WorldWideScience

Sample records for terrestrial ecosystem affected

  1. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Bocock, K.L.

    1981-01-01

    This report summarizes information on the distribution and movement of radionuclides in semi-natural terrestrial ecosystems in north-west England with particular emphasis on inputs to, and outputs from ecosystems; on plant and soil aspects; and on radionuclides in fallout and in discharges by the nuclear industry. (author)

  2. Terrestrial ecosystems under warmer and drier climates

    Science.gov (United States)

    Pan, Y.

    2016-12-01

    Future warmer and drier climates will likely affect many of the world's terrestrial ecosystems. These changes will fundamentally reshape terrestrial systems through their components and across organization levels. However, it is unclear to what extent terrestrial ecosystems would be resilient enough to stay put to increased temperature and water stress by only adjusting carbon fluxes and water balances? And to what extent it would reach the thresholds at which terrestrial ecosystems were forced to alter species compositions and ecosystem structures for adapting to newer climates? The energy balance of terrestrial ecosystems link thermal and water conditions to defines terrestrial carbon processes and feedbacks to climate, which will inevitably change under warmer and drier climates. Recent theoretical studies provide a new framework, suggesting that terrestrial ecosystems were capable of balancing costs of carbon gain and water transport to achieve optimums for functioning and distribution. Such a paradigm is critical for understanding the dynamics of future terrestrial ecosystems under climate changes, and facilitate modeling terrestrial ecosystems which needs generalized principles for formulating ecosystem behaviors. This study aims to review some recent studies that explore responses of terrestrial ecosystems to rather novel climate conditions, such as heat-induced droughts, intending to provide better comprehension of complex carbon-water interactions through plants to an ecosystem, and relevant factors that may alleviate or worsen already deteriorated climates such as elevated CO2 and soil conditions.

  3. Terrestrial ecosystems and their change

    Science.gov (United States)

    Anatoly Z. Shvidenko; Eric Gustafson; A. David McGuire; Vjacheslav I. Kharuk; Dmitry G. Schepaschenko; Herman H. Shugart; Nadezhda M. Tchebakova; Natalia N. Vygodskaya; Alexander A. Onuchin; Daniel J. Hayes; Ian McCallum; Shamil Maksyutov; Ludmila V. Mukhortova; Amber J. Soja; Luca Belelli-Marchesini; Julia A. Kurbatova; Alexander V. Oltchev; Elena I. Parfenova; Jacquelyn K. Shuman

    2012-01-01

    This chapter considers the current state of Siberian terrestrial ecosystems, their spatial distribution, and major biometric characteristics. Ongoing climate change and the dramatic increase of accompanying anthropogenic pressure provide different but mostly negative impacts on Siberian ecosystems. Future climates of the region may lead to substantial drying on large...

  4. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Howard, B.J.; Kennedy, V.H.; Nelson, A.

    1983-06-01

    A bibliographical database has been developed to provide quick access to research and background literature in the field of radioecology. This is a development of an earlier database described by Nelson (Bocock 1981). ITE's particular fields of interest have led to a subject bias in the bibliography towards studies in Cumbria, especially those concerned with radionuclides originating from the reprocessing plant at Sellafield, and towards ecological research studies that are complementary to radionuclide studies. Other subjects covered, include the chemistry of radionuclides, budgets and transfers within ecosystems and techniques for the analysis of environmental samples. ITE's research objectives have led to the establishment of a specialized database which is intended to complement rather than compete with the large international databases made available by suppliers such as IRS-DIALTECH or DIALOG. Currently the database holds about 1900 references which are stored on a 2 1/2 megabyte hard disk on a Digital PDP11/34 computer operating under a time shared system. The references follow a standard format. (author)

  5. Linkages between terrestrial ecosystems and the atmosphere

    Science.gov (United States)

    Bretherton, Francis; Dickinson, Robert E.; Fung, Inez; Moore, Berrien, III; Prather, Michael; Running, Steven W.; Tiessen, Holm

    1992-01-01

    The primary research issue in understanding the role of terrestrial ecosystems in global change is analyzing the coupling between processes with vastly differing rates of change, from photosynthesis to community change. Representing this coupling in models is the central challenge to modeling the terrestrial biosphere as part of the earth system. Terrestrial ecosystems participate in climate and in the biogeochemical cycles on several temporal scales. Some of the carbon fixed by photosynthesis is incorporated into plant tissue and is delayed from returning to the atmosphere until it is oxidized by decomposition or fire. This slower (i.e., days to months) carbon loop through the terrestrial component of the carbon cycle, which is matched by cycles of nutrients required by plants and decomposers, affects the increasing trend in atmospheric CO2 concentration and imposes a seasonal cycle on that trend. Moreover, this cycle includes key controls over biogenic trace gas production. The structure of terrestrial ecosystems, which responds on even longer time scales (annual to century), is the integrated response to the biogeochemical and environmental constraints that develop over the intermediate time scale. The loop is closed back to the climate system since it is the structure of ecosystems, including species composition, that sets the terrestrial boundary condition in the climate system through modification of surface roughness, albedo, and, to a great extent, latent heat exchange. These separate temporal scales contain explicit feedback loops which may modify ecosystem dynamics and linkages between ecosystems and the atmosphere. The long-term change in climate, resulting from increased atmospheric concentrations of greenhouse gases (e.g., CO2, CH4, and nitrous oxide (N2O)) will further modify the global environment and potentially induce further ecosystem change. Modeling these interactions requires coupling successional models to biogeochemical models to

  6. Hydrolytic microbial communities in terrestrial ecosystems

    Science.gov (United States)

    Manucharova, Natalia; Chernov, Timofey; Kolcova, Ekaterina; Zelezova, Alena; Lukacheva, Euhenia; Zenova, Galina

    2014-05-01

    Hydrolytic microbial communities in terrestrial ecosystems Manucharova N.A., Chernov T.I., Kolcova E.M., Zelezova A.D., Lukacheva E.G. Lomonosov Moscow State University, Russia Vertical differentiation of terrestrial biogeocenoses is conditioned by the formation of vertical tiers that differ considerably in the composition and structure of microbial communities. All the three tiers, phylloplane, litter and soil, are united by a single flow of organic matter, and are spatially separated successional stages of decomposition of organic substances. Decomposition of organic matter is mainly due to the activity of microorganisms producing enzymes - hydrolase and lyase - which destroy complex organic compounds. Application of molecular biological techniques (FISH) in environmental studies provides a more complete information concerning the taxonomic diversity and potential hydrolytic activity of microbial complexes of terrestrial ecosystems that exist in a wide range of environmental factors (moisture, temperature, redox potential, organic matter). The combination of two molecular biological techniques (FISH and DGGE-analysis of fragments of gene 16S rRNA total amplificate) enables an informative assessment of the differences in the structure of dominant and minor components of hydrolytic complexes formed in different tiers of terrestrial ecosystems. The functional activity of hydrolytic microbial complexes of terrestrial ecosystems is determined by the activity of dominant and minor components, which also have a high gross enzymatic activity. Degradation of biopolymers in the phylloplane is mainly due to the representatives of the Proteobacteria phylogenetic group (classes alpha and beta). In mineral soil horizons, the role of hydrolytic representatives of Firmicutes and Actinobacteria increases. Among the key environmental parameters that determine the functional activity of the hydrolytic (chitinolytic) complex of soil layer (moisture, nutrient supply, successional

  7. Parallel Computing for Terrestrial Ecosystem Carbon Modeling

    International Nuclear Information System (INIS)

    Wang, Dali; Post, Wilfred M.; Ricciuto, Daniel M.; Berry, Michael

    2011-01-01

    Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO 2 . The influence of terrestrial ecosystems on atmospheric CO 2 can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO 2 concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO 2 uptake and respiratory CO 2 release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change

  8. Radionuclide transport processes in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Whicker, F.W.

    1983-01-01

    Some major principles and the status of knowledge concerning the transport of radionuclides through terrestrial ecosystems are reviewed. Fundamental processes which control the flow of radionuclides between ecosystem components such as air, soil, plants, and animals are described, with emphasis on deposition, resuspension, plant uptake, ingestion, and assimilation. Properties of radionuclides, organisms, and ecosystems are examined in relation to their influence on the accumulation of radioactive materials by plants and animals. The effects of the physicochemical nature of the radionuclide; morphology, physiology, and behavior of the organism; and soil, nutrient, and trophic characteristics of the ecosystem are highlighted. Observations in natural ecosystems on radionuclides such as 137 Cs, 90 Sr, 131 I, 3 H, and 239 Pu are used to illustrate current concepts. An assessment of the degree to which the processes controlling radionuclide behavior are understood and of our ability to simulate and predict such behavior with computerized models is offered. Finally, brief comments are made on research needs

  9. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Science.gov (United States)

    Bing Song; Shuli Niu; Ruise Luo; Yiqi Luo; Jiquan Chen; Guirui Yu; Janusz Olejnik; Georg Wohlfahrt; Gerard Kiely; Ako Noormets; Leonardo Montagnani; Alessandro Cescatti; Vincenzo Magliulo; Beverly Elizabeth Law; Magnus Lund; Andrej Varlagin; Antonio Raschi; Matthias Peichl; Mats B. Nilsson; Lutz Merbold

    2014-01-01

    Recent studies revealed convergent temperature sensitivity of ecosystem respiration (Re) within aquatic ecosystems and between terrestrial and aquatic ecosystems. We do not know yet whether various terrestrial ecosystems have consistent or divergent temperature sensitivity. Here, we synthesized 163 eddy covariance flux sites across the world and...

  10. Direct and terrestrial vegetation-mediated effects of environmental change on aquatic ecosystem processes

    Science.gov (United States)

    Becky A. Ball; John S. Kominoski; Heather E. Adams; Stuart E. Jones; Evan S. Kane; Terrance D. Loecke; Wendy M. Mahaney; Jason P. Martina; Chelse M. Prather; Todd M.P. Robinson; Christopher T. Solomon

    2010-01-01

    Global environmental changes have direct effects on aquatic ecosystems, as well as indirect effects through alterations of adjacent terrestrial ecosystem structure and functioning. For example, shifts in terrestrial vegetation communities resulting from global changes can affect the quantity and quality of water, organic matter, and nutrient inputs to aquatic...

  11. Resource subsidies between stream and terrestrial ecosystems under global change

    Science.gov (United States)

    Larsen, Stefano; Muehlbauer, Jeffrey D.; Marti Roca, Maria Eugenia

    2016-01-01

    Streams and adjacent terrestrial ecosystems are characterized by permeable boundaries that are crossed by resource subsidies. Although the importance of these subsidies for riverine ecosystems is increasingly recognized, little is known about how they may be influenced by global environmental change. Drawing from available evidence, in this review we propose a conceptual framework to evaluate the effects of global change on the quality and spatiotemporal dynamics of stream–terrestrial subsidies. We illustrate how changes to hydrological and temperature regimes, atmospheric CO2 concentration, land use and the distribution of nonindigenous species can influence subsidy fluxes by affecting the biology and ecology of donor and recipient systems and the physical characteristics of stream–riparian boundaries. Climate-driven changes in the physiology and phenology of organisms with complex life cycles will influence their development time, body size and emergence patterns, with consequences for adjacent terrestrial consumers. Also, novel species interactions can modify subsidy dynamics via complex bottom-up and top-down effects. Given the seasonality and pulsed nature of subsidies, alterations of the temporal and spatial synchrony of resource availability to consumers across ecosystems are likely to result in ecological mismatches that can scale up from individual responses, to communities, to ecosystems. Similarly, altered hydrology, temperature, CO2 concentration and land use will modify the recruitment and quality of riparian vegetation, the timing of leaf abscission and the establishment of invasive riparian species. Along with morphological changes to stream–terrestrial boundaries, these will alter the use and fluxes of allochthonous subsidies associated with stream ecosystems. Future research should aim to understand how subsidy dynamics will be affected by key drivers of global change, including agricultural intensification, increasing water use and biotic

  12. How lichens impact on terrestrial community and ecosystem properties.

    Science.gov (United States)

    Asplund, Johan; Wardle, David A

    2017-08-01

    Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include

  13. Remote sensing the vulnerability of vegetation in natural terrestrial ecosystems

    Science.gov (United States)

    Alistair M. S. Smith; Crystal A. Kolden; Wade T. Tinkham; Alan F. Talhelm; John D. Marshall; Andrew T. Hudak; Luigi Boschetti; Michael J. Falkowski; Jonathan A. Greenberg; John W. Anderson; Andrew Kliskey; Lilian Alessa; Robert F. Keefe; James R. Gosz

    2014-01-01

    Climate change is altering the species composition, structure, and function of vegetation in natural terrestrial ecosystems. These changes can also impact the essential ecosystem goods and services derived from these ecosystems. Following disturbances, remote-sensing datasets have been used to monitor the disturbance and describe antecedent conditions as a means of...

  14. Radionuclides in an arctic terrestrial ecosystem affected by atmospheric release from the Kraton-3 accidental underground nuclear explosion. 2001-2002

    International Nuclear Information System (INIS)

    Ramzaev, V.; Golikov, V.; Mishine, A.; Kaduka, M.; Burtcev, I.; Gedeonov, A.; Bulatenkov, Y.U.; Strand, P.; Brown, J.

    2004-01-01

    Current distributions of artificial radionuclides (ARN) were studied in the main compartments of a larch-tree forest lethally affected by a radioactive release from the Kraton-3 peaceful underground nuclear explosion (65.9 deg N, 112.3 deg E; Yakutia, Russia; 1978). Samples of soil, fungi, lichens, mosses, grasses, shrubs and trees were obtained at points belonging to four zones categorised by the severity of the ecosystem damage. Sampling was supplemented by dose rate measurements in air and mapping. The area of forest characterised by 100% lethality to adult larches (Larix gmelinii) and with partial, visually-detectable damage of other more radio-resistance species (e.g. lichens, mosses) covers a territory of approximately 1.2 km 2 . Elevated levels of long-lived ARN were found at all sampling sites. Maximum registered levels of the ground contamination with radionuclides of Cs, Sr and Pu were three orders of magnitude higher than those expected from global fallout. The ratios of 137 Cs to some other significant radionuclides in the ground contamination were as follows [mean (range)]: 90 Sr - 0.57(0.02-0.93); 239,240 Pu 44(25-72); 60 Co 470(220-760). Twenty-three years after a discrete contamination event, 90-95% of the total deposited radiocesium and plutonium has still remained in the lichen-moss on-ground cover and in the top 5 cm organic soil layer. At the same time, vertical and horizontal migrations of 90 Sr in soil were more pronounced. Strong surface contamination with 137 Cs, 90 Sr and plutonium was detected at the twigs and bark of the dead larches. The young larches that grew at the contaminated area following the initial destruction of the forest demonstrated a substantial ability to accumulate 137 Cs, 90 Sr and plutonium via roots, while the bushes selectively accumulated mainly radiostrontium. In contrast, some fungi concentrated mostly radiocesium. The levels of gamma dose rate in air and the environmental contamination with 137 Cs were found to

  15. Using Ant Communities For Rapid Assessment Of Terrestrial Ecosystem Health

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L

    2005-06-01

    relative health of the ecosystem. The IBI, though originally for Midwestern streams, has been successfully adapted to other ecoregions and taxa (macroinvertebrates, Lombard and Goldstein, 2004) and has become an important tool for scientists and regulatory agencies alike in determining health of stream ecosystems. The IBI is a specific type of a larger group of methods and procedures referred to as Rapid Bioassessment (RBA). These protocols have the advantage of directly measuring the organisms affected by system perturbations, thus providing an integrated evaluation of system health because the organisms themselves integrate all aspects of their environment and its condition. In addition to the IBI, the RBA concept has also been applied to seep wetlands (Paller et al. 2005) and terrestrial systems (O'Connell et al. 1998, Kremen et al. 1993, Rodriguez et al. 1998, Rosenberg et al. 1986). Terrestrial RBA methods have lagged somewhat behind those for aquatic systems because terrestrial systems are less distinctly defined and seem to have a less universal distribution of an all-inclusive taxon, such as fish in the IBI, upon which to base an RBA. In the last decade, primarily in Australia, extensive development of an RBA using ant communities has shown great promise. Ants have the same advantage for terrestrial RBAs that fish do for aquatic systems in that they are an essential and ubiquitous component of virtually all terrestrial ecosystems. They occupy a broad range of niches, functional groups, and trophic levels and they possess one very important characteristic that makes them ideal for RBA because, similar to the fishes, there is a wide range of tolerance to conditions within the larger taxa. Within ant communities there are certain groups, genera, or species that may be very robust and abundant under even the harshest impacts. There are also taxa that are very sensitive to disturbance and change and their presence or absence is also indicative of the local

  16. Terrestrial ecosystems: an ecological content for radionuclide research

    International Nuclear Information System (INIS)

    Heal, O.W.; Horrill, A.D.

    1983-01-01

    The distribution and retention of radionuclides within terrestrial ecosystems varies greatly with both the radionuclide and the environmental conditions. Physico-chemical conditions, particularly those of the soil, strongly influence element retention but superimposed and interacting with these conditions are the biological processes which control the dynamics of the labile fraction of most elements. Net ecosystem production expresses the complementary biological processes of primary production and decomposition which control the internal element dynamics and the balance of inputs to and outputs from terrestrial ecosystems. Analysis of ecosystem structure and function has shown that although research often concentrates on relatively stable stages of ecosystem development, element retention is high during the early stages of ecosystem succession through the accumulation of plant biomass and dead organic matter. Element output tends to increase with time reaching a balance with inputs in mature ecosystems. Following disturbance, plant uptake tends to be reduced and decomposition stimulated, resulting in increased output until secondary succession and accumulation is re-established. Research on element dynamics in ecosystems indicates that major factors influencing the mobility of radionuclides in terrestrial systems will be the successional state of the ecosystem and intensity of disturbance. (author)

  17. Integrating ecosystem services in terrestrial conservation planning.

    Science.gov (United States)

    Yuan, Mei-Hua; Lo, Shang-Lien; Yang, Chih-Kai

    2017-05-01

    The purpose of this study is to estimate the benefits of ecosystem services for prioritization of land use conservation and to highlight the importance of ecosystem services by comparison between ecosystem service value and green GDP accounting. Based on land use pattern and benefit transfer method, this research estimated value of ecosystem services in Taiwan. Scientific information of land use and land cover change is accessed through multi-year satellite imagery moderate resolution imaging spectroradiometer (MODIS), and geographic information system (GIS) technology. Combined with benefit transfer method, this research estimated the ecosystem service valuation of forest, grassland, cropland, wetland, water, and urban for the period of 2000 to 2015 in Taiwan. It is found that forest made the greatest contribution and the significant increasing area of wetland has huge potential benefit for environmental conservation in Taiwan. We recommend placing maintaining wetland ecosystem in Taiwan with higher priority. This research also compared ecosystem service value with natural capital consumption which would essentially facilitate policy makers to understand the relationship between benefits gained from natural capital and the loss from human-made capital.

  18. Some effects of pollutants in terrestrial ecosystems

    Science.gov (United States)

    Stickel, W.H.; McIntyre, A.D.; Mills, C.F.

    1975-01-01

    occur when persistent chemicals enter organisms that eliminate them poorly. However, loss of chemicals in the food chain must be more common than accumulation. The great concentration from water to aquatic organism is chiefly a physical phenomenon, not a food chain effect, but it affords high starting levels for these chains. Terrestrial food chains often start at a high level with heavily contaminated, struggling prey. Litter feeders are another important base. Vegetation may be contaminated enough to be dangerous to animals that eat it. Dermal and respiratory routes of intoxication occur in the wild, but the oral route is far more important at most times and places. The organisms that govern soil fertility and texture are affected more by cultivation than by pesticides. Above ground, growing knowledge of resistance, species differences, and biological controls is leading to integrated control, in which use of chemicals is limited and specific. We do not know what is happening to most nontarget invertebrates. Amphibians and reptiles may be killed by applications of insecticides, but are not highly sensitive and can carry large residues. Effects of these residues on reproduction are little known. Heavy kills of birds by pesticides still occur in the field. Fish-eating and bird-eating birds also undergo shell thinning and related reproductive troubles in many areas, sometimes to the point of population decline and local or regional extermination. DDE most often correlates with shell thinning in the wild and in experiments. No other known chemical approaches DDE in causing severe and lasting shell thinning. Herbivorous birds seem to be largely immune to this effect. It is uncertain how much dieldrin and PCBs contribute to embryotoxicity in carnivorous birds. Mammals may be killed by the more toxic pesticides, but some of the commonest small rodents are so resistant, and lose their residues so rapidly, that they are of little

  19. Observing terrestrial ecosystems and the carbon cycle from space

    Energy Technology Data Exchange (ETDEWEB)

    Schimel, David [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Pavlick, Ryan [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Fisher, Joshua B. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Asner, Gregory P. [Department of Global Ecology, Carnegie Institution for Science, 260 Panama St. Stanford CA 94305 USA; Saatchi, Sassan [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Townsend, Philip [University of Wisconsin-Madison, Madison WI 53706 USA; Miller, Charles [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Frankenberg, Christian [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Hibbard, Kathy [Pacific Northwest National Laboratory, PO Box 999 MSIN: K9-34 Richland WA 99352 USA; Cox, Peter [College of Engineering, Mathematics and Physical Sciences, University of Exeter, North Park Road Streatham Campus Harrison Building Exeter EX4 4QF UK

    2015-02-06

    Modeled terrestrial ecosystem and carbon cycle feedbacks contribute substantial uncertainty to projections of future climate. The limitations of current observing networks contribute to this uncertainty. Here we present a current climatology of global model predictions and observations for photosynthesis, biomass, plant diversity and plant functional diversity. Carbon cycle tipping points occur in terrestrial regions where fluxes or stocks are largest, and where biological variability is highest, the tropics and Arctic/Boreal zones. Global observations are predominately in the mid-latitudes and are sparse in high and low latitude ecosystems. Observing and forecasting ecosystem change requires sustained observations of sufficient density in time and space in critical regions. Using data and theory available now, we can develop a strategy to detect and forecast terrestrial carbon cycle-climate interactions, by combining in situ and remote techniques.

  20. The Functionally-Assembled Terrestrial Ecosystem Simulator Version 1

    Energy Technology Data Exchange (ETDEWEB)

    2017-06-02

    The Functionally-Assembled Terrestrial Ecosystem Simulator (FATES) is a vegetation model for use in Earth system models (ESMs). The model includes a size- and age-structured representation of tree dynamics, competition between functionally diverse plant functional types, and the biophysics underpinning plant growth, competition, mortality, as well as the carbon, water, and energy exchange with the atmosphere. The FATES model is designed as a modular vegetation model that can be integrated within a host land model for inclusion in ESMs. The model is designed for use in global change studies to understand and project the responses and feedbacks between terrestrial ecosystems and the Earth system under changing climate and other forcings.

  1. Application of a terrestrial ecosystem model to assess ecosystem services in Asia

    Science.gov (United States)

    Shoyama, K.; Yamagata, Y.; Ito, A.; Kohyama, T.

    2011-12-01

    Net primary production (NPP) is a measure of the production rate of organic matter and the gross rate of carbon fixation. NPP is considered as appropriate concept for analyzing variations of the ecosystems induced by land use. Human appropriation of net primary production (HANPP) is a major indicator of human pressures on ecosystems. Land use induced changes in the productivity affect the processes and functions of ecosystems and they are associated with the provision of ecosystem services, such as the provision of biomass through agriculture and forestry, and the regulation services such as the absorption capacity for GHG emissions. A number of studies have been assessed the amount of human induced changes of NPP in the global level and calculated in spatially explicit way. However, the analysis of socio-economic drivers of the changes is still remaining as the main topic in the field. The interrelations between HANPP and social structures and processes are priority of global change research. The methodologies for credible HANPP assessment have been established in the previous studies. The proposed three parameters are (1)NPPptn: NPP of the vegetation that would be assumed to prevail in the absence of human use (potential vegetation), (2)NPPact: NPP of the currently prevailing vegetation (actual vegetation), (3)NPPh: human harvest of NPP (e.g., through agriculture and forestry). We estimated these parameters in Asia using a process-based ecosystem model that describes carbon and nitrogen dynamics of plants and soils for terrestrial ecosystems of the globe. The socio-economic data on crop and timber harvest was applied to estimate the amount of human harvest of NPP. The parameters were calculated for each political unit to discuss social structures responding to various ecosystems. Based on the estimated parameters, we suggest the effective methodology combining spatially explicit gridded data and socio-economic statistical data.

  2. Terrestrial ecosystem responses to global change: A research strategy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Uncertainty about the magnitude of global change effects on terrestrial ecosystems and consequent feedbacks to the atmosphere impedes sound policy planning at regional, national, and global scales. A strategy to reduce these uncertainties must include a substantial increase in funding for large-scale ecosystem experiments and a careful prioritization of research efforts. Prioritization criteria should be based on the magnitude of potential changes in environmental properties of concern to society, including productivity; biodiversity; the storage and cycling of carbon, water, and nutrients; and sensitivity of specific ecosystems to environmental change. A research strategy is proposed that builds on existing knowledge of ecosystem responses to global change by (1) expanding the spatial and temporal scale of experimental ecosystem manipulations to include processes known to occur at large scales and over long time periods; (2) quantifying poorly understood linkages among processes through the use of experiments that manipulate multiple interacting environmental factors over a broader range of relevant conditions than did past experiments; and (3) prioritizing ecosystems for major experimental manipulations on the basis of potential positive and negative impacts on ecosystem properties and processes of intrinsic and/or utilitarian value to humans and on feedbacks of terrestrial ecosystems to the atmosphere.

  3. Global simulation of interactions between groundwater and terrestrial ecosystems

    Science.gov (United States)

    Braakhekke, M. C.; Rebel, K.; Dekker, S. C.; Smith, B.; Van Beek, L. P.; Sutanudjaja, E.; van Kampenhout, L.; Wassen, M. J.

    2016-12-01

    In many places in the world ecosystems are influenced by the presence of a shallow groundwater table. In these regions upward water flux due to capillary rise increases soil moisture availability in the root zone, which has strong positive effect on evapotranspiration. Additionally it has important consequences for vegetation dynamics and fluxes of carbon and nitrogen. Under water limited conditions shallow groundwater stimulates vegetation productivity, and soil organic matter decomposition while under saturated conditions groundwater may have a negative effect on these processes due to lack of oxygen. Furthermore, since plant species differ with respect to their root distribution, preference for moisture conditions, and resistance to oxygen stress, shallow groundwater also influences vegetation type. Finally, processes such as denitrification and methane production occur under strictly anaerobic conditions and are thus strongly influenced by moisture availability. Most global hydrological models and several land surface models simulate groundwater table dynamics and their effects on land surface processes. However, these models typically have relatively simplistic representation of vegetation and do not consider changes in vegetation type and structure and are therefore less suitable to represent effects of groundwater on biogeochemical fluxes. Dynamic global vegetation models (DGVMs), describe land surface from an ecological perspective, combining detailed description of vegetation dynamics and structure and biogeochemical processes. These models are thus more appropriate to simulate the ecological and biogeochemical effects of groundwater interactions. However, currently virtually all DGVMs ignore these effects, assuming that water tables are too deep to affect soil moisture in the root zone. We have implemented a tight coupling between the dynamic global ecosystem model LPJ-GUESS and the global hydrological model PCR-GLOBWB. Using this coupled model we aim to

  4. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems

    Science.gov (United States)

    We tested the hypothesis that diurnal changes in terrestrial CO2 exchange are driven exclusively by the direct effect of the physical environment on plant physiology. We failed to corroborate this assumption, finding instead large diurnal fluctuations in whole ecosystem carbon assimilation across a ...

  5. Microplastics as an emerging threat to terrestrial ecosystems.

    Science.gov (United States)

    de Souza Machado, Anderson Abel; Kloas, Werner; Zarfl, Christiane; Hempel, Stefan; Rillig, Matthias C

    2018-04-01

    Microplastics (plastics microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle-rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant-pollinators. Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems. © 2017 John Wiley & Sons Ltd.

  6. Microplastics in the Terrestrial Ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae).

    Science.gov (United States)

    Huerta Lwanga, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A; Geissen, Violette

    2016-03-01

    Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, digestion of ingested organic matter, microplastic was concentrated in cast, especially at the lowest dose (i.e., 7% in litter) because that dose had the highest proportion of digestible organic matter. Whereas 50 percent of the microplastics had a size of earthworms. These concentration-transport and size-selection mechanisms may have important implications for fate and risk of microplastic in terrestrial ecosystems.

  7. Global variation of carbon use efficiency in terrestrial ecosystems

    Science.gov (United States)

    Tang, Xiaolu; Carvalhais, Nuno; Moura, Catarina; Reichstein, Markus

    2017-04-01

    Carbon use efficiency (CUE), defined as the ratio between net primary production (NPP) and gross primary production (GPP), is an emergent property of vegetation that describes its effectiveness in storing carbon (C) and is of significance for understanding C biosphere-atmosphere exchange dynamics. A constant CUE value of 0.5 has been widely used in terrestrial C-cycle models, such as the Carnegie-Ames-Stanford-Approach model, or the Marine Biological Laboratory/Soil Plant-Atmosphere Canopy Model, for regional or global modeling purposes. However, increasing evidence argues that CUE is not constant, but varies with ecosystem types, site fertility, climate, site management and forest age. Hence, the assumption of a constant CUE of 0.5 can produce great uncertainty in estimating global carbon dynamics between terrestrial ecosystems and the atmosphere. Here, in order to analyze the global variations in CUE and understand how CUE varies with environmental variables, a global database was constructed based on published data for crops, forests, grasslands, wetlands and tundra ecosystems. In addition to CUE data, were also collected: GPP and NPP; site variables (e.g. climate zone, site management and plant function type); climate variables (e.g. temperature and precipitation); additional carbon fluxes (e.g. soil respiration, autotrophic respiration and heterotrophic respiration); and carbon pools (e.g. stem, leaf and root biomass). Different climate metrics were derived to diagnose seasonal temperature (mean annual temperature, MAT, and maximum temperature, Tmax) and water availability proxies (mean annual precipitation, MAP, and Palmer Drought Severity Index), in order to improve the local representation of environmental variables. Additionally were also included vegetation phenology dynamics as observed by different vegetation indices from the MODIS satellite. The mean CUE of all terrestrial ecosystems was 0.45, 10% lower than the previous assumed constant CUE of 0

  8. The potential for regime shifts in high latitude terrestrial ecosystems

    Science.gov (United States)

    Beck, P. S.; Goetz, S. J.

    2011-12-01

    Climate constrains the extent of the two major terrestrial biomes at high latitudes: boreal forests and arctic tundra. Model simulations provide considerable evidence that physical and biogeochemical feedbacks from these regions to the climate system act to maintain a status quo of climate and biome distribution. Ongoing anthropogenically driven changes in climate are particularly pronounced in high latitude regions, and empirical evidence for their influence on tundra and boreal ecosystems is mounting. Global vegetation models project changes to accelerate in coming decades, culminating in profound shifts in high latitude biomes by the end of this century. Regime shifts are surprisingly large changes in a system that occur when a it moves between alternative stable states ('attractors'), without the equivalent large shift of an external driver. In association with climate change, regime shifts in ecosystems could theoretically generate significant modifications to ecosystem-climate feedbacks, in the Arctic for example through the respiration or combustion of large amounts of soil carbon. Here we review evidence for historical regime shifts in terrestrial ecosystems at high latitudes, including shifts in species dominance and distribution. We describe ongoing changes in characteristics of these ecosystems, including vegetation productivity, composition, and the fire regime, and discuss whether they can be indicators of impeding regime shifts. Finally, we discuss the potential of exploiting regime shifts in tundra and boreal systems for climate change mitigation or resource management by forcing ecosystems to shift towards a more desirable stable state.

  9. The carbon balance of terrestrial ecosystems of China

    Directory of Open Access Journals (Sweden)

    Pilli R

    2009-05-01

    Full Text Available A comment is made on a recent letter published on Nature, in which different methodologies are applied to estimate the carbon balance of terrestrial ecosystems of China. A global carbon sink of 0.19-0.26 Pg per year is estimated during the 1980s and 1990s, and it is estimated that in 2006 terrestrial ecosystems have absorbed 28-37 per cent of global carbon emissions in China. Most of the carbon absorption is attributed to large-scale plantation made since the 1980s and shrub recovery. These results will certainly be valuable in the frame of the so-called “REDD” (Reducing Emissions from Deforestation forest Degradation in developing countries mechanism (UN convention on climate change UNFCCC.

  10. Benchmarking Terrestrial Ecosystem Models in the South Central US

    Science.gov (United States)

    Kc, M.; Winton, K.; Langston, M. A.; Luo, Y.

    2016-12-01

    Ecosystem services and products are the foundation of sustainability for regional and global economy since we are directly or indirectly dependent on the ecosystem services like food, livestock, water, air, wildlife etc. It has been increasingly recognized that for sustainability concerns, the conservation problems need to be addressed in the context of entire ecosystems. This approach is even more vital in the 21st century with formidable increasing human population and rapid changes in global environment. This study was conducted to find the state of the science of ecosystem models in the South-Central region of US. The ecosystem models were benchmarked using ILAMB diagnostic package developed as a result of International Land Model Benchmarking (ILAMB) project on four main categories; viz, Ecosystem and Carbon Cycle, Hydrology Cycle, Radiation and Energy Cycle and Climate forcings. A cumulative assessment was generated with weighted seven different skill assessment metrics for the ecosystem models. This synthesis on the current state of the science of ecosystem modeling in the South-Central region of US will be highly useful towards coupling these models with climate, agronomic, hydrologic, economic or management models to better represent ecosystem dynamics as affected by climate change and human activities; and hence gain more reliable predictions of future ecosystem functions and service in the region. Better understandings of such processes will increase our ability to predict the ecosystem responses and feedbacks to environmental and human induced change in the region so that decision makers can make an informed management decisions of the ecosystem.

  11. Effects of carbon turnover time on terrestrial ecosystem carbon storage

    Science.gov (United States)

    Yan, Yaner; Zhou, Xuhui; Jiang, Lifeng; Luo, Yiqi

    2017-12-01

    Carbon (C) turnover time is a key factor in determining C storage capacity in various plant and soil pools as well as terrestrial C sink in a changing climate. However, the effects of C turnover time on ecosystem C storage have not been well explored. In this study, we compared mean C turnover times (MTTs) of ecosystem and soil, examined their variability to climate, and then quantified the spatial variation in ecosystem C storage over time from changes in C turnover time and/or net primary production (NPP). Our results showed that mean ecosystem MTT based on gross primary production (GPP; MTTEC_GPP = Cpool/GPP, 25.0 ± 2.7 years) was shorter than soil MTT (MTTsoil = Csoil/NPP, 35.5 ± 1.2 years) and NPP-based ecosystem MTT (MTTEC_NPP = Cpool/NPP, 50.8 ± 3 years; Cpool and Csoil referred to ecosystem or soil C storage, respectively). On the biome scale, temperature is the best predictor for MTTEC (R2 = 0.77, p impact on ecosystem C storage, which deserves further study in the future.

  12. Spatial covariation between freshwater and terrestrial ecosystem services.

    Science.gov (United States)

    Holland, Robert A; Eigenbrod, Felix; Armsworth, Paul R; Anderson, Barbara J; Thomas, Chris D; Heinemeyer, Andreas; Gillings, Simon; Roy, David B; Gaston, Kevin J

    2011-09-01

    To inform the design and implementation of land-use policies that consider the variety of goods and services people derive from ecosystems, it is essential to understand spatial patterns of individual services, how multiple services relate to each other, and how these relationships vary across spatial scales and localities. Despite the importance of freshwater as a determinant of regional economic and human demographic patterns, there are surprisingly few studies that map the provision of a range of services associated with the quality of the aquatic environment. Here we examine relationships between indicators of riverine water and associated habitat quality, freshwater biodiversity, three terrestrial ecosystem services, and terrestrial biodiversity across England and Wales. The results indicate strong associations between our indicators of freshwater services. However, a comparison of these indicators of freshwater services with other ecosystem services (carbon storage, agricultural production, recreation) and biodiversity of species of conservation concern in the surrounding terrestrial landscape shows no clear relationships. While there are potential policy "win-wins" for the protection of multiple services shown by associations between indicators of freshwater services and carbon storage in upland areas of Britain, the other ecosystem services showed either negative or no relationships with the indicators of freshwater services. We also consider the influence that spatial scale has on these relationships using River Basin Districts. Our results indicate that relationships between indicators of services can change dramatically depending on the societal pressures and other regional conditions. Thus, the delivery of multiple ecosystem services requires the development of regional strategies, or of national strategies that take account of regional variation.

  13. Terrestrial Ecosystem Responses to Global Change: A Research Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Ecosystems Working Group,

    1998-09-23

    Uncertainty about the magnitude of global change effects on terrestrial ecosystems and consequent feedbacks to the atmosphere impedes sound policy planning at regional, national, and global scales. A strategy to reduce these uncertainties must include a substantial increase in funding for large-scale ecosystem experiments and a careful prioritization of research efforts. Prioritization criteria should be based on the magnitude of potential changes in environmental properties of concern to society, including productivity; biodiversity; the storage and cycling of carbon, water, and nutrients; and sensitivity of specific ecosystems to environmental change. A research strategy is proposed that builds on existing knowledge of ecosystem responses to global change by (1) expanding the spatial and temporal scale of experimental ecosystem manipulations to include processes known to occur at large scales and over long time periods; (2) quantifying poorly understood linkages among processes through the use of experiments that manipulate multiple interacting environmental factors over a broader range of relevant conditions than did past experiments; and (3) prioritizing ecosystems for major experimental manipulations on the basis of potential positive and negative impacts on ecosystem properties and processes of intrinsic and/or utilitarian value to humans and on feedbacks of terrestrial ecosystems to the atmosphere. Models and experiments are equally important for developing process-level understanding into a predictive capability. To support both the development and testing of mechanistic ecosystem models, a two-tiered design of ecosystem experiments should be used. This design should include both (1) large-scale manipulative experiments for comprehensive testing of integrated ecosystem models and (2) multifactor, multilevel experiments for parameterization of process models across the critical range of interacting environmental factors (CO{sub 2}, temperature, water

  14. Impacts of droughts on carbon sequestration by China's terrestrial ecosystems from 2000 to 2011

    Science.gov (United States)

    Liu, Y.; Zhou, Y.; Ju, W.; Wang, S.; Wu, X.; He, M.; Zhu, G.

    2014-05-01

    In recent years, China's terrestrial ecosystems have experienced frequent droughts. How these droughts have affected carbon sequestration by the terrestrial ecosystems is still unclear. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model, driven by remotely sensed vegetation parameters, was employed to assess the effects of droughts on net ecosystem productivity (NEP) of terrestrial ecosystems in China from 2000 to 2011. Droughts of differing severity, as indicated by a standard precipitation index (SPI), hit terrestrial ecosystems in China extensively in 2001, 2006, 2009, and 2011. The national total annual NEP exhibited the slight decline of -11.3 Tg C yr-2 during the aforementioned years of extensive droughts. The NEP reduction ranged from 61.1 Tg C yr-1 to 168.8 Tg C yr-1. National and regional total NEP anomalies were correlated with the annual mean SPI, especially in Northwest China, North China, Central China, and Southwest China. The reductions in annual NEP in 2001 and 2011 might have been caused by a larger decrease in annual gross primary productivity (GPP) than in annual ecosystem respiration (ER). The reductions experienced in 2009 might be due to a decrease in annual GPP and an increase in annual ER, while reductions in 2006 could stem from a larger increase in ER than in GPP. The effects of droughts on NEP lagged up to 3-6 months, due to different responses of GPP and ER. In eastern China, where is humid and warm, droughts have predominant and short-term lagged influences on NEP. In western regions, cold and arid, the drought effects on NEP were relatively weaker but prone to lasting longer.

  15. Ash in fire affected ecosystems

    Science.gov (United States)

    Pereira, Paulo; Jordan, Antonio; Cerda, Artemi; Martin, Deborah

    2015-04-01

    Ash in fire affected ecosystems Ash lefts an important footprint in the ecosystems and has a key role in the immediate period after the fire (Bodi et al., 2014; Pereira et al., 2015). It is an important source of nutrients for plant recover (Pereira et al., 2014a), protects soil from erosion and controls soil hydrological process as runoff, infiltration and water repellency (Cerda and Doerr, 2008; Bodi et al., 2012, Pereira et al., 2014b). Despite the recognition of ash impact and contribution to ecosystems recuperation, it is assumed that we still have little knowledge about the implications of ash in fire affected areas. Regarding this situation we wanted to improve our knowledge in this field and understand the state of the research about fire ash around world. The special issue about "The role of ash in fire affected ecosystems" currently in publication in CATENA born from the necessity of joint efforts, identify research gaps, and discuss future cooperation in this interdisciplinary field. This is the first special issue about fire ash in the international literature. In total it will be published 10 papers focused in different aspects of the impacts of ash in fire affected ecosystems from several parts of the world: • Fire reconstruction using charcoal particles (Burjachs and Espositio, in press) • Ash slurries impact on rheological properties of Runoff (Burns and Gabet, in press) • Methods to analyse ash conductivity and sorbtivity in the laboratory and in the field (Balfour et al., in press) • Termogravimetric and hydrological properties of ash (Dlapa et al. in press) • Effects of ash cover in water infiltration (Leon et al., in press) • Impact of ash in volcanic soils (Dorta Almenar et al., in press; Escuday et al., in press) • Ash PAH and Chemical extracts (Silva et al., in press) • Microbiology (Barreiro et al., in press; Lombao et al., in press) We believe that this special issue will contribute importantly to the better understanding of

  16. Climate legacies drive global soil carbon stocks in terrestrial ecosystems.

    Science.gov (United States)

    Delgado-Baquerizo, Manuel; Eldridge, David J; Maestre, Fernando T; Karunaratne, Senani B; Trivedi, Pankaj; Reich, Peter B; Singh, Brajesh K

    2017-04-01

    Climatic conditions shift gradually over millennia, altering the rates at which carbon (C) is fixed from the atmosphere and stored in the soil. However, legacy impacts of past climates on current soil C stocks are poorly understood. We used data from more than 5000 terrestrial sites from three global and regional data sets to identify the relative importance of current and past (Last Glacial Maximum and mid-Holocene) climatic conditions in regulating soil C stocks in natural and agricultural areas. Paleoclimate always explained a greater amount of the variance in soil C stocks than current climate at regional and global scales. Our results indicate that climatic legacies help determine global soil C stocks in terrestrial ecosystems where agriculture is highly dependent on current climatic conditions. Our findings emphasize the importance of considering how climate legacies influence soil C content, allowing us to improve quantitative predictions of global C stocks under different climatic scenarios.

  17. Contrasting responses of water use efficiency to drought across global terrestrial ecosystems

    OpenAIRE

    Yang, Yuting; Guan, Huade; Batelaan, Okke; McVicar, Tim R.; Long, Di; Piao, Shilong; Liang, Wei; Liu, Bing; Jin, Zhao; Simmons, Craig T.

    2016-01-01

    Drought is an intermittent disturbance of the water cycle that profoundly affects the terrestrial carbon cycle. However, the response of the coupled water and carbon cycles to drought and the underlying mechanisms remain unclear. Here we provide the first global synthesis of the drought effect on ecosystem water use efficiency (WUE?=?gross primary production (GPP)/evapotranspiration (ET)). Using two observational WUE datasets (i.e., eddy-covariance measurements at 95 sites (526 site-years) an...

  18. Factors influencing DOC leaching from terrestrial ecosystems: a database analysis

    Science.gov (United States)

    Camino Serrano, M.; Janssens, I.; Luyssaert, S.; Ciais, P.; Gielen, B.

    2012-04-01

    The lateral transport of dissolved organic carbon (DOC) is an important process linking terrestrial and aquatic ecosystems. Neglecting these fluxes can lead to biased of eddy covariance-based estimates of terrestrial ecosystem carbon sequestration. The necessity for integrating DOC leaching in carbon cycle models is thus clear, especially in view of future model development aiming at directly linking terrestrial, freshwater and ocean carbon cycles. However, to achieve this goal, more accurate information is needed in order to better understand and predict dissolved organic carbon dynamics. DOC concentrations mainly vary by geographical location, soil and vegetation types, topography, season and climate. Within this framework, we developed a database on DOC concentrations and fluxes with the aim of better understanding how those parameters determine DOC variations. This database compiles DOC concentrations and fluxes in soil solution and creeks at site or catchment level for different ecosystems around the world, but with special focus on the Northern Hemisphere and on peatland ecosystems. The database currently includes information from around 120 sites, gathered from published literature and datasets accessible on the internet. The database contains annual, seasonal and monthly data on DOC, dissolved inorganic carbon (DIC), dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN) and also includes other meta-data related to the site, such as land cover, soil properties, climate, annual water balance and other soil solution parameters. This compiled dataset allows to study the influence of several physical factors that determine DOC production in soils. We will present the observed relationships between drivers, such as precipitation, drainage flows, soil pH, soil texture, and DOC concentration/ DOC fluxes at different levels, ecosystem types, temporal scales (monthly versus annual or seasonal), and soil depths. The same relations will be analysed

  19. Impacts of Climate Chnage on Terrestrial Ecosystems Functioning - An Overview

    OpenAIRE

    Beier, Claus; Ambus, Per; Amdal, M. F.; Christensen, Steen; Holmstrup, M.; Larsen, Klaus Steenberg; Michelsen, A.; Mikkelsen, Teis Nørgaard; Priemé, A.; Schmidt, I. K.; Pilegaard, Kim

    2015-01-01

    CLiMA!TE - backgroundThe concentration of CO2 in the atmosphere is increasing, globaltemperatures are increasing, and local precipitation patterns arechanging with increases in the intensity of rain events and droughtperiods. This is expected to affect the structure and functioning ofterrestrial ecosystems (IPCC, 2013) with major impacts on naturalenvironments as well as ecosystems used for agriculture or forestry. Over the past three decades, major efforts have been devoted to understandand ...

  20. The roles of productivity and ecosystem size in determining food chain length in tropical terrestrial ecosystems.

    Science.gov (United States)

    Young, Hillary S; McCauley, Douglas J; Dunbar, Robert B; Hutson, Michael S; Ter-Kuile, Ana Miller; Dirzo, Rodolfo

    2013-03-01

    Many different drivers, including productivity, ecosystem size, and disturbance, have been considered to explain natural variation in the length of food chains. Much remains unknown about the role of these various drivers in determining food chain length, and particularly about the mechanisms by which they may operate in terrestrial ecosystems, which have quite different ecological constraints than aquatic environments, where most food chain length studies have been thus far conducted. In this study, we tested the relative importance of ecosystem size and productivity in influencing food chain length in a terrestrial setting. We determined that (1) there is no effect of ecosystem size or productive space on food chain length; (2) rather, food chain length increases strongly and linearly with productivity; and (3) the observed changes in food chain length are likely achieved through a combination of changes in predator size, predator behavior, and consumer diversity along gradients in productivity. These results lend new insight into the mechanisms by which productivity can drive changes in food chain length, point to potential for systematic differences in the drivers of food web structure between terrestrial and aquatic systems, and challenge us to consider how ecological context may control the drivers that shape food chain length.

  1. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    Science.gov (United States)

    Chen, Min

    period of 2003-2010. Ecosystem heterotrophic respiration (RH) was negatively affected by the aerosol loading. These results support previous conclusions of the advantage of aerosol light scattering effect on plant productions in other studies but suggest there is strong spatial variation. This study finds indirect aerosol effects on terrestrial ecosystem carbon dynamics through affecting plant phenology, thermal and hydrological environments. All these evidences suggested that the aerosol direct radiative effect on global terrestrial ecosystem carbon dynamics should be considered to better understand the global carbon cycle and climate change. An ozone sub-model is developed in this dissertation and fully coupled with iTem. The coupled model, named iTemO3 considers the processes of ozone stomatal deposition, plant defense to ozone influx, ozone damage and plant repairing mechanism. By using a global atmospheric chemical transport model (GACTM) estimated ground-level ozone concentration data, the model estimated global annual stomatal ozone deposition is 234.0 Tg O3 yr-1 and indicates which regions have high ozone damage risk. Different plant functional types, sunlit and shaded leaves are shown to have different responses to ozone. The model predictions suggest that ozone has caused considerable change on global terrestrial ecosystem carbon storage and carbon exchanges over the study period 2004-2008. The study suggests that uncertainty of the key parameters in iTemO3 could result in large errors in model predictions. Thus more experimental data for better model parameterization is highly needed.

  2. Biomass Resources Distribution in the Terrestrial Ecosystem of China

    Directory of Open Access Journals (Sweden)

    Na Li

    2015-07-01

    Full Text Available In this study, Moderate Resolution Imaging Spectroradiometer (MODIS data and the multiple linear regression model were used to estimate distribution of biomass resources in 2010. The establishment of models, developed using different vegetation biomass sample data, normalized difference vegetation index (NDVI, leaf area index (LAI, meteorological data, coordinates, terrain data, and statistical data. Results based on a cross-validation approach show that the model can explain 95.6% of the variance in biomass, with a relative estimation error of 67 g·m−2 for a range of biomass between 0–73,875 g·m−2. Spatial statistic results were consistent with the practical condition in most cases. The above- and below-ground biomass (ABGB of China was estimated to be 31.1 Pg (1 Pg = 1015 g in 2010. The forest ecosystem has the largest total biomass, which represents about 70% of the whole terrestrial ecosystem. The desert ecosystem has minimum biomass value. The Belowground Endowment (BRE varied differently in spatial distribution, with the high values occurring in the southeast and northeast. The low values were primarily distributed in north and northwest regions, where it is mostly desert and few plants. Biomass per capita indicates the availability of natural resources per capita. Tibet had the maximum biomass per capita (807 tone in 2010. Shanghai and Tianjin had the minimum biomass per capita, less than 500 kg. Shanghai, Tianjin, Guangzhou, Beijing, and Hainan had negative growth of biomass per capita.

  3. Terrestrial ecosystem nowcasts and forecasts for North America

    Science.gov (United States)

    Nemani, R. R.; Votava, P.; Michaelis, A.; Ichii, K.; Hashimoto, H.; Milesi, C.; Dungan, J.; White, M.

    2006-12-01

    Understanding and predicting changes in carbon cycling of landscapes and adjacent oceans are important goals for the North American Carbon Program (NACP). Achieving these goals requires integration of a number of data sources that are both point-based and spatially explicit, as in the case of satellite data, and models to produce ecosystem fluxes at a variety of spatio-temporal scales. Here we show an adaptation of our data and modeling system, the Terrestrial Observation and Prediction System (TOPS) over North America to operationally produce nowcasts (daily) and forecasts (up to 7 days) of ecosystem fluxes including gross and net primary production and net ecosystem exchange. TOPS is a software system designed to seamlessly integrate data from satellite, aircraft, and ground sensors, and weather/climate models with application models to quickly and reliably produce operational nowcasts and forecasts of ecological conditions. The underlying technologies in TOPS are: 1) Ecosystem models of a variety of flavors ranging from process-based models that use satellite-derived inputs along with surface climate data, weather/climate forecasts to empirical models that rely on historical relationships between climate and ecological phenomenon such as fire risk, disease/pest outbreaks, etc.; 2) Planning and scheduling that facilitate a goal-based data collection and pre-processing so that all the necessary information is available in the required format for a given model run; and 3) Causality analysis and model generation using advances in data mining and machine learning. Nowcasts and forecasts are continuously evaluated using observations from diverse networks: SNOTEL for snow cover, USGS/Streamflow for runoff, USDA/SCAN for soil moisture, GLOBE for phenology and FLUXNET for carbon/water fluxes. Model parameters are optimized based on the spatio-temporal biases identified during model evaluation

  4. The terrestrial ecosystem program for the Yucca Mountain Project

    International Nuclear Information System (INIS)

    Ostler, W.K.; O'Farrell, T.P.

    1994-01-01

    DOE has implemented a program to monitor and mitigate impacts associated with site Characterization Activities at Yucca Mountain on the environment. This program has a sound experimental and statistical base. Monitoring data has been collected for parts of the program since 1989. There have been numerous changes in the Terrestrial Ecosystems Program since 1989 that reflect changes in the design and locations of Site Characterization Activities. There have also been changes made in the mitigation techniques implemented to protect important environmental resources based on results from the research efforts at Yucca Mountain. These changes have strengthened DOE efforts to ensure protection of the environmental during Site Characterization. DOE,has developed and implemented an integrated environmental program that protects the biotic environment and will restore environmental quality at Yucca Mountain

  5. Function of Wildfire-Deposited Pyrogenic Carbon in Terrestrial Ecosystems

    Directory of Open Access Journals (Sweden)

    Melissa R. A. Pingree

    2017-08-01

    Full Text Available Fire is an important driver of change in most forest, savannah, and prairie ecosystems and fire-altered organic matter, or pyrogenic carbon (PyC, conveys numerous functions in soils of fire-maintained terrestrial ecosystems. Although an exceptional number of recent review articles and books have addressed agricultural soil application of charcoal or biochar, few reviews have addressed the functional role of naturally formed PyC in fire-maintained ecosystems. Recent advances in molecular spectroscopic techniques have helped strengthen our understanding of PyC as a ubiquitous, complex material that is capable of altering soil chemical, physical, and biological properties and processes. The uniquely recalcitrant nature of PyC in soils is partly a result of its stable C = C double-bonded, graphene-like structure and C-rich, N-poor composition. This attribute allows it to persist in soils for hundreds to thousands of years and represent net ecosystem C sequestration in fire-maintained ecosystems. The rapid formation of PyC during wildfire or anthropogenic fire events short-circuits the normally tortuous pathway of recalcitrant soil C formation. Existing literature also suggests that PyC provides an essential role in the cycling of certain nutrients, greatly extending the timeframe by which fires influence soil processes and facilitating recovery in ecosystems where organic matter inputs are low and post-fire surface soil bacterial and fungal activity is reduced. The high surface area of PyC allows for the adsorption a broad spectrum of organic compounds that directly or indirectly influence microbial processes after fire events. Adsorption capacity and microsite conditions created by PyC yields a “charosphere” effect in soil with heightened microbial activity in the vicinity of PyC. In this mini-review, we explore the function of PyC in natural and semi-natural settings, provide a mechanistic approach to understanding these functions, and examine

  6. USING ANT COMMUNITIES FOR RAPID ASSESSMENT OF TERRESTRIAL ECOSYSTEM HEALTH

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L; Doug Martin, D; Michael Paller, M; Eric Nelson, E

    2007-01-12

    Ecosystem health with its near infinite number of variables is difficult to measure, and there are many opinions as to which variables are most important, most easily measured, and most robust, Bioassessment avoids the controversy of choosing which physical and chemical parameters to measure because it uses responses of a community of organisms that integrate all aspects of the system in question. A variety of bioassessment methods have been successfully applied to aquatic ecosystems using fish and macroinvertebrate communities. Terrestrial biotic index methods are less developed than those for aquatic systems and we are seeking to address this problem here. This study had as its objective to examine the baseline differences in ant communities at different seral stages from clear cut back to mature pine plantation as a precursor to developing a bioassessment protocol. Comparative sampling was conducted at four seral stages; clearcut, 5 year, 15 year and mature pine plantation stands. Soil and vegetation data were collected at each site. All ants collected were preserved in 70% ethyl alcohol and identified to genus. Analysis of the ant data indicates that ants respond strongly to the habitat changes that accompany ecological succession in managed pine forests and that individual genera as well as ant community structure can be used as an indicator of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in the mature seral stages was likely related to conditions on the forest floor which favored litter dwelling and cool climate specialists.

  7. Adaptation policies to increase terrestrial ecosystem resilience. Potential utility of a multicriteria approach

    Energy Technology Data Exchange (ETDEWEB)

    de Bremond, Ariane [Univ. of Maryland, College Park, MD (United States); Joint Global Change Research Inst., College Park, MD (United States); Engle, Nathan L. [World Bank, Washington, DC (United States)

    2014-01-30

    Climate change is rapidly undermining terrestrial ecosystem resilience and capacity to continue providing their services to the benefit of humanity and nature. Because of the importance of terrestrial ecosystems to human well-being and supporting services, decision makers throughout the world are busy creating policy responses that secure multiple development and conservation objectives- including that of supporting terrestrial ecosystem resilience in the context of climate change. This article aims to advance analyses on climate policy evaluation and planning in the area of terrestrial ecosystem resilience by discussing adaptation policy options within the ecology-economy-social nexus. The paper evaluates these decisions in the realm of terrestrial ecosystem resilience and evaluates the utility of a set of criteria, indicators, and assessment methods, proposed by a new conceptual multi-criteria framework for pro-development climate policy and planning developed by the United Nations Environment Programme. Potential applications of a multicriteria approach to climate policy vis-A -vis terrestrial ecosystems are then explored through two hypothetical case study examples. The paper closes with a brief discussion of the utility of the multi-criteria approach in the context of other climate policy evaluation approaches, considers lessons learned as a result efforts to evaluate climate policy in the realm of terrestrial ecosystems, and reiterates the role of ecosystem resilience in creating sound policies and actions that support the integration of climate change and development goals.

  8. Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

    Science.gov (United States)

    More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change as well as carbon accounting and climate policy-making depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems...

  9. Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

    Science.gov (United States)

    Jingfeng Xiaoa; Qianlai Zhuang; Beverly E. Law; Dennis D. Baldocchi; Jiquan Chen; al. et.

    2011-01-01

    More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a...

  10. Application of a terrestrial ecosystem model (ORCHIDEE-STICS) in simulating energy and CO2 fluxes in Asian rice croplands

    Science.gov (United States)

    Wang, X.; Piao, S.; Ciais, P.; Vuichard, N.

    2012-12-01

    Process-based terrestrial ecosystem models have shown great potentials in predicting the response of managed ecosystems to environmental changes. However, the simulated water and carbon fluxes over rice ecosystems in tropical Asia are still subject to large uncertainties, partly due to poorly constrained parameters in the models. Here, a terrestrial ecosystem model incorporating a more realistic crop module (ORCHIDEE-STICS) was calibrated against in-situ flux data and observed and remotely sensed leaf area indexes over rice ecosystems in Asia. The key parameters adjusted include maximum photosynthetic carboxylation rate (Vcmax) and electron transport rate (Vjmax), temperature sensitivity of heterotrophic respiration (Q10) and a series of critical thresholds for different crop development stages. Compared with the observations, the calibrated model more realistically simulated the seasonal and year-to-year variation of the observed water and carbon fluxes with reductions in the root mean square difference and better timing in the crop development stages. Sensitivity tests further reveal that management practices like the timing of transplanting and draining could affect the seasonal and inter-annual variation of the net carbon exchange, suggesting that the absence of explicit accounting the change of management practices in the terrestrial ecosystem models may induce large uncertainties in predicting cropland ecosystem response to future climate change.

  11. Evolutionary diversification in stickleback affects ecosystem functioning.

    Science.gov (United States)

    Harmon, Luke J; Matthews, Blake; Des Roches, Simone; Chase, Jonathan M; Shurin, Jonathan B; Schluter, Dolph

    2009-04-30

    Explaining the ecological causes of evolutionary diversification is a major focus of biology, but surprisingly little has been said about the effects of evolutionary diversification on ecosystems. The number of species in an ecosystem and their traits are key predictors of many ecosystem-level processes, such as rates of productivity, biomass sequestration and decomposition. Here we demonstrate short-term ecosystem-level effects of adaptive radiation in the threespine stickleback (Gasterosteus aculeatus) over the past 10,000 years. These fish have undergone recent parallel diversification in several lakes in coastal British Columbia, resulting in the formation of two specialized species (benthic and limnetic) from a generalist ancestor. Using a mesocosm experiment, we demonstrate that this diversification has strong effects on ecosystems, affecting prey community structure, total primary production, and the nature of dissolved organic materials that regulate the spectral properties of light transmission in the system. However, these ecosystem effects do not simply increase in their relative strength with increasing specialization and species richness; instead, they reflect the complex and indirect consequences of ecosystem engineering by sticklebacks. It is well known that ecological factors influence adaptive radiation. We demonstrate that adaptive radiation, even over short timescales, can have profound effects on ecosystems.

  12. Isotopic identification of nitrogen hotspots across natural terrestrial ecosystems

    Directory of Open Access Journals (Sweden)

    E. Bai

    2012-08-01

    Full Text Available Nitrogen (N influences local biological processes, ecosystem productivity, the composition of the atmospheric-climate system, and the human endeavour as a whole. Here we use natural variations in N isotopes, coupled with two models, to trace global pathways of N loss from the land to the water and atmosphere. We show that denitrification accounts for approximately 35 % of total N losses from the natural soil, with NO, N2O, and N2 fluxes equal to 15.7 ± 4.7 Tg N yr−1, 10.2 ± 3.0 Tg N yr−1, and 21.0 ± 6.1 Tg N yr−1, respectively. Our analysis points to tropical regions as the major "hotspot" of nitrogen export from the terrestrial biosphere, accounting for 71 % of global N losses from the natural land surface. The poorly studied Congo Basin is further identified as one of the major natural sources of atmospheric N2O. Extra-tropical areas, by contrast, lose a greater fraction of N via leaching pathways (~77 % of total N losses than do tropical biomes, likely contributing to N limitations of CO2 uptake at higher latitudes. Our results provide an independent constraint on global models of the N cycle among different regions of the unfertilized biosphere.

  13. Nitrogen-induced terrestrial eutrophication: cascading effects and impacts on ecosystem services

    Science.gov (United States)

    Christopher M. Clark; Michael D. Bell; James W. Boyd; Jana E. Compton; Eric A. Davidson; Christine Davis; Mark E. Fenn; Linda Geiser; Laurence Jones; Tamara F. Blett

    2017-01-01

    Human activity has significantly increased the deposition of nitrogen (N) on terrestrial ecosystems over pre-industrial levels leading to a multitude of effects including losses of biodiversity, changes in ecosystem functioning, and impacts on human well-being. It is challenging to explicitly link the level of deposition on an ecosystem to the cascade of...

  14. Microbial characterization of toluene-degrading denitrifying consortia obtained from terrestrial and marine ecosystems.

    Science.gov (United States)

    An, Y-J; Joo, Y-H; Hong, I-Y; Ryu, H-W; Cho, K-S

    2004-10-01

    The degradation characteristics of toluene coupled to nitrate reduction were investigated in enrichment culture and the microbial communities of toluene-degrading denitrifying consortia were characterized by denaturing gradient gel electrophoresis (DGGE) technique. Anaerobic nitrate-reducing bacteria were enriched from oil-contaminated soil samples collected from terrestrial (rice field) and marine (tidal flat) ecosystems. Enriched consortia degraded toluene in the presence of nitrate as a terminal electron acceptor. The degradation rate of toluene was affected by the initial substrate concentration and co-existence of other hydrocarbons. The types of toluene-degrading denitrifying consortia depended on the type of ecosystem. The clone RS-7 obtained from the enriched consortium of the rice field was most closely related to a toluene-degrading and denitrifying bacterium, Azoarcus denitrificians (A. tolulyticus sp. nov.). The clone TS-11 detected in the tidal flat enriched consortium was affiliated to Thauera sp. strain S2 (T. aminoaromatica sp. nov.) that was able to degrade toluene under denitrifying conditions. This indicates that environmental factors greatly influence microbial communities obtained from terrestrial (rice field) and marine (tidal flat) ecosystems.

  15. How do persistent organic pollutants be coupled with biogeochemical cycles of carbon and nutrients in terrestrial ecosystems under global climate change?

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Ying [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation; Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Xu, Zhihong; Reverchon, Frederique [Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Luo, Yongming [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation

    2012-03-15

    Global climate change (GCC), especially global warming, has affected the material cycling (e.g., carbon, nutrients, and organic chemicals) and the energy flows of terrestrial ecosystems. Persistent organic pollutants (POPs) were regarded as anthropogenic organic carbon (OC) source, and be coupled with the natural carbon (C) and nutrient biogeochemical cycling in ecosystems. The objective of this work was to review the current literature and explore potential coupling processes and mechanisms between POPs and biogeochemical cycles of C and nutrients in terrestrial ecosystems induced by global warming. Global warming has caused many physical, chemical, and biological changes in terrestrial ecosystems. POPs environmental fate in these ecosystems is controlled mainly by temperature and biogeochemical processes. Global warming may accelerate the re-emissions and redistribution of POPs among environmental compartments via soil-air exchange. Soil-air exchange is a key process controlling the fate and transportation of POPs and terrestrial ecosystem C at regional and global scales. Soil respiration is one of the largest terrestrial C flux induced by microbe and plant metabolism, which can affect POPs biotransformation in terrestrial ecosystems. Carbon flow through food web structure also may have important consequences for the biomagnification of POPs in the ecosystems and further lead to biodiversity loss induced by climate change and POPs pollution stress. Moreover, the integrated techniques and biological adaptation strategy help to fully explore the coupling mechanisms, functioning and trends of POPs and C and nutrient biogeochemical cycling processes in terrestrial ecosystems. There is increasing evidence that the environmental fate of POPs has been linked with biogeochemical cycles of C and nutrients in terrestrial ecosystems under GCC. However, the relationships between POPs and the biogeochemical cycles of C and nutrients are still not well understood. Further

  16. Contrasting responses of water use efficiency to drought across global terrestrial ecosystems.

    Science.gov (United States)

    Yang, Yuting; Guan, Huade; Batelaan, Okke; McVicar, Tim R; Long, Di; Piao, Shilong; Liang, Wei; Liu, Bing; Jin, Zhao; Simmons, Craig T

    2016-03-17

    Drought is an intermittent disturbance of the water cycle that profoundly affects the terrestrial carbon cycle. However, the response of the coupled water and carbon cycles to drought and the underlying mechanisms remain unclear. Here we provide the first global synthesis of the drought effect on ecosystem water use efficiency (WUE = gross primary production (GPP)/evapotranspiration (ET)). Using two observational WUE datasets (i.e., eddy-covariance measurements at 95 sites (526 site-years) and global gridded diagnostic modelling based on existing observation and a data-adaptive machine learning approach), we find a contrasting response of WUE to drought between arid (WUE increases with drought) and semi-arid/sub-humid ecosystems (WUE decreases with drought), which is attributed to different sensitivities of ecosystem processes to changes in hydro-climatic conditions. WUE variability in arid ecosystems is primarily controlled by physical processes (i.e., evaporation), whereas WUE variability in semi-arid/sub-humid regions is mostly regulated by biological processes (i.e., assimilation). We also find that shifts in hydro-climatic conditions over years would intensify the drought effect on WUE. Our findings suggest that future drought events, when coupled with an increase in climate variability, will bring further threats to semi-arid/sub-humid ecosystems and potentially result in biome reorganization, starting with low-productivity and high water-sensitivity grassland.

  17. Linking Biological Responses of Terrestrial N Eutrophication to the Final Ecosystem Goods and Services Classification System

    Science.gov (United States)

    Bell, M. D.; Clark, C.; Blett, T.

    2015-12-01

    The response of a biological indicator to N deposition can indicate that an ecosystem has surpassed a critical load and is at risk of significant change. The importance of this exceedance is often difficult to digest by policy makers and public audiences if the change is not linked to a familiar ecosystem endpoint. A workshop was held to bring together scientists, resource managers, and policy makers with expertise in ecosystem functioning, critical loads, and economics in an effort to identify the ecosystem services impacted by air pollution. This was completed within the framework of the Final Ecosystem Goods and Services (FEGS) Classification System to produce a product that identified distinct interactions between society and the effects of nitrogen pollution. From each change in a biological indicator, we created multiple ecological production functions to identify the cascading effects of the change to a measureable ecosystem service that a user interacts with either by enjoying, consuming, or appreciating the good or service, or using it as an input in the human economy. This FEGS metric was then linked to a beneficiary group that interacts with the service. Chains detailing the links from the biological indicator to the beneficiary group were created for aquatic and terrestrial acidification and eutrophication at the workshop, and here we present a subset of the workshop results by highlighting for 9 different ecosystems affected by terrestrial eutrophication. A total of 213 chains that linked to 37 unique FEGS metrics and impacted 15 beneficiary groups were identified based on nitrogen deposition mediated changes to biological indicators. The chains within each ecosystem were combined in flow charts to show the complex, overlapping relationships among biological indicators, ecosystem services, and beneficiary groups. Strength of relationship values were calculated for each chain based on support for the link in the scientific literature. We produced the

  18. Global Terrestrial Ecosystem Observations: Why, Where, What and How?

    NARCIS (Netherlands)

    Jongman, R.H.G.; Skidmore, A.K.; Mücher, C.A.; Bunce, R.G.H.; Metzger, M.

    2017-01-01

    This chapter covers the questions of ecosystem definition and the organisation of a monitoring system. It treats where and how ecosystems should be measured and the integration between in situ and RS observations. Ecosystems are characterised by composition, function and structure. The ecosystem

  19. Relations between vegetation and water level in groundwaterdependent terrestrial ecosystems (GWDTEs)

    DEFF Research Database (Denmark)

    Johansen, Ole Munch; Andersen, Dagmar Kappel; Ejrnaes, Rasmus

    2018-01-01

    Alkaline wetlands and fens are groundwater dependent, terrestrial ecosystems (GWDTEs) existing throughout the temperate zone. They contain a large number of protected and endangered plant species and their ecological status is threatened by insufficient groundwater quality and quantity. However...

  20. A terrestrial ecosystem model (SOLVEG) coupled with atmospheric gas and aerosol exchange processes

    International Nuclear Information System (INIS)

    Katata, Genki; Ota, Masakazu

    2017-01-01

    In order to predict the impact of atmospheric pollutants (gases and aerosols) to the terrestrial ecosystem, new schemes for calculating the processes of dry deposition of gases and aerosols, and water and carbon cycles in terrestrial ecosystems were implemented in the one-dimensional atmosphere-SOiL-VEGetation model, SOLVEG. We made performance tests at various vegetation areas to validate the newly developed schemes. In this report, the detail in each modeled process is described with an instruction how to use the modified SOLVEG. The framework of 'terrestrial ecosystem model' was developed for investigation of a change in water, energy, and carbon cycles associated with global warming and air pollution and its impact on terrestrial ecosystems. (author)

  1. Dual role of lignin in plant litter decomposition in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Ballaré, Carlos L

    2010-03-09

    Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems.

  2. The Limits of Acclimation of land plants in a Terrestrial Ecosystems Model

    Science.gov (United States)

    Kothavala, Zavareh

    2014-05-01

    In this study, we examine the role of the terrestrial carbon cycle and the ability of different plant types to acclimate to a changing climate at the centennial scale using a global ecosystems model with updated biogeochemical processes related to moisture, carbon, and nitrogen. Elevated level of atmospheric carbon dioxide (CO2) increases CO2 fertilization, resulting in more CO2 uptake by vegetation, whereas the concomitant warming increases autotrophic and heterotrophic respiration, releasing CO2 to the atmosphere. Additionally, warming will enhance photosynthesis if current temperatures are below the optimal temperature for plant growth, while it will reduce photosynthesis if current temperatures are above the optimal temperature for plant growth. We present a series of ensemble simulations to evaluate the ability of plants to acclimate to changing conditions over the last century and how this affects the terrestrial carbon sink. A set of experiments related to (a) the varying relationship between CO2 fertilization and the half saturation constant, (b) the factors related to gross primary productivity and maintenance respiration, and (c) the variables related to heterotrophic respiration, were conducted with thirteen plant functional types. The experiments were performed using the Terrestrial Ecosystem Model (TEM) with a present-day vegetation distribution without the effects of natural or human disturbance, and a closed Nitrogen cycle, at a half-degree resolution over the globe. The experiment design consisted of eight scenarios that are consistent with past and future ecosystem conditions, presented in other scientific studies. The significance of model trends related to runoff, soil moisture, soil carbon, Net Primary Productivity (NPP), crop yield, and Net Ecosystem Productivity (NEP) for different seasons, as well as surface temperature, precipitation, vapor pressure, and photosynthetically active radiation are analyzed for various ecosystems at the global

  3. Carbon fluxes, evapotranspiration, and water use efficiency of terrestrial ecosystems in China

    Science.gov (United States)

    Jingfeng Xiao; Ge Sun; Jiquan Chen; Hui Chen; Shiping Chen; Gang Dong

    2013-01-01

    The magnitude, spatial patterns, and controlling factors of the carbon and water fluxes of terrestrial ecosystems in China are not well understood due to the lack of ecosystem-level flux observations. We synthesized flux and micrometeorological observations from 22 eddy covariance flux sites across China,and examined the carbon fluxes, evapotranspiration (ET), and...

  4. Turbulence and Fluid Flow: Perspectives. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Simpson, James R.

    This module is part of a series on Physical Processes in Terrestrial and Aquatic Ecosystems. The materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process.…

  5. Microplastics in the terrestrial ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae)

    NARCIS (Netherlands)

    Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.D.; Salanki, T.E.; Ploeg, van der M.J.C.; Besseling, E.; Koelmans, A.A.; Geissen, V.

    2016-01-01

    Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, <150 μm)

  6. The adaptation rate of terrestrial ecosystems as a critical factor in global climate dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fuessler, J.S.; Gassmann, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    A conceptual climate model describing regional two-way atmosphere-vegetation interaction has been extended by a simple qualitative scheme of ecosystem adaptation to drought stress. The results of this explorative study indicate that the role of terrestrial vegetation under different forcing scenarios depends crucially on the rate of the ecosystems adaptation to drought stress. The faster the adaptation of important ecosystems such as forests the better global climate is protected from abrupt climate changes. (author) 1 fig., 3 refs.

  7. Importance of terrestrial arthropods as subsidies in lowland Neotropical rain forest stream ecosystems

    Science.gov (United States)

    Small, Gaston E.; Torres, Pedro J.; Schwizer, Lauren M.; Duff, John H.; Pringle, Catherine M.

    2013-01-01

    The importance of terrestrial arthropods has been documented in temperate stream ecosystems, but little is known about the magnitude of these inputs in tropical streams. Terrestrial arthropods falling from the canopy of tropical forests may be an important subsidy to tropical stream food webs and could also represent an important flux of nitrogen (N) and phosphorus (P) in nutrient-poor headwater streams. We quantified input rates of terrestrial insects in eight streams draining lowland tropical wet forest in Costa Rica. In two focal headwater streams, we also measured capture efficiency by the fish assemblage and quantified terrestrially derived N- and P-excretion relative to stream nutrient uptake rates. Average input rates of terrestrial insects ranged from 5 to 41 mg dry mass/m2/d, exceeding previous measurements of aquatic invertebrate secondary production in these study streams, and were relatively consistent year-round, in contrast to values reported in temperate streams. Terrestrial insects accounted for half of the diet of the dominant fish species, Priapicthys annectens. Although terrestrially derived fish excretion was found to be a small flux relative to measured nutrient uptake rates in the focal streams, the efficient capture and processing of terrestrial arthropods by fish made these nutrients available to the local stream ecosystem. This aquatic-terrestrial linkage is likely being decoupled by deforestation in many tropical regions, with largely unknown but potentially important ecological consequences.

  8. Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems

    CSIR Research Space (South Africa)

    Schimel, DS

    2001-11-08

    Full Text Available Knowledge of carbon exchange between the atmosphere, land and the oceans is important, given that the terrestrial and marine environments are currently absorbing about half of the carbon dioxide that is emitted by fossil-fuel combustion. This carbon...

  9. Implications of Uncertainty in Fossil Fuel Emissions for Terrestrial Ecosystem Modeling

    Science.gov (United States)

    King, A. W.; Ricciuto, D. M.; Mao, J.; Andres, R. J.

    2017-12-01

    Given observations of the increase in atmospheric CO2, estimates of anthropogenic emissions and models of oceanic CO2 uptake, one can estimate net global CO2 exchange between the atmosphere and terrestrial ecosystems as the residual of the balanced global carbon budget. Estimates from the Global Carbon Project 2016 show that terrestrial ecosystems are a growing sink for atmospheric CO2 (averaging 2.12 Gt C y-1 for the period 1959-2015 with a growth rate of 0.03 Gt C y-1 per year) but with considerable year-to-year variability (standard deviation of 1.07 Gt C y-1). Within the uncertainty of the observations, emissions estimates and ocean modeling, this residual calculation is a robust estimate of a global terrestrial sink for CO2. A task of terrestrial ecosystem science is to explain the trend and variability in this estimate. However, "within the uncertainty" is an important caveat. The uncertainty (2σ; 95% confidence interval) in fossil fuel emissions is 8.4% (±0.8 Gt C in 2015). Combined with uncertainty in other carbon budget components, the 2σ uncertainty surrounding the global net terrestrial ecosystem CO2 exchange is ±1.6 Gt C y-1. Ignoring the uncertainty, the estimate of a general terrestrial sink includes 2 years (1987 and 1998) in which terrestrial ecosystems are a small source of CO2 to the atmosphere. However, with 2σ uncertainty, terrestrial ecosystems may have been a source in as many as 18 years. We examine how well global terrestrial biosphere models simulate the trend and interannual variability of the global-budget estimate of the terrestrial sink within the context of this uncertainty (e.g., which models fall outside the 2σ uncertainty and in what years). Models are generally capable of reproducing the trend in net terrestrial exchange, but are less able to capture interannual variability and often fall outside the 2σ uncertainty. The trend in the residual carbon budget estimate is primarily associated with the increase in atmospheric CO2

  10. The impacts of past climate change on terrestrial and aquatic ecosystems

    International Nuclear Information System (INIS)

    Bradshaw, R.H.W.; Anderson, N.J.

    2001-01-01

    The last two million years of global history have been dominated by the impacts of rapid climate change. This influence is not immediately obvious to most biologists whose observations rarely extend beyond a period of a few years, but becomes apparent when interpreting long-term data sets whether they be population studies or palaeoecological data. It is appropriate therefore to consider how terrestrial and aquatic ecosystems have responded to climate change during the Quaternary when speculating about response to future climatic developments. In this chapter we discuss and illustrate the complex interactions between climate and anthropogenic influence on terrestrial and aquatic ecosystems during the Holocene. Climate influences ecosystems both directly (e.g. physiological responses or lake thermal stratification) and indirectly (e.g. via fire frequency or catchment hydrology). Lake sediments can be used to study both past climatic change directly and the effects of past climatic variability. In this chapter we present summary examples of the influence of past climate change on terrestrial and aquatic ecosystems as well showing how lake sediment records can provide proxy records of past climate change. The geological record from the last 18 000 years documents large changes in terrestrial and aquatic ecosystems that are primarily driven by climatic change, but are modified by internal ecosystem processes. These changes are comparable in magnitude and rapidity to those predicted for the near future. Species at their distributional limits are particularly sensitive to climate change and contractions of range can be sudden in response to extreme climatic events such as the storm of December 1999 that damaged Picea trees far more than tree species that lay within their natural range limits. Palaeoecological records provide compelling evidence for direct climate forcing of aquatic and terrestrial ecosystems but importantly also permit comparative analyses of impacts

  11. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change

    Science.gov (United States)

    McCluney, Kevin E.; Belnap, Jayne; Collins, Scott L.; González, Angélica L.; Hagen, Elizabeth M.; Holland, J. Nathaniel; Kotler, Burt P.; Maestre, Fernando T.; Smith, Stanley D.; Wolf, Blair O.

    2012-01-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  12. Using the CARDAMOM framework to retrieve global terrestrial ecosystem functioning properties

    Science.gov (United States)

    Exbrayat, Jean-François; Bloom, A. Anthony; Smallman, T. Luke; van der Velde, Ivar R.; Feng, Liang; Williams, Mathew

    2016-04-01

    Terrestrial ecosystems act as a sink for anthropogenic emissions of fossil-fuel and thereby partially offset the ongoing global warming. However, recent model benchmarking and intercomparison studies have highlighted the non-trivial uncertainties that exist in our understanding of key ecosystem properties like plant carbon allocation and residence times. It leads to worrisome differences in terrestrial carbon stocks simulated by Earth system models, and their evolution in a warming future. In this presentation we attempt to provide global insights on these properties by merging an ecosystem model with remotely-sensed global observations of leaf area and biomass through a data-assimilation system: the CARbon Data MOdel fraMework (CARDAMOM). CARDAMOM relies on a Markov Chain Monte Carlo algorithm to retrieve confidence intervals of model parameters that regulate ecosystem properties independently of any prior land-cover information. The MCMC method thereby enables an explicit representation of the uncertainty in land-atmosphere fluxes and the evolution of terrestrial carbon stocks through time. Global experiments are performed for the first decade of the 21st century using a 1°×1° spatial resolution. Relationships emerge globally between key ecosystem properties. For example, our analyses indicate that leaf lifespan and leaf mass per area are highly correlated. Furthermore, there exists a latitudinal gradient in allocation patterns: high latitude ecosystems allocate more carbon to photosynthetic carbon (leaves) while plants invest more carbon in their structural parts (wood and root) in the wet tropics. Overall, the spatial distribution of these ecosystem properties does not correspond to usual land-cover maps and are also partially correlated with disturbance regimes. For example, fire-prone ecosystems present statistically significant higher values of carbon use efficiency than less disturbed ecosystems experiencing similar climatic conditions. These results

  13. Impacts of Climate Chnage on Terrestrial Ecosystems Functioning - An Overview

    DEFF Research Database (Denmark)

    Beier, Claus; Ambus, Per; Amdal, M. F.

    ecosystems (IPCC, 2013) with major impacts on naturalenvironments as well as ecosystems used for agriculture or forestry. Over the past three decades, major efforts have been devoted to understandand predict such impacts of climate change on ecosystemprocesses and functioning in order to understand...... to climate change and experimentationis the time scale. Climate change acts over decades, meaningthat climate change experiments running for 2-4 years only highlightshort term and transient effects on the ecosystems, while lackingthe ability to inform about long term and more stable effects.The "long term...... mimicking future climate changes, and dynamicecosystem modelling (Beier, 2004; Rustad, 2008). Each of theseapproaches has their forces and drawbacks, but across all a generallimitation is that observations and experiments have focused on onesingle climate factor. For example, observations across gradients...

  14. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. SR-Site Biosphere

    International Nuclear Information System (INIS)

    Loefgren, Anders

    2010-12-01

    The ecosystem is in most cases the link between radionuclides released from a repository and the exposure of humans and other biota to them. This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing and performing cross-disciplinary analyses of data from a large number of reports produced during the site investigations, Figure 1-2. The report describes the terrestrial landscape, divided here into the three main categories: forests, wetlands and agriculture land, by identifying properties that are important for element accumulation and transport

  15. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. SR-Site Biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Anders (ed.) (EcoAnalytica, Haegersten (Sweden))

    2010-12-15

    The ecosystem is in most cases the link between radionuclides released from a repository and the exposure of humans and other biota to them. This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing and performing cross-disciplinary analyses of data from a large number of reports produced during the site investigations, Figure 1-2. The report describes the terrestrial landscape, divided here into the three main categories: forests, wetlands and agriculture land, by identifying properties that are important for element accumulation and transport

  16. Terrestrial carbon and intraspecific size-variation shape lake ecosystems

    NARCIS (Netherlands)

    Jansson, M.; Persson, L.; de Roos, A.M.; I. Jones, R.; Tranvik, L.J.

    2007-01-01

    Conceptual models of lake ecosystem structure and function have generally assumed that energy in pelagic systems is derived from in situ photosynthesis and that its use by higher trophic levels depends on the average properties of individuals in consumer populations. These views are challenged by

  17. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems

    Science.gov (United States)

    Victor Resco de Dios; Michael L. Goulden; Kiona Ogle; Andrew D. Richardson; David Y. Hollinger; Eric A. Davidson; Josu G. Alday; Greg A. Barron-Gafford; Arnaud Carrara; Andrew S. Kowalski; Walt C. Oechel; Borja R. Reverter; Russell L. Scott; Ruth K. Varner; Ruben Diaz-Sierra; Jose M. Moreno

    2012-01-01

    It is often assumed that daytime patterns of ecosystem carbon assimilation are mostly driven by direct physiological responses to exogenous environmental cues. Under limited environmental variability, little variation in carbon assimilation should thus be expected unless endogenous plant controls on carbon assimilation, which regulate photosynthesis in time, are active...

  18. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Czech Academy of Sciences Publication Activity Database

    Song, B.; Niu, S.; Luo, R.; Chen, J.; Yu, G.; Olejnik, Janusz; Wohlfahrt, G.; Kiely, G.; Noormels, A.; Montagnani, L.; Cescatti, A.; Magliulo, V.; Law, B. E.; Lund, M.; Varlagin, A.; Raschi, A.; Peichl, M.; Nilsson, M.; Merbold, L.

    2014-01-01

    Roč. 7, č. 5 (2014), s. 419-428 ISSN 1752-9921 Institutional support: RVO:67179843 Keywords : activation energy * ecosystem respiration * index of water availability * gross primary productivity Subject RIV: EH - Ecology, Behaviour Impact factor: 2.646, year: 2014

  19. [Effects and mechanism of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem].

    Science.gov (United States)

    Wang, Li-qin; Qi, Yu-chun; Dong, Yun-she; Peng, Qin; Guo, Shu-fang; He, Yun-long; Yan, Zhong-qing

    2015-11-01

    As a widespread natural phenomenon in the soil of middle and high latitude as well as high altitude, freeze-thawing cycles have a great influence on the nitrogen cycle of terrestrial ecosystem in non-growing season. Freeze-thawing cycles can alter the physicochemical and biological properties of the soil, which thereby affect the migration and transformation of soil nitrogen. The impacts of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem found in available studies remain inconsistent, the mechanism is still not clear, and the research methods also need to be further explored and innovated. So it is necessary to sum up and analyze the existing achievements in order to better understand the processes of soil nitrogen cycle subjected to freeze-thawing cycles. This paper reviewed the research progress in China and abroad about the effects and mechanisms of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem, including mineralization, immobilization, nitrification and denitrification, N leakage and gaseous loss, and analyzed the deficiencies of extant research. The possible key research topics that should be urgently paid more attention to in the future were also discussed.

  20. Do global change experiments overestimate impacts on terrestrial ecosystems?

    DEFF Research Database (Denmark)

    Leuzinger, Sebastian; Luo, Yiqi; Beier, Claus

    2011-01-01

    In recent decades, many climate manipulation experiments have investigated biosphere responses to global change. These experiments typically examined effects of elevated atmospheric CO2, warming or drought (driver variables) on ecosystem processes such as the carbon and water cycle (response...... of the responses to decline with higher-order interactions, longer time periods and larger spatial scales. This means that on average, both positive and negative global change impacts on the biosphere might be dampened more than previously assumed....... variables). Because experiments are inevitably constrained in the number of driver variables tested simultaneously, as well as in time and space, a key question is how results are scaled up to predict net ecosystem responses. In this review, we argue that there might be a general trend for the magnitude...

  1. Measuring resilience and assessing vulnerability of terrestrial ecosystems to climate change in South America.

    Science.gov (United States)

    Anjos, Luciano J S; de Toledo, Peter Mann

    2018-01-01

    Climate change has been identified as the primary threat to the integrity and functioning of ecosystems in this century, although there is still much uncertainty about its effects and the degree of vulnerability for different ecosystems to this threat. Here we propose a new methodological approach capable of measuring and mapping the resilience of terrestrial ecosystems at large scales based on their climatic niche. To do this, we used high spatial resolution remote sensing data and ecological niche modeling techniques to calculate and spatialize the resilience of three stable states of ecosystems in South America: forest, savanna, and grassland. Also, we evaluated the sensitivity of ecosystems to climate stress, the likelihood of exposure to non-analogous climatic conditions, and their respective adaptive capacities in the face of climate change. Our results indicate that forests, the most productive and biodiverse terrestrial ecosystems on the earth, are more vulnerable to climate change than savannas or grasslands. Forests showed less resistance to climate stress and a higher chance of exposure to non-analogous climatic conditions. If this scenario occurs, the forest ecosystems would have less chance of adaptation compared to savannas or grasslands because of their narrow climate niche. Therefore, we can conclude that a possible consolidation of non-analogous climatic conditions would lead to a loss of resilience in the forest ecosystem, significantly increasing the chance of a critical transition event to another stable state with a lower density of vegetation cover (e.g., savanna or grassland).

  2. Sensitivity of global terrestrial ecosystems to climate variability.

    Science.gov (United States)

    Seddon, Alistair W R; Macias-Fauria, Marc; Long, Peter R; Benz, David; Willis, Kathy J

    2016-03-10

    The identification of properties that contribute to the persistence and resilience of ecosystems despite climate change constitutes a research priority of global relevance. Here we present a novel, empirical approach to assess the relative sensitivity of ecosystems to climate variability, one property of resilience that builds on theoretical modelling work recognizing that systems closer to critical thresholds respond more sensitively to external perturbations. We develop a new metric, the vegetation sensitivity index, that identifies areas sensitive to climate variability over the past 14 years. The metric uses time series data derived from the moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index, and three climatic variables that drive vegetation productivity (air temperature, water availability and cloud cover). Underlying the analysis is an autoregressive modelling approach used to identify climate drivers of vegetation productivity on monthly timescales, in addition to regions with memory effects and reduced response rates to external forcing. We find ecologically sensitive regions with amplified responses to climate variability in the Arctic tundra, parts of the boreal forest belt, the tropical rainforest, alpine regions worldwide, steppe and prairie regions of central Asia and North and South America, the Caatinga deciduous forest in eastern South America, and eastern areas of Australia. Our study provides a quantitative methodology for assessing the relative response rate of ecosystems--be they natural or with a strong anthropogenic signature--to environmental variability, which is the first step towards addressing why some regions appear to be more sensitive than others, and what impact this has on the resilience of ecosystem service provision and human well-being.

  3. Evaluation of the Terrestrial Ecosystem Formation and Diversity in a Modified Dynamic Global Vegetation Model

    Science.gov (United States)

    Zeng, X.; Shao, P.; Song, X.

    2010-12-01

    Terrestrial ecosystem formation and diversity have great impact on the stability and frangibility of ecosystem. It is important that Dynamic Global Vegetation Models (DGVMs) can capture these essential properties so that they can correctly simulate the succession and transition of terrestrial ecosystem in company with the global climate change. Previous studies have shown that DGVMs can roughly reproduce the spatial distributions of different vegetation types as well as the dependence of the vegetation distribution on climate conditions, however, the capability of DGVMs to reproduce the global vegetation distribution and ecosystem formation has not been fully evaluated. This study is based on our modified DGVM coupled with the Community Land Model (CLM-DGVM). The modified CLM-DGVM can simulate 12 plant functional types (PFTs) besides the bare soil. It allows two or more PFTs coexisting in a grid cell, in contrast to the DGVMs which tend to generate the ecosystem with single dominant plant functional type and hence lose the functional diversity of ecosystem. Our results show that the density distributions of fractional coverage (DDFC) of three vegetation categories (e.g., forest, grassland, and shrubland) and PFTs are different with the observation. In particular, the model overestimates the DDFC over regions with tree coverage larger than 70%, but underestimates the DDFC over regions with tree coverage less than 40%. Furthermore, the functional diversity of PFTs in each gridcell is generally lower than that in the observation. Sensitivity tests show that substantial changes in the terrestrial ecosystem usually occur within the areas where two or more PFTs coexist with comparable fractions, i.e., and the functional diversity is high. These results imply that current CLM-DGVM may not be able to appropriately produce the averaged amplitude and spatial pattern of the transition in global ecosystem. Therefore, we suggest that extensive studies are required to improve

  4. [Assessment of shallow groundwater nitrate concentrations in typical terrestrial ecosystems of Chinese Ecosystem Research Network (CERN) during 2004-2009].

    Science.gov (United States)

    Xu, Zhi-Wei; Zhang, Xin-Yu; Sun, Xiao-Min; Yuan, Guo-Fu; Wang, Sheng-Zhong; Liu, Wen-Hua

    2011-10-01

    The nitrate-N (NO3(-) -N) concentrations of 38 shallow groundwater wells from 31 of the typical terrestrial ecosystems on Chinese Ecosystem Research Network (CERN) were assessed using the monitoring data from 2004 to 2009. The results showed that the average values of NO3(-) -N concentrations were significantly higher in the agricultural (4.85 mg x L(-1) +/- 0.42 mg x L(-1)), desert (oasis) (3.72 mg x L(-1) +/- 0.42 mg x L(-1)) and urban ecosystems (3.77 mg x L(-1) 0.51 mg x L(-1)) than in the grass (1.59 mg x L(-1) +/- 0.35 mg L(-1)) and forest ecosystems (0.39 mg x L(-1) +/- 0.03 mg x L(-1)). Nitrate was the major form of nitrogen, with between 56% to 88% of nitrogen in the nitrate-N form in the shallow groundwater of desert (oasis), urban and agricultural ecosystems. Nitrate-N concentrations for some agricultural ecosystems (Ansai, Yanting, Yucheng) and desert (oasis) ecosystems (Cele, Linze, Akesu) analysis exceeded the 10 mg x L(-1) World Health Organization drinking water standards between 14.3% and 84.6%. Significant seasonality was found in Ansai, Fengqiu, Yanting agricultural ecosystems and the Beijing urban ecosystem using the relatively high frequency monitoring data, with the higher nitrate concentrations usually found during summer and winter months. The monitoring results indicated that the shallow groundwater of agricultural ecosystems was contaminated by agricultural management practices, i.e. fertilization, while the shallow groundwater of forest ecosystems was under natural condition with no contamination from human activities.

  5. Naturalization of host-dependent microbes after introduction into terrestrial ecosystems [Chapter 5

    Science.gov (United States)

    Geral I. McDonald; Paul J. Zambino; Ned B. Klopfenstein

    2005-01-01

    Introduction of plant pathogens, insects, parasites, and predators into terrestrial and marine ecosystems is second only to habitat loss among major threats to biodiversity (Torchin et. al. 2002), and the frequency of introductions continues to increase (Flather et al. 1998, Torchin et al. 2002, Wilcove et al. 1998). Despite their detrimental impacts, introductions can...

  6. The response of terrestrial ecosystems to global climate change: Towards an integrated approach

    Science.gov (United States)

    Lindsey E. Rustad

    2008-01-01

    Accumulating evidence points to an anthropogenic 'fingerprint' on the global climate change that has occurred in the last century. Climate change has, and will continue to have, profound effects on the structure and function of terrestrial ecosystems. As such, there is a critical need to continue to develop a sound scientific basis for national and...

  7. Reconciling the role of terrestrial leaves in pond food webs: a whole-ecosystem experiment.

    Science.gov (United States)

    Holgerson, Meredith A; Post, David M; Skelly, David K

    2016-07-01

    Terrestrial carbon and nutrients can subsidize the detrital pool of freshwater ecosystems; yet, the importance of terrestrial subsidies to lake and pond food webs is uncertain and debated. Terrestrial detritus is expected to have the greatest impact on food webs when water bodies are small and shallow with low levels of incident light. Temporary forested ponds fit this description and are often assumed to have a leaf detritus-based food web, but this has not been quantified. In a whole-ecosystem experiment, we traced the flow of isotopically enriched leaf litter to primary producers and consumers in a small, forested pond. We found that terrestrial leaves provided nutrients to algae, offering an indirect pathway in which leaf litter can enter the food web. Terrestrial leaves were also consumed directly, and larval caddisfly (Limnephilus sp.) shredders likely mobilized leaf nutrients to other consumers, a process overlooked in many previous small-scale experiments that did not incorporate shredders. Unexpectedly, most consumers relied heavily upon algal food pathways despite low light and net heterotrophic conditions. Overall, our study highlights the interconnectedness of algal and leaf litter pathways in small pond food webs, and emphasizes that algal pathways are prevalent and important even in small, shaded ponds with high loads of terrestrial leaf litter. © 2016 by the Ecological Society of America.

  8. Hyperspectral Remote Sensing of Terrestrial Ecosystem Productivity from ISS

    Science.gov (United States)

    Huemmrich, K. F.; Campbell, P. K. E.; Gao, B. C.; Flanagan, L. B.; Goulden, M.

    2017-12-01

    Data from the Hyperspectral Imager for Coastal Ocean (HICO), mounted on the International Space Station (ISS), were used to develop and test algorithms for remotely retrieving ecosystem productivity. The ISS orbit introduces both limitations and opportunities for observing ecosystem dynamics. Twenty six HICO images were used from four study sites representing different vegetation types: grasslands, shrubland, and forest. Gross ecosystem production (GEP) data from eddy covariance were matched with HICO-derived spectra. Multiple algorithms were successful relating spectral reflectance with GEP, including: Spectral Vegetation Indices (SVI), SVI in a light use efficiency model framework, spectral shape characteristics through spectral derivatives and absorption feature analysis, and statistical models leading to Multiband Hyperspectral Indices (MHI) from stepwise regressions and Partial Least Squares Regression (PLSR). Algorithms were able to achieve r2 better than 0.7 for both GEP at the overpass time and daily GEP. These algorithms were successful using a diverse set of observations combining data from multiple years, multiple times during growing season, different times of day, with different view angles, and different vegetation types. The demonstrated robustness of the algorithms presented in this study over these conditions provides some confidence in mapping spatial patterns of GEP, describing variability within fields as well as the regional patterns based only on spectral reflectance information. The ISS orbit provides periods with multiple observations collected at different times of the day within a period of a few days. Diurnal GEP patterns were estimated comparing the half-hourly average GEP from the flux tower against HICO estimates of GEP (r2=0.87) if morning, midday, and afternoon observations were available for average fluxes in the time period.

  9. Sensitivity of global terrestrial ecosystems to climate variability

    Science.gov (United States)

    Seddon, Alistair W. R.; Macias-Fauria, Marc; Long, Peter R.; Benz, David; Willis, Kathy J.

    2016-03-01

    The identification of properties that contribute to the persistence and resilience of ecosystems despite climate change constitutes a research priority of global relevance. Here we present a novel, empirical approach to assess the relative sensitivity of ecosystems to climate variability, one property of resilience that builds on theoretical modelling work recognizing that systems closer to critical thresholds respond more sensitively to external perturbations. We develop a new metric, the vegetation sensitivity index, that identifies areas sensitive to climate variability over the past 14 years. The metric uses time series data derived from the moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index, and three climatic variables that drive vegetation productivity (air temperature, water availability and cloud cover). Underlying the analysis is an autoregressive modelling approach used to identify climate drivers of vegetation productivity on monthly timescales, in addition to regions with memory effects and reduced response rates to external forcing. We find ecologically sensitive regions with amplified responses to climate variability in the Arctic tundra, parts of the boreal forest belt, the tropical rainforest, alpine regions worldwide, steppe and prairie regions of central Asia and North and South America, the Caatinga deciduous forest in eastern South America, and eastern areas of Australia. Our study provides a quantitative methodology for assessing the relative response rate of ecosystems—be they natural or with a strong anthropogenic signature—to environmental variability, which is the first step towards addressing why some regions appear to be more sensitive than others, and what impact this has on the resilience of ecosystem service provision and human well-being.

  10. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China

    DEFF Research Database (Denmark)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere Abdisa

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling...... and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle....

  11. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

    International Nuclear Information System (INIS)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A.; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. - Highlights: • Meta-analysis was used to address the effects of N addition on C cycle. • N addition caused an large decease in belowground plant C pool. • N-rich and N-limited ecosystems had different responses to N addition. - N addition caused a large decrease in below-ground plant C pool.

  12. User fees across ecosystem boundaries: Are SCUBA divers willing to pay for terrestrial biodiversity conservation?

    Science.gov (United States)

    Roberts, Michaela; Hanley, Nick; Cresswell, Will

    2017-09-15

    While ecological links between ecosystems have been long recognised, management rarely crosses ecosystem boundaries. Coral reefs are susceptible to damage through terrestrial run-off, and failing to account for this within management threatens reef protection. In order to quantify the extent to that coral reef users are willing to support management actions to improve ecosystem quality, we conducted a choice experiment with SCUBA divers on the island of Bonaire, Caribbean Netherlands. Specifically, we estimated their willingness to pay to reduce terrestrial overgrazing as a means to improve reef health. Willingness to pay was estimated using the multinomial, random parameter and latent class logit models. Willingness to pay for improvements to reef quality was positive for the majority of respondents. Estimates from the latent class model determined willingness to pay for reef improvements of between $31.17 - $413.18/year, dependent on class membership. This represents a significant source of funding for terrestrial conservation, and illustrates the potential for user fees to be applied across ecosystem boundaries. We argue that such across-ecosystem-boundary funding mechanisms are an important avenue for future investigation in many connected systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Tracing pyrogenic carbon (PyC) beyond terrestrial ecosystems

    Science.gov (United States)

    Wiedemeier, Daniel B.; Eglinton, Timothy I.; Hanke, Ulrich M.; Schmidt, Michael W. I.

    2015-04-01

    Combustion-derived, pyrogenic carbon (PyC) is a persistent organic carbon fraction. Due to its aromatic and condensed nature (Wiedemeier et al., 2015), it is relatively resistant against chemical and biological degradation in the environment, leading to a comparatively slow turnover, which would support carbon sequestration. PyC is produced on large scales (hundreds of teragrams) in biomass burning events such as wildfires, and by combustion of fossil fuel in industry and traffic. PyC is an inherently terrestrial product and thus has predominantly been investigated in soils and the atmosphere. Much fewer studies are available about the subsequent transport of PyC to rivers and oceans. Recently, awareness has been rising about the mobility of PyC from terrestrial to marine systems and its fate in coastal and abyssal sediments was recognized (Mitra et al, 2014). It is therefore crucial to extend our knowledge about the PyC cycle by tracing PyC through all environmental compartments. By comparing its biogeochemical behavior and budgets to that of other forms of organic carbon, it will eventually be possible to elucidate PyC's total spatiotemporal contribution to carbon sequestration. In this study, we are using a state-of-the-art PyC molecular marker method (Wiedemeier et al., 2013, Gierga et al., 2014) to trace quantity, quality as well as 13C and 14C signature of PyC in selected major river systems around the globe (Godavari, Yellow, Danube, Fraser, Mackenzie and Yukon river). Different size fractions of particulate suspended sediment are being analyzed and compared across a north-south gradient. Previous studies suggested a distinct relationship between the age of plant-derived suspended carbon and the latitude of the river system, indicating slower cycling of plant biomarkers in higher latitudes. We discuss this pattern with respect to PyC, its isotopic signature and quality and the resulting implications for the global carbon and PyC cycle. Gierga et al., 2014

  14. Microbial ecology of Thailand tsunami and non-tsunami affected terrestrials.

    Directory of Open Access Journals (Sweden)

    Naraporn Somboonna

    Full Text Available The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S1, as well as a parallel unaffected terrestrial site, non-tsunami affected (S2. S1 demonstrated unique microbial community patterns than S2. The dendrogram constructed using the prokaryotic profiles supported the unique S1 microbial communities. S1 contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S1. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S1 to largely comprise marine habitat indicating-species.

  15. Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis.

    Science.gov (United States)

    Yue, Kai; Peng, Yan; Peng, Changhui; Yang, Wanqin; Peng, Xin; Wu, Fuzhong

    2016-01-27

    Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition.

  16. Biodiversity of Terrestrial Ecosystems in Tropical to Temperate Australia

    Directory of Open Access Journals (Sweden)

    Raymond L. Specht

    2012-01-01

    Full Text Available During the short period of annual foliage growth in evergreen plant communities, aerodynamic fluxes (frictional, thermal, evaporative in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and leaf attributes in overstorey and understorey strata. The number of leaves produced on each vertical foliage shoot depends on available soil water and nutrients during this growth period. The area of all leaves exposed to solar radiation determines net photosynthetic fixation of the plant community throughout the year. In turn, the species richness (number of species per hectare of both plants and resident vertebrates is determined. The species richness of unicellular algae and small multicellular isopods in permanent freshwater lagoons in Northern Australia may possibly have been increased by radiation released from nearby uranium deposits. Evolution of new angiosperms probably occurred in refugia during periods of extreme drought. When favourable climates were restored, the vegetation expanded to result in high Gamma Biodiversity (number of plant species per region but with each major plant community having essentially the same species richness (number of plant species per hectare. The probable effects of pollution and Global Warming on biodiversity in Australian ecosystems, that experience seasonal drought, are discussed.

  17. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis.

    Science.gov (United States)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-11-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Solar radiation uncorks the lignin bottleneck on plant litter decomposition in terrestrial ecosystems

    Science.gov (United States)

    Austin, A.; Ballare, C. L.; Méndez, M. S.

    2015-12-01

    Plant litter decomposition is an essential process in the first stages of carbon and nutrient turnover in terrestrial ecosystems, and together with soil microbial biomass, provide the principal inputs of carbon for the formation of soil organic matter. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in low rainfall ecosystems; however, the generality of this process as a control on carbon cycling in terrestrial ecosystems is not known, and the indirect effects of photodegradation on biotic stimulation of carbon turnover have been debated in recent studies. We demonstrate that in a wide range of plant species, previous exposure to solar radiation, and visible light in particular, enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility for microbial enzymes to plant litter carbohydrates due to a reduction in lignin content. Photodegradation of plant litter reduces the structural and chemical bottleneck imposed by lignin in secondary cell walls. In litter from woody plant species, specific interactions with ultraviolet radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized positive effect of solar radiation exposure on subsequent microbial activity is mediated by increased accessibility to cell wall polysaccharides, which suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release and the carbon balance in a broad range of terrestrial ecosystems.

  19. Quantifying terrestrial ecosystem carbon dynamics in the Jinsha watershed, Upper Yangtze, China from 1975 to 2000

    Science.gov (United States)

    Zhao, Shuqing; Liu, Shuguang; Yin, Runsheng; Li, Zhengpeng; Deng, Yulin; Tan, Kun; Deng, Xiangzheng; Rothstein, David; Qi, Jiaguo

    2010-01-01

    Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China’s upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.

  20. Byers Peninsula: A reference site for coastal, terrestrial and limnetic ecosystem studies in maritime Antarctica

    Science.gov (United States)

    Quesada, A.; Camacho, A.; Rochera, C.; Velázquez, D.

    2009-11-01

    This article describes the development of an international and multidisciplinary project funded by the Spanish Polar Programme on Byers Peninsula (Livingston Island, South Shetlands). The project adopted Byers Peninsula as an international reference site for coastal and terrestrial (including inland waters) research within the framework of the International Polar Year initiative. Over 30 scientists from 12 countries and 26 institutions participated in the field work, and many others participated in the processing of the samples. The main themes investigated were: Holocene changes in climate, using both lacustrine sediment cores and palaeo-nests of penguins; limnology of the lakes, ponds, rivers and wetlands; microbiology of microbial mats, ecology of microbial food webs and viral effects on aquatic ecosystems; ornithology, with investigations on a Gentoo penguin rookery ( Pygoscelis papua) as well as the flying ornithofauna; biocomplexity and life cycles of species from different taxonomic groups; analysis of a complete watershed unit from a landscape perspective; and human impacts, specifically the effect of trampling on soil characteristics and biota. Byers Peninsula offers many features as an international reference site given it is one of the largest ice-free areas in the Antarctic Peninsula region, it has a variety of different landscape units, and it hosts diverse aquatic ecosystems. Moreover, the Byers Peninsula is a hotspot for Antarctic biodiversity, and because of its high level of environmental protection, it has been very little affected by human activities. Finally, the proximity to the Spanish polar installations on Livingston Island and the experience derived from previous expeditions to the site make it logistically feasible as a site for ongoing monitoring and research.

  1. Landscape cultivation alters δ30Si signature in terrestrial ecosystems

    Science.gov (United States)

    Vandevenne, Floor; Delvaux, Claire; Hughes, Harold; Ronchi, Benedicta; Clymans, Wim; Barao, Ana Lucia; Govers, Gerard; Cornelis, Jean Thomas; André, Luc; Struyf, Eric

    2015-04-01

    Despite increasing recognition of the importance of biological Si cycling in controlling dissolved Si (DSi) in soil and stream water, effects of human cultivation on the Si cycle remain poorly understood. Sensitive tracer techniques to identify and quantify Si in the soil-plant-water system could be highly relevant in addressing these uncertainties. Stable Si isotopes are promising tools to define Si sources and sinks along the ecosystem flow path, as intense fractionation occurs during chemical weathering and uptake of dissolved Si in plants. Yet they remain underexploited in the end product of the soil-plant system: the soil water. Here, stable Si isotope ratios (δ30Si) of dissolved Si in soil water were measured along a land use gradient (continuous forest, continuous pasture, young cropland and continuous cropland) with similar parent material (loess) and homogenous bulk mineralogical and climatological (Belgium). Soil water δ30Si signatures are clearly separated along the gradient, with highest average signatures in continuous cropland (+1.61%), intermediate in pasture (+1.05%) and young cropland (+0.89%) and lowest in forest soil water (+0.62%). Our data do not allow distinguishing biological from pedogenic/lithogenic processes, but point to a strong interaction of both. We expect that increasing export of light isotopes in disturbed land uses (i.e. through agricultural harvest), and higher recycling of 28Si and elevated weathering intensity (including clay dissolution) in forest systems will largely determine soil water δ30Si signatures of our systems. Our results imply that soil water δ30Si signature is biased through land management before it reaches rivers and coastal zones, where other fractionation processes take over (e.g. diatom uptake and reverse weathering in floodplains). In particular, a direct role of agriculture systems in lowering export Si fluxes towards rivers and coastal systems has been shown. Stable Si isotopes have a large potential

  2. Modeling Carbon Turnover in Five Terrestrial Ecosystems in the Boreal Zone Using Multiple Criteria of Acceptance

    International Nuclear Information System (INIS)

    Karlberg, Louise; Gustafsson, David; Jansson, Per-Erik

    2006-01-01

    Estimates of carbon fluxes and turnover in ecosystems are key elements in the understanding of climate change and in predicting the accumulation of trace elements in the biosphere. In this paper we present estimates of carbon fluxes and turnover times for five terrestrial ecosystems using a modeling approach. Multiple criteria of acceptance were used to parameterize the model, thus incorporating large amounts of multi-faceted empirical data in the simulations in a standardized manner. Mean turnover times of carbon were found to be rather similar between systems with a few exceptions, even though the size of both the pools and the fluxes varied substantially. Depending on the route of the carbon through the ecosystem, turnover times varied from less than one year to more than one hundred, which may be of importance when considering trace element transport and retention. The parameterization method was useful both in the estimation of unknown parameters, and to identify variability in carbon turnover in the selected ecosystems

  3. Contributions of wildland fire to terrestrial ecosystem carbon dynamics in North America from 1990 to 2012

    Science.gov (United States)

    Chen, Guangsheng; Hayes, Daniel J.; McGuire, A. David

    2017-01-01

    Burn area and the frequency of extreme fire events have been increasing during recent decades in North America, and this trend is expected to continue over the 21st century. While many aspects of the North American carbon budget have been intensively studied, the net contribution of fire disturbance to the overall net carbon flux at the continental scale remains uncertain. Based on national scale, spatially explicit and long-term fire data, along with the improved model parameterization in a process-based ecosystem model, we simulated the impact of fire disturbance on both direct carbon emissions and net terrestrial ecosystem carbon balance in North America. Fire-caused direct carbon emissions were 106.55 ± 15.98 Tg C/yr during 1990–2012; however, the net ecosystem carbon balance associated with fire was −26.09 ± 5.22 Tg C/yr, indicating that most of the emitted carbon was resequestered by the terrestrial ecosystem. Direct carbon emissions showed an increase in Alaska and Canada during 1990–2012 as compared to prior periods due to more extreme fire events, resulting in a large carbon source from these two regions. Among biomes, the largest carbon source was found to be from the boreal forest, primarily due to large reductions in soil organic matter during, and with slower recovery after, fire events. The interactions between fire and environmental factors reduced the fire-caused ecosystem carbon source. Fire disturbance only caused a weak carbon source as compared to the best estimate terrestrial carbon sink in North America owing to the long-term legacy effects of historical burn area coupled with fast ecosystem recovery during 1990–2012.

  4. Conversion of native terrestrial ecosystems in Hawai‘i to novel grazing systems: a review

    Science.gov (United States)

    Leopold, Christina R.; Hess, Steven C.

    2017-01-01

    The remote oceanic islands of Hawai‘i exemplify the transformative effects that non-native herbivorous mammals can bring to isolated terrestrial ecosystems. We reviewed published literature containing systematically collected, analyzed, and peer-reviewed original data specifically addressing direct effects of non-native hoofed mammals (ungulates) on terrestrial ecosystems, and indirect effects and interactions on ecosystem processes in Hawai‘i. The effects of ungulates on native vegetation and ecosystems were addressed in 58 original studies and mostly showed strong short-term regeneration of dominant native trees and understory ferns after ungulate removal, but unassisted recovery was dependent on the extent of previous degradation. Ungulates were associated with herbivory, bark-stripping, disturbance by hoof action, soil erosion, enhanced nutrient cycling from the interaction of herbivory and grasses, and increased pyrogenicity and competition between native plants and pasture grasses. No studies demonstrated that ungulates benefitted native ecosystems except in short-term fire-risk reduction. However, non-native plants became problematic and continued to proliferate after release from herbivory, including at least 11 species of non-native pasture grasses that had become established prior to ungulate removal. Competition from non-native grasses inhibited native species regeneration where degradation was extensive. These processes have created novel grazing systems which, in some cases, have irreversibly altered Hawaii’s terrestrial ecology. Non-native plant control and outplanting of rarer native species will be necessary for recovery where degradation has been extensive. Lack of unassisted recovery in some locations should not be construed as a reason to not attempt restoration of other ecosystems.

  5. Water use efficiency of China's terrestrial ecosystems and responses to drought.

    Science.gov (United States)

    Liu, Yibo; Xiao, Jingfeng; Ju, Weimin; Zhou, Yanlian; Wang, Shaoqiang; Wu, Xiaocui

    2015-09-08

    Water use efficiency (WUE) measures the trade-off between carbon gain and water loss of terrestrial ecosystems, and better understanding its dynamics and controlling factors is essential for predicting ecosystem responses to climate change. We assessed the magnitude, spatial patterns, and trends of WUE of China's terrestrial ecosystems and its responses to drought using a process-based ecosystem model. During the period from 2000 to 2011, the national average annual WUE (net primary productivity (NPP)/evapotranspiration (ET)) of China was 0.79 g C kg(-1) H2O. Annual WUE decreased in the southern regions because of the decrease in NPP and the increase in ET and increased in most northern regions mainly because of the increase in NPP. Droughts usually increased annual WUE in Northeast China and central Inner Mongolia but decreased annual WUE in central China. "Turning-points" were observed for southern China where moderate and extreme droughts reduced annual WUE and severe drought slightly increased annual WUE. The cumulative lagged effect of drought on monthly WUE varied by region. Our findings have implications for ecosystem management and climate policy making. WUE is expected to continue to change under future climate change particularly as drought is projected to increase in both frequency and severity.

  6. Water use efficiency of China’s terrestrial ecosystems and responses to drought

    Science.gov (United States)

    Liu, Yibo; Xiao, Jingfeng; Ju, Weimin; Zhou, Yanlian; Wang, Shaoqiang; Wu, Xiaocui

    2015-01-01

    Water use efficiency (WUE) measures the trade-off between carbon gain and water loss of terrestrial ecosystems, and better understanding its dynamics and controlling factors is essential for predicting ecosystem responses to climate change. We assessed the magnitude, spatial patterns, and trends of WUE of China’s terrestrial ecosystems and its responses to drought using a process-based ecosystem model. During the period from 2000 to 2011, the national average annual WUE (net primary productivity (NPP)/evapotranspiration (ET)) of China was 0.79 g C kg−1 H2O. Annual WUE decreased in the southern regions because of the decrease in NPP and the increase in ET and increased in most northern regions mainly because of the increase in NPP. Droughts usually increased annual WUE in Northeast China and central Inner Mongolia but decreased annual WUE in central China. “Turning-points” were observed for southern China where moderate and extreme droughts reduced annual WUE and severe drought slightly increased annual WUE. The cumulative lagged effect of drought on monthly WUE varied by region. Our findings have implications for ecosystem management and climate policy making. WUE is expected to continue to change under future climate change particularly as drought is projected to increase in both frequency and severity. PMID:26347998

  7. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. Site descriptive modelling SDM site

    International Nuclear Information System (INIS)

    Loefgren, Anders

    2008-12-01

    This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing ecological data and data from disciplines such as hydrology, quaternary geology and chemistry. The description therefore includes a number of different processes that drive element fluxes in the ecosystems, such as net primary production, heterotrophic respiration, transpiration, and horizontal transport from land to streams and lakes. Moreover, the human appropriation of the landscape is described with regard to land use and potential and actual utilization of food resources both today and in a historical perspective

  8. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. Site descriptive modelling SDM site

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Anders (EcoAnalytica, Haegersten (Sweden)) (ed.)

    2008-12-15

    This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing ecological data and data from disciplines such as hydrology, quaternary geology and chemistry. The description therefore includes a number of different processes that drive element fluxes in the ecosystems, such as net primary production, heterotrophic respiration, transpiration, and horizontal transport from land to streams and lakes. Moreover, the human appropriation of the landscape is described with regard to land use and potential and actual utilization of food resources both today and in a historical perspective

  9. Inferring terrestrial photosynthetic light use efficiency of temperate ecosystems from space

    Science.gov (United States)

    Thomas Hilker; Nicholas C. Coops; Forest G. Hall; Caroline J. Nichol; Alexei Lyapustin; T. Andrew Black; Michael A. Wulder; Ray Leuning; Alan Barr; David Y. Hollinger; Bill Munger; Compton J. Tucker

    2011-01-01

    Terrestrial ecosystems absorb about 2.8 Gt C yr−1, which is estimated to be about a quarter of the carbon emitted from fossil fuel combustion. However, the uncertainties of this sink are large, on the order of ±40%, with spatial and temporal variations largely unknown. One of the largest factors contributing to the uncertainty is photosynthesis,...

  10. Linkages Among Water Vapor Flows, Food Production, and Terrestrial Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Johan Rockström

    1999-12-01

    Full Text Available Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3/yr (ranging from 56,000 to 84,000 km3/yr. Of this flow, 90% is attributed to forests, including woodlands (40,000 km3/yr, wetlands (1400 km3/yr, grasslands (15,100 km3/yr, and croplands (6800 km3/yr. These terrestrial biomes sustain society with essential welfare-supporting ecosystem services, including food production. By analyzing the freshwater requirements of an increasing demand for food in the year 2025, we discover a critical trade-off between flows of water vapor for food production and for other welfare-supporting ecosystem services. To reduce the risk of unintentional welfare losses, this trade-off must become embedded in intentional ecohydrological landscape management.

  11. Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Méndez, M Soledad; Ballaré, Carlos L

    2016-04-19

    A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems.

  12. Effects of Climate and Ecosystem Disturbances on Biogeochemical Cycling in a Semi-Natural Terrestrial Ecosystem

    International Nuclear Information System (INIS)

    Beier, Claus; Schmidt, Inger Kappel; Kristensen, Hanne Lakkenborg

    2004-01-01

    The effects of increased temperature and potential ecosystem disturbances on biogeochemical cycling were investigated by manipulation of temperature in a mixed Calluna/grass heathland in Denmark. A reflective curtain covered the vegetation during the night to reduce the heat loss of IR radiation from the ecosystem to the atmosphere. This 'night time warming' was done for 3 years and warmed the air and soil by 1.1 deg. C. Warming was combined with ecosystem disturbances, including infestation by Calluna heather beetles (Lochmaea suturalis Thompson) causing complete defoliation of Calluna leaves during the summer 2000, and subsequent harvesting of all aboveground biomass during the autumn. Small increases in mineralisation rates were induced by warming and resulted in increased leaching of nitrogen from the organic soil layer. The increased nitrogen leaching from the organic soil layer was re-immobilised in the mineral soil layer as warming stimulated plant growth and thereby increased nitrogen immobilisation. Contradictory to the generally moderate effects of warming, the heather beetle infestation had very strong effects on mineralisation rates and the plant community. The grasses completely out-competed the Calluna plants which had not re-established two years after the infestation, probably due to combined effects of increased nutrient availability and the defoliation of Calluna. On the short term, ecosystem disturbances may have very strong effects on internal ecosystem processes and plant community structure compared to the more long-term effects of climate change

  13. Assessing antiquity and turnover of terrestrial ecosystems in eastern North America using fossil pollen data: A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yao; Jackson, Stephen T [Department of Botany and Program in Ecology, University of Wyoming (United States); Brewer, Simon [Department of Botany, University of Wyoming (United States); Williams, John W, E-mail: yliu11@uwyo.ed [Department of Geography and Center for Climatic Research, University of Wisconsin (United States)

    2010-03-15

    We explored formal approaches to identifying and interpreting the antiquity and turnover of terrestrial ecosystems in eastern North America using pollen records. Preliminary results of cluster analyses, receiver-operating characteristic (ROC) analyses, and likelihood estimation of ecosystem analog in a simple Bayesian model allow assessment of modern ecosystem antiquities and past ecosystem turnovers. Approaches discussed in this study thus provide a vehicle for further studies.

  14. Assessing antiquity and turnover of terrestrial ecosystems in eastern North America using fossil pollen data: A preliminary study

    International Nuclear Information System (INIS)

    Liu Yao; Jackson, Stephen T; Brewer, Simon; Williams, John W

    2010-01-01

    We explored formal approaches to identifying and interpreting the antiquity and turnover of terrestrial ecosystems in eastern North America using pollen records. Preliminary results of cluster analyses, receiver-operating characteristic (ROC) analyses, and likelihood estimation of ecosystem analog in a simple Bayesian model allow assessment of modern ecosystem antiquities and past ecosystem turnovers. Approaches discussed in this study thus provide a vehicle for further studies.

  15. Changing Arctic ecosystems--research to understand and project changes in marine and terrestrial ecosystems of the Arctic

    Science.gov (United States)

    Geiselman, Joy; DeGange, Anthony R.; Oakley, Karen; Derksen, Dirk; Whalen, Mary

    2012-01-01

    Ecosystems and their wildlife communities are not static; they change and evolve over time due to numerous intrinsic and extrinsic factors. A period of rapid change is occurring in the Arctic for which our current understanding of potential ecosystem and wildlife responses is limited. Changes to the physical environment include warming temperatures, diminishing sea ice, increasing coastal erosion, deteriorating permafrost, and changing water regimes. These changes influence biological communities and the ways in which human communities interact with them. Through the new initiative Changing Arctic Ecosystems (CAE) the U.S. Geological Survey (USGS) strives to (1) understand the potential suite of wildlife population responses to these physical changes to inform key resource management decisions such as those related to the Endangered Species Act, and (2) provide unique insights into how Arctic ecosystems are responding under new stressors. Our studies examine how and why changes in the ice-dominated ecosystems of the Arctic are affecting wildlife and will provide a better foundation for understanding the degree and manner in which wildlife species respond and adapt to rapid environmental change. Changes to Arctic ecosystems will be felt broadly because the Arctic is a production zone for hundreds of species that migrate south for the winter. The CAE initiative includes three major research themes that span Arctic ice-dominated ecosystems and that are structured to identify and understand the linkages between physical processes, ecosystems, and wildlife populations. The USGS is applying knowledge-based modeling structures such as Bayesian Networks to integrate the work.

  16. Artificial Light at Night Affects Organism Flux across Ecosystem Boundaries and Drives Community Structure in the Recipient Ecosystem

    Directory of Open Access Journals (Sweden)

    Alessandro Manfrin

    2017-10-01

    Full Text Available Artificial light at night (ALAN is a widespread alteration of the natural environment that can affect the functioning of ecosystems. ALAN can change the movement patterns of freshwater animals that move into the adjacent riparian and terrestrial ecosystems, but the implications for local riparian consumers that rely on these subsidies are still unexplored. We conducted a 2-year field experiment to quantify changes of freshwater-terrestrial linkages by installing streetlights in a previously light-naïve riparian area adjacent to an agricultural drainage ditch. We compared the abundance and community composition of emerging aquatic insects, flying insects, and ground-dwelling arthropods with an unlit control site. Comparisons were made within and between years using two-way generalized least squares (GLS model and a BACI design (Before-After Control-Impact. Aquatic insect emergence, the proportion of flying insects that were aquatic in origin, and the total abundance of flying insects all increased in the ALAN-illuminated area. The abundance of several night-active ground-dwelling predators (Pachygnatha clercki, Trochosa sp., Opiliones increased under ALAN and their activity was extended into the day. Conversely, the abundance of nocturnal ground beetles (Carabidae decreased under ALAN. The changes in composition of riparian predator and scavenger communities suggest that the increase in aquatic-to-terrestrial subsidy flux may cascade through the riparian food web. The work is among the first studies to experimentally manipulate ALAN using a large-scale field experiment, and provides evidence that ALAN can affect processes that link adjacent ecosystems. Given the large number of streetlights that are installed along shorelines of freshwater bodies throughout the globe, the effects could be widespread and represent an underestimated source of impairment for both aquatic and riparian systems.

  17. Water use efficiency of net primary production in global terrestrial ecosystems

    Science.gov (United States)

    Xia, Lei; Wang, Fei; Mu, Xingmin; Jin, Kai; Sun, Wenyi; Gao, Peng; Zhao, Guangju

    2015-07-01

    The carbon and water cycles of terrestrial ecosystems, which are strongly coupled via water use efficiency (WUE), are influenced by global climate change. To explore the relationship between the carbon and water cycles and predict the effect of climate change on terrestrial ecosystems, it is necessary to study the WUE in global terrestrial ecosystems. In this study, the 13-year WUE (i.e., net primary production (NPP)/evapotranspiration (ET)) of global terrestrial ecosystems was calculated based on the Moderate Resolution Imaging Spectro-radiometer (MODIS) NPP (MOD17A3) and ET (MOD16A3) products from 2000 to 2012. The results indicate that the annual average WUE decreased but not significantly, and the 13-year mean value was 868.88 mg C m -2 mm -1. The variation trend of WUE value for each pixel differed greatly across the terrestrial ecosystems. A significant variation ( Pincreased from north to south in Africa and Oceania and from east to west in Europe and South America. Both latitudinal and longitudinal gradients existed in Asia and North America. The following trends in the WUE of different continents and Köppen-Geiger climates were observed: Europe (1129.71 mg C m -2 mm -1)> Oceania (1084.46 mg C m -2 mm -1)> Africa (893.51 mg C m -2 mm -1)> South America (893.07 mg C m -2 mm -1)> North America (870.79 mg C m -2 mm -1)> Asia (738.98 mg C m -2 mm -1) and warm temperate climates (1094 mg C m -2 mm -1)> snowy climates (862 mg C m -2 mm -1)> arid climates (785 mg C m -2 mm -1)> equatorial climates (732 mg C m -2 mm -1)> polar climates (435 mg C m -2 mm -1). Based on the WUE value and the present or future rainfall, the maximum carbon that fixed in one region may be theoretically calculated. Also, under the background of global climatic change, WUE may be regarded as an important reference for allotting CO 2 emissions offsets and carbon transactions.

  18. Bayesian calibration of terrestrial ecosystem models: a study of advanced Markov chain Monte Carlo methods

    Science.gov (United States)

    Lu, Dan; Ricciuto, Daniel; Walker, Anthony; Safta, Cosmin; Munger, William

    2017-09-01

    Calibration of terrestrial ecosystem models is important but challenging. Bayesian inference implemented by Markov chain Monte Carlo (MCMC) sampling provides a comprehensive framework to estimate model parameters and associated uncertainties using their posterior distributions. The effectiveness and efficiency of the method strongly depend on the MCMC algorithm used. In this work, a differential evolution adaptive Metropolis (DREAM) algorithm is used to estimate posterior distributions of 21 parameters for the data assimilation linked ecosystem carbon (DALEC) model using 14 years of daily net ecosystem exchange data collected at the Harvard Forest Environmental Measurement Site eddy-flux tower. The calibration of DREAM results in a better model fit and predictive performance compared to the popular adaptive Metropolis (AM) scheme. Moreover, DREAM indicates that two parameters controlling autumn phenology have multiple modes in their posterior distributions while AM only identifies one mode. The application suggests that DREAM is very suitable to calibrate complex terrestrial ecosystem models, where the uncertain parameter size is usually large and existence of local optima is always a concern. In addition, this effort justifies the assumptions of the error model used in Bayesian calibration according to the residual analysis. The result indicates that a heteroscedastic, correlated, Gaussian error model is appropriate for the problem, and the consequent constructed likelihood function can alleviate the underestimation of parameter uncertainty that is usually caused by using uncorrelated error models.

  19. Bayesian calibration of terrestrial ecosystem models: a study of advanced Markov chain Monte Carlo methods

    Directory of Open Access Journals (Sweden)

    D. Lu

    2017-09-01

    Full Text Available Calibration of terrestrial ecosystem models is important but challenging. Bayesian inference implemented by Markov chain Monte Carlo (MCMC sampling provides a comprehensive framework to estimate model parameters and associated uncertainties using their posterior distributions. The effectiveness and efficiency of the method strongly depend on the MCMC algorithm used. In this work, a differential evolution adaptive Metropolis (DREAM algorithm is used to estimate posterior distributions of 21 parameters for the data assimilation linked ecosystem carbon (DALEC model using 14 years of daily net ecosystem exchange data collected at the Harvard Forest Environmental Measurement Site eddy-flux tower. The calibration of DREAM results in a better model fit and predictive performance compared to the popular adaptive Metropolis (AM scheme. Moreover, DREAM indicates that two parameters controlling autumn phenology have multiple modes in their posterior distributions while AM only identifies one mode. The application suggests that DREAM is very suitable to calibrate complex terrestrial ecosystem models, where the uncertain parameter size is usually large and existence of local optima is always a concern. In addition, this effort justifies the assumptions of the error model used in Bayesian calibration according to the residual analysis. The result indicates that a heteroscedastic, correlated, Gaussian error model is appropriate for the problem, and the consequent constructed likelihood function can alleviate the underestimation of parameter uncertainty that is usually caused by using uncorrelated error models.

  20. Geomorphic processes affecting meadow ecosystems [chapter 3

    Science.gov (United States)

    Jerry R. Miller; Dru Germanoski; Mark L. Lord

    2011-01-01

    Three geomorphic processes are of primary concern with respect to the current and future state of wet meadow ecosystems: channel incision, avulsion (the abrupt movement of the channel to a new location on the valley floor), and gully formation. Gully formation often is accompanied by upvalley headcut migration and a phenomenon referred to as "groundwater sapping...

  1. Pressure and Buoyancy in Aquatic Ecosystems. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Cowan, Christina E.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module explores some of the characteristics of aquatic organisms which can be…

  2. Multiproxy evidence for terrestrial and aquatic ecosystem responses during the 8.2 ka cold event as recorded at Højby Sø, Denmark

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Rasmussen, Peter; Noe-Nygaard, Nanna

    2010-01-01

    A sediment succession from Højby Sø, a lake in eastern Denmark, covering the time period 9400–7400 cal yr BP was studied using high-resolution geochemistry, magnetic susceptibility, pollen, macrofossil, diatom, and algal pigment analysis to investigate responses of the terrestrial and aquatic...... ecosystems to the 8.2 ka cold event. A reduced pollen production by thermophilous deciduous tree taxa in the period c. 8250–8000 cal yr BP reveal that the forest ecosystem was affected by low temperatures during the summer and winter/early-spring seasons. This finding is consistent with the timing of the 8...... cal yr BP. Alteration of the terrestrial environment then resulted in a major aquatic ecosystem change with nutrient enrichment of the lake and enhanced productivity, which lasted until c. 7900 cal yr BP. Keywords: 8.2 ka cold event; Lake sediments; Palaeoclimate; Pollen; Macrofossils; Geochemistry...

  3. Can we predict groundwater discharge from terrestrial ecosystems using existing eco-hydrological concepts?

    Directory of Open Access Journals (Sweden)

    A. P. O'Grady

    2011-12-01

    Full Text Available There is increasing recognition of the role that groundwater plays in the maintenance of ecosystem structure and function. As a result, water resources planners need to develop an understanding of the water requirements for these ecosystems. In this study we reviewed estimates of groundwater discharge from terrestrial vegetation communities around Australia and explored this data set for empirical relationships that could be used to predict groundwater discharge in data poor areas. In particular we explored how leaf area index and the water balance of groundwater systems conformed to two existing ecohydrological frameworks; the Budyko framework, which describes the partitioning of rainfall into evapotranspiration and runoff within a simple supply and demand framework, and Eagleson's theory of ecological optimality. We demonstrate strong convergence with the predictions of both frameworks. Terrestrial groundwater systems discharging groundwater lie above the water limit line as defined in the Budyko framework. However, when climate wetness was recalculated to include groundwater discharge there was remarkable convergence of these sites along this water limit line. Thus, we found that there was a strong correlation between estimates of evapotranspiration derived from the Budyko's relationship with observed estimates of evapotranspiration. Similarly, the LAI of ecosystems with access to groundwater have higher LAI than those without access to groundwater, for a given climatic regime. However, again when discharge was included in the calculation of climate wetness index there was again strong convergence between the two systems, providing support for ecological optimality frameworks that maximize LAI under given water availability regimes. The simplicity and utility of these simple ecohydrological insights potentially provide a valuable tool for predicting groundwater discharge from terrestrial ecosystems, especially in data poor areas.

  4. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    Directory of Open Access Journals (Sweden)

    Javier Roales

    Full Text Available Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

  5. A review on the role of organic inputs in maintaining the soil carbon pool of the terrestrial ecosystem.

    Science.gov (United States)

    Bhattacharya, Satya Sundar; Kim, Ki-Hyun; Das, Subhasish; Uchimiya, Minori; Jeon, Byong Hun; Kwon, Eilhann; Szulejko, Jan E

    2016-02-01

    Among the numerous sources of greenhouse gases, emissions of CO2 are considerably affected by changes in the extent and type of land use, e.g., intensive agriculture, deforestation, urbanization, soil erosion, or wetland drainage. As a feasible option to control emissions from the terrestrial ecosystems, the scientific community has explored the possibility of enhancing soil carbon (C) storage capacity. Thus, restoration of damaged lands through conservation tillage, crop rotation, cover cropping, reforestation, sub-soiling of compacted lands, sustainable water management practices, and organic manuring are the major antidotes against attenuation of soil organic C (SOC) stocks. In this research, we focused on the effect of various man-made activities on soil biotic organics (e.g., green-, farm-yard manure, and composts) to understand how C fluxes from various sources contribute to the establishment of a new equilibrium in the terrestrial ecosystems. Although such inputs substitute a portion of chemical fertilizers, they all undergo activities that augment the rate and extent of decay to deplete the SOC bank. Here, we provide perspectives on the balancing factors that control the mineralization rate of organic matter. Our arguments are placed in the background of different land use types and their impacts on forests, agriculture, urbanization, soil erosion, and wetland destruction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Nitrogen and phosphorus limitation over long-term ecosystem development in terrestrial ecosystems.

    Directory of Open Access Journals (Sweden)

    Duncan N L Menge

    Full Text Available Nutrient limitation to net primary production (NPP displays a diversity of patterns as ecosystems develop over a range of timescales. For example, some ecosystems transition from N limitation on young soils to P limitation on geologically old soils, whereas others appear to remain N limited. Under what conditions should N limitation and P limitation prevail? When do transitions between N and P limitation occur? We analyzed transient dynamics of multiple timescales in an ecosystem model to investigate these questions. Post-disturbance dynamics in our model are controlled by a cascade of rates, from plant uptake (very fast to litter turnover (fast to plant mortality (intermediate to plant-unavailable nutrient loss (slow to weathering (very slow. Young ecosystems are N limited when symbiotic N fixation (SNF is constrained and P weathering inputs are high relative to atmospheric N deposition and plant N:P demand, but P limited under opposite conditions. In the absence of SNF, N limitation is likely to worsen through succession (decades to centuries because P is mineralized faster than N. Over long timescales (centuries and longer this preferential P mineralization increases the N:P ratio of soil organic matter, leading to greater losses of plant-unavailable N versus P relative to plant N:P demand. These loss dynamics favor N limitation on older soils despite the rising organic matter N:P ratio. However, weathering depletion favors P limitation on older soils when continual P inputs (e.g., dust deposition are low, so nutrient limitation at the terminal equilibrium depends on the balance of these input and loss effects. If NPP switches from N to P limitation over long time periods, the transition time depends most strongly on the P weathering rate. At all timescales SNF has the capacity to overcome N limitation, so nutrient limitation depends critically on limits to SNF.

  7. Black spots for aquatic and terrestrial ecosystems: impact of a perennial cormorant colony on the environment.

    Science.gov (United States)

    Klimaszyk, Piotr; Brzeg, Andrzej; Rzymski, Piotr; Piotrowicz, Ryszard

    2015-06-01

    The global growth of populations of different cormorant species has raised concern on the consequences of their presence in the environment. This study examined the impact of a perennial colony (160 breeding pairs) of great cormorants on terrestrial and aquatic ecosystems. The deposition of bird-originating nutrients within the area of colony, their accumulation in soils and the fluxed of chemical substances to a nearby lake were investigated. The impact of cormorants on terrestrial vegetation and microbial pollution of the lake were also studied. The soils beneath the colony were found to contain extremely high concentrations of nitrogen and phosphorus. The overgrowing vegetation was largely limited with nitrophilous and invasive species being more abundant. Increased loads of organic matter, nitrogen and phosphorus were also found in groundwater and particularly, surface runoff. The colony area delivered significant amounts of nutrients to the lake also when the birds were absent. The lake water near colony was also characterized by increased nutrient content and additionally higher number of faecal bacteria. The present results demonstrate the complexity through which the effect of cormorant colonies can be manifested simultaneously in terrestrial and aquatic ecosystem. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Net primary productivity of China's terrestrial ecosystems from a process model driven by remote sensing.

    Science.gov (United States)

    Feng, X; Liu, G; Chen, J M; Chen, M; Liu, J; Ju, W M; Sun, R; Zhou, W

    2007-11-01

    The terrestrial carbon cycle is one of the foci in global climate change research. Simulating net primary productivity (NPP) of terrestrial ecosystems is important for carbon cycle research. In this study, China's terrestrial NPP was simulated using the Boreal Ecosystem Productivity Simulator (BEPS), a carbon-water coupled process model based on remote sensing inputs. For these purposes, a national-wide database (including leaf area index, land cover, meteorology, vegetation and soil) at a 1 km resolution and a validation database were established. Using these databases and BEPS, daily maps of NPP for the entire China's landmass in 2001 were produced, and gross primary productivity (GPP) and autotrophic respiration (RA) were estimated. Using the simulated results, we explore temporal-spatial patterns of China's terrestrial NPP and the mechanisms of its responses to various environmental factors. The total NPP and mean NPP of China's landmass were 2.235 GtC and 235.2 gCm(-2)yr(-1), respectively; the total GPP and mean GPP were 4.418 GtC and 465 gCm(-2)yr(-1); and the total RA and mean RA were 2.227 GtC and 234 gCm(-2)yr(-1), respectively. On average, NPP was 50.6% of GPP. In addition, statistical analysis of NPP of different land cover types was conducted, and spatiotemporal patterns of NPP were investigated. The response of NPP to changes in some key factors such as LAI, precipitation, temperature, solar radiation, VPD and AWC are evaluated and discussed.

  9. The Stoichiometry of Nutrient Release by Terrestrial Herbivores and Its Ecosystem Consequences

    Directory of Open Access Journals (Sweden)

    Judith Sitters

    2017-04-01

    Full Text Available It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N and phosphorus (P recycled through herbivore release (i.e., waste N:P are mainly determined by the stoichiometric composition of the herbivore's food (food N:P and its body nutrient content (body N:P. Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C:N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

  10. The stoichiometry of nutrient release by terrestrial herbivores and its ecosystem consequences

    Science.gov (United States)

    Sitters, Judith; Bakker, Elisabeth S.; Veldhuis, Michiel P.; Veen, G. F.; Olde Venterink, Harry; Vanni, Michael J.

    2017-04-01

    It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N) and phosphorus (P) recycled through herbivore release (i.e., waste N:P) are mainly determined by the stoichiometric composition of the herbivore’s food (food N:P) and its body nutrient content (body N:P). Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C ):N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces) and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

  11. Terrestrial ecosystems, increased solar ultraviolet radiation, and interactions with other climate change factors.

    Science.gov (United States)

    Caldwell, M M; Bornman, J F; Ballaré, C L; Flint, S D; Kulandaivelu, G

    2007-03-01

    There have been significant advances in our understanding of the effects of UV-B radiation on terrestrial ecosystems, especially in the description of mechanisms of plant response. A further area of highly interesting research emphasizes the importance of indirect UV radiation effects on plants, pathogens, herbivores, soil microbes and ecosystem processes below the surface. Although photosynthesis of higher plants and mosses is seldom affected by enhanced or reduced UV-B radiation in most field studies, effects on growth and morphology (form) of higher plants and mosses are often manifested. This can lead to small reductions in shoot production and changes in the competitive balance of different species. Fungi and bacteria are generally more sensitive to damage by UV-B radiation than are higher plants. However, the species differ in their UV-B radiation sensitivity to damage, some being affected while others may be very tolerant. This can lead to changes in species composition of microbial communities with subsequent influences on processes such as litter decomposition. Changes in plant chemical composition are commonly reported due to UV-B manipulations (either enhancement or attenuation of UV-B in sunlight) and may lead to substantial reductions in consumption of plant tissues by insects. Although sunlight does not penetrate significantly into soils, the biomass and morphology of plant root systems of plants can be modified to a much greater degree than plant shoots. Root mass can exhibit sizeable declines with more UV-B. Also, UV-B-induced changes in soil microbial communities and biomass, as well as altered populations of small invertebrates have been reported and these changes have important implications for mineral nutrient cycling in the soil. Many new developments in understanding the underlying mechanisms mediating plant response to UV-B radiation have emerged. This new information is helpful in understanding common responses of plants to UV-B radiation

  12. The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

    DEFF Research Database (Denmark)

    Douglas, Thomas A.; Loseto, Lisa L.; MacDonald, Robie W.

    2012-01-01

    in wildlife are emphasised. We present discussions of the chemical transformations of newly deposited or transported Hg in marine, fresh water and terrestrial environments and of the movement of Hg from air, soil and water environmental compartments into food webs. Methylation, a key process controlling...... the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between...

  13. Disruption of the terrestrial plant ecosystem at the Cretaceous-Tertiary boundary, western interior

    Science.gov (United States)

    Tschudy, R.H.; Pillmore, C.L.; Orth, C.J.; Gilmore, J.S.; Knight, J.D.

    1984-01-01

    The palynologically defined Cretaceous-Tertiary boundary in the western interior of North America occurs at the top of an iridium-rich clay layer. The boundary is characterized by the abrupt disappearance of certain pollen species, immediately followed by a pronounced, geologically brief change in the ratio of fern spores to angiosperm pollen. The occurrence of these changes at two widely separated sites implies continentwide disruption of the terrestrial ecosystem, probably caused by a major catastrophic event at the end of the period.

  14. A lake classification concept for a more accurate global estimate of the dissolved inorganic carbon export from terrestrial ecosystems to inland waters.

    Science.gov (United States)

    Engel, Fabian; Farrell, Kaitlin J; McCullough, Ian M; Scordo, Facundo; Denfeld, Blaize A; Dugan, Hilary A; de Eyto, Elvira; Hanson, Paul C; McClure, Ryan P; Nõges, Peeter; Nõges, Tiina; Ryder, Elizabeth; Weathers, Kathleen C; Weyhenmeyer, Gesa A

    2018-03-26

    The magnitude of lateral dissolved inorganic carbon (DIC) export from terrestrial ecosystems to inland waters strongly influences the estimate of the global terrestrial carbon dioxide (CO 2 ) sink. At present, no reliable number of this export is available, and the few studies estimating the lateral DIC export assume that all lakes on Earth function similarly. However, lakes can function along a continuum from passive carbon transporters (passive open channels) to highly active carbon transformers with efficient in-lake CO 2 production and loss. We developed and applied a conceptual model to demonstrate how the assumed function of lakes in carbon cycling can affect calculations of the global lateral DIC export from terrestrial ecosystems to inland waters. Using global data on in-lake CO 2 production by mineralization as well as CO 2 loss by emission, primary production, and carbonate precipitation in lakes, we estimated that the global lateral DIC export can lie within the range of [Formula: see text] to [Formula: see text] Pg C yr -1 depending on the assumed function of lakes. Thus, the considered lake function has a large effect on the calculated lateral DIC export from terrestrial ecosystems to inland waters. We conclude that more robust estimates of CO 2 sinks and sources will require the classification of lakes into their predominant function. This functional lake classification concept becomes particularly important for the estimation of future CO 2 sinks and sources, since in-lake carbon transformation is predicted to be altered with climate change.

  15. [Factors influencing the variability in soil heterotrophic respiration from terrestrial ecosystem in China].

    Science.gov (United States)

    Xie, Wei; Chen, Shu-Tao; Hu, Zheng-Hua

    2014-01-01

    Soil heterotrophic respiration is one of the key factors for estimating ecosystem carbon balance. Measurement data of soil heterotrophic respiration from terrestrial ecosystem in China were collected. Climate data (annual precipitation and annual mean air temperature) and relevant environmental factors (e. g. tree age) were also collected. Results indicated that the relationship between heterotrophic respiration and soil respiration could be explained by a power function. Heterotrophic respiration increased with the increase of soil respiration. The power function explained 73% of the variability (R2 = 0.730, P power function could be used to explain the relationship between the ratio of heterotrophic respiration to soil respiration and tree age. Further investigation showed that the relationship between measured annual heterotrophic respiration and modeled heterotrophic respiration by using an empirical model could be described by a linear function, indicating that the empirical model well fitted the variability in heterotrophic respiration.

  16. Mercury Exposure Affects the Reproductive Success of a Free-living Terrestrial Songbird, the Carolina Wren, (Thryothrus ludovicianus)

    Science.gov (United States)

    The impacts of mercury contamination on aquatic-feeding wildlife are well-established, but recent attention has focused on the effects of mercury on species in terrestrial ecosystems. Despite mounting evidence of mercury accumulation in terrestrial ecosystems, there is little dat...

  17. Transfer parameters for ICRP's Reference Animals and Plants in a terrestrial Mediterranean ecosystem.

    Science.gov (United States)

    Guillén, J; Beresford, N A; Baeza, A; Izquierdo, M; Wood, M D; Salas, A; Muñoz-Serrano, A; Corrales-Vázquez, J M; Muñoz-Muñoz, J G

    2018-06-01

    A system for the radiological protection of the environment (or wildlife) based on Reference Animals and Plants (RAPs) has been suggested by the International Commission on Radiological Protection (ICRP). To assess whole-body activity concentrations for RAPs and the resultant internal dose rates, transfer parameters are required. However, transfer values specifically for the taxonomic families defined for the RAPs are often sparse and furthermore can be extremely site dependent. There is also a considerable geographical bias within available transfer data, with few data for Mediterranean ecosystems. In the present work, stable element concentrations (I, Li, Be, B, Na, Mg, Al, P, S, K. Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Cs, Ba, Tl, Pb and U) in terrestrial RAPs, and the corresponding whole-body concentration ratios, CR wo , were determined in two different Mediterranean ecosystems: a Pinewood and a Dehesa (grassland with disperse tree cover). The RAPs considered in the Pinewood ecosystem were Pine Tree and Wild Grass; whereas in the Dehesa ecosystem those considered were Deer, Rat, Earthworm, Bee, Frog, Duck and Wild Grass. The CR wo values estimated from these data are compared to those reported in international compilations and databases. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Characteristics of terrestrial and aquatic ecosystems of two locations in Deaf Smith and Swisher Counties, Texas

    International Nuclear Information System (INIS)

    1984-11-01

    According to the Civilian Radioactive Waste Management Program and the Nuclear Waste Policy Act of 1982 (P.L. 97-425), a potential nuclear waste repository site must be chosen with consideration of potential impacts on terrestrial and aquatic ecosystems. This report is a preliminary environmental characterization of two locations in the Texas Panhandle, one in Deaf Smith County and the other in Swisher County, that have been recommended for further study. A description of important natural areas is offered as a basis for comparative studies of the two locations and for the identification and screening of potential repository sites. Information on current land uses, potential habitats, and expected plant and wildlife species is provided to assist field investigators in the collection of baseline data in support of further siting activities. The results of limited field surveys are also included. The report is in two parts. Part I contains a characterization of terrestrial ecological resources based upon limited field surveys aimed at verifying the presence of plant communities and wildlife habitats. It also presents inventories of species with special status, species with recreational and economic importance, and species of ecological value to important or special-status species. Part II presents information on aquatic ecosystems and resources derived primarily from a review of the literature, interviews, and limited field surveys. 21 figures, 18 tables

  19. Soil nitric oxide emissions from terrestrial ecosystems in China: a synthesis of modeling and measurements

    Science.gov (United States)

    Huang, Yong; Li, Dejun

    2014-01-01

    Soils are among the major sources of atmospheric nitric oxide (NO), which play a crucial role in atmospheric chemistry. Here we systematically synthesized the modeling studies and field measurements and presented a novel soil NO emission inventory of terrestrial ecosystems in China. The previously modeled inventories ranged from 480 to 1375 and from 242.8 to 550 Gg N yr−1 for all lands and croplands, respectively. Nevertheless, all the previous modeling studies were conducted based on very few measurements from China. According to the current synthesis of field measurements, most soil NO emission measurements were conducted at croplands, while the measurements were only conducted at two sites for forest and grassland. The median NO flux was 3.2 ng N m−2 s−1 with a fertilizer induced emission factor (FIE) of 0.04% for rice fields, and was 7.1 ng N m−2 s−1 with an FIE of 0.67% for uplands. A novel NO emission inventory of 1226.33 (ranging from 588.24 to 2132.05) Gg N yr−1 was estimated for China's terrestrial ecosystems, which was about 18% of anthropogenic emissions. More field measurements should be conducted to cover more biomes and obtain more representative data in order to well constrain soil NO emission inventory of China. PMID:25490942

  20. The greenhouse gas balance of Italy. An insight on managed and natural terrestrial ecosystems

    International Nuclear Information System (INIS)

    Valentini, Riccardo; Miglietta, Franco

    2015-01-01

    Comprehensively addresses the full greenhouse gases budget of the Italian landscape. Presents the results of the national project CARBOITALY. Provides new data and analyses in the framework of climate policies. The book addresses in a comprehensive way the full greenhouse gases budget of the Italian landscape, focusing on land use and terrestrial ecosystems. In recent years there has been a growing interest in the role of terrestrial ecosystems with regard to the carbon cycle and only recently a regional approach has been considered for its specificity in terms of new methodologies for observations and models and its relevance for national policies on mitigation and adaptation to climate changes. In terms of methods this book describes the role of flux networks and data-driven models, airborne regional measurements of fluxes and specific sectoral approaches related to important components of the human and natural landscapes. There is also a growing need on the part of institutions, agencies and policy stakeholders for new data and analyses enabling them to improve their national inventories of greenhouse gases and their compliance with the UNFCCC process. In this respect the data presented is a basis for a full carbon accounting and available to relevant stakeholders for improvements and/or verification of national inventories. The wealth of research information is the result of a national project, CARBOITALY, which involved 15 Italian institutions and several researchers to provide new data and analyses in the framework of climate policies.

  1. Geophysical Evidence to Link Terrestrial Insect Diversity and Groundwater Availability in Non-Riparian Ecosystems

    Science.gov (United States)

    Pehringer, M.; Carr, G.; Long, H.; Parsekian, A.

    2015-12-01

    Wyoming, the third driest state in the United States, is home to a high level of biodiversity. In many cases, ecosystems are dependent on the vast systems of water resting just below the surface. This groundwater supports a variety of organisms that live far from surface water and its surrounding riparian zone, where more than 70% of species reside. In order to observe the correlation of groundwater presence and biodiversity in non-riparian ecosystems, a study was conducted to look specifically at terrestrial insect species linked to groundwater in Bighorn National Forest, WY. It was hypothesized that the more groundwater present, the greater the diversity of insects would be. Sample areas were randomly selected in non-riparian zones and groundwater was evaluated using a transient electromagnetic (TEM) geophysical instrument. Electrical pulses were transmitted through a 40m by 40m square of wire to measure levels of resistivity from near the surface to several hundred meters below ground. Pulses are echoed back to the surface and received by a smaller 10m by 10m square of wire, and an even smaller 1m by 1m square of wire set inside the larger transmitting wire. An insect population and species count was then conducted within the perimeter set by the outer transmitting wire. The results were not as hypothesized. More inferred groundwater below the surface resulted in a smaller diversity of species. Inversely, the areas with a smaller diversity held a larger total population of terrestrial insects.

  2. Biological nitrogen fixation: rates, patterns and ecological controls in terrestrial ecosystems

    Science.gov (United States)

    Vitousek, Peter M.; Menge, Duncan N.L.; Reed, Sasha C.; Cleveland, Cory C.

    2013-01-01

    New techniques have identified a wide range of organisms with the capacity to carry out biological nitrogen fixation (BNF)—greatly expanding our appreciation of the diversity and ubiquity of N fixers—but our understanding of the rates and controls of BNF at ecosystem and global scales has not advanced at the same pace. Nevertheless, determining rates and controls of BNF is crucial to placing anthropogenic changes to the N cycle in context, and to understanding, predicting and managing many aspects of global environmental change. Here, we estimate terrestrial BNF for a pre-industrial world by combining information on N fluxes with 15N relative abundance data for terrestrial ecosystems. Our estimate is that pre-industrial N fixation was 58 (range of 40–100) Tg N fixed yr−1; adding conservative assumptions for geological N reduces our best estimate to 44 Tg N yr−1. This approach yields substantially lower estimates than most recent calculations; it suggests that the magnitude of human alternation of the N cycle is substantially larger than has been assumed.

  3. The response of terrestrial ecosystems to climate variability associated with the North Atlantic Oscillation

    Science.gov (United States)

    Mysterud, Alte; Stenseth, Nils Chr.; Yoccoz, Nigel G.; Ottersen, Geir; Langvatn, Rolf

    Climatic factors influence a variety of ecological processes determining patterns of species density and distribution in a wide range of terrestrial ecosystems. We review the effects of the NAO on processes and patterns of terrestrial ecosystems, including both plants and animals. In plants, the NAO index correlates with date of first flowering, tree ring growth and with quality of agricultural crops (wheat and wine grapes). Also, breeding dates are earlier after high NAO index winters for amphibians and birds in Europe. Population dynamical consequences of the NAO have also been reported for birds, and the differential impact of the NAO on two similar species may prevent competitive exclusion. Different effects of the NAO on large herbivore populations have been reported for different regions, depending on limiting factors and the correlation with local weather parameters. The NAO synchronizes population dynamics of lynx and some other carnivore populations in the eastern U.S. Most effects are on an ecological time scale; the evolutionary consequences of long term trends in the NAO are poorly documented. Important for predator and prey dynamics is (1) the disruption of phenology (the match-mismatch hypothesis), (2) that there may be delayed effects (cohort-effects), and (3) that effects of the NAO may interact with other factors such as density. We discuss the challenges related to nonlinearity, of using different climate indices, and how we can progress using these pattern-oriented NAO studies at coarse scales to conduct better process-oriented small-scale experiments.

  4. Leveraging atmospheric CO2 observations to constrain the climate sensitivity of terrestrial ecosystems

    Science.gov (United States)

    Keppel-Aleks, G.

    2015-12-01

    A significant challenge in understanding, and therefore modeling, the response of terrestrial carbon cycling to climate and environmental drivers is that vegetation varies on spatial scales of order a few kilometers whereas Earth system models (ESMs) are run with characteristic length scales of order 100 km. Atmospheric CO2 provides a constraint on carbon fluxes at spatial scales compatible with the resolution of ESMs due to the fact that atmospheric mixing renders a single site representative of fluxes within a large spatial footprint. The variations in atmospheric CO2 at both seasonal and interannual timescales largely reflect terrestrial influence. I discuss the use of atmospheric CO2 observations to benchmark model carbon fluxes over a range of spatial scales. I also discuss how simple models can be used to test functional relationships between the CO2 growth rate and climate variations. In particular, I show how atmospheric CO2 provides constraints on ecosystem sensitivity to climate drivers in the tropics, where tropical forests and semi-arid ecosystems are thought to account for much of the variability in the contemporary carbon sink.

  5. Inter-annual variabilities in biogeophysical feedback of terrestrial ecosystem to atmosphere using a land surface model

    Science.gov (United States)

    Seo, C.; Hong, S.; Jeong, H. M.; Jeon, J.

    2017-12-01

    Biogeophysical processes of terrestrial ecosystem such as water vapor and energy flux are the key features to understand ecological feedback to atmospheric processes and thus role of terrestrial ecosystem in climate system. For example, it has been recently known that the ecological feedback through water vapor and energy flux results in regulating regional weathers and climates which is one of the fundamental functions of terrestrial ecosystem. In regional scale, water vapor flux has been known to give negative feedback to atmospheric warming, while energy flux from the surface has been known to positive feedback. In this study, we explored the inter-annual variabilities in these two biogeophysical features to see how the climate regulating functions of terrestrial ecosystem have been changed with climate change. We selected a land surface model involving vegetation dynamics that is forced by atmospheric data from NASA including precipitation, temperature, wind, surface pressure, humidity, and incoming radiations. From the land surface model, we simulated 60-year water vapor and energy fluxes from 1961 to 2010, and calculates feedbacks of terrestrial ecosystem as in radiation amount into atmosphere. Then, we analyzed the inter-annual variabilities in the feedbacks. The results showed that some mid-latitude areas showing very high variabilities in precipitation showed higher positive feedback and/or lower negative feedback. These results suggest deterioration of the biogeophyisical factor of climate regulating function over those regions.

  6. Rainfall changes affect the algae dominance in tank bromeliad ecosystems

    Science.gov (United States)

    Pires, Aliny Patricia Flauzino; Leal, Juliana da Silva; Peeters, Edwin T. H. M.

    2017-01-01

    Climate change and biodiversity loss have been reported as major disturbances in the biosphere which can trigger changes in the structure and functioning of natural ecosystems. Nonetheless, empirical studies demonstrating how both factors interact to affect shifts in aquatic ecosystems are still unexplored. Here, we experimentally test how changes in rainfall distribution and litter diversity affect the occurrence of the algae-dominated condition in tank bromeliad ecosystems. Tank bromeliads are miniature aquatic ecosystems shaped by the rainwater and allochthonous detritus accumulated in the bases of their leaves. Here, we demonstrated that changes in the rainfall distribution were able to reduce the chlorophyll-a concentration in the water of bromeliad tanks affecting significantly the occurrence of algae-dominated conditions. On the other hand, litter diversity did not affect the algae dominance irrespective to the rainfall scenario. We suggest that rainfall changes may compromise important self-reinforcing mechanisms responsible for maintaining high levels of algae on tank bromeliads ecosystems. We summarized these results into a theoretical model which suggests that tank bromeliads may show two different regimes, determined by the bromeliad ability in taking up nutrients from the water and by the total amount of light entering the tank. We concluded that predicted climate changes might promote regime shifts in tropical aquatic ecosystems by shaping their structure and the relative importance of other regulating factors. PMID:28422988

  7. The importance of plant genotype and contemporary evolution for terrestrial ecosystem processes.

    Science.gov (United States)

    Fitzpatrick, Connor R; Agrawal, Anurag A; Basiliko, Nathan; Hastings, Amy P; Isaac, Marney E; Preston, Michael; Johnson, Marc T J

    2015-10-01

    Plant genetic variation and evolutionary dynamics are predicted to impact ecosystem processes but these effects are poorly understood. Here we test the hypothesis that plant genotype and contemporary evolution influence the flux of energy and nutrients through soil, which then feedback to affect seedling performance in subsequent generations. We conducted a multiyear field evolution experiment using the native biennial plant Oenothera biennis. This experiment was coupled with experimental assays to address our hypothesis and quantify the relative importance of evolutionary and ecological factors on multiple ecosystem processes. Plant genotype, contemporary evolution, spatial variation, and herbivory affected ecosystem processes (e.g., leaf decay, soil respiration, seedling performance, N cycling), but their relative importance varied between specific ecosystem variables. Insect herbivory and evolution also contributed to a feedback that affected seedling biomass of O. biennis in the next generation. Our results show that heritable variation among plant genotypes can be an important factor affecting local ecosystem processes, and while effects of contemporary evolution were detectable and sometimes strong, they were often contingent on other ecological, factors.

  8. Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic.

    Science.gov (United States)

    MacMillan, Gwyneth Anne; Chételat, John; Heath, Joel P; Mickpegak, Raymond; Amyot, Marc

    2017-10-18

    Few ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environmental impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. To understand how REEs behave in remote northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂ 15 N, ∂ 13 C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N = 339). Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REEs generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low total REE levels in muscle tissue (∑REE for 15 elements <0.1 nmol g -1 ), yet accumulation was an order of magnitude higher in liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-specific, with limited potential for biomagnification. This study provides novel data on the behaviour of REEs in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

  9. Biogenic and non-biogenic Si pools in terrestrial ecosystems: results from a novel analysis method

    Science.gov (United States)

    Barao, Lucia; Vandevenne, Floor; Clymans, Wim; Meire, Patrick; Frings, Patrick; Conley, Daniel; Struyf, Eric

    2015-04-01

    Silicon (Si) is a chemical element frequently associated with highly abundant silicate minerals in the Earth crust. Over millions of years, the interaction of such minerals with the atmosphere and hydrosphere produces a myriad of processed compounds, and the mineral weathering consumes CO2 during the process. The weathering of minerals also triggers the export of dissolved Si (DSi) to coastal waters and the ocean. Here, DSi is deposited in diatom frustules, in an amorphous biogenic form (BSi). Diatoms account for 50% of the primary production and are crucial for the export of carbon into the deep sea. In recent years, it was acknowledged that terrestrial systems filter the Si transition from the terrestrial mineral to the marine and coastal biological pool, by the incorporation of DSi into plants. In this process, DSi is taken up by roots together with other nutrients and precipitates in plant cells in amorphous structures named phytoliths. After dead, plant tissues become mixed in the top soil, where BSi is available for dissolution and will control the DSi availability in short time scales. Additionally, Si originated from soil forming processes can also significantly interfere with the global cycle. The Si cycle in terrestrial ecosystems is a key factor to coastal ecology, plant ecology, biogeochemistry and agro-sciences, but the high variability of different biogenic and non-biogenic Si pools remains as an obstacle to obtain accurate measurements. The traditional methods, developed to isolate diatoms in ocean sediments, only account for simple mineral corrections. In this dissertation we have adapted a novel continuous analysis method (during alkaline extraction) that uses Si-Al ratios and reactivity to differ biogenic from non-biogenic fractions. The method was originally used in marine sediments, but we have developed it to be applicable in a wide range of terrestrial, aquatic and coastal ecosystems. We first focused on soils under strong human impact in

  10. The terminal Paleozoic fungal event: evidence of terrestrial ecosystem destabilization and collapse.

    Science.gov (United States)

    Visscher, H; Brinkhuis, H; Dilcher, D L; Elsik, W C; Eshet, Y; Looy, C V; Rampino, M R; Traverse, A

    1996-03-05

    Because of its prominent role in global biomass storage, land vegetation is the most obvious biota to be investigated for records of dramatic ecologic crisis in Earth history. There is accumulating evidence that, throughout the world, sedimentary organic matter preserved in latest Permian deposits is characterized by unparalleled abundances of fungal remains, irrespective of depositional environment (marine, lacustrine, fluviatile), floral provinciality, and climatic zonation. This fungal event can be considered to reflect excessive dieback of arboreous vegetation, effecting destabilization and subsequent collapse of terrestrial ecosystems with concomitant loss of standing biomass. Such a scenario is in harmony with predictions that the Permian-Triassic ecologic crisis was triggered by the effects of severe changes in atmospheric chemistry arising from the rapid eruption of the Siberian Traps flood basalts.

  11. Recent Changes in Global Photosynthesis and Terrestrial Ecosystem Respiration Constrained From Multiple Observations

    Science.gov (United States)

    Li, Wei; Ciais, Philippe; Wang, Yilong; Yin, Yi; Peng, Shushi; Zhu, Zaichun; Bastos, Ana; Yue, Chao; Ballantyne, Ashley P.; Broquet, Grégoire; Canadell, Josep G.; Cescatti, Alessandro; Chen, Chi; Cooper, Leila; Friedlingstein, Pierre; Le Quéré, Corinne; Myneni, Ranga B.; Piao, Shilong

    2018-01-01

    To assess global carbon cycle variability, we decompose the net land carbon sink into the sum of gross primary productivity (GPP), terrestrial ecosystem respiration (TER), and fire emissions and apply a Bayesian framework to constrain these fluxes between 1980 and 2014. The constrained GPP and TER fluxes show an increasing trend of only half of the prior trend simulated by models. From the optimization, we infer that TER increased in parallel with GPP from 1980 to 1990, but then stalled during the cooler periods, in 1990-1994 coincident with the Pinatubo eruption, and during the recent warming hiatus period. After each of these TER stalling periods, TER is found to increase faster than GPP, explaining a relative reduction of the net land sink. These results shed light on decadal variations of GPP and TER and suggest that they exhibit different responses to temperature anomalies over the last 35 years.

  12. Unmanned Aircraft Systems Used over Western U.S. Rangelands to Characterize Terrestrial Ecosystems

    Science.gov (United States)

    Rango, A.

    2015-12-01

    New remote sensing methods to quantify terrestrial ecosystems have developed rapidly over the past 10 years. New platforms with improved aeronautical capabilities have become known as Unmanned Aircraft Systems (UAS). In addition to the new aircraft, sensors are becoming smaller and some can fit into limited payload bays. The miniaturization process is well underway, but much remains to be done. Rather than using a wide variety of sensors, a limited number of instruments is recommended. At the moment we fly 2-3 instruments (digital SLR camera, 6-band multispectral camera, and single video camera). Our flights are primarily over low population density western U.S. rangeland with objectives to assess rangeland health, active erosion, vegetation change, phenology, livestock movement, and vegetation type consumed by grazing animals. All of our UAS flights are made using a serpentine flight path with overlapping images at an altitude of 700 ft (215 m). This altitude allows hyperspatial imagery with a resolution of 5-15 cm depending upon the sensor being used, and it allows determination of vegetation type based on the plant structure and vegetation geometries, or by multispectral analysis. In addition to advances in aircraft and sensor technology, image processing software has become more sophisticated. Future development is necessary, and we can expect improvement in sensors, aircraft, data collection, and application to terrestrial ecosystems. Of 17 ARS research laboratories across the country four laboratories are interested in future UAS applications and another 13 already have at least one UAS. In 2015 the Federal Aviation Administration proposed a framework of recommendations that would allow routine use of certain small UAS (those weighing less than 55 lb (25 kg)). Although these new regulations will provide increased flexibility in how flights are made, other operations will still require the use of a Certificate of Authorization.

  13. Chitinolytic and pectinolytic community of soils and terrestrial ecosystems of different climatic zones

    Science.gov (United States)

    Lukacheva, Evgeniya; Manucharova, Natalia

    2014-05-01

    Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. The breakdown of chitin and pectin was studied. The aim was to provide a characterization of microorganisms involved in chitin and pectin degradation in the soils and terrestrial ecosystems in different climatic zones: steppe zone, deciduous forests and taiga. Samples of leaves, soils and litter were studied and compared. Quantity of eukaryote and procaryote organisms increased in samples with chitin and pectin comparing with control samples. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic technique developed that is used to detect and localize the presence or absence of specific DNA sequences on chromosomes. Quantity of Actinomycets and Firmicures was the largest among identified cells with metabolic activity in both types of the samples. Should be noted significant increasing of the quantity of Acidobateria and Bacteroidetes in pectinolytic community and Alphaproteobacteria in chitinolytic community soils. The difference between climatic zones was studied and the mathematical model was created. The mathematic model could be use in different aims, such as prognosis of microbial community composition and their classification.

  14. Green Ocean Amazon 2014/15 Terrestrial Ecosystem Project (Geco) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, Kolby [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-06-01

    In conjunction with the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility GoAmazon campaign, the Terrestrial Ecosystem Science (TES)-funded Green Ocean Amazon (GoAmazon 2014/15) terrestrial ecosystem project (Geco) was designed to: • evaluate the strengths and weaknesses of leaf-level algorithms for biogenic volatile organic compounds (BVOCs) emissions in Amazon forests near Manaus, Brazil, and • conduct mechanistic field studies to characterize biochemical and physiological processes governing leaf- and landscape-scale tropical forest BVOC emissions, and the influence of environmental drivers that are expected to change with a warming climate. Through a close interaction between modeling and observational activities, including the training of MS and PhD graduate students, post-doctoral students, and technicians at the National Institute for Amazon Research (INPA), the study aimed at improving the representation of BVOC-mediated biosphere-atmosphere interactions and feedbacks under a warming climate. BVOCs can form cloud condensation nuclei (CCN) that influence precipitation dynamics and modify the quality of down welling radiation for photosynthesis. However, our ability to represent these coupled biosphere-atmosphere processes in Earth system models suffers from poor understanding of the functions, identities, quantities, and seasonal patterns of BVOC emissions from tropical forests as well as their biological and environmental controls. The Model of Emissions of Gases and Aerosols from Nature (MEGAN), the current BVOC sub-model of the Community Earth System Model (CESM), was evaluated to explore mechanistic controls over BVOC emissions. Based on that analysis, a combination of observations and experiments were studied in forests near Manaus, Brazil, to test existing parameterizations and algorithm structures in MEGAN. The model was actively modified as needed to improve tropical BVOC emission simulations on

  15. Exploring New Multi-Instrument Approaches To Observing Terrestrial Ecosystems And The Carbon Cycle From Space

    Science.gov (United States)

    Pavlick, R.; Schimel, D.; Dubayah, R.; Wennberg, P. O.

    2015-12-01

    In October 2015, we held a five-day workshop at the Keck Institute for Space Studies, bringing together experts on terrestrial ecology and the carbon cycle, remote sensing, in-situ networks, modeling, and systems engineering. The goals of the workshop were to: 1) Identify grand challenges in terrestrial ecology and carbon cycle science and outline how new multi-instrument remote sensing products can enable revolutionary advancements towards unlocking those challenges 2) Collaborate on using existing airborne, space-based, and ground-based measurements to highlight and quantify those potential advancements 3) Explore how multi-instrument data products can reduce key parameter and structural uncertainties in terrestrial biosphere models The more general themes of the workshop were framed around the potential, that in a few years time, we could see co-flight of suite of sensors aboard the International Space Station providing simultaneous observations of ecosystem structure, functioning, and composition. These include two instruments recently selected by the NASA Earth Venture Instrument program, GEDI, a LiDAR which will measure the 3D structure and biomass of forests, and ECOSTRESS, a thermal radiometer, which will estimate evapotranspiration and plant water stress. These also include two proposed instruments, OCO-3, capable of targeted mapping of solar-induced fluorescence and column CO2, and an imaging spectrometer, which would provide near-global maps of plant biodiversity and plant canopy biochemistry. The workshop sought to break down the 'stovepiping', that can arise from the traditionally contingency-adverse systems engineering approach to mission planning, by developing a broader strategy that would combine data products from multiple sensors to address carbon cycle grand challenge questions that no single sensor can address alone. We will present highlights from the workshop, as well as results from the discussion of observation needs, potential data

  16. Collateral damage to marine and terrestrial ecosystems from Yankee whaling in the 19th century.

    Science.gov (United States)

    Drew, Joshua; López, Elora H; Gill, Lucy; McKeon, Mallory; Miller, Nathan; Steinberg, Madeline; Shen, Christa; McClenachan, Loren

    2016-11-01

    Yankee whalers of the 19th century had major impacts on populations of large whales, but these leviathans were not the only taxa targeted. Here, we describe the "collateral damage," the opportunistic or targeted taking of nongreat whale species by the American whaling industry. Using data from 5,064 records from 79 whaling logs occurring between 1840 and 1901, we show that Yankee whalers captured 5,255 animals across three large ocean basins from 32 different taxonomic categories, including a wide range of marine and terrestrial species. The taxa with the greatest number of individuals captured were walruses ( Odobenus rosmarus ), ducks (family Anatidae), and cod ( Gadus sp.). By biomass, the most captured species were walruses, grampus (a poorly defined group within Odontoceti), and seals (family Otariidae). The whalers captured over 2.4 million kg of nongreat whale meat equaling approximately 34 kg of meat per ship per day at sea. The species and areas targeted shifted over time in response to overexploitation of whale populations, with likely intensive local impacts on terrestrial species associated with multiyear whaling camps. Our results show that the ecosystem impacts of whaling reverberated on both marine and coastal environments.

  17. Direct and indirect effects of climatic variations on the interannual variability in net ecosystem exchange across terrestrial ecosystems

    Directory of Open Access Journals (Sweden)

    Junjiong Shao

    2016-08-01

    Full Text Available Climatic variables not only directly affect the interannual variability (IAV in net ecosystem exchange of CO2 (NEE but also indirectly drive it by changing the physiological parameters. Identifying these direct and indirect paths can reveal the underlying mechanisms of carbon (C dynamics. In this study, we applied a path analysis using flux data from 65 sites to quantify the direct and indirect climatic effects on IAV in NEE and to evaluate the potential relationships among the climatic variables and physiological parameters that represent physiology and phenology of ecosystems. We found that the maximum photosynthetic rate was the most important factor for the IAV in gross primary productivity (GPP, which was mainly induced by the variation in vapour pressure deficit. For ecosystem respiration (RE, the most important drivers were GPP and the reference respiratory rate. The biome type regulated the direct and indirect paths, with distinctive differences between forests and non-forests, evergreen needleleaf forests and deciduous broadleaf forests, and between grasslands and croplands. Different paths were also found among wet, moist and dry ecosystems. However, the climatic variables can only partly explain the IAV in physiological parameters, suggesting that the latter may also result from other biotic and disturbance factors. In addition, the climatic variables related to NEE were not necessarily the same as those related to GPP and RE, indicating the emerging difficulty encountered when studying the IAV in NEE. Overall, our results highlight the contribution of certain physiological parameters to the IAV in C fluxes and the importance of biome type and multi-year water conditions, which should receive more attention in future experimental and modelling research.

  18. Deriving Vegetation Dynamics of Natural Terrestrial Ecosystems from MODIS NDVI/EVI Data over Turkey.

    Science.gov (United States)

    Evrendilek, Fatih; Gulbeyaz, Onder

    2008-09-01

    The 16-day composite MODIS vegetation indices (VIs) at 500-m resolution for the period between 2000 to 2007 were seasonally averaged on the basis of the estimated distribution of 16 potential natural terrestrial ecosystems (NTEs) across Turkey. Graphical and statistical analyses of the time-series VIs for the NTEs spatially disaggregated in terms of biogeoclimate zones and land cover types included descriptive statistics, correlations, discrete Fourier transform (DFT), time-series decomposition, and simple linear regression (SLR) models. Our spatio-temporal analyses revealed that both MODIS VIs, on average, depicted similar seasonal variations for the NTEs, with the NDVI values having higher mean and SD values. The seasonal VIs were most correlated in decreasing order for: barren/sparsely vegetated land > grassland > shrubland/woodland > forest; (sub)nival > warm temperate > alpine > cool temperate > boreal = Mediterranean; and summer > spring > autumn > winter. Most pronounced differences between the MODIS VI responses over Turkey occurred in boreal and Mediterranean climate zones and forests, and in winter (the senescence phase of the growing season). Our results showed the potential of the time-series MODIS VI datasets in the estimation and monitoring of seasonal and interannual ecosystem dynamics over Turkey that needs to be further improved and refined through systematic and extensive field measurements and validations across various biomes.

  19. The behavior of 89Sr and tritium water (HTO) in a model terrestrial-aquatic ecosystem

    International Nuclear Information System (INIS)

    Zhang Yongxi; Wang Shouxiang; Chen Chuangqun; Sun Zhiming; Huang Dan; Hu Bingmin

    1993-08-01

    The effect of land polluted by 89 Sr on water body and the immigration of HTO from water body to land were studied in a modelling terrestrial-aquatic ecosystem. The results are as follows: (1) The 89 Sr in soil quickly migrated to common bean plants and its concentration in common bean plants was increasing with the time, but the concentration of 89 Sr in soil was exponentially declining with the depth. About 5% of 89 Sr was migrated to water body by rainfall then distributed to other components, and it can be concentrated by aquatics in a certain degree. (2) when HTO entered into the water body, it would migrate to other components of the ecosystem. and the HTO in the pool was linearly decreasing with the time. However, the concentration of HTO in the sediments and aquatics would firstly increase then reached the peak and went down. The tritium of HTO was existed in two forms in the sediments and aquatics, free water (HTO) and bound tritium. HTO was also migrated to the adjacent land soil and absorbed by land crop plants, within one and half months the land system contained 24% of the total tritium in the aquatic system

  20. Ground-based grasslands data to support remote sensing and ecosystem modeling of terrestrial primary production

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.J.; Turner, R.S. [Oak Ridge National Lab., TN (United States); Scurlock, J.M.O. [King`s College London, (England); Jennings, S.V. [Tennessee Univ., Knoxville, TN (United States)

    1995-12-31

    Estimating terrestrial net primary production (NPP) using remote- sensing tools and ecosystem models requires adequate ground-based measurements for calibration, parameterization, and validation. These data needs were strongly endorsed at a recent meeting of ecosystem modelers organized by the International Geosphere-Biosphere Programme`s (IGBP`s) Data and Information System (DIS) and its Global Analysis, Interpretation, and Modelling (GAIM) Task Force. To meet these needs, a multinational, multiagency project is being coordinated by the IGBP DIS to compile existing NPP data from field sites and to regionalize NPP point estimates to various-sized grid cells. Progress at Oak Ridge National Laboratory (ORNL) on compiling NPP data for grasslands as part of the IGBP DIS data initiative is described. Site data and associated documentation from diverse field studies are being acquired for selected grasslands and are being reviewed for completeness, consistency, and adequacy of documentation, including a description of sampling methods. Data are being compiled in a database with spatial, temporal, and thematic characteristics relevant to remote sensing and global modeling. NPP data are available from the ORNL Distributed Active Archive Center (DAAC) for biogeochemical dynamics. The ORNL DAAC is part of the Earth Observing System Data and Information System, of the US National Aeronautics and Space Administration.

  1. Proceedings of the international workshop on the effects of acid precipitation on vegetation, soils, and terrestrial ecosystems, Brookhaven National Laboratory, June 12 to 14, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S.; Hendrey, G.R. (eds.)

    1979-01-01

    The objectives of the workshop were to determine the levels of current knowledge of the effects of acid precipitation on vegetation, soils, and terrestrial ecosystems; research needed in these areas to understand the environmental impacts of acid rain; and to help coordinate research groups to avoid excessive duplication of research. The workshop was designed so that researchers in the areas of effects of acid precipitation on vegetation, soils, and whole ecosystem approaches could communicate effectively. There was a general consensus that acid rain at extreme ambient levels, or in artificial systems that simulate extreme ambient levels, causes injury to plant tissues. A major area of concern of acid rain injury was thought to be plant reproduction. The overall levels of significance of plant injury among various plant species remain unknown. The most important priorities in the area of effects of acid rain on crops were an evaluation of effects on crop yields and interaction of acid rain in combination with pollutants on various plants. Few participants thought that ambient acid rain loadings have altered soils to such a degree that plants are affected at present, but many thought that acid rain could cause some alterations in soils. The most important research priorities were in the areas of the effects of acid rain on increased leaching of exchangeable plant nutrients and alterations in phosphorous availability. All participants agreed that there are alterations in terrestrial ecosystems from acid precipitation. However, no demonstrated harmful effects were presented from natural ecosystems. Further research on the effects of acid rain on terrestrial ecosystems should be directed mostly toward the interaction of acid rain with toxic elements such as Al, Fe, and Mn and on the effects on nutrient cycling, especially that of nitrogen.

  2. Radioactive characterization of the terrestrial ecosystem in the area of location of the Juragua Nuclear Power Plant

    International Nuclear Information System (INIS)

    Sibello Hernandez, R.Y.; Alonso Hernandez, C.M.; Diaz Asencio, M.; Cartas Aguila, H. A.

    1999-01-01

    In this work the results are exposed obtained by the Laboratory of Environmental Surveillance in the radioactive characterization of the existent terrestrial ecosystem in the area of location of the Juragua Nuclear Power Plants in Cienfuegos, Cuba, starting from 1986 and up to 1993

  3. Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Pr...

  4. Aspects of the carbon cycle in terrestrial ecosystems of Northeastern Smaaland

    International Nuclear Information System (INIS)

    Tagesson, Torbern

    2006-02-01

    Boreal and temperate ecosystems of the northern hemisphere are important for the future development of global climate. In this study, the carbon cycle has been studied in a pine forest, a meadow, a spruce forest and two deciduous forests in the Simpevarp investigation area in southern Sweden (57 deg 5 min N, 34 deg 55 min E). Ground respiration and ground Gross Primary Production (GPP) has been measured three times during spring 2004 with the closed chamber technique. Soil temperature, soil moisture and Photosynthetically Active Radiation (PAR) were also measured. An exponential regression with ground respiration against soil temperature was used to extrapolate respiration over spring 2004. A logarithmic regression with ground GPP against PAR was used to extrapolate GPP in meadow over spring 2004. Ground respiration is affected by soil temperature in all ecosystems but pine, but still it only explains a small part of the variation in respiration and this indicates that other abiotic factors also have an influence. Soil moisture affects respiration in spruce and one of the deciduous ecosystems. A comparison between measured and extrapolated ground respiration indicated that soil temperature could be used to extrapolate ground respiration. PAR is the main factor influencing GPP in all ecosystems but pine, still it could not be used to extrapolate GPP in meadow since too few measurements were done and they were from different periods of spring. Soil moisture did not have any significant effect on GPP. A Dynamic Global Vegetation Model, a DGVM called LPJ-GUESS, was downscaled to the Simpevarp investigation area. The downscaled DGVM was evaluated against measured respiration and soil organic acids for all five ecosystems. In meadow, it was evaluated against Net Primary Production, NPP. For the forest ecosystems, it was evaluated against tree layer carbon pools. The evaluation indicated that the DGVM is reasonably well downscaled to the Simpevarp investigation area and

  5. Implications of Climate Change for Northern Canada: Freshwater, Marine, and Terrestrial Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Prowse, Terry D.; Wrona, Fred J. (Water and Climate Impacts Research Centre, Environment Canada, Dept. of Geography, Univ. of Victoria, Victoria, BC (Canada)). e-mail: terry.prowse@ec.gc.caa; Furgal, Chris (Indigenous Environmental Studies Program, Trent Univ., Peterborough, ON (Canada)); Reist, James D. (Fisheries and Oceans Canada, 501 Univ. Crescent, Winnipeg, MB (Canada))

    2009-07-15

    Climate variability and change is projected to have significant effects on the physical, chemical, and biological components of northern Canadian marine, terrestrial, and freshwater systems. As the climate continues to change, there will be consequences for biodiversity shifts and for the ranges and distribution of many species with resulting effects on availability, accessibility, and quality of resources upon which human populations rely. This will have implications for the protection and management of wildlife, fish, and fisheries resources; protected areas; and forests. The northward migration of species and the disruption and competition from invading species are already occurring and will continue to affect marine, terrestrial, and freshwater communities. Shifting environmental conditions will likely introduce new animal-transmitted diseases and redistribute some existing diseases, affecting key economic resources and some human populations. Stress on populations of iconic wildlife species, such as the polar bear, ringed seals, and whales, will continue as a result of changes in critical sea-ice habitat interactions. Where these stresses affect economically and culturally important species, they will have significant effects on people and regional economies. Further integrated, field-based monitoring and research programs, and the development of predictive models are required to allow for more detailed and comprehensive projections of change to be made, and to inform the development and implementation of appropriate adaptation, wildlife, and habitat conservation and protection strategies

  6. Effect of climate warming on the annual terrestrial net ecosystem CO2 exchange globally in the boreal and temperate regions.

    Science.gov (United States)

    Zhang, Zhiyuan; Zhang, Renduo; Cescatti, Alessandro; Wohlfahrt, Georg; Buchmann, Nina; Zhu, Juan; Chen, Guanhong; Moyano, Fernando; Pumpanen, Jukka; Hirano, Takashi; Takagi, Kentaro; Merbold, Lutz

    2017-06-08

    The net ecosystem CO 2 exchange is the result of the imbalance between the assimilation process (gross primary production, GPP) and ecosystem respiration (RE). The aim of this study was to investigate temperature sensitivities of these processes and the effect of climate warming on the annual terrestrial net ecosystem CO 2 exchange globally in the boreal and temperate regions. A database of 403 site-years of ecosystem flux data at 101 sites in the world was collected and analyzed. Temperature sensitivities of rates of RE and GPP were quantified with Q 10 , defined as the increase of RE (or GPP) rates with a temperature rise of 10 °C. Results showed that on the annual time scale, the intrinsic temperature sensitivity of GPP (Q 10sG ) was higher than or equivalent to the intrinsic temperature sensitivity of RE (Q 10sR ). Q 10sG was negatively correlated to the mean annual temperature (MAT), whereas Q 10sR was independent of MAT. The analysis of the current temperature sensitivities and net ecosystem production suggested that temperature rise might enhance the CO 2 sink of terrestrial ecosystems both in the boreal and temperate regions. In addition, ecosystems in these regions with different plant functional types should sequester more CO 2 with climate warming.

  7. A lake classification concept for a more accurate global estimate of the dissolved inorganic carbon export from terrestrial ecosystems to inland waters

    Science.gov (United States)

    Engel, Fabian; Farrell, Kaitlin J.; McCullough, Ian M.; Scordo, Facundo; Denfeld, Blaize A.; Dugan, Hilary A.; de Eyto, Elvira; Hanson, Paul C.; McClure, Ryan P.; Nõges, Peeter; Nõges, Tiina; Ryder, Elizabeth; Weathers, Kathleen C.; Weyhenmeyer, Gesa A.

    2018-04-01

    The magnitude of lateral dissolved inorganic carbon (DIC) export from terrestrial ecosystems to inland waters strongly influences the estimate of the global terrestrial carbon dioxide (CO2) sink. At present, no reliable number of this export is available, and the few studies estimating the lateral DIC export assume that all lakes on Earth function similarly. However, lakes can function along a continuum from passive carbon transporters (passive open channels) to highly active carbon transformers with efficient in-lake CO2 production and loss. We developed and applied a conceptual model to demonstrate how the assumed function of lakes in carbon cycling can affect calculations of the global lateral DIC export from terrestrial ecosystems to inland waters. Using global data on in-lake CO2 production by mineralization as well as CO2 loss by emission, primary production, and carbonate precipitation in lakes, we estimated that the global lateral DIC export can lie within the range of {0.70}_{-0.31}^{+0.27} to {1.52}_{-0.90}^{+1.09} Pg C yr-1 depending on the assumed function of lakes. Thus, the considered lake function has a large effect on the calculated lateral DIC export from terrestrial ecosystems to inland waters. We conclude that more robust estimates of CO2 sinks and sources will require the classification of lakes into their predominant function. This functional lake classification concept becomes particularly important for the estimation of future CO2 sinks and sources, since in-lake carbon transformation is predicted to be altered with climate change.

  8. Change in terrestrial ecosystem water-use efficiency over the last three decades.

    Science.gov (United States)

    Huang, Mengtian; Piao, Shilong; Sun, Yan; Ciais, Philippe; Cheng, Lei; Mao, Jiafu; Poulter, Ben; Shi, Xiaoying; Zeng, Zhenzhong; Wang, Yingping

    2015-06-01

    facilitate mechanistic understanding of the carbon-water interactions over terrestrial ecosystems under global change. © 2015 John Wiley & Sons Ltd.

  9. Effects of active forest fire on terrestrial ecosystem production and greenhouse gas emissions

    Science.gov (United States)

    Sannigrahi, Srikanta; Rahmat, Shahid; Bhatt, Sandeep; Rana, Virendra

    2017-04-01

    The forest fire is one of the most catalysing agents which degrade an ecosystems leading to the loss of net and gross primary productivity (NPP & GPP) and carbon sequestration service. Additionally, it can suppress the efficiency of service providing capacity of an ecosystem throughout the time and space. Remote sensing-based forest fire estimation in a diverse ecosystem is very much essential for mitigating the biodiversity and productivity losses due to the forest fire. Satellite-based Land Surface Temperature (LST) has been calculated for the pre-fire and fire years to identify the burn severity hotspot across all eco-regions in the Lower Himalaya region. Several burn severity indices: Normalized Burn Ratio (NBR), Burnt Area Index (BAI), Normalized Multiband Drought Index (NMDI), Soil Adjusted Vegetation Index (SAVI), Global Environmental Monitoring Index (GEMI), Enhance Vegetation Index (EVI) have been used in this study to quantify the spatial and temporal changes (delta) of the selected indices. Two Light Use Efficiency (LUE) models: Carnegie- Ames-Stanford-Approach (CASA) and Vegetation Photosynthesis Model (VPM) have been used to quantify the terrestrial Net Primary Productivity (NPP) in the pre-fire and fire years across all biomes of the region. A novel approach has been preceded in this field to demonstrate the correlation between forest fire density (FFD) and NPP. A strong positive correlation was found between burn severity indices and predicted NPP: BAI and NPP (r = 0.49), NBR and NPP: (r = 0.58), EVI and NPP: (r = 0.72), SAVI and NPP: (r = 0.67), whereas, a negative association has noted between the NMDI and NPP: (r = -0.36) during the both studied years. Results have shown that the NPP is highly correlated with the forest fire density (R2 = 0.75, RMSE = 5.03 gC m-2 month-1). The estimated LST of the individual fire days has witnessed a sharp temperature increase by > 6oC - 9oC in comparison to the non-fire days clearly indicates high fire risk (in

  10. An Inter-comparison of Vegetation Greenness From Satellite Observations and a Terrestrial Ecosystem Model

    Science.gov (United States)

    Twine, T. E.; Kucharik, C. J.

    2004-12-01

    Terrestrial ecosystem models simulate the structure and functioning of vegetation as well as the exchanges of energy, water, and nutrients between components of the land surface and the atmosphere. While these models use numerical methods that are based on a wealth of observations, the accuracy of a model in simulating ecosystem processes at the regional scale is difficult to test because evaluation has traditionally relied on in situ measurements made at point locations (on the order of several m2 in area). Daily satellite observations may provide a means for better model evaluation through the sensing of ecosystems at regional to global scales; however, there are several challenges to this method of evaluation. Satellite measurements may suffer from signal corruption from the earth's atmosphere, sensor and solar geometry issues, and sensor calibration problems. In addition, most of the quantities of interest in model evaluation must be derived from the reflectances detected by the sensor, which increases the uncertainty in these variables, and are usually given to the community after downgrading the daily values to monthly average values. In this study, we compare twenty years of Pathfinder Advanced Very High Resolution Radiometer (AVHRR) monthly-averaged measurements of the Normalized Difference Vegetation Index (NDVI), the fraction of photosynthetically active radiation absorbed by the vegetation canopy (FPAR), and the leaf area index (LAI) with output from the Integrated Biosphere Simulator (IBIS) over grasslands, croplands, and forests within the United States. Because two variables, FPAR and LAI (secondary, or derived quantities), have different relationships with NDVI (primary quantity), this three-variable evaluation may provide a method of assessing uncertainty in both simulated and observed (derived) quantities. Results show that IBIS captures the observed seasonality and magnitude of NDVI over all biomes, although FPAR and LAI are underestimated in

  11. Modeling extreme drought impacts on terrestrial ecosystems when thresholds are exceeded

    Science.gov (United States)

    Holm, J. A.; Rammig, A.; Smith, B.; Medvigy, D.; Lichstein, J. W.; Dukes, J. S.; Allen, C. D.; Beier, C.; Larsen, K. S.; Ficken, C. D.; Pockman, W.; Anderegg, W.; Luo, Y.

    2016-12-01

    Recent IPCC Assessment Reports suggest that with predicted climate changes future precipitation- and heat-related extreme events are becoming stronger and more frequent with potential for prolonged droughts. To prepare for these changes and their impacts, we need to develop a better understanding of terrestrial ecosystem responses to extreme drought events. In particular, we focus here on large-extent and long-lasting extreme drought events with noticeable impacts on the functioning of forested ecosystems. While most of ecosystem manipulative experiments have been motivated by ongoing and predicted climate change, the majority only applied relatively moderate droughts, not addressing the "very" extreme tail of these scenarios, i.e. "extreme extremes (EEs)". We explore the response of forest ecosystems to EEs using two demographic-based dynamic global vegetation models (DGVMs) (i.e. ED2, LPJ-GUESS) in which the abundances of different plant functional types, as well as tree size- and age-class structure, are emergent properties of resource competition. We evaluate the model's capabilities to represent extreme drought scenarios (i.e., 50% and 90% reduction in precipitation for 1-year, 2-year, and 4-year drought scenarios) at two dry forested sites: Palo Verde, Costa Rica (i.e. tropical) and EucFACE, Australia (i.e. temperate). Through the DGVM modeling outcomes we determine the following five testable hypotheses for future experiments: 1) EEs cannot be extrapolated from mild extremes due to plant plasticity and functional composition. 2) Response to EEs depends on functional diversity, trait combinations, and phenology, such that both models predicted even after 100 years plant biomass did not recover. 3) Mortality from drought reduces the pressure on resources and prevents further damage by subsequent years of drought. 4) Early successional stands are more vulnerable to extreme droughts while older stand are more resilient. 5) Elevated atmospheric CO2 alleviates

  12. Shifts of community composition and population density substantially affect ecosystem function despite invariant richness

    NARCIS (Netherlands)

    Spaak, Jurg W.; Baert, Jan M.; Baird, Donald J.; Eisenhauer, Nico; Maltby, Lorraine; Pomati, Francesco; Radchuk, Viktoriia; Rohr, Jason R.; Brink, van den Paul J.; Laender, De Frederik

    2017-01-01

    There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community

  13. Enhanced water use efficiency in global terrestrial ecosystems under increasing aerosol loadings

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaoliang; Chen, Min; Liu, Yaling; Miralles, Diego G.; Wang, Faming

    2017-05-01

    Aerosols play a crucial role in the climate system, affecting incoming radiation and cloud formation. Based on a modelling framework that couples ecosystem processes with the atmospheric transfer of radiation, we analyze the effect of aerosols on surface incoming radiation, gross primary productivity (GPP), water losses from ecosystems through evapotranspiration (ET) and ecosystem water use efficiency (WUE, defined as GPP/ET) for 2003–2010 and validate them at global FLUXNET sites. The total diffuse radiation increases under relatively low or intermediate aerosol loadings, but decreases under more polluted conditions. We find that aerosol-induced changes in GPP depend on leaf area index, aerosol loading and cloudiness. Specifically, low and moderate aerosol loadings cause increases in GPP for all plant types, while heavy aerosol loadings result in enhancement (decrease) in GPP for dense (sparse) vegetation. On the other hand, ET is mainly negatively affected by aerosol loadings due to the reduction in total incoming radiation. Finally, WUE shows a consistent rise in all plant types under increasing aerosol loadings. Overall, the simulated daily WUE compares well with observations at 43 eddy-covariance tower sites (R2=0.84 and RMSE=0.01gC (kg H2O)-1) with better performance at forest sites. In addition to the increasing portions of diffuse light, the rise in WUE is also favored by the reduction in radiation- and heat-stress caused by the aerosols, especially for wet and hot climates.

  14. A new Cretaceous terrestrial ecosystem from Gondwana with the description of a new sauropod dinosaur

    Directory of Open Access Journals (Sweden)

    Jorge O. Calvo

    2007-09-01

    Full Text Available A unique site at the northern area of Patagonia (Neuquén, Argentina reveals a terrestrial ecosystem preserved in a detail never reported before in a Late Cretaceous deposit. An extraordinary diversity and abundance of fossils was found concentrated in a 0.5 m horizon in the same quarry, including a new titanosaur sauropod, Futalognkosaurus dukei n.gen., n.sp, which is the most complete giant dinosaur known so far. Several plant leaves, showing a predominance of angiosperms over gymnosperms that likely constituted the diet of F. dukei were found too. Other dinosaurs (sauropods, theropods, ornithopods, crocodylomorphs, pterosaurs, and fishes were also discovered, allowing a partial reconstruction of this Gondwanan continental ecosystem.Um depósito fóssil na região norte da Patagônia (Neuquén, Argentina revela um ecossistema nunca antes registrado a este nível de detalhes em depósitos do Cretáceo Superior. Uma diversidade e abundância extraordinária de fósseis encontra-se concentrada em uma camada de 0,5 m no mesmo sítio, incluindo um novo saurópodo titanossaurídeo, Futalognkosaurus dukei n. gen, n. sp., que é o mais completo dinossauro gigante encontrado até a presente data. Foram descobertas váriasfolhas de plantas indicando a predominância de angiospermas sobre gimnospermas que possivelmente formavam a base da dieta de F. dukei. Outros dinossauros (saurópodes, terópodes, ornitópodes, crocodilomorfos, pterossauros e peixes foram também encontrados possibilitando a reconstrução parcialdeste ecossistema continental do Gondwana.

  15. Improving the Characterization of Arctic Coastline Ecosystem Change near Utqiagvik, Alaska Utilizing Multiyear Terrestrial Laser Scanning

    Science.gov (United States)

    Escarzaga, S. M.; Cody, R. P.; Vargas, S. A., Jr.; Fuson, T.; Hodge, B. E.; Tweedie, C. E.

    2017-12-01

    The Arctic Ocean comprises the largest coastline on Earth and is undergoing environmental change on a level disproportionate to those in lower-latitudes. In the US Arctic, coastal erosion rates along the North Slope of Alaska show that they are among highest in the nation at an average rate of 1.4 meters per year. Despite their importance to biogeochemical cycling, Native village infrastructure and providing pristine species habitat, Arctic coastlines and near shore environments are relatively understudied due to logistical challenges of conducting fieldwork in these locations. This study expands on past efforts which showed dGPS foot surveys work well at describing planar erosion on less complex permafrost bluff types like those seen on the higher-energy coasts east of Utqiagvik, Alaska along the Beaufort Sea where the main mechanism of erosion happens by block failure caused by wave action. However, coastal bluffs along the Chukchi Sea to the west are more complex and variable in terms of form and mechanisms of erosion. Here, where wide beaches tend to buffer wave action, thermal erosion and permafrost slumping produce slower erosion rates. Terrestrial Laser Scanning (TLS) has been applied across a multitude of terrain types, including coastlines spanning various ecosystems. Additionally, this approach allows 3D modeling of fine scale geomorphological features which can facilitate modeling of erosion rates in these areas. This study utilizes a six year time series of TLS on a section of coastal permafrost bluff along the Chukchi Sea south of Utqiagvik. The aim of the work presented is to better understand spatio-temporal trends of coastal bluff face erosion, bluff top subsidence and how these landscape microtopographic changes are coupled to ecosystem changes and land cover types. Preliminary analysis suggests a high rate of stability of the bluff face over the TLS record with most of the detectable permafrost subsidence happening closer to the coastal bluff edge.

  16. Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    Potter, C.; Klooster, S.; Huete, A.; Genovese, V.; Bustamante, M.; Ferreira, L. Guimaraes; deOliveira, R. C., Jr.; Zepp, R.

    2009-01-01

    A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Net ecosystem production (NEP) flux for atmospheric CO2 in the region for these years was estimated. Consistently high carbon sink fluxes in terrestrial ecosystems on a yearly basis were found in the western portions of the states of Acre and Rondonia and the northern portions of the state of Par a. These areas were not significantly impacted by the 2002-2003 El Nino event in terms of net annual carbon gains. Areas of the region that show periodically high carbon source fluxes from terrestrial ecosystems to the atmosphere on yearly basis were found throughout the state of Maranhao and the southern portions of the state of Amazonas. As demonstrated though tower site comparisons, NEP modeled with monthly MODIS Enhanced Vegetation Index (EVI) inputs closely resembles the measured seasonal carbon fluxes at the LBA Tapajos tower site. Modeling results suggest that the capacity for use of MODIS Enhanced Vegetation Index (EVI) data to predict seasonal uptake rates of CO2 in Amazon forests and Cerrado woodlands is strong.

  17. Terrestrial carbon sinks in the Brazilian Amazon and Cerrado region predicted from MODIS satellite data and ecosystem modeling

    Directory of Open Access Journals (Sweden)

    C. Potter

    2009-06-01

    Full Text Available A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000–2004. Net ecosystem production (NEP flux for atmospheric CO2 in the region for these years was estimated. Consistently high carbon sink fluxes in terrestrial ecosystems on a yearly basis were found in the western portions of the states of Acre and Rondônia and the northern portions of the state of Pará. These areas were not significantly impacted by the 2002–2003 El Niño event in terms of net annual carbon gains. Areas of the region that show periodically high carbon source fluxes from terrestrial ecosystems to the atmosphere on yearly basis were found throughout the state of Maranhão and the southern portions of the state of Amazonas. As demonstrated though tower site comparisons, NEP modeled with monthly MODIS Enhanced Vegetation Index (EVI inputs closely resembles the measured seasonal carbon fluxes at the LBA Tapajos tower site. Modeling results suggest that the capacity for use of MODIS Enhanced Vegetation Index (EVI data to predict seasonal uptake rates of CO2 in Amazon forests and Cerrado woodlands is strong.

  18. Global Monthly CO2 Flux Inversion Based on Results of Terrestrial Ecosystem Modeling

    Science.gov (United States)

    Deng, F.; Chen, J.; Peters, W.; Krol, M.

    2008-12-01

    Most of our understanding of the sources and sinks of atmospheric CO2 has come from inverse studies of atmospheric CO2 concentration measurements. However, the number of currently available observation stations and our ability to simulate the diurnal planetary boundary layer evolution over continental regions essentially limit the number of regions that can be reliably inverted globally, especially over continental areas. In order to overcome these restrictions, a nested inverse modeling system was developed based on the Bayesian principle for estimating carbon fluxes of 30 regions in North America and 20 regions for the rest of the globe. Inverse modeling was conducted in monthly steps using CO2 concentration measurements of 5 years (2000 - 2005) with the following two models: (a) An atmospheric transport model (TM5) is used to generate the transport matrix where the diurnal variation n of atmospheric CO2 concentration is considered to enhance the use of the afternoon-hour average CO2 concentration measurements over the continental sites. (b) A process-based terrestrial ecosystem model (BEPS) is used to produce hourly step carbon fluxes, which could minimize the limitation due to our inability to solve the inverse problem in a high resolution, as the background of our inversion. We will present our recent results achieved through a combination of the bottom-up modeling with BEPS and the top-down modeling based on TM5 driven by offline meteorological fields generated by the European Centre for Medium Range Weather Forecast (ECMFW).

  19. Convergence of microbial assimilations of soil carbon, nitrogen, phosphorus, and sulfur in terrestrial ecosystems

    Science.gov (United States)

    Xu, Xiaofeng; Hui, Dafeng; King, Anthony W.; Song, Xia; Thornton, Peter E.; Zhang, Lihua

    2015-01-01

    How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P, and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P, and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils, and 42:6:1:0.4 for microbes. We found a convergence of the relationships between elements in soils and in soil microbial biomass across C, N, P, and S. The element concentrations in soil microbial biomass follow a homeostatic regulation curve with soil element concentrations across C, N, P and S, implying a unifying mechanism of microbial assimilating soil elements. This correlation explains the well-constrained C:N:P:S stoichiometry with a slightly larger variation in soils than in microbial biomass. Meanwhile, it is estimated that the minimum requirements of soil elements for soil microbes are 0.8 mmol C Kg−1 dry soil, 0.1 mmol N Kg−1 dry soil, 0.1 mmol P Kg−1 dry soil, and 0.1 mmol S Kg−1 dry soil, respectively. These findings provide a mathematical explanation of element imbalance in soils and soil microbial biomass, and offer insights for incorporating microbial contribution to nutrient cycling into Earth system models. PMID:26612423

  20. Convergence of microbial assimilations of soil carbon, nitrogen, phosphorus, and sulfur in terrestrial ecosystems.

    Science.gov (United States)

    Xu, Xiaofeng; Hui, Dafeng; King, Anthony W; Song, Xia; Thornton, Peter E; Zhang, Lihua

    2015-11-27

    How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P, and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P, and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils, and 42:6:1:0.4 for microbes. We found a convergence of the relationships between elements in soils and in soil microbial biomass across C, N, P, and S. The element concentrations in soil microbial biomass follow a homeostatic regulation curve with soil element concentrations across C, N, P and S, implying a unifying mechanism of microbial assimilating soil elements. This correlation explains the well-constrained C:N:P:S stoichiometry with a slightly larger variation in soils than in microbial biomass. Meanwhile, it is estimated that the minimum requirements of soil elements for soil microbes are 0.8 mmol C Kg(-1) dry soil, 0.1 mmol N Kg(-1) dry soil, 0.1 mmol P Kg(-1) dry soil, and 0.1 mmol S Kg(-1) dry soil, respectively. These findings provide a mathematical explanation of element imbalance in soils and soil microbial biomass, and offer insights for incorporating microbial contribution to nutrient cycling into Earth system models.

  1. An evaluation of the ecological and environmental security on China's terrestrial ecosystems.

    Science.gov (United States)

    Zhang, Hongqi; Xu, Erqi

    2017-04-11

    With rapid economic growth, industrialization, and urbanization, various ecological and environmental problems occur, which threaten and undermine the sustainable development and domestic survival of China. On the national scale, our progress remains in a state of qualitative or semi-quantitative evaluation, lacking a quantitative evaluation and a spatial visualization of ecological and environmental security. This study collected 14 indictors of water, land, air, and biodiversity securities to compile a spatial evaluation of ecological and environmental security in terrestrial ecosystems of China. With area-weighted normalization and scaling transformations, the veto aggregation (focusing on the limit indicator) and balanced aggregation (measuring balanced performance among different indicators) methods were used to aggregate security evaluation indicators. Results showed that water, land, air, and biodiversity securities presented different spatial distributions. A relatively serious ecological and environmental security crisis was found in China, but presented an obviously spatial variation of security evaluation scores. Hotspot areas at the danger level, which are scattered throughout the entirety of the country, were identified. The spatial diversities and causes of ecological and environmental problems in different regions were analyzed. Spatial integration of regional development and proposals for improving the ecological and environmental security were put forward.

  2. The SMAP Level 4 Carbon PRODUCT for Monitoring Terrestrial Ecosystem-Atmosphere CO2 Exchange

    Science.gov (United States)

    Jones, L. A.; Kimball, J. S.; Madani, N.; Reichle, R. H.; Glassy, J.; Ardizzone, J/

    2016-01-01

    The NASA Soil Moisture Active Passive (SMAP) mission Level 4 Carbon (L4_C) product provides model estimates of Net Ecosystem CO2 exchange (NEE) incorporating SMAP soil moisture information as a primary driver. The L4_C product provides NEE, computed as total respiration less gross photosynthesis, at a daily time step and approximate 14-day latency posted to a 9-km global grid summarized by plant functional type. The L4_C product includes component carbon fluxes, surface soil organic carbon stocks, underlying environmental constraints, and detailed uncertainty metrics. The L4_C model is driven by the SMAP Level 4 Soil Moisture (L4_SM) data assimilation product, with additional inputs from the Goddard Earth Observing System, Version 5 (GEOS-5) weather analysis and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. The L4_C data record extends from March 2015 to present with ongoing production. Initial comparisons against global CO2 eddy flux tower measurements, satellite Solar Induced Canopy Florescence (SIF) and other independent observation benchmarks show favorable L4_C performance and accuracy, capturing the dynamic biosphere response to recent weather anomalies and demonstrating the value of SMAP observations for monitoring of global terrestrial water and carbon cycle linkages.

  3. Fogwater deposition modeling for terrestrial ecosystems: A review of developments and measurements

    Science.gov (United States)

    Katata, Genki

    2014-07-01

    Recent progress in modeling fogwater (and low cloud water) deposition over terrestrial ecosystems during fogwater droplet interception by vegetative surfaces is reviewed. Several types of models and parameterizations for fogwater deposition are discussed with comparing assumptions, input parameter requirements, and modeled processes. The relationships among deposition velocity of fogwater (Vd) in model results, wind speed, and plant species structures associated with literature values are gathered for model validation. Quantitative comparisons between model results and observations in forest environments revealed differences as large as 2 orders of magnitude, which are likely caused by uncertainties in measurement techniques over heterogeneous landscapes. Results from the literature review show that Vd values ranged from 2.1 to 8.0 cm s-1 for short vegetation, whereas Vd = 7.7-92 cm s-1 and 0-20 cm s-1 for forests measured by throughfall-based methods and the eddy covariance method, respectively. This review also discusses the current understanding of the impacts of fogwater deposition on atmosphere-land interactions and over complex terrain based on results from numerical studies. Lastly, future research priorities in innovative modeling and observational approaches for model validation are outlined.

  4. Nitrogen and carbon cycling in a grassland community ecosystem as affected by elevated atmospheric CO2

    Science.gov (United States)

    Increasing global atmospheric CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystem and the long-term storage of C and N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L.) Willd (...

  5. Predicting ecosystem dynamics at regional scales: an evaluation of a terrestrial biosphere model for the forests of northeastern North America.

    Science.gov (United States)

    Medvigy, David; Moorcroft, Paul R

    2012-01-19

    Terrestrial biosphere models are important tools for diagnosing both the current state of the terrestrial carbon cycle and forecasting terrestrial ecosystem responses to global change. While there are a number of ongoing assessments of the short-term predictive capabilities of terrestrial biosphere models using flux-tower measurements, to date there have been relatively few assessments of their ability to predict longer term, decadal-scale biomass dynamics. Here, we present the results of a regional-scale evaluation of the Ecosystem Demography version 2 (ED2)-structured terrestrial biosphere model, evaluating the model's predictions against forest inventory measurements for the northeast USA and Quebec from 1985 to 1995. Simulations were conducted using a default parametrization, which used parameter values from the literature, and a constrained model parametrization, which had been developed by constraining the model's predictions against 2 years of measurements from a single site, Harvard Forest (42.5° N, 72.1° W). The analysis shows that the constrained model parametrization offered marked improvements over the default model formulation, capturing large-scale variation in patterns of biomass dynamics despite marked differences in climate forcing, land-use history and species-composition across the region. These results imply that data-constrained parametrizations of structured biosphere models such as ED2 can be successfully used for regional-scale ecosystem prediction and forecasting. We also assess the model's ability to capture sub-grid scale heterogeneity in the dynamics of biomass growth and mortality of different sizes and types of trees, and then discuss the implications of these analyses for further reducing the remaining biases in the model's predictions.

  6. [Characteristics of terrestrial ecosystem primary productivity in East Asia based on remote sensing and process-based model].

    Science.gov (United States)

    Zhang, Fang-Min; Ju, Wei-Min; Chen, Jing-Ming; Wang, Shao-Qiang; Yu, Gui-Rui; Han, Shi-Jie

    2012-02-01

    Based on the bi-linearly interpolated meteorological reanalysis data from National Centers for Environmental Prediction, USA and by using the leaf area index data derived from the GIMMS NDVI to run the process-based Boreal Ecosystems Productivity Simulator (BEPS) model, this paper simulated and analyzed the spatiotemporal characteristics of the terrestrial ecosystem gross primary productivity (GPP) and net primary productivity (NPP) in East Asia in 2000-2005. Before regional simulating and calculating, the observation GPP data of different terrestrial ecosystem in 15 experimental stations of AsiaFlux network and the inventory measurements of NPP at 1300 sampling sites were applied to validate the BEPS GPP and NPP. The results showed that BEPS could well simulate the changes in GPP and NPP of different terrestrial ecosystems, with the R2 ranging from 0.86 to 0.99 and the root mean square error (RMSE) from 0.2 to 1.2 g C x m(-2) x d(-1). The simulated values by BEPS could explain 78% of the changes in annual NPP, and the RMSE was 118 g C x m(-2) x a(-1). In 2000-2005, the averaged total GPP and total NPP of the terrestrial ecosystems in East Asia were 21.7 and 10.5 Pg C x a(-1), respectively, and the GPP and NPP exhibited similar spatial and temporal variation patterns. During the six years, the total NPP of the terrestrial ecosystems varied from 10.2 to 10.7 Pg C x a(-1), with a coefficient of variation being 2. 2%. High NPP (above 1000 g C x m(-2) x a(-1)) occurred in the southeast island countries, while low NPP (below 30 g C x m(-2) x a(-1)) occurred in the desert area of Northwest China. The spatial patterns of NPP were mainly attributed to the differences in the climatic variables across East Asia. The NPP per capita also varied greatly among different countries, which was the highest (70217 kg C x a(-1)) in Mongolia, far higher than that (1921 kg C x a(-1)) in China, and the lowest (757 kg C x a(-1)) in India.

  7. An organic record of terrestrial ecosystem collapse and recovery at the Triassic-Jurassic boundary in East Greenland

    Science.gov (United States)

    Williford, Kenneth H.; Grice, Kliti; Holman, Alexander; McElwain, Jennifer C.

    2014-02-01

    Terrestrial ecosystem collapse at the end of the Triassic Period coincided with a major mass extinction in the marine realm and has been linked to increasing atmospheric carbon dioxide, global warming, and fire activity. Extractable hydrocarbons in samples from the fluvial Triassic-Jurassic boundary section at Astartekløft, East Greenland were analyzed to investigate the molecular and isotopic organic record of biotic and environmental change during this event. Carbon isotopic compositions of individual plant wax lipids show a >4‰ negative excursion coinciding with peak extinction and a further decrease of 2‰ coinciding with peak pCO2 as estimated from the stomatal indices of fossil Gingkoales. An increase of ˜30‰ in the hydrogen isotopic compositions of the same plant wax lipids coincides with ecosystem collapse, suggesting that the biotic crisis was accompanied by strong hydrologic change. Concentrations of polycyclic aromatic hydrocarbons related to combustion also increase together with abrupt plant diversity loss and peak with fossil charcoal abundance and maximum plant turnover, supporting the role of fire in terrestrial extinctions. Anomalously high concentrations of a monoaromatic diterpenoid related to gymnosperm resin derivatives (and similar to dehydroabietane) occur uniquely in samples from the boundary bed, indicating that environmental stress factors leading to peak plant extinction stimulated increased resin production, and that plant resin derivatives may be effective biomarkers of terrestrial ecosystem stress.

  8. A new theoretical approach to terrestrial ecosystem science based on multiscale observations and eco-evolutionary optimality principles

    Science.gov (United States)

    Prentice, Iain Colin; Wang, Han; Cornwell, William; Davis, Tyler; Dong, Ning; Evans, Bradley; Keenan, Trevor; Peng, Changhui; Stocker, Benjamin; Togashi, Henrique; Wright, Ian

    2016-04-01

    Ecosystem science focuses on biophysical interactions of organisms and their abiotic environment, and comprises vital aspects of Earth system function such as the controls of carbon, water and energy exchanges between ecosystems and the atmosphere. Global numerical models of these processes have proliferated, and have been incorporated as standard components of Earth system models whose ambitious goal is to predict the coupled behaviour of the oceans, atmosphere and land on time scales from minutes to millennia. Unfortunately, however, the performance of most current terrestrial ecosystem models is highly unsatisfactory. Models typically fail the most basic observational benchmarks, and diverge greatly from one another when called upon to predict the response of ecosystem function and composition to environmental changes beyond the narrow range for which they were developed. This situation seems to have arisen for two inter-related reasons. First, general principles underlying many basic terrestrial biogeochemical processes have been neither clearly formulated nor adequately tested. Second, extensive observational data sets that could be used to test process formulations have become available only quite recently, long postdating the emergence of the current modelling paradigm. But the situation has changed now and ecosystem science needs to change too, to reflect both recent theoretical advances and the vast increase in the availability of relevant data sets at scales from the leaf to the globe. This presentation will outline an emerging mathematical theory that links biophysical plant and ecosystem processes through testable hypotheses derived from the principle of optimization by natural selection. The development and testing of this theory has depended on the availability of extensive data sets on climate, leaf traits (including δ13C measurements), and ecosystem properties including green vegetation cover and land-atmosphere CO2 fluxes. Achievements to date

  9. Intercomparison of Terrestrial Laser Scanning Instruments for Assessing Forested Ecosystems: A Brisbane Field Experiment

    Science.gov (United States)

    Armston, J.; Newnham, G.; Strahler, A. H.; Schaaf, C.; Danson, M.; Gaulton, R.; Zhang, Z.; Disney, M.; Sparrow, B.; Phinn, S. R.; Schaefer, M.; Burt, A.; Counter, S.; Erb, A.; Goodwin, N.; Hancock, S.; Howe, G.; Johansen, K.; Li, Z.; Lollback, G.; Martel, J.; Muir, J.; Paynter, I.; Saenz, E.; Scarth, P.; Tindall, D.; Walker, L.; Witte, C.; Woodgate, W.; Wu, S.

    2013-12-01

    During 28th July - 3rd August, 2013, an international group of researchers brought five terrestrial laser scanners (TLS) to long-term monitoring plots in three eucalyptus-dominated woodland sites near Brisbane, Queensland, Australia, to acquire scans at common locations for calibration and intercomparison.They included: DWEL - a dual-wavelength full-waveform laser scanner (Boston U., U. Massachusetts Lowell, U. Massachusetts Boston, USA) SALCA - a dual-wavelength full-waveform laser scanner (U. Salford, UK) CBL - a canopy biomass lidar, a small ultraportable low-cost multiple discrete return scanner (U. Massachusetts Boston, USA) Riegl VZ400 - a survey-grade commercial waveform scanner (Queensland Government and TERN, U. Queensland, Australia) FARO Focus 3D - a lightweight commercial phase-shift ranging laser scanner (U. Southern Queensland) Two plots were scanned at Karawatha Forest Park, a Terrestrial Ecosystem Research Network (TERN) Supersite, and one plot at D'Aguilar National Park. At each 50 x 100 m plot, a center scan point was surrounded by four scan points located 25 m away in a cross pattern allowing for 3-D reconstructions of scan sites in the form of point clouds. At several center points, multiple instrument configurations (i.e. different beam divergence, angular resolution, pulse rate) were acquired to test the impact of instrument specifications on separation of woody and non-woody materials and estimation of vegetation structure parameters. Three-dimensional Photopoint photographic panoramas were also acquired, providing reconstructions of stems in the form of point clouds using photogrammetric correlation methods. Calibrated reflectance targets were also scanned to compare instrument geometric and radiometric performance. Ancillary data included hemispherical photos, TRAC LAI/clumping measurements, spectra of leaves, bark, litter, and other target components. Wet and dry leaf weights determined water content. Planned intercomparison topics and

  10. Endoparasites in the feces of arctic foxes in a terrestrial ecosystem in Canada.

    Science.gov (United States)

    Elmore, Stacey A; Lalonde, Laura F; Samelius, Gustaf; Alisauskas, Ray T; Gajadhar, Alvin A; Jenkins, Emily J

    2013-12-01

    The parasites of arctic foxes in the central Canadian Arctic have not been well described. Canada's central Arctic is undergoing dramatic environmental change, which is predicted to cause shifts in parasite and wildlife species distributions, and trophic interactions, requiring that baselines be established to monitor future alterations. This study used conventional, immunological, and molecular fecal analysis techniques to survey the current gastrointestinal endoparasite fauna currently present in arctic foxes in central Nunavut, Canada. Ninety-five arctic fox fecal samples were collected from the terrestrial Karrak Lake ecosystem within the Queen Maud Gulf Migratory Bird Sanctuary. Samples were examined by fecal flotation to detect helminths and protozoa, immunofluorescent assay (IFA) to detect Cryptosporidium and Giardia, and quantitative PCR with melt-curve analysis (qPCR-MCA) to detect coccidia. Positive qPCR-MCA products were sequenced and analyzed phylogenetically. Arctic foxes from Karrak Lake were routinely shedding eggs from Toxascaris leonina (63%). Taeniid (15%), Capillarid (1%), and hookworm eggs (2%), Sarcocystis sp. sporocysts 3%), and Eimeria sp. (6%), and Cystoisospora sp. (5%) oocysts were present at a lower prevalence on fecal flotation. Cryptosporidium sp. (9%) and Giardia sp. (16%) were detected by IFA. PCR analysis detected Sarcocystis (15%), Cystoisospora (5%), Eimeria sp., and either Neospora sp. or Hammondia sp. (1%). Through molecular techniques and phylogenetic analysis, we identified two distinct lineages of Sarcocystis sp. present in arctic foxes, which probably derived from cervid and avian intermediate hosts. Additionally, we detected previously undescribed genotypes of Cystoisospora. Our survey of gastrointestinal endoparasites in arctic foxes from the central Canadian Arctic provides a unique record against which future comparisons can be made.

  11. Terrestrial ecosystem collapse associated to the K-Pg boundary and dinosaur extinction: palynological evidences

    Science.gov (United States)

    Bercovici, A.; Vajda, V.; Lyson, T. R.; Chester, S. G. B.; Sargis, E. J.; Pearson, D. A.; Joyce, W. G.

    2012-04-01

    We report here the discovery of the stratigraphically youngest in situ dinosaur specimen. This ceratopsian brow horn was found in southeastern Montana, in the Western Interior of the United States in a poorly rooted, silty mudstone floodplain deposit and only 13 centimeters below the palynologically defined K-Pg boundary. The boundary is identified using three criteria: 1) substantial decrease in diversity and abundance of Cretaceous pollen and spore taxa that completely disappear from the palynological record a few meters above the boundary, 2) the presence of a "fern spike", and 3) palynostratigraphical correlation to a nearby section where primary extraterrestrial impact markers are present (e.g., iridium anomaly, spherules and shocked quartz). The palynological record in the rock sequence immediately following the K-Pg boundary consistently indicates a sudden and major loss of the Cretaceous components across the North American record. During this rapid decline, the palynological assemblages are dominated by freshwater ferns (Azolla) and algae (usually Pediastrum sp. and Penetetrapites sp.) indicating generalized flooding in the area. The onset of the Paleocene sedimentation is subsequently announced by the presence of variegated beds, multiple lignite seams and small scale meandering river systems, starting with palynological associations that attest for reworking and erosion. The destabilization of terrestrial ecosystems is coincident with the markers of the K-Pg boundary, supporting a catastrophic event taking place over a very short duration. The in situ ceratopsian brow horn demonstrates that a gap devoid of non-avian dinosaur fossils in the last meters of the Cretaceous is artificial and thus inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K-Pg boundary asteroid impact event.

  12. The spatiotemporal variation in evapotranspiration of terrestrial ecosystems in China between 1982-2015

    Science.gov (United States)

    Lian, X.; Piao, S.; Li, X.

    2017-12-01

    Evapotranspiration (ET) is one of the most important fluxes in the terrestrial ecosystem, and play a vital role in regulating atmosphere-hydrosphere-biosphere interaction. Several studies have suggested that global ET has significantly increased in the past several decades, and that such increase has exhibited big spatial variability, but there are few detailed studies on the spatio-temporal change in ET over China. Combining remote-sensing and ground-based observations with a machine learning approach (model tree ensemble, MTE), this study investigate the spatiotemporal variation in ET in China during 1982 and 2015. Our results showed that mean annual ET in China is 552±14mm year-1, which is within range of estimates by previous studies (from 430 mm year-1 to 555 mm year-1). ET spatially decreases from southeast to northwest, with highest value appeared in humidity regions (more than 1400 mm year-1) and lowest value in arid regions (less than 200 mm year-1). Over the past three decades, ET in China significantly increased by 1.07 mm year-2 with remarkable spatial heterogeneity. The largest increase in ET appears in the eastern periphery of SiChuan Basin, which may be related to increase in temperature, solar radiation as well as enhancing vegetation productivity. Only 20% of study area show decrease in ET, which is mainly located in parts of the southeast, southwest and northeast of China. The regional decrease in ET is likely to be contributed by decrease in solar radiation and relative humidity. Although our finding of the significant increase in China's ET at the country scale is supported by five different ET products, there are still less agreement on the change in ET at the regional scale among different ET products.

  13. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, C.L.

    1994-09-01

    As a result of operations at the Savannah River Site (SRS), over 50 radionuclides have been released to the atmosphere and to onsite streams and seepage basins. Now, many of these radionuclides are available to aquatic and/or terrestrial organisms for uptake and cycling through the food chain. Knowledge about the uptake and cycling of these radionuclides is now crucial in evaluating waste management and clean-up alternatives for the site. Numerous studies have been conducted at the SRS over the past forty years to study the uptake and distribution of radionuclides in the Savannah River Site environment. In many instances, bioconcentration factors have been calculated to quantify the uptake of a radionuclide by an organism from the surrounding medium (i.e., soil or water). In the past, it has been common practice to use bioconcentration factors from the literature because site-specific data were not readily available. However, because of the variability of bioconcentration factors due to experimental or environmental conditions, site-specific data should be used when available. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at the Savannah River Site (SRS). An extensive literature search yielded site-specific bioconcentration factors for cesium, strontium, cobalt, plutonium, americium, curium, and tritium. These eight radionuclides have been the primary radionuclides studied at SRS because of their long half lives or because they are major contributors to radiological dose from exposure. For most radionuclides, it was determined that the site-specific bioconcentration factors were higher than those reported in literature. This report also summarizes some conditions that affect radionuclide bioavailability to and bioconcentration by aquatic and terrestrial organisms.

  14. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River Site

    International Nuclear Information System (INIS)

    Cummins, C.L.

    1994-09-01

    As a result of operations at the Savannah River Site (SRS), over 50 radionuclides have been released to the atmosphere and to onsite streams and seepage basins. Now, many of these radionuclides are available to aquatic and/or terrestrial organisms for uptake and cycling through the food chain. Knowledge about the uptake and cycling of these radionuclides is now crucial in evaluating waste management and clean-up alternatives for the site. Numerous studies have been conducted at the SRS over the past forty years to study the uptake and distribution of radionuclides in the Savannah River Site environment. In many instances, bioconcentration factors have been calculated to quantify the uptake of a radionuclide by an organism from the surrounding medium (i.e., soil or water). In the past, it has been common practice to use bioconcentration factors from the literature because site-specific data were not readily available. However, because of the variability of bioconcentration factors due to experimental or environmental conditions, site-specific data should be used when available. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at the Savannah River Site (SRS). An extensive literature search yielded site-specific bioconcentration factors for cesium, strontium, cobalt, plutonium, americium, curium, and tritium. These eight radionuclides have been the primary radionuclides studied at SRS because of their long half lives or because they are major contributors to radiological dose from exposure. For most radionuclides, it was determined that the site-specific bioconcentration factors were higher than those reported in literature. This report also summarizes some conditions that affect radionuclide bioavailability to and bioconcentration by aquatic and terrestrial organisms

  15. The role of UV-B radiation in aquatic and terrestrial ecosystems - an experimental and functional analysis of the evolution of UV-absorbing componist.

    NARCIS (Netherlands)

    Rozema, J.; Bjorn, L.O.; Bornman, J.F.; Gaberscik, A.; Hader, D.P.; Trost, T.; Germ, M.; Klisch, M.; Groniger, A.; Sinha, R.P.; Lebert, M.; He, Y.Y.; Buffoni-Hall, R.; Bakker, N.; van de Staaij, J.W.M.; Meijkamp, B.B.

    2002-01-01

    We analysed and compared the functioning of UV-B screening pigments in plants from marine, fresh water and terrestrial ecosystems, along the evolutionary line of cyanobacteria, unicellular algae, primitive multicellular algae, charophycean algae, lichens, mosses and higher plants, including

  16. Organic carbon stock modelling for the quantification of the carbon sinks in terrestrial ecosystems

    Science.gov (United States)

    Durante, Pilar; Algeet, Nur; Oyonarte, Cecilio

    2017-04-01

    Given the recent environmental policies derived from the serious threats caused by global change, practical measures to decrease net CO2 emissions have to be put in place. Regarding this, carbon sequestration is a major measure to reduce atmospheric CO2 concentrations within a short and medium term, where terrestrial ecosystems play a basic role as carbon sinks. Development of tools for quantification, assessment and management of organic carbon in ecosystems at different scales and management scenarios, it is essential to achieve these commitments. The aim of this study is to establish a methodological framework for the modeling of this tool, applied to a sustainable land use planning and management at spatial and temporal scale. The methodology for carbon stock estimation in ecosystems is based on merger techniques between carbon stored in soils and aerial biomass. For this purpose, both spatial variability map of soil organic carbon (SOC) and algorithms for calculation of forest species biomass will be created. For the modelling of the SOC spatial distribution at different map scales, it is necessary to fit in and screen the available information of soil database legacy. Subsequently, SOC modelling will be based on the SCORPAN model, a quantitative model use to assess the correlation among soil-forming factors measured at the same site location. These factors will be selected from both static (terrain morphometric variables) and dynamic variables (climatic variables and vegetation indexes -NDVI-), providing to the model the spatio-temporal characteristic. After the predictive model, spatial inference techniques will be used to achieve the final map and to extrapolate the data to unavailable information areas (automated random forest regression kriging). The estimated uncertainty will be calculated to assess the model performance at different scale approaches. Organic carbon modelling of aerial biomass will be estimate using LiDAR (Light Detection And Ranging

  17. Exploring industry specific social welfare maximizing rates of water pollution abatement in linked terrestrial and marine ecosystems

    NARCIS (Netherlands)

    Roebeling, P.C.; Hendrix, E.M.T.; Grieken, van M.E.

    2009-01-01

    Marine ecosystems are severely affected by water pollution originating from coastal catchments, while these ecosystems are of vital importance from an environmental as well as an economic perspective. To warrant sustainable economic development of coastal regions, we need to balance the marginal

  18. Isotopic tracers for net primary productivity for a terrestrial ecosystem: a case study of the Volta River basin

    International Nuclear Information System (INIS)

    Hayford, E.K.; Odamtten, G.T.; Enu-Kwesi, L.

    2006-01-01

    The coupling effect of vapour release and CO2 uptake during photosynthesis plays an important role in the carbon and hydrologic cycles. The water use efficiency (WUE) for transpiration was used in calculating the net primary productivity (NPP) for terrestrial ecosystem. Three parameters were used in calculating the water and carbon balance of the River Volta watershed. These are 1) stable isotopes of hydrogen and oxygen, 2) long-term data on precipitation and evapotranspiration, and 3) stoichiometric relations of water and carbon. Results indicate that soils in the watershed annually respire 0.199 Pg C, and that the NPP is +0.029 Pg C yr-1. This implies an annual change in CO2 to the atmosphere within the watershed. Annually, River Volta watershed receives about 380 km3 of rainfall; approximately 50 per cent of which is returned to the atmosphere through plant transpiration. Associated with annual transpiration flux is a carbon flux of 0.170 x 1015 g C yr-1 or 428 g C m-2 yr-1 from the terrestrial ecosystem. Modeled estimates of heterotrophic soil respiration exceeds slightly the estimated NPP values, implying that carbon flux to and from the Volta river watershed is close to being in balance. In other words, the watershed releases annually more carbon dioxide to the atmosphere than it takes. Apart from the terrestrial carbon flux, the balance of photosynthesis and respiration in the Volta lake was also examined. The lake was found to release carbon dioxide to the atmosphere although the magnitude of the flux is smaller than that of the terrestrial ecosystem. (au)

  19. Modeling coupled interactions of carbon, water, and ozone exchange between terrestrial ecosystems and the atmosphere. I: Model description

    International Nuclear Information System (INIS)

    Nikolov, Ned; Zeller, Karl F.

    2003-01-01

    A new biophysical model (FORFLUX) is presented to link ozone deposition with carbon and water cycles in terrestrial ecosystems. - A new biophysical model (FORFLUX) is presented to study the simultaneous exchange of ozone, carbon dioxide, and water vapor between terrestrial ecosystems and the atmosphere. The model mechanistically couples all major processes controlling ecosystem flows trace gases and water implementing recent concepts in plant eco-physiology, micrometeorology, and soil hydrology. FORFLUX consists of four interconnected modules-a leaf photosynthesis model, a canopy flux model, a soil heat-, water- and CO 2 - transport model, and a snow pack model. Photosynthesis, water-vapor flux and ozone uptake at the leaf level are computed by the LEAFC3 sub-model. The canopy module scales leaf responses to a stand level by numerical integration of the LEAFC3 model over canopy leaf area index (LAI). The integration takes into account (1) radiative transfer inside the canopy, (2) variation of foliage photosynthetic capacity with canopy depth, (3) wind speed attenuation throughout the canopy, and (4) rainfall interception by foliage elements. The soil module uses principles of the diffusion theory to predict temperature and moisture dynamics within the soil column, evaporation, and CO 2 efflux from soil. The effect of soil heterogeneity on field-scale fluxes is simulated employing the Bresler-Dagan stochastic concept. The accumulation and melt of snow on the ground is predicted using an explicit energy balance approach. Ozone deposition is modeled as a sum of three fluxes- ozone uptake via plant stomata, deposition to non-transpiring plant surfaces, and ozone flux into the ground. All biophysical interactions are computed hourly while model projections are made at either hourly or daily time step. FORFLUX represents a comprehensive approach to studying ozone deposition and its link to carbon and water cycles in terrestrial ecosystems

  20. Removal of terrestrial DOC in aquatic ecosystems of a temperate river network

    Science.gov (United States)

    Wollheim, W.M.; Stewart, R. J.; Aiken, George R.; Butler, Kenna D.; Morse, Nathaniel B.; Salisbury, J.

    2015-01-01

    Surface waters play a potentially important role in the global carbon balance. Dissolved organic carbon (DOC) fluxes are a major transfer of terrestrial carbon to river systems, and the fate of DOC in aquatic systems is poorly constrained. We used a unique combination of spatially distributed sampling of three DOC fractions throughout a river network and modeling to quantify the net removal of terrestrial DOC during a summer base flow period. We found that aquatic reactivity of terrestrial DOC leading to net loss is low, closer to conservative chloride than to reactive nitrogen. Net removal occurred mainly from the hydrophobic organic acid fraction, while hydrophilic and transphilic acids showed no net change, indicating that partitioning of bulk DOC into different fractions is critical for understanding terrestrial DOC removal. These findings suggest that river systems may have only a modest ability to alter the amounts of terrestrial DOC delivered to coastal zones.

  1. Information indices as a tool for quantifying development of below-ground terrestrial ecosystems

    NARCIS (Netherlands)

    Holtkamp, R.; Tobor-Kaplon, M.A.

    2007-01-01

    Information indices from ecosystem network analysis (ENA) describe the size and organization of an ecosystem and are claimed to quantify ecosystem development [Ulanowicz, R.E., 1986, Growth and Development, Springler-Verslag, New York, 203 pp.]. To date, these indices were not used to describe a

  2. Possible Cretaceous Arctic terrestrial ecosystem dynamics based on a rich dinosaur record from Alaska

    Science.gov (United States)

    Fiorillo, A. R.; McCarthy, P. J.; Flaig, P. P.

    2010-12-01

    The widespread occurrence of large-bodied herbivores, specifically hadrosaurian and ceratopsian dinosaurs, in the Cretaceous of Alaska presents a proxy for understanding polar terrestrial ecosystem biological productivity in a warm Arctic world. These dinosaurs lived in Alaska at time when this region was at or near current latitudes. Thus these dinosaurs present a paradox. The warmer Cretaceous high-latitude climate, likely related to higher levels of CO2, may have increased plant productivity but the polar light regime fluctuations must have limited the available food during the winter months. The most detailed sedimentological data available regarding the paleoenvironments supporting these dinosaurs are from the Prince Creek Formation of northern Alaska and to a lesser extent the Cantwell Formation of the Alaska Range. The sediments of the Late Cretaceous Prince Creek Formation represent a continental succession deposited on a high-latitude, low-gradient, alluvial/coastal plain. The Prince Creek Formation records numerous paleosols that are consistent with seasonality and successional vegetative cover. Drab colors in fine-grained sediments, abundant carbonaceous plant material, and common siderite nodules and jarosite suggest widespread reducing conditions on poorly-drained floodplains influenced in more distal areas by marine waters. In addition, these rocks contain high levels of organic carbon and charcoal. Carbonaceous root-traces found ubiquitously within all distributary channels and most floodplain facies, along with common Fe-oxide mottles, indicate that the alluvial system likely experienced flashy, seasonal, or ephemeral flow and a fluctuating water table. The flashy nature of the alluvial system may have been driven by recurring episodes of vigorous seasonal snowmelt in the Brooks Range orogenic belt as a consequence of the high paleolatitude of northern Alaska in the Late Cretaceous. The presence of dinosaurian megaherbivores suggests that water was

  3. Scale dependence of absorption of photosynthetically active radiation in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Asner, G.P.; Wessman, C.A.; Archer, S.

    1998-01-01

    The fraction of photosynthetically active radiation absorbed by plant canopies (fAPAR) is a critical biophysical variable for extrapolating ecophysiological measurements from the leaf to landscape scale. Quantification of fAPAR determinants at the landscape level is needed to improve the interpretation of remote sensing data, to facilitate its use in constraining ecosystem process models, and to improve synoptic-scale links between carbon and nutrient cycles. Most canopy radiation budget studies have focused on light attenuation in plant canopies, with little regard for the importance of the scale-dependent biophysical and structural factors (e.g., leaf and stem optical properties, leaf and stem area, and extent of vegetation structural types) that ultimately determine fAPAR at canopy and landscape scales. Most studies have also assumed that nonphotosynthetic vegetation (litter and stems) contributes little to fAPAR. Using a combined field measurement and radiative transfer modeling approach, we quantified (a) the relative role of the leaf-, canopy-, and landscape-level factors that determine fAPAR in terrestrial ecosystems and (b) the magnitude of PAR absorption by grass litter and woody plant stems. Variability in full spectral-range (400–2500 nm) reflectance/transmittance and PAR (400–700 nm) absorption at the level of individual leaf, stem, and litter samples was quantified for a wide array of broadleaf arborescent and grass species along a 900-km north–south Texas savanna transect. Among woody growth forms, leaf reflectance and transmittance spectra were statistically comparable between populations, species within a genus, and functional types (deciduous vs. evergreen, legume vs. nonlegume). Within the grass life-form, spectral properties were statistically comparable between species and C 3 /C 4 physiologies. We found that tissue-level PAR absorption among species, genera, functional groups, and growth forms and between climatologically diverse regions

  4. Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

    Science.gov (United States)

    Walters, D.M.; Mills, M.A.; Fritz, K.M.; Raikow, D.F.

    2010-01-01

    We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell Superfund site (Clemson, SC). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upland spiders (Araneidae) along a sediment contamination gradient. Stable isotopes (?13C, ? 15N) indicated that riparian spiders primarily consumed aquatic insects whereas upland spiders consumed terrestrial insects. PCBs in chironomids (mean 1240 ng/g among sites) were 2 orders of magnitude higher than terrestrial insects (15.2 ng/g), similar to differences between riparian (820?2012 ng/g) and upland spiders (30 ng/g). Riparian spider PCBs were positively correlated with sediment concentrations for all taxa (r2 = 0.44?0.87). We calculated spider-based wildlife values (WVs, the minimum spider PCB concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Spider concentrations exceeded WVs for most birds at heavily contaminated sites and were ?14-fold higher for the most sensitive species (chickadee nestlings, Poecile spp.). Spiders are abundant and ubiquitous in riparian habitats, where they depend on aquatic insect prey. These traits, along with the high degree of spatial correlation between spider and sediment concentrations we observed, suggest that they are model indicator species for monitoring contaminated sediment sites and assessing risks associated with contaminant flux into terrestrial ecosystems. ?? This article not subject to U.S. Copyright. Published 2009 by the American Chemical Society.

  5. Drought-induced vegetation shifts in terrestrial ecosystems: The key role of regeneration dynamics

    Science.gov (United States)

    Martínez-Vilalta, Jordi; Lloret, Francisco

    2016-09-01

    Ongoing climate change is modifying climatic conditions worldwide, with a trend towards drier conditions in most regions. Vegetation will respond to these changes, eventually adjusting to the new climate. It is unclear, however, how close different ecosystems are to climate-related tipping points and, thus, how dramatic these vegetation changes will be in the short- to mid-term, given the existence of strong stabilizing processes. Here, we review the published evidence for recent drought-induced vegetation shifts worldwide, addressing the following questions: (i) what are the necessary conditions for vegetation shifts to occur? (ii) How much evidence of drought-induced vegetation shifts do we have at present and where are they occurring? (iii) What are the main processes that favor/oppose the occurrence of shifts at different ecological scales? (iv) What are the complications in detecting and attributing drought-induced vegetation shifts? (v) What ecological factors can interact with drought to promote shifts or stability? We propose a demographic framework to classify the likely outcome of instances of drought-induced mortality, based upon the survival of adults of potential replacement species and the regeneration of both formerly dominant affected species and potential replacement species. Out of 35 selected case studies only eight were clearly consistent with the occurrence of a vegetation shift (species or biome shift), whereas three corresponded to self-replacements in which the affected, formerly dominant species was able to regenerate after suffering drought-induced mortality. The other 24 cases were classified as uncertain, either due to lack of information or, more commonly, because the initially affected and potential replacement species all showed similar levels of regeneration after the mortality event. Overall, potential vegetation transitions were consistent with more drought-resistant species replacing less resistant ones. However, almost half (44

  6. Drought dominates the interannual variability in global terrestrial net primary production by controlling semi-arid ecosystems.

    Science.gov (United States)

    Huang, Ling; He, Bin; Chen, Aifang; Wang, Haiyan; Liu, Junjie; Lű, Aifeng; Chen, Ziyue

    2016-04-19

    Drought is a main driver of interannual variation in global terrestrial net primary production. However, how and to what extent drought impacts global NPP variability is unclear. Based on the multi-timescale drought index SPEI and a satellite-based annual global terrestrial NPP dataset, we observed a robust relationship between drought and NPP in both hemispheres. In the Northern Hemisphere, the annual NPP trend is driven by 19-month drought variation, whereas that in the Southern Hemisphere is driven by 16-month drought variation. Drought-dominated NPP, which mainly occurs in semi-arid ecosystems, explains 29% of the interannual variation in global NPP, despite its 16% contribution to total global NPP. More surprisingly, drought prone ecosystems in the Southern Hemisphere, which only account for 7% of the total global NPP, contribute to 33% of the interannual variation in global NPP. Our observations support the leading role of semi-arid ecosystems in interannual variability in global NPP and highlight the great impacts of long-term drought on the global carbon cycle.

  7. Radionuclides in the terrestrial ecosystem near a Canadian uranium mill -- Part 2: Small mammal food chains and bioavailability

    International Nuclear Information System (INIS)

    Thomas, P.A.

    2000-01-01

    Food chain transfer through the soil-vegetation-small mammal food chain was measured by concentration ratios (CRs) for uranium, 226 Ra, 210 Pb, and 210 Po at three sites near the Key Lake uranium mill in northern Saskatchewan. Plant/soil CRs, animal carcass/GI tract CRs, and animal/soil CRs were depressed at sites impacted by mill and tailings dusts relative to a nearby control site. Thus, radionuclides associated with large particulates in tailings and/or ore dusts may be less bioavailable to terrestrial plants and animals than natural sources of radioactive dust. These results show that reliance on default food chain transfer parameters, obtained from uncontaminated terrestrial ecosystems, may overpredict impacts at uranium mine and mill sites. Given the omnivorous diet of small mammals and birds, animal/soil CRs are recommended as the most cost-effective and robust means of predicting animal concentrations from environmental monitoring data at uranium mill facilities

  8. Early Cretaceous terrestrial ecosystems in East Asia based on food-web and energy-flow models

    Science.gov (United States)

    Matsukawa, M.; Saiki, K.; Ito, M.; Obata, I.; Nichols, D.J.; Lockley, M.G.; Kukihara, R.; Shibata, K.

    2006-01-01

    In recent years, there has been global interest in the environments and ecosystems around the world. It is helpful to reconstruct past environments and ecosystems to help understand them in the present and the future. The present environments and ecosystems are an evolving continuum with those of the past and the future. This paper demonstrates the contribution of geology and paleontology to such continua. Using fossils, we can make an estimation of past population density as an ecosystem index based on food-web and energy-flow models. Late Mesozoic nonmarine deposits are distributed widely on the eastern Asian continent and contain various kinds of fossils such as fishes, amphibians, reptiles, dinosaurs, mammals, bivalves, gastropods, insects, ostracodes, conchostracans, terrestrial plants, and others. These fossil organisms are useful for late Mesozoic terrestrial ecosystem reconstruction using food-web and energy-flow models. We chose Early Cretaceous fluvio-lacustrine basins in the Choyr area, southeastern Mongolia, and the Tetori area, Japan, for these analyses and as a potential model for reconstruction of other similar basins in East Asia. The food-web models are restored based on taxa that occurred in these basins. They form four or five trophic levels in an energy pyramid consisting of rich primary producers at its base and smaller biotas higher in the food web. This is the general energy pyramid of a typical ecosystem. Concerning the population densities of vertebrate taxa in 1 km2 in these basins, some differences are recognized between Early Cretaceous and the present. For example, Cretaceous estimates suggest 2.3 to 4.8 times as many herbivores and 26.0 to 105.5 times the carnivore population. These differences are useful for the evaluation of past population densities of vertebrate taxa. Such differences may also be caused by the different metabolism of different taxa. Preservation may also be a factor, and we recognize that various problems occur in

  9. Biome-BGC: Terrestrial Ecosystem Process Model, Version 4.1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — Biome-BGC is a computer program that estimates fluxes and storage of energy, water, carbon, and nitrogen for the vegetation and soil components of terrestrial...

  10. El Niño effects on the dynamics of terrestrial ecosystems.

    Science.gov (United States)

    Holmgren, M; Scheffer, M; Ezcurra, E; Gutiérrez, J R.; Mohren, G M.J.

    2001-02-01

    New studies are showing that the El Niño Southern Oscillation (ENSO) has major implications for the functioning of different ecosystems, ranging from deserts to tropical rain forests. ENSO-induced pulses of enhanced plant productivity can cascade upward through the food web invoking unforeseen feedbacks, and can cause open dryland ecosystems to shift to permanent woodlands. These insights suggest that the predicted change in extreme climatic events resulting from global warming could profoundly alter biodiversity and ecosystem functioning in many regions of the world. Our increasing ability to predict El Niño effects can be used to enhance management strategies for the restoration of degraded ecosystems.

  11. Net Carbon Dioxide and Water Fluxes of Global Terrestrial Ecosystems, 1969-1998

    Data.gov (United States)

    National Aeronautics and Space Administration — The variability of net surface carbon assimilation (Asmax), net ecosystem surface respiration (Rsmax), and net surface evapotranspiration (Etsmax) among and within...

  12. A model using marginal efficiency of investment to analyse carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)

    Science.gov (United States)

    Thomas, R. Q.; Williams, M.

    2014-04-01

    Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System modelling community. However there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C-N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) using emergent constraints provided by marginal returns on investment for C and/or N allocation. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. Also, a widely used linear leaf N-respiration relationship did not yield a realistic leaf C : N, while a more recently reported non-linear relationship performed better. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C, GPP, and NPP

  13. Flooding Duration Affects the Structure of Terrestrial and Aquatic Microbial Eukaryotic Communities.

    Science.gov (United States)

    Röhl, Oliver; Graupner, Nadine; Peršoh, Derek; Kemler, Martin; Mittelbach, Moritz; Boenigk, Jens; Begerow, Dominik

    2017-10-12

    The increasing number and duration of inundations is reported to be a consequence of climate change and may severely compromise non-adapted macroorganisms. The effect of flooding events on terrestrial and aquatic microbial communities is, however, less well understood. They may respond to the changed abiotic properties of their native habitat, and the native community may change due to the introduction of alien species. We designed an experiment to investigate the effect of five different flooding durations on the terrestrial and aquatic communities of eukaryotic microorganism, using the AquaFlow mesocosms. With amplicon sequencing of the small subunit (SSU) and internal transcribed spacer (ITS) rRNA gene regions, we analyzed community compositions directly before and after flooding. Subsequently, they were monitored for another 28 days, to determine the sustainability of community changes. Our results revealed a temporary increase in similarity between terrestrial and aquatic communities according to OTU composition (operational taxonomic unit, serves as a proxy for species). Increased similarity was mainly caused by the transmission of OTUs from water to soil. A minority of these were able to persist in soil until the end of the experiment. By contrast, the vast majority of soil OTUs was not transmitted to water. Flooding duration affected the community structure (abundance) more than composition (occurrence). Terrestrial communities responded immediately to flooding and the flooding duration influenced the community changes. Independent from flooding duration, all terrestrial communities recovered largely after flooding, indicating a remarkable resilience to the applied disturbances. Aquatic communities responded immediately to the applied inundations too. At the end of the experiment, they grouped according to the applied flooding duration and the amount of ammonium and chloride that leached from the soil. This indicates a sustained long-term response of the

  14. Comprehensive Evaluation of Machine Learning Techniques for Estimating the Responses of Carbon Fluxes to Climatic Forces in Different Terrestrial Ecosystems

    Directory of Open Access Journals (Sweden)

    Xianming Dou

    2018-02-01

    Full Text Available Accurately estimating the carbon budgets in terrestrial ecosystems ranging from flux towers to regional or global scales is particularly crucial for diagnosing past and future climate change. This research investigated the feasibility of two comparatively advanced machine learning approaches, namely adaptive neuro-fuzzy inference system (ANFIS and extreme learning machine (ELM, for reproducing terrestrial carbon fluxes in five different types of ecosystems. Traditional artificial neural network (ANN and support vector machine (SVM models were also utilized as reliable benchmarks to measure the generalization ability of these models according to the following statistical metrics: coefficient of determination (R2, index of agreement (IA, root mean square error (RMSE, and mean absolute error (MAE. In addition, we attempted to explore the responses of all methods to their corresponding intrinsic parameters in terms of the generalization performance. It was found that both the newly proposed ELM and ANFIS models achieved highly satisfactory estimates and were comparable to the ANN and SVM models. The modeling ability of each approach depended upon their respective internal parameters. For example, the SVM model with the radial basis kernel function produced the most accurate estimates and performed substantially better than the SVM models with the polynomial and sigmoid functions. Furthermore, a remarkable difference was found in the estimated accuracy among different carbon fluxes. Specifically, in the forest ecosystem (CA-Obs site, the optimal ANN model obtained slightly higher performance for gross primary productivity, with R2 = 0.9622, IA = 0.9836, RMSE = 0.6548 g C m−2 day−1, and MAE = 0.4220 g C m−2 day−1, compared with, respectively, 0.9554, 0.9845, 0.4280 g C m−2 day−1, and 0.2944 g C m−2 day−1 for ecosystem respiration and 0.8292, 0.9306, 0.6165 g C m−2 day−1, and 0.4407 g C m−2 day−1 for net ecosystem exchange

  15. Spatial distribution of caesium-137 in soil cover of background terrestrial ecosystems, Central European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Paramonova, Tatiana A. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation); Shamshurina, Evgenia N. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation)

    2014-07-01

    ¹³⁷Cs - the main long-living anthropogenic radionuclide - arrived in mass at Russian terrestrial ecosystems after nuclear tests in the atmosphere in 1960-yy. and after Chernobyl accident in 1986 y., but in spite of a long period since these events soil cover contamination by ¹³⁷Cs is considered as extremely resistant due to its firmly fixation by soil solid matter and a long half-life of the radionuclide. Wide-scale investigation in maximal diversity of natural, semi-natural and anthropogenic landscapes of Central European Russia (more than 400 soils samples from Vologda, Yaroslavl, Ivanovo, Tver regions which are representative for the southern taiga zone) demonstrates that modern average specific activity of ¹³⁷Cs in the upper 15-cm layer of soil is 11±3 Bq/kg (contamination density 0.05±0.01 Ci/km²), that is fully ecologically acceptable. It is important that the average concentrations of ¹³⁷Cs in the soil cover of individual regions are close to each other. The most likely these average values are approximate assessment of background radioactive contamination of soils in central European Russia outside of the immediate Chernobyl trace. At the same time approximately 3% of soils are characterized by elevated ¹³⁷Cs content - 62-98 Bq/kg (0.24-0.43 Ci/km²), that indicates the presence of low radioactive spots on the territory and may be considered as local Chernobyl fallout. All of them attribute with forest soils which are commonly characterized by considerably more high accumulation of ¹³⁷Cs (18±5 Bq/kg, 0.06±0.01 Ci/km²) due to advanced absorbing surface of trees. Agricultural lands (plagued or under meadows) and soils of industrial plots with scarce vegetation contain only 6±2 Bq/kg (0.03±0.01 Ci/km²) of ¹³⁷Cs. About 84-92% of ¹³⁷Cs are concentrated in the upper 15-cm layer of natural soils or in Ap horizon of plagued soils, thus vertical migration of radionuclide is very slow in spite of ~30 years after Chernobyl

  16. Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats

    NARCIS (Netherlands)

    Stevens, C.J.; Manning, P.; Berg, van den L.J.L.; Graaf, de M.C.C.; Wamelink, G.W.W.; Boxman, A.W.; Bleeker, A.; Vergeer, P.; Arroniz-Crespo, M.; Limpens, J.; Lamers, L.P.M.; Bobbink, R.; Dorland, E.

    2011-01-01

    While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NHx and NOy) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and

  17. Mapping and Quantifying Biodiversity and Ecosystem Services Related to Terrestrial Vertebrates: A National Approach

    Science.gov (United States)

    Biodiversity is crucial for the functioning of ecosystems and the products and services from which we transform natural assets of the Earth for human survival, security, and well-being. The ability to assess, report, map, and forecast the life support functions of ecosystems is a...

  18. Risk assessment for human health and terrestrial ecosystem under chronic radioactive pollution near regional radioactive waste storage

    Science.gov (United States)

    Lavrentyeva, G. V.; Katkova, M. N.; Shoshina, R. R.; Synzynys, B. I.

    2017-01-01

    An impact of the radioactive waste storage facility at the regional population was assessed under supervision of IAEA. It was made in accordance with the methodology for assessment of doses and risks to human storage using different scenarios of radionuclides releases into the environment. The following scenarios were considered: leakage of fluid, resuspension of dust, fire, flooding. Thy evaluation of radiation doses received and the risks to the human showed that the risk has been acceptable for all scenarios. An approach for an ecological risk assessment for terrestrial ecosystem is presented as five modules: selection of the ecosystem-receptor of radiation effects; determination of reference species of living organisms and their survival indices; the critical load as an absorbed dose rate is calculated from the dependence between the absorbed Sr-90 radiation dose rate and the coefficient of radioactive strontium accumulation in mollusc shells; the critical dose; risk is assessed from a part of the ecosystem territory with increased mollusc loading; uncertainties appeared at each stage of risk assessment are characterized. The risk of exposure to the repository on the ecosystem should be characterized as unacceptable.

  19. Impacts of 1.5 °C versus 2 °C Warming on Terrestrial Ecosystems in China

    Science.gov (United States)

    Shi, H.; Tian, H.; Yang, J.; Pan, S.; Ouyang, Z.; Fu, B.; Reyer, C.

    2017-12-01

    An average 2 °C increase of global temperature compared to the pre-industrial times has been set as a long-term goal in climate change negotiations since 2009. However, there are intensive debates whether such a level of global warming can prevent excessive anthropogenic influence on the climate system and thus ecosystems. Such concerns arise from the spatial heterogeneity of global warming and ecosystem stability. For example, arid and semi-arid regions experienced the fastest warming in recent decades, while the ecosystems in these regions are extremely vulnerable to climate change. Therefore, a target of a temperature increase of 1.5 °C has gained more and more attention. Here, we compared the potential benefits of 1.5 °C and 2 °C warming for terrestrial ecosystems in China, based on the The Inter-Sectoral Impact Model Intercomparison Project (ISIMIP). Carbon and water outputs by ISIMIP biomes models under two warming scenarios (RCP2.6 and RCP6.0) were analyzed among different plant function types and hydroclimatic conditions. Our study provides solid scientific knowledge for policy making to mitigate global warming.

  20. Risk assessment for human health and terrestrial ecosystem under chronic radioactive pollution near regional radioactive waste storage

    International Nuclear Information System (INIS)

    Lavrentyeva, G V; Katkova, M N; Shoshina, R R; Synzynys, B I

    2017-01-01

    An impact of the radioactive waste storage facility at the regional population was assessed under supervision of IAEA. It was made in accordance with the methodology for assessment of doses and risks to human storage using different scenarios of radionuclides releases into the environment. The following scenarios were considered: leakage of fluid, resuspension of dust, fire, flooding. Thy evaluation of radiation doses received and the risks to the human showed that the risk has been acceptable for all scenarios. An approach for an ecological risk assessment for terrestrial ecosystem is presented as five modules: selection of the ecosystem-receptor of radiation effects; determination of reference species of living organisms and their survival indices; the critical load as an absorbed dose rate is calculated from the dependence between the absorbed Sr-90 radiation dose rate and the coefficient of radioactive strontium accumulation in mollusc shells; the critical dose; risk is assessed from a part of the ecosystem territory with increased mollusc loading; uncertainties appeared at each stage of risk assessment are characterized. The risk of exposure to the repository on the ecosystem should be characterized as unacceptable. (paper)

  1. Changes of evapotranspiration and water yield in China's terrestrial ecosystems during the period from 2000 to 2010

    Science.gov (United States)

    Liu, Y.; Zhou, Y.; Ju, W.; Chen, J.; Wang, S.; He, H.; Wang, H.; Guan, D.; Zhao, F.; Li, Y.; Hao, Y.

    2013-04-01

    Terrestrial carbon and water cycles are interactively linked at various spatial and temporal scales. Evapotranspiration (ET) plays a key role in the terrestrial water cycle and altering carbon sequestration of terrestrial ecosystems. The study of ET and its response to climate and vegetation changes is critical in China since water availability is a limiting factor for the functioning of terrestrial ecosystems in vast arid and semiarid regions. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model was employed in conjunction with a newly developed leaf area index (LAI) dataset and other spatial data to simulate daily ET and water yield at a spatial resolution of 500 m over China for the period from 2000 to 2010. The spatial and temporal variations of ET and water yield and influences of temperature, precipitation, land cover types, and LAI on ET were analyzed. The validations with ET measured at 5 typical ChinaFLUX sites and inferred using statistical hydrological data in 10 basins showed that the BEPS model was able to simulate daily and annual ET well at site and basin scales. Simulated annual ET exhibited a distinguishable southeast to northwest decreasing gradient, corresponding to climate conditions and vegetation types. It increased with the increase of LAI in 74% of China's landmass and was positively correlated with temperature in most areas of southwest, south, east, and central China and with precipitation in the arid and semiarid areas of northwest and north China. In the Tibet Plateau and humid southeast China, the increase in precipitation might cause ET to decrease. The national mean annual ET varied from 345.5 mm yr-1 in 2001 to 387.8 mm yr-1 in 2005, with an average of 369.8 mm yr-1 during the study period. The overall increase rate of 1.7 mm yr-2 (r = 0.43 p = 0.19) was mainly driven by the increase of total ET in forests. During the period from 2006 to 2009, precipitation and LAI decreased widely and consequently

  2. Global Trends in Exposure to Light Pollution in Natural Terrestrial Ecosystems

    Directory of Open Access Journals (Sweden)

    Jonathan Bennie

    2015-03-01

    Full Text Available The rapid growth in electric light usage across the globe has led to increasing presence of artificial light in natural and semi-natural ecosystems at night. This occurs both due to direct illumination and skyglow - scattered light in the atmosphere. There is increasing concern about the effects of artificial light on biological processes, biodiversity and the functioning of ecosystems. We combine intercalibrated Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS images of stable night-time lights for the period 1992 to 2012 with a remotely sensed landcover product (GLC2000 to assess recent changes in exposure to artificial light at night in 43 global ecosystem types. We find that Mediterranean-climate ecosystems have experienced the greatest increases in exposure, followed by temperate ecosystems. Boreal, Arctic and montane systems experienced the lowest increases. In tropical and subtropical regions, the greatest increases are in mangroves and subtropical needleleaf and mixed forests, and in arid regions increases are mainly in forest and agricultural areas. The global ecosystems experiencing the greatest increase in exposure to artificial light are already localized and fragmented, and often of particular conservation importance due to high levels of diversity, endemism and rarity. Night time remote sensing can play a key role in identifying the extent to which natural ecosystems are exposed to light pollution.

  3. Restoration of Degraded Salt Affected Lands to Productive Forest Ecosystem

    Science.gov (United States)

    Singh, Yash; Singh, Gurbachan; Singh, Bajrang; Cerdà, Artemi

    2017-04-01

    Soil system determines the fluxes of energy and matter in the Earth and is the source of goods, services and resources to the humankind (Keesstra et al., 2012; Brevik et al., 2015; Keesstra et al., 2016). To restore and rehabilitate the soil system is a key strategy to recover the services the soils offers (Celentano et al., 2016; Galati et al., 2016; Parras-Alcantara et al., 2016). Transformation of degraded sodic lands in biodiversity rich productive forest ecosystem is a challenging task before the researchers all over the world. The soils of the degraded sites remain almost unfavorable for the normal growth, development and multiplication of organisms; all our attempts tend to alleviate the soil constraints. Land degradation due to presence of salts in the soil is an alarming threat to agricultural productivity and sustainability, particularly in arid and semiarid regions of the world (Tanji, 1990; Qadir et al., 2006). According to the FAO Land and Nutrition Management Service (2008), over 6% of the world's lands are affected by salinity, which accounts for more than 800 million ha in 100 countries. This is due to natural causes, extensive utilization of land (Egamberdieva et al., 2008), poor drainage systems and limited availability of irrigation water which causes salinization in many irrigated soils (Town et al., 2008).In India, about 6.73 million ha are salt affected which spread in 194 districts out of 584 districts in India and represents 2.1% of the geographical area of the country (Mandal et al., 2009).Out of these, 2.8 million ha are sodic in nature and primarily occurring in the Indo-Gangetic alluvial plains. These lands are degraded in structural, chemical, nutritional, hydrological and microbiological characteristics. The reclamation of salt affected soils with chemical amendments like gypsum and phospho-gypsum are in practice for the cultivation field crops under agricultural production. Forest development on such lands although takes considerable

  4. The influence of competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0

    Science.gov (United States)

    Melton, Joe; Arora, Vivek

    2015-04-01

    The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component in the earth system modelling framework of the Canadian Centre for Climate Modelling and Analysis (CCCma). In its current framework, CTEM uses prescribed fractional coverage of plant functional types (PFTs) in each grid cell. In reality, vegetation cover is continually adjusting to changes in climate, atmospheric composition, and anthropogenic forcing, for example, through human-caused fires and CO2 fertilization. These changes in vegetation spatial patterns occur over timescales of years to centuries as tree migration is a slow process and vegetation distributions inherently have inertia. Here, we present version 2.0 of CTEM that includes a representation of competition between PFTs through a modified version of the Lotka-Volterra (L-V) predator-prey equations. The simulated areal extents of CTEM's seven non-crop PFTs are compared with available observation-based estimates, and simulations using unmodified L-V equations (similar to other models like TRIFFID), to demonstrate that the model is able to represent the broad spatial distributions of its seven PFTs at the global scale. Differences remain, however, since representing the multitude of plant species with just seven non-crop PFTs only allows the large scale climatic controls on the distributions of PFTs to be captured. As expected, PFTs that exist in climate niches are difficult to represent either due to the coarse spatial resolution of the model and the corresponding driving climate or the limited number of PFTs used to model the terrestrial ecosystem processes. The geographic and zonal distributions of primary terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and dynamically simulated fractional coverage of PFTs compare reasonably with each other and observation-based estimates. These results illustrate that the parametrization of competition between PFTs in CTEM behaves in a reasonably

  5. Characterisation of perfluorooctane sulfonate (PFOS) in a terrestrial ecosystem near a fluorochemical plant in Flanders, Belgium

    NARCIS (Netherlands)

    D'Hollander, W.; De Bruyn, L.; Hagenaars, A; de Voogt, P.; Bervoets, L.

    2014-01-01

    Bioaccumulation of perfluorooctane sulfonate (PFOS) in a restricted terrestrial food chain was investigated with the omnivorous wood mouse (Apodemus sylvaticus) on top of the studied food chain. The levels detected are very high compared with literature as a result of the presence of fluorochemical

  6. Patterns and controls of the variability of radiation use efficiency and primary productivity across terrestrial ecosystems

    NARCIS (Netherlands)

    Garbulsky, M.F.; Peñuelas, J.; Papale, D.; Ardö, J.; Goulden, M.L.; Kiely, G.; Richardson, A.D.; Rotenberg, E.; Veenendaal, E.M.; Filella, I.

    2010-01-01

    Aim The controls of gross radiation use efficiency (RUE), the ratio between gross primary productivity (GPP) and the radiation intercepted by terrestrial vegetation, and its spatial and temporal variation are not yet fully understood. Our objectives were to analyse and synthesize the spatial

  7. Modeling coupled interactions of carbon, water, and ozone exchange between terrestrial ecosystems and the atmosphere. I: model description.

    Science.gov (United States)

    Nikolov, Ned; Zeller, Karl F

    2003-01-01

    A new biophysical model (FORFLUX) is presented to study the simultaneous exchange of ozone, carbon dioxide, and water vapor between terrestrial ecosystems and the atmosphere. The model mechanistically couples all major processes controlling ecosystem flows trace gases and water implementing recent concepts in plant eco-physiology, micrometeorology, and soil hydrology. FORFLUX consists of four interconnected modules-a leaf photosynthesis model, a canopy flux model, a soil heat-, water- and CO2- transport model, and a snow pack model. Photosynthesis, water-vapor flux and ozone uptake at the leaf level are computed by the LEAFC3 sub-model. The canopy module scales leaf responses to a stand level by numerical integration of the LEAFC3model over canopy leaf area index (LAI). The integration takes into account (1) radiative transfer inside the canopy, (2) variation of foliage photosynthetic capacity with canopy depth, (3) wind speed attenuation throughout the canopy, and (4) rainfall interception by foliage elements. The soil module uses principles of the diffusion theory to predict temperature and moisture dynamics within the soil column, evaporation, and CO2 efflux from soil. The effect of soil heterogeneity on field-scale fluxes is simulated employing the Bresler-Dagan stochastic concept. The accumulation and melt of snow on the ground is predicted using an explicit energy balance approach. Ozone deposition is modeled as a sum of three fluxes- ozone uptake via plant stomata, deposition to non-transpiring plant surfaces, and ozone flux into the ground. All biophysical interactions are computed hourly while model projections are made at either hourly or daily time step. FORFLUX represents a comprehensive approach to studying ozone deposition and its link to carbon and water cycles in terrestrial ecosystems.

  8. Characterization of field margins in intensified agro-ecosystems-why narrow margins should matter in terrestrial pesticide risk assessment and management.

    Science.gov (United States)

    Hahn, Melanie; Lenhardt, Patrick P; Brühl, Carsten A

    2014-07-01

    Field margins are important seminatural habitats in agro-ecosystems, but they can be negatively affected by pesticide inputs via direct overspray and spray drift. In Germany, risk mitigation measures (like buffer zones) to reduce pesticide inputs in terrestrial noncrop habitats do not have to be put in place by farmers next to narrow field margins (Hedgerows were only occasionally recorded. Hence, narrow grassy field margins can represent a large part of the available seminatural habitats adjoining agricultural sites and potentially act as corridors between further habitat patches. For this reason, these margins should be protected from pesticide inputs, at least in landscapes under intensive agricultural use. Field margins are also the main, so-called nontarget habitat protected by the terrestrial risk assessment for plants and arthropods. With many (narrow) margins not considered relevant for risk management, the current practice for protecting the biodiversity from negative effects of pesticides seems questionable. More data on field margin constitution in Germany and other European countries is necessary to critically assess the current practice of pesticide risk assessment and management on a larger scale. © 2014 SETAC.

  9. Developing Conceptual Models for Assessing Climate Change Impacts to Contaminant Availability in Terrestrial Ecosystems

    Science.gov (United States)

    2015-03-01

    Threatened and endangered species (also top-level predators and other keystone species ) • Wetlands • Grassland/Rangeland plant communities • Microbial...aspects of climate change can impact contaminant availability and threatened, endangered, and at-risk species (TER-S) of terrestrial habitats on military...contaminants as well as emerging contaminants (e.g., nanomaterials), and invasive species /pathogens What are the mechanisms by which aspects of climate

  10. Simulated sensitivity of African terrestrial ecosystem photosynthesis to rainfall frequency, intensity, and rainy season length

    Science.gov (United States)

    Guan, Kaiyu; Good, Stephen P.; Caylor, Kelly K.; Medvigy, David; Pan, Ming; Wood, Eric F.; Sato, Hisashi; Biasutti, Michela; Chen, Min; Ahlström, Anders; Xu, Xiangtao

    2018-02-01

    There is growing evidence of ongoing changes in the statistics of intra-seasonal rainfall variability over large parts of the world. Changes in annual total rainfall may arise from shifts, either singly or in a combination, of distinctive intra-seasonal characteristics -i.e. rainfall frequency, rainfall intensity, and rainfall seasonality. Understanding how various ecosystems respond to the changes in intra-seasonal rainfall characteristics is critical for predictions of future biome shifts and ecosystem services under climate change, especially for arid and semi-arid ecosystems. Here, we use an advanced dynamic vegetation model (SEIB-DGVM) coupled with a stochastic rainfall/weather simulator to answer the following question: how does the productivity of ecosystems respond to a given percentage change in the total seasonal rainfall that is realized by varying only one of the three rainfall characteristics (rainfall frequency, intensity, and rainy season length)? We conducted ensemble simulations for continental Africa for a realistic range of changes (-20% ~ +20%) in total rainfall amount. We find that the simulated ecosystem productivity (measured by gross primary production, GPP) shows distinctive responses to the intra-seasonal rainfall characteristics. Specifically, increase in rainfall frequency can lead to 28% more GPP increase than the same percentage increase in rainfall intensity; in tropical woodlands, GPP sensitivity to changes in rainy season length is ~4 times larger than to the same percentage changes in rainfall frequency or intensity. In contrast, shifts in the simulated biome distribution are much less sensitive to intra-seasonal rainfall characteristics than they are to total rainfall amount. Our results reveal three major distinctive productivity responses to seasonal rainfall variability—‘chronic water stress’, ‘acute water stress’ and ‘minimum water stress’ - which are respectively associated with three broad spatial patterns of

  11. Representation of Ecosystem Services by Terrestrial Protected Areas: Chile as a Case Study

    Science.gov (United States)

    Durán, América P.; Casalegno, Stefano; Marquet, Pablo A.; Gaston, Kevin J.

    2013-01-01

    Protected areas are increasingly considered to play a key role in the global maintenance of ecosystem processes and the ecosystem services they provide. It is thus vital to assess the extent to which existing protected area systems represent those services. Here, for the first time, we document the effectiveness of the current Chilean protected area system and its planned extensions in representing both ecosystem services (plant productivity, carbon storage and agricultural production) and biodiversity. Additionally, we evaluate the effectiveness of protected areas based on their respective management objectives. Our results show that existing protected areas in Chile do not contain an unusually high proportion of carbon storage (14.9%), agricultural production (0.2%) or biodiversity (11.8%), and also represent a low level of plant productivity (Normalized Difference Vegetation Index of 0.38). Proposed additional priority sites enhance the representation of ecosystem services and biodiversity, but not sufficiently to attain levels of representation higher than would be expected for their area of coverage. Moreover, when the species groups were assessed separately, amphibians was the only one well represented. Suggested priority sites for biodiversity conservation, without formal protection yet, was the only protected area category that over-represents carbon storage, agricultural production and biodiversity. The low representation of ecosystem services and species’ distribution ranges by the current protected area system is because these protected areas are heavily biased toward southern Chile, and contain large extents of ice and bare rock. The designation and management of proposed priority sites needs to be addressed in order to increase the representation of ecosystem services within the Chilean protected area system. PMID:24376559

  12. How is water-use efficiency of terrestrial ecosystems distributed and changing on Earth?

    DEFF Research Database (Denmark)

    Tang, Xuguang; Li, Hengpeng; Desai, Ankur R.

    2015-01-01

    farther north than 51 degrees N. Finally, long-term spatiotemporal trend analysis using satellite-based remote sensing data reveals that land-cover and land-use change in recent years has led to a decline in global WUE. Our study provides a new framework for global research on the interactions between......A better understanding of ecosystem water-use efficiency (WUE) will help us improve ecosystem management for mitigation as well as adaption to global hydrological change. Here, long-term flux tower observations of productivity and evapotranspiration allow us to detect a consistent latitudinal trend...

  13. Spatial and temporal patterns of CH4 and N2O fluxes in terrestrial ecosystems of North America during 1979–2008: application of a global biogeochemistry model

    Directory of Open Access Journals (Sweden)

    C. Lu

    2010-09-01

    Full Text Available Continental-scale estimations of terrestrial methane (CH4 and nitrous oxide (N2O fluxes over a long time period are crucial to accurately assess the global balance of greenhouse gases and enhance our understanding and prediction of global climate change and terrestrial ecosystem feedbacks. Using a process-based global biogeochemical model, the Dynamic Land Ecosystem Model (DLEM, we quantified simultaneously CH4 and N2O fluxes in North America's terrestrial ecosystems from 1979 to 2008. During the past 30 years, approximately 14.69 ± 1.64 T g C a−1 (1 T g = 1012 g of CH4, and 1.94 ± 0.1 T g N a−1 of N2O were released from terrestrial ecosystems in North America. At the country level, both the US and Canada acted as CH4 sources to the atmosphere, but Mexico mainly oxidized and consumed CH4 from the atmosphere. Wetlands in North America contributed predominantly to the regional CH4 source, while all other ecosystems acted as sinks for atmospheric CH4, of which forests accounted for 36.8%. Regarding N2O emission in North America, the US, Canada, and Mexico contributed 56.19%, 18.23%, and 25.58%, respectively, to the continental source over the past 30 years. Forests and croplands were the two ecosystems that contributed most to continental N2O emission. The inter-annual variations of CH4 and N2O fluxes in North America were mainly attributed to year-to-year climatic variability. While only annual precipitation was found to have a significant effect on annual CH4 flux, both mean annual temperature and annual precipitation were significantly correlated to annual N2O flux. The regional estimates and spatiotemporal patterns of terrestrial ecosystem CH4 and N2O fluxes in North America generated in this study provide useful information for global change research and policy making.

  14. Modelling carbon and water flows in terrestrial ecosystems in the boreal zone - examples from Oskarshamn

    International Nuclear Information System (INIS)

    Karlberg, Louise; Gu stafsson, David; Jansson, Per-Erik

    2007-12-01

    Carbon budgets and mean residence times were estimated in four hypothetical ecosystems. The greatest uncertainties in the estimations lie in the calculation of fluxes to and from the field layer. A parametrisation method based on multiple criteria, synthesising a wide range of empirical knowledge on ecosystem behaviour, proved to be useful both in the estimation of unknown parameters, to demonstrate model sensitivity, and to identify processes where our current knowledge is limited. The parameterizations derived from the study of the hypothetical systems were used to estimate site-specific carbon and water budgets for four ecosystems located within the Oskarshamn study-area. Measured soil respiration was used to calibrate the simulations. An analysis of the simulated carbon fluxes indicated that two of the ecosystems, namely the grassland and the spruce forest, were net sources of carbon dioxide, while the alder and the pine forest were net sinks of CO 2 . In the former case, this was interpreted as a result of recent drainage of the organogenic soils and the concurrent increase in decomposition. The results from the study conformed rather well with results from a previous study on carbon budgets from the Oskarshamn study area

  15. Game animals and small terrestrial mammals - Suitable bioindicators for the pollution assessment in agrarian ecosystems

    Czech Academy of Sciences Publication Activity Database

    Vávrová, M.; Zlámalová Gargošová, H.; Šucman, E.; Večerek, V.; Kořínek, P.; Zukal, Jan; Zejda, Jan; Sebestiánová, N.; Kubištová, I.

    2003-01-01

    Roč. 12, č. 2 (2003), s. 165-172 ISSN 1018-4619 R&D Projects: GA AV ČR KSK6005114 Keywords : bioindicators * agrarian ecosystems * pollution Subject RIV: EH - Ecology, Behaviour Impact factor: 0.325, year: 2003 http://www.psp-parlar.de/details_artikel.asp?tabelle=FEBArtikel&artikel_id=234&jahr=2003

  16. Fluid Dynamics Applied to Streams. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Cowan, Christina E.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module deals specifically with concepts that are basic to fluid flow and…

  17. Transpiration and Leaf Temperature. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Gates, David M.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This report introduces two models of the thermal energy budget of a leaf. Typical values for…

  18. El Niño effects on the dynamics of terrestrial ecosystems

    NARCIS (Netherlands)

    Holmgren, M.; Scheffer, M.; Ezcurra, E.; Gutiérrez, J.R.; Mohren, G.M.J.

    2001-01-01

    New studies are showing that the El Niño Southern Oscillation (ENSO) has major implications for the functioning of different ecosystems, ranging from deserts to tropical rain forests. ENSO-induced pulses of enhanced plant productivity can cascade upward through the food web invoking unforeseen

  19. Thermodynamics of Irreversible Processes. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Levin, Michael; Gallucci, V. F.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module describes the application of irreversible thermodynamics to biology. It begins with…

  20. Climate change impacts on terrestrial ecosystems in metropolitan Chicago and its surrounding, multi-state region

    Science.gov (United States)

    Jessica J. Hellmann; Knute J. Nadelhoffer; Louis R. Iverson; Lewis H. Ziska; Stephen N. Matthews; Philip Myers; Anantha M. Prasad; Matthew P. Peters

    2010-01-01

    This paper describes the potential impacts of warming temperatures and changing precipitation on plants, wildlife, invasive species, pests, and agricultural ecosystems across the multi-state region centered on Chicago, Illinois. We examine a geographic area that captures much of Lake Michigan, including a complex mosaic of urbanization and agriculture surrounding...

  1. Modelling carbon and water flows in terrestrial ecosystems in the boreal zone - examples from Oskarshamn

    Energy Technology Data Exchange (ETDEWEB)

    Karlberg, Louise [Stockholm Environment Institute (SEI), Stockholm (Sweden); Gu stafsson, David; Jansson, Per-Erik [Royal Inst. of Technology, Dept. of Land and Water Resources Engineering, Stockholm (Sweden)

    2007-12-15

    Carbon budgets and mean residence times were estimated in four hypothetical ecosystems. The greatest uncertainties in the estimations lie in the calculation of fluxes to and from the field layer. A parametrisation method based on multiple criteria, synthesising a wide range of empirical knowledge on ecosystem behaviour, proved to be useful both in the estimation of unknown parameters, to demonstrate model sensitivity, and to identify processes where our current knowledge is limited. The parameterizations derived from the study of the hypothetical systems were used to estimate site-specific carbon and water budgets for four ecosystems located within the Oskarshamn study-area. Measured soil respiration was used to calibrate the simulations. An analysis of the simulated carbon fluxes indicated that two of the ecosystems, namely the grassland and the spruce forest, were net sources of carbon dioxide, while the alder and the pine forest were net sinks of CO{sub 2}. In the former case, this was interpreted as a result of recent drainage of the organogenic soils and the concurrent increase in decomposition. The results from the study conformed rather well with results from a previous study on carbon budgets from the Oskarshamn study area.

  2. Trophic disruption: a meta-analysis of how habitat fragmentation affects resource consumption in terrestrial arthropod systems.

    Science.gov (United States)

    Martinson, Holly M; Fagan, William F

    2014-09-01

    Habitat fragmentation is a complex process that affects ecological systems in diverse ways, altering everything from population persistence to ecosystem function. Despite widespread recognition that habitat fragmentation can influence food web interactions, consensus on the factors underlying variation in the impacts of fragmentation across systems remains elusive. In this study, we conduct a systematic review and meta-analysis to quantify the effects of habitat fragmentation and spatial habitat structure on resource consumption in terrestrial arthropod food webs. Across 419 studies, we found a negative overall effect of fragmentation on resource consumption. Variation in effect size was extensive but predictable. Specifically, resource consumption was reduced on small, isolated habitat fragments, higher at patch edges, and neutral with respect to landscape-scale spatial variables. In general, resource consumption increased in fragmented settings for habitat generalist consumers but decreased for specialist consumers. Our study demonstrates widespread disruption of trophic interactions in fragmented habitats and describes variation among studies that is largely predictable based on the ecological traits of the interacting species. We highlight future prospects for understanding how changes in spatial habitat structure may influence trophic modules and food webs. © 2014 John Wiley & Sons Ltd/CNRS.

  3. Oxidation of atmospheric methane in Northern European soils, comparison with other ecosystems, and uncertainties in the global terrestrial sink

    DEFF Research Database (Denmark)

    Smith, K.A.; Dobbie, K.E.; Ball, B.C.

    2000-01-01

    This paper reports the range and statistical distribution of oxidation rates of atmospheric CH4 in soils found in Northern Europe in an international study, and compares them with published data for various other ecosystems. It reassesses the size, and the uncertainty in, the global terrestrial CH4......, with a log-normal distribution (log-mean ˜ 1.6 kg CH4 ha-1 y-1). Conversion of natural soils to agriculture reduced oxidation rates by two-thirds -- closely similar to results reported for other regions. N inputs also decreased oxidation rates. Full recovery of rates after these disturbances takes > 100 y...... to the oxidation. The effect of temperature was small, attributed to substrate limitation and low atmospheric concentration. Analysis of all available data for CH4 oxidation rates in situ showed similar log-normal distributions to those obtained for our results, with generally little difference between different...

  4. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River site

    International Nuclear Information System (INIS)

    Friday, G.P.; Cummins, C.L.; Schwartzman, A.L.

    1996-01-01

    Since the early 1950s, the Savannah River Site (SRS) released over 50 radionuclides into the environment while producing nuclear defense materials. These releases directly exposed aquatic and terrestrial biota to ionizing radiation from surface water, soil, and sediment, and also indirectly by the ingestion of items in the food chain. As part of new missions to develop waste management strategies and identify cost-effective environmental restoration options, knowledge concerning the uptake and distribution of these radionuclides is essential. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at SRS

  5. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River site

    Energy Technology Data Exchange (ETDEWEB)

    Friday, G.P.; Cummins, C.L.; Schwartzman, A.L.

    1996-12-31

    Since the early 1950s, the Savannah River Site (SRS) released over 50 radionuclides into the environment while producing nuclear defense materials. These releases directly exposed aquatic and terrestrial biota to ionizing radiation from surface water, soil, and sediment, and also indirectly by the ingestion of items in the food chain. As part of new missions to develop waste management strategies and identify cost-effective environmental restoration options, knowledge concerning the uptake and distribution of these radionuclides is essential. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at SRS.

  6. Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem

    International Nuclear Information System (INIS)

    Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F.; Morton, O.; Armienta, M.A.; Hernandez, E.

    2001-01-01

    The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

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

    International Nuclear Information System (INIS)

    1995-01-01

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

  8. Impacts of urbanization on carbon balance in terrestrial ecosystems of the Southern United States

    International Nuclear Information System (INIS)

    Zhang Chi; Tian Hanqin; Chen, Guangsheng; Chappelka, Arthur; Xu Xiaofeng; Ren Wei; Hui Dafeng; Liu Mingliang; Lu Chaoqun; Pan, Shufen; Lockaby, Graeme

    2012-01-01

    Using a process-based Dynamic Land Ecosystem Model, we assessed carbon dynamics of urbanized/developed lands in the Southern United States during 1945–2007. The results indicated that approximately 1.72 (1.69–1.77) Pg (1P = 10 15 ) carbon was stored in urban/developed lands, comparable to the storage of shrubland or cropland in the region. Urbanization resulted in a release of 0.21 Pg carbon to the atmosphere during 1945–2007. Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. After a rapid decline of carbon storage during land conversion, an urban ecosystem gradually accumulates carbon and may compensate for the initial carbon loss in 70–100 years. The carbon sequestration rate of urban ecosystem diminishes with time, nearly disappearing in two centuries after land conversion. This study implied that it is important to take urbanization effect into account for assessing regional carbon balance. - Highlights: ► A series of spatial and temporal urban/developed land maps were generated. ► Urbanization effects on regional carbon dynamics were studied with a process-based Dynamic Land Ecosystem Model (DLEM). ► Carbon storage of urban/developed land was comparable to that stored in cropland and shrubland in the Southern United States. ► Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. ► Urbanization resulted in carbon emission, but established urban areas may gradually accumulate carbon over time. - Urbanization has resulted in carbon release to the atmosphere, but established urban areas may gradually accumulate carbon over time.

  9. Reconstructing Ecosystem-Scale Vegetation Activity Across the Terrestrial Mediterranean using Tree-Ring Width Data

    Science.gov (United States)

    Coulthard, B. L.; Touchan, R.; Meko, D. M.; Anchukaitis, K. J.; Sivrikaya, F.; Attalah, S.; Ilmen, R.; Aloui, A.; Attieh, J.; Mitsopoulos, I.; Sabir, M.; Christou, A.; Bozali, N.; Ketmen, M.; Stephan, J.

    2016-12-01

    Connecting radial tree-growth variables with remotely-sensed vegetation indices provides a foundation for using tree-rings as proxies for ecosystem primary productivity over large space and long time scales. Here we explore the association between tree-ring width and Normalized Difference Vegetation Index (NDVI) records across the Mediterranean. In contrast with most previous tree-ring/remote sensing studies, which have focused on temperature-limited boreal and taiga environments, we assess a large network of drought-sensitive tree-ring width chronologies as proxies for ecosystem-scale `greening', which in this region is largely controlled by moisture availability across vegetation cover types. We find that precipitation, elevation, and land-cover type interact to generate a statistical relationship between radial tree growth and NDVI. Specifically, tree-ring chronologies at low-elevation dry sites are strongly correlated with NDVI during the winter (maximum) precipitation season. In these settings land cover is dominated by grass- and shrublands, suggesting tree-ring width operates as a proxy for broader ecosystem-scale vegetation activity as captured by NDVI. Interactions between climate, geography, and land cover modify the extent to which tree-ring data and NDVI are linked across the Mediterranean, and may be capitalized upon to fine-tune spatial reconstructions of vegetation activity here and in other water-limited environments.

  10. Habitats at Risk. Global Warming and Species Loss in Globally Significant Terrestrial Ecosystems

    International Nuclear Information System (INIS)

    Malcolm, J.R.; Liu, Canran; Miller, L.B.; Allnutt, T.; Hansen, L.

    2002-02-01

    In this study, a suite of models of global climate and vegetation change is used to investigate three important global warming-induced threats to the terrestrial Global 200 ecoregions: (1) Invasions by new habitat types (and corresponding loss of original habitat types); (2) Local changes of habitat types; (3) High rates of required species migration. Seven climate models (general circulation models or GCMs) and two vegetation models (BIOME3 and MAPSS) were used to produce 14 impact scenarios under the climate associated with a doubling of atmospheric CO2 concentrations, which is expected to occur in less than 100 years. Previous analyses indicated that most of the variation among the impact scenarios was attributable to the particular vegetation model used, hence the authors provide results separately for the two models. The models do not provide information on biodiversity per se, but instead simulate current and future potential distributions of major vegetation types (biomes) such as tundra and broadleaf tropical rain forest

  11. Effects of long-range transported acidification on the bio-diversity in terrestrial ecosystems; Effekter av langtransporterte forsuringer paa biodiversitet i terrestriske oekosystemer

    Energy Technology Data Exchange (ETDEWEB)

    Hoeiland, K. [Oslo Univ. (Norway)

    1996-01-01

    The conference paper deals with the environmental effects of long-range transported pollutants on the biodiversity in the terrestrial ecosystems. The paper discusses different chemical substances existing in the atmosphere and their influence on vegetation together with the effects on biodiversity from acidification. 4 refs.

  12. How does whole ecosystem warming of a peatland affect methane production and consumption?

    Science.gov (United States)

    Hopple, A.; Brunik, K.; Keller, J.; Pfeifer-Meister, L.; Woerndle, G.; Zalman, C.; Hanson, P.; Bridgham, S. D.

    2017-12-01

    Peatlands are among Earth's most important terrestrial ecosystems due to their massive soil carbon (C) stores and significant release of methane (CH4) into the atmosphere. Methane has a sustained-flux global warming potential 45-times greater than carbon dioxide (CO2), and the accuracy of Earth system model projections relies on our mechanistic understanding of peatland CH4 cycling in the context of environmental change. The objective of this study was to determine, under in situ conditions, how heating of the peat profile affects ecosystem-level anaerobic C cycling. We assessed the response of CO2 and CH4 production, as well as the anaerobic oxidation of CH4 (AOM), in a boreal peatland following 13 months of deep peat heating (DPH) and 16 months of subsequent whole-ecosystem warming (surface and deep heating; WEW) as part of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) project in northern Minnesota, USA. The study uses a regression-based experimental design including 5 temperature treatments that warmed the entire 2 m peat profile from 0 to +9 °C above ambient temperature. Soil cores were collected at multiple depths (25-200 cm) from each experimental chamber at the SPRUCE site and anaerobically incubated at in situ temperatures for 1-2 weeks. Methane and CO2 production in surface peat were positively correlated with elevated temperature, but no consistent temperature response was found at depth (75-200 cm) following DPH. However, during WEW, we observed significant increases in both surface and deep peat methanogenesis with increasing temperature. Surface peat had greater CH4 production rates than deeper peat, implying that the increased CH4 emissions observed in the field were largely driven by surface peat warming. The CO2:CH4 ratio was inversely correlated with temperature across all depths following 16 months of WEW, indicating that the entire peat profile is becoming more methanogenic with warming. We also observed AOM throughout

  13. Optimization of Terrestrial Ecosystem Model Parameters Using Atmospheric CO2 Concentration Data With the Global Carbon Assimilation System (GCAS)

    Science.gov (United States)

    Chen, Zhuoqi; Chen, Jing M.; Zhang, Shupeng; Zheng, Xiaogu; Ju, Weiming; Mo, Gang; Lu, Xiaoliang

    2017-12-01

    The Global Carbon Assimilation System that assimilates ground-based atmospheric CO2 data is used to estimate several key parameters in a terrestrial ecosystem model for the purpose of improving carbon cycle simulation. The optimized parameters are the leaf maximum carboxylation rate at 25°C (Vmax25), the temperature sensitivity of ecosystem respiration (Q10), and the soil carbon pool size. The optimization is performed at the global scale at 1° resolution for the period from 2002 to 2008. The results indicate that vegetation from tropical zones has lower Vmax25 values than vegetation in temperate regions. Relatively high values of Q10 are derived over high/midlatitude regions. Both Vmax25 and Q10 exhibit pronounced seasonal variations at middle-high latitudes. The maxima in Vmax25 occur during growing seasons, while the minima appear during nongrowing seasons. Q10 values decrease with increasing temperature. The seasonal variabilities of Vmax25 and Q10 are larger at higher latitudes. Optimized Vmax25 and Q10 show little seasonal variabilities at tropical regions. The seasonal variabilities of Vmax25 are consistent with the variabilities of LAI for evergreen conifers and broadleaf evergreen forests. Variations in leaf nitrogen and leaf chlorophyll contents may partly explain the variations in Vmax25. The spatial distribution of the total soil carbon pool size after optimization is compared favorably with the gridded Global Soil Data Set for Earth System. The results also suggest that atmospheric CO2 data are a source of information that can be tapped to gain spatially and temporally meaningful information for key ecosystem parameters that are representative at the regional and global scales.

  14. Novel approaches to study climate change effects on terrestrial ecosystems in the field

    DEFF Research Database (Denmark)

    Beier, C.; Emmett, B.; Gundersen, P.

    2004-01-01

    mimicked the way climate change, caused by increased cloudiness and increased greenhouse gas emissions, alters the heat balance of ecosystems. Drought conditions were created by automatically covering the vegetation with transparent curtains during rain events over a 2-5-month period. The experimental...... a valuable tool for investigating the effects of climate change in remote locations with minimal artifacts....... approach has been evaluated at four European sites across a climate gradient. All sites were dominated (more than 50%) by shrubs of the ericaceous family. Within each site, replicated 4-m X 5-m plots were established for control, warming, and drought treatments and the effect on climate variables recorded...

  15. Transfer of radionuclides by terrestrial food products from semi-natural ecosystems to humans

    International Nuclear Information System (INIS)

    Howard, B.J.

    1996-01-01

    The potential radiological significance of radionuclide transfer to humans via foodstuffs derived from semi-natural ecosystems has become apparent since the Chernobyl accident. Foodchain models developed before this time usually did not take such transfers into account. The processes leading to contamination of food in these environments are complex and current understanding of the transfer mechanisms is incomplete. For these reasons the approach adopted in Chapter 3 is to represent, by means of aggregated parameters, the empirical relationships between ground deposits and concentration in the food product. 107 refs, 2 figs, 9 tabs

  16. How is water-use efficiency of terrestrial ecosystems distributed and changing on Earth?

    Science.gov (United States)

    Tang, Xuguang; Li, Hengpeng; Desai, Ankur R; Nagy, Zoltan; Luo, Juhua; Kolb, Thomas E; Olioso, Albert; Xu, Xibao; Yao, Li; Kutsch, Werner; Pilegaard, Kim; Köstner, Barbara; Ammann, Christof

    2014-12-15

    A better understanding of ecosystem water-use efficiency (WUE) will help us improve ecosystem management for mitigation as well as adaption to global hydrological change. Here, long-term flux tower observations of productivity and evapotranspiration allow us to detect a consistent latitudinal trend in WUE, rising from the subtropics to the northern high-latitudes. The trend peaks at approximately 51°N, and then declines toward higher latitudes. These ground-based observations are consistent with global-scale estimates of WUE. Global analysis of WUE reveals existence of strong regional variations that correspond to global climate patterns. The latitudinal trends of global WUE for Earth's major plant functional types reveal two peaks in the Northern Hemisphere not detected by ground-based measurements. One peak is located at 20° ~ 30°N and the other extends a little farther north than 51°N. Finally, long-term spatiotemporal trend analysis using satellite-based remote sensing data reveals that land-cover and land-use change in recent years has led to a decline in global WUE. Our study provides a new framework for global research on the interactions between carbon and water cycles as well as responses to natural and human impacts.

  17. Partition of some key regulating services in terrestrial ecosystems: Meta-analysis and review

    Energy Technology Data Exchange (ETDEWEB)

    Viglizzo, E.F., E-mail: evigliz@cpenet.com.ar [INTA, EEA Anguil, Grupo de Investigaciones en Gestión Ambiental (GIGA), Av. Spinetto 785, 6300 Santa Rosa, La Pampa (Argentina); INCITAP-CONICET, Ruta 35, km 335, 6300 Santa Rosa, La Pampa (Argentina); UNLPam, Facultad de Ciencias Exactas y Naturales, Av. Uruguay 151, 6300 Santa Rosa, La Pampa (Argentina); Jobbágy, E.G. [CONICET, Andes 950, 5700 San Luis, San Luis (Argentina); Grupo de Estudios Ambientales IMASL, Ejército de los, Andes 950, 5700 San Luis, San Luis (Argentina); Ricard, M.F. [INCITAP-CONICET, Ruta 35, km 335, 6300 Santa Rosa, La Pampa (Argentina); UNLPam, Facultad de Ciencias Exactas y Naturales, Av. Uruguay 151, 6300 Santa Rosa, La Pampa (Argentina); Paruelo, J.M. [Laboratorio de Análisis Regional y Teledetección, Departamento de Métodos Cuantitativos Sistemas de información, Facultad de Agronomía and IFEVA, Universidad de Buenos Aires and CONICET, Av. San Martín 4453, 1417 Buenos Aires (Argentina)

    2016-08-15

    Our knowledge about the functional foundations of ecosystem service (ES) provision is still limited and more research is needed to elucidate key functional mechanisms. Using a simplified eco-hydrological scheme, in this work we analyzed how land-use decisions modify the partition of some essential regulatory ES by altering basic relationships between biomass stocks and water flows. A comprehensive meta-analysis and review was conducted based on global, regional and local data from peer-reviewed publications. We analyzed five datasets comprising 1348 studies and 3948 records on precipitation (PPT), aboveground biomass (AGB), AGB change, evapotranspiration (ET), water yield (WY), WY change, runoff (R) and infiltration (I). The conceptual framework was focused on ES that are associated with the ecological functions (e.g., intermediate ES) of ET, WY, R and I. ES included soil protection, carbon sequestration, local climate regulation, water-flow regulation and water recharge. To address the problem of data normality, the analysis included both parametric and non-parametric regression analysis. Results demonstrate that PPT is a first-order biophysical factor that controls ES release at the broader scales. At decreasing scales, ES are partitioned as result of PPT interactions with other biophysical and anthropogenic factors. At intermediate scales, land-use change interacts with PPT modifying ES partition as it the case of afforestation in dry regions, where ET and climate regulation may be enhanced at the expense of R and water-flow regulation. At smaller scales, site-specific conditions such as topography interact with PPT and AGB displaying different ES partition formats. The probable implications of future land-use and climate change on some key ES production and partition are discussed. - Highlights: • The partition of regulatory services in ecosystems poses a major policy challenge. • We examined how partitions occur at the hydrosphere

  18. Partition of some key regulating services in terrestrial ecosystems: Meta-analysis and review

    International Nuclear Information System (INIS)

    Viglizzo, E.F.; Jobbágy, E.G.; Ricard, M.F.; Paruelo, J.M.

    2016-01-01

    Our knowledge about the functional foundations of ecosystem service (ES) provision is still limited and more research is needed to elucidate key functional mechanisms. Using a simplified eco-hydrological scheme, in this work we analyzed how land-use decisions modify the partition of some essential regulatory ES by altering basic relationships between biomass stocks and water flows. A comprehensive meta-analysis and review was conducted based on global, regional and local data from peer-reviewed publications. We analyzed five datasets comprising 1348 studies and 3948 records on precipitation (PPT), aboveground biomass (AGB), AGB change, evapotranspiration (ET), water yield (WY), WY change, runoff (R) and infiltration (I). The conceptual framework was focused on ES that are associated with the ecological functions (e.g., intermediate ES) of ET, WY, R and I. ES included soil protection, carbon sequestration, local climate regulation, water-flow regulation and water recharge. To address the problem of data normality, the analysis included both parametric and non-parametric regression analysis. Results demonstrate that PPT is a first-order biophysical factor that controls ES release at the broader scales. At decreasing scales, ES are partitioned as result of PPT interactions with other biophysical and anthropogenic factors. At intermediate scales, land-use change interacts with PPT modifying ES partition as it the case of afforestation in dry regions, where ET and climate regulation may be enhanced at the expense of R and water-flow regulation. At smaller scales, site-specific conditions such as topography interact with PPT and AGB displaying different ES partition formats. The probable implications of future land-use and climate change on some key ES production and partition are discussed. - Highlights: • The partition of regulatory services in ecosystems poses a major policy challenge. • We examined how partitions occur at the hydrosphere

  19. Impacts of inorganic fluorides on terrestrial ecosystems: An ecological risk assessment case study

    Energy Technology Data Exchange (ETDEWEB)

    Kent, R.A.; Schneider, U.A.; Pawlisz, A.V. [Environment Canada, Hull, Quebec (Canada). Evaluation and Interpretation Branch

    1995-12-31

    In 1994, the national environmental assessment under the Canadian Environmental Protection Act concluded that concentrations of inorganic fluorides near industrial sources in Canada may cause long-term adverse effects in sensitive terrestrial plant and wildlife species. This case study examines the accumulation of inorganic fluorides in vegetation and subsequent effects on a sensitive herbivore species, the white tail deer (Odocoileus virginianus) on Cornwall Island, Ontario, near an aluminum smelting facility, Using environmental concentration data for air, water and food (vegetation), a Monte Carlo simulation was used to estimate the probability that multimedia exposure of inorganic fluorides exceeded known effects thresholds of skeletal and dental fluorosis in deer, and in turn quantify the magnitude of that risk. With daily intakes ranging from 2--324 {micro}g/deer/day, it was estimated that exposure to fluorides exceeds the daily intake threshold for fluorosis (55 {micro}g/deer/day) in 12% of the deer population. Seasonal differences in exposure and subsequent risk were noted. These results are also supported by additional field data on domestic cattle from the Cornwall Island area where effects (e.g., excessive teeth wear, delayed eruption of permanent teeth, osteosclerosis, osteonecrosis) have been reported and linked to high levels of fluorides in air, water, and forage. It is estimated that at least 10% of the deer from the Cornwall Island area may be subject to debilitating skeletal and dental fluorosis as a result of fluoride emissions from the adjacent aluminum smelter.

  20. Modelling photochemical oxidant formation, transport, deposition and exposure of terrestrial ecosystems.

    Science.gov (United States)

    Fowler, D; Cape, J N; Coyle, M; Smith, R I; Hjellbrekke, A G; Simpson, D; Derwent, R G; Johnson, C E

    1999-01-01

    The chemical processes responsible for production of photochemical oxidants within the troposphere have been the subject of laboratory and field study throughout the last three decades. During the same period, models to simulate the atmospheric chemistry, transport and deposition of ozone (O(3)) from individual urban sources and from regions have been developed. The models differ greatly in the complexity of chemical schemes, in the underlying meteorology and in spatial and temporal resolution. Input information from land use, spatial and temporally disaggregated emission inventories and meteorology have all improved considerably in recent years and are not fully implemented in current models. The development of control strategies in both North America and Europe to close the gaps between current exceedances of environmental limits, guide values, critical levels or loads and full compliance with these limits provides the focus for policy makers and the support agencies for the research. The models represent the only method of testing a range of control options in advance of implementation. This paper describes currently applied models of photochemical oxidant production and transport at global and regional scales and their ability to simulate individual episodes as well as photochemical oxidant climatology. The success of current models in quantifying the exposure of terrestrial surfaces and the population to potentially damaging O(3) concentrations (and dose) is examined. The analysis shows the degree to which the underlying processes and their application within the models limit the quality of the model products.

  1. Bounding uncertainty in volumetric geometric models for terrestrial lidar observations of ecosystems

    Science.gov (United States)

    Genest, Daniel; Peri, Francesco; Schaaf, Crystal

    2018-01-01

    Volumetric models with known biases are shown to provide bounds for the uncertainty in estimations of volume for ecologically interesting objects, observed with a terrestrial laser scanner (TLS) instrument. Bounding cuboids, three-dimensional convex hull polygons, voxels, the Outer Hull Model and Square Based Columns (SBCs) are considered for their ability to estimate the volume of temperate and tropical trees, as well as geomorphological features such as bluffs and saltmarsh creeks. For temperate trees, supplementary geometric models are evaluated for their ability to bound the uncertainty in cylinder-based reconstructions, finding that coarser volumetric methods do not currently constrain volume meaningfully, but may be helpful with further refinement, or in hybridized models. Three-dimensional convex hull polygons consistently overestimate object volume, and SBCs consistently underestimate volume. Voxel estimations vary in their bias, due to the point density of the TLS data, and occlusion, particularly in trees. The response of the models to parametrization is analysed, observing unexpected trends in the SBC estimates for the drumlin dataset. Establishing that this result is due to the resolution of the TLS observations being insufficient to support the resolution of the geometric model, it is suggested that geometric models with predictable outcomes can also highlight data quality issues when they produce illogical results. PMID:29503722

  2. Dynamic of biogeochemical selenium cycle in terrestrial ecosystems: retention and reactivity in soil; role of vegetation

    International Nuclear Information System (INIS)

    Di Tullo, Pamela

    2015-01-01

    This work was performed in the frame of the safety assessment program prior to the possible construction of an underground repository for nuclear waste (HAVL). To consolidate risk assessment models associated to a potential 79 Se biosphere contamination, biogeochemistry of stable selenium was investigated, aiming firstly to highlight the dynamics of Se cycling in a forest ecosystem, in terms of inventories and annual fluxes. Consequently to these first results, which suggest a clay role of soil and its organic pool in the global Se cycle, two studies based on the use of isotopically enriched tracers were further carried out in order to clarify the processes involved in (i) Se retention and reactivity in soils and (ii) incorporation of inorganic Se within organic pool of vegetal biomass. (author) [fr

  3. Understanding Late Triassic low latitude terrestrial ecosystems: new insights from the Colorado Plateau Coring Project (CPCP)

    Science.gov (United States)

    Irmis, R. B.; Olsen, P. E.; Parker, W.; Rasmussen, C.; Mundil, R.; Whiteside, J. H.

    2017-12-01

    The Chinle Formation of southwestern North America is a key paleontological archive of low paleolatitude non-marine ecosystems that existed during the Late Triassic hothouse world. These strata were deposited at 5-15°N latitude, and preserve extensive plant, invertebrate, and vertebrate fossil assemblages, including early dinosaurs; these organisms lived in an unpredictably fluctuating semi-arid to arid environment with very high atmospheric pCO2. Despite this well-studied fossil record, a full understanding of these ecosystems and their integration with other fossil assemblages globally has been hindered by a poor understanding of the Chinle Formation's age, duration, and sedimentation rates. Recently, the CPCP recovered a 520m continuous core through this formation from the northern portion of Petrified Forest National Park (PEFO) in northern Arizona, USA. This core has provided a plethora of new radioisotopic and magnetostratigraphic data from fresh, unweathered samples in unambiguous stratigraphic superposition. These constraints confirm that virtually all fossil-bearing horizons in Chinle outcrops in the vicinity of PEFO are Norian in age. Furthermore, they indicate that the palynomorph zone II and Adamanian vertebrate biozone are at least six million years long, whereas the overlying palynomorph zone III and Revueltian vertebrate biozone persisted for at least five million years, with the boundary between 216-214 Ma. This confirms that the rich late Adamanian-early Revueltian vertebrate fossil assemblages, where dinosaurs are exclusively rare, small-bodied carnivorous theropods, are contemporaneous with higher latitude assemblages in Europe, South America, and Africa where large-bodied herbivorous sauropodomorph dinosaurs are common. The age constraints also confirm that several palynomorph biostratigraphic ranges in the Chinle Formation differ from those of the same taxa in eastern North American (Newark Supergroup) and Europe. These data are consistent

  4. Metagenomic insights into S(0 precipitation in a terrestrial subsurface lithoautotrophic ecosystem

    Directory of Open Access Journals (Sweden)

    Trinity eHamilton

    2015-01-01

    Full Text Available The Frasassi and Acquasanta Terme cave systems in Italy host isolated lithoautotrophic ecosystems characterized by sulfur-oxidizing biofilms with up to 50% S(0 by mass. The net contributions of microbial taxa in the biofilms to production and consumption of S(0 are poorly understood and have implications for understanding the formation of geological sulfur deposits as well as the ecological niches of sulfur-oxidizing autotrophs. Filamentous Epsilonproteobacteria are among the principal biofilm architects in Frasassi and Acquasanta Terme streams, colonizing high-sulfide, low-oxygen niches relative to other major biofilm-forming populations. Metagenomic sequencing of eight biofilm samples indicated the presence of diverse and abundant Epsilonproteobacteria. Populations of Sulfurovum-like organisms were the most abundant Epsilonproteobacteria regardless of differences in biofilm morphology, temperature, or water chemistry. After assembling and binning the metagenomic data, we retrieved four nearly-complete genomes of Sulfurovum-like organisms as well as a Sulfuricurvum spp. Analyses of the binned and assembled metagenomic data indicate that the Epsilonproteobacteria are autotrophic and therefore provide organic carbon to the isolated subsurface ecosystem. Multiple homologs of sulfide-quinone oxidoreductase (Sqr, together with incomplete or absent Sox pathways, suggest that cave Sulfurovum-like Epsilonproteobacteria oxidize sulfide incompletely to S(0 using either O2 or nitrate as a terminal electron acceptor, consistent with previous evidence that they are most successful in niches with high dissolved sulfide to oxygen ratios. In contrast, we recovered homologs of the complete complement of Sox proteins affiliated Gammaproteobacteria and with less abundant Sulfuricurvum spp. and Arcobacter spp., suggesting that these populations are capable of the complete oxidation of sulfide to sulfate. These and other genomic data presented here offer new clues

  5. Responses of terrestrial herpetofauna to persistent, novel ecosystems resulting from mountaintop removal mining

    Science.gov (United States)

    Williams, Jennifer M.; Brown, Donald J.; Wood, Petra

    2017-01-01

    Mountaintop removal mining is a large-scale surface mining technique that removes entire floral and faunal communities, along with soil horizons located above coal seams. In West Virginia, the majority of this mining occurs on forested mountaintops. However, after mining ceases the land is typically reclaimed to grasslands and shrublands, resulting in novel ecosystems. In this study, we examined responses of herpetofauna to these novel ecosystems 10–28 y postreclamation. We quantified differences in species-specific habitat associations, (sub)order-level abundances, and habitat characteristics in four habitat types: reclaimed grassland, reclaimed shrubland, forest fragments in mined areas, and nonmined intact forest. Habitat type accounted for 33.2% of the variation in species-specific captures. With few exceptions, forest specialists were associated with intact forest and fragmented forest sites, while habitat generalists were either associated with grassland and shrubland sites or were distributed among all habitat types. At the (sub)order level, salamander (Order Urodela) captures were highest at fragmented and intact forest sites, frog and toad (Order Anura) captures were lowest at intact forest sites, and snake (Suborder Serpentes) captures were highest at shrubland sites. Habitat type was a strong predictor for estimated total abundance of urodeles, but not for anurans or snakes. Tree stem densities in grasslands differed from the other three habitat types, and large trees (>38 cm diameter at breast height) were only present at forest sites. Overstory vegetation cover was greater in forested than in reclaimed habitat types. Ground cover in reclaimed grasslands was distinct from forest treatments with generally less woody debris and litter cover and more vegetative cover. It is important to consider the distributions of habitat specialists of conservation concern when delineating potential mountaintop mine sites, as these sites will likely contain unsuitable

  6. Impacts of acid emissions from Nevado del Ruiz volcano, Colombia, on selected terrestrial and aquatic ecosystems

    Science.gov (United States)

    Parnell, Roderic A.; Burke, Kelly J.

    1990-07-01

    Emissions of acidic gases and thermal waters from Nevado del Ruiz volcano have recently increased in concert with the November 13, 1985 eruption. This study examines the downwind and downstream effects of these emissions on alpine ecosystems high on the slopes of the volcano (4100 m) and on coffee plantations at lower elevations ( 30 km). Samples of bulk deposition, rain, soils, soil solutions, and streams were collected over a six-month period (January-July, 1987) to examine the impacts of this volcanogenic acidity. Bulk deposition falling on the higher slopes of the volcano is usually acidified; however, deposition reaching the distal coffee plantations seldom is acidic. The sources of the acids are hydrogen chloride and sulfur dioxide in the plume of the volcano. Although sulfur dioxide is by far the more abundant gas, hydrogen chloride is most responsible for acidification of rain falling on the slopes of the volcano. With distance from the vent, the chloride/sulfate ratio drops exponentially. The only major influence on regional precipitation chemistry in addition to the volcano appears to be land-use-related activities around the coffee plantations. Deposition on these areas is enriched by an order of magnitude in nitrate and base cations, compared to all other stations. Throughfall chemistry in the coffee plantations shows a dramatic response to occasional acid-rain events. A base-leaching process on coffee plant leaves is triggered by acid rain. For each equivalent of hydrogen ion in rain on the leaf surface, over 23 equivalents of potassium ion are leached from the leaf. In spite of this dramatic response by the vegetation, the plantation soils appear relatively unaffected by acidic deposition. In contrast, the alpine soils on the volcano exhibit low pHs, high sulfate and chloride concentrations in soil solutions, and high extractable sulfate concentrations. All of these factors indicate that these soils have undergone significant acid loading. While the

  7. Modelling of plant-soil carbon, nitrogen and phosphorus cycling in semi-natural terrestrial ecosystems

    Science.gov (United States)

    Davies, Jessica; Quinton, John; Rowe, Ed; Tipping, Ed

    2013-04-01

    In recent centuries pools and fluxes of C, N and P in natural and semi-natural UK ecosystems have been transformed by atmospheric pollution leading to: acidification; eutrophication of surface waters; loss of biodiversity; and increased greenhouse gas emissions. In addition, climate change now threatens to perturb these systems further. Understanding in this field is vital in determining the consequences of artificial nutrient enrichment and land use and climate change, and mitigating against their effects. The N14CP model has been recently developed to assess the temporal responses of soil C, N and P pools to nutrient enrichment in semi-natural ecosystems, and explore the connections between these nutrients. It is a dynamic, mechanistic model, driven by: climate; CO2, N (fixation and pollutant deposition), and P (weathering and atmospheric deposition) inputs; and plant cover type. It explicitly links C, N, and P in both plants and soils, using plant element stoichiometry as the primary constraint. Net primary production, and plant/soil element pools, are calculated over time, and output fluxes of dissolved organic and inorganic, and gaseous, forms of C, N, and P produced. Radiocarbon data are used to constrain Soil Organic Matter (SOM) turnover. The SOM is represented as three pools, undergoing first-order decomposition reactions with turn-over rates ranging from 2 to 1000 years. The N14CP modelling methodology is discussed and its calibration and verification using observations from 200 northern European sites presented. Whilst the primary period of interest with respect to nutrient enrichment is from the industrial revolution onwards, plant-soil C, N and P are simulated at these sites for a period spanning from the start of the Holocene (to provide a spin-up period) to the present day. Clearly, during this time span land cover and usage will have changed at these sites, and histories of these changes are used as an input to the model. The influence of these land

  8. Comparing the influence of wildfire and prescribed burns on watershed nitrogen biogeochemistry using 15N natural abundance in terrestrial and aquatic ecosystem components.

    Science.gov (United States)

    Stephan, Kirsten; Kavanagh, Kathleen L; Koyama, Akihiro

    2015-01-01

    We evaluated differences in the effects of three low-severity spring prescribed burns and four wildfires on nitrogen (N) biogeochemistry in Rocky Mountain headwater watersheds. We compared paired (burned/unburned) watersheds of four wildfires and three spring prescribed burns for three growing seasons post-fire. To better understand fire effects on the entire watershed ecosystem, we measured N concentrations and δ15N in both the terrestrial and aquatic ecosystems components, i.e., soil, understory plants in upland and riparian areas, streamwater, and in-stream moss. In addition, we measured nitrate reductase activity in foliage of Spiraea betulifolia, a dominant understory species. We found increases of δ15N and N concentrations in both terrestrial and aquatic ecosystem N pools after wildfire, but responses were limited to terrestrial N pools after prescribed burns indicating that N transfer from terrestrial to aquatic ecosystem components did not occur in low-severity prescribed burns. Foliar δ15N differed between wildfire and prescribed burn sites; the δ15N of foliage of upland plants was enriched by 2.9 ‰ (difference between burned and unburned watersheds) in the first two years after wildfire, but only 1.3 ‰ after prescribed burns. In-stream moss δ15N in wildfire-burned watersheds was enriched by 1.3 ‰, but there was no response by moss in prescription-burned watersheds, mirroring patterns of streamwater nitrate concentrations. S. betulifolia showed significantly higher nitrate reductase activity two years after wildfires relative to corresponding unburned watersheds, but no such difference was found after prescribed burns. These responses are consistent with less altered N biogeochemistry after prescribed burns relative to wildfire. We concluded that δ15N values in terrestrial and aquatic plants and streamwater nitrate concentrations after fire can be useful indicators of the magnitude and duration of fire effects and the fate of post

  9. Nitrogen Availability Dampens the Positive Impacts of CO2 Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

    Science.gov (United States)

    He, Liming; Chen, Jing M.; Croft, Holly; Gonsamo, Alemu; Luo, Xiangzhong; Liu, Jane; Zheng, Ting; Liu, Ronggao; Liu, Yang

    2017-11-01

    The magnitude and variability of the terrestrial CO2 sink remain uncertain, partly due to limited global information on ecosystem nitrogen (N) and its cycle. Without N constraint in ecosystem models, the simulated benefits from CO2 fertilization and CO2-induced increases in water use efficiency (WUE) may be overestimated. In this study, satellite observations of a relative measure of chlorophyll content are used as a proxy for leaf photosynthetic N content globally for 2003-2011. Global gross primary productivity (GPP) and evapotranspiration are estimated under elevated CO2 and N-constrained model scenarios. Results suggest that the rate of global GPP increase is overestimated by 85% during 2000-2015 without N limitation. This limitation is found to occur in many tropical and boreal forests, where a negative leaf N trend indicates a reduction in photosynthetic capacity, thereby suppressing the positive vegetation response to enhanced CO2 fertilization. Based on our carbon-water coupled simulations, enhanced CO2 concentration decreased stomatal conductance and hence increased WUE by 10% globally over the 1982 to 2015 time frame. Due to increased anthropogenic N application, GPP in croplands continues to grow and offset the weak negative trend in forests due to N limitation. Our results also show that the improved WUE is unlikely to ease regional droughts in croplands because of increases in evapotranspiration, which are associated with the enhanced GPP. Although the N limitation on GPP increase is large, its associated confidence interval is still wide, suggesting an urgent need for better understanding and quantification of N limitation from satellite observations.

  10. Can Surface Seeps Elucidate Carbon Cycling in Terrestrial Subsurface Ecosystems in Ophiolite-hosted Serpentinizing Fluids?

    Science.gov (United States)

    Meyer-Dombard, D. R.; Cardace, D.; Woycheese, K. M.; Vallalar, B.; Arcilla, C. A.

    2017-12-01

    Serpentinization in ophiolite-hosted regimes produces highly reduced, high pH fluids that are often characterized as having copious H2 and CH4 gas, little/no inorganic carbon, and limited electron acceptors. Subsurface microbial biomes shift as deeply-sourced fluids reach the oxygenated surface environment, where organisms capable of metabolizing O2 thrive (Woycheese et al., 2015). The relationship, connection, and communication between surface expressions (such as fluid seeps) and the subsurface biosphere is still largely unexplored. Our work in the Zambales and Palawan ophiolites (Philippines) defines surface habitats with geochemistry, targeted culturing efforts, and community analysis (Cardace et al., 2015; Woycheese et al., 2015). Fluids in the spring sources are largely `typical' and fall in the pH range of 9-11.5 with measurable gas escaping from the subsurface (H2 and CH4 > 10uM, CO2 > 1 mM; Cardace et al., 2015). Outflow channels extend from the source pools. These surface data encourage prediction of the subsurface metabolic landscape. To understand how carbon cycling in the subsurface and surface environments might be related, we focus on community analysis, culturing, and the geochemical context of the ecosystem. Shotgun metagenomic analyses indicate carbon cycling is reliant on methanogenesis, acetogenesis, sulfate reduction, and H2 and CH4 oxidation. Methyl coenzyme M reductase, and formylmethanofuran dehydrogenase were detected, and relative abundance increased near the near-anoxic spring source. In this tropical climate, cellulose is also a likely carbon source, possibly even in the subsurface. Enrichment cultures [pH 8-12] and strains [pH 8-10] from Zambales springs show degradation of cellulose and production of cellulase. DIC, DOC, and 13C of solid substrates show mixed autotrophic/heterotrophic activity. Results indicate a metabolically flexible surface community, and suggest details about carbon cycling in the subsurface.

  11. Ecotoxicity of selected antibiotics for organisms of aquatic and terrestrial ecosystems.

    Science.gov (United States)

    Havelkova, Barbora; Beklova, Miroslava; Kovacova, Veronika; Hlavkova, Daniela; Pikula, Jiri

    2016-12-18

    The aim of this study was to assess the ecotoxicity of selected antibiotics (i.e. penicillin G, vancomycin and tetracycline) using ecotoxicological tests. Tests were conducted on organisms representing all trophic levels of the aquatic ecosystem, namely producers (green freshwater algae Pseudokirchneriella subcapitata), consumers (water fleas Daphnia magna) and decomposers (bacteria Vibrio fischeri). The effect of antibiotics on the representative of edaphon was measured by testing the inhibition of the reproduction of springtails Folsomia candida and earthworms Eisenia fetida. Methodologically, the procedure was carried out in accordance with the following standards: OECD 201 (Fresh water algal growth inhibition test), OECD 202 (Inhibition of the mobility of Daphnia magna), ISO 11348-2 (Inhibitory effect of antibiotics on the light emission of Vibrio fischeri), OECD 232 (Inhibition of reproduction of Collembola Folsomia candida) and OECD 222 (Inhibition of reproduction of Eisenia fetida). In aquatic organisms the highest level of toxicity was shown by tetracycline to algae (72hEC50 = 1.82 mg.l-1) and daphnia (48hEC50 = 8.16 mg.l-1). The least toxic for all test organisms was penicillin G. The results of the tests performed on the representative of edaphon, Folsomia candida, showed that its reproduction was most inhibited by penicillin G (28dEC50 = 328 mg.kg-1) and least by tetracycline (28dEC50 = 2560 mg.kg-1). Similar results were observed in Eisenia fetida (56dEC50 = 348 mg.kg-1 for penicillin G and 56dEC50 = 2735 mg.kg-1 for tetracycline. The ecotoxicity of antibiotics differed significantly depending on the test organism and testing conditions.

  12. Water use by terrestrial ecosystems: temporal variability in rainforest and agricultural contributions to evapotranspiration in Mato Grosso, Brazil

    International Nuclear Information System (INIS)

    Lathuillière, Michael J; Johnson, Mark S; Donner, Simon D

    2012-01-01

    The state of Mato Grosso, Brazil, has experienced rapid land use changes from the expansion of rain-fed agriculture (primarily soybean and pasture). This study presents changes to evapotranspiration contributions from terrestrial ecosystems in Mato Grosso over the 2000–9 period. Instead of focusing on land use change to infer hydrologic change, in this paper we assess hydrologic changes using remote sensing, meteorological and agricultural production data to determine the rainforest, crop and pasture components of total evapotranspiration. Humid tropical rainforest evapotranspiration represented half of the state’s total evapotranspiration in 2000 despite occupying only 40% of the total land area. Annual evapotranspiration fluxes from rainforest declined at a rate of 16.2 km 3 y −1 (R 2 = 0.82, p-value < 0.01) as a result of deforestation between 2000 and 2009, representing a 25% decline in rainforest evapotranspiration since 2000. By 2009, rainforest cover accounted for only 40% of total evapotranspiration. Over the same period, crop evapotranspiration doubled, but this increase was offset by a decline in pasture evapotranspiration. Pasture fluxes were at least five times larger than crop evapotranspiration fluxes in 2000–9, with increases spatially focused at the agricultural frontier. The results highlight the expanding appropriation of soil moisture stocks for use in Mato Grosso’s rain-fed agroecosystems. (letter)

  13. Net exchanges of CO2, CH4 and N2O between the terrestrial ecosystems and the atmosphere in boreal and arctic region: Towards a full greenhouse gas budget

    Science.gov (United States)

    Zhang, B.; Tian, H.; Lu, C.; Yang, J.; Kamaljit, K.; Pan, S.

    2014-12-01

    Boreal and arctic terrestrial ecosystem is a unique ecological region due to large portion of wetland and permafrost distribution. Increasing disturbances, like permafrost-thaw, fire event, climate extreme, would greatly change the patterns and variations of greenhouse gas emission and further affect the feedback between terrestrial ecosystem and climate change. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) accounted for more than 85% of the radioactive forcing (RF) due to long-lived greenhouse gases. However, few studies have considered the full budget of three gases together in this region. In this study, we used a process-based model (Dynamic Land Ecosystem Model), driven by multiple global change factors, to quantify the magnitude, spatial and temporal variation of CO2, CH4 and N2O across the boreal and arctic regions. Simulated results have been evaluated against field observations, inventory-based and atmospheric inversion estimates. By implementing a set of factorial simulations, we further quantify the relative contribution of climate, atmospheric composition, fire to the CO2, CH4 and N2O fluxes. Continued warming climate potentially could shift the inter-annual and intra-annual variation of greenhouse gases fluxes. The understanding of full budget in this region could provide insights for reasonable future projection, which is also crucial for developing effective mitigation strategies.

  14. Shifts of community composition and population density substantially affect ecosystem function despite invariant richness.

    Science.gov (United States)

    Spaak, Jurg W; Baert, Jan M; Baird, Donald J; Eisenhauer, Nico; Maltby, Lorraine; Pomati, Francesco; Radchuk, Viktoriia; Rohr, Jason R; Van den Brink, Paul J; De Laender, Frederik

    2017-10-01

    There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community composition. Using a theoretical model, we find that, despite invariant richness, (1) small environmental effects may already lead to a collapse of function; (2) competitive strength may be a less important determinant of ecosystem function change than the selectivity of the environmental change driver and (3) effects on ecosystem function increase when effects on composition are larger. We also present a complementary statistical analysis of 13 data sets of phytoplankton and periphyton communities exposed to chemical stressors and show that effects on primary production under invariant richness ranged from -75% to +10%. We conclude that environmental protection goals relying on measures of richness could underestimate ecological impacts of environmental change. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  15. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    International Nuclear Information System (INIS)

    Marek, Michal V.; Janous, Dalibor; Taufarova, Klara; Havrankova, Katerina; Pavelka, Marian; Kaplan, Veroslav; Markova, Irena

    2011-01-01

    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. - Highlights: → Highest carbon sequestration potential in evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). → The final carbon gain of the grassland was negative (massive ecosystem respiration). → Climate is important factor of net primary productivity. → Carbon uptake is strongly affected by the ontogeny and a production strategy of ecosystem. - Identification of the apparent differences in the carbon storage by different ecosystem types.

  16. Uncertainties in carbon residence time and NPP-driven carbon uptake in terrestrial ecosystems of the conterminous USA: a Bayesian approach

    Directory of Open Access Journals (Sweden)

    Xuhui Zhou

    2012-10-01

    Full Text Available Carbon (C residence time is one of the key factors that determine the capacity of ecosystem C storage. However, its uncertainties have not been well quantified, especially at regional scales. Assessing uncertainties of C residence time is thus crucial for an improved understanding of terrestrial C sequestration. In this study, the Bayesian inversion and Markov Chain Monte Carlo (MCMC technique were applied to a regional terrestrial ecosystem (TECO-R model to quantify C residence times and net primary productivity (NPP-driven ecosystem C uptake and assess their uncertainties in the conterminous USA. The uncertainty was represented by coefficient of variation (CV. The 13 spatially distributed data sets of C pools and fluxes have been used to constrain TECO-R model for each biome (totally eight biomes. Our results showed that estimated ecosystem C residence times ranged from 16.6±1.8 (cropland to 85.9±15.3 yr (evergreen needleleaf forest with an average of 56.8±8.8 yr in the conterminous USA. The ecosystem C residence times and their CV were spatially heterogeneous and varied with vegetation types and climate conditions. Large uncertainties appeared in the southern and eastern USA. Driven by NPP changes from 1982 to 1998, terrestrial ecosystems in the conterminous USA would absorb 0.20±0.06 Pg C yr−1. Their spatial pattern was closely related to the greenness map in the summer with larger uptake in central and southeast regions. The lack of data or timescale mismatching between the available data and the estimated parameters lead to uncertainties in the estimated C residence times, which together with initial NPP resulted in the uncertainties in the estimated NPP-driven C uptake. The Bayesian approach with MCMC inversion provides an effective tool to estimate spatially distributed C residence time and assess their uncertainties in the conterminous USA.

  17. Variations and trends of terrestrial NPP and its relation to climate ...

    Indian Academy of Sciences (India)

    Considering global climate change, near surface temperature is the major factor affecting the terrestrial ecosystem, followed by the precipitation. This means terrestrial ecosystem NPP is more closely related to near surface temperature than precipitation. Between 1976 and 2005, NPP shows an obvious increasing temporal ...

  18. Variations and trends of terrestrial NPP and its relation to climate

    Indian Academy of Sciences (India)

    Considering global climate change, near surface temperature is the major factor affecting the terrestrial ecosystem, followed by the precipitation. This means terrestrial ecosystem NPP is more closely related to near surface temperature than precipitation. Between 1976 and 2005, NPP shows an obvious increasing temporal ...

  19. Terrestrial pyrogenic carbon export to fluvial ecosystems: Lessons learned from the White Nile watershed of East Africa

    Science.gov (United States)

    Güereña, David T.; Lehmann, Johannes; Walter, Todd; Enders, Akio; Neufeldt, Henry; Odiwour, Holiance; Biwott, Henry; Recha, John; Shepherd, Keith; Barrios, Edmundo; Wurster, Chris

    2015-11-01

    Pyrogenic carbon (PyC) is important because of its role in the global organic C (OC) cycle and in modifying soil properties. However, our understanding of PyC movement from terrestrial to fluvial ecosystems is not robust. This study examined (i) whether erosion or subsurface transport was more important for PyC export from headwaters, (ii) whether PyC was exported preferentially to total OC (TOC), and (iii) whether the movement of PyC from terrestrial to aquatic ecosystems provides an explanation for the coupling of PyC and non-PyC observed in rivers at a global scale. In the Guineo-Congolian highland forest region of western Kenya, duplicate catchments with sizes of 1-12 ha were equipped with stream gauges in primary forest and adjacent mixed agricultural landscapes that were cleared by fire 10, 16, or 62 years before. Stream water samples were taken weekly throughout 1 year and compared with runoff to assess PyC movement. Additional stream samples were taken from all major tributaries of the White Nile watershed of Lake Victoria. PyC was not found to be preferentially eroded relative to TOC or non-PyC, as topsoil (0-0.15 m) PyC concentrations (6.3 ± 0.3% of TOC; means and standard errors) were greater than runoff sediment (1.9 ± 0.4%) and dissolved PyC concentrations (2.0 ± 0.4%, n = 252). In addition, PyC proportions in eroded sediment were lower than and uncorrelated (r2 = 0.04; P = 0.14) with topsoil PyC. An enrichment of PyC was found with depth in the soil, from 6.3 ± 0.3% of TOC in the topsoil (0-0.15 m) to 12.3 ± 0.3% of TOC at 1-2 m. Base flow PyC proportions of TOC correlated well with subsoil PyC (r2 = 0.57; P 0.05). Similar PyC proportions were found in the studied headwater streams (2.7 ± 0.2%), their downstream inflow into Lake Victoria (3.7%), the other nine major rivers into Lake Victoria (4.9 ± 0.8%), and its outflow into the White Nile (1.1%). A strong positive correlation between dissolved PyC and non-PyC (r2 = 0.91; P the headwater

  20. Recording of ecological half-lives of 90Sr and 137Cs in terrestrial and aquatic ecosystems

    International Nuclear Information System (INIS)

    Proehl, G.; Fiedler, I.; Ehlken, S.

    2004-01-01

    Within this project, the long-term behaviour of 90 Sr and 137 Cs in foods, feeds and a variety of environmental was analysed. The long-term behaviour is quantified by means of the ecological half-life which integrates all processes that cause a decrease of activity in a given medium as leaching, fixation and erosion. The following results were achieved: - For plant and animal food products, the ecological half-lives are in the range of 4 to 6 and 10 to 20 years for cesium and strontium respectively. The ecological half-lives for the period 1965 to 1985 are slightly shorter than those derived from monitoring measurements performed after 1987, due to the ongoing deposition in the post weapons' fallout period. - According to the German radioecological model that is applied during licensing of nuclear installations to assess radiation exposures to the general due to planned releases, the ecological half-lives for plant food products are 26 and 13 a for cesium and strontium respectively. In radioecological model that is used within the decision support system RODOS, the ecological half-lives are 8 years for Cesium and 14 years for strontium, which agrees well with the finding of this study. - For roe deer, deer, wild boar and forest plants (including mushrooms), under Middle European conditions, the ecological half-lives are about 12 years for cesium. However, in Ukraine, the cesium levels in forest products are much more persistent; in some cases the decrease of activity is only caused by the radioactive decay. - The variability of the long-term behaviour of 137Cs and 90Sr in freshwater ecosystems is much more pronounced than for terrestrial systems. It depends strongly on the sitespecific characteristics. The observed ecological half-lives for 137Cs and 90Sr cover a wide range from several days to several years. - The data to derive ecological half-lives of cesium in soil is relatively poor. For the upper soil layer of 0-10 cm, ecological half-lives were derived

  1. Terrestrial ecosystem model performance in simulating productivity and its vulnerability to climate change in the northern permafrost region

    Science.gov (United States)

    Xia, Jianyang; McGuire, A. David; Lawrence, David; Burke, Eleanor J.; Chen, Guangsheng; Chen, Xiaodong; Delire, Christine; Koven, Charles; MacDougall, Andrew; Peng, Shushi; Rinke, Annette; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Decharme, Bertrand; Gouttevin, Isabelle; Hajima, Tomohiro; Hayes, Daniel J.; Huang, Kun; Ji, Duoying; Krinner, Gerhard; Lettenmaier, Dennis P.; Miller, Paul A.; Moore, John C.; Smith, Benjamin; Sueyoshi, Tetsuo; Shi, Zheng; Yan, Liming; Liang, Junyi; Jiang, Lifen; Zhang, Qian; Luo, Yiqi

    2017-01-01

    Realistic projection of future climate-carbon (C) cycle feedbacks requires better understanding and an improved representation of the C cycle in permafrost regions in the current generation of Earth system models. Here we evaluated 10 terrestrial ecosystem models for their estimates of net primary productivity (NPP) and responses to historical climate change in permafrost regions in the Northern Hemisphere. In comparison with the satellite estimate from the Moderate Resolution Imaging Spectroradiometer (MODIS; 246 ± 6 g C m−2 yr−1), most models produced higher NPP (309 ± 12 g C m−2 yr−1) over the permafrost region during 2000–2009. By comparing the simulated gross primary productivity (GPP) with a flux tower-based database, we found that although mean GPP among the models was only overestimated by 10% over 1982–2009, there was a twofold discrepancy among models (380 to 800 g C m−2 yr−1), which mainly resulted from differences in simulated maximum monthly GPP (GPPmax). Most models overestimated C use efficiency (CUE) as compared to observations at both regional and site levels. Further analysis shows that model variability of GPP and CUE are nonlinearly correlated to variability in specific leaf area and the maximum rate of carboxylation by the enzyme Rubisco at 25°C (Vcmax_25), respectively. The models also varied in their sensitivities of NPP, GPP, and CUE to historical changes in climate and atmospheric CO2 concentration. These results indicate that model predictive ability of the C cycle in permafrost regions can be improved by better representation of the processes controlling CUE and GPPmax as well as their sensitivity to climate change.

  2. Monitoring the effects of air pollution on terrestrial ecosystems in Varanger (Norway) and Nikel Pechenga (Russian Federation) using remote sensing

    International Nuclear Information System (INIS)

    Tommervik, H.; Johansen, B.E.; Pedersen, J.P.

    1995-01-01

    During the period 1988-1993, NORUT Information Technology carried out a research project on the effects of air pollution on terrestrial ecosystems in the areas of Varanger (Norway) and Nikel-Pechenga (Russia). To maintain environmental surveillance over the extensive border area, NORUT used satellite remote sensing data in combination with ground measurements. During the project, we produced vegetation cover maps for four different years (1973, 1979, 1985 and 1988), a change detection image, and a vegetation change map. One of the major changes that can be observed on the vegetation cover maps is that the area with licehn-dominated vegetation decreased from 2783 km 2 in 1973 to 538 km 2 in 1988. Comparison of the vegetation cover maps and the change detection map with the total number of emissions of SO 2 from industry shows a strong correlation between the decrease in lichen-dominated vegetation and the dramatic increase in emissions in the period 1973-1988. A correlation between the degradation of the vegetation and the SO 2 concentration in the air has also been documented. The area of severe air pollution impacts increased from approximately 400 km 2 in 1973 to more than 5000 km 2 in 1988. This study shows that the critical loads/levels of air pollution have been exceeded for lichen-dominated vegetation cover types in the eastern parts of the study area. Finally, this study concludes that the use of optical remote sensing (Landsat MSS data) to map vegetation cover changes related to the impacts of air pollution was successful, with an overall classification accuracy of about 80%

  3. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Allen, S.E.; Horrill, A.D.; Howard, B.J.; Lowe, V.P.W.; Parkinson, J.A.

    1983-07-01

    The subject is discussed under the headings: concentration and spatial distribution of radionuclides in grazed and ungrazed saltmarshes; incorporation of radionuclides by sheep grazing on an estuarine saltmarsh; inland transfer of radionuclides by birds feeding in the estuaries and saltmarshes at Ravenglass; radionuclides in contrasting types of coastal pastures and taken up by individual plant species found in west Cumbria; procedures developed and used for the measurement of alpha and gamma emitters in environmental materials. (U.K.)

  4. Terrestrial ecosystems and biodiversity

    CSIR Research Space (South Africa)

    Davis-Reddy, Claire

    2017-10-01

    Full Text Available concentrations of endemic plant and animal species, but these mainly occur in areas that are most threatened by human activity. Changes in climate, combined with land-use change and the spread of invasive species, are likely to limit the resilience...

  5. Component modeling in ecological risk assessment: Disturbance in interspecific interactions caused by air toxics introduced into terrestrial ecosystems

    Science.gov (United States)

    Swider, Jan Zenon

    The human health risk assessment (HRA), initiated by the onset of nuclear industry, has been a well established methodology for assessing the impacts of human created contamination on an individual human being and entire population. The wide spread of applications and tools grown upon this methodology allows one not only to identify the hazards, but also to manage the risks. Recently, there has existed an increased awareness of the need to conduct ecological risk assessments (ERA) in addition to HRAs. The ERAs are, by and large, more complex than typical HRAs and involve not only different species but whole ecological systems. Such complex analyses require a thorough understanding of the processes underway in the ecosystem, including the contaminant transport through the food web, population dynamics as well as intra- and inter-specific relationships. The exposure pathways change radically depending on the consumer tier. Plants produce their nutriment from the sunlight and raw inorganic compounds. Animals and other living forms obtain energy by eating plants, other animals and detritus. Their double role as food consumers and food producers causes a trophic structure of the ecological system, where nutrients and energy are transferred from one trophic level to another. This is a dynamic process of energy flow, mostly in the form of food, varying with time and space. In order to conduct an efficient ERA, a multidisciplinary framework is needed. This framework can be enhanced by analyzing predator-prey interactions during the environmental disturbances caused by a pollutant emission, and by assessing the consequences of such disturbances. It is necessary to develop a way to describe how human industrial activity affects the ecosystems. Existing ecological studies have mostly been focused either on pure ecological interdependencies or on limited perspectives of human activities. In this study, we discuss the issues of air pollution and its ecological impacts from the

  6. How disturbances and management practices affect bird communities in a Carpathian river ecosystem?

    Science.gov (United States)

    Lacko, Jozef; Topercer, Ján; Súľovský, Marek

    2018-04-01

    We studied how interactions between disturbances, succession, human alterations and other habitat and landscape attributes affect bird community patterns in a lower reach of a large West Carpathian river Váh with complex disturbance and alteration histories. Breeding-bird communities, their habitats (54 variables) and surrounding landscapes (11 metrics) were sampled using standardized point counts with limited distances at 40 riparian sites divided among two transects along a 12.9 km river stretch. The most frequent and abundant birds were generalists typically associated with forest edge habitats, such as Parus major, Sylvia atricapilla, Fringilla coelebs, Oriolus oriolus, Phylloscopus collybita, Sturnus vulgaris, Turdus merula and Luscinia megarhynchos. Abundances show significant increase at the lower transect responding apparently to greater size and heterogeneity of riparian habitats and more abundant food supply linked to more diverse and intense human influences in a suburban zone. Both indirect (NMDS) and direct ordination (CCA) revealed remarkably large number of evenly important factors underlying riparian bird-habitat interactions. It suggests considerable environmental heterogeneity and complexity of these interactions as a likely outcome of long and complex disturbance and alteration histories of the area. Yet structure and relative importance of first two gradients (longitudinal and lateral linkages) remains simple and stable, complying well with predictions of river continuum concept and stream ecosystem theory. Of the nine statistically significant variables most strongly correlated with first two CCA axes, percentages of Helianthus tuberosus, footpaths, fields, Calystegia sepium and steep banks uphold our hypotheses predicting significant effects of invasive species, visitor disturbances, agricultural land use and unaltered river banks/bed on bird community composition and structure. A small but significant contribution of patch size standard

  7. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors.

    Science.gov (United States)

    Marek, Michal V; Janouš, Dalibor; Taufarová, Klára; Havránková, Kateřina; Pavelka, Marian; Kaplan, Věroslav; Marková, Irena

    2011-05-01

    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Nitrogen and Carbon Cycling in a Grassland Community Ecosystem as Affected by Elevated Atmospheric CO2

    Directory of Open Access Journals (Sweden)

    H. A. Torbert

    2012-01-01

    Full Text Available Increasing global atmospheric carbon dioxide (CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystems and the long-term storage of carbon (C and nitrogen (N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L. Willd (Huisache. Seedlings of Acacia along with grass species were grown for 13 months at CO2 concentrations of 385 (ambient, 690, and 980 μmol mol−1. Elevated CO2 increased both C and N inputs from plant growth which would result in higher soil C from litter fall, root turnover, and excretions. Results from the incubation indicated an initial (20 days decrease in N mineralization which resulted in no change in C mineralization. However, after 40 and 60 days, an increase in both C and N mineralization was observed. These increases would indicate that increases in soil C storage may not occur in grass ecosystems that are invaded with Acacia over the long term.

  9. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    Directory of Open Access Journals (Sweden)

    Pablo Rodríguez-Lozano

    Full Text Available Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1 leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2 triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel, conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

  10. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    Science.gov (United States)

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

  11. Impacts of Diffuse Radiation on Light Use Efficiency across Terrestrial Ecosystems Based on Eddy Covariance Observation in China

    Science.gov (United States)

    Huang, Kun; Wang, Shaoqiang; Zhou, Lei; Wang, Huimin; Zhang, Junhui; Yan, Junhua; Zhao, Liang; Wang, Yanfen; Shi, Peili

    2014-01-01

    Ecosystem light use efficiency (LUE) is a key factor of production models for gross primary production (GPP) predictions. Previous studies revealed that ecosystem LUE could be significantly enhanced by an increase on diffuse radiation. Under large spatial heterogeneity and increasing annual diffuse radiation in China, eddy covariance flux data at 6 sites across different ecosystems from 2003 to 2007 were used to investigate the impacts of diffuse radiation indicated by the cloudiness index (CI) on ecosystem LUE in grassland and forest ecosystems. Our results showed that the ecosystem LUE at the six sites was significantly correlated with the cloudiness variation (0.24≤R2≤0.85), especially at the Changbaishan temperate forest ecosystem (R2 = 0.85). Meanwhile, the CI values appeared more frequently between 0.8 and 1.0 in two subtropical forest ecosystems (Qianyanzhou and Dinghushan) and were much larger than those in temperate ecosystems. Besides, cloudiness thresholds which were favorable for enhancing ecosystem carbon sequestration existed at the three forest sites, respectively. Our research confirmed that the ecosystem LUE at the six sites in China was positively responsive to the diffuse radiation, and the cloudiness index could be used as an environmental regulator for LUE modeling in regional GPP prediction. PMID:25393629

  12. Effects of contemporary land-use and land-cover change on the carbon balance of terrestrial ecosystems in the United States

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Rayfield, Bronwyn; Sherba, Jason; Hawbaker, Todd J.; Zhu, Zhiliang; Selmants, Paul C.; Loveland, Thomas R.

    2018-04-01

    Changes in land use and land cover (LULC) can have profound effects on terrestrial carbon dynamics, yet their effects on the global carbon budget remain uncertain. While land change impacts on ecosystem carbon dynamics have been the focus of numerous studies, few efforts have been based on observational data incorporating multiple ecosystem types spanning large geographic areas over long time horizons. In this study we use a variety of synoptic-scale remote sensing data to estimate the effect of LULC changes associated with urbanization, agricultural expansion and contraction, forest harvest, and wildfire on the carbon balance of terrestrial ecosystems (forest, grasslands, shrublands, and agriculture) in the conterminous United States (i.e. excluding Alaska and Hawaii) between 1973 and 2010. We estimate large net declines in the area of agriculture and forest, along with relatively small increases in grasslands and shrublands. The largest net change in any class was an estimated gain of 114 865 km2 of developed lands, an average rate of 3282 km2 yr‑1. On average, US ecosystems sequestered carbon at an annual rate of 254 Tg C yr‑1. In forest lands, the net sink declined by 35% over the study period, largely a result of land-use legacy, increasing disturbances, and reductions in forest area due to land use conversion. Uncertainty in LULC change data contributed to a ~16% margin of error in the annual carbon sink estimate prior to 1985 (approximately ±40 Tg C yr‑1). Improvements in LULC and disturbance mapping starting in the mid-1980s reduced this uncertainty by ~50% after 1985. We conclude that changes in LULC are a critical component to understanding ecosystem carbon dynamics, and continued improvements in detection, quantification, and attribution of change have the potential to significantly reduce current uncertainties.

  13. Effects of contemporary land-use and land-cover change on the carbon balance of terrestrial ecosystems in the United States

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Rayfield, Bronwyn; Sherba, Jason; Hawbaker, Todd J.; Zhu, Zhiliang; Selmants, Paul; Loveland, Thomas R.

    2018-01-01

    Changes in land use and land cover (LULC) can have profound effects on terrestrial carbon dynamics, yet their effects on the global carbon budget remain uncertain. While land change impacts on ecosystem carbon dynamics have been the focus of numerous studies, few efforts have been based on observational data incorporating multiple ecosystem types spanning large geographic areas over long time horizons. In this study we use a variety of synoptic-scale remote sensing data to estimate the effect of LULC changes associated with urbanization, agricultural expansion and contraction, forest harvest, and wildfire on the carbon balance of terrestrial ecosystems (forest, grasslands, shrublands, and agriculture) in the conterminous United States (i.e. excluding Alaska and Hawaii) between 1973 and 2010. We estimate large net declines in the area of agriculture and forest, along with relatively small increases in grasslands and shrublands. The largest net change in any class was an estimated gain of 114 865 km2 of developed lands, an average rate of 3282 km2 yr−1. On average, US ecosystems sequestered carbon at an annual rate of 254 Tg C yr−1. In forest lands, the net sink declined by 35% over the study period, largely a result of land-use legacy, increasing disturbances, and reductions in forest area due to land use conversion. Uncertainty in LULC change data contributed to a ~16% margin of error in the annual carbon sink estimate prior to 1985 (approximately ±40 Tg C yr−1). Improvements in LULC and disturbance mapping starting in the mid-1980s reduced this uncertainty by ~50% after 1985. We conclude that changes in LULC are a critical component to understanding ecosystem carbon dynamics, and continued improvements in detection, quantification, and attribution of change have the potential to significantly reduce current uncertainties.

  14. [Net photosynthesis and its affecting factors in a tropical seasonal rainforest ecosystem in southwest China].

    Science.gov (United States)

    Song, Qing-hai; Zhang, Yi-ping; Tan, Zheng-hong; Zhang, Lei-ming; Yang, Zhen; Zhao, Shuang-ju; Sun, Xiao-min

    2010-12-01

    By using eddy covariance technique, this paper quantitatively analyzed the photosynthetic characteristics of tropical seasonal rainforest ecosystem and related environmental controlling factors in Xishuangbanna in 2003-2006. In the study period, less interannual difference was observed in the net photosynthesis of the ecosystem, with the maximum photosynthesis rate (P(eco,opt)), respiration at daytime (R(eco,d)), and apparent quantum yield (alpha) averaged by 0.813 mg x m(-2) x s(-1), 0.238 mg x m(-2) x s(-1), and 0.0023 mg x micromol(-1), respectively. As affected by the interaction of air temperature (Ta) and vapor pressure deficit (VPD), the photosynthetic characteristics had some seasonal differences. In rainy season, the ecosystem had the strongest photosynthetic capacity because of the higher precipitation and warmer air temperature; in foggy and cool season, fog drip played an important role in the water relations of plants, and thereby, the ecosystem photosynthetic capacity was still higher; in dry and hot season, due to the limited precipitation and high temperature, the Ta and VPD increased, inducing a decrease of ecosystem alpha and P(eco,opt). The net CO2 exchange of the ecosystem strongly depended on the Ta above 20 degrees C and the VPD above 1 kPa.

  15. How does vineyard management intensity affect ecosystem services and disservices - insights from a meta-analysis

    Science.gov (United States)

    Winter, Silvia; Zaller, Johann G.; Kratschmer, Sophie; Pachinger, Bärbel; Strauss, Peter; Bauer, Thomas; Paredes, Daniel; Gómez, José A.; Guzmán, Gema; Landa, Blanca; Nicolai, Annegret; Burel, Francoise; Cluzeau, Daniel; Popescu, Daniela; Bunea, Claudiu-Ioan; Potthoff, Martin; Guernion, Muriel; Batáry, Péter

    2016-04-01

    Viticultural agro-ecosystems provide a range of different ecosystem services which are affected by management decisions of winegrowers. At the global scale, vineyards are often high intensity agricultural systems with bare soil or inter-row vegetation consisting of only a few plant species. These systems primarily aim at optimizing wine production by reducing competition for water and nutrients between grapevines and weeds and by preventing the outbreak of pests and diseases. At the same time, this kind of management is often associated with ecosystem disservices such as high rates of soil erosion, degradation of soil structure and fertility, contamination of groundwater and decline of biodiversity. Recently, several initiatives across the world tried to overcome detrimental effects of that management style by creating biodiversity friendly vineyards. The consequences of establishing divers cover crop mixes or tolerating spontaneous vegetation in vineyards for ecosystem services (including yield) overstretching local case studies has not been investigated yet. This meta-analysis will provide an overview of all published studies comparing the effects of different vineyard management practices on a range of different ecosystem services like biodiversity, pest control, pollination, soil conservation and carbon sequestration. The aggregated effect size will point out which management measures can provide the best overall net sum of ecosystem services. This meta-analysis is part of the transdisciplinary BiodivERsA project VineDivers and will ultimately lead into management and policy recommendations for various stakeholder groups engaged in viticulture.

  16. A strategy to study regional hydrology and terrestrial ecosystem processes using satellite remote sensing, ground-based data and computer modeling

    Science.gov (United States)

    Vorosmarty, C.; Grace, A.; Moore, B.; Choudhury, B.; Willmott, C. J.

    1990-01-01

    A strategy is presented for integrating scanning multichannel microwave radiometer data from the Nimbus-7 satellite with meteorological station records and computer simulations of land surface hydrology, terrestrial nutrient cycling, and trace gas emission. Analysis of the observations together with radiative transfer analysis shows that in the tropics the temporal and spatial variations of the polarization difference are determined primarily by the structure and phenology of vegetation and seasonal inundations of major rivers and wetlands. It is concluded that the proposed surface hydrology model, along with climatological records, and, potentially, 37-GHz data for phenology, will provide inputs to a terrestrial ecosystem model that predicts regional net primary production and CO2 gas exchange.

  17. Ecological risk assessment for the terrestrial ecosystem under chronic radioactive pollution - Ecological risk assessment for the biota on regional radioactive waste storage

    Energy Technology Data Exchange (ETDEWEB)

    Lavrentyeva, G.V.; Synzynys, B.I.; Shoshina, R.R.; Mirzeabasov, O.A. [Obninsk Institute for Nuclear Power Engineering, branch of the National Research Nuclear University MEPhI, Department of Ecology, Studgorodok,1, 249040 Obninsk, Kaluga region (Russian Federation)

    2014-07-01

    Now the methods of ecological regulation of a radiation factor from risk assessment are developed poorly. The paper attempts to assess and forecast the terrestrial ecosystem conditions under chronic ionizing radiation by calculating the critical loads. The paper is aimed at developing a methodology to assess the ecological risk for a terrestrial ecosystem under chronic radioactive pollution in a biotope of a regional radioactive waste storage. Objects and Methods: Biotope monitoring of a radioactive waste storage makes clear that the radioecological situation in this territory is stipulated by technogenic {sup 90}Sr found in soil, ground water and biota. Terrestrial mollusks of a shrubby Snail type (Bradybaena fruticum) were chosen as reference species due to their activity to accumulate {sup 90}Sr in shells and the number of colony-forming soil units (CFU) as reference indices. The number of CFU was determined by inoculation of solid medium. Soil and mollusk samples have been collected at most representative sites identified in the previous studies. To assess {sup 90}Sr content in the samples collected, radiochemical separation was used with further radionuclide activity measurements by a 'BETA-01C' scintillation beta-ray spectrometer according to a standard procedure of {sup 90}Sr content assessment from beta-radiation of its daughter radionuclide {sup 90}Y. Ecological risk was calculated from analyzed critical loads using a 'dose-effect' dependence. Statistical data processing was realized with Excell 2007 and R software programs [R Development Core Team, 2010]. The software R was also used for GIS creation. Results and Discussion: A methodology of ecological risk assessment for the terrestrial ecosystem under chronic radioactive pollution of a biotope near a regional radioactive waste storage has been developed in terms of the critical environmental loads analyzed. It consists of five stages: determination of effect indicators and assessment

  18. Linking the evolution of habitat choice to ecosystem functioning: direct and indirect effects of pond-reproducing fire salamanders on aquatic-terrestrial subsidies.

    Science.gov (United States)

    Reinhardt, Timm; Steinfartz, Sebastian; Paetzold, Achim; Weitere, Markus

    2013-09-01

    Shifts in life history traits and in the behaviour of species can potentially alter ecosystem functioning. The reproduction of the central European fire salamander (Salamandra salamandra), which usually deposits its larvae in first-order streams, in small pool and pond-like habitats, is an example of a recent local adaptation in this species. Here we aimed to quantify the direct and indirect effects of the predatory larvae on the aquatic food webs in the ponds and on the flux of matter between the ponds and adjacent terrestrial habitats. Our estimates are based on biomass data of the present pond fauna as well as on the analysis of stomach content data, growth rates and population dynamics of the salamander larvae in pond habitats. By their deposition of larvae in early spring, female fire salamanders import between 0.07 and 2.86 g dry mass m(-2) larval biomass into the ponds. Due to high mortality rates in the larval phase and the relatively small size at metamorphosis of the pond-adapted salamanders compared to stream-adapted ones, the biomass export of the metamorphosed salamanders clearly falls below the initial biomass import. Catastrophic events such as high water temperatures and low oxygen levels may even occasionally result in mass mortalities of salamander larvae and thus in a net 100 % import of the salamander biomass into the pond food webs. Indirect effects further accelerate this net import of matter into the aquatic habitat, e.g. the feeding of salamanders on aquatic insect larvae with the emergence of terrestrial adults-thus preventing export-and on terrestrial organisms that fall on the water surface (supporting import). This study demonstrates that the adaptation of salamanders to pond reproduction can alter food web linkages across ecosystem boundaries by enhancing the flux of materials and energy from terrestrial (i.e. forest) to the aquatic (i.e. pond) habitat.

  19. Drought dominates the interannual variability in global terrestrial net primary production by controlling semi-arid ecosystems

    OpenAIRE

    Ling Huang; Bin He; Aifang Chen; Haiyan Wang; Junjie Liu; Aifeng Lű; Ziyue Chen

    2016-01-01

    Drought is a main driver of interannual variation in global terrestrial net primary production. However, how and to what extent drought impacts global NPP variability is unclear. Based on the multi-timescale drought index SPEI and a satellite-based annual global terrestrial NPP dataset, we observed a robust relationship between drought and NPP in both hemispheres. In the Northern Hemisphere, the annual NPP trend is driven by 19-month drought variation, whereas that in the Southern Hemisphere ...

  20. Understanding the time-lag effect of terrestrial ecosystem response to drought: a regional case study of the 2000s Millennium Drought in Australia

    Science.gov (United States)

    Zhao, M.; A, G.; Velicogna, I.; Kimball, J. S.

    2016-12-01

    Drought is one of the major drivers of the reduction in terrestrial ecosystem productivity. Ecosystem productivity may not primarily be driven by present moisture conditions. Instead, earlier drought conditions may have the largest impact on vegetation growth. We investigate this time-lag effect in Australia by comparing MODIS NDVI data with multiple drought metrics that are sensitive to water deficits at different soil depths. These metrics include 1) soil moisture (SM) from microwave satellite-retrievals that is sensitive to top-centimeter SM variations; 2) the Palmer drought severity index (PDSI) which is sensitive to atmosphere moisture demand and shallow-depth ( 1 meter) SM changes; 3) the newly developed GRACE drought severity index (GRACE-DSI) that is sensitive to changes in overall terrestrial water storage component of the hydrologic cycle and complements satellite SM observations and the PDSI by providing information about deep groundwater storage changes. We quantify the temporal lags between NDVI and these drought metrics during 2002-2014. We find that the NDVI closely evolves with the GRACE-DSI but lags 1-3 months behind the PDSI and satellite-retrievals of SM in western Australia. This pattern however is reverse in eastern Australia. These contrasting NDVI response patterns indicate that vegetation in western Australia is more sensitive to water storage in relatively deeper soil depths than vegetation in the east. This suggests that, in western Australia, vegetation might experience a protracted recovery period after extreme drought since, usually, moisture recharge in deeper soil depths takes a relatively longer period. We conclude that the time-lag effect in Australia is associated with the relative depth of SM to which vegetation is most sensitive. We suggest that characterizing the relative vegetation moisture sensitive depth at the global scale is important for understanding the nature and pace of terrestrial ecosystem recovery from extreme

  1. Application of Terrestrial Ecosystem Monitoring under the CAFF Circumpolar Biodiversity Monitoring Program: Designing and Implementing Terrestrial Monitoring to Establish the Canadian High Arctic Research Station as a Flagship Arctic Environmental Monitoring Site

    Science.gov (United States)

    McLennan, D.; Kehler, D.

    2016-12-01

    The Canadian High Arctic Research Station (CHARS) is scheduled for completion in July 2017 and is the northern science component of Polar Knowledge Canada (POLAR). A mandated goal for POLAR is to establish the adjacent Experimental and Reference Area (ERA) as an Arctic Flagship monitoring site that will track change in Arctic terrestrial, freshwater and marine ecosystems. Situated in the community of Cambridge Bay, CHARS provides the opportunity to draw on the Indigenous Knowledge of local residents to help design and conduct the monitoring, and to operate 12 months a year. Monitoring at CHARS will be linked to networks nationally and internationally, and is being designed so that change in key indicators can be understood in terms of drivers and processes, modeled and scaled up regionally, and used to predict important changes in critical indicators. As a partner in the Circumpolar Biodiversity Monitoring Program (CBMP), the monitoring design for terrestrial ecosystems follows approaches outlined by the CBMP Terrestrial Expert Monitoring Group, who have listed key monitoring questions and identified a list of important Focal Ecosystem Components (FECs). To link drivers to FECs we are proposing a multi-scaled approach: 1) an Intensive Monitoring Area to establish replicated monitoring plots that track change in snow depth and condition, active layer depth, soil temperature, soil moisture, and soil solution chemistry that are spatially and temporally linked to changes in microbiological activity, CO2/CH4 net ecosystem flux, vegetation relative frequency, species composition, growth and foliar nutrient concentration, arthropod abundance, lemming abundance and health, and shorebird/songbird abundance and productivity. 2) These intensive observations are supported by watershed scale measures that will monitor, during the growing season, lemming winter nest abundance, songbird, shorebird and waterfowl staging and nesting, and other observations; in the winter we will

  2. Current and future carbon budget at Takayama site, Japan, evaluated by a regional climate model and a process-based terrestrial ecosystem model.

    Science.gov (United States)

    Kuribayashi, Masatoshi; Noh, Nam-Jin; Saitoh, Taku M; Ito, Akihiko; Wakazuki, Yasutaka; Muraoka, Hiroyuki

    2017-06-01

    Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO 2 ) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO 2 . In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ecosystem model simulation for canopy phenology and carbon budget such as gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) of a deciduous forest in Japan. Then, we simulated the future (around 2085) changes in canopy phenology and carbon budget of the forest by incorporating high-resolution meteorological data downscaled by a regional climate model. The ecosystem model overestimated GPP and ER when we inputted low-resolution data, which have warming biases over mountainous landscape. But, it reproduced canopy phenology and carbon budget well, when we inputted high-resolution data. Under the future climate, earlier leaf expansion and delayed leaf fall by about 10 days compared with the present state was simulated, and also, GPP, ER and NEP were estimated to increase by 25.2%, 23.7% and 35.4%, respectively. Sensitivity analysis showed that the increase of NEP in June and October would be mainly caused by rising temperature, whereas that in July and August would be largely attributable to CO 2 fertilization. This study suggests that the downscaling of future climate data enable us to project more reliable carbon budget of forest ecosystem in mountainous landscape than the low-resolution simulation due to the better predictions of leaf expansion and shedding.

  3. Effect of trophic level on the radiocesium frequency distribution in aquatic and terrestrial ecosystems at Chornobyl and nuclear sites in the United States

    International Nuclear Information System (INIS)

    Smith, Michael H.; Tsyusko-Omeltchenko, Olga; Oleksyk, Taras K.

    2003-01-01

    There are significant linear relationship between the standard deviation and the mean of radiocesium concentration for samples of soils, sediments, plants, and animals from Chornobyl and nuclear sites in the United States. The universal occurrence of this relationship in all types of samples suggests that a non-normal frequency distribution should be expected. The slopes of these relationships are similar for fish and mammals from the two regions of the world but those for plants are not. The slopes for plants are similar for aquatic and terrestrial ecosystems within each region. We hypothesize that there are relationships between the four moments of the frequency distribution of radiocesium (mean, variance, skewness, and kurtosis), and that these relationships are caused by the functional properties of the organisms and other characteristics of the ecosystem. The way in which radiocesium was distributed across the landscape does not seem to be a factor in determining the form of the frequency distribution. (author)

  4. Terrestrial ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The main effort of the Terrestrial Ecology Division has been redirected to a comprehensive study of the Espiritu Santo Drainage Basin located in northeastern Puerto Rico. The general objective are to provide baseline ecological data for future environmental assessment studies at the local and regional levels, and to provide through an ecosystem approach data for the development of management alternatives for the wise utilization of energy, water, and land resources. The interrelationships among climate, vegetation, soils, and man, and their combined influence upon the hydrologic cycle will be described and evaluated. Environmental management involves planning and decision making, and both require an adequate data base. At present, little is known about the interworkings of a complete, integrated system such as a drainage basin. A literature survey of the main research areas confirmed that, although many individual ecologically oriented studies have been carried out in a tropical environment, few if any provide the data base required for environmental management. In view of rapidly changing socio-economic conditions and natural resources limitations, management urgently requires data from these systems: physical (climatological), biological, and cultural. This integrated drainage basin study has been designed to provide such data. The scope of this program covers the hydrologic cycle as it is affected by the interactions of the physical, biological, and cultural systems

  5. Wild food in Europe: a synthesis of knowledge and data of terrestrial wild food as an ecosystem service

    NARCIS (Netherlands)

    Schulp, C.J.E.; Thuiller, W.; Verburg, P.H.

    2014-01-01

    Wild food is an iconic ecosystem service that receives little attention in quantifying, valuating and mapping studies, due to the perceived low importance or due to lack of data. Here, we synthesize available data on the importance of wild food as ecosystem service, its spatial distribution and

  6. Linking terrestrial and estuarine ecosystems: Organic matter sources supporting the high secondary production of a non-indigenous bivalve

    Science.gov (United States)

    The Asian clam Corbicula fluminea is one of the most pervasive species in freshwater ecosystems. Our objective was to characterize the trophic interactions of C. fluminea in the Minho river estuary (NW-Iberian Peninsula, Europe), an estuarine ecosystem in which C. fluminea presen...

  7. Model estimates of net primary productivity, evaportranspiration, and water use efficiency in the terrestrial ecosystems of the southern United States

    Science.gov (United States)

    Hanqin Tian; Guangsheng Chen; Mingliang Liu; Chi Zhang; Ge Sun; Chaoqun Lu; Xiaofeng Xu; Wei Ren; Shufen Pan; Arthur. Chappelka

    2010-01-01

    The effects of global change on ecosystem productivity and water resources in the southern United States (SUS), a traditionally ‘water-rich’ region and the ‘timber basket’ of the country, are not well quantified. We carried out several simulation experiments to quantify ecosystem net primary productivity (NPP), evapotranspiration (ET)...

  8. Invasive plants have different effects on trophic structure of green and brown food webs in terrestrial ecosystems: a meta-analysis.

    Science.gov (United States)

    McCary, Matthew A; Mores, Robin; Farfan, Monica A; Wise, David H

    2016-03-01

    Although invasive plants are a major source of terrestrial ecosystem degradation worldwide, it remains unclear which trophic levels above the base of the food web are most vulnerable to plant invasions. We performed a meta-analysis of 38 independent studies from 32 papers to examine how invasive plants alter major groupings of primary and secondary consumers in three globally distributed ecosystems: wetlands, woodlands and grasslands. Within each ecosystem we examined if green (grazing) food webs are more sensitive to plant invasions compared to brown (detrital) food webs. Invasive plants have strong negative effects on primary consumers (detritivores, bacterivores, fungivores, and/or herbivores) in woodlands and wetlands, which become less abundant in both green and brown food webs in woodlands and green webs in wetlands. Plant invasions increased abundances of secondary consumers (predators and/or parasitoids) only in woodland brown food webs and green webs in wetlands. Effects of invasive plants on grazing and detrital food webs clearly differed between ecosystems. Overall, invasive plants had the most pronounced effects on the trophic structure of wetlands and woodlands, but caused no detectable changes to grassland trophic structure. © 2016 John Wiley & Sons Ltd/CNRS.

  9. Does litter size variation affect models of terrestrial carnivore extinction risk and management?

    Directory of Open Access Journals (Sweden)

    Eleanor S Devenish-Nelson

    Full Text Available Individual variation in both survival and reproduction has the potential to influence extinction risk. Especially for rare or threatened species, reliable population models should adequately incorporate demographic uncertainty. Here, we focus on an important form of demographic stochasticity: variation in litter sizes. We use terrestrial carnivores as an example taxon, as they are frequently threatened or of economic importance. Since data on intraspecific litter size variation are often sparse, it is unclear what probability distribution should be used to describe the pattern of litter size variation for multiparous carnivores.We used litter size data on 32 terrestrial carnivore species to test the fit of 12 probability distributions. The influence of these distributions on quasi-extinction probabilities and the probability of successful disease control was then examined for three canid species - the island fox Urocyon littoralis, the red fox Vulpes vulpes, and the African wild dog Lycaon pictus. Best fitting probability distributions differed among the carnivores examined. However, the discretised normal distribution provided the best fit for the majority of species, because variation among litter-sizes was often small. Importantly, however, the outcomes of demographic models were generally robust to the distribution used.These results provide reassurance for those using demographic modelling for the management of less studied carnivores in which litter size variation is estimated using data from species with similar reproductive attributes.

  10. Uptake of Cadmium, Copper, Lead, and Zinc from Sediments by an Aquatic Macrophyte and by Terrestrial Arthropods in a Freshwater Wetland Ecosystem.

    Science.gov (United States)

    Kim, Heung-Tae; Kim, Jae Geun

    2016-08-01

    The objective of this study was to investigate trace-metal [cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn)] biotransference and biomagnification in terrestrial biota at different trophic levels (primary producer-top predator) of a wetland ecosystem. We investigated whether metal concentrations in the sediment are reflected in terrestrial arthropods and aquatic plants. We sampled the floating-leaved plant Trapa japonica; its species-specific primary consumer, the leaf beetle Galerucella nipponensis; and two predatory arthropods (the water strider Gerris sp. and the wolf spider Arctosa sp.) from three wetlands with different sedimentary metal concentrations. The δ(13)C and δ(15)N signatures in the trophic link between the plants and the leaf beetles supported the specificity of their feeding relationship. The stable isotope signatures indicate that the leaf beetle could be an important link in the trophic transfer of the metals. Transference factors (TFs) were 1 for all biota, and the concentrations were positively correlated with the trophic levels. Thus, there may be Cu and Zn biomagnification in the arthropods. We noted TF 1 among the arthropods. Therefore, Cd is probably not biomagnified between T. japonica and G. nipponensis, but it might be biomagnified in the arthropods. The metal burden in terrestrial arthropods may also be influenced by uptake from the sediment by aquatic plants.

  11. Forestry, ecosystems, and wildlife: The differences are in the details

    Science.gov (United States)

    Linda Joyce

    2008-01-01

    Climate affects all terrestrial and aquatic ecosystems in Colorado, and over the long term, plants and animals adapt. In the short term, fires, increased attacks by insects and invasive plant species, and higher temperatures are changing familiar landscapes.

  12. Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min; Zhuang, Qianlai; Cook, D.; Coulter, Richard L.; Pekour, Mikhail S.; Scott, Russell L.; Munger, J. W.; Bible, Ken

    2011-08-31

    Satellite remote sensing provides continuous temporal and spatial information of terrestrial ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical models, such as the Terrestrial Ecosystem Model (TEM), should provide a more adequate quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI), Land Surface Water Index (LSWI) and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary production (GPP) modeling in TEM by incorporating EVI and LSWI to account for the effects of the changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and verify the new version of TEM with eddy flux data. We then apply the model to the conterminous United States over the period 2000-2005 at a 0.05-0.05 spatial resolution. We find that the new version of TEM made improvement over the previous version and generally captured the expected temporal and spatial patterns of regional carbon dynamics. We estimate that regional GPP is between 7.02 and 7.78 PgC yr{sup -1} and net primary production (NPP) ranges from 3.81 to 4.38 Pg Cyr{sup -1} and net ecosystem production (NEP) varies within 0.08- 0.73 PgC yr{sup -1} over the period 2000-2005 for the conterminous United States. The uncertainty due to parameterization is 0.34, 0.65 and 0.18 PgC yr{sup -1} for the regional estimates of GPP, NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a new independent and more adequate measure of carbon fluxes for the conterminous United States, which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon management and climate.

  13. Quantification of Terrestrial Ecosystem Carbon Dynamics in the Conterminous United States Combining a Process-Based Biogeochemical Model and MODIS and AmeriFlux data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min; Zhuang, Qianlai; Cook, David R.; Coulter, Richard L.; Pekour, Mikhail S.; Scott, Russell L.; Munger, J. W.; Bible, Ken

    2011-09-21

    Satellite remote sensing provides continuous temporal and spatial information of terrestrial 24 ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical 25 models, such as the Terrestrial Ecosystem Model (TEM), should provide a more adequate 26 quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution 27 Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI), Land Surface Water Index 28 (LSWI) and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary 29 production (GPP) modeling in TEM by incorporating EVI and LSWI to account for the effects of the 30 changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and 31 verify the new version of TEM with eddy flux data. We then apply the model to the conterminous 32 United States over the period 2000-2005 at a 0.05o ×0.05o spatial resolution. We find that the new 33 version of TEM generally captured the expected temporal and spatial patterns of regional carbon 34 dynamics. We estimate that regional GPP is between 7.02 and 7.78 Pg C yr-1 and net primary 35 production (NPP) ranges from 3.81 to 4.38 Pg C yr-1 and net ecosystem production (NEP) varies 36 within 0.08-0.73 Pg C yr-1 over the period 2000-2005 for the conterminous United States. The 37 uncertainty due to parameterization is 0.34, 0.65 and 0.18 Pg C yr-1 for the regional estimates of GPP, 38 NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 39 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a 40 new independent and more adequate measure of carbon fluxes for the conterminous United States, 41 which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon 42 management and climate.

  14. Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

    Directory of Open Access Journals (Sweden)

    M. Chen

    2011-09-01

    Full Text Available Satellite remote sensing provides continuous temporal and spatial information of terrestrial ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical models, such as the Terrestrial Ecosystem Model (TEM, should provide a more adequate quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS Enhanced Vegetation Index (EVI, Land Surface Water Index (LSWI and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary production (GPP modeling in TEM by incorporating EVI and LSWI to account for the effects of the changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and verify the new version of TEM with eddy flux data. We then apply the model to the conterminous United States over the period 2000–2005 at a 0.05° × 0.05° spatial resolution. We find that the new version of TEM made improvement over the previous version and generally captured the expected temporal and spatial patterns of regional carbon dynamics. We estimate that regional GPP is between 7.02 and 7.78 Pg C yr−1 and net primary production (NPP ranges from 3.81 to 4.38 Pg C yr−1 and net ecosystem production (NEP varies within 0.08–0.73 Pg C yr−1 over the period 2000–2005 for the conterminous United States. The uncertainty due to parameterization is 0.34, 0.65 and 0.18 Pg C yr−1 for the regional estimates of GPP, NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a new independent and more adequate measure of carbon fluxes for the conterminous United States, which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon management and climate.

  15. The Phanerozoic diversification of silica-cycling testate amoebae and its possible links to changes in terrestrial ecosystems

    Science.gov (United States)

    Bosak, Tanja; Lara, Enrique; Mitchell, Edward A.D.

    2015-01-01

    The terrestrial cycling of Si is thought to have a large influence on the terrestrial and marine primary production, as well as the coupled biogeochemical cycles of Si and C. Biomineralization of silica is widespread among terrestrial eukaryotes such as plants, soil diatoms, freshwater sponges, silicifying flagellates and testate amoebae. Two major groups of testate (shelled) amoebae, arcellinids and euglyphids, produce their own silica particles to construct shells. The two are unrelated phylogenetically and acquired biomineralizing capabilities independently. Hyalosphenids, a group within arcellinids, are predators of euglyphids. We demonstrate that hyalosphenids can construct shells using silica scales mineralized by the euglyphids. Parsimony analyses of the current hyalosphenid phylogeny indicate that the ability to “steal” euglyphid scales is most likely ancestral in hyalosphenids, implying that euglyphids should be older than hyalosphenids. However, exactly when euglyphids arose is uncertain. Current fossil record contains unambiguous euglyphid fossils that are as old as 50 million years, but older fossils are scarce and difficult to interpret. Poor taxon sampling of euglyphids has also prevented the development of molecular clocks. Here, we present a novel molecular clock reconstruction for arcellinids and consider the uncertainties due to various previously used calibration points. The new molecular clock puts the origin of hyalosphenids in the early Carboniferous (∼370 mya). Notably, this estimate coincides with the widespread colonization of land by Si-accumulating plants, suggesting possible links between the evolution of Arcellinid testate amoebae and the expansion of terrestrial habitats rich in organic matter and bioavailable Si. PMID:26734499

  16. The Phanerozoic diversification of silica-cycling testate amoebae and its possible links to changes in terrestrial ecosystems

    Directory of Open Access Journals (Sweden)

    Daniel J.G. Lahr

    2015-09-01

    Full Text Available The terrestrial cycling of Si is thought to have a large influence on the terrestrial and marine primary production, as well as the coupled biogeochemical cycles of Si and C. Biomineralization of silica is widespread among terrestrial eukaryotes such as plants, soil diatoms, freshwater sponges, silicifying flagellates and testate amoebae. Two major groups of testate (shelled amoebae, arcellinids and euglyphids, produce their own silica particles to construct shells. The two are unrelated phylogenetically and acquired biomineralizing capabilities independently. Hyalosphenids, a group within arcellinids, are predators of euglyphids. We demonstrate that hyalosphenids can construct shells using silica scales mineralized by the euglyphids. Parsimony analyses of the current hyalosphenid phylogeny indicate that the ability to “steal” euglyphid scales is most likely ancestral in hyalosphenids, implying that euglyphids should be older than hyalosphenids. However, exactly when euglyphids arose is uncertain. Current fossil record contains unambiguous euglyphid fossils that are as old as 50 million years, but older fossils are scarce and difficult to interpret. Poor taxon sampling of euglyphids has also prevented the development of molecular clocks. Here, we present a novel molecular clock reconstruction for arcellinids and consider the uncertainties due to various previously used calibration points. The new molecular clock puts the origin of hyalosphenids in the early Carboniferous (∼370 mya. Notably, this estimate coincides with the widespread colonization of land by Si-accumulating plants, suggesting possible links between the evolution of Arcellinid testate amoebae and the expansion of terrestrial habitats rich in organic matter and bioavailable Si.

  17. Quantifying and Monetizing Potential Climate Change Policy Impacts on Terrestrial Ecosystem Carbon Storage and Wildfires in the United States

    Science.gov (United States)

    This paper quantifies and monetizes climate change impacts on carbon stored in terrestrial vegetation and wildfire incidence in the contiguous United States to assess the benefits of alternative mitigation policies. The MC-1 dynamic global vegetation model was used to develop int...

  18. The rise of fire: Fossil charcoal in late Devonian marine shales as an indicator of expanding terrestrial ecosystems, fire, and atmospheric change

    Science.gov (United States)

    Rimmer, Susan M.; Hawkins, Sarah J.; Scott, Andrew C.; Cressler, Walter L.

    2015-01-01

    Fossil charcoal provides direct evidence for fire events that, in turn, have implications for the evolution of both terrestrial ecosystems and the atmosphere. Most of the ancient charcoal record is known from terrestrial or nearshore environments and indicates the earliest occurrences of fire in the Late Silurian. However, despite the rise in available fuel through the Devonian as vascular land plants became larger and trees and forests evolved, charcoal occurrences are very sparse until the Early Mississippian where extensive charcoal suggests well-established fire systems. We present data from the latest Devonian and Early Mississippian of North America from terrestrial and marine rocks indicating that fire became more widespread and significant at this time. This increase may be a function of rising O2 levels and the occurrence of fire itself may have contributed to this rise through positive feedback. Recent atmospheric modeling suggests an O2 low during the Middle Devonian (around 17.5%), with O2 rising steadily through the Late Devonian and Early Mississippian (to 21–22%) that allowed for widespread burning for the first time. In Devonian-Mississippian marine black shales, fossil charcoal (inertinite) steadily increases up-section suggesting the rise of widespread fire systems. There is a concomitant increase in the amount of vitrinite (preserved woody and other plant tissues) that also suggests increased sources of terrestrial organic matter. Even as end Devonian glaciation was experienced, fossil charcoal continued to be a source of organic matter being introduced into the Devonian oceans. Scanning electron and reflectance microscopy of charcoal from Late Devonian terrestrial sites indicate that the fires were moderately hot (typically 500–600 °C) and burnt mainly surface vegetation dominated by herbaceous zygopterid ferns and lycopsids, rather than being produced by forest crown fires. The occurrence and relative abundance of fossil charcoal in

  19. Evaluating the effects of future climate change and elevated CO2 on the water use efficiency in terrestrial ecosystems of China

    Science.gov (United States)

    Zhu, Q.; Jiang, H.; Peng, C.; Liu, J.; Wei, X.; Fang, X.; Liu, S.; Zhou, G.; Yu, S.

    2011-01-01

    Water use efficiency (WUE) is an important variable used in climate change and hydrological studies in relation to how it links ecosystem carbon cycles and hydrological cycles together. However, obtaining reliable WUE results based on site-level flux data remains a great challenge when scaling up to larger regional zones. Biophysical, process-based ecosystem models are powerful tools to study WUE at large spatial and temporal scales. The Integrated BIosphere Simulator (IBIS) was used to evaluate the effects of climate change and elevated CO2 concentrations on ecosystem-level WUE (defined as the ratio of gross primary production (GPP) to evapotranspiration (ET)) in relation to terrestrial ecosystems in China for 2009–2099. Climate scenario data (IPCC SRES A2 and SRES B1) generated from the Third Generation Coupled Global Climate Model (CGCM3) was used in the simulations. Seven simulations were implemented according to the assemblage of different elevated CO2 concentrations scenarios and different climate change scenarios. Analysis suggests that (1) further elevated CO2concentrations will significantly enhance the WUE over China by the end of the twenty-first century, especially in forest areas; (2) effects of climate change on WUE will vary for different geographical regions in China with negative effects occurring primarily in southern regions and positive effects occurring primarily in high latitude and altitude regions (Tibetan Plateau); (3) WUE will maintain the current levels for 2009–2099 under the constant climate scenario (i.e. using mean climate condition of 1951–2006 and CO2concentrations of the 2008 level); and (4) WUE will decrease with the increase of water resource restriction (expressed as evaporation ratio) among different ecosystems.

  20. Critical levels and loads of atmospheric pollutants for terrestrial and aquatic ecosystems. The emergence of a scientific concept. Application potentials and their limits

    International Nuclear Information System (INIS)

    Landmann, G.

    1993-01-01

    The 'critical loads and levels' are defined as the highest atmospheric deposition rate or concentration of a gaseous pollutant, respectively, that will not cause harmful effects on sensitive elements of an ecosystem. The recent emergence of the concept of critical loads and levels is described, from the first explicit mention in 1986 to the production of the first European maps in 1991. The difficulties linked to the definition of the concept and to its english-derived terminology are discussed. The main approaches used for assessing critical loads and levels are briefly described. Important research is developed under the auspices of the Convention of Geneva (Long Range Transboundary Air Pollution Transport, UN-ECE), arising from intensive studies which have been carried out on the effects of air pollution on terrestrial and aquatic ecosystems for the past ten or fifteen years. Current knowledge is summarized, as well as the remaining gaps (and questions) which hinder the calculation of the critical thresholds. Finally, beyond the fundamental relevance of this scientifically sound and easily understood concept, its limits are pointed out. In brief, the 'critical loads and levels' concept is attractive and motivating to many scientists: it implies to apply an integrated and finalized approach, favors the prospecting of poorly known ecosystems and regions, and represents an interesting interface with decision makers

  1. Loss of rare fish species from tropical floodplain food webs affects community structure and ecosystem multifunctionality in a mesocosm experiment.

    Science.gov (United States)

    Pendleton, Richard M; Hoeinghaus, David J; Gomes, Luiz C; Agostinho, Angelo A

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  2. Loss of rare fish species from tropical floodplain food webs affects community structure and ecosystem multifunctionality in a mesocosm experiment.

    Directory of Open Access Journals (Sweden)

    Richard M Pendleton

    Full Text Available Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across

  3. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  4. How do land management practices affect net ecosystem CO2 exchange of an invasive plant infestation?

    Science.gov (United States)

    Sonnentag, O.; Detto, M.; Runkle, B.; Kelly, M.; Baldocchi, D. D.

    2009-12-01

    Ecosystem gas and energy exchanges of invasive plant infestations under different land management practices have been subject of few studies and thus little is known. Our goal is to characterize seasonal changes in net ecosystem CO2 exchange (NEE) through the processes of photosynthesis (GEP) and ecosystem respiration (Reco) of a grassland used as pasture yet infested by perennial pepperweed (Lepidium latifolium) in California’s Sacramento-San Joaquin River Delta. We analyze eddy-covariance supported by environmental and canopy-scale hyperspectral reflectance measurements acquired in 2007-2009. Our study covers three summer drought periods with slightly different land management practices. Over the study period the site was subject to year-round grazing, and in 2008 the site was additionally mowed. Specific questions we address are a) how does pepperweed flowering affect GEP, b) does a mowing event affect NEE mainly through GEP or Reco, and c) can the combined effects of phenology and mowing on pepperweed NEE potentially be tracked using routinely applied remote sensing techniques? Preliminary results indicate that pepperweed flowering drastically decreases photosynthetic CO2 uptake due to shading by the dense arrangement of white flowers at the canopy top, causing the infestation to be almost CO2 neutral. In contrast, mowing causes the infestation to act as moderate net CO2 sink, mainly due to increased CO2 uptake during regrowth. We demonstrate that spectral regions other than commonly-used red and near-infrared might be more promising for pepperweed monitoring because of its spectral uniqueness during the flowering phase. Our results have important implications for land-use land-cover (LULC) change studies when biological invasions and their management alter ecosystem structure and functioning but not necessarily the respective LULC class.

  5. Heat Transfer Processes for the Thermal Energy Balance of Organisms. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Stevenson, R. D.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module describes heat transfer processes involved in the exchange of heat…

  6. Animal Thermoregulation and the Operative Environmental (Equivalent) Temperature. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Process.

    Science.gov (United States)

    Stevenson, R. D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Thermoregulation is defined as the ability of an organism to modify its body temperature. This…

  7. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    Science.gov (United States)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower animals similar to that of cellulose in plants. Also it's a compound of cell walls of fungi. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. Roots of the plants and root crops contain pectin. Chitin and pectin are widely distributed throughout the natural world. Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems and detailed studies concerning certain abiotic features as pH. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. It is known that ecosystems have their own structure. It is possible to allocate some vertical tiers: phylloplane, litter (soil covering), soil. We investigated chitinolytic and pectinolytic microbial communities dedicated to different layers of the ecosystems. Also it was described depending on pH dominated in certain ecosystem with certain conditions. Quantity of eukaryote and procaryote organisms increased in the test samples with chitin and pectin. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. The variety and abundance of bacteria in the litter samples increased an order of magnitude as compared to other probes. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic

  8. Radioecology of natural systems in Colordao. Fourteenth annual progress report, May 1, 1975--July 31, 1976. [Pu diffusion in terrestrial ecosystems at Rocky Flats Plant

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, F.W.

    1976-08-01

    This report summarizes project activities during the period May 1, 1975 through July 31, 1976. The major study on the distribution and levels of Pu in major components of the terrestrial ecosystem at Rocky Flats was completed. Supportive studies on the ecology and pathology of small mammals and their role in Pu transport were essentially completed as well. Detailed studies on mule deer food habits, population dynamics, and movements at Rocky Flats are progressing. These studies are designed to measure the potential of mule deer in transporting Pu to uncontrolled areas. Alpha autoradiographic studies designed to measure Pu particle size and distribution and spatial patterns in soil were initiated. Field and greenhouse transport pathways from soil to vegetation are in progress and some early results reported. The status of studies on seasonal kinetics of Cs in a montane lake and stable lead geochemistry in an alpine lake watershed are also reported.

  9. Large herbivores affect forest ecosystem functions by altering the structure of dung beetle communities

    Science.gov (United States)

    Iida, Taichi; Soga, Masashi; Koike, Shinsuke

    2018-04-01

    Dramatic increases in populations of large mammalian herbivores have become a major ecological issue, particularly in the northern hemisphere, due to their substantial impacts on both animal and plant communities through processes such as grazing, browsing, and trampling. However, little is known about the consequences of these population explosions on ecosystem functions. Here, we experimentally investigated how the population density of sika deer (Cervus nippon) in temperate deciduous forest areas in Japan affected the decomposition of mammal dung by dung beetles, which is a key process in forest ecosystems. We measured a range of environmental variables (e.g., vegetation cover, soil hardness) and the dung decomposition rate, measured as the amount of deer dung decomposed during one week, and sampled dung beetles at 16 study sites with three different deer densities (high/intermediate/low). We then used structural equation modeling to investigate the relationships between deer density, environmental variables, the biomass of dung beetles (classified into small or large species), and the dung decomposition rate. We found that the biomass of small species increased with increasing deer density, whereas that of large species was not related to deer density. Furthermore, the dung decomposition rate was positively related to the biomass of small species but unrelated to that of large species. Overall, our results showed that an increase in deer density affects the decomposition rate of mammal dung by changing the structure of dung beetle communities (i.e., increasing the number of small dung beetles). Such an understanding of how increases in large herbivore populations affect ecosystem functions is important for accurately evaluating the ecological consequences of their overabundance and ultimately managing their populations appropriately.

  10. Analysis of chemical factors affecting marine ecosystem around nuclear power plant

    International Nuclear Information System (INIS)

    Chun, Kwan Sik; Choi, Yoon Dong; Chun, Ki Jeong; Kim, Jin Kyu; Jung, Kyeong Chai; Lee, Yeong Keun; Park, Hyo Kook

    1994-06-01

    The ecological data of the coastal area of Youngkwang nuclear power plant from 1987 to 1993 were comprehensively analyzed, and various physical and chemical properties of sea water and sediments were measured. Major factors affecting phytoplankton standing crops were suspended substances, nitrate, and silicate. The contents of iron, chromium, copper, and sulfur in sediments sampled from the discharge channel were slightly higher than those in the other areas. In order to qantify the chemical impacts on marine ecosystem, it is desirable that a systematic survey be made through the whole year cycle to assure the consistency and confidence of the related data. (Author)

  11. Not all ski slopes are created equal: disturbance intensity affects ecosystem properties.

    Science.gov (United States)

    Burt, Jennifer W; Rice, Kevin J

    2009-12-01

    In mountain regions around the world, downhill ski areas represent a significant source of anthropogenic disturbance while also providing recreation and revenue. Ski-run creation always results in some level of disturbance, but disturbance intensity varies greatly with construction method. Ski runs may be established either by clearing (cutting and removing tall vegetation) or by clearing and then machine-grading (leveling the soil surface with heavy equipment). To quantify how these different intensities of initial disturbance affect ecosystem properties, we extensively surveyed vegetation, soils, and environmental characteristics on cleared ski runs, graded ski runs, and adjacent reference forests across seven large downhill ski resorts in the northern Sierra Nevada, USA. We found that the greater disturbance intensity associated with grading resulted in greater impacts on all ecosystem properties considered, including plant community composition and diversity, soil characteristics relating to processes of nutrient cycling and retention, and measures of erosion potential. We also found that cleared ski runs retained many ecological similarities to reference forests and might even offer some added benefits by possessing greater plant species and functional diversity than either forests or graded runs. Because grading is more damaging to multiple indicators of ecosystem function, clearing rather than grading should be used to create ski slopes wherever practical.

  12. Increased light-use efficiency in northern terrestrial ecosystems indicated by CO 2 and greening observations: INCREASE IN NH LIGHT USE EFFICIENCY

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Rebecca T. [Science and Solutions for a Changing Planet DTP, Imperial College London, London UK; AXA Chair Programme in Biosphere and Climate Impacts, Department of Life Sciences, Imperial College London, London UK; Department of Physics, Imperial College London, London UK; Prentice, Iain Colin [AXA Chair Programme in Biosphere and Climate Impacts, Department of Life Sciences, Imperial College London, London UK; Grantham Institute: Climate Change and the Environment, Imperial College London, London UK; Graven, Heather [Department of Physics, Imperial College London, London UK; Grantham Institute: Climate Change and the Environment, Imperial College London, London UK; Ciais, Philippe [Laboratoire des Sciences du Climat et de l' Environnement, Saint-Aubin France; Fisher, Joshua B. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California USA; Hayes, Daniel J. [School of Forest Resources, University of Maine, Orono Maine USA; Huang, Maoyi [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Huntzinger, Deborah N. [School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff Arizona USA; Ito, Akihiko [Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba Japan; Jain, Atul [Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana Illinois USA; Mao, Jiafu [Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Michalak, Anna M. [Department of Global Ecology, Carnegie Institution for Science, Stanford California USA; Peng, Shushi [Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing China; Poulter, Benjamin [Department of Ecology, Montana State University, Bozeman Montana USA; Ricciuto, Daniel M. [Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Shi, Xiaoying [Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Schwalm, Christopher [Woods Hole Research Center, Falmouth Massachusetts USA; Tian, Hanqin [International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn Alabama USA; Zeng, Ning [Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary Center, University of Maryland, College Park Maryland USA

    2016-11-04

    Observations show an increasing amplitude in the seasonal cycle of CO2 (ASC) north of 45°N of 56 ± 9.8% over the last 50 years and an increase in vegetation greenness of 7.5–15% in high northern latitudes since the 1980s. However, the causes of these changes remain uncertain. Historical simulations from terrestrial biosphere models in the Multiscale Synthesis and Terrestrial Model Intercomparison Project are compared to the ASC and greenness observations, using the TM3 atmospheric transport model to translate surface fluxes into CO2 concentrations. We find that the modeled change in ASC is too small but the mean greening trend is generally captured. Modeled increases in greenness are primarily driven by warming, whereas ASC changes are primarily driven by increasing CO2. We suggest that increases in ecosystem-scale light use efficiency (LUE) have contributed to the observed ASC increase but are underestimated by current models. We highlight potential mechanisms that could increase modeled LUE.

  13. Mapping of critical loads of acidity for the Italian terrestrial ecosystems; Mappa dei carichi critici di acidita' totale riferita al territorio italiano

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, P.; Brini, S.; Delmonaco, G.; Liburdi, C.; Trocciola, A.; Vetrella, G. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1999-07-01

    In this report the mapping of critical loads of acidity for the Italian terrestrial ecosystems is presented. The level 0 method (Stockholm Environment Institute) has been used to determine sensitivity to acid deposition; this semi-quantitative method has been modified to address some Italian characteristics. The sensitivity of the Italian soils to acidification is not particularly elevated: there are really only few small areas with poor tolerance to acid depositions in the north-east Italy, Alpine and Prealpine region. [Italian] Nel presente relazione vengono riportati i risultati della mappatura riferita ad ecosistemi terrestri del territorio italiano, dei carichi critici per l'acidita' totale. Il calcolo dei carichi e' stato eseguito sulla base della metodologia messa a punto dallo Stockholm Environment Institute con alcune modifiche per adattarlo meglio alle caratteristiche del territorio italiano. Si dimostra che la sensibilita' dei suoli italiani all'acidificazione non sia particolarmente elevata: sono state riscontrate infatti solo alcune aree, peraltro con superficie limitata, con una scarsa tolleranza alle deposizioni acide nelle zone del Nord Est, in zona alpina e prealpina.

  14. EcoDoses improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2003

    International Nuclear Information System (INIS)

    Bergan, T.; Liland, A.

    2004-05-01

    The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The first part, conducted in 2003, has focussed on an extensive collation and review of both published and unpublished data from all the Nordic countries for the nuclear weapons fallout period and the post-Chemobyl period. This included data on radionuclides in air filters, precipitation, soil samples, milk and reindeer. Based on this, an improved model for estimating radioactive fallout based on precipitation data during the nuclear weapons fallout period has been developed. Effective ecological half- lives for 137Cs and 90Sr in milk have been calculated for the nuclear weapons fallout period. For reindeer the ecological half- lives for 137Cs have been calculated for both the nuclear weapons fallout period and the post-Chemobyl period. The data were also used to compare modelling results with observed concentrations. This was done at a workshop where the radioecological food-and-dose module in the ARGOS decision support system was used to predict transfer of deposited radionuclides to foodstuffs and subsequent radiation doses to man. The work conducted the first year is presented in this report and gives interesting, new results relevant for terrestrial radioecology. (au)

  15. Isotopic and anatomical evidence of an herbivorous diet in the Early Tertiary giant bird Gastornis. Implications for the structure of Paleocene terrestrial ecosystems

    Science.gov (United States)

    Angst, D.; Lécuyer, C.; Amiot, R.; Buffetaut, E.; Fourel, F.; Martineau, F.; Legendre, S.; Abourachid, A.; Herrel, A.

    2014-04-01

    The mode of life of the early Tertiary giant bird Gastornis has long been a matter of controversy. Although it has often been reconstructed as an apex predator feeding on small mammals, according to other interpretations, it was in fact a large herbivore. To determine the diet of this bird, we analyze here the carbon isotope composition of the bone apatite from Gastornis and contemporaneous herbivorous mammals. Based on 13C-enrichment measured between carbonate and diet of carnivorous and herbivorous modern birds, the carbonate δ13C values of Gastornis bone remains, recovered from four Paleocene and Eocene French localities, indicate that this bird fed on plants. This is confirmed by a morphofunctional study showing that the reconstructed jaw musculature of Gastornis was similar to that of living herbivorous birds and unlike that of carnivorous forms. The herbivorous Gastornis was the largest terrestrial tetrapod in the Paleocene biota of Europe, unlike the situation in North America and Asia, where Gastornis is first recorded in the early Eocene, and the largest Paleocene animals were herbivorous mammals. The structure of the Paleocene terrestrial ecosystems of Europe may have been similar to that of some large islands, notably Madagascar, prior to the arrival of humans.

  16. Near Real-Time Disturbance Detection in Terrestrial Ecosystems Using Satellite Image Time Series: Drought Detection in Somalia

    OpenAIRE

    Jan Verbesselt; Achim Zeileis; Martin Herold

    2011-01-01

    Near real-time monitoring of ecosystem disturbances is critical for addressing impacts on carbon dynamics, biodiversity, and socio-ecological processes. Satellite remote sensing enables cost-effective and accurate monitoring at frequent time steps over large areas. Yet, generic methods to detect disturbances within newly captured satellite images are lacking. We propose a generic time series based disturbance detection approach by modelling stable historical behaviour to enable detection of a...

  17. Nitrogen, organic carbon and sulphur cycling in terrestrial ecosystems: linking nitrogen saturation to carbon limitation of soil microbial processes

    Czech Academy of Sciences Publication Activity Database

    Kopáček, Jiří; Cosby, B. J.; Evans, C. D.; Hruška, J.; Moldan, F.; Oulehle, F.; Šantrůčková, H.; Tahovská, K.; Wright, R. F.

    2013-01-01

    Roč. 115, 1-3 (2013), s. 33-51 ISSN 0168-2563. [BIOGEOMON : international symposium on ecosystem behavior /7./. Northport, 15.07.2012-20.07.2012] R&D Projects: GA ČR(CZ) GAP504/12/1218 Institutional support: RVO:60077344 Keywords : nitrogen * carbon * sulphur * acidification * forest soil * modelling Subject RIV: DJ - Water Pollution ; Quality Impact factor: 3.730, year: 2013

  18. Integrated plant nutrient management on diversified cropping system in aqua-terrestrial ecosystem for yield potentiality, quality and rural sustainability

    OpenAIRE

    PUSTE, ANANDAMOY DR.; DE, PRALAY ER.; MAITY, TAPAN KUMAR DR.

    2009-01-01

    Balanced and integrated plant nutrient management is imperative in agricultural production system including its quality - more applicable to those of developing country in the world. Like arable land in wetland ecosystem, nitrogen and other essential key plant elements and its management is also an integral part for so many beneficial aquatic crops (food, non-food etc.). With this significant importance of IPNM, number of case studies were undertaken through TOT, TDET based integrated aquacul...

  19. Coupling the Canadian Terrestrial Ecosystem Model (CTEM v. 2.0) to Environment and Climate Change Canada's greenhouse gas forecast model (v.107-glb)

    Science.gov (United States)

    Badawy, Bakr; Polavarapu, Saroja; Jones, Dylan B. A.; Deng, Feng; Neish, Michael; Melton, Joe R.; Nassar, Ray; Arora, Vivek K.

    2018-02-01

    The Canadian Land Surface Scheme and the Canadian Terrestrial Ecosystem Model (CLASS-CTEM) together form the land surface component in the family of Canadian Earth system models (CanESMs). Here, CLASS-CTEM is coupled to Environment and Climate Change Canada (ECCC)'s weather and greenhouse gas forecast model (GEM-MACH-GHG) to consistently model atmosphere-land exchange of CO2. The coupling between the land and the atmospheric transport model ensures consistency between meteorological forcing of CO2 fluxes and CO2 transport. The procedure used to spin up carbon pools for CLASS-CTEM for multi-decadal simulations needed to be significantly altered to deal with the limited availability of consistent meteorological information from a constantly changing operational environment in the GEM-MACH-GHG model. Despite the limitations in the spin-up procedure, the simulated fluxes obtained by driving the CLASS-CTEM model with meteorological forcing from GEM-MACH-GHG were comparable to those obtained from CLASS-CTEM when it is driven with standard meteorological forcing from the Climate Research Unit (CRU) combined with reanalysis fields from the National Centers for Environmental Prediction (NCEP) to form CRU-NCEP dataset. This is due to the similarity of the two meteorological datasets in terms of temperature and radiation. However, notable discrepancies in the seasonal variation and spatial patterns of precipitation estimates, especially in the tropics, were reflected in the estimated carbon fluxes, as they significantly affected the magnitude of the vegetation productivity and, to a lesser extent, the seasonal variations in carbon fluxes. Nevertheless, the simulated fluxes based on the meteorological forcing from the GEM-MACH-GHG model are consistent to some extent with other estimates from bottom-up or top-down approaches. Indeed, when simulated fluxes obtained by driving the CLASS-CTEM model with meteorological data from the GEM-MACH-GHG model are used as prior estimates

  20. Coupling the Canadian Terrestrial Ecosystem Model (CTEM v. 2.0 to Environment and Climate Change Canada's greenhouse gas forecast model (v.107-glb

    Directory of Open Access Journals (Sweden)

    B. Badawy

    2018-02-01

    Full Text Available The Canadian Land Surface Scheme and the Canadian Terrestrial Ecosystem Model (CLASS-CTEM together form the land surface component in the family of Canadian Earth system models (CanESMs. Here, CLASS-CTEM is coupled to Environment and Climate Change Canada (ECCC's weather and greenhouse gas forecast model (GEM-MACH-GHG to consistently model atmosphere–land exchange of CO2. The coupling between the land and the atmospheric transport model ensures consistency between meteorological forcing of CO2 fluxes and CO2 transport. The procedure used to spin up carbon pools for CLASS-CTEM for multi-decadal simulations needed to be significantly altered to deal with the limited availability of consistent meteorological information from a constantly changing operational environment in the GEM-MACH-GHG model. Despite the limitations in the spin-up procedure, the simulated fluxes obtained by driving the CLASS-CTEM model with meteorological forcing from GEM-MACH-GHG were comparable to those obtained from CLASS-CTEM when it is driven with standard meteorological forcing from the Climate Research Unit (CRU combined with reanalysis fields from the National Centers for Environmental Prediction (NCEP to form CRU-NCEP dataset. This is due to the similarity of the two meteorological datasets in terms of temperature and radiation. However, notable discrepancies in the seasonal variation and spatial patterns of precipitation estimates, especially in the tropics, were reflected in the estimated carbon fluxes, as they significantly affected the magnitude of the vegetation productivity and, to a lesser extent, the seasonal variations in carbon fluxes. Nevertheless, the simulated fluxes based on the meteorological forcing from the GEM-MACH-GHG model are consistent to some extent with other estimates from bottom-up or top-down approaches. Indeed, when simulated fluxes obtained by driving the CLASS-CTEM model with meteorological data from the GEM-MACH-GHG model are used as

  1. Future stratospheric ozone depletion will affect a subarctic dwarf shrub ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Johanson, Ulf

    1997-02-01

    The stratospheric ozone depletion and the concomitant increase in ultraviolet-B (UV-B, 280-320 nm) radiation is of global concern due to the effects of UV-B on living organisms. To investigate the effects of increased levels of UV-B, a field irradiation system was established at a subarctic dwarf shrub heath in Northern Sweden (68 deg N). An ozone depletion of 15% under clear sky conditions was simulated over a naturally growing ecosystem. The response of both individual components and processes was studied to reveal changes in ecosystem structure and function. Species with different life strategies (evergreen or deciduous) responded differently both in magnitude and direction. The evergreen species were more responsive to UV-B regarding shoot growth, which could be due to cumulative effects in long-lived tissues, since the retardation in relative growth increased over time of exposure. Leaves of evergreen species became thicker under enhanced UV-B, while leaves of deciduous species became thinner. Decomposition studies (laboratory and in situ) showed that indirect effects of UV-B, due to changes in leaf tissue chemistry affected microbial activity and slowed down the decomposition rate. More directly, UV-B decreased the abundance of some fungal species and hence the composition of species. However, no altered decomposition rate was found when decomposition progressed under high UV-B even if the microorganisms were fewer. This could be due to the increased direct photo degradation of litter that compensates for lower microbial activity. The decomposition rate is therefore strongly dependent on the interception of UV-B at the litter layer. This research has shown that ecosystem components and processes are affected in a number of ways and that there are indications of changes in species composition in a long-term perspective due to differences in responsiveness between the different species. 128 refs, 7 figs

  2. Ecosystem carbon storage does not vary with increasing mean annual temperature in Hawaiian tropical montane wet forests

    Science.gov (United States)

    Paul Selmants; Creighton Litton; Christian P. Giardina; Greg P. Asner

    2014-01-01

    Theory and experiment agree that climate warming will increase carbon fluxes between terrestrial ecosystems and the atmosphere. The effect of this increased exchange on terrestrial carbon storage is less predictable, with important implications for potential feedbacks to the climate system. We quantified how increased mean annual temperature (MAT) affects ecosystem...

  3. Using the Terrestrial Observation and Prediction System (TOPS) to Analyze Impacts of Climate Change on Ecosystems within Northern California Climate Regions

    Science.gov (United States)

    Pitts, K.; Little, M.; Loewenstein, M.; Iraci, L. T.; Milesi, C.; Schmidt, C.; Skiles, J. W.

    2011-12-01

    The projected impacts of climate change on Northern California ecosystems using model outputs from the Terrestrial Observation and Prediction System (TOPS) for the period 1950-2099 based on 1km downscaled climate data from the Geophysical Fluid Dynamics Laboratory (GFDL) model are analyzed in this study. The impacts are analyzed for the Special Report Emissions Scenarios (SRES) A1B and A2, both maintaining present levels of urbanization constant and under projected urban expansion. The analysis is in support of the Climate Adaptation Science Investigation at NASA Ames Research Center. A statistical analysis is completed for time series of temperature, precipitation, gross primary productivity (GPP), evapotranspiration, soil runoff, and vapor pressure deficit. Trends produced from this analysis show that increases in maximum and minimum temperatures lead to declines in peak GPP, length of growing seasons, and overall declines in runoff within the watershed. For Northern California, GPP is projected under the A2 scenario to decrease by 18-25% by the 2090 decade as compared to the 2000 decade. These trends indicate a higher risk to crop production and other ecosystem services, as conditions would be less hospitable to vegetation growth. The increase in dried out vegetation would then lead to a higher risk of wildfire and mudslides in the mountainous regions.

  4. Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting

    International Nuclear Information System (INIS)

    Sneddon, Jennifer; Clemente, Rafael; Riby, Philip; Lepp, Nicholas W.

    2009-01-01

    Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents - washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota. - Source-receptor pathway analysis of a managed game shooting site showed no environmental risk of trace element transfer.

  5. Dynamics of Water Yield From China's Terrestrial Ecosystems in the 20th Century: Impact of Climate Change, Atmospheric Carbon Dioxide, Tropospheric Ozone, and Land- Use

    Science.gov (United States)

    Liu, M.; Tian, H.; Zhang, C.; Ren, W.; Liu, J.

    2006-05-01

    The availability of freshwater resources is critical to China's economic development and human's health. Water yield, the runoff from the drainage basin, is one important index of ecosystem service that directly controls the total freshwater availability and rain erosity. The monsoon climate system and the complexity of natural geography in China lead to substantially spatial and temporal variability in water resources. It has been argued that intensively human activity and air pollution have altered the terrestrial water cycle in the last century. However, little is known about the magnitude and historical trend of water yield across China as well as underlying mechanisms. This study used a process-based Dynamic Land Ecosystem Model (DLEM) to address the effects of multiple stressors on water yield nationwide during 1900 to 2000. These multiple stressors include changes in climate, atmospheric CO2 concentration, tropospheric ozone, and land-use (including cropland expansion, cropland abandonment, urbanization, and irrigation). By using optimal fingerprinting statistical techniques and factorial simulation experiments, we determined the relative contribution of these multiple stressors to water yield for the study period. The simulated results were evaluated against river's runoff records and watershed observations. Our simulated results suggest that the land-use change and precipitation appear to be two primary factors controlling water yield in China.

  6. Affecting Factors and Recent Improvements of the Photochemical Reflectance Index (PRI for Remotely Sensing Foliar, Canopy and Ecosystemic Radiation-Use Efficiencies

    Directory of Open Access Journals (Sweden)

    Chao Zhang

    2016-08-01

    Full Text Available Accurately assessing terrestrial gross primary productivity (GPP is crucial for characterizing the climate-carbon cycle. Remotely sensing the photochemical reflectance index (PRI across vegetation functional types and spatiotemporal scales has received increasing attention for monitoring photosynthetic performance and simulating GPP over the last two decades. The factors confounding PRI variation, especially on long timescales, however, require the improvement of PRI understanding to generalize its use for estimating carbon uptake. In this review, we summarize the most recent publications that have reported the factors affecting PRI variation across diurnal and seasonal scales at foliar, canopy and ecosystemic levels; synthesize the reported correlations between PRI and ecophysiological variables, particularly with radiation-use efficiency (RUE and net carbon uptake; and analyze the improvements in PRI implementation. Long-term variation of PRI could be attributed to changes in the size of constitutive pigment pools instead of xanthophyll de-epoxidation, which controls the facultative short-term changes in PRI. Structural changes at canopy and ecosystemic levels can also affect PRI variation. Our review of the scientific literature on PRI suggests that PRI is a good proxy of photosynthetic efficiency at different spatial and temporal scales. Correcting PRI by decreasing the influence of physical or physiological factors on PRI greatly strengthens the relationships between PRI and RUE and GPP. Combining PRI with solar-induced fluorescence (SIF and optical indices for green biomass offers additional prospects.

  7. The relative roles of climate and land use in the degradation of a terrestrial ecosystem: a case study from Kjarardalur, West Iceland

    Science.gov (United States)

    Erlendsson, Egill; Gísladóttir, Guðrún

    2016-04-01

    Around AD 870 the virgin environment of Iceland became populated by humans and mammal land herbivores. Since then, the island has lost nearly all of its native birch woodland, resulting in dramatic degradation of landscapes and ecosystems, attributed mainly to over-exploitation of woodlands and late-medieval climate deterioration. As part of policy making in agriculture, a heated debate is ongoing over limitations to sheep grazing in pastures suffering from long-term degradation. In this context the history of climate and land use is of great importance. Those who consider grazing a minimal attribute to land degradation argue that the harsh climate conditions of the little ice age are the primary mechanism behind the current degraded landscape. Others err on the side of caution and propose a careful approach to grazing. This study forms a contribution to the historical context of the impact of grazing upon the Icelandic terrestrial ecosystem. Using the analyses of pollen and spores from coprophilous fungi as principal methods, we present data about historical environmental change from within two different land holdings in Kjarardalur Valley, West Iceland. One dataset comes from within a landholding governed by the chieftain farm Reykholt, the other comes from within the land of the indipendent farm, Norðtunga. In the past the valley was used primarily as a pasture, associated with shielings (organised seasonal grazing). Pollen data from the pasture in Kjarardalur Valley, West Iceland, demonstrate a rapid loss of birch (Betula pubescens) woodland from grazing areas owned by the major farm and institution, Reykholt. The suppressive nature of grazing is demonstrated by the expansion of woodland as soon when animal stocks are reduced, probably as a consequence of the bubonic plague after AD 1402. Resumed exploitation of resources eventually depleted all birch woodland from the Reykholt landholding and precipitated soil erosion. The trajectory of environmental change

  8. Description, calibration and sensitivity analysis of the local ecosystem submodel of a global model of carbon and nitrogen cycling and the water balance in the terrestrial biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kercher, J.R. [Lawrence Livermore National Lab., CA (United States); Chambers, J.Q. [Lawrence Livermore National Lab., CA (United States)]|[California Univ., Santa Barbara, CA (United States). Dept. of Biological Sciences

    1995-10-01

    We have developed a geographically-distributed ecosystem model for the carbon, nitrogen, and water dynamics of the terrestrial biosphere TERRA. The local ecosystem model of TERRA consists of coupled, modified versions of TEM and DAYTRANS. The ecosystem model in each grid cell calculates water fluxes of evaporation, transpiration, and runoff; carbon fluxes of gross primary productivity, litterfall, and plant and soil respiration; and nitrogen fluxes of vegetation uptake, litterfall, mineralization, immobilization, and system loss. The state variables are soil water content; carbon in live vegetation; carbon in soil; nitrogen in live vegetation; organic nitrogen in soil and fitter; available inorganic nitrogen aggregating nitrites, nitrates, and ammonia; and a variable for allocation. Carbon and nitrogen dynamics are calibrated to specific sites in 17 vegetation types. Eight parameters are determined during calibration for each of the 17 vegetation types. At calibration, the annual average values of carbon in vegetation C, show site differences that derive from the vegetation-type specific parameters and intersite variation in climate and soils. From calibration, we recover the average C{sub v} of forests, woodlands, savannas, grasslands, shrublands, and tundra that were used to develop the model initially. The timing of the phases of the annual variation is driven by temperature and light in the high latitude and moist temperate zones. The dry temperate zones are driven by temperature, precipitation, and light. In the tropics, precipitation is the key variable in annual variation. The seasonal responses are even more clearly demonstrated in net primary production and show the same controlling factors.

  9. Final Report on "Rising CO2 and Long-term Carbon Storage in Terrestrial Ecosystems: An Empirical Carbon Budget Validation"

    Energy Technology Data Exchange (ETDEWEB)

    J. Patrick Megonigal; Bert G. Drake

    2010-08-27

    The primary goal of this report is to report the results of Grant DE-FG02-97ER62458, which began in 1997 as Grant DOE-98-59-MP-4 funded through the TECO program. However, this project has a longer history because DOE also funded this study from its inception in 1985 through 1997. The original grant was focused on plant responses to elevated CO2 in an intact ecosystem, while the latter grant was focused on belowground responses. Here we summarize the major findings across the 25 years this study has operated, and note that the experiment will continue to run through 2020 with NSF support. The major conclusions of the study to date are: (1 Elevated CO2 stimulated plant productivity in the C3 plant community by ~30% during the 25 year study. The magnitude of the increase in productivity varied interannually and was sometime absent altogether. There is some evidence of down-regulation at the ecosystem level across the 25 year record that may be due to interactions with other factors such as sea-level rise or long-term changes in N supply; (2) Elevated CO2 stimulated C4 productivity by <10%, perhaps due to more efficient water use, but C3 plants at elevated CO2 did not displace C4 plants as predicted; (3) Increased primary production caused a general stimulation of microbial processes, but there were both increases and decreases in activity depending on the specific organisms considered. An increase in methanogenesis and methane emissions implies elevated CO2 may amplify radiative forcing in the case of wetland ecosystems; (4) Elevated CO2 stimulated soil carbon sequestration in the form of an increase in elevation. The increase in elevation is 50-100% of the increase in net ecosystem production caused by elevated CO2 (still under analysis). The increase in soil elevation suggests the elevated CO2 may have a positive outcome for the ability of coastal wetlands to persist despite accelerated sea level rise; (5) Crossing elevated CO2 with elevated N causes the elevated CO

  10. Impacts of fire on nitrogen cycling in aquatic and terrestrial ecosystems in the Yukon-Kuskokwim River Delta, AK

    Science.gov (United States)

    Schade, J. D.; Jardine, L. E.; Bristol, E. M.; Navarro-Perez, E.; Melton, S.; Jimmie, J. A.; Natali, S.; Mann, P. J.; Holmes, R. M.

    2017-12-01

    Global climate change is having a disproportionate impact on northern high latitudes, including rapid increases in temperature, changes in precipitation, and increasing fire frequency and severity. Wildfires have been shown to strongly influence ecosystem processes through acceleration of permafrost thaw and increased nitrogen (N) availability, the effects of which may increase gaseous loss of carbon (C) to the atmosphere, increase primary production by alleviating N limitation, or both. The extent of these fire impacts has not been well-documented in the Arctic, particularly in areas of discontinuous permafrost. In 2015, the Yukon-Kuskokwim River Delta (YK Delta) in southwestern Alaska experienced the largest fire season in recorded history, providing an opportunity to study wildfire impacts on an area particularly vulnerable to permafrost thaw. Our objectives were to study the impacts of these fires on nitrogen availability in a range of land cover classes, including peat plateaus, channel fens, and aquatic ecosystems distributed across the landscapes. We sampled soils from several vegetation patches on burned and unburned peat plateaus, and soil and surface waters from fens, small ponds, and streams downslope of these sites. All water samples were filtered through GFF filters in the field. Soils were transported frozen to the Woods Hole Research Center and extracted in KCl. All water samples and extracts were analyzed for NH4 and NO3 concentrations. We found substantially higher concentrations of extractable NH4 in burned soils, but very little extractable NO3 in either burned or unburned soils. Water samples also showed higher NH4 in aquatic ecosystems in burned watersheds, but, in contrast to soils, showed relatively high NO3 concentrations, particularly in waters from lower landscape positions. Overall, aquatic ecosystems exhibited higher NO3: NH4 ratios than soil extractions, and increasing NO3: NH4 downslope. These results suggest significant export of

  11. Field calibration of soil-core microcosms for evaluating fate and effects of genetically engineered microorganisms in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, H Jr; Fredrickson, J K; Bentjen, S A; Workman, D J; Li, S W; Thomas, J M

    1991-04-01

    Pacific Northwest Laboratory compared intact soil-core microcosms and the field for ecosystem structural and functional properties after the introduction of a model genetically engineered microorganism (GEM). This project used two distinct microbial types as model GEMs, Gram-negative Pseudomonas sp. RC1, which was an aggressive root colonizer, and Gram-positive Streptomyces lividans TK24. The model GEMs were added to surface soil in separate studies, with RC1 studied throughout the growth of winter wheat (Triticum aestivum), while TK24 was studied throughout a ten month period. Also, RC1 was used in studies conducted during two consecutive field seasons (1988 to 1990) to determine how year-to-year field variability influenced the calibration of microcosms with the field. The main conclusions of this research were that intact soil-core microcosms can be useful to simulate the field for studies of microbial fate and effects on ecosystem structural and functional properties. In general, microcosms in the growth chamber, which simulated average field variations, were similar to the field for most parameters or differences could be attributed to the great extremes in temperature that occurred in the field compared to the microcosms. Better controls of environmental variables including temperature and moisture will be necessary to more closely simulate the field for future use of microcosms for risk assessment. 126 refs., 13 figs., 12 tabs.

  12. Terrestrial radioecology

    International Nuclear Information System (INIS)

    Ohmomo, Yoichiro

    1992-01-01

    Environmental radioecology is a science of studying radionuclide transfer and distribution in the environmental ecosystem and the effects of radiation of the ecosystem. This review highlights radionuclide transfer to crops. There is, however, limited data available on this field in Japan. Therefore, a history of environmental radioecological study in Japan is briefly mentioned: radioecological study has been reflected by social backgrounds, including nuclear explosion and peaceful application of radionuclides. In view of the relationship between siting of nuclear installations and dietary habits for Japanese, research on hydrological radioecology has actually preceded that of terrestrial radioecology. Transfer parameters are discussed in terms of deposition velosity, interception fraction, environmental halftimes, and transfer coefficients from soils to crops. (N.K.) 50 refs

  13. Evaluation of dimensionality reduction techniques in hyperspectral imagery and their application for the classification of terrestrial ecosystems

    Science.gov (United States)

    Ibarrola-Ulzurrun, Edurne; Marcello-Ruiz, Javier; Gonzalo-Martín, Consuelo

    2017-10-01

    The hyperspectral imagery is formed by a several narrow and continuous bands covering different regions of the electromagnetic spectrum, such as spectral bands of the visible, near infrared and far infrared. Hyperspectral imagery provides extremely higher spectral resolution than high spatial resolution multispectral imagery, improving the detection capability of terrestrial objects. The greatest difficulty found in the hyperspectral processing is the high dimensionality of these data, which brings out the 'Hughes' phenomenon. This phenomenon specifies that the size of training set required for a given classification increases exponentially with the number of spectral bands. Therefore, the dimensionality of the hyperspectral data is an important drawback when applying traditional classification or pattern recognition approaches to this hyperspectral imagery. In our context, the dimensionality reduction is necessary to obtain accurate thematic maps of natural protected areas. Dimensionality reduction can be divided into the feature-selection algorithms and featureextraction algorithms. We focus the study in the feature-extraction algorithms like Principal Component Analysis (PCA), Minimum Noise Fraction (MNF) and Independent Component Analysis (ICA). After a review of the state-of-art, it has been observed a lack of a comparative study on the techniques used in the hyperspectral imagery dimensionality reduction. In this context, our objective was to perform a comparative study of the traditional techniques of dimensionality reduction (PCA, MNF and ICA) to evaluate their performance in the classification of high spatial resolution imagery of the CASI (Compact Airborne Spectrographic Imager) sensor.

  14. Characteristic of pollution with groundwater inflow (90)Sr natural waters and terrestrial ecosystems near a radioactive waste storage.

    Science.gov (United States)

    Lavrentyeva, G V

    2014-09-01

    The studies were conducted in the territory contaminated by (90)Sr with groundwater inflow as a result of leakage from the near-surface trench-type radioactive waste storage. The vertical soil (90)Sr distribution up to the depth of 2-3 m is analyzed. The area of radioactive contamination to be calculated with a value which exceeds the minimum significant activity 1 kBq/kg for the tested soil layers: the contaminated area for the 0-5 cm soil layer amounted to 1800 ± 85 m(2), for the 5-10 cm soil layer amounted to 300 ± 12 m(2), for the 10-15 cm soil layer amounted to 180 ± 10 m(2). It is found that (90)Sr accumulation proceeds in a natural sorption geochemical barrier of the marshy terrace near flood plain. The exposure doses for terrestrial mollusks Bradybaena fruticum are presented. The excess (90)Sr interference level was registered both in the ground and surface water during winter and summer low-water periods and autumn heavy rains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Composition, dynamics, and fate of leached dissolved organic matter in terrestrial ecosystems: Results from a decomposition experiment

    Science.gov (United States)

    Cleveland, C.C.; Neff, J.C.; Townsend, A.R.; Hood, E.

    2004-01-01

    Fluxes of dissolved organic matter (DOM) are an important vector for the movement of carbon (C) and nutrients both within and between ecosystems. However, although DOM fluxes from throughfall and through litterfall can be large, little is known about the fate of DOM leached from plant canopies, or from the litter layer into the soil horizon. In this study, our objectives were to determine the importance of plant-litter leachate as a vehicle for DOM movement, and to track DOM decomposition [including dissolve organic carbon (DOC) and dissolved organic nitrogen (DON) fractions], as well as DOM chemical and isotopic dynamics, during a long-term laboratory incubation experiment using fresh leaves and litter from several ecosystem types. The water-extractable fraction of organic C was high for all five plant species, as was the biodegradable fraction; in most cases, more than 70% of the initial DOM was decomposed in the first 10 days of the experiment. The chemical composition of the DOM changed as decomposition proceeded, with humic (hydrophobic) fractions becoming relatively more abundant than nonhumic (hydrophilic) fractions over time. However, in spite of proportional changes in humic and nonhumic fractions over time, our data suggest that both fractions are readily decomposed in the absence of physicochemical reactions with soil surfaces. Our data also showed no changes in the ??13C signature of DOM during decomposition, suggesting that isotopic fractionation during DOM uptake is not a significant process. These results suggest that soil microorganisms preferentially decompose more labile organic molecules in the DOM pool, which also tend to be isotopically heavier than more recalcitrant DOM fractions. We believe that the interaction between DOM decomposition dynamics and soil sorption processes contribute to the ??13C enrichment of soil organic matter commonly observed with depth in soil profiles.

  16. Degradation of mangroves adversely affected ecosystem and rural inhabitant in the Sindh's coastal area

    International Nuclear Information System (INIS)

    Naqvi, S.R.; Inam, Z.

    2005-01-01

    Mangroves the ecological treasure of Sindh, are facing a steady decline due to in active Government policies and lack of interest of local people. Mangroves provide important breeding Zone of to the marine biodiversity because of the reduction of silt flows, the area of active growth of delta, has been reduced from an original estimate of 2600 sq km to about 260 sq km. Similarly, the area of Mangroves from 345,000 hectares, the area is now only 205000 hectares. Pakistani Mangroves rank 6th among the mangroves spread in 92 countries. Mangroves forests act as inter face b/w land and sea. It provides nutrients to marine fisheries and is vital healthy Ecosystem. During past 50 years, nearly 100,000 hectares have been destroyed. The destruction is quite high from 1975 to 1992. It is due to water shortage in the river Indus. Degradation of mangroves adversely affected ecosystem and rural inhabitant in the coastal area. Thus to find root causes of degradation and its effects this study was made. (author)

  17. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-01-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services. PMID:25005713

  18. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-07-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services.

  19. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    Science.gov (United States)

    Wittlingerová, Zdena; Macháčková, Jiřina; Petruželková, Anna; Zimová, Magdalena

    2016-03-01

    Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

  20. Climate and land use change impacts on global terrestrial ecosystems and river flows in the HadGEM2-ES Earth system model using the representative concentration pathways

    Science.gov (United States)

    Betts, R. A.; Golding, N.; Gonzalez, P.; Gornall, J.; Kahana, R.; Kay, G.; Mitchell, L.; Wiltshire, A.

    2015-03-01

    A new generation of an Earth system model now includes a number of land-surface processes directly relevant to analyzing potential impacts of climate change. This model, HadGEM2-ES, allows us to assess the impacts of climate change, multiple interactions, and feedbacks as the model is run. This paper discusses the results of century-scale HadGEM2-ES simulations from an impacts perspective - specifically, terrestrial ecosystems and water resources - for four different scenarios following the representative concentration pathways (RCPs), used in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC, 2013, 2014). Over the 21st century, simulated changes in global and continental-scale terrestrial ecosystems due to climate change appear to be very similar in all 4 RCPs, even though the level of global warming by the end of the 21st century ranges from 2 °C in the lowest scenario to 5.5° in the highest. A warming climate generally favours broadleaf trees over needleleaf, needleleaf trees over shrubs, and shrubs over herbaceous vegetation, resulting in a poleward shift of temperate and boreal forests and woody tundra in all scenarios. Although climate related changes are slightly larger in scenarios of greater warming, the largest differences between scenarios arise at regional scales as a consequence of different patterns of anthropogenic land cover change. In the model, the scenario with the lowest global warming results in the most extensive decline in tropical forest cover due to a large expansion of agriculture. Under all four RCPs, fire potential could increase across extensive land areas, particularly tropical and sub-tropical latitudes. River outflows are simulated to increase with higher levels of CO2 and global warming in all projections, with outflow increasing with mean temperature at the end of the 21st century at the global scale and in North America, Asia, and Africa. In South America, Europe, and Australia, the relationship

  1. Introduction - The impacts of the 2008 eruption of Kasatochi Volcano on terrestrial and marine ecosystems in the Aleutian Islands, Alaska

    Science.gov (United States)

    DeGange, Anthony R.; Byrd, G. Vernon; Walker, Lawrence R.; Waythomas, C.F.

    2010-01-01

    The Aleutian Islands are situated on the northern edge of the so-called “Pacific Ring of Fire,” a 40,000-km-long horseshoe-shaped assemblage of continental landmasses and islands bordering the Pacific Ocean basin that contains many of the world's active and dormant volcanoes. Schaefer et al. (2009) listed 27 historically active volcanoes in the Aleutian Islands, of which nine have had at least one major eruptive event since 1990. Volcanic eruptions are often significant natural disturbances, and ecosystem responses to volcanic eruptions may vary markedly with eruption style (effusive versus explosive), frequency, and magnitude of the eruption as well as isolation of the disturbed sites from potential colonizing organisms (del Moral and Grishin, 1999). Despite the relatively high frequency of volcanic activity in the Aleutians, the response of island ecosystems to volcanic disturbances is largely unstudied because of the region's isolation. The only ecological studies in the region that address the effects of volcanic activity were done on Bogoslof Island, a remote, highly active volcanic island in the eastern Aleutians, which grew from a submarine eruption in 1796 (Merriam, 1910; Byrd et al., 1980; Byrd and Williams, 1994). Nevertheless, in the 214 years of Bogoslof's existence, the island has been visited only intermittently.Kasatochi Island is a small (2.9 km by 2.6 km, 314 m high) volcano in the central Aleutian Islands of Alaska (52.17°N latitude, 175.51°W longitude; Fig. 1) that erupted violently on 7-8 August 2008 after a brief, but intense period of precursory seismic activity (Scott et al., 2010 [this issue]; Waythomas et al., in review). The island is part of the Aleutian arc volcanic front, and is an isolated singular island. Although the immediate offshore areas are relatively shallow (20–50 m water depth), the island is about 10 km south of the 2000 m isobath, north of which, ocean depths increase markedly. Kasatochi is located between the

  2. Impact of 1998-2002 Midlatitude Drought and Warming on Terrestrial Ecosystem and the Global Carbon Cycle

    Science.gov (United States)

    Zeng, N.; Qian, H.; Roedenbeck, C.; Heimannn, M.

    2006-05-01

    A rare drought occured from 1998 to 2002 across much of the North Hemisphere midlatitude regions. Using observation data and numerical models, we analyze the impact of this event on terrestrail ecosystems and the global carbon cycle. The biological productivity in these regions were found to decrease by 0.9 PgC yr-1 or 5% compared to the average of th eprevious two decades, in conjunction with significantly reduced vegetation greenness. The drought led to a land carbon release that is large enough to significantly modify the canonical tropically dominated ENSO response. An atmospheric inversion reveals that during the 1998-2002 drought period, Northern Hemisphere midlatitude changes from a 19980-1998 average of 0.7 PgC yr-1 carbon sink to nearly neutral to the atmosphere , while a forward model suggests a changes of 1.3 PgC yr-1 in the same direction . This large CO2 source explains the consecuvie larege increase in atmposphere CO2 growth rate of about 2 ppmv yr-1 in recent years. This Northern Hemisphere CO2 anomaly was largely caused by reduced vegetation growth due to leass precipitation, but also with significant contribution from the driect effect of more respiration loass and the indirectly effect of more severe drought due to higher temperature. Since the Northern Hemisphere midlatitude landscape has been significantly modified by agriculture, grazing, irrigation and fire suppression, the strong signature in the global carbon cycle of a drought mostly initiated by changes in tropical oceanic temperature is a remarkable manifestation of lcimate variability, with significant implication for carbon cycle response and feedback to future cliamte change.

  3. Effects of modified UV-B radiation on terrestrial ecosystems; Auswirkungen veraenderter UV-B-Strahlung auf terrestrische Oekosysteme

    Energy Technology Data Exchange (ETDEWEB)

    Tevini, M. [Karlsruhe Univ. (T.H.) (Germany). Botanisches Inst. 2

    1994-10-01

    The author describes the effects of anthropogenically modified UV-B radiation on plants and aquatic ecosystems. The modified radiation may cause reduced growth of leaves and shoots, partial reduction of the photosynthesis activity, and reduced biomass production (i.e. a loss of yield). Although the UV damage may be compensated to a certain degree by a synthesis of protective pigments (cinnamonic acids and flavonoids) or by UV repair mechanisms via the enyzme photolyase, the upper limit of this adapability seems to have already been reached. One frequently observed effect of the increase in UV radiation in aquatic systems is the loss of phytoplancton biomass by 6 - 10%.Since phytoplancton is the basis of the marine food chain, this may have long-term effects on the number and distribution of species and on fish protein for the human diet. Further, the loss of biomass causes a reduction of carbon dioxide fixation, which may have consequences for the global carbon cycle. (orig.) [Deutsch] Der Autor beschreibt die Auswirkungen anthropogen veraenderter UV-B-Strahlung auf Pflanzen und aquatische Oekosysteme. Durch die veraenderte Strahlung kann es zu vermindertem Blatt- und Sprosswachstum, zur partiellen Reduktion der Photosyntheseaktivitaet und zu verringerter Biomasseproduktion, d.h. zu einem Ertragsverlust kommen. Die UV-Schaedigung kann zwar durch die Synthese von Schutzpigmenten (Zimtsaeuren und Flavonoide) oder durch UV-Reparaturmechanismen ueber das Enzym Photolyase in gewissem Masse kompensiert werden, die obere Grenze dieser Adaptationsfaehigkeit scheint aber bereits erreicht zu sein. Ein beobachteter Effekt des UV-Strahlungsanstiegs in aquatischen Systemen ist der Verlust der Phytoplankton-Biomasse um 6% - 10%. Da das Phytoplankton die Grundlage der marinen Nahrungskette bildet, sind Rueckwirkungen auf die Artenzusammensetzung und die menschliche Ernaehrung mit Fischprotein moeglich. Weiterhin fuehrt der Verlust an Biomasse zu einer Reduzierung der

  4. Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview

    International Nuclear Information System (INIS)

    Rozema, Jelte; Boelen, Peter; Blokker, Peter

    2005-01-01

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. - Polar plant responses to UV-B may be different in the Arctic than Antarctic regions

  5. EcoDoses. Improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2004

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Sven P.; Isaksson, M.; Nilsson, Elisabeth (and others)

    2005-07-01

    The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The present report sums up the work performed in the second phase of the project. The main topics in 2004 have been: (i) A continuation of previous work with a better approach for estimating global fallout on a regional or national scale, based on a correlation between precipitation and deposition rates. (ii) Fur-ther extension of the EcoDoses milk database. Estimation of effective ecological half lives of {sup 137}Cs in cows milk focussing on suitable post-Chernobyl time-series. Modelling integrated transfer of {sup 13}7{sup C}s to cow's milk from Nordic countries. (iii) Determination of effective ecological half lives for fresh water fish from Nordic lakes. (iv) Investigate ra-dioecological sensitivity for Nordic populations. (v) Food-chain modelling using the Eco-sys-model, which is the underlying food- and dose-module in several computerised deci-sion-making systems. (au)

  6. Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview

    Energy Technology Data Exchange (ETDEWEB)

    Rozema, Jelte [Department of Systems Ecology, Institute of Ecological Science, Climate Centre, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands)]. E-mail: jelte.rozema@ecology.falw.vu.nl; Boelen, Peter [Department of Systems Ecology, Institute of Ecological Science, Climate Centre, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Blokker, Peter [Department of Systems Ecology, Institute of Ecological Science, Climate Centre, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands)

    2005-10-15

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. - Polar plant responses to UV-B may be different in the Arctic than Antarctic regions.

  7. Assessing the Impacts of forest degradation on water, energy, and carbon budgets in Amazon forest using the Functionally Assembled Terrestrial Ecosystem Simulator

    Science.gov (United States)

    Huang, M.; Xu, Y.; Longo, M.; Keller, M.; Knox, R. G.; Koven, C.; Fisher, R.

    2017-12-01

    Tropical forest degradation from logging, fire, and fragmentation not only alters carbon stocks and carbon fluxes, but also impacts physical land-surface properties such as albedo and roughness length. Such impacts are poorly quantified to date due to difficulties in accessing and maintaining observational infrastructures, and the lack of proper modeling tools for capturing the interactions among biophysical properties, ecosystem demography, and biogeochemical cycling in tropical forests. As a first step to address these limitations, we implemented a selective logging module into the Functional Assembled Terrestrial Ecosystem Simulator (FATES) and parameterized the model to reproduce the selective logging experiment at the Tapajos National Forest in Brazil. The model was spun up until it reached the steady state, and simulations with and without logging were compared with the eddy covariance flux towers located at the logged and intact sites. The sensitivity of simulated water, energy, and carbon fluxes to key plant functional traits (e.g. Vcmax and leaf longevity) were quantified by perturbing their values within their documented ranges. Our results suggest that the model can reproduce water and carbon fluxes in intact forests, although sensible heat fluxes were overestimated. The effects of logging intensity and techniques on fluxes were assessed by specifying different disturbance parameters in the models (e.g., size-dependent mortality rates associated with timber harvest, collateral damage, and mechanical damage for infrastructure construction). The model projections suggest that even though the degraded forests rapidly recover water and energy fluxes compared with old-growth forests, the recovery times for carbon stocks, forest structure and composition are much longer. In addition, the simulated recovery trajectories are highly dependent on choices of values for functional traits. Our study highlights the advantages of an Earth system modeling approach

  8. How stock of origin affects performance of individuals across a meta-ecosystem: an example from sockeye salmon.

    Science.gov (United States)

    Griffiths, Jennifer R; Schindler, Daniel E; Seeb, Lisa W

    2013-01-01

    Connectivity among diverse habitats can buffer populations from adverse environmental conditions, influence the functioning of meta-ecosystems, and ultimately affect the reliability of ecosystem services. This stabilizing effect on populations is proposed to derive from complementarity in growth and survival conditions experienced by individuals in the different habitats that comprise meta-ecosystems. Here we use the fine scale differentiation of salmon populations between diverse lake habitats to assess how rearing habitat and stock of origin affect the body condition of juvenile sockeye salmon. We use genetic markers (single nucleotide polymorphisms) to assign individuals of unknown origin to stock group and in turn characterize ecologically relevant attributes across habitats and stocks. Our analyses show that the body condition of juvenile salmon is related to the productivity of alternative habitats across the watershed, irrespective of their stock of origin. Emigrants and residents with genetic origins in the high productivity lake were also differentiated by their body condition, poor and high respectively. These emigrants represented a substantial proportion of juvenile sockeye salmon rearing in the lower productivity lake habitat. Despite emigrants originating from the more productive lake, they did not differ in body condition from the individuals spawned in the lower productivity, recipient habitat. Genetic tools allowed us to assess the performance of different stocks groups across the diverse habitats comprising their meta-ecosystem. The ability to characterize the ecological consequences of meta-ecosystem connectivity can help develop strategies to protect and restore ecosystems and the services they provide to humans.

  9. A trait-based framework for predicting when and where microbial adaptation to climate change will affect ecosystem functioning

    Science.gov (United States)

    Wallenstein, Matthew D.; Hall, Edward K.

    2012-01-01

    As the earth system changes in response to human activities, a critical objective is to predict how biogeochemical process rates (e.g. nitrification, decomposition) and ecosystem function (e.g. net ecosystem productivity) will change under future conditions. A particular challenge is that the microbial communities that drive many of these processes are capable of adapting to environmental change in ways that alter ecosystem functioning. Despite evidence that microbes can adapt to temperature, precipitation regimes, and redox fluctuations, microbial communities are typically not optimally adapted to their local environment. For example, temperature optima for growth and enzyme activity are often greater than in situ temperatures in their environment. Here we discuss fundamental constraints on microbial adaptation and suggest specific environments where microbial adaptation to climate change (or lack thereof) is most likely to alter ecosystem functioning. Our framework is based on two principal assumptions. First, there are fundamental ecological trade-offs in microbial community traits that occur across environmental gradients (in time and space). These trade-offs result in shifting of microbial function (e.g. ability to take up resources at low temperature) in response to adaptation of another trait (e.g. limiting maintenance respiration at high temperature). Second, the mechanism and level of microbial community adaptation to changing environmental parameters is a function of the potential rate of change in community composition relative to the rate of environmental change. Together, this framework provides a basis for developing testable predictions about how the rate and degree of microbial adaptation to climate change will alter biogeochemical processes in aquatic and terrestrial ecosystems across the planet.

  10. Quantifying causal mechanisms to determine how protected areas affect poverty through changes in ecosystem services and infrastructure

    Science.gov (United States)

    Ferraro, Paul J.; Hanauer, Merlin M.

    2014-01-01

    To develop effective environmental policies, we must understand the mechanisms through which the policies affect social and environmental outcomes. Unfortunately, empirical evidence about these mechanisms is limited, and little guidance for quantifying them exists. We develop an approach to quantifying the mechanisms through which protected areas affect poverty. We focus on three mechanisms: changes in tourism and recreational services; changes in infrastructure in the form of road networks, health clinics, and schools; and changes in regulating and provisioning ecosystem services and foregone production activities that arise from land-use restrictions. The contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program have not yet been empirically estimated. Nearly two-thirds of the poverty reduction associated with the establishment of Costa Rican protected areas is causally attributable to opportunities afforded by tourism. Although protected areas reduced deforestation and increased regrowth, these land cover changes neither reduced nor exacerbated poverty, on average. Protected areas did not, on average, affect our measures of infrastructure and thus did not contribute to poverty reduction through this mechanism. We attribute the remaining poverty reduction to unobserved dimensions of our mechanisms or to other mechanisms. Our study empirically estimates previously unidentified contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program. We demonstrate that, with existing data and appropriate empirical methods, conservation scientists and policymakers can begin to elucidate the mechanisms through which ecosystem conservation programs affect human welfare. PMID:24567397

  11. Quantifying causal mechanisms to determine how protected areas affect poverty through changes in ecosystem services and infrastructure.

    Science.gov (United States)

    Ferraro, Paul J; Hanauer, Merlin M

    2014-03-18

    To develop effective environmental policies, we must understand the mechanisms through which the policies affect social and environmental outcomes. Unfortunately, empirical evidence about these mechanisms is limited, and little guidance for quantifying them exists. We develop an approach to quantifying the mechanisms through which protected areas affect poverty. We focus on three mechanisms: changes in tourism and recreational services; changes in infrastructure in the form of road networks, health clinics, and schools; and changes in regulating and provisioning ecosystem services and foregone production activities that arise from land-use restrictions. The contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program have not yet been empirically estimated. Nearly two-thirds of the poverty reduction associated with the establishment of Costa Rican protected areas is causally attributable to opportunities afforded by tourism. Although protected areas reduced deforestation and increased regrowth, these land cover changes neither reduced nor exacerbated poverty, on average. Protected areas did not, on average, affect our measures of infrastructure and thus did not contribute to poverty reduction through this mechanism. We attribute the remaining poverty reduction to unobserved dimensions of our mechanisms or to other mechanisms. Our study empirically estimates previously unidentified contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program. We demonstrate that, with existing data and appropriate empirical methods, conservation scientists and policymakers can begin to elucidate the mechanisms through which ecosystem conservation programs affect human welfare.

  12. Assessing Impacts of Selective Logging on Water, Energy, and Carbon Fluxes in Amazon Forests Using the Functionally Assembled Terrestrial Ecosystem Simulator (FATES)

    Science.gov (United States)

    Xu, Y.; Huang, M.; Keller, M. M.; Longo, M.; Knox, R. G.; Koven, C.; Fisher, R.

    2016-12-01

    As a key component in the climate system, old-growth tropical forests act as carbon sinks that remove CO2 from the atmosphere. However, these forests could be easily turned into C sources when disturbed. In fact, over half of tropical forests have been cleared or logged, and almost half of standing primary tropical forests are designated for timber production. Existing literature suggests that timber harvests alone could contribute up to 25% as much C losses as deforestation in Amazon. Yet, the spatial extent and recovery trajectory of disturbed forests in a changing climate are highly uncertain. This study constitutes our first attempt to quantify impacts of selective logging on water, energy, and carbon budgets in Amazon forests using the Functionally Assembled Terrestrial Ecosystem Simulator (FATES). The Community Land Model version 4.5 (CLM4.5), with and without FATES turned on, are configured to run at two flux towers established in the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA). One tower is located at in an old-growth forest (i.e. KM67) and the other is located in a selectively logged site (i.e., KM83). The three CLM4.5 options, (1) Satellite Phenology (CLM4.5-SP), (2) Century-based biogeochemical cycling with prognostic phenology (CLM4.5-BGC), and (3) CLM4.5-FATES, are spun up to equilibrium by recycling the observed meteorology at the towers, respectively. The simulated fluxes (i.e., sensible heat, latent heat, and net ecosystem exchange) are then compared to observations at KM67 to evaluate the capability of the models in capturing water and carbon dynamics in old-growth tropical forests. Our results suggest that all three models perform reasonably well in capturing the fluxes but demographic features simulated by FATES, such as distributions of diameter at breast height (DBH) and stem density (SD), are skewed heavily toward extremely large trees (e.g., > 100 cm in DBH) when compared to site surveys at the forest plots. Efforts are

  13. Nutrient enrichment and food web composition affect ecosystem metabolism in an experimental seagrass habitat.

    Science.gov (United States)

    Spivak, Amanda C; Canuel, Elizabeth A; Duffy, J Emmett; Richardson, J Paul

    2009-10-15

    Food web composition and resource levels can influence ecosystem properties such as productivity and elemental cycles. In particular, herbivores occupy a central place in food webs as the species richness and composition of this trophic level may simultaneously influence the transmission of resource and predator effects to higher and lower trophic levels, respectively. Yet, these interactions are poorly understood. Using an experimental seagrass mesocosm system, we factorially manipulated water column nutrient concentrations, food chain length, and diversity of crustacean grazers to address two questions: (1) Does food web composition modulate the effects of nutrient enrichment on plant and grazer biomasses and stoichiometry? (2) Do ecosystem fluxes of dissolved oxygen and nutrients more closely reflect above-ground biomass and community structure or sediment processes? Nutrient enrichment and grazer presence generally had strong effects on biomass accumulation, stoichiometry, and ecosystem fluxes, whereas predator effects were weaker or absent. Nutrient enrichment had little effect on producer biomass or net ecosystem production but strongly increased seagrass nutrient content, ecosystem flux rates, and grazer secondary production, suggesting that enhanced production was efficiently transferred from producers to herbivores. Gross ecosystem production (oxygen evolution) correlated positively with above-ground plant biomass, whereas inorganic nutrient fluxes were unrelated to plant or grazer biomasses, suggesting dominance by sediment microbial processes. Finally, grazer richness significantly stabilized ecosystem processes, as predators decreased ecosystem production and respiration only in the zero- and one- species grazer treatments. Overall, our results indicate that consumer presence and species composition strongly influence ecosystem responses to nutrient enrichment, and that increasing herbivore diversity can stabilize ecosystem flux rates in the face of

  14. Nutrient enrichment and food web composition affect ecosystem metabolism in an experimental seagrass habitat.

    Directory of Open Access Journals (Sweden)

    Amanda C Spivak

    2009-10-01

    Full Text Available Food web composition and resource levels can influence ecosystem properties such as productivity and elemental cycles. In particular, herbivores occupy a central place in food webs as the species richness and composition of this trophic level may simultaneously influence the transmission of resource and predator effects to higher and lower trophic levels, respectively. Yet, these interactions are poorly understood.Using an experimental seagrass mesocosm system, we factorially manipulated water column nutrient concentrations, food chain length, and diversity of crustacean grazers to address two questions: (1 Does food web composition modulate the effects of nutrient enrichment on plant and grazer biomasses and stoichiometry? (2 Do ecosystem fluxes of dissolved oxygen and nutrients more closely reflect above-ground biomass and community structure or sediment processes? Nutrient enrichment and grazer presence generally had strong effects on biomass accumulation, stoichiometry, and ecosystem fluxes, whereas predator effects were weaker or absent. Nutrient enrichment had little effect on producer biomass or net ecosystem production but strongly increased seagrass nutrient content, ecosystem flux rates, and grazer secondary production, suggesting that enhanced production was efficiently transferred from producers to herbivores. Gross ecosystem production (oxygen evolution correlated positively with above-ground plant biomass, whereas inorganic nutrient fluxes were unrelated to plant or grazer biomasses, suggesting dominance by sediment microbial processes. Finally, grazer richness significantly stabilized ecosystem processes, as predators decreased ecosystem production and respiration only in the zero- and one- species grazer treatments.Overall, our results indicate that consumer presence and species composition strongly influence ecosystem responses to nutrient enrichment, and that increasing herbivore diversity can stabilize ecosystem flux rates in

  15. Plant species and functional group combinations affect green roof ecosystem functions.

    Science.gov (United States)

    Lundholm, Jeremy; Macivor, J Scott; Macdougall, Zachary; Ranalli, Melissa

    2010-03-12

    Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green

  16. Working group 7: Ecosystems

    International Nuclear Information System (INIS)

    Verheyen, R.

    1976-01-01

    The purpose of this article is to evaluate the environmental impact of nuclear power plants. The effects of ionizing radiations, of the thermal and chemical pollution on aquatic ecosystems as well as on terrestrial ecosystems have been estimated. After a general survey of such effects and their interaction, practical conclusions in regard to determined areas such as Meuse-Escaut marine and the coast have been drawn. The contamination effects of food chains have been evaluted under deliberately pessimistic conditions with regard to the choice of the radionuclide as well as of concentration factors. Following the biodegradation conditions of the surface waters, criteria for the quality of the aquatic ecosystems have been established. Finally, attention has been paid on certain factors affecting the site selection especially within the frame of the nature conservation. The effects of cooling towers have been also considered. (G.C.)

  17. Physiological Integration Affects Expansion of an Amphibious Clonal Plant from Terrestrial to Cu-Polluted Aquatic Environments

    Science.gov (United States)

    Xu, Liang; Zhou, Zhen-Feng

    2017-03-01

    The effects of physiological integration on clonal plants growing in aquatic and terrestrial habitats have been extensively studied, but little is known about the role in the extension of amphibious clonal plants in the heterogeneous aquatic-terrestrial ecotones, especially when the water environments are polluted by heavy metals. Ramets of the amphibious clonal herb Alternanthera philoxeroides were rooted in unpolluted soil and polluted water at three concentrations of Cu. The extension of populations from unpolluted terrestrial to polluted aqueous environments mainly relied on stem elongation rather than production of new ramets. The absorbed Cu in the ramets growing in polluted water could be spread horizontally to other ramets in unpolluted soil via physiological integration and redistributed in different organs. The performances of ramets in both terrestrial and aquatic habitats were negatively correlated with Cu intensities in different organs of plants. It is concluded that physiological integration might lessen the fitness of connected ramets in heterogeneously polluted environments. The mechanical strength of the stems decreased with increasing Cu levels, especially in polluted water. We suggest that, except for direct toxicity to growth and expansion, heavy metal pollution might also increase the mechanical risk in breaking failure of plants.

  18. The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: why fine-grained terrestrial sediment is bad for coral reef ecosystems

    Science.gov (United States)

    Storlazzi, Curt; Norris, Benjamin; Rosenberger, Kurt

    2015-01-01

    Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

  19. Guidelines for Terrestrial Ecosystem Survey.

    Science.gov (United States)

    1980-05-01

    Canada Bull. 203, Biol. Ser. 73 (1966). Goodwin, G. G., Mammals of Costa Rica , Bull. Amer. Mus. Nat. Hist., Vol 87 (1946), pp 473. Hall, E. R. and W. W...Dalquest, The Mammals of Vera Cruz, Univ. Kansas Publs., Mus. Nat. Hist., Vol 14 (1963), pp 165-362. Heller, E., Mammals of the Galapagos Archipelago ...Freshwater Life (New York: Putnam, 1966). McAtec, W. L., Wildlife of the Atlantic Coast Salt Marshes, U.S. Dept. Agric., Circ. 520 (1939), pp 1-20

  20. How do land-use legacies affect ecosystem services in United States cultural landscapes?

    Science.gov (United States)

    Carly Ziter; Rose A. Graves; Monica G. Turner

    2017-01-01

    ContextLandscape-scale studies of ecosystem services (ES) have increased, but few consider land-use history. Historical land use may be especially important in cultural landscapes, producing legacies...

  1. Ecological transfer mechanisms - Terrestrial

    International Nuclear Information System (INIS)

    Martin, W.E.; Raines, Gilbert E.; Bloom, S.G.; Levin, A.A.

    1969-01-01

    Radionuclides produced by nuclear excavation detonations and released to the environment may enter a variety of biogeochemical cycles and follow essentially the same transfer pathways as their stable-element counterparts. Estimation of potential internal radiation doses to individuals and/or populations living in or near fallout-contaminated areas requires analysis of the food-chain and other ecological pathways by which radionuclides released to the environment may be returned to man. A generalized materials transfer diagram, applicable to the forest, agricultural, freshwater and marine ecosystems providing food and water to the indigenous population of Panama and Colombia in regions that could be affected by nuclear excavation of a sea-level canal between the Atlantic and Pacific Oceans, is presented. Transfer mechanisms effecting the movement of stable elements and radionuclides in terrestrial ecosystems are discussed, and methods used to simulate these processes by means of mathematical models are described to show how intake values are calculated for different radionuclides in the major ecological pathways leading to man. These data provide a basis for estimating potential internal radiation doses for comparison with the radiation protection criteria established by recognized authorities; and this, in turn, provides a basis for recommending measures to insure the radiological safety of the nuclear operation plan. (author)

  2. Solidago canadensis invasion affects soil N-fixing bacterial communities in heterogeneous landscapes in urban ecosystems in East China.

    Science.gov (United States)

    Wang, Congyan; Jiang, Kun; Zhou, Jiawei; Wu, Bingde

    2018-03-12

    Soil nitrogen-fixing bacterial communities (SNB) can increase the level of available soil N via biological N-fixation to facilitate successful invasion of several invasive plant species (IPS). Meanwhile, landscape heterogeneity can greatly enhance regional invasibility and increase the chances of successful invasion of IPS. Thus, it is important to understand the soil micro-ecological mechanisms driving the successful invasion of IPS in heterogeneous landscapes. This study performed cross-site comparisons, via metagenomics, to comprehensively analyze the effects of Solidago canadensis invasion on SNB in heterogeneous landscapes in urban ecosystems. Rhizospheric soil samples of S. canadensis were obtained from nine urban ecosystems [Three replicate quadrats (including uninvaded sites and invaded sites) for each type of urban ecosystem]. S. canadensis invasion did not significantly affect soil physicochemical properties, the taxonomic diversity of plant communities, or the diversity and richness of SNB. However, some SNB taxa (i.e., f_Micromonosporaceae, f_Oscillatoriaceae, and f_Bacillaceae) changed significantly with S. canadensis invasion. Thus, S. canadensis invasion may alter the community structure, rather than the diversity and richness of SNB, to facilitate its invasion process. Of the nine urban ecosystems, the diversity and richness of SNB was highest in farmland wasteland. Accordingly, the community invasibility of farmland wasteland may be higher than that of the other types of urban ecosystem. In brief, landscape heterogeneity, rather than S. canadensis invasion, was the strongest controlling factor for the diversity and richness of SNB. One possible reason may be the differences in soil electrical conductivity and the taxonomic diversity of plant communities in the nine urban ecosystems, which can cause notable shifts in the diversity and richness of SNB. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Assessing how green space types affect ecosystem services delivery in Porto, Portugal

    Science.gov (United States)

    Marisa Graça; Paulo Alves; João Gonçalves; David J. Nowak; Robert Hoehn; Paulo Farinha-Marques; Mario Cunha

    2018-01-01

    Significant advances have been made in identifying, quantifying and valuing multiple urban ecosystem services (UES), yet this knowledge remains poorly implemented in urban planning and management. One of the reasons for this low implementation is the insufficient thematic and spatial detail in UES research to provide guidance for urban planners and managers....

  4. Terrestrial forest management plan for Palmyra Atoll

    Science.gov (United States)

    Hathaway, Stacie A.; McEachern, Kathryn; Fisher, Robert N.

    2011-01-01

    , and though rarely documented, beach nesting could be affected by terrestrial management actions. There are various nonnative or invasive species throughout the terrestrial ecosystem. The most notable examples of terrestrial invasive species include coconut palms (Cocos nucifera) and black rats (Rattus rattus). Although it is unclear whether they are nonnative, coconut palms are currently the most dominant plant across Palmyra Atoll. They compete with native plant species for space and resources and are potentially detrimental to sea birds dependent on native vegetation for roosting and nesting habitat. This competition in turn impacts nutrient resource availability, thereby reshaping energy flow in the ecosystem. Black rats are known to prey on ground-nesting sea birds and are likely responsible for the lack of burrowing sea bird reproduction at Palmyra Atoll. In addition, they may be facilitating the invasion of other nonnative species and negatively impacting other native fauna. Although the extent and impacts of these and other nonnative and (or) invasive species are not fully understood, the extent and impacts are clearly a threat to the native species and one of the most urgent threats to the overall ecosystem integrity of Palmyra Atoll. This 'Terrestrial Forest Management Plan for Palmyra Atoll' addresses issues related to invasive species and other problems. Priority goals are established as are associated objectives and strategies. The overarching goal is to perpetuate and where possible restore terrestrial ecosystem integrity through the following techniques: 1. Habitat management: Maintain and enhance habitat to the extent possible to sustain thriving Pisonia grandis forest, coastal strand forest, endemic grassland, self-sustaining populations of sea birds, shore birds, coconut crabs, native lizards, and native insects. 2. Monitoring and assessment: Acquire information on distribution and abundance as needed for conservation of each resour

  5. How forest management affects ecosystem services, including timber production and economic return

    DEFF Research Database (Denmark)

    Duncker, Philipp S.; Raulund-Rasmussen, Karsten; Gundersen, Per

    2012-01-01

    Forest ecosystems deliver multiple goods and services and, traditionally, forest owners tend to have a high interest in goods in the form of merchantable wood. As a consequence, forest management often aims to increase timber production and economic returns through intervention into natural...... processes. However, forests provide further services, including carbon sequestration, water quantity and quality, and preservation of biodiversity. In order to develop and implement strategies for sustainable forest management, it is important to anticipate the long-term effects of different forest...... management alternatives on the ability of the forest to provide ecosystem goods and services. Management objectives might emphasize economic interests at the expense of other services. Very few attempts have been made to illustrate and evaluate quantitatively the relationship between forest goods...

  6. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    Czech Academy of Sciences Publication Activity Database

    Marek, Michal V.; Janouš, Dalibor; Taufarová, Klára; Havránková, Kateřina; Pavelka, Marian; Kaplan, Věroslav; Marková, I.

    2011-01-01

    Roč. 159, č. 5 (2011), s. 1035-1039 ISSN 0269-7491 R&D Projects: GA MŽP(CZ) SP/1A6/108/07; GA MŠk 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : carbon fluxes * net ecosystem exchange * spruce forest * beech forest * Grassland * agroecosystem * wetland * climate factors Subject RIV: EH - Ecology, Behaviour Impact factor: 3.746, year: 2011

  7. Effects of red-backed salamanders on ecosystem functions.

    Directory of Open Access Journals (Sweden)

    Daniel J Hocking

    Full Text Available Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp. likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2 plots and small-scale enclosures (2 m(2 where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2. In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders. Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

  8. Assessment of the importance of acidic fogwater and cloudwater in affecting terrestrial vegetation: Some important case studies

    Energy Technology Data Exchange (ETDEWEB)

    Irving, P.M.; Eagar, C. (National Acid Precipitation Assessment Program, Washington, DC (USA). Office of the Director of Research; Forest Service, Broomall, PA (USA). Northeastern Forest Experiment Station)

    1989-01-01

    The purpose of this paper is to present some examples of terrestrial effects of concern as case studies to demonstrate the methodology to be used for answering questions of the NAPAP Integrated Assessment. The two examples presented, one each for forestry and crops, represent what is probably the worst case'' for possible acidic rain effects on crops and forests. Both examples revolve around hypotheses centering on stress from acidic fogwater or cloudwater. Because it is likely that additional information will become available prior to the publication of the Integrated Assessment, it should be understood that the analyses and interpretations presented on the following pages are subject to change when NAPAP publishes its final Assessment in 1990. 76 refs., 3 tabs.

  9. Riparian vegetation in the alpine connectome: Terrestrial-aquatic and terrestrial-terrestrial interactions.

    Science.gov (United States)

    Zaharescu, Dragos G; Palanca-Soler, Antonio; Hooda, Peter S; Tanase, Catalin; Burghelea, Carmen I; Lester, Richard N

    2017-12-01

    Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment

  10. Radioecology of natural systems. Fifteenth annual progress report, August 1, 1976--July 31, 1977. [Plutonium transport in terrestrial ecosystems at Rocky Flats Plant with emphasis on biological effects on mule deer and coyotes

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, F.W.

    1977-08-01

    This report summarizes project activities during the period August 1, 1976 through July 31, 1977. Four major areas of effort are reported, namely plutonium behavior in a terrestrial ecosystem at Rocky Flats, mule deer and coyote studies at Rocky Flats, ecological consequences of transuranics in the terrestrial environment, and lead geochemistry of an alpine lake ecosystem. Much of the first area of effort involved the synthesis of data and preparation of manuscripts, although some new data are reported on plutonium levels in small mammals, plant uptake of plutonium from contaminated soil, and plutonium deposition rates on macroplot 1. The mule deer studies generated a substantial body of new information which will permit quantitative assessment of plutonium dispersion by deer that utilize contaminated areas. These studies involve population dynamics, movement and use patterns, food habits, ingestion rates of contaminated soil and vegetation and plutonium burdens of deer tissues. A related study of coyote food habits in summer at Rocky Flats is reported. A manuscript dealing with the question of ecological effects of transuranics was prepared. This manuscript incorporates data from Rocky Flats on characteristics of natural populations which occupy ecologically similar areas having differing levels of plutonium contamination. The lead geochemistry studies continued to generate new data but the data are not yet reported.

  11. Anthropogenic pollutants affect ecosystem services of freshwater sediments. The need for a 'triad plus x' approach

    Energy Technology Data Exchange (ETDEWEB)

    Gerbersdorf, Sabine Ulrike; Wieprecht, Silke [Stuttgart Univ. (Germany). Dept. of Hydraulic Engineering and Water Resources Management; Hollert, Henner; Brinkmann, Markus [RWTH Aachen Univ. (Germany). Dept. of Ecosystem Analysis; Schuettrumpf, Holger [RWTH Aachen Univ. (Germany). Inst. of Hydraulic Engineering and Water Resources Management; Manz, Werner [Koblenz-Landau Univ., Koblenz (Germany). Inst. for Integrated Natural Sciences

    2011-09-15

    Purpose: Freshwater sediments and their attached microbial communities (biofilms) are essential features of rivers and lakes, providing valuable ecosystem services such as nutrient recycling or self-purification which extend beyond the aquatic environment. Anthropogenic pollutants, whether from the industrial era or as a result of our contemporary lifestyles, can negatively affect these functions with hitherto unknown consequences on ecology, the economy and human health. Thus far, the singular view of the involved disciplines such as ecotoxicology, environmental microbiology, hydrology and geomorphology has prevented a deeper understanding of this emerging issue. Main features: This paper discusses briefly the progressions and the state-of-the-art methods within the disciplines of concern related to contaminated sediments, ranging from ecotoxicological test systems, microbiological/molecular approaches to unravel changes of microbial ecosystems, up to the modelling of sediment transport and sorption/desorption of associated pollutants. The first bilateral research efforts on contaminated sediments include efforts to assess ecotoxicological sediment risk including sediment mobility (i.e. ecotoxicology and engineering), enhance bioremediation potential (i.e. microbiology and ecotoxicology) or to understand biostabilisation processes of sediments by microbial assemblages (i.e. microbiology and engineering). Conclusions and perspectives: In freshwater habitats, acute, chronic and mechanism-specific toxic effects on organisms, shifts in composition, structure and functionality of benthic microbial communities, as well as the obstruction of important ecosystem services by continuously discharged and long-deposited pollutants, should be related to the in situ sediment dynamics. To achieve an improved understanding of the ecology of freshwater sediments and the impairment of their important ecosystem functions by human-derived pollutants, we suggest a 'triad plus x

  12. Forest ecosystems and environments scaling up from shoot module to watershed

    CERN Document Server

    Kohyama, Takashi; Ojima, Dennis S

    2005-01-01

    Coastal East and Southeast Asia are characterized by wet growing seasons, and species-rich forest ecosystems develop throughout the latitudinal and altitudinal gradients. In this region, the Global Change Impacts on Terrestrial Ecosystems in Monsoon Asia (TEMA) project was carried out as a unique contribution to the international project Global Change and Terrestrial Ecosystems. TEMA aimed to integrate forest ecosystem processes, from leaf physiology to meteorological budget and prediction of long-term change of vegetation composition and architecture through demographic processes. Special attention was given to watershed processes, where forest ecosystem metabolism affects the properties and biogeochemical budgets of freshwater ecosystems, and where rivers, wetlands, and lakes are subject to direct and indirect effects of environmental change. This volume presents the scaling-up concept for better understanding of ecosystem functioning.

  13. Does the uncertainty in the representation of terrestrial water flows affect precipitation predictability? A WRF-Hydro ensemble analysis for Central Europe

    Science.gov (United States)

    Arnault, Joel; Rummler, Thomas; Baur, Florian; Lerch, Sebastian; Wagner, Sven; Fersch, Benjamin; Zhang, Zhenyu; Kerandi, Noah; Keil, Christian; Kunstmann, Harald

    2017-04-01

    Precipitation predictability can be assessed by the spread within an ensemble of atmospheric simulations being perturbed in the initial, lateral boundary conditions and/or modeled processes within a range of uncertainty. Surface-related processes are more likely to change precipitation when synoptic forcing is weak. This study investigates the effect of uncertainty in the representation of terrestrial water flows on precipitation predictability. The tools used for this investigation are the Weather Research and Forecasting (WRF) model and its hydrologically-enhanced version WRF-Hydro, applied over Central Europe during April-October 2008. The WRF grid is that of COSMO-DE, with a resolution of 2.8 km. In WRF-Hydro, the WRF grid is coupled with a sub-grid at 280 m resolution to resolve lateral terrestrial water flows. Vertical flow uncertainty is considered by modifying the parameter controlling the partitioning between surface runoff and infiltration in WRF, and horizontal flow uncertainty is considered by comparing WRF with WRF-Hydro. Precipitation predictability is deduced from the spread of an ensemble based on three turbulence parameterizations. Model results are validated with E-OBS precipitation and surface temperature, ESA-CCI soil moisture, FLUXNET-MTE surface evaporation and GRDC discharge. It is found that the uncertainty in the representation of terrestrial water flows is more likely to significantly affect precipitation predictability when surface flux spatial variability is high. In comparison to the WRF ensemble, WRF-Hydro slightly improves the adjusted continuous ranked probability score of daily precipitation. The reproduction of observed daily discharge with Nash-Sutcliffe model efficiency coefficients up to 0.91 demonstrates the potential of WRF-Hydro for flood forecasting.

  14. Submergence-induced morphological, anatomical, and biochemical responses in a terrestrial species affect gas diffusion resistance and photosynthetic performance.

    Science.gov (United States)

    Mommer, Liesje; Pons, Thijs L; Wolters-Arts, Mieke; Venema, Jan Henk; Visser, Eric J W

    2005-09-01

    Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and carbohydrates would be continued photosynthesis under water, but this possibility has received only little attention. Here, we combine several techniques to investigate the consequences of anatomical and biochemical responses of the terrestrial species Rumex palustris to submergence for different aspects of photosynthesis under water. The orientation of the chloroplasts in submergence-acclimated leaves was toward the epidermis instead of the intercellular spaces, indicating that underwater CO(2) diffuses through the cuticle and epidermis. Interestingly, both the cuticle thickness and the epidermal cell wall thickness were significantly reduced upon submergence, suggesting a considerable decrease in diffusion resistance. This decrease in diffusion resistance greatly facilitated underwater photosynthesis, as indicated by higher underwater photosynthesis rates in submergence-acclimated leaves at all CO(2) concentrations investigated. The increased availability of internal CO(2) in these "aquatic" leaves reduced photorespiration, and furthermore reduced excitation pressure of the electron transport system and, thus, the risk of photodamage. Acclimation to submergence also altered photosynthesis biochemistry as reduced Rubisco contents were observed in aquatic leaves, indicating a lower carboxylation capacity. Electron transport capacity was also reduced in these leaves but not as strongly as the reduction in Rubisco, indicating a substantial increase of the ratio between electron transport and carboxylation capacity upon submergence. This novel finding suggests that this ratio may be less conservative than previously thought.

  15. Changes in canopy structure and ant assemblages affect soil ecosystem variables as a foundation species declines

    DEFF Research Database (Denmark)

    Kendrick, Joseph A.; Ribbons, Relena Rose; Classen, Aimee Taylor

    2015-01-01

    (richness and abundance) of ants increases rapidly as T. canadensis is lost from the stands. Because ants live and forage at the litter-soil interface, we hypothesized that environmental changes caused by hemlock loss (e.g., increased light and warmth at the forest floor, increased soil pH) and shifts...... in ant species composition would interact to alter soil ecosystem variables. In the Harvard Forest Hemlock Removal Experiment (HF-HeRE), established in 2003, T. canadensis in large plots were killed in place or logged and removed to mimic adelgid infestation or salvage harvesting, respectively. In 2006......, we built ant exclosure subplots within all of the canopy manipulation plots to examine direct and interactive effects of canopy change and ant assemblage composition on soil and litter variables. Throughout HF-HeRE, T. canadensis was colonized by the adelgid in 2009, and the infested trees are now...

  16. Nutrient addition differentially affects ecological processes of Avicennia germinans in nitrogen versus phosphorus limited mangrove ecosystems

    Science.gov (United States)

    Feller, Ilka C.; Lovelock, C.E.; McKee, K.L.

    2007-01-01

    Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen (N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different kinds of nutrient limitation may have different effects on ecosystem structure and function in natural systems. We compared a broad range of ecological processes to determine if these systems have different thresholds where shifts might occur in nutrient limitation. Growth responses indicated N limitation in Avicennia germinans (black mangrove) forests in the Indian River Lagoon (IRL), Florida, and P limitation at Twin Cays, Belize. When nutrient deficiency was relieved, A. germinans grew out of its stunted form by increasing wood relative to leaf biomass and shoot length relative to lateral growth. At the P-limited site, P enrichment (+P) increased specific leaf area, N resorption, and P uptake, but had no effect on P resorption. At the N-limited site, +N increased both N and P resorption, but did not alter biomass allocation. Herbivory was greater at the P-limited site and was unaffected by +P, whereas +N led to increased herbivory at the N-limited site. The responses to nutrient enrichment depended on the ecological process and limiting nutrient and suggested that N- versus P-limited mangroves do have different thresholds. +P had a greater effect on more ecological processes at Twin Cays than did +N at the IRL, which indicated that the P-limited site was more sensitive to nutrient loading. Because of this sensitivity, eutrophication is more likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL. ?? 2007 Springer Science+Business Media, LLC.

  17. Terrestrial Carbon Cycle Variability.

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2 , temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1 ) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1 ), and

  18. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates.

    Science.gov (United States)

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ(13)C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m(-2)⋅y(-1). Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Earthworm functional traits and interspecific interactions affect plant nitrogen acquisition and primary production

    NARCIS (Netherlands)

    Andriuzzi, Walter; Schmidt, Olaf; Brussaard, L.; Faber, J.H.; Bolger, T.

    2016-01-01

    We performed a greenhouse experiment to test how the functional diversity of earthworms, the dominant group of soil macro-invertebrates in many terrestrial ecosystems, affects nitrogen cycling and plant growth. Three species were chosen to represent a range of functional traits: Lumbricus terrestris

  20. Variations and trends of terrestrial NPP and its relation to climate ...

    Indian Academy of Sciences (India)

    and hydrological cycles affecting climate can be simulated. DGVMs commonly simulate a variety of plant and soil physiological processes. They can reflect the effects and responses of vegetation to climate change and get the actual climate change and changes in the terrestrial ecosystem (Olofsson and Hickler 2008).

  1. Scale-dependent diversity patterns affect spider assemblages of two contrasting forest ecosystems

    Science.gov (United States)

    Schuldt, Andreas; Assmann, Thorsten; Schaefer, Matthias

    2013-05-01

    Spiders are important generalist predators in forests. However, differences in assemblage structure and diversity can have consequences for their functional impact. Such differences are particularly evident across latitudes, and their analysis can help to generate a better understanding of region-specific characteristics of predator assemblages. Here, we analyse the relationships between species richness, family richness and functional diversity (FD) as well as α- and β-components of epigeic spider diversity in semi-natural temperate and subtropical forest sites. As expected, within-plot and overall spider species and family richness were higher in the subtropical plots. In contrast, local FD within plots was similar between sites, and differences in FD only became evident at larger spatial scales due to higher species turnover in the subtropical forests. Our study indicates that the functional effects of predator assemblages can change across spatial scales. We discuss how differences in richness and functional diversity between contrasting forest ecosystems can depend on environmental heterogeneity and the effects of species filters acting at local scales. The high turnover observed in the species-rich subtropical forests also requires a more regional perspective for the conservation of the overall diversity and the ecological functions of predators than in less diverse forests, as strategies need to account for the large spatial heterogeneity among plots.

  2. Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

    Science.gov (United States)

    Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen

    2015-01-01

    The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T. gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T. gondii by marine snails in laboratory aquaria, and to test for natural T. gondii contamination in field-collected snails. Following exposure to T. gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T. gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T. gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T. gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

  3. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Junchao [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Thanh, E-mail: bswang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Han, Shanlong [Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Pu; Zhang, Qinghua; Jiang, Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China)

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ{sup 13}C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m{sup −2}⋅y{sup −1}. Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the

  4. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    International Nuclear Information System (INIS)

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ 13 C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m −2 ⋅y −1 . Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the terrestrial

  5. Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota.

    Science.gov (United States)

    Constable, Andrew J; Melbourne-Thomas, Jessica; Corney, Stuart P; Arrigo, Kevin R; Barbraud, Christophe; Barnes, David K A; Bindoff, Nathaniel L; Boyd, Philip W; Brandt, Angelika; Costa, Daniel P; Davidson, Andrew T; Ducklow, Hugh W; Emmerson, Louise; Fukuchi, Mitsuo; Gutt, Julian; Hindell, Mark A; Hofmann, Eileen E; Hosie, Graham W; Iida, Takahiro; Jacob, Sarah; Johnston, Nadine M; Kawaguchi, So; Kokubun, Nobuo; Koubbi, Philippe; Lea, Mary-Anne; Makhado, Azwianewi; Massom, Rob A; Meiners, Klaus; Meredith, Michael P; Murphy, Eugene J; Nicol, Stephen; Reid, Keith; Richerson, Kate; Riddle, Martin J; Rintoul, Stephen R; Smith, Walker O; Southwell, Colin; Stark, Jonathon S; Sumner, Michael; Swadling, Kerrie M; Takahashi, Kunio T; Trathan, Phil N; Welsford, Dirk C; Weimerskirch, Henri; Westwood, Karen J; Wienecke, Barbara C; Wolf-Gladrow, Dieter; Wright, Simon W; Xavier, Jose C; Ziegler, Philippe

    2014-10-01

    Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed. © 2014 John Wiley & Sons Ltd.

  6. How sulfate-rich mine drainage affected aquatic ecosystem degradation in northeastern China, and potential ecological risk.

    Science.gov (United States)

    Zhao, Qian; Guo, Fen; Zhang, Yuan; Ma, Shuqin; Jia, Xiaobo; Meng, Wei

    2017-12-31

    Mining activity is an increasingly important stressor for freshwater ecosystems. However, the mechanism on how sulfate-rich mine drainage affects freshwater ecosystems is largely unknown, and its potential ecological risk has not been assessed so far. During 2009-2016, water and macroinvertebrate samples from 405 sample sites were collected along the mine drainage gradient from circum-neutral to alkaline waters in Hun-Tai River, Northeastern China. Results of linear regressions showed that sulfate-rich mine drainage was significantly positively correlated with the constituents typically derived from rock weathering (Ca 2+ , Mg 2+ and HCO 3 - +CO 3 2- ); the diversity of intolerant stream macroinvertebrates exhibited a steep decline along the gradient of sulfate-rich mine drainage. Meanwhile, stressor-response relationships between sulfate-rich mine drainage and macroinvertebrate communities were explored by two complementary statistical approaches in tandem (Threshold Indicator Taxa Analysis and the field-based method developed by USEPA). Results revealed that once stream sulfate concentrations in mine drainage exceeded 35mg/L, significant decline in the abundance of intolerant macroinvertebrate taxa occurred. An assessment of ecological risk posed by sulfate-rich mine drainage was conducted based on a tiered approach consisting of simple deterministic method (Hazard Quotient, HQ) to probabilistic method (Joint Probability Curve, JPC). Results indicated that sulfate-rich mine drainage posed a potential risk, and 64.62-84.88% of surface waters in Hun-Tai River exist serious risk while 5% threshold (HC 05 ) and 1% threshold (HC 01 ) were set up to protect macroinvertebrates, respectively. This study provided us a better understanding on the impacts of sulfate-rich mine drainage on freshwater ecosystems, and it would be helpful for future catchment management to protect streams from mining activity. Copyright © 2017. Published by Elsevier B.V.

  7. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    OpenAIRE

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-01-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomas...

  8. Climatic Versus Biotic Constraints on Carbon and Water Fluxes in Seasonally Drought-affected Ponderosa Pine Ecosystems. Chapter 2

    Science.gov (United States)

    Schwarz, P. A.; Law, B. E.; Williams, M.; Irvine, J.; Kurpius, M.; Moore, D.

    2005-01-01

    We investigated the relative importance of climatic versus biotic controls on gross primary production (GPP) and water vapor fluxes in seasonally drought-affected ponderosa pine forests. The study was conducted in young (YS), mature (MS), and old stands (OS) over 4 years at the AmeriFlux Metolius sites. Model simulations showed that interannual variation of GPP did not follow the same trends as precipitation, and effects of climatic variation were smallest at the OS (50%), and intermediate at the YS (drought and interannual climatic variation. Interannual variation of net ecosystem exchange (NEE) was also lowest at the OS, where NEE is controlled more by interannual variation of ecosystem respiration, 70% of which is from soil, than by the variation of GPP, whereas variation in GPP is the primary reason for interannual changes in NEE at the YS and MS. Across spatially heterogeneous landscapes with high frequency of younger stands resulting from natural and anthropogenic disturbances, interannual climatic variation and change in leaf area are likely to result in large interannual variation in GPP and NEE.

  9. The false promises of coal exploitation: How mining affects herdsmen well-being in the grassland ecosystems of Inner Mongolia

    International Nuclear Information System (INIS)

    Dai, G.S.; Ulgiati, S.; Zhang, Y.S.; Yu, B.H.; Kang, M.Y.; Jin, Y.; Dong, X.B.; Zhang, X.S.

    2014-01-01

    The grasslands of Inner Mongolia are not only the source of the necessary resources for the survival and development of herdsmen, but also represent a significant green ecological barrier in North China. Coal-mining production is important in maintaining GDP growth in Inner Mongolia. However, over-exploitation has created serious problems, such as pollution of the environment and significant decreases in grassland ecosystem services, in addition to impacting the well-being of herdsmen and other humans. Based on questionnaires survey performed among 864 herdsmen addressing the relationship between coal exploitation in grasslands and human well-being in Xilinguole League in Inner Mongolia, we found that (1) coal resource exploitation in these grasslands does not benefit the herdsmen by increasing their income; (2) the rapid development of this resource has not obviously materially improved the life of the herdsmen; and (3) these activities have increased the risks that herdsman will have to endure in the future. Overall, coal resource exploitation in grasslands has more negative than positive effects on the well-being of herdsmen. We propose the conservation of coal resources and improvement of ecological compensation should be carried out without blindly pursuing economic growth, instead of focusing on economic development and structural adjustments. - Highlights: • Evaluation of the human well-being of the Xilinguole grassland, Inner Mongolia, China. • Impact of mining affects herdsmen well-being in grassland ecosystem. • Quantity of questionnaires survey. • Addressing the relationship between coal exploitation in grasslands and human well-being

  10. 8.0 Integrating the effect of terrestrial ecosystem health and land use on the hydrology, habitat, and water quality of the Delaware River and estuary

    Science.gov (United States)

    Peter S. Murdoch; John L. Hom; Yude Pan; Jeffrey M. Fischer

    2008-01-01

    To complete the collaborative monitoring study of forested landscapes within the DRB, regional perspective on the cumulative effect of different disturbances on overall ecosystem health. This section describes two modeling activities used as integrating tools for the CEMRI database and a validation system that used nested river monitoring stations.

  11. Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem; Elementos metalicos traza en caracoles terrestres Helix aspersa de un ecosistema semiarido

    Energy Technology Data Exchange (ETDEWEB)

    Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Morton, O.; Armienta, M.A.; Hernandez, E. [IGF-UNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2001-07-01

    The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

  12. A new plant assemblage (microfossil and megafossil) from the Lower Old Red Sandstone of the Anglo-Welsh Basin: its implications for the palaeoecology of early terrestrial ecosystems.

    Science.gov (United States)

    Wellman; Habgood; Jenkins; Richardson

    2000-05-01

    Lower Old Red Sandstone deposits penetrated by a series of cored boreholes near Newport (South Wales) have been sedimentologically logged, and recovered plant assemblages (microfossil and megafossil) investigated. Sedimentological logging indicates that the deposits are typical of the extensive terrestrial-fluviatile floodplain deposits of the Anglo-Welsh Basin. Palynomorph assemblages have been recovered from a number of horizons and comprise entirely terrestrial forms (spores and phytodebris). They essentially represent a single assemblage, belonging to the middle subzone of the micrornatus-newportensis sporomorph assemblage biozone, and indicate an Early Devonian (mid-Lochkovian) age. The new biostratigraphical data enables correlation with other Lower Old Red Sandstone deposits of the Anglo-Welsh Basin, and the deposits are assigned to the lower part of the St. Maughan's Group. A plant megafossil/mesofossil assemblage recovered from one of the spore-bearing horizons includes a zosterophyll assigned to Zosterophyllum cf. fertile. This is the earliest reported zosterophyll from the Anglo-Welsh Basin. The new palynological/palaeobotanical data provide important information on the palaeoecology and palaeobiogeography of the vegetation of the southeastern margin of the Old Red Sandstone continent during Lochkovian times. Palaeogeographical variation in the distribution of plant microfossils and megafossils is interpreted as reflecting differences between the flora of the lowland floodplain and inland intermontaine basins, although this is to a certain extent overprinted by variation due to localized differences in environmental conditions.

  13. Radiation dose assessment for the biota of terrestrial ecosystems in the shoreline zone of the Chernobyl nuclear power plant cooling pond.

    Science.gov (United States)

    Oskolkov, Boris Ya; Bondarkov, Mikhail D; Gaschak, Sergey P; Maksimenko, Andrey M; Hinton, Thomas G; Coughlin, Daniel; Jannik, G Timothy; Farfán, Eduardo B

    2011-10-01

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. This paper addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90Sr and 137Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to draw down naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  14. Radiation Dose Assessment For The Biota Of Terrestrial Ecosystems In The Shoreline Zone Of The Chernobyl Nuclear Power Plant Cooling Pond

    International Nuclear Information System (INIS)

    Farfan, E.; Jannik, T.

    2011-01-01

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90 Sr and 137 Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  15. Does Bt maize cultivation affect the non-target insect community in the agro ecosystem?

    Directory of Open Access Journals (Sweden)

    Daniela Chaves Resende

    2016-03-01

    Full Text Available ABSTRACT The cultivation of genetically modified crops in Brazil has led to the need to assess the impacts of this technology on non-target species. Under field conditions, the potential effect on insect biodiversity was evaluated by comparing a homogeneous corn field with conventional and transgenic maize, expressing different Bt proteins in seven counties of Minas Gerais, Brazil. The richness pattern of non-target insect species, secondary pests and natural enemies were observed. The results do not support the hypothesis that Bt protein affects insect biodiversity. The richness and diversity data of insects studied were dependent on the location and other factors, such as the use of insecticides, which may be a major factor where they are used.

  16. Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the Mediterranean Basin: Current research and future directions.

    Science.gov (United States)

    Ochoa-Hueso, Raúl; Munzi, Silvana; Alonso, Rocío; Arróniz-Crespo, María; Avila, Anna; Bermejo, Victoria; Bobbink, Roland; Branquinho, Cristina; Concostrina-Zubiri, Laura; Cruz, Cristina; Cruz de Carvalho, Ricardo; De Marco, Alessandra; Dias, Teresa; Elustondo, David; Elvira, Susana; Estébanez, Belén; Fusaro, Lina; Gerosa, Giacomo; Izquieta-Rojano, Sheila; Lo Cascio, Mauro; Marzuoli, Riccardo; Matos, Paula; Mereu, Simone; Merino, José; Morillas, Lourdes; Nunes, Alice; Paoletti, Elena; Paoli, Luca; Pinho, Pedro; Rogers, Isabel B; Santos, Arthur; Sicard, Pierre; Stevens, Carly J; Theobald, Mark R

    2017-08-01

    Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O 3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. African dust carries microbes across the ocean: are they affecting human and ecosystem health?

    Science.gov (United States)

    Kellogg, Christina A.; Griffin, Dale W.

    2003-01-01

    Atmospheric transport of dust from northwest Africa to the western Atlantic Ocean region may be responsible for a number of environmental hazards, including the demise of Caribbean corals; red tides; amphibian diseases; increased occurrence of asthma in humans; and oxygen depletion (eutrophication) in estuaries. Studies of satellite images suggest that hundreds of millions of tons of dust are trans-ported annually at relatively low altitudes across the Atlantic Ocean to the Caribbean Sea and southeastern United States. The dust emanates from the expanding Sahara/Sahel desert region in Africa and carries a wide variety of bacteria and fungi. The U.S. Geological Survey, in collaboration with the NASA/Goddard Spaceflight Center, is conducting a study to identify microbes--bacteria, fungi, viruses--transported across the Atlantic in African soil dust. Each year, millions of tons of desert dust blow off the west African coast and ride the trade winds across the ocean, affecting the entire Caribbean basin, as well as the southeastern United States. Of the dust reaching the U.S., Florida receives about 50 percent, while the rest may range as far north as Maine or as far west as Colorado. The dust storms can be tracked by satellite and take about one week to cross the Atlantic.

  18. Technical progress report of biological research on the Volcanic Island Surtsey and environment for the year 1976. [Recovery of terrestrial ecosystem on volcanic island following volcano eruption

    Energy Technology Data Exchange (ETDEWEB)

    Fridriksson, S.

    1976-01-01

    The study involves the terrestrial biological research on the volcanic island, Surtsey, off the coast of Iceland and the neighbouring islands and environs of the Westman Islands, which are situated on the Mid-Atlantic Ridge. An eruption of the volcano in 1973 is studied. The topographical changes on Surtsey were studied in August 1976. It is evident that the southwestern side is constantly being eroded and that the island decreases in area of some 7.5 hectares per year. Results are reported from studies of microorganisms, algae, lichens, moss, vascular plants, insects, birds, and soil, and the nitrogen cycle. Emphasis was placed on revegetation and recolonization of plants, insects, and sea birds.

  19. Terrestrial carbon-nitrogen interactions across time-scales

    Science.gov (United States)

    Zaehle, Sönke; Sickel, Kerstin

    2017-04-01

    Through its role in forming amino acids, nitrogen (N) plays a fundamental role in terrestrial biogeochemistry, affecting for instance the photosynthetic rate of a leaf, and the amount of leaf area of a plant; with further consequences for quasi instantaneous terrestrial biophysical properties and fluxes. Because of the high energy requirements of transforming atmospheric N2 to biologically available form, N is generally thought to be limiting terrestrial productivity. Experimental evidence and modelling studies suggest that in temperate and boreal ecosystems, this N-"limitation" affects plant production at scales from days to decades, and potentially beyond. Whether these interactions play a role at longer timescales, such as during the transition from the last glacial maximum to the holocene, is currently unclear. To address this question, we present results from a 22000 years long simulation with dynamic global vegetation model including a comprehensive treatment of the terrestrial carbon and nitrogen balance and their interactions (using the OCN-DGVM) driven by monthly, transient climate forcing obtained from the CESM climate model (TRACE). OCN couples carbon and nitrogen processes at the time-scale of hours, but simulates a comprehensive nitrogen balance as well as vegetation dynamics with time-scales of centuries and beyond. We investigate in particular, whether (and at with time scale) carbon-nitrogen interactions cause important lags in the response of the terrestrial biosphere to changed climate, and which processes (such as altered N inputs from fixation or altered losses through leaching and denitrification) contribute to these lags.

  20. The terrestrial silica pump.

    Directory of Open Access Journals (Sweden)

    Joanna C Carey

    Full Text Available Silicon (Si cycling controls atmospheric CO(2 concentrations and thus, the global climate, through three well-recognized means: chemical weathering of mineral silicates, occlusion of carbon (C to soil phytoliths, and the oceanic biological Si pump. In the latter, oceanic diatoms directly sequester 25.8 Gton C yr(-1, accounting for 43% of the total oceanic net primary production (NPP. However, another important link between C and Si cycling remains largely ignored, specifically the role of Si in terrestrial NPP. Here we show that 55% of terrestrial NPP (33 Gton C yr(-1 is due to active Si-accumulating vegetation, on par with the amount of C sequestered annually via marine diatoms. Our results suggest that similar to oceanic diatoms, the biological Si cycle of land plants also controls atmospheric CO(2 levels. In addition, we provide the first estimates of Si fixed in terrestrial vegetation by major global biome type, highlighting the ecosystems of most dynamic Si fixation. Projected global land use change will convert forests to agricultural lands, increasing the fixation of Si by land plants, and the magnitude of the terrestrial Si pump.

  1. Evaluating the effects of terrestrial ecosystems, climate and carbon dioxide on weathering over geological time: a global-scale process-based approach

    Science.gov (United States)

    Taylor, Lyla L.; Banwart, Steve A.; Valdes, Paul J.; Leake, Jonathan R.; Beerling, David J.

    2012-01-01

    Global weathering of calcium and magnesium silicate rocks provides the long-term sink for atmospheric carbon dioxide (CO2) on a timescale of millions of years by causing precipitation of calcium carbonates on the seafloor. Catchment-scale field studies consistently indicate that vegetation increases silicate rock weathering, but incorporating the effects of trees and fungal symbionts into geochemical carbon cycle models has relied upon simple empirical scaling functions. Here, we describe the development and application of a process-based approach to deriving quantitative estimates of weathering by plant roots, associated symbiotic mycorrhizal fungi and climate. Our approach accounts for the influence of terrestrial primary productivity via nutrient uptake on soil chemistry and mineral weathering, driven by simulations using a dynamic global vegetation model coupled to an ocean–atmosphere general circulation model of the Earth's climate. The strategy is successfully validated against observations of weathering in watersheds around the world, indicating that it may have some utility when extrapolated into the past. When applied to a suite of six global simulations from 215 to 50 Ma, we find significantly larger effects over the past 220 Myr relative to the present day. Vegetation and mycorrhizal fungi enhanced climate-driven weathering by a factor of up to 2. Overall, we demonstrate a more realistic process-based treatment of plant fungal–geosphere interactions at the global scale, which constitutes a first step towards developing ‘next-generation’ geochemical models. PMID:22232768

  2. Terrestrial ecosystem recovery - Modelling the effects of reduced acidic inputs and increased inputs of sea-salts induced by global change

    DEFF Research Database (Denmark)

    Beier, C.; Moldan, F.; Wright, R.F.

    2003-01-01

    to 3 large-scale "clean rain" experiments, the so-called roof experiments at Risdalsheia, Norway; Gardsjon, Sweden, and Klosterhede, Denmark. Implementation of the Gothenburg protocol will initiate recovery of the soils at all 3 sites by rebuilding base saturation. The rate of recovery is small...... and base saturation increases less than 5% over the next 30 years. A climate-induced increase in storm severity will increase the sea-salt input to the ecosystems. This will provide additional base cations to the soils and more than double the rate of the recovery, but also lead to strong acid pulses...... following high sea-salt inputs as the deposited base cations exchange with the acidity stored in the soil. Future recovery of soils and runoff at acidified catchments will thus depend on the amount and rate of reduction of acid deposition, and in the case of systems near the coast, the frequency...

  3. Working group 4: Terrestrial

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A working group at a Canada/USA symposium on climate change and the Arctic identified major concerns and issues related to terrestrial resources. The group examined the need for, and the means of, involving resource managers and users at local and territorial levels in the process of identifying and examining the impacts and consequences of climatic change. Climatic change will be important to the Arctic because of the magnitude of the change projected for northern latitudes; the apparent sensitivity of its terrestrial ecosystems, natural resources, and human support systems; and the dependence of the social, cultural, and economic welfare of Arctic communities, businesses, and industries on the health and quality of their environment. Impacts of climatic change on the physical, biological, and associated socio-economic environment are outlined. Gaps in knowledge needed to quantify these impacts are listed along with their relationships with resource management. Finally, potential actions for response and adaptation are presented

  4. Arsenic species in ecosystems affected by arsenic-rich spring water near an abandoned mine in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.T. [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of); Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, H.O., E-mail: dunee@kbsi.re.k [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, C. [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Woo, N.C., E-mail: ncwoo@yonsei.ac.k [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of)

    2009-12-15

    The objectives of this study were to quantitatively estimate the distribution of arsenic with its speciation and to identify potential pathways for transformation of arsenic species from samples of water, sediments, and plants in the ecosystem affected by the Cheongog Spring, where As(V) concentration reached levels up to 0.270 mg L{sup -1}. After flowing about 100 m downstream, the arsenic level showed a marked reduction to 0.044 mg L{sup -1} (about 84% removal) without noticeable changes in major water chemistry. The field study and laboratory hydroponic experiments with the dominant emergent plants along the creek (water dropwort and thunbergian smartweed) indicated that arsenic distribution, reduction, and speciation appear to be controlled by, (i) sorption onto stream sediments in exchangeable fractions, (ii) bioaccumulation by and possible release from emergent plants, and (iii) transformation of As(V) to As(III) and organic species through biological activities. - Biogeochemical reactions with emergent plants and sediments control the fate of arsenic along creeks originating from a high-As Spring.

  5. Rising pCO2in Freshwater Ecosystems Has the Potential to Negatively Affect Predator-Induced Defenses in Daphnia.

    Science.gov (United States)

    Weiss, Linda C; Pötter, Leonie; Steiger, Annika; Kruppert, Sebastian; Frost, Uwe; Tollrian, Ralph

    2018-01-22

    Anthropogenically released CO 2 accumulates in the global carbon cycle and is anticipated to imbalance global carbon fluxes [1]. For example, increased atmospheric CO 2 induces a net air-to-sea flux where the oceans take up large amounts of atmospheric CO 2 (i.e., ocean acidification [2-5]). Research on ocean acidification is ongoing, and studies have demonstrated the consequences for ecosystems and organismal biology with major impacts on marine food webs, nutrient cycles, overall productivity, and biodiversity [6-9]. Yet, surprisingly little is known about the impact of anthropogenically caused CO 2 on freshwater systems due to their more complex biogeochemistry. The current consensus, yet lacking data evidence, is that anthropogenic CO 2 does indeed affect freshwater carbon hydrogeochemistry, causing increased pCO 2 in freshwater bodies [10-13]. We analyzed long-term data from four freshwater reservoirs and observed a continuous pCO 2 increase associated with a decrease in pH, indicating that not only the oceans but also inland waters are accumulating CO 2 . We tested the effect of pCO 2 -dependent freshwater acidification using the cosmopolite crustacean Daphnia. For general validity, control pCO 2 -levels were based on the present global pCO 2 average. Treatments were selected with very high pCO 2 levels, assuming a continuous non-linear increase of pCO 2 , reflecting worst-case-scenario future pCO 2 levels. Such levels of elevated pCO 2 reduced the ability of Daphnia to sense its predators and form adequate inducible defenses. We furthermore determined that pCO 2 and not the resulting reduction in pH impairs predator perception. If pCO 2 alters chemical communication between freshwater species, this perturbs intra- and interspecific information transfer, which may affect all trophic levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The effect of anthropogenic contaminations (PAH, PCB) on terrestrial annelids in conurban ecosystems. Final report; Einfluss von anthropogenen Schadstoffen (PAK und PCB) auf terrestrische Invertebraten urbaner Oekosysteme. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Achazi, R.K.; Beylich, A.; Chroszcz, G.; Dueker, C.; Heck, M.; Henneken, M.; Flenner, C.; Froehlich, E.; Garbers, U.; Khan, M.A.; Kreibich, M.; Kronshage, J.; Philippe, L.; Pilz, C.; Rothe, B.; Schabedoth, E.; Schaub, K.; Scheiwe, E.; Schmid, C.; Steudel, I.; Struwe, M.; Throl, C.; Wuertz, S. [Freie Univ. Berlin (Germany); Back, H.; Naehring, D.; Thielemann, U. [Gesellschaft fuer Angewandte Oekologie und Umweltplanung mbH, Nussloch (Germany)

    1997-09-23

    The project was conducted from August 1993 until May 1997. The objectives were (a) an elaboration of effect concentrations and index values for organic contaminants (PAH, PCB) and heavy metals in soil of conurbations for the community of decomposers, (b) the improvement of a biotest system for the evaluation of the habitat function of contaminated soils and (c) to obtain informations concerning a controlled utilization of contaminated areas. For that purpose field investigations in former sewage water irrigation areas of Berlin, Germany, concerning the abundance, species composition and dominance structure of terrestrial annelids (Enchytraeids, Lumbricids) were performed, as well as bioassays using contaminated soils of these sites and soils spiked with bezo(a)pyrene, fluoranthene, PCB 52, Cd and Cu and experiments on accumulation, elimination and biotransformation in annelids. 12 of the 17 sites investigated lacked earthworms, while only 2 sites lacked enchytraeids. The abundance of enchytraeids was in the range of 500 to 12.500/m{sup 2}, compared to 25.000 to 280.000/m{sup 2} on reference sites. The hostility of the soils of former irrigation fields to annelids was confirmed by lamina bait tests and by bioassays with Enchytraeus crypticus, E. albidus, E. buchholzi and Eisenia f. fetida. The ecotoxicity of the combined contaminants was enforced by the acidity and the degradation of the soils. The toxicity of organic and inorganic contaminants to terrestrial annelids was definitely proved by reproduction tests in the agar test system. The applied methods of investigation can be used for evaluation of contaminated soils. (orig.) [Deutsch] Das Projekt wurde von August 1993 bis Mai 1997 durchgefuehrt. Ziele waren die Erarbeitung (a) von Wirkschwellen fuer organische Schadstoffgruppen (PAK, PCB) und Schwermetalle im Boden fuer Destruenten urbaner Oekosysteme, (b) von Biotestsystemen zur Bewertung der Lebensraumfunktion belasteter Boeden und (c) von Hinweisen zur

  7. Climate and land use change impacts on global terrestrial ecosystems, fire, and river flows in the HadGEM2-ES Earth System Model using the Representative Concentration Pathways

    Science.gov (United States)

    Betts, R. A.; Golding, N.; Gonzalez, P.; Gornall, J.; Kahana, R.; Kay, G.; Mitchell, L.; Wiltshire, A.

    2013-04-01

    A new generation of an Earth System Model now includes a number of land surface processes directly relevant to analyzing potential impacts of climate change. This model, HadGEM2-ES, allows us to assess the impacts of climate change, multiple interactions, and feedbacks as the model is run. This paper discusses the results of century-scale HadGEM2-ES simulations from an impacts perspective-specifically, terrestrial ecosystems and water resources-for four different scenarios following the Representative Concentration Pathways (RCPs), being used for next assessment report of the Intergovernmental Panel on Climate Change (IPCC). Over the 21st Century, simulated changes in global and continential-scale terrestrial ecosystems due to climate change appear to be very similar in all 4 RCPs, even though the level of global warming by the end of the 21st Century ranges from 2 °C in the lowest scenario to 5.5° in the highest. A warming climate generally favours broadleaf trees over needleleaf, needleleaf trees over shrubs, and shrubs over herbaceous vegetation, resulting in a poleward shift of temperate and boreal forests and woody tundra in all scenarios. Although climate related changes are slightly larger in scenarios of greater warming, the largest differences between scenarios arise at regional scales as a consequence of different patterns of anthropogenic land cover change. In the model, the scenario with the lowest global warming results in the most extensive decline in tropical forest cover due to a large expansion of agriculture. Under all four RCPs, fire potential could increase across extensive land areas, particularly tropical and sub-tropical latitudes. River outflows are simulated to increase with higher levels of CO2 and global warming in all projections, with outflow increasing with mean temperature at the end of the 21st Century at the global scale and in North America, Asia, and Africa. In South America, Europe, and Australia, the relationship with climate

  8. Unifying Dynamic Prognostic Phenology, Heterogeneous Soil and Vegetation Fluxes, and Ecosystem Biomass and Carbon Stocks To Predict the Terrestrial Carbon Cycle and Land-Atmosphere Exchanges in the Simple Biosphere Model (SiB4)

    Science.gov (United States)

    Haynes, K. D.; Baker, I. T.; Denning, S.

    2016-12-01

    Future climate projections require process-based models that incorporate the mechanisms and feedbacks controlling the carbon cycle. Over the past three decades, land surface models have been key contributors to Earth system models, evolving from predicting latent (LE) and sensible (SH) heat fluxes to energy and water budgets, momentum transfer, and terrestrial carbon exchange and storage. This study presents the latest version of the Simple Biosphere Model (SiB4), which builds on a compilation of previous versions and adds a new mechanistic-based scheme that fully predicts the terrestrial carbon cycle. The main SiB4 updates can be summarized as follows: (i) Incorporation of carbon pools that use new respiration and transfer methods, (ii) Creation of a new dynamic phenology scheme that uses mechanistic-based seasonal stages, and (iii) Unification of carbon pools, phenology and disturbance to close the carbon cycle. SiB4 removes the dependence on satellite-based vegetation indices, and instead uses a single mathematical framework to prognose self-consistent land-atmosphere exchanges of carbon, water, energy, radiation, and momentum, as well as carbon storage. Since grasslands cover 30% of land and are highly seasonal, we investigated forty grass sites. Diurnal cycles of gross primary productivity (GPP), ecosystem respiration (RE), net ecosystem exchange (NEE), LE and SH have third-quartile root mean squared (RMS) errors less than 2.0 µmol m-2 s-1, 1.9 µmol m-2 s-1, 2.0 µmol m-2 s-1, 42 W m-2, and 78 W m-2, respectively. On the synoptic timeframe, all sites have significant LE correlation coefficients of non-seasonal daily data; and all but one have significant SH correlations. Mean seasonal cycles for leaf area index (LAI), GPP, RE, LE, and SH have third-quartile normalized RMS errors less than 32%, 25%, 28%, 16%, and 48%, respectively. On multi-year timescales, daily correlations of LAI, GPP, RE, and LE are all statistically significant, with third-quartile RMS

  9. Application of the 15N-Gas Flux method for measuring in situ N2 and N2O fluxes due to denitrification in natural and semi-natural terrestrial ecosystems and comparison with the acetylene inhibition technique

    Science.gov (United States)

    Sgouridis, F.; Ullah, S.; Stott, A.

    2015-08-01

    Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. 15N tracer approaches can provide in situ measurements of both N2 and N2O simultaneously, but their use has been limited to fertilised agro-ecosystems due to the need for large 15N additions in order to detect 15N2 production against the high atmospheric N2. For 15N-N2 analyses, we have used an "in house" laboratory designed and manufactured N2 preparation instrument which can be interfaced to any commercial continuous flow isotope ratio mass spectrometer (CF-IRMS). The N2 prep unit has gas purification steps, a copper based reduction furnace, and allows the analysis of small gas injection volumes (4 μL) for 15N-N2 analysis. For the analysis of N2O, an automated Tracegas Pre-concentrator (Isoprime Ltd) coupled to an IRMS was used to measure the 15N-N2O (4 mL gas injection volume). Consequently, the coefficient of variation for the determination of isotope ratios for N2 in air and in standard N2O (0.5 ppm) was better than 0.5 %. The 15N Gas-Flux method was adapted for application in natural and semi-natural land use types (peatlands, forests and grasslands) by lowering the 15N tracer application rate to 0.04-0.5 kg 15N ha-1. For our chamber design (volume / surface = 8:1) and a 20 h incubation period, the minimum detectable flux rates were 4 μg N m-2 h-1 and 0.2 ng N m-2 h-1 for the N2 and N2O fluxes respectively. The N2 flux ranged between 2.4 and 416.6 μg N m-2 h-1, and the grassland soils showed on average 3 and 14 times higher denitrification rates than the woodland and organic soils respectively. The N2O flux was on average 20 to 200 times lower than the N2 flux, while the denitrification product ratio (N2O/N2 + N2O) was low, ranging between 0.03 and 13 %. Total denitrification rates measured by the acetylene inhibition technique under the same field conditions

  10. Application of the 15N gas-flux method for measuring in situ N2 and N2O fluxes due to denitrification in natural and semi-natural terrestrial ecosystems and comparison with the acetylene inhibition technique

    Science.gov (United States)

    Sgouridis, Fotis; Stott, Andrew; Ullah, Sami

    2016-03-01

    Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. 15N tracer approaches can provide in situ measurements of both N2 and N2O simultaneously, but their use has been limited to fertilized agro-ecosystems due to the need for large 15N additions in order to detect 15N2 production against the high atmospheric N2. For 15N-N2 analyses, we have used an "in-house" laboratory designed and manufactured N2 preparation instrument which can be interfaced to any commercial continuous flow isotope ratio mass spectrometer (CF-IRMS). The N2 prep unit has gas purification steps and a copper-based reduction furnace, and allows the analysis of small gas injection volumes (4 µL) for 15N-N2 analysis. For the analysis of N2O, an automated Tracegas Preconcentrator (Isoprime Ltd) coupled to an IRMS was used to measure the 15N-N2O (4 mL gas injection volume). Consequently, the coefficient of variation for the determination of isotope ratios for N2 in air and in standard N2O (0.5 ppm) was better than 0.5 %. The 15N gas-flux method was adapted for application in natural and semi-natural land use types (peatlands, forests, and grasslands) by lowering the 15N tracer application rate to 0.04-0.5 kg 15N ha-1. The minimum detectable flux rates were 4 µg N m-2 h-1 and 0.2 ng N m-2 h-1 for the N2 and N2O fluxes respectively. Total denitrification rates measured by the acetylene inhibition technique in the same land use types correlated (r = 0.58) with the denitrification rates measured under the 15N gas-flux method, but were underestimated by a factor of 4, and this was partially attributed to the incomplete inhibition of N2O reduction to N2, under a relatively high soil moisture content, and/or the catalytic NO decomposition in the presence of acetylene. Even though relatively robust for in situ denitrification measurements, methodological

  11. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

    Science.gov (United States)

    Hayes, Daniel J.; Turner, David P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; de Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner A.; Jacobson, Andrew R.; Huntzinger, Deborah N.; Pan, Yude; Post, W. Mac; Cook, Robert B.

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000–2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 TgC yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 TgC yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 TgC yr-1 and -931 TgC yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 TgC yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  12. Marine and terrestrial factors affecting Adélie penguin Pygoscelis adeliae chick growth and recruitment off the western Antarctic Peninsula

    Science.gov (United States)

    Chapman, Erik W.; Hofmann, Eileen E.; Patterson, Donna L.; Ribic, Christine A.; Fraser, William R.

    2011-01-01

    An individual-based bioenergetics model that simulates the growth of an Adélie penguin Pygoscelis adeliaechick from hatching to fledging was used to assess marine and terrestrial factors that affect chick growth and fledging mass off the western Antarctic Peninsula. Simulations considered the effects on Adélie penguin fledging mass of (1) modification of chick diet through the addition of Antarctic silverfish Pleuragramma antarcticum to an all-Antarctic krillEuphausia superba diet, (2) reduction of provisioning rate which may occur as a result of an environmental stress such as reduced prey availability, and (3) increased thermoregulatory costs due to wetting of chicks which may result from increased precipitation or snow-melt in colonies. Addition of 17% Antarctic silverfish of Age-Class 3 yr (AC3) to a penguin chick diet composed of Antarctic krill increased chick fledging mass by 5%. Environmental stress that results in >4% reduction in provisioning rate or wetting of just 10% of the chick’s surface area decreased fledging mass enough to reduce the chick’s probability of successful recruitment. The negative effects of reduced provisioning and wetting on chick growth can be compensated for by inclusion of Antarctic silverfish of AC3 and older in the chick diet. Results provide insight into climate-driven processes that influence chick growth and highlight a need for field research designed to investigate factors that determine the availability of AC3 and older Antarctic silverfish to foraging Adélie penguins and the influence of snowfall on chick wetting, thermoregulation and adult provisioning rate.

  13. Effects of Timber Harvests and Silvicultural Edges on Terrestrial Salamanders

    Science.gov (United States)

    MacNeil, Jami E.; Williams, Rod N.

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years. Long

  14. Metabolic theory predicts whole-ecosystem properties.

    Science.gov (United States)

    Schramski, John R; Dell, Anthony I; Grady, John M; Sibly, Richard M; Brown, James H

    2015-02-24

    Understanding the effects of individual organisms on material cycles and energy fluxes within ecosystems is central to predicting the impacts of human-caused changes on climate, land use, and biodiversity. Here we present a theory that integrates metabolic (organism-based bottom-up) and systems (ecosystem-based top-down) approaches to characterize how the metabolism of individuals affects the flows and stores of materials and energy in ecosystems. The theory predicts how the average residence time of carbon molecules, total system throughflow (TST), and amount of recycling vary with the body size and temperature of the organisms and with trophic organization. We evaluate the theory by comparing theoretical predictions with outputs of numerical models designed to simulate diverse ecosystem types and with empirical data for real ecosystems. Although residence times within different ecosystems vary by orders of magnitude-from weeks in warm pelagic oceans with minute phytoplankton producers to centuries in cold forests with large tree producers-as predicted, all ecosystems fall along a single line: residence time increases linearly with slope = 1.0 with the ratio of whole-ecosystem biomass to primary productivity (B/P). TST was affected predominantly by primary productivity and recycling by the transfer of energy from microbial decomposers to animal consumers. The theory provides a robust basis for estimating the flux and storage of energy, carbon, and other materials in terrestrial, marine, and freshwater ecosystems and for quantifying the roles of different kinds of organisms and environments at scales from local ecosystems to the biosphere.

  15. Terrestrial Analogs to Mars

    Science.gov (United States)

    Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.

    2002-08-01

    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  16. The circumpolar biodiversity monitoring program - Terrestrial plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Circumpolar Biodiversity Monitoring Program, CBMP, Terrestrial Plan, www.caff.is/terrestrial, is a framework to focus and coordinate monitoring of terrestrial biodiversity across the Arctic. The goal of the plan is to improve the collective ability of Arctic traditional knowledge (TK) holders......, northern communities, and scientists to detect, understand and report on long-term change in Arctic terrestrial ecosystems and biodiversity. This presentation will outline the key management questions the plan aims to address and the proposed nested, multi-scaled approach linking targeted, research based...... monitoring with survey-based monitoring and remotely sensed data. The CBMP Terrestrial Plan intends to build upon and expand existing monitoring networks, engaging participants across a range of capacity and interests. The presentation will summarize the recommended focal soil ecosystem components...

  17. Dynamic belowground ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W. F.; Santantonio, D.; McGinty, D.

    1979-01-01

    Roots comprise the primary interface between plant and soil for uptake of water and nutrients. Much is known about the biochemistry, cell physiology and membrane physics associated with these important processes. In this paper we discuss the role of the belowground ecosystem, especially the autotrophic root component, in the structure and function of forest ecosystems. Beyond recognizing roles of anchoring terrestrial plants and uptake of water and nutrients, this component of the forest has been largely neglected in an ecosystem context. In order to focus discussion on the properties of the belowground ecosystem, we use the term rhizosphere to include roots, mycorrhizae, microbes, and rhizophagus invertebrates.

  18. Terrestrial magnetosphere

    International Nuclear Information System (INIS)

    Pande, D.C.; Agarwal, D.C.

    1982-01-01

    This paper presents a review about terrestrial magnetosphere. During the last few years considerable investigation have been carried out about the properties of Solar Wind and its interaction with planetary magnetic fields. It is therefore of high importance to accumulate all the investigations in a comprehensive form. The paper reviews the property of earth's magnetosphere, magnetosheath, magneto pause, polar cusps, bow shook and plasma sheath. (author)

  19. Equilibration of the terrestrial water, nitrogen, and carbon cycles

    OpenAIRE

    Schimel, David S.; Braswell, B. H.; Parton, W. J.

    1997-01-01

    Recent advances in biologically based ecosystem models of the coupled terrestrial, hydrological, carbon, and nutrient cycles have provided new perspectives on the terrestrial biosphere’s behavior globally, over a range of time scales. We used the terrestrial ecosystem model Century to examine relationships between carbon, nitrogen, and water dynamics. The model, run to a quasi-steady-state, shows strong correlations between carbon, water, and nitrogen fluxes that l...

  20. Potential increases in natural disturbance rates could offset forest management impacts on ecosystem carbon stocks.

    Science.gov (United States)

    John B. Bradford; Nicholas R. Jensen; Grant M. Domke; Anthony W. D' Amato

    2013-01-01

    Forested ecosystems contain the majority of the world’s terrestrial carbon, and forest management has implications for regional and global carbon cycling. Carbon stored in forests changes with stand age and is affected by natural disturbance and timber harvesting. We examined how harvesting and disturbance interact to influence forest carbon stocks over the Superior...

  1. Soil and terrestrial biology studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Soil and terrestrial biology studies focused on developing an understanding of the uptake of gaseous substances from the atmosphere by plants, biodegradation of oil, and the movement of Pu in the terrestrial ecosystems of the southeastern United States. Mathematical models were developed for SO 2 and tritium uptake from the atmosphere by plants; the uptake of tritium by soil microorganisms was measured; and the relationships among the Pu content of soil, plants, and animals of the Savannah River Plant area were studied. Preliminary results are reported for studies on the biodegradation of waste oil on soil surfaces

  2. Seasonality and Management Affect Land Surface Temperature Differences Between Loblolly Pine and Switchgrass Ecosystems in Central Virginia

    Science.gov (United States)

    Ahlswede, B.; Thomas, R. Q.; O'Halloran, T. L.; Rady, J.; LeMoine, J.

    2017-12-01

    Changes in land-use and land management can have biogeochemical and biophysical effects on local and global climate. While managed ecosystems provide known food and fiber benefits, their influence on climate is less well quantified. In the southeastern United States, there are numerous types of intensely managed ecosystems but pine plantations and switchgrass fields represent two biogeochemical and biophysical extremes; a tall, low albedo forest with trees harvested after multiple decades vs. a short, higher albedo C4 grass field that is harvested annually. Despite the wide spread use of these ecosystems for timber and bioenergy, a quantitative, empirical evaluation of the net influence of these ecosystems on climate is lacking because it requires measuring both the greenhouse gas and energy balance of the ecosystems while controlling for the background weather and soil environment. To address this need, we established a pair of eddy flux towers in these ecosystems that are co-located (1.5 km apart) in Central Virginia and measured the radiative energy, non-radiative energy and carbon fluxes, along with associated biometeorology variables; the paired site has run since April 2016. During the first 1.5 years (two growing seasons), we found strong seasonality in the difference in surface temperature between the two ecosystems. In the growing seasons, both sites had similar surface temperature despite higher net radiation in pine. Following harvest of the switchgrass in September, the switchgrass temperatures increased relative to pine. In the winter, the pine ecosystem was warmer. We evaluate the drivers of these intra-annual dynamics and compare the climate influence of these biophysical differences to the differences in carbon fluxes between the sites using a suite of established climate regulation services metrics. Overall, our results show tradeoffs exist between the biogeochemical and biophysical climate services in managed ecosystems in the southeastern United

  3. Sedimentology and depositional environments of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania: New insight into Cretaceous and Paleogene terrestrial ecosystems and tectonics in sub-equatorial Africa

    Science.gov (United States)

    Roberts, Eric M.; O'Connor, Patrick M.; Stevens, Nancy J.; Gottfried, Michael D.; Jinnah, Zubair A.; Ngasala, Sifael; Choh, Adeline M.; Armstrong, Richard A.

    2010-05-01

    The Red Sandstone Group (RSG) in the Rukwa Rift Basin of southwestern Tanzania represents one of the only well-exposed, fossiliferous Cretaceous-Paleogene continental sedimentary sequences in sub-equatorial Africa. The significance of the RSG for reconstructing the paleoenvironmental and paleoclimatic history of African ecosystems during these critical time periods has been obfuscated by long-standing confusion and debate over the age of the deposits. Detailed stratigraphic, sedimentologic, and paleontologic investigations of the RSG conducted between 2002 and 2008 have produced a wealth of new fossil discoveries and data on lithofacies, alluvial architecture, sedimentary provenance, clay mineralogy and geochronology that resolve the long-standing debate over the age of these deposits. This study confirms the existence of an extensive middle Cretaceous sequence, herein named the Galula Formation, and subdivided into the Mtuka and Namba members. Moreover, we document the existence of a previously unrecognized late Paleogene continental sequence termed the Nsungwe Formation, which is divided into the Utengule and Songwe members. The Galula Formation represents a 600-3000 m thick sequence of amalgamated, braided fluvial deposits that were deposited across a large braidplain system via multiple parallel channels that had their source in the highlands of Malawi and Zambia. The middle Cretaceous Dinosaur Beds of Malawi are hypothesized to be at least partially correlative with the Galula Formation, and represent proximal deposits of this large, northwest flowing, trunk stream system. A moderately diverse terrestrial vertebrate fauna, including multiple species of dinosaurs, crocodyliforms, turtles, fishes and mammals have been recovered, along with a sparse aquatic molluscan fauna. Lithofacies and clay mineralogy indicate that Cretaceous paleoclimate ameliorated during deposition of the Galula Formation, transitioning from tropical semi-arid to tropical humid conditions

  4. Conservación de la biodiversidad en Chile: Nuevos desafíos y oportunidades en ecosistemas terrestres y marinos costeros Biodiversity conservation in Chile: New challenges and opportunities in terrestrial and marine coastal ecosystems

    Directory of Open Access Journals (Sweden)

    CARMEN JORQUERA-JARAMILLO

    2012-09-01

    Full Text Available La pérdida de la biodiversidad producida por el crecimiento demográfico, la demanda por recursos y la actividad productiva es contradictoria con el reconocimiento de su importancia. En ecosistemas terrestres, el Sistema Nacional de Áreas Protegidas del Estado (SNASPE contiene cerca del 19 % del territorio de Chile continental; aunque no representa todos los ecosistemas con especies amenazadas, puede ser complementado implementando nuevas áreas protegidas públicas (AP y privadas (APP. El desarrollo de áreas marinas protegidas (AMP es incipiente, y algunas iniciativas comparten la responsabilidad de conservación con los usuarios locales. En Chile, un conjunto de reglamentos, normas legales y tratados internacionales promueven distintas oportunidades de conservación en ecosistemas terrestres y marinos costeros, de las cuales emergen nuevos desafíos. Entre estos destacan, estandarizar la clasificación de especies según categorías de conservación en un protocolo internacional y optimizar las metodologías para seleccionar áreas prioritarias, ambos criterios indispensables para decidir qué y dónde conservar. Otro desafío es integrar el valor intrínseco de la biodiversidad con los servicios ecosistémicos que presta para instaurar una cultura participativa. Esto mejoraría la efectividad de las distintas estrategias de protección y uso sustentable de la biodiversidad al incorporar la educación y la participación ciudadana desde una perspectiva biocultural. La educación fomenta la conservación de la naturaleza al hacernos conscientes de nuestro entorno; mientras que la participación involucra a los ciudadanos como un actor más en la toma de decisiones, procurando la aplicación efectiva de las estrategias de conservación de la biodiversidad.Biodiversity loss caused by population growth, the demand of resources and productive activities is inconsistent with the recognition of its importance. In terrestrial ecosystems, the

  5. Recording of ecological half-lives of {sup 90}Sr and {sup 137}Cs in terrestrial and aquatic ecosystems; Erfassung oekologischer Halbwertszeiten von {sup 90}Sr und {sup 137}Cs in terrestrischen und aquatischen Oekosystemen

    Energy Technology Data Exchange (ETDEWEB)

    Proehl, G.; Fiedler, I. [GSF-Forschungszentrum fuer Umwelt und Gesundheit, Neuherberg (Germany). Inst. fuer Strahlenschutz; Klemt, E.; Zibold, G. [Fachhochschule Ravensburg-Weingarten (Germany); Ehlken, S. [Universitaet Bremen (Germany). Fachbereich Physik

    2004-07-01

    Within this project, the long-term behaviour of {sup 90}Sr and {sup 137}Cs in foods, feeds and a variety of environmental was analysed. The long-term behaviour is quantified by means of the ecological half-life which integrates all processes that cause a decrease of activity in a given medium as leaching, fixation and erosion. The following results were achieved: - For plant and animal food products, the ecological half-lives are in the range of 4 to 6 and 10 to 20 years for cesium and strontium respectively. The ecological half-lives for the period 1965 to 1985 are slightly shorter than those derived from monitoring measurements performed after 1987, due to the ongoing deposition in the post weapons' fallout period. - According to the German radioecological model that is applied during licensing of nuclear installations to assess radiation exposures to the general due to planned releases, the ecological half-lives for plant food products are 26 and 13 a for cesium and strontium respectively. In radioecological model that is used within the decision support system RODOS, the ecological half-lives are 8 years for Cesium and 14 years for strontium, which agrees well with the finding of this study. - For roe deer, deer, wild boar and forest plants (including mushrooms), under Middle European conditions, the ecological half-lives are about 12 years for cesium. However, in Ukraine, the cesium levels in forest products are much more persistent; in some cases the decrease of activity is only caused by the radioactive decay. - The variability of the long-term behaviour of 137Cs and 90Sr in freshwater ecosystems is much more pronounced than for terrestrial systems. It depends strongly on the sitespecific characteristics. The observed ecological half-lives for 137Cs and 90Sr cover a wide range from several days to several years. - The data to derive ecological half-lives of cesium in soil is relatively poor. For the upper soil layer of 0-10 cm, ecological half

  6. Environmental risk assessment for invasive alien species : A case study of apple snails affecting ecosystem services in Europe

    NARCIS (Netherlands)

    Gilioli, Gianni; Schrader, Gritta; Carlsson, Nils; van Donk, Ellen; van Leeuwen, Casper H.A.; Martín, Pablo R.; Pasquali, Sara; Vilà, Montserrat; Vos, Sybren

    2017-01-01

    The assessment of the risk posed by invasive alien species (IAS) to the environment is a component of increasing importance for Pest Risk Analysis. Standardized and comprehensive procedures to assess their impacts on ecosystem services have been developed only recently. The invasive apple snails

  7. Environmental risk assessment for invasive alien species: A case study of apple snails affecting ecosystem services in Europe

    NARCIS (Netherlands)

    Gilioli, Gianni; Schrader, Gritta; Carlsson, Nils; van Donk, Ellen; van Leeuwen, Casper H.A.; Martín, Pablo R.; Pasquali, Sara; Vilà, Montserrat; Vos, Sybren

    Abstract The assessment of the risk posed by invasive alien species (IAS) to the environment is a component of increasing importance for Pest Risk Analysis. Standardized and comprehensive procedures to assess their impacts on ecosystem services have been developed only recently. The invasive apple

  8. Terrestrial biogeochemical cycles - Global interactions with the atmosphere and hydrology

    Science.gov (United States)

    Schimel, David S.; Parton, William J.; Kittel, Timothy G. F.

    1991-01-01

    A review is presented of developments in ecosystem theory, remote sensing, and geographic information systems that support new endeavors in spatial modeling. A paradigm has emerged to predict ecosystem behavior based on understanding responses to multiple resources. Ecosystem models couple primary production to decomposition and nutrient availability utilizing this paradigm. It is indicated that coupling of transport and ecosystem processes alters the behavior of earth system components (terrestrial ecosystems, hydrology, and the atmosphere) from that of an uncoupled model.

  9. Future directions of ecosystem science

    Science.gov (United States)

    Baron, Jill S.; Galvin, Kathleen A.

    1990-01-01

    Scientific knowledge about ecosystem structure and function has expanded greatly during the past few decades. Terrestrial and aquatic nutrient cycling, ecosystem energetics, population dynamics, belowground processes, and food webs have been studied at the plot, stand, watershed, and landscape levels at many locations around the globe. Ideas about terrestrial-atmospheric interactions and human interference in these processes have changed dramatically. There is new appreciation of the need to incorporate into ecosystem studies the interactions between human populations and the ecosystem, not only because humans affect ecosystem processes, but because these systems support human populations (Glantz 1988, Holden 1988, Parry et al. 1988, WCED 1987). Recent advances in ecosystem science are due, in part, to technological improvements in computing power, new laboratory and field physical and chemical analytical techniques, and satellite imagery for remote sensing of Earth's structure and dynamics. Modeling and geographic information systems have provided the capability for integrating multiple data sets with process simulations to generate hypotheses about regional ecosystem function. Concurrent with these scientific developments has been a growing concern about the links between the health of the environment and world-wide industrial, land, and resource-management practices. Environmental damage at the local level was widely recognized in the 1960s, prompting the environmental movement of that decade. Regional environmental problems with multiple effects and politically difficult solutions have been perceived more recently; the issue of acidic deposition provides an example of such a second-generation concern (Clark and Holling 1985). Today there is a growing awareness of global-scale environmental degradation brought about by the combined actions of all peoples on Earth (Clark 1989, Woodmansee et al. 1988). The three levels of environmental concern--local, regional

  10. Measuring feeding traits of a range of litter-consuming terrestrial snails : Leaf litter consumption, faeces production and scaling with body size

    NARCIS (Netherlands)

    Astor, Tina; Lenoir, Lisette; Berg, Matty P.