colophospermum mopane were the most common woody species, whilst Urochloa mossambicensis, Panicum maximum, Dactyloctenium gigantiumand Eragrostis lehmanniana were the most widespread grasses. Eleven vegetation types were identified, with the most widespread being Short mixed mopane woodland, Tall mopane woodland and Tall mixed mopane woodland, covering 288.73 km2 (28%, 209.14 km2 (20% and 173.30 km2 (17% of the area, respectively. Despite their extensive area, these three vegetation types were the least species-rich, whilst Palm thornveld, Short mixed broadleaf woodland and Open mixed Acacia woodland were the most taxonomically variable. By contrast, Closed mixed Acacia woodland and Closed Acacia–Combretum woodland had the most limited distribution, accounting for less than 1% of the mapped area each.Conservation implications: The dry woodland and savanna vegetation of the Okavango Delta comprises a much wider suite of plant communities than the Acacia-dominated and Mopane-dominated classifications often used. This classification provided a more detailed understanding of this vegetation and essential background information for monitoring

Mapping decadal land cover changes in the woodlands of north eastern Namibia using the Landsat satellite archive (1975-2014)

Science.gov (United States)

Wingate, Vladimir; Phinn, Stuart; Kuhn, Nikolaus

2016-04-01

Woodland savannahs provide essential ecosystem functions and services to communities. On the African continent, they are widely utilized and converted to intensive land uses. This study investigates the land cover changes over 108,038 km2 in NE Namibia using multi-sensor Landsat imagery, at decadal intervals from 1975 to 2014, with a post-classification change detection method and supervised Regression Tree classifiers. We discuss likely impacts of land tenure and reforms over the past four decades on changes in land use and land cover. These included losses, gains and exchanges between predominant land cover classes. Exchanges comprised logical conversions between woodland and agricultural classes, implying woodland clearing for arable farming, cropland abandonment and vegetation succession. The dominant change was a reduction in the area of the woodland class due to the expansion of the agricultural class, specifically, small-scale cereal and pastoral production. Woodland area decreased from 90% of the study area in 1975 to 83% in 2014, while cleared land increased from 9% to 14%. We found that the main land cover changes are conversion from woodland to agricultural and urban land uses, driven by urban expansion and woodland clearing for subsistence-based agriculture and pastoralism.

75 FR 71463 - Woodland Mills Corporation Mill Spring, NC; Notice of Revised Determination on Reconsideration

Science.gov (United States)

2010-11-23

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-73,695] Woodland Mills Corporation Mill Spring, NC; Notice of Revised Determination on Reconsideration By application dated July 22... regarding the eligibility of workers and former workers of Woodland Mills Corporation, Mill Spring, North...

At the Crossroads: Does the Configuration of Roadside Vegetation Affect Woodland Bird Communities in Rural Landscapes?

Science.gov (United States)

Hall, Mark; Nimmo, Dale; Bennett, Andrew F.

2016-01-01

In agricultural regions worldwide, linear networks of vegetation such as hedges, fencerows and live fences provide habitat for plant and animal species in heavily modified landscapes. In Australia, networks of remnant native vegetation along roadsides are a distinctive feature of many rural landscapes. Here, we investigated the richness and composition of woodland-dependent bird communities in networks of eucalypt woodland vegetation along roadsides, in an agricultural region in which >80% of native woodland and forest vegetation has been cleared. We stratified sites in a) cross sections and b) linear strips of roadside vegetation, to test the influence on woodland birds of site location and configuration in the linear network (the ‘intersection effect’). We also examined the influence of tree size at the site, the amount of wooded vegetation surrounding the site, and the abundance of an aggressive native species, the noisy miner Manorina melanocephala. Birds were surveyed at 26 pairs of sites (cross section or linear strip) on four occasions. A total of 66 species was recorded, including 35 woodland species. The richness of woodland bird species was influenced by site configuration, with more species present at cross sections, particularly those with larger trees (>30 cm diameter). However, the strongest influence on species richness was the relative abundance of the noisy miner. The richness of woodland birds at sites where noisy miners were abundant was ~20% of that where miners were absent. These results recognise the value of networks of roadside vegetation as habitat for woodland birds in depleted agricultural landscapes; but highlight that this value is not realised for much of this vast vegetation network because of the dominance of the noisy miner. Nevertheless, roadside vegetation is particularly important where the configuration of networks create nodes that facilitate movement. Globally, the protection, conservation and restoration of such linear

At the Crossroads: Does the Configuration of Roadside Vegetation Affect Woodland Bird Communities in Rural Landscapes?

Science.gov (United States)

Hall, Mark; Nimmo, Dale; Bennett, Andrew F

2016-01-01

In agricultural regions worldwide, linear networks of vegetation such as hedges, fencerows and live fences provide habitat for plant and animal species in heavily modified landscapes. In Australia, networks of remnant native vegetation along roadsides are a distinctive feature of many rural landscapes. Here, we investigated the richness and composition of woodland-dependent bird communities in networks of eucalypt woodland vegetation along roadsides, in an agricultural region in which >80% of native woodland and forest vegetation has been cleared. We stratified sites in a) cross sections and b) linear strips of roadside vegetation, to test the influence on woodland birds of site location and configuration in the linear network (the 'intersection effect'). We also examined the influence of tree size at the site, the amount of wooded vegetation surrounding the site, and the abundance of an aggressive native species, the noisy miner Manorina melanocephala. Birds were surveyed at 26 pairs of sites (cross section or linear strip) on four occasions. A total of 66 species was recorded, including 35 woodland species. The richness of woodland bird species was influenced by site configuration, with more species present at cross sections, particularly those with larger trees (>30 cm diameter). However, the strongest influence on species richness was the relative abundance of the noisy miner. The richness of woodland birds at sites where noisy miners were abundant was ~20% of that where miners were absent. These results recognise the value of networks of roadside vegetation as habitat for woodland birds in depleted agricultural landscapes; but highlight that this value is not realised for much of this vast vegetation network because of the dominance of the noisy miner. Nevertheless, roadside vegetation is particularly important where the configuration of networks create nodes that facilitate movement. Globally, the protection, conservation and restoration of such linear

Factors affecting soil fauna feeding activity in a fragmented lowland temperate deciduous woodland.

Directory of Open Access Journals (Sweden)

Jake E Simpson

Full Text Available British temperate broadleaf woodlands have been widely fragmented since the advent of modern agriculture and development. As a result, a higher proportion of woodland area is now subject to edge effects which can alter the efficiency of ecosystem functions. These areas are particularly sensitive to drought. Decomposition of detritus and nutrient cycling are driven by soil microbe and fauna coactivity. The bait lamina assay was used to assess soil fauna trophic activity in the upper soil horizons at five sites in Wytham Woods, Oxfordshire: two edge, two intermediate and one core site. Faunal trophic activity was highest in the core of the woodland, and lowest at the edge, which was correlated with a decreasing soil moisture gradient. The efficiency of the assay was tested using four different bait flavours: standardised, ash (Fraxinus excelsior L., oak (Quercus robur L., and sycamore (Acer pseudoplatanus L.. The standardised bait proved the most efficient flavour in terms of feeding activity. This study suggests that decomposition and nutrient cycling may be compromised in many of the UK's small, fragmented woodlands in the event of drought or climate change.

USDA Forest Service National Woodland Owner Survey, 2011-2013: design, implementation, and estimation methods

Science.gov (United States)

Brett J. Butler; Brenton J. Dickinson; Jaketon H. Hewes; Sarah M. Butler; Kyle Andrejczyk; Marla. Markowski-Lindsay

2016-01-01

The National Woodland Owner Survey (NWOS) is conducted by the U.S. Forest Service, Forest Inventory and Analysis program to increase the understanding of the attitudes, behaviors, and demographics of private forest and woodland ownerships across the United States. The information is intended to help policy makers, resource managers, educators, service providers, and...

Proposed Continental Operations Range. United States Air Force.

Science.gov (United States)

1974-06-01

sihject to the lesser constraints of COR East. This will occur as voon as comunications capability and radar surveillance will ,*.rr1t. The proposed COR...These communities are found at eleva- tionz mostly above the Pinon-Juniper Woodland comunities , or often in close association with them. The principal...species are relict or may have aesthe- tic and scientific value; (6) economic or recreational importance; and (7) various combinations of the above. The

Development of broadleaved woodland on colliery and open pit coal mines in the United Kingdom

International Nuclear Information System (INIS)

Humphries, R.N.; McQuire, G.E.

1994-01-01

Broadleaved woodland is an important land use and vegetation type in the United Kingdom (UK), and potentially the most effective landscape and restoration treatment for colliery waste tips and open pit coal sites. A field-based national survey of collieries in England and Wales in 1986 and 1987 showed that establishment was satisfactory in only half of the schemes, and growth was deemed satisfactory in less than one-fifth. There are standard forestry practices whereby stock quality can be assured, and herbaceous vegetation controlled or eliminated by the use of herbicides. During the restoration of the site, depending on choice of species, adequate soil water can be provided by the selection of appropriate soil types and thicknesses, and adoption of appropriate soil handling and decompaction practices. The low affinity of the plantations with local and regional types was partly due to the planting of non-native species and partly due to the failure to match species with site and soil characteristics. There is no reason why woodlands of a local and regional character cannot be established by planting the associated species. A matrix of fast-growing tree and/or shrub species should be used to promote early woodland development. These would be removed during normal management which is essential for the ultimate success of the woodland. Planting schemes should also incorporate woodland structural elements and understory and ground flora species. Provided that these measures are fully implemented, significant improvements in establishment, growth, and woodland development on restored sites should be achieved

Eddy flux and leaf level measurements of biogeni VOC emissions from Mopane woodland of Botswana

NARCIS (Netherlands)

Greenberg, J.P.; Guenter, A.; Harley, P.; Otter, L.; Veenendaal, E.M.; Hewwit, C.N.; James, A.E.; Owen, S.M.

2003-01-01

Biogenic volatile organic compound (BVOC) emissions were measured in a mopane woodland near Maun, Botswana in January–February 2001 as part of SAFARI 2000. This landscape is comprised of more than 95% of one woody plant species, Colophospermum mopane (Caesalpinaceae). Mopane woodlands extend over a

Historical mapping reveals causes and temporal patterns of woodland contraction in Austur-Skaftafellssýsla from the 12th century AD to present

Science.gov (United States)

Sigurmundsson, Friðþór S.; Gísladóttir, Guðrún; Erlendsson, Egill; Þorbjarnarson, Höskuldur

2016-04-01

Land-cover changes in Iceland over the last millennium encompass birch (Betula pubescens) woodland depletion and extensive soil erosion. Yet few studies have focused on spatial change of birch woodland coverage in Iceland over centuries and why and how the woodland depletion took place. The main objectives of this study are: (1) to map the woodland distribution today in Austur-Skaftafellssýsla (3041 km2) in southern Iceland; (2) to map woodland holdings over a period of 900 years from eleventh. AD 1100 to the early 20th century; (3) explain the relative impacts of socio-economic and natural forces on woodland cover over this period. We use a combined approach of historical reconstruction from diverse written archives, GIS techniques and field work. The woodland in Austur-Skaftafellssýsla now covers 73.2 km2 (2.5% of the study area). The woodland holdings, 44 in total, are regularly listed in the church inventories from 1179 to 1570 and are owned by the church. In the first complete register for the district in 1641 the woodland holdings were 73, owned and used by 58 estates, and distributed across Austur-Skaftafellssýsla. All the main patches of woodland remain today, with the exception of four minor woodlands which were exhausted near the end of the 19th century. The woodland was used for firewood and charcoal making as well as grazing during the study period but, crucially, in most cases only one estate had authority over each holding, none were commons. The main driving force behind the development of woodlands was socio-economic, rather than natural, where the form of ownership was fundamental for the fate of the woodland. Harsh climate and volcanism were not directly responsible for woodland depletion. The latter half of the 19th century was the period of greatest woodland loss. This period coincides with considerable expansion in livestock numbers, especially sheep and associated all year around grazing, at a time when the Little Ice Age culminated in

Ecology and management of a remnant Brachystegia Speciformis (Miombo) Woodland in North Eastern Soutpansberg, Limpopo Province

CSIR Research Space (South Africa)

Saidi, AT

2006-01-01

Full Text Available is the season for re-sprouting. Fresh-brown to pink leaves start to grow. The fruit pods also dry and start to burst open to release the seeds. These seasonal changes are in line with what happens in miombo woodlands elsewhere on the continent. Mafuta (2000...) describes miombo woodlands as deciduous, losing leaves in winter and developing full foliage in summer. Palmer and Pitman (1972), describe similar seasonal changes, and further observe that pink and purple new foliage of miombo woodlands presents a great...

Greenhouse gas emissions from Savanna ( Miombo ) woodlands ...

African Journals Online (AJOL)

Natural vegetation represents an important sink for greenhouse gases (GHGs); however, there is relatively little information available on emissions from southern African savannas. The effects of clearing savanna woodlands for crop production on soil fluxes of N2O, CO2 and CH4 were studied on clay (Chromic luvisol) and ...

Using a State-and-Transition Approach to Manage Endangered Eucalyptus albens (White Box) Woodlands

Science.gov (United States)

Spooner, Peter G.; Allcock, Kimberly G.

2006-11-01

Eucalyptus albens (White Box) woodlands are among the most poorly conserved and threatened communities in Australia. Remnants are under further threat from stock grazing, deteriorating soil conditions, weed invasion, and salinity. There is an urgent need to restore degraded White Box and other woodland ecosystems to improve landscape function. However, there is still a poor understanding of the ecology of degraded woodland ecosystems in fragmented agricultural landscapes, and consequently a lack of precise scientific guidelines to manage these ecosystems in a conservation context. State and Transition Models (STMs) have received a great deal of attention, mainly in rangeland applications, as a suitable framework for understanding the ecology of complex ecosystems and to guide management. We have developed a STM for endangered White Box woodlands and discuss the merits of using this approach for land managers of other endangered ecosystems. An STM approach provides a greater understanding of the range of states, transitions, and thresholds possible in an ecosystem, and provides a summary of processes driving the system. Importantly, our proposed STM could be used to clarify the level of “intactness” of degraded White Box woodland sites, and provide the impetus to manage different states in complementary ways, rather than attempting to restore ecosystems to one pristine stable state. We suggest that this approach has considerable potential to integrate researcher and land manager knowledge, focus future experimental studies, and ultimately serve as a decision support tool in setting realistic and achievable conservation and restoration goals.

A condition metric for Eucalyptus woodland derived from expert evaluations.

Science.gov (United States)

Sinclair, Steve J; Bruce, Matthew J; Griffioen, Peter; Dodd, Amanda; White, Matthew D

2018-02-01

The evaluation of ecosystem quality is important for land-management and land-use planning. Evaluation is unavoidably subjective, and robust metrics must be based on consensus and the structured use of observations. We devised a transparent and repeatable process for building and testing ecosystem metrics based on expert data. We gathered quantitative evaluation data on the quality of hypothetical grassy woodland sites from experts. We used these data to train a model (an ensemble of 30 bagged regression trees) capable of predicting the perceived quality of similar hypothetical woodlands based on a set of 13 site variables as inputs (e.g., cover of shrubs, richness of native forbs). These variables can be measured at any site and the model implemented in a spreadsheet as a metric of woodland quality. We also investigated the number of experts required to produce an opinion data set sufficient for the construction of a metric. The model produced evaluations similar to those provided by experts, as shown by assessing the model's quality scores of expert-evaluated test sites not used to train the model. We applied the metric to 13 woodland conservation reserves and asked managers of these sites to independently evaluate their quality. To assess metric performance, we compared the model's evaluation of site quality with the managers' evaluations through multidimensional scaling. The metric performed relatively well, plotting close to the center of the space defined by the evaluators. Given the method provides data-driven consensus and repeatability, which no single human evaluator can provide, we suggest it is a valuable tool for evaluating ecosystem quality in real-world contexts. We believe our approach is applicable to any ecosystem. © 2017 State of Victoria.

Restoration of midwestern oak woodlands and savannas

Science.gov (United States)

Dan C. Dey; John M. Kabrick

2015-01-01

There are various definitions for savanna and woodland in the ecological literature. Characteristic elements of each community are broadly defined and often overlap according to the authorities (Curtis 1959; Nuzzo 1986; Nelson 2010). Some confusion is inevitable when categorizing what is in reality a continuum of states from prairie to forest in which there can be much...

[Genetical control of the allozymes in juniper (Juniperus excelsa Bieb.) of the Crimea].

Science.gov (United States)

Korshikov, I I; Nikolaeva, A V

2007-01-01

Genetical control of nine enzyme systems has been studied in preserved juniper species (Juniperus excelsa Bieb.) of the natural population of the mountain Crimea. Isozymes were extracted from the haploid seed endosperms and separated elecrophoretically. As a result 16 loci have been identified. Fourteen of them were polymorphic (14--Gdh, Got-1, Mdh-1, Mdh-2, Mdh-3, Acp-1, Acp-2, Acp-3, Lap-1, Dia-1, Fdh, Sod-1, Sod-2, Sod-3). Analysis of the allele segragation of the heterozygous trees confirmed their monogenic inheritance.

Habitat fragmentation impacts mobility in a common and widespread woodland butterfly: do sexes respond differently?

Directory of Open Access Journals (Sweden)

Bergerot Benjamin

2012-04-01

Full Text Available Abstract Background Theory predicts a nonlinear response of dispersal evolution to habitat fragmentation. First, dispersal will be favoured in line with both decreasing area of habitat patches and increasing inter-patch distances. Next, once these inter-patch distances exceed a critical threshold, dispersal will be counter-selected, unless essential resources no longer co-occur in compact patches but are differently scattered; colonization of empty habitat patches or rescue of declining populations are then increasingly overruled by dispersal costs like mortality risks and loss of time and energy. However, to date, most empirical studies mainly document an increase of dispersal associated with habitat fragmentation. We analyzed dispersal kernels for males and females of the common, widespread woodland butterfly Pararge aegeria in highly fragmented landscape, and for males in landscapes that differed in their degree of habitat fragmentation. Results The male and female probabilities of moving were considerably lower in the highly fragmented landscapes compared to the male probability of moving in fragmented agricultural and deciduous oak woodland landscapes. We also investigated whether, and to what extent, daily dispersal distance in the highly fragmented landscape was influenced by a set of landscape variables for both males and females, including distance to the nearest woodland, area of the nearest woodland, patch area and abundance of individuals in the patch. We found that daily movement distance decreased with increasing distance to the nearest woodland in both males and females. Daily distances flown by males were related to the area of the woodland capture site, whereas no such effect was observed for females. Conclusion Overall, mobility was strongly reduced in the highly fragmented landscape, and varied considerably among landscapes with different spatial resource distributions. We interpret the results relative to different cost

Winter precipitation effect in a mid-latitude temperature-limited environment: the case of common juniper at high elevation in the Alps

International Nuclear Information System (INIS)

Pellizzari, Elena; Pividori, Mario; Carrer, Marco

2014-01-01

Common juniper (Juniperus communis L.) is by far the most widespread conifer in the world. However, tree-ring research dealing with this species is still scarce, mainly due to the difficulty in crossdating associated with the irregular stem shape with strip-bark growth form in older individuals and the high number of missing and wedging rings. Given that many different species of the same genus have been successfully used in tree-ring investigations and proved to be reliable climate proxies, this study aims to (i) test the possibility to successfully apply dendrochronological techniques on common juniper growing above the treeline and (ii) verify the climate sensitivity of the species with special regard to winter precipitation, a climatic factor that generally does not affect tree-ring growth in all Alpine high-elevation tree species. Almost 90 samples have been collected in three sites in the central and eastern Alps, all between 2100 and 2400 m in elevation. Despite cross-dating difficulties, we were able to build a reliable chronology for each site, each spanning over 200 years. Climate-growth relationships computed over the last century highlight that juniper growth is mainly controlled by the amount of winter precipitation. The high variability of the climate-growth associations among sites, corresponds well to the low spatial dependence of this meteorological factor. Fairly long chronologies and the presence of a significant precipitation signal open up the possibility to reconstruct past winter precipitation. (letter)

Effects of juniper essential oil on growth performance, some rumen protozoa, rumen fermentation and antioxidant blood enzyme parameters of growing Saanen kids.

Science.gov (United States)

Yesilbag, D; Biricik, H; Cetin, I; Kara, C; Meral, Y; Cengiz, S S; Orman, A; Udum, D

2017-10-01

This study aimed to evaluate the effects of juniper essential oil on the growth performance, rumen fermentation parameters, rumen protozoa population, blood antioxidant enzyme parameters and faecal content in growing Saanen kids. Thirty-six male Saanen kids (36 ± 14 days of age) were used in the study. Each group consisted of 9 kids. The control group (G1) was fed with a diet that consisted of the above concentrated feed and oat hay, whereas the experimental groups consumed the same diet but with the concentrated feed uniformly sprayed with juniper essential oil 0.4 ml/kg (G2), 0.8 ml/kg (G3) or 2 ml/kg (G4). There were no differences (p > 0.05) in live weight, live weight gain or feed consumption between the control and experimental groups. There was a significant improvement (p rumen pH, rumen volatile fatty acid (VFA) profile or faecal pH of the control and experimental groups. The rumen NH 3 N values were similar at the middle and end of the experiment, but at the start of the experiment, the rumen NH 3 N values differed between the control and experimental groups (p < 0.05). The faecal score value was significantly (p < 0.05) decreased in the experimental groups. The addition of juniper essential oil supplementation to the rations caused significant effects on the kids' antioxidant blood parameters. Although the superoxide dismutase (SOD) activity, total antioxidant capacity (TAC) and catalase values were significantly (p < 0.05) increased in the experimental groups (G2, G3 and G4), especially group G4, the blood glutathione peroxidase (GPX) value significantly decreased in the experimental groups. The results of this study suggest that supplementation of juniper oil is more effective on antioxidant parameters than on performance parameters and may be used as a natural antioxidant product. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Data Report: Meteorological and Evapotranspiration Data from Sagebrush and Pinyon Pine/Juniper Communities at Pahute Mesa, Nevada National Security Site, 2011-2012

Energy Technology Data Exchange (ETDEWEB)

Jasoni, Richard L [DRI; Larsen, Jessica D [DRI; Lyles, Brad F. [DRI; Healey, John M [DRI; Cooper, Clay A [DRI; Hershey, Ronald L [DRI; Lefebre, Karen J [DRI

2013-04-01

Pahute Mesa is a groundwater recharge area at the Nevada National Security Site. Because underground nuclear testing was conducted at Pahute Mesa, groundwater recharge may transport radionuclides from underground test sites downward to the water table; the amount of groundwater recharge is also an important component of contaminant transport models. To estimate the amount of groundwater recharge at Pahute Mesa, an INFIL3.0 recharge-runoff model is being developed. Two eddy covariance (EC) stations were installed on Pahute Mesa to estimate evapotranspiration (ET) to support the groundwater recharge modeling project. This data report describes the methods that were used to estimate ET and collect meteorological data. Evapotranspiration was estimated for two predominant plant communities on Pahute Mesa; one site was located in a sagebrush plant community, the other site in a pinyon pine/juniper community. Annual ET was estimated to be 310±13.9 mm for the sagebrush site and 347±15.9 mm for the pinyon pine/juniper site (March 26, 2011 to March 26, 2012). Annual precipitation measured with unheated tipping bucket rain gauges was 179 mm at the sagebrush site and 159 mm at the pinyon pine/juniper site. Annual precipitation measured with bulk precipitation gauges was 222 mm at the sagebrush site and 227 mm at the pinyon pine/juniper site (March 21, 2011 to March 28, 2012). A comparison of tipping bucket versus bulk precipitation data showed that total precipitation measured by the tipping bucket rain gauges was 17 to 20 percent lower than the bulk precipitation gauges. These differences were most likely the result of the unheated tipping bucket precipitation gauges not measuring frozen precipitation as accurately as the bulk precipitation gauges. In this one-year study, ET exceeded precipitation at both study sites because estimates of ET included precipitation that fell during the winter of 2010-2011 prior to EC instrumentation and the precipitation gauges started

Quantifying the transient carbon dynamics of ecosystem scale carbon cycle responses to piñon pine mortality using a large-scale experimental manipulation, remote sensing and model-data fusion

Science.gov (United States)

Litvak, M. E.; Hilton, T. W.; Krofcheck, D. J.; Fox, A. M.; Robinson, E.; McDowell, N. G.; Rahn, T.; Sinsabaugh, R.

2012-12-01

The southwestern United States experienced an extended drought from 1999-2002 which led to widespread coniferous tree mortality throughout New Mexico, Arizona, Utah and Colorado. Piñon-juniper (PJ) woodlands, which occupy 24 million ha throughout the Southwest, proved to be extremely vulnerable to this drought, experiencing 40 to 95% mortality of piñon pine (Pinus edulis) and 2-25% mortality of juniper (Juniperus monosperma) in less than 3 years (Breshears et al., 2005). Understanding the response trajectories of these woodlands is crucial given that climate projections for the region suggest that episodic droughts, such as the one correlated with these recent conifer mortality, are likely to increase in frequency and severity and to expand northward. We are using a combination of eddy covariance, soil respiration, sap flow and biomass carbon pool measurements made at: (i) an undisturbed PJ woodland (control) in central New Mexico and at a manipulation site within 2 miles of the control where all piñon trees greater than 7 cm diameter at breast height within the 4 ha flux footprint were girdled (decreasing LAI by ~ 1/3) to quantify the response of ecosystem carbon and water dynamics in PJ woodlands to widespread piñon mortality. As expected, piñon mortality triggered an abrupt shift in carbon stocks from productive biomass to detritus, leading to a 25% decrease in gross primary production, and >50% decrease in net ecosystem production in the two years following mortality. Because litter and course woody debris are slow to decompose in these semiarid environments, ecosystem respiration initially decreased following mortality, and only increased two years post mortality following a large monsoon precipitation event. In the three years following mortality, reduced competition for water in these water limited ecosystems and increased light availability has triggered compensatory growth in understory vegetation observed in both remote sensing and ground

77 FR 33560 - Woodland Rail, LLC-Acquisition and Operation Exemption-Line of Maine Central Railroad Co.

Science.gov (United States)

2012-06-06

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35628] Woodland Rail, LLC... United States. The end points of the Line are at engineering station 64+17 in Baileyville and engineering... Woodland Junction, Me., which is engineering station 363+45, and engineering station 393+37, and another...

Socia preferences to Mopane woodland management options: A ...

African Journals Online (AJOL)

Socia preferences to Mopane woodland management options: A case study from Southern Zimbabwe. TA Gondo, C Musvoto, T Mujawo. Abstract. No Abstract. Discovery and Innovation Vol. 19 (1&2) 2007: pp.4-14. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

As Long as it is Not My Land: Landowners and Oak Woodland Conservation in Spain and California

Science.gov (United States)

Huntsinger, L.; Oviedo, J. L.; Plieninger, T.

2009-04-01

In Spain and California, landowners have a crucial role to play in the conservation of oak woodlands. The value of environmental services from private oak woodlands used for extensive agriculture has drawn the attention of policymakers and conservationists, and policy strategies for maintenance of traditional extensive agriculture are emergent in both places. These strategies require landowner participation. Surveys of landowners in each place reveal similarities in management practices, goals, attitudes, and demographics, as well as some interesting points of divergence. Despite very different institutional and political contexts, landowner attitudes show some striking similarities. Both favor a degree of government protection of natural resources, but would prefer that this would not include regulation of activities on their own lands. With a relatively stable woodland ecologically, and a high rate of urban out-migration into woodland areas, the more visible initiatives in California today focus on landowner education, and tax relief for temporary or permanent restrictions on land conversion. Non-governmental organizations have taken an increasingly visible role in the brokering of purchased or donated land title restrictions for conservation. These programs have resulted in an apparent decline in oak harvest and some limitations on development, but have not often directly influenced regeneration or management on private lands. In contrast, with more stable patterns of population distribution and less stable woodland ecological dynamics, Spanish incentive programs approach regeneration and management issues more directly, with subsidies for oak planting and maintenance, and price advantages for the products of traditional agriculture. The results of a twenty-year longitudinal study in California show a shift towards an increasing focus on amenities by California oak woodland landowners, whether they are ranch owners with hundreds of hectares of woodland, or

Genetic restoration in the eastern collared lizard under prescribed woodland burning.

Science.gov (United States)

Neuwald, Jennifer L; Templeton, Alan R

2013-07-01

Eastern collared lizards of the Ozarks live in glades--open, rocky habitats embedded in a woodland matrix. Past fire suppression had made the woodlands a barrier to dispersal, leading to habitat destruction, fragmentation and local extinction. Reintroduced populations of lizards were subjected to 10 years of habitat fragmentation under continued fire suppression followed by twelve years of landscape restoration with prescribed burns. Prior to prescribed burning, genetic diversity decreased within glades and differentiation increased among glades. With woodland burning, genetic diversity within glades first decreased during an expanding colonization phase, but then increased as a dynamically stable metapopulation was established. Population differentiation among glades also stabilized in the metapopulation under weak isolation-by-distance. This study is one of the first to examine the genetic changes in a species of conservation concern throughout all the stages of decline and recovery and shows the importance of landscape-level restoration for maintaining the genetic integrity of populations. This study also demonstrates how mark-recapture and genetic data together can yield detailed insight into metapopulation dynamics that would be impossible from just one type of data alone. © 2013 John Wiley & Sons Ltd.

Restoring oak forest, woodlands and savannahs using modern silvicultural analogs to historic cultural fire regimes

Science.gov (United States)

Daniel C. Dey; Richard P. Guyette; Callie J. Schweitzer; Michael C. Stambaugh; John M. Kabrick

2015-01-01

Variability in historic fire regimes in eastern North America resulted in an array of oak savannahs, woodlands and forests that were dominant vegetation types throughout the region. In the past century, once abundant savannahs and woodlands have become scarce due to conversion to agriculture, or development of forest structure in the absence of fire. In addition, the...

Plant composition in oak savanna and woodland restoration at Prairie Fork Conservation Area in Missouri

Science.gov (United States)

Nadia E. Navarrete-Tindall; J.W. Van Sambeek; Jamie Coe; Warren Taylor

2007-01-01

The wooded areas of the Prairie Fork Conservation Area in central Missouri are typical of the oak/hickory forest/prairie transition zone that will require active management to restore pre-settlement, grass dominated savannas and open woodlands to improve habitat for wildlife. We initiated a management program to restore savannas and woodlands by reducing the midstory (...

Proposal to endorse the award of a contract for the supply of a juniper T320 network router

CERN Document Server

2003-01-01

This document concerns the award of a contract for the supply of a JUNIPER T320 Network Router. The Finance Committee is invited to endorse the CERN Management's decision to negotiate a contract with QWEST COMMUNICATION (USA) for the supply of a JUNIPER T320 Network Router for a total amount not exceeding 265 000 US dollars (350 000 Swiss francs). The Finance Committee is also requested to approve the negotiation of a maintenance contract for a value not exceeding 50 000 US dollars (66 000 Swiss francs) for three years and the option to purchase additional network interfaces for a value not exceeding 100 000 US dollars (132 000 Swiss francs) bringing the total amount to 415 000 US dollars (548 000 Swiss francs), not subject to revision. CERN's contribution will not exceed 90 000 Swiss francs. The amounts in Swiss francs have been calculated using the present rate of exchange. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: CA - 100%.

Vegetation Change in Blue Oak Woodlands in California

Science.gov (United States)

Barbara A. Holzman; Barbara H. Allen-Diaz

1991-01-01

A preliminary report of a statewide project investigating vegetation change in blue oak (Quercus douglasii) woodlands in California is presented. Vegetation plots taken in the 1930s, as part of a statewide vegetation mapping project, were relocated and surveyed. Species composition, cover and tree stand structure data from the earlier study were...

Land change in eastern Mediterranean wood-pasture landscapes: the case of deciduous oak woodlands in Lesvos (Greece).

Science.gov (United States)

Schaich, Harald; Kizos, Thanasis; Schneider, Stefan; Plieninger, Tobias

2015-07-01

In Mediterranean Europe, wood-pasture landscapes with oak woodlands as emblematic ecosystems are undergoing rapid land-use change, which may threaten their legacy as hotspots of biodiversity, ecosystem services, and cultural heritage. The objective of this study was to quantify land cover changes and transitions as well as the dynamics of oak woodland patterns and densities over 50 years in two municipalities at the center and edges of Quercus macrolepis distribution in Northern Lesvos (Greece). We used aerial photographs from 1960 and WorldView-2 satellite images from 2010 to process land cover maps and metrics, and to calculate oak canopy cover with a point-grid sampling approach. Spatiotemporal dynamics of land cover change were generally high--especially between oak woodlands and grass- and shrub-lands, resulting in a more heterogeneous and fragmented landscape in 2010. Surprisingly, oak woodland area remained stable with marginal losses in one study site and gains in the other one. Oak canopy cover increased by 8 and 9%. Spatial hotspots of change were mountainous and peripheral phrygana areas with expanding oak stands, as well as river valleys and near urban areas with expanding olive groves and grass- and shrublands in former complex cultivation and oak stands. We conclude that the parallel processes of abandonment of crop cultivation and intensification of livestock grazing have been less detrimental to oak woodlands than supposed. To ensure long-term persistence of oak woodlands in the face of ongoing rural depopulation and land-use intensification, environmental and agricultural policies should better address their specificities as anthropogenic habitats.

Land Change in Eastern Mediterranean Wood-Pasture Landscapes: The Case of Deciduous Oak Woodlands in Lesvos (Greece)

Science.gov (United States)

Schaich, Harald; Kizos, Thanasis; Schneider, Stefan; Plieninger, Tobias

2015-07-01

In Mediterranean Europe, wood-pasture landscapes with oak woodlands as emblematic ecosystems are undergoing rapid land-use change, which may threaten their legacy as hotspots of biodiversity, ecosystem services, and cultural heritage. The objective of this study was to quantify land cover changes and transitions as well as the dynamics of oak woodland patterns and densities over 50 years in two municipalities at the center and edges of Quercus macrolepis distribution in Northern Lesvos (Greece). We used aerial photographs from 1960 and WorldView-2 satellite images from 2010 to process land cover maps and metrics, and to calculate oak canopy cover with a point-grid sampling approach. Spatiotemporal dynamics of land cover change were generally high—especially between oak woodlands and grass- and shrub-lands, resulting in a more heterogeneous and fragmented landscape in 2010. Surprisingly, oak woodland area remained stable with marginal losses in one study site and gains in the other one. Oak canopy cover increased by 8 and 9 %. Spatial hotspots of change were mountainous and peripheral phrygana areas with expanding oak stands, as well as river valleys and near urban areas with expanding olive groves and grass- and shrublands in former complex cultivation and oak stands. We conclude that the parallel processes of abandonment of crop cultivation and intensification of livestock grazing have been less detrimental to oak woodlands than supposed. To ensure long-term persistence of oak woodlands in the face of ongoing rural depopulation and land-use intensification, environmental and agricultural policies should better address their specificities as anthropogenic habitats.

Supply of wood fuel from small-scale woodlands for small-scale heating

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-07-01

This report summarises the findings of a study aimed at stimulating a market for wood fuels. A desk study of harvesting in existing small woodland was conducted, and thirteen case studies covering early broadleaved thinnings, mixed broadleaved coppice, and crownwood, scrub and residues were examined to obtain information on woodland types, wood fuel supply, and combustion equipment. Details are given of the measurement of moisture content of woodchips and stacked roundwood, wood volume and green density, harvesting options, crop and site variables, and production and costs of wood fuels. Usage of wood fuels, and the drying of small roundwood was considered. (UK)

Effects of Feeding Garlic and Juniper Berry Essential Oils on Milk Fatty Acid Composition of Dairy Cows

Directory of Open Access Journals (Sweden)

Wen Zhu Yang

2016-01-01

Full Text Available Essential oils (EOs from plant extracts have been reported to have an antibacterial activity against gram-negative and gram-positive bacteria. Several of the gram-positive bacteria are involved in ruminal biohydrogenation of fatty acids (FAs, thus suggesting that feeding EOs could lower biohydrogenation of FA because of a decrease in the number of bacteria involved in that process. As a result, milk FA profiles are expected to be modified. In addition, monensin was approved as an antibiotic to be fed in dairy cattle, and it was reported that dairy cows supplemented with monensin produced milk containing higher concentration of 18:1 t10 and 18:1 t11. The objective of this study was to evaluate the effects of two EOs (garlic and juniper berry oils and monensin on FA profiles of milk fat. Four ruminally fistulated Holstein dairy cows were used in a 4 x 4 Latin square experiment. Cows were fed for ad libitum intake a total mixed ration without supplementation (control, or supplemented with monensin (330 mg/head per day, garlic oil (5 g/head per day, or juniper berry oil (2 g/head per day. The FA composition of saturated, monounsaturated, or polyunsaturated was not affected by supplementation of EO and monensin. However, proportion of conjugated linoleic acid trans 10, cis 12 (CLA t10, c12 was higher ( P < 0.05 for cows fed EO or monensin than for control cows. Supplementation of monensin increased ( P < 0.05 the proportion of total trans FA compared with the control. These results indicate that supplementation of the dairy cow diet with garlic or juniper berry EO or monensin had the potential to increase the proportion of CLA t10, c12 in milk fat with minimal overall effects on FA of milk fat. The results also confirm the increase of 18:1 t10 in milk fat by feeding monensin to dairy cows.

Woodland caribou management in Alberta: historical perspectives and future opportunities

Directory of Open Access Journals (Sweden)

Elston H. Dzus

2007-04-01

Full Text Available Woodland caribou conservation has been the topic of much debate for the past few decades. By the late 1970s there was growing concern about declining woodland caribou populations and the interaction between industrial activities and woodland caribou. Initial concerns led to the closure of the licensed hunting season in 1981. Early confrontation between government and industry in the late 1980s transformed into a series of evolving collaborative ventures. Improving our understanding of the basic ecology of woodland caribou in Alberta was at the center of early research efforts; more recent studies have examined the effects of industrial activities on caribou and effectiveness of various mitigation factors. Despite having amassed an impressive body of information from a research and monitoring perspective, progress on implementing effective management actions has been less dramatic. Industry has endured significant costs implementing a variety of perceived conservation initiatives, but caribou populations continued to decline through the last few decades. While some parties feel more research is needed, there is growing consensus that changes to habitat as induced by human activities are important factors influencing current caribou declines. Predation is a proximate cause of most caribou mortality. Climate change mediated alterations to habitat and predator-prey interactions remain a key source of uncertainty relative to future caribou population trends. Management actions will need to deal with long term habitat changes associated with human land use and short term implications of increased predation. In 2005, the provincial minister responsible for caribou conservation responded to the draft 2004 recovery plan and created the Alberta Caribou Committee (ACC. The goal of the ACC is to maintain and recover woodland caribou in Alberta’s forest ecosystems while providing opportunities for resource development, following guidance provided by the

Engaging with peri-urban woodlands in England: the contribution to people's health and well-being and implications for future management.

Science.gov (United States)

O'Brien, Liz; Morris, Jake; Stewart, Amy

2014-06-12

In this paper we engage with debates concerning people and their contact with the natural environment as part of everyday life drawing on Irwin's ideas of co-construction and Gibson's theory of affordances. We focus on peri-urban woodlands in England as important places where people can interact with nature for health and well-being. Qualitative data were collected in situ via walks in the woods, focus group discussions and photo elicitation, with a sample of 49 people. These methods provide rich data on the wide range of meanings associated with woodlands that can have a perceived impact on people's health and well-being. The findings link to contemporary debates about health, well-being and ecosystem services. We explore the inter-play between attributes of the physical environment and the range of facilities provided to enable access, social interactions and the benefits people attribute to their woodland experiences. We conclude that peri-urban woodlands can clearly contribute to self-reported health and well-being in multiple ways, and that organized activities can be important for those who face barriers to accessing woodlands. A strong message emerging from the research is the opportunity afforded by woodlands for social connections with others, as well as the provision of a range of sensory benefits and opportunities to observe and enjoy seasonal change in woodlands. Mental restoration via connection with nature also emerged as important, confirming previous research.

Phytoecological study of Tetraclinis articulata in the woodland of ...

African Journals Online (AJOL)

The Mediterranean flora is definitely considered as an exceptional diversity that deserves particular attention to be conserved. This work aims to quantify the floristic diversity of Tetraclinis articulata of Beni Affane located at the woodland of Sdamas Chergui (Tiaret, Algeria). The factorial analysis of correspondences allowed ...

The colonisation of woodland gaps by ferns and horsetails

NARCIS (Netherlands)

Bremer, P.

2010-01-01

In the Voorsterbos, a planted woodland on a former sea-floor (the Netherlands), artificial gaps within stands of Fagus sylvatica on boulder clay were monitored for five or six years after cutting. Ten fern species and three species of horsetail established in these gaps, with Dryopteris cristata,

Four millennia of woodland structure and dynamics at the Arctic treeline of eastern Canada.

Science.gov (United States)

Auger, Sarah; Payette, Serge

2010-05-01

Paleoecological analysis using complementary indicators of vegetation and soil can provide spatially explicit information on ecological processes influencing trajectories of long-term ecosystem change. Here we document the structure and dynamics of an old-growth woodland before and after its inception 1000 years ago. We infer vegetation and soil characteristics from size and age distributions of black spruce (Picea mariana (Mill.) B.S.P.), soil properties, plant fossils, and paleosols. Radiocarbon ages of charcoal on the ground and in the soil indicate that the fire return interval was approximately 300 years between 2750 and 1000 cal. yr BP. No fire evidence was found before and after this period despite the presence of spruce since 4200 cal. yr BP. The size structures of living and dead spruce suggest that the woodland is in equilibrium with present climate in absence of fire. Tree establishment and mortality occurred regularly since the last fire event around 950 cal. yr BP. Both layering and occasional seeding have contributed to stabilize the spatial distribution of spruce over the past 1000 years. Since initial afforestation, soil development has been homogenized by the changing spatial distribution of spruce following each fire. We conclude that the history of the woodland is characterized by vegetation shifts associated with fire and soil disturbances and by millennial-scale maintenance of the woodland's structure despite changing climatic conditions.

Predicting patch occupancy in fragmented landscapes at the rangewide scale for an endangered species: an example of an American warbler

KAUST Repository

Collier, Bret A.

2011-08-25

AIM: Our objective was to identify the distribution of the endangered golden-cheeked warbler (Setophaga chrysoparia) in fragmented oak-juniper woodlands by applying a geoadditive semiparametric occupancy model to better assist decision-makers in identifying suitable habitat across the species breeding range on which conservation or mitigation activities can be focused and thus prioritize management and conservation planning. LOCATION: Texas, USA. METHODS: We used repeated double-observer detection/non-detection surveys of randomly selected (n = 287) patches of potential habitat to evaluate warbler patch-scale presence across the species breeding range. We used a geoadditive semiparametric occupancy model with remotely sensed habitat metrics (patch size and landscape composition) to predict patch-scale occupancy of golden-cheeked warblers in the fragmented oak-juniper woodlands of central Texas, USA. RESULTS: Our spatially explicit model indicated that golden-cheeked warbler patch occupancy declined from south to north within the breeding range concomitant with reductions in the availability of large habitat patches. We found that 59% of woodland patches, primarily in the northern and central portions of the warbler\\'s range, were predicted to have occupancy probabilities ≤0.10 with only 3% of patches predicted to have occupancy probabilities >0.90. Our model exhibited high prediction accuracy (area under curve = 0.91) when validated using independently collected warbler occurrence data. MAIN CONCLUSIONS: We have identified a distinct spatial occurrence gradient for golden-cheeked warblers as well as a relationship between two measurable landscape characteristics. Because habitat-occupancy relationships were key drivers of our model, our results can be used to identify potential areas where conservation actions supporting habitat mitigation can occur and identify areas where conservation of future potential habitat is possible. Additionally, our results can be

Firewood, food and human niche construction: the potential role of Mesolithic hunter-gatherers in actively structuring Scotland's woodlands

Science.gov (United States)

Bishop, Rosie R.; Church, Mike J.; Rowley-Conwy, Peter A.

2015-01-01

Over the past few decades the potential role of Mesolithic hunter-gatherers in actively constructing their own niches, through the management of wild plants, has frequently been discussed. It is probable that Mesolithic hunter-gatherers systematically exploited specific woodland resources for food and fuel and influenced the 'natural' abundance or distribution of particular species within Mesolithic environments. Though there has been considerable discussion of the pollen evidence for potential small-scale human-woodland manipulation in Mesolithic Scotland, the archaeobotanical evidence for anthropogenic firewood and food selection has not been discussed in this context. This paper assesses the evidence for the active role of Mesolithic hunter-gatherer communities in systematically exploiting and managing woodlands for food and fuel in Scotland. While taphonomic factors may have impacted on the frequency of specific species in archaeobotanical assemblages, it is suggested that hunter-gatherers in Mesolithic Scotland were systematically using woodland plants, and in particular hazel and oak, for food and fuel. It is argued that the pollen evidence for woodland management is equivocal, but hints at the role of hunter-gatherers in shaping the structure of their environments, through the maintenance or creation of woodland clearings for settlement or as part of vegetation management strategies. It is proposed that Mesolithic hunter-gatherers may have actively contributed to niche construction and that the systematic use of hazel and oak as a fuel may reflect the deliberate pruning of hazel trees to increase nut-yields and the inadvertent - or perhaps deliberate - coppicing of hazel and oak during greenwood collection.

Canopy, snow, and lichens on woodland caribou range in southeastern Manitoba

Directory of Open Access Journals (Sweden)

James A. Schaefer

1996-01-01

Full Text Available I examined the relationships among snow cover (api, lichen abundance, and canopy composition on the range of the Aikens Lake population of woodland caribou (Rangifer tarandus caribou in southeastern Manitoba. Percent cover of forage lichens (Cladina spp. was positively correlated with maximum total thickness and with maximum vertical hardness of api. Mixed communities of trembling aspen (Populus tremuloides, spruce (Picea spp., and balsam fir (Abies balsamea showed the most favourable nival conditions for caribou but had low lichen abundance; those dominated by jack pine (Pinus banksiana were the converse. The results suggest an energetic compromise for woodland caribou when foraging for terrestrial lichens. During winter, caribou exhibited significant selection for jack pine communities whereas mixed communities were avoided.

A National Perspective on Women Owning Woodlands (WOW) Networks

Science.gov (United States)

Huff, Emily S.

2017-01-01

This article provides a national overview of women owning woodlands (WOW) networks and the barriers and successes they encounter. Qualitative interview data with key network leaders were used for increasing understanding of how these networks operate. Network leaders were all connected professionally, and all successful WOW networks involved…

Engaging with Peri-Urban Woodlands in England: The Contribution to People’s Health and Well-Being and Implications for Future Management

Science.gov (United States)

O’Brien, Liz; Morris, Jake; Stewart, Amy

2014-01-01

In this paper we engage with debates concerning people and their contact with the natural environment as part of everyday life drawing on Irwin’s ideas of co-construction and Gibson’s theory of affordances. We focus on peri-urban woodlands in England as important places where people can interact with nature for health and well-being. Qualitative data were collected in situ via walks in the woods, focus group discussions and photo elicitation, with a sample of 49 people. These methods provide rich data on the wide range of meanings associated with woodlands that can have a perceived impact on people’s health and well-being. The findings link to contemporary debates about health, well-being and ecosystem services. We explore the inter-play between attributes of the physical environment and the range of facilities provided to enable access, social interactions and the benefits people attribute to their woodland experiences. We conclude that peri-urban woodlands can clearly contribute to self-reported health and well-being in multiple ways, and that organized activities can be important for those who face barriers to accessing woodlands. A strong message emerging from the research is the opportunity afforded by woodlands for social connections with others, as well as the provision of a range of sensory benefits and opportunities to observe and enjoy seasonal change in woodlands. Mental restoration via connection with nature also emerged as important, confirming previous research. PMID:24927035

Engaging with Peri-Urban Woodlands in England: The Contribution to People’s Health and Well-Being and Implications for Future Management

Directory of Open Access Journals (Sweden)

Liz O'Brien

2014-06-01

Full Text Available In this paper we engage with debates concerning people and their contact with the natural environment as part of everyday life drawing on Irwin’s ideas of co-construction and Gibson’s theory of affordances. We focus on peri-urban woodlands in England as important places where people can interact with nature for health and well-being. Qualitative data were collected in situ via walks in the woods, focus group discussions and photo elicitation, with a sample of 49 people. These methods provide rich data on the wide range of meanings associated with woodlands that can have a perceived impact on people’s health and well-being. The findings link to contemporary debates about health, well-being and ecosystem services. We explore the inter-play between attributes of the physical environment and the range of facilities provided to enable access, social interactions and the benefits people attribute to their woodland experiences. We conclude that peri-urban woodlands can clearly contribute to self-reported health and well-being in multiple ways, and that organized activities can be important for those who face barriers to accessing woodlands. A strong message emerging from the research is the opportunity afforded by woodlands for social connections with others, as well as the provision of a range of sensory benefits and opportunities to observe and enjoy seasonal change in woodlands. Mental restoration via connection with nature also emerged as important, confirming previous research.

Wilderness and woodland ranchers in California: A total income case study of public grazing permits and their impacts on conservation

Science.gov (United States)

Oviedo Pro, J. L.; Huntsinger, L.; Campos, P.; Caparros, A.

2009-04-01

Mediterranean woodlands in California are managed as agro-silvo-pastoral systems producing a number of commercial products as well as a huge variety of environmental services, including private amenities for the landowner. In many parts of the woodlands, grazing on government owned (public) lands has traditionally had an important role in private ranching. In recent decades the risk of conversion to alternative uses (such as urban development or vineyards) has threatened these woodlands due to the increasing opportunity costs of capital. Understanding the economy of these woodlands and the potential effects of public grazing policies on the total income perceived by the landowner is crucial when considering strategies attempting to slow or stop land use change. However, traditional cash-flow analyses are lacking crucial information needed to understand all the elements that have an important role in the economic decisions that landowners make about their woodlands. For more than half a century, the use of public lands by private ranchers has been one of the most controversial debates in the American west. Wilderness conservationist groups have denounced grazing as destructive and argue for the removal of any kind of livestock. Ranchers have fought for their right to hold public grazing leases, arguing that they are crucial for the continuity of private ranching and consequently for the conservation of extensive rangeland habitat that otherwise could be converted to alternative uses. In this study, we apply the Agroforestry Accounting System (AAS) methodology to a California oak woodland case study to estimate the total private income generated in an accounting period. The presented case study is characterized by a household economy with self-employed labour and with part of the grazing dependent on public land leases. The AAS methodology extends traditional cash-flow analysis in order to estimate the total private income that would accurately explain the woodland

Interaction between fires and elephants in relation to vegetation structure and composition of miombo woodlands in northern Mozambique

Science.gov (United States)

Ribeiro, Natasha Sofia

Miombo woodlands represent one of the most important dry deciduous ecosystems in southern Africa. They provide goods and services for over 80% of the population in the sub-continent. The ecology of this important ecosystem is strongly defined by the trio climate-fire-herbivory. Thus, miombo woodlands have a key role in the regional, and the global, energy, water and carbon balances. Niassa Reserve located in northern Mozambique, embodies the largest and most pristine conservation area of miombo woodlands in the region. It was left abandoned for almost twenty years of armed conflict in Mozambique. Currently it has the lowest human population and the highest density of elephants within miombo woodlands in the country. Fires occur every year within Niassa Reserve. Thus, Niassa Reserve represents a key area to investigate the relationships between vegetation and environmental drivers, a crucial question in miombo woodlands. The goal of this study is to contribute to the understanding of the vegetation dynamics in relation to rainfall, fire and herbivory by elephants. To accomplish this goal, I used an innovative approach within miombo woodlands that couples field and remote sensing data. Field data collection aimed to gather information on woody species composition, structure and production (measured as biomass and leaf area index). Production data was used to calibrate remote sensing data and address large-scale variations in woody vegetation production. The results from this study indicate that there is a gradient of decreasing fire frequency, elephant density and rainfall and increasing woody production from east to west of Niassa Reserve. There is also a varied species composition along the same direction. These results provide information for ecological models predicting ecosystem dynamics under environmental changing conditions. Regionally, this study contributes to the understanding of the fundamental functioning of miombo woodlands and the associated driving

Urbanization level and woodland size are major drivers of woodpecker species richness and abundance.

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Lukasz Myczko

Full Text Available Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species.

Urbanization level and woodland size are major drivers of woodpecker species richness and abundance.

Science.gov (United States)

Myczko, Lukasz; Rosin, Zuzanna M; Skórka, Piotr; Tryjanowski, Piotr

2014-01-01

Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland) in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species.

Will ecosystem management supply woodland caribou habitat in northwestern Ontario?

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David L. Euler

1998-03-01

Full Text Available Ecosystem management is emerging as an important concept in managing forests. Although the basic conceptual idea is not new, important defining principles are developing that elucidate some of the specific attributes of ecosystem management. These principles include: the maintenance of all ecosystems in the managed forest, rhe emulation of natural disturbance patterns on rhe landscape and the insurance that structure and function of forested ecosystems are conserved. Forest management has an impact on woodland caribou (Rangifer tarandus caribou, although the presence of wolves (Canis lupus and moose (Alces alces in the same northern ecosystems also affects the caribou-forestry interacrion. Specific management for caribou as a featured species has been proposed, based on managing large landscape blocks. Ecosystem management would also produce habitat in a manner that might accomplish the goal of conserving woodland caribou as well as maintaining other important ecosystem functions.

Decision-support tool for management of miombo woodlands: a ...

African Journals Online (AJOL)

The model complexity is well adapted to the data quality and abundance, and it is dependent on proxies of some main drivers of the dynamic processes. The development of the matrix model is a step forward facilitating better decisions in the management of miombo woodlands. However, data ranges used for calibrating ...

Estimating wood volume from canopy area in deciduous woodlands ...

African Journals Online (AJOL)

In this study we tested the predictive ability of canopy area in estimating wood volume in deciduous woodlands of Zimbabwe. The study was carried out in four sites of different climatic conditions. We used regression analysis to statistically quantify the prediction of wood volume from canopy area at species and stand level ...

Multi-scale associations between vegetation cover and woodland bird communities across a large agricultural region.

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Karen Ikin

Full Text Available Improving biodiversity conservation in fragmented agricultural landscapes has become an important global issue. Vegetation at the patch and landscape-scale is important for species occupancy and diversity, yet few previous studies have explored multi-scale associations between vegetation and community assemblages. Here, we investigated how patch and landscape-scale vegetation cover structure woodland bird communities. We asked: (1 How is the bird community associated with the vegetation structure of woodland patches and the amount of vegetation cover in the surrounding landscape? (2 Do species of conservation concern respond to woodland vegetation structure and surrounding vegetation cover differently to other species in the community? And (3 Can the relationships between the bird community and the woodland vegetation structure and surrounding vegetation cover be explained by the ecological traits of the species comprising the bird community? We studied 103 woodland patches (0.5 - 53.8 ha over two time periods across a large (6,800 km(2 agricultural region in southeastern Australia. We found that both patch vegetation and surrounding woody vegetation cover were important for structuring the bird community, and that these relationships were consistent over time. In particular, the occurrence of mistletoe within the patches and high values of woody vegetation cover within 1,000 ha and 10,000 ha were important, especially for bird species of conservation concern. We found that the majority of these species displayed similar, positive responses to patch and landscape vegetation attributes. We also found that these relationships were related to the foraging and nesting traits of the bird community. Our findings suggest that management strategies to increase both remnant vegetation quality and the cover of surrounding woody vegetation in fragmented agricultural landscapes may lead to improved conservation of bird communities.

Tree-shrub associations in grazed woodlands: First rodents, then cattle?

NARCIS (Netherlands)

Smit, C.; Verwijmeren, M.

2011-01-01

Spatial associations of tree saplings with spiny or toxic plants in grazed woodlands are generally explained by associational resistance, i. e., protection against grazing via a well-defended neighbor. In this study, we tested whether directed seed dispersal and post-dispersal seed removal by wood

Drivers of Productivity Trends in Cork Oak Woodlands over the Last 15 Years

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Maria João Santos

2016-06-01

Full Text Available Higher biodiversity leads to more productive ecosystems which, in turn, supports more biodiversity. Ongoing global changes affect ecosystem productivity and, therefore, are expected to affect productivity-biodiversity relationships. However, the magnitude of these relationships may be affected by baseline biodiversity and its lifeforms. Cork oak (Quercus suber woodlands are a highly biodiverse Mediterranean ecosystem managed for cork extraction; as a result of this management cork oak woodlands may have both tree and shrub canopies, just tree and just shrub canopies, and just grasslands. Trees, shrubs, and grasses may respond differently to climatic variables and their combination may, therefore, affect measurements of productivity and the resulting productivity-biodiversity relationships. Here, we asked whether the relationship between productivity and climate is affected by the responses of trees, shrubs, and grasses in cork oak woodlands in Southern Portugal. To answer this question, we linked a 15-year time series of Enhanced Vegetation Index (EVI derived from Landsat satellites to micrometeorological data to assess the relationship between trends in EVI and climate. Between 2000 and 2013 we observed an overall decrease in EVI. However, EVI increased over cork oaks and decreased over shrublands. EVI trends were strongly positively related to changes in relative humidity and negatively related to temperature. The intra-annual EVI cycle of grasslands and sparse cork oak woodland without understorey (savannah-like ecosystem had higher variation than the other land-cover types. These results suggest that oaks and shrubs have different responses to changes in water availability, which can be either related to oak physiology, to oaks being either more resilient or having lagged responses to changes in climate, or to the fact that shrublands start senesce earlier than oaks. Our results also suggest that in the future EVI could improve because the

Biotic survey of Los Alamos radioactive liquid-effluent receiving areas

International Nuclear Information System (INIS)

Miera, F.R. Jr.; Bostick, K.V.; Hakonson, T.E.; Nyhan, J.W.

A preliminary study was completed of the vegetation and small mammal communities and associated climatology in three canyon liquid waste receiving areas at the Los Alamos Scientific Laboratory. Data were gathered on plant and animal composition, distribution, and biomass, along with air temperature, humidity, and precipitation, as a function of elevation and where data were available with season. Initial studies of the understory vegetation in the spring of 1974 indicate grass species to be dominant at higher elevations, with forb species becoming dominant at lower elevations. Generally, the highest total mass estimates for standing green vegetation were obtained in the study sites located in the upper portions of the canyons where precipitation is greatest, and where the terrain and intermittent stream flow result in a wetter habitat. Fourteen species of small mammals were trapped or observed in canyon study areas during two trapping sessions of May--June 1974 and December 1974--February 1975. A greater number of species and the highest rodent biomass estimates in the spring were generally associated with the ponderosa pine/pinion--juniper woodland in the upper reaches of the canyons, and were lowest in the pinion--juniper woodland at the lower portions of the canyons. This trend was observed in only one of the canyons during the winter season. Climatological data gathered in the three canyons since 1973 are also presented to serve as a data base for future reference

Differences in overland flow, hydrophobicity and soil moisture dynamics between Mediterranean woodland types in a peri-urban catchment in Portugal

Science.gov (United States)

Ferreira, C. S. S.; Walsh, R. P. D.; Shakesby, R. A.; Keizer, J. J.; Soares, D.; González-Pelayo, O.; Coelho, C. O. A.; Ferreira, A. J. D.

2016-02-01

Forest hydrology has been widely investigated, but the impacts of different woodland types on hydrological processes within a peri-urban catchment mosaic are poorly understood. This paper investigates overland flow generation processes in three different types of woodland in a small (6.2 km2) catchment in central Portugal that has undergone strong urban development over the past 50 years. A semi-natural oak stand and a sparse eucalyptus stand on partly abandoned peri-urban land and a dense eucalyptus plantation were each instrumented with three 16 m2 runoff plots and 15 throughfall gauges, which were monitored at c. 1- to 2-week intervals over two hydrological years. In addition, surface soil moisture content (0-5 cm) and hydrophobicity (0-2 cm, 2-5 cm and 5-7 cm) were measured at the same time as overland flow and throughfall. Although all three woodland types produced relatively little overland flow (woodland types. This contrast in overland flow can be attributed to infiltration-excess processes operating in storms following dry antecedent weather when severe hydrophobicity was widespread in the dense eucalypt plantation, whereas it was of moderate and low severity and less widespread in the sparse eucalypt and oak woodlands, respectively. In contrast, under wet conditions greater (albeit still small) percentages of overland flow were produced in oak woodland than in the two eucalypt plantations; this was probably linked to saturation-excess overland flow being generated more readily at the oak site as a result of its shallower soil. Differences in water retention in surface depressions affected overland flow generation and downslope flow transport. Implications of the seasonal differentials in overland flow generation between the three distinct woodland types for the hydrological response of peri-urban catchments are addressed.

Allometric Models Based on Bayesian Frameworks Give Better Estimates of Aboveground Biomass in the Miombo Woodlands

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Shem Kuyah

2016-02-01

Full Text Available The miombo woodland is the most extensive dry forest in the world, with the potential to store substantial amounts of biomass carbon. Efforts to obtain accurate estimates of carbon stocks in the miombo woodlands are limited by a general lack of biomass estimation models (BEMs. This study aimed to evaluate the accuracy of most commonly employed allometric models for estimating aboveground biomass (AGB in miombo woodlands, and to develop new models that enable more accurate estimation of biomass in the miombo woodlands. A generalizable mixed-species allometric model was developed from 88 trees belonging to 33 species ranging in diameter at breast height (DBH from 5 to 105 cm using Bayesian estimation. A power law model with DBH alone performed better than both a polynomial model with DBH and the square of DBH, and models including height and crown area as additional variables along with DBH. The accuracy of estimates from published models varied across different sites and trees of different diameter classes, and was lower than estimates from our model. The model developed in this study can be used to establish conservative carbon stocks required to determine avoided emissions in performance-based payment schemes, for example in afforestation and reforestation activities.

Moth species richness, abundance and diversity in fragmented urban woodlands: implications for conservation and management strategies

OpenAIRE

Lintott, P.; Bunnefeld, N.; Fuentes-Montemayor, E.; Minderman, J.; Blackmore, L.; Goulson, D.; Park, K.

2014-01-01

Urban expansion threatens global biodiversity through the destruction of natural and semi-natural habitats and increased levels of disturbance. Whilst woodlands in urban areas may reduce the impact of urbanisation on biodiversity, they are often subject to under or over-management and consist of small, fragmented patches which may be isolated. Effective management strategies for urban woodland require an understanding of the\\ud ecology and habitat requirements of all relevant taxa. Yet, littl...

Competitive responses of seedlings and understory plants in longleaf pine woodlands: separating canopy influences above and below ground

Science.gov (United States)

Stephen D. Pecot; Robert J. Mitchell; Brian J. Palik; Barry Moser; J. Kevin Hiers

2007-01-01

A trenching study was used to investigate above- and below-ground competition in a longleaf pine (Pinus palustris P. Mill.) woodland. Trenched and nontrenched plots were replicated in the woodland matrix, at gap edges, and in gap centers representing a range of overstory stocking. One-half of each plot received a herbicide treatment to remove the...

Estimation of arboreal lichen biomass available to woodland caribou in Hudson Bay lowland black spruce sites

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Sarah K. Proceviat

2003-04-01

Full Text Available An arboreal lichen index to be utilized in assessing woodland caribou habitat throughout northeastern Ontario was developed. The "index" was comprised of 5 classes, which differentiated arboreal lichen biomass on black spruce trees, ranging from maximal quantities of arboreal lichen (class 5 to minimal amounts of arboreal lichen (class 1. This arboreal lichen index was subsequently used to estimate the biomass of arboreal lichen available to woodland caribou on lowland black spruce sites ranging in age from 1 year to 150 years post-harvest. A total of 39 sites were assessed and significant differences in arboreal lichen biomass were found, with a positive linear relationship between arboreal lichen biomass and forest age. It is proposed that the index be utilized by government and industry as a means of assessing the suitability of lowland black spruce habitat for woodland caribou in this region.

Woodland salamander responses to a shelterwood harvest-prescribed burn silvicultural treatment within Appalachian mixed-oak forests

Science.gov (United States)

Ford, W. Mark; Mahoney, Kathleen R.; Russell, Kevin R.; Rodrigue, Jane L.; Riddle, Jason D.; Schuler, Thomas M.; Adams, Mary Beth

2015-01-01

Forest management practices that mimic natural canopy disturbances, including prescribed fire and timber harvests, may reduce competition and facilitate establishment of favorable vegetative species within various ecosystems. Fire suppression in the central Appalachian region for almost a century has contributed to a transition from oak-dominated to more mesophytic, fire-intolerant forest communities. Prescribed fire coupled with timber removal is currently implemented to aid in oak regeneration and establishment but responses of woodland salamanders to this complex silvicultural system is poorly documented. The purpose of our research was to determine how woodland salamanders respond to shelterwood harvests following successive burns in a central Appalachian mixed-oak forest. Woodland salamanders were surveyed using coverboard arrays in May, July, and August–September 2011 and 2012. Surveys were conducted within fenced shelterwood-burn (prescribed fires, shelterwood harvest, and fencing to prevent white-tailed deer [Odocoileus virginianus] herbivory), shelterwood-burn (prescribed fires and shelterwood harvest), and control plots. Relative abundance was modeled in relation to habitat variables measured within treatments for mountain dusky salamanders (Desmognathus ochrophaeus), slimy salamanders (Plethodon glutinosus), and eastern red-backed salamanders (Plethodon cinereus). Mountain dusky salamander relative abundance was positively associated with canopy cover and there were significantly more individuals within controls than either shelterwood-burn or fenced shelterwood-burn treatments. Conversely, habitat variables associated with slimy salamanders and eastern red-backed salamanders did not differ among treatments. Salamander age-class structure within controls did not differ from shelterwood-burn or fenced shelterwood-burn treatments for any species. Overall, the woodland salamander assemblage remained relatively intact throughout the shelterwoodburn

Eastern wood-pewee (Contopus virens) breeding demography across a gradient of savanna, woodland, and forest in the Missouri Ozarks

Science.gov (United States)

Sarah W. Kendrick; Frank R. Thompson; Jennifer L. Reidy

2013-01-01

Better knowledge of bird response to savanna and woodland restoration is needed to inform management of these communities. We related temporal and habitat variables to breeding demography and densities of the Eastern Wood-Pewee (Contopus virens) across a gradient of savanna, woodland, and forest. We determined nest success, clutch size, young fledged...

An examination of recovery planning for forest-dwelling woodland caribou (Rangifer tarandus caribou in Ontario, Canada

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Christopher J. A. Wilkinson

2008-04-01

Full Text Available Ontario’s population of forest-dwelling woodland caribou is listed both federally and provincially as a species at risk. It is estimated that 20 000 woodland caribou remain in Ontario, of which approximately one quarter inhabit the boreal forest and are described as the sedentary forest-dwelling population. This paper examines the recovery strategy for this population developed by the Ministry of Natural Resources, as well as discussing the implications of provincial forestry policy on woodland caribou management. Commercial timber harvesting will likely soon be allowed in parts of the northern third of the province, in which woodland caribou habitat currently is relatively unimpaired by industrial development. Abstract in Norwegian / Sammendrag:Planlegging for bevaring av skogsøkotypen av Rangifer tarandus caribou i Ontario, CanadaSkogsvillreinen av skogsøkotypen i Ontario er vurdert som sårbar både føderalt og på provinsnivå. Av provinsens rundt 20 000 skogsvillrein hører omtrent en fjerdepart til den stasjonære skogsboende skogsøkoypen. Artikkelen ser på bevaringsstrategien som er utarbeidet av naturressursdepartementet i Ontario for denne spesielle bestanden og diskuterer konsekvensene for villreinen av provinsens skogpolitikk. Kommersiell hogst vil mest sannsynlig og snart bli tillatt i deler av Ontarios nordlige tredel der skogvillreinens leveområder er relativt upåvirket av industriell virksomhet.

Interactions between Canopy Structure and Herbaceous Biomass along Environmental Gradients in Moist Forest and Dry Miombo Woodland of Tanzania.

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Deo D Shirima

Full Text Available We have limited understanding of how tropical canopy foliage varies along environmental gradients, and how this may in turn affect forest processes and functions. Here, we analyse the relationships between canopy leaf area index (LAI and above ground herbaceous biomass (AGBH along environmental gradients in a moist forest and miombo woodland in Tanzania. We recorded canopy structure and herbaceous biomass in 100 permanent vegetation plots (20 m × 40 m, stratified by elevation. We quantified tree species richness, evenness, Shannon diversity and predominant height as measures of structural variability, and disturbance (tree stumps, soil nutrients and elevation as indicators of environmental variability. Moist forest and miombo woodland differed substantially with respect to nearly all variables tested. Both structural and environmental variables were found to affect LAI and AGBH, the latter being additionally dependent on LAI in moist forest but not in miombo, where other factors are limiting. Combining structural and environmental predictors yielded the most powerful models. In moist forest, they explained 76% and 25% of deviance in LAI and AGBH, respectively. In miombo woodland, they explained 82% and 45% of deviance in LAI and AGBH. In moist forest, LAI increased non-linearly with predominant height and linearly with tree richness, and decreased with soil nitrogen except under high disturbance. Miombo woodland LAI increased linearly with stem density, soil phosphorous and nitrogen, and decreased linearly with tree species evenness. AGBH in moist forest decreased with LAI at lower elevations whilst increasing slightly at higher elevations. AGBH in miombo woodland increased linearly with soil nitrogen and soil pH. Overall, moist forest plots had denser canopies and lower AGBH compared with miombo plots. Further field studies are encouraged, to disentangle the direct influence of LAI on AGBH from complex interrelationships between stand

Interactions between Canopy Structure and Herbaceous Biomass along Environmental Gradients in Moist Forest and Dry Miombo Woodland of Tanzania.

Science.gov (United States)

Shirima, Deo D; Pfeifer, Marion; Platts, Philip J; Totland, Ørjan; Moe, Stein R

2015-01-01

We have limited understanding of how tropical canopy foliage varies along environmental gradients, and how this may in turn affect forest processes and functions. Here, we analyse the relationships between canopy leaf area index (LAI) and above ground herbaceous biomass (AGBH) along environmental gradients in a moist forest and miombo woodland in Tanzania. We recorded canopy structure and herbaceous biomass in 100 permanent vegetation plots (20 m × 40 m), stratified by elevation. We quantified tree species richness, evenness, Shannon diversity and predominant height as measures of structural variability, and disturbance (tree stumps), soil nutrients and elevation as indicators of environmental variability. Moist forest and miombo woodland differed substantially with respect to nearly all variables tested. Both structural and environmental variables were found to affect LAI and AGBH, the latter being additionally dependent on LAI in moist forest but not in miombo, where other factors are limiting. Combining structural and environmental predictors yielded the most powerful models. In moist forest, they explained 76% and 25% of deviance in LAI and AGBH, respectively. In miombo woodland, they explained 82% and 45% of deviance in LAI and AGBH. In moist forest, LAI increased non-linearly with predominant height and linearly with tree richness, and decreased with soil nitrogen except under high disturbance. Miombo woodland LAI increased linearly with stem density, soil phosphorous and nitrogen, and decreased linearly with tree species evenness. AGBH in moist forest decreased with LAI at lower elevations whilst increasing slightly at higher elevations. AGBH in miombo woodland increased linearly with soil nitrogen and soil pH. Overall, moist forest plots had denser canopies and lower AGBH compared with miombo plots. Further field studies are encouraged, to disentangle the direct influence of LAI on AGBH from complex interrelationships between stand structure, environmental

Fuelwood and woodland improvement (or damage)

International Nuclear Information System (INIS)

Geisler, J.C.

1991-01-01

A 1985 survey (Green) of fuelwood use found that over one-fourth (26.4 percent) of Arkansas households burned fuelwood during the 1984-1985 heating season. More than 65 percent of the wood is self cut, and nearly one-half (47.7 percent) was cut from live timber. Removal of live timber through fuelwood cutting affords an opportunity to significantly improve hardwood or mixed hardwood-pine stands. It also provides an opportunity for extensive damage. This paper discusses the positive and negative impacts of fuelwood cutting and negative impacts of fuelwood cutting in live timber stands. It suggests programs for realizing woodland improvement through fuelwood cutting

Changing forest-woodland-savanna mosaics in Uganda: with implications for conservation

NARCIS (Netherlands)

Nangendo, G.

2005-01-01

Forest-Woodland-Savanna (FWS) mosaics are complex, highly varied and dynamic landscapes.Until recently, they were considered poor in terms of biodiversity. Consequently, only few scientific studies have been done on them and little attention has been paid to their

Inventories of fallout 21Pb and 137Cs radionuclides in moorland and woodland soils around Edinburgh urban area (UK)

International Nuclear Information System (INIS)

Likuku, A.S.; Branford, D.; Fowler, D.; Weston, K.J.

2006-01-01

Inventories of fallout 21 Pb and 137 Cs have been measured in moorland and woodland soils around the Edinburgh urban area, using a high purity germanium detector. The 21 Pb inventories in moorland soils were relatively uniform, with a mean value of 2520 ± 270 Bq m -2 . The mean 137 Cs inventory in moorland soils varied greatly from 1310 to 2100 Bq m -2 , with a mean value of 1580 ± 310 Bq m -2 . The variability was ascribed mainly to the non-uniform distribution of fallout Chernobyl 137 Cs. The mean 21 Pb and 137 Cs inventories in woodland canopy soils were found to be 3630 ± 380 Bq m -2 and 2510 ± 510 Bq m -2 , respectively. At sites for which both moorland and woodland data were available, the mean inventories provided fairly similar average enhancements of (47 ± 7)% and (46 ± 18)% of 21 Pb and 137 Cs under woodland canopy soils relative to open grassland soils, respectively. The enhancement factors are broadly in line with other independent findings in literature. Enhancement of both 21 Pb and 137 Cs in woodland soils relative to moorland soils is, in part, due to deposition by impaction during air turbulence, wash-off, gravitational settling and deposition during leaf senescence. Results of this study suggest that these processes affect both 21 Pb and 137 Cs carrier aerosols in a similar way

Income value of private amenities assessed in California oak woodlands

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Jose L. Oviedo

2012-07-01

Full Text Available Landowners in California were surveyed using a contingent valuation technique to assess its usefulness in estimating the monetary income value of private amenities from their oak woodland properties. Private amenities - such as recreation, scenic beauty and a rural lifestyle - are considered an important influence on rangeland owners, but few studies have attempted to place a monetary income value on them. Landowners were asked to estimate the maximum amount of earnings that they were willing to forgo before selling their property to invest in more commercially profitable, nonagrarian assets, and the proportion of the land price that they thought was explained by private amenities from their land. On average, landowners were willing to pay $54 per acre annually for private amenities, and they attributed 57% of the land price to them. Regression analysis revealed that the landowners' willingness to pay per acre decreased as property size increased. This approach sheds light on how landowners value the benefits of land owner-ship and offers insights for outreach and policy development for privately owned oak woodlands.

Reptile and amphibian responses to restoration of fire-maintained pine woodlands

Science.gov (United States)

Roger W Perry; D. Craig Rudolph; Ronald E. Thill

2009-01-01

Fire-maintained woodlands and savannas are important ecosystems for vertebrates in many regions of the world. These ecosystems are being restored by forest managers, but little information exists on herpetofaunal responses to this restoration in areas dominated by shortleaf pine (Pinus echinata). We compared habitat characteristics and...

Models for estimation of tree volume in the miombo woodlands of ...

African Journals Online (AJOL)

Volume of trees is an important parameter in forest management, but only volume models with limited geographical and tree size coverage have previously been developed for Tanzanian miombo woodlands. This study developed models for estimating total, merchantable stem and branches volume applicable for the entire ...

Carbon dioxide fluxes from a degraded woodland in West Africa and their responses to main environmental factors.

Science.gov (United States)

Ago, Expedit Evariste; Serça, Dominique; Agbossou, Euloge Kossi; Galle, Sylvie; Aubinet, Marc

2015-12-01

In West Africa, natural ecosystems such as woodlands are the main source for energy, building poles and livestock fodder. They probably behave like net carbon sinks, but there are only few studies focusing on their carbon exchange with the atmosphere. Here, we have analyzed CO 2 fluxes measured for 17 months by an eddy-covariance system over a degraded woodland in northern Benin. Specially, temporal evolution of the fluxes and their relationships with the main environmental factors were investigated between the seasons. This study shows a clear response of CO 2 absorption to photosynthetic photon flux density (Q p ), but it varies according to the seasons. After a significant and long dry period, the ecosystem respiration (R) has increased immediately to the first significant rains. No clear dependency of ecosystem respiration on temperature has been observed. The degraded woodlands are probably the "carbon neutral" at the annual scale. The net ecosystem exchange (NEE) was negative during wet season and positive during dry season, and its annual accumulation was equal to +29 ± 16 g C m -2 . The ecosystem appears to be more efficient in the morning and during the wet season than in the afternoon and during the dry season. This study shows diurnal and seasonal contrasted variations in the CO 2 fluxes in relation to the alternation between dry and wet seasons. The Nangatchori site is close to the equilibrium state according to its carbon exchanges with the atmosphere. The length of the observation period was too short to justify the hypothesis about the "carbon neutrality" of the degraded woodlands at the annual scale in West Africa. Besides, the annual net ecosystem exchange depends on the intensity of disturbances due to the site management system. Further research works are needed to define a woodland management policy that might keep these ecosystems as carbon sinks.

Recent land cover and use changes in Miombo woodlands of ...

African Journals Online (AJOL)

Forest and wood land ecosystems in Tanzania occupy more than 45% of the land area, more than two thirds of which made up of the Miombo woodland. The main form of land use in the Miombo region has long been shifting and small-scale sedentary cultivation. The lack of infrastructure and prevalence of deadly diseases ...

Cryptic indirect effects of exurban edges on a woodland community

Science.gov (United States)

R. J. Warren; S. M. Pearson; S. Henry; K. Rossouw; J. P. Love; M. J. Olejniczak; Katherine Elliott; M. A. Bradford

2015-01-01

Exurban development (e.g., second homes) in woodlands spreads urban land use impacts beyond suburbs, but because exurban developments often retain many components of original ecosystem structure—such as a forest canopy rather than open lawn—their ecological impacts may be underestimated. Changes in seed-dispersing ant behavior prompted by exurban land use,...

Characteristics of urban woodlands affecting breeding bird diversity and abundance

Science.gov (United States)

N.G. Tilghman

1987-01-01

Breeding bird communities were studied in 32 forest islands surrounded by urban development. These isolated woodlands in Springfield, Massachusetts, provided breeding habitats for a wider variety of birds (77 species) than previously described for other urban habitats (e.g. four times as many species as found in urban residential areas in the same city in a...

The Charcoal Trap: Miombo woodlands versus the energy needs of people

Science.gov (United States)

Merbold, Lutz; Maurice, Muchinda; Mukufute M, Mukelabai; J, Scholes Robert; Waldemar, Ziegler; L, Kutsch Werner

2010-05-01

Miombo woodlands cover the transition zone between the dry open savannas and the moist forests in Southern Africa and occupy the vast area of 2.7 Mio km2. These ecosystems are highly disturbed by deforestation, mostly for charcoal production. Charcoal has become the largest source to satisfy urban energy demands. Even though when charcoal is a less energy-efficient fuel compared to firewood but by having higher energy densities and thus being cheaper to transport. Over the last decades, charcoal production has become a full-time employment for migrant workers, resulting in very different and no longer sustainable deforestation patterns. Strategies to reduce the pressure on the miombo woodlands have to take aspects of employment and energy demand into account. The objectives of the study were to examine above- and belowground carbon losses from an intact miombo woodland (protected forest reserve) in comparison to a highly disturbed surrounding area due to charcoal production. Detection of changes in carbon concentrations and stocks were made possible by applying biomass- and soil inventories as well as the eddy-covariance method. These local results were up-scaled to countrywide estimates of carbon lost to the atmosphere by deforestation in addition to carbon losses fossil fuel combustion. The results show, that in the worst case scenario which does not assume any regeneration, a developing country as Zambia, can easily emit as much carbon per capita as a developed Western world country such as France, when deforestation is included in the national inventory (up to 9.1 t of CO2 per capita). However, regeneration is very probably when post-harvest disturbance is low. Further studies on miombo regeneration are highly demanded.

Oak woodland restoration in the Missouri Ozarks: two case studies examining responses of ground flora vegetation to prescribed fire

Science.gov (United States)

Aaron P. Stevenson

2016-01-01

Prescribed fire and thinning are two primary tools for restoring overgrown oak and oak-pine woodlands in Missouri. We wanted to examine woodland restoration efforts and determine if we were meeting our goals of promoting herbaceous ground flora cover and richness. We examined herbaceous responses to fire at two restoration sites in the Missouri Ozarks. At the first...

Treponemal disease in the middle Archaic to early Woodland periods of the western Tennessee River Valley.

Science.gov (United States)

Smith, Maria Ostendorf

2006-10-01

The high frequency of late prehistoric New World treponemal disease is attributable to the demographic changes concomitant with the adoption of agriculture. However, these demographic changes in group mobility and site density episodically preceded intensive plant domestication, suggesting possible staggered temporal change in observed treponemal disease case frequency. Thirteen convincing and an additional two probable (N = 581) cases of treponemal disease were identified in an eight-site skeletal sample spanning the Middle (6,000-3,000 BCE) to Late (2,500-ca. 1,000 to 500 BCE) Archaic and Early Woodland (500 BCE-0 CE) periods from the western Tennessee River Valley. Treponemal disease cases are infrequent in both the Middle (3/115, 2.6%) and Late (2 to 4 cases, subsistence economy across the Archaic-Woodland temporal boundary in the western Tennessee River Valley remained, as elsewhere, based on intensive hunting and collecting, the demographic corollaries of treponemal disease would apparently not be met. However, the traditional horizon marker of the Woodland period is the adoption of pottery, an activity associated with sedentism.

The Adolescent Condition in Thomas Hardy's The Woodlanders.

Science.gov (United States)

Nunan, Rosanna

In The Woodlanders, Hardy examines the intersections between adolescence as scientific fact and adolescence as utilitarian economic construction. Hardy posits that the emergence of adolescence as a social category provides an opportunity for further, excessive control of young women in a patriarchal society when science is taken at its word, but, paradoxically, also opens up a space for a new kind of freedom and rebellion when the adolescent condition of nineteenth-century scientific theorists is seized for the very subversive qualities which the Victorians oppose.

Carbon stocks, greenhouse gas emissions and water balance of Sudanese savannah woodlands in relation to climate change

Energy Technology Data Exchange (ETDEWEB)

Alam, S. A.

2013-06-01

Understanding the carbon (C) sequestration potential of drylands requires knowledge of the stocks of C in soils and biomass and on the factors affecting them. The overall aim of the study was to determine and evaluate the variation in the C stocks and water balance of Acacia savannah woodlands across the dryland (arid and semi-arid) region (10-16 deg N; 21-36 deg E) of the former Sudan (now mainly in the Republic of the Sudan) and how they are related to climatic factors and may be affected by climate change. The role played by small but numerous brick making industries on woodland deforestation in the region and greenhouse gas production was also investigated. The study region is often referred to as the gum belt because it is the world's major source of gum Arabic, which is harvested from Acacia trees. The soils in the centre and west of the region are mainly Arenosols (sandy soils) and those in the eastern part are mainly Vertisols (clay soils). The soils are C poor and often in a degraded state. This dissertation consists of a summary section and four articles (Study I, II, III and IV). Study I focuses on fuelwood consumption by the brick making industries (BMIs) and associated deforestation and greenhouse gas (GHG) emissions. In Study II the C densities (g C m-2) of the woodland tree biomass and soil (1 m) for 39 map sheets covering the study region were determined from national forest inventory data and global soil databases and the dependence on mean annual precipitation (MAP) and mean annual temperature (MAT) determined. The water balance of savannah woodlands for the same 39 map sheets was modelled in Study III and the variation in water balance components across the region evaluated. The potential impacts of climate change on woodland biomass C density and water-use (actual evapotranspiration, AET) was analysed for eight of the map sheets in Study IV. Sudanese BMIs consume a considerable amount of fuelwood that mainly comes from unsustainably managed

How can prescribed burning and harvesting restore shortleaf pine-oak woodland at the landscape scale in central United States? Modeling joint effects of harvest and fire regimes

Science.gov (United States)

Wenchi Jin; Hong S. He; Stephen R. Shifley; Wen J. Wang; John M. Kabrick; Brian K. Davidson

2018-01-01

Historical fire regimes in the central United States maintained open-canopy shortleaf pine-oak woodlands on xeric sites. Following large-scale harvest and fire suppression, those woodlands grew denser with more continuous canopy cover, and they gained mesic species at the expense of shortleaf pine. There is high interest in restoring shortleaf pine-oak woodlands; most...

Argan woodlands in South Morocco as an area of conflict between degradation and sustainable land use

Science.gov (United States)

Kirchhoff, Mario; Kagermeier, Andreas; Ries, Johannes B.

2016-04-01

The Argan woodlands are endemic for South Morocco and prone to degradation through expanding and intensifying agriculture and overgrazing. Unvegetated areas extend further due to degradation of soil and vegetation. Here infiltration is less than on vegetated areas, while runoff and soil erosion increase. The sale of the highly valuable oil, gained from the seeds of the argan tree, can be seen as an economic alternative for the region and a chance of survival for the argan woodlands. With the introduction of women's cooperatives for the production and sale of the oil, the Gesellschaft für Technische Zusammenarbeit (GTZ, Association for Technical Cooperation) hoped to halt argan degradation from 1995 to 2002. The effects of this approach shall be studied in a proposed DFG-project. The erosion gradient between soils under canopy cover and intertree areas in varying stages of degradation will be at the center of the analysis. Insight into onsite and offsite degradation shall be gained through the measurement of runoff and erosion rates, which lead to rill and gully erosion downslope. Measurements of soil chemical and physical properties might also help indicate when an argan woodland can be classified as natural. Furthermore to be studied are the effects of the new found value of the Argan woodlands among the local population with focus on regional tourism and a possible reduction of grazing pressure. Sustainable soil management in combination with the needs of the local population is essential for a sustainable land use in the region.

Enantiomeric distribution of major chiral volatile organic compounds in juniper-flavored distillates.

Science.gov (United States)

Pažitná, Alexandra; Spánik, Ivan

2014-02-01

The enantiomeric ratios of chiral volatile organic compounds in juniper-flavored spirits produced by various processing technologies in different EU countries were determined by multidimensional GC using solid-phase microextraction and liquid-liquid extraction as a sample pretreatment procedure. In total, more than 260 compounds were detected in studied spirits from which linalool, α-terpineol, 4-terpineol, linalool oxides, α-pinene, and verbenone were selected for enantiomeric separation. The significant differences in enantiomeric ratio of linalool and cis-linalool oxide allowed us to distinguish between samples produced in Slovakia and the United Kingdom from those produced in Germany, Czech Republic, and Belgium. The pure enantiomer of trans-linalool oxide was found only in samples from Germany. It was shown that the enantiomeric ratio is independent of the sample treatment procedure, and only small differences up to 1% were observed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Beyond cool: adapting upland streams for climate change using riparian woodlands.

Science.gov (United States)

Thomas, Stephen M; Griffiths, Siân W; Ormerod, Steve J

2016-01-01

Managed adaptation could reduce the risks of climate change to the world's ecosystems, but there have been surprisingly few practical evaluations of the options available. For example, riparian woodland is advocated widely as shade to reduce warming in temperate streams, but few studies have considered collateral effects on species composition or ecosystem functions. Here, we use cross-sectional analyses at two scales (region and within streams) to investigate whether four types of riparian management, including those proposed to reduce potential climate change impacts, might also affect the composition, functional character, dynamics and energetic resourcing of macroinvertebrates in upland Welsh streams (UK). Riparian land use across the region had only small effects on invertebrate taxonomic composition, while stable isotope data showed how energetic resources assimilated by macroinvertebrates in all functional guilds were split roughly 50:50 between terrestrial and aquatic origins irrespective of riparian management. Nevertheless, streams draining the most extensive deciduous woodland had the greatest stocks of coarse particulate matter (CPOM) and greater numbers of 'shredding' detritivores. Stream-scale investigations showed that macroinvertebrate biomass in deciduous woodland streams was around twice that in moorland streams, and lowest of all in streams draining non-native conifers. The unexpected absence of contrasting terrestrial signals in the isotopic data implies that factors other than local land use affect the relative incorporation of allochthonous subsidies into riverine food webs. Nevertheless, our results reveal how planting deciduous riparian trees along temperate headwaters as an adaptation to climate change can modify macroinvertebrate function, increase biomass and potentially enhance resilience by increasing basal resources where cover is extensive (>60 m riparian width). We advocate greater urgency in efforts to understand the ecosystem

Glade/woodland restoration in the St. Francis Mountain Bird Conservation Area

Science.gov (United States)

David A. Hasenbeck

2007-01-01

The Missouri Department of Conservation (MDC), the Missouri Department of Natural Resources, the U.S. Forest Service, and American Bird Conservancy, share goals to restore and manage high quality glade, savanna, and woodland habitats within the Saint Francis Bird Conservation Area. The partnership endeavors to maintain and enhance an ecosystem with native glade and...

Burning in Banksia Woodlands: How Does the Fire-Free Period Influence Reptile Communities?

Science.gov (United States)

Valentine, Leonie E.; Reaveley, Alice; Johnson, Brent; Fisher, Rebecca; Wilson, Barbara A.

2012-01-01

Fire is an important management tool for both hazard reduction burning and maintenance of biodiversity. The impact of time since last fire on fauna is an important factor to understand as land managers often aim for prescribed burning regimes with specific fire-free intervals. However, our current understanding of the impact of time since last fire on fauna is largely unknown and likely dependent on vegetation type. We examined the responses of reptiles to fire age in banksia woodlands, and the interspersed melaleuca damplands among them, north of Perth, Western Australia, where the current prescribed burning regime is targeting a fire-free period of 8–12 years. The response of reptiles to fire was dependent on vegetation type. Reptiles were generally more abundant (e.g. Lerista elegans and Ctenophorus adelaidensis) and specious in banksia sites. Several species (e.g. Menetia greyii, Cryptoblepharus buchananii) preferred long unburnt melaleuca sites (>16 years since last fire, YSLF) compared to recently burnt sites (16 YSLF). The terrestrial dragon C. adelaidensis and the skink Morethia obscura displayed a strong response to fire in banksia woodlands only. Highest abundances of the dragon were detected in the recently burnt (35 YSLF) banksia woodlands, while the skink was more abundant in older sites. Habitats from a range of fire ages are required to support the reptiles we detected, especially the longer unburnt (>16 YSLF) melaleuca habitat. Current burning prescriptions are reducing the availability of these older habitats. PMID:22496806

Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands.

Science.gov (United States)

Egger, Gregory; Politti, Emilio; Lautsch, Erwin; Benjankar, Rohan; Gill, Karen M; Rood, Stewart B

2015-09-15

River valley floodplains are physically-dynamic environments where fluvial processes determine habitat gradients for riparian vegetation. These zones support trees and shrubs whose life stages are adapted to specific habitat types and consequently forest composition and successional stage reflect the underlying hydrogeomorphic processes and history. In this study we investigated woodland vegetation composition, successional stage and habitat properties, and compared these with physically-based indicators of hydraulic processes. We thus sought to develop a hydrogeomorphic model to evaluate riparian woodland condition based on the spatial mosaic of successional phases of the floodplain forest. The study investigated free-flowing and dam-impacted reaches of the Kootenai and Flathead Rivers, in Idaho and Montana, USA and British Columbia, Canada. The analyses revealed strong correspondence between vegetation assessments and metrics of fluvial processes indicating morphodynamics (erosion and shear stress), inundation and depth to groundwater. The results indicated that common successional stages generally occupied similar hydraulic environments along the different river segments. Comparison of the spatial patterns between the free-flowing and regulated reaches revealed greater deviation from the natural condition for the braided channel segment than for the meandering segment. This demonstrates the utility of the hydrogeomorphic approach and suggests that riparian woodlands along braided channels could have lower resilience than those along meandering channels and might be more vulnerable to influences such as from river damming or climate change. Copyright © 2015 Elsevier Ltd. All rights reserved.

Burning in banksia woodlands: how does the fire-free period influence reptile communities?

Directory of Open Access Journals (Sweden)

Leonie E Valentine

Full Text Available Fire is an important management tool for both hazard reduction burning and maintenance of biodiversity. The impact of time since last fire on fauna is an important factor to understand as land managers often aim for prescribed burning regimes with specific fire-free intervals. However, our current understanding of the impact of time since last fire on fauna is largely unknown and likely dependent on vegetation type. We examined the responses of reptiles to fire age in banksia woodlands, and the interspersed melaleuca damplands among them, north of Perth, Western Australia, where the current prescribed burning regime is targeting a fire-free period of 8-12 years. The response of reptiles to fire was dependent on vegetation type. Reptiles were generally more abundant (e.g. Lerista elegans and Ctenophorus adelaidensis and specious in banksia sites. Several species (e.g. Menetia greyii, Cryptoblepharus buchananii preferred long unburnt melaleuca sites (>16 years since last fire, YSLF compared to recently burnt sites (16 YSLF. The terrestrial dragon C. adelaidensis and the skink Morethia obscura displayed a strong response to fire in banksia woodlands only. Highest abundances of the dragon were detected in the recently burnt (35 YSLF banksia woodlands, while the skink was more abundant in older sites. Habitats from a range of fire ages are required to support the reptiles we detected, especially the longer unburnt (>16 YSLF melaleuca habitat. Current burning prescriptions are reducing the availability of these older habitats.

The Woodlands: Una forma diferente de gobernar

Directory of Open Access Journals (Sweden)

Raquel Insa-Ciriza

2010-06-01

Full Text Available The Woodlands (Texas es uno de los mejores ejemplos de éxito de los partenariados público-privados entre el Departamento de Urbanismo y Vivienda Americano (Department of Housing and Urban Development, US - HUD y la empresa privada. The Woodlands, que fue creada como una «Nueva Ciudad» por la compañía Mitchell Energy & Development Corporation, ha ido creciendo y creando una masa crítica de residentes, trabajadores, su propio sentido de comunidad y lo más importante, su propia forma de gobierno. Es el único caso en Estados Unidos de ciudad gobernada por asociaciones privadas. Estas asociaciones, representadas por un Consejo de Administración, proveen la mayoría de los servicios públicos a los ciudadanos. En este artículo se muestra lo que llamo «complicidad ciudadana» basada en lo que el Nuevo Servicio Público define como gobierno basado en la comunidad. Ellos no están reinventando ninguna clase de gobierno, lo que están haciendo es crear una nueva forma de gobierno en la que los ciudadanos prefieren tomar el mando que servir. El estudio del caso que muestro nos ayuda a entender cómo una mayor participación de los ciudadanos en las tareas de la administración local puede hacer disminuir visiblemente el poder del promotor en el desarrollo de una Nueva Ciudad. Esta complicidad ciudadana se traduce en términos de implicación de los miembros de la comunidad en el crecimiento y en el Gobierno de la ciudad

Phylogeographical analysis of mtDNA data indicates postglacial expansion from multiple glacial refugia in woodland caribou (Rangifer tarandus caribou.

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Cornelya F C Klütsch

Full Text Available Glacial refugia considerably shaped the phylogeographical structure of species and may influence intra-specific morphological, genetic, and adaptive differentiation. However, the impact of the Quaternary ice ages on the phylogeographical structure of North American temperate mammalian species is not well-studied. Here, we surveyed ~1600 individuals of the widely distributed woodland caribou (Rangifer tarandus caribou using mtDNA control region sequences to investigate if glacial refugia contributed to the phylogeographical structure in this subspecies. Phylogenetic tree reconstruction, a median-joining network, and mismatch distributions supported postglacial expansions of woodland caribou from three glacial refugia dating back to 13544-22005 years. These three lineages consisted almost exclusively of woodland caribou mtDNA haplotypes, indicating that phylogeographical structure was mainly shaped by postglacial expansions. The putative centres of these lineages are geographically separated; indicating disconnected glacial refugia in the Rocky Mountains, east of the Mississippi, and the Appalachian Mountains. This is in congruence with the fossil record that caribou were distributed in these areas during the Pleistocene. Our results suggest that the last glacial maximum substantially shaped the phylogeographical structure of this large mammalian North American species that will be affected by climatic change. Therefore, the presented results will be essential for future conservation planning in woodland caribou.

Estimating forest and woodland aboveground biomass using active and passive remote sensing

Science.gov (United States)

Wu, Zhuoting; Dye, Dennis G.; Vogel, John M.; Middleton, Barry R.

2016-01-01

Aboveground biomass was estimated from active and passive remote sensing sources, including airborne lidar and Landsat-8 satellites, in an eastern Arizona (USA) study area comprised of forest and woodland ecosystems. Compared to field measurements, airborne lidar enabled direct estimation of individual tree height with a slope of 0.98 (R2 = 0.98). At the plot-level, lidar-derived height and intensity metrics provided the most robust estimate for aboveground biomass, producing dominant species-based aboveground models with errors ranging from 4 to 14Mg ha –1 across all woodland and forest species. Landsat-8 imagery produced dominant species-based aboveground biomass models with errors ranging from 10 to 28 Mg ha –1. Thus, airborne lidar allowed for estimates for fine-scale aboveground biomass mapping with low uncertainty, while Landsat-8 seems best suited for broader spatial scale products such as a national biomass essential climate variable (ECV) based on land cover types for the United States.

Radiocaesium - 137 in cultivated and woodland mushrooms

International Nuclear Information System (INIS)

Stankovic, S.; Stankovic, A.

1997-01-01

In the present work the results obtained for activity levels of 137 Cs in samples of cultivated mushrooms (Champignons - Agaricus Silvicola Vitt. Peck.) and woodland fruits ( Chantarelle - Cantarelus Cibarius Fr.; Bollets -Boletus Edulis. ex Fr. and Black Trumpets - Cratarelus Conucopioides) are presented. These samples were collected from 1991 to 1996. Biodiversity of the mushrooms regarding their uptake of radionuclides was found. Thus, the maximum value of 137 Cs activity was found in the sample of dry Bollets 375 Bq/kg in 1993. Moreover, the mean activity level of this species was much higher (126 + - 10 Bq/kg) in 1996. than, levels found in any samples taken from the same environment. (author)

Design, implementation, and analysis methods for the National Woodland Owner Survey

Science.gov (United States)

Brett J. Butler; Earl C. Leatherberry; Michael S. Williams; Michael S. Williams

2005-01-01

The National Woodland Owner Survey (NWOS) is conducted by the USDA Forest Service, Forest Inventory and Analysis program to increase our understanding of private forest-land owners in the United States. The information is intended to help policy makers, resource managers, and others interested in the forest resources of the United States better understand the social...

Inventories of fallout {sup 21}Pb and {sup 137}Cs radionuclides in moorland and woodland soils around Edinburgh urban area (UK)

Energy Technology Data Exchange (ETDEWEB)

Likuku, A.S. [School of Physics, University of Edinburgh, James Clerk Maxwell Building, King' s Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom)]. E-mail: alikuku@temo.bca.bw; Branford, D. [School of Physics, University of Edinburgh, James Clerk Maxwell Building, King' s Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom); Fowler, D. [Centre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Weston, K.J. [School of GeoSciences, University of Edinburgh, James Clerk Maxwell Building, King' s Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom)

2006-07-01

Inventories of fallout {sup 21}Pb and {sup 137}Cs have been measured in moorland and woodland soils around the Edinburgh urban area, using a high purity germanium detector. The {sup 21}Pb inventories in moorland soils were relatively uniform, with a mean value of 2520 {+-} 270 Bq m{sup -2}. The mean {sup 137}Cs inventory in moorland soils varied greatly from 1310 to 2100 Bq m{sup -2}, with a mean value of 1580 {+-} 310 Bq m{sup -2}. The variability was ascribed mainly to the non-uniform distribution of fallout Chernobyl {sup 137}Cs. The mean {sup 21}Pb and {sup 137}Cs inventories in woodland canopy soils were found to be 3630 {+-} 380 Bq m{sup -2} and 2510 {+-} 510 Bq m{sup -2}, respectively. At sites for which both moorland and woodland data were available, the mean inventories provided fairly similar average enhancements of (47 {+-} 7)% and (46 {+-} 18)% of {sup 21}Pb and {sup 137}Cs under woodland canopy soils relative to open grassland soils, respectively. The enhancement factors are broadly in line with other independent findings in literature. Enhancement of both {sup 21}Pb and {sup 137}Cs in woodland soils relative to moorland soils is, in part, due to deposition by impaction during air turbulence, wash-off, gravitational settling and deposition during leaf senescence. Results of this study suggest that these processes affect both {sup 21}Pb and {sup 137}Cs carrier aerosols in a similar way.

Mapping Decadal Land Cover Changes in the Woodlands of North Eastern Namibia from 1975 to 2014 Using the Landsat Satellite Archived Data

Directory of Open Access Journals (Sweden)

Vladimir R. Wingate

2016-08-01

Full Text Available Woodlands and savannahs provide essential ecosystem functions and services to communities. On the African continent, they are widely utilized and converted to subsistence and intensive agriculture or urbanized. This study investigates changes in land cover over four administrative regions of North Eastern Namibia within the Kalahari woodland savannah biome, covering a total of 107,994 km2. Land cover is mapped using multi-sensor Landsat imagery at decadal intervals from 1975 to 2014, with a post-classification change detection method. The dominant change observed was a reduction in the area of woodland savannah due to the expansion of agriculture, primarily in the form of small-scale cereal and pastoral production. More specifically, woodland savannah area decreased from 90% of the study area in 1975 to 83% in 2004, and then increased to 86% in 2014, while agricultural land increased from 6% to 12% between 1975 and 2014. We assess land cover changes in relation to towns, villages, rivers and roads and find most changes occurred in proximity to these. In addition, we find that most land cover changes occur within land designated as communally held, followed by state protected land. With widespread changes occurring across the African continent, this study provides important data for understanding drivers of change in the region and their impacts on the distribution of woodland savannahs.

Annual and monthly range fidelity of female boreal woodland caribou in respons to petroleum development

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Boyan V. Tracz

2010-03-01

Full Text Available Petroleum-sector development in northern Alberta, Canada has been implicated as one factor influencing the decline of boreal woodland caribou (Rangifer tarandus caribou. Previous research showed that caribou are farther from petroleum-sector disturbances within their home range than expected. As petroleum development increases, the distance caribou can selectively place themselves relative to industrial disturbance must decrease, because distances between disturbances decrease. Conceptually, the number of local disturbances becomes so large that caribou either abandon their local avoidance behaviour or leave their traditional home range. We evaluated whether an intense petroleum- development event in northern Alberta was sufficient to result in home range abandonment by female woodland caribou. Using well locations as an index of petroleum development, we found that caribou studied from 1992 to 2000 did not change their annual or monthly range fidelity as a function of development intensity. Caribou remained in peatland complexes containing a large number of petroleum-sector disturbances rather than move to new areas, presumably because the risks of dispersing across upland habitat to reach other suitable habitat are high. Such range fidelity may have fitness consequences for woodland caribou if they suffer greater predation in areas where petroleum development is occurring.

Proceedings of a symposium on oak woodlands: ecology, management, and urban interface issues; 19–22 March 1996; San Luis Obispo, CA

Science.gov (United States)

Norman H. Pillsbury; Jared Verner; William D. Tietje

1997-01-01

Oak woodlands, the predominant vegetation type in the most inhabitable areas of California, comprise 10 million acres in the State and have been used primarily for livestock production. Today, residential intrusion into oak woodlands results in habitat fragmentation and degradation of economic, esthetic, and ecological values. Decision makers must face up to the...

Natural woodland vegetation and plant species richness of the urban open spaces in Gauteng, South Africa

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C.H. Grobler

2002-01-01

Full Text Available It is estimated that approximately 60 % of the world’s population will be living in urban areas by 2025. In Gauteng, the most densely populated province in South Africa, the natural open spaces are continually under threat from development. Vegetation is the most physical representation of the environment on which all animals are ultimately dependent. In order to evaluate an areas potential for development or conservation it is necessary to make a thorough inventory of the plant communities and their associated habitats. A survey of the natural woodlands was undertaken as part of a project describing the vegetation of the natural open spaces within the Gauteng region. Relevés were compiled in 73 stratified random sample plots in selected open spaces within the study area. A TWINSPAN classification, refined by Braun-Blanquet procedures, indicated six woodland communities that can be grouped into two major woodland communities. A classification and description of these communities as well as their species richness are presented. The results indicate that there are still patches of well-preserved natural vegetation within the study area and contribute to the limited knowledge that presently exists for the vegetation of the area.

Impacts of communal fuelwood extraction on lidar-estimated biomass patterns of savanna woodlands

CSIR Research Space (South Africa)

Wessels, Konrad J

2012-07-01

Full Text Available Approximately 54% of rural households in South Africa continue to use wood as their main source of energy, mainly for cooking and heating. The provision of biomass by savanna woodlands is thus of considerable value to rural households and therefore...

Effects of breeding habitat (woodland versus urban) and metal pollution on the egg characteristics of great tits (Parus major).

Science.gov (United States)

Hargitai, Rita; Nagy, Gergely; Nyiri, Zoltán; Bervoets, Lieven; Eke, Zsuzsanna; Eens, Marcel; Török, János

2016-02-15

In an urban environment, birds are exposed to metals, which may accumulate in their tissues and cause oxidative stress. Female birds may eliminate these pollutants through depositing them into eggs, thus eggs become suitable bioindicators of pollution. In this study, we aimed to analyse whether eggshell spotting pattern, egg volume, eggshell thickness and egg yolk antioxidant (lutein, tocopherol, retinol and selenium) levels were related to the breeding area (woodland versus urban) and the metal levels in the eggshell of a small passerine species, the great tit (Parus major). In the urban habitat, soil and eggshells contained higher concentrations of metals, and soil calcium level was also higher than that in the woodland. Eggshell spotting intensity and egg volume did not differ between eggs laid in the woodland and the urban park, and these traits were not related to the metal levels of the eggshell, suggesting that these egg characteristics are not sensitive indicators of metal pollution. A more aggregated eggshell spotting distribution indicated a higher Cu concentration of the eggshell. We found that eggshells were thinner in the less polluted woodland habitat, which is likely due to the limited Ca availability of the woodland area. Great tit eggs laid in the urban environment had lower yolk lutein, retinol and selenium concentrations, however, as a possible compensation for these lower antioxidant levels, urban females deposited more tocopherol into the egg yolk. It appears that females from different breeding habitats may provide similar antioxidant protection for their offspring against oxidative damage by depositing different specific dietary antioxidants. Egg yolk lutein and retinol levels showed a negative relationship with lead concentration of the eggshell, which may suggest that lead had a negative impact on the amount of antioxidants available for embryos during development in great tits. Copyright © 2015 Elsevier B.V. All rights reserved.

Landowner total income from oak woodland working landscapes in Spain and California

Science.gov (United States)

Jose L. Oviedo; Lynn Huntsinger; Pablo Campos

2015-01-01

Conventional accounting of agricultural income focuses on the commercial operating income from oak woodland ranches, omitting the value of amenities to the landowner and real capital gains, which includes land revaluation (appreciation). These accounting exercises also mix income earned through self-employed (landowner and household) labor with ranch operating income,...

75 FR 49524 - Woodland Mills Corporation, Mill Spring, NC; Notice of Affirmative Determination Regarding...

Science.gov (United States)

2010-08-13

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-73,695] Woodland Mills Corporation, Mill Spring, NC; Notice of Affirmative Determination Regarding Application for Reconsideration By application dated July 22, 2010, petitioners requested administrative [[Page 49525

Management effect on bird and arthropod interaction in suburban woodlands

Science.gov (United States)

2011-01-01

Background Experiments from a range of ecosystems have shown that insectivorous birds are important in controlling the populations of their invertebrate prey. Here, we report on a large field experiment testing the hypothesis that management for enhancing recreational values in suburban woodlands affects the intensity of bird predation on canopy-living arthropods. Bird exclosures were used in two types of management (understory clearance and dense understory) at two foraging heights in oak Quercus robur canopies and the experiment was replicated at two sites. Results The biomass and abundance of arthropods were high on net-enclosed branches but strongly reduced on control branches in both types of management. In woods with dense understory, the effect of bird predation on arthropod abundance was about twice as high as in woods with understory clearance. The effect of bird predation on arthropod biomass was not significantly affected by management. Conclusions Our data provide experimental evidence to support the idea that bird predation on arthropods can be affected by forest management. We suggest that the mechanism is twofold: reduction of bird abundance and shift of foraging behaviour. In urban woodlands, there may be a management trade-off between enhancing recreational values and promoting bird predation rates on arthropods. PMID:21362174

Leaf gas exchange in the frankincense tree (Boswellia papyrifera) of African dry woodlands

NARCIS (Netherlands)

Mengistu, T.; Sterck, F.J.; Fetene, M.; Tadesse, W.; Bongers, F.

2011-01-01

A conceptual model was tested for explaining environmental and physiological effects on leaf gas exchange in the deciduous dry tropical woodland tree Boswellia papyrifera (Del.) Hochst. For this species we aimed at (i) understanding diurnal patterns in leaf gas exchange, (ii) exploring cause–effect

Differential responses to woodland character and landscape context by cryptic bats in urban environments.

Directory of Open Access Journals (Sweden)

Paul R Lintott

Full Text Available Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes.

Differential responses to woodland character and landscape context by cryptic bats in urban environments.

Science.gov (United States)

Lintott, Paul R; Bunnefeld, Nils; Minderman, Jeroen; Fuentes-Montemayor, Elisa; Mayhew, Rebekah J; Olley, Lena; Park, Kirsty J

2015-01-01

Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes.

Fragmented habitats of traditional fruit orchards are important for dead wood-dependent beetles associated with open canopy deciduous woodlands.

Science.gov (United States)

Horak, Jakub

2014-06-01

The conservation of traditional fruit orchards might be considered to be a fashion, and many people might find it difficult to accept that these artificial habitats can be significant for overall biodiversity. The main aim of this study was to identify possible roles of traditional fruit orchards for dead wood-dependent (saproxylic) beetles. The study was performed in the Central European landscape in the Czech Republic, which was historically covered by lowland sparse deciduous woodlands. Window traps were used to catch saproxylic beetles in 25 traditional fruit orchards. The species richness, as one of the best indicators of biodiversity, was positively driven by very high canopy openness and the rising proportion of deciduous woodlands in the matrix of the surrounding landscape. Due to the disappearance of natural and semi-natural habitats (i.e., sparse deciduous woodlands) of saproxylic beetles, orchards might complement the functions of suitable habitat fragments as the last biotic islands in the matrix of the cultural Central European landscape.

Quantifying the impacts of piñon mortality on ecosystem-scale carbon and water cycling: a twinned flux tower approach

Science.gov (United States)

Fox, A. M.; Litvak, M. E.; McDowell, N.; Rahn, T.; Ryan, M. G.

2010-12-01

Piñon-juniper (PJ) woodlands, which occupy 24 million ha throughout the Southwest, proved to be extremely vulnerable to an extended drought that began in 1999, leading to an abrupt die-off of 40 to 95% of piñon pine (Pinus edulis) and 2-25% of juniper (Juniperus monosperma) in less than 3 years. Climate predictions for the region suggest such droughts are likely to become more frequent and widespread in the future, extending northwards. Such large-scale change in vegetation has the potential to trigger rapid changes in ecosystem carbon dynamics and the local and regional hydrologic cycle. We are using a twinned ecosystem-scale manipulation study to quantify the transient dynamics of carbon and water flux responses to piñon mortality. A combination of eddy covariance, soil respiration and moisture, sap flow and biomass carbon pool measurements are being made at an undisturbed PJ woodland (control) site and at a manipulation site within 2 miles of the control where all piñon trees greater than 7 cm diameter at breast height within the 4 ha flux footprint were killed in September 2009 using girdling and herbicide injection following 6 months of background measurements. We hypothesis that piñon mortality alters the local scale carbon cycle by shifting a large stock of carbon from productive biomass to detritus, leading to an initial decrease in net primary production and an increase in ecosystem respiration and net carbon flux to the atmosphere. However, reduced competition for water in these water-limited ecosystems and increased light availability may lead to compensatory growth in surviving small piñon, juniper and understory vegetation, offsetting or exceeding the expected reduction in NPP from piñon mortality. Because litter and coarse woody debris are slow to decompose in semiarid environments we hypothesize that the manipulation site will continue to be net carbon sources even after NPP recovers. Our general hypothesis for the local scale water cycle is

The influence of canopy strata on remotely sensed observations of savanna-woodlands

International Nuclear Information System (INIS)

Fuller, D.O.; Prince, S.D.; Astle, W.L.

1997-01-01

Upwelling radiance from savanna woodlands may originate from two separate layers: (1) the field layer, which is a mixture of soil, litter and herbs, and (2) the tree layer composed of woody parts and leaves. Unless detailed field data are available for a particular savanna location, it is unknown how the individual layers may influence the red and near-infrared signals and whether radiative interactions between layers are important. We employed an existing radiative transfer model (SAIL) in conjunction with a simple, single-scattering model to analyse the variation in Advanced Very High Resolution Radiometer (AVHRR) channel 1 and 2 response as well as NDVI for savanna-woodland vegetation in eastern Zambia. Linear fits between predicted and observed values of reflectance and NDVI were significant ( p 0.05) in the red and in NDVI, however, the model failed to explain a high proportion of the variation in near-infrared. Red and NDVI in sites where tree cover was high were also poorly modelled, which suggests that multiple interactions between canopy layers make a single-scattering model unreliable, particularly in the near-infrared. Modelled results were also compared to aircraft radiometer measurements provided by the integrated camera and radiometer instrument (ICAR). Simulations parameterized with field data suggest that the model may be used to infer tree and field layer influences at different points during the seasonal cycle. Results also suggest that the field layer dominated the signal in our savanna woodland sites throughout most points of the seasonal cycle, which is consistent with other canopy radiative-transfer studies. Simulations indicated that the tree layer was a relatively more important component of NDVI during the dry season when the field layer was largely senescent, accounting for 20-40 per cent of the satellite signal. (author)

Transpiration of Eucalyptus woodlands across a natural gradient of depth-to-groundwater.

Science.gov (United States)

Zolfaghar, Sepideh; Villalobos-Vega, Randol; Zeppel, Melanie; Cleverly, James; Rumman, Rizwana; Hingee, Matthew; Boulain, Nicolas; Li, Zheng; Eamus, Derek

2017-07-01

Water resources and their management present social, economic and environmental challenges, with demand for human consumptive, industrial and environmental uses increasing globally. However, environmental water requirements, that is, the allocation of water to the maintenance of ecosystem health, are often neglected or poorly quantified. Further, transpiration by trees is commonly a major determinant of the hydrological balance of woodlands but recognition of the role of groundwater in hydrological balances of woodlands remains inadequate, particularly in mesic climates. In this study, we measured rates of tree water-use and sapwood 13C isotopic ratio in a mesic, temperate Eucalypt woodland along a naturally occurring gradient of depth-to-groundwater (DGW), to examine daily, seasonal and annual patterns of transpiration. We found that: (i) the maximum rate of stand transpiration was observed at the second shallowest site (4.3 m) rather than the shallowest (2.4 m); (ii) as DGW increased from 4.3 to 37.5 m, stand transpiration declined; (iii) the smallest rate of stand transpiration was observed at the deepest (37.5 m) site; (iv) intrinsic water-use efficiency was smallest at the two intermediate DGW sites as reflected in the Δ13C of the most recently formed sapwood and largest at the deepest and shallowest DGW sites, reflecting the imposition of flooding at the shallowest site and the inaccessibility of groundwater at the deepest site; and (v) there was no evidence of convergence in rates of water-use for co-occurring species at any site. We conclude that even in mesic environments groundwater can be utilized by trees. We further conclude that these forests are facultatively groundwater-dependent when groundwater depth is transpiration is likely to increase significantly at the three shallowest DGW sites. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Wildlife diversity of restored shortleaf pine-oak woodlands in the northern Ozarks

Science.gov (United States)

Corinne S. Mann; Andrew R. Forbes

2007-01-01

Historic changes in land use have altered the plant composition and structure of shortleaf pine-oak woodlands in the northern Ozarks. As a result, the composition of wildlife communities in these landscapes has shifted to species that are more associated with closed canopy oak forests. For example, the red-cockaded woodpecker (Picoides borealis) has...

Changes to oak woodland stand structure and ground flora composition caused by thinning and burning

Science.gov (United States)

Kinkead, Carter O.; Kabrick, John M.; Stambaugh, Michael C.; Grabner, Keith W.

2013-01-01

Our objective was to quantify the cumulative effects of prescribed burning and thinning on forest stocking and species composition at a woodland restoration experiment site in the Ozark Highlands of Missouri. Our study used four treatments (burn, harvest, harvest and burn, control) on three slope position and aspect combinations (south, north, ridge) replicated in three complete blocks. Harvested stands were thinned from below to 40 percent residual stocking. Two prescribed fires were applied to both burn and harvest-burn treatment units in a 5-year period. Results reflect changes that have taken place over a 6-year period, from pretreatment conditions to 1 year after the last fire. In this period, there was a 10-percent reduction in the stocking in burned stands compared to control and a 6-percent reduction in harvested and burned stands compared to harvested stands. Compared to the control, percentage ground cover of woodland indicators was seven times greater in burned stands, six times greater in harvested stands, and 22 percent greater in harvested and burned stands. Th ere was no significant (P > 0.05) interaction between aspect and treatment on stocking or ground flora cover. Th is study indicated that silvicultural treatments do achieve various goals that are common to managers who aim to restore woodland communities.

Land Cover Change in Northern Botswana: The Influence of Climate, Fire, and Elephants on Semi-Arid Savanna Woodlands

Directory of Open Access Journals (Sweden)

John Tyler Fox

2017-10-01

Full Text Available Complex couplings and feedback among climate, fire, and herbivory drive short- and long-term patterns of land cover change (LCC in savanna ecosystems. However, understanding of spatial and temporal LCC patterns in these environments is limited, particularly for semi-arid regions transitional between arid and more mesic climates. Here, we use post-classification analysis of Landsat TM (1990, ETM+ (2003, and OLI (2013 satellite imagery to classify and assess net and gross LCC for the Chobe District, a 21,000 km2 area encompassing urban, peri-urban, rural, communally-managed (Chobe Enclave, and protected land (Chobe National Park, CNP, and six protected forest reserves. We then evaluate spatiotemporal patterns of LCC in relation to precipitation, fire detections (MCD14M, 2001–2013 from the Moderate Resolution Imaging Spectroradiometer (MODIS, and dry season elephant (Loxodonta africana aerial survey data (2003, 2006, 2012, 2013. Woodland cover declined over the study period by 1514 km2 (16.2% of initial class total, accompanied by expansion of shrubland (1305 km2, 15.7% and grassland (265 km2, 20.3%. Net LCC differed importantly in protected areas, with higher woodland losses observed in forest reserves compared to the CNP. Loss of woodland was also higher in communally-managed land for the study period, despite gains from 2003–2013. Gross (class changes were characterized by extensive exchange between woodland and shrubland during both time steps, and a large expansion of shrubland into grassland and bare ground from 2003–2013. MODIS active fire detections were highly variable from year to year and among the different protected areas, ranging from 1.8 fires*year−1/km2 in the Chobe Forest Reserve to 7.1 fires*year−1/km2 in the Kasane Forest Reserve Extension. Clustering and timing of dry season fires suggests that ignitions were predominately from anthropogenic sources. Annual fire count was significantly related to total annual rainfall

Unleached Prosopis litter inhibits germination but leached stimulates seedling growth of dry woodland species

NARCIS (Netherlands)

Muturi, Gabriel M.; Poorter, Lourens; Bala, Pauline; Mohren, Godefridus M.J.

2017-01-01

Prosopis chilensis-Prosopis juliflora hybrid (hereinafter referred to as Prosopis species) invade riverine Acacia woodlands and replace indigenous Acacia tortilis through mechanism that are not yet well understood. Therefore, we tested the hypothesis that dense shade and allelopathic effects of

Moccasins into Slippers: Woodlands Indian Hats, Bags, and Shoes in Tradition and Transformation.

Science.gov (United States)

Phillips, Ruth B.

1990-01-01

In the mid-nineteenth century, an abrupt transformation occurred in textiles and other art forms of northeastern Woodlands Indians. Trade, tourism, and survival needs sparked changes in materials used and garment types produced, as well as substitution of a new vocabulary of floral imagery for "pagan" iconographic traditions. (SV)

Monitoring Values and Practices of Oak Woodland Decision Makers on the Urban Fringe

Science.gov (United States)

William Stewart

1991-01-01

Concern over oak woodlands has shifted away from ranch management towards residential areas. This shift has been accompanied by the involvement of decision makers who previously had little involvement with rangeland policies and practices. A survey of three recent Cooperative Extension workshops illustrates a number of important patterns regarding interest and...

Stable carbon isotope analysis of soil organic matter illustrates vegetation change at the grassland/woodland boundary in southeastern Arizona, USA.

Science.gov (United States)

McPherson, G R; Boutton, T W; Midwood, A J

1993-02-01

In southeastern Arizona, Prosopis juliflora (Swartz) DC. and Quercus emoryi Torr. are the dominant woody species at grassland/woodland boundaries. The stability of the grassland/woodland boundary in this region has been questioned, although there is no direct evidence to confirm that woodland is encroaching into grassland or vice versa. We used stable carbon isotope analysis of soil organic matter to investigate the direction and magnitude of vegetation change along this ecotone. δ 13 C values of soil organic matter and roots along the ecotone indicated that both dominant woody species (C 3 ) are recent components of former grasslands (C 4 ), consistent with other reports of recent increases in woody plant abundance in grasslands and savannas throughout the world. Data on root biomass and soil organic matter suggest that this increase in woody plant abundance in grasslands and savannas may increase carbon storage in these ecosystems, with implications for the global carbon cycle.

ANALYSIS OF DWARF MISTLETOE ARCEUTHOBIUM OXYCEDRI (DC. M. BIEB. AND ITS PRINCIPAL HOST EASTERN PRICKLY JUNIPER JUNIPERUS DELTOIDES R. P. ADAMS DISTRIBUTION IN CRIMEA USING GIS TECHOLOGIES

Directory of Open Access Journals (Sweden)

O. V. Kukushkin

2017-03-01

Full Text Available The current study highlights the distribution pattern of juniper dwarf mistletoe (Arceuthobium oxycedri, a semi-parasite of the Eastern prickly juniper (Juniperus deltoides, in Crimea. A. oxycedri has considerably narrower range in Crimea as compared to its principal host and its ubiquitous distribution is rather sporadic. Nature observations characterize A. oxycedri as a thermophilic and mezo-хerophytic species confined to the low-mountain terrains with mild sub-Mediterranean climate. Significant sites of permanent infection have been discovered at the Crimean coast and in the warmest southwestern part of the Crimean Mountains to the south from the Belbek River valley. Greek juniper (J. excelsa is a codominant species growing side by side with J. deltoids in the majority of localities examined that have the high infection rate. Generally, J. excelsa is an insusceptible species in relation to the parasite; nevertheless, it is affected by A. oxycedri at several sites. Birds feeding habit to consume J. excelsa and J. deltoides fleshy berry-like cones helps to maintain the high infection rate and to disseminate mistletoe seeds at the distance of approximately 4 km. Modeling ecological niche and creating maps of potential range of the parasite and its principal host using MaxEnt 3.3.3k software have demonstrated that A. oxycedri distribution in Crimea at present may be wider than it has been currently observed. It is noteworthy that while modeling such bioclimatic indicators as the minimum winter temperatures and the elevation above sea level were irrelevant for establishing the distribution range of the parasite. Presumably the limited distribution of A. oxycedri can be attributed to the history of forming J. deltoides range in the late Pleistocene – Holocene, alongside with a low speed of the parasite dissemination from Quaternary refugia in the southernmost part of the Crimean Peninsula.

The importance of herbivore interactions for the dynamics of African savanna woodlands : an hypothesis

NARCIS (Netherlands)

Van de Koppel, J; Prins, HHT

Current hypotheses to explain dynamic transitions between savanna grasslands and woodlands in Africa focus on grazing by elephant or the influence of fire. Using a simple mathematical model, this paper argues that interactions between small herbivores such as impala or buffalo and large herbivores

Vegetation structure characteristics and relationships of Kalahari woodlands and savannas

CSIR Research Space (South Africa)

Privette, JL

2004-03-01

Full Text Available modeling has become widespread (e.g., Potter et al., 1993, 1998; Sellers et al., 1996). Nevertheless, knowledge of vegetation canopy struc- ture remains incomplete in many remote areas, such as sub-Saharan Africa. First, comparatively small changes... 929 460 Colophospermum mopane woodland with patches of Terminalia sericea thicket Harry Oppenheimer Okavango Research Centre; Measurements were 3km east of a permanent flux tower 23.591E Okwa River Crossing, Botswana 22.411S 1089 407 Open Kalahari...

Bird species associated with green ash woodlands in the Slim Buttes, South Dakota

Science.gov (United States)

Robert A. Hodorff; Carolyn Hull Sieg

1986-01-01

In western South Dakota, native deciduous woodlands are uncommon, constituting less than 1% of the total land area (Boldt et al. 1978). The Green Ash/Common Chokecherry (Fraxinus pennsylvanica/Prunus virginiana) habitat type is the major deciduous habitat type in northwestern South Dakota (Hansen and Hoffman 1985). This type occurs in depressions,...

Dogwood borer (Lepidoptera: Sesiidae) abundance and seasonal flight activity in apple orchards, urban landscapes, and woodlands in five eastern states.

Science.gov (United States)

Bergh, J C; Leskey, T C; Walgenbach, J F; Klingeman, W E; Kain, D P; Zhang, A

2009-06-01

The relative abundance and seasonal flight activity of dogwood borer, Synanthedon scitula Harris (Lepidoptera: Sesiidae), was measured using weekly records from traps baited with its sex pheromone and deployed in apple orchards, urban landscapes, and native woodland sites in New York, West Virginia, Virginia, North Carolina, and Tennessee in 2005 and 2006. The mean total number of moths captured per site in apple orchards was 3,146 +/- 644 and 3095 +/- 584 SE in 2005 and 2006, respectively, exceeding captures at urban sites by 16 and 13 times and at woodland sites by 210 and 206 times in 2005 and 2006, respectively. Mean total captures at urban sites exceeded those in woodland habitats by 13 and 16 times in 2005 and 2006, respectively. The mean duration (wk) of the flight period did not differ significantly between apple orchards (22.6 +/- 0.6 SE) and urban sites (20.3 +/- 1.2 SE). The onset of flight was somewhat later in New York (around early June) than further south (around early to mid-May), but moth captures continued into October in all states. Captures in apple orchards and at urban sites with higher populations were essentially continuous throughout the flight period, with substantial weekly fluctuations, and tended to show a bimodal pattern with peaks from late May through mid-July and from late August through mid-September. Captures at woodland sites tended to occur predominantly from mid-May through about mid-June and were very sporadic thereafter.

The Land Use and Cover Change in Miombo Woodlands under Community Based Forest Management and Its Implication to Climate Change Mitigation: A Case of Southern Highlands of Tanzania

Directory of Open Access Journals (Sweden)

Z. J. Lupala

2015-01-01

Full Text Available In Tanzania, miombo woodland is the most significant forest vegetation with both ecological and socioeconomic importance. The vegetation has been threatened from land use and cover change due to unsustainable utilization. Over the past two decades, community based forest management (CBFM has been practiced to address the problem. Given the current need to mitigate global climate change, little is known on the influence of CBFM to the land use and cover change in miombo woodlands and therefore compromising climate change mitigation strategies. This study explored the dynamic of land use and covers change and biomass due to CBFM and established the implication to climate change mitigation. The study revealed increasing miombo woodland cover density with decreasing unsustainable utilization. The observed improvement in cover density and biomass provides potential for climate change mitigation strategies. CBFM also developed solidarity, cohesion, and social control of miombo woodlands illegal extraction. This further enhances permanence, reduces leakage, and increases accountability requirement for carbon credits. Collectively with these promising results, good land use plan at village level and introduction of alternative income generating activities can be among the best options to further reduce land use change and biomass loss in miombo woodlands.

UAV – a useful tool for monitoring woodlands

Directory of Open Access Journals (Sweden)

Zmarz Anna

2014-06-01

Full Text Available Unmanned aerial systems are in many countries one of the most dynamically developing branches of technology. They have also been recognized and are being utilized by scientists who find remote sensing indispensable in their work. Today, it is increasingly common to find research teams utilizing so-called drones in field research. Unmanned systems are becoming ever more important for environment monitoring by, on the one hand, providing data from inaccessible or remote areas, and, on the other hand, reducing the human costs required by traditional large field teams while also increasing the efficiency of the work. This paper presents the possibility of utilizing UAVs for image data collection in woodland areas.

Co-adapting societal and ecological interactions following large disturbances in urban park woodlands

Science.gov (United States)

Margaret Carreiro; Wayne Zipperer

2011-01-01

The responses of urban park woodlands to large disturbances provide the opportunity to identify and examine linkages in social-ecological systems in urban landscapes.We propose that the Panarchy model consisting of hierarchically nested adaptive cycles provides a useful framework to evaluate those linkages.We use two case studies as examples – Cherokee Park in...

Where the woodland ends: How edges affect landscape structure and physiological responses of Quercus agrifolia

Science.gov (United States)

de Chant, Timothy Paul

Forests and woodlands are integral parts of ecosystems across the globe, but they are threatened by a variety of factors, including urbanization and introduced forest pathogens. These two forces are fundamentally altering ecosystems, both by removing forest cover and reshaping landscapes. Comprehending how these two processes have changed forest ecosystems is an important step toward understanding how the affected systems will function in the future. I investigated the range of edge effects that result from disturbance brought about by forest pathogens and urbanization in two coastal oak woodlands in Marin County, California. Oak woodlands are a dynamic part of California's landscape, reacting to changes in their biotic and abiotic environments across a range of spatial and temporal scales. Sudden Oak Death, caused by the introduced forest pathogen Phytophthora ramorum, has led to widespread mortality of many tree species in California's oak woodlands. I investigated how the remaining trees respond to such rapid changes in canopy structure (Chapter 2), and my results revealed a forest canopy quick to respond to the new openings. Urbanization, another disturbance regime, operates on a longer time scale. Immediately following urban development, forest edges are strikingly linear, but both forest processes and homeowner actions likely work in concert to disrupt the straight edge (Chapter 3). Forest edges grew more sinuous within 14 years of the initial disturbance, and continued to do so for the remainder of the study, another 21 years. Individual Quercus agrifolia trees also respond to urban edges decades after disturbance (Chapter 4), and their reaction is reflected in declining stable carbon isotope values (delta13C). This change suggests trees may have increased their stomatal conductance in response to greater water availability, reduced their photosynthetic rate as a result of stress, or some combination of both. Edges have far reaching and long lasting effects

Soil respiration and organic carbon dynamics with grassland conversions to woodlands in temperate china.

Directory of Open Access Journals (Sweden)

Wei Wang

Full Text Available Soils are the largest terrestrial carbon store and soil respiration is the second-largest flux in ecosystem carbon cycling. Across China's temperate region, climatic changes and human activities have frequently caused the transformation of grasslands to woodlands. However, the effect of this transition on soil respiration and soil organic carbon (SOC dynamics remains uncertain in this area. In this study, we measured in situ soil respiration and SOC storage over a two-year period (Jan. 2007-Dec. 2008 from five characteristic vegetation types in a forest-steppe ecotone of temperate China, including grassland (GR, shrubland (SH, as well as in evergreen coniferous (EC, deciduous coniferous (DC and deciduous broadleaved forest (DB, to evaluate the changes of soil respiration and SOC storage with grassland conversions to diverse types of woodlands. Annual soil respiration increased by 3%, 6%, 14%, and 22% after the conversion from GR to EC, SH, DC, and DB, respectively. The variation in soil respiration among different vegetation types could be well explained by SOC and soil total nitrogen content. Despite higher soil respiration in woodlands, SOC storage and residence time increased in the upper 20 cm of soil. Our results suggest that the differences in soil environmental conditions, especially soil substrate availability, influenced the level of annual soil respiration produced by different vegetation types. Moreover, shifts from grassland to woody plant dominance resulted in increased SOC storage. Given the widespread increase in woody plant abundance caused by climate change and large-scale afforestation programs, the soils are expected to accumulate and store increased amounts of organic carbon in temperate areas of China.

Long-term changes in organic matter of woodland soils cleared for arable cropping in Zimbabwe

NARCIS (Netherlands)

Zingore, S.; Manyame, C.; Nyamugafata, P.; Giller, K.E.

2005-01-01

Subsistence farmers in Africa depend largely on the soil organic matter to sustain crop productivity. Long-term changes in soil organic carbon and nitrogen were measured after woodland clearance for smallholder subsistence farming or for commercial farming. The contents of organic carbon and

Effects of a Major Tree Invader on Urban Woodland Arthropods

Science.gov (United States)

2015-01-01

Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia), which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera); 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity. PMID:26359665

Effects of a Major Tree Invader on Urban Woodland Arthropods.

Directory of Open Access Journals (Sweden)

Sascha Buchholz

Full Text Available Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia, which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera; 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity.

Effects of a Major Tree Invader on Urban Woodland Arthropods.

Science.gov (United States)

Buchholz, Sascha; Tietze, Hedwig; Kowarik, Ingo; Schirmel, Jens

2015-01-01

Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia), which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera); 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity.

A dynamic compartmental food chain model of radiocaesium transfer to Apodemus sylvaticus in woodland ecosystems

International Nuclear Information System (INIS)

Toal, M.E.; Copplestone, D.; Johnson, M.S.; Jackson, D.; Jones, S.R.

2001-01-01

A study was undertaken to quantify the activity concentrations of 137Cs in Apodemus sylvaticus (the woodmouse) in two woodland sites, Lady Wood and Longrigg Wood, adjacent to British Nuclear Fuels Ltd. (BNFL) Sellafield, Cumbria, UK. A deterministic dynamic compartmental food chain model was also constructed to predict 137Cs activity concentration [Bq kg -1 dry weight (dw)] in A. sylvaticus on a seasonal basis given the activity concentrations in its diet. Within the coniferous woodland site (Lady Wood), significant differences were found between seasons (P x / 2.3 Bq kg -1 dw) being attributed to mycophagy. Fungal concentrations ranged from 2-3213 Bq kg -1 dw. The modelled activity concentrations fell between the confidence intervals of the observed data in four of the six seasonal cohorts sampled. Disparities between predicted and observed activity concentrations are attributed to uncertainties surrounding the fundamental feeding ecology of small mammals

Productivity Contribution of Paleozoic Woodlands to the Formation of Shale-Hosted Massive Sulfide Deposits in the Iberian Pyrite Belt (Tharsis, Spain)

Science.gov (United States)

Fernández-Remolar, David C.; Harir, Mourad; Carrizo, Daniel; Schmitt-Kopplin, Philippe; Amils, Ricardo

2018-03-01

The geological materials produced during catastrophic and destructive events are an essential source of paleobiological knowledge. The paleobiological information recorded by such events can be rich in information on the size, diversity, and structure of paleocommunities. In this regard, the geobiological study of late Devonian organic matter sampled in Tharsis (Iberian Pyrite Belt) provided some new insights into a Paleozoic woodland community, which was recorded as massive sulfides and black shale deposits affected by a catastrophic event. Sample analysis using TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometer), and complemented by GC/MS (Gas Chromatrograph/Mass Spectrometer) identified organic compounds showing a very distinct distribution in the rock. While phytochemical compounds occur homogeneously in the sample matrix that is composed of black shale, the microbial-derived organics are more abundant in the sulfide nodules. The cooccurrence of sulfur bacteria compounds and the overwhelming presence of phytochemicals provide support for the hypothesis that the formation of the massive sulfides resulted from a high rate of vegetal debris production and its oxidation through sulfate reduction under suboxic to anoxic conditions. A continuous supply of iron from hydrothermal activity coupled with microbial activity was strictly necessary to produce this massive orebody. A rough estimate of the woodland biomass was made possible by accounting for the microbial sulfur production activity recorded in the metallic sulfide. As a result, the biomass size of the late Devonian woodland community was comparable to modern woodlands like the Amazon or Congo rainforests.

The ancient blue oak woodlands of California: longevity and hydroclimatic history

Science.gov (United States)

Stahle, D.W.; Griffin, R.D.; Meko, D.M.; Therrell, M.D.; Edmondson, J.R.; Cleaveland, M.K.; Burnette, D.J.; Abatzoglou, J.T.; Redmond, K.T.; Dettinger, M.D.; Cayan, D.R.

2013-01-01

Ancient blue oak trees are still widespread across the foothills of the Coast Ranges, Cascades, and Sierra Nevada in California. The most extensive tracts of intact old-growth blue oak woodland appear to survive on rugged and remote terrain in the south Coast Ranges and on the foothills west and southwest of Mt. Lassen. In our sampling of old-growth stands, most blue oak appear to have recruited to the canopy in the mid- to late-19th century. The oldest living blue oak tree sampled was over 459-years old and several dead blue oak logs had over 500 annual rings. Precipitation sensitive tree-ring chronologies up to 700-years long have been developed from old blue oak trees and logs. Annual ring-width chronologies of blue oak are strongly correlated with cool season precipitation totals, streamflow in the major rivers of California, and the estuarine water quality of San Francisco Bay. A new network of 36 blue oak chronologies records spatial anomalies in growth that arise from latitudinal changes in the mean storm track and location of landfalling atmospheric rivers. These long, climate-sensitive blue oak chronologies have been used to reconstruct hydroclimatic history in California and will help to better understand and manage water resources. The environmental history embedded in blue oak growth chronologies may help justify efforts to conserve these authentic old-growth native woodlands.

Movement pathways and habitat selection by woodland caribou during spring migration

Directory of Open Access Journals (Sweden)

D. Joanne Saher

2005-05-01

Full Text Available Woodland caribou (Rangifer tarandus caribou are a threatened species throughout Canada. Special management is therefore required to ensure habitat needs are met, particularly because much of their current distribution is heavily influenced by resource extraction activities. Although winter habitat is thought to be limiting and is the primary focus of conservation efforts, maintaining connectivity between summer and winter ranges has received little attention. We used global positioning system data from an interprovincial, woodland caribou herd to define migratory movements on a relatively pristine range. Non-linear models indicated that caribou movement during migration was punctuated; caribou traveled for some distance (movement phase followed by a pause (resting/foraging phase. We then developed resource selection functions (RSFs, using case-controlled logistic regression, to describe resting/foraging sites and movement sites, at the landscape scale. The RSFs indicated that caribou traveled through areas that were less rugged and closer to water than random and that resting/foraging sites were associated with older forests that have a greater component of pine, and are further from water than were random available locations. This approach to analyzing animal location data allowed us to identify two patterns of habitat selection (travel and foraging/resting for caribou during the migratory period. Resultant models are important tools for land use planning to ensure that connectivity between caribou summer and winter ranges is maintained.

Diversity and production of Ethiopian dry woodlands explained by climate- and soil- stress gradients

NARCIS (Netherlands)

Eshete, A.; Sterck, F.J.; Bongers, F.

2011-01-01

Dry woodlands cover about 14% of the total African land surface and represent about 25% of the natural vegetation. They are characterized by a seasonal climate, with a dry season of 4–7 months. Large parts of these ecosystems are degrading due to grazing, fire or exploitation by people. We studied

Modeling the effectiveness of tree planting to mitigate habitat loss in blue oak woodlands

Science.gov (United States)

Richard B. Standiford; Douglas McCreary; William Frost

2002-01-01

Many local conservation policies have attempted to mitigate the loss of oak woodland habitat resulting from conversion to urban or intensive agricultural land uses through tree planting. This paper models the development of blue oak (Quercus douglasii) stand structure attributes over 50 years after planting. The model uses a single tree, distance...

Ecology and management of oak woodlands and savannas in the southwestern Borderlands Region

Science.gov (United States)

Gerald J. Gottfried; Peter F. Ffolliott

2013-01-01

Management of the Madrean oak woodlands and the less dense and ecologically different oak savannas must be based on sound ecological information. However, relatively little is known about the Madrean oak ecosystems in spite of the fact that they cover about 80,000 km2 in the southwestern United States and northern Mexico. Emory oak (Quercus emoryi), the dominant tree...

Woodland pond salamander abundance in relation to forest management and environmental conditions in northern Wisconsin

Science.gov (United States)

Deahn M. Donner; Christine A. Ribic; Albert J. Beck; Dale Higgins; Dan Eklund; Susan. Reinecke

2015-01-01

Woodland ponds are important landscape features that help sustain populations of amphibians that require this aquatic habitat for successful reproduction. Species abundance patterns often reflect site-specific differences in hydrology, physical characteristics, and surrounding vegetation. Large-scale processes such as changing land cover and environmental conditions...

Land clearing and greenhouse gas emissions from Jatropha biofuels on African Miombo Woodlands

Energy Technology Data Exchange (ETDEWEB)

Romijn, Henny A., E-mail: h.a.romijn@tue.nl [Technology and Development Studies, Faculty of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2011-10-15

The paper investigates greenhouse gas (GHG) emissions from land use change associated with the introduction of large-scale Jatropha curcas cultivation on Miombo Woodland, using data from extant forestry and ecology studies about this ecosystem. Its results support the notion that Jatropha can help sequester atmospheric carbon when grown on complete wastelands and in severely degraded conditions. Conversely, when introduced on tropical woodlands with substantial biomass and medium/high organic soil carbon content, Jatropha will induce significant emissions that offset any GHG savings from the rest of the biofuel production chain. A carbon debt of more than 30 years is projected. On semi-degraded Miombo the overall GHG balance of Jatropha is found to hinge a lot on the extent of carbon depletion of the soil, more than on the state of the biomass. This finding points to the urgent need for detailed measurements of soil carbon in a range of Miombo sub-regions and similar tropical dryland ecosystems in Asia and Latin America. Efforts should be made to clarify concepts such as 'degraded lands' and 'wastelands' and to refine land allocation criteria and official GHG calculation methodologies for biofuels on that basis.

Land clearing and greenhouse gas emissions from Jatropha biofuels on African Miombo Woodlands

International Nuclear Information System (INIS)

Romijn, Henny A.

2011-01-01

The paper investigates greenhouse gas (GHG) emissions from land use change associated with the introduction of large-scale Jatropha curcas cultivation on Miombo Woodland, using data from extant forestry and ecology studies about this ecosystem. Its results support the notion that Jatropha can help sequester atmospheric carbon when grown on complete wastelands and in severely degraded conditions. Conversely, when introduced on tropical woodlands with substantial biomass and medium/high organic soil carbon content, Jatropha will induce significant emissions that offset any GHG savings from the rest of the biofuel production chain. A carbon debt of more than 30 years is projected. On semi-degraded Miombo the overall GHG balance of Jatropha is found to hinge a lot on the extent of carbon depletion of the soil, more than on the state of the biomass. This finding points to the urgent need for detailed measurements of soil carbon in a range of Miombo sub-regions and similar tropical dryland ecosystems in Asia and Latin America. Efforts should be made to clarify concepts such as 'degraded lands' and 'wastelands' and to refine land allocation criteria and official GHG calculation methodologies for biofuels on that basis.

Exploiting machine learning algorithms for tree species classification in a semiarid woodland using RapidEye image

CSIR Research Space (South Africa)

Adelabu, S

2013-11-01

Full Text Available in semiarid environments. In this study, we examined the suitability of 5-band RapidEye satellite data for the classification of five tree species in mopane woodland of Botswana using machine leaning algorithms with limited training samples. We performed...

Nitrogen dynamics of spring-fed wetland ecosystems of the Sierra Nevada foothills oak woodland

Science.gov (United States)

Randall D. Jackson; Barbara Allen-Diaz

2002-01-01

Spring-fed wetlands are small, highly productive, patchy ecosystems nested within the oak woodland/annual grassland matrix of the Sierra Nevada foothills. In an effort to place these wetlands in a landscape context, we described seasonal variation (1999-2000 growing season) in nitrogen cycling parameters at 6 spring-fed wetland sites of the Sierra Nevada foothill oak...

The Influence of Epiphytic Lichens on the Nutrient Cycling of a Blue Oak Woodland

Science.gov (United States)

Johannes M. Knops; Thomas H. H. Nash III; William H. Schlesinger

1997-01-01

We evaluated the importance of epiphytic lichens in the nutrient cycling of a blue oak (Quercus douglasii) woodland in California. Each oak tree contained an average of 3.8 kg lichen biomass, totaling 590 kg per ha. For comparison, oak leaf biomass was 958 kg per ha. We compared tree growth, volume and composition of throughfall (rainfall falling...

Fire-induced pine woodland to shrubland transitions in Southern Europe may promote shifts in soil fertility.

Science.gov (United States)

Mayor, A G; Valdecantos, A; Vallejo, V R; Keizer, J J; Bloem, J; Baeza, J; González-Pelayo, O; Machado, A I; de Ruiter, P C

2016-12-15

Since the mid of the last century, fire recurrence has increased in the Iberian Peninsula and in the overall Mediterranean basin due to changes in land use and climate. The warmer and drier climate projected for this region will further increase the risk of wildfire occurrence and recurrence. Although the impact of wildfires on soil nutrient content in this region has been extensively studied, still few works have assessed this impact on the basis of fire recurrence. This study assesses the changes in soil organic C and nutrient status of mineral soils in two Southern European areas, Várzea (Northern Portugal) and Valencia (Eastern Spain), affected by different levels of fire recurrence and where short fire intervals have promoted a transition from pine woodlands to shrublands. At the short-term (fire recurrence (one to four fires). At the long-term (>5years), a decline in overall soil fertility with fire recurrence was also observed, with a drop between pine woodlands (one fire) and shrublands (two and three fires), particularly in the soil microsites between shrubs. Our results suggest that the current trend of increasing fire recurrence in Southern Europe may result in losses or alterations of soil organic matter, particularly when fire promotes a transition from pine woodland to shrubland. The results also point to labile organic matter fractions in the intershrub spaces as potential early warning indicators for shifts in soil fertility in response to fire recurrence. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis of lower treeline limber pine (Pinus flexilis) woodland knowledge, research needs, and management considerations

Science.gov (United States)

Robert E. Means

2011-01-01

Lower treeline limber pine woodlands have received little attention in peer-reviewed literature and in management strategies. These ecologically distinct systems are thought to be seed repositories between discontinuous populations in the northern and central Rocky Mountains, serving as seed sources for bird dispersal between distinct mountain ranges. Their position on...

Seasonal changes in plant-water relations influence patterns of leaf display in Miombo woodlands: evidence of water conservative strategies.

Science.gov (United States)

Vinya, Royd; Malhi, Yadvinder; Brown, Nick D; Fisher, Joshua B; Brodribb, Timothy; Aragão, Luiz E O C

2018-06-15

Water availability has frequently been linked to seasonal leaf display in seasonally dry ecosystems, but there have been few ecohydrological investigations of this link. Miombo woodland is a dominant seasonally dry tropical forest ecosystem type in southern Africa; however, there are few data on the relationship between seasonal dynamics in plant-water relations and patterns of leaf display for Miombo woodland. Here we investigate this relationship among nine key Miombo woodland tree species differing in drought tolerance ability and leaf phenology. Results of this study showed that seasonal patterns of leaf phenology varied significantly with seasonal changes in stem water relations among the nine species. Leaf shedding coincided with the attainment of seasonal minimum stem water potential. Leaf flush occurred following xylem rehydration at the peak of the dry season suggesting that endogenous plant factors play a pivotal role in seasonal leaf display in this forest type. Drought-tolerant deciduous species suffered significantly higher seasonal losses in xylem hydraulic conductivity than the drought-intolerant semi-evergreen tree species (P water stress in seasonally dry tropical forests selects for water conservative traits that protect the vulnerable xylem transport system. Therefore, seasonal rhythms in xylem transport dictate patterns of leaf display in seasonally dry tropical forests.

Facilitative and competitive interactions between sympatric cattle, red deer and wild boar in Dutch woodland pastures

NARCIS (Netherlands)

Kuiters, A.T.; Groot Bruinderink, G.W.T.A.; Lammertsma, D.R.

2005-01-01

Use of cattle-grazed and ungrazed woodland pastures by red deer Cervus elaphus Linnaeus, 1758 and wild boar Sus scrofa Linnaeus, 1758 was investigated monthly by measuring dung-deposition rates. Cattle Bos taurus grazed pastures year-round, with peak intensities during the growing season

Aboveground and belowground biomass allocation in native Prosopis caldenia Burkart secondaries woodlands in the semi-arid Argentinean pampas

International Nuclear Information System (INIS)

Risio, Lucia; Herrero, Celia; Bogino, Stella M.; Bravo, Felipe

2014-01-01

The woodlands in the south-west of the Argentinean pampas are dominated by Prosopis Caldenia Burkart (calden). The current deforestation rate of this woodlands is 0.82% per year. Different compensation initiatives have begun that recognize the role of forests as environmental service providers. The financial incentives they offer make it necessary to quantify the amount of carbon stored in the forest biomass. A model for estimating calden biomass was developed. Thirty-eight trees were selected, felled and divided into sections. An equation system was fitted using joint generalized regression to ensure the additivity property. A weighted regression was used to avoid heteroscedasticity. In these woodlands fire is the main disturbance and it can modify tree allometry, due this all models included the area of the base of the stem and tree height as independent variables since it indirectly collects this variability. Total biomass and the stem fraction had the highest R2 A dj. values (0.75), while branches with a diameter less than 7 cm had the lowest (0.58). Tree biomass was also analyzed by partitioning into the basic fractions of stem, crown, roots, and the root/shoot ratio. Biomass allocation was greatest in the crown fraction and the mean root/shoot ratio was 0.58. The carbon stock of the caldenales considering only calden tree biomass is 20.2 Mg ha −1 . While the overall carbon balance of the region is negative (deforestation and biomass burning, the remnant forested area has increased their calden density and in an indirect way his carbon sequestration capacity could also be increased. - Highlights: • A model for estimating aboveground and belowground Prosopis caldenia biomass was developed. • Biomass allocation into the tree and the root/shoot ratio were analyzed. • The equation systems presented had made it possible to more accurately estimate the biomass stored in calden woodlands

Woodland salamanders as metrics of forest ecosystem recovery: a case study from California’s redwoods

Science.gov (United States)

Hart Welsh; Garth Hodgson

2013-01-01

Woodland (Plethodontid) salamanders occur in huge numbers in healthy forests in North America where the abundances of many species vary along successional gradients. Their high numbers and trophic role as predators on shredder and decomposer arthropods influence nutrient and carbon pathways at the leaf litter/soil interface. Their extreme niche conservatism and low...

Leaf, branch, stand and landscape scale measurements of volatile organic compound fluxes from U. S. woodlands

Energy Technology Data Exchange (ETDEWEB)

Guenther, A.; Greenberg, J.; Harley, P.; Helmig, D.; Klinger, L.; Vierling, L.; Zimmerman, P. [National Center for Atmospheric Research, Boulder, CO (United States). Atmospheric Chemistry Div.; Geron, C. [Environmental Protection Agency, Research Triangle Park, NC (United States)

1996-01-01

Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands. Fluxes from individual leaves and branches were estimated with enclosure techniques and used to initialize and evaluate VOC emission model estimates. Ambient measurements were used to estimate above canopy fluxes for entire stands. A total of 78 VOCs were identified, with hexenol derivatives being the most commonly observed oxygenated compounds. There was also evidence of high rates of isoprene emission and high rates of monoterpenes in some genera of trees. Model predictions of diurnal variations were within + or - 35 per cent of observed flux variations. Fluxes predicted by a recent version of a biogenic emission model were within 10 per cent to 50 per cent of observed fluxes, leading to the conclusion that existing databases can provide isoprene and monoterpene emission rate potentials within acceptable limits for the dominant plant species at these three woodland sites. 21 refs., 5 tabs., 2 figs.

Woodland reserves within an urban agglomeration as important refuges for small mammals

Directory of Open Access Journals (Sweden)

Gryz Jakub

2017-03-01

Full Text Available The aim of the study was to determine the species richness (S, Chao- 1 index and diversity (Shannon-Wiener H’ index, diversity profiles of small mammal assemblages in woodland reserves in an urban agglomeration and to compare the similarity of assemblages (with the use of Ward’s method in terms of proportions of small mammals connected to the habitats of different level of naturalness. The work was conducted from 2004-2015 at 9 woodland reserves in Warsaw (Poland. On the basis of the analysis of pellets of tawny owls Strix aluco, 2792 individuals were identified (24 species. Reserves supported from 7 to 16 of the small mammal species, the highest overall number of species estimated (Chao-1 was 19. Species present in every reserve were Apodemus flavicollis, A. agrarius, Rattus norvegicus, Sorex araneus and Talpa europaea. Least frequent were Microtus agrestis and M. subterraneus. Seven species of bats were detected. Species diversity was lower in the biggest forest complexes, where forest rodents dominated small mammal assemblage. The heterogeneity of habitats within reserve and in the surroundings, in combination with limited human-interference, resulted in an increase in the species diversity. Overall, the reserves under study were an important refuge for small mammals within the Warsaw agglomeration. However, safeguarding of adjacent areas against excessive anthropogenic change is needed and ecological corridors that link different areas need to be retained.

Habitat selection and post-release movement of reintroduced brown treecreeper individuals in restored temperate woodland.

Directory of Open Access Journals (Sweden)

Victoria A Bennett

Full Text Available It is essential to choose suitable habitat when reintroducing a species into its former range. Habitat quality may influence an individual's dispersal decisions and also ultimately where they choose to settle. We examined whether variation in habitat quality (quantified by the level of ground vegetation cover and the installation of nest boxes influenced the movement, habitat choice and survival of a reintroduced bird species. We experimentally reintroduced seven social groups (43 individuals of the brown treecreeper (Climacteris picumnus into two nature reserves in south-eastern Australia. We radio-tracked 18 brown treecreepers from release in November 2009 until February 2010. We observed extensive movements by individuals irrespective of the release environment or an individual's gender. This indicated that individuals were capable of dispersing and actively selecting optimum habitat. This may alleviate pressure on wildlife planners to accurately select the most optimum release sites, so long as the species' requirements are met. There was significant variation in movement between social groups, suggesting that social factors may be a more important influence on movement than habitat characteristics. We found a significant effect of ground vegetation cover on the likelihood of settlement by social groups, with high rates of settlement and survival in dry forests, rather than woodland (where the species typically resides, which has implications for the success of woodland restoration. However, overall the effects of variation in habitat quality were not as strong as we had expected, and resulted in some unpredicted effects such as low survival and settlement in woodland areas with medium levels of ground vegetation cover. The extensive movement by individuals and unforeseen effects of habitat characteristics make it difficult to predict the outcome of reintroductions, the movement behaviour and habitat selection of reintroduced individuals

Woodland Mapping at Single-Tree Levels Using Object-Oriented Classification of Unmanned Aerial Vehicle (uav) Images

Science.gov (United States)

Chenari, A.; Erfanifard, Y.; Dehghani, M.; Pourghasemi, H. R.

2017-09-01

Remotely sensed datasets offer a reliable means to precisely estimate biophysical characteristics of individual species sparsely distributed in open woodlands. Moreover, object-oriented classification has exhibited significant advantages over different classification methods for delineation of tree crowns and recognition of species in various types of ecosystems. However, it still is unclear if this widely-used classification method can have its advantages on unmanned aerial vehicle (UAV) digital images for mapping vegetation cover at single-tree levels. In this study, UAV orthoimagery was classified using object-oriented classification method for mapping a part of wild pistachio nature reserve in Zagros open woodlands, Fars Province, Iran. This research focused on recognizing two main species of the study area (i.e., wild pistachio and wild almond) and estimating their mean crown area. The orthoimage of study area was consisted of 1,076 images with spatial resolution of 3.47 cm which was georeferenced using 12 ground control points (RMSE=8 cm) gathered by real-time kinematic (RTK) method. The results showed that the UAV orthoimagery classified by object-oriented method efficiently estimated mean crown area of wild pistachios (52.09±24.67 m2) and wild almonds (3.97±1.69 m2) with no significant difference with their observed values (α=0.05). In addition, the results showed that wild pistachios (accuracy of 0.90 and precision of 0.92) and wild almonds (accuracy of 0.90 and precision of 0.89) were well recognized by image segmentation. In general, we concluded that UAV orthoimagery can efficiently produce precise biophysical data of vegetation stands at single-tree levels, which therefore is suitable for assessment and monitoring open woodlands.

Impacts of wildfire severity on hydraulic conductivity in forest, woodland, and grassland soils (Chapter 7)

Science.gov (United States)

Daniel G. Neary

2011-01-01

Forest, woodland, and grassland watersheds throughout the world are major sources of high quality water for human use because of the nature of these soils to infiltrate, store, and transmit most precipitation instead of quickly routing it to surface runoff. This characteristic of these wildland soils is due to normally high infiltration rates, porosities, and hydraulic...

An Effective Method for Detecting Potential Woodland Vernal Pools Using High-Resolution LiDAR Data and Aerial Imagery

Science.gov (United States)

Effective conservation of woodland vernal pools – important components of regional amphibian diversity and ecosystem services – depends on locating and mapping these pools accurately. Current methods for identifying potential vernal pools are primarily based on visual interpretat...

Behavioural strategies towards human disturbances explain individual performance in woodland caribou.

Science.gov (United States)

Leclerc, Martin; Dussault, Christian; St-Laurent, Martin-Hugues

2014-09-01

Behavioural strategies may have important fitness, ecological and evolutionary consequences. In woodland caribou, human disturbances are associated with higher predation risk. Between 2004 and 2011, we investigated if habitat selection strategies of female caribou towards disturbances influenced their calf's survival in managed boreal forest with varying intensities of human disturbances. Calf survival was 53% and 43% after 30 and 90 days following birth, respectively, and 52% of calves that died were killed by black bear. The probability that a female lose its calf to predation was not influenced by habitat composition of her annual home range, but decreased with an increase in proportion of open lichen woodland within her calving home range. At the local scale, females that did not lose their calf displayed stronger avoidance of high road density areas than females that lost their calf to predation. Further, females that lost their calf to predation and that had a low proportion of ≤5-year-old cutovers within their calving home range were mostly observed in areas where these young cutovers were locally absent. Also, females that lost their calf to predation and that had a high proportion of ≤5-year-old cutovers within their calving home range were mostly observed in areas with a high local density of ≤5-year-old cutovers. Our study demonstrates that we have to account for human-induced disturbances at both local and regional scales in order to further enhance effective caribou management plans. We demonstrate that disturbances not only impact spatial distribution of individuals, but also their reproductive success.

Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

Science.gov (United States)

Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardgree, Stuart; Strand, Eva

2013-01-01

Woody encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p 2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 – 143.6 kg and 0.5 – 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

Radionuclides in redistributed sediments and ash from the Las Conchas fire in Northern New Mexico

International Nuclear Information System (INIS)

Matteson, B.S.; Oldham, Jr.W.J.

2013-01-01

The 2011 Las Conchas fire burned 632 km 2 of ponderosa pine forests and pinon-juniper woodlands in the Jemez Mountains in north central New Mexico. In the weeks following the fire, heavy rainfall caused extensive flooding and erosion of surface soil and ash from the affected areas. Samples from mud and ash flows were collected and analyzed for 137 Cs and Pu, which were originally deposited as global fallout during the era of atmospheric nuclear testing. The mean concentrations for 238 Pu, 239,240 Pu and 137 Cs were 0.18 ± 0.05, 4.16 ± 1.95, and 111 ± 56 mBq/g, respectively. 239,240 Pu and 137 Cs are significantly elevated above non-fire affected regional background levels. (author)

Growing season boundary layer climate and surface exchanges in a subarctic lichen woodland

Science.gov (United States)

Fitzjarrald, David R.; Moore, Kathleen E.

1994-01-01

Between June and August 1990, observations were made at two surface micrometeorological towers near Schefferville Quebec (54 deg 52 min N, 66 deg 40.5 min W), one in a fen and one in the subarctic lichen woodland, and at four surface climatological stations. Data from these surface stations were supplemented by regular radiosonde launches. Supporting measurements of radiative components and soil temperatures allowed heat and moisture balances to be obtained at two sites. The overall surface meteorological experiment design and results of micrometeorological observations made on a 30-m tower in the lichen woodland are presented here. Seasonal variation in the heat and water vapor transport characteristics illustrate the marked effect of the late summer climatological shift in air mass type. During the first half of the summer, average valley sidewalls only 100 m high are sufficient to channel winds along the valley in the entire convective boundary layer. Channeling effects at the surface, known for some time at the long-term climate station in Schefferville, are observed both at ridge top and in the valley, possibly the response of the flow to the NW-SE orientation of valleys in the region. Diurnal surface temperature amplitude at ridge top (approximately equal to 10 C) was found to be half that observed in the valley. Relatively large differences in precipitation among these stations and the climatological station at Schefferville airport were observed and attributed to the local topography. Eddy correlation observations of the heat, moisture and momentum transports were obtained from a 30-m tower above a sparse (approximately equal to 616 stems/ha) black spruce lichen woodland. Properties of the turbulent surface boundary layer agree well with previous wind tunnel studies over idealized rough surfaces. Daytime Bowen ratios of 2.5-3 are larger than those reported in previous studies. Surface layer flux data quality was assessed by looking at the surface layer heat

Afforestation of Boreal Open Woodlands: Early Performance and Ecophysiology of Planted Black Spruce Seedlings

OpenAIRE

Tremblay, Pascal; Boucher, Jean-Francois; Tremblay, Marc; Lord, Daniel

2013-01-01

Open lichen woodlands (LWs) are degraded stands that lack the ability to regenerate naturally due to a succession of natural and/or anthropogenic disturbances. As they represent both interesting forest restoration and carbon sequestration opportunities, we tested disc scarification and planting of two sizes of containerized black spruce (Picea mariana Mill. (BSP)) seedlings for their afforestation. We compared treatment of unproductive LWs to reforestation of harvested, closed-crown black spr...

WOODLAND MAPPING AT SINGLE-TREE LEVELS USING OBJECT-ORIENTED CLASSIFICATION OF UNMANNED AERIAL VEHICLE (UAV IMAGES

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A. Chenari

2017-09-01

Full Text Available Remotely sensed datasets offer a reliable means to precisely estimate biophysical characteristics of individual species sparsely distributed in open woodlands. Moreover, object-oriented classification has exhibited significant advantages over different classification methods for delineation of tree crowns and recognition of species in various types of ecosystems. However, it still is unclear if this widely-used classification method can have its advantages on unmanned aerial vehicle (UAV digital images for mapping vegetation cover at single-tree levels. In this study, UAV orthoimagery was classified using object-oriented classification method for mapping a part of wild pistachio nature reserve in Zagros open woodlands, Fars Province, Iran. This research focused on recognizing two main species of the study area (i.e., wild pistachio and wild almond and estimating their mean crown area. The orthoimage of study area was consisted of 1,076 images with spatial resolution of 3.47 cm which was georeferenced using 12 ground control points (RMSE=8 cm gathered by real-time kinematic (RTK method. The results showed that the UAV orthoimagery classified by object-oriented method efficiently estimated mean crown area of wild pistachios (52.09±24.67 m2 and wild almonds (3.97±1.69 m2 with no significant difference with their observed values (α=0.05. In addition, the results showed that wild pistachios (accuracy of 0.90 and precision of 0.92 and wild almonds (accuracy of 0.90 and precision of 0.89 were well recognized by image segmentation. In general, we concluded that UAV orthoimagery can efficiently produce precise biophysical data of vegetation stands at single-tree levels, which therefore is suitable for assessment and monitoring open woodlands.

The quantification and distribution of pollution Pb at a woodland in rural south central Ontario, Canada

International Nuclear Information System (INIS)

Watmough, Shaun A.; Hutchinson, Thomas C.

2004-01-01

Lead concentrations and Pb isotope ratios were measured in the forest floor, mineral soil and vegetation at a white pine and a sugar maple stand in a woodland in south central Ontario. Lead concentrations decreased and 206 Pb/ 207 Pb ratios increased with mineral soil depth reflecting the mixing of pollution and natural Pb sources. Lead concentrations and 206 Pb/ 207 Pb ratios at 20-30 cm depth were ∼6-7 mg/kg and 1.31-1.32, respectively. Assuming an integrated 206 Pb/ 207 Pb ratio in deposition over time of 1.18, estimated from lichen measurements and published data for the region, approximately 65% of Pb in the surface (0-1 cm) mineral soil is from anthropogenic sources. Approximately 90% of pollution Pb is found in the 0-10 cm soil layer (Ah) and less than 3% of the pollution Pb is present in the forest biomass and mull-type forest floor combined. Despite low Pb concentrations in vegetation ( 2 , respectively. - The distribution of pollution lead was determined at a woodland through the use of stable leads isotopes

National recovery strategy for woodland caribou (Rangifer tarandus caribou, boreal population, in Canada

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Dave Hervieux

2007-04-01

Full Text Available Recovery planning for the boreal population of woodland caribou is a complex task, spanning eight Canadian provinces and territories. To accommodate unique situations across the country, recovery planning for this Species at Risk Act-listed threatened species is occurring at both provincial/ territorial and national levels. The national recovery strategy strives to identify nationally important issues and provide direction for provinces and territories as they plan and implement boreal caribou recovery within their jurisdictions. The national vision is to conserve and recover boreal caribou and their habitat across Canada. Specific goals are to: 1 Prevent extirpation of local boreal caribou populations from all existing caribou ranges; and 2 Maintain or enhance local boreal caribou populations at or to self-sustaining levels within all existing caribou ranges; and 3 Maintain or enhance boreal caribou habitat to support self-sustaining local populations. Nineteen broad national approaches are identified. These approaches include items relating to: habitat planning and management, caribou population monitoring and management, management of human-caused mortality, management of other wildlife species, consideration of government legislation and policy,promotion of stewardship and public outreach, and research. Specific outcomes are provided for each stated recovery approach. For more information on Canada's national recovery strategy for the boreal population of woodland caribou please see www.speciesatrisk.gc.ca/recovery/default_e.cfm

Challenging the Woodfuel Crisis in West African Woodlands

DEFF Research Database (Denmark)

Hansfort, Sofie Louise; Mertz, Ole

2011-01-01

Fear of an upcoming woodfuel crisis caused by increasing woodfuel consumption in Bamako has had great influence on forestry policies aiming to reduce the impacts of urban woodfuel consumption. During the last 20 years, energy gap analyses—the relationship between supply and demand of woodfuels......—have been produced by the government of Mali to prove the impacts of woodfuel consumption in Bamako on surrounding woodlands. This study evaluates the methodology and data used to describe this woodfuel crisis through a comparison with regional and historical data. The results of the energy gap analyses...... are challenged by using different estimates of woody resource availability and woodfuel consumption to create best and worst case scenarios. These show either high surpluses or high deficits with a difference of 2.7 million tons/yr. The woodfuel system of Bamako is highly dynamic and it is very difficult...

Wild Harvests from Scottish Woodlands Social, cultural and economic values of contemporary non-timber forest products

Science.gov (United States)

Marla Emery; Suzanne Martin; Alison Dyke; Alison Dyke

2006-01-01

More than 30 people were interviewed about the wild edibles, medicinals, and craft materials they collect and the part that collecting plays in their lives as part of the Wild Harvests from Scottish Woodlands project. Interviews were conducted in autumn 2004. Collecting non-timber forest products (NTFPs) is a source of joy and satisfaction for many of those interviewed...

Decadal changes in phenology of peak abundance patterns of woodland pond salamanders in northern Wisconsin

Science.gov (United States)

Donner, Deahn M.; Ribic, Christine; Beck, Albert J.; Higgins, Dale; Eklund, Dan; Reinecke, Susan

2015-01-01

Woodland ponds are important landscape features that help sustain populations of amphibians that require this aquatic habitat for successful reproduction. Species abundance patterns often reflect site-specific differences in hydrology, physical characteristics, and surrounding vegetation. Large-scale processes such as changing land cover and environmental conditions are other potential drivers influencing amphibian populations in the Upper Midwest, but little information exists on the combined effects of these factors. We used Blue-spotted (Ambystoma laterale Hallowell) and Spotted Salamander (A. maculatum Shaw) monitoring data collected at the same woodland ponds thirteen years apart to determine if changing environmental conditions and vegetation cover in surrounding landscapes influenced salamander movement phenology and abundance. Four woodland ponds in northern Wisconsin were sampled for salamanders in April 1992-1994 and 2005-2007. While Blue-spotted Salamanders were more abundant than Spotted Salamanders in all ponds, there was no change in the numbers of either species over the years. However, peak numbers of Blue-spotted Salamanders occurred 11.7 days earlier (range: 9-14 days) in the 2000s compared to the 1990s; Spotted Salamanders occurred 9.5 days earlier (range: 3 - 13 days). Air and water temperatures (April 13- 24) increased, on average, 4.8°C and 3.7°C, respectively, between the decades regardless of pond. There were no discernible changes in canopy openness in surrounding forests between decades that would have warmed the water sooner (i.e., more light penetration). Our finding that salamander breeding phenology can vary by roughly 10 days in Wisconsin contributes to growing evidence that amphibian populations have responded to changing climate conditions by shifting life-cycle events. Managers can use this information to adjust monitoring programs and forest management activities in the surrounding landscape to avoid vulnerable amphibian

The influence of canopy, sky condition, and solar angle on light quality in a longleaf pine woodland

Science.gov (United States)

Stephen D. Pecot; Stephen B. Horsley; Michael A. Battaglia; Robert J. Mitchell

2005-01-01

Light transmittance estimates under open, heterogeneous woodland canopies such as those of longleaf pine (Pinus palustris Mill.) forests report high spatial and temporal variation in the quantity of the light environment. In addition, light quality, that is, the ratio of red to far-red light (R:FR), regulates important aspects of plant...

Plant and soil carbon accumulation following fire in Mediterranean woodlands in Spain.

Science.gov (United States)

Kaye, Jason Philip; Romanyà, Joan; Vallejo, V Ramón

2010-10-01

We measured plant and soil carbon (C) storage following canopy-replacing wildfires in woodlands of northeastern Spain that include an understory of shrubs dominated by Quercus coccifera and an overstory of Pinus halepensis trees. Established plant succession models predict rapid shrub recovery in these ecosystems, and we build on this model by contrasting shrub succession with long-term C storage in soils, trees, and the whole ecosystem. We used chronosequence and repeated sampling approaches to detect change over time. Aboveground plant C increased from fire, which is substantially less than the 5,942 ± 487 g C m(-2) (mean ±1 standard error) in unburned sites. As expected, shrubs accumulated C rapidly, but the capacity for C storage in shrubs was 20 years post fire, and accounted for all of the difference in plant C between older burned sites and unburned sites. In contrast, soil C was initially higher in burned sites (~4,500 g C m(-2)) than in unburned sites (3,264 ± 261 g C m(-2)) but burned site C declined to unburned levels within 10 years after fire. Combining these results with prior research suggests two states for C storage. When pine regeneration is successful, ~9,200 g C m(-2) accumulate in woodlands but when tree regeneration fails (due to microclimatic stress or short fire return intervals), ecosystem C storage of ~4,000 g C m(-2) will occur in the resulting shrublands.

Roost selection by barbastelle bats (Barbastella barbastellus, Chiroptera: Vespertilionidae in beech woodlands of central Italy

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Danilo Russo

2003-10-01

Full Text Available The barbastelle bat, Barbastella barbastellus (Schreber, 1774 is a medium-sized, tree-dwelling vespertilionid classified as ?Endangered? in Italy; in western Europe it may be one of the rarest bat species. B. barbastellus shows roosting preferences that should be regarded as a key point in conservation protocols. We examined roost selection in a breeding population of B. barbastellus from the Abruzzo Lazio and Molise National Park (central Italy at three levels: woodland structure and management type; tree characteristics; and cavity characteristics. In 2001-2002, we fitted 31 adult B. barbastellus (29 lactating females, one pregnant female and one male with 0.48g radio-tags and tracked them to their roost-trees. The bats were tracked for 4.5 ± 3.7 days (range: 0-12 days. We located 33 roosts used by 25 subjects (1.8±1.2 roosts/bat, range 1-5. The bats switched roosts frequently: 13 bats used more than one tree over the study period. A chi-square analysis showed that the roosts were not distributed at random across woodland categories: unmanaged woodland was positively selected, whereas shelterwood-harvested woodland was used in proportion to its availability, and ?pastures+scattered trees? was avoided. Twenty out of 33 roost trees were dead Fagus sylvatica trees; conversely, living F. sylvatica dominated in a tree sample obtained at random; dead trees were used more than expected (Χ² test, P <0.001. Overall, roost trees were significantly taller and had a larger diameter at breast?s height and more cavities than random trees; they also had a lower percent canopy closure than random trees. To highlight which variables were actually associated with selection, we devised a logistic regression model. The full model was significant (P <0.001; removal of tree type and tree height affected the model significantly, but the other variables did not produce detectable effects. The

Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

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P. Pinho

2012-03-01

Full Text Available Nitrogen (N has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds such as critical loads (deposition fluxes and levels (concentrations can be established. Few studies have assessed these thresholds for semi-natural Mediterranean ecosystems. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands. We have considered changes in epiphytic lichen communities, one of the most sensitive comunity indicators of excessive N in the atmosphere. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done for a Mediterranean climate in evergreen cork-oak woodlands, based on the relation between lichen functional diversity and modelled N deposition for critical loads and measured annual atmospheric ammonia concentrations for critical levels, evaluated downwind from a reduced N source (a cattle barn. Modelling the highly significant relationship between lichen functional groups and annual atmospheric ammonia concentration showed the critical level to be below 1.9 μg m⁻³, in agreement with recent studies for other ecosystems. Modelling the highly significant relationship between lichen functional groups and N deposition showed that the critical load was lower than 26 kg (N ha⁻¹ yr⁻¹, which is within the upper range established for other semi-natural ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should aid development of policies to protect Mediterranean woodlands from the initial effects of excessive N.

Drought responses of conifers in ecotone forests of northern Arizona: tree ring growth and leaf delta13C.

Science.gov (United States)

Adams, Henry D; Kolb, Thomas E

2004-07-01

We sought to understand differences in tree response to meteorological drought among species and soil types at two ecotone forests in northern Arizona, the pinyon-juniper woodland/ponderosa pine ecotone, and the higher elevation, wetter, ponderosa pine/mixed conifer ecotone. We used two approaches that provide different information about drought response: the ratio of standardized radial growth in wet years to dry years (W:D) for the period between years 1950 and 2000 as a measure of growth response to drought, and delta13C in leaves formed in non-drought (2001) and drought (2002) years as a measure of change in water use efficiency (WUE) in response to drought. W:D and leaf delta13C response to drought for Pinus edulis and P. ponderosa did not differ for trees growing on coarse-texture soils derived from cinders compared with finer textured soils derived from flow basalts or sedimentary rocks. P. ponderosa growing near its low elevation range limit at the pinyon-juniper woodland/ponderosa pine ecotone had a greater growth response to drought (higher W:D) and a larger increase in WUE in response to drought than co-occurring P. edulis growing near its high elevation range limit. P. flexilis and Pseudotsuga menziesii growing near their low elevation range limit at the ponderosa pine/mixed conifer ecotone had a larger growth response to drought than co-occurring P. ponderosa growing near its high elevation range limit. Increases in WUE in response to drought were similar for all species at the ponderosa pine/mixed conifer ecotone. Low elevation populations of P. ponderosa had greater growth response to drought than high-elevation populations, whereas populations had a similar increase in WUE in response to drought. Our findings of different responses to drought among co-occurring tree species and between low- and high-elevation populations are interpreted in the context of drought impacts on montane coniferous forests of the southwestern USA.

Measuring canopy loss and climatic thresholds from an extreme drought along a fivefold precipitation gradient across Texas.

Science.gov (United States)

Schwantes, Amanda M; Swenson, Jennifer J; González-Roglich, Mariano; Johnson, Daniel M; Domec, Jean-Christophe; Jackson, Robert B

2017-12-01

Globally, trees are increasingly dying from extreme drought, a trend that is expected to increase with climate change. Loss of trees has significant ecological, biophysical, and biogeochemical consequences. In 2011, a record drought caused widespread tree mortality in Texas. Using remotely sensed imagery, we quantified canopy loss during and after the drought across the state at 30-m spatial resolution, from the eastern pine/hardwood forests to the western shrublands, a region that includes the boundaries of many species ranges. Canopy loss observations in ~200 multitemporal fine-scale orthophotos (1-m) were used to train coarser Landsat imagery (30-m) to create 30-m binary statewide canopy loss maps. We found that canopy loss occurred across all major ecoregions of Texas, with an average loss of 9.5%. The drought had the highest impact in post oak woodlands, pinyon-juniper shrublands and Ashe juniper woodlands. Focusing on a 100-km by ~1,000-km transect spanning the State's fivefold east-west precipitation gradient (~1,500 to ~300 mm), we compared spatially explicit 2011 climatic anomalies to our canopy loss maps. Much of the canopy loss occurred in areas that passed specific climatic thresholds: warm season anomalies in mean temperature (+1.6°C) and vapor pressure deficit (VPD, +0.66 kPa), annual percent deviation in precipitation (-38%), and 2011 difference between precipitation and potential evapotranspiration (-1,206 mm). Although similarly low precipitation occurred during the landmark 1950s drought, the VPD and temperature anomalies observed in 2011 were even greater. Furthermore, future climate data under the representative concentration pathway 8.5 trajectory project that average values will surpass the 2011 VPD anomaly during the 2070-2099 period and the temperature anomaly during the 2040-2099 period. Identifying vulnerable ecological systems to drought stress and climate thresholds associated with canopy loss will aid in predicting how forests will

An accidental resource: the social ecological system framework applied to small wetlands in Sierran foothill oak woodlands

Science.gov (United States)

Tracy V. Hruska; Lynn Huntsinger; Jose L. Oviedo

2015-01-01

An ongoing study of the small wetlands in the northern Sierra Nevada foothill oak woodlands that provide habitat for the state-threatened California black rail (Laterallus jamaicensis coturniculus) offers an example of the way that the social ecological systems (SES) framework can be used to analyze a natural resource problem. At the outset, it was...

What makes a good neighborhood? Interaction of spatial scale and fruit density in the predator satiation dynamics of a masting juniper tree.

Science.gov (United States)

Mezquida, Eduardo T; Olano, José Miguel

2013-10-01

Spatio-temporal variability in fruit production (masting) has been regarded as a key mechanism to increase plant fitness by reducing seed predation. However, considerably more effort has been devoted into understanding the consequences of temporal rather than spatial variations in fruit crop for plant fitness. In order to simultaneously evaluate both components, we quantify fruit production and pre-dispersal damage by three arthropod species (mites, chalcid wasps and moths) in the Spanish juniper (Juniperus thurifera) during 3 years in a spatially explicit context. Our aims were to assess (1) the interaction between fruit production and pre-dispersal fruit damage by arthropods, (2) the potential interference or competition between arthropods, and (3) the form of the phenotypic selection exerted by arthropods on fruit traits considering the spatial context. Arthropods damaged a substantial fraction of fruits produced by Spanish juniper with levels of damage showing sharp inter-annual variations. Fruit damage by mites was negatively related to yearly fruit crop and positively correlated at individual trees fruiting in consecutive years. Increased interspecific interference was an additional consequence of reduced fruit availability during small crop years. During a masting year, fruit damage by less mobile species such as mites was negatively affected by tree crop size, and no spatial structure was observed for mite damage. The incidence of chalcid wasps was low, so the spatial pattern of seed predation was unclear, and no preferences for fruit or seed traits were detected. Conversely, moths selected larger fruits and their incidence on trees was spatially aggregated up to 20 m, with predation levels being negatively affected by fruit abundance at the patch level, suggesting a positive density-dependent effect of neighbors on fruit output. These results highlight the importance of including the spatial component to understand complex species interactions at local

The Influence of Rainfall, Vegetation, Elephants and People on Fire Frequency of Miombo Woodlands, Northern Mozambique

Science.gov (United States)

Ribeiro, N. S.; Okin, G. S.; Shugart, H. H.; Swap, R. J.

2008-12-01

Miombo woodlands are important in southern Africa as they occupy over 50% of the land and, their good and services support a large proportion of people in the region. Anthropogenic fires occur in miombo every year especially in the dry season (May - October). This study explores the influence of annual rainfall, elephant density, human density and corridors, and vegetation on the fire frequency. It was carried out in Niassa Reserve located in northern Mozambique, the largest and more pristine conservation area of miombo woodlands in the world. We used a time series analysis and statistical t-test of MODIS-derived Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) to explore the relationship between biomass and fire frequency. The influence of rainfall, elephants, people and vegetation on fire return was explored using a stepwise logistic regression analysis. The results of this study indicate that fire frequency is higher in places with high biomass at beginning of the dry season. In these areas fire seems to be more intense and to strongly reduce biomass in the late dry season. Land cover is the strongest predictor of fire frequency, but elephant density, annual rainfall and human corridors are also important.

Modeling bidirectional reflectance of forests and woodlands using Boolean models and geometric optics

Science.gov (United States)

Strahler, Alan H.; Jupp, David L. B.

1990-01-01

Geometric-optical discrete-element mathematical models for forest canopies have been developed using the Boolean logic and models of Serra. The geometric-optical approach is considered to be particularly well suited to describing the bidirectional reflectance of forest woodland canopies, where the concentration of leaf material within crowns and the resulting between-tree gaps make plane-parallel, radiative-transfer models inappropriate. The approach leads to invertible formulations, in which the spatial and directional variance provides the means for remote estimation of tree crown size, shape, and total cover from remotedly sensed imagery.

Population ecology of two woodland caribou herds in the southern Yukon

Directory of Open Access Journals (Sweden)

Richard Farnell

1996-01-01

Full Text Available Since the mid 1980's, the Aishihik herd of woodland caribou (Rangifer tarandus caribou declined from approximately 1500 to 583 animals. During the same period a nearby herd, the Wolf Lake Herd increased from approximately 664 to 1249 animals. This paper compares aspects of the ecology of these two herds to determine how these relationships conform to a general model of caribou population ecology described by Seip (1992. Comparisons include caribou demographic characteristics and distribution patterns, predator densities, abundance of alternate prey, human hunting and snow depth on caribou winter range. Ecological differences between herds were apparent in the ratio of prime bulls to cows, the abundance of moose (Alces alces, the occurrence of coyotes (Canis latrans, late winter snow conditions, and access to hunting. We hypothesize that the Wolf Lake herd was able to grow because wolves {Canis lupus preyed mainly on the relatively abundant moose population. A highly clumped winter caribou distribution may have further reduced the impact of wolf predation on the Wolf Lake herd. In contrast, the decline of the Aishihik herd was accompanied by a relative scarcity of moose, few prime aged caribou bulls probably due to a more liberal trophy harvest, and wider late-winter dispersion that offered wolves greater access to caribou. The decline may have been exaggerated by the peak in the snowshoe hare (Lepus americanus cycle which may have temporarily improved wolf pup survival. We suspect that moose are normally the primary prey of wolves in the Yukon and that a decline in moose eventually results in their being too scarce to offer an economical prey choice, prompting a prey switch to caribou. Results of our analyses conform incompletely to Seip's (1992 model for woodland caribou population ecology, particularly because the Wolf Lake herd prospered where moose were relatively abundant.

Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

Science.gov (United States)

Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardegree, Stuart; Strand, Eva

2013-07-01

encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p < 0.001, RMSE = 0.58 kg). The predicted mean aboveground woody carbon storage for the study area was 677 g/m2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 - 143.6 kg and 0.5 - 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

Stand development and population dynamics of curlleaf mountain mahogany (Cercocarpus ledifolius Nutt.) woodlands in Utah's Bear River Mountains

Science.gov (United States)

Seth A. Ex; Robert DeRose; James N. Long

2011-01-01

Curlleaf mountain mahogany (Cercocarpus ledifolius Nutt.) is a little-studied woodland tree that occurs in pure stands throughout the Intermountain West. Stand development and population dynamics of this species are poorly understood, despite their relevance to management. We describe here the development of stand age structures and population dynamics of mahogany...

Planning for and implementing an emerald ash borer-induced forest restoration program in municipal woodlands in Oakville, Ontario

Science.gov (United States)

Peter A. Williams; Candace. Karandiuk

2017-01-01

Oakville is an urban municipality with 846 ha of woodland. Management priorities are to maintain forest health, environmental health, and safety; wood production is a minor objective. The town developed a comprehensive strategy to plan for emerald ash borer (EAB; Agrilus planipennis) induced ash mortality and forest restoration. Oakville has begun...

Estimating pinyon and juniper cover across Utah using NAIP imagery

Directory of Open Access Journals (Sweden)

Darrell B. Roundy

2016-11-01

Full Text Available Expansion of Pinus L. (pinyon and Juniperus L. (juniper (P-J trees into sagebrush (Artemisia L. steppe communities can lead to negative effects on hydrology, loss of wildlife habitat, and a decrease in desirable understory vegetation. Tree reduction treatments are often implemented to mitigate these negative effects. In order to prioritize and effectively plan these treatments, rapid, accurate, and inexpensive methods are needed to estimate tree canopy cover at the landscape scale. We used object based image analysis (OBIA software (Feature AnalystTM for ArcMap 10.1®, ENVI Feature Extraction®, and Trimble eCognition Developer 8.2® to extract tree canopy cover using NAIP (National Agricultural Imagery Program imagery. We then compared our extractions with ground measured tree canopy cover (crown diameter and line point intercept on 309 plots across 44 sites in Utah. Extraction methods did not consistently over- or under-estimate ground measured P-J canopy cover except where tree cover was >45%. Estimates of tree canopy cover using OBIA techniques were strongly correlated with estimates using the crown diameter method (r = 0.93 for ENVI, 0.91 for Feature AnalystTM, and 0.92 for eCognition. Tree cover estimates using OBIA techniques had lower correlations with tree cover measurements using the line-point intercept method (r = 0.85 for ENVI, 0.83 for Feature AnalystTM, and 0.83 for eCognition. All software packages accurately and inexpensively extracted P-J canopy cover from NAIP imagery when the imagery was not blurred, and when P-J cover was not mixed with Amelanchier alnifolia (Utah serviceberry and Quercus gambelii (Gambel’s oak, which had similar spectral values as P-J.

Woodland caribou calf recruitment in relation to calving/post-calving landscape composition

Directory of Open Access Journals (Sweden)

Sara C. McCarthy

2011-04-01

Full Text Available Since the 1990s, Newfoundland’s woodland caribou (Rangifer tarandus caribou population has declined by an estimated 66%. Low calf recruitment has been associated to the decline, possibly triggered by increasing calf predation and/or decreasing resources. To investigate the role of landscape composition in this system, we studied the yearly (2005-2008 calving/post-calving range (CPCR of 104 satellite-collared females belonging to six herds. We mapped nine disturbance factors (e.g. roads, logging, etc, as well as vegetation cover types (e.g. coniferous, deciduous forests, etc, and determined the total area they occupied within CPCRs yearly for each herd. Using an information theoretic approach, we assessed the model that best explained variation in recruitment using these components. Based on corrected Akaike Information Criterion, the model that best explained variation in calf recruitment included total disturbance and deciduous forest area, both showing the expected negative relationship with calf recruitment. Other landscape variables among the models with ΔAICc < 2 were mixed forest, also with a suggested negative relationship, and barrens and wetlands with a significant positive trend. This study highlights the need to minimize total disturbance footprint and account for resulting changes in forest composition within CPCRs during land use planning. Expanding forestry operations and road infrastructure in critical woodland caribou habitat across Canada may additionally contribute to habitat loss via fragmentation. This in turn, may lead to range recession beyond the initial local avoidance footprint. We see the possibility of using calf recruitment models based on landscape parameters, among others, to predict the impact of new industrial developments on calf recruitment.

Land-Use History and Contemporary Management Inform an Ecological Reference Model for Longleaf Pine Woodland Understory Plant Communities.

Energy Technology Data Exchange (ETDEWEB)

Brudvig, Lars A. [Department of Plant Biology, Michigan State University; Orrock, John L. [Department of Zoology, University of Wisconsin; Damschen, Ellen I. [Department of Zoology, University of Wisconsin; et al, et al

2014-01-23

Ecological restoration is frequently guided by reference conditions describing a successfully restored ecosystem; however, the causes and magnitude of ecosystem degradation vary, making simple knowledge of reference conditions insufficient for prioritizing and guiding restoration. Ecological reference models provide further guidance by quantifying reference conditions, as well as conditions at degraded states that deviate from reference conditions. Many reference models remain qualitative, however, limiting their utility. We quantified and evaluated a reference model for southeastern U.S. longleaf pine woodland understory plant communities. We used regression trees to classify 232 longleaf pine woodland sites at three locations along the Atlantic coastal plain based on relationships between understory plant community composition, soils lol(which broadly structure these communities), and factors associated with understory degradation, including fire frequency, agricultural history, and tree basal area. To understand the spatial generality of this model, we classified all sites together. and for each of three study locations separately. Both the regional and location-specific models produced quantifiable degradation gradients–i.e., progressive deviation from conditions at 38 reference sites, based on understory species composition, diversity and total cover, litter depth, and other attributes. Regionally, fire suppression was the most important degrading factor, followed by agricultural history, but at individual locations, agricultural history or tree basal area was most important. At one location, the influence of a degrading factor depended on soil attributes. We suggest that our regional model can help prioritize longleaf pine woodland restoration across our study region; however, due to substantial landscape-to-landscape variation, local management decisions should take into account additional factors (e.g., soil attributes). Our study demonstrates the utility

Mapping and estimating the total living biomass and carbon in low-biomass woodlands using Landsat 8 CDR data

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Belachew Gizachew

2016-06-01

Full Text Available Abstract Background A functional forest carbon measuring, reporting and verification (MRV system to support climate change mitigation policies, such as REDD+, requires estimates of forest biomass carbon, as an input to estimate emissions. A combination of field inventory and remote sensing is expected to provide those data. By linking Landsat 8 and forest inventory data, we (1 developed linear mixed effects models for total living biomass (TLB estimation as a function of spectral variables, (2 developed a 30 m resolution map of the total living carbon (TLC, and (3 estimated the total TLB stock of the study area. Inventory data consisted of tree measurements from 500 plots in 63 clusters in a 15,700 km2 study area, in miombo woodlands of Tanzania. The Landsat 8 data comprised two climate data record images covering the inventory area. Results We found a linear relationship between TLB and Landsat 8 derived spectral variables, and there was no clear evidence of spectral data saturation at higher biomass values. The root-mean-square error of the values predicted by the linear model linking the TLB and the normalized difference vegetation index (NDVI is equal to 44 t/ha (49 % of the mean value. The estimated TLB for the study area was 140 Mt, with a mean TLB density of 81 t/ha, and a 95 % confidence interval of 74–88 t/ha. We mapped the distribution of TLC of the study area using the TLB model, where TLC was estimated at 47 % of TLB. Conclusion The low biomass in the miombo woodlands, and the absence of a spectral data saturation problem suggested that Landsat 8 derived NDVI is suitable auxiliary information for carbon monitoring in the context of REDD+, for low-biomass, open-canopy woodlands.

Woodland carbon code: building an evidence base for the "4 per mil" initiative in land converted to forestry.

Science.gov (United States)

Hannam, Jacqueline; Vanguelova, Elena; West, Vicky

2017-04-01

The Woodland Carbon Code is a voluntary standard for woodland creation projects in the UK. Carbon sequestration resulting from certified projects will contribute directly to the UK's national targets for reducing emissions of greenhouse gases (GHG). Whilst this is concerned primarily with above ground capture there is little empirical evidence of the longer term carbon sequestration potential of soils under this land use change in the UK. We present preliminary results from a resurvey of 20 sites originally sampled as part of the soil survey of England and Wales. It includes soil carbon stocks assessed within the soil profile (up to 1m depth) where sites have been converted to forestry in the last 40 years. The small number of sites (n=20) and high variability in soil type, forest type and original land use prevented detailed analysis between these different factors, but overall there was an increase in carbon concentration in the whole profile, driven primarily by an increase the surface organic layers. For all sites combined there was no significant difference in the C stocks between the two survey periods. The increase in carbon stock in the surface organic horizons tended to be offset by a decrease in the mineral subsoils (specifically in Brown Earth soils) primarily as a result of bulk density changes. There are presently insufficient measured data from a range of UK climate, land-use and soil type conditions to quantify with confidence soil C changes during afforestation. This is partly because of the difficulties of detecting relatively slow changes in spatially heterogeneous soils and also obtaining good examples of sites that have undergone documented land use change. Reviewing results from all ongoing afforestation projects in the UK will provide better quantification of the C sequestration potential of forest soils to be accounted for in the Woodland Carbon Code's overall GHG mitigation potential.

Land-Use History and Contemporary Management Inform an Ecological Reference Model for Longleaf Pine Woodland Understory Plant Communities

Science.gov (United States)

Brudvig, Lars A.; Orrock, John L.; Damschen, Ellen I.; Collins, Cathy D.; Hahn, Philip G.; Mattingly, W. Brett; Veldman, Joseph W.; Walker, Joan L.

2014-01-01

Ecological restoration is frequently guided by reference conditions describing a successfully restored ecosystem; however, the causes and magnitude of ecosystem degradation vary, making simple knowledge of reference conditions insufficient for prioritizing and guiding restoration. Ecological reference models provide further guidance by quantifying reference conditions, as well as conditions at degraded states that deviate from reference conditions. Many reference models remain qualitative, however, limiting their utility. We quantified and evaluated a reference model for southeastern U.S. longleaf pine woodland understory plant communities. We used regression trees to classify 232 longleaf pine woodland sites at three locations along the Atlantic coastal plain based on relationships between understory plant community composition, soils (which broadly structure these communities), and factors associated with understory degradation, including fire frequency, agricultural history, and tree basal area. To understand the spatial generality of this model, we classified all sites together and for each of three study locations separately. Both the regional and location-specific models produced quantifiable degradation gradients–i.e., progressive deviation from conditions at 38 reference sites, based on understory species composition, diversity and total cover, litter depth, and other attributes. Regionally, fire suppression was the most important degrading factor, followed by agricultural history, but at individual locations, agricultural history or tree basal area was most important. At one location, the influence of a degrading factor depended on soil attributes. We suggest that our regional model can help prioritize longleaf pine woodland restoration across our study region; however, due to substantial landscape-to-landscape variation, local management decisions should take into account additional factors (e.g., soil attributes). Our study demonstrates the utility of

Land-use history and contemporary management inform an ecological reference model for longleaf pine woodland understory plant communities.

Directory of Open Access Journals (Sweden)

Lars A Brudvig

Full Text Available Ecological restoration is frequently guided by reference conditions describing a successfully restored ecosystem; however, the causes and magnitude of ecosystem degradation vary, making simple knowledge of reference conditions insufficient for prioritizing and guiding restoration. Ecological reference models provide further guidance by quantifying reference conditions, as well as conditions at degraded states that deviate from reference conditions. Many reference models remain qualitative, however, limiting their utility. We quantified and evaluated a reference model for southeastern U.S. longleaf pine woodland understory plant communities. We used regression trees to classify 232 longleaf pine woodland sites at three locations along the Atlantic coastal plain based on relationships between understory plant community composition, soils (which broadly structure these communities, and factors associated with understory degradation, including fire frequency, agricultural history, and tree basal area. To understand the spatial generality of this model, we classified all sites together and for each of three study locations separately. Both the regional and location-specific models produced quantifiable degradation gradients-i.e., progressive deviation from conditions at 38 reference sites, based on understory species composition, diversity and total cover, litter depth, and other attributes. Regionally, fire suppression was the most important degrading factor, followed by agricultural history, but at individual locations, agricultural history or tree basal area was most important. At one location, the influence of a degrading factor depended on soil attributes. We suggest that our regional model can help prioritize longleaf pine woodland restoration across our study region; however, due to substantial landscape-to-landscape variation, local management decisions should take into account additional factors (e.g., soil attributes. Our study demonstrates

Methods for estimating private forest ownership statistics: revised methods for the USDA Forest Service's National Woodland Owner Survey

Science.gov (United States)

Brenton J. ​Dickinson; Brett J. Butler

2013-01-01

The USDA Forest Service's National Woodland Owner Survey (NWOS) is conducted to better understand the attitudes and behaviors of private forest ownerships, which control more than half of US forestland. Inferences about the populations of interest should be based on theoretically sound estimation procedures. A recent review of the procedures disclosed an error in...

Radiation monitoring of local foodstuffs in some settlements in Belarus located not far from woodlands

International Nuclear Information System (INIS)

Devojno, A.N.; Nesterenko, V.B.; Mukhlaev, A.A.; Troyanovskij, S.V.

2005-01-01

Here are the results of radiation monitoring performed by the local centres for radiation control in some settlements located in radiation contaminated territories not far from woodlands. It is shown that within the decennial period from 1993 to 2003 the Caesium 137 radiation contamination of mushrooms, game and milk from private household makes significant values and do not have the decreasing tendency. It is recommended to use possible radioprotective measures of the population under above stated circumstances. (authors)

Little Smoky Woodland Caribou Calf Survival Enhancement Project

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Kirkby G. Smith

2011-09-01

Full Text Available The Little Smoky woodland caribou (Rangifer tarandus herd is a boreal ecotype located in west central Alberta, Canada. This herd has declined steadily over the past decade and is currently thought to number approximately 80 animals. Factors contributing to the herds' decline appear related to elevated predator-caused mortality rates resulting from industrial caused landscape change. At current rates of decline, the herd is at risk of extirpation. A calf survival enhancement project was initiated in the first half of 2006 as a means of enhancing recruitment while other longer-term approaches were implemented. A total of 10 pregnant females were captured in early March and held in captivity until all calves were at least 3 weeks old. Before release, calves were radiocollared with expandable drop-off collars. Following release, survival of mother and offspring were tracked at intervals until the fall rut. Survival of penned calves was compared to "wild-born" calves at heel of non captive radiocollared females. This approach is compared to other techniques designed to increase recruitment in caribou.

Middle- and upper-Holocene woodland history in central Moravia (Czech Republic) reveals biases of pollen and anthracological analysis

Czech Academy of Sciences Publication Activity Database

Novák, J.; Abraham, V.; Kočár, Petr; Petr, L.; Kočárová, R.; Nováková, K.; Houfková, P.; Jankovská, Vlasta; Vaněček, Z.

2017-01-01

Roč. 27, č. 3 (2017), s. 349-360 ISSN 0959-6836 Grant - others:GA ČR(CZ) GA13-11193S Institutional support: RVO:67985912 ; RVO:67985939 Keywords : woodland history * charcoals * archaeological sites Subject RIV: AC - Archeology, Anthropology, Ethnology; EF - Botanics (BU-J) OBOR OECD: Archaeology; Plant sciences, botany (BU-J) Impact factor: 2.324, year: 2016

Assessment of bird populations in a high quality savanna/woodland: a banding approach

Science.gov (United States)

Wilmore, Sandra L.; Glowacki, Gary A.; Grundel, Ralph

2005-01-01

Between 1999 and 2004, Save the Dunes Conservation Fund's Miller Woods Bird Banding Program monitored migrating and breeding bird populations within a high quality black oak, dry-mesic sand savanna/woodland with ridge and swale topography. The objectives of this program were to collect consistent and reliable demographic and abundance data on the bird populations, to investigate long-term population trends, and to contribute to improved land management decisions at regional and national scales. The technique employed involved capturing birds in mist nets that were deployed for set periods of time at 17 net sites in two banding areas in Miller Woods.

Relationships between bat occupancy and habitat and landscape structure along a savanna, woodland, forest gradient in the Missouri Ozarks

Science.gov (United States)

Clarissa A. Starbuck; Sybill K. Amelon; Frank R. III. Thompson

2015-01-01

Many land-management agencies are restoring savannas and woodlands using prescribed fire and forest thinning, and information is needed on how wildlife species respond to these management activities. Our objectives were to evaluate support for relationships of bat site occupancy with vegetation structure and management and landscape composition and structure across a...

Ecological studies in a Scanian woodland and meadow area, southern Sweden. Ti. Plant biomass, primary production and turnover of organic matter

Energy Technology Data Exchange (ETDEWEB)

Andersson, F

1970-01-01

As a part of an IBP project the productivity of the south Swedish deciduous woodland ecosystems and their secondary successional stages a comparison between the distribution of organic matter in a mixed deciduous woodland dominated by Quercus robur, Tilia cordata, Corylus avellana and Anemone nemorosa and a tall herb meadow with Filipendula ulmaria within the nemoral zone in the southernmost part of Sweden has been made. Estimations of the plant biomass and production in the woodland was made by a dimension analysis applying allometric equations. A total plant biomass of 240 t/ha was found with 201 t/ha and 39 t/ha as above-and below-ground figures respectively. The corresponding figures of the net primary production are 15.6, 13.3 and 2.3 t/ha. A production of 0.77 t/ha is included for the above-ground production of the field layer. The litter fall, fractions less than 50 cm long, during a three year period amounted to 5.28 t/ha with considerable variation between years. Including coarser litter fractions an yearly input to the ground of 6.5 t/ha was found. After estimation of the remaining litter before the leaf fall, 6.1 t/ha, the yearly turnover of the litter layer is calculated to 52%. As the humus fraction amounts to 218 t/ha, the total content of organic matter in the woodland ecosystem thus is 463 t/ha with an almost equal distribution between above-and below-ground portions. In the meadow the distribution of above-and below-ground portions of the organic matter is 1/49, calculated from the following figures: Above-ground biomass 4.7 t/ha, below-ground biomass 13.2 t/ha, surface litter 2.4 t/ha and humus 304 t/ha making the total organic matter of the meadow ecosystem 324 t/ha. The yearly above-ground production is estimated to be 7.2 t/ha and taking this as the yearly litter input to the ground and taking the remaining litter into account a turnover of the litter layer 75% is calculated.

Estimating the non-market costs and benefits of native woodland restoration using the contingent valuation method.

OpenAIRE

MacMillan, Douglas C.; Duff, Elizabeth I.

1998-01-01

The restoration of native forests is an important priority for forestry and conservation organizations in the United Kingdom. The economic case for public sector support for native woodland restoration in the United Kingdom rests almost entirely on the provision of non-market benefits related to wildlife, landscape and recreational opportunities. This paper describes a discrete choice contingent valuation (CV) to estimate the value of the non-market benefits of restoring two native pinewood f...

Effects of competition and herbivory over woody seedling growth in a temperate woodland trump the effects of elevated CO2.

Science.gov (United States)

Collins, L; Boer, M M; de Dios, V Resco; Power, S A; Bendall, E R; Hasegawa, S; Hueso, R Ochoa; Nevado, J Piñeiro; Bradstock, R A

2018-04-27

A trend of increasing woody plant density, or woody thickening, has been observed across grassland and woodland ecosystems globally. It has been proposed that increasing atmospheric [CO 2 ] is a major driver of broad scale woody thickening, though few field-based experiments have tested this hypothesis. Our study utilises a Free Air CO 2 Enrichment experiment to examine the effect of elevated [CO 2 ] (eCO 2 ) on three mechanisms that can cause woody thickening, namely (i) woody plant recruitment, (ii) seedling growth, and (iii) post-disturbance resprouting. The study took place in a eucalypt-dominated temperate grassy woodland. Annual assessments show that juvenile woody plant recruitment occurred over the first 3 years of CO 2 fumigation, though eCO 2 did not affect rates of recruitment. Manipulative experiments were established to examine the effect of eCO 2 on above-ground seedling growth using transplanted Eucalyptus tereticornis (Myrtaceae) and Hakea sericea (Proteaceae) seedlings. There was no positive effect of eCO 2 on biomass of either species following 12 months of exposure to treatments. Lignotubers (i.e., resprouting organs) of harvested E. tereticornis seedlings that were retained in situ for an additional year were used to examine resprouting response. The likelihood of resprouting and biomass of resprouts increased with lignotuber volume, which was not itself affected by eCO 2 . The presence of herbaceous competitors and defoliation by invertebrates and pathogens were found to greatly reduce growth and/or resprouting response of seedlings. Our findings do not support the hypothesis that future increases in atmospheric [CO 2 ] will, by itself, promote woody plant recruitment in eucalypt-dominated temperate grassy woodlands.

Effects of urban density on carbon dioxide exchanges: Observations of dense urban, suburban and woodland areas of southern England.

Science.gov (United States)

Ward, H C; Kotthaus, S; Grimmond, C S B; Bjorkegren, A; Wilkinson, M; Morrison, W T J; Evans, J G; Morison, J I L; Iamarino, M

2015-03-01

Anthropogenic and biogenic controls on the surface-atmosphere exchange of CO2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO2 emissions all year round. Observed CO2 fluxes reflect diurnal traffic patterns (busy throughout the day (urban); rush-hour peaks (suburban)) and vary between working days and non-working days, except at the woodland site. Suburban vegetation offsets some anthropogenic emissions, but 24-h CO2 fluxes are usually positive even during summer. Observations are compared to estimated emissions from simple models and inventories. Annual CO2 exchanges are significantly different between sites, demonstrating the impacts of increasing urban density (and decreasing vegetation fraction) on the CO2 flux to the atmosphere. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Self-thinning dynamics in cork oak woodlands: providing a baseline for managing density

International Nuclear Information System (INIS)

Fonseca, T.; Monteiro, L.; Enes, T.; Cerveira, A.

2017-01-01

Aim of study: The study aims to evaluate the maximum potential stocking level in cork oak (Quercus suber L.) woodlands, using the ecologically-based size-density relationship of the self-thinning law. Area of study: The study area refers to cork oak forests in mainland Portugal, distributed along its 18 districts from north to south. Material and Methods: A dataset with a total of 2181 observations regarding pure cork oak stands was collected from the Portuguese Forest Inventory (NFI) databases and from research plots. The dataset was subjected to two filtering procedures, one more restrictive than the other, to select the stands presenting the higher stocking values. The two resulting subsets, with 116 and 36 observations, from 16 and 10 districts of mainland Portugal, respectively, were then used to assess and describe the allometric relationship between tree number and their mean diameter. Main results: The allometric relationship was analysed and modelled using the log transformed variables. A slightly curvilinear trend was identified. Thus, a straight line and a curve were both fitted for comparison purposes. Goodness-of-fit statistics point out for a good performance when the data is set to the uppermost observed stocking values. A self-thinning line for cork oak was projected from the estimated relationship. Research highlights: The self-thinning model can be used as an ecological approach to develop density guidelines for oak woodlands in a scenario of increasing cork demands. The results indicate that the recommendations being applied in Portugal are far below the maximal potential stocking values for the species. It is therefore of the utmost importance to review the traditional silvicultural guidelines and endorse new ones.

Self-thinning dynamics in cork oak woodlands: providing a baseline for managing density

Energy Technology Data Exchange (ETDEWEB)

Fonseca, T.; Monteiro, L.; Enes, T.; Cerveira, A.

2017-11-01

Aim of study: The study aims to evaluate the maximum potential stocking level in cork oak (Quercus suber L.) woodlands, using the ecologically-based size-density relationship of the self-thinning law. Area of study: The study area refers to cork oak forests in mainland Portugal, distributed along its 18 districts from north to south. Material and Methods: A dataset with a total of 2181 observations regarding pure cork oak stands was collected from the Portuguese Forest Inventory (NFI) databases and from research plots. The dataset was subjected to two filtering procedures, one more restrictive than the other, to select the stands presenting the higher stocking values. The two resulting subsets, with 116 and 36 observations, from 16 and 10 districts of mainland Portugal, respectively, were then used to assess and describe the allometric relationship between tree number and their mean diameter. Main results: The allometric relationship was analysed and modelled using the log transformed variables. A slightly curvilinear trend was identified. Thus, a straight line and a curve were both fitted for comparison purposes. Goodness-of-fit statistics point out for a good performance when the data is set to the uppermost observed stocking values. A self-thinning line for cork oak was projected from the estimated relationship. Research highlights: The self-thinning model can be used as an ecological approach to develop density guidelines for oak woodlands in a scenario of increasing cork demands. The results indicate that the recommendations being applied in Portugal are far below the maximal potential stocking values for the species. It is therefore of the utmost importance to review the traditional silvicultural guidelines and endorse new ones.

Baseline ecological footprint of Sandia National Laboratories, New Mexico.

Energy Technology Data Exchange (ETDEWEB)

Coplen, Amy K.; Mizner, Jack Harry,; Ubechel, Norion M.

2009-01-01

The Ecological Footprint Model is a mechanism for measuring the environmental effects of operations at Sandia National Laboratories in Albuquerque, New Mexico (SNL/NM). This analysis quantifies environmental impact associated with energy use, transportation, waste, land use, and water consumption at SNL/NM for fiscal year 2005 (FY05). Since SNL/NMs total ecological footprint (96,434 gha) is greater than the waste absorption capacity of its landholdings (338 gha), it created an ecological deficit of 96,096 gha. This deficit is equal to 886,470lha, or about 3,423 square miles of Pinyon-Juniper woodlands and desert grassland. 89% of the ecological footprint can be attributed to energy use, indicating that in order to mitigate environmental impact, efforts should be focused on energy efficiency, energy reduction, and the incorporation of additional renewable energy alternatives at SNL/NM.

Assessment of fuelwood resources in acacia woodlands in the Rift Valley of Ethiopia. Towards the development of planning tools for sustainable management

Energy Technology Data Exchange (ETDEWEB)

Eshete, Getachew [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Resource Management and Geomatics

1999-07-01

The subjects addressed in this thesis are the development and description of methods for acquiring information on the state and change and for forecasting the potential future state in the acacia woodlands in the Rift Valley of Ethiopia. Since issues of data collection and prediction are core components of planning, it is believed that the methods developed and described will be useful in future integrated planning tools for the sustainable management of acacia woodlands. The thesis is composed of five studies that are reported separately. In the first study, the focus was on describing the population structure and regeneration of the main tree species in the study area. In the second study, biomass functions suitable for application in multiphase inventory designs were developed. In the third study, the application of satellite image data in the assessment of the acacia woodlands, partly using the functions developed in the second study, is demonstrated. Different methods were applied for assessing the biomass and crown closure of acacias in the study area. Results using the different estimators revealed that the average woody biomass is in the range of 10 to 20 tons ha{sup -1} and the crown cover was reduced by approximately 7 to 12 %, between the years 1972 and 1995, in the study area. Furthermore, the advantages and difficulties of using different designs were investigated. Maps indicating the patterns of the state and change of the woodlands in relation to the landscape features of the study site were also produced. In the fourth study, the aim was to find out whether or not tree-rings in acacias can be used as indicators of growth periodicity. The results indicated that the acacias form one ring per year in the study area, although this was not the case in surrounding, more humid, areas. Following this outcome, in the fifth study, single tree growth functions were developed and were utilized to project the biomass growth of acacias in the study area. One area

Preliminary assessment of habitat characteristics of woodland caribou calving areas in the Claybelt region of Québec and Ontario, Canada

Directory of Open Access Journals (Sweden)

Émilie Lantin

2003-04-01

Full Text Available Woodland caribou (Rangifer tarandus caribou require a diversity of forested habitats over large areas and may thus be particularly affected by the large-scale changes in the composition and age-class distribution of forest landscapes induced by the northern expansion of forest management. In this study we examine habitat characteristics associated to the use of calving areas by woodland caribou females and calves at different spatial scales. Thirty females were captured and collared with Argos satellite transmitters that allowed to locate 14 calving areas. Field surveys were conducted at each of these areas to measure the landscape composition of forest cover types and local vegetation characteristics that are used for both forage conditions and protection cover. At the scale of the calving area, univariate comparisons of the amount of forest cover types between sites with and without calves showed that the presence of calves was associated to mature black spruce forest with a high percent cover of terrestrial lichens. Within calving grounds, univariate comparisons showed that vegetation features like ericaceans and terrestrial lichens, that are important food resources for lactating females, were more abundant in calving areas where females were seen with a calf in mid-July than in areas where females were seen alone. The protection of the vegetation cover against predators was however similar between calving areas with or with¬out a calf. Logistic regression results also indicated that vegetation characteristics associated to forage conditions were positively associated to calf presence on calving grounds. Our results suggest that foraging conditions should be given more attention in analyses on habitat requirements of woodland caribou.

Habitat Restoration as a Key Conservation Lever for Woodland Caribou: A review of restoration programs and key learnings from Alberta

Directory of Open Access Journals (Sweden)

Paula Bentham

2015-12-01

Full Text Available The Recovery Strategy for the Woodland Caribou (Rangifer tarandus caribou, Boreal Population in Canada (EC, 2012, identifies coordinated actions to reclaim woodland caribou habitat as a key step to meeting current and future caribou population objectives. Actions include restoring industrial landscape features such as roads, seismic lines, pipelines, cut-lines, and cleared areas in an effort to reduce landscape fragmentation and the changes in caribou population dynamics associated with changing predator-prey dynamics in highly fragmented landscapes. Reliance on habitat restoration as a recovery action within the federal recovery strategy is high, considering all Alberta populations have less than 65% undisturbed habitat, which is identified in the recovery strategy as a threshold providing a 60% chance that a local population will be self-sustaining. Alberta’s Provincial Woodland Caribou Policy also identifies habitat restoration as a critical component of long-term caribou habitat management. We review and discuss the history of caribou habitat restoration programs in Alberta and present outcomes and highlights of a caribou habitat restoration workshop attended by over 80 representatives from oil and gas, forestry, provincial and federal regulators, academia and consulting who have worked on restoration programs. Restoration initiatives in Alberta began in 2001 and have generally focused on construction methods, revegetation treatments, access control programs, and limiting plant species favourable to alternate prey. Specific treatments include tree planting initiatives, coarse woody debris management along linear features, and efforts for multi-company and multi-stakeholder coordinated habitat restoration on caribou range. Lessons learned from these programs have been incorporated into large scale habitat restoration projects near Grande Prairie, Cold Lake, and Fort McMurray. A key outcome of our review is the opportunity to provide a

Estructura y estado de conservación de los bosques de Prosopis flexuosa D.C. (Fabaceae, subfamilia: Mimosoideae en el noreste de Mendoza (Argentina Structure and conservative condition of the Prosopis flexuosa D.C. (Fabaceae, subfamily: Mimosoideae woodlands in northeast Mendoza (Argentina

Directory of Open Access Journals (Sweden)

JUAN AGUSTÍN ALVAREZ

2006-03-01

allowed to find out about the population structure of the Prosopis flexuosa woodlands of the northeast of Mendoza, as well as their sanitary conditions and the management potential. A total of 1,471 Prosopis individuals were sampled in the four most representative woodlands units. The total Prosopis density was as follows: P. flexuosa semi-closed woodland with Atriplex lampa and Lycium tenuispinosum in valleys in-between dunes (Woodland 1: 181 trees ha-1; P. flexuosa open woodland with Trichomaria usillo and Suaeda divaricata in the undulations (Woodland 2: 155 trees ha-1; P. flexuosa open woodland with T. usillo (Woodland 3: 233 trees ha-1, and P. flexuosa open woodland with A. lampa in soft undulations (Woodland 4: 215 trees ha-1. The principal components analysis on the diametric structure grouped the sites surveyed in the different woodland units as per the proportion of individuals with larger basal diameter. The sites from Woodland 1 (larger proportion of big trees, were separated from the sites with a higher proportion of small trees (Woodland 2 and 4. Due to the Prosopis growth habit, the quantity of wood products from these forests is low. Besides P. flexuosa presents in the area a high percentage of individuals with more than two stems, the tree shape is generally decumbent and the bole height is less than a meter. Therefore, the possible use should be done at local scale, taking into account the inclusion of other complementary activities

Decreased summer drought affects plant productivity and soil carbon dynamics in Mediterranean woodland

Science.gov (United States)

Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

2011-06-01

Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. The throughfall manipulation experiment started in 2004 and we report data up to the 2009 growing season. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 50 % and 220 %, respectively, as compared to control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction of precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodland. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long term soil C stocks.

Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon

Science.gov (United States)

Berner, L. T.; Law, B. E.

2015-11-01

Severe droughts occurred in the western United States during recent decades, and continued human greenhouse gas emissions are expected to exacerbate warming and drying in this region. We investigated the role of water availability in shaping forest carbon cycling and morphological traits in the eastern Cascade Mountains, Oregon, focusing on the transition from low-elevation, dry western juniper (Juniperus occidentalis) woodlands to higher-elevation, wetter ponderosa pine (Pinus ponderosa) and grand fir (Abies grandis) forests. We examined 12 sites in mature forests that spanned a 1300 mm yr-1 gradient in mean growing-year climate moisture index (CMIgy ), computed annually (1964 to 2013) as monthly precipitation minus reference evapotranspiration and summed October to September. Maximum leaf area, annual aboveground productivity, and aboveground live tree biomass increased with CMIgy (r2 = 0.67-0.88, P gy (r2 = 0.53, P gy and extensive insect outbreak. Traits of stress-tolerant juniper included short stature, high wood density for cavitation resistance, and high investment in water transport relative to leaf area. Species occupying wetter areas invested more resources in height growth in response to competition for light relative to investment in hydraulic architecture. Consequently, maximum tree height, leaf area : sapwood area ratio, and stem wood density were all correlated with CMIgy . The tight coupling of forest carbon cycling and species traits with water availability suggests that warmer and drier conditions projected for the 21st century could have significant biogeochemical, ecological, and social consequences in the Pacific Northwest.

Decreased summer drought affects plant productivity and soil carbon dynamics in a Mediterranean woodland

Science.gov (United States)

Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

2011-09-01

Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.

Evaluation of the WEPP hillslope model on stable and eroding semiarid woodlands

International Nuclear Information System (INIS)

Wilcox, B.P.; Simanton, J.R.

1995-01-01

In this paper, we evaluate runoff and erosion prediction by the WEPP hillslope model for two pinyon-juniper sites in New Mexico: one has a low erosion rate (stable site) and the other (unstable site) is eroding at very rapid rates (as a result of landuse and climatic perturbations over the last century). Runoff and erosion measurements were made at plot and hillslope scales at both sites. WEPP was evaluated using both rainfall simulation and natural rainfall data. Rainfall simulation was performed on both vegetated and bare plots. Parameter values used were developed from rainfall simulation experiments and site characteristics. In general, runoff and erosion were underpredicted at both sites but to a much larger degree at the unstable site. On the unstable site predictions were much improved when we used hydraulic conductivity (Ke) derived from the bare plot rainfall simulation. Also of importance, at the unstable site we observed a large increase in erosion as scale increased from the plot to the hillslope as a result of a well developed channel network. These results are preliminary, in that only a few storms were evaluated, however, they do suggest some important strategies for predicting the impact of reduced vegetation cover to erosion in semiarid landscapes

A Cooperative Industry - Government Woodland Caribou Research Program in Northeastern Alberta

Directory of Open Access Journals (Sweden)

Blair Rippin

1996-01-01

Full Text Available Rapid development of large scale logging and increasingly intensive petroleum exploration and development in northeastern Alberta prompted the establishment of a cooperative research program to investigate various aspects of woodland caribou (Rangifer tarandus caribou biology. The ultimate goal of the program is to develop an effective plan that will ensure the long term survival of caribou while allowing for renewable and non-renewable resource development. There are three parts to the program. Part I began early in 1991 and makes use of conventional radio telemetry as a means of recording various parameters of general caribou biology. The study area encompasses approximately 4000 km2 of low relief, boreal mixedwood forest. Preliminary results from 2500 radio locations (involving 50 individuals indicate that woodland caribou inhabiting the study area are non-migratory and are strongly associated with some of the more scarce peatland forest types present in the area. Investigations to document the basic biology and ecology will continue for another two years. Part II began in early 1993 as a part of a two-year investigation into the disturbance effects of petroleum exploration and development on caribou movements and behaviour. One objective of this study is to develop a predictive model useful in determining the cumulative effects of varying intensities of disturbance on caribou. Part III began in early 1994 with a proposed three-year investigation to determine the mechanism of spatial and temporal separation of caribou and moose in the study area. These relationships may indicate the means by which caribou minimize the impact of wolf predation on their populations in northeastern Alberta. Results will be applied to industrial land use and specifically to large scale forest harvesting planned for the area. The research program is supported through cooperative funding contributed by 24 petroleum companies, 1 forest company, 2 peat companies and

Role of microbes associated with organic and inorganic substrates in phosphorus spiralling in a woodland stream

International Nuclear Information System (INIS)

Elwood, J.W.; Newbold, J.D.; O'Neill, R.V.; Stark, R.W.; Singley, P.T.

1980-01-01

Laboratory and field experiments were conducted to determine if nutrient spiralling is primarily a biological process. The experiments were conducted to examine the role of microbial uptake and abiotic sorption onto organic and inorganic substrates in the uptake of PO 4 -P in Walker Branch, a small, first-order woodland stream in east Tennessee, to estimate the total, microbial, and adsorptive pool sizes of exchangeable phosphorus associated with five particulate organic matter from this stream, and to measure the turnover rate of PO 4 -P by live and sterile inorganic substrates in Walker Branch

Dual extraction of essential oil and podophyllotoxin from creeping juniper (Juniperus horizontalis.

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Charles L Cantrell

Full Text Available Juniperus horizontalis Moench (Family Cupressaceae, commonly called creeping juniper, is a widely distributed species in the United States and much of Canada. It is potentially a source for two important chemical products, the anticancer drug synthetic precursor, podophyllotoxin and essential oils. The objectives of this study were to ascertain the likelihood of utilizing J. horizontalis needles for the simultaneous production of both (--podophyllotoxin and essential oil components and to determine the optimum distillation time (DT needed for the production of essential oil containing a specific ratio of constituents. Eleven different distillation times were tested in this study: 20, 40, 80, 160, 180, 240, 480, 600, 720, 840, and 960 min. Total essential oil content increased with increasing distillation time from a minimum of 0.023% at 20 min to a maximum of 1.098% at 960 min. The major constituents present in the oil were alpha-pinene, sabinene, and limonene. The percent concentration of sabinene in the essential oil varied from a high of 46.6% at 80 min to a low of 30.2% at 960 min, that of limonene changed very little as a result of distillation time and remained near 30% for all distillation times, whereas the concentration of alpha-pinene was 9.6% at 20 min DT and decreased to 4.2% at 960 min. Post distillation analysis of needles revealed elevated amounts of (--podophyllotoxin remaining in the tissue varied in the amount of podophyllotoxin present, from a low of 0.281% to a high of 0.364% as compared to undistilled needles which gave 0.217% podophyllotoxin. As a result of this study, specific essential oil components can now be targeted in J. horizontalis by varying the distillation time. Furthermore, needles can be successfully utilized as a source of both essential oil and podophyllotoxin, consecutively.

Decreased summer drought affects plant productivity and soil carbon dynamics in a Mediterranean woodland

Directory of Open Access Journals (Sweden)

M. F. Cotrufo

2011-09-01

Full Text Available Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR. Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.

Volume and aboveground biomass models for dry Miombo woodland in Tanzania

DEFF Research Database (Denmark)

Mwakalukwa, Ezekiel Edward; Meilby, Henrik; Treue, Thorsten

2014-01-01

Tools to accurately estimate tree volume and biomass are scarce for most forest types in East Africa, including Tanzania. Based on a sample of 142 trees and 57 shrubs from a 6,065 ha area of dry miombo woodland in Iringa rural district in Tanzania, regression models were developed for volume...... and biomass of three important species, Brachystegia spiciformis Benth. (n=40), Combretum molle G. Don (n=41), and Dalbergia arbutifolia Baker (n=37) separately, and for broader samples of trees (28 species, n=72), shrubs (16 species, n=31), and trees and shrubs combined (44 species, n=104). Applied...... of the predictions tended to increase from general to species-specific models. Except for a few volume and biomass models developed for shrubs, all models had R2 values of 96–99%. Thus, the models appear robust and should be applicable to forests with similar site conditions, species, and diameter ranges....

ISOTHECIUM MYOSUROIDES AND THUIDIUM TAMARISCINUM MOSSES AS BIOINDICATORS OF NITROGEN AND HEAVY METAL DEPOSITION IN ATLANTIC OAK WOODLANDS

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K. Wilkins

2015-04-01

Full Text Available Moss tissue chemistry is widely used as a bioindicator of atmospheric deposition. The objective of this study was to compare the tissue chemistry of two moss species in Irish Atlantic oak woodlands, Isothecium myosuroides [Im] and Thuidium tamariscinum [Tt], and to determine their relationship to indices of atmospheric deposition. Moss species were collected from twenty-two woodland sites during April 2013 and analysed for nitrogen, sulphur, and eleven heavy metals. Nitrogen content was significantly correlated between species (rs = 0.84, but their mean values (Im = 1.23%, Tt = 1.34% were significantly different. A simple linear regression suggested that nitrogen content was significantly related to atmospheric ammonia (R2 = 0.67 [Im], R2 = 0.65 [Tt] and total nitrogen deposition (R2 = 0.57 [Im], R2 = 0.54 [Tt]. Many heavy metals had significant interspecies correlations (Al, V, Ni, Cu, Zn, As, Sb, Pb; rs = 0.46−0.77. A few metals (As, Sb and Pb were positively correlated with easting and northing for both species, which may suggest transboundary or national industrial emissions sources. The results suggest that both species could be used as bioindicators of deposition for nitrogen and some heavy metals, although further study of the relationship between tissue concentrations and atmospheric deposition is warranted. Furthermore, interspecies calibration is required to use both species in conjunction.

Effects of urban density on carbon dioxide exchanges: observations of dense urban, suburban and woodland areas of southern England

OpenAIRE

Ward, H.C.; Kotthaus, S.; Grimmond, C.S.B.; Bjorkegren, A.; Wilkinson, M.; Morrison, W.T.J.; Evans, J.G.; Morison, J.I.L.; Iamarino, M.

2015-01-01

Anthropogenic and biogenic controls on the surface-atmosphere exchange of CO2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO2 emissions all year round. Observed CO2 fluxes ...

PESFOR-W: Improving the design and environmental effectiveness of woodlands for water Payments for Ecosystem Services

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Gregory Valatin

2017-05-01

Full Text Available The EU Water Framework Directive aims to ensure restoration of Europe’s water bodies to “good ecological status” by 2027. Many Member States will struggle to meet this target, with around half of EU river catchments currently reporting below standard water quality. Diffuse pollution from agriculture represents a major pressure, affecting over 90% of river basins. Accumulating evidence shows that recent improvements to agricultural practices are benefiting water quality but in many cases will be insufficient to achieve WFD objectives. There is growing support for land use change to help bridge the gap, with a particular focus on targeted tree planting to intercept and reduce the delivery of diffuse pollutants to water. This form of integrated catchment management offers multiple benefits to society but a significant cost to landowners and managers. New economic instruments, in combination with spatial targeting, need to be developed to ensure cost effective solutions – including tree planting for water benefits - are realised. Payments for Ecosystem Services (PES are flexible, incentive-based mechanisms that could play an important role in promoting land use change to deliver water quality targets. The PESFOR-W COST Action will consolidate learning from existing woodlands for water PES schemes in Europe and help standardize approaches to evaluating the environmental effectiveness and cost-effectiveness of woodland measures. It will also create a European network through which PES schemes can be facilitated, extended and improved, for example by incorporating other ecosystem services linking with aims of the wider forests-carbon policy nexus.

Understorey productivity in temperate grassy woodland responds to soil water availability but not to elevated [CO2 ].

Science.gov (United States)

Collins, Luke; Bradstock, Ross A; Resco de Dios, Victor; Duursma, Remko A; Velasco, Sabrina; Boer, Matthias M

2018-06-01

Rising atmospheric [CO 2 ] and associated climate change are expected to modify primary productivity across a range of ecosystems globally. Increasing aridity is predicted to reduce grassland productivity, although rising [CO 2 ] and associated increases in plant water use efficiency may partially offset the effect of drying on growth. Difficulties arise in predicting the direction and magnitude of future changes in ecosystem productivity, due to limited field experimentation investigating climate and CO 2 interactions. We use repeat near-surface digital photography to quantify the effects of water availability and experimentally manipulated elevated [CO 2 ] (eCO 2 ) on understorey live foliage cover and biomass over three growing seasons in a temperate grassy woodland in south-eastern Australia. We hypothesised that (i) understorey herbaceous productivity is dependent upon soil water availability, and (ii) that eCO 2 will increase productivity, with greatest stimulation occurring under conditions of low water availability. Soil volumetric water content (VWC) determined foliage cover and growth rates over the length of the growing season (August to March), with low VWC (productivity. However, eCO 2 did not increase herbaceous cover and biomass over the duration of the experiment, or mitigate the effects of low water availability on understorey growth rates and cover. Our findings suggest that projected increases in aridity in temperate woodlands are likely to lead to reduced understorey productivity, with little scope for eCO 2 to offset these changes. © 2018 John Wiley & Sons Ltd.

Impact of a prescribed fire on soil water repellency in a Banksia woodland (Western Australia)

Science.gov (United States)

Muñoz-Rojas, Miriam; Miller, Ben; Tangney, Ryan; Miller, Russell; González-Pérez, José A.; Jiménez-Morillo, Nicasio T.; Zavala, Lorena M.; Jordán, Antonio

2016-04-01

INTRODUCTION The Swan Coastal plain of Western Australia is dominated by fire-prone banksia woodland (Burrows and McCaw, 1990). In these areas, prescription burning is often used to reduce the risk of wildfires, by reducing available fuels (Boer et al., 2009). Little research has been conducted on the effects of prescription burning on Banksia woodlands, and, in particular, information on the impacts on soil properties and soil water repellency (SWR) is scarce. Here, we have studied the impact of fire on SWR in a Banksia woodland and monitored its evolution in the medium-term. It is expected that results are useful for management and restoration of fire-affected Banksia woodlands. METHODS An experimental fire was conducted on May 7th 2015 in Kings Park, Perth, Western Australia. The fire affected an area of 6 ha of mixed Banksia/Allocasuarina woodland under moderate fire intensity. At the time of ignition, the wind speed below the canopy was 1.2 km/h. During the prescribed burning, air temperatures were on average 20 ± 1 °C and relative humidity ranged between 45 and 55% (measured using a Kestrel portable weather station). Fuel moisture averaged 11.8% (measured using Wiltronics moisture meter) and soil moisture at 1 cm deep ranged from 0.1% to 8.6% (measured with a PR2 soil profile probe attached to a HH2 data logger). Temperatures greater than 120 °C were measured 1 cm below the soil surface using iButton temperature sensors. SWR was measured under lab conditions in oven-dry samples (48 h, 105 °C) with the water drop penetration time (WDPT) test. Soil microbial activity was determined with the 1-day CO2 test that is based on the measurement of the CO2 burst produced after moistening dry soil (Muñoz-Rojas et al., 2016). PRELIMINARY RESULTS AND DISCUSSION SWR was severe in the control (mean WDPT = 2608 s) and pre-burned areas (2722 s). One week after the prescribed fire, persistence of soil water repellency remained stable in the burned area (2402 s). In

Cone and seed traits of two Juniperus species influence roles of frugivores and scatter-hoarding rodents as seed dispersal agents

Science.gov (United States)

Dimitri, Lindsay A.; Longland, William S.; Vander Wall, Stephen B.

2017-11-01

Seed dispersal in Juniperus is generally attributed to frugivores that consume the berry-like female cones. Some juniper cones are fleshy and resinous such as those of western juniper (Juniperus occidentalis), while others are dry and leathery such as those of Utah juniper (J. osteosperma). Rodents have been recorded harvesting Juniperus seeds and cones but are mostly considered seed predators. Our study sought to determine if rodents play a role in dispersal of western and Utah juniper seeds. We documented rodent harvest of cones and seeds of the locally-occurring juniper species and the alternate (non-local) juniper species in removal experiments at a western juniper site in northeastern California and a Utah juniper site in western Nevada. Characteristics of western and Utah juniper cones appeared to influence removal, as cones from the local juniper species were preferred at both sites. Conversely, removal of local and non-local seeds was similar. Piñon mice (Peromyscus truei) were responsible for most removal of cones and seeds at both sites. We used radioactively labeled seeds to follow seed fate and found many of these seeds in scattered caches (western juniper: 415 seeds in 82 caches, 63.0% of seeds found; Utah juniper: 458 seeds in 127 caches, 39.5% of seeds found) most of which were attributed to piñon mice. We found little evidence of frugivores dispersing Utah juniper seeds, thus scatter-hoarding rodents appear to be the main dispersal agents. Western juniper cones were eaten by frugivores, and scatter-hoarding is a complimentary or secondary form of seed dispersal. Our results support the notion that Utah juniper has adapted to xeric environments by conserving water through the loss of fleshy fruits that attract frugivores and instead relies on scatter-hoarding rodents as effective dispersal agents.

Leaf Litter Decomposition and Nutrient Dynamics in Woodland and Wetland Conditions along a Forest to Wetland Hillslope

OpenAIRE

Qiu, Song; McComb, Arthur J.; Bell, Richard W.

2012-01-01

Leaf litters of jarrah (Eucalyptus marginata Donn ex Sm.) and banksia (Banksia menziesii R. Br.) were decomposed at woodland and wetland conditions for two years to test site influence on the rates of decomposition. Weight loss was rapid in early rains but slowed substantially in the following months, resulting in 2/3 to 1/2 weights remaining after two years of field exposure. Litter weight loss was well described by a two-substrate quality decay model (R2=0.97−0.99), and the half-lives were ...

Comment on: Shukla, M.K. et al., 2006: Physical and chemical properties of soils under some pinon-juniper-oak canopies in a semi-arid ecosystem in New Mexico

DEFF Research Database (Denmark)

Mollerup, Mikkel; Jensen, Jens Raunsø

2008-01-01

The paper by Shukla et al. [2006. Physical and chemical properties of soils under some pinon-juniper-oak canopies in an semi-arid ecosystem in New Mexico. Journal of Arid Environment 66, 673-685] treats interesting topics of sustainability of different ecosystems and their water availability....... However, the physical-based infiltration theories by Green and Ampt [1911. Studies on soil physics, I, flow of air and water through soils. Journal of Agricultural Science 4, 1-24] and Philip [1957. The theory of infiltration: 1. The infiltration equation and its solution. Soil Science 83, 345-357] seems...... to be applied without necessary reflections. The actual analysis can have resulted in coefficients without their original physical significance...

Stereo photo series for quantifying natural fuels.Volume XIII: grasslands, shrublands, oak-bay woodlands, and eucalyptus forests in the East Bay of California.

Science.gov (United States)

Clinton S. Wright; Robert E. Vihnanek

2014-01-01

Four series of photographs display a range of natural conditions and fuel loadings for grassland, shrubland, oak-bay woodland, and eucalyptus forest ecosystems on the eastern slopes of the San Francisco Bay area of California. Each group of photos includes inventory information summarizing vegetation composition, structure, and loading; woody material loading and...

Conversion of woodlands changes soil related ecosystem services in Subsaharan Africa

Science.gov (United States)

Groengroeft, Alexander; Landschreiber, Lars; Luther-Mosebach, Jona; Masamba, Wellington; Zimmermann, Ibo; Eschenbach, Annette

2015-04-01

In remote areas of Subsaharan Africa, growing population, changes in consumption patterns and increasing global influences are leading to a strong pressure on the land resources. Smallholders convert woodlands by fire, grazing and clearing in different intensities thus changing soil properties and their ecosystem functioning. As the extraction of ecosystem services forms the basis of local wellbeing for many communities, the role of soils in providing ecosystem services is of high importance. Since 2010, "The Future Okavango" project investigates the quantification of ecosystem functions and services at four core research sites along the Okavango river basin (Angola, Namibia, Botswana, see http://www.future-okavango.org/). These research sites have an extent of 100 km2 each. Within our subproject the soil functions underlying ecosystem services are studied: The amount and spatial variation of soil nutrient reserves in woodland and their changes by land use activities, the water storage function as a basis for plant growth, and their effect on groundwater recharge and the carbon storage function. The scientific framework consists of four major parts including soil survey and mapping, lab analysis, field measurements and modeling approaches on different scales. A detailed soil survey leads to a measure of the spatial distribution, extent and heterogeneity of soil types for each research site. For generalization purposes, geomorphological and pedological characteristics are merged to derive landscape units. These landscape units have been overlaid by recent land use types to stratify the research site for subsequent soil sampling. On the basis of field and laboratory analysis, spatial distribution of soil properties as well as boundaries between neighboring landscape units are derived. The parameters analysed describe properties according to grain size distribution, organic carbon content, saturated and unsaturated hydraulic conductivity as well as pore space

Synopsis: the role of prescribed burning in regenerating Quercus macrocarpa and associated woody plants in stringer woodlands in the Black Hills, South Dakota

Science.gov (United States)

Carolyn Hull Sieg; Henry A. Wright

1998-01-01

Poor tree reproduction, sparse shrub cover, and increasing amounts of exotic species such as Kentucky bluegrass (Poa pratensis) are common problems in woody draws in the Northern Great Plains. Although the historic role of fire in maintaining woody draws is unclear, it is likely that these woodlands burned periodically, especially in dry years on hot...

An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks.

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Emily Silver Huff

Full Text Available Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner's management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of 'harvest readiness' and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking. Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.

Assessing the Recreation Value of Urban Woodland Using the Ecosystem Service Approach in Two Forests in the Munich Metropolitan Region

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Gerd Lupp

2016-11-01

Full Text Available Recreation is considered an important ecosystem services (ES in urban woodlands and puts pressure on other ES. Visitor management strategies can be tools to safeguard biodiversity and ES. On-site data are necessary to evaluate the demand for outdoor recreation opportunities in urban woodlands, but also for providing more reliable values for monetization as a basis for multifunctional forest management, and for raising awareness for the importance of urban proximate forests. Such information can also be used for the assessment and monetization of socio-cultural ES, and hence, contribute to developing market-based mechanisms or to promoting these ES. In our paper, we demonstrate methods to describe recreational demand by collecting data from interviews and using camera traps in two forests in the north of Munich for visitor counting. Visitor numbers in the forests were much greater than rough estimations; visitors also had quite long travelling distances to the forests. Jogging or Nordic walking were proven to be important recreational activities. In some of the monitored locations, almost half of the recreationists carried out these sports. Depending on the method chosen, the calculative monetary value of recreation reached up to 15,440 Euro per hectare per year.

Food habits of rodents inhabiting arid and semi-arid ecosystems of central New Mexico

Science.gov (United States)

Hope, Andrew G.; Parmenter, Robert R.

2007-01-01

In this study, we describe seasonal dietary composition for 15 species of rodents collected in all major habitats on the Sevilleta National Wildlife Refuge (Socorro County) in central New Mexico. A comprehensive literature review of food habits for these species from throughout their distribution also is provided. We collected rodents in the field during winter, spring and late summer in 1998 from six communities: riparian cottonwood forest; piñon-juniper woodland; juniper-oak savanna; mesquite savanna; short-grass steppe; and Chihuahuan Desert scrubland. Rodents included Spermophilus spilosoma (Spotted Ground Squirrel), Perognathus flavescens (Plains Pocket Mouse), Perognathus flavus (Silky Pocket Mouse), Dipodomys merriami (Merriam’s Kangaroo Rat), Dipodomys ordii (Ord’s Kangaroo Rat), Dipodomys spectabilis (Banner-tailed Kangaroo Rat), Reithrodontomys megalotis (Western Harvest Mouse), Peromyscus boylii (Brush Mouse), Peromyscus eremicus (Cactus Mouse), Peromyscus leucopus (White-footed Mouse), Peromyscus truei (Piñon Mouse), Onychomys arenicola (Mearn’s Grasshopper Mouse), Onychomys leucogaster (Northern Grasshopper Mouse), Neotoma albigula/leucodon (White-throated Woodrats), and Neotoma micropus (Southern Plains Woodrat). We collected stomach contents of all species, and cheek-pouch contents of heteromyids, and quantified them in the laboratory. We determined seasonal diets in each habitat by calculating mean percentage volumes of seeds, arthropods and green vegetation (plant leaves and stems) for each species of rodent. Seeds consumed by each rodent were identified to genus, and often species, and quantified by frequency counts. Comparisons of diets between and among species of rodents, seasons, and ecosystems were also examined. We provide an appendix of all plant taxa documented.

Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey

Science.gov (United States)

Correia, A. C.; Costa-e-Silva, F.; Dubbert, M.; Piayda, A.; Pereira, J. S.

2016-10-01

Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity? We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP). The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation. Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can

Variability in carbon dioxide fluxes for dense urban, suburban and woodland environments in southern England

Science.gov (United States)

Ward, Helen; Kotthaus, Simone; Grimmond, C. Sue; Bjorkegren, Alex; Wilkinson, Matt; Morrison, Will; Evans, Jon; Morison, James; Christen, Andreas

2014-05-01

The net exchange of carbon dioxide between the surface and atmosphere can be measured using the eddy covariance technique. Fluxes from a dense urban environment (central London), a suburban landscape (Swindon) and a woodland ecosystem (Alice Holt) are compared. All sites are located in southern England and experience similar climatic and meteorological conditions, yet have very different land cover. The signatures of anthropogenic and biogenic processes are explored at various (daily, seasonal and annual) timescales. Particular emphasis is placed on identifying the mixture of controls that determine the flux. In summer, there are clear similarities between the suburban and woodland sites, as the diurnal behaviour is dominated by photosynthetic uptake. In winter, however, vegetation is largely dormant and human activity determines the pattern of fluxes at the urban and suburban sites. Emissions from building heating augment the net release of carbon dioxide in cold months. Road use is a major contributor to the total emissions, and the diurnal cycle in the observed fluxes reflects this: in central London roads are busy throughout the day, whereas in Swindon a double-peaked rush-hour signal is evident. The net exchange of carbon dioxide is estimated for each site and set in context with other studies around the world. Central London has the smallest proportion of vegetation and largest emissions amongst study sites in the literature to date. Although Swindon's appreciable vegetation fraction helps to offset the anthropogenic emissions, even in summertime the 24h total flux is usually positive, indicating carbon release. Comparison of these three sites in a similar region demonstrates the effects of increasing urban density and changing land use on the atmosphere. Findings are relevant in terms of characterising the behaviour of urban surfaces and for quantifying the impact of anthropogenic activities.

Farms, pastures and woodlands: the fine-scale distribution of Palearctic Culicoides spp. biting midges along an agro-ecological gradient.

Science.gov (United States)

Rigot, T; Drubbel, M Vercauteren; Delécolle, J-C; Gilbert, M

2013-03-01

The spatial epidemiology of Bluetongue virus (BTV) at the landscape level relates to the fine-scale distribution and dispersal capacities of its vectors, midges belonging to the genus Culicoides Latreille (Diptera: Ceratopogonidae). Although many previous researches have carried out Culicoides sampling on farms, little is known of the fine-scale distribution of Culicoides in the landscape immediately surrounding farms. The aim of this study was to gain a better understanding of Culicoides populations at increasing distances from typical dairy farms in north-west Europe, through the use of eight Onderstepoort-type black-light traps positioned along linear transects departing from farms, going through pastures and entering woodlands. A total of 16 902 Culicoides were collected in autumn 2008 and spring 2009. The majority were females, of which more than 97% were recognized as potential vectors. In pastures, we found decreasing numbers of female Culicoides as a function of the distance to the farm. This pattern was modelled by leptokurtic models, with parameters depending on season and species. By contrast, the low number of male Culicoides caught were homogeneously distributed along the transects. When transects entered woodlands, we found a higher abundance of Culicoides than expected considering the distance of the sampling sites to the farm, although this varied according to species. © 2012 The Authors. Medical and Veterinary Entomology © 2012 The Royal Entomological Society.

Effects of urban density on carbon dioxide exchanges: Observations of dense urban, suburban and woodland areas of southern England

International Nuclear Information System (INIS)

Ward, H.C.; Kotthaus, S.; Grimmond, C.S.B.; Bjorkegren, A.; Wilkinson, M.; Morrison, W.T.J.; Evans, J.G.; Morison, J.I.L.; Iamarino, M.

2015-01-01

Anthropogenic and biogenic controls on the surface–atmosphere exchange of CO 2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO 2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO 2 emissions all year round. Observed CO 2 fluxes reflect diurnal traffic patterns (busy throughout the day (urban); rush-hour peaks (suburban)) and vary between working days and non-working days, except at the woodland site. Suburban vegetation offsets some anthropogenic emissions, but 24-h CO 2 fluxes are usually positive even during summer. Observations are compared to estimated emissions from simple models and inventories. Annual CO 2 exchanges are significantly different between sites, demonstrating the impacts of increasing urban density (and decreasing vegetation fraction) on the CO 2 flux to the atmosphere. - Highlights: • Multi-seasonal comparison of contemporaneous CO 2 fluxes over contrasting land cover. • Signatures of anthropogenic and biogenic processes explored at various timescales. • Observations reveal relative magnitude of anthropogenic emissions. • CO 2 fluxes related to surface controls, strongly dependent on land cover. - Direct measurements of CO 2 fluxes reveal the impact of urbanisation and human behavioural patterns on the atmosphere at sub-daily to inter-annual time scales

Living in Heterogeneous Woodlands - Are Habitat Continuity or Quality Drivers of Genetic Variability in a Flightless Ground Beetle?

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Tamar Marcus

Full Text Available Although genetic diversity is one of the key components of biodiversity, its drivers are still not fully understood. While it is known that genetic diversity is affected both by environmental parameters as well as habitat history, these factors are not often tested together. Therefore, we analyzed 14 microsatellite loci in Abax parallelepipedus, a flightless, forest dwelling ground beetle, from 88 plots in two study regions in Germany. We modeled the effects of historical and environmental variables on allelic richness, and found for one of the regions, the Schorfheide-Chorin, a significant effect of the depth of the litter layer, which is a main component of habitat quality, and of the sampling effort, which serves as an inverse proxy for local population size. For the other region, the Schwäbische Alb, none of the potential drivers showed a significant effect on allelic richness. We conclude that the genetic diversity in our study species is being driven by current local population sizes via environmental variables and not by historical processes in the studied regions. This is also supported by lack of genetic differentiation between local populations sampled from ancient and from recent woodlands. We suggest that the potential effects of former fragmentation and recolonization processes have been mitigated by the large and stable local populations of Abax parallelepipedus in combination with the proximity of the ancient and recent woodlands in the studied landscapes.

Determining effects of an all weather logging road on winter woodland caribou habitat use in south-eastern Manitoba

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Doug W. Schindler

2007-04-01

Full Text Available The Owl Lake boreal woodland caribou population is the most southerly population in Manitoba. It is provincially ranked as a High Conservation Concern Population. Forestry operations exist in the area and there are plans for further forest harvest and renewal. The Happy Lake logging road is the only main access through the Owl Lake winter range. This logging road is currently closed to the public and access is limited to forestry operations during specific times of the year. An integrated forestry/caribou management strategy for the area provides for the maintenance of minimum areas of functional habitat. Habitat quality along the road was compared to habitat quality in the winter core use areas, within the winter range and outside the winter range. To evaluate the extent of functional habitat near the road, we conducted animal location and movement analysis using GPS data collected from January 2002 to March 2006. Habitat quality in the winter range, core use areas and along the road were assessed and found to be similar. Analysis of caribou locations and movement illustrate less use of high quality habitat adjacent to the Happy Lake Road. Loss of functional habitat is suggested to occur within 1 kilometre of the road. This potential loss of functional habitat should be incorporated into integrated forestry and caribou conservation strategies. Road management is recommended to minimize the potential sensory disturbance and associated impacts of all weather access on boreal woodland caribou.

Identification, Isolation, and Expression Analysis of Heat Shock Transcription Factors in the Diploid Woodland Strawberry Fragaria vesca

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Yang eHu

2015-09-01

Full Text Available Heat shock transcription factors (Hsfs are known to play dominant roles in plant responses to heat, as well as other abiotic or biotic stress stimuli. While the strawberry is an economically important fruit plant, little is known about the Hsf family in the strawberry. To explore the functions of strawberry Hsfs in abiotic and biotic stress responses, this study identified 17 Hsf genes (FvHsfs in a wild diploid woodland strawberry (Fragaria vesca, 2n = 2x = 14 and isolated 14 of these genes. Phylogenetic analysis divided the strawberry FvHsfs genes into three main groups. The evolutionary and structural analyses revealed that the FvHsf family is conserved. The promoter sequences of the FvHsf genes contain upstream regulatory elements corresponding to different stress stimuli. In addition, 14 FvHsf-GFP fusion proteins showed differential subcellular localization in Arabidopsis mesophyll protoplasts. Furthermore, we examined the expression of the 17 FvHsf genes in wild diploid woodland strawberries under various conditions, including abiotic stresses (heat, cold, drought, and salt, biotic stress (powdery mildew infection, and hormone treatments (abscisic acid, ethephon, methyl jasmonate, and salicylic acid. Fifteen of the 17 FvHsf genes exhibited distinct changes on the transcriptional level during heat treatment. Of these 15 FvHsfs, 8 FvHsfs also exhibited distinct responses to other stimuli on the transcriptional level, indicating versatile roles in the response to abiotic and biotic stresses. Taken together, the present work may provide the basis for further studies to dissect FvHsf function in response to stress stimuli.

Superfund Record of Decision (EPA Region 2): Woodland Township Route 72 site, Burlington County, New Jersey (first remedial action), May 16, 1990

International Nuclear Information System (INIS)

1990-01-01

The 12-acre Woodland Route 72 Dump site is an abandoned hazardous waste dump in Woodland Township, Burlington County, New Jersey. The site is being remediated concurrently with another abandoned dump. Several chemical manufacturing firms dumped chemicals and other wastes into trenches and lagoons or burned the waste at the sites from the early 1950s to 1962. The primary contaminants of concern affecting the surface soil, sediment, sludge, debris, and ground water are VOCs including benzene, toluene, TCE and xylenes; organics including PAHs, pesticides, and phenols; radionuclides (e.g., uranium and thorium series); and metals including lead and chromium. The selected remedial action for the site includes excavation, further characterization, and offsite disposal at a permitted facility of 54,000 cubic yards (total from both sites) of contaminated surface soil, sludges, debris and sediment; offsite disposal of 19 cubic yards (total from both sites) of radiologically contaminated surface materials including a drum of radioactive pellets; ground water pumping and treatment with treatment to be determined during design. The total estimated present worth cost for the concurrent remedial actions at the Route 72 and Route 532 sites is $142,200,000

Analysis of forest stands used by wintering woodland caribou in Ontario

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K. Antoniak

1998-03-01

Full Text Available Two summers' field surveys at 9 locations in northwestern Ontario showed that woodland caribou (Rangifer tarandus caribou wintering areas supported jack pine and black spruce stands with low tree densities (mean 1552 trees/ ha, 39% of a fully stocked stand, low basal areas (mean 14.14 m2/ha, low volumes (mean 116 mVha, 68% of Normal Yield Tables and short heights (95% of stands 12 m or less. Ecologically, most sights were classed V30. Significantly more lichen (averaging 39% lichen ground cover was found on plots used by caribou. Three measured areas showed few shrubs, possibly enhancing escape possibilities and reducing browse attractive to moose. An HIS model predicted known locations of caribou winter habitat from FRI data with 76% accuracy. Landsat imagery theme 3 (open conifer produced 74% accuracy. Combining these methods permitted prediction of all 50 test sites. The low volumes of timber found in caribou wintering areas suggest that setting aside reserves for caribou winter habitat would not sacrifice as much wood product value as might at first appear.

Values and motivations of private forest owners in the United States: a framework based on open-ended responses in the national woodland owner survey

Science.gov (United States)

David N. Bengston; Brett J. Butler; Stanley T. Asah

2009-01-01

The National Woodland Owner Survey (NWOS) is a recurring and comprehensive national survey of private forest landowners in the United States, and is a social complement to the U.S. Forest Service Forest Inventory and Analysis program's biologic resource inventory. An open-ended question in the NWOS explores private forest owners' motivations and values...

Difference in tree growth responses to climate at the upper treeline: Qilian Juniper in the Anyemaqen Mountains.

Science.gov (United States)

Peng, Jianfeng; Gou, Xiaohua; Chen, Fahu; Li, Jinbao; Liu, Puxing; Zhang, Yong; Fang, Keyan

2008-08-01

Three ring-width chronologies were developed from Qilian Juniper (Sabina przewalskii Kom.) at the upper treeline along a west-east gradient in the Anyemaqen Mountains. Most chronological statistics, except for mean sensitivity (MS), decreased from west to east. The first principal component (PC1) loadings indicated that stands in a similar climate condition were most important to the variability of radial growth. PC2 loadings decreased from west to east, suggesting the difference of tree-growth between eastern and western Anyemaqen Mountains. Correlations between standard chronologies and climatic factors revealed different climatic influences on radial growth along a west-east gradient in the study area. Temperature of warm season (July-August) was important to the radial growth at the upper treeline in the whole study area. Precipitation of current May was an important limiting factor of tree growth only in the western (drier) upper treeline, whereas precipitation of current September limited tree growth in the eastern (wetter) upper treeline. Response function analysis results showed that there were regional differences between tree growth and climatic factors in various sampling sites of the whole study area. Temperature and precipitation were the important factors influencing tree growth in western (drier) upper treeline. However, tree growth was greatly limited by temperature at the upper treeline in the middle area, and was more limited by precipitation than temperature in the eastern (wetter) upper treeline.

Decision-support model to explore the feasibility of using translocation to restore a woodland caribou population in Pukaskwa National Park, Canada

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Emily K. Gonzales

2015-12-01

Full Text Available The distribution and abundance of woodland caribou (Rangifer tarandus caribou have declined dramatically in the past century. Without intervention the most southern population of caribou in eastern North America is expected to disappear within 20 years. Although translocations have reintroduced and reinforced some populations, approximately half of caribou translocation efforts fail. Translocations are resource intensive and risky, and multiple interrelated factors must be considered to assess their potential for success. Structured decision-making tools, such as Bayesian belief networks, provide objective methods to assess different wildlife management scenarios by identifying the key components and relationships in an ecosystem. They can also catalyze dialogue with stakeholders and provide a record of the complex thought processes used in reaching a decision. We developed a Bayesian belief network for a proposed translocation of woodland caribou into a national park on the northeastern coast of Lake Superior, Ontario, Canada. We tested scenarios with favourable (e.g., good physical condition of adult caribou and unfavourable (e.g., high predator densities conditions with low, medium, and high numbers of translocated caribou. Under the current conditions at Pukaskwa National Park, augmenting the caribou population is unlikely to recover the species unless wolf densities remain low (<5.5/1000 km2 or if more than 300 animals could be translocated.

Shifts in soil fungal communities in Tuber melanosporum plantations over a 20-year transition from agriculture fields to oak woodlands

Energy Technology Data Exchange (ETDEWEB)

Bing, L.; Fischer, C.R.; Bonet, J.A.; Castaño, C.; Colinas, C.

2016-07-01

Aim of study: To explore the diversity of soil fungi found in black truffle (Tuber melanosporum) plantations following the introduction of the mycorrhizal-colonized host tree, (Quercus ilex), through the development of the brûlé and production of mature sporocarps. Area of study: This research was carried out province of Teruel, Aragon (central eastern Spain). Material and Methods: Soil samples from 6 plantations were collected beneath Q. ilex trees inoculated with T. melanosporum, of 3, 5, 7, 10, 14 and 20 years after out planting in truffle plantations. Soil DNA was extracted, PCR-amplified and sequenced to compare soil fungi present at different ages. Main results: As tree age increased, we observed an increased frequency of T. melanosporum (from 8% to 71% of sequenced colonies) and concomitant decrease in the combined frequency of Fusarium spp. and Phoma spp. (from 64% to 3%). Research highlights: There are important shifts in species richness and in functional groups in the soil fungal communities in maturing black truffle-oak woodland plantations. The observed inverse relationship between the frequency of soil endophytic and/or pathogenic fungi and that of the mycorrhizal mutualist T. melanosporum provides support to continue a deeper analysis of shifts in fungal communities and functional groups where there is a transition from agriculture fields to woodlands. (Author)

Estimating Arrival Numbers for Informal Recreation: A Geographical Approach and Case Study of British Woodlands

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Marije Schaafsma

2010-02-01

Full Text Available This paper describes a novel methodology for generating models of demand for informal outdoor recreation. We analyze visitor data from multiple forest sites across Great Britain. We introduce a wide range of variables typically omitted from most economic demand models of recreation. These include on-site characteristics, and off-site locational drivers of visitation including substitute and complement availability. A Poisson multilevel model is used to model visitor counts, and the methodology is applied to a dataset of more than 10,000 visits to open-access woodland sites. Results confirm it identifies a broader range of demand drivers than previously observed. The use of nationally available explanatory variables enhances the transferability and hence general applicability of the methodology.

Mountain pine beetles and emerging issues in the management of woodland caribou in Westcentral British Columbia

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Deborah Cichowski

2005-05-01

Full Text Available The Tweedsmuir—Entiako caribou (Rangifer tarandus caribou herd summers in mountainous terrain in the North Tweedsmuir Park area and winters mainly in low elevation forests in the Entiako area of Westcentral British Columbia. During winter, caribou select mature lodgepole pine (Pinus contorta forests on poor sites and forage primarily by cratering through snow to obtain terrestrial lichens. These forests are subject to frequent large-scale natural disturbance by fire and forest insects. Fire suppression has been effective in reducing large-scale fires in the Entiako area for the last 40—50 years, resulting in a landscape consisting primarily of older lodgepole pine forests, which are susceptible to mountain pine beetle (Dendroctonus ponderosae attack. In 1994, mountain pine beetles were detected in northern Tweedsmuir Park and adjacent managed forests. To date, mountain pine beetles have attacked several hundred thousand hectares of caribou summer and winter range in the vicinity of Tweedsmuir Park, and Entiako Park and Protected Area. Because an attack of this scale is unprecedented on woodland caribou ranges, there is no information available on the effects of mountain pine beetles on caribou movements, habitat use or terrestrial forage lichen abundance. Implications of the mountain pine beetle epidemic to the Tweedsmuir—Entiako woodland caribou population include effects on terrestrial lichen abundance, effects on caribou movement (reduced snow interception, blowdown, and increased forest harvesting outside protected areas for mountain pine beetle salvage. In 2001 we initiated a study to investigate the effects of mountain pine beetles and forest harvesting on terrestrial caribou forage lichens. Preliminary results suggest that the abundance of Cladina spp. has decreased with a corresponding increase in kinnikinnick (Arctostaphylos uva-ursi and other herbaceous plants. Additional studies are required to determine caribou movement and

Dogwood Borer (Lepidoptera: Sesiidae) Abundance and Seasonal Flight Activity in Apple Orchards, Urban Landscapes, and Woodlands in Five Eastern States

OpenAIRE

Bergh, J. C.; Leskey, T. C.; Walgenbach, J. F.; Klingeman, W. E.; Kain, D. P.; Zhang, A.

2017-01-01

The relative abundance and seasonal flight activity of dogwood borer, Synanthedon scitula Harris (Lepidoptera: Sesiidae), was measured using weekly records from traps baited with its sex pheromone and deployed in apple orchards, urban landscapes, and native woodland sites in New York, West Virginia, Virginia, North Carolina, and Tennessee in 2005 and 2006. The mean total number of moths captured per site in apple orchards was 3,146 ± 644 and 3095 ± 584 SE in 2005 and 2006, respectively, excee...

Modeling the evolution of riparian woodlands facing climate change in three European rivers with contrasting flow regimes.

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Rui P Rivaes

Full Text Available Global circulation models forecasts indicate a future temperature and rainfall pattern modification worldwide. Such phenomena will become particularly evident in Europe where climate modifications could be more severe than the average change at the global level. As such, river flow regimes are expected to change, with resultant impacts on aquatic and riparian ecosystems. Riparian woodlands are among the most endangered ecosystems on earth and provide vital services to interconnected ecosystems and human societies. However, they have not been the object of many studies designed to spatially and temporally quantify how these ecosystems will react to climate change-induced flow regimes. Our goal was to assess the effects of climate-changed flow regimes on the existing riparian vegetation of three different European flow regimes. Cases studies were selected in the light of the most common watershed alimentation modes occurring across European regions, with the objective of appraising expected alterations in the riparian elements of fluvial systems due to climate change. Riparian vegetation modeling was performed using the CASiMiR-vegetation model, which bases its computation on the fluvial disturbance of the riparian patch mosaic. Modeling results show that riparian woodlands may undergo not only at least moderate changes for all flow regimes, but also some dramatic adjustments in specific areas of particular vegetation development stages. There are circumstances in which complete annihilation is feasible. Pluvial flow regimes, like the ones in southern European rivers, are those likely to experience more pronounced changes. Furthermore, regardless of the flow regime, younger and more water-dependent individuals are expected to be the most affected by climate change.

Transpiration Demand in Southern California Oak Woodlands: Making the Leap from Lab and Individual Tree to Watershed Scale

Science.gov (United States)

Weinberger, J. L.; Quinlan, P. T.; Martin, J.; Tartakovsky, D. M.

2013-12-01

Watershed scale estimates of evapotranspiration (ET) have proven difficult to quantify in areas of native vegetation with uncertain or unknown crop coefficients. In this study, we evaluate the water use in Quercus engelmanni and Quercus agrifolia, two species of oak native to Southern California. Thermal dissipation probes (TDPs) were installed at four locations within a 14,500 acre watershed, comprising 770 acres of Q. agrifolia woodland and 2440 acres of Q. engelmanni woodland. Installation duration ranged from 6 weeks to 14 months. The TDPs were calibrated to each species in the laboratory using limbs ranging from 2 to 5 inches in diameter. Dye was run through each limb at the end of the calibration test in order to establish a relationship between active sapwood area and limb diameter. ET measured in the field for each species was 0.15 to 0.3 times that of the reference evapotranspiration (ETo) derived from the Penman-Monteith equation, with the primary variability in the demand related to measured incident solar radiation. The total water demand for each species is estimated using the laboratory determined relationship between the active sapwood area and the diameter of the limb, and a survey of the tree diameter breast height (DBH) of each tree in the watershed. This study provides new insight into the actual water demand of two native tree species in Southern California and has serious implications for conservation plans, which are often developed using watershed models that apply ETo to all vegetation communities, regardless of actual water demand.

A Spectral Evaluation of Models Performances in Mediterranean Oak Woodlands

Science.gov (United States)

Vargas, R.; Baldocchi, D. D.; Abramowitz, G.; Carrara, A.; Correia, A.; Kobayashi, H.; Papale, D.; Pearson, D.; Pereira, J.; Piao, S.; Rambal, S.; Sonnentag, O.

2009-12-01

Ecosystem processes are influenced by climatic trends at multiple temporal scales including diel patterns and other mid-term climatic modes, such as interannual and seasonal variability. Because interactions between biophysical components of ecosystem processes are complex, it is important to test how models perform in frequency (e.g. hours, days, weeks, months, years) and time (i.e. day of the year) domains in addition to traditional tests of annual or monthly sums. Here we present a spectral evaluation using wavelet time series analysis of model performance in seven Mediterranean Oak Woodlands that encompass three deciduous and four evergreen sites. We tested the performance of five models (CABLE, ORCHIDEE, BEPS, Biome-BGC, and JULES) on measured variables of gross primary production (GPP) and evapotranspiration (ET). In general, model performance fails at intermediate periods (e.g. weeks to months) likely because these models do not represent the water pulse dynamics that influence GPP and ET at these Mediterranean systems. To improve the performance of a model it is critical to identify first where and when the model fails. Only by identifying where a model fails we can improve the model performance and use them as prognostic tools and to generate further hypotheses that can be tested by new experiments and measurements.

Effects of Spatial Distribution of Trees on Density Estimation by Nearest Individual Sampling Method: Case Studies in Zagros Wild Pistachio Woodlands and Simulated Stands

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Y. Erfanifard

2014-06-01

Full Text Available Distance methods and their estimators of density may have biased measurements unless the studied stand of trees has a random spatial pattern. This study aimed at assessing the effect of spatial arrangement of wild pistachio trees on the results of density estimation by using the nearest individual sampling method in Zagros woodlands, Iran, and applying a correction factor based on the spatial pattern of trees. A 45 ha clumped stand of wild pistachio trees was selected in Zagros woodlands and two random and dispersed stands with similar density and area were simulated. Distances from the nearest individual and neighbour at 40 sample points in a 100 × 100 m grid were measured in the three stands. The results showed that the nearest individual method with Batcheler estimator could not calculate density correctly in all stands. However, applying the correction factor based on the spatial pattern of the trees, density was measured with no significant difference in terms of the real density of the stands. This study showed that considering the spatial arrangement of trees can improve the results of the nearest individual method with Batcheler estimator in density measurement.

Shifts in soil fungal communities in Tuber melanosporum plantations over a 20-year transition from agriculture fields to oak woodlands

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Liu Bing

2016-04-01

Full Text Available Aim of study: To explore the diversity of soil fungi found in black truffle (Tuber melanosporum plantations following the introduction of the mycorrhizal-colonized host tree, (Quercus ilex, through the development of the brûlé and production of mature sporocarps.Area of study: This research was carried out province of Teruel, Aragon (central eastern Spain.Material and Methods: Soil samples from 6 plantations were collected beneath Q. ilex trees inoculated with T. melanosporum, of 3, 5, 7, 10, 14 and 20 years after out planting in truffle plantations. Soil DNA was extracted, PCR-amplified and sequenced to compare soil fungi present at different ages.Main results: As tree age increased, we observed an increased frequency of T. melanosporum (from 8% to 71% of sequenced colonies and concomitant decrease in the combined frequency of Fusarium spp. and Phoma spp. (from 64% to 3%.Research highlights: There are important shifts in species richness and in functional groups in the soil fungal communities in maturing black truffle-oak woodland plantations. The observed inverse relationship between the frequency of soil endophytic and/or pathogenic fungi and that of the mycorrhizal mutualist T. melanosporum provides support to continue a deeper analysis of shifts in fungal communities and functional groups where there is a transition from agriculture fields to woodlands.Abbreviations used: Ectomycorrhiza (ECM fungus; Vesicular arbuscular mycorrhiza (VAM; Operational taxonomic unit (OTU.

Group dynamics of zebra and wildebeest in a woodland savanna: effects of predation risk and habitat density.

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Maria Thaker

Full Text Available BACKGROUND: Group dynamics of gregarious ungulates in the grasslands of the African savanna have been well studied, but the trade-offs that affect grouping of these ungulates in woodland habitats or dense vegetation are less well understood. We examined the landscape-level distribution of groups of blue wildebeest, Connochaetes taurinus, and Burchell's zebra, Equus burchelli, in a predominantly woodland area (Karongwe Game Reserve, South Africa; KGR to test the hypothesis that group dynamics are a function of minimizing predation risk from their primary predator, lion, Panthera leo. METHODOLOGY/PRINCIPAL FINDINGS: Using generalized linear models, we examined the relative importance of habitat type (differing in vegetation density, probability of encountering lion (based on utilization distribution of all individual lions in the reserve, and season in predicting group size and composition. We found that only in open scrub habitat, group size for both ungulate species increased with the probability of encountering lion. Group composition differed between the two species and was driven by habitat selection as well as predation risk. For both species, composition of groups was, however, dominated by males in open scrub habitats, irrespective of the probability of encountering lion. CONCLUSIONS/SIGNIFICANCE: Distribution patterns of wildebeest and zebra groups at the landscape level directly support the theoretical and empirical evidence from a range of taxa predicting that grouping is favored in open habitats and when predation risk is high. Group composition reflected species-specific social, physiological and foraging constraints, as well as the importance of predation risk. Avoidance of high resource open scrub habitat by females can lead to loss of foraging opportunities, which can be particularly costly in areas such as KGR, where this resource is limited. Thus, landscape-level grouping dynamics are species specific and particular to the

Air humidity as key determinant of morphogenesis and productivity of the rare temperate woodland fern Polystichum braunii.

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Schwerbrock, R; Leuschner, C

2016-07-01

(1) Most ferns are restricted to moist and shady habitats, but it is not known whether soil moisture or atmospheric water status are decisive limiting factors, or if both are equally important. (2) Using the rare temperate woodland fern Polystichum braunii, we conducted a three-factorial climate chamber experiment (soil moisture (SM) × air humidity (RH) × air temperature (T)) to test the hypotheses that: (i) atmospheric water status (RH) exerts a similarly large influence on the fern's biology as soil moisture, and (ii) both a reduction in RH and an increase in air temperature reduce vigour and growth. (3) Nine of 11 morphological, physiological and growth-related traits were significantly influenced by an increase in RH from 65% to 95%, leading to higher leaf conductance, increased above- and belowground productivity, higher fertility, more epidermal trichomes and fewer leaf deformities under high air humidity. In contrast, soil moisture variation (from 66% to 70% in the moist to ca. 42% in the dry treatment) influenced only one trait (specific leaf area), and temperature variation (15 °C versus 19 °C during daytime) only three traits (leaf conductance, root/shoot ratio, specific leaf area); RH was the only factor affecting productivity. (4) This study is the first experimental proof for a soil moisture-independent air humidity effect on the growth of terrestrial woodland ferns. P. braunii appears to be an air humidity hygrophyte that, whithin the range of realistic environmental conditions set in this study, suffers more from a reduction in RH than in soil moisture. A climate warming-related increase in summer temperatures, however, seems not to directly threaten this endangered species. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Modelling above Ground Biomass in Tanzanian Miombo Woodlands Using TanDEM-X WorldDEM and Field Data

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Stefano Puliti

2017-09-01

Full Text Available The use of Interferometric Synthetic Aperture Radar (InSAR data has great potential for monitoring large scale forest above ground biomass (AGB in the tropics due to the increased ability to retrieve 3D information even under cloud cover. To date; results in tropical forests have been inconsistent and further knowledge on the accuracy of models linking AGB and InSAR height data is crucial for the development of large scale forest monitoring programs. This study provides an example of the use of TanDEM-X WorldDEM data to model AGB in Tanzanian woodlands. The primary objective was to assess the accuracy of a model linking AGB with InSAR height from WorldDEM after the subtraction of ground heights. The secondary objective was to assess the possibility of obtaining InSAR height for field plots when the terrain heights were derived from global navigation satellite systems (GNSS; i.e., as an alternative to using airborne laser scanning (ALS. The results revealed that the AGB model using InSAR height had a predictive accuracy of R M S E = 24.1 t·ha−1; or 38.8% of the mean AGB when terrain heights were derived from ALS. The results were similar when using terrain heights from GNSS. The accuracy of the predicted AGB was improved when compared to a previous study using TanDEM-X for a sub-area of the area of interest and was of similar magnitude to what was achieved in the same sub-area using ALS data. Overall; this study sheds new light on the opportunities that arise from the use of InSAR data for large scale AGB modelling in tropical woodlands.

Does Management Matter?: Using MISR to Assess the Effects of Charcoal Production and Management on Woodland Regeneration

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Wurster, K.

2008-12-01

In much of Sub-Saharan Africa, more than 75 percent of a rapidly growing urban population depends on charcoal as their primary source of energy for cooking. The high demand for charcoal has led many to believe that charcoal harvesting catalyzes widespread deforestation. The Senegalese government and international donors have initiated projects within protected areas to combat deforestation and created land management plans to sustainably harvest charcoal. To date, the effects of forest management techniques on forest sustainability are still in question. This research uses a multiphase approach integrating satellite analysis with field surveys to assess the effect of varying forest management strategies on forest regeneration and sustainability after charcoal harvesting. Phase I involved testing the Multiangle Imaging SpectroRadiometer (MISR) satellites capability in detecting structural changes in vegetative cover caused by charcoal harvesting and production. Analysis of the MISR derived k(red) parameter showed MISR can consistently differentiate between forest cover types and successfully differentiates between sites at pre- and post-charcoal harvest stages. Phase II conducted forestry and social surveys comparing and contrasting local effects of land management, land use, and charcoal production on forest regeneration. Phase III uses the local surveys to validate and train the regional remote sensing data to assess the effectiveness of land management in promoting forest regeneration and sustainability after charcoal harvesting. Combining detailed local knowledge with the regional capabilities of MISR provide valuable insight into the factors that control woodland regeneration and sustainability. Preliminary results from phases II and III indicate that both field and remotely sensed variations in forest cover, tree regeneration, and land use change does not vary when compared against land management type. Final results will provide managers with additional

Temporal Dynamics of Arthropods on Six Tree Species in Dry Woodlands on the Caribbean Island of Puerto Rico

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Beltrán, William; Wunderle, Joseph M.

2014-01-01

Abstract The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change. We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis–Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various arthropod taxa were highly variable from year to year. Abundance for most taxa did not show significant seasonality over the 3 yr, although most taxa had abundance peaks each year. However, Homoptera displayed high seasonality with significant temporal aggregations in each year. Formicidae, Orthoptera, and Coleoptera showed high variation in abundance between wet and dry periods, whereas Hemiptera were consistently more abundant in the wet period. Seasonal differences in mean abundance were found only in a few taxa on Tamarindus indica L. , Bucida buceras L. , Pithecellobium dulce , and (Roxburgh) Benth. Mean arthropod abundance varied among tree species, with highest numbers on Prosopis juliflora , (Swartz) De Candolle, Pi. dulce , Leucaena leucocephala , and (Lamarck) de Wit. Abundance of Araneae, Orthoptera, Coleoptera, Lepidoptera larvae, and all arthropods showed weak relationships with one or more climatic variables (rainfall, maximum temperature, or relative humidity). Body size of arthropods was usually largest during the dry periods. Overall, total foliage arthropod abundance showed no consistent seasonality among years, which may become a more common trend in dry forests and woodlands in the Caribbean if seasonality of rainfall becomes less predictable. PMID:25502036

Reactive nitrogen oxides and ozone above a taiga woodland

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Bakwin, Peter S.; Jacob, Daniel J.; Wofsy, Steven C.; Munger, J. William; Daube, Bruce C.; Bradshaw, John D.; Sandholm, Scott T.; Talbot, Robert W.; Singh, Hanwant B.; Gregory, Gerald L.

1994-01-01

Measurements of reactive nitrogen oxides (NO(x) and NO(y)) and ozone (O3) were made in the planetary boundary layer (PBL) above a taiga woodland in northern Quebec, Canada, during June-August, 1990, as part of NASA Artic Boundary Layer Expedition (ABLE) 3B. Levels of nitrogen oxides and O3 were strongly modulated by the synoptic scale meteorology that brought air from various source regions to the site. Industrial pollution from the Great Lakes region of the U.S. and Canada appears to be a major source for periodic elevation of NO(x), and NO(y) and O3. We find that NO/NO2 ratios at this site at midday were approximately 50% those expected from a simple photochemical steady state between NO(x) and O3, in contrast to our earlier results from the ABLE 3A tundra site. The difference between the taiga and tundra sites is likely due to much larger emissions of biogenic hydrocarbons (particularly isoprene) from the taiga vegetation. Hydrocarbon photooxidation leads to relatively rapid production of peroxy radicals, which convert NO to NO2, at the taiga site. Ratios of NO(x) to NO(y) were typically 2-3 times higher in the PBL during ABLE 3B than during ABLE 3A. This is probably the result of high PAN levels and suppressed formation of HNO3 from NO2 due to high levels of biogenic hydrocarbons at the ABLE 3B site.

Agriculture expansion, wood energy and woody encroachment in the Miombo woodlands: striving towards sustainability in Zambia.

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Pelletier, J.

2017-12-01

Agricultural expansion is mostly done at the expense of forests and woodlands in the tropics. In Sub-Saharan Africa, forests are also critical as providers of wood energy for domestic consumption with a clear majority of households depending on firewood and charcoal as primary source of energy. Using Zambia as a case study, we look at the link between agricultural expansion, wood energy and the sustainability of forest resources. Zambia has been identified as having one of the highest rates of deforestation in the world, but there is large uncertainty in these estimates. The government of Zambia has identified charcoal production as one of the main of drivers of forest cover loss and is targeting this practice in their national strategy for reducing emissions from deforestation and forest degradation (REDD+). Other assessment however indicate that agricultural expansion is by far the main driver of deforestation and charcoal production is sustainable in Zambia. These competing evaluations call for a better understanding of the drivers of change. Using two national-scale vegetation surveys and remote sensing data, we compare and validate historical forest cover loss estimates to improve their accuracy. We attribute the change and their associated emissions to specific drivers of deforestation. The ecological properties of areas under change are compared to stable areas over time. Our results from national permanent plots indicate a woody encroachment process in Zambia, a potential ecological response to rising CO2 levels. We found that despite large emissions from deforestation, forests and woodlands have been acting as a carbon sink. This research addresses directly the potential feedbacks and responses to competing demands on forests coming from different sectors, including for agriculture and energy, to set the baseline on which to evaluate forest sustainability now and in the future given potentially new ecological conditions. It provides policy relevant

Quantifying trade-offs between future yield levels, food availability and forest and woodland conservation in Benin.

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Duku, Confidence; Zwart, Sander J; van Bussel, Lenny G J; Hein, Lars

2018-01-01

Meeting the dual objectives of food security and ecosystem protection is a major challenge in sub-Saharan Africa (SSA). To this end agricultural intensification is considered desirable, yet, there remain uncertainties regarding the impact of climate change on opportunities for agricultural intensification and the adequacy of intensification options given the rapid population growth. We quantify trade-offs between levels of yield gap closure, food availability and forest and woodland conservation under different scenarios. Each scenario is made up of a combination of variants of four parameters i.e. (1) climate change based on Representative Concentration Pathways (RCPs); (2) population growth based on Shared Socioeconomic Pathways (SSPs); (3) cropland expansion with varying degrees of deforestation; and (4) different degrees of yield gap closure. We carry out these analyses for three major food crops, i.e. maize, cassava and yam, in Benin. Our analyses show that in most of the scenarios, the required levels of yield gap closures required to maintain the current levels of food availability can be achieved by 2050 by maintaining the average rate of yield increases recorded over the past two and half decades in addition to the current cropping intensity. However, yields will have to increase at a faster rate than has been recorded over the past two and half decades in order to achieve the required levels of yield gap closures by 2100. Our analyses also show that without the stated levels of yield gap closure, the areas under maize, cassava and yam cultivation will have to increase by 95%, 102% and 250% respectively in order to maintain the current levels of per capita food availability. Our study shows that food security outcomes and forest and woodland conservation goals in Benin and likely the larger SSA region are inextricably linked together and require holistic management strategies that considers trade-offs and co-benefits. Copyright © 2017 Elsevier B.V. All

The diverse values and motivations of family forest owners in the United States: An analysis of an open-ended question in the National Woodland Owner Survey

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David N. Bengston; Stanley T. Asah; Brett J. Butler

2011-01-01

The number of family forest owners in the USA has increased continuously in recent decades, and the fate of much of US forests lies in the hands of this diverse and dynamic group of people. The National Woodland Owner Survey (NWOS) is a recurring and comprehensive national survey of US private forest owners, including family forest owners. The NWOS includes an open-...

Volume and Aboveground Biomass Models for Dry Miombo Woodland in Tanzania

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Ezekiel Edward Mwakalukwa

2014-01-01

Full Text Available Tools to accurately estimate tree volume and biomass are scarce for most forest types in East Africa, including Tanzania. Based on a sample of 142 trees and 57 shrubs from a 6,065 ha area of dry miombo woodland in Iringa rural district in Tanzania, regression models were developed for volume and biomass of three important species, Brachystegia spiciformis Benth. (n = 40, Combretum molle G. Don (n = 41, and Dalbergia arbutifolia Baker (n = 37 separately, and for broader samples of trees (28 species, n = 72, shrubs (16 species, n = 32, and trees and shrubs combined (44 species, n = 104. Applied independent variables were log-transformed diameter, height, and wood basic density, and in each case a range of different models were tested. The general tendency among the final models is that the fit improved when height and wood basic density were included. Also the precision and accuracy of the predictions tended to increase from general to species-specific models. Except for a few volume and biomass models developed for shrubs, all models had R2 values of 96–99%. Thus, the models appear robust and should be applicable to forests with similar site conditions, species, and diameter ranges.

Fuels Inventories in the Los Alamos National Laboratory Region: 1997

International Nuclear Information System (INIS)

Balice, R.G.; Oswald, B.P.; Martin, C.

1999-01-01

Fifty-four sites were surveyed for fuel levels, vegetational structures, and topographic characteristics. Most of the surveyed sites were on Los Alamos National Laboratory property, however, some surveys were also conducted on U.S. Forest Service property. The overall vegetation of these sites ranged from pinon-juniper woodlands to ponderosa pine forests to mixed conifer forests, and the topographic positions included canyons, mesas, and mountains. The results of these surveys indicate that the understory fuels are the greatest in mixed conifer forests and that overstory fuels are greatest in both mixed conifer forests and ponderosa pine forests on mesas. The geographic distribution of these fuels would suggest a most credible wildfire scenario for the Los Alamos region. Three major fires have occurred since 1954 and these fires behaved in a manner that is consistent with this scenario. The most credible wildfire scenario was also supported by the results of BEHAVE modeling that used the fuels inventory data as inputs. Output from the BEHAVE model suggested that catastrophic wildfires would continue to occur during any season with sufficiently dry, windy weather

An integrative analysis of the dynamics of landscape- and local-scale colonization of Mediterranean woodlands by Pinus halepensis.

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Efrat Sheffer

Full Text Available Afforestation efforts have resulted in extensive plantations of either native or non-native conifers, which in many regions has led to the spread of those conifers into surrounding natural vegetation. This process of species colonization can trigger profound changes in both community dynamics and ecosystem processes. Our study disentangled the complexity of a process of colonization in a heterogeneous landscape into a simple set of rules. We analyzed the factors that control the colonization of natural woodland ecosystems by Pinus halepensis dispersing from plantations in the Mediterranean region of Israel. We developed maximum-likelihood models to explain the densities of P. halepensis colonizing natural woodlands. Our models unravel how P. halepensis colonization is controlled by factors that determine colonization pressure by dispersing seeds and by factors that control resistance to colonization of the natural ecosystems. Our models show that the combination of different seed arrival processes from local, landscape, and regional scales determine pine establishment potential, but the relative importance of each component varied according to seed source distribution. Habitat resistance, determined by abiotic and biotic conditions, was as important as propagule input in determining the density of pine colonization. Thus, despite the fact that pine propagules disperse throughout the landscape, habitat heterogeneity within the natural ecosystems generates significant variation in the actual densities of colonized pine. Our approach provides quantitative measures of how processes at different spatial scales affect the distribution and densities of colonizing species, and a basis for projection of expected distributions. Variation in colonization rates, due to landscape-scale heterogeneity in both colonization pressure and resistance to colonization, can be expected to produce a diversity of new ecosystems. This work provides a template for

Temporal dynamics of arthropods on six tree species in dry woodlands on the Caribbean Island of Puerto Rico.

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Beltrán, William; Wunderle, Joseph M

2014-01-01

The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change. We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis-Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various arthropod taxa were highly variable from year to year. Abundance for most taxa did not show significant seasonality over the 3 yr, although most taxa had abundance peaks each year. However, Homoptera displayed high seasonality with significant temporal aggregations in each year. Formicidae, Orthoptera, and Coleoptera showed high variation in abundance between wet and dry periods, whereas Hemiptera were consistently more abundant in the wet period. Seasonal differences in mean abundance were found only in a few taxa on Tamarindus indica L., Bucida buceras L., Pithecellobium dulce, and (Roxburgh) Benth. Mean arthropod abundance varied among tree species, with highest numbers on Prosopis juliflora, (Swartz) De Candolle, Pi. dulce, Leucaena leucocephala, and (Lamarck) de Wit. Abundance of Araneae, Orthoptera, Coleoptera, Lepidoptera larvae, and all arthropods showed weak relationships with one or more climatic variables (rainfall, maximum temperature, or relative humidity). Body size of arthropods was usually largest during the dry periods. Overall, total foliage arthropod abundance showed no consistent seasonality among years, which may become a more common trend in dry forests and woodlands in the Caribbean if seasonality of rainfall becomes less predictable. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

A minimal model of fire-vegetation feedbacks and disturbance stochasticity generates alternative stable states in grassland–shrubland–woodland systems

International Nuclear Information System (INIS)

Batllori, Enric; Ackerly, David D; Moritz, Max A

2015-01-01

Altered disturbance regimes in the context of global change are likely to have profound consequences for ecosystems. Interactions between fire and vegetation are of particular interest, as fire is a major driver of vegetation change, and vegetation properties (e.g., amount, flammability) alter fire regimes. Mediterranean-type ecosystems (MTEs) constitute a paradigmatic example of temperate fire-prone vegetation. Although these ecosystems may be heavily impacted by global change, disturbance regime shifts and the implications of fire-vegetation feedbacks in the dynamics of such biomes are still poorly characterized. We developed a minimal modeling framework incorporating key aspects of fire ecology and successional processes to evaluate the relative influence of extrinsic and intrinsic factors on disturbance and vegetation dynamics in systems composed of grassland, shrubland, and woodland mosaics, which characterize many MTEs. In this theoretical investigation, we performed extensive simulations representing different background rates of vegetation succession and disturbance regime (fire frequency and severity) processes that reflect a broad range of MTE environmental conditions. Varying fire-vegetation feedbacks can lead to different critical points in underlying processes of disturbance and sudden shifts in the vegetation state of grassland–shrubland–woodland systems, despite gradual changes in ecosystem drivers as defined by the environment. Vegetation flammability and disturbance stochasticity effectively modify system behavior, determining its heterogeneity and the existence of alternative stable states in MTEs. Small variations in system flammability and fire recurrence induced by climate or vegetation changes may trigger sudden shifts in the state of such ecosystems. The existence of threshold dynamics, alternative stable states, and contrasting system responses to environmental change has broad implications for MTE management. (letter)

Life-cycle assessment of typical Portuguese cork oak woodlands.

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González-García, Sara; Dias, Ana Cláudia; Arroja, Luis

2013-05-01

Cork forest systems are responsible for making an important economic contribution to the Mediterranean region, especially Portugal where the cork oak woodlands or montados contain about 32% of the world's area. The environmental profile derived from reproduction cork production and extraction in two Portuguese regions (Tagus valley and Alentejo) representative of the Portuguese sector were assessed in detail using the Life-Cycle Assessment (LCA) methodology from a cradle-to-gate perspective. The production line was divided into four stages considering all the processes involved: stand establishment, stand management, cork stripping and field recovery. According to the environmental results, there were remarkable differences between the two production scenarios mainly due to the intensity and repetition of forest activities even though the cork yield was reported to be the same. The management system in the Alentejo region presented the worse environmental profile in almost all the impact categories under assessment, mainly due to the shorter cycle duration of the mechanical cleaning and pruning processes. Cork stripping was identified in both scenarios as the production stage with the highest contribution to the environmental profile due to the cleaning and pruning processes. A sensitivity assessment concerning the cork yield was performed since the average production yields in the Portuguese montados are lower than the ones used in this study. Thus, if the cork yield is reduced, the environmental profile in both scenarios gets worse since almost all the forest activities involved are the same. Copyright © 2013 Elsevier B.V. All rights reserved.

Above- and Belowground Biomass Models for Trees in the Miombo Woodlands of Malawi

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Daud J. Kachamba

2016-02-01

Full Text Available In this study we present general (multiple tree species from several sites above- and belowground biomass models for trees in the miombo woodlands of Malawi. Such models are currently lacking in the country. The modelling was based on 74 trees comprising 33 different species with diameters at breast height (dbh and total tree height (ht ranging from 5.3 to 2 cm and from 3.0 to 25.0 m, respectively. Trees were collected from four silvicultural zones covering a wide range of conditions. We tested different models including dbh, ht and wood specific gravity ( ρ as independent variables. We evaluated model performance using pseudo-R2, root mean square error (RMSE, a covariance matrix for the parameter estimates, mean prediction error (MPE and relative mean prediction error (MPE%. Computation of MPE% was based on leave-one-out cross-validation. Values of pseudo-R2 and MPE% ranged 0.82–0.97 and 0.9%–2.8%, respectively. Model performance indicated that the models can be used over a wide range of geographical and ecological conditions in Malawi.

Woodland caribou persistence and extirpation in relic populations on Lake Superior

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Arthur T. Bergerud

2007-04-01

Full Text Available Extended: The hypothesis was proposed that woodland caribou (Rangifer tarandus caribou in North America had declined due to wolf predation and over-hunting rather than from a shortage of winter lichens (Bergerud, 1974. In 1974, two study areas were selected for testing: for the lichen hypothesis, we selected the Slate Islands in Lake Superior (36 km2, a closed canopy forest without terrestrial lichens, wolves, bears, or moose; for the predation hypothesis, we selected the nearby Pukaskwa National Park (PNP where terrestrial lichens, wolves, bears, and moose were present. Both areas were monitored from 1974 to 2003 (30 years. The living and dead caribou on the Slates were estimated by the ‘King census’ strip transect (mean length 108±9.3 km, extremes 22-190, total 3026 km and the Lincoln Index (mean tagged 45±3.6, extremes 15-78. The mean annual population on the Slate Islands based on the strip transects was 262±22 animals (extremes 104-606, or 7.3/km2 (29 years and from the Lincoln Index 303±64 (extremes 181-482, or 8.4/km2 (23 years. These are the highest densities in North America and have persisted at least since 1949 (56 years. Mountain maple (Acer spicatum interacted with caribou density creating a record in its age structure which corroborates persistence at relatively high density from c. 1930. The mean percentage of calves was 14.8±0.34% (20 years in the fall and 14.1±1.95% (19 years in late winter. The Slate Islands herd was regulated by the density dependent abundance of summer green foods and fall physical condition rather than density independent arboreal lichen availability and snow depths. Two wolves (1 wolf/150 caribou crossed to the islands in 1993-94 and reduced two calf cohorts (3 and 4.9 per cent calves while female adult survival declined from a mean of 82% to 71% and the population declined ≈100 animals. In PNP, caribou/moose/wolf populations were estimated by aerial surveys (in some years assisted by telemetry

Effects of excluding goat herbivory on Acacia tortilis woodland around pastoralist settlements in northwest Kenya

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Oba, Gufu

1998-08-01

Browsing by goats is considered to cause poor tree regeneration and reduced tree growth around settlements throughout the arid zones of sub-Saharan Africa. This study investigated whether excluding goats from Acacia tortilis woodlands increased tree regeneration, current season's shoot growth rates and browse production over a period of 52 months between 1986 and 1990. The study also investigated the effects of climatic variability on tree growth and browse production. Excluding goat herbivory provided no advantage over continuous browsing for juvenile A. tortilis. Trees on the unbrowsed and on browsed transects increased by 22.2 (standard error [SE] ± 0.53) cm·yr -1 and 25.0 (SE ± 0.58) cm·yr -1, respectively. Fewer but longer shoots were produced by trees on the unbrowsed transects, while trees on the browsed transects invested more in shorter shoots. Net total browse production was lower on unbrowsed (1.73 [standard deviation (SD) ± 4.3] t·ha -1·yr -1) than on the browsed (3.03 [SD ± 3.6] t·ha -1 ·yr -1) transects. Biomass production on unbrowsed and browsed transects was closely correlated with rainfall and presumably soil moisture during wet seasons. Relative growth rates (RGR) of current season's shoots in the two treatments did not differ, implying goat herbivory at moderate stocking density (i.e. 13.0 tropical livestock units [TLU]·km -2) stimulated shoot growth. RGR remained positive except on the browsed transects during 1990, a dry year. Goat browsing pressure was moderate. Total biomass loss on unbrowsed transects was 15.5 %·yr -1 compared with 27.7 %·yr -1 on the browsed transects. These findings do not support the notion that goats always destroy young trees around settlements. Goat herbivory at moderate intensity stimulated shoot productivity. However, the results should not be used to generalize all conditions throughout sub-Saharan Africa, let alone the arid zones of northern Kenya. Rather, there is a need to emphasize individual case

Progress towards the experimental reintroduction of woodland caribou to Minnesota and adjacent Ontario

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Peter A. Jordan

1998-03-01

Full Text Available Woodland caribou (Rangifer tarandus caribou are native to Minnesota but started to decline in the mid 1800s and disappeared from the state by 1940. Their demise had been attributed to extensive timber harvest and ovethunting; but more recently mortality from the meningeal worm, Parelaphostrongylus tenuis, carried by white-tailed deer (Odocoileus virginianus, and increased prédation by timber wolves (Canis lupus and black bears (Ursus americanus have been suggested as additional causes. We describe a current initiative to explore feasibility of restoring caribou to the boundary waters region of Minnesota and Ontario. Feasibility studies have been conducted under the guidance of the North Central Catibou Corporation (NCCC, a non-governmental organization with representation from relevant state, federal, Native American, and Canadian agencies. Results indicate a Within Minnesota the most suitable site for woodland caribou lies within the eastern sector of the Boundary Waters Canoe Area Wilderness (BWCAW, and this is contiguous with a similarly suitable sector of Ontario's Quetico Provincial Park: Together these comprise the recommended 1300-km2 Boundary Waters Caribou Region (BWCR; b Vegetation in the BWCR has changed little since the 1920s when caribou were last present other than effects of fire suppression; c Level of white-tailed deer, hence the meningeal worm, is so low in the BWCR that this factor is unlikely to impede survival of re-introduced caribou; d While wolf numbers within the wider region are relatively high, their impacts may be minimized if caribou are released in small, widely scattered groups; in addition, an abundance of lakes with islands affords good summer-time prédation security; e Threat to calves from black bears, probably more numerous than in earlier times, appears lessened by the security of lakeshores and islands; and f A simulation model, combining knowledge from elsewhere with the BWCR assessment, suggests that

Habitat suitability—density relationship in an endangered woodland species: the case of the Blue Chaffinch (Fringilla polatzeki

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Luis M. Carrascal

2017-09-01

Full Text Available Background Understanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs. Methods We studied the Gran Canaria blue chaffinch (Fringilla polatzeki, a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994. Results The variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July–September. The observed local abundance of the blue chaffinch in Inagua (survey data was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions. The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195–430 blue chaffinches in Inagua since 2011 (95% CI, the smallest population size of a woodland passerine in the Western Palearctic. Discussion Habitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the

Available nitrogen: A time-based study of manipulated resource islands

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Stubbs, Michelle M.; Pyke, David A.

2005-01-01

Spatial and temporal heterogeneity of available nitrogen are critical determinants of the distribution and abundance of plants and animals in ecosystems. Evidence for the resource island theory suggests that soils below tree and shrub canopies contain higher amounts of resources, including available nitrogen, than are present in interspace areas. Disturbances, such as prescribed fire and tree removal, are common management practices in shrub-woodland ecosystems, but it is not known if these practices affect resource islands. We examined temporal variation in resource islands of available nitrogen and their retention after fire and woody plant removal. From August 1997 to October 1998, soil nitrate (NO3−) and ammonium (NH4+) were measured monthly from canopy and interspace plots within four juniper-sagebrush sites along a precipitation gradient in central Oregon, USA. At each site, soil samples were collected from untreated plots, plots in which woody plants were removed, and those treated with prescribed fire in fall 1997. In burned treatments, canopy concentrations were significantly higher than interspace concentrations throughout the measurement period. Canopy NO3− and NH4+ concentrations were significantly higher on burned vs. unburned treatments for four months after fire. After woody plant removal, NO3− and NH4+ concentrations did not differ from the controls. Untreated control areas had higher NO3− and NH4+ concentrations under juniper canopies for nearly all months. Wetter sites had smaller differences between canopy and interspace concentrations through time than did the two drier sites. In relation to NO3− and NH4+ in this ecosystem, resource islands appear to be more ephemeral in wetter sites, and more pronounced following fire disturbances than in controls or those treated by woody plant removal.

Environmental Monitoring Supported by Aerial Photography – a Case Study of the Burnt Down Bugac Juniper Forest, Hungary

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Szatmári József

2016-06-01

Full Text Available Wildfire poses a serious risk in several regions of the world threatening urban, agricultural areas and natural ecosystems as well. Nature conservation has important role to be prepared for the management of postfire environmental degradation and restoration for protected areas preserving valuable ecosystems. The improving temporal and spatial resolution of remote sensing and GIS methods significantly contributes to map the changes for accelerating management steps of restoration. In this study a severe wildfire and its impacts were assessed in case of a protected area of the Kiskunság National Park in Hungary, which was partly burnt down in 2012. The aim of this research was to efficiently and accurately assess the damages and to plan and execute the restoration works using remote sensing tools. Aerial data collection was performed one month, and one year after the fire. In 2014 the regenerated vegetation was surveyed and mapped in the field. Using the aerial photographs and the field data, the degree and extent of the fire damages, the types and the state of the vegetation and the presence and proportion of the invasive species were determined. Semi-automatic methods were used for the classification of completely, partially damaged and undamaged areas. Based on the results, the reforestation of the burnt area is suggested to prevent the overspreading of white poplar against common junipers and to clean the area from the most frequent invasive species. To monitor the regeneration of the vegetation and the spreading of the invasive species, further aerial photography and field campaigns are planned.

The potential of, and threat to, the transfer of ecological knowledge in urban areas: the case of community-based woodland management in Tokyo, Japan

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Kazuaki Tsuchiya

2014-06-01

Full Text Available Urban dwellers often have little knowledge of local ecosystems, but community groups that actively manage local ecosystems can acquire a rich ecological knowledge. Understanding the knowledge transfer process within community groups contributes to the continuous improvement of urban ecosystem management. In this paper, we address three main questions: (1 How is ecological knowledge acquisition linked to boundary and intra-group interactions? (2 Does holding knowledge mean the involvement in actual management activities? (3 Does the aging of community group members threaten the continuity of activities? We selected satoyama woodlands (seminatural woodlands in peri-urban Tokyo, Japan as a study site. We used a mixed method approach that combined a qualitative interview with a quantitative questionnaire. We found that boundary interactions were particularly important at the start of an urban ecological management process, to obtain basic knowledge relating to management activities. Intra-group interaction contributed to knowledge transfer after the starting period. We found that participants possessing considerable ecological knowledge do not necessarily participate in management activities. Findings also indicated that the aging of group members in groups established for more than 10 years was an area of concern for the continuity of group activities. New members did not necessarily solve this aging issue. We conclude that further measures and actions are needed to ensure long-term knowledge transfer among the participants of community groups in urban ecosystem management.

Past and future landscape dynamics in pasture-woodlands of the Swiss Jura Mountains under climate change

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Alexander Peringer

2013-09-01

We present a refined version of the spatially explicit, dynamic simulation model WoodPaM with improved climate sensitivity of simulated vegetation. We investigate pasture-woodland dynamics by applying an innovative combination of retrospective simulations starting in the Middle Ages with prospective simulations following two climate change scenarios. The retrospective simulations demonstrate the strong dependency of the landscape mosaic on both climate and management. In high elevation mountain pastures, climate cooling during the Little Ice Age hindered simulated tree regeneration and reduced forage production of grasslands. Both led to an increase in open grassland and to a structural simplification of the landscape. In turn, climate warming afterwards showed the opposite effect. At lower elevations, high cattle stocking rates generally dominate simulated succession, leading to a slow development of quite homogenous landscapes whose structures are hardly affected by historical climate variability. Aerial photographs suggest that logging and windstorms critically shaped the current landscape, both homogenizing mosaic structures that emerge from selective grazing. Simulations of climate change scenarios suggest delayed but inevitable structural changes in the landscape mosaic and a temporary breakdown of the ecosystem service wood production. The population of currently dominating Norway spruce collapses due to simulated drought. Spruce is only slowly replaced either by beech under moderate warming or by Scots pine under extreme warming. In general, the shift in tree species dominance results in landscapes of less structural richness than today. In order to maintain the mosaic structure of pasture-woodlands, we recommend a future increase in cattle stocking on mountain pastures. The (re- introduction of mixed herds (cattle with horses, sheep, and goats could mitigate the simulated trend towards structural homogenization of the forest-grassland mosaic because

Sit-and-wait pollination in the spring flowering woodland plant, Trillium grandiflorum

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Barrett, Spencer C.H.

2011-07-01

Full Text Available In animal-pollinated plants, reproductive success is commonly limited by pollen availability, which can occur in environments where pollinator activity is scarce or variable. Extended floral longevity to maximize a plant’s access to pollinators may be an adaptation to such uncertain pollination environments. Here, we investigated the effects of flower exposure time to pollinators on female fertility (fruit and seed set in the bee-pollinated woodland herb Trillium grandiflorum, a species with long-lived flowers (~17-21 d that blooms in early spring when pollinator activity is often variable. We experimentally exposed flowers to pollinators for different amounts of time to determine the extent to which floral longevity influenced reproductive success. The amount of time that flowers were exposed to pollinators significantly increased fruit set and seed set per flower, but not seed set per fruit. Our results provide experimental evidence that long floral life spans may function as a ‘sit-and-wait’ pollination strategy to increase the amount of exposure time to pollinators and promote seed set in the unpredictable pollination environments often experienced by early spring ephemerals. In large populations with infrequent pollinator visitation, as commonly occurs in T. grandiflorum, pollination may be a largely stochastic process.

Determining the resilience of carbon dynamics in semi-arid biomes of the Southwestern US to severe drought and altered rainfall patterns

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Litvak, M. E.; Krofcheck, D. J.; Hilton, T. W.; Fox, A. M.; Osuna, J. L.

2011-12-01

Water is critically important for biotic processes in semi-arid ecosystems and 2011 is developing as one of the most severe drought years on record for many parts of the Southwestern US. To quantify the impact of this severe drought on regional carbon and energy balance, we need a more detailed understanding of how water limitation alters ecosystem processes across a range of semi-arid biomes. We quantified the impact of severe drought and changes in both the quantity and distribution of precipitation on ecosystem biotic structure and function across the range of biomes represented in the NM elevation gradient network (desert grassland, creosote shrubland, juniper savanna, piñon-juniper woodland, ponderosa pine forest and subalpine mixed conifer forest). We compared how daily, seasonal and annual carbon and energy balance and their components in each of these biomes respond to changes in rainfall patterns using continuous measurements of carbon, water and energy exchange and associated measurements in each of these biomes during a 5 year period (2006-2011) that included a severe drought, and large variability in both winter precipitation and the timing and intensity of the monsoon. To understand the underlying mechanisms, we used time series of radiation absorbed by vegetation, surface albedo, soil moisture storage, phenology, gross primary productivity (GPP), ecosystem respiration (Re), and WorldView-2 images acquired pre- and post-monsoon in each of these biomes. In all of the biomes except the desert grassland site, the strength and timing of both winter and monsoon precipitation are important controls over carbon and energy dynamics in this region, though we see site-specific sensitivities across the elevation gradient. Over the past 5 years, carbon dynamics in the desert grassland site appears to be decoupled from winter precipitation. In addition, carbon dynamics in disturbed grassland and pinon-juniper ecosystems were more sensitive to severe drought than

Tapeworms (Cestoda: Proteocephalidea) of firewood catfish Sorubimichthys planiceps (Siluriformes: Pimelodidae) from the Amazon River.

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de Chambrier, Alain; Scholz, Tomás

2008-03-01

A survey of proteocephalidean cestodes found in the firewood catfish Sorubimichthys planiceps (Spix et Agassiz) from the Amazon River is provided. The following taxa parasitic in S. planiceps are redescribed on the basis of their type specimens and material collected recently in the Amazon River, near the type localities in Brazil, and in Iquitos, Peru: Monticellia lenha Woodland, 1933; Nomimoscolex lenha (Woodland, 1933) (syn. Proteocephalus lenha Woodland, 1933); and Monticellia megacephala Woodland, 1934, for which a new genus, Lenhataenia, is proposed, with L. megacephala (Woodland, 1934) comb. n. as its type and only species. The new genus is a member of the Monticelliinae, i.e. has all genital organs in the cortex, and is most similar to Chambriella in possessing biloculate suckers and lacking a metascolex. It differs in the morphology of the cirrus-sac that contains a strongly coiled, thick-walled internal sperm duct (vas deferens) and a muscular cirrus of the appearance typical of most proteocephalideans, whereas that of Chambriella is sigmoid, with voluminous, tightly sinuous thick-walled internal sperm duct. In addition, Lenhataenia possesses a well developed internal musculature, whereas the internal musculature of Chambriella is weakly developed, formed by a low number of muscle fibres. The scolex morphology and distribution of microtriches of Peltidocotyle lenha (Woodland, 1933) (syn. Othinoscolex lenha Woodland, 1933 and Othinoscolex myzofer Woodland, 1933), Chambriella sp. and Choanoscolex sp. are described using scanning electron microscopy. The two latter taxa may be new for science and are reported from S. planiceps for the first time.

Benefits to rare plants and highway safety from annual population reductions of a "native invader," white-tailed deer, in a Chicago-area woodland.

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Engeman, Richard M; Guerrant, Travis; Dunn, Glen; Beckerman, Scott F; Anchor, Chris

2014-01-01

Overabundant white-tailed deer are one of the most serious threats to woodland plant communities in the Chicago area. Moreover, the abundant deer in a highly populated area causes economic harm and poses hazards to human safety through collisions with vehicles. The artificial conditions causing the overabundance and resulting consequences qualify the white-tailed deer in the Chicago area to be considered as "native invaders". We examined the benefits of culling deer at a Chicago-area woodland preserve by comparing browse rates on four endangered plant species from years before culling began with years with culling. We also examined deer-vehicle collision and traffic flow rates on area roads from years before culling began and years with culling to assess whether population reductions may have benefited road safety in the area. All four endangered plant species (three orchid species and sweet fern) had lower browse rates in years with culls, although the decreased browsing rates were statistically distinguishable for only two of the species (grass pink orchid and sweet fern). After first verifying that traffic flow rates did not decrease from pre-cull years to years with culls, we analyzed the Illinois Department of Transportation data from area roads based on deer-vehicle collisions causing >US$500 in damage and showed a one-third reduction in deer-vehicle collisions. An economic analysis showed a cost savings during the cull years of US$0.6 million for reducing browsing to just these four monitored plant species and the reduction in deer-vehicle collisions.

The impact of global warming on germination and seedling emergence in Alliaria petiolata, a woodland species with dormancy loss dependent on low temperature.

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Footitt, S; Huang, Z; Ölcer-Footitt, H; Clay, H; Finch-Savage, W E

2018-03-23

The impact of global warming on seed dormancy loss and germination was investigated in Alliaria petiolata (garlic mustard), a common woodland/hedgerow plant in Eurasia, considered invasive in North America. Increased temperature may have serious implications, since seeds of this species germinate and emerge at low temperatures early in spring to establish and grow before canopy development of competing species. Dormancy was evaluated in seeds buried in field soils. Seedling emergence was also investigated in the field, and in a thermogradient tunnel under global warming scenarios representing predicted UK air temperatures through to 2080. Dormancy was simple, and its relief required the accumulation of low temperature chilling time. Under a global warming scenario, dormancy relief and seedling emergence declined and seed mortality increased as soil temperature increased along a thermal gradient. Seedling emergence advanced with soil temperature, peaking 8 days earlier under 2080 conditions. The results indicate that as mean temperature increases due to global warming, the chilling requirement for dormancy relief may not be fully satisfied, but seedling emergence will continue from low dormancy seeds in the population. Adaptation resulting from selection of this low dormancy proportion is likely to reduce the overall population chilling requirement. Seedling emergence is also likely to keep pace with the advancement of biological spring, enabling A. petiolata to maintain its strategy of establishment before the woodland canopy closes. However, this potential for adaptation may be countered by increased seed mortality in the seed bank as soils warm. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Multilocus phylogeography of a widespread savanna-woodland-adapted rodent reveals the influence of Pleistocene geomorphology and climate change in Africa's Zambezi region.

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McDonough, Molly M; Šumbera, Radim; Mazoch, Vladimír; Ferguson, Adam W; Phillips, Caleb D; Bryja, Josef

2015-10-01

Understanding historical influences of climate and physiographic barriers in shaping patterns of biodiversity remains limited for many regions of the world. For mammals of continental Africa, phylogeographic studies, particularly for West African lineages, implicate both geographic barriers and climate oscillations in shaping small mammal diversity. In contrast, studies for southern African species have revealed conflicting phylogenetic patterns for how mammalian lineages respond to both climate change and geologic events such as river formation, especially during the Pleistocene. However, these studies were often biased by limited geographic sampling or exclusively focused on large-bodied taxa. We exploited the broad southern African distribution of a savanna-woodland-adapted African rodent, Gerbilliscus leucogaster (bushveld gerbil) and generated mitochondrial, autosomal and sex chromosome data to quantify regional signatures of climatic and vicariant biogeographic phenomena. Results indicate the most recent common ancestor for all G. leucogaster lineages occurred during the early Pleistocene. We documented six divergent mitochondrial lineages that diverged ~0.270-0.100 mya, each of which was geographically isolated during periods characterized by alterations to the course of the Zambezi River and its tributaries as well as regional 'megadroughts'. Results demonstrate the presence of a widespread lineage exhibiting demographic expansion ~0.065-0.035 mya, a time that coincides with savanna-woodland expansion across southern Africa. A multilocus autosomal perspective revealed the influence of the Kafue River as a current barrier to gene flow and regions of secondary contact among divergent mitochondrial lineages. Our results demonstrate the importance of both climatic fluctuations and physiographic vicariance in shaping the distribution of southern African biodiversity. © 2015 John Wiley & Sons Ltd.

Convergence of tree water use within an arid-zone woodland.

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O'Grady, A P; Cook, P G; Eamus, D; Duguid, A; Wischusen, J D H; Fass, T; Worldege, D

2009-07-01

We examined spatial and temporal patterns of tree water use and aspects of hydraulic architecture in four common tree species of central Australia--Corymbia opaca, Eucalyptus victrix, E. camaldulensis and Acacia aneura--to better understand processes that constrain water use in these environments. These four widely distributed species occupy contrasting niches within arid environments including woodlands, floodplains and riparian environments. Measurements of tree water use and leaf water potential were made at two sites with contrasting water table depths during a period of high soil water availability following summer rainfall and during a period of low soil water availability following 7 months of very little rainfall during 2007. There were significant differences in specific leaf area (SLA), sapwood area to leaf area ratios and sapwood density between species. Sapwood to leaf area ratio increased in all species from April to November indicating a decline in leaf area per unit sapwood area. Despite very little rainfall in the intervening period three species, C. opaca, E. victrix and E. camaldulensis maintained high leaf water potentials and tree water use during both periods. In contrast, leaf water potential and water use in the A. aneura were significantly reduced in November compared to April. Despite contrasting morphology and water use strategies, we observed considerable convergence in water use among the four species. Wood density in particular was strongly related to SLA, sapwood area to leaf area ratios and soil to leaf conductance, with all four species converging on a common relationship. Identifying convergence in hydraulic traits can potentially provide powerful tools for scaling physiological processes in natural ecosystems.

Reduction of tree cover in West African woodlands and promotion in semi-arid farmlands

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Brandt, Martin; Rasmussen, Kjeld; Hiernaux, Pierre; Herrmann, Stefanie; Tucker, Compton J.; Tong, Xiaoye; Tian, Feng; Mertz, Ole; Kergoat, Laurent; Mbow, Cheikh; David, John L.; Melocik, Katherine A.; Dendoncker, Morgane; Vincke, Caroline; Fensholt, Rasmus

2018-05-01

Woody vegetation in farmland acts as a carbon sink and provides ecosystem services for local people, but no macroscale assessments of the impact of management and climate on woody cover exist for drylands. Here we make use of very high spatial resolution satellite imagery to derive wall-to-wall woody cover patterns in tropical West African drylands. Our study reveals that mean woody cover in farmlands along all semi-arid and sub-humid rainfall zones is 16%, on average only 6% lower than in savannahs. In semi-arid Sahel, farmland management promotes woody cover around villages (11%), while neighbouring savannahs had on average less woody cover. However, farmlands in sub-humid zones have a greatly reduced woody cover (21%) as compared with savannahs (33%). In the region as a whole, rainfall, terrain and soil are the most important (80%) determinants of woody cover, while management factors play a smaller (20%) role. We conclude that agricultural expansion causes a considerable reduction of trees in woodlands, but observations in Sahel indicate that villagers safeguard trees on nearby farmlands which contradicts simplistic ideas of a high negative correlation between population density and woody cover.

Environmental and microbial factors influencing methane and nitrous oxide fluxes in Mediterranean cork oak woodlands: trees make a difference.

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Shvaleva, Alla; Siljanen, Henri M P; Correia, Alexandra; Costa E Silva, Filipe; Lamprecht, Richard E; Lobo-do-Vale, Raquel; Bicho, Catarina; Fangueiro, David; Anderson, Margaret; Pereira, João S; Chaves, Maria M; Cruz, Cristina; Martikainen, Pertti J

2015-01-01

Cork oak woodlands (montado) are agroforestry systems distributed all over the Mediterranean basin with a very important social, economic and ecological value. A generalized cork oak decline has been occurring in the last decades jeopardizing its future sustainability. It is unknown how loss of tree cover affects microbial processes that are consuming greenhouse gases in the montado ecosystem. The study was conducted under two different conditions in the natural understory of a cork oak woodland in center Portugal: under tree canopy (UC) and open areas without trees (OA). Fluxes of methane and nitrous oxide were measured with a static chamber technique. In order to quantify methanotrophs and bacteria capable of nitrous oxide consumption, we used quantitative real-time PCR targeting the pmoA and nosZ genes encoding the subunit of particulate methane mono-oxygenase and catalytic subunit of the nitrous oxide reductase, respectively. A significant seasonal effect was found on CH4 and N2O fluxes and pmoA and nosZ gene abundance. Tree cover had no effect on methane fluxes; conversely, whereas the UC plots were net emitters of nitrous oxide, the loss of tree cover resulted in a shift in the emission pattern such that the OA plots were a net sink for nitrous oxide. In a seasonal time scale, the UC had higher gene abundance of Type I methanotrophs. Methane flux correlated negatively with abundance of Type I methanotrophs in the UC plots. Nitrous oxide flux correlated negatively with nosZ gene abundance at the OA plots in contrast to that at the UC plots. In the UC soil, soil organic matter had a positive effect on soil extracellular enzyme activities, which correlated positively with the N2O flux. Our results demonstrated that tree cover affects soil properties, key enzyme activities and abundance of microorganisms and, consequently net CH4 and N2O exchange.

Seasonal habitat use and movements of woodland caribou in the Omineca Mountains, north central British Columbia, 1991-1993

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Mari D. Wood

1996-01-01

Full Text Available From 1991 to 1993, 30 woodland caribou were captured and fitted with radio-collars west of the Williston Reservoir in north central B.C. Monthly radio-telemetry location flights revealed that caribou in the Northern Area, characterized by a complex of mountain ranges, moved greater distances to calving areas than did those in the South, where only one major mountain range exists. In the year of record heavy snowfall for the area, all collared caribou wintered on windswept alpine slopes, while during the below average snowfall year, many caribou remained in forested habitats. In winter, caribou were found to forage on terrestrial lichens in both lowland lodgepole pine flats and on windswept alpine slopes, and on arboreal lichens in upper elevation Engelmann spruce and subalpine fir forests. There are at least 600-700 caribou in the Omineca Mountains.

The behaviour of radiocaesium in woodland ecosystems. Measurement and modelling

International Nuclear Information System (INIS)

Toal, M.

1999-02-01

In order to better quantify risk to non-human biota from environmental radioactivity, our understanding of the behaviour of radionuclides in the biosphere needs to be increased. Hence the aims of the present study were threefold: 1) Review Ecological Risk Assessment (ERA) methodologies, 2) Quantify radiocaesium distribution in woodland biota in the vicinity of BNFL Sellafield, 3) Use this information to develop radiocaesium food-chain and dosimetry models for terrestrial invertebrates and small-mammals. A review of ERA literature concluded that of the two main methodologies available (individual receptor and holistic ERA), individual receptor based analysis is the most credible method given in today's level of scientific understanding. lt was also concluded that the use of modelling techniques in ERA will increase in future years. Two study sites were sampled, a Picea sitchensis monoculture (Lady Wood) and a mixed deciduous site (Longrigg Wood). Mean levels of Cs-137 (all activities quoted in Bq/kg dry weight) in soils:leaf litter were 473:408 (Lady Wood) and 142:32 (Longrigg Wood). The activity of understorey vegetation varied with ranges of 17-508 and 4-48 Bq/kg in Lady Wood and Longrigg, respectively. No vegetation species had concentration ratios (CRs) > 1. The greatest range in Cs-137 activity (2-5242 Bq/kg DW, Lady Wood) was found in fungi, with Mycena galariculata and Hypholoma fasciculare attaining the highest biomagnifications (CRs = 2.6, 2.0 respectively). Due to radioanalytical constraints, only 'mixed invertebrate' samples were measured for Longrigg Wood (yearly average = 8.5 Bq/kg). No significant invertebrate body-burden differences were found between taxa or between seasons for each invertebrate group in Lady Wood. Mean yearly Cs-137 body-burdens (Bq/kg DW) were 94 (Diplopoda), 104 (Isopoda), 54 (Chilopoda), 120 (Araneae), 91 (Opilionidae) and 41 (Carabidae). No invertebrates had CRs > 1. Seasonal Cs-137 body-burdens were also measured for the

21 CFR 310.531 - Drug products containing active ingredients offered over-the-counter (OTC) for the treatment of...

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2010-04-01

..., juniper tar (oil of cade), lanolin, magnesium sulfate, menthol, methyl salicylate, oxyguinoline sulfate..., hexachlorophene, isobutamben, juniper tar (oil of cade), lanolin, magnesium sulfate, menthol, methyl salicylate...

Wildfire patterns and landscape changes in Mediterranean oak woodlands.

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Guiomar, N; Godinho, S; Fernandes, P M; Machado, R; Neves, N; Fernandes, J P

2015-12-01

Fire is infrequent in the oak woodlands of southern Portugal (montado) but large and severe fires affected these agro-forestry systems in 2003-2005. We hypothesised transition from forest to shrubland as a fire-driven process and investigated the links between fire incidence and montado change to other land cover types, particularly those related with the presence of pioneer communities (generically designed in this context as "transitions to early-successional communities"). We present a landscape-scale framework for assessing the probability of transition from montado to pioneer communities, considering three sets of explanatory variables: montado patterns in 1990 and prior changes from montado to early-successional communities (occurred between 1960 and 1990), fire patterns, and spatial factors. These three sets of factors captured 78.2% of the observed variability in the transitions from montado to pioneer vegetation. The contributions of fire patterns and spatial factors were high, respectively 60.6% and 43.4%, the influence of montado patterns and former changes in montado being lower (34.4%). The highest amount of explained variation in the occurrence of transitions from montado to early-successional communities was related to the pure effect of fire patterns (19.9%). Low spatial connectedness in montado landscape can increase vulnerability to changes, namely to pioneer vegetation, but the observed changes were mostly explained by fire characteristics and spatial factors. Among all metrics used to characterize fire patterns and extent, effective mesh size provided the best modelling results. Transitions from montado to pioneer communities are more likely in the presence of high values of the effective mesh size of total burned area. This cross-boundary metric is an indicator of the influence of large fires in the distribution of the identified transitions and, therefore, we conclude that the occurrence of large fires in montado increases its probability of

Estimation of readily-available phosphate in some English Lake District woodland soils

International Nuclear Information System (INIS)

Harrison, A.F.

1975-01-01

Four chemical extraction methods (2.5 percent acetic acid, Olsen, Truog and Egner) and 5 isotope dilution methods involving short exchange periods (1 inverse dilution, 2 carrier-free and 2 using phosphate carrier) were investigatd for reliability in measurement of readily-available phosphate in widely differing soils from some non-fertilized semi-natural Lake District woodlands. Correlation coefficients between values produced and phosphate uptake during a two-month period from 16 soils (pH range 3.85 to 7.85) by Urtica dioica L., a phosphate-sensitive plant, differed markedly. They were negative for all the extraction procedures, varying from r = -0.079 for the Truog method to -0.518 for the Olsen method. The isotope dilution methods, with the exception of one, all gave positive correlation coefficients, varying from r = -0.676 for the carrier-free method of Talibudeen to r = 0.798 for a modified Amer carrier method. When combined by multiple regression analysis, the results of the isotope dilution methods accounted for 86.4 percent of the variation in phosphate-uptake by the nettle plants, whereas the results of the four extraction methods accounted for only 32.2 percent. Multiple regression analysis of the data showed that there were strong and different interactions between all methods investigated and soil properties, particularly soil pH, organic matter content, extractable iron, C/P and C/N. This clearly indicates that methods must be evaluated for each series of soils to be compared. (author)

Lifetime return on investment increases with leaf lifespan among 10 Australian woodland species.

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Falster, Daniel S; Reich, Peter B; Ellsworth, David S; Wright, Ian J; Westoby, Mark; Oleksyn, Jacek; Lee, Tali D

2012-01-01

• Co-occurring species often differ in their leaf lifespan (LL) and it remains unclear how such variation is maintained in a competitive context. Here we test the hypothesis that leaves of long-LL species yield a greater return in carbon (C) fixed per unit C or nutrient invested by the plant than those of short-LL species. • For 10 sympatric woodland species, we assessed three-dimensional shoot architecture, canopy openness, leaf photosynthetic light response, leaf dark respiration and leaf construction costs across leaf age sequences. We then used the YPLANT model to estimate light interception and C revenue along the measured leaf age sequences. This was done under a series of simulations that incorporated the potential covariates of LL in an additive fashion. • Lifetime return in C fixed per unit C, N or P invested increased with LL in all simulations. • In contrast to other recent studies, our results show that extended LL confers a fundamental economic advantage by increasing a plant's return on investment in leaves. This suggests that time-discounting effects, that is, the compounding of income that arises from quick reinvestment of C revenue, are key in allowing short-LL species to succeed in the face of this economic handicap. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Continuous ammonium enrichment of a woodland stream: uptake kinetics, leaf decomposition, and nitrification

Energy Technology Data Exchange (ETDEWEB)

Newbold, J D; Elwood, J W; Schulze, M S; Stark, R W; Barmeier, J C

1983-01-01

In order to test for nitrogen limitation and examine ammonium uptake by stream sediments, ammonium hydroxide was added continuously at concentrations averaging 100 /sup +/gl/sup -1/ for 70 days to a second-order reach of Walker Branch, an undisturbed woodland stream in Tennessee. Ammonium uptake during the first 4 h of addition corresponded to adsorption kinetics rather than to first-order uptake or to Michaelis-Menten kinetics. However, the calculated adsorption partition coefficient was two to four orders of magnitude greater than values reported for physical adsorption of ammonium, suggesting that the uptake was largely biotic. Mass balance indicated that the uptake of ammonium from the water could be accounted for by increased nitrogen content in benthic organic detritus. Nitrification, inferred from longitudinal gradients in NO/sub 3/, began soon after enrichment and increased dramatically near the end of the experiment. Both ammonium and nitrate concentrations dropped quickly to near background levels when input ceased, indicating little desorption or nitrification of excess nitrogen stored in the reach. There was no evidence of nitrogen limitation as measured by weight loss, oxygen consumption, phosphorus content, and macroinvertebrate density of red oak leaf packs, or by chlorophyll content and aufwuchs biomass on plexiglass slides. A continuous phosphorus enrichment 1 year earlier had demonstrated phosphorus limitation in Walker Branch. 38 references, 6 figures, 3 tables.

Modeling the kinetics of essential oil hydrodistillation from juniper berries (Juniperus communis L. using non-linear regression

Directory of Open Access Journals (Sweden)

Radosavljević Dragana B.

2017-01-01

Full Text Available This paper presents kinetics modeling of essential oil hydrodistillation from juniper berries (Juniperus communis L. by using a non-linear regression methodology. The proposed model has the polynomial-logarithmic form. The initial equation of the proposed non-linear model is q = q∞•(a•(logt2 + b•logt + c and by substituting a1=q∞•a, b1 = q∞•b and c1 = q∞•c, the final equation is obtained as q = a1•(logt2 + b1•logt + c1. In this equation q is the quantity of the obtained oil at time t, while a1, b1 and c1 are parameters to be determined for each sample. From the final equation it can be seen that the key parameter q∞, which presents the maximal oil quantity obtained after infinite time, is already included in parameters a1, b1 and c1. In this way, experimental determination of this parameter is avoided. Using the proposed model with parameters obtained by regression, the values of oil hydrodistillation in time are calculated for each sample and compared to the experimental values. In addition, two kinetic models previously proposed in literature were applied to the same experimental results. The developed model provided better agreements with the experimental values than the two, generally accepted kinetic models of this process. The average values of error measures (RSS, RSE, AIC and MRPD obtained for our model (0.005; 0.017; –84.33; 1.65 were generally lower than the corresponding values of the other two models (0.025; 0.041; –53.20; 3.89 and (0.0035; 0.015; –86.83; 1.59. Also, parameter estimation for the proposed model was significantly simpler (maximum 2 iterations per sample using the non-linear regression than that for the existing models (maximum 9 iterations per sample. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-35026

The influence of vegetation on bird distribution in dry forests and oak woodlands of western Mexico

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Pablo Corcuera

2006-06-01

Full Text Available The bird species distribution along a dry forest-oak woodland vegetation gradient was studied in autumn and spring in two consecutive years. Intra-seasonal comparisons showed that bird species had similar distributions in each of the two years. Inter-seasonal changes were mainly due to compositional differences even though resident species generally used similar habitats in both seasons. Ordination analyses, based on the first year bird species abundances, showed a clearly segregated distribution between forest and woodland birds. Within these two vegetation types, the distribution tended to be more individualistic. Nevertheless further habitats could be identified according to groups of birds having similar distributions. These habitats did not correspond to the plant associations which resulted from a previous classification of the vegetation. Observations of the plant use by the birds during the study period showed that, in most cases, the plant variables associated with ordination analyses are unlikely to be very important for the bird species life cycles. Rev. Biol. Trop. 54(2: 657-672. Epub 2005 Jun 01.Se estudió la distribución de especies de aves a lo largo de un gradiente de vegetación bosque seco - bosque de encino en el otoño y primavera de dos años consecutivos. Las comparaciones intra-estacionales mostraron distribuciones similares de las especies de aves en ambos años. Los cambios inter-estacionales se debieron principalmente a diferencias en la composición, aunque las especies residentes normalmente usan hábitats similares en ambas estaciones. Los análisis de ordenación, basados en las abundancias de las aves en el primer año de muestreo, mostraron una distribución claramente segregada entre aves del bosque seco y del bosque de encino. Aunque la distribución de las especies fue más azarosa dentro de cada tipo de vegetación, se pudieron identificar ciertos hábitats en base a grupos de aves con distribuciones

Using ultrasound measurements of rump fat to assess nutritional condition of woodland caribou in northern British Columbia, Canada

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David D. Gustine

2007-04-01

Full Text Available Body reserves (fat and protein of cervids are important to the reproductive success of individuals, and therefore may limit productivity of populations. We used a portable ultrasound machine to measure thickness of rump fat for 39 woodland caribou (Rangifer tarandus caribou captured in the winters (January–February of 2003 and 2004. We compared thickness of rump fat between pregnant and non-pregnant individuals in the Besa-Prophet drainage of northern British Columbia, Canada. Thirty-eight of the 39 females captured in British Columbia were adults and 34 of the adult caribou were pregnant (89.5 ± 5.1%, x– ± binomial SE. Pregnant individuals had more rump fat (0.60 ± 0.067 cm than nonpregnant animals (0.20 ± 0.029 cm. Recognizing that deposition and mobilization of fat vary with age and possibly across the winter season, ultrasonography can be used as a non-invasive technique in the field to assist in estimating body fat of caribou.

Historical ecology meets conservation and evolutionary genetics: a secondary contact zone between Carabus violaceus (Coleoptera, Carabidae populations inhabiting ancient and recent woodlands in north-western Germany

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Andrea Matern

2011-05-01

Full Text Available Only very few cases have documented that an increase in connectivity after a period of fragmentation in ecological time has had an effect on the distribution, genetic structure and morphology of stenotopic species. In this study we present an example of clinal variability in a woodland ground beetle as a result of changes in the connectivity of a landscape during the last two centuries. The study area hosts both the nominate form C. violaceus s. str. and the subspecies C. v. purpurascens, which is ranked as a distinct species by some authors. We studied 12 Carabus violaceus populations from a 30 km transect of ancient and recent forests in north-western Germany. We analyzed three polymorphic enzyme loci, classified the elytron sculpture and measured the shape of the aedeagus tip of the specimens. C. violaceus showed secondary gradients both in allozyme markers and morphometric characters in our study area. A genetic differentiation of 16% between the populations is high but lies within the range of intraspecific variability in habitat specialists of the genus Carabus. Populations had no significant deficit of heterozygotes. We found many hybrid populations in terms of morphological properties. This study highlights the conservation value of ancient woodland and the consequences of landscape connectivity and defragmentation on the genetic setting of a ground beetle. Moreover, it shows that differences in the external shape of male genitalia do not prevent gene flow within the genus Carabus. Thus, the establishment of species status should not exclusively be based on this property.

Relationship Between Mycorrhizal Associations and Tree Phyto-Sanitary Conditions of Urban Woodlands of Bogota D.C., Colombia

International Nuclear Information System (INIS)

Ramos Montano, Carolina; Posada Almanza, Raul H; Ronderos Figueroa, Miguel A; Penagos Canon, Gustavo A

2010-01-01

Spore number and root infection by Arbuscular mycorrhizal fungi were evaluated in Eugenia myrtifolia, Ficus soatensis and Croton bogotensis, in parks and green zones of urban woodlands of Bogota D.C, Colombia. The aim was to investigate relations between mycorrhizal associations and tree phyto-sanitary conditions, and effects of two distinct climatic zones. It was demonstrated that plant species and climate are significant sources of variations in the general mycorrhizal state. Eugenia myrtifolia showed the highest degree of root colonization but the lowest number of spores, while C. bogotensis had the opposite response. In general, dry environments favored the mycorrhizal infection levels. By considering overall data, there was a positive relation between the general phytosanitary status of the urban trees and the mycorrhizal colonization. The evaluation of the relationship with the incidence of specific foliar symptoms showed that chlorosis, bight and herbivory maintained a negative relation with the mycorrhization in E. myrtifolia and C. bogotensis. Results suggest that association with AM fungi helps in any way for reducing

The role of small woodland remnants on ground dwelling insect conservation in Chaco Serrano, Central Argentina.

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Moreno, María Laura; Fernández, María Guadalupe; Molina, Silvia Itati; Valladares, Graciela

2013-01-01

Many terrestrial ecosystems are changing due to extensive land use and habitat fragmentation, posing a major threat to biodiversity. In this study, the effects of patch size, isolation, and edge/interior localization on the ground dwelling insect communities in the Chaco Serrano woodland remnants in central Argentina were examined. Sampling was carried out in December 2003 and March 2004 in nine remnants (0.57 to 1000 hectares) using pitfall traps. In total, 7071 individuals representing 12 orders and 79 families were recorded. The taxonomic composition of these communities was linked to remnant size. Insect abundance increased (as did their richness, albeit marginally) as remnant area decreased, with no significant effects of isolation or edge/interior localization on abundance, richness, or diversity. No differential area effects were observed when abundance and richness of predators, scavengers, and herbivores were compared. Thus, ground insect communities in fragmented Chaco Serrano seem to respond mainly to patch level, rather than to within-patch (edge effects) or landscape (isolation) level variables. These results suggest that small Chaco Serrano remnants, by supporting larger ground-dwelling insect assemblages, may play an important role from a conservation viewpoint.

Afforestation of Boreal Open Woodlands: Early Performance and Ecophysiology of Planted Black Spruce Seedlings

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Daniel Lord

2013-06-01

Full Text Available Open lichen woodlands (LWs are degraded stands that lack the ability to regenerate naturally due to a succession of natural and/or anthropogenic disturbances. As they represent both interesting forest restoration and carbon sequestration opportunities, we tested disc scarification and planting of two sizes of containerized black spruce (Picea mariana Mill. (BSP seedlings for their afforestation. We compared treatment of unproductive LWs to reforestation of harvested, closed-crown black spruce-feathermoss (BSFM stands. After one year, seedling survival and nutritional status were equivalent among stand types but despite higher root elongation index (REI, planted seedlings in LWs had lower relative growth rate, smaller total biomass and stem diameter than those in BSFM stands. Soil fertility variables, soil temperature, nor seedling water potential, helped at explaining this early growth response. Disc scarification significantly improved seedling first-year survival, biomass and foliar nutrient concentrations of P, Ca, and Mg. Smaller planting stock showed higher REI, higher shoot water potential, and higher foliar nutrient concentration of all but one of the measured nutrients (N, P, K and Mg. Hence, preliminary results suggest that planting of smaller containerized black spruce stock, combined with disc scarification, shows potential for afforestation of unproductive LWs. The impact of the lichen mat and other potential growth limiting factors on afforestation of these sites requires further investigation.

Local climatic conditions constrain soil yeast diversity patterns in Mediterranean forests, woodlands and scrub biome.

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Yurkov, Andrey M; Röhl, Oliver; Pontes, Ana; Carvalho, Cláudia; Maldonado, Cristina; Sampaio, José Paulo

2016-02-01

Soil yeasts represent a poorly known fraction of the soil microbiome due to limited ecological surveys. Here, we provide the first comprehensive inventory of cultivable soil yeasts in a Mediterranean ecosystem, which is the leading biodiversity hotspot for vascular plants and vertebrates in Europe. We isolated and identified soil yeasts from forested sites of Serra da Arrábida Natural Park (Portugal), representing the Mediterranean forests, woodlands and scrub biome. Both cultivation experiments and the subsequent species richness estimations suggest the highest species richness values reported to date, resulting in a total of 57 and 80 yeast taxa, respectively. These values far exceed those reported for other forest soils in Europe. Furthermore, we assessed the response of yeast diversity to microclimatic environmental factors in biotopes composed of the same plant species but showing a gradual change from humid broadleaf forests to dry maquis. We observed that forest properties constrained by precipitation level had strong impact on yeast diversity and on community structure and lower precipitation resulted in an increased number of rare species and decreased evenness values. In conclusion, the structure of soil yeast communities mirrors the environmental factors that affect aboveground phytocenoses, aboveground biomass and plant projective cover. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of declining oak vitality on ecosystem functions: Lessons from a Spanish oak woodland

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López-Sánchez, Aida; Bareth, Georg; Bolten, Andreas; Linstädter, Anja

2017-04-01

Mediterranean oak woodlands have a great ecological and socio-economic importance. Today, these fragile ecosystems are facing unprecedented degradation threats from Novel Oak Diseases (NODs). Among NOD drivers, maladapted land management practices and climate change are most important. Although it is generally believed that NOD-related declines in tree vitality will have detrimental effects on ecosystem functions, little is known on the magnitude of change, and whether different functions are affected in a similar way. Here we analyzed effects of tree vitality on various ecosystem functions, comparing subcanopy and intercanopy habitats across two oak species (Quercus ilex and Q. suber) in a Spanish oak woodland. We asked how functions - including aboveground net primary productivity (ANPP), taxonomic diversity, and litter decomposition rates - were affected by oak trees' size and vitality. We also combined measurements in the ecosystem function habitat index (MEFHI), a proxy of ecosystem multifunctionality. Field research was carried out in 2016 on a dehesa in southern Spain. We used a stratified random sampling to contrast trees of different species affiliation, size and vitality. Tree vitality was estimated as crown density (assessed via hemispherical photography), and as tree vigor, which combines the grade of canopy defoliation with proxies for tree size (dbh, height, crown height and crown radius). For each tree (n = 34), two plots (50 x 50 cm) were located; one in the subcanopy habitat, and the other in the intercanopy area beyond the tree crown's influence. On all 68 plots, moveable cages were placed during the main growth period (March to May) to estimate ANPP under grazed conditions. Litter decomposition rates were assessed via the tea bag index. ANPP and the biomass of grasses, forbs and legumes were recorded via destructive sampling. To take plots' highly variable environmental conditions into account, we recorded a suite of abiotic and biotic

Evaluating nurse plants for restoring native woody species to degraded subtropical woodlands.

Science.gov (United States)

Yelenik, Stephanie G; DiManno, Nicole; D'Antonio, Carla M

2015-01-01

Harsh habitats dominated by invasive species are difficult to restore. Invasive grasses in arid environments slow succession toward more desired composition, yet grass removal exacerbates high light and temperature, making the use of "nurse plants" an appealing strategy. In this study of degraded subtropical woodlands dominated by alien grasses in Hawai'i, we evaluated whether individuals of two native (Dodonaea viscosa, Leptocophylla tameiameia) and one non-native (Morella faya) woody species (1) act as natural nodes of recruitment for native woody species and (2) can be used to enhance survivorship of outplanted native woody species. To address these questions, we quantified the presence and persistence of seedlings naturally recruiting beneath adult nurse shrubs and compared survival and growth of experimentally outplanted seedlings of seven native woody species under the nurse species compared to intact and cleared alien-grass plots. We found that the two native nurse shrubs recruit their own offspring, but do not act as establishment nodes for other species. Morella faya recruited even fewer seedlings than native shrubs. Thus, outplanting will be necessary to increase abundance and diversity of native woody species. Outplant survival was the highest under shrubs compared to away from them with few differences between nurse species. The worst habitat for native seedling survival and growth was within the unmanaged invasive grass matrix. Although the two native nurse species did not differentially affect outplant survival, D. viscosa is the most widespread and easily propagated and is thus more likely to be useful as an initial nurse species. The outplanted species showed variable responses to nurse habitats that we attribute to resource requirements resulting from their typical successional stage and nitrogen fixation capability.

Ground Juniperus pinchotii and urea in supplements fed to Rambouillet ewe lambs Part 2: Ewe lamb rumen microbial communities.

Science.gov (United States)

Ishaq, S L; Yeoman, C J; Whitney, T R

2017-10-01

This study evaluated effects of ground redberry juniper () and urea in dried distillers grains with solubles-based supplements fed to Rambouillet ewe lambs ( = 48) on rumen physiological parameters and bacterial diversity. In a randomized study (40 d), individually-penned lambs were fed ground sorghum-sudangrass hay and of 1 of 8 supplements (6 lambs/treatment; 533 g/d; as-fed basis) in a 4 × 2 factorial design with 4 concentrations of ground juniper (15%, 30%, 45%, or 60% of DM) and 2 levels of urea (1% or 3% of DM). Increasing juniper resulted in minor changes in microbial β-diversity (PERMANOVA, pseudo F = 1.33, = 0.04); however, concentrations of urea did not show detectable broad-scale differences at phylum, family, or genus levels according to ANOSIM ( > 0.05), AMOVA ( > 0.10), and PERMANOVA ( > 0.05). Linear discriminant analysis indicated some genera were specific to certain dietary treatments ( < 0.05), though none of these genera were present in high abundance; high concentrations of juniper were associated with and , low concentrations of urea were associated with , and high concentrations of urea were associated with and . were decreased by juniper and urea. , , and increased with juniper and were positively correlated (Spearman's, < 0.05) with each other but not to rumen factors, suggesting a symbiotic interaction. Overall, there was not a juniper × urea interaction for total VFA, VFA by concentration or percent total, pH, or ammonia ( 0.29). When considering only percent inclusion of juniper, ruminal pH and proportion of acetic acid linearly increased ( < 0.001) and percentage of butyric acid linearly decreased ( = 0.009). Lamb ADG and G:F were positively correlated with (Spearman's, < 0.05) and negatively correlated with Synergistaceae, the BS5 group, and Lentisphaerae. Firmicutes were negatively correlated with serum urea nitrogen, ammonia, total VFA, total acetate, and total propionate. Overall, modest differences in bacterial diversity among

Transition from Connected to Fragmented Vegetation across an Environmental Gradient: Scaling Laws in Ecotone Geometry.

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Gastner, Michael T; Oborny, Beata; Zimmermann, D K; Pruessner, Gunnar

2009-07-01

A change in the environmental conditions across space-for example, altitude or latitude-can cause significant changes in the density of a vegetation type and, consequently, in spatial connectivity. We use spatially explicit simulations to study the transition from connected to fragmented vegetation. A static (gradient percolation) model is compared to dynamic (gradient contact process) models. Connectivity is characterized from the perspective of various species that use this vegetation type for habitat and differ in dispersal or migration range, that is, "step length" across the landscape. The boundary of connected vegetation delineated by a particular step length is termed the " hull edge." We found that for every step length and for every gradient, the hull edge is a fractal with dimension 7/4. The result is the same for different spatial models, suggesting that there are universal laws in ecotone geometry. To demonstrate that the model is applicable to real data, a hull edge of fractal dimension 7/4 is shown on a satellite image of a piñon-juniper woodland on a hillside. We propose to use the hull edge to define the boundary of a vegetation type unambiguously. This offers a new tool for detecting a shift of the boundary due to a climate change.

A War of Words: Do Conflict Metaphors Affect Beliefs about Managing “Unwanted” Plants?

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Cameron G. Nay

2013-03-01

Full Text Available Woody plants have increased in density and extent in rangelands worldwide since the 1800s, and land managers increasingly remove woodland plants in hopes of restoring pre-settlement conditions and/or improved forage for grazing livestock. Because such efforts can be controversial, especially on publicly owned lands, managers often attempt to frame issues in ways they believe can improve public acceptance of proposed actions. Frequently these framing efforts employ conflict metaphors drawn from military or legal lexicons. We surveyed citizens in the Rocky Mountains region, USA, about their beliefs concerning tree-removal as a management strategy. Plants targeted for removal in the region include such iconic tree species as Douglas-fir and ponderosa pine as well as other less-valued species, such as Rocky Mountain juniper, that are common targets for removal nationwide. To test the influence of issue frame on acceptance, recipients were randomly assigned surveys in which the reason for conifer removal was described using one of three terms often employed by invasive biologists and land managers: “invasion”, “expansion”, and “encroachment”. Framing in this instance had little effect on responses. We conclude the use of single-word frames by scientists and managers use to contextualize an issue may not resonate with the public.

Radiocarbon dating of large termite mounds of the miombo woodland of Katanga, DR Congo

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Erens, Hans; Boudin, Mathieu; Mees, Florias; Dumon, Mathijs; Mujinya, Basile; Van Strydonck, Mark; Baert, Geert; Boeckx, Pascal; Van Ranst, Eric

2015-04-01

The miombo woodlands of South Katanga (D.R. Congo) are characterized by a high spatial density of large conic termite mounds built by Macrotermes falciger (3 to 5 ha-1, ~5 m high, ~15 m in diameter). The time it takes for these mounds to attain this size is still largely unknown. In this study, the age of four of these mounds is determined by 14C-dating the acid-insoluble organic carbon fraction of samples taken along the central vertical axis of two active and two abandoned mounds. The age sequence in the active mounds is erratic, but the results for the abandoned mounds show a logical increase of 14C-age with depth. The ages measured at 50 cm above ground level were 2335 - 2119 cal yr BP for the large abandoned mound (630 cm high), and 796 - 684 cal yr BP for the small abandoned mound (320 cm high). Cold-water-extractable organic carbon (CWEOC) measurements combined with spectroscopic analysis revealed that the lower parts of the active mounds may have been contaminated with recent carbon that leached from the active nest. Nonetheless, this method appears to provide reliable age estimates of large, abandoned termite mounds, which are older than previously estimated. Furthermore, historical mound growth rates seem to correspond to past temperature changes, suggesting a relation between past environmental conditions and mound occupancy. Keywords : 14C, water-extractable carbon, low-temperature combustion

Habitat Fragmentation Handbook for Installation Planners: Status and Options

Science.gov (United States)

2006-12-01

slippery elm , sycamore, American elm , black walnut, eastern redbud, and American basswood, • Species composition of herbaceous vegetation of poison ivy...water source (creek, draw, spring, seep). The mature ash juniper stand can include oaks, ashs, elms , or wal- nuts. A juniper/deciduous mix of varying

Evaluating nurse plants for restoring native woody species to degraded subtropical woodlands

Science.gov (United States)

Yelenik, Stephanie G.; DiManno, Nicole; D’Antonio, Carla M.

2015-01-01

Harsh habitats dominated by invasive species are difficult to restore. Invasive grasses in arid environments slow succession toward more desired composition, yet grass removal exacerbates high light and temperature, making the use of “nurse plants” an appealing strategy. In this study of degraded subtropical woodlands dominated by alien grasses in Hawai'i, we evaluated whether individuals of two native (Dodonaea viscosa, Leptocophylla tameiameia) and one non-native (Morella faya) woody species (1) act as natural nodes of recruitment for native woody species and (2) can be used to enhance survivorship of outplanted native woody species. To address these questions, we quantified the presence and persistence of seedlings naturally recruiting beneath adult nurse shrubs and compared survival and growth of experimentally outplanted seedlings of seven native woody species under the nurse species compared to intact and cleared alien-grass plots. We found that the two native nurse shrubs recruit their own offspring, but do not act as establishment nodes for other species. Morella faya recruited even fewer seedlings than native shrubs. Thus, outplanting will be necessary to increase abundance and diversity of native woody species. Outplant survival was the highest under shrubs compared to away from them with few differences between nurse species. The worst habitat for native seedling survival and growth was within the unmanaged invasive grass matrix. Although the two native nurse species did not differentially affect outplant survival, D. viscosa is the most widespread and easily propagated and is thus more likely to be useful as an initial nurse species. The outplanted species showed variable responses to nurse habitats that we attribute to resource requirements resulting from their typical successional stage and nitrogen fixation capability.

76 FR 6775 - Combined Notice of Filings #1

Science.gov (United States)

2011-02-08

... Wind Power LLC; Hay Canyon Wind LLC; Juniper Canyon Wind Power LLC; Klamath Energy LLC; Klamath... Energy V LLC; Vantage Wind Energy LLC; White Oak Energy LLC. Description: Generation Site Report Fourth..., LLC; Hardscrabble Wind Power LLC; Hay Canyon Wind LLC; Juniper Canyon Wind Power LLC; Klamath Energy...

{delta}{sup 13}C in Tibetan juniper trees - climate trends through the past 1600 years; {delta}{sup 13}C in tibetischen Wacholdern - Klimaentwicklung der letzten 1600 Jahre

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, B.

1998-09-01

A {delta}{sup 13}C{sub Zell}-chronology of juniper tree cellulose from the upper treeline covering the last 1600 years was set up. The tree site is situated close to Qamdo in southeast Tibet at an altitude of 4350 m a.s.l. The southwest slope gets rain during the Indian summer monsoon. Ten trees have been sampled either by coring or by cutting of trunc-sections in pentad sampling interval. Three trees were analysed in two different radial directions. The very positive {delta}{sup 13}C{sub Zell}-data generally varying around -18,75 permille show the typical low fractionation of high mountain plants. Different interpretations are suggested for data before and after 1800 A.D. (orig.) [Deutsch] An Zellulose von Wacholdern der oberen Waldgrenze in Suedost-Tibet wurde eine 1600-jaehrige {delta}{sup 13}C{sub Zell}-Chronologie aufgestellt. Der Standort liegt in 4350 m ue.M. in der Naehe von Qamdo, ist nach Suedwest geneigt und erhaelt Niederschlaege in den Sommermonaten durch den Indischen-Suedwest-Monsun. Zehn Baeume wurden anhand von Kernen und Stammscheiben in Abschnitten von fuenf Jahren beprobt. An drei Baeumen konnten zwei Segmente desselben Baumes untersucht werden. Die im Mittel sehr positiven {delta}{sup 13}C{sub Zell}-Daten um -18,75 permille deuten auf eine fuer Hochgebirgspflanzen typische geringere Fraktionierung hin. Unterschiedliche Interpretationswege werden fuer die Daten vor und nach 1800 verfolgt. (orig.)

Untangling the primary drivers of pinyon monoterpene production and emissions under predicted drought

Science.gov (United States)

Trowbridge, A. M.; Adams, H. D.; Breshears, D. D.; Monson, R. K.

2012-04-01

Climate and insect herbivory have important consequences for plant function, atmospheric composition, and the functioning of ecosystems and ecological communities. Within the last decade, pinyon-juniper woodlands throughout the southwestern U.S. have suffered large-scale mortality, especially of pinyon pine, due to drought and associated insect outbreaks. While much research has focused on the primary metabolic mechanisms underlying pinyon's sensitivity to drought, there remains a gap in our knowledge concerning how the resulting shift in carbon allocation toward plant secondary compounds, particularly monoterpenes, affects atmospheric process and ecological interactions. Monoterpenes are the principal constituents of pinyon resin. Because of their large global emission rates and effect on atmospheric chemistry, particularly ozone creation, identifying controls over emissions and sensitivities to environmental change is critical for global emission models. Furthermore, monoterpenes are known to impact insect behavior and act as defense compounds against herbivores, contributing to insect population fluctuations either directly through toxicity, or indirectly by influencing parasitism susceptibility. Pinyon mortality events are thought to be exacerbated by their susceptibility to herbivores resulting from weakened secondary chemical defenses, but the impact of current and predicted drought on the chemical defense status of pinyons and subsequent atmospheric and ecological consequences remain unknown. A field study was developed to examine the impact of seasonality and climate, particularly drought, on pinyon pine physiology and chemistry in the context of tiger moth (Lophocampa ingens) herbivory in pinyon-juniper woodlands. We demonstrate the importance of geography and seasonality, particularly mid-summer drought and late summer monsoons, in driving physiology and monoterpene concentrations and emissions. Emission rates significantly decreased throughout the summer

Influence of tree canopy on N{sub 2} fixation by pasture legumes and soil rhizobial abundance in Mediterranean oak woodlands

Energy Technology Data Exchange (ETDEWEB)

Carranca, C., E-mail: corina.carranca@iniav.pt [INIAV, Qta Marquês, 2784-505 Oeiras (Portugal); Castro, I.V.; Figueiredo, N. [INIAV, Qta Marquês, 2784-505 Oeiras (Portugal); Redondo, R. [Laboratorio de Isotopos Estables, Universidade Autonoma, Madrid (Spain); Rodrigues, A.R.F. [Centro de Estudos Florestais, ISA/UL, Tapada Ajuda, 1349-017 Lisboa (Portugal); Saraiva, I.; Maricato, R. [INIAV, Qta Marquês, 2784-505 Oeiras (Portugal); Madeira, M.A.V. [Centro de Estudos Florestais, ISA/UL, Tapada Ajuda, 1349-017 Lisboa (Portugal)

2015-02-15

Symbiotic N{sub 2} fixation is of primordial significance in sustainable agro-forestry management as it allows reducing the use of mineral N in the production of mixed stands and by protecting the soils from degradation. Thereby, on a 2-year basis, N{sub 2} fixation was evaluated in four oak woodlands under Mediterranean conditions using a split-plot design and three replicates. {sup 15}N technique was used for determination of N{sub 2} fixation rate. Variations in environmental conditions (temperature, rainfall, radiation) by the cork tree canopy as well as the age of stands and pasture management can cause great differences in vegetation growth, legume N{sub 2} fixation, and soil rhizobial abundance. In the present study, non-legumes dominated the swards, in particular beneath the tree canopy, and legumes represented only 42% of total herbage. A 2-fold biomass reduction was observed in the oldest sown pasture in relation to the medium-age sward (6 t DW ha{sup −1} yr{sup −1}). Overall, competition of pasture growth for light was negligible, but soil rhizobial abundance and symbiotic N{sub 2} fixation capacity were highly favored by this environmental factor in the spring and outside the influence of tree canopy. Nitrogen derived from the atmosphere was moderate to high (54–72%) in unsown and sown swards. Inputs of fixed N2 increased from winter to spring due to more favorable climatic conditions (temperature and light intensity) for both rhizobia and vegetation growths. Assuming a constant fixation rate at each seasonal period, N{sub 2} fixation capacity increased from about 0.10 kg N ha{sup −1} per day in the autumn–winter period to 0.15 kg N ha{sup −1} per day in spring. Belowground plant material contributed to 11% of accumulated N in pasture legumes and was not affected by canopy. Size of soil fixing bacteria contributed little to explain pasture legumes N. - Highlights: • Legumes fixation in oak woodlands was quantified in terms of biomass and N

A numerical simulation on the flow of watershed filtration reactors using lignocellulosic materials

Science.gov (United States)

N. Hur; B. Choi; J.S. Han; E.W. Shin; S. Min; R.M. Rowell

2003-01-01

Pinyon juniper, a small-diameter and underutilized (SDU) lignocellulosic material, was harvested in New Mexico, identified as Juniperus monosperma at the USDA Forest Products Laboratory, chipped, fiberized and chemically modified to remove pollutants from wastewater. This juniper species was selected as a raw material through screening test for removal of pollutants...

Disentangling woodland caribou movements in response to clearcuts and roads across temporal scales.

Directory of Open Access Journals (Sweden)

David Beauchesne

Full Text Available Although prey species typically respond to the most limiting factors at coarse spatiotemporal scales while addressing biological requirements at finer scales, such behaviour may become challenging for species inhabiting human altered landscapes. We investigated how woodland caribou, a threatened species inhabiting North-American boreal forests, modified their fine-scale movements when confronted with forest management features (i.e. clearcuts and roads. We used GPS telemetry data collected between 2004 and 2010 on 49 female caribou in a managed area in Québec, Canada. Movements were studied using a use--availability design contrasting observed steps (i.e. line connecting two consecutive locations with random steps (i.e. proxy of immediate habitat availability. Although caribou mostly avoided disturbances, individuals nonetheless modulated their fine-scale response to disturbances on a daily and annual basis, potentially compromising between risk avoidance in periods of higher vulnerability (i.e. calving, early and late winter during the day and foraging activities in periods of higher energy requirements (i.e. spring, summer and rut during dusk/dawn and at night. The local context in which females moved was shown to influence their decision to cross clearcut edges and roads. Indeed, although females typically avoided crossing clearcut edges and roads at low densities, crossing rates were found to rapidly increase in greater disturbance densities. In some instance, however, females were less likely to cross edges and roads as densities increased. Females may then be trapped and forced to use disturbed habitats, known to be associated with higher predation risk. We believe that further increases in anthropogenic disturbances could exacerbate such behavioural responses and ultimately lead to population level consequences.

Disentangling woodland caribou movements in response to clearcuts and roads across temporal scales.

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Beauchesne, David; Jaeger, Jochen Ag; St-Laurent, Martin-Hugues

2013-01-01

Although prey species typically respond to the most limiting factors at coarse spatiotemporal scales while addressing biological requirements at finer scales, such behaviour may become challenging for species inhabiting human altered landscapes. We investigated how woodland caribou, a threatened species inhabiting North-American boreal forests, modified their fine-scale movements when confronted with forest management features (i.e. clearcuts and roads). We used GPS telemetry data collected between 2004 and 2010 on 49 female caribou in a managed area in Québec, Canada. Movements were studied using a use--availability design contrasting observed steps (i.e. line connecting two consecutive locations) with random steps (i.e. proxy of immediate habitat availability). Although caribou mostly avoided disturbances, individuals nonetheless modulated their fine-scale response to disturbances on a daily and annual basis, potentially compromising between risk avoidance in periods of higher vulnerability (i.e. calving, early and late winter) during the day and foraging activities in periods of higher energy requirements (i.e. spring, summer and rut) during dusk/dawn and at night. The local context in which females moved was shown to influence their decision to cross clearcut edges and roads. Indeed, although females typically avoided crossing clearcut edges and roads at low densities, crossing rates were found to rapidly increase in greater disturbance densities. In some instance, however, females were less likely to cross edges and roads as densities increased. Females may then be trapped and forced to use disturbed habitats, known to be associated with higher predation risk. We believe that further increases in anthropogenic disturbances could exacerbate such behavioural responses and ultimately lead to population level consequences.

Warming combined with more extreme precipitation regimes modifies the water sources used by trees.

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Grossiord, Charlotte; Sevanto, Sanna; Dawson, Todd E; Adams, Henry D; Collins, Adam D; Dickman, Lee T; Newman, Brent D; Stockton, Elizabeth A; McDowell, Nate G

2017-01-01

The persistence of vegetation under climate change will depend on a plant's capacity to exploit water resources. We analyzed water source dynamics in piñon pine and juniper trees subjected to precipitation reduction, atmospheric warming, and to both simultaneously. Piñon and juniper exhibited different and opposite shifts in water uptake depth in response to experimental stress and background climate over 3 yr. During a dry summer, juniper responded to warming with a shift to shallow water sources, whereas piñon pine responded to precipitation reduction with a shift to deeper sources in autumn. In normal and wet summers, both species responded to precipitation reduction, but juniper increased deep water uptake and piñon increased shallow water uptake. Shifts in the utilization of water sources were associated with reduced stomatal conductance and photosynthesis, suggesting that belowground compensation in response to warming and water reduction did not alleviate stress impacts for gas exchange. We have demonstrated that predicted climate change could modify water sources of trees. Warming impairs juniper uptake of deep sources during extended dry periods. Precipitation reduction alters the uptake of shallow sources following extended droughts for piñon. Shifts in water sources may not compensate for climate change impacts on tree physiology. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Vegetation characteristics of forest stands used by woodland caribou and those disturbed by fire or logging in Manitoba

Directory of Open Access Journals (Sweden)

Juha M. Metsaranta

2003-04-01

Full Text Available This study examined woodland caribou (Rangifer tarandus caribou in an area known as the Kississing-Naosap caribou range in west central Manitoba. The vegetation characteristics of areas used by caribou and areas disturbed by fire or logging were measured in order to develop a model to estimate habitat quality from parameters collected during stan¬dard resource inventories. There was evidence that habitat index values calculated using a visual score-sheet index could be used as the basis to relate parameters commonly collected during resource inventories to habitat suitability. Use of this model to select long and short-term leave areas during forest management planning could potentially mitigate some of the negative impacts of forest harvesting. Abundance of arboreal lichen and wind-fallen trees were important predictor variables in the suitability model, but their inclusion did not explain more variance in habitat suitability than models that did not include them. Extreme post-fire deadfall abundance may play a role in predator-prey dynamics by creating habitat that is equally unsuitable for all ungulates, and thus keeping both moose and caribou densities low.

Examining the Resilience of Crop Production, Livestock Carrying Capacity, and Woodland Density in a Rural Zimbabwean Socio-Ecological System Using Agent-Based Models Representing Human Management Decisions

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Eitzel Solera, M. V.; Neves, K.; Veski, A.; Solera, J.; Omoju, O. E.; Mawere Ndlovu, A.; Wilson, K.

2016-12-01

As climate change increases the pressures on arid ecosystems by changing timing and amount of rainfall, understanding the ways in which human management choices affect the resilience of these systems becomes key to their sustainability. On marginal farmland in Mazvihwa, Midlands Province, the historical carrying capacity of livestock has been consistently surprisingly high. We explore this phenomenon by building an agent-based model in NetLogo from a wealth of long-term data generated by the community-based participatory research team of The Muonde Trust, a Zimbabwean non-governmental organization. We combine the accumulated results of 35 years of indigenous and local knowledge with national datasets such as rainfall records. What factors keep the carrying capacity high? What management choices can maintain crops, livestock, and woodland at levels necessary for the community's survival? How do these choices affect long-term sustainability, and does increasing resilience at one scale reduce resilience at another scale? We use our agent-based model to explore the feedbacks between crops, livestock, and woodland and the impacts of various human choices as well as temporal and spatial ecological variation. By testing different scenarios, we disentangle the complex interactions between these components. We find that some factors out of the community's control can strongly affect the sustainability of the system through times of drought, and that supplementary feed may maintain livestock potentially at the expense of other resources. The challenges to resilience encountered by the farmers in Mazvihwa are not unique - many indigenous and rural people face drought and the legacies of colonialism, which contribute to lowered resilience to external challenges such as climate change, epidemics, and political instability. Using the agent-based model as a tool for synthesis and exploration initiates discussion about resilience-enhancing management choices for Mazvihwa's farmer-researchers.

Identifying factors linked to the occurrence of alien gastropods in isolated woodland water bodies

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Spyra, Aneta; Strzelec, Małgorzata

2014-03-01

Biological invasions are a significant component of human-caused global change and is widely regarded as one of the main threats to natural biodiversity. Isolated anthropogenic water bodies created in the areas that are deprived of natural freshwater habitats allow the survival and reproduction of alien species on newly settled sites. They are often small with water level fluctuations causing frequent environmental disturbances. The colonisation success may be the result of the rate of their degradation. The aims of the study were to determine the environmental conditions that affect the existence of alien species of gastropods in this type of aquatic environment and to examine whether the occurrence of non-native species affects the community structure of the native species. This study made it possible to group woodland ponds according to the occurrence of the three invasive species in snail communities and discuss the environmental conditions present in these pond types. Analysis of water properties emphasised the distinctiveness of the selected pond types. In ponds of the Potamopyrgus antipodarum type, we found the highest values of some parameters mainly hardness, conductivity, and content of calcium and chlorides, in contrast with the Physella acuta type, which were characterised by the lowest values except for phosphates and nitrites. In the Ferrissia fragilis type, we found the highest nitrate content. Data on the occurrence of alien species in different water environments play an important role in actions which are taken to prevent new invasions and spread of non-native species as well as to reduce future impacts of invaders.

Disruptive coloration in woodland camouflage: evaluation of camouflage effectiveness due to minor disruptive patches

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Selj, Gorm K.; Heinrich, Daniela H.

2016-10-01

We present results from an observer based photosimulation study of generic camouflage patterns, intended for military uniforms, where three near-identical patterns have been compared. All the patterns were prepared with similar effective color, but were different in how the individual pattern patches were distributed throughout the target. We did this in order to test if high contrast (black) patches along the outline of the target would enhance the survivability when exposed to human observers. In the recent years it has been shown that disruptive coloration in the form of high contrast patches are capable of disturbing an observer by creating false edges of the target and consequently enhance target survivability. This effect has been shown in different forms in the Animal Kingdom, but not to the same extent in camouflaged military targets. The three patterns in this study were i) with no disruptive preference, ii) with a disruptive patch along the outline of the head and iii) with a disruptive patch on the outline of one of the shoulders. We used a high number of human observers to assess the three targets in 16 natural (woodland) backgrounds by showing images of one of the targets at the time on a high definition pc screen. We found that the two patterns that were thought to have a minor disruptive preference to the remaining pattern were more difficult to detect in some (though not all) of the 16 scenes and were also better in overall performance when all the scenes were accounted for.

Woodland diagnosis of ecological reserve "Cerro de Amalucan" in the City of Puebla, México

Directory of Open Access Journals (Sweden)

Francisco Domínguez Hernández

2016-12-01

Full Text Available Trees in urban parks play a key role in the sustainability of cities. The tree is urban landscape of a city, provides environmental, aesthetic, scenic, recreational, cultural and economic benefits. The obwas to study the current state of woodland in the Cerro de Amalucan Ecological Reserve in the city of Puebla, Mexico, a forest dasometric diagnosis was applied by sampling in the area. Settling 17 sampling sites area of 1000 m2, completely randomized design with dasometric data. The results were averaged 183.5 trees per hectare, the most dominant Eucalyptus sp with 61.5% of actual stocks species. Following the species Cupressus lindleyi with 22.2%. Subsequently, the species Juniperus deppeana, with 6.8%, and the species Ipomoea murocoides, which had 2.9% of the total population, like the species polystachya Eysenhardtia, continuing the species flaccid Juniperus, with 1.6%, followed Cupressus sempervirens with 0.96%, Casuarina equisetifolia, with 0.64%, finally Pinus patula with 0.64%. Are cataloged as exotic tree species the next in line: Eucalyptus sp, and Casuarina equisetifolia, Cupressus lindleyi, Cupressus semprevirens and Pinus patula and were characterized as native species: Juniperus deppeana Eysenhardtia polystachya, Juniperus flacida. The areas are to manage 20 hectares with reforestation for restoration, on 75 hectares’ protection is carried out in areas prone to invasion and species conservation and recreation area with 40 hectares for hiking, ecological tours, bike paths and recreation.

Tree mortality from a short-duration freezing event and global-change-type drought in a Southwestern piñon-juniper woodland, USA

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2014-01-01

This study documents tree mortality in Big Bend National Park in Texas in response to the most acute one-year drought on record, which occurred following a five-day winter freeze. I estimated changes in forest stand structure and species composition due to freezing and drought in the Chisos Mountains of Big Bend National Park using permanent monitoring plot data. The drought killed over half (63%) of the sampled trees over the entire elevation gradient. Significant mortality occurred in trees up to 20 cm diameter (P Pinus cembroides Zucc. experienced the highest seedling and tree mortality (P droughts under climate change will likely cause even greater damage to trees that survived this record drought, especially if such events follow freezes. The results from this study highlight the vulnerability of trees in the Southwest to climatic change and that future shifts in forest structure can have large-scale community consequences. PMID:24949231

Tree mortality from a short-duration freezing event and global-change-type drought in a Southwestern piñon-juniper woodland, USA

OpenAIRE

Helen M. Poulos

2014-01-01

This study documents tree mortality in Big Bend National Park in Texas in response to the most acute one-year drought on record, which occurred following a five-day winter freeze. I estimated changes in forest stand structure and species composition due to freezing and drought in the Chisos Mountains of Big Bend National Park using permanent monitoring plot data. The drought killed over half (63%) of the sampled trees over the entire elevation gradient. Significant mortality occurred in trees...

Tree mortality from a short-duration freezing event and global-change-type drought in a Southwestern piñon-juniper woodland, USA

Directory of Open Access Journals (Sweden)

Helen M. Poulos

2014-06-01

Full Text Available This study documents tree mortality in Big Bend National Park in Texas in response to the most acute one-year drought on record, which occurred following a five-day winter freeze. I estimated changes in forest stand structure and species composition due to freezing and drought in the Chisos Mountains of Big Bend National Park using permanent monitoring plot data. The drought killed over half (63% of the sampled trees over the entire elevation gradient. Significant mortality occurred in trees up to 20 cm diameter (P < 0.05. Pinus cembroides Zucc. experienced the highest seedling and tree mortality (P < 0.0001 (55% of piñon pines died, and over five times as many standing dead pines were observed in 2012 than in 2009. Juniperus deppeana vonSteudal and Quercus emoryi Leibmann also experienced significant declines in tree density (P < 0.02 (30.9% and 20.7%, respectively. Subsequent droughts under climate change will likely cause even greater damage to trees that survived this record drought, especially if such events follow freezes. The results from this study highlight the vulnerability of trees in the Southwest to climatic change and that future shifts in forest structure can have large-scale community consequences.

Tree mortality from a short-duration freezing event and global-change-type drought in a Southwestern piñon-juniper woodland, USA.

Science.gov (United States)

Poulos, Helen M

2014-01-01

This study documents tree mortality in Big Bend National Park in Texas in response to the most acute one-year drought on record, which occurred following a five-day winter freeze. I estimated changes in forest stand structure and species composition due to freezing and drought in the Chisos Mountains of Big Bend National Park using permanent monitoring plot data. The drought killed over half (63%) of the sampled trees over the entire elevation gradient. Significant mortality occurred in trees up to 20 cm diameter (P Quercus emoryi Leibmann also experienced significant declines in tree density (P < 0.02) (30.9% and 20.7%, respectively). Subsequent droughts under climate change will likely cause even greater damage to trees that survived this record drought, especially if such events follow freezes. The results from this study highlight the vulnerability of trees in the Southwest to climatic change and that future shifts in forest structure can have large-scale community consequences.