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Sample records for rapid ecosystem change

  1. Complex interactions in Lake Michigan’s rapidly changing ecosystem

    USGS Publications Warehouse

    Vanderploeg, Henry A.; Bunnell, David B.; Carrick, Hunter J.; Hook, Tomas O.

    2015-01-01

    For over 30 years, Lake Michigan’s food web has been in a constant state of transition from reductions in nutrient loading and proliferation of invasive species at multiple trophic levels. In particular, there has been concern about impacts from the invasive predatory cercopagids (Bythotrephes longimanus and Cercopagis pengoi) and expanding dreissenid mussel and round goby populations. This special issue brings together papers that explore the status of the Lake Michigan food web and the factors responsible for these changes, and suggests research paths that must be taken for understanding and predicting system behavior. This introductory paper describes the special issue origin, presents an overview of the papers, and draws overarching conclusions from the papers.

  2. Rapid ecosystem change challenges the adaptive capacity of Local Environmental Knowledge

    PubMed Central

    Fernández-Llamazares, Álvaro; Díaz-Reviriego, Isabel; Luz, Ana C.; Cabeza, Mar; Pyhälä, Aili; Reyes-García, Victoria

    2015-01-01

    The use of Local Environmental Knowledge has been considered as an important strategy for adaptive management in the face of Global Environmental Change. However, the unprecedented rates at which global change occurs may pose a challenge to the adaptive capacity of local knowledge systems. In this paper, we use the concept of the shifting baseline syndrome to examine the limits in the adaptive capacity of the local knowledge of an indigenous society facing rapid ecosystem change. We conducted semi-structured interviews regarding perceptions of change in wildlife populations and in intergenerational transmission of knowledge amongst the Tsimane’, a group of hunter-gatherers of Bolivian Amazonia (n = 300 adults in 13 villages). We found that the natural baseline against which the Tsimane’ measure ecosystem changes might be shifting with every generation as a result of (a) age-related differences in the perception of change and (b) a decrease in the intergenerational sharing of environmental knowledge. Such findings suggest that local knowledge systems might not change at a rate quick enough to adapt to conditions of rapid ecosystem change, hence potentially compromising the adaptive success of the entire social-ecological system. With the current pace of Global Environmental Change, widening the gap between the temporal rates of on-going ecosystem change and the timescale needed for local knowledge systems to adjust to change, efforts to tackle the shifting baseline syndrome are urgent and critical for those who aim to use Local Environmental Knowledge as a tool for adaptive management. PMID:26097291

  3. Recent Rapid Climate Changes in Antarctic and Their Influence on Low Diversity Ecosystems

    NASA Astrophysics Data System (ADS)

    Chwedorzewska, Katarzyna

    2010-01-01

    The geographic position, astronomic factors (e.g. the Earth's maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation. Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems.

  4. Recent Rapid Climate Changes in Antarctic and their Influence on Low Diversity Ecosystems

    NASA Astrophysics Data System (ADS)

    Chwedorzewska, Katarzyna J.

    2010-01-01

    The geographic position, astronomic factors (e.g. the Earth's maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation. Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems

  5. Whole-ecosystem study shows rapid fish-mercury response to changes in mercury deposition

    USGS Publications Warehouse

    Harris, R.C.; Rudd, J.W.M.; Amyot, M.; Babiarz, C.L.; Beaty, K.G.; Blanchfield, P.J.; Bodaly, R.A.; Branfireun, B.A.; Gilmour, C.C.; Graydon, J.A.; Heyes, A.; Hintelmann, H.; Hurley, J.P.; Kelly, C.A.; Krabbenhoft, D.P.; Lindberg, S.E.; Mason, R.P.; Paterson, M.J.; Podemski, C.L.; Robinson, A.; Sandilands, K.A.; Southworthn, G.R.; St. Louis, V.L.; Tate, M.T.

    2007-01-01

    Methylmercury contamination of fisheries from centuries of industrial atmospheric emissions negatively impacts humans and wild-life worldwide. The response of fish methylmercury concentrations to changes in mercury deposition has been difficult to establish because sediments/soils contain large pools of historical contamination, and many factors in addition to deposition affect fish mercury. To test directly the response of fish contamination to changing mercury deposition, we conducted a whole-ecosystem experiment, increasing the mercury load to a lake and its watershed by the addition of enriched stable mercury isotopes. The isotopes allowed us to distinguish between experimentally applied mercury and mercury already present in the ecosystem and to examine bioaccumulation of mercury deposited to different parts of the watershed. Fish methylmercury concentrations responded rapidly to changes in mercury deposition over the first 3 years of study. Essentially all of the increase in fish methylmercury concentrations came from mercury deposited directly to the lake surface. In contrast, <1% of the mercury isotope deposited to the watershed was exported to the lake. Steady state was not reached within 3 years. Lake mercury isotope concentrations were still rising in lake biota, and watershed mercury isotope exports to the lake were increasing slowly. Therefore, we predict that mercury emissions reductions will yield rapid (years) reductions in fish methylmercury concentrations and will yield concomitant reductions in risk. However, a full response will be delayed by the gradual export of mercury stored in watersheds. The rate of response will vary among lakes depending on the relative surface areas of water and watershed. ?? 2007 by The National Academy of Sciences of the USA.

  6. Net Ecosystem Exchange of CO2 with Rapidly Changing High Arctic Landscapes

    NASA Astrophysics Data System (ADS)

    Emmerton, C. A.

    2015-12-01

    High Arctic landscapes are expansive and changing rapidly. However our understanding of their functional responses and potential to mitigate or enhance anthropogenic climate change is limited by few measurements. We collected eddy covariance measurements to quantify the net ecosystem exchange (NEE) of CO2 with polar semidesert and meadow wetland landscapes at the highest-latitude location measured to date (82°N). We coupled these rare data with ground and satellite vegetation production measurements (Normalized Difference Vegetation Index; NDVI) to evaluate the effectiveness of upscaling local to regional NEE. During the growing season, the dry polar semidesert landscape was a near zero sink of atmospheric CO2 (NEE: -0.3±13.5 g C m-2). A nearby meadow wetland accumulated over two magnitudes more carbon (NEE: -79.3±20.0 g C m-2) than the polar semidesert landscape, and was similar to meadow wetland NEE at much more southern latitudes. Polar semidesert NEE was most influenced by moisture, with wetter surface soils resulting in greater soil respiration and CO2 emissions. At the meadow wetland, soil heating enhanced plant growth, which in turn increased CO2 uptake. Our upscaling assessment found that polar semidesert NDVI measured on site was low (mean: 0.120-0.157) and similar to satellite measurements (mean: 0.155-0.163). However, weak plant growth resulted in poor satellite NDVI-NEE relationships and created challenges for remotely-detecting changes in the cycling of carbon on the polar semidesert landscape. The meadow wetland appeared more suitable to assess plant production and NEE via remote-sensing, however high Arctic wetland extent is constrained by topography to small areas that may be difficult to resolve with large satellite pixels. We predict that until summer precipitation and humidity increases substantially, climate-related changes of dry high Arctic landscapes may be restricted by poor soil moisture retention, and therefore have some inertia against

  7. Net ecosystem exchange of CO2 with rapidly changing high Arctic landscapes.

    PubMed

    Emmerton, Craig A; St Louis, Vincent L; Humphreys, Elyn R; Gamon, John A; Barker, Joel D; Pastorello, Gilberto Z

    2016-03-01

    High Arctic landscapes are expansive and changing rapidly. However, our understanding of their functional responses and potential to mitigate or enhance anthropogenic climate change is limited by few measurements. We collected eddy covariance measurements to quantify the net ecosystem exchange (NEE) of CO2 with polar semidesert and meadow wetland landscapes at the highest latitude location measured to date (82°N). We coupled these rare data with ground and satellite vegetation production measurements (Normalized Difference Vegetation Index; NDVI) to evaluate the effectiveness of upscaling local to regional NEE. During the growing season, the dry polar semidesert landscape was a near-zero sink of atmospheric CO2 (NEE: -0.3 ± 13.5 g C m(-2) ). A nearby meadow wetland accumulated over 300 times more carbon (NEE: -79.3 ± 20.0 g C m(-2) ) than the polar semidesert landscape, and was similar to meadow wetland NEE at much more southerly latitudes. Polar semidesert NEE was most influenced by moisture, with wetter surface soils resulting in greater soil respiration and CO2 emissions. At the meadow wetland, soil heating enhanced plant growth, which in turn increased CO2 uptake. Our upscaling assessment found that polar semidesert NDVI measured on-site was low (mean: 0.120-0.157) and similar to satellite measurements (mean: 0.155-0.163). However, weak plant growth resulted in poor satellite NDVI-NEE relationships and created challenges for remotely detecting changes in the cycling of carbon on the polar semidesert landscape. The meadow wetland appeared more suitable to assess plant production and NEE via remote sensing; however, high Arctic wetland extent is constrained by topography to small areas that may be difficult to resolve with large satellite pixels. We predict that until summer precipitation and humidity increases enough to offset poor soil moisture retention, climate-related changes to productivity on polar semideserts may be restricted. PMID:26279166

  8. An unusually large phytoplankton spring bloom drives rapid changes in benthic diversity and ecosystem function

    NASA Astrophysics Data System (ADS)

    Zhang, Qingtian; Warwick, Richard M.; McNeill, Caroline L.; Widdicombe, Claire E.; Sheehan, Aaron; Widdicombe, Stephen

    2015-09-01

    In 2012, the Western English Channel experienced an unusually large and long-lived phytoplankton spring bloom. When compared with data from the past 20 years, average phytoplankton biomass at Station L4 (part of the Western Channel Observatory) was approximately 3× greater and lasted 50% longer than any previous year. Regular (mostly weekly) box core samples were collected from this site before, during and after the bloom to determine its impact on macrofaunal abundance, diversity, biomass, community structure and function. The spring bloom of 2012 was shown to support a large and rapid response in the majority of benthic taxa and functional groups. However, key differences in the precise nature of this response, as well as in its timing, was observed between different macrofauna feeding groups. Deposit feeders responded almost instantly at the start of the bloom, primarily thorough an increase in abundance. Suspension feeders and opportunistic/predatory/carnivorous taxa responded slightly more slowly and primarily with an increase in biomass. At the end of the bloom a rapid decline in macrobenthic abundance, diversity and biomass closely followed the decline in phytoplankton biomass. With suspension feeders showing evidence of this decline a few weeks before deposit feeders, it was concluded that this collapse in benthic communities was driven primarily by food availability and competition. However, it is possible that environmental hypoxia and the presence of toxic benthic cyanobacteria could also have contributed to this decline. This study shows evidence for strong benthic-pelagic coupling at L4; a shallow (50 m), coastal, fine-sand habitat. It also demonstrates that in such habitats, it is not just planktonic organisms that demonstrate clear community phenology. Different functional groups within the benthic assemblage will respond to the spring bloom in specific manner, with implications for key ecosystem functions and processes, such as secondary production

  9. Rapid Morphological Change in the Masticatory Structures of an Important Ecosystem Service Provider

    PubMed Central

    Doudna, John W.; Danielson, Brent J.

    2015-01-01

    Humans have altered the biotic and abiotic environmental conditions of most organisms. In some cases, such as intensive agriculture, an organism’s entire ecosystem is converted to novel conditions. Thus, it is striking that some species continue to thrive under such conditions. The prairie deer mouse (Peromyscus maniculatus bairdii) is an example of such an organism, and so we sought to understand what role evolutionary adaptation played in the success of this species, with particular interest in adaptations to novel foods. In order to understand the evolutionary history of this species’ masticatory structures, we examined the maxilla, zygomatic plate, and mandible of historic specimens collected prior to 1910 to specimens collected in 2012 and 2013. We found that mandibles, zygomatic plates, and maxilla have all changed significantly since 1910, and that morphological development has shifted significantly. We present compelling evidence that these differences are due to natural selection as a response to a novel and ubiquitous food source, waste grain (corn, Zea mays and soybean, Glycine max). PMID:26061880

  10. Rapid Morphological Change in the Masticatory Structures of an Important Ecosystem Service Provider.

    PubMed

    Doudna, John W; Danielson, Brent J

    2015-01-01

    Humans have altered the biotic and abiotic environmental conditions of most organisms. In some cases, such as intensive agriculture, an organism's entire ecosystem is converted to novel conditions. Thus, it is striking that some species continue to thrive under such conditions. The prairie deer mouse (Peromyscus maniculatus bairdii) is an example of such an organism, and so we sought to understand what role evolutionary adaptation played in the success of this species, with particular interest in adaptations to novel foods. In order to understand the evolutionary history of this species' masticatory structures, we examined the maxilla, zygomatic plate, and mandible of historic specimens collected prior to 1910 to specimens collected in 2012 and 2013. We found that mandibles, zygomatic plates, and maxilla have all changed significantly since 1910, and that morphological development has shifted significantly. We present compelling evidence that these differences are due to natural selection as a response to a novel and ubiquitous food source, waste grain (corn, Zea mays and soybean, Glycine max). PMID:26061880

  11. Rapid Ecological Change in Two Contrasting Lake Ecosystems: Evidence of Threshold Responses, Altered Species Dynamics, and Perturbed Patterns of Variability

    NASA Astrophysics Data System (ADS)

    Simpson, G. L.

    2015-12-01

    Studying threshold responses to environmental change is often made difficult due to the paucity of monitoring data prior to and during change. Progress has been made via theoretical models of regime shifts or experimental manipulation but natural, real world, examples of threshold change are limited and in many cases inconclusive. Lake sediments provide the potential to examine abrupt ecological change by directly observing how species, communities, and biogeochemical proxies responded to environmental perturbation or recorded ecosystem change. These records are not problem-free; age uncertainties, uneven and variable temporal resolution, and time-consuming taxonomic work all act to limit the scope and scale of the data or complicate its analysis. Here I use two annually laminated records 1. Kassjön, a seasonally anoxic mesotrophic lake in N Sweden, and2. Baldeggersee, a nutrient rich, hardwater lake on the central Swiss Plateau to investigate lake ecosystem responses to abrupt environmental change using ideal paleoecological time series. Rapid cooling 2.2kyr ago in northern Sweden significantly perturbed the diatom community of Kassjön. Using wavelet analysis, this amelioration in climate also fundamentally altered patterns of variance in diatom abundances, suppressing cyclicity in species composition that required several hundred years to reestablish. Multivariate wavelet analysis of the record showed marked switching between synchronous and asynchronous species dynamics in response to rapid climatic cooling and subsequent warming. Baldeggersee has experienced a long history of eutrophication and the diatom record has been used as a classic illustration of a regime shift in response to nutrient loading. Time series analysis of the record identified some evidence of a threshold-like response in the diatoms. A stochastic volatility model identified increasing variance in composition prior to the threshold, as predicted from theory, and a switch from compensatory

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  13. Benefits and costs of ecological restoration: Rapid assessment of changing ecosystem service values at a U.K. wetland

    PubMed Central

    Peh, Kelvin S-H; Balmford, Andrew; Field, Rob H; Lamb, Anthony; Birch, Jennifer C; Bradbury, Richard B; Brown, Claire; Butchart, Stuart H M; Lester, Martin; Morrison, Ross; Sedgwick, Isabel; Soans, Chris; Stattersfield, Alison J; Stroh, Peter A; Swetnam, Ruth D; Thomas, David H L; Walpole, Matt; Warrington, Stuart; Hughes, Francine M R

    2014-01-01

    Restoration of degraded land is recognized by the international community as an important way of enhancing both biodiversity and ecosystem services, but more information is needed about its costs and benefits. In Cambridgeshire, U.K., a long-term initiative to convert drained, intensively farmed arable land to a wetland habitat mosaic is driven by a desire both to prevent biodiversity loss from the nationally important Wicken Fen National Nature Reserve (Wicken Fen NNR) and to increase the provision of ecosystem services. We evaluated the changes in ecosystem service delivery resulting from this land conversion, using a new Toolkit for Ecosystem Service Site-based Assessment (TESSA) to estimate biophysical and monetary values of ecosystem services provided by the restored wetland mosaic compared with the former arable land. Overall results suggest that restoration is associated with a net gain to society as a whole of $199 ha−1y−1, for a one-off investment in restoration of $2320 ha−1. Restoration has led to an estimated loss of arable production of $2040 ha−1y−1, but estimated gains of $671 ha−1y−1 in nature-based recreation, $120 ha−1y−1 from grazing, $48 ha−1y−1 from flood protection, and a reduction in greenhouse gas (GHG) emissions worth an estimated $72 ha−1y−1. Management costs have also declined by an estimated $1325 ha−1y−1. Despite uncertainties associated with all measured values and the conservative assumptions used, we conclude that there was a substantial gain to society as a whole from this land-use conversion. The beneficiaries also changed from local arable farmers under arable production to graziers, countryside users from towns and villages, and the global community, under restoration. We emphasize that the values reported here are not necessarily transferable to other sites. PMID:25505517

  14. Benefits and costs of ecological restoration: Rapid assessment of changing ecosystem service values at a U.K. wetland.

    PubMed

    Peh, Kelvin S-H; Balmford, Andrew; Field, Rob H; Lamb, Anthony; Birch, Jennifer C; Bradbury, Richard B; Brown, Claire; Butchart, Stuart H M; Lester, Martin; Morrison, Ross; Sedgwick, Isabel; Soans, Chris; Stattersfield, Alison J; Stroh, Peter A; Swetnam, Ruth D; Thomas, David H L; Walpole, Matt; Warrington, Stuart; Hughes, Francine M R

    2014-10-01

    Restoration of degraded land is recognized by the international community as an important way of enhancing both biodiversity and ecosystem services, but more information is needed about its costs and benefits. In Cambridgeshire, U.K., a long-term initiative to convert drained, intensively farmed arable land to a wetland habitat mosaic is driven by a desire both to prevent biodiversity loss from the nationally important Wicken Fen National Nature Reserve (Wicken Fen NNR) and to increase the provision of ecosystem services. We evaluated the changes in ecosystem service delivery resulting from this land conversion, using a new Toolkit for Ecosystem Service Site-based Assessment (TESSA) to estimate biophysical and monetary values of ecosystem services provided by the restored wetland mosaic compared with the former arable land. Overall results suggest that restoration is associated with a net gain to society as a whole of $199 ha(-1)y(-1), for a one-off investment in restoration of $2320 ha(-1). Restoration has led to an estimated loss of arable production of $2040 ha(-1)y(-1), but estimated gains of $671 ha(-1)y(-1) in nature-based recreation, $120 ha(-1)y(-1) from grazing, $48 ha(-1)y(-1) from flood protection, and a reduction in greenhouse gas (GHG) emissions worth an estimated $72 ha(-1)y(-1). Management costs have also declined by an estimated $1325 ha(-1)y(-1). Despite uncertainties associated with all measured values and the conservative assumptions used, we conclude that there was a substantial gain to society as a whole from this land-use conversion. The beneficiaries also changed from local arable farmers under arable production to graziers, countryside users from towns and villages, and the global community, under restoration. We emphasize that the values reported here are not necessarily transferable to other sites. PMID:25505517

  15. Terrestrial ecosystems and climatic change

    SciTech Connect

    Emanuel, W.R. ); Schimel, D.S. . Natural Resources Ecology Lab.)

    1990-01-01

    The structure and function of terrestrial ecosystems depend on climate, and in turn, ecosystems influence atmospheric composition and climate. A comprehensive, global model of terrestrial ecosystem dynamics is needed. A hierarchical approach appears advisable given currently available concepts, data, and formalisms. The organization of models can be based on the temporal scales involved. A rapidly responding model describes the processes associated with photosynthesis, including carbon, moisture, and heat exchange with the atmosphere. An intermediate model handles subannual variations that are closely associated with allocation and seasonal changes in productivity and decomposition. A slow response model describes plant growth and succession with associated element cycling over decades and centuries. These three levels of terrestrial models are linked through common specifications of environmental conditions and constrain each other. 58 refs.

  16. COSMOS Sensors in Agricultural Ecosystems: Accounting for Rapid Changes in Biomass in Order to Monitor Root Zone Water

    NASA Astrophysics Data System (ADS)

    Hornbuckle, B. K.; Irvin, S.; Franz, T. E.

    2013-12-01

    Cosmic rays from outer space produce neutrons in the atmosphere which are scattered and absorbed by hydrogen in the atmosphere, soil, and vegetation. The intensity of neutrons just above Earth's surface is inversely related to the hydrogen (and therefore water content) of the soil. Neutron detectors situated 2 m above the ground are sensitive to the soil water content of the top 30 cm. Daily estimates of soil water with an uncertainty of < 1% are possible. An individual neutron detector observes an area nearly 700 m in diameter. This spatial scale closely matches the scale of agricultural fields in the Midwest United States. We claim that future weather and climate models will need to resolve soil moisture at this field scale in order to best represent land-atmosphere interactions and subsequently improve forecasts of the soil moisture reservoir in this region. Using neutron detectors to observe soil moisture circumvents the problem of 'scaling up' point observations of soil moisture made with in-situ sensors like TDR or simple gravimetric sampling. The COSMOS (COsmic-ray Soil Moisture Observing System) is a network of nearly 60 neutron detectors deployed in a variety of ecosystems across the United States. Each detector is connected to the network through a satellite communication link and data is available in real-time via the web. The goal of the network is to eventually deploy 500 detectors and provide continental-scale observations of plant-available water. Recently it has been recognized that all hydrogen sources must be considered when interpreting neutron measurements. These sources include static pools of hydrogen (soil chemical composition, bound soil water, and soil organic matter), quasi-static pools (the water stored in vegetation, as well as vegetation dry matter), and transient pools (soil pore water, water vapor in the atmosphere, ponded water, snow, and possibly dew and intercepted precipitation). In the agricultural ecosystems of the Midwest, both

  17. Changing Ecosystem Service Values Following Technological Change

    NASA Astrophysics Data System (ADS)

    Honey-Rosés, Jordi; Schneider, Daniel W.; Brozović, Nicholas

    2014-06-01

    Research on ecosystem services has focused mostly on natural areas or remote places, with less attention given to urban ecosystem services and their relationship with technological change. However, recent work by urban ecologists and urban designers has more closely examined and appreciated the opportunities associated with integrating natural and built infrastructures. Nevertheless, a perception remains in the literature on ecosystem services that technology may easily and irreversibly substitute for services previously obtained from ecosystems, especially when the superiority of the engineered system motivated replacement in the first place. We emphasize that the expected tradeoff between natural and manufactured capital is false. Rather, as argued in other contexts, the adoption of new technologies is complementary to ecosystem management. The complementarity of ecosystem services and technology is illustrated with a case study in Barcelona, Spain where the installation of sophisticated water treatment technology increased the value of the ecosystem services found there. Interestingly, the complementarity between natural and built infrastructures may remain even for the very ecosystems that are affected by the technological change. This finding suggests that we can expect the value of ecosystem services to co-evolve with new technologies. Technological innovation can generate new opportunities to harness value from ecosystems, and the engineered structures found in cities may generate more reliance on ecosystem processes, not less.

  18. Response of Earth's Ecosystem to Global Change

    NASA Technical Reports Server (NTRS)

    Peterson, David L.

    1996-01-01

    The Earth is in the midst of rapid and unprecedented change, much of it caused by the enormous reproductive and resource acquisition success of the human population. For the first time in Earth's history, the actions of one species-humans-are altering the atmospheric, climatic, biospheric, and edaphic processes on a scale that rivals natural processes. How will ecosystems, involving those manipulated and managed by humans largely for human use, respond to these changes? Clearly ecosystems have been adjusting to change throughout Earth's history and evolving in ways to adapt and to maintain self-organizing behavior. And in this process, the metabolic activity of the biosphere has altered the environmental conditions it experiences. I am going to confine this presentation to a few thoughts on the present state of terrestrial ecosystems and the urgency that changes in it is bringing to all of us.

  19. Rapid climate change

    SciTech Connect

    Morantine, M.C.

    1995-12-31

    Interactions between insolation changes due to orbital parameter variations, carbon dioxide concentration variations, the rate of deep water formation in the North Atlantic and the evolution of the northern hemisphere ice sheets during the most recent glacial cycle will be investigated. In order to investigate this period, a climate model is being developed to evaluate the physical mechanisms thought to be most significant during this period. The description of the model sub-components will be presented. The more one knows about the interactions between the sub-components of the climate system during periods of documented rapid climate change, the better equipped one will be to make rational decisions on issues related to impacts on the environment. This will be an effort to gauge the feedback processes thought to be instrumental in rapid climate shifts documented in the past, and their potential to influence the current climate. 53 refs.

  20. Rapid adaptation to climate change.

    PubMed

    Hancock, Angela M

    2016-08-01

    In recent years, amid growing concerns that changing climate is affecting species distributions and ecosystems, predicting responses to rapid environmental change has become a major goal. In this issue, Franks and colleagues take a first step towards this objective (Franks et al. 2016). They examine genomewide signatures of selection in populations of Brassica rapa after a severe multiyear drought. Together with other authors, Franks had previously shown that flowering time was reduced after this particular drought and that the reduction was genetically encoded. Now, the authors have sequenced previously stored samples to compare allele frequencies before and after the drought and identify the loci with the most extreme shifts in frequencies. The loci they identify largely differ between populations, suggesting that different genetic variants may be responsible for reduction in flowering time in the two populations. PMID:27463237

  1. Increased sensitivity to climate change in disturbed ecosystems.

    PubMed

    Kröel-Dulay, György; Ransijn, Johannes; Schmidt, Inger Kappel; Beier, Claus; De Angelis, Paolo; de Dato, Giovanbattista; Dukes, Jeffrey S; Emmett, Bridget; Estiarte, Marc; Garadnai, János; Kongstad, Jane; Kovács-Láng, Edit; Larsen, Klaus Steenberg; Liberati, Dario; Ogaya, Romà; Riis-Nielsen, Torben; Smith, Andrew R; Sowerby, Alwyn; Tietema, Albert; Penuelas, Josep

    2015-01-01

    Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports this relationship for the perturbation of climate change. Here we show that vegetation (abundance, species richness and species composition) across seven European shrublands is quite resistant to moderate experimental warming and drought, and responsiveness is associated with the dynamic state of the ecosystem, with recently disturbed sites responding to treatments. Furthermore, most of these responses are not rapid (2-5 years) but emerge over a longer term (7-14 years). These results suggest that successional state influences the sensitivity of ecosystems to climate change, and that ecosystems recovering from disturbances may be sensitive to even modest climatic changes. A research bias towards undisturbed ecosystems might thus lead to an underestimation of the impacts of climate change. PMID:25801187

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

    USGS Publications Warehouse

    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.

  3. Changing Arctic ecosystems: ecology of loons in a changing Arctic

    USGS Publications Warehouse

    Uher-Koch, Brian; Schmutz, Joel; Whalen, Mary; Pearce, John M.

    2014-01-01

    The U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative informs key resource management decisions for Arctic Alaska by providing scientific information on current and future ecosystem response to a changing climate. From 2010 to 2014, a key study area for the USGS CAE initiative has been the Arctic Coastal Plain of northern Alaska. This region has experienced rapid warming during the past 30 years, leading to the thawing of permafrost and changes to lake and river systems. These changes, and projections of continued change, have raised questions about effects on wildlife populations that rely on northern lake ecosystems, such as loons. Loons rely on freshwater lakes for nesting habitat and the fish and invertebrates inhabiting the lakes for food. Loons live within the National Petroleum Reserve-Alaska (NPR-A) on Alaska’s northern coast, where oil and gas development is expected to increase. Research by the USGS examines how breeding loons use the Arctic lake ecosystem and the capacity of loons to adapt to future landscape change.

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

    SciTech Connect

    Wike, L

    2005-06-01

    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 conditions. Also, as

  5. Sensitivity and Thresholds of Ecosystems to Abrupt Climate Change

    NASA Astrophysics Data System (ADS)

    Peteet, D. M.; Peteet, D. M.

    2001-12-01

    Rapid vegetational change is a hallmark of past abrupt climate change, as evidenced from Younger Dryas records in Europe, eastern North America, and the Pacific North American rim. The potential response of future ecosystems to abrupt climate change is targeted, with a focus on particular changes in the hydrological cycle. The vulnerability of ecosystems is notable when particular shifts cross thresholds of precipitation and temperature, as many plants and animals are adapted to specific climatic "windows". Significant forest species compositional changes occur at ecotonal boundaries, which are often the first locations to record a climatic response. Historical forest declines have been linked to stress, and even Pleistocene extinctions have been associated with human interaction at times of rapid climatic shifts. Environmental extremes are risky for reproductive stages, and result in nonlinearities. The role of humans in association with abrupt climate change suggests that many ecosystems may cross thresholds from which they will find it difficult to recover. Sectors particularly vulnerable will be reviewed.

  6. Rapid Change and Legitimacy

    ERIC Educational Resources Information Center

    Waldman, Matthew

    2010-01-01

    The exit and entry of executive leadership presents a powerful moment. In the exit of leadership, an institution must reflect on both successes and failures. With a contentious exit, as was the case of John Bowen at Nelson College, which is presented in this chapter, the organization needs to understand what precipitated the call for change and…

  7. Committed terrestrial ecosystem changes due to climate change

    NASA Astrophysics Data System (ADS)

    Jones, Chris; Lowe, Jason; Liddicoat, Spencer; Betts, Richard

    2009-07-01

    Targets for stabilizing climate change are often based on considerations of the impacts of different levels of global warming, usually assessing the time of reaching a particular level of warming. However, some aspects of the Earth system, such as global mean temperatures and sea level rise due to thermal expansion or the melting of large ice sheets, continue to respond long after the stabilization of radiative forcing. Here we use a coupled climate-vegetation model to show that in turn the terrestrial biosphere shows significant inertia in its response to climate change. We demonstrate that the global terrestrial biosphere can continue to change for decades after climate stabilization. We suggest that ecosystems can be committed to long-term change long before any response is observable: for example, we find that the risk of significant loss of forest cover in Amazonia rises rapidly for a global mean temperature rise above 2∘C. We conclude that such committed ecosystem changes must be considered in the definition of dangerous climate change, and subsequent policy development to avoid it.

  8. Extinction order and altered community structure rapidly disrupt ecosystem functioning.

    PubMed

    Larsen, Trond H; Williams, Neal M; Kremen, Claire

    2005-05-01

    By causing extinctions and altering community structure, anthropogenic disturbances can disrupt processes that maintain ecosystem integrity. However, the relationship between community structure and ecosystem functioning in natural systems is poorly understood. Here we show that habitat loss appeared to disrupt ecosystem functioning by affecting extinction order, species richness and abundance. We studied pollination by bees in a mosaic of agricultural and natural habitats in California and dung burial by dung beetles on recently created islands in Venezuela. We found that large-bodied bee and beetle species tended to be both most extinction-prone and most functionally efficient, contributing to rapid functional loss. Simulations confirmed that extinction order led to greater disruption of function than predicted by random species loss. Total abundance declined with richness and also appeared to contribute to loss of function. We demonstrate conceptually and empirically how the non-random response of communities to disturbance can have unexpectedly large functional consequences. PMID:21352458

  9. Impacts of Climate Change on Ecosystem Services

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecosystems, and the biodiversity and services they support, are intrinsically dependent on climate. During the twentieth century, climate change has had documented impacts on ecological systems, and impacts are expected to increase as climate change continues and perhaps even accelerates. This techn...

  10. When vegetation change alters ecosystem water availability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The combined effects of vegetation and climate change on biosphere-atmosphere water vapor (H2O) and carbon dioxide (CO2) exchanges are expected to vary depending, in part, on how biotic activity is controlled by and alters water availability. This is particularly important when a change in ecosystem...

  11. Marine ecosystem responses to Cenozoic global change.

    PubMed

    Norris, R D; Turner, S Kirtland; Hull, P M; Ridgwell, A

    2013-08-01

    The future impacts of anthropogenic global change on marine ecosystems are highly uncertain, but insights can be gained from past intervals of high atmospheric carbon dioxide partial pressure. The long-term geological record reveals an early Cenozoic warm climate that supported smaller polar ecosystems, few coral-algal reefs, expanded shallow-water platforms, longer food chains with less energy for top predators, and a less oxygenated ocean than today. The closest analogs for our likely future are climate transients, 10,000 to 200,000 years in duration, that occurred during the long early Cenozoic interval of elevated warmth. Although the future ocean will begin to resemble the past greenhouse world, it will retain elements of the present "icehouse" world long into the future. Changing temperatures and ocean acidification, together with rising sea level and shifts in ocean productivity, will keep marine ecosystems in a state of continuous change for 100,000 years. PMID:23908226

  12. Interactions Between Climate Change, Fire and Invasive Plants in California Ecosystems

    NASA Astrophysics Data System (ADS)

    Keeley, J. E.

    2007-12-01

    Changes in fire regimes are predicted in many climate change scenarios. The types of changes are greatly affected by the fuel structure of the ecosystem and different trajectories of change are expected in surface fire regimes than in crown fire regimes. However, in the multi-factorial world of natural ecosystems, climate is only one of the drivers of future change and some of the known threats to ecosystem stability are expected to push the system over particular thresholds of tolerance very rapidly. Invasive species have been widely recognized as drivers of ecosystem change, often generating feedback effects that alter fuel structure and future fire behavior. Human demographic changes, and the concomitant changes in anthropogenic fire ignitions are an additional threat to future ecosystem stability. I will address how these factors might interact with climate change in ecosystems of very different fuel structure, including surface fire ponderosa pine forests and crown fire chaparral shrublands in California.

  13. Global Change Impacts on Mangrove Ecosystems

    USGS Publications Warehouse

    McKee, Karen L.

    2004-01-01

    Mangroves are tropical/subtropical communities of primarily tree species that grow in the intertidal zone. These tidal forests are important coastal ecosystems that are valued for a variety of ecological and societal goods and services. Major local threats to mangrove ecosystems worldwide include clearcutting and trimming of forests for urban, agricultural, or industrial expansion; hydrological alterations; toxic chemical spills; and eutrophication. In many countries with mangroves, much of the human population resides in the coastal zone, and their activities often negatively impact the integrity of mangrove forests. In addition, eutrophication, which is the process whereby nutrients build up to higher than normal levels in a natural system, is possibly one of the most serious threats to mangroves and associated ecosystems such as coral reefs. Scientists with the U.S. Geological Survey (USGS) at the National Wetlands Research Center are working to more fully understand global impacts on these significant ecosystems. Changes in climate and other factors may also affect mangroves, but in complex ways. Global warming may promote expansion of mangrove forests to higher latitudes and accelerate sea-level rise through melting of polar ice or steric expansion of oceans. Changes in sea level would alter flooding patterns and the structure and areal extent of mangroves. Climate change may also alter rainfall patterns, which would in turn change local salinity regimes and competitive interactions of mangroves with other wetland species. Increases in frequency or intensity of tropical storms and hurricanes in combination with sea-level rise may alter erosion and sedimentation rates in mangrove forests. Another global change factor that may directly affect mangrove growth is increased atmospheric carbon dioxide (CO2), caused by burning of fossil fuels and other factors. Elevated CO2 concentration may increase mangrove growth by stimulating photosynthesis or improving water

  14. Indigenous people's detection of rapid ecological change.

    PubMed

    Aswani, Shankar; Lauer, Matthew

    2014-06-01

    When sudden catastrophic events occur, it becomes critical for coastal communities to detect and respond to environmental transformations because failure to do so may undermine overall ecosystem resilience and threaten people's livelihoods. We therefore asked how capable of detecting rapid ecological change following massive environmental disruptions local, indigenous people are. We assessed the direction and periodicity of experimental learning of people in the Western Solomon Islands after a tsunami in 2007. We compared the results of marine science surveys with local ecological knowledge of the benthos across 3 affected villages and 3 periods before and after the tsunami. We sought to determine how people recognize biophysical changes in the environment before and after catastrophic events such as earthquakes and tsunamis and whether people have the ability to detect ecological changes over short time scales or need longer time scales to recognize changes. Indigenous people were able to detect changes in the benthos over time. Detection levels differed between marine science surveys and local ecological knowledge sources over time, but overall patterns of statistically significant detection of change were evident for various habitats. Our findings have implications for marine conservation, coastal management policies, and disaster-relief efforts because when people are able to detect ecological changes, this, in turn, affects how they exploit and manage their marine resources. PMID:24528101

  15. Changes in ecosystem resilience detected in automated measures of ecosystem metabolism during a whole-lake manipulation.

    PubMed

    Batt, Ryan D; Carpenter, Stephen R; Cole, Jonathan J; Pace, Michael L; Johnson, Robert A

    2013-10-22

    Environmental sensor networks are developing rapidly to assess changes in ecosystems and their services. Some ecosystem changes involve thresholds, and theory suggests that statistical indicators of changing resilience can be detected near thresholds. We examined the capacity of environmental sensors to assess resilience during an experimentally induced transition in a whole-lake manipulation. A trophic cascade was induced in a planktivore-dominated lake by slowly adding piscivorous bass, whereas a nearby bass-dominated lake remained unmanipulated and served as a reference ecosystem during the 4-y experiment. In both the manipulated and reference lakes, automated sensors were used to measure variables related to ecosystem metabolism (dissolved oxygen, pH, and chlorophyll-a concentration) and to estimate gross primary production, respiration, and net ecosystem production. Thresholds were detected in some automated measurements more than a year before the completion of the transition to piscivore dominance. Directly measured variables (dissolved oxygen, pH, and chlorophyll-a concentration) related to ecosystem metabolism were better indicators of the approaching threshold than were the estimates of rates (gross primary production, respiration, and net ecosystem production); this difference was likely a result of the larger uncertainties in the derived rate estimates. Thus, relatively simple characteristics of ecosystems that were observed directly by the sensors were superior indicators of changing resilience. Models linked to thresholds in variables that are directly observed by sensor networks may provide unique opportunities for evaluating resilience in complex ecosystems. PMID:24101479

  16. Climate Change Impacts on Marine Ecosystems

    NASA Astrophysics Data System (ADS)

    Doney, Scott C.; Ruckelshaus, Mary; Emmett Duffy, J.; Barry, James P.; Chan, Francis; English, Chad A.; Galindo, Heather M.; Grebmeier, Jacqueline M.; Hollowed, Anne B.; Knowlton, Nancy; Polovina, Jeffrey; Rabalais, Nancy N.; Sydeman, William J.; Talley, Lynne D.

    2012-01-01

    In marine ecosystems, rising atmospheric CO2 and climate change are associated with concurrent shifts in temperature, circulation, stratification, nutrient input, oxygen content, and ocean acidification, with potentially wide-ranging biological effects. Population-level shifts are occurring because of physiological intolerance to new environments, altered dispersal patterns, and changes in species interactions. Together with local climate-driven invasion and extinction, these processes result in altered community structure and diversity, including possible emergence of novel ecosystems. Impacts are particularly striking for the poles and the tropics, because of the sensitivity of polar ecosystems to sea-ice retreat and poleward species migrations as well as the sensitivity of coral-algal symbiosis to minor increases in temperature. Midlatitude upwelling systems, like the California Current, exhibit strong linkages between climate and species distributions, phenology, and demography. Aggregated effects may modify energy and material flows as well as biogeochemical cycles, eventually impacting the overall ecosystem functioning and services upon which people and societies depend.

  17. Testing paradigms of ecosystem change under climate warming in Antarctica.

    PubMed

    Melbourne-Thomas, Jessica; Constable, Andrew; Wotherspoon, Simon; Raymond, Ben

    2013-01-01

    Antarctic marine ecosystems have undergone significant changes as a result of human activities in the past and are now responding in varied and often complicated ways to climate change impacts. Recent years have seen the emergence of large-scale mechanistic explanations-or "paradigms of change"-that attempt to synthesize our understanding of past and current changes. In many cases, these paradigms are based on observations that are spatially and temporally patchy. The West Antarctic Peninsula (WAP), one of Earth's most rapidly changing regions, has been an area of particular research focus. A recently proposed mechanistic explanation for observed changes in the WAP region relates changes in penguin populations to variability in krill biomass and regional warming. While this scheme is attractive for its simplicity and chronology, it may not account for complex spatio-temporal processes that drive ecosystem dynamics in the region. It might also be difficult to apply to other Antarctic regions that are experiencing some, though not all, of the changes documented for the WAP. We use qualitative network models of differing levels of complexity to test paradigms of change for the WAP ecosystem. Importantly, our approach captures the emergent effects of feedback processes in complex ecological networks and provides a means to identify and incorporate uncertain linkages between network elements. Our findings highlight key areas of uncertainty in the drivers of documented trends, and suggest that a greater level of model complexity is needed in devising explanations for ecosystem change in the Southern Ocean. We suggest that our network approach to evaluating a recent and widely cited paradigm of change for the Antarctic region could be broadly applied in hypothesis testing for other regions and research fields. PMID:23405116

  18. Basin-wide Assessment of Climate Change Impacts on Ecosystems and Biodiversity

    EPA Science Inventory

    Mekong ecosystems are under pressure from a number of "drivers", including rapid economic development, population growth, unsustainable resource use, and climate change. Ecological modeling can help assess vulnerability and impacts of these drivers on the Lower Mekong Basin.

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

    SciTech Connect

    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.

  20. Population growth and the changing ecosystem in Mindanao.

    PubMed

    Magdalena, F V

    1996-04-01

    Mindanao is the second largest island in the Philippines. Once considered the greenest spot on earth, it has since been highly exploited. This paper discusses the changing ecosystem of the island as a result of rapid population growth since the early 1900s. Not much is known about Mindanao before 1900. From 1913, however, population grew on Mindanao as the American colonial government established agricultural colonies to open up the south for trade and development. Colonial settlement together with migration and natural population increase led to environmental resource degradation and the displacement of indigenous communities such as the Moros and Lumads. Legal and illegal logging and rampant kaingin agriculture have also stressed the environment. The opening of the Mindanao frontier, Philippine development, the Great Migration, incursion of the Mindanao upland, deforestation, the displacement of indigenous communities, and the possible maintenance and rehabilitation of the ecosystem are discussed. PMID:12292068

  1. Global climate change and freshwater ecosystems

    SciTech Connect

    Firth, P.; Fisher, S.G.

    1992-01-01

    This book is based on a symposium held in May 1990, sponsored by NASA, US EPA, and the North American Benthological Society. It focuses on the potential interactions between climate change and freshwater ecosystems. The assumption of global warming 2-5 degrees occurring in the next century was presented to the authors by the editors, and each author was asked to comment on how this warming might affect their particular system or process of interest. The book deals primarily with streams in the USA. Other chapters deal with the following topics: mechanisms driving global climate change; remote sensing; wetlands; lakes; general issues related to water resources and regional studies as they apply to flowing water.

  2. Shifting seasons, climate change and ecosystem consequences

    NASA Astrophysics Data System (ADS)

    Thackeray, Stephen; Henrys, Peter; Hemming, Deborah; Huntingford, Chris; Bell, James; Leech, David; Wanless, Sarah

    2014-05-01

    In recent decades, the seasonal timing of many biological events (e.g. flowering, breeding, migration) has shifted. These phenological changes are believed to be one of the most conspicuous biological indicators of climate change. Rates and directions of phenological change have differed markedly among species, potentially threatening the seasonal synchrony of key species interactions and ultimately ecosystem functioning. Differences in phenological change among-species at different trophic levels, and with respect to other broad species traits, are likely to be driven by variations in the climatic sensitivity of phenological events. However, as yet, inconsistencies in analytical methods have hampered broad-scale assessments of variation in climate sensitivity among taxonomic and functional groups of organisms. In this presentation, results will be presented from a current collaborative project (http://www.ceh.ac.uk/sci_programmes/shifting-seasons-uk.html) in which many UK long-term data sets are being integrated in order to assess relationships between temperature/precipitation, and the timing of seasonal events for a wide range of plants and animals. Our aim is to assess which organism groups (in which locations/habitats) are most sensitive to climate. Furthermore, the role of anthropogenic climate change as a driver of phenological change is being assessed.

  3. When vegetation change alters ecosystem water availability.

    PubMed

    Scott, Russell L; Huxman, Travis E; Barron-Gafford, Greg A; Darrel Jenerette, G; Young, Jessica M; Hamerlynck, Erik P

    2014-07-01

    The combined effects of vegetation and climate change on biosphere-atmosphere water vapor (H2 O) and carbon dioxide (CO2 ) exchanges are expected to vary depending, in part, on how biotic activity is controlled by and alters water availability. This is particularly important when a change in ecosystem composition alters the fractional covers of bare soil, grass, and woody plants so as to influence the accessibility of shallower vs. deeper soil water pools. To study this, we compared 5 years of eddy covariance measurements of H2 O and CO2 fluxes over a riparian grassland, shrubland, and woodland. In comparison with the surrounding upland region, groundwater access at the riparian sites increased net carbon uptake (NEP) and evapotranspiration (ET), which were sustained over more of the year. Among the sites, the grassland used less of the stable groundwater resource, and increasing woody plant density decoupled NEP and ET from incident precipitation (P), resulting in greater exchange rates that were less variable year to year. Despite similar gross patterns, how groundwater accessibility affected NEP was more complex than ET. The grassland had higher respiration (Reco ) costs. Thus, while it had similar ET and gross carbon uptake (GEP) to the shrubland, grassland NEP was substantially less. Also, grassland carbon fluxes were more variable due to occasional flooding at the site, which both stimulated and inhibited NEP depending upon phenology. Woodland NEP was large, but surprisingly similar to the less mature, sparse shrubland, even while having much greater GEP. Woodland Reco was greater than the shrubland and responded strongly and positively to P, which resulted in a surprising negative NEP response to P. This is likely due to the large accumulation of carbon aboveground and in the surface soil. These long-term observations support the strong role that water accessibility can play when determining the consequences of ecosystem vegetation change. PMID:24777485

  4. Climate Change Altered Disturbance Regimes in High Elevation Pine Ecosystems

    NASA Astrophysics Data System (ADS)

    Logan, J. A.

    2004-12-01

    Insects in aggregate are the greatest cause of forest disturbance. Outbreaks of both native and exotic insects can be spectacular events in both their intensity and spatial extent. In the case of native species, forest ecosystems have co-evolved (or at least co-adapted) in ways that incorporate these disturbances into the normal cycle of forest maturation and renewal. The time frame of response to changing climate, however, is much shorter for insects (typically one year) than for their host forests (decades or longer). As a result, outbreaks of forest insects, particularly bark beetles, are occurring at unprecedented levels throughout western North America, resulting in the loss of biodiversity and potentially entire ecosystems. In this talk, I will describe one such ecosystem, the whitebark pine association at high elevations in the north-central Rocky Mountains of the United States. White bark pines are keystone species, which in consort with Clark's nutcracker, build entire ecosystems at high elevations. These ecosystems provide valuable ecological services, including the distribution and abundance of water resources. I will briefly describe the keystone nature of whitebark pine and the historic role of mountain pine beetle disturbance in these ecosystems. The mountain pine beetle is the most important outbreak insect in forests of the western United States. Although capable of spectacular outbreak events, in historic climate regimes, outbreak populations were largely restricted to lower elevation pines; for example, lodgepole and ponderosa pines. The recent series of unusually warm years, however, has allowed this insect to expand its range into high elevation, whitebark pine ecosystems with devastating consequences. The aspects of mountain pine beetle thermal ecology that has allowed it to capitalize so effectively on a warming climate will be discussed. A model that incorporates critical thermal attributes of the mountain pine beetle's life cycle was

  5. Preferred ecosystem characteristics: their food and health relevance to China's rapid urbanisation.

    PubMed

    Gibson, Valerie; Zhu, Yong-Guan; Ge, Rubing; Wahlqvist, Mark L

    2015-01-01

    For most of its history, China has supported a growing population through food systems which have been mutually inclusive of people and their locality. This trajectory has required adequate ecosystem maintenance or humanised reformulation and a high degree of recyclable nutrient flow. The 'tipping point' in habitat sustainability has come with the size and demographic structure of China's population to one that is ageing, with modernisation of its infrastructure and increased expectations of better livelihoods, standards of living and health. In order to meet these expectations, China has embarked on rapid urbanisation for upwards of 300 million people over the next 15-20 years and to do so taking account of the environmental limitations. The process will radically change rural as well as urban China and the systems which connect them. Chief among these will be ecosystems in number and type along with the food and health systems integral to them. To minimise ecological damage and optimise the benefits to people and place, describing, monitoring and managing the process will be paramount. The present paper is a situational analysis of health as it may be ecologically favoured or disordered (Ecosystem Health Disorders) and of the food systems on which the environment and health depend. An effort is made to enumerate the current situation in China in a way that might enable the optimisation of humanised ecosystems. PMID:26693739

  6. Future of African terrestrial biodiversity and ecosystems under anthropogenic climate change

    NASA Astrophysics Data System (ADS)

    Midgley, Guy F.; Bond, William J.

    2015-09-01

    Projections of ecosystem and biodiversity change for Africa under climate change diverge widely. More than other continents, Africa has disturbance-driven ecosystems that diversified under low Neogene CO2 levels, in which flammable fire-dependent C4 grasses suppress trees, and mega-herbivore action alters vegetation significantly. An important consequence is metastability of vegetation state, with rapid vegetation switches occurring, some driven by anthropogenic CO2-stimulated release of trees from disturbance control. These have conflicting implications for biodiversity and carbon sequestration relevant for policymakers and land managers. Biodiversity and ecosystem change projections need to account for both disturbance control and direct climate control of vegetation structure and function.

  7. Impacts of climate change on biodiversity, ecosystems, and ecosystem services: technical input to the 2013 National Climate Assessment

    USGS Publications Warehouse

    Staudinger, Michelle D.; Grimm, Nancy B.; Staudt, Amanda; Carter, Shawn L.; Stuart, F. Stuart, III; Kareiva, Peter; Ruckelshaus, Mary; Stein, Bruce A.

    2012-01-01

    second cross-cutting topic is the rapidly advancing field of climate adaptation, where there has been significant progress in developing the conceptual framework, planning approaches, and strategies for safeguarding biodiversity and other ecological resources. At the same time, ecosystem-based adaptation is becoming more prominent as a way to utilize ecosystem services to help human systems adapt to climate change. In this summary, we present key findings of the technical input, focusing on themes that can be found throughout the report. Thus, this summary takes a more integrated look at the question of how climate change is affecting our ecological resources, the implications for humans, and possible response strategies. This integrated approach better reflects the impacts of climate in the real world, where changes in ecosystem structure or function will alter the viability of different species and the efficacy of ecosystem services. Likewise, adaptation to climate change will simultaneously address a range of conservation goals. Case studies are used to illustrate this complete picture throughout the report; a snapshot of one case study, 2011 Las Conchas, New Mexico Fire, is included in this summary.

  8. Effects of temperature changes on groundwater ecosystems

    NASA Astrophysics Data System (ADS)

    Griebler, Christian; Kellermann, Claudia; Schreglmann, Kathrin; Lueders, Tillmann; Brielmann, Heike; Schmidt, Susanne; Kuntz, David; Walker-Hertkorn, Simone

    2014-05-01

    The use of groundwater as a carrier of thermal energy is becoming more and more important as a sustainable source of heating and cooling. At the same time, the present understanding of the effects of aquifer thermal usage on geochemical and biological aquifer ecosystem functions is extremely limited. Recently we started to assess the effects of temperature changes in groundwater on the ecological integrity of aquifers. In a field study, we have monitored hydrogeochemical, microbial, and faunal parameters in groundwater of an oligotrophic aquifer in the vicinity of an active thermal discharge facility. The observed seasonal variability of abiotic and biotic parameters between wells was considerable. Yet, due to the energy-limited conditions no significant temperature impacts on bacterial or faunal abundances and on bacterial productivity were observed. In contrast, the diversity of aquifer bacterial communities and invertebrate fauna was either positively or negatively affected by temperature, respectively. In follow-up laboratory experiments temperature effects were systematically evaluated with respect to energy limitation (e.g. establishment of unlimited growth conditions), geochemistry (e.g. dynamics of DOC and nutrients), microbiology (e.g. survival of pathogens), and fauna (temperature preference and tolerance). First, with increased nutrient and organic carbon concentrations even small temperature changes revealed microbiological dynamics. Second, considerable amounts of adsorbed DOC were mobilized from sediments of different origin with an increase in temperatures. No evidence was obtained for growth of pathogenic bacteria and extended survival of viruses at elevated temperatures. Invertebrates clearly preferred natural thermal conditions (10-12°C), where their highest frequency of appearance was measured in a temperature gradient. Short-term incubations (48h) of invertebrates in temperature dose-response tests resulted in LT50 (lethal temperature) values

  9. RESTORING COASTAL ECOSYSTEMS: ABRUPT CLIMATE CHANGE

    EPA Science Inventory

    Consensus exists that U.S. coastal ecosystems are severely degraded due to a variety of human-factors requiring large financial expenditures to restore and manage. Yet, even as controversy surrounds human factors in ecosystem degradation in the Gulf of Mexico, Chesapeake Bay, an...

  10. Rapidly restoring biological soil crusts and ecosystem functions in a severely disturbed desert ecosystem.

    PubMed

    Chiquoine, Lindsay P; Abella, Scott R; Bowker, Matthew A

    2016-06-01

    Restoring biological soil crusts (biocrusts) in degraded drylands can contribute to recovery of ecosystem functions that have global implications, including erosion resistance and nutrient cycling. To examine techniques for restoring biocrusts, we conducted a replicated, factorial experiment on recently abandoned road surfaces by applying biocrust inoculation (salvaged and stored dry for two years), salvaged topsoil, an abiotic soil amendment (wood shavings), and planting of a dominant perennial shrub (Ambrosia dumosa). Eighteen months after treatments, we measured biocrust abundance and species composition, soil chlorophyll a content and fertility, and soil resistance to erosion. Biocrust addition significantly accelerated biocrust recovery on disturbed soils, including increasing lichen and moss cover and cyanobacteria colonization. Compared to undisturbed controls, inoculated plots had similar lichen and moss composition, recovered 43% of total cyanobacteria density, had similar soil chlorophyll content, and exhibited recovery of soil fertility and soil stability. Inoculation was the only treatment that generated lichen and moss cover. Topsoil application resulted in partial recovery of the cyanobacteria community and soil properties. Compared to untreated disturbed plots, topsoil application without inoculum increased cyanobacteria density by 186% and moderately improved soil chlorophyll and ammonium content and soil stability. Topsoil application produced 22% and 51% of the cyanobacteria density g⁻¹ soil compared to undisturbed and inoculated plots, respectively. Plots not treated with either topsoil or inoculum had significantly lower cyanobacteria density, soil chlorophyll and ammonium concentrations, and significantly higher soil nitrate concentration. Wood shavings and Ambrosia had no influence on biocrust lichen and moss species recovery but did affect cyanobacteria composition and soil fertility. Inoculation of severely disturbed soil with native

  11. Abrupt climate change and collapse of deep-sea ecosystems

    USGS Publications Warehouse

    Yasuhara, Moriaki; Cronin, T. M.; Demenocal, P.B.; Okahashi, H.; Linsley, B.K.

    2008-01-01

    We investigated the deep-sea fossil record of benthic ostracodes during periods of rapid climate and oceanographic change over the past 20,000 years in a core from intermediate depth in the northwestern Atlantic. Results show that deep-sea benthic community "collapses" occur with faunal turnover of up to 50% during major climatically driven oceanographic changes. Species diversity as measured by the Shannon-Wiener index falls from 3 to as low as 1.6 during these events. Major disruptions in the benthic communities commenced with Heinrich Event 1, the Inter-Aller??d Cold Period (IACP: 13.1 ka), the Younger Dryas (YD: 12.9-11.5 ka), and several Holocene Bond events when changes in deep-water circulation occurred. The largest collapse is associated with the YD/IACP and is characterized by an abrupt two-step decrease in both the upper North Atlantic Deep Water assemblage and species diversity at 13.1 ka and at 12.2 ka. The ostracode fauna at this site did not fully recover until ???8 ka, with the establishment of Labrador Sea Water ventilation. Ecologically opportunistic slope species prospered during this community collapse. Other abrupt community collapses during the past 20 ka generally correspond to millennial climate events. These results indicate that deep-sea ecosystems are not immune to the effects of rapid climate changes occurring over centuries or less. ?? 2008 by The National Academy of Sciences of the USA.

  12. The added complications of climate change: understanding and managing biodiversity and ecosystems

    USGS Publications Warehouse

    Amanda Staudt; Allison K. Leidner; Jennifer Howard; Kate A. Brauman; Jeffrey S. Dukes; Hansen, Lara J.; Paukert, Craig; Sabo, John L.; Solorzano, Luis A.

    2013-01-01

    Ecosystems around the world are already threatened by land-use and land-cover change, extraction of natural resources, biological disturbances, and pollution. These environmental stressors have been the primary source of ecosystem degradation to date, and climate change is now exacerbating some of their effects. Ecosystems already under stress are likely to have more rapid and acute reactions to climate change; it is therefore useful to understand how multiple stresses will interact, especially as the magnitude of climate change increases. Understanding these interactions could be critically important in the design of climate adaptation strategies, especially because actions taken by other sectors (eg energy, agriculture, transportation) to address climate change may create new ecosystem stresses.

  13. Assessing and managing freshwater ecosystems vulnerable to global change

    USGS Publications Warehouse

    Angeler, David G.; Allen, Craig R.; Birge, Hannah E.; Drakare, Stina; McKie, Brendan G.; Johnson, Richard K.

    2014-01-01

    Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change.

  14. Ecosystem service supply and vulnerability to global change in Europe.

    PubMed

    Schröter, Dagmar; Cramer, Wolfgang; Leemans, Rik; Prentice, I Colin; Araújo, Miguel B; Arnell, Nigel W; Bondeau, Alberte; Bugmann, Harald; Carter, Timothy R; Gracia, Carlos A; de la Vega-Leinert, Anne C; Erhard, Markus; Ewert, Frank; Glendining, Margaret; House, Joanna I; Kankaanpää, Susanna; Klein, Richard J T; Lavorel, Sandra; Lindner, Marcus; Metzger, Marc J; Meyer, Jeannette; Mitchell, Timothy D; Reginster, Isabelle; Rounsevell, Mark; Sabaté, Santi; Sitch, Stephen; Smith, Ben; Smith, Jo; Smith, Pete; Sykes, Martin T; Thonicke, Kirsten; Thuiller, Wilfried; Tuck, Gill; Zaehle, Sönke; Zierl, Bärbel

    2005-11-25

    Global change will alter the supply of ecosystem services that are vital for human well-being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions. PMID:16254151

  15. Plant ecology. Anthropogenic environmental changes affect ecosystem stability via biodiversity.

    PubMed

    Hautier, Yann; Tilman, David; Isbell, Forest; Seabloom, Eric W; Borer, Elizabeth T; Reich, Peter B

    2015-04-17

    Human-driven environmental changes may simultaneously affect the biodiversity, productivity, and stability of Earth's ecosystems, but there is no consensus on the causal relationships linking these variables. Data from 12 multiyear experiments that manipulate important anthropogenic drivers, including plant diversity, nitrogen, carbon dioxide, fire, herbivory, and water, show that each driver influences ecosystem productivity. However, the stability of ecosystem productivity is only changed by those drivers that alter biodiversity, with a given decrease in plant species numbers leading to a quantitatively similar decrease in ecosystem stability regardless of which driver caused the biodiversity loss. These results suggest that changes in biodiversity caused by drivers of environmental change may be a major factor determining how global environmental changes affect ecosystem stability. PMID:25883357

  16. Rapid demise and recovery of plant ecosystems across the end-Permian extinction event

    NASA Astrophysics Data System (ADS)

    Hochuli, Peter A.; Hermann, Elke; Vigran, Jorunn Os; Bucher, Hugo; Weissert, Helmut

    2010-12-01

    The end-Permian extinction event was the most pronounced biotic and ecological crisis in the history of the Earth. It is assumed that over 80% of marine genera disappeared, and that this event had a major impact on the evolution of marine organisms. The impact of this event on terrestrial biota is poorly known and a matter of controversial discussions. In contrast to the fundamental changes in marine fauna most major groups of plants range from the Late Palaeozoic into the Mesozoic. Consequently the impact of the end-Permian extinction event on the evolution of plants was often regarded as minor. However, major changes in the composition of the plant communities have been documented and a number of catastrophic scenarios have been envisioned — including the almost total destruction of plant ecosystems. Based on expanded sections from the Southern Barents Sea (Northern Norway) we trace mid-latitudinal terrestrial ecosystems across the Permo-Triassic transition with a time resolution in the order of 10 kyr, based on a high resolution C org-isotope stratigraphy. Our results show that the floral turnovers are linked with major changes in the C-isotope record and hence with global carbon cycling. The palynological records document the successive steps in the evolution of terrestrial ecosystems. After gradual changes during the latest Permian, plant ecosystems suffered from a major environmental perturbation leading to a rapid turnover from gymnosperm dominated ecosystems to assemblages dominated by lycopods. The dominance of the lycopods, expressed in a spore-spike, represents a relatively short-lived event in the order of 10 kyr. This perturbation of the terrestrial ecosystems preceded the globally recognized negative δ 13C org isotope spike by up to 100 kyr. It coincides with a first end-Permian negative shift of the C-isotope curve and was probably induced by a first major perturbation of the chemistry of the atmosphere, related to the onset of the volcanic

  17. IMPACT OF GLOBAL CHANGE OF TERRESTRIAL ECOSYSTEMS: FRAMEWORKS FOR EVALUATING AGROECOSYSTEM AND FOREST ECOSYSTEM EFFECTS

    EPA Science Inventory

    The United States Environmental Protection Agency's (EPA) Global Climate Research Program (GCRP) is determining the effects of climate change on terrestrial ecosystems. his paper describes a general ecological risk assessment model as well as specific conceptual models for urrent...

  18. FISHER INFORMATION AND ECOSYSTEM REGIME CHANGES

    EPA Science Inventory

    Following Fisher’s work, we propose two different expressions for the Fisher Information along with Shannon Information as a means of detecting and assessing shifts between alternative ecosystem regimes. Regime shifts are a consequence of bifurcations in the dynamics of an ecosys...

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

    SciTech Connect

    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.

  20. Geoengineering and the Risk of Rapid Climate Change

    NASA Astrophysics Data System (ADS)

    Ross, A. J.; Matthews, D.

    2008-12-01

    climate system. Many ecosystems would be significantly stressed by the high rates of temperature change shown in this study, which could compromise ecosystems' ability to adapt to climate change There are also possible implications of rapid temperature change for other aspects of the climate system, such as the strength of the meridional overturning circulation. Based on the results of this study, we argue that the risk of rapid climate change following the abrupt removal of geoengineering could constitute increased risk of dangerous anthropogenic interference in the climate system.

  1. Agricultural ecosystem effects on trace gases and global climate change

    SciTech Connect

    Not Available

    1993-01-01

    Global climate change is an issue that has been thrust to the forefront of scientific, political, and general community interest. In the span of this human generation, the earth's climate is expected to change more rapidly than it has over any comparable period of recorded history. Some of the changes will result from natural processes, beyond human control, but much of this change is subject to anthropogenic influence arising from processes that are only beginning to be understood. Increasing concentrations of atmospheric radiatively active trace gases are being inadvertently affected by fossil fuel combustion; but other activities of industry, agriculture, forestry, changing land-use practices, waste disposal, and transportation also affect the chemical composition of the atmosphere. The measured and projected changes of the atmospheric concentrations of radiatively active trace gases have been modeled and estimated to predict changes in the global climate. Accuracy and reliability of these predictions are the subject of considerable debate among scientists and other concerned individuals, groups, and governmental agencies throughout the world. The objective of this book is to provide a review of current knowledge on the measurement of radiatively active trace gases in agricultural ecosystems and the effect of agriculture on the atmospheric concentrations of these gases. This book is compiled from written papers presented at a symposium entitled, Agroecosystem Effects on Radiatively Important Trace Gases and Global Climate Change, held at the American Society of Agronomy Meetings in Denver, CO, 27 Oct.-1 Nov. 1991. Fourteen chapters have been processed separately for inclusion in the appropriate data bases.

  2. Soil community structure and ecosystem C cycling in arid ecosystems experiencing multiple environmental changes

    NASA Astrophysics Data System (ADS)

    Pavao-Zuckerman, M. A.; Cable, J. M.; Huxman, T. E.; Scott, R. L.; Williams, D. G.

    2005-12-01

    Despite the importance of soil carbon cycling to the response of water-limited ecosystems to global change, our understanding of this ecosystem component is still in its infancy. Adding to the complexity in knowledge building, ecosystems are exposed to simultaneous multiple shifts within global change scenarios. For example, semiarid grasslands in southern Arizona are currently undergoing encroachment by woody plants at the same time that climate change models predict increases in frequency and magnitude of precipitation inputs over the next 50 years. We are investigating how heterogeneity of plant cover mediates the response of soil community structure and ecosystem C cycling to seasonal monsoon rain inputs. Field plots were established in a mesquite shrubland in the San Pedro River Basin, AZ that are dominated by either: Sporobulus wrightii, medium sized Prosopis velutina, or large Prosopis velutina, additional plots were located in intercanopy areas. Both increased quantity and quality of litter inputs to the soil component, and physical influences of the shrubs on ecosystem water and energy budgets affects plots influenced by the development of Prosopis. Plant species influenced the response of soil microbial biomass to precipitation pulses. Plant cover also influenced the dynamics of soil nematodes. Magnitude of precipitation inputs and plant cover interact to affect the abundance of trophic group abundances and food web structure. These results will be discussed vis-à-vis the importance of soil organisms for driving ecosystem dynamics, and the appropriateness of dominant paradigms in arid land ecology (notably the pulse-reserve paradigm) for understanding soil components of arid ecosystems. Shifts in soil flora and fauna have important implications for ecosystem C-cycling via alterations of trophic dynamics, and the contribution of heterotrophic respiration to C efflux from ecosystems.

  3. CLIMATE CHANGE AND ECOSYSTEMS OF THE MID-ATLANTIC REGION

    EPA Science Inventory

    This paper discusses the current status of forested, wetland, freshwater and coastal ecosystems; the combined impacts of habitat alteration, pollution and non-native invasive species on those systems; how climatic changes could interact with existing stresses; potential managemen...

  4. Rapid assessment system based on ecosystem services for retrofitting of sustainable drainage systems.

    PubMed

    Scholz, Miklas

    2014-01-01

    Sustainable drainage systems (SuDS) design and retrofitting is predominantly based on expert opinion supported by descriptive guidance documents. The aim of this paper is to develop an innovative rapid decision support tool based on novel ecosystem service variables for retrofitting of key SuDS techniques. This unique tool proposes the retrofitting of a SuDS technique that obtained the highest ecosystem service score for a specific urban site. This approach contrasts with methods based on traditional civil engineering judgement linked to standard variables based on community and environment studies. For a case study area (Greater Manchester), a comparison with the traditional approach of determining community and environment variables indicates that permeable pavements, filter strips, swales, ponds, constructed wetlands and below-ground storage tanks are generally less preferred than infiltration trenches, soakaways and infiltration basins. However, permeable pavements and belowground storage tanks also received relatively high scores, because of their great potential impact in terms of water quality improvement and flood control, respectively. The application of the proposed methodology will lead to changes of the sustainable drainage infrastructure in the urban landscape. PMID:24701926

  5. Quantifying changes in multiple ecosystem services during 1992-2012 in the Sanjiang Plain of China.

    PubMed

    Wang, Zongming; Mao, Dehua; Li, Lin; Jia, Mingming; Dong, Zhangyu; Miao, Zhenghong; Ren, Chunying; Song, Changchun

    2015-05-01

    Rapid and periodic assessment of the impact of land cover changes on ecosystem services at regional levels is essential to understanding services and sustainability of ecosystems. This study focused on quantifying and assessing changes of multiple ecosystem services in the Sanjiang Plain of China as a result of land cover changes over the period of 1992-2012. This region is important for its large area of natural wetlands and intensive agriculture. The ecosystem services that were assessed for this region included its regulating services (water yield and ecosystem carbon stocks), supporting services (suitable waterbird habitats), and provisioning services (food production), and the approach to the assessment was composed of the surface energy balance algorithms for land (SEBAL), soil survey re-sampling method and an empirical waterbird habitat suitability model. This large scale and integrated investigation represents the first systematic evaluation on the status of ecosystem carbon stocks in the Sanjiang Plain in addition to the development of an effective model for analysis of waterbird habitat suitability with the use of both remote sensing and geographic information systems (GIS). More importantly, the result from this study has confirmed trade-offs between ecosystem services and negative consequences to environment in this region. The trade-offs were typically manifested by increased water yield and significantly grown food production, which is in contrast with significant losses in ecosystem carbon stocks (-14%) and suitable waterbird habitats (-23%) mainly due to the conversion of land cover from wetland to farmland. This finding implies that land use planning and policy making for this economically important region should take ecosystem service losses into account in order to preserve its natural ecosystems in the best interest of society. PMID:25659310

  6. Changing climate and endangered high mountain ecosystems in Colombia.

    PubMed

    Ruiz, Daniel; Moreno, Hernán Alonso; Gutiérrez, María Elena; Zapata, Paula Andrea

    2008-07-15

    High mountain ecosystems are among the most sensitive environments to changes in climatic conditions occurring on global, regional and local scales. The article describes the changing conditions observed over recent years in the high mountain basin of the Claro River, on the west flank of the Colombian Andean Central mountain range. Local ground truth data gathered at 4150 m, regional data available at nearby weather stations, and satellite info were used to analyze changes in the mean and the variance, and significant trends in climatic time series. Records included minimum, mean and maximum temperatures, relative humidity, rainfall, sunshine, and cloud characteristics. In high levels, minimum and maximum temperatures during the coldest days increased at a rate of about 0.6 degrees C/decade, whereas maximum temperatures during the warmest days increased at a rate of about 1.3 degrees C/decade. Rates of increase in maximum, mean and minimum diurnal temperature range reached 0.6, 0.7, and 0.5 degrees C/decade. Maximum, mean and minimum relative humidity records showed reductions of about 1.8, 3.9 and 6.6%/decade. The total number of sunny days per month increased in almost 2.1 days. The headwaters exhibited no changes in rainfall totals, but evidenced an increased occurrence of unusually heavy rainfall events. Reductions in the amount of all cloud types over the area reached 1.9%/decade. In low levels changes in mean monthly temperatures and monthly rainfall totals exceeded + 0.2 degrees C and - 4% per decade, respectively. These striking changes might have contributed to the retreat of glacier icecaps and to the disappearance of high altitude water bodies, as well as to the occurrence and rapid spread of natural and man-induced forest fires. Significant reductions in water supply, important disruptions of the integrity of high mountain ecosystems, and dramatic losses of biodiversity are now a steady menu of the severe climatic conditions experienced by these

  7. Responses of arctic and alpine ecosystems to altered seasonality under climate change

    NASA Astrophysics Data System (ADS)

    Ernakovich, J. G.; Hopping, K. A.; Berdanier, A.; Simpson, R. T.; Kachergis, E. J.; Steltzer, H.; Wallenstein, M. D.

    2012-12-01

    Arctic and alpine ecosystems are largely structured by strong seasonal patterns in abiotic drivers, including solar radiation and air and soil temperature. Because air temperature and precipitation patterns are changing rapidly, the length of the growing season is increasing due to shifts in snowfall, earlier snowmelt in spring, and delayed snowfall in autumn. Although arctic and alpine environments are both characterized by short growing seasons, they differ in fundamental ways that will affect their responses to changing seasonality. We compare meteorological data from sixteen arctic and alpine sites and biological data from two arctic and two alpine sites. We propose that although alpine and arctic ecosystems appear similar under historical climate conditions, especially during the growing season, winter conditions and climate change will result in divergent responses. Biotic responses to changing seasonality will affect belowground and aboveground community composition, trophic dynamics, and the functioning of these ecosystems, including net carbon balance.

  8. CLIMATE CHANGE EFFECTS ON ECOSYSTEM SERVICES AND HUMAN HEALTH

    EPA Science Inventory

    Human health and well-being are and will be affected by climate change, both directly through changes in extreme weather events and indirectly through weather induced changes in societal systems and their supporting ecosystems. The goal of this study was to develop and apply a b...

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

    SciTech Connect

    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

  10. Climate change impacts on lake thermal dynamics and ecosystem vulnerabilities

    USGS Publications Warehouse

    Sahoo, G. B; Forrest, A. L; Schladow, S. G ;; Reuter, J. E; Coats, R.; Dettinger, Michael

    2016-01-01

    Using water column temperature records collected since 1968, we analyzed the impacts of climate change on thermal properties, stability intensity, length of stratification, and deep mixing dynamics of Lake Tahoe using a modified stability index (SI). This new SI is easier to produce and is a more informative measure of deep lake stability than commonly used stability indices. The annual average SI increased at 16.62 kg/m2/decade although the summer (May–October) average SI increased at a higher rate (25.42 kg/m2/decade) during the period 1968–2014. This resulted in the lengthening of the stratification season by approximately 24 d. We simulated the lake thermal structure over a future 100 yr period using a lake hydrodynamic model driven by statistically downscaled outputs of the Geophysical Fluid Dynamics Laboratory Model (GFDL) for two different green house gas emission scenarios (the A2 in which greenhouse-gas emissions increase rapidly throughout the 21st Century, and the B1 in which emissions slow and then level off by the late 21st Century). The results suggest a continuation and intensification of the already observed trends. The length of stratification duration and the annual average lake stability are projected to increase by 38 d and 12 d and 30.25 kg/m2/decade and 8.66 kg/m2/decade, respectively for GFDLA2 and GFDLB1, respectively during 2014–2098. The consequences of this change bear the hallmarks of climate change induced lake warming and possible exacerbation of existing water quality, quantity and ecosystem changes. The developed methodology could be extended and applied to other lakes as a tool to predict changes in stratification and mixing dynamics.

  11. Climate Change Has Cascading Ecological Effects on Mountain Ecosystems

    NASA Astrophysics Data System (ADS)

    Fagre, D. B.

    2007-12-01

    Evidence that ecosystems of the Northern Rocky Mountains are responding to climate change abounds. Alpine glaciers, as iconic landscape features, are disappearing rapidly with some glaciers losing one half of their area in five years. A model developed in the 1990s to predict future rates of melt has proved too conservative when compared to recent measurements. The largest glaciers in Glacier National Park are almost 10 years ahead of schedule in their retreat. The cascading ecological effects of losing glaciers in high-elevation watersheds includes shifts in distribution and dominance of temperature-sensitive stream macroinvertebrates as stream volume dwindles (or disappears) in later summer months and water temperatures increase. Critical spawning areas for threatened bull trout (Salvelinus confluentus) will be lost without the consistent supply of cold water that melting snow and ice provide and raise management questions regarding the efficacy of recovery efforts. Snowpacks are documented as becoming smaller and melting earlier in the spring, facilitating the invasion of subalpine meadows by trees and reducing habitat for current alpine wildlife. Even vital ecosystem disturbances, such as periodic snow avalanches that clear mountain slope forests, have been shown by tree-ring studies to be responsive to climatic trends and are likely to become less prevalent. Monitoring of high-elevation mountain environments is difficult and has largely been opportunistic despite the fact that these areas have experienced three times the temperature increases over the past century when compared to lowland environments. A system of alpine observatories is sorely needed. Tighter integration of mountains studies, and comparisons among diverse mountain systems of the western U.S. has been initiated by the USGS-sponsored Western Mountain Initiative and the Consortium for Integrated Climate Research in Western Mountains to begin addressing this need.

  12. Linking degradation status with ecosystem vulnerability to environmental change

    USGS Publications Warehouse

    Angeler, David G.; Baho, Didier L.; Allen, Craig R.; Johnson, Richard K.

    2015-01-01

    Environmental change can cause regime shifts in ecosystems, potentially threatening ecosystem services. It is unclear if the degradation status of ecosystems correlates with their vulnerability to environmental change, and thus the risk of future regime shifts. We assessed resilience in acidified (degraded) and circumneutral (undegraded) lakes with long-term data (1988–2012), using time series modeling. We identified temporal frequencies in invertebrate assemblages, which identifies groups of species whose population dynamics vary at particular temporal scales. We also assessed species with stochastic dynamics, those whose population dynamics vary irregularly and unpredictably over time. We determined the distribution of functional feeding groups of invertebrates within and across the temporal scales identified, and in those species with stochastic dynamics, and assessed attributes hypothesized to contribute to resilience. Three patterns of temporal dynamics, consistent across study lakes, were identified in the invertebrates. The first pattern was one of monotonic change associated with changing abiotic lake conditions. The second and third patterns appeared unrelated to the environmental changes we monitored. Acidified and the circumneutral lakes shared similar levels and patterns of functional richness, evenness, diversity, and redundancy for species within and across the observed temporal scales and for stochastic species groups. These similar resilience characteristics suggest that both lake types did not differ in vulnerability to the environmental changes observed here. Although both lake types appeared equally vulnerable in this study, our approach demonstrates how assessing systemic vulnerability by quantifying ecological resilience can help address uncertainty in predicting ecosystem responses to environmental change across ecosystems.

  13. Industrial arsenic contamination causes catastrophic changes in freshwater ecosystems

    PubMed Central

    Chen, Guangjie; Shi, Haibin; Tao, Jianshuang; Chen, Li; Liu, Yuanyuan; Lei, Guoliang; Liu, Xiaohai; Smol, John P.

    2015-01-01

    Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is known of the long-tem ecological consequences of pollutants such as arsenic. Here, our dated sediment records from two contaminated lakes in China faithfully document a 13.9 and 21.4-fold increase of total arsenic relative to pre-1950 background levels. Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga. Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions. PMID:26615891

  14. Industrial arsenic contamination causes catastrophic changes in freshwater ecosystems.

    PubMed

    Chen, Guangjie; Shi, Haibin; Tao, Jianshuang; Chen, Li; Liu, Yuanyuan; Lei, Guoliang; Liu, Xiaohai; Smol, John P

    2015-01-01

    Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is known of the long-tem ecological consequences of pollutants such as arsenic. Here, our dated sediment records from two contaminated lakes in China faithfully document a 13.9 and 21.4-fold increase of total arsenic relative to pre-1950 background levels. Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga. Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions. PMID:26615891

  15. Industrial arsenic contamination causes catastrophic changes in freshwater ecosystems

    NASA Astrophysics Data System (ADS)

    Chen, Guangjie; Shi, Haibin; Tao, Jianshuang; Chen, Li; Liu, Yuanyuan; Lei, Guoliang; Liu, Xiaohai; Smol, John P.

    2015-11-01

    Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is known of the long-tem ecological consequences of pollutants such as arsenic. Here, our dated sediment records from two contaminated lakes in China faithfully document a 13.9 and 21.4-fold increase of total arsenic relative to pre-1950 background levels. Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga. Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions.

  16. Widespread Climate Change in the Himalayas and Associated Changes in Local Ecosystems

    PubMed Central

    Shrestha, Uttam Babu; Gautam, Shiva; Bawa, Kamaljit S.

    2012-01-01

    Background Climate change in the Himalayas, a biodiversity hotspot, home of many sacred landscapes, and the source of eight largest rivers of Asia, is likely to impact the well-being of ∼20% of humanity. However, despite the extraordinary environmental, cultural, and socio-economic importance of the Himalayas, and despite their rapidly increasing ecological degradation, not much is known about actual changes in the two most critical climatic variables: temperature and rainfall. Nor do we know how changes in these parameters might impact the ecosystems including vegetation phenology. Methodology/Principal Findings By analyzing temperature and rainfall data, and NDVI (Normalized Difference Vegetation Index) values from remotely sensed imagery, we report significant changes in temperature, rainfall, and vegetation phenology across the Himalayas between 1982 and 2006. The average annual mean temperature during the 25 year period has increased by 1.5°C with an average increase of 0.06°C yr−1. The average annual precipitation has increased by 163 mm or 6.52 mmyr−1. Since changes in temperature and precipitation are immediately manifested as changes in phenology of local ecosystems, we examined phenological changes in all major ecoregions. The average start of the growing season (SOS) seems to have advanced by 4.7 days or 0.19 days yr−1 and the length of growing season (LOS) appears to have advanced by 4.7 days or 0.19 days yr−1, but there has been no change in the end of the growing season (EOS). There is considerable spatial and seasonal variation in changes in climate and phenological parameters. Conclusions/Significance This is the first time that large scale climatic and phenological changes at the landscape level have been documented for the Himalayas. The rate of warming in the Himalayas is greater than the global average, confirming that the Himalayas are among the regions most vulnerable to climate change. PMID:22615804

  17. Coastal Ecosystems and Climate Change: Is Modeling and Monitoring Enough?

    NASA Astrophysics Data System (ADS)

    Cronin, T. M.; Walker, H. A.

    2005-05-01

    Many coastal ecosystems are severely degraded due to a variety of human factors, requiring large and expensive monitoring and modeling efforts for restoration and management. Climate variability, including abrupt climate change, is seldom factored into coastal ecosystem management despite growing evidence for climate forcing of precipitation, river discharge, water quality, salinity, turbidity, faunal and phytoplankton dynamics, dissolved oxygen, and other ecosystem processes. We will review evidence from long-term monitoring records, multi-proxy paleoclimatic and paleoecological records, and climatic modeling that suggests that the effects of climate can override local and regional human activities and may potentially diminish the success of restoration efforts. Because ecosystem restoration often involves long-term objectives requiring decades to achieve, our focus will be on examples from sub-tropical and temperate estuaries in North America that show ecosystem response over decadal timescales to variability related to El Niño-Southern Oscillation, the Pacific Decadal Oscillation and the North Atlantic Oscillation. Climatic variability evident from paleo-records of the past few centuries exceeds that recorded in most 20th century monitoring records. This raises issues about the efficacy of local and regional ecosystem and hydrodynamic models designed to simulate ecosystem response to anthropogenic changes in sediment and nutrient input, fresh-water discharge, and land-use because such models, though tested with rigorous validation procedures, use calibration data sets limited to a few years. Thus, they might not be appropriate for simulating response to climatic extremes on the scale and duration of past events outside their calibration range. Understanding the complexities of ecosystem response to climatic forcing, especially in the context of local and regional ecosystem disturbance, raises formidable challenges, but attempts to integrate climate

  18. Climate Warming in Antarctica is Triggering Changes in Biodiversity and Terrestrial Ecosystems

    NASA Astrophysics Data System (ADS)

    Wall, D. H.

    2007-12-01

    Antarctica climate changes relating to ice and ocean currents have global impacts, but changes on terrestrial ecosystems in the Antarctic are less well known. This is partially due to the small area of exposed land, the apparent isolation, and lack of permanent residents. However, low diversity ecosystems, such as Antarctic polar deserts, are expected to be more vulnerable to global changes and are located in regions that are likely to see some of the greatest climate changes. Evidence is accumulating that terrestrial regions of Antarctica are experiencing substantial but variable responses to climate change and human disturbance. In the McMurdo Dry Valleys and in the rapidly warming Antarctic Peninsula region, temperature changes have a rippling effect that control habitat dynamics, species, carbon cycling, especially since these ecosystems are situated on a threshold between frozen and liquid water. Direct anthropogenic effects, including tourism and invasive species are also changing terrestrial communities but the magnitude and duration is dependent on numerous interacting factors. Global change scenarios incorporating species abundance, species traits, community change and monitoring of changes in biogeography will be important for determining alterations to ecosystem processes such as nutrient cycling.

  19. Committed ecosystem changes and contributions to climate recovery

    NASA Astrophysics Data System (ADS)

    Jones, C. D.; Lowe, J. A.; Liddicoat, S. K.; Betts, R. A.

    2009-04-01

    Future climate change and the carbon cycle are tightly coupled. Many studies have now shown positive feedbacks which amplify climate change, reduce the natural uptake of carbon and influence global emissions pathways to stabilisation. On the timescale of 1 or 2 centuries, this feedback is mainly due to the terrestrial biosphere. Here we assess to what extent the biosphere contributes to recovery of CO2 levels after a cessation of carbon emissions. We find that when significant climate change has weakened natural terrestrial carbon sinks, these sinks do not recover after a stop of emissions and thus recovery of CO2 (and hence climate) is slow. Further, we find that the terrestrial biosphere exhibits significant inertia and can continue to respond to climate changes decades after stabilisation of climate. This has serious implications for definitions of dangerous climate change based simply on stabilisation temperature as the absence of significant biome changes at the time of stabilisation does not preclude significant and potentially detrimental changes in subsequent decades. Assessments of targets for stabilising climate change often consider the impacts of different levels of global warming. These assessments usually consider impacts that would occur at the time of reaching a particular level of warming. However, global terrestrial ecosystems continue to respond over longer timescales. Here we introduce the concept of "committed ecosystem changes" analogous to climate warming commitments and committed sea-level rise due to thermal inertia. The true impact of climate change on ecosystems will not be revealed for many decades after stabilising temperatures. Further, we suggest that ecosystems may become committed to substantial damage long before any is observable. For example, significant loss of forest cover in Amazonia may become inevitable significantly below a global warming of 2K. When defining dangerous climate change, and forming policy to avoid it, such

  20. Extreme temperatures, foundation species, and abrupt ecosystem change: an example from an iconic seagrass ecosystem.

    PubMed

    Thomson, Jordan A; Burkholder, Derek A; Heithaus, Michael R; Fourqurean, James W; Fraser, Matthew W; Statton, John; Kendrick, Gary A

    2015-04-01

    Extreme climatic events can trigger abrupt and often lasting change in ecosystems via the reduction or elimination of foundation (i.e., habitat-forming) species. However, while the frequency/intensity of extreme events is predicted to increase under climate change, the impact of these events on many foundation species and the ecosystems they support remains poorly understood. Here, we use the iconic seagrass meadows of Shark Bay, Western Australia--a relatively pristine subtropical embayment whose dominant, canopy-forming seagrass, Amphibolis antarctica, is a temperate species growing near its low-latitude range limit--as a model system to investigate the impacts of extreme temperatures on ecosystems supported by thermally sensitive foundation species in a changing climate. Following an unprecedented marine heat wave in late summer 2010/11, A. antarctica experienced catastrophic (>90%) dieback in several regions of Shark Bay. Animal-borne video footage taken from the perspective of resident, seagrass-associated megafauna (sea turtles) revealed severe habitat degradation after the event compared with a decade earlier. This reduction in habitat quality corresponded with a decline in the health status of largely herbivorous green turtles (Chelonia mydas) in the 2 years following the heat wave, providing evidence of long-term, community-level impacts of the event. Based on these findings, and similar examples from diverse ecosystems, we argue that a generalized framework for assessing the vulnerability of ecosystems to abrupt change associated with the loss of foundation species is needed to accurately predict ecosystem trajectories in a changing climate. This includes seagrass meadows, which have received relatively little attention in this context. Novel research and monitoring methods, such as the analysis of habitat and environmental data from animal-borne video and data-logging systems, can make an important contribution to this framework. PMID:25145694

  1. Ecosystem vulnerability to climate change in the southeastern United States

    USGS Publications Warehouse

    Cartwright, Jennifer M.; Costanza, Jennifer

    2016-01-01

    Two recent investigations of climate-change vulnerability for 19 terrestrial, aquatic, riparian, and coastal ecosystems of the southeastern United States have identified a number of important considerations, including potential for changes in hydrology, disturbance regimes, and interspecies interactions. Complementary approaches using geospatial analysis and literature synthesis integrated information on ecosystem biogeography and biodiversity, climate projections, vegetation dynamics, soil and water characteristics, anthropogenic threats, conservation status, sea-level rise, and coastal flooding impacts. Across a diverse set of ecosystems—ranging in size from dozens of square meters to thousands of square kilometers—quantitative and qualitative assessments identified types of climate-change exposure, evaluated sensitivity, and explored potential adaptive capacity. These analyses highlighted key gaps in scientific understanding and suggested priorities for future research. Together, these studies help create a foundation for ecosystem-level analysis of climate-change vulnerability to support effective biodiversity conservation in the southeastern United States.

  2. Methods of Recording Rapid Wind Changes

    NASA Technical Reports Server (NTRS)

    Magnan, A

    1932-01-01

    The purpose of our research was to determine the rapid changes of air currents which impose varying stresses on the wings of airplanes. We attempted to express in figures the turbulence of the air, which perhaps plays some role in the behavior of airplanes in flight, as well as in the realization of certain methods of gliding flight. This is the reason which led us to conceive and develop the experimental equipment (hot-wire anemometer) described herein.

  3. A new way to study the changing Arctic ecosystem

    ScienceCinema

    Hubbard, Susan

    2013-05-29

    Berkeley Lab scientists Susan Hubbard and Margaret Torn discuss the proposed Next Generation Ecosystem Experiment, which is designed to answer one of the most urgent questions facing researchers today: How will a changing climate impact the Arctic, and how will this in turn impact the planet's climate? More info: http://newscenter.lbl.gov/feature-stories/2011/09/14/alaska-climate-change/

  4. A new way to study the changing Arctic ecosystem

    SciTech Connect

    Hubbard, Susan

    2011-01-01

    Berkeley Lab scientists Susan Hubbard and Margaret Torn discuss the proposed Next Generation Ecosystem Experiment, which is designed to answer one of the most urgent questions facing researchers today: How will a changing climate impact the Arctic, and how will this in turn impact the planet's climate? More info: http://newscenter.lbl.gov/feature-stories/2011/09/14/alaska-climate-change/

  5. The costs of climate change: ecosystem services and wildland fires

    EPA Science Inventory

    In this paper we use Habitat Equivalency Analysis (HEA) to monetize the avoided ecosystem services losses due to climate change-induced wildland fires in the U.S. Specifically, we use the U.S. Forest Service’s MC1 dynamic global vegetation model to forecast changes in wildland fi...

  6. Rapid environmental change during dynastic transitions in Yunnan Province, China

    NASA Astrophysics Data System (ADS)

    Hillman, Aubrey L.; Yu, JunQing; Abbott, Mark B.; Cooke, Colin A.; Bain, Daniel J.; Steinman, Byron A.

    2014-08-01

    Pollution and eutrophication of Chinese lakes are widely perceived to be 20th century phenomena. However, China has a long history of deforestation, agriculture, mineral resource extraction, and other anthropogenic activities that impact the environment. Here, we present a sediment record from Xing Yun Lake in the Yunnan Province of China that reveals significant alterations to the lake, its ecosystem, and its watershed beginning as early as 500 AD. A comprehensive suite of biogeochemical and isotopic proxies reveal several rapid transitions related to changes in agriculture and lake-level management that coincides with cultural and dynastic transitions. The deterioration of contemporary environmental conditions at Xing Yun arises from a long history of anthropogenic manipulation, eutrophication, and pollution of the lake and its watershed. This study highlights the importance of using historical records of industrial and agricultural activities, including landscape modification, in conjunction with records of climate change, to place present day environmental concerns into a long-term context.

  7. 30 years of change in water-limited ecosystems

    NASA Astrophysics Data System (ADS)

    Horion, S.; Fensholt, R.; Verbesselt, J.; Tagesson, T.; Grogan, K.; Ehammer, A.; Tian, F.

    2014-12-01

    Water availability limits plant growth and production in most terrestrial ecosystems. However these ecosystems do not show the same sensitivity to changes in precipitation. Water-limited ecosystems are defined here as ecosystems where rainfall is the dominant climate constraint to plant growth. Drought-prone and often characterized by increasing human pressure on land and natural resources, these regions are amongst the most vulnerable on Earth. Despite the many years of research, a clear understanding of changes in vegetation dynamics and species distribution, as well as related drivers, has not been reached yet. In this research we take advantage of the 30years time span offered by the GIMMS FAPAR3g dataset to investigate abrupt and gradual changes in Rain-Use Efficiency (RUE). Using the piece-wise regression method implemented in BFAST (Breaks For Additive Season and Trend) and BFAST01, a change type classification scheme is produced for water-limited ecosystems. Compared to classical non-parametric trend analysis, this approach allows detecting trend shifts during the study period. This global scale analysis revealed that for more than 50% of the cases no significant changes in RUE were registered between 1982 and 2011. Whereas when significant changes were registered, monotonic increase was the predominant type of changes. Large patches of reversing trends were also observed, notably in Asia (China, Kazakhstan), in the Sahelian region (Sudan, Ethiopia, Senegal), and in South America (Peru and Argentina). Even though reversing trends appear to be more frequently observed in regions with high land cover change dynamics, a comprehensive attribution of drivers for all recorded changes is still under discussion. Indeed the co-occurrence of global drivers (such as change in climate and in extreme events) and local drivers (such as land-cover changes) makes it a very delicate task.

  8. Exploring spatial change and gravity center movement for ecosystem services value using a spatially explicit ecosystem services value index and gravity model.

    PubMed

    He, Yingbin; Chen, Youqi; Tang, Huajun; Yao, Yanmin; Yang, Peng; Chen, Zhongxin

    2011-04-01

    Spatially explicit ecosystem services valuation and change is a newly developing area of research in the field of ecology. Using the Beijing region as a study area, the authors have developed a spatially explicit ecosystem services value index and implemented this to quantify and spatially differentiate ecosystem services value at 1-km grid resolution. A gravity model was developed to trace spatial change in the total ecosystem services value of the Beijing study area from a holistic point of view. Study results show that the total value of ecosystem services for the study area decreased by 19.75% during the period 1996-2006 (3,226.2739 US$×10(6) in 1996, 2,589.0321 US$×10(6) in 2006). However, 27.63% of the total area of the Beijing study area increased in ecosystem services value. Spatial differences in ecosystem services values for both 1996 and 2006 are very clear. The center of gravity of total ecosystem services value for the study area moved 32.28 km northwestward over the 10 years due to intensive human intervention taking place in southeast Beijing. The authors suggest that policy-makers should pay greater attention to ecological protection under conditions of rapid socio-economic development and increase the area of green belt in the southeastern part of Beijing. PMID:20556644

  9. [Dynamic changes of Ruoergai Plateau wetland ecosystem service value].

    PubMed

    Zhang, Xiao-Yun; Lü, Xian-Guo; Shen, Song-Ping

    2009-05-01

    Based on the satellite remote sensing data acquired in 1975 and 2006, and by using the assessment method of ecosystem service value, the dynamic changes of physical production value, gas regulation value, and water storage value of Ruoergai Plateau wetland ecosystem in 1975-2006 were studied. During study period, the total value of the three services decreased from 19.59 billion RMB Yuan to 12.38 billion Yuan RMB, among which, physical production value increased by 0.302 billion RMB Yuan, while the gas regulation and water storage value decreased by 7.507 billion RMB Yuan. The benefit from the increase of physical production was much less than the loss of ecosystem degradation. Overgrazing induced the biomass reduction and soil deterioration, resulting in the decline of Ruoergai Plateau wetland ecosystem service value and service capacity. PMID:19803173

  10. Assessing carbon dynamics in semiarid ecosystems : Balancing potential gains with potential large rapid losses

    SciTech Connect

    Breshears, D. D.; Ebinger, M. H.; Unkefer, P. J.

    2001-01-01

    Photosynthesis and respiration are the largest fluxes into and out of the biosphere (Molles 1999). Consequently, small changes in these fluxes can potentially produce large changes in the storage of carbon in the biosphere. Terrestrial carbon fluxes account for more than half of the carbon transferred between the atmosphere and the earth's surface (about 120 GigaTons/year), and current stores of carbon in terrestrial ecosystem are estimated at 2060 GigaTons. Increasing attention is being focused on the role of managing and sequestering carbon in the terrestrial biosphere as a means for addressing global climate change (IGBP, 1998; U.S. Department of Energy, 1999). Terrestrial ecosystems are widely recognized as a major biological scrubber for atmosphereic CO{sub 2} and their ability to finction as such can be increased significantly over the next 25 years through careful manipulation. The potential for terrestrial carbon gains has been the subject of much attention (Dixon et al., 1994; Masera et al. 1997; Cao and Woodward, 1998; DeLucia et al. 1999). In contrast to other strategies for reducing net carbon emissions, terrestrial sequestration has the potential for rapid implementation. Strategies that focus on soil carbon are likely to be effective because in addition to being a storage pool of carbon, soil carbon also improves site productivity through improving soil quality (e.g., water retention and nutrient availability). The carbon pool in soils is immense and highly dynamic. The flux of carbon into and out of soils is one of the largest uncertainties in the total mass balance of global carbon (NRC, 1999; La1 et al., 1998; Cambardella, 1998). Reducing these uncertainties is key to developing carbon sequestration strategies. Soil carbon pools have been greatly depleted over recent centuries, and there is potential to increase storage of carbon in these soils through effective land management. Whereas carbon in vegetation can be managed directly through land use

  11. Monitoring Change in Temperate Coniferous Forest Ecosystems

    NASA Technical Reports Server (NTRS)

    Williams, Darrel (Technical Monitor); Woodcock, Curtis E.

    2004-01-01

    The primary goal of this research was to improve monitoring of temperate forest change using remote sensing. In this context, change includes both clearing of forest due to effects such as fire, logging, or land conversion and forest growth and succession. The Landsat 7 ETM+ proved an extremely valuable research tool in this domain. The Landsat 7 program has generated an extremely valuable transformation in the land remote sensing community by making high quality images available for relatively low cost. In addition, the tremendous improvements in the acquisition strategy greatly improved the overall availability of remote sensing images. I believe that from an historical prespective, the Landsat 7 mission will be considered extremely important as the improved image availability will stimulate the use of multitemporal imagery at resolutions useful for local to regional mapping. Also, Landsat 7 has opened the way to global applications of remote sensing at spatial scales where important surface processes and change can be directly monitored. It has been a wonderful experience to have participated on the Landsat 7 Science Team. The research conducted under this project led to contributions in four general domains: I. Improved understanding of the information content of images as a function of spatial resolution; II. Monitoring Forest Change and Succession; III. Development and Integration of Advanced Analysis Methods; and IV. General support of the remote sensing of forests and environmental change. This report is organized according to these topics. This report does not attempt to provide the complete details of the research conducted with support from this grant. That level of detail is provided in the 16 peer reviewed journal articles, 7 book chapters and 5 conference proceedings papers published as part of this grant. This report attempts to explain how the various publications fit together to improve our understanding of how forests are changing and how to

  12. Changes in grassland ecosystem function due to extreme rainfall events: implications for responses to climate change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change driven by increasing atmospheric CO2 concentrations is causing measurable changes in precipitation patterns. Most climate change scenarios forecast continuing increases in extreme precipitation patterns for North American terrestrial ecosystems, manifest as larger precipitation event...

  13. Western Mountain Initiative: predicting ecosystem responses to climate change

    USGS Publications Warehouse

    Baron, Jill S.; Peterson, David L.; Wilson, J.T.

    2008-01-01

    Mountain ecosystems of the western United States provide irreplaceable goods and services such as water, timber, biodiversity, and recreational opportunities, but their responses to climatic changes are complex and not well understood. The Western Mountain Initiative (WMI), a collaboration between USGS and U.S. Forest Service scientists, catalyzes assessment and synthesis of the effects of disturbance and climate change across western mountain areas, focusing on national parks and surrounding national forests. The WMI takes an ecosystem approach to science, integrating research across science disciplines at scales ranging from field studies to global trends.

  14. Plant fitness in a rapidly changing world.

    PubMed

    Anderson, Jill T

    2016-04-01

    81 I. 81 II. 82 III. 84 IV. 84 V. 85 85 References 85 SUMMARY: Modern reliance on fossil fuels has ushered in extreme temperatures globally and abnormal precipitation patterns in many regions. Although the climate is changing rapidly, other agents of natural selection such as photoperiod remain constant. This decoupling of previously reliable environmental cues shifts adaptive landscapes, favors novel suites of traits and likely increases the extinction risk of local populations. Here, I examine the fitness consequences of changing climates. Meta-analyses demonstrate that simulated future climates depress viability and fecundity components of fitness for native plant species in the short term, which could reduce population growth rates. Contracting populations that cannot adapt or adjust plastically to new climates might not be capable of producing sufficient migrants to track changing conditions. PMID:26445400

  15. Buffer capacity, ecosystem feedbacks, and seawater chemistry under global change

    NASA Astrophysics Data System (ADS)

    Jury, C. P.; Thomas, F. I.; Atkinson, M. J.; Jokiel, P. L.; Onuma, M. A.; Kaku, N.; Toonen, R. J.

    2013-12-01

    Ocean acidification (OA) results in reduced seawater pH and aragonite saturation state (Ωarag), but also reduced seawater buffer capacity. As buffer capacity decreases, diel variation in seawater chemistry increases. However, a variety of ecosystem feedbacks can modulate changes in both average seawater chemistry and diel seawater chemistry variation. Here we model these effects for a coastal, reef flat ecosystem. We show that an increase in offshore pCO2 and temperature (to 900 μatm and +3°C) can increase diel pH variation by as much as a factor of 2.5 and can increase diel pCO2 variation by a factor of 4.6, depending on ecosystem feedbacks and seawater residence time. Importantly, these effects are different between day and night. With increasing seawater residence time and increasing feedback intensity, daytime seawater chemistry becomes more similar to present-day conditions while nighttime seawater chemistry becomes less similar to present-day conditions. Better constraining ecosystem feedbacks under global change will improve projections of coastal water chemistry, but this study shows the importance of considering changes in both average carbonate chemistry and diel chemistry variation for organisms and ecosystems. Further, we will discuss our recent work examining the effects of diel seawater chemistry variation on coral calcification rates.

  16. Interdependency of tropical marine ecosystems in response to climate change

    NASA Astrophysics Data System (ADS)

    Saunders, Megan I.; Leon, Javier X.; Callaghan, David P.; Roelfsema, Chris M.; Hamylton, Sarah; Brown, Christopher J.; Baldock, Tom; Golshani, Aliasghar; Phinn, Stuart R.; Lovelock, Catherine E.; Hoegh-Guldberg, Ove; Woodroffe, Colin D.; Mumby, Peter J.

    2014-08-01

    Ecosystems are linked within landscapes by the physical and biological processes they mediate. In such connected landscapes, the response of one ecosystem to climate change could have profound consequences for neighbouring systems. Here, we report the first quantitative predictions of interdependencies between ecosystems in response to climate change. In shallow tropical marine ecosystems, coral reefs shelter lagoons from incoming waves, allowing seagrass meadows to thrive. Deepening water over coral reefs from sea-level rise results in larger, more energetic waves traversing the reef into the lagoon, potentially generating hostile conditions for seagrass. However, growth of coral reef such that the relative water depth is maintained could mitigate negative effects of sea-level rise on seagrass. Parameterizing physical and biological models for Lizard Island, Great Barrier Reef, Australia, we find negative effects of sea-level rise on seagrass before the middle of this century given reasonable rates of reef growth. Rates of vertical carbonate accretion typical of modern reef flats (up to 3 mm yr-1) will probably be insufficient to maintain suitable conditions for reef lagoon seagrass under moderate to high greenhouse gas emissions scenarios by 2100. Accounting for interdependencies in ecosystem responses to climate change is challenging, but failure to do so results in inaccurate predictions of habitat extent in the future.

  17. Final Technical Report: Effects of Changing Water and Nitrogen Inputs on a Mojave Desert Ecosystem

    SciTech Connect

    Smith, Stanley, D.; Nowak, Robert S.; Fenstermaker, Lynn, F.; Young, Michael,H.

    2007-11-30

    In order to anticipate the effects of global change on ecosystem function, it is essential that predictive relationships be established linking ecosystem function to global change scenarios. The Mojave Desert is of considerable interest with respect to global change. It contains the driest habitats in North America, and thus most closely approximates the world’s great arid deserts. In order to examine the effects of climate and land use changes, in 2001 we established a long-term manipulative global change experiment, called the Mojave Global Change Facility. Manipulations in this study include the potential effects of (1) increased summer rainfall (75 mm over three discrete 25 mm events), (2) increased nitrogen deposition (10 and 40 kg ha-1), and (3) the disturbance of biological N-fixing crusts . Questions addressed under this grant shared the common hypothesis that plant and ecosystem performance will positively respond to the augmentation of the most limiting resources to plant growth in the Mojave Desert, e.g., water and nitrogen. Specific hypotheses include (1) increased summer rainfall will significantly increase plant production through an alleviation of moisture stress in the dry summer months, (2) N-deposition will increase plant production in this N-limited system, particularly in wet years or in concert with added summer rain, and (3) biological crust disturbance will gradually decrease bio-available N, with concomitant long-term reductions in photosynthesis and ANPP. Individual plant and ecosystem responses to global change may be regulated by biogeochemical processes and natural weather variability, and changes in plant and ecosystem processes may occur rapidly, may occur only after a time lag, or may not occur at all. During the first PER grant period, we observed changes in plant and ecosystem processes that would fall under each of these time-response intervals: plant and ecosystem processes responded rapidly to added summer rain, whereas most

  18. Urbanization, Climate Change, and Changes to Ecosystem Services in Coastal Areas

    NASA Astrophysics Data System (ADS)

    Sutton, P. C.; Costanza, R.; Roman, J.; Kubiszewski, I.

    2011-12-01

    We examine the history and status of ecosystem services in low-lying coastal areas (LLCA's), how they might change in the future in particular because of urbanization and wider environmental and social changes, and what the implications of these changes might be for the migration of humans. We synthesized information from a number of sources on the status and value of ecosystem services in LLCA's, including information about key ecosystems that are likely to be particularly vulnerable to environmental change. We created maps of ecosystem and human population changes in LLCA's and then estimated changes in ecosystem services. We developed four scenarios for future ecosystem and ecosystem services conditions in 2060, based on the four SRES (Special Report on Emissions Scenarios) scenarios with additional reference to the Millennium Ecosystem Assessment and the Great Transition Initiative scenarios. The two axes of the SRES scenarios are global vs. regional and material economy vs. environment foci. This allowed an assessment of the plausible range of future uncertainty about ecosystem services in LLCA's and the potential for changes in ecosystem services to drive human migration. Major findings include: 1) Coastal ecosystems are among the most productive on the planet. They provide more than 70% of total global ecosystem services; 2) At the same time, these systems are the most threatened by climate change, human settlement and potential coastward migration; 3) In the mid 1990's, approximately 25 million people were forced to leave their homelands due to the inability to secure a livelihood as ecosystem services declined; 4) In the coming decades, one estimate puts the number at 240-525 million people who may feel impelled to migrate due to loss of ecosystem services; 5) Risk factors for coastal populations include overexploitation of resources, including fisheries; destruction of mangroves, wetlands, and other natural infrastructure; increased storm activity and

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

    PubMed

    Larsen, Stefano; Muehlbauer, Jeffrey D; Marti, Eugenia

    2016-07-01

    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

  20. Estimating ecosystem service changes as a precursor to modeling

    EPA Science Inventory

    EPA's Future Midwestern Landscapes Study will project changes in ecosystem services (ES) for alternative future policy scenarios in the Midwestern U.S. Doing so for detailed landscapes over large spatial scales will require serial application of economic and ecological models. W...

  1. RESPONSE AND FEEDBACKS OF FOREST ECOSYSTEMS TO GLOBAL CLIMATE CHANGE

    EPA Science Inventory

    The accumulation of greenhouse gases in the atmosphere over the past century is projected to cause a warming of the Earth. Climate Change predictions vary by region and terrestrial biosphere response, and feedbacks will be ecosystem specific. Forests play a major role in the Eart...

  2. Fishing-induced life-history changes degrade and destabilize harvested ecosystems

    PubMed Central

    Kuparinen, Anna; Boit, Alice; Valdovinos, Fernanda S.; Lassaux, Hélène; Martinez, Neo D.

    2016-01-01

    Fishing is widely known to magnify fluctuations in targeted populations. These fluctuations are correlated with population shifts towards young, small, and more quickly maturing individuals. However, the existence and nature of the mechanistic basis for these correlations and their potential ecosystem impacts remain highly uncertain. Here, we elucidate this basis and associated impacts by showing how fishing can increase fluctuations in fishes and their ecosystem, particularly when coupled with decreasing body sizes and advancing maturation characteristic of the life-history changes induced by fishing. More specifically, using an empirically parameterized network model of a well-studied lake ecosystem, we show how fishing may both increase fluctuations in fish abundances and also, when accompanied by decreasing body size of adults, further decrease fish abundance and increase temporal variability of fishes’ food resources and their ecosystem. In contrast, advanced maturation has relatively little effect except to increase variability in juvenile populations. Our findings illustrate how different mechanisms underlying life-history changes that may arise as evolutionary responses to intensive, size-selective fishing can rapidly and continuously destabilize and degrade ecosystems even after fishing has ceased. This research helps better predict how life-history changes may reduce fishes’ resilience to fishing and ecosystems’ resistance to environmental variations. PMID:26915461

  3. Rapid Global Expansion of Invertebrate Fisheries: Trends, Drivers, and Ecosystem Effects

    PubMed Central

    Anderson, Sean C.; Mills Flemming, Joanna; Watson, Reg; Lotze, Heike K.

    2011-01-01

    Background Worldwide, finfish fisheries are receiving increasing assessment and regulation, slowly leading to more sustainable exploitation and rebuilding. In their wake, invertebrate fisheries are rapidly expanding with little scientific scrutiny despite increasing socio-economic importance. Methods and Findings We provide the first global evaluation of the trends, drivers, and population and ecosystem consequences of invertebrate fisheries based on a global catch database in combination with taxa-specific reviews. We also develop new methodologies to quantify temporal and spatial trends in resource status and fishery development. Since 1950, global invertebrate catches have increased 6-fold with 1.5 times more countries fishing and double the taxa reported. By 2004, 34% of invertebrate fisheries were over-exploited, collapsed, or closed. New fisheries have developed increasingly rapidly, with a decrease of 6 years (3 years) in time to peak from the 1950s to 1990s. Moreover, some fisheries have expanded further and further away from their driving market, encompassing a global fishery by the 1990s. 71% of taxa (53% of catches) are harvested with habitat-destructive gear, and many provide important ecosystem functions including habitat, filtration, and grazing. Conclusions Our findings suggest that invertebrate species, which form an important component of the basis of marine food webs, are increasingly exploited with limited stock and ecosystem-impact assessments, and enhanced management attention is needed to avoid negative consequences for ocean ecosystems and human well-being. PMID:21408090

  4. Final Technical Report: Effects of Changing Water and Nitrogen Inputs on a Mojave Desert Ecosystem

    SciTech Connect

    Smith, Stanley D.; Nowak, Robert S.

    2007-11-30

    Questions addressed under this grant shared the common hypothesis that plant and ecosystem performance will positively respond to the augmentation of the most limiting resources to plant growth in the Mojave Desert, e.g., water and nitrogen. Specific hypothesis include (1) increased summer rainfall will significantly increase plant production thorugh an alleviation of moisture stress in the dry summer months, (2) N-deposition will increase plan production in this N-limited system, particularly in wet years or in concert with added summer rain, and (3) biological crust disturbance will gradually decrease bio-available N, with concomitant long-term reductions in photosynthesis and ANPP. Individual plan and ecosystem responses to global change may be regulated by biogeochemical processes and natural weather variability, and changes in plant and ecosystem processes may occur rapidly, may occur only after a time lag, or may not occur at all. During the first PER grant period, we observed changes in plant and ecosystem processes that would fall under each of these time-response intervals: plant and ecosystem processes responded rapidly to added summer rain, whereas most processes responded slowly or in a lag fashion to N-deposition and with no significant response to crust disturbance. Therefore, the primary objectives of this renewal grant were to: (1) continue ongoing measurements of soil and plant parameters that assess primary treatment responses; (2) address the potential heterogeneity of soil properties and (3) initiate a new suite of measurements that will provide data necessary for scaling/modeling of whole-plot to ecosystem-level responses. Our experimental approach included soil plan-water interactions using TDR, neutron probe, and miniaturized soil matric potential and moisture sensors, plant ecophysiological and productivity responses to water and nitrogen treatments and remote sensing methodologies deployed on a radio control platform.

  5. Resilience in polar ecosystems: From drivers to impacts and changes

    NASA Astrophysics Data System (ADS)

    Bölter, Manfred; Müller, Felix

    2016-03-01

    The theory of resilience is increasing in applied ecosystem research and has become a valuable concept for analyzing relationships between natural environments and various stressors, e.g., global warming or direct human impacts. This concept offers opportunities to apply management strategies to different system levels and can provide insights into future ecosystem change. Polar systems are known to be ecologically sensitive to global and local impacts. Records of changes in polar environments, used as alarm signals by governmental and non-governmental institutions, are well documented in various reports. However, it remains difficult to define specific disturbance thresholds, only few methods allow an evaluation of the actual natural state of polar systems, its degree of modification they can accommodate before trophic systems change with severe damages. Some of the main drivers of system changes have been analyzed with respect to possible effects on system changes over different time scales. This paper reviews studies of polar ecosystems and their ability to cope with changes by assessing their resilience in response to human disturbances. Furthermore, we suggest that a customized framework (drivers, pressures, states, impacts, and responses (DPSIR)) should be applied to obtain an improved understanding of the interactions between the state of, and changes in, natural systems.

  6. Human activities change marine ecosystems by altering predation risk.

    PubMed

    Madin, Elizabeth M P; Dill, Lawrence M; Ridlon, April D; Heithaus, Michael R; Warner, Robert R

    2016-01-01

    In ocean ecosystems, many of the changes in predation risk - both increases and decreases - are human-induced. These changes are occurring at scales ranging from global to local and across variable temporal scales. Indirect, risk-based effects of human activity are known to be important in structuring some terrestrial ecosystems, but these impacts have largely been neglected in oceans. Here, we synthesize existing literature and data to explore multiple lines of evidence that collectively suggest diverse human activities are changing marine ecosystems, including carbon storage capacity, in myriad ways by altering predation risk. We provide novel, compelling evidence that at least one key human activity, overfishing, can lead to distinct, cascading risk effects in natural ecosystems whose magnitude exceeds that of presumed lethal effects and may account for previously unexplained findings. We further discuss the conservation implications of human-caused indirect risk effects. Finally, we provide a predictive framework for when human alterations of risk in oceans should lead to cascading effects and outline a prospectus for future research. Given the speed and extent with which human activities are altering marine risk landscapes, it is crucial that conservation and management policy considers the indirect effects of these activities in order to increase the likelihood of success and avoid unfortunate surprises. PMID:26448058

  7. Response of seafloor ecosystems to abrupt global climate change

    NASA Astrophysics Data System (ADS)

    Moffitt, Sarah E.; Hill, Tessa M.; Roopnarine, Peter D.; Kennett, James P.

    2015-04-01

    Anthropogenic climate change is predicted to decrease oceanic oxygen (O2) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. Thus far, this knowledge has been largely restricted to investigations using Foraminifera, with little being known about ecosystem-scale responses to abrupt, climate-forced deoxygenation. We here present high-resolution records based on the first comprehensive quantitative analysis, to our knowledge, of changes in marine metazoans (Mollusca, Echinodermata, Arthropoda, and Annelida; >5,400 fossils and trace fossils) in response to the global warming associated with the last glacial to interglacial episode. The molluscan archive is dominated by extremophile taxa, including those containing endosymbiotic sulfur-oxidizing bacteria (Lucinoma aequizonatum) and those that graze on filamentous sulfur-oxidizing benthic bacterial mats (Alia permodesta). This record, from 16,100 to 3,400 y ago, demonstrates that seafloor invertebrate communities are subject to major turnover in response to relatively minor inferred changes in oxygenation (>1.5 to <0.5 mLṡL-1 [O2]) associated with abrupt (<100 y) warming of the eastern Pacific. The biotic turnover and recovery events within the record expand known rates of marine biological recovery by an order of magnitude, from <100 to >1,000 y, and illustrate the crucial role of climate and oceanographic change in driving long-term successional changes in ocean ecosystems.

  8. Response of seafloor ecosystems to abrupt global climate change

    PubMed Central

    Moffitt, Sarah E.; Hill, Tessa M.; Roopnarine, Peter D.; Kennett, James P.

    2015-01-01

    Anthropogenic climate change is predicted to decrease oceanic oxygen (O2) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. Thus far, this knowledge has been largely restricted to investigations using Foraminifera, with little being known about ecosystem-scale responses to abrupt, climate-forced deoxygenation. We here present high-resolution records based on the first comprehensive quantitative analysis, to our knowledge, of changes in marine metazoans (Mollusca, Echinodermata, Arthropoda, and Annelida; >5,400 fossils and trace fossils) in response to the global warming associated with the last glacial to interglacial episode. The molluscan archive is dominated by extremophile taxa, including those containing endosymbiotic sulfur-oxidizing bacteria (Lucinoma aequizonatum) and those that graze on filamentous sulfur-oxidizing benthic bacterial mats (Alia permodesta). This record, from 16,100 to 3,400 y ago, demonstrates that seafloor invertebrate communities are subject to major turnover in response to relatively minor inferred changes in oxygenation (>1.5 to <0.5 mL⋅L−1 [O2]) associated with abrupt (<100 y) warming of the eastern Pacific. The biotic turnover and recovery events within the record expand known rates of marine biological recovery by an order of magnitude, from <100 to >1,000 y, and illustrate the crucial role of climate and oceanographic change in driving long-term successional changes in ocean ecosystems. PMID:25825727

  9. Response of seafloor ecosystems to abrupt global climate change.

    PubMed

    Moffitt, Sarah E; Hill, Tessa M; Roopnarine, Peter D; Kennett, James P

    2015-04-14

    Anthropogenic climate change is predicted to decrease oceanic oxygen (O2) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. Thus far, this knowledge has been largely restricted to investigations using Foraminifera, with little being known about ecosystem-scale responses to abrupt, climate-forced deoxygenation. We here present high-resolution records based on the first comprehensive quantitative analysis, to our knowledge, of changes in marine metazoans (Mollusca, Echinodermata, Arthropoda, and Annelida; >5,400 fossils and trace fossils) in response to the global warming associated with the last glacial to interglacial episode. The molluscan archive is dominated by extremophile taxa, including those containing endosymbiotic sulfur-oxidizing bacteria (Lucinoma aequizonatum) and those that graze on filamentous sulfur-oxidizing benthic bacterial mats (Alia permodesta). This record, from 16,100 to 3,400 y ago, demonstrates that seafloor invertebrate communities are subject to major turnover in response to relatively minor inferred changes in oxygenation (>1.5 to <0.5 mL⋅L(-1) [O2]) associated with abrupt (<100 y) warming of the eastern Pacific. The biotic turnover and recovery events within the record expand known rates of marine biological recovery by an order of magnitude, from <100 to >1,000 y, and illustrate the crucial role of climate and oceanographic change in driving long-term successional changes in ocean ecosystems. PMID:25825727

  10. Ecosystem change in the southern Benguela and the underlying processes

    NASA Astrophysics Data System (ADS)

    Blamey, Laura K.; Shannon, Lynne J.; Bolton, John J.; Crawford, Robert J. M.; Dufois, Francois; Evers-King, Hayley; Griffiths, Charles L.; Hutchings, Laurence; Jarre, Astrid; Rouault, Mathieu; Watermeyer, Katherine E.; Winker, Henning

    2015-04-01

    Overfishing and human-induced climate change are putting severe pressure on marine ecosystems. In the southern Benguela, most of South Africa's commercial fisheries have a long history of exploitation and this, coupled with spatio-temporal changes in key species over the last three decades has severely impacted some of South Africa's fisheries and ecosystems. This review summarizes these spatio-temporal changes and investigates possible drivers thereof. It incorporates both past and current research, with a large portion of the latter having formed part of the University of Cape Town's Ma-Re BASICS (Marine Research in the Benguela and Agulhas Systems for supporting Interdisciplinary Climate-change Science) 2010-2013 program. Almost all described changes involve a temporal decline or a spatial shift in species. Fishing seems to have played a role in many of the observed stock declines, for example through geographically disproportionate catches in relation to stock distribution. In some cases, changes in the physical environment seem to have played an additional role, e.g., rock lobsters on the west coast have been affected by fishing as well as changes in the physical environment. In almost all cases these changes have taken place since the 1980s/1990s, except for one or two resources, which have experienced declines since at least the mid 20th century. Spatial shifts in species have either involved an eastward expansion of cool-water species, including kelps, rock lobster and pelagic fish, or a retraction of warm-water species such as the brown mussel, suggesting a cooling of inshore waters along the south-west coast since the 1980s. This suggested cooling is revealed in ocean temperature (SST Pathfinder), wind and upwelling data for the Cape Peninsula and south-west coast region during the same period. The absence or inconsistency of long-term data is problematic when trying to identify drivers of ecosystem change, and actual ecosystem change itself. We discuss

  11. Economic development and coastal ecosystem change in China.

    PubMed

    He, Qiang; Bertness, Mark D; Bruno, John F; Li, Bo; Chen, Guoqian; Coverdale, Tyler C; Altieri, Andrew H; Bai, Junhong; Sun, Tao; Pennings, Steven C; Liu, Jianguo; Ehrlich, Paul R; Cui, Baoshan

    2014-01-01

    Despite their value, coastal ecosystems are globally threatened by anthropogenic impacts, yet how these impacts are driven by economic development is not well understood. We compiled a multifaceted dataset to quantify coastal trends and examine the role of economic growth in China's coastal degradation since the 1950s. Although China's coastal population growth did not change following the 1978 economic reforms, its coastal economy increased by orders of magnitude. All 15 coastal human impacts examined increased over time, especially after the reforms. Econometric analysis revealed positive relationships between most impacts and GDP across temporal and spatial scales, often lacking dropping thresholds. These relationships generally held when influences of population growth were addressed by analyzing per capita impacts, and when population density was included as explanatory variables. Historical trends in physical and biotic indicators showed that China's coastal ecosystems changed little or slowly between the 1950s and 1978, but have degraded at accelerated rates since 1978. Thus economic growth has been the cause of accelerating human damage to China's coastal ecosystems. China's GDP per capita remains very low. Without strict conservation efforts, continuing economic growth will further degrade China's coastal ecosystems. PMID:25104138

  12. Economic development and coastal ecosystem change in China

    PubMed Central

    He, Qiang; Bertness, Mark D.; Bruno, John F.; Li, Bo; Chen, Guoqian; Coverdale, Tyler C.; Altieri, Andrew H.; Bai, Junhong; Sun, Tao; Pennings, Steven C.; Liu, Jianguo; Ehrlich, Paul R.; Cui, Baoshan

    2014-01-01

    Despite their value, coastal ecosystems are globally threatened by anthropogenic impacts, yet how these impacts are driven by economic development is not well understood. We compiled a multifaceted dataset to quantify coastal trends and examine the role of economic growth in China's coastal degradation since the 1950s. Although China's coastal population growth did not change following the 1978 economic reforms, its coastal economy increased by orders of magnitude. All 15 coastal human impacts examined increased over time, especially after the reforms. Econometric analysis revealed positive relationships between most impacts and GDP across temporal and spatial scales, often lacking dropping thresholds. These relationships generally held when influences of population growth were addressed by analyzing per capita impacts, and when population density was included as explanatory variables. Historical trends in physical and biotic indicators showed that China's coastal ecosystems changed little or slowly between the 1950s and 1978, but have degraded at accelerated rates since 1978. Thus economic growth has been the cause of accelerating human damage to China's coastal ecosystems. China's GDP per capita remains very low. Without strict conservation efforts, continuing economic growth will further degrade China's coastal ecosystems. PMID:25104138

  13. Ecosystem and Food Security in a Changing Climate

    NASA Astrophysics Data System (ADS)

    Field, C. B.

    2011-12-01

    Observed and projected impacts of climate change for ecosystem and food security tend to appear as changes in the risk of both desirable and undesirable outcomes. As a consequence, it is useful to frame the challenge of adaptation to a changing climate as a problem in risk management. For some kinds of impacts, the risks are relatively well characterized. For others, they are poorly known. Especially for the cases where the risks are poorly known, effective adaptation will need to consider approaches that build dynamic portfolios of options, based on learning from experience. Effective adaptation approaches also need to consider the risks of threshold-type responses, where opportunities for gradual adaptation based on learning may be limited. Finally, effective adaptation should build on the understanding that negative impacts on ecosystems and food security often result from extreme events, where a link to climate change may be unclear now and far into the future. Ecosystem and food security impacts that potentially require adaptation to a changing climate vary from region to region and interact strongly with actions not related to climate. In many ecosystems, climate change shifts the risk profile to increase risks of wildfire and biological invasions. Higher order risks from factors like pests and pathogens remain difficult to quantify. For food security, observational evidence highlights threshold-like behavior to high temperature in yields of a number of crops. But the risks to food security may be much broader, encompassing risks to availability of irrigation, degradation of topsoil, and challenges of storage and distribution. A risk management approach facilitates consideration of all these challenges with a unified framework.

  14. How Does Climate Change Affect the Bering Sea Ecosystem?

    NASA Astrophysics Data System (ADS)

    Sigler, Michael F.; Harvey, H. Rodger; Ashjian, Carin J.; Lomas, Michael W.; Napp, Jeffrey M.; Stabeno, Phyllis J.; Van Pelt, Thomas I.

    2010-11-01

    The Bering Sea is one of the most productive marine ecosystems in the world, sustaining nearly half of U.S. annual commercial fish catches and providing food and cultural value to thousands of coastal and island residents. Fish and crab are abundant in the Bering Sea; whales, seals, and seabirds migrate there every year. In winter, the topography, latitude, atmosphere, and ocean circulation combine to produce a sea ice advance in the Bering Sea unmatched elsewhere in the Northern Hemisphere, and in spring the retreating ice; longer daylight hours; and nutrient-rich, deep-ocean waters forced up onto the broad continental shelf result in intense marine productivity (Figure 1). This seasonal ice cover is a major driver of Bering Sea ecology, making this ecosystem particularly sensitive to changes in climate. Predicted changes in ice cover in the coming decades have intensified concern about the future of this economically and culturally important region. In response, the North Pacific Research Board (NPRB) and the U.S. National Science Foundation (NSF) entered into a partnership in 2007 to support the Bering Sea Project, a comprehensive $52 million investigation to understand how climate change is affecting the Bering Sea ecosystem, ranging from lower trophic levels (e.g., plankton) to fish, seabirds, marine mammals, and, ultimately, humans. The project integrates two research programs, the NSF Bering Ecosystem Study (BEST) and the NPRB Bering Sea Integrated Ecosystem Research Program (BSIERP), with substantial in-kind contributions from the U.S. National Oceanic and Atmospheric Administration (NOAA) and the U.S. Fish and Wildlife Service.

  15. Non-linearity dynamics in ecosystem response to climate change: Case studies and policy implications

    USGS Publications Warehouse

    Burkett, V.R.; Wilcox, D.A.; Stottlemyer, R.; Barrow, W.; Fagre, D.; Baron, J.; Nielsen, J.L.; Allen, C.D.; Peterson, D.L.; Ruggerone, G.; Doyle, T.

    2005-01-01

    Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that cascade among systems, precluding accurate modeling and prediction of system response to climate change. Ten case studies from North America illustrate how changes in climate cna lead to rapid, threshold-type responses within ecological communities; the case studies also highlight the role of human activities that alter the rate or direction of system response to climate change. Understanding and anticipating nonlinear dynamics are important aspects of adaptation planning since responses of biological resources to changes in the physical climate system are not necessarily proportional and sometimes, as in the case of complex ecological systems, inherently nonlinear.

  16. Nonlinear dynamics in ecosystem response to climatic change: Case studies and policy implications

    USGS Publications Warehouse

    Burkett, Virginia R.; Wilcox, Douglas A.; Stottlemyer, Robert; Barrow, Wylie; Fagre, Dan; Baron, Jill; Price, Jeff; Nielsen, Jennifer L.; Allen, Craig D.; Peterson, David L.; Ruggerone, Greg; Doyle, Thomas

    2005-01-01

    Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that cascade among systems, precluding accurate modeling and prediction of system response to climate change. Ten case studies from North America illustrate how changes in climate can lead to rapid, threshold-type responses within ecological communities; the case studies also highlight the role of human activities that alter the rate or direction of system response to climate change. Understanding and anticipating nonlinear dynamics are important aspects of adaptation planning since responses of biological resources to changes in the physical climate system are not necessarily proportional and sometimes, as in the case of complex ecological systems, inherently nonlinear.

  17. The Longterm Effects of Climate Change in European Shrubland Ecosystems

    NASA Astrophysics Data System (ADS)

    Emmett, B.; Sowerby, A.; Smith, A.; EU Increase-infrastructure Project Team

    2011-12-01

    Shrublands constitute significant and important parts of European landscapes providing a large number of important ecosystem services. Biogeochemical cycles in these ecosystems have gained little attention relative to forests and grassland systems. As climate change progresses the potential feedback from the biosphere to the atmosphere through changes in above and below-ground structure and functioning will become increasingly important. A series of replicate long term climate change experiments have been running for ca. 10 years in contrasting shrubland types across Europe to quantify; (a) the potential changes in carbon sequestration, GHG emissions and nutrient cycling, (b) the links to above and below-ground biodiversity, and (c) implications for water quality, in response to warming and repeated summer drought. Results indicate a relatively high rate of below-ground carbon allocation compared to forest systems and the importance of modifying factors such as past and current management, atmospheric deposition and soil type in determining resilience to change. Unexpectedly, sustained reduction in soil moisture over winter (between drought periods and despite major winter rainfall) was observed in the repeated summer drought treatment, along with a reduction in the maximum water-holding capacity attained. The persistent reduction in soil moisture throughout the year resulted in a year-round increase in soil respiration flux, a response that accelerated over time to 40% above control levels in the hydric, organic-rich UK system. As above-ground biomass, litter production and diversity was remarkably stable, changes in soil fungal communities and soil physical structure appear to be critical in driving changes in soil carbon fluxes in this organic-rich site. Current ecosystem models may under-estimate potential changes in carbon loss in response to climate change if changes in soil biological and physical properties are not included.

  18. What is Novel About Novel Ecosystems: Managing Change in an Ever-Changing World.

    PubMed

    Truitt, Amy M; Granek, Elise F; Duveneck, Matthew J; Goldsmith, Kaitlin A; Jordan, Meredith P; Yazzie, Kimberly C

    2015-06-01

    Influenced by natural climatic, geological, and evolutionary changes, landscapes and the ecosystems within are continuously changing. In addition to these natural pressures, anthropogenic drivers have increasingly influenced ecosystems. Whether affected by natural or anthropogenic processes, ecosystems, ecological communities, and ecosystem functioning are dynamic and can lead to "novel" or "emerging" ecosystems. Current literature identifies several definitions of these ecosystems but lacks an unambiguous definition and framework for categorizing what constitutes a novel ecosystem and for informing decisions around best management practices. Here we explore the various definitions used for novel ecosystems, present an unambiguous definition, and propose a framework for identifying the most appropriate management option. We identify and discuss three approaches for managing novel ecosystems: managing against, tolerating, and managing for these systems, and we provide real-world examples of each approach. We suggest that this framework will allow managers to make thoughtful decisions about which strategy is most appropriate for each unique situation, to determine whether the strategy is working, and to facilitate decision-making when it is time to modify the management approach. PMID:25822888

  19. What is Novel About Novel Ecosystems: Managing Change in an Ever-Changing World

    NASA Astrophysics Data System (ADS)

    Truitt, Amy M.; Granek, Elise F.; Duveneck, Matthew J.; Goldsmith, Kaitlin A.; Jordan, Meredith P.; Yazzie, Kimberly C.

    2015-06-01

    Influenced by natural climatic, geological, and evolutionary changes, landscapes and the ecosystems within are continuously changing. In addition to these natural pressures, anthropogenic drivers have increasingly influenced ecosystems. Whether affected by natural or anthropogenic processes, ecosystems, ecological communities, and ecosystem functioning are dynamic and can lead to "novel" or "emerging" ecosystems. Current literature identifies several definitions of these ecosystems but lacks an unambiguous definition and framework for categorizing what constitutes a novel ecosystem and for informing decisions around best management practices. Here we explore the various definitions used for novel ecosystems, present an unambiguous definition, and propose a framework for identifying the most appropriate management option. We identify and discuss three approaches for managing novel ecosystems: managing against, tolerating, and managing for these systems, and we provide real-world examples of each approach. We suggest that this framework will allow managers to make thoughtful decisions about which strategy is most appropriate for each unique situation, to determine whether the strategy is working, and to facilitate decision-making when it is time to modify the management approach.

  20. Projected future climate change and Baltic Sea ecosystem management

    NASA Astrophysics Data System (ADS)

    Andersson, Agneta

    2015-04-01

    Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4oC warming and 50-80% decreasing ice cover by 2100. Precipitation may increase ~30% in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants. Salinity will decrease by about 2 units. Coupled physical-biogeochemical models indicate that in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favoured by AOM while phytoplankton may become hampered. More trophic levels in the food web will increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider effects of climate change on the ecosystem dynamics and functions, as well as effects of anthrophogenic nutrient and pollutant load. Monitoring should have a holistic approach and encompass both autotrophic (phytoplankton) and heterotrophic (e.g. bacterial) processes.

  1. Molecular changes of DOM cycling in forest ecosystem

    NASA Astrophysics Data System (ADS)

    Hara, M.; Ohashi, M.; Piirainen, S.; Kortelainen, P.; Finer, L.; Kumagai, T.; Takahashi, K.; Sugiyama, Y.

    2011-12-01

    Fresh water is essential for sustaining all the life on the earth. Most of the fresh water available for human is stored in forest ecosystem in the forms of soil and ground water. Therefore, the chemical compositions of fresh water could be controlled by the forest ecosystem. Dissolved Organic Matter (DOM) is one of the main dissolved components of water. Since it controls the cycling processes of both organic and inorganic matters in water by variety of physical, chemical, and biochemical interactions, chatacterization of DOM in both qualitatively and quantitatively is very important. However, molecular-level study in DOM has been behind due to technological difficulties. Over the past years, high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) which enables us to identify individual molecular species of DOM had been hugely developed and brought radical changes to the analysis of many different substances in molecular level. The purpose of this study is to observe the cycling and alteration process of DOM in the forest ecosystem substantially using FT-ICR MS. We analyzed DOM samples by FT-ICR MS to determine the molecular-level characteristics of DOM. We also analyzed dissolved organic carbon (DOC) and characteristics of fluorescence spectra to elucidate the bulk characteristics of DOM in the forest ecosystem. In forest ecosystem, DOC increased from bulk deposition (1.0~3.3 mgC/L) and throughfall (0.8~3.6 mgC/L) to soil water of the A- (4.7~28.6 mgC/L) and B-horizon (4.5~29.2 mgC/L). DOC decreased as the water percolated through the soil deeper to ground water (0.3~1.7 mgC/L). In the whole forest ecosystem, fluorescence spectra showed strong humic-like fluorescence peaks rather than protein-like peaks. Each sample's result of FT-ICR MS including bulk deposition, throughfall, soil waters in different depths, and groundwater showed different molecular characteristics between one another. These results suggest that DOM in water is

  2. Potential Effects of Climate Change on Aquatic Ecosystems of the Great Plains of North America

    NASA Astrophysics Data System (ADS)

    Covich, A. P.; Fritz, S. C.; Lamb, P. J.; Marzolf, R. D.; Matthews, W. J.; Poiani, K. A.; Prepas, E. E.; Richman, M. B.; Winter, T. C.

    1997-06-01

    The Great Plains landscape is less topographically complex than most other regions within North America, but diverse aquatic ecosystems, such as playas, pothole lakes, ox-bow lakes, springs, groundwater aquifers, intermittent and ephemeral streams, as well as large rivers and wetlands, are highly dynamic and responsive to extreme climatic fluctuations. We review the evidence for climatic change that demonstrates the historical importance of extremes in north-south differences in summer temperatures and east-west differences in aridity across four large subregions. These physical driving forces alter density stratification, deoxygenation, decomposition and salinity. Biotic community composition and associated ecosystem processes of productivity and nutrient cycling respond rapidly to these climatically driven dynamics. Ecosystem processes also respond to cultural effects such as dams and diversions of water for irrigation, waste dilution and urban demands for drinking water and industrial uses. Distinguishing climatic from cultural effects in future models of aquatic ecosystem functioning will require more refinement in both climatic and economic forecasting. There is a need, for example, to predict how long-term climatic forecasts (based on both ENSO and global warming simulations) relate to the permanence and productivity of shallow water ecosystems. Aquatic ecologists, hydrologists, climatologists and geographers have much to discuss regarding the synthesis of available data and the design of future interdisciplinary research.

  3. Potential effects of climate change on aquatic ecosystems of the Great Plains of North America

    USGS Publications Warehouse

    Covich, A.P.; Fritz, S.C.; Lamb, P.J.; Marzolf, R.D.; Matthews, W.J.; Poiani, K.A.; Prepas, E.E.; Richman, M.B.; Winter, T.C.

    1997-01-01

    The Great Plains landscape is less topographically complex than most other regions within North America, but diverse aquatic ecosystems, such as playas, pothole lakes, ox-bow lakes, springs, groundwater aquifers, intermittent and ephemeral streams, as well as large rivers and wetlands, are highly dynamic and responsive to extreme climatic fluctuations. We review the evidence for climatic change that demonstrates the historical importance of extremes in north-south differences in summer temperatures and east-west differences in aridity across four large subregions. These physical driving forces alter density stratification, deoxygenation, decomposition and salinity. Biotic community composition and associated ecosystem processes of productivity and nutrient cycling respond rapidly to these climatically driven dynamics. Ecosystem processes also respond to cultural effects such as dams and diversions of water for irrigation, waste dilution and urban demands for drinking water and industrial uses. Distinguishing climatic from cultural effects in future models of aquatic ecosystem functioning will require more refinement in both climatic and economic forecasting. There is a need, for example, to predict how long-term climatic forecasts (based on both ENSO and global warming simulations) relate to the permanence and productivity of shallow water ecosystems. Aquatic ecologists, hydrologists, climatologists and geographers have much to discuss regarding the synthesis of available data and the design of future interdisciplinary research. ?? 1997 by John Wiley & Sons, Ltd.

  4. Alaska's Arctic Landscapes: Land cover, Monitoring and Assessing Arctic Ecosystems and their Change Agents

    NASA Astrophysics Data System (ADS)

    Guyer, P. S.

    2013-12-01

    The challenge for agencies who manage the 89,000 square miles constituting Alaska's arctic ecoregion is in understanding what, where and to what extent important ecosystems exist. How do each of these ecosystems function? What are the key components of these ecosystems? How are they affected by the changing climate, fire, permafrost changes and development? Answers to these management questions come not from one specific project or program but from a series of data gathering efforts. Landcover mapping of Alaska's arctic using satellite imagery began in the mid 1990's. Over the past three years the land cover has been updated using additional ground truth data and the most up to date image processing software. In 2012, the updated map was used for the first time to select sites for an inventory and monitoring pilot project. The project established a baseline of information for long-term monitoring of regional ecological components. That same year the Bureau of Land Management began a Rapid Ecoregional Assessment across the North Slope of Alaska. This effort will utilize the known environments established by the land cover map and will model the effects of climate change, fire, permafrost change and development. The assessment and modeling effort will show how the effect of these change agents would shape long term conservation, restoration and development efforts. These interactions together will advance the understanding of the arctic ecoregion its values, processes and functions and how the agents of change will shape the future.

  5. The impact of climate change on coastal ecosystems: chapter 6

    USGS Publications Warehouse

    Burkett, Virginia; Woodroffe, Colin D.; Nicholls, Robert J.; Forbes, Donald L.

    2014-01-01

    In this chapter we stress two important features of coasts and coastal ecosystems. First, these are dynamic systems which continually undergo adjustments, especially through erosion and re-deposition, in response to a range of processes. Many coastal ecosystems adjust naturally at a range of time scales and their potential for response is examined partly by reconstructing how such systems have coped with natural changes of climate and sea level in the geological past. Second, coasts have changed profoundly through the 20th Century due to the impacts of human development (such as urbanisation, port and industrial expansion, shore protection, and the draining and conversion of coastal wetlands), with these development-related drivers closely linked to a growing global population and economy. It remains a challenge to isolate the impacts of climate change and sea-level rise from either the natural trajectory of shoreline change, or the accelerated pathway resulting from other human-related stressors. There exists a danger of overstating the importance of climate change, or overlooking significant interactions of climate change with other drivers.

  6. Climate change on arctic environment, ecosystem services and society (CLICHE)

    NASA Astrophysics Data System (ADS)

    Weckström, J.; Korhola, A.; Väliranta, M.; Seppä, H.; Luoto, M.; Tuittila, E.-S.; Leppäranta, M.; Kahilainen, K.; Saarinen, J.; Heikkinen, H.

    2012-04-01

    The predicted climate warming has raised many questions and concerns about its impacts on the environment and society. As a respond to the need of holistic studies comprising both of these areas, The Academy of Finland launched The Finnish Research Programme on Climate Change (FICCA 2011-2014) in spring 2010 with the main aim to focus on the interaction between the environment and society. Ultimately 11 national consortium projects were funded (total budget 12 million EUR). Here we shortly present the main objectives of the largest consortium project "Climate change on arctic environment, ecosystem services and society" (CLICHE). The CLICHE consortium comprises eight interrelated work packages (treeline, diversity, peatlands, snow, lakes, fish, tourism, and traditional livelihoods), each led by a prominent research group and a team leader. The research consortium has three main overall objectives: 1) Investigate, map and model the past, present and future climate change-induced changes in central ecosystems of the European Arctic with unprecedented precision 2) Deepen our understanding of the basic principles of ecosystem and social resilience and dynamics; identify key taxa, structures or processes that clearly indicate impending or realised global change through their loss, occurrence or behaviour, using analogues from the past (e.g. Holocene Thermal Maximum, Medieval Warm Period), experiments, observations and models 3) Develop adaptation and mitigation strategies to minimize the adverse effects of climate change on local communities, traditional livelihoods, fisheries, and tourism industry, and promote sustainable development of local community structures and enhance the quality of life of local human populations. As the project has started only recently no final results are available yet. However, the fieldwork as well as the co-operation between the research teams has thus far been very successful. Thus, the expectations for the final outcome of the project

  7. Benthic Foraminifera in the Changing Ecosystem of Long Island Sound

    NASA Astrophysics Data System (ADS)

    Thaler, B.; Thomas, E.; Varekamp, J. C.

    2004-05-01

    Long Island Sound (LIS) is an estuary in a heavily urbanized region; Long Island lies to its South, New York City (NYC) to its West and Connecticut to its North. The Connecticut River contributes >70% of the fresh water influx. LIS has a narrow opening to the West (into East River), but exchange with the ocean occurs dominantly at its eastern end, resulting in an east-west gradient in salinity. An east-west gradient is also present in indicators of anthropogenic contamination in the surface sediments (e.g., trace metals) because western LIS is close to the major source of anthropogenic input (NYC). In addition, bottom currents focus fine-grained, contaminant-loaded sediments there. Since the early 1970's western LIS and parts of central LIS have suffered summer hypoxia, probably as a result of increased algal growth caused by anthropogenic nitrogen input. Benthic foraminifera are eukaryote heterotrophic organisms with a calcareous or agglutinated test. We investigated changes in their populations over time in about 2m-long gravity cores in westernmost (WLIS75GGC1; 73o 40'W, 40o 52'N, 19m waterdepth) and coastal central LIS (B1GGC1; 73o 4'W, 41o 10'N, 8m water depth), to document environmental changes over the last millennium, including the time of European settlement and the industrial revolution and population increase. An age model was derived from metal pollution records and 14C dating. Before European settlement, the low-diversity benthic faunas in core B1GGC1, at a depth within the zone of light penetration, were dominated by Elphidium excavatum, a species feeding on living diatoms. In western LIS (below the zone of light penetration) this species was less abundant and Elphidium incertum and Buccella frigida were common. In both cores, the absolute abundance of benthic foraminifera and the relative abundance of Elphidium excavatum increased in the early 1800's, coinciding with a time of rapid increase in human population around LIS and slightly before an

  8. Climate Extremes and Land-Use Change: Effects on Ecosystem Processes and Services

    NASA Astrophysics Data System (ADS)

    Bahn, Michael; Erb, Karlheinz; Hasibeder, Roland; Mayr, Stefan; Niedertscheider, Maria; Oberhuber, Walter; Tappeiner, Ulrike; Tasser, Erich; Viovy, Nicolas; Wieser, Gerhard

    2016-04-01

    Extreme climatic events, in particular droughts and heatwaves, have significant impacts on ecosystem carbon and water cycles and a range of related ecosystem services. It is expected that in the coming decades the return intervals and severities of extreme droughts will increase substantially and may result in the passing of thresholds of ecosystem functioning, potentially causing legacy effects, which are so far poorly understood. Observational evidence suggests that different land cover types (forest, grassland) are differently influenced by extreme drought, but there is a lack of knowledge whether and how future, increasingly severe climate extremes will affect their concurrent and lagged responses, as well as land-use decisions determining future shifts in land cover. The ClimLUC project aims to understand how extreme summer drought affects carbon and water dynamics of mountain ecosystems under different land uses, and to analyse implications for ecosystem service provisioning. Overall, we hypothesize that land-use change alters the effects of extreme summer drought on ecosystem processes and the related services, grassland responding more rapidly and strongly but being more resilient to extreme drought than forest. To address the aims and hypotheses, we will 1) test experimentally how (a) a managed, (b) an abandoned mountain grassland and (c) an adjacent subalpine forest respond to a progressive extreme drought and will analyse threshold responses of carbon and water dynamics and their implications for ecosystem services (timber and fodder production, carbon sequestration, water provisioning); 2) quantify carry-over effects of the extreme event on ecosystem processes and services; 3) project and attribute future carbon and water cycle responses to extreme drought and related socio-economic changes, based on a process-based dynamic general vegetation model; 4) analyse the interrelation between land-use changes and the occurrence and severity of past and future

  9. Could Ecosystem Change over Amazonia Influence Climate over North America?

    NASA Astrophysics Data System (ADS)

    Fu, R.; Arias Gomez, P. A.; Wang, H.

    2014-12-01

    Earth system model experiments suggest that ecosystem changes in the Northern Hemisphere could influence climate over the Southern Hemisphere, or vice versa. In reality, whether an ecosystem change could have a detectable influence on climate variability in remote regions is not clear. Direct validation of such an influence based on available climate records is not feasible largely because we cannot isolate the influences of ecosystems from more dominant sources of climate variability from ocean and atmosphere. However, our observational analysis suggests that the variability of wet season onset over the Amazonia, which is significantly influenced by evapotranspiration of the rainforest, could influence the demise of the North American monsoon. Such a remote influence appears to be carried out by the influence of the Amazonia rainfall on the cross-equatorial flow and latitudinal propagation of the atmospheric waves, which in turn, influence wind and moisture transport over the North American monsoon region. These results suggest that perhaps the future reduction of evapotranspiration due to CO2 fertilization and large-scale land use over the Amazonia will not only delay the wet season onset over this region, but also impact the demise of the North American monsoon.

  10. Proceedings of the global climate change and freshwater ecosystems

    SciTech Connect

    Firth, P.; Fisher, S.G.

    1992-01-01

    This book discusses global climate change which is a certainty. The Earth's climate has never remained static for long and the prospect for human-accelerated climate change in the near future appears likely. Freshwater systems are intimately connected to climate in several ways. They may influence, or even drive, global atmospheric processes affecting climate (e.g., biogenic gas emissions from freshwater wetlands). They may be sensitive early indicators of climate change because they integrate the atmospheric and terrestrial events occurring in their catchments. And, of course, they will be affected by climate change. Freshwater hydrological processes, freshwater resources, and freshwater ecosystems have historically responded to climatic shifts and we fully expect that they will continue to do so. Climate-induced changes may include altered water temperatures, runoff, nutrient flux, discharge, flow regime, lake and aquifer levels, water quality, ice cover, suspended load, primary and secondary production, trophic dynamics, organism ranges, and migration patterns.

  11. Communicating Climate and Ecosystem Change in the Arctic

    NASA Astrophysics Data System (ADS)

    Soreide, N. N.; Overland, J. E.; Calder, J. A.; Rodionov, S.

    2005-12-01

    There is an explosion of interest in Northern Hemisphere climate, highlighting the importance of recent changes in the Arctic on mid-latitude climate and its impact on marine and terrestrial ecosystems. Traditional sea ice and tundra dominated arctic ecosystems are being reorganizing into warmer sub-arctic ecosystem types. Over the previous two years we have developed a comprehensive, near real-time arctic change detection protocol to track physical and biological changes for presentation on the web: http://www.arctic.noaa.gov/detect. The effort provides a continuous update to the Arctic Climate Impact Assessment (ACIA) Report, released in November 2004. Principles for the protocol include an accessible narrative style, scientifically credible and objective indicators, notes multiple uses for the information, acknowledges uncertainties, and balances having too many indicators-which leads to information overload-and too few-which does not capture the complexity of the system. Screening criteria include concreteness, public awareness, being understandable, availability of historical time series, and sensitivity. The site provides sufficient information for an individual to make their own assessment regarding the balance of the evidence for tracking change. The product provides an overview, recent news, links to many arctic websites, and highlights climate, global impacts, land and marine ecosystems, and human consequences. Since its inception a year ago, it has averaged about 9000 hits an day on the web, and is a major information source as determined by Google search. The future direction focuses on understanding the causes for change. In spring 2005 we also presented a near real-time ecological and climatic surveillance website for the Bering Sea: www.beringclimate.noaa.gov. The site provides up-to-date information which ties northward shifts of fish, invertebrate and marine mammal populations to physical changes in the Arctic. This site is more technical than the

  12. Functional consequences of realistic biodiversity changes in a marine ecosystem

    PubMed Central

    Bracken, Matthew E. S.; Friberg, Sara E.; Gonzalez-Dorantes, Cirse A.; Williams, Susan L.

    2008-01-01

    Declines in biodiversity have prompted concern over the consequences of species loss for the goods and services provided by natural ecosystems. However, relatively few studies have evaluated the functional consequences of realistic, nonrandom changes in biodiversity. Instead, most designs have used randomly selected assemblages from a local species pool to construct diversity gradients. It is therefore difficult, based on current evidence, to predict the functional consequences of realistic declines in biodiversity. In this study, we used tide pool microcosms to demonstrate that the effects of real-world changes in biodiversity may be very different from those of random diversity changes. Specifically, we measured the relationship between the diversity of a seaweed assemblage and its ability to use nitrogen, a key limiting nutrient in nearshore marine systems. We quantified nitrogen uptake using both experimental and model seaweed assemblages and found that natural increases in diversity resulted in enhanced rates of nitrogen use, whereas random diversity changes had no effect on nitrogen uptake. Our results suggest that understanding the real-world consequences of declining biodiversity will require addressing changes in species performance along natural diversity gradients and understanding the relationships between species' susceptibility to loss and their contributions to ecosystem functioning. PMID:18195375

  13. Vulnerability to climate-induced changes in ecosystem services of boreal forests

    NASA Astrophysics Data System (ADS)

    Holmberg, Maria; Rankinen, Katri; Aalto, Tuula; Akujärvi, Anu; Nadir Arslan, Ali; Liski, Jari; Markkanen, Tiina; Mäkelä, Annikki; Peltoniemi, Mikko

    2016-04-01

    Boreal forests provide an array of ecosystem services. They regulate climate, and carbon, water and nutrient fluxes, and provide renewable raw material, food, and recreational possibilities. Rapid climate warming is projected for the boreal zone, and has already been observed in Finland, which sets these services at risk. MONIMET (LIFE12 ENV/FI/000409, 2.9.2013 - 1.9.2017) is a project funded by EU Life programme about Climate Change Indicators and Vulnerability of Boreal Zone Applying Innovative Observation and Modeling Techniques. The coordinating beneficiary of the project is the Finnish Meteorological Institute. Associated beneficiaries are the Natural Resources Institute Finland, the Finnish Environment Institute and the University of Helsinki. In the MONIMET project, we use state-of-the-art models and new monitoring methods to investigate the impacts of a warming climate on the provision of ecosystem services of boreal forests. This poster presents results on carbon storage in soil and assessment of drought indices, as a preparation for assessing the vulnerability of society to climate-induced changes in ecosystem services. The risk of decreasing provision of ecosystem services depends on the sensitivity of the ecosystem as well as its exposure to climate stress. The vulnerability of society, in turn, depends on the risk of decreasing provision of a certain service in combination with society's demand for that service. In the next phase, we will look for solutions to challenges relating to the quantification of the demand for ecosystem services and differences in spatial extent and resolution of the information on future supply and demand.

  14. Mammalian herbivores confer resilience of Arctic shrub-dominated ecosystems to changing climate.

    PubMed

    Kaarlejärvi, Elina; Hoset, Katrine S; Olofsson, Johan

    2015-09-01

    Climate change is resulting in a rapid expansion of shrubs in the Arctic. This expansion has been shown to be reinforced by positive feedbacks, and it could thus set the ecosystem on a trajectory toward an alternate, more productive regime. Herbivores, on the other hand, are known to counteract the effects of simultaneous climate warming on shrub biomass. However, little is known about the impact of herbivores on resilience of these ecosystems, that is, the capacity of a system to absorb disturbance and still remain in the same regime, retaining the same function, structure, and feedbacks. Here, we investigated how herbivores affect resilience of shrub-dominated systems to warming by studying the change of shrub biomass after a cessation of long-term experimental warming in a forest-tundra ecotone. As predicted, warming increased the biomass of shrubs, and in the absence of herbivores, shrub biomass in tundra continued to increase 4 years after cessation of the artificial warming, indicating that positive effects of warming on plant growth may persist even over a subsequent colder period. Herbivores contributed to the resilience of these systems by returning them back to the original low-biomass regime in both forest and tundra habitats. These results support the prediction that higher shrub biomass triggers positive feedbacks on soil processes and microclimate, which enable maintaining the rapid shrub growth even in colder climates. Furthermore, the results show that in our system, herbivores facilitate the resilience of shrub-dominated ecosystems to climate warming. PMID:25967156

  15. Potential climate change impacts on temperate forest ecosystem processes

    USGS Publications Warehouse

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

    2013-01-01

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

  16. Criteria for assessing climate change impacts on ecosystems

    PubMed Central

    Loehle, Craig

    2011-01-01

    There is concern about the potential impacts of climate change on species and ecosystems. To address this concern, a large body of literature has developed in which these impacts are assessed. In this study, criteria for conducting reliable and useful assessments of impacts of future climate are suggested. The major decisions involve: clearly defining an emissions scenario; selecting a climate model; evaluating climate model skill and bias; quantifying General Circulation Model (GCM) between-model variability; selecting an ecosystem model and assessing uncertainty; properly considering transient versus equilibrium responses; including effects of CO2 on plant response; evaluating implications of simplifying assumptions; and considering animal linkage with vegetation. A sample of the literature was surveyed in light of these criteria. Many of the studies used climate simulations that were >10 years old and not representative of best current models. Future effects of elevated CO2 on plant drought resistance and productivity were generally included in growth model studies but not in niche (habitat suitability) studies, causing the latter to forecast greater future adverse impacts. Overly simplified spatial representation was frequent and caused the existence of refugia to be underestimated. Few studies compared multiple climate simulations and ecosystem models (including parametric uncertainty), leading to a false impression of precision and potentially arbitrary results due to high between-model variance. No study assessed climate model retrodictive skill or bias. Overall, most current studies fail to meet all of the proposed criteria. Suggestions for improving assessments are provided. PMID:22393483

  17. Fungal community on decomposing leaf litter undergoes rapid successional changes

    PubMed Central

    Voříšková, Jana; Baldrian, Petr

    2013-01-01

    Fungi are considered the primary decomposers of dead plant biomass in terrestrial ecosystems. However, current knowledge regarding the successive changes in fungal communities during litter decomposition is limited. Here we explored the development of the fungal community over 24 months of litter decomposition in a temperate forest with dominant Quercus petraea using 454-pyrosequencing of the fungal internal transcribed spacer (ITS) region and cellobiohydrolase I (cbhI) genes, which encode exocellulases, to specifically address cellulose decomposers. To quantify the involvement of phyllosphere fungi in litter decomposition, the fungal communities in live leaves and leaves immediately before abscission were also analysed. The results showed rapid succession of fungi with dramatic changes in the composition of the fungal community. Furthermore, most of the abundant taxa only temporarily dominated in the substrate. Fungal diversity was lowest at leaf senescence, increased until month 4 and did not significantly change during subsequent decomposition. Highly diverse community of phyllosphere fungi inhabits live oak leaves 2 months before abscission, and these phyllosphere taxa comprise a significant share of the fungal community during early decomposition up to the fourth month. Sequences assigned to the Ascomycota showed highest relative abundances in live leaves and during the early stages of decomposition. In contrast, the relative abundance of sequences assigned to the Basidiomycota phylum, particularly basidiomycetous yeasts, increased with time. Although cellulose was available in the litter during all stages of decomposition, the community of cellulolytic fungi changed substantially over time. The results indicate that litter decomposition is a highly complex process mediated by various fungal taxa. PMID:23051693

  18. Fungal community on decomposing leaf litter undergoes rapid successional changes.

    PubMed

    Voříšková, Jana; Baldrian, Petr

    2013-03-01

    Fungi are considered the primary decomposers of dead plant biomass in terrestrial ecosystems. However, current knowledge regarding the successive changes in fungal communities during litter decomposition is limited. Here we explored the development of the fungal community over 24 months of litter decomposition in a temperate forest with dominant Quercus petraea using 454-pyrosequencing of the fungal internal transcribed spacer (ITS) region and cellobiohydrolase I (cbhI) genes, which encode exocellulases, to specifically address cellulose decomposers. To quantify the involvement of phyllosphere fungi in litter decomposition, the fungal communities in live leaves and leaves immediately before abscission were also analysed. The results showed rapid succession of fungi with dramatic changes in the composition of the fungal community. Furthermore, most of the abundant taxa only temporarily dominated in the substrate. Fungal diversity was lowest at leaf senescence, increased until month 4 and did not significantly change during subsequent decomposition. Highly diverse community of phyllosphere fungi inhabits live oak leaves 2 months before abscission, and these phyllosphere taxa comprise a significant share of the fungal community during early decomposition up to the fourth month. Sequences assigned to the Ascomycota showed highest relative abundances in live leaves and during the early stages of decomposition. In contrast, the relative abundance of sequences assigned to the Basidiomycota phylum, particularly basidiomycetous yeasts, increased with time. Although cellulose was available in the litter during all stages of decomposition, the community of cellulolytic fungi changed substantially over time. The results indicate that litter decomposition is a highly complex process mediated by various fungal taxa. PMID:23051693

  19. Climate change impact on peatland and forest ecosystems of Russia

    SciTech Connect

    Kondrasheva, N.Yu.; Kobak, K.I.; Turchinovich, I.Ye.

    1996-12-31

    Paleoclimatic and paleobotanic reconstructions allow a conclusion that ecosystems and natural zones significantly changed due to climate fluctuations. The average long-term carbon accumulation in peatlands of Russia was estimated as 45.6 mln tons of carbon per year. During the Holocene the rate of peat accumulation changed. During the Subboreal period the rate of peat accumulation gradually decreased to 17 gC/m2 yr, reaching its lowest value in the Subatlantic period. Apparently, the rate of peat accumulation decreased in Subboreal period due to sharp cooling and precipitation decrease. Future rates of peat accumulation might be higher than the present one. Forest ecosystems of north-western Russia also significantly changed during the Holocene. In Atlantic time the boundary between middle and south taiga was located 500 km northward compared to the present and broad-leaved forest occupied large areas. According to their forecast, a mean global air temperature increase by 1.4 C is expected to result in a considerable decrease in coniferous forest area and an increase in mixed and broad-leaved forest area.

  20. Rapid climate change: scientific challenges and the new NERC programme.

    PubMed

    Srokosz, M A

    2003-09-15

    In this paper the scientific challenges of observing, modelling, understanding and predicting rapid changes in climate are discussed, with a specific focus on the role of the Atlantic thermohaline circulation. The palaeo and present-day observational and modelling studies being carried out to meet these challenges, under the aegis of a new NERC Rapid Climate Change thematic programme (RAPID), are outlined. In particular, the paper describes the work being done to monitor changes in the meridional overturning circulation of the North Atlantic. The paper concludes with some speculative comments about potential mechanisms for rapid changes. PMID:14558909

  1. Seasonal changes of water carbon relations in savanna ecosystems

    NASA Astrophysics Data System (ADS)

    Kutsch, W. L.; Merbold, L.; Archibald, S.

    2011-12-01

    During evolution plant species have developed different strategies to optimize the water carbon relations. These stratgies summarize to ecosystem properties. As an example we show how tropical and subtropical savannas and woodlands can respond flexibly to changes in temperature and water availability and thus optimize carbon and water fluxes between land surface and atmosphere. Several phenomena are presented and discussed in this overview from African flux sites in Zambia, Burkina Faso and South Africa: Pre-rain leaf development: Many trees developed new leaves before the first rain appeared. As a consequence of this early timing of leaf flush, the phenological increase of photosynthetic capacity (Amax) was steeper than in temperate forests. Mid-term response of conductance and photosynthesis to soil water relations: The regulation of canopy conductance was temporally changing in two ways: changes due to phenology during the course of the growing season and short-term (hours to days) acclimation to soil water conditions. The most constant parameter was water use efficiency. It was influenced by water vapour pressure deficit (VPD) during the day, but the VPD response curve of water usage only changed slightly during the course of the growing season, and decreased by about 30% during the transition from wet to dry season. The regulation of canopy conductance and photosynthetic capacity were closely related. This observation meets recent leaf-level findings that stomatal closure triggers down-regulation of Rubisco during drought. Our results may show the effects of these processes on the ecosystem scale. Furthermore, we observed that the close relationship between stomatal conductance and photosynthesis resulted in different temperature optima of GPP that were close to the average daytime temperature. Adaptation of respiration to rain pulses: Finally, the response of respiration to rain pulses showed changes throughout the growing season. The first rain events early

  2. Projected future climate change and Baltic Sea ecosystem management.

    PubMed

    Andersson, Agneta; Meier, H E Markus; Ripszam, Matyas; Rowe, Owen; Wikner, Johan; Haglund, Peter; Eilola, Kari; Legrand, Catherine; Figueroa, Daniela; Paczkowska, Joanna; Lindehoff, Elin; Tysklind, Mats; Elmgren, Ragnar

    2015-06-01

    Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 °C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase ~30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes. PMID:26022318

  3. Disturbances, organisms and ecosystems: a global change perspective

    PubMed Central

    Ponge, Jean-François

    2013-01-01

    The present text exposes a theory of the role of disturbances in the assemblage and evolution of species within ecosystems, based principally, but not exclusively, on terrestrial ecosystems. Two groups of organisms, doted of contrasted strategies when faced with environmental disturbances, are presented, based on the classical r-K dichotomy, but enriched with more modern concepts from community and evolutionary ecology. Both groups participate in the assembly of known animal, plant, and microbial communities, but with different requirements about environmental fluctuations. The so-called “civilized” organisms are doted with efficient anticipatory mechanisms, allowing them to optimize from an energetic point of view their performances in a predictable environment (stable or fluctuating cyclically at the scale of life expectancy), and they developed advanced specializations in the course of evolutionary time. On the opposite side, the so-called “barbarians” are weakly efficient in a stable environment because they waste energy for foraging, growth, and reproduction, but they are well adapted to unpredictably changing conditions, in particular during major ecological crises. Both groups of organisms succeed or alternate each other in the course of spontaneous or geared successional processes, as well as in the course of evolution. The balance of “barbarians” against “civilized” strategies within communities is predicted to shift in favor of the first type under present-day anthropic pressure, exemplified among others by climate warming, land use change, pollution, and biological invasions. PMID:23610648

  4. Vulnerability of ecosystems to climate change moderated by habitat intactness.

    PubMed

    Eigenbrod, Felix; Gonzalez, Patrick; Dash, Jadunandan; Steyl, Ilse

    2015-01-01

    The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48×48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8×4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large-scale refugia is the priority. In human-dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large-scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network. PMID:25059822

  5. CLIMATE CHANGE 2001: CHAP. 5: ECOSYSTEMS AND THEIR GOODS AND SERVICES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecosystems are subject to many pressures (e.g., land-use change, resource demands, population changes); their extent and pattern of distribution is changing, and landscapes are becoming more fragmented. Climate change constitutes an additional pressure that could change or endanger ecosystems and th...

  6. Climate change effects on groundwater dependent temperate forest ecosystems

    NASA Astrophysics Data System (ADS)

    Bierkens, M. F.; Brolsma, R. J.; van Beek, R. L.; van Vliet, M. T.

    2008-12-01

    Models developed to predict the influence of changing climate on ecosystems often concentrate on vegetation in connection with soil moisture, but usually omit groundwater. However in temperate climate zones, groundwater can have a profound effect on the reaction of vegetation to climate change, because it strongly influences the spatio-temporal distribution of soil moisture and therefore water and oxygen stress of vegetation. Here we focus on the qualitative and quantitative effects of climate change on the zonation of vegetation and groundwater dynamics along a hill slope. To study this we developed a fully coupled hydrological-vegetation model, for a groundwater influenced temperate forest ecosystem. The vegetation model is based on the carbon assimilation model of Farquhar et al. (1980) and the extension of Daly et al. (2004), which includes transpiration of vegetation and accounts for the response to low soil moisture content. We modified this model to account for vegetation response to high soil moisture contents due to high groundwater levels, and we extended the model to include light competition, phenology and vegetation growth. To simulate the hydrological system the saturated-unsaturated flow model by van Beek (2002) is used. The coupled model was first compared to measured semi-hourly flux tower data of H2O and CO2, showing good results. Than simulation runs of 1000 years were performed to study the effect of climate change on soil water, groundwater and vegetation. We performed simulation runs with competition between wet and dry adapted species under current conditions and after climate change. Meteorological time series for the 2100 climate (SRESA2) were obtained from downscaling 6 different regional climate model runs from the ENSEMBLES project with a stochastic weather generator (Kilby et al., 2007). Results show that in the zones were the groundwater system is close to the surface, climate change causes large shifts in vegetation zonation of the

  7. Fluctuation-induced patterns and rapid evolution in predator-prey ecosystems

    NASA Astrophysics Data System (ADS)

    Goldenfeld, Nigel

    2014-03-01

    Predator-prey ecosystems exhibit noisy, persistent cycles that cannot be described by intuitive population-level differential equations such as the Lotka-Volterra equations. Traditionally this paradox has been met by including additional nonlinearities such as predator satiation to force limit cycle behavior. Over the last few years, it has been realized that individual-level descriptions, combined with systematic perturbation techniques can reproduce the key features of such systems in a minimal way, without requiring many additional assumptions or fine tunings. Here I review work in this area that uses these techniques to treat spatial patterns and the phenomenon of rapidly evolving prey sub-populations. In the latter case, I show how stochastic individual-level models reproduce the key features observed in chemostats and in the wild, including anomalous phase shifts between predator and prey species, evolutionary cycles and cryptic cycles. This work shows that stochastic individual-level models naturally describe systems where evolutionary time scales surprisingly match ecosystem time scales.

  8. Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo.

    PubMed

    Labrière, Nicolas; Laumonier, Yves; Locatelli, Bruno; Vieilledent, Ghislain; Comptour, Marion

    2015-01-01

    Because industrial agriculture keeps expanding in Southeast Asia at the expense of natural forests and traditional swidden systems, comparing biodiversity and ecosystem services in the traditional forest-swidden agriculture system vs. monocultures is needed to guide decision making on land-use planning. Focusing on tree diversity, soil erosion control, and climate change mitigation through carbon storage, we surveyed vegetation and monitored soil loss in various land-use areas in a northern Bornean agricultural landscape shaped by swidden agriculture, rubber tapping, and logging, where various levels and types of disturbance have created a fine mosaic of vegetation from food crop fields to natural forest. Tree species diversity and ecosystem service production were highest in natural forests. Logged-over forests produced services similar to those of natural forests. Land uses related to the swidden agriculture system largely outperformed oil palm or rubber monocultures in terms of tree species diversity and service production. Natural and logged-over forests should be maintained or managed as integral parts of the swidden system, and landscape multifunctionality should be sustained. Because natural forests host a unique diversity of trees and produce high levels of ecosystem services, targeting carbon stock protection, e.g. through financial mechanisms such as Reducing Emissions from Deforestation and Forest Degradation (REDD+), will synergistically provide benefits for biodiversity and a wide range of other services. However, the way such mechanisms could benefit communities must be carefully evaluated to counter the high opportunity cost of conversion to monocultures that might generate greater income, but would be detrimental to the production of multiple ecosystem services. PMID:26466120

  9. Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo

    PubMed Central

    Labrière, Nicolas; Laumonier, Yves; Locatelli, Bruno; Vieilledent, Ghislain; Comptour, Marion

    2015-01-01

    Because industrial agriculture keeps expanding in Southeast Asia at the expense of natural forests and traditional swidden systems, comparing biodiversity and ecosystem services in the traditional forest–swidden agriculture system vs. monocultures is needed to guide decision making on land-use planning. Focusing on tree diversity, soil erosion control, and climate change mitigation through carbon storage, we surveyed vegetation and monitored soil loss in various land-use areas in a northern Bornean agricultural landscape shaped by swidden agriculture, rubber tapping, and logging, where various levels and types of disturbance have created a fine mosaic of vegetation from food crop fields to natural forest. Tree species diversity and ecosystem service production were highest in natural forests. Logged-over forests produced services similar to those of natural forests. Land uses related to the swidden agriculture system largely outperformed oil palm or rubber monocultures in terms of tree species diversity and service production. Natural and logged-over forests should be maintained or managed as integral parts of the swidden system, and landscape multifunctionality should be sustained. Because natural forests host a unique diversity of trees and produce high levels of ecosystem services, targeting carbon stock protection, e.g. through financial mechanisms such as Reducing Emissions from Deforestation and Forest Degradation (REDD+), will synergistically provide benefits for biodiversity and a wide range of other services. However, the way such mechanisms could benefit communities must be carefully evaluated to counter the high opportunity cost of conversion to monocultures that might generate greater income, but would be detrimental to the production of multiple ecosystem services. PMID:26466120

  10. Higher Education: A Rapidly Changing Landscape.

    ERIC Educational Resources Information Center

    WorkAmerica, 2002

    2002-01-01

    In a world of constantly changing demands for knowledge and technical skills for the work world, higher education has been slow to change to meet these demands. The numbers of American students receiving bachelor's degrees in engineering, mathematics, and computer science fell significantly between 1987 and 1998, while the demand rose. In…

  11. Symptoms of change in multi-scale observations of arctic ecosystem carbon cycling

    NASA Astrophysics Data System (ADS)

    Stoy, P. C.; Williams, M. D.; Hartley, I. P.; Street, L.; Hill, T. C.; Prieto-Blanco, A.; Wayolle, A.; Disney, M.; Evans, J.; Fletcher, B.; Poyatos, R.; Wookey, P.; Merbold, L.; Wade, T. J.; Moncrieff, J.

    2009-12-01

    Arctic ecosystems are responding rapidly to observed climate change. Quantifying the magnitude of these changes, and their implications for the climate system, requires observations of their current structure and function, as well as extrapolation and modelling (i.e. ‘upscaling’) across time and space. Here, we describe the major results of the International Polar Year (IPY) ABACUS project, a multi-scale investigation across arctic Fennoscandia that couples plant and soil process studies, isotope analyses, flux and micrometeorological measurements, process modelling, and aircraft and satellite observations to improve predictions of the response of the arctic terrestrial biosphere to global change. We begin with a synthesis of eddy covariance observations from the global FLUXNET database. We demonstrate that a simple model parameterized using pan-arctic chamber measurements explains over 80% of the variance of half-hourly CO2 fluxes during the growing season across most arctic and montane tundra ecosystems given accurate measurements of leaf area index (LAI), which agrees with the recently proposed ‘functional convergence’ paradigm for tundra vegetation. The ability of MODIS to deliver accurate LAI estimates is briefly discussed and an adjusted algorithm is presented and validated using direct observations. We argue for an Information Theory-based framework for upscaling in Earth science by conceptualizing multi-scale research as a transfer of information across scales. We then demonstrate how error in upscaled arctic C flux estimates can be reduced to less than 4% from their high-resolution counterpart by formally preserving the information content of high spatial and spectral resolution aircraft and satellite imagery. Jaynes’ classic Maximum Entropy (MaxEnt) principle is employed to incorporate logical, biological and physical constraints to reduce error in downscaled flux estimates. Errors are further reduced by assimilating flux, biological and remote

  12. Sensitivity and rapidity of vegetational response to abrupt climate change

    NASA Technical Reports Server (NTRS)

    Peteet, D.

    2000-01-01

    Rapid climate change characterizes numerous terrestrial sediment records during and since the last glaciation. Vegetational response is best expressed in terrestrial records near ecotones, where sensitivity to climate change is greatest, and response times are as short as decades.

  13. Hydrologically driven ecosystem processes determine the distribution and persistence of ecosystem-specialist predators under climate change.

    PubMed

    Carroll, Matthew J; Heinemeyer, Andreas; Pearce-Higgins, James W; Dennis, Peter; West, Chris; Holden, Joseph; Wallage, Zoe E; Thomas, Chris D

    2015-01-01

    Climate change has the capacity to alter physical and biological ecosystem processes, jeopardizing the survival of associated species. This is a particular concern in cool, wet northern peatlands that could experience warmer, drier conditions. Here we show that climate, ecosystem processes and food chains combine to influence the population performance of species in British blanket bogs. Our peatland process model accurately predicts water-table depth, which predicts abundance of craneflies (keystone invertebrates), which in turn predicts observed abundances and population persistence of three ecosystem-specialist bird species that feed on craneflies during the breeding season. Climate change projections suggest that falling water tables could cause 56-81% declines in cranefly abundance and, hence, 15-51% reductions in the abundances of these birds by 2051-2080. We conclude that physical (precipitation, temperature and topography), biophysical (evapotranspiration and desiccation of invertebrates) and ecological (food chains) processes combine to determine the distributions and survival of ecosystem-specialist predators. PMID:26227623

  14. Hydrologically driven ecosystem processes determine the distribution and persistence of ecosystem-specialist predators under climate change

    PubMed Central

    Carroll, Matthew J.; Heinemeyer, Andreas; Pearce-Higgins, James W.; Dennis, Peter; West, Chris; Holden, Joseph; Wallage, Zoe E.; Thomas, Chris D.

    2015-01-01

    Climate change has the capacity to alter physical and biological ecosystem processes, jeopardizing the survival of associated species. This is a particular concern in cool, wet northern peatlands that could experience warmer, drier conditions. Here we show that climate, ecosystem processes and food chains combine to influence the population performance of species in British blanket bogs. Our peatland process model accurately predicts water-table depth, which predicts abundance of craneflies (keystone invertebrates), which in turn predicts observed abundances and population persistence of three ecosystem-specialist bird species that feed on craneflies during the breeding season. Climate change projections suggest that falling water tables could cause 56–81% declines in cranefly abundance and, hence, 15–51% reductions in the abundances of these birds by 2051–2080. We conclude that physical (precipitation, temperature and topography), biophysical (evapotranspiration and desiccation of invertebrates) and ecological (food chains) processes combine to determine the distributions and survival of ecosystem-specialist predators. PMID:26227623

  15. Quantifying Changes in Ecosystem Goods and Services From Land-use Change in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Zaks, D. P.; Foley, J. A.

    2007-12-01

    The Amazon basin delivers a wide array of ecosystem goods and services to recipients at local, regional and global scales. As an increasing amount of land is converted from natural vegetation to cropland, pasture, biofuel and timber production, the social, economics and biophysical changes have yet to be fully quantified across. There are inherent trade-offs of these goods and services with changes in land-use that occur across scales. Here, we begin to calculate the impact of land-use changes for commodity production across the Amazon and identify user groups and their changing levels of ecosystem services. Future synthesis work will integrate studies completed under the auspices of the Large Biosphere Atmosphere Experiment in Amazonia (LBA) with a next- generation biosphere model, similar to IBIS. Ecosystem services such as carbon sequestration, water quality / quantity, climate regulation and health will be considered. This work aims to better the understanding of the relationship between the biophysical environment and the sociosphere by using economic and statistical data on commodity production and trade to deliver spatially explicit estimates of the changes in ecosystem goods and services across the Amazon basin.

  16. Vulnerability of riparian ecosystems to elevated CO2 and climate change in arid and semiarid western North America

    USGS Publications Warehouse

    Perry, Laura G.; Andersen, Douglas C.; Reynolds, Lindsay V.; Nelson, S. Mark; Shafroth, Patrick B.

    2012-01-01

    ecosystems to allow rapid detection and response to undesirable ecological change.

  17. Rapid Temporal Changes of Boundary Layer Winds

    NASA Technical Reports Server (NTRS)

    Merceret, Francis J.

    2005-01-01

    The statistical distribution of the magnitude of the vector wind change over 0.25, 0.5, 1 and 2-h periods based on data from November 1999 through August 2001 is presented. The distributions of the 2-h u and v component wind changes are also presented for comparison. The wind changes at altitudes from 500 to 3000 m were measured using the Eastern Range network of five 915 MHz Doppler radar wind profilers. Quality controlled profiles were produced every 15 minutes for up to sixty gates, each representing 101 m in altitude over the range from 130 m to 6089 m. Five levels, each constituting three consecutive gates, were selected for analysis because of their significance to aerodynamic loads during the Space Shuttle ascent roll maneuver. The distribution of the magnitude of the vector wind change is found to be lognormal consistent with earlier work in the mid-troposphere. The parameters of the distribution vary with time lag, season and altitude. The component wind changes are symmetrically distributed with near-zero means, but the kurtosis coefficient is larger than that of a Gaussian distribution.

  18. USGS: Science to understand and forecast change in coastal ecosystems

    USGS Publications Warehouse

    Myers, M.

    2007-01-01

    The multidisciplinary approach of the US Geological Survey (USGS), a principal science agency of the US Department of the Interior (DOI), to address the complex and cumulative impacts of human activities and natural events on the US coastal ecosystems has been considered remarkable for understanding and forecasting the changes. The USGS helps explain geologic, hydrologic, and biologic systems and their connectivity across landscapes and seascapes along the coastline. The USGS coastal science programs effectively address science and information to other scientists, managers, policy makers, and the public. The USGS provides scientific expertise, capabilities, and services to collaborative federal, regional, and state-led efforts, which are in line with the goals of Ocean Action Plan (OAP) and Ocean Research Priorities Plan (ORPP). The organization is a leader in understanding terrestrial and marine environmental hazards such as earthquakes, tsunamis, floods, and landslides and assessing and forecasting coastal impacts using various specialized visualization techniques.

  19. Regional climate change, ecosystem responses, and climate feedbacks

    NASA Astrophysics Data System (ADS)

    Cook, Benjamin Issac

    2007-12-01

    I use empirical/statistical models and physically based general circulation models to assess the capacity for the Arctic Oscillation (AO) and the El Nino Southern Oscillation (ENSO) to influence terrestrial ecosystems, and the potential for those ecosystems to feedback to the climate system. AO warming leads to modest reductions in Eurasian carbon stocks; ˜17 Pg carbon are lost to the atmosphere, primarily from increased soil decomposition. Precipitation reductions in southern Africa associated with increased frequency of El Nino events lead to a reduction in tree cover and expansion of grasslands in the north and a reduction in grass cover in drier areas. Here half the carbon cycle changes are driven by the loss of tree cover, leading to a net loss of ˜5 Pg of carbon to the atmosphere. Over southern Africa, positive soil moisture anomalies lead to reduced precipitation through enhanced subsidence and reduced moisture convergence. Higher snow cover alone in Eurasia leads to minor albedo increases and moderate localized cooling (3°-5°C), mostly at very high latitudes (>70°N) and during the spring season. When vegetation is allowed to interact, increased snow cover leads to southward retreat of boreal vegetation, widespread cooling, and persistent snow cover over much of the boreal region during the boreal summer, with cold anomalies of up to 15°C. In southern Africa, the feedback experiments suggest a negative feedback between soil moisture and precipitation over the same area, implying this region may be resistant to externally forced changes in precipitation. In Eurasia, a persistent high phase of the AO leads to winter warming, but the feedback response is complicated. Warming during this season has been associated with increased snowfall, which could increase snow cover and albedo, countering the AO warming. Conversely, increased temperatures could lead to increased snow melting and decreased albedo, amplifying the AO warming.

  20. Regional Approach for Linking Ecosystem Services and Livelihood Strategies Under Climate Change of Pastoral Communities in the Mongolian Steppe Ecosystem

    NASA Astrophysics Data System (ADS)

    Ojima, D. S.; Galvin, K.; Togtohyn, C.

    2012-12-01

    Dramatic changes due to climate and land use dynamics in the Mongolian Plateau affecting ecosystem services and agro-pastoral systems in Mongolia. Recently, market forces and development strategies are affecting land and water resources of the pastoral communities which are being further stressed due to climatic changes. Evaluation of pastoral systems, where humans depend on livestock and grassland ecosystem services, have demonstrated the vulnerability of the social-ecological system to climate change. Current social-ecological changes in ecosystem services are affecting land productivity and carrying capacity, land-atmosphere interactions, water resources, and livelihood strategies. The general trend involves greater intensification of resource exploitation at the expense of traditional patterns of extensive range utilization. Thus we expect climate-land use-land cover relationships to be crucially modified by the social-economic forces. The analysis incorporates information about the social-economic transitions taking place in the region which affect land-use, food security, and ecosystem dynamics. The region of study extends from the Mongolian plateau in Mongolia. Our research indicate that sustainability of pastoral systems in the region needs to integrate the impact of climate change on ecosystem services with socio-economic changes shaping the livelihood strategies of pastoral systems in the region. Adaptation strategies which incorporate integrated analysis of landscape management and livelihood strategies provides a framework which links ecosystem services to critical resource assets. Analysis of the available livelihood assets provides insights to the adaptive capacity of various agents in a region or in a community. Sustainable development pathways which enable the development of these adaptive capacity elements will lead to more effective adaptive management strategies for pastoral land use and herder's living standards. Pastoralists will have the

  1. Climate change impacts on stream carbon export from coastal temperate rainforest ecosystems in Alaska (Invited)

    NASA Astrophysics Data System (ADS)

    Hood, E. W.

    2013-12-01

    Coastal temperate rainforests (CTR) in Alaska contain about 10% of the total carbon in the forests of the conterminous United States. CTR ecosystems span a large environmental gradient that ranges from icefields mantling the Coast Mountains to carbon-rich conifer forests along the coastal margin and within the islands of the Alexander Archipelago in the Gulf of Alaska. Riverine dissolved organic carbon (DOC) export from Alaskan CTR ecosystems, which can exceed 2 Tg C yr-1, is large relative to other northern ecosystems as a result of high rates of specific discharge (~2.5 m yr-1) and an abundance of organic soils found in peatlands and forested wetlands. Runoff from glaciers, which are rapidly thinning and retreating, has also been shown to an important contributor to land-to-ocean fluxes of DOC in this region. Downscaled regional climate models suggest that CTR ecosystems in Alaska will become warmer and wetter in coming decades, with uncertain effects on riverine organic matter (OM) export. Changes in watershed OM export are likely to be driven by changes in both hydrology and the availability of OM in terrestrial source pools. However, the impacts of these climate driven changes will vary with watershed landcover across the continuum from icefields to coastal temperate forests. Expected hydrological perturbations include changes in the timing and magnitude of streamflow associated with shifts in: 1) the extent and duration of seasonal snowcover and 2) the mass balance of glaciers and icefields in the Coast Mountains. The availability of OM for export along hydrologic flowpaths will likely be altered by increased soil temperatures and shifts in water table elevations during the summer/fall runoff season. This will be particularly true for organic carbon export from peatlands in which changes in temperature and oxygen availability can strongly impact rates of organic matter decomposition. This talk will explore how climate-driven changes in hydrology and

  2. Climate change impacts on potential recruitment in an ecosystem engineer.

    PubMed

    Morgan, Emer; O' Riordan, Ruth M; Culloty, Sarah C

    2013-03-01

    Climate variability and the rapid warming of seas undoubtedly have huge ramifications for biological processes such as reproduction. As such, gametogenesis and spawning were investigated at two sites over 200 km apart on the south coast of Ireland in an ecosystem engineer, the common cockle, Cerastoderma edule. Both sites are classed as Special Areas of Conservation (SACs), but are of different water quality. Cerastoderma edule plays a significant biological role by recycling nutrients and affecting sediment structure, with impacts upon assemblage biomass and functional diversity. It plays a key role in food webs, being a common foodstuff for a number of marine birds including the oystercatcher. Both before and during the study (early 2010-mid 2011), Ireland experienced its two coldest winters for 50 years. As the research demonstrated only slight variation in the spawning period between sites, despite site differences in water and environmental quality, temperature and variable climatic conditions were the dominant factor controlling gametogenesis. The most significant finding was that the spawning period in the cockle extended over a greater number of months compared with previous studies and that gametogenesis commenced over winter rather than in spring. Extremely cold winters may impact on the cockle by accelerating and extending the onset and development of gametogenesis. Whether this impact is positive or negative would depend on the associated events occurring on which the cockle depends, that is, presence of primary producers and spring blooms, which would facilitate conversion of this extended gametogenesis into successful recruitment. PMID:23532482

  3. Climate change impacts on potential recruitment in an ecosystem engineer

    PubMed Central

    Morgan, Emer; O' Riordan, Ruth M; Culloty, Sarah C

    2013-01-01

    Climate variability and the rapid warming of seas undoubtedly have huge ramifications for biological processes such as reproduction. As such, gametogenesis and spawning were investigated at two sites over 200 km apart on the south coast of Ireland in an ecosystem engineer, the common cockle, Cerastoderma edule. Both sites are classed as Special Areas of Conservation (SACs), but are of different water quality. Cerastoderma edule plays a significant biological role by recycling nutrients and affecting sediment structure, with impacts upon assemblage biomass and functional diversity. It plays a key role in food webs, being a common foodstuff for a number of marine birds including the oystercatcher. Both before and during the study (early 2010–mid 2011), Ireland experienced its two coldest winters for 50 years. As the research demonstrated only slight variation in the spawning period between sites, despite site differences in water and environmental quality, temperature and variable climatic conditions were the dominant factor controlling gametogenesis. The most significant finding was that the spawning period in the cockle extended over a greater number of months compared with previous studies and that gametogenesis commenced over winter rather than in spring. Extremely cold winters may impact on the cockle by accelerating and extending the onset and development of gametogenesis. Whether this impact is positive or negative would depend on the associated events occurring on which the cockle depends, that is, presence of primary producers and spring blooms, which would facilitate conversion of this extended gametogenesis into successful recruitment. PMID:23532482

  4. Responses of ecosystem carbon cycling to climate change treatments along an elevation gradient

    USGS Publications Warehouse

    Wu, Zhuoting; Koch, George W.; Dijkstra, Paul; Bowker, Matthew A.; Hungate, Bruce A.

    2011-01-01

    Global temperature increases and precipitation changes are both expected to alter ecosystem carbon (C) cycling. We tested responses of ecosystem C cycling to simulated climate change using field manipulations of temperature and precipitation across a range of grass-dominated ecosystems along an elevation gradient in northern Arizona. In 2002, we transplanted intact plant–soil mesocosms to simulate warming and used passive interceptors and collectors to manipulate precipitation. We measured daytime ecosystem respiration (ER) and net ecosystem C exchange throughout the growing season in 2008 and 2009. Warming generally stimulated ER and photosynthesis, but had variable effects on daytime net C exchange. Increased precipitation stimulated ecosystem C cycling only in the driest ecosystem at the lowest elevation, whereas decreased precipitation showed no effects on ecosystem C cycling across all ecosystems. No significant interaction between temperature and precipitation treatments was observed. Structural equation modeling revealed that in the wetter-than-average year of 2008, changes in ecosystem C cycling were more strongly affected by warming-induced reduction in soil moisture than by altered precipitation. In contrast, during the drier year of 2009, warming induced increase in soil temperature rather than changes in soil moisture determined ecosystem C cycling. Our findings suggest that warming exerted the strongest influence on ecosystem C cycling in both years, by modulating soil moisture in the wet year and soil temperature in the dry year.

  5. Changing arctic ecosystems—What is causing the rapid increase of snow geese in northern Alaska?

    USGS Publications Warehouse

    Hupp, Jerry W.; Ward, David H.; Whalen, Mary E.; Pearce, John M.

    2015-01-01

    Through the Changing Arctic Ecosystems (CAE) initiative, the U.S. Geological Survey (USGS) informs key resource management decisions for Arctic Alaska by providing scientific information on current and future ecosystem response to a warming climate. The Arctic Coastal Plain (ACP) of northern Alaska is a key study area within the USGS CAE initiative. This region has experienced a warming trend over the past decades, leading to decreased sea ice, permafrost thaw, and an advancement of spring phenology. The number of birds on the ACP also is changing, marked by increased populations of the four species of geese that nest in the region. The Snow Goose (Chen caerulescens) is the most rapidly increasing of these species. USGS CAE research is quantifying these changes and their implications for management agencies.

  6. Rapid Temporal Changes of Midtropospheric Winds

    NASA Technical Reports Server (NTRS)

    Merceret, Francis J.

    1997-01-01

    The statistical distribution of the magnitude of the vector wind change over 0.25-, 1-, 2-. and 4-h periods based on data from October 1995 through March 1996 over central Florida is presented. The wind changes at altitudes from 6 to 17 km were measured using the Kennedy Space Center 50-MHz Doppler radar wind profiler. Quality controlled profiles were produced every 5 min for 112 gates, each representing 150 m in altitude. Gates 28 through 100 were selected for analysis because of their significance to ascending space launch vehicles. The distribution was found to be lognormal. The parameters of the lognormal distribution depend systematically on the time interval. This dependence is consistent with the behavior of structure functions in the f(exp 5/3) spectral regime. There is a small difference between the 1995 data and the 1996 data, which may represent a weak seasonal effect.

  7. Climate Change Alters Seedling Emergence and Establishment in an Old-Field Ecosystem

    SciTech Connect

    Classen, Aimee T; Norby, Richard J; Campany, Courtney E; Sides, Katherine E; Weltzin, Jake

    2010-01-01

    In shaping how ecosystems respond to climatic change, ecosystem structure can dominate over physiological responses of individuals, especially under conditions of multiple, simultaneous changes in environmental factors. Ecological succession drives large-scale changes in ecosystem structure over time, but the mechanisms whereby climatic change alters succession remain unresolved. Here, we investigate effects of atmospheric and climatic change on seedling establishment, recognizing that small shifts in seedling establishment of different species may have long-term repercussions on the transition of fields to forests in the future. Our 4-year experiment in an old-field ecosystem revealed that response of seedling emergence to different combinations of atmospheric CO2 concentration, air temperature, and soil moisture depends on seed phenology, the timing of seed arrival into an ecosystem. We conclude that seed phenology is an important plant trait that can shape, and help predict, the trajectories of ecosystems under climatic change.

  8. Issues in evaluation of ecosystem change in response to global change

    SciTech Connect

    Dowlatabadi, H.; Shevliakova, E.; Kandlikar, M.

    1994-12-31

    Uncertainty analysis of our integrated climate assessment model has revealed the importance of obtaining better market and non-market impacts. Improving market and non-market damage assessments has necessitated advances in the theoretical and applied dimensions of the problem. The assessment of climate change impacts on ecosystems provides a severe test for the new ideas being put forward. This paper provides a brief overview of, (i) the challenges inherent in modeling ecosystem dynamics; (ii) the problem of selecting an appropriate metric of change; and, (iii) the thorny issue of how to place a monetary value on market and non-market impacts. We focus on two central issues in estimation of impacts: (i) before climate change, are the systems being impacted (both ecological and economic) in equilibrium? and (ii) how quickly do ecological and related economic systems adapt to change? In addition, we attempt to be comprehensive in laying out the magnitude of the challenge ahead.

  9. Olfactory processing: detection of rapid changes.

    PubMed

    Croy, Ilona; Krone, Franziska; Walker, Susannah; Hummel, Thomas

    2015-06-01

    Changes in the olfactory environment have a rather poor chance of being detected. Aim of the present study was to determine, whether the same (cued) or different (uncued) odors can generally be detected at short inter stimulus intervals (ISI) below 2.5 s. Furthermore we investigated, whether inhibition of return, an attentional phenomenon facilitating the detection of new stimuli at longer ISI, is present in the domain of olfaction. Thirteen normosmic people (3 men, 10 women; age range 19-27 years; mean age 23 years) participated. Stimulation was performed using air-dilution olfactometry with 2 odors: phenylethylalcohol and hydrogen disulfide. Reaction time to target stimuli was assessed in cued and uncued conditions at ISIs of 1, 1.5, 2, and 2.5 s. There was a significant main effect of ISI, indicating that odors presented only 1 s apart are missed frequently. Uncued presentation facilitated detection at short ISIs, implying that changes of the olfactory environment are detected better than presentation of the same odor again. Effects in relation to "olfactory inhibition of return," on the other hand, are not supported by our results. This suggests that attention works different for the olfactory system compared with the visual and auditory systems. PMID:25911421

  10. Soil ecosystem functioning under climate change: plant species and community effects

    SciTech Connect

    Kardol, Paul; Cregger, Melissa; Campany, Courtney E; Classen, Aimee T

    2010-01-01

    Feedbacks of terrestrial ecosystems to climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the microbial communities that feed on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and water availability. Specifically, we collected soils at the plot level (plant community soils), and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: 1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activities, and soil nematodes. Multiple climate change factors can interact to shape ecosystems, but in this case, those interactions were largely driven by changes in water availability. 2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning and this impact was not obvious when looking at plant community soils. Climate change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. In sum, these results indicate that accurate assessments of climate change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate change-induced shifts in plant community composition will likely modify or counteract the direct

  11. U.S. Climate change science program. Synthesis and Assessment Product 4.2: Thresholds of change in ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the past three decades, climate change has become a pronounced driver of ecosystem change. Changes in phenology, range shift of species, and increases in disturbances such as wildfires have all reflected ecosystem scales responses to a warming biosphere. There have also been abrupt, nonlinear cha...

  12. The need for simultaneous evaluation of ecosystem services and land use change

    USGS Publications Warehouse

    Euliss, Ned H.; Smith, Loren M.; Liu, Shu-Guang; Feng, Min; Mushet, David M.; Auch, Roger F.; Loveland, Thomas R.

    2010-01-01

    We are living in a period of massive global change. This rate of change may be almost without precedent in geologic history (1). Even the most remote areas of the planet are influenced by human activities. Modern landscapes have been highly modified to accommodate a growing human population that the United Nations has forecast to peak at 9.1 billion by 2050. Over this past century, reliance on services from ecosystems has increased significantly and, over past decades, sustainability of our modern, intensively managed ecosystems has been a topic of serious international concern (1). Numerous papers addressing a particular land-use change effect on specific ecosystem services have recently been published. For example, there is currently great interest in increasing biofuel production to achieve energy inde- pendence goals and recent papers have independently focused attention on impacts of land-use change on single ecosystem services such as carbon sequestration (2) and many others (e.g., water availability, biodiversity, pollination). However, land-use change clearly affects myriad ecosystem services simultaneously. Hence, a broader perspective and context is needed to evaluate and understand interrelated affects on multiple ecosystem services, especially as we strive for the goal of sustainably managing global ecosystems. Similarly, land uses affect ecosystem services synergistically; single land-use evaluations may be misleading because the overall impact on an ecosystem is not evaluated. A more holistic approach would provide a means and framework to characterize how land-use change affects provisioning of goods and services of complete ecosystems.

  13. Rapid Changes in Mercury's Sodium Exosphere

    NASA Technical Reports Server (NTRS)

    Potter, Drew

    2000-01-01

    Sodium in the atmosphere of Mercury can be detected by sunlight scattered in the D1 and D2 resonance lines. Images of the sodium emission show that the sodium density changes from day to day and is often concentrated in regions at high or mid latitudes. Drew Potter (NASA/JSC) and Tom Morgan (SWRI) suggested that sputtering by magnetospheric particles was the origin of the sodium. A problem with this is that the magnetic field of Mercury is strong enough that it is believed to shield the surface from solar particles much of the time, although particle precipitation at the magnetospheric cusps could deposit particles to the surface at high latitudes. Ann Sprague (UA/LPL) noted that the "spots" of sodium emission tended to coincide with major geologic features, such as the Caloris Basin. She proposed that the sodium is released from sodiumrich surface rocks that are associated with these features; however, some spots have appeared where there are no obvious geologic features. Some of the difficulty in ascribing a source for the sodium arises from the effect of terrestrial atmospheric blurring of the image. It is hard to tell exactly where the sodium emission originates after the atmosphere has blurred the image. Potter, Killen (SWRI), and Morgan recently developed a technique for correcting sodium images for atmospheric blurring, using images made with a large-area image slicer. They applied this technique to a series of Mercury sodium observations made in November, 1997 at the McMath-Pierce Solar Telescope. Their technique for producing images from the spectroscopic data provides images of both the sodium emission and of the sunlight reflected from the surface.

  14. Conceptual data modeling of wildlife response indicators to ecosystem change in the Arctic

    USGS Publications Warehouse

    Walworth, Dennis; Pearce, John M.

    2015-01-01

    Large research studies are often challenged to effectively expose and document the types of information being collected and the reasons for data collection across what are often a diverse cadre of investigators of differing disciplines. We applied concepts from the field of information or data modeling to the U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative to prototype an application of information modeling. The USGS CAE initiative is collecting information from marine and terrestrial environments in Alaska to identify and understand the links between rapid physical changes in the Arctic and response of wildlife populations to these ecosystem changes. An associated need is to understand how data collection strategies are informing the overall science initiative and facilitating communication of those strategies to a wide audience. We explored the use of conceptual data modeling to provide a method by which to document, describe, and visually communicate both enterprise and study level data; provide a simple means to analyze commonalities and differences in data acquisition strategies between studies; and provide a tool for discussing those strategies among researchers and managers.

  15. Recent changes in the Arabian Sea ecosystem linked to large-scale climatic events

    NASA Astrophysics Data System (ADS)

    Goes, Joaquim; do Rosario Gomes, Helga; Prabhu Matondkar, Shivprasad; de Rada, Sergio; Chai, Fei; Dwivedi, Rashmin; Thoppil, Prasad; Al-Azri, Adnan; Basu, Subhajit

    2014-05-01

    Between 1994 and 1996, the Arabian Sea became the focus of a multinational effort directed at studying ocean biological and physical processes and their links to the global carbon cycle. The results of this comprehensive, multi-disciplinary effort known as the Joint Global Flux Study (JGOFS) program provided important indications of the role of the reversal of the monsoons and the extremes in wind forcing, in causing the greatest seasonal variability of primary production and vertical flux of carbon observed in any of the world's oceans. Since the end of the JGOFS program, most contemporary shipboard investigations of primary productivity and biogeochemical processes have come mostly from small programmatically focused shipboard cruises that have been regional in scope. On the other hand, most recent large basin-scale studies have relied mainly on coupled physical-biological models and on satellite data. Here we present a synthesis of recent observations from shipboard cruises and satellites, together with modeling studies which highlight the extreme sensitivity of the Arabian Sea ecosystem to climatic events. We posit that the Arabian Sea ecosystem is undergoing rapid change as a result of changes in physical processes tied to climate change.

  16. Acid rain in China. Rapid industrialization has put citizens and ecosystems at risk

    SciTech Connect

    Thorjoern Larssen; Espen Lydersen; Dagang Tang

    2006-01-15

    Acid rain emerged as an important environmental problem in China in the late 1970s. Many years of record economic growth have been accompanied by increased energy demand, greater coal combustion, and larger emissions of pollutants. As a result of significant emissions and subsequent deposition of sulfur, widespread acid rain is observed in southern and southwestern China. In fact, the deposition of sulfur is in some places higher than what was reported from the 'black triangle' in central Europe in the early 1980s. In addition, nitrogen is emitted from agriculture, power production, and a rapidly increasing number of cars. As a result, considerable deposition of pollutants occurs in forested areas previously thought to be pristine. Little is known about the effects of acid deposition on terrestrial and aquatic ecosystems in China. This article presents the current situation and what to expect in the future, largely on the basis of results from a five-year Chinese-Norwegian cooperative project. In the years ahead, new environmental challenges must be expected if proper countermeasures are not put into place. 31 refs., 4 figs.

  17. Centuries of human-driven change in salt marsh ecosystems.

    PubMed

    Gedan, K Bromberg; Silliman, B R; Bertness, M D

    2009-01-01

    Salt marshes are among the most abundant, fertile, and accessible coastal habitats on earth, and they provide more ecosystem services to coastal populations than any other environment. Since the Middle Ages, humans have manipulated salt marshes at a grand scale, altering species composition, distribution, and ecosystem function. Here, we review historic and contemporary human activities in marsh ecosystems--exploitation of plant products; conversion to farmland, salt works, and urban land; introduction of non-native species; alteration of coastal hydrology; and metal and nutrient pollution. Unexpectedly, diverse types of impacts can have a similar consequence, turning salt marsh food webs upside down, dramatically increasing top down control. Of the various impacts, invasive species, runaway consumer effects, and sea level rise represent the greatest threats to salt marsh ecosystems. We conclude that the best way to protect salt marshes and the services they provide is through the integrated approach of ecosystem-based management. PMID:21141032

  18. The Northern Bering Sea: An Arctic Ecosystem in Change

    NASA Astrophysics Data System (ADS)

    Grebmeier, J. M.; Cooper, L. W.

    2004-12-01

    Arctic systems can be rich and diverse habitats for marine life in spite of the extreme cold environment. Benthic faunal populations and associated biogeochemical cycling processes are influenced by sea-ice extent, seawater hydrography (nutrients, salinity, temperature, currents), and water column production. Benthic organisms on the Arctic shelves and margins are long-term integrators of overlying water column processes. Because these organisms have adapted to living at cold extremes, it is reasonable to expect that these communities will be among the most susceptible to climate warming. Recent observations show that Arctic sea ice in the North American Arctic is melting and retreating northward earlier in the season and the timing of these events can have dramatic impacts on the biological system. Changes in overlying primary production, pelagic-benthic coupling, and benthic production and community structure can have cascading effects to higher trophic levels, particularly benthic feeders such as walruses, gray whales, and diving seaducks. Recent indicators of contemporary Arctic change in the northern Bering Sea include seawater warming and reduction in ice extent that coincide with our time-series studies of benthic clam population declines in the shallow northern Bering shelf in the 1990's. In addition, declines in benthic amphipod populations have also likely influenced the movement of feeding gray whales to areas north of Bering Strait during this same time period. Finally a potential consequence of seawater warming and reduced ice extent in the northern Bering Sea could be the northward movement of bottom feeding fish currently in the southern Bering Sea that prey on benthic fauna. This would increase the feeding pressure on the benthic prey base and enhance competition for this food source for benthic-feeding marine mammals and seabirds. This presentation will outline recent biological changes observed in the northern Bering Sea ecosystem as documented in

  19. The quickening pace and widening scope of ecosystem transformation under climate change (Invited)

    NASA Astrophysics Data System (ADS)

    Graumlich, L. J.; Bunn, A. G.

    2013-12-01

    When will we see climate-driven impacts on ecosystems and the associated services they provide to humans? Two large ecosystems stand out as heading towards tipping points: arctic ecosystems, and the forests of western North America. While each ecosystem is structurally distinct (i.e., tundra and sparse boreal forests vs. closed canopy forest) and proximate drivers of change are different (i.e., warming vs. drought), commonalities between them offer insights into what processes lead to the kind of ecosystem changes that have the potential to truly 'tip' into a novel regime. First, scale matters: in both ecosystems the spatial scale of change is unprecedented since the Holocene Climate Optimum more than 5,000 years ago. In the Arctic we see widespread changes in the timing and magnitude of ecosystem productivity, which affects biogeochemical cycling, evapotranspiration, and albedo. In western US forests, large fires have increased in frequency by a factor of 4 over the past few decades, driven in large part by broad-scale, severe droughts. Second, timing is everything: changing phenology is associated with unraveling ecological relationships. In the Arctic we see a reduction of seasonality in temperature and vegetation production equivalent to several degrees of latitudinal shift towards the equator. In western US forests, relatively small advances in the timing of snowmelt are associated with earlier dry down of fine fuels, which, in turn, lengthens the fire season. Finally, and perhaps most importantly, ecosystem change can and will accelerate climate change. This can be seen in high latitude systems, as well as in the American West, as changes in microclimate, albedo, and ecosystem function feed back to atmospheric processes. Such large-scale, abrupt and non-linear changes in ecosystems and the associated provision of ecosystem services are one of the greatest challenges society faces in adapting to climate change.

  20. Physical processes mediating climate change impacts on regional sea ecosystems

    NASA Astrophysics Data System (ADS)

    Holt, J.; Schrum, C.; Cannaby, H.; Daewel, U.; Allen, I.; Artioli, Y.; Bopp, L.; Butenschon, M.; Fach, B. A.; Harle, J.; Pushpadas, D.; Salihoglu, B.; Wakelin, S.

    2014-02-01

    Regional seas are exceptionally vulnerable to climate change, yet are the most directly societally important regions of the marine environment. The combination of widely varying conditions of mixing, forcing, geography (coastline and bathymetry) and exposure to the open-ocean makes these seas subject to a wide range of physical processes that mediates how large scale climate change impacts on these seas' ecosystems. In this paper we explore these physical processes and their biophysical interactions, and the effects of atmospheric, oceanic and terrestrial change on them. Our aim is to elucidate the controlling dynamical processes and how these vary between and within regional seas. We focus on primary production and consider the potential climatic impacts: on long term changes in elemental budgets, on seasonal and mesoscale processes that control phytoplankton's exposure to light and nutrients, and briefly on direct temperature response. We draw examples from the MEECE FP7 project and five regional models systems using ECOSMO, POLCOMS-ERSEM and BIMS_ECO. These cover the Barents Sea, Black Sea, Baltic Sea, North Sea, Celtic Seas, and a region of the Northeast Atlantic, using a common global ocean-atmosphere model as forcing. We consider a common analysis approach, and a more detailed analysis of the POLCOMS-ERSEM model. Comparing projections for the end of the 21st century with mean present day conditions, these simulations generally show an increase in seasonal and permanent stratification (where present). However, the first order (low- and mid-latitude) effect in the open ocean projections of increased permanent stratification leading to reduced nutrient levels, and so to reduced primary production, is largely absent, except in the NE Atlantic. Instead, results show a highly heterogeneous picture of positive and negative change arising from the varying mixing and circulation conditions. Even in the two highly stratified, deep water seas (Black and Baltic Seas) the

  1. Global change accelerates carbon assimilation by a wetland ecosystem engineer

    NASA Astrophysics Data System (ADS)

    Caplan, Joshua S.; Hager, Rachel N.; Megonigal, J. Patrick; Mozdzer, Thomas J.

    2015-11-01

    The primary productivity of coastal wetlands is changing dramatically in response to rising atmospheric carbon dioxide (CO2) concentrations, nitrogen (N) enrichment, and invasions by novel species, potentially altering their ecosystem services and resilience to sea level rise. In order to determine how these interacting global change factors will affect coastal wetland productivity, we quantified growing-season carbon assimilation (≈gross primary productivity, or GPP) and carbon retained in living plant biomass (≈net primary productivity, or NPP) of North American mid-Atlantic saltmarshes invaded by Phragmites australis (common reed) under four treatment conditions: two levels of CO2 (ambient and +300 ppm) crossed with two levels of N (0 and 25 g N added m-2 yr-1). For GPP, we combined descriptions of canopy structure and leaf-level photosynthesis in a simulation model, using empirical data from an open-top chamber field study. Under ambient CO2 and low N loading (i.e., the Control), we determined GPP to be 1.66 ± 0.05 kg C m-2 yr-1 at a typical Phragmites stand density. Individually, elevated CO2 and N enrichment increased GPP by 44 and 60%, respectively. Changes under N enrichment came largely from stimulation to carbon assimilation early and late in the growing season, while changes from CO2 came from stimulation during the early and mid-growing season. In combination, elevated CO2 and N enrichment increased GPP by 95% over the Control, yielding 3.24 ± 0.08 kg C m-2 yr-1. We used biomass data to calculate NPP, and determined that it represented 44%-60% of GPP, with global change conditions decreasing carbon retention compared to the Control. Our results indicate that Phragmites invasions in eutrophied saltmarshes are driven, in part, by extended phenology yielding 3.1× greater NPP than native marsh. Further, we can expect elevated CO2 to amplify Phragmites productivity throughout the growing season, with potential implications including accelerated spread

  2. Effects of Land Use Changes on the Ecosystem Service Values of a Reclamation Farm in Northeast China

    NASA Astrophysics Data System (ADS)

    Hao, Fanghua; Lai, Xuehui; Ouyang, Wei; Xu, Yiming; Wei, Xinfeng; Song, Kaiyu

    2012-11-01

    Intensive agricultural development can change land use, which can further affect regional ecosystem services and functions. With the rapid growth of the population and the national demand for food, the northeast of China, which is located in the high latitudes, has experienced four agricultural developments since the 1950s. The original wetlands of this area were developed for farmland. The evaluation of ecosystem services is conducted to reveal the ecosystem status and variable trends caused by land reclamation. The aim of this study is to provide scientific basis for environmental management and for the sustainable development of agriculture in Northeast China. With GIS-RS technology, a typical farm was chosen to analyze variations in the ecosystem service value in response to land use changes during the study period. The total ecosystem service value of the farm decreased from 7523.10 million Yuan in 1979 to 4023.59 million Yuan in 2009 with an annual rate of -1.6 % due to the decreasing areas of woodland and wetland. The increased areas of cropland, water area and grassland partly offset the loss of the total value, but the loss was still greater than the compensation. Waste treatment and climate regulation were the top two service functions with high service values, contributing to approximately 50 % of the total service value. The spatial difference of the ecosystem service value also was analyzed. The wetlands located in the central and northeastern sections of the farm changed significantly. From the aspect of ecosystem service value, the wetland and water area should be conserved, as they have the highest value coefficients. The accuracy of the value coefficient, however, needs to be studied further in future research.

  3. Assessing ecosystem response to multiple disturbances and climate change in South Africa using ground- and satellite-based measurements and model

    NASA Astrophysics Data System (ADS)

    Kutsch, W. L.; Falge, E. M.; Brümmer, C.; Mukwashi, K.; Schmullius, C.; Hüttich, C.; Odipo, V.; Scholes, R. J.; Mudau, A.; Midgley, G.; Stevens, N.; Hickler, T.; Scheiter, S.; Martens, C.; Twine, W.; Iiyambo, T.; Bradshaw, K.; Lück, W.; Lenfers, U.; Thiel-Clemen, T.; du Toit, J.

    2015-12-01

    Sub-Saharan Africa currently experiences rapidly growing human population, intrinsically tied to substantial changes in land use on shrubland, savanna and mixed woodland ecosystems due to over-exploitation. Significant conversions driving degradation, affecting fire frequency and water availability, and fueling climate change are expected to increase in the immediate future. However, measured data of greenhouse gas emissions as affected by land use change are scarce to entirely lacking from this region. The project 'Adaptive Resilience of Southern African Ecosystems' (ARS AfricaE) conducts research and develops scenarios of ecosystem development under climate change, for management support in conservation or for planning rural area development. This will be achieved by (1) creation of a network of research clusters (paired sites with natural and altered vegetation) along an aridity gradient in South Africa for ground-based micrometeorological in-situ measurements of energy and matter fluxes, (2) linking biogeochemical functions with ecosystem structure, and eco-physiological properties, (3) description of ecosystem disturbance (and recovery) in terms of ecosystem function such as carbon balance components and water use efficiency, (4) set-up of individual-based models to predict ecosystem dynamics under (post) disturbance managements, (5) combination with long-term landscape dynamic information derived from remote sensing and aerial photography, and (6) development of sustainable management strategies for disturbed ecosystems and land use change. Emphasis is given on validation (by a suite of field measurements) of estimates obtained from eddy covariance, model approaches and satellite derivations.

  4. The provision of ecosystem services in response to global change: Evidences and applications.

    PubMed

    Lafortezza, Raffaele; Chen, Jiquan

    2016-05-01

    As a consequence of the global increase in economic and societal prosperity, ecosystems and natural resources have been substantially exploited, degraded, or even destroyed in the last century. To prevent further deprivation of the quality of ecosystems, the ecosystem services concept has become a central issue in environmental studies. A growing number of environmental agencies and organizations worldwide are now embracing integrated approaches to plan and manage ecosystems, sharing a goal to maintain the long-term provision of ecosystem services for sustainability. A daunting challenge in this process is to move from general pronouncements about the tremendous benefits that ecosystems provide to society to defensible assessments of their services. In other words, we must move beyond the scientific evidences of the ecosystem services concept to its practical applications. In this work, we discuss the theoretical foundations and applications of ecosystem services with a focus on the assessment of ecosystem service trade-offs and synergies at various spatial and temporal scales. Here, we offer examples of the main factors related to land use management that may affect the provision of ecosystem services and provide direction for future research on ecosystem services and related nature-based solutions. We also provide a briefing on the major topics covered in this Special Issue, which focuses on the provision of ecosystem services in the context of global change. PMID:26944091

  5. Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

    USGS Publications Warehouse

    Wolken, Jane M.; Hollingsworth, Teresa N.; Rupp, T. Scott; Chapin, Stuart III; Trainor, Sarah F.; Barrett, Tara M.; Sullivan, Patrick F.; McGuire, A. David; Euskirchen, Eugénie S.; Hennon, Paul E.; Beever, Erik A.; Conn, Jeff S.; Crone, Lisa K.; D'Amore, David V.; Fresco, Nancy; Hanley, Thomas A.; Kielland, Knut; Kruse, James J.; Patterson, Trista; Schuur, Edward A.G.; Verbyla, David L.; Yarie, John

    2011-01-01

    The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer- to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral- and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates

  6. HYDROLOGIC THRESHOLDS FOR BIODIVERSITY IN SEMIARID RIPARIAN ECOSYSTEMS: IMPORTANCE OF CLIMATE CHANGE AND VARIABILITY

    EPA Science Inventory

    Riparian ecosystems of the arid and semiarid Southwest are linear corridors of high productivity and diversity. These ecosystems are sensitive to even small changes in the riparian water balance, with sharp changes in vegetation as streams become intermittent and as groundwate...

  7. CHARACTERIZE INTERACTIONS BETWEEN ECOSYSTEM FUNCTIONING AND CHANGES IN CLIMATE, UV, AND LAND USE

    EPA Science Inventory

    Assessments of the long-term impacts of global changes in climate, ultraviolet (UV) radiation and land use on ecosystems require scientific data, concepts and models that describe the responses of ecosystem health to stresses related to the changes as well as information and mode...

  8. The Role of Remote Sensing in Modeling Landscape Change and Its Associated Carbon Cycle Impacts Across Terrestrial Arctic Ecosystems

    NASA Astrophysics Data System (ADS)

    Hayes, D. J.; Goswami, S.; Jones, B. M.; Grosse, G.; Balser, A.; Wullschleger, S. D.

    2014-12-01

    Terrestrial ecosystems across the circumpolar Arctic region are undergoing unprecedented changes in structure and function as a result of rapid climate warming. Such changes have substantially altered energy, water and biogeochemical cycling in these regions, which has important global-scale consequences for climate and society. Recognizing the vulnerability of these ecosystems to change, scientists and decision-makers have identified a critical need for research that employs existing and new remote sensing technologies and methodologies to observe, monitor and understand changes in Arctic ecosystems. The unique capabilities provided by remote sensing imagery and data products have allowed us novel views of ecosystems and their dynamics over multiple scales in time and space across all regions of the globe. Here we offer a synthetic discussion of the recent and emerging science focused on understanding the dynamic landscape processes in Arctic terrestrial ecosystems using a variety of remotely-sensed information collected from passive and active sensors on ground-, aircraft- and satellite- based platforms. To consider the evolution of these technologies, methods and applications over recent decades, we look at key examples from the scientific literature that range from the use of radar sensors for local-scale characterization of active layer dynamics to the circumpolar-scale assessment of changes in vegetation productivity using long-term records of optical satellite imagery. This discussion has a particular focus on the use of remotely sensed data and products to parameterize, drive, evaluate and benchmark the modeling of Arctic ecosystem processes. We use these examples to demonstrate the opportunities for model-data integration, as well as to highlight the challenges of remote sensing studies in northern high latitude regions.

  9. Centuries of Human-Driven Change in Salt Marsh Ecosystems

    NASA Astrophysics Data System (ADS)

    Gedan, K. Bromberg; Silliman, B. R.; Bertness, M. D.

    2009-01-01

    Salt marshes are among the most abundant, fertile, and accessible coastal habitats on earth, and they provide more ecosystem services to coastal populations than any other environment. Since the Middle Ages, humans have manipulated salt marshes at a grand scale, altering species composition, distribution, and ecosystem function. Here, we review historic and contemporary human activities in marsh ecosystems—exploitation of plant products; conversion to farmland, salt works, and urban land; introduction of non-native species; alteration of coastal hydrology; and metal and nutrient pollution. Unexpectedly, diverse types of impacts can have a similar consequence, turning salt marsh food webs upside down, dramatically increasing top down control. Of the various impacts, invasive species, runaway consumer effects, and sea level rise represent the greatest threats to salt marsh ecosystems. We conclude that the best way to protect salt marshes and the services they provide is through the integrated approach of ecosystem-based management.

  10. [Impact of global climate change on agro-ecosystem: a review].

    PubMed

    Xiao, Guo-Ju; Zhang, Qiang; Wang, Jing

    2007-08-01

    In global climate change, the most important ecological factors influencing agricultural production and agro-ecosystem are elevated atmospheric CO2 concentration, enhanced air temperature, and changed precipitation, which mainly exert on crop output, crop growth, diseases and pests, agricultural water resources, and structure and function of agro-ecosystem. In past decades, global climate change already made great influences on our agriculture and agro-ecosystem, especially the agricultural production in arid regions of North China, and many of the influences were negative or adverse. This paper summarized the impact of global climate change on agricultural water resources, soil nutrients, crop growth and development, diseases and pests, weeds, food safety, and structure and function of agro-ecosystem. Aiming at the challenges brought about by the global climate change to the agricultural production and agro-ecosystem in China in 21st century, the key points and difficulties in future research were put forward. PMID:17974260

  11. Assessing significant geomorphic changes and effectiveness of dynamic restoration in a coastal dune ecosystem

    NASA Astrophysics Data System (ADS)

    Walker, Ian J.; Eamer, Jordan B. R.; Darke, Ian B.

    2013-10-01

    A shift from restoring coastal dunes as stabilized landscapes toward more morphodynamic ecosystems is underway. This paper uses results from a recent case study where invasive vegetation was removed from a coastal dune complex in western Canada as a first step in a dynamic ecosystem restoration project. Spatial statistical methods, used in the natural sciences to quantify patterns of significant spatial-temporal changes, are reviewed and the local Moran's Ii spatial autocorrelation statistic is explored for detecting and assessing significant changes. Cluster maps of positive (depositional) and negative (erosional) changes were used to derive statistically significant volumetric changes within discrete geomorphic units (beach, foredune, transgressive dune) over one year following vegetation removal. All units experienced net increases in sediment budgets compared to a pre-restoration surface. The beach experienced the highest episodic erosion and volumetric change and greatest net annual sediment budget. Compared to the beach, the annual sediment budget of the foredune was 19% whereas the transgressive dune was 33%. The foredune recovered rapidly to initial erosion during restoration and subsequent natural events with consistently positive sediment volumes and attained a form similar to that pre-restoration. Aeolian deflation and sand bypassing through the foredune was greatest in the two months following vegetation removal and peak accretion in the transgressive dune resulted from depositional lobes extending from the foredune, smaller dunes migrating within the complex, and growth of a precipitation ridge along the eastern margin. Several methodological and logistical considerations for detecting significant change in dynamic dune landscapes are discussed including sampling strategy design, data normalization and control measures, and incorporating uncertainty and inherent spatial relations within acquired datasets to ensure accuracy and comparability of results

  12. Recent and widespread rapid morphological change in rodents.

    PubMed

    Pergams, Oliver R W; Lawler, Joshua J

    2009-01-01

    In general, rapid morphological change in mammals has been infrequently documented. Examples that do exist are almost exclusively of rodents on islands. Such changes are usually attributed to selective release or founder events related to restricted gene flow in island settings. Here we document rapid morphological changes in rodents in 20 of 28 museum series collected on four continents, including 15 of 23 mainland sites. Approximately 17,000 measurements were taken of 1302 rodents. Trends included both increases and decreases in the 15 morphological traits measured, but slightly more trends were towards larger size. Generalized linear models indicated that changes in several of the individual morphological traits were associated with changes in human population density, current temperature gradients, and/or trends in temperature and precipitation. When we restricted these analyses to samples taken in the US (where data on human population trends were presumed to be more accurate), we found changes in two additional traits to be positively correlated with changes in human population density. Principle component analysis revealed general trends in cranial and external size, but these general trends were uncorrelated with climate or human population density. Our results indicate that over the last 100+ years, rapid morphological change in rodents has occurred quite frequently, and that these changes have taken place on the mainland as well as on islands. Our results also suggest that these changes may be driven, at least in part, by human population growth and climate change. PMID:19649284

  13. Rapid toxicity assessment of sediments from estuarine ecosystems: A new tandem in vitro testing approach

    USGS Publications Warehouse

    Johnson, B.T.; Long, E.R.

    1998-01-01

    Microtox?? and Mutatox?? were used to evaluate the acute toxicity and genotoxicity, respectively, of organic sediment extracts from Pensacola Bay and St. Andrew Bay, two estuaries that cover about 273 and 127 km2, respectively, along the Gulf coast of Florida, USA. The sensitivity and selectivity of these two bioluminescent toxicity assays were demonstrated in validation studies with over 50 pesticides, genotoxins, and industrial pollutants, both as single compounds and in complex mixtures. The 50% effective concentration (EC50) values of insecticides, petroleum products, and polychlorinated biphenyls determined by Microtox all tended to group around the mean EC50 value of 1.2 (0.8) mg/L. The polycyclic aromatic hydrocarbon sensitivity of Mutatox was in general similar to that reported in the Ames test. Surficial sediment samples were collected, extracted with dichloromethane, evaporated and concentrated under nitrogen, dissolved in dimethyl sulfoxide, assayed for acute toxicity and genotoxicity, and compared with reference sediments. Samples with low EC50 values, and determined to be genotoxic, were detected in Massalina Bayou, Watson Bayou, East Bay, and St. Andrew Bay-East in St. Andrew Bay as well as Bayou Grande, Bayou Chico, and Bayou Texar in Pensacola Bay. An overview of these data sets analyzed by Spearman rank correlation showed a significant correlation between acute toxicity and genotoxicity (p < 0.05). Microtox and Mutatox in tandem was a sensitive, cost-effective, and rapid (<24 h) screening tool that identified troublesome areas of pollution and assessed the potential sediment toxicity of lipophilic contaminants in aquatic ecosystems.

  14. CLIMAITE - a three factor climate change ecosystem manipulation experiment.

    NASA Astrophysics Data System (ADS)

    Mikkelsen, T. N.; Beier, C.; Albert, K.; Ro-Poulsen, H.

    2007-12-01

    The Danish multi factorial climate change effects on vegetation experiment (Climaite) have now been conducted for two years on semi-natural grassland. The day time [CO2], night time temperature and precipitation (drought) have been altered, according to a regional climate change model for the year 2075, in a full factorial split plot design. The manipulated area for each treatment is 7 m2 and it is replicated 6 times. The CO2 and temperature treatments have been conducted continuously except for periods with snow cover. The CO2 is enhanced to 510 ppm via a FACE system based on concentrated CO2 released upwind under pressure. The control of the [CO2] varies with wind speed and irradiation, but during 50 percent of the fumigation period the target concentration was kept within +/-5 percent. The temperature treatment is conducted via infrared reflective curtains covering the plots during night time, and the warming of plants and soil depends of the day irradiation, night time wind speed and factors related to seasonality. In general, the air temperature is increased during night time with 1-2 C° and negligible during the day. The soil temperature in 5 cm depth is enhanced to 0.3 - 0.6 C° during night and day. The artificial summer droughts lasted about one month and differences in soil water content were developed over time. By the end of the treatment the èv content in the soil was as low as 0.06 m3 m-3 compared to 0.20 m3 m-3 in the control. Numerous physical and biological parameters in the grassland ecosystem have been measured and several are responding to the changed environment. After 9 months of exposure enhanced [CO2] stimulated the net photosynthesis (based on dry weight) in both of the domination plant species Calluna Vulgaris and Deschampsia flexuosa. When the plants were exposed to short term saturated [CO2] during gasexchange measurements the long term CO2 treated plants also had the highest photosynthesis rate, meaning that the plants were not

  15. Ecosystem Services and Climate Change Considerations for Long Island (NY) Planning Post Hurricane Sandy

    EPA Science Inventory

    Freshwater habitats provide fishable, swimmable and drinkable resources and are a nexus of geophysical and biological processes. These processes in turn influence the persistence and sustainability of populations, communities and ecosystems. Climate change and landuse change enco...

  16. Ecosystem Change in California Grasslands: Impacts of Species Invasion

    NASA Astrophysics Data System (ADS)

    Koteen, L. E.; Harte, J.; Baldocchi, D. D.

    2009-12-01

    Grassland ecosystems of California have undergone dramatic changes, resulting in the almost complete replacement of native perennial grasses by non-native annuals across millions of hectares of grassland habitat. Our research investigates the effects of this community shift on carbon, water and energy cycles at two sites in northern coastal California. Our goal was to understand how changes to California’s grasslands have affected climate through 1. shifting the balance of carbon storage between terrestrial stocks and the atmosphere, and 2. altering the water and energy regimes that heat or cool the earth's surface. To compare the processes that govern material exchange before and after annual grass invasion, we made use of sites where native vegetation is found adjacent to locations that have undergone non-native invasion. In plots of each vegetation type, we monitored whole plant productivity, root and litter decay rates and soil respiration, as well as soil climatic controls on these processes. At one site, we also measured surface albedo and the components of the surface energy balance in each grass community, using the surface renewal method. Although seemingly subtle, the shift in California grassland communities from native perennial to non-native annual grass dominance has had profound consequences for ecosystem biogeochemical, radiative and hydrological cycles. Soil carbon storage was found to be significantly greater in native perennial grass communities. Across both study sites, we found that non-native grass invasion has resulted in the transfer of from 3 to 6 tons of carbon per hectare from the soil to the atmosphere, dependent on site and species. A soil density fractionation and a radiocarbon analysis also revealed the carbon to be more recalcitrant in native grass dominated locations. The primary plant traits that help explain why soil carbon losses follow annual grass invasion are: 1. differences between annual and perennial grasses in above

  17. Will Global Change Effect Primary Productivity in Coastal Ecosystems?

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.; Peterson, David L. (Technical Monitor)

    1997-01-01

    Algae are the base of coastal food webs because they provide the source of organic carbon for the remaining members of the community. Thus, the rate that they produce organic carbon to a large extent controls the productivity of the entire ecosystem. Factors that control algal productivity range from the physical (e.g., temperature, light), chemical (e.g., nutrient levels) to the biological (e.g., grazing). Currently, levels of atmospheric carbon dioxide surficial fluxes of ultraviolet radiation are rising. Both of these environmental variables can have a profound effect on algal productivity. Atmospheric carbon dioxide may increase surficial levels of dissolved inorganic carbon. Our laboratory and field studies of algal mats and phytoplankton cultures under ambient and elevated levels of pCO2 show that elevated levels of inorganic carbon can cause an increase in photosynthetic rates. In some cases, this increase will cause an increase in phytoplankton numbers. There may be an increase in the excretion of fixed carbon, which in turn may enhance bacterial productivity. Alternatively, in analogy with studies on the effect of elevated pCO2 on plants, the phytoplankton could change their carbon to nitrogen ratios, which will effect the feeding of the planktonic grazers. The seasonal depletion of stratospheric ozone has resulted in elevated fluxes of UVB radiation superimposed on the normal seasonal variation. Present surface UV fluxes have a significant impact on phytoplankton physiology, including the inhibition of the light and dark reactions of photosynthesis, inhibition of nitrogenase activity, inhibition of heterocyst formation, reduction in motility, increased synthesis of the UV-screening pigment scytonemin, and mutation. After reviewing these issues, recent work in our lab on measuring the effect of UV radiation on phytoplankton in the San Francisco Bay Estuary will be presented.

  18. Exploring Pacific Northwest ecosystem resilience: packaging climate change science for federal managers

    NASA Astrophysics Data System (ADS)

    Bachelet, D. M.

    2014-12-01

    Climate change is projected to jeopardize ecosystems in the Pacific Northwest. Managing ecosystems for future resilience requires collaboration, innovation and communication. The abundance of data and documents describing the uncertainty around both climate change projections and impacts has become challenging to managers who have little funding and limited time to digest and incorporate these materials into planning and implementation documents. We worked with US Forest Service and BLM managers to help them develop vulnerability assessments and identify on-the-ground strategies to address climate change challenges on the federal lands in northwest Oregon (Siuslaw, Willamette and Mt. Hood National Forests; Eugene and Salem BLM Districts). We held workshops to promote dialogue about climate change, which were particularly effective in fostering discussions between the managers who often do not have the time to share their knowledge and compare experiences across administrative boundaries. We used the Adaptation for Conservation Targets (ACT) framework to identify measurable management objectives and rapidly assess local vulnerabilities. We used databasin.org to centralize usable information, including state-of-the-art CMIP5 climate projections, for the mandated assessments of vulnerability and resilience. We introduced participants to a decision support framework providing opportunities to develop more effective adaptation strategies. We built a special web page to hold the information gathered at the workshops and provide easy access to climate change information. We are now working with several Landscape Conservation Cooperatives (LCCs) to design gateways - conservation atlases - to their relevant data repositories on databasin.org and working with them to develop web tools that can provide usable information for their own vulnerability assessments.

  19. Pattern formation--A missing link in the study of ecosystem response to environmental changes.

    PubMed

    Meron, Ehud

    2016-01-01

    Environmental changes can affect the functioning of an ecosystem directly, through the response of individual life forms, or indirectly, through interspecific interactions and community dynamics. The feasibility of a community-level response has motivated numerous studies aimed at understanding the mutual relationships between three elements of ecosystem dynamics: the abiotic environment, biodiversity and ecosystem function. Since ecosystems are inherently nonlinear and spatially extended, environmental changes can also induce pattern-forming instabilities that result in spatial self-organization of life forms and resources. This, in turn, can affect the relationships between these three elements, and make the response of ecosystems to environmental changes far more complex. Responses of this kind can be expected in dryland ecosystems, which show a variety of self-organizing vegetation patterns along the rainfall gradient. This paper describes the progress that has been made in understanding vegetation patterning in dryland ecosystems, and the roles it plays in ecosystem response to environmental variability. The progress has been achieved by modeling pattern-forming feedbacks at small spatial scales and up-scaling their effects to large scales through model studies. This approach sets the basis for integrating pattern formation theory into the study of ecosystem dynamics and addressing ecologically significant questions such as the dynamics of desertification, restoration of degraded landscapes, biodiversity changes along environmental gradients, and shrubland-grassland transitions. PMID:26529391

  20. Biophysical controls on accretion and elevation change in Caribbean mangrove ecosystems

    USGS Publications Warehouse

    McKee, K.L.

    2011-01-01

    Habitat stability of coastal ecosystems, such as marshes and mangroves, depends on maintenance of soil elevations relative to sea level. Many such systems are characterized by limited mineral sedimentation and/or rapid subsidence and are consequently dependent upon accumulation of organic matter to maintain elevations. However, little field information exists regarding the contribution of specific biological processes to vertical accretion and elevation change. This study used biogenic mangrove systems in carbonate settings in Belize (BZ) and southwest Florida (FL) to examine biophysical controls on elevation change. Rates of elevation change, vertical accretion, benthic mat formation, and belowground root accumulation were measured in fringe, basin, scrub, and dwarf forest types plus a restored forest. Elevation change rates (mm yr-1) measured with Surface Elevation Tables varied widely: BZ-Dwarf (-3.7), BZ-Scrub (-1.1), FL-Fringe (0.6), FL-Basin (2.1), BZ-Fringe (4.1), and FL-Restored (9.9). Root mass accumulation varied across sites (82-739 g m-2 yr-1) and was positively correlated with elevation change. Root volumetric contribution to vertical change (mm yr-1) was lowest in BZ-Dwarf (1.2) and FL-Fringe (2.4), intermediate in FL-Basin (4.1) and BZ-Scrub (4.3), and highest in BZ-Fringe (8.8) and FL-Restored (11.8) sites. Surface growth of turf-forming algae, microbial mats, or accumulation of leaf litter and detritus also made significant contributions to vertical accretion. Turf algal mats in fringe and scrub forests accreted faster (2.7 mm yr-1) than leaf litter mats in basin forests (1.9 mm yr-1), but similarly to microbial mats in dwarf forests (2.1 mm yr-1). Surface accretion of mineral material accounted for only 0.2-3.3% of total vertical change. Those sites with high root contributions and/or rapid growth of living mats exhibited an elevation surplus (+2 to +8 mm yr-1), whereas those with low root inputs and low (or non-living) mat accumulation showed an

  1. Biophysical controls on accretion and elevation change in Caribbean mangrove ecosystems

    NASA Astrophysics Data System (ADS)

    McKee, Karen L.

    2011-03-01

    Habitat stability of coastal ecosystems, such as marshes and mangroves, depends on maintenance of soil elevations relative to sea level. Many such systems are characterized by limited mineral sedimentation and/or rapid subsidence and are consequently dependent upon accumulation of organic matter to maintain elevations. However, little field information exists regarding the contribution of specific biological processes to vertical accretion and elevation change. This study used biogenic mangrove systems in carbonate settings in Belize (BZ) and southwest Florida (FL) to examine biophysical controls on elevation change. Rates of elevation change, vertical accretion, benthic mat formation, and belowground root accumulation were measured in fringe, basin, scrub, and dwarf forest types plus a restored forest. Elevation change rates (mm yr -1) measured with Surface Elevation Tables varied widely: BZ-Dwarf (-3.7), BZ-Scrub (-1.1), FL-Fringe (0.6), FL-Basin (2.1), BZ-Fringe (4.1), and FL-Restored (9.9). Root mass accumulation varied across sites (82-739 g m -2 yr -1) and was positively correlated with elevation change. Root volumetric contribution to vertical change (mm yr -1) was lowest in BZ-Dwarf (1.2) and FL-Fringe (2.4), intermediate in FL-Basin (4.1) and BZ-Scrub (4.3), and highest in BZ-Fringe (8.8) and FL-Restored (11.8) sites. Surface growth of turf-forming algae, microbial mats, or accumulation of leaf litter and detritus also made significant contributions to vertical accretion. Turf algal mats in fringe and scrub forests accreted faster (2.7 mm yr -1) than leaf litter mats in basin forests (1.9 mm yr -1), but similarly to microbial mats in dwarf forests (2.1 mm yr -1). Surface accretion of mineral material accounted for only 0.2-3.3% of total vertical change. Those sites with high root contributions and/or rapid growth of living mats exhibited an elevation surplus (+2 to +8 mm yr -1), whereas those with low root inputs and low (or non-living) mat accumulation

  2. Environmental consequences of geochemical change in hot spring ecosystems

    NASA Astrophysics Data System (ADS)

    Havig, J. R.; Shock, E.

    2010-12-01

    ), and the sulfate concentration decreased by 36 % (from 255 to 166 ppm). The changes suggest an increased liquid-phase hydrothermal input (increasing Cl) coupled with a decreased gas-phase input (sulfide, oxidized to sulfate). Many reactions that do not yield energy at pH = 3.7 become energy yielding at pH = 7.6, including methanogenesis from CO or CO2 coupled with H2S oxidation to pyrite. These examples from the geochemistry of fluctuating hot spring systems illustrate how predictions can be made about dynamic changes in microbial ecosystems that can be tested by molecular methods.

  3. The human dimensions of global environmental change: Ecosystem services, resilience, and governance

    NASA Astrophysics Data System (ADS)

    Rechkemmer, A.; von Falkenhayn, L.

    2009-02-01

    Global environmental change affects all societies and their environments at various spatial and temporal scales. The linking of natural ecosystems to social ones is of central importance for the analysis, mitigation of and adaptation to any action or issue related to sustainability and global change. When examining the human dimensions of environmental change, the study of ecosystem services illustrates the strong interlinkages existing between both socio-ecological systems and global change. Ecosystem services are inextricably linked to human well-being and play a central role in sustainable adaptation strategies. Environmental impact of global change can both add to social vulnerability and change resilience by altering the supply of ecosystem services and the trade-offs which can occur. It is when examining such phenomena that the importance and abilities of governance systems to shape change and responses are seen.

  4. Impacts of Global Change Scenarios on Ecosystem Services from the World's Rivers

    NASA Astrophysics Data System (ADS)

    Vorosmarty, C. J.

    2012-12-01

    Water is an essential building block of the Earth system and is critical to human prosperity. At the same time, humans are rapidly embedding themselves into the basic character of the water cycle without full knowledge of the consequences. Major sources of water system change include mismanagement and overuse, river flow distortion, pollution, watershed disturbance, invasive species, and greenhouse warming. A pandemic syndrome of risk to rivers-the chief renewable water supply supporting humans and aquatic biodiversity—is evident at the fully global scale, with a costly price-tag ($0.5Tr/yr) required for engineering-based management solutions aimed at fixing rather than preventing problems before they arise. A new project funded under the NSF's Coupled Natural-Human Systems program aims to improve our current understanding of the geography of water-related ecosystem services, accounting for both biophysical and economic controls on these services, and assessing how new management strategies could enhance the resiliency of the global water system over a 100-year time horizon. Within the context of the many sources of threat summarized above, we see the coupling of human-natural systems to be intrinsic to the science at hand, through which we have formulated our central hypothesis: Human-derived stresses imposed on the global water system will intensify over the 21st century, reducing water-related freshwater ecosystem provisioning and supporting services, increasing the costs of their remediation, limiting and shifting the geography of key economic sector outputs, and threatening biodiversity. Addressing this hypothesis has forced a substantial advancement in current capabilities, namely to (i) extend analysis into the 21st century through scenarios, (ii) develop explicit links to freshwater ecosystem services, (iii) assess how the condition of ecosystem services influences the world economy through individual sectors (food, energy, domestic water supply

  5. A novel sensor platform for the rapid hydraulic characterisation of freshwater ecosystems

    NASA Astrophysics Data System (ADS)

    Kriechbaumer, Thomas; Blackburn, Kim; Breckon, Toby; Gill, Andrew; Everard, Nick; Wright, Ros; Rivas Casado, Monica

    2014-05-01

    The spatially explicit quantification of hydraulic features provides valuable information for the physical habitat assessment of freshwater ecosystems. Collection of data on water velocities and depths using in-situ current meters or acoustic sensors on tethered boats is time-consuming and requires good site accessibility. Moreover, on smaller rivers precise spatial data referencing can be challenging, as river bank vegetation can block sky view to navigation satellites over a considerable proportion of the water surface. This paper describes the development and testing of a new small sized remote control sensor platform and a novel approach to spatial data referencing based on computer vision to enable the rapid hydraulic characterisation of habitats in small rivers. It highlights the manifold opportunities that recent achievements in the disciplines of computer science and electronics can create for the environmental sciences. The platform carries an acoustic Doppler current profiler (ADCP) to rapidly collect large amounts of data on water velocities and river depths, from which the spatial and temporal water velocity distributions can be derived. The 1.30m long and 0.60m wide platform hull has been designed to enable single person deployment. Platform pitch and roll magnitudes and periods are quantified at a frequency of 512Hz through a low-cost inertial measurement unit on board, allowing the quantification of the errors that these platform motions can cause in the ADCP data. Jet propulsion and a tail thruster ensure high manoeuvrability, minimum draught operation and greater safety than propellers. An on-board Raspberry Pi computer enables time-synchronised logging of data from a GPS unit, the ADCP and further sensors that may be added to the platform. Real-time serial communication between the Raspberry Pi and the embedded propulsion system control (an Arduino Uno microcontroller) builds the basis for future platform autonomy. This can enable the autonomous

  6. Monitoring of rapid land cover changes in eastern Japan using Terra/MODIS data

    NASA Astrophysics Data System (ADS)

    Harada, I.; Hara, K.; Park, J.; Asanuma, I.; Tomita, M.; Hasegawa, D.; Short, K.; Fujihara, M.,

    2015-04-01

    Vegetation and land cover in Japan are rapidly changing. Abandoned farmland in 2010, for example, was 396,000 ha, or triple that of 1985. Efficient monitoring of changes in land cover is vital to both conservation of biodiversity and sustainable regional development. The Ministry of Environment is currently producing 1/25,000 scale vegetation maps for all of Japan, but the work is not yet completed. Traditional research is time consuming, and has difficulty coping with the rapid nature of change in the modern world. In this situation, classification of various scale remotely sensed data can be of premier use for efficient and timely monitoring of changes in vegetation.. In this research Terra/MODIS data is utilized to classify land cover in all of eastern Japan. Emphasis is placed on the Tohoku area, where large scale and rapid changes in vegetation have occurred in the aftermath of the Great Eastern Japan Earthquake of 11 March 2011. Large sections of coastal forest and agricultural lands, for example, were directly damaged by the earthquake or inundated by subsequent tsunami. Agricultural land was also abandoned due to radioactive contamination from the Fukushima nuclear power plant accident. The classification results are interpreted within the framework of a Landscape Transformation Sere model developed by Hara et al (2010), which presents a multi-staged pattern for tracking vegetation changes under successively heavy levels of human interference. The results of the research will be useful for balancing conservation of biodiversity and ecosystems with the needs for regional redevelopment.

  7. Evidence from 12-year study links ecosystem changes in the Gulf of Maine with climate change

    USGS Publications Warehouse

    Aiken, George R.; Huntington, Thomas G.; Balch, William; Drapeau, David; Bowler, Bruce

    2012-01-01

    Investigators at the Bigelow Laboratory for Ocean Sciences (East Boothbay, Maine) and the U.S. Geological Survey collaborated to study ecosystem changes in the Gulf of Maine. As part of the Gulf of Maine North Atlantic Time Series (GNATS), a comprehensive long-term study of hydrographic, biological, optical and chemical properties, multiple cruises have been conducted each year since 2001 by using a portable laboratory aboard different vessels (figure 1) and occasionally a remotely controlled glider (figure 2). Data collected during these cruises, when analyzed within the context of a century of climatological and streamflow data, document changes in temperature, salinity, and coastal ocean productivity that appear to be related to recent increases in precipitation and streamflow. These results are evidence of a link between changing hydrologic conditions on land and changes in coastal ocean productivity.

  8. USING FISHER INFORMATION TO DETECT GRADUAL AND RAPID ECOSYSTEM REGIME SHIFTS

    EPA Science Inventory

    As ecosystems experience perturbations of varying regularity and intensity, they may either remain within the state space neighborhood of the current regime, or "flip" into the neighborhood of a regime with different characteristics. Although the possibility of such regime shifts...

  9. Implementing Ecosystem Scale Change on the Trinity River, CA

    NASA Astrophysics Data System (ADS)

    Krause, A. F.

    2005-12-01

    The Trinity River is located in far northern California and is the largest tributary to the Klamath River. Trinity Dam was constructed in 1964 by the U.S. Bureau of Reclamation as part of the Central Valley Project to enhance water supply in the Sacramento River Basin through an out-of-basin transfer from the Trinity River. Up to 90 percent of the average annual water yield of the Trinity River has been diverted since construction of Trinity Dam. Flow regulation and the downstream sediment deficit caused by dam operations has created significant changes in the downstream fluvial geomorphology and temperature regime, causing a 50 to 90 percent decline in salmonid populations. The Trinity River Restoration Program is legally mandated to restore and maintain the natural production of salmon and steelhead on the Trinity River. Through nearly two decades of scientific study it was recognized that the fishery restoration is dependant on restoring the attributes of a natural alluvial river. The restoration strategy does not strive to recreate pre-dam conditions; rather, to create a smaller, dynamic alluvial channel exhibiting all the characteristics of the pre-dam river but at a smaller scale. This strategy is intended to best achieve the restoration goals and maintain the purpose and use of the Trinity Dam water supply diversion project. The December 2000 Record of Decision outlines the restoration plan and includes: 1) Flow management to restore geomorphic and riparian processes 2) Flow management for temperature and habitat 3) Channel and watershed rehabilitation 4) Fine and coarse sediment management 5) Adaptive environmental assessment and management Adaptive management requires evaluation of ecosystem response and predictive modeling on an annual time scale to inform annual management decisions. The scientific challenge is to link management actions (flow releases, bank rehabilitation projects, coarse sediment augmentation) to geomorphic and riparian processes, and

  10. Migration as an Agent of Change in Caribbean Island Ecosystems.

    ERIC Educational Resources Information Center

    Marshall, Dawn

    1982-01-01

    There is need to assess the impact of migration on the Caribbean ecosystems. As a 150-year-old institution, emigration is related to the carrying capacity of the islands and the need to export the surplus population when capacity is threatened. Emigration, however, is a deterrent to development and individual independence. (KC)

  11. Climate change and potential reversal of regime shifts in desrt ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Globally, regime shifts from grasslands to shrublands (i.e., desertification) in arid and semiarid ecosystems are thought to be irreversible, similar to state changes in other ecosystems. The consequences of desertification, including loss of soil and nutrients to wind and water erosion, reductions ...

  12. The changing landscape: ecosystem responses to urbanization and pollution across climatic and societal gradients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Urbanization alters both biotic and abiotic ecosystem properties within, surrounding and even at great distances from urban areas. This creates research challenges and environmental problems at local, regional, and global scales. Ecosystem responses to land changes are complex and interacting, occur...

  13. Tropical land-cover change alters biogeochemical inputs to ecosystems in a Mexican montane landscape.

    PubMed

    Ponette-González, A G; Weathers, K C; Curran, L M

    2010-10-01

    In tropical regions, the effects of land-cover change on nutrient and pollutant inputs to ecosystems remain poorly documented and may be pronounced, especially in montane areas exposed to elevated atmospheric deposition. We examined atmospheric deposition and canopy interactions of sulfate-sulfur (SO4(2-)-S), chloride (Cl-), and nitrate-nitrogen (NO(3-)-N) in three extensive tropical montane land-cover types: clearings, forest, and coffee agroforest. Bulk and fog deposition to clearings was measured as well as throughfall (water that falls through plant canopies) ion fluxes in seven forest and five coffee sites. Sampling was conducted from 2005 to 2008 across two regions in the Sierra Madre Oriental, Veracruz, Mexico. Annual throughfall fluxes to forest and coffee sites ranged over 6-27 kg SO4(2-)-S/ha, 12-69 kg Cl-/ha, and 2-6 kg NO(3-)-N/ha. Sulfate-S in forest and coffee throughfall was higher or similar to bulk S deposition measured in clearings. Throughfall Cl- inputs, however, were consistently higher than Cl- amounts deposited to cleared areas, with net Cl- fluxes enhanced in evergreen coffee relative to semi-deciduous forest plots. Compared to bulk nitrate-N deposition, forest and coffee canopies retained 1-4 kg NO(3-)-N/ha annually, reducing NO(3-)-N inputs to soils. Overall, throughfall fluxes were similar to values reported for Neotropical sites influenced by anthropogenic emissions, while bulk S and N deposition were nine- and eightfold greater, respectively, than background wet deposition rates for remote tropical areas. Our results demonstrate that land-cover type significantly alters the magnitude and spatial distribution of atmospheric inputs to tropical ecosystems, primarily through canopy-induced changes in fog and dry deposition. However, we found that land cover interacts with topography and climate in significant ways to produce spatially heterogeneous patterns of anion fluxes, and that these factors can converge to create deposition hotspots

  14. Social Transitions Cause Rapid Behavioral and Neuroendocrine Changes

    PubMed Central

    Maruska, Karen P.

    2015-01-01

    In species that form dominance hierarchies, there are often opportunities for low-ranking individuals to challenge high-ranking ones, resulting in a rise or fall in social rank. How does an animal rapidly detect, process, and then respond to these social transitions? This article explores and summarizes how these social transitions can rapidly (within 24 h) impact an individual’s behavior, physiology, and brain, using the African cichlid fish, Astatotilapia burtoni, as a model. Male A. burtoni form hierarchies in which a few brightly-colored dominant males defend territories and spawn with females, while the remaining males are subordinate, more drab-colored, do not hold a territory, and have minimal opportunities for reproduction. These social phenotypes are plastic and reversible, meaning that individual males may switch between dominant and subordinate status multiple times within a lifetime. When the social environment is manipulated to create males that either ascend (subordinate to dominant) or descend (dominant to subordinate) in rank, there are rapid changes in behavior, circulating hormones, and levels of gene expression in the brain that reflect the direction of transition. For example, within minutes, males ascending in status show bright coloration, a distinct eye-bar, increased dominance behaviors, activation of brain nuclei in the social behavior network, and higher levels of sex steroids in the plasma. Ascending males also show rapid changes in levels of neuropeptide and steroid receptors in the brain, as well as in the pituitary and testes. To further examine hormone–behavior relationships in this species during rapid social ascent, the present study also measured levels of testosterone, 11-ketotestosterone, estradiol, progestins, and cortisol in the plasma during the first week of social ascent and tested for correlations with behavior. Plasma levels of all steroids were rapidly increased at 30 min after social ascent, but were not correlated

  15. Social Transitions Cause Rapid Behavioral and Neuroendocrine Changes.

    PubMed

    Maruska, Karen P

    2015-08-01

    In species that form dominance hierarchies, there are often opportunities for low-ranking individuals to challenge high-ranking ones, resulting in a rise or fall in social rank. How does an animal rapidly detect, process, and then respond to these social transitions? This article explores and summarizes how these social transitions can rapidly (within 24 h) impact an individual's behavior, physiology, and brain, using the African cichlid fish, Astatotilapia burtoni, as a model. Male A. burtoni form hierarchies in which a few brightly-colored dominant males defend territories and spawn with females, while the remaining males are subordinate, more drab-colored, do not hold a territory, and have minimal opportunities for reproduction. These social phenotypes are plastic and reversible, meaning that individual males may switch between dominant and subordinate status multiple times within a lifetime. When the social environment is manipulated to create males that either ascend (subordinate to dominant) or descend (dominant to subordinate) in rank, there are rapid changes in behavior, circulating hormones, and levels of gene expression in the brain that reflect the direction of transition. For example, within minutes, males ascending in status show bright coloration, a distinct eye-bar, increased dominance behaviors, activation of brain nuclei in the social behavior network, and higher levels of sex steroids in the plasma. Ascending males also show rapid changes in levels of neuropeptide and steroid receptors in the brain, as well as in the pituitary and testes. To further examine hormone-behavior relationships in this species during rapid social ascent, the present study also measured levels of testosterone, 11-ketotestosterone, estradiol, progestins, and cortisol in the plasma during the first week of social ascent and tested for correlations with behavior. Plasma levels of all steroids were rapidly increased at 30 min after social ascent, but were not correlated with

  16. Method for producing rapid pH changes

    DOEpatents

    Clark, John H.; Campillo, Anthony J.; Shapiro, Stanley L.; Winn, Kenneth R.

    1981-01-01

    A method of initiating a rapid pH change in a solution by irradiating the solution with an intense flux of electromagnetic radiation of a frequency which produces a substantial pK change to a compound in solution. To optimize the resulting pH change, the compound being irradiated in solution should have an excited state lifetime substantially longer than the time required to establish an excited state acid-base equilibrium in the solution. Desired pH changes can be accomplished in nanoseconds or less by means of picosecond pulses of laser radiation.

  17. Method for producing rapid pH changes

    DOEpatents

    Clark, J.H.; Campillo, A.J.; Shapiro, S.L.; Winn, K.R.

    A method of initiating a rapid pH change in a solution comprises irradiating the solution with an intense flux of electromagnetic radiation of a frequency which produces a substantial pK change to a compound in solution. To optimize the resulting pH change, the compound being irradiated in solution should have an excited state lifetime substantially longer than the time required to establish an excited state acid-base equilibrium in the solution. Desired pH changes can be accomplished in nanoseconds or less by means of picosecond pulses of laser radiation.

  18. Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems

    USGS Publications Warehouse

    Vogelmann, James E.; Xian, George; Homer, Collin G.; Tolk, Brian

    2012-01-01

    The focus of the study was to assess gradual changes occurring throughout a range of natural ecosystems using decadal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM +) time series data. Time series data stacks were generated for four study areas: (1) a four scene area dominated by forest and rangeland ecosystems in the southwestern United States, (2) a sagebrush-dominated rangeland in Wyoming, (3) woodland adjacent to prairie in northwestern Nebraska, and (4) a forested area in the White Mountains of New Hampshire. Through analyses of time series data, we found evidence of gradual systematic change in many of the natural vegetation communities in all four areas. Many of the conifer forests in the southwestern US are showing declines related to insects and drought, but very few are showing evidence of improving conditions or increased greenness. Sagebrush communities are showing decreases in greenness related to fire, mining, and probably drought, but very few of these communities are showing evidence of increased greenness or improving conditions. In Nebraska, forest communities are showing local expansion and increased canopy densification in the prairie–woodland interface, and in the White Mountains high elevation understory conifers are showing range increases towards lower elevations. The trends detected are not obvious through casual inspection of the Landsat images. Analyses of time series data using many scenes and covering multiple years are required in order to develop better impressions and representations of the changing ecosystem patterns and trends that are occurring. The approach described in this paper demonstrates that Landsat time series data can be used operationally for assessing gradual ecosystem change across large areas. Local knowledge and available ancillary data are required in order to fully understand the nature of these trends.

  19. Abrupt climate-triggered lake ecosystem changes recorded in late glacial lake sediments in northern Poland

    NASA Astrophysics Data System (ADS)

    Slowinski, M. M.; Zawiska, I.; Ott, F.; Noryskiewicz, A. M.; Apolinarska, K.; Lutynska, M.; Michczynska, D. J.; Brauer, A.; Wulf, S.; Skubala, P.; Blaszkiewicz, M.

    2013-12-01

    The aim of this study was to better understand how local lake ecosystems responded to abrupt climate changes through applying multi-proxy sediment analyses. Therefore, we carried out a detailed and high-resolution case study on the late glacial sediment from the Trzechowskie palaeolake located in the eastern part of the Pomeranian Lakeland, northern Poland. We reconstructed climate induced environmental changes in the paleolake and its catchment using biotic proxies (macrofossils, pollen, cladocera, diatoms, oribatidae mite) and classical geochemical proxies (δ18O, δ13C, loss-on-ignition, CaCO3 content) in combination with high-resolution μ-XRF element core scanning. The core chronology has been established by means of biostratigraphy, AMS 14C-dating on plant macro remains, varve counting in laminated intervals and tephrochronology. The latter was possible by the discovery of the late Allerød Laacher See Tephra for the first time at such eastern location. Biogenic accumulation in the lake started rather late during the lateglacial interstadial at 13903×170 cal yrs BP. The rapid and pronounced cooling at the beginning of the Younger Dryas had a major impact on the lake and its catchment as clearly reflected by both, biotic and geochemical proxies. The depositional environment of the lake abruptly changed from a varved to massive gytjia. The pronounced warming at the demise of Younger Dryas cooling is well-reflected in all environmental indicators but with conspicuous leads and lags reflecting complex responses of lake ecosystems to climate warming. The research was supported by the National Science Centre Poland - NN306085037. This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association.

  20. Changing landowners, changing ecosystem? Land-ownership motivations as drivers of land management practices.

    PubMed

    Sorice, Michael G; Kreuter, Urs P; Wilcox, Bradford P; Fox, William E

    2014-01-15

    Motivations for owning rural land are shifting from an agricultural-production orientation to a preference for natural and cultural amenities. Resultant changes in land management have significant implications for the type and distribution of landscape-level disturbances that affect the delivery of ecosystem services. We examined the relationship between motivations for owning land and the implementation of conservation land management practices by landowners in the Southern Great Plains of the United States. Using a mail survey, we classified landowners into three groups: agricultural production, multiple-objective, and lifestyle-oriented. Cross tabulations of landowner group with past, current, and future use of 12 different land management practices (related to prescribed grazing, vegetation management, restoration, and water management) found that lifestyle-oriented landowners were overall less likely to adopt these practices. To the degree that the cultural landscape of rural lands transitions from production-oriented to lifestyle-oriented landowners, the ecological landscape and the associated flow of ecosystem services will likely change. This poses new challenges to natural resource managers regarding education, outreach, and policy; however, a better understanding about the net ecological consequences of lower rates of adoption of conservation management practices requires consideration of the ecological tradeoffs associated with the changing resource dependency of rural landowners. PMID:24374464

  1. A multi-model analysis of risk of ecosystem shifts under climate change

    NASA Astrophysics Data System (ADS)

    Warszawski, Lila; Friend, Andrew; Ostberg, Sebastian; Frieler, Katja; Lucht, Wolfgang; Schaphoff, Sibyll; Beerling, David; Cadule, Patricia; Ciais, Philippe; Clark, Douglas B.; Kahana, Ron; Ito, Akihiko; Keribin, Rozenn; Kleidon, Axel; Lomas, Mark; Nishina, Kazuya; Pavlick, Ryan; Tito Rademacher, Tim; Buechner, Matthias; Piontek, Franziska; Schewe, Jacob; Serdeczny, Olivia; Schellnhuber, Hans Joachim

    2013-12-01

    Climate change may pose a high risk of change to Earth’s ecosystems: shifting climatic boundaries may induce changes in the biogeochemical functioning and structures of ecosystems that render it difficult for endemic plant and animal species to survive in their current habitats. Here we aggregate changes in the biogeochemical ecosystem state as a proxy for the risk of these shifts at different levels of global warming. Estimates are based on simulations from seven global vegetation models (GVMs) driven by future climate scenarios, allowing for a quantification of the related uncertainties. 5-19% of the naturally vegetated land surface is projected to be at risk of severe ecosystem change at 2 ° C of global warming (ΔGMT) above 1980-2010 levels. However, there is limited agreement across the models about which geographical regions face the highest risk of change. The extent of regions at risk of severe ecosystem change is projected to rise with ΔGMT, approximately doubling between ΔGMT = 2 and 3 ° C, and reaching a median value of 35% of the naturally vegetated land surface for ΔGMT = 4 °C. The regions projected to face the highest risk of severe ecosystem changes above ΔGMT = 4 °C or earlier include the tundra and shrublands of the Tibetan Plateau, grasslands of eastern India, the boreal forests of northern Canada and Russia, the savanna region in the Horn of Africa, and the Amazon rainforest.

  2. Managing for Climate Change in Western Forest Ecosystems; The Role of Refugia in Adaptation Strategies (Invited)

    NASA Astrophysics Data System (ADS)

    Millar, C. I.; Morelli, T.

    2009-12-01

    Managing forested ecosystems in western North America for adaptation to climate change involves options that depend on resource objectives, landscape conditions, sensitivity to change, and social desires. Strategies range from preserving species and ecosystems in the face of change (resisting change); managing for resilience to change; realigning ecosystems that have been severely altered so that they can adapt successfully; and enabling species to respond to climate changes. We are exploring one extreme in this range of strategies, that is, to manage locations, species, communities, or ecosystems as refugia. This concept is familiar from the Quaternary literature as isolated locations where climates remained warm during cold glacial intervals and wherein species contracted and persisted in small populations. References to refugia have been made in the climate-adaptation literature but little elaborated, and applications have not been described. We are addressing this gap conceptually and in case-studies from national forest and national park environments in California. Using a classification of refugium categories, we extend the concept beyond the original use to include diverse locations and conditions where plant or animal species, or ecosystems of concern, would persist during future changing climatic backgrounds. These locations may be determined as refugial for reasons of local microclimate, substrate, elevation, topographic context, paleohistory, species ecology, or management capacity. Recognizing that species and ecosystems respond to climate change differently, refugium strategies are appropriate in some situations and not others. We describe favorable conditions for using refugium strategies and elaborate specific approaches in Sierra Nevada case studies.

  3. Terrestrial ecosystems in a changing environment: a dominant role for water.

    PubMed

    Bernacchi, Carl J; VanLoocke, Andy

    2015-01-01

    Transpiration--the movement of water from the soil, through plants, and into the atmosphere--is the dominant water flux from the earth's terrestrial surface. The evolution of vascular plants, while increasing terrestrial primary productivity, led to higher transpiration rates and widespread alterations in the global climate system. Similarly, anthropogenic influences on transpiration rates are already influencing terrestrial hydrologic cycles, with an even greater potential for changes lying ahead. Intricate linkages among anthropogenic activities, terrestrial productivity, the hydrologic cycle, and global demand for ecosystem services will lead to increased pressures on ecosystem water demands. Here, we focus on identifying the key drivers of ecosystem water use as they relate to plant physiological function, the role of predicted global changes in ecosystem water uses, trade-offs between ecosystem water use and carbon uptake, and knowledge gaps. PMID:25621516

  4. Bridging the Divide: Linking Genomics to Ecosystem Responses to Climate Change: Final Report

    SciTech Connect

    Smith, Melinda D.

    2014-03-15

    Over the project period, we have addressed the following objectives: 1) assess the effects of altered precipitation patterns (i.e., increased variability in growing season precipitation) on genetic diversity of the dominant C4 grass species, Andropogon gerardii, and 2) experimentally assess the impacts of extreme climatic events (heat wave, drought) on responses of the dominant C4 grasses, A. gerardii and Sorghastrum nutans, and the consequences of these response for community and ecosystem structure and function. Below is a summary of how we have addressed these objectives. Objective 1 After ten years of altered precipitation, we found the number of genotypes of A. gerardii was significantly reduced compared to the ambient precipitation treatments (Avolio et al., 2013a). Although genotype number was reduced, the remaining genotypes were less related to one another indicating that the altered precipitation treatment was selecting for increasingly dissimilar genomes (based on mean pairwise Dice distance among individuals). For the four key genotypes that displayed differential abundances depending on the precipitation treatment (G1, G4, and G11 in the altered plots and G2 in the ambient plots), we identified phenotypic differences in the field that could account for ecological sorting (Avolio & Smith, 2013a). The three altered rainfall genotypes also have very different phenotypic traits in the greenhouse in response to different soil moisture availabilities (Avolio and Smith, 2013c). Two of the genotypes that increased in abundance in the altered precipitation plots had greater allocation to root biomass (G4 and G11), while G1 allocated more biomass aboveground. These phenotypic differences among genotypes suggests that changes in genotypic structure between the altered and the ambient treatments has likely occurred via niche differentiation, driven by changes in soil moisture dynamics (reduced mean, increased variability and changes in the depth distribution of

  5. 76 FR 55060 - Aquatic Ecosystems, Water Quality, and Global Change: Challenges of Conducting Multi-Stressor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... resilience of ecosystems and human systems to a variety of existing stresses and mal- adaptations. DATES: The... a result of existing global change stresses and mal-adaptations. The work described in this...

  6. Social-Ecological Controls Over Earth-System Stewardship: a Framework for Sustainability in a Rapidly Changing World

    NASA Astrophysics Data System (ADS)

    Chapin, F. S.; Power, M. E.; Pickett, S.; Jackson, R. B.; Carter, D.; Harden, J. W.

    2010-12-01

    Human actions are having large and accelerating effects on Earth’s climate, environment, and ecosystems, thereby degrading ecosystem services required by society. This unsustainable trajectory demands a dramatic change in the relationship of humans with the environment and life-support systems of the planet. Earth-system stewardship is an action-oriented framework intended to foster social-ecological sustainability of a rapidly changing world. This builds on problem-relevant research about the social-ecological interactions that drive earth-system change. These include spiraling consumption in developed nations and the broadening gap between the livelihoods of rich and poor people within and among countries. Science that contributes effectively to reversing these trends requires an ongoing dialogue between scientists and users at multiple scales, communicated with sensitivity to social and cultural norms. Such science must motivate behavioral change and deliver information that is perceived as objective, timely, and useful to problem-solving. Recent developments identify four strategies that use current understanding in an environment of inevitable uncertainty and abrupt change: (1) reducing the magnitude of, and exposure and sensitivity to, known stresses; (2) focusing on proactive policies that shape change; and (3) avoiding or escaping unsustainable social-ecological traps. All social-ecological systems are vulnerable to change but have sources of adaptive capacity and resilience that can sustain ecosystem services and human well-being. Discovering and nurturing these sources of adaptive capacity requires, and defines active ecosystem stewardship.

  7. The Changing Nature of Transitions in the Evolution of a Floodplain Wetland Ecosystem

    NASA Astrophysics Data System (ADS)

    Thoms, M. C.

    2015-12-01

    Flood plain ecosystems are mosaics of physical units and the sediments contained within these often display a high degree of spatial and temporal complexity. This paper reconstructs the environmental history of a large floodplain ecosystem in North-west New South Wales. Sediment cores, up to 14 m in depth, extracted from the Narran floodplain ecosystem have undergone detailed stratigraphic, geochemical and textural analyses. When combined with a series of dates obtained from various depths in the cores a complex environmental history is revealed. The Narran floodplain ecosystem is between 40,000 to 85,000 years old that has undergone three major changes in state. From a relatively simple initial state, divergent evolution processes resulted in an ecosystem that experienced periodic and major changes in water and sediment inputs. Finally, a change in flow and sediment regimes approximately 25,000 years ago resulted in the formation of the current floodplain ecosystem. Three major thresholds have thus been recorded, the character of which differs markedly. This study highlights how various numerical methods, in association with standard sedimentological techniques, can assist in unravelling the environmental complexity, identification of thresholds, their character as well as the divergent and convergent trajectories of change in floodplain ecosystems.

  8. Climate Change and Ecosystem Services Output Efficiency in Southern Loblolly Pine Forests.

    PubMed

    Susaeta, Andres; Adams, Damian C; Carter, Douglas R; Dwivedi, Puneet

    2016-09-01

    Forests provide myriad ecosystem services that are vital to humanity. With climate change, we expect to see significant changes to forests that will alter the supply of these critical services and affect human well-being. To better understand the impacts of climate change on forest-based ecosystem services, we applied a data envelopment analysis method to assess plot-level efficiency in the provision of ecosystem services in Florida natural loblolly pine (Pinus taeda L.) forests. Using field data for n = 16 loblolly pine forest plots, including inputs such as site index, tree density, age, precipitation, and temperatures for each forest plot, we assessed the relative plot-level production of three ecosystem services: timber, carbon sequestered, and species richness. The results suggested that loblolly pine forests in Florida were largely inefficient in the provision of these ecosystem services under current climatic conditions. Climate change had a small negative impact on the loblolly pine forests efficiency in the provision of ecosystem services. In this context, we discussed the reduction of tree density that may not improve ecosystem services production. PMID:27263100

  9. Climate Change and Ecosystem Services Output Efficiency in Southern Loblolly Pine Forests

    NASA Astrophysics Data System (ADS)

    Susaeta, Andres; Adams, Damian C.; Carter, Douglas R.; Dwivedi, Puneet

    2016-09-01

    Forests provide myriad ecosystem services that are vital to humanity. With climate change, we expect to see significant changes to forests that will alter the supply of these critical services and affect human well-being. To better understand the impacts of climate change on forest-based ecosystem services, we applied a data envelopment analysis method to assess plot-level efficiency in the provision of ecosystem services in Florida natural loblolly pine ( Pinus taeda L.) forests. Using field data for n = 16 loblolly pine forest plots, including inputs such as site index, tree density, age, precipitation, and temperatures for each forest plot, we assessed the relative plot-level production of three ecosystem services: timber, carbon sequestered, and species richness. The results suggested that loblolly pine forests in Florida were largely inefficient in the provision of these ecosystem services under current climatic conditions. Climate change had a small negative impact on the loblolly pine forests efficiency in the provision of ecosystem services. In this context, we discussed the reduction of tree density that may not improve ecosystem services production.

  10. Changing Arctic ecosystems--the role of ecosystem changes across the Boreal-Arctic transition zone on the distribution and abundance of wildlife populations

    USGS Publications Warehouse

    McNew, Lance; Handel, Colleen; Pearce, John; DeGange, Anthony R.; Holland-Bartels, Leslie; Whalen, Mary

    2013-01-01

    Arctic and boreal ecosystems provide important breeding habitat for more than half of North America’s migratory birds as well as many resident species. Northern landscapes are projected to experience more pronounced climate-related changes in habitat than most other regions. These changes include increases in shrub growth, conversion of tundra to forest, alteration of wetlands, shifts in species’ composition, and changes in the frequency and scale of fires and insect outbreaks. Changing habitat conditions, in turn, may have significant effects on the distribution and abundance of wildlife in these critical northern ecosystems. The U.S. Geological Survey (USGS) is conducting studies in the Boreal–Arctic transition zone of Alaska, an environment of accelerated change in this sensitive margin between Arctic tundra and boreal forest.

  11. Uncovering the volatile nature of tropical coastal marine ecosystems in a changing world.

    PubMed

    Exton, Dan A; McGenity, Terry J; Steinke, Michael; Smith, David J; Suggett, David J

    2015-04-01

    Biogenic volatile organic compounds (BVOCs), in particular dimethyl sulphide (DMS) and isoprene, have fundamental ecological, physiological and climatic roles. Our current understanding of these roles is almost exclusively established from terrestrial or oceanic environments but signifies a potentially major, but largely unknown, role for BVOCs in tropical coastal marine ecosystems. The tropical coast is a transition zone between the land and ocean, characterized by highly productive and biodiverse coral reefs, seagrass beds and mangroves, which house primary producers that are amongst the greatest emitters of BVOCs on the planet. Here, we synthesize our existing understanding of BVOC emissions to produce a novel conceptual framework of the tropical marine coast as a continuum from DMS-dominated reef producers to isoprene-dominated mangroves. We use existing and previously unpublished data to consider how current environmental conditions shape BVOC production across the tropical coastal continuum, and in turn how BVOCs can regulate environmental stress tolerance or species interactions via infochemical networks. We use this as a framework to discuss how existing predictions of future tropical coastal BVOC emissions, and the roles they play, are effectively restricted to present day 'baseline' trends of BVOC production across species and environmental conditions; as such, there remains a critical need to focus research efforts on BVOC responses to rapidly accelerating anthropogenic impacts at local and regional scales. We highlight the complete lack of current knowledge required to understand the future ecological functioning of these important systems, and to predict whether feedback mechanisms are likely to regulate or exacerbate current climate change scenarios through environmentally and ecologically mediated changes to BVOC budgets at the ecosystem level. PMID:25311223

  12. Climatic Change and Marine Ecosystems in the NE Pacific: A Holocene Perspective

    NASA Astrophysics Data System (ADS)

    Finney, B. P.; Addison, J. A.

    2006-12-01

    Historical records suggest strong responses of marine ecosystems to climatic change in the NE Pacific Ocean. The abundance of zooplankton, salmon and other marine organisms varied substantially during the 20th century, and appear to correlate with inter-decadal climate variability. To better understand marine ecosystem-climate linkages, proxy records from a variety of sources are being assembled and compared. Paleoceanographic changes are being reconstructed from sediment cores from the fjords and continental margin of the Gulf of Alaska, where the rapidly accumulating sediment can resolve environmental changes on annual to decadal timescales. Past sockeye salmon abundance is reconstructed by analyzing nitrogen stable isotopes in sediment cores from lakes where sockeye return to spawn. Paleoclimatic data is available for this region from studies of tree rings, lake sediments, ice cores and glacial advances. The changes in primary and secondary ocean production in this region indicate that climatic forcing has direct impacts on lower trophic levels, which subsequently affects salmon production probably through food availability a hypothesis that can be assessed through paleoenvironmental analyses. Preliminary multi-proxy data on ocean paleoproductivity indicates substantial variability during the Holocene over a range of timescales. Productivity appears to have generally increased during the Holocene, with relatively higher levels during the little ice age, and in the last few decades. Reconstructions of salmon abundance from a suite of lakes show generally similar patterns, consistent with the hypothesis that climate is an important driver of their abundance. Over the Holocene, shifts in salmon abundance far exceed the historical decadal-scale variability. Salmon abundance generally increased over the Holocene, punctuated by several abrupt steps, as well as multi-decadal variability. Salmon increased during neoglaciation (c.a. 3500 yr BP), and were consistently

  13. Reserve Design under Climate Change: From Land Facets Back to Ecosystem Representation

    PubMed Central

    Schneider, Richard R.; Bayne, Erin M.

    2015-01-01

    Ecosystem distributions are expected to shift as a result of global warming, raising concerns about the long-term utility of reserve systems based on coarse-filter ecosystem representation. We tested the extent to which proportional ecosystem representation targets would be maintained under a changing climate by projecting the distribution of the major ecosystems of Alberta, Canada, into the future using bioclimatic envelope models and then calculating the composition of reserves in successive periods. We used the Marxan conservation planning software to generate the suite of reserve systems for our test, varying the representation target and degree of reserve clumping. Our climate envelope projections for the 2080s indicate that virtually all reserves will, in time, be comprised of different ecosystem types than today. Nevertheless, our proportional targets for ecosystem representation were maintained across all time periods, with only minor exceptions. We hypothesize that this stability in representation arises because ecosystems may be serving as proxies for land facets, the stable abiotic landscape features that delineate major arenas of biological activity. The implication is that accommodating climate change may not require abandoning the conventional ecosystem-based approach to reserve design in favour of a strictly abiotic approach, since the two approaches may be largely synonymous. PMID:25978759

  14. Unexpected patterns of vegetation distribution response and climate change velocities in cold ecosystems

    NASA Astrophysics Data System (ADS)

    Macias-Fauria, M.; Johnson, E. A.; Forbes, B. C.; Willis, K. J.

    2013-12-01

    climate warming in the region (Macias-Fauria & Johnson 20013, PNAS). 2) In the low arctic tundra, un-treed to treed landscapes have sprouted in several parts of the tundra in a matter of decades, as opposed to the previously predicted response times of several centuries for boreal forest to advance to its new climate optimum (migrational lags). This takes place not through very rapid moving fronts, but through phenotypic responses of extant vegetation with highly flexible life forms, such as woody deciduous shrubs (Salix, Alnus, Betula). The resulting vegetation response creates strong energy feedbacks while at the same time potentially further reduces the speed of northward displacement of the boreal forest, that has to compete with a new treed ecosystem (Macias-Fauria et al. 2012, Nature Climate Change). In conclusion, control of rates of migration by factors other than climate in mountain systems can largely reduce the ability of vegetation to track climate change, and emergence of structurally novel ecosystems in low arctic tundra might largely alter current predictions based on climate response of vegetation, by accelerating ecosystem change and reducing migrational rates simultaneously.

  15. The more things change, the more they stay the same? When is trait variability important for stability of ecosystem function in a changing environment.

    PubMed

    Wright, Justin P; Ames, Gregory M; Mitchell, Rachel M

    2016-05-19

    The importance of intraspecific trait variability for community dynamics and ecosystem functioning has been underappreciated. There are theoretical reasons for predicting that species that differ in intraspecific trait variability will also differ in their effects on ecosystem functioning, particularly in variable environments. We discuss whether species with greater trait variability are likely to exhibit greater temporal stability in their population dynamics, and under which conditions this might lead to stability in ecosystem functioning. Resolving this requires us to consider several questions. First, are species with high levels of variation for one trait equally variable in others? In particular, is variability in response and effects traits typically correlated? Second, what is the relative contribution of local adaptation and phenotypic plasticity to trait variability? If local adaptation dominates, then stability in function requires one of two conditions: (i) individuals of appropriate phenotypes present in the environment at high enough frequencies to allow for populations to respond rapidly to the changing environment, and (ii) high levels of dispersal and gene flow. While we currently lack sufficient information on the causes and distribution of variability in functional traits, filling in these key data gaps should increase our ability to predict how changing biodiversity will alter ecosystem functioning. PMID:27114574

  16. Response of plants and ecosystems to CO{sub 2} and climate change. Final technical report

    SciTech Connect

    Reynolds, J.F.

    1993-12-31

    In recognition of the important role of vegetation in the bio-geosphere carbon cycle, the Carbon Dioxide Research Program of the US Department of Energy established the research program: Direct Effects of increasing Carbon Dioxide on Vegetation. The ultimate goal is to develop a general ecosystem model to investigate, via hypothesis testing, the potential responses of different terrestrial ecosystems to changes in the global environment over the next century. The approach involves the parallel development of models at several hierarchical levels, from the leaf to the ecosystem. At the plant level, mechanism and the direct effects of CO{sub 2} in the development of a general plant growth model, GEPSI - GEneral Plant SImulator has been stressed. At the ecosystem level, we have stressed the translation Of CO{sub 2} effects and other aspects of climate change throughout the ecosystem, including feedbacks and constraints to system response, in the development of a mechanistic, general ecosystem model SERECO - Simulation of Ecosystem Response to Elevated CO{sub 2} and Climate Change has been stressed.

  17. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate.

    PubMed

    Duan, Kai; Sun, Ge; Sun, Shanlei; Caldwell, Peter V; Cohen, Erika C; McNulty, Steven G; Aldridge, Heather D; Zhang, Yang

    2016-01-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m(-2) yr(-1) (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr(-1) (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr(-1)). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services. PMID:27100360

  18. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate

    PubMed Central

    Duan, Kai; Sun, Ge; Sun, Shanlei; Caldwell, Peter V.; Cohen, Erika C.; McNulty, Steven G.; Aldridge, Heather D.; Zhang, Yang

    2016-01-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m−2 yr−1 (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr−1 (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr−1). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services. PMID:27100360

  19. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate

    NASA Astrophysics Data System (ADS)

    Duan, Kai; Sun, Ge; Sun, Shanlei; Caldwell, Peter V.; Cohen, Erika C.; McNulty, Steven G.; Aldridge, Heather D.; Zhang, Yang

    2016-04-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m‑2 yr‑1 (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr‑1 (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr‑1). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services.

  20. Evaluating ecosystem service change in Jiangxi Province of China based on Landsat imagery

    NASA Astrophysics Data System (ADS)

    Zhong, Taiyang; Huang, Xianjing; Ma, Yuandan

    2009-10-01

    The function and services of ecosystem are important components of the life-support system in the planet, as well as the basic elements for sustainable development of environment and society. In this study, the change of ecosystem function and services in Jiangxi Province of China were estimated by employing the classification and economic parameters from Costanza et al. The types and area of terrestrial ecosystems in 1980s and 2000s were identified from Landsat imagery, based on the maximum likelihood classification methods. And then the distribution maps of ecosystem services of Jiangxi Province were drawn. The value for terrestrial ecosystem was 2522x108 RMB in 1980s, while it increased by 7.3% in 2000s, which mainly because the increased forest areas in Jiangxi Province. The estimation method employed in this study was conservative, and should be improved in future studies.

  1. Biomass is the main driver of changes in ecosystem process rates during tropical forest succession.

    PubMed

    Lohbeck, Madelon; Poorter, Lourens; Martínez-Ramos, Miguel; Bongers, Frans

    2015-05-01

    Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity, actual litter decomposition, and potential litter decomposition) during secondary succession after shifting cultivation in wet tropical forest of Mexico. We test the importance of three alternative drivers of ecosystem processes: vegetation biomass (vegetation quantity hypothesis), community-weighted trait mean (mass ratio hypothesis), and functional diversity (niche complementarity hypothesis) using structural equation modeling. This allows us to infer the relative importance of different mechanisms underlying ecosystem process recovery. Ecosystem process rates changed during succession, and the strongest driver was aboveground biomass for each of the processes. Productivity of aboveground stem biomass and leaf litter as well as actual litter decomposition increased with initial standing vegetation biomass, whereas potential litter decomposition decreased with standing biomass. Additionally, biomass productivity was positively affected by community-weighted mean of specific leaf area, and potential decomposition was positively affected by functional divergence, and negatively by community-weighted mean of leaf dry matter content. Our empirical results show that functional diversity and community-weighted means are of secondary importance for explaining changes in ecosystem process rates during tropical forest succession. Instead, simply, the amount of vegetation in a site is the major driver of changes, perhaps because there is a steep biomass buildup during succession that overrides more subtle effects of community functional properties on ecosystem processes. We recommend future studies in the field of biodiversity and ecosystem functioning to separate the effects of

  2. Drought-induced changes in flow regimes lead to long-term losses in mussel-provided ecosystem services

    PubMed Central

    Vaughn, Caryn C; Atkinson, Carla L; Julian, Jason P

    2015-01-01

    Extreme hydro-meteorological events such as droughts are becoming more frequent, intense, and persistent. This is particularly true in the south central USA, where rapidly growing urban areas are running out of water and human-engineered water storage and management are leading to broad-scale changes in flow regimes. The Kiamichi River in southeastern Oklahoma, USA, has high fish and freshwater mussel biodiversity. However, water from this rural river is desired by multiple urban areas and other entities. Freshwater mussels are large, long-lived filter feeders that provide important ecosystem services. We ask how observed changes in mussel biomass and community composition resulting from drought-induced changes in flow regimes might lead to changes in river ecosystem services. We sampled mussel communities in this river over a 20-year period that included two severe droughts. We then used laboratory-derived physiological rates and river-wide estimates of species-specific mussel biomass to estimate three aggregate ecosystem services provided by mussels over this time period: biofiltration, nutrient recycling (nitrogen and phosphorus), and nutrient storage (nitrogen, phosphorus, and carbon). Mussel populations declined over 60%, and declines were directly linked to drought-induced changes in flow regimes. All ecosystem services declined over time and mirrored biomass losses. Mussel declines were exacerbated by human water management, which has increased the magnitude and frequency of hydrologic drought in downstream reaches of the river. Freshwater mussels are globally imperiled and declining around the world. Summed across multiple streams and rivers, mussel losses similar to those we document here could have considerable consequences for downstream water quality although lost biofiltration and nutrient retention. While we cannot control the frequency and severity of climatological droughts, water releases from reservoirs could be used to augment stream flows and

  3. Drought-induced changes in flow regimes lead to long-term losses in mussel-provided ecosystem services.

    PubMed

    Vaughn, Caryn C; Atkinson, Carla L; Julian, Jason P

    2015-03-01

    Extreme hydro-meteorological events such as droughts are becoming more frequent, intense, and persistent. This is particularly true in the south central USA, where rapidly growing urban areas are running out of water and human-engineered water storage and management are leading to broad-scale changes in flow regimes. The Kiamichi River in southeastern Oklahoma, USA, has high fish and freshwater mussel biodiversity. However, water from this rural river is desired by multiple urban areas and other entities. Freshwater mussels are large, long-lived filter feeders that provide important ecosystem services. We ask how observed changes in mussel biomass and community composition resulting from drought-induced changes in flow regimes might lead to changes in river ecosystem services. We sampled mussel communities in this river over a 20-year period that included two severe droughts. We then used laboratory-derived physiological rates and river-wide estimates of species-specific mussel biomass to estimate three aggregate ecosystem services provided by mussels over this time period: biofiltration, nutrient recycling (nitrogen and phosphorus), and nutrient storage (nitrogen, phosphorus, and carbon). Mussel populations declined over 60%, and declines were directly linked to drought-induced changes in flow regimes. All ecosystem services declined over time and mirrored biomass losses. Mussel declines were exacerbated by human water management, which has increased the magnitude and frequency of hydrologic drought in downstream reaches of the river. Freshwater mussels are globally imperiled and declining around the world. Summed across multiple streams and rivers, mussel losses similar to those we document here could have considerable consequences for downstream water quality although lost biofiltration and nutrient retention. While we cannot control the frequency and severity of climatological droughts, water releases from reservoirs could be used to augment stream flows and

  4. Rapid environmental degradation in a subarctic ecosystem influences resource use of a keystone avian herbivore.

    PubMed

    Winiarski, Kristopher J; McWilliams, Scott R; Rockwell, Robert F

    2012-09-01

    1. Environmental degradation can change resource use strategies of animals and thereby affect survival and fitness. Arctic herbivores may be especially susceptible to the effects of such environmental change because their rapid growth rates demand high-quality forage, which may be limited as environmental conditions deteriorate. We studied the consequences of a trophic cascade, driven by Lesser Snow Goose (Chen caerulescens caerulescens) overgrazing on the south-west coast of Hudson Bay, Canada, which has caused tidal marsh (TM) degradation and the reduction in high-quality forage plants, on gosling growth and resource use. 2. We compared resource use and body size of goslings that inhabited tidal and freshwater marsh (FM) to determine how current foraging strategies influence growth and to test the hypothesis that during early growth goslings require and so consume high-quality TM plants, but that during later growth they may switch to foraging in lower-quality FM. 3. To investigate gosling resource use throughout growth, we measured once a week for 28 days the body size of goslings as well as stable isotope ratios (δ(34) S, δ(15) N and δ(13) C) in multiple tissues of goslings that were collected from both TM and nearby FM. We also measured the stable isotope ratios in forage plants sampled along transects and from gosling foreguts. We used an isotope-mixing model to determine the contribution of FM plants to gosling tissues. 4. Contrary to the proposed hypothesis, goslings inhabiting FM or TM primarily consumed FM plants during early growth. Furthermore, goslings that foraged extensively in FM had similar growth rates and grew to a similar size and body mass, as goslings that foraged in the degraded TM. However, goslings that currently inhabit freshwater or TM were significantly smaller than goslings that inhabited TM in the 1980s prior to habitat degradation. 5. Consequences of smaller overall body size include decreased survival and fecundity for arctic

  5. The Chinese Experience of Rapid Modernization: Sociocultural Changes, Psychological Consequences?

    PubMed Central

    Sun, Jiahong; Ryder, Andrew G.

    2016-01-01

    Mainland China has undergone profound changes dating back to the nineteenth century, including a contemporary period of rapid modernization that began in the 1980s. The result has been dramatic social, cultural, and economic shifts impacting the daily lives of Chinese people. In this paper, we explore the psychological implications of sociocultural transformation in China, emphasizing two central themes. First, rising individualism: findings from social and developmental psychology suggest that China’s rapid development has been accompanied by ever-increasing adherence to individualistic values. Second, rising rates of depression: findings from psychiatric epidemiology point to increasing prevalence of depression over this same time period, particularly in rural settings. We argue that links between sociocultural and psychological shifts in China can be usefully studied through a cultural psychology lens, emphasizing the mutual constitution of culture, mind, and brain. In particular, we note that the link between social change, individualism, and rising mental illness deserves careful attention. Our review suggests that shifting values and socialization practices shape emotion norms of concealment and display, with implications for depressive symptom presentation. The challenge comes with interpretation. Increasing prevalence rates of depression may indeed be a general response to the rapidity of sociocultural change, or a specific consequence of rising individualism—but may also result from increasingly ‘Western’ patterns of symptom presentation, or improvements in diagnostic practice. We conclude by considering the challenges posed to standard universal models of psychological phenomena. PMID:27092093

  6. The Chinese Experience of Rapid Modernization: Sociocultural Changes, Psychological Consequences?

    PubMed

    Sun, Jiahong; Ryder, Andrew G

    2016-01-01

    Mainland China has undergone profound changes dating back to the nineteenth century, including a contemporary period of rapid modernization that began in the 1980s. The result has been dramatic social, cultural, and economic shifts impacting the daily lives of Chinese people. In this paper, we explore the psychological implications of sociocultural transformation in China, emphasizing two central themes. First, rising individualism: findings from social and developmental psychology suggest that China's rapid development has been accompanied by ever-increasing adherence to individualistic values. Second, rising rates of depression: findings from psychiatric epidemiology point to increasing prevalence of depression over this same time period, particularly in rural settings. We argue that links between sociocultural and psychological shifts in China can be usefully studied through a cultural psychology lens, emphasizing the mutual constitution of culture, mind, and brain. In particular, we note that the link between social change, individualism, and rising mental illness deserves careful attention. Our review suggests that shifting values and socialization practices shape emotion norms of concealment and display, with implications for depressive symptom presentation. The challenge comes with interpretation. Increasing prevalence rates of depression may indeed be a general response to the rapidity of sociocultural change, or a specific consequence of rising individualism-but may also result from increasingly 'Western' patterns of symptom presentation, or improvements in diagnostic practice. We conclude by considering the challenges posed to standard universal models of psychological phenomena. PMID:27092093

  7. Rapid changes in the gut microbiome during human evolution.

    PubMed

    Moeller, Andrew H; Li, Yingying; Mpoudi Ngole, Eitel; Ahuka-Mundeke, Steve; Lonsdorf, Elizabeth V; Pusey, Anne E; Peeters, Martine; Hahn, Beatrice H; Ochman, Howard

    2014-11-18

    Humans are ecosystems containing trillions of microorganisms, but the evolutionary history of this microbiome is obscured by a lack of knowledge about microbiomes of African apes. We sequenced the gut communities of hundreds of chimpanzees, bonobos, and gorillas and developed a phylogenetic approach to reconstruct how present-day human microbiomes have diverged from those of ancestral populations. Compositional change in the microbiome was slow and clock-like during African ape diversification, but human microbiomes have deviated from the ancestral state at an accelerated rate. Relative to the microbiomes of wild apes, human microbiomes have lost ancestral microbial diversity while becoming specialized for animal-based diets. Individual wild apes cultivate more phyla, classes, orders, families, genera, and species of bacteria than do individual humans across a range of societies. These results indicate that humanity has experienced a depletion of the gut flora since diverging from Pan. PMID:25368157

  8. Rapid changes in the gut microbiome during human evolution

    PubMed Central

    Moeller, Andrew H.; Li, Yingying; Mpoudi Ngole, Eitel; Ahuka-Mundeke, Steve; Lonsdorf, Elizabeth V.; Pusey, Anne E.; Peeters, Martine; Hahn, Beatrice H.; Ochman, Howard

    2014-01-01

    Humans are ecosystems containing trillions of microorganisms, but the evolutionary history of this microbiome is obscured by a lack of knowledge about microbiomes of African apes. We sequenced the gut communities of hundreds of chimpanzees, bonobos, and gorillas and developed a phylogenetic approach to reconstruct how present-day human microbiomes have diverged from those of ancestral populations. Compositional change in the microbiome was slow and clock-like during African ape diversification, but human microbiomes have deviated from the ancestral state at an accelerated rate. Relative to the microbiomes of wild apes, human microbiomes have lost ancestral microbial diversity while becoming specialized for animal-based diets. Individual wild apes cultivate more phyla, classes, orders, families, genera, and species of bacteria than do individual humans across a range of societies. These results indicate that humanity has experienced a depletion of the gut flora since diverging from Pan. PMID:25368157

  9. Coordinated Approaches to Quantify Long-Term Ecosystem dynamics in Response to Global Change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change and its impact on ecosystems are usually assessed at decadal and century time scales. Ecological responses to climate change at those scales are strongly regulated by long-term processes, such as changes in species composition, carbon dynamics in soil and by big trees, and nutrient r...

  10. Developing priority variables ("ecosystem Essential Ocean Variables" - eEOVs) for observing dynamics and change in Southern Ocean ecosystems

    NASA Astrophysics Data System (ADS)

    Constable, Andrew J.; Costa, Daniel P.; Schofield, Oscar; Newman, Louise; Urban, Edward R.; Fulton, Elizabeth A.; Melbourne-Thomas, Jessica; Ballerini, Tosca; Boyd, Philip W.; Brandt, Angelika; de la Mare, Willaim K.; Edwards, Martin; Eléaume, Marc; Emmerson, Louise; Fennel, Katja; Fielding, Sophie; Griffiths, Huw; Gutt, Julian; Hindell, Mark A.; Hofmann, Eileen E.; Jennings, Simon; La, Hyoung Sul; McCurdy, Andrea; Mitchell, B. Greg; Moltmann, Tim; Muelbert, Monica; Murphy, Eugene; Press, Anthony J.; Raymond, Ben; Reid, Keith; Reiss, Christian; Rice, Jake; Salter, Ian; Smith, David C.; Song, Sun; Southwell, Colin; Swadling, Kerrie M.; Van de Putte, Anton; Willis, Zdenka

    2016-09-01

    Reliable statements about variability and change in marine ecosystems and their underlying causes are needed to report on their status and to guide management. Here we use the Framework on Ocean Observing (FOO) to begin developing ecosystem Essential Ocean Variables (eEOVs) for the Southern Ocean Observing System (SOOS). An eEOV is a defined biological or ecological quantity, which is derived from field observations, and which contributes significantly to assessments of Southern Ocean ecosystems. Here, assessments are concerned with estimating status and trends in ecosystem properties, attribution of trends to causes, and predicting future trajectories. eEOVs should be feasible to collect at appropriate spatial and temporal scales and are useful to the extent that they contribute to direct estimation of trends and/or attribution, and/or development of ecological (statistical or simulation) models to support assessments. In this paper we outline the rationale, including establishing a set of criteria, for selecting eEOVs for the SOOS and develop a list of candidate eEOVs for further evaluation. Other than habitat variables, nine types of eEOVs for Southern Ocean taxa are identified within three classes: state (magnitude, genetic/species, size spectrum), predator-prey (diet, foraging range), and autecology (phenology, reproductive rate, individual growth rate, detritus). Most candidates for the suite of Southern Ocean taxa relate to state or diet. Candidate autecological eEOVs have not been developed other than for marine mammals and birds. We consider some of the spatial and temporal issues that will influence the adoption and use of eEOVs in an observing system in the Southern Ocean, noting that existing operations and platforms potentially provide coverage of the four main sectors of the region - the East and West Pacific, Atlantic and Indian. Lastly, we discuss the importance of simulation modelling in helping with the design of the observing system in the long

  11. Minimizing impacts of land use change on ecosystem services using multi-criteria heuristic analysis.

    PubMed

    Keller, Arturo A; Fournier, Eric; Fox, Jessica

    2015-06-01

    Development of natural landscapes to support human activities impacts the capacity of the landscape to provide ecosystem services. Typically, several ecosystem services are impacted at a single development site and various footprint scenarios are possible, thus a multi-criteria analysis is needed. Restoration potential should also be considered for the area surrounding the permanent impact site. The primary objective of this research was to develop a heuristic approach to analyze multiple criteria (e.g. impacts to various ecosystem services) in a spatial configuration with many potential development sites. The approach was to: (1) quantify the magnitude of terrestrial ecosystem service (biodiversity, carbon sequestration, nutrient and sediment retention, and pollination) impacts associated with a suite of land use change scenarios using the InVEST model; (2) normalize results across categories of ecosystem services to allow cross-service comparison; (3) apply the multi-criteria heuristic algorithm to select sites with the least impact to ecosystem services, including a spatial criterion (separation between sites). As a case study, the multi-criteria impact minimization algorithm was applied to InVEST output to select 25 potential development sites out of 204 possible locations (selected by other criteria) within a 24,000 ha property. This study advanced a generally applicable spatial multi-criteria approach for 1) considering many land use footprint scenarios, 2) balancing impact decisions across a suite of ecosystem services, and 3) determining the restoration potential of ecosystem services after impacts. PMID:25794964

  12. Climate Change Experiments in Arctic Ecosystems: Scientific Strategy and Design Criteria

    NASA Astrophysics Data System (ADS)

    Wullschleger, S. D.; Hinzman, L. D.; McGuire, A. D.; Oberbauer, S. F.; Oechel, W. C.; Norby, R. J.; Thornton, P. E.; Schuur, E. A.; Shugart, H. H.; Walsh, J. E.; Wilson, C. J.

    2010-12-01

    Arctic and subarctic ecosystems are sensitive to changes in climate. These are among the largest and coldest of all ecosystems and are perceived by many as especially vulnerable to environmental change. Warming, in particular, is expected to be greatest in northern latitudes with potentially significant consequences for tundra, taiga, and peat lands. Observational evidence suggests that warming is already affecting physical and ecological processes in high-latitude ecosystems. Models predict that permafrost degradation and the northward expansion of shrubs into tundra represent important feedbacks on climate. Manipulative experiments can help understand the vulnerability of ecosystems to climate warming. Previous attempts to manipulate the environment of ecosystems in arctic and subarctic regions have focused on warming plant and soils, but treatments have been limited to small scales and modest increases in temperature. Manipulating the environment at larger scales and exposing ecosystems to higher temperatures for longer periods of time will be required to fully describe the physical, chemical, and biological mechanisms that govern land-atmosphere interactions. A variety of logistical and engineering challenges must be overcome and new approaches developed before we can address the questions being asked of the scientific community especially as we continue to move toward large-scale and long-term experiments. In light of the many uncertainties that surround the response of high-latitude ecosystems to global climate change, it is important that the scientific community consider how manipulative experiments can address and resolve ecosystem impacts and feedbacks to climate. A workshop sponsored by the Department of Energy, Office of Science was recently held at the University of Alaska, Fairbanks. The goal of the workshop was to highlight conclusions from observational and modeling studies about the response of arctic and subarctic ecosystems to a changing climate

  13. Middle Holocene rapid environmental changes and human adaptation in Greece

    NASA Astrophysics Data System (ADS)

    Lespez, Laurent; Glais, Arthur; Lopez-Saez, José-Antonio; Le Drezen, Yann; Tsirtsoni, Zoï; Davidson, Robert; Biree, Laetitia; Malamidou, Dimitra

    2016-03-01

    Numerous researchers discuss of the collapse of civilizations in response to abrupt climate change in the Mediterranean region. The period between 6500 and 5000 cal yr BP is one of the least studied episodes of rapid climate change at the end of the Late Neolithic. This period is characterized by a dramatic decline in settlement and a cultural break in the Balkans. High-resolution paleoenvironmental proxy data obtained in the Lower Angitis Valley enables an examination of the societal responses to rapid climatic change in Greece. Development of a lasting fluvio-lacustrine environment followed by enhanced fluvial activity is evident from 6000 cal yr BP. Paleoecological data show a succession of dry events at 5800-5700, 5450 and 5000-4900 cal yr BP. These events correspond to incursion of cold air masses to the eastern Mediterranean, confirming the climatic instability of the middle Holocene climate transition. Two periods with farming and pastural activities (6300-5600 and 5100-4700 cal BP) are evident. The intervening period is marked by environmental changes, but the continuous occurrence of anthropogenic taxa suggests the persistence of human activities despite the absence of archaeological evidence. The environmental factors alone were not sufficient to trigger the observed societal changes.

  14. The change of global terrestrial ecosystem net primary productivity (NPP) and its response to climate change in CMIP5

    NASA Astrophysics Data System (ADS)

    Li, Suosuo; Lü, Shihua; Zhang, Yongjun; Liu, Yuanpu; Gao, Yanhong; Ao, Yinhuan

    2015-07-01

    Using global terrestrial ecosystem observation and proxy data for net primary productivity (NPP), leaf area index (LAI), and climate data, we compared simulated NPP, LAI, and major climatic factors and explored the relationship between their variations in historical scenarios of ten Coupled Model Intercomparison Project (CMIP5) models. The results showed that global spatial patterns of the simulated terrestrial ecosystem and climate are consistent with proxy data, but the values have some differences for each model. Based on statistical analysis, the simulated climatic factors were found to be better than terrestrial ecosystem NPP and LAI, and the multi-model ensemble (MME) results were better than every single model. For the terrestrial ecosystem, air temperature (Ta) was found to be the major affecting factor, followed by precipitation, meaning the terrestrial ecosystem NPP and LAI are more related to Ta than precipitation. Meanwhile, surface downwelling shortwave radiation (Rsds) was found to inhibit the terrestrial ecosystem in almost all regions of the world. Between 1976 and 2005, precipitation had a slight increasing trend, Ta an obvious increasing trend, and Rsds a slight decreasing trend. The changes of precipitation, air temperature, and Rsds were favorable for the terrestrial ecosystem and for plant growth. Therefore, LAI and NPP showed an obvious increasing temporal trend, and the terrestrial ecosystem showed a positive response to climate change. All the model results showed NPP had an increasing temporal trend in the past 150 years, which also indicated that the terrestrial ecosystem has shown a positive response to climate change in that time period. In terms of the global average, the simulated NPP varied from 21.5 to 69.3 Pg C year-1, and the MME NPP is about 50.6, which was almost consistent with the International Geosphere Biosphere Program (IGBP) NPP result of 55.1 and Moderate Resolution Imaging Spectroradiometer (MODIS) NPP results of 60.5 Pg

  15. Phenological niches and the future of invaded ecosystems with climate change

    PubMed Central

    Wolkovich, Elizabeth M.; Cleland, Elsa E.

    2014-01-01

    In recent years, research in invasion biology has focused increasing attention on understanding the role of phenology in shaping plant invasions. Multiple studies have found non-native species that tend to flower distinctly early or late in the growing season, advance more with warming or have shifted earlier with climate change compared with native species. This growing body of literature has focused on patterns of phenological differences, but there is a need now for mechanistic studies of how phenology contributes to invasions. To do this, however, requires understanding how phenology fits within complex functional trait relationships. Towards this goal, we review recent literature linking phenology with other functional traits, and discuss the role of phenology in mediating how plants experience disturbance and stress—via climate, herbivory and competition—across the growing season. Because climate change may alter the timing and severity of stress and disturbance in many systems, it could provide novel opportunities for invasion—depending upon the dominant climate controller of the system, the projected climate change, and the traits of native and non-native species. Based on our current understanding of plant phenological and growth strategies—especially rapid growing, early-flowering species versus later-flowering species that make slower-return investments in growth—we project optimal periods for invasions across three distinct systems under current climate change scenarios. Research on plant invasions and phenology within this predictive framework would provide a more rigorous test of what drives invader success, while at the same time testing basic plant ecological theory. Additionally, extensions could provide the basis to model how ecosystem processes may shift in the future with continued climate change. PMID:24876295

  16. 13C AND 15N IN MICROARTHROPODS REVEAL LITTLE RESPONSE OF DOUGLAS-FIR ECOSYSTEMS TO CLIMATE CHANGE

    EPA Science Inventory

    Understanding ecosystem carbon (C) and nitrogen (N) cycling under global change requires experiments maintaining natural interactions among soil structure, soil communities, nutrient availability, and plant growth. In model Douglas-fir ecosystems maintained for five growing seaso...

  17. Evaluation of ecosystem services for good balance between climate change prevention and biodiversity conservation

    NASA Astrophysics Data System (ADS)

    Ito, A.; Adachi, M.; Yamagata, Y.; Suzuki, R.; Saigusa, N.; Sekine, H.

    2011-12-01

    For appropriate decision making in ecosystem management for global warming prevention and biodiversity conservation, a reliable and practical method to evaluate ecosystem services is necessary. For this purpose, we are conducting a project focusing on the evaluation of ecosystem services with a financial support from the Ministry of Environment, Japan, during the period from 2011 to 2013. The project is titled "Development of a method for evaluation of ecosystem services aiming at trade-off mitigation between climate change prevention and biodiversity conservation" (Environmental Research Fund, No. F-1101) and jointly conducted through collaboration among: the National Institute for Environmental Studies, the Japan-Agency for Marine-Earth Science and Technology, and Mitsubishi Research Institute. The objectives of the project include: (1) integration of observational data from field sites and satellites related to ecosystem functions, (2) development of a practical evaluation method of ecosystem services, and (3) contribution to mitigate conflicts between environmental mitigation options such as climate change prevention and biodiversity conservation. In this project, we have a couple of candidate sites in Asian region to conduct field studies including in situ observation of forest biomass, leaf area index, canopy structure, in conjunction with corresponding satellite observations. These data on functional traits will be related with important ecosystem services such as carbon sequestration and climate regulation, water supply, and genetic resource stemming from biodiversity.

  18. Regional zooplankton biodiversity provides limited buffering of pond ecosystems against climate change.

    PubMed

    Thompson, Patrick L; Shurin, Jonathan B

    2012-01-01

    1. Climate change and other human-driven environmental perturbations are causing reductions in biodiversity and impacting the functioning of ecosystems on a global scale. Metacommunity theory suggests that ecosystem connectivity may reduce the magnitude of these impacts if the regional species pool contains functionally redundant species that differ in their environmental tolerances. Dispersal may increase the resistance of local ecosystems to environmental stress by providing regional species with traits adapted to novel conditions. 2. We tested this theory by subjecting freshwater zooplankton communities in mesocosms that were either connected to or isolated from the larger regional species pool to a factorial manipulation of experimental warming and increased salinity. 3. Compensation by regional taxa depended on the source of stress. Warming tolerant regional taxa partially compensated for reductions in heat sensitive local taxa but similar compensation did not occur under increased salinity. 4. Dispersal-mediated species invasions dampened the effects of warming on summer net ecosystem productivity. However, this buffering effect did not occur in the fall or for periphyton growth, the only other ecosystem function affected by the stress treatments. 5. The results indicate that regional biodiversity can provide insurance in a dynamic environment but that the buffering capacity is limited to some ecosystem processes and sources of stress. Maintaining regional biodiversity and habitat connectivity may therefore provide some limited insurance for local ecosystems in changing environments, but is unable to impart resistance against all sources of environmental stress. PMID:21950456

  19. Predicting ecosystem shifts requires new approaches that integrate the effects of climate change across entire systems.

    PubMed

    Russell, Bayden D; Harley, Christopher D G; Wernberg, Thomas; Mieszkowska, Nova; Widdicombe, Stephen; Hall-Spencer, Jason M; Connell, Sean D

    2012-04-23

    Most studies that forecast the ecological consequences of climate change target a single species and a single life stage. Depending on climatic impacts on other life stages and on interacting species, however, the results from simple experiments may not translate into accurate predictions of future ecological change. Research needs to move beyond simple experimental studies and environmental envelope projections for single species towards identifying where ecosystem change is likely to occur and the drivers for this change. For this to happen, we advocate research directions that (i) identify the critical species within the target ecosystem, and the life stage(s) most susceptible to changing conditions and (ii) the key interactions between these species and components of their broader ecosystem. A combined approach using macroecology, experimentally derived data and modelling that incorporates energy budgets in life cycle models may identify critical abiotic conditions that disproportionately alter important ecological processes under forecasted climates. PMID:21900317

  20. Observing and diagnosing biological fluxes and canopy mechanisms with implications for climate change and ecosystem disturbance

    NASA Astrophysics Data System (ADS)

    Reed, David E.

    Improving our predictions of ecosystem responses is an important challenge in ecological science due to the increasing number of stresses applied to biological systems. The assumption that ecosystems are operating in steady-state conditions at annual and longer time scales is far too simple of a model as ecosystems are an integral part of the earth system. Anthropogenic and non-anthropogenic forces acting on ecosystems within the earth system are numerous and include broad external factors such as climate change to specific internal factors such as infestations causing disturbance. This research quantifies changes in biogeochemical cycling and increases understanding of the mechanisms that control these cycles across two major ecosystems of the intermountain west with the broad goal of better predictive power of ecosystem responses. Eddy covariance methods were used to quantify carbon, water and energy fluxes at two different field sites in sagebrush ecosystems and one field site in a lodgepole pine ecosystem, in south-east Wyoming and northern Colorado. These measurements were supported with environmental and micrometeorological measurements in order to better understand physical mechanisms and canopy processes that control these biological fluxes. Results from the sagebrush component of this dissertation show how semi-arid sagebrush canopies interact with the lower atmosphere in ways that can alter environmental control of water loss with changing leaf area. This feedback has large implications combined with the large land area of these ecosystems and predictions of a dryer and more variable precipitation regime in the future. At the higher elevation lodgepole pine site, the ecosystem is undergoing a major mortality disturbance due to native bark beetles. Interestingly, even with ˜80% mortality of the canopy, few changes are observed to carbon and water cycling, as well as water use efficiency and energy cycling at the ecosystem scale. This calls into question

  1. Variability in biomass yields of large marine ecosystems (LMEs) during climate change

    SciTech Connect

    Sherman, K. )

    1993-06-01

    Results of ecosystem studies relating to variations in biomass yields are examined in relation to principle driving forces including climate change, coastal pollution, habitat degradation, and overexploitation of living marine resources. Among the ecosystems compared with regard to the different prime driving forces, affecting sustainability of biomass yields, are the Black Sea, the Baltic Sea, the Barents Sea, Kuroshio Current, California Current, Great Barrier Reef, Gulf of Mexico, Yellow Sea, Icelandic Shelf, and Northeast US Shelf ecosystems. The designation and management of large marine ecosystems (LMEs) is, at present, an evolving scientific and geopolitical process. Sufficient progress has been made to allow for useful comparisons among different processes influencing large-scale changes in the biomass yields of LMEs. The most severely impacted LMEs are off the coasts of the continents.

  2. Decadal changes in climate and ecosystems in the North Atlantic Ocean and adjacent seas

    NASA Astrophysics Data System (ADS)

    Beaugrand, Grégory

    2009-04-01

    Climate change is unambiguous and its effects are clearly detected in all functional units of the Earth system. This study presents new analyses of sea-surface temperature changes and show that climate change is affecting ecosystems of the North Atlantic. Changes are seen from phytoplankton to zooplankton to fish and are modifying the dominance of species and the structure, the diversity and the functioning of marine ecosystems. Changes also range from phenological to biogeographical shifts and have involved in some regions of the Atlantic abrupt ecosystem shifts. These alterations reflect a response of pelagic ecosystems to a warmer temperature regime. Mechanisms are complex because they are nonlinear exhibiting tipping points and varying in space and time. Sensitivity of organisms to temperature changes is high, implicating that a small temperature modification can have sustained ecosystem effects. Implications of these changes for biogeochemical cycles are discussed. Two observed changes detected in the North Sea that could have opposite effects on carbon cycle are discussed. Increase in phytoplankton, as inferred from the phytoplankton colour index derived from the Continuous Plankton Recorder (CPR) survey, has been detected in the North Sea. This pattern has been accompanied by a reduction in the abundance of the herbivorous species Calanus finmarchicus. This might have reduced the grazing pressure and increase diatomaceous 'fluff', therefore carbon export in the North Sea. Therefore, it could be argued that the biological carbon pump might increase in this region with sea warming. In the meantime, however, the mean size of organisms (calanoid copepods) has dropped. Such changes have implications for the turnover time of biogenic carbon in plankton organisms and the mean residence time of particulate carbon they produce. The system characterising the warmer period is more based on recycling and less on export. The increase in the minimum turnover time

  3. On being a scientist in a rapidly changing world.

    PubMed

    Mandel, I D

    1996-02-01

    The practice of biological science has changed dramatically since mid-century, reshaped not only by a rapid series of landmark discoveries, but also by governmental directives, institutional policies, and public attitudes. Until 1964, the major influences were the mentor, who provided direction and indoctrination into the culture of science, and in dentistry, the newly established NIDR, which fueled the research engine with an expanding research and training program. The 1965-74 period witnessed the advent of the Institutional Review Board, an increased social involvement of biological scientists, and a recognition of the need for biological and physical safeguards in the conduct of research. The most turbulent years were 1975-89, when there was a confluence of animal rights activism and regulation, growing concerns with scientific fraud and publication malpractice, and the stresses and strains (and opportunities) resulting from the rapid expansion of the academic-industrial complex. The current period is characterized by rapid pace, high volume, and an increased depth and breadth of knowledge-a major change in scale in the conduct of science. It is an exciting time but one in which ethical issues are multiplying. Attention must be paid. PMID:8655785

  4. Changes in Marine Environments and Responses of Ecosystem Dynamics in the East Asian Pacific

    NASA Astrophysics Data System (ADS)

    Ogawa, Hiroshi; Saito, Hiroaki; Ju, Se-Jong

    2014-02-01

    At an international symposium on the marine systems of the Pacific region of East Asia, scientists concluded that changes in the ocean environment are having a significant effect on biogeochemical cycles and ecosystems and, consequently, on humans and the food supply. The meeting, the 6th China-Japan-Korea (CJK) Integrated Marine Biogeochemistry and Ecosystem Research symposium, was held in Japan at the University of Tokyo.

  5. Colloidal Particles that Rapidly Change Shape via Elastic Instabilities.

    PubMed

    Epstein, Eric; Yoon, Jaewon; Madhukar, Amit; Hsia, K Jimmy; Braun, Paul V

    2015-12-01

    The fabrication and properties of pH-responsive colloidal particles are reported, which change shape rapidly (less than 200 ms), nearly independent of the diffusion of the pH altering species that trigger their actuation, and far more rapid than their Brownian motion. These particles are mechanically bistable, as revealed by their hysteretic shape response. Finite element analysis (FEA) shows that mechanical hysteresis and bistability derives from the colloids' spherical curvature. Mechanical characterization of the bilayered polymers comprising the colloidal particles shows that viscoelastic relaxation plays a non-negligible role in limiting the shape switching rate; however, energy landscapes obtained from FEA simulations suggest that by tuning the elastic moduli and thicknesses of the constituent polymer layers, microparticles of the size shown here may be fabricated to actuate on timescales as fast as 1 μs. PMID:26449185

  6. Estuaries of the Greater Everglades Ecosystem: Laboratories of Long-term Change

    USGS Publications Warehouse

    Wingard, G.L.; Hudley, J.W.; Marshall, F.E.

    2010-01-01

    Restoring the greater Everglades ecosystem of south Florida is arguably the largest ecosystem restoration effort to date. A critical goal is to return more natural patterns of flow through south Florida wetlands and into the estuaries, but development of realistic targets requires acknowledgement that ecosystems are constantly evolving and changing in response to a variety of natural and human-driven stressors. Examination of ecosystems over long periods of time requires analysis of sedimentary records, such as those deposited in the wetlands and estuaries of south Florida. As sediment accumulates, it preserves information about the animals and plants that lived in the environment and the physical, chemical, and climatic conditions present. One of the methods used to interpret this information is paleoecology-the study of the ecology of previously living organisms. Paleoecologic investigations of south Florida estuaries provide quantitative data on historical variability of salinity and trends that may be applied to statistical models to estimate historical freshwater flow. These data provide a unique context to estimate future ecosystem response to changes related to restoration activities and predicted changes in sea level and temperature, thus increasing the likelihood of successful and sustainable ecosystem restoration.

  7. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate

    NASA Astrophysics Data System (ADS)

    Sun, Ge; Duan, Kai; Sun, Shanlei; Caldwell, Peter; Cohen, Erika; McNulty, Steven; Zhang, Yang

    2016-04-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This modeling study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in forest productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m-2 yr-1 (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr-1 (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 ℃) and precipitation (+17 ~ +51 mm yr-1). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services.

  8. Reorganization of an arid ecosystem in response to recent climate change

    PubMed Central

    Brown, James H.; Valone, Thomas J.; Curtin, Charles G.

    1997-01-01

    Natural ecosystems contain many individuals and species interacting with each other and with their abiotic environment. Such systems can be expected to exhibit complex dynamics in which small perturbations can be amplified to cause large changes. Here, we document the reorganization of an arid ecosystem that has occurred since the late 1970s. The density of woody shrubs increased 3-fold. Several previously common animal species went locally extinct, while other previously rare species increased. While these changes are symptomatic of desertification, they were not caused by livestock grazing or drought, the principal causes of historical desertification. The changes apparently were caused by a shift in regional climate: since 1977 winter precipitation throughout the region was substantially higher than average for this century. These changes illustrate the kinds of large, unexpected responses of complex natural ecosystems that can occur in response to both natural perturbations and human activities. PMID:11038570

  9. Modeling the response of plants and ecosystems to elevated CO sub 2 and climate change

    SciTech Connect

    Reynolds, J.F.; Hilbert, D.W.; Chen, Jia-lin; Harley, P.C.; Kemp, P.R.; Leadley, P.W.

    1992-03-01

    While the exact effects of elevated CO{sub 2} on global climate are unknown, there is a growing consensus among climate modelers that global temperature and precipitation will increase, but that these changes will be non-uniform over the Earth's surface. In addition to these potential climatic changes, CO{sub 2} also directly affects plants via photosynthesis, respiration, and stomatal closure. Global climate change, in concert with these direct effects of CO{sub 2} on plants, could have a significant impact on both natural and agricultural ecosystems. Society's ability to prepare for, and respond to, such changes depends largely on the ability of climate and ecosystem researchers to provide predictions of regional level ecosystem responses with sufficient confidence and adequate lead time.

  10. Modeling the response of plants and ecosystems to elevated CO{sub 2} and climate change

    SciTech Connect

    Reynolds, J.F.; Hilbert, D.W.; Chen, Jia-lin; Harley, P.C.; Kemp, P.R.; Leadley, P.W.

    1992-03-01

    While the exact effects of elevated CO{sub 2} on global climate are unknown, there is a growing consensus among climate modelers that global temperature and precipitation will increase, but that these changes will be non-uniform over the Earth`s surface. In addition to these potential climatic changes, CO{sub 2} also directly affects plants via photosynthesis, respiration, and stomatal closure. Global climate change, in concert with these direct effects of CO{sub 2} on plants, could have a significant impact on both natural and agricultural ecosystems. Society`s ability to prepare for, and respond to, such changes depends largely on the ability of climate and ecosystem researchers to provide predictions of regional level ecosystem responses with sufficient confidence and adequate lead time.

  11. Information Needs Assessment for Coastal and Marine Management and Policy: Ecosystem Services Under Changing Climatic, Land Use, and Demographic Conditions

    NASA Astrophysics Data System (ADS)

    Goldsmith, Kaitlin A.; Granek, Elise F.; Lubitow, Amy

    2015-12-01

    Changing climatic, demographic, and land use conditions are projected to alter the provisioning of ecosystem services in estuarine, coastal, and nearshore marine ecosystems, necessitating mitigation and adaptation policies and management. The current paradigm of research efforts occurring in parallel to, rather than in collaboration with, decision makers will be insufficient for the rapid responses required to adapt to and mitigate for projected changing conditions. Here, we suggest a different paradigm: one where research begins by engaging decision makers in the identification of priority data needs (biophysical, economic, and social). This paper uses synthesized interview data to provide insight into the varied demands for scientific research as described by decision makers working on coastal issues in Oregon, USA. The findings highlight the need to recognize (1) the differing framing of ecosystem services by decision makers versus scientists; and (2) the differing data priorities relevant to inland versus coastal decision makers. The findings further serve to highlight the need for decision makers, scientists, and funders to engage in increased communication. This research is an important first step in advancing efforts toward evidence-based decision making in Oregon and provides a template for further research across the US.

  12. An Integrated Coral Reef Ecosystem Model to Support Resource Management under a Changing Climate.

    PubMed

    Weijerman, Mariska; Fulton, Elizabeth A; Kaplan, Isaac C; Gorton, Rebecca; Leemans, Rik; Mooij, Wolf M; Brainard, Russell E

    2015-01-01

    Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) biomass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers

  13. An Integrated Coral Reef Ecosystem Model to Support Resource Management under a Changing Climate

    PubMed Central

    Weijerman, Mariska; Fulton, Elizabeth A.; Kaplan, Isaac C.; Gorton, Rebecca; Leemans, Rik; Mooij, Wolf M.; Brainard, Russell E.

    2015-01-01

    Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) biomass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers

  14. Realizing the Potential of Ecosystem Services: A Framework for Relating Ecological Changes to Economic Benefits

    NASA Astrophysics Data System (ADS)

    Wainger, Lisa; Mazzotta, Marisa

    2011-10-01

    Increasingly government agencies are seeking to quantify the outcomes of proposed policy options in terms of ecosystem service benefits, yet conflicting definitions and ad hoc approaches to measuring ecosystem services have created confusion regarding how to rigorously link ecological change to changes in human well-being. Here, we describe a step-by-step framework for producing ecological models and metrics that can effectively serve an economic-benefits assessment of a proposed change in policy or management. A focus of the framework is developing comparable units of ecosystem goods and services to support decision-making, even if outcomes cannot be monetized. Because the challenges to translating ecological changes to outcomes appropriate for economic analyses are many, we discuss examples that demonstrate practical methods and approaches to overcoming data limitations. The numerous difficult decisions that government agencies must make to fairly use and allocate natural resources provides ample opportunity for interdisciplinary teams of natural and social scientists to improve methods for quantifying changes in ecosystem services and their effects on human well-being. This framework is offered with the intent of promoting the success of such teams as they support managers in evaluating the equivalency of ecosystem service offsets and trades, establishing restoration and preservation priorities, and more generally, in developing environmental policy that effectively balances multiple perspectives.

  15. Global environmental change effects on ecosystems: the importance of land-use legacies.

    PubMed

    Perring, Michael P; De Frenne, Pieter; Baeten, Lander; Maes, Sybryn L; Depauw, Leen; Blondeel, Haben; Carón, María M; Verheyen, Kris

    2016-04-01

    One of the major challenges in ecology is to predict how multiple global environmental changes will affect future ecosystem patterns (e.g. plant community composition) and processes (e.g. nutrient cycling). Here, we highlight arguments for the necessary inclusion of land-use legacies in this endeavour. Alterations in resources and conditions engendered by previous land use, together with influences on plant community processes such as dispersal, selection, drift and speciation, have steered communities and ecosystem functions onto trajectories of change. These trajectories may be modulated by contemporary environmental changes such as climate warming and nitrogen deposition. We performed a literature review which suggests that these potential interactions have rarely been investigated. This crucial oversight is potentially due to an assumption that knowledge of the contemporary state allows accurate projection into the future. Lessons from other complex dynamic systems, and the recent recognition of the importance of previous conditions in explaining contemporary and future ecosystem properties, demand the testing of this assumption. Vegetation resurvey databases across gradients of land use and environmental change, complemented by rigorous experiments, offer a means to test for interactions between land-use legacies and multiple environmental changes. Implementing these tests in the context of a trait-based framework will allow biologists to synthesize compositional and functional ecosystem responses. This will further our understanding of the importance of land-use legacies in determining future ecosystem properties, and soundly inform conservation and restoration management actions. PMID:26546049

  16. Degraded States, Novel Ecosystems, or Reconfigured Landscapes: How Should We View Ecosystem Change in a Changing World?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change is predicted to cause gradual warming and changes in the amount and distribution of rainfall. Thus, the default assumption should be that attributes of rangelands will change, rather than stay as they have been. The talks in this symposium have described what may happen to rangeland c...

  17. New Challenges for Women Physicists in a Rapidly Changing China

    NASA Astrophysics Data System (ADS)

    Wu, Ling-An

    2005-10-01

    With the tremendous growth in China's economy, young people now enjoy a much wider choice of careers; but women are also beginning to face new challenges, such as discrimination in employment and retirement policies. The ratio of women in physics in universities has remained more or less constant, but that in research institutes has decreased in recent years, although the ratio of young women awarded research grants seems to be on the rise. More effort must be exerted to guarantee equal opportunity for women physicists, young and old, in a rapidly changing society.

  18. DEVELOPING TOOLS FOR EVALUATION OF INTERACTIONS BETWEEN GLOBAL CHANGE STRESSORS AND ECOSYSTEM FUNCTIONING

    EPA Science Inventory

    Case studies in key selected coral reefs and watersheds will be completed to provide scientific data, concepts and models that describe the responses of the functioning of these ecosystems to global change stressors. The studies will focus on relating global changes to local and...

  19. Linking populations to landscapes: richness scenarios resulting from changes in the dynamics of an ecosystem engineer.

    PubMed

    Wright, Justin P

    2009-12-01

    Predicting the effects of the loss of individual species on diversity represents one of the primary challenges facing community ecology. One pathway by which organisms of one species affect the distribution of species is ecosystem engineering. Changes in the dynamics of ecosystem engineers that lead to changes in the distribution of the patches of altered habitat are likely to lead to changes in diversity. I link data on the distribution of plant species found in the riparian zone of the Adirondacks (New York, USA) in patches modified by beaver and in unmodified forest patches to a model connecting the dynamics of ecosystem engineers to the dynamics of the patches that they create. These analyses demonstrate that changes in key parameters of the model, such as decreases in beaver colonization rates and rate of patch abandonment, lead to changes in species richness of up to 45% at the landscape scale, and that these changes are likely to occur over long time scales. This general approach of linking the population dynamics or behavior of a single species to changes in species richness at the landscape scale provides a means for both testing the importance of ecosystem engineering in different systems and developing scenarios to predict how changes in the dynamics of a single species are likely to affect species richness. PMID:20120810

  20. Impact of forest seral stage on use of ant communities for rapid assessment of terrestrial ecosystem health.

    PubMed

    Wike, Lynn D; Martin, F Douglas; Paller, Michael H; Nelson, Eric A

    2010-01-01

    Bioassessment evaluates ecosystem health by using the responses of a community of organisms that integrate all aspects of the ecosystem. A variety of bioassessment methods have been applied to aquatic ecosystems; however, terrestrial methods are less advanced. The objective of this study was to examine baseline differences in ant communities at different seral stages from clear cut to mature pine plantation as a precursor to developing a broader terrestrial bioassessment protocol. Comparative sampling was conducted at nine sites having four seral stages: clearcut, 5 year recovery, 15 year recovery, and mature stands. Soil and vegetation data were also collected at each site. Ants were identified to genus. Analysis of the ant data indicated that ants respond strongly to habitat changes that accompany ecological succession in managed pine forests, and both individual genera and ant community structure can be used as indicators of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in mature seral stages was likely related to conditions on the forest floor favoring litter dwelling and cold climate specialists. While ants may be very useful in identifying environmental stress in managed pine forests, adjustments must be made for seral stage when comparing impacted and unimpacted forests. PMID:20673195

  1. Impact of Forest Seral Stage on use of Ant Communities for Rapid Assessment of Terrestrial Ecosystem Health

    PubMed Central

    Wike, Lynn D.; Martin, F. Douglas; Paller, Michael H.; Nelson, Eric A.

    2010-01-01

    Bioassessment evaluates ecosystem health by using the responses of a community of organisms that integrate all aspects of the ecosystem. A variety of bioassessment methods have been applied to aquatic ecosystems; however, terrestrial methods are less advanced. The objective of this study was to examine baseline differences in ant communities at different seral stages from clear cut to mature pine plantation as a precursor to developing a broader terrestrial bioassessment protocol. Comparative sampling was conducted at nine sites having four seral stages: clearcut, 5 year recovery, 15 year recovery, and mature stands. Soil and vegetation data were also collected at each site. Ants were identified to genus. Analysis of the ant data indicated that ants respond strongly to habitat changes that accompany ecological succession in managed pine forests, and both individual genera and ant community structure can be used as indicators of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in mature seral stages was likely related to conditions on the forest floor favoring litter dwelling and cold climate specialists. While ants may be very useful in identifying environmental stress in managed pine forests, adjustments must be made for seral stage when comparing impacted and unimpacted forests. PMID:20673195

  2. Baltic Sea ecosystem-based management under climate change: Synthesis and future challenges.

    PubMed

    Blenckner, Thorsten; Österblom, Henrik; Larsson, Per; Andersson, Agneta; Elmgren, Ragnar

    2015-06-01

    Ecosystem-based management (EBM) has emerged as the generally agreed strategy for managing ecosystems, with humans as integral parts of the managed system. Human activities have substantial effects on marine ecosystems, through overfishing, eutrophication, toxic pollution, habitat destruction, and climate change. It is important to advance the scientific knowledge of the cumulative, integrative, and interacting effects of these diverse activities, to support effective implementation of EBM. Based on contributions to this special issue of AMBIO, we synthesize the scientific findings into four components: pollution and legal frameworks, ecosystem processes, scale-dependent effects, and innovative tools and methods. We conclude with challenges for the future, and identify the next steps needed for successful implementation of EBM in general and specifically for the Baltic Sea. PMID:26022332

  3. INCREASE - an Integrated Network on Climate Change REsearch Activities on Shrubland Ecosystems

    NASA Astrophysics Data System (ADS)

    Kappel Schmidt, Inger; Steenberg Larsen, Klaus; Beier, Claus; Tietema, Albert; Emmett, Bridget; De Angelis, Paolo; Duce, Pierpaolo; Cesaraccio, Carla; Spano, Donatella; Kroel-Dulay, Gyuri; Jones, Davey

    2013-04-01

    Climate change poses a serious challenge for the scientific communities to develop new concepts for research and modeling to provide better and more realistic answers and predictions of what the impact will be. INCREASE is an EU-funded research infrastructure based upon large scale field experiments with non-intrusive manipulations of temperature and precipitation since 1999. The experiments are placed in vulnerable scrubland ecosystems across Europe. Shrubland ecosystems were chosen because they represent an important natural resource, which are known to be sensitive to observed changes in environmental pressures. The experiments combine 2 different approaches to study climate effects on ecosystems. The first approach is known as "space for time" substitution, where the long term effect of a pressure on an ecosystem at any particular site is studied by moving to another site along temperature and precipitation gradients. This was done by carrying out the same studies in comparable ecosystems in UK, Denmark, the Netherlands, Hungary, Spain and Italy - which are naturally exposed to large differences in the climatic conditions. The other approach applied is "ecosystem manipulations", which means that the ecosystem is exposed to the changes in the field by realistic manipulations of temperature and water and in one experiment in combination with CO2. This combination of gradients and experimental manipulation increases the potential for evaluating the generality of the observed responses to the changes in the climatic drivers. Within INCREASE we improve the technology and methodology for studies of climate change effects on European shrublands and stimulate collaboration within the scientific community around climate manipulation experiments. In addition, data and results from the research infrastructures were collected into an integrated database (INCREASE DB) with the aim to improve capacities in the protection, management and storage of data and to provide a web

  4. Ecohydrology of adjacent sagebrush and lodgepole pine ecosystems: the consequences of climate change and disturbance

    USGS Publications Warehouse

    Bradford, John B.; Schlaepfer, Daniel R.; Lauenroth, William K.

    2014-01-01

    Sagebrush steppe and lodgepole pine forests are two of the most widespread vegetation types in the western United States and they play crucial roles in the hydrologic cycle of these water-limited regions. We used a process-based ecosystem water model to characterize the potential impact of climate change and disturbance (wildfire and beetle mortality) on water cycling in adjacent sagebrush and lodgepole pine ecosystems. Despite similar climatic and topographic conditions between these ecosystems at the sites examined, lodgepole pine, and sagebrush exhibited consistent differences in water balance, notably more evaporation and drier summer soils in the sagebrush and greater transpiration and less water yield in lodgepole pine. Canopy disturbances (either fire or beetle) have dramatic impacts on water balance and availability: reducing transpiration while increasing evaporation and water yield. Results suggest that climate change may reduce snowpack, increase evaporation and transpiration, and lengthen the duration of dry soil conditions in the summer, but may have uncertain effects on drainage. Changes in the distribution of sagebrush and lodgepole pine ecosystems as a consequence of climate change and/or altered disturbance regimes will likely alter ecosystem water balance.

  5. How important is diversity for capturing environmental-change responses in ecosystem models?

    NASA Astrophysics Data System (ADS)

    Prowe, A. E. F.; Pahlow, M.; Dutkiewicz, S.; Oschlies, A.

    2014-06-01

    Marine ecosystem models used to investigate how global change affects ocean ecosystems and their functioning typically omit pelagic plankton diversity. Diversity, however, may affect functions such as primary production and their sensitivity to environmental changes. Here we use a global ocean ecosystem model that explicitly resolves phytoplankton diversity by defining subtypes within four phytoplankton functional types (PFTs). We investigate the model's ability to capture diversity effects on primary production under environmental change. An idealized scenario with a sudden reduction in vertical mixing causes diversity and primary-production changes that turn out to be largely independent of the number of coexisting phytoplankton subtypes. The way diversity is represented in the model provides a small number of niches with respect to nutrient use in accordance with the PFTs defined in the model. Increasing the number of phytoplankton subtypes increases the resolution within the niches. Diversity effects such as niche complementarity operate between, but not within PFTs, and are constrained by the variety of traits and trade-offs resolved in the model. The number and nature of the niches formulated in the model, for example via trade-offs or different PFTs, thus determines the diversity effects on ecosystem functioning captured in ocean ecosystem models.

  6. Ecosystem Diversity and Heterogeneity Determine the Resilience of the Amazon to Climate Change

    NASA Astrophysics Data System (ADS)

    Moorcroft, P. R.; Levine, N. M.; Longo, M.; Powell, T.; Zhang, K.

    2015-12-01

    Amazon Forests, which play a vital role in global water, energy and carbon cycling, are predicted to experience both longer and more intensive dry seasons by the end of the 21st century. However, the climate sensitivity of this ecosystem remains uncertain: several studies have predicted large-scale die-back of the Amazon, while several more recent studies predict that the biome will remain largely intact. In this study we use an individual-based terrestrial ecosystem model to explore the sensitivity and ecological resilience of these forests to changes in climate. Our results show that water stress operating at the scale of individual plants, combined with spatial variation in soil texture, strongly influence the ecosystem's resilience to changes in dry season length. Further analysis shows that two key traits influencing the climatic sensitivity of individuals within the plant canopy are their phenology and hydraulic architecture. In contrast to existing predictions of either stability or catastrophic biomass loss, our analyses indicate that, as a result of these effects of ecosystem diversity and heterogeneity, the Amazon forest's response to a drying regional climate is likely to be an immediate, graded, heterogeneous transition from high biomass moist forests to transitional dry forests and woody savannah ecosystems. While fire, logging and other anthropogenic disturbances may exacerbate the impacts of climate-induced changes, our analysis indicates considerable spatial variation in the vulnerability of Amazon forests to human induced climate change.

  7. Opportunities to Improve Urban and Ecosystem Adaptation to Climate Change Through Conservation of Green Space.

    NASA Astrophysics Data System (ADS)

    Heller, N. E.

    2014-12-01

    The conservation of biotic communities in urbanized ecosystems is critical in light of heightened vulnerability due to climate change. Conservation of large open spaces around cities and smaller 'green' spaces within cities - such as forest patches and wetlands - has the capacity to diminish the vulnerability of human communities to higher temperatures, water shortages, increased flooding and other impacts of climate change. In addition, native species need to migrate to track their climate niches and the chances of successful migration will be increased if species have access to habitat throughout the landscape. Thus there is a strong rationale to do more conservation and restoration for both ecosystem and urban adaptation to climate change. Despite this alignment, planning efforts in the urban and ecosystem sectors are rarely done synergistically. As a result it is not clear how well plans will achieve biodiversity along with other ecosystem services goals. In this talk, I will discuss how urban adaptation planning can better align with ecosystem adaptation planning by drawing on research exploring sustainability plans and urban ecology in US cities, including work conducted in the San Francisco Bay Area by the Terrestrial Biodiversity and Climate Change Collaborative (TBC3). This research shows that there are considerable opportunities for linking agendas across sectors in ways that could yield multiple benefits. There are however both social and ecological challenges. In some cases difficult choices will need to be made about which values and services are most important, or where in the landscape different values should be prioritized.

  8. Integrated trend assessment of ecosystem changes in the Limfjord (Denmark): Evidence of a recent regime shift?

    NASA Astrophysics Data System (ADS)

    Tomczak, Maciej T.; Dinesen, Grete E.; Hoffmann, Erik; Maar, Marie; Støttrup, Josianne G.

    2013-01-01

    An integrated ecosystem assessment was carried out for the Limfjord over the period from 1984 to 2008 to describe changes in ecosystem structure and potentially important drivers. The Limfjord is a eutrophic transitional Danish fjord system with the main inflow from the North Sea in the west and main outflow to the Kattegat in the east. We showed that from 1990 to 1995, the ecosystem structure shifted from dominance by demersal fish species (eelpout, whiting, flounder, plaice) to that of pelagic fish species (sprat, herring, sticklebacks), small-bodied fish species (black goby, pipefish), jellyfish, common shore crab, starfish and blue mussels. We interpret this change as a regime shift that showed a similar temporal pattern to regime shifts identified in adjacent seas. The observed changes in trophic interactions and food web reorganisation suggested a non-linear regime shift. The analyses further showed the regime shift to be driven by a combination of anthropogenic pressures and possible interplay with climatic disturbance.

  9. A salinity projection model for determining impacts of climate change on river ecosystems in Taiwan

    NASA Astrophysics Data System (ADS)

    Suen, Jian-Ping; Lai, Hung-Nien

    2013-06-01

    Climate change would impact ecosystems in many different ways, including alteration of hydrological conditions. The purpose of the research described in this paper is to determine the potential impacts of climate change on river ecosystems by mathematically simulating changes in salinity. Salinity, which is highly related to the relative abundance of particular organisms in the river and estuary wetland ecosystems, is a good indicator for impacts of climate change. The salinity projection model described in this research uses back-propagation neural networks, a robust method to simulate water quality conditions, to simulate salinity changes at several locations in a Taiwanese river. The results show the increase of salinity among all study sites under all climate change scenarios. We relate this to aquatic organism population effects by noting the threats of increased salinity on blockages or competition in some areas among species. Riparian mangroves and wetland plants near the river mouth may face increased stress due to the increased salinity concentrations. This tool allows a potential threat caused by salinity change to be analyzed as precautionary information for water resources and river ecosystem management.

  10. Rapid and persistent change of microbial community and gross N turnover under experimentally simulated climate change conditions in alpine grassland

    NASA Astrophysics Data System (ADS)

    Wang, Changhui; Chen, Zhe; Unteregelsbacher, Sebastian; Gschwendtner, Silvia; Schloter, Michael; Butterbach-Bahl, Klaus; Dannenmann, Michael

    2013-04-01

    evidence for a rapid but persistent change of the microbial community under expected climate change conditions, leading to strongly increased N mineralization and nitrification with associated high risks for N losses along hydrological and gaseous pathways. Furthermore, our study demonstrates that archaea are key players for nitrification in the investigated ecosystem, and that molecular approaches to determine N cycle gene abundance may have a so far overlooked and unexpectedly high power to predict gross rates of N turnover. Finally, we show that winter is a so far rarely considered key period for understanding seasonal patterns and annual sum of N turnover in alpine grasslands.

  11. Evolutionary traps and range shifts in a rapidly changing world.

    PubMed

    Hale, Robin; Morrongiello, John R; Swearer, Stephen E

    2016-06-01

    Humans are altering the environment at an unprecedented rate. Although behavioural plasticity has allowed many species to respond by shifting their ranges to more favourable conditions, these rapid environmental changes may cause 'evolutionary traps', whereby animals mistakenly prefer resources that reduce their fitness. The role of evolutionary traps in influencing the fitness consequences of range shifts remains largely unexplored. Here, we review these interactions by considering how climate change may trigger maladaptive developmental pathways or increase the probability of animals encountering traps. We highlight how traps could selectively remove some phenotypes and compromise population persistence. We conclude by highlighting emerging areas of research that would improve our understanding of when interactions between evolutionary traps and range shifts are likely to be most detrimental to animals. PMID:27330167

  12. Transformation of Peat-Forming Ecosystems in a Changing Climate and Landscape on the Western Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Yu, Z.; Loisel, J.; Beilman, D.; Cleary, K.

    2014-12-01

    The western Antarctic Peninsula (WAP) is one of three regions that have experienced the greatest warming on Earth over the recent decades. This warming has caused widespread glacier retreat and expansion of ice-free land areas. However, responses of terrestrial ecosystems to these rapid climate and landscape changes are still poorly understood. Here we used paleo records of climate and ecosystem reconstructions during the last millennium from peats on the WAP to understand climate-cryosphere-ecosystem connections. Continuing retreat of ice and permanent snow at Bonaparte Point on Anvers Island near Palmer Station and on Galindez Island near Vernadsky Station around 65°S latitude has recently exposed numerous entombed mosses and intact peatbank ecosystems that have been buried under ice and snow since the cold Little Ice Age (LIA). Radiocarbon dating indicates ages of 850-600 cal yr BP from re-exposed moss samples from near retreating ice (n=9 dates) and of 100 cal yr BP from near shrinking snow (n=5 dates). This age difference suggests that initial climate cooling and subsequent ice advance overran peatbanks immediately below the ice margin at the onset of the LIA, followed by permanent snow expansion often from low elevation upslope at the end of the LIA. Furthermore, detailed macrofossil and pollen analysis of a 35-cm-long peat core from a moss peatbank on nearby mainland Antarctic Peninsula show dramatic shifts from a waterlogged peatland dominated by pure stands of Antarctic hairgrass (Deschampsia antarctica) before the LIA to an aerobic peatbank dominated by erect mosses Polytrichum strictum and Chorisodontium aciphyllum afterwards. At present the nearest known occurrence of Deschampsia "bog peats" is in South Georgia, about 1900 km north at 54°S, a location having a mean annual temperature 6°C higher than the study region on the WAP. If we use this modern spatial relationship as an analogue, then this suggests that the pre-LIA climate was much warmer than

  13. Changes in Ecosystem Services and related Livelihoods in the Mekong Delta: vulnerabilities and adaptation strategies

    NASA Astrophysics Data System (ADS)

    Sebesvari, Z.; Renaud, F. G.

    2014-12-01

    The Mekong Delta (Vietnam) is highly vulnerable to the many impacts of global environmental change as well as to the accelerating anthropogenic changes in the catchment and in the delta itself. Today the delta is an agricultural landscape controlled by engineering structures such as channels, dykes, embankments, and sluice gates. These structures have been constructed gradually over the last 200 years mainly for irrigation and flood control in the upper part of the delta and to control saline intrusion in the coastal areas. Recent changes in the hydrology mainly driven by upstream hydropower development on the mainstream and the tributaries of the Mekong will likely have far reaching impacts on the delta´s social-ecological systems through changes in e.g. sedimentation processes, nutrient transport as well as the health of aquatic ecosystems. Further threats to the delta include sea level rise and an increase in seasonal rainfall variability leading to an increase in flood variability. These changes affect the lives of millions of low-income inhabitants who depend on the ecosystem services provided by the Mekong for their livelihoods and sustenance. Since the changes in ecosystem service provision are occurring relatively fast while the resource dependency of the delta population is very high, adaptation becomes a challenge. An assessment of livelihood dependencies on ecosystem services requires an understanding of ecosystem services affected by different drivers of change, as well as of the types of livelihoods likely to be jeopardized as a result of these changes. We will present main ecosystem services supporting specific livelihoods, discuss how they are threatened, and analyse the merits of potential solutions. Options based solely on grey infrastructure might be problematic on the long term while an integration of ecosystem based solution such as a (re)adaptation of agricultural production systems to floods in the upper delta might be a more sustainable

  14. Hydrothermal iron flux variability following rapid sea level changes

    NASA Astrophysics Data System (ADS)

    Middleton, Jennifer L.; Langmuir, Charles H.; Mukhopadhyay, Sujoy; McManus, Jerry F.; Mitrovica, Jerry X.

    2016-04-01

    Sea level changes associated with Pleistocene glacial cycles have been hypothesized to modulate melt production and hydrothermal activity at ocean ridges, yet little is known about fluctuations in hydrothermal circulation on time scales longer than a few millennia. We present a high-resolution record of hydrothermal activity over the past 50 ka using elemental flux data from a new sediment core from the Mir zone of the TAG hydrothermal field at 26°N on the Mid-Atlantic Ridge. Mir sediments reveal sixfold to eightfold increases in hydrothermal iron and copper deposition during the Last Glacial Maximum, followed by a rapid decline during the sea level rise associated with deglaciation. Our results, along with previous observations from Pacific and Atlantic spreading centers, indicate that rapid sea level changes influence hydrothermal output on mid-ocean ridges. Thus, climate variability may discretize volcanic processing of the solid Earth on millennial time scales and subsequently stimulate variability in biogeochemical interactions with volcanic systems.

  15. Challenges for Ecosystem Services Provided by Coral Reefs In the Face of Climate Change

    NASA Astrophysics Data System (ADS)

    Kikuchi, R. K.; Elliff, C. I.

    2014-12-01

    Coral reefs provide many ecosystem services of which coastal populations are especially dependent upon, both in cases of extreme events and in daily life. However, adaptation to climate change is still relatively unknown territory regarding the ecosystem services provided by coastal environments, such as coral reefs. Management strategies usually consider climate change as a distant issue and rarely include ecosystem services in decision-making. Coral reefs are among the most vulnerable environments to climate change, considering the impact that increased ocean temperature and acidity have on the organisms that compose this ecosystem. If no actions are taken, the most likely scenario to occur will be of extreme decline in the ecosystem services provided by coral reefs. Loss of biodiversity due to the pressures of ocean warming and acidification will lead to increased price of seafood products, negative impact on food security, and ecological imbalances. Also, sea-level rise and fragile structures due to carbonate dissolution will increase vulnerability to storms, which can lead to shoreline erosion and ultimately threaten coastal communities. Both these conditions will undoubtedly affect recreation and tourism, which are often the most important use values in the case of coral reef systems. Adaptation strategies to climate change must take on an ecosystem-based approach with continuous monitoring programs, so that multiple ecosystem services are considered and not only retrospective trends are analyzed. Brazilian coral reefs have been monitored on a regular basis since 2000 and, considering that these marginal coral reefs of the eastern Atlantic are naturally under stressful conditions (e.g. high sedimentation rates), inshore reefs of Brazil, such as those in Tinharé-Boipeba, have shown lower vitality rates due to greater impacts from the proximity to the coastal area (e.g. pollution, overfishing, sediment run-off). This chronic negative impact must be addressed

  16. Mechanisms driving change: altered species interactions and ecosystem function through global warming.

    PubMed

    Traill, Lochran W; Lim, Matthew L M; Sodhi, Navjot S; Bradshaw, Corey J A

    2010-09-01

    1. We review the mechanisms behind ecosystem functions, the processes that facilitate energy transfer along food webs, and the major processes that allow the cycling of carbon, oxygen and nitrogen, and use case studies to show how these have already been, and will continue to be, altered by global warming. 2. Increased temperatures will affect the interactions between heterotrophs and autotrophs (e.g. pollination and seed dispersal), and between heterotrophs (e.g. predators-prey, parasites/pathogens-hosts), with generally negative ramifications for important ecosystem services (functions that provide direct benefit to human society such as pollination) and potential for heightened species co-extinction rates. 3. Mitigation of likely impacts of warming will require, in particular, the maintenance of species diversity as insurance for the provision of basic ecosystem services. Key to this will be long-term monitoring and focused research that seek to maintain ecosystem resilience in the face of global warming. 4. We provide guidelines for pursuing research that quantifies the nexus between ecosystem function and global warming. These include documentation of key functional species groups within systems, and understanding the principal outcomes arising from direct and indirect effects of a rapidly warming environment. Localized and targeted research and monitoring, complemented with laboratory work, will determine outcomes for resilience and guide adaptive conservation responses and long-term planning. PMID:20487086

  17. Analysis of Climate Change Effects on Baseflow Index and Groundwater Dependent Ecosystems

    NASA Astrophysics Data System (ADS)

    Kang, H.

    2015-12-01

    Severe water shortages have been observed globally and the damage from climate change is predicted to increase consistently. Especially, groundwater which accounts for 95% of water resources that ecosystems rely on is very important. In order to protect the health of ecosystems from groundwater, research on climate change adaptation is necessary. This research aims at analyzing the effects of baseflow on Groundwater Dependent Ecosystems(GDEs) through Baseflow Index(BFI) utilizing run-off discharge according to the climate change. In order to analyze the effects on GDEs, Nakdong basin was selected for demonstration. So as to compute the baseflow in the basin, Soil and Water Assessment Tool(SWAT) was employed. This research compared and analyzed distribution of BFI over the past 30 years and expected BFI in connection with climate change. RCP 8.5 provided by IPCC was utilized and the result showed that changes of BFI in four periods, P1(1980-2009), F1(2010-2039), F2(2040-2069) and F3(2070-2099), varied according to weather conditions. So as to analyze the correlation between baseflow each period and GDEs, this research employed ecosystems health index and carried out correlation analysis according to each GDEs. Analysis showed that correlation between baseflow and Benthic Macro-invertebrate(BMI) was over R2 0.7 and correlation to the rest was low. This means BMI prove to be sensitive in BFI. The purpose of this research is to figure out the characteristics of baseflow about the impact of climate change and analyze the impact of baseflow on GDEs through the correlation analysis between baseflow and ecosystems health index. BMI has high correlation to baseflow and the rest do not. Generally, however, GDEs are hugely inter-related to water so that baseflow which accounts for over 40 percent cannot be excluded. Therefore, based on this research, management system on baseflow ought to be established with more endeavors to protect and preserve ecosystems.

  18. Impact of land use and land cover changes on ecosystem services in Menglun, Xishuangbanna, Southwest China.

    PubMed

    Hu, Huabin; Liu, Wenjun; Cao, Min

    2008-11-01

    Changing the landscape has serious environmental impacts affecting the ecosystem services, particularly in the tropics. In this paper, we report changes in ecosystem services in relation to land use and land cover over an 18-year period (1988--2006) in the Menglun Township, Xishuangbanna, Southwest China. We used Landsat TM/ETM and Quickbird data sets to estimate changes in ten land use and land cover categories, and generalized value coefficients to estimate changes in the ecosystem services provided by each land category. The results showed that over the 18-year period, the land use and land cover in the study area experienced significant changes. Rubber plantations increased from 12.10% of total land cover to 45.63%, while forested area and swidden field decreased from 48.73 and 13.14 to 27.57 and 0.46%, respectively. During this period, the estimated value of ecosystem services dropped by US $11.427 million (approximately 27.73%). Further analysis showed that there were significant changes in ecological functions such as nutrient cycling, erosion control, climate regulation and water treatment as well as recreation; the obvious increase in the ecological function is provision of raw material (natural rubber). Our findings conclude that an abrupt shift in land use from ecologically important tropical forests and traditionally managed swidden fields to large-scale rubber plantations result in a great loss of ecosystem services in this area. Further, the study suggests that provision of alternative economic opportunities would help in maintaining ecosystem services and for an appropriate compensation mechanisms need to be established based on rigorous valuation. PMID:18157650

  19. Biodiversity and ecosystems: Change at the community level

    NASA Astrophysics Data System (ADS)

    Edwards, Martin

    2011-11-01

    Some commercial fish species of the northeast Atlantic Ocean have relocated in response to warming. The impact of warming on marine assemblages in the region may already be much greater than appreciated, however, with over 70% of common demersal fish species responding through changes in abundance, rather than range.

  20. Regional Climate Variations and Change for Terrestrial Ecosystems Workshop Review

    EPA Science Inventory

    North Carolina State University, the University of North Carolina at Chapel Hill, and the U.S. Environmental Protection Agency, in partnership with the U.S. Department of the Interior Southeast Climate Science Center (SECSC), hosted the Regional Climate Variations and Change for ...

  1. EFFECTS OF GLOBAL CHANGE ON CORAL REEF ECOSYSTEMS

    EPA Science Inventory

    Corals and coral reefs of the Caribbean and through the world are deteriorating at an accelerated rate. Several stressors are believed to contrbute to this decline, including global changes in atmospheric gases and land use patterns. In particular, warmer water temperatures and...

  2. Tropical vegetation evidence for rapid sea level changes associated with Heinrich Events

    NASA Astrophysics Data System (ADS)

    González, Catalina; Dupont, Lydie M.

    2010-03-01

    A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3. Rapid and abrupt expansions of salt marsh vegetation in tropical South America are associated with north Atlantic Heinrich Events stadials (HE-stadials). Intervals of salt marsh expansion have an internal structure, which consists of a recurrent alternation of species that starts with pollen increments of Chenopodiaceae, that are followed by increments of grasses, and subsequently by increments of Cyperaceae. This pattern suggests a successional process that is determined by the close relationship between sea-level and plant community dynamics. The salt tolerant Chenopodiaceae, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE-stadials, causing the continued recruitment of pioneer species, which are the only ones tolerating rapid rates of disturbance. Once sea-level rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species. These results add to the scarce knowledge on the dynamics of tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes following Antarctic climate variability.

  3. Impacts of climate change on prioritizing conservation areas of hydrological ecosystem services

    NASA Astrophysics Data System (ADS)

    Lien, Wan Yu; Lin, Yu Pin

    2015-04-01

    Ecosystem services (ESs) including hydrological services play important roles in our daily life and provide a lot of benefits for human beings from ecological systems. The systems and their services may be threatened by climate change from global to local scales. We herein developed a systematic approach to assess the impacts of climate change on the hydrological ecosystem services, such as water yield, nutrient (nitrogen and phosphorous) retention, and soil retention in a watershed in Northern Taiwan. We first used an ecosystem service evaluation model, InVEST, to estimate the amount and spatial patterns of annual and monthly hydrological ecosystem services under historical weather data, and different climate change scenarios based on five GMSs. The monthly and annual spatiotemporal variations of the ESs were analyzed in this study. Finally, the multiple estimated ESs were considered as the protection conservation targets and regarded as the input data of the systematic conservation planning software, Zonation, to systematically prioritize reserve areas of the ESs under the climate change scenarios. The ES estimation results indicated that the increasing rainfall in wet season leads to the higher water yield and results in the higher sediment and nutrient export indirectly. The Zonation successfully fielded conservation priorities of the ESs. The conservation priorities of the ESs significantly varied spatially and monthly under the climate change scenarios. The ESs results also indicated that the areas where ESs values and conservation priorities with low resilience under climate change should be considered as high priority protected area to ensure the hydrological services in future. Our proposed approach is a novel systematic approach which can be applied to assess impacts of climate change on spatiotemporal variations of ESs as well as prioritize protected area of the ESs under various climate change scenarios. Keyword: climate change, ecosystem service

  4. Impacts of climate change on nutrient cycling in semi-arid and arid ecosystems

    SciTech Connect

    Belnap, J.

    1995-09-01

    Effective precipitation is a major factor in determining nutrient pathways in different ecosystems. Soil flora and fauna play a critical role in nutrient cycles of all ecosystems. Temperature, timing, and amounts of precipitation affect population composition, activity levels, biomass, and recovery rates from disturbance. Changes in these variables can result in very different inputs and outputs for different nutrients. As a result, areas with less effective precipitation have very different nutrient cycles than more mesic zones. Climate change, therefore, can profoundly affect the nutrient cycles of ecosystems. Nitrogen cycles may be especially sensitive to changes in temperature and to timing and amounts of precipitation. Rainfall contains varying amounts of nitrogen compounds. Changes in amounts of rainfall will change amounts of nitrogen available to these systems. Because rainfall is limited in semi-arid and regions, these systems tend to be more dependent on microbial populations for nitrogen input. Consequently, understanding the effects of climate change on these organisms is critical in understanding the overall effect on ecosystems.

  5. Global change impacts on river ecosystems: A high-resolution watershed study of Ebro river metabolism.

    PubMed

    Val, Jonatan; Chinarro, David; Pino, María Rosa; Navarro, Enrique

    2016-11-01

    Global change is transforming freshwater ecosystems, mainly through changes in basin flow dynamics. This study assessed how the combination of climate change and human management of river flow impacts metabolism of the Ebro River (the largest river basin in Spain, 86,100km(2)), assessed as gross primary production-GPP-and ecosystem respiration-ER. In order to investigate the influence of global change on freshwater ecosystems, an analysis of trends and frequencies from 25 sampling sites of the Ebro river basin was conducted. For this purpose, we examined the effect of anthropogenic flow control on river metabolism with a Granger causality study; simultaneously, took into account the effects of climate change, a period of extraordinary drought (largest in past 140years). We identified periods of sudden flow changes resulting from both human management and global climate effects. From 1998 to 2012, the Ebro River basin was trending toward a more autotrophic condition indicated by P/R ratio. Particularly, the results show that floods that occurred after long periods of low flows had a dramatic impact on the respiration (i.e., mineralization) capacity of the river. This approach allowed for a detailed characterization of the relationships between river metabolism and drought impacts at the watershed level. These findings may allow for a better understanding of the ecological impacts provoked by flow management, thus contributing to maintain the health of freshwater communities and ecosystem services that rely on their integrity. PMID:27392332

  6. CO2 and fire influence tropical ecosystem stability in response to climate change

    PubMed Central

    Shanahan, Timothy M.; Hughen, Konrad A.; McKay, Nicholas P.; Overpeck, Jonathan T.; Scholz, Christopher A.; Gosling, William D.; Miller, Charlotte S.; Peck, John A.; King, John W.; Heil, Clifford W.

    2016-01-01

    Interactions between climate, fire and CO2 are believed to play a crucial role in controlling the distributions of tropical woodlands and savannas, but our understanding of these processes is limited by the paucity of data from undisturbed tropical ecosystems. Here we use a 28,000-year integrated record of vegetation, climate and fire from West Africa to examine the role of these interactions on tropical ecosystem stability. We find that increased aridity between 28–15 kyr B.P. led to the widespread expansion of tropical grasslands, but that frequent fires and low CO2 played a crucial role in stabilizing these ecosystems, even as humidity changed. This resulted in an unstable ecosystem state, which transitioned abruptly from grassland to woodlands as gradual changes in CO2 and fire shifted the balance in favor of woody plants. Since then, high atmospheric CO2 has stabilized tropical forests by promoting woody plant growth, despite increased aridity. Our results indicate that the interactions between climate, CO2 and fire can make tropical ecosystems more resilient to change, but that these systems are dynamically unstable and potentially susceptible to abrupt shifts between woodland and grassland dominated states in the future. PMID:27427431

  7. CO2 and fire influence tropical ecosystem stability in response to climate change.

    PubMed

    Shanahan, Timothy M; Hughen, Konrad A; McKay, Nicholas P; Overpeck, Jonathan T; Scholz, Christopher A; Gosling, William D; Miller, Charlotte S; Peck, John A; King, John W; Heil, Clifford W

    2016-01-01

    Interactions between climate, fire and CO2 are believed to play a crucial role in controlling the distributions of tropical woodlands and savannas, but our understanding of these processes is limited by the paucity of data from undisturbed tropical ecosystems. Here we use a 28,000-year integrated record of vegetation, climate and fire from West Africa to examine the role of these interactions on tropical ecosystem stability. We find that increased aridity between 28-15 kyr B.P. led to the widespread expansion of tropical grasslands, but that frequent fires and low CO2 played a crucial role in stabilizing these ecosystems, even as humidity changed. This resulted in an unstable ecosystem state, which transitioned abruptly from grassland to woodlands as gradual changes in CO2 and fire shifted the balance in favor of woody plants. Since then, high atmospheric CO2 has stabilized tropical forests by promoting woody plant growth, despite increased aridity. Our results indicate that the interactions between climate, CO2 and fire can make tropical ecosystems more resilient to change, but that these systems are dynamically unstable and potentially susceptible to abrupt shifts between woodland and grassland dominated states in the future. PMID:27427431

  8. Ecosystem heterogeneity determines the ecological resilience of the Amazon to climate change.

    PubMed

    Levine, Naomi M; Zhang, Ke; Longo, Marcos; Baccini, Alessandro; Phillips, Oliver L; Lewis, Simon L; Alvarez-Dávila, Esteban; Segalin de Andrade, Ana Cristina; Brienen, Roel J W; Erwin, Terry L; Feldpausch, Ted R; Monteagudo Mendoza, Abel Lorenzo; Nuñez Vargas, Percy; Prieto, Adriana; Silva-Espejo, Javier Eduardo; Malhi, Yadvinder; Moorcroft, Paul R

    2016-01-19

    Amazon forests, which store ∼ 50% of tropical forest carbon and play a vital role in global water, energy, and carbon cycling, are predicted to experience both longer and more intense dry seasons by the end of the 21st century. However, the climate sensitivity of this ecosystem remains uncertain: several studies have predicted large-scale die-back of the Amazon, whereas several more recent studies predict that the biome will remain largely intact. Combining remote-sensing and ground-based observations with a size- and age-structured terrestrial ecosystem model, we explore the sensitivity and ecological resilience of these forests to changes in climate. We demonstrate that water stress operating at the scale of individual plants, combined with spatial variation in soil texture, explains observed patterns of variation in ecosystem biomass, composition, and dynamics across the region, and strongly influences the ecosystem's resilience to changes in dry season length. Specifically, our analysis suggests that in contrast to existing predictions of either stability or catastrophic biomass loss, the Amazon forest's response to a drying regional climate is likely to be an immediate, graded, heterogeneous transition from high-biomass moist forests to transitional dry forests and woody savannah-like states. Fire, logging, and other anthropogenic disturbances may, however, exacerbate these climate change-induced ecosystem transitions. PMID:26711984

  9. Macroecological scale effects of biodiversity on ecosystem functions under environmental change.

    PubMed

    Burley, Hugh M; Mokany, Karel; Ferrier, Simon; Laffan, Shawn W; Williams, Kristen J; Harwood, Tom D

    2016-04-01

    Conserving different spatial and temporal dimensions of biological diversity is considered necessary for maintaining ecosystem functions under predicted global change scenarios. Recent work has shifted the focus from spatially local (α-diversity) to macroecological scales (β- and γ-diversity), emphasizing links between macroecological biodiversity and ecosystem functions (MB-EF relationships). However, before the outcomes of MB-EF analyses can be useful to real-world decisions, empirical modeling needs to be developed for natural ecosystems, incorporating a broader range of data inputs, environmental change scenarios, underlying mechanisms, and predictions. We outline the key conceptual and technical challenges currently faced in developing such models and in testing and calibrating the relationships assumed in these models using data from real ecosystems. These challenges are explored in relation to two potential MB-EF mechanisms: "macroecological complementarity" and "spatiotemporal compensation." Several regions have been sufficiently well studied over space and time to robustly test these mechanisms by combining cutting-edge spatiotemporal methods with remotely sensed data, including plant community data sets in Australia, Europe, and North America. Assessing empirical MB-EF relationships at broad spatiotemporal scales will be crucial in ensuring these macroecological processes can be adequately considered in the management of biodiversity and ecosystem functions under global change. PMID:27066246

  10. Object-based rapid change detection for disaster management

    NASA Astrophysics Data System (ADS)

    Thunig, Holger; Michel, Ulrich; Ehlers, Manfred; Reinartz, Peter

    2011-11-01

    Rapid change detection is used in cases of natural hazards and disasters. This analysis lead to quick information about areas of damage. In certain cases the lack of information after catastrophe events is obstructing supporting measures within disaster management. Earthquakes, tsunamis, civil war, volcanic eruption, droughts and floods have much in common: people are directly affected, landscapes and buildings are destroyed. In every case geospatial data is necessary to gain knowledge as basement for decision support. Where to go first? Which infrastructure is usable? How much area is affected? These are essential questions which need to be answered before appropriate, eligible help can be established. This study presents an innovative strategy to retrieve post event information by use of an object-based change detection approach. Within a transferable framework, the developed algorithms can be implemented for a set of remote sensing data among different investigation areas. Several case studies are the base for the retrieved results. Within a coarse dividing into statistical parts and the segmentation in meaningful objects, the framework is able to deal with different types of change. By means of an elaborated normalized temporal change index (NTCI) panchromatic datasets are used to extract areas which are destroyed, areas which were not affected and in addition areas which are developing new for cases where rebuilding has already started. The results of the study are also feasible for monitoring urban growth.

  11. Selected physical, biological and biogeochemical implications of a rapidly changing Arctic Marginal Ice Zone

    NASA Astrophysics Data System (ADS)

    Barber, David G.; Hop, Haakon; Mundy, Christopher J.; Else, Brent; Dmitrenko, Igor A.; Tremblay, Jean-Eric; Ehn, Jens K.; Assmy, Philipp; Daase, Malin; Candlish, Lauren M.; Rysgaard, Søren

    2015-12-01

    The Marginal Ice Zone (MIZ) of the Arctic Ocean is changing rapidly due to a warming Arctic climate with commensurate reductions in sea ice extent and thickness. This Pan-Arctic review summarizes the main changes in the Arctic ocean-sea ice-atmosphere (OSA) interface, with implications for primary- and secondary producers in the ice and the underlying water column. Changes in the Arctic MIZ were interpreted for the period 1979-2010, based on best-fit regressions for each month. Trends of increasingly open water were statistically significant for each month, with quadratic fit for August-November, illustrating particularly strong seasonal feedbacks in sea-ice formation and decay. Geographic interpretations of physical and biological changes were based on comparison of regions with significant changes in sea ice: (1) The Pacific Sector of the Arctic Ocean including the Canada Basin and the Beaufort, Chukchi and East Siberian seas; (2) The Canadian Arctic Archipelago; (3) Baffin Bay and Hudson Bay; and (4) the Barents and Kara seas. Changes in ice conditions in the Barents sea/Kara sea region appear to be primarily forced by ocean heat fluxes during winter, whereas changes in the other sectors appear to be more summer-autumn related and primarily atmospherically forced. Effects of seasonal and regional changes in OSA-system with regard to increased open water were summarized for photosynthetically available radiation, nutrient delivery to the euphotic zone, primary production of ice algae and phytoplankton, ice-associated fauna and zooplankton, and gas exchange of CO2. Changes in the physical factors varied amongst regions, and showed direct effects on organisms linked to sea ice. Zooplankton species appear to be more flexible and likely able to adapt to variability in the onset of primary production. The major changes identified for the ice-associated ecosystem are with regard to production timing and abundance or biomass of ice flora and fauna, which are related to

  12. Global environmental change: What are the impacts of climate change and land cover change on different ecosystems?

    NASA Astrophysics Data System (ADS)

    Southworth, Jane

    This research incorporates the technologies of climate modeling, vegetation modeling, remote sensing and Geographic Information Systems analyses to monitor changes in land cover across the Midwestern United States, Western Honduras, and the Yucatan Peninsula. These changes in land cover are due to human impacts such as deforestation and reforestation (Honduras and Mexico), and also are due to climate change impacts as modeled for 2050 (Midwestern United States). The overall objective of this research is to understand more fully the processes and potential impacts of land cover change and future climate change on both managed and natural terrestrial ecosystems. The potential impacts of future climate change, for the 2050s, across the Midwestern United States, are for decreased maize yields across the southern portions of the study area, and increased yields across the northern areas. The high summer maximum temperatures inhibit maize growth above temperatures of 35°C, which become more frequent across southern areas of the study region. In addition increases in climate variability results in decreased maize yields and CO2 fertilization for maize, a C4 crop, is limited. For forested regions potential climate change under a doubled CO2 climate results in an overall shift in forest composition from a transitional oak-hickory and beech-maple composition to a predominantly oak-hickory forest. In addition northern conifers and northern deciduous species were almost completely extirpated from the study region. Land cover, specifically forest cover, changes across the study region of western Honduras and eastern Guatemala, show an overall trend of deforestation between 1987 and 1996. However, at the smaller study area scale of La Campa, reforestation is the dominant trend. These differences relate to a ban on logging within the community, land tenure and agricultural intensification processes currently occurring in the region. Research on changes in land cover using

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

    PubMed

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

    2012-08-01

    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

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

    USGS Publications Warehouse

    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

  15. The Role of Plants as Ecosystem Engineers in Resilience to Climate Change

    NASA Astrophysics Data System (ADS)

    Shachak, Moshe; Arbel, Shmuel; Boeken, Bertrand; Segoli, Moran; Ungar, Eugene; Zaady, Eli

    2010-05-01

    In drylands landscape structure is controlled by two ecosystem engineers, soil microphytes and shrubs. Soil microphytes adhere the soil particles by secreting polysaccharides, thus forming biogenic soil crusts. Shrubs engineer the environment above and below ground. Above ground they can form soil mounds and below ground modulate the soil properties by their roots. The two engineering modes create shrub patches in the landscape. The two phase mosaic formed by the engineers creates a source-sink system where the crust is a source of soil, water, organic matter and nutrients while the shrub patch is the sink. Most of the productivity and diversity of the system is concentrated in the sink patches. Climate change such as the increase in frequency and severity of droughts may affect the function of the two phase mosaic by causing shrub dieback. This can transform a shrub land into crust land by increasing leakage of resources and decreasing productivity and diversity (desertification). Based on our long term research at LTER sites in the Northern Negev, Israel, we present two models depicting how climate change can cause state changes from shrub land to crust land and how the mode of shrub engineering can prevent this transition. Our main proposition is that the resilience of a two phase mosaic to drought depends on whether the engineering is by mound formation or by subsurface soil modulation. When the engineering mode is mound formation, shrubs dying due to drought expose the underlying mound to erosion by rainfall and runoff. The eroded patch is then colonized by microphytes which form soil crusts. This process takes between five to ten years. To rebuild the soil mound by a shrub takes hundreds of years. Therefore, once the soil mound is eroded the area will then be transformed from shrub land to crust land and the recovery time is long. When the engineering is through the roots the system is more resilient to drought. Even if the canopy dies back the shrub patch

  16. Climate change and river ecosystems: protection and adaptation options.

    PubMed

    Palmer, Margaret A; Lettenmaier, Dennis P; Poff, N Leroy; Postel, Sandra L; Richter, Brian; Warner, Richard

    2009-12-01

    Rivers provide a special suite of goods and services valued highly by the public that are inextricably linked to their flow dynamics and the interaction of flow with the landscape. Yet most rivers are within watersheds that are stressed to some extent by human activities including development, dams, or extractive uses. Climate change will add to and magnify risks that are already present through its potential to alter rainfall, temperature, runoff patterns, and to disrupt biological communities and sever ecological linkages. We provide an overview of the predicted impacts based on published studies to date, discuss both reactive and proactive management responses, and outline six categories of management actions that will contribute substantially to the protection of valuable river assets. To be effective, management must be place-based focusing on local watershed scales that are most relevant to management scales. The first priority should be enhancing environmental monitoring of changes and river responses coupled with the development of local scenario-building exercises that take land use and water use into account. Protection of a greater number of rivers and riparian corridors is essential, as is conjunctive groundwater/surface water management. This will require collaborations among multiple partners in the respective river basins and wise land use planning to minimize additional development in watersheds with valued rivers. Ensuring environmental flows by purchasing or leasing water rights and/or altering reservoir release patterns will be needed for many rivers. Implementing restoration projects proactively can be used to protect existing resources so that expensive reactive restoration to repair damage associated with a changing climate is minimized. Special attention should be given to diversifying and replicating habitats of special importance and to monitoring populations at high risk or of special value so that management interventions can occur if the

  17. Climate Change and River Ecosystems: Protection and Adaptation Options

    NASA Astrophysics Data System (ADS)

    Palmer, Margaret A.; Lettenmaier, Dennis P.; Poff, N. Leroy; Postel, Sandra L.; Richter, Brian; Warner, Richard

    2009-12-01

    Rivers provide a special suite of goods and services valued highly by the public that are inextricably linked to their flow dynamics and the interaction of flow with the landscape. Yet most rivers are within watersheds that are stressed to some extent by human activities including development, dams, or extractive uses. Climate change will add to and magnify risks that are already present through its potential to alter rainfall, temperature, runoff patterns, and to disrupt biological communities and sever ecological linkages. We provide an overview of the predicted impacts based on published studies to date, discuss both reactive and proactive management responses, and outline six categories of management actions that will contribute substantially to the protection of valuable river assets. To be effective, management must be place-based focusing on local watershed scales that are most relevant to management scales. The first priority should be enhancing environmental monitoring of changes and river responses coupled with the development of local scenario-building exercises that take land use and water use into account. Protection of a greater number of rivers and riparian corridors is essential, as is conjunctive groundwater/surface water management. This will require collaborations among multiple partners in the respective river basins and wise land use planning to minimize additional development in watersheds with valued rivers. Ensuring environmental flows by purchasing or leasing water rights and/or altering reservoir release patterns will be needed for many rivers. Implementing restoration projects proactively can be used to protect existing resources so that expensive reactive restoration to repair damage associated with a changing climate is minimized. Special attention should be given to diversifying and replicating habitats of special importance and to monitoring populations at high risk or of special value so that management interventions can occur if the

  18. [Application of ecosystem service value in land use change research: Bottlenecks and prospects].

    PubMed

    Zhang, Zhou; Wu, Ci-Fang; Tan, Rong

    2013-02-01

    In recent years, the application of ecosystem service value in land use change research is a hot topic in many famous international journals. However, policy makers are seldom taking into account the achievements of the related studies in practice. This paper summarized the three main bottlenecks in applying ecosystem service value in land management practices, i. e., the difficulty in measuring the service values, the complexity of driving factors, and the bias of evaluation criteria. Some solutions on the bottlenecks were provided, and the future research directions in China were prospected. It was suggested that in the studies of land use change based on ecosystem service value, it would be more appropriate to adopt comparative analysis method in small scale case studies, especially focusing on the natural ecological resources and the excessive loss of their values. PMID:23705405

  19. Urban ecosystem modeling and global change: potential for rational urban management and emissions mitigation.

    PubMed

    Chen, Shaoqing; Chen, Bin; Fath, Brian D

    2014-07-01

    Urbanization is a strong and extensive driver that causes environmental pollution and climate change from local to global scale. Modeling cities as ecosystems has been initiated by a wide range of scientists as a key to addressing challenging problems concomitant with urbanization. In this paper, 'urban ecosystem modeling (UEM)' is defined in an inter-disciplinary context to acquire a broad perception of urban ecological properties and their interactions with global change. Furthermore, state-of-the-art models of urban ecosystems are reviewed, categorized as top-down models (including materials/energy-oriented models and structure-oriented models), bottom-up models (including land use-oriented models and infrastructure-oriented models), or hybrid models thereof. Based on the review of UEM studies, a future framework for explicit UEM is proposed based the integration of UEM approaches of different scales, guiding more rational urban management and efficient emissions mitigation. PMID:24747346

  20. Non-equilbrium dynamics of ecosystem processes in a changing world

    NASA Astrophysics Data System (ADS)

    Reid, Joseph Pignatello

    The relatively mild and stable climate of the last 10,000 years betrays a history of environmental variability and rapid changes. Humans have recently accelerated global environmental change, ushering in the Anthropocene. Meeting accelerating demands for food, energy, and goods and services has accelerated species extinctions, shows of reactive nitrogen and phosphorus, and warming of the atmosphere. I address the over- arching question of how ecosystems will respond to changing and variable environments through several focused studies. Each study examines an ecosystem response to ex- pected environmental changes in the future. To address how the changing environment affects the sizes and turnover rates of slowly and quickly cycling soil carbon pools, I analyzed the responses of grassland soils to simulated species diversity loss, increased deposition of nitrogen and increased atmospheric CO2. I used a soil respiration experiment to fit models of soil carbon pool turnover to respired carbon dioxide. Species diversity, nitrogen deposition and atmospheric CO2 had no effect on the total soil carbon after 8 years of treatments. Although total soil carbon did not change, the rates of cycling in the fast and slow pools changed in response to elevated CO2 and diversity loss treatments. Nitrogen treatments increased the size of the slowly cycling carbon pool. Precipitation variability has increased around most of the world since the industrial revolution. I used plant mesocosms in a greenhouse experiment to manipulate rainfall variability and mycorrhizal associations. I hypothesized that 1) rewetting events re- sult in higher nitrogen uxes from dry soils than moist soils, 2) a repeated pattern of events caused by low-frequency simulated rainfall results in higher nitrogen uxes and 3) the better ability of ectomycorrhizal fungi relative to arbuscular mycorrhizal fungi to decompose and assimilate organic nitrogen reduces leaching losses of nitrogen caused by both rewetting

  1. Non-equilbrium dynamics of ecosystem processes in a changing world

    NASA Astrophysics Data System (ADS)

    Reid, Joseph Pignatello

    The relatively mild and stable climate of the last 10,000 years betrays a history of environmental variability and rapid changes. Humans have recently accelerated global environmental change, ushering in the Anthropocene. Meeting accelerating demands for food, energy, and goods and services has accelerated species extinctions, shows of reactive nitrogen and phosphorus, and warming of the atmosphere. I address the over- arching question of how ecosystems will respond to changing and variable environments through several focused studies. Each study examines an ecosystem response to ex- pected environmental changes in the future. To address how the changing environment affects the sizes and turnover rates of slowly and quickly cycling soil carbon pools, I analyzed the responses of grassland soils to simulated species diversity loss, increased deposition of nitrogen and increased atmospheric CO2. I used a soil respiration experiment to fit models of soil carbon pool turnover to respired carbon dioxide. Species diversity, nitrogen deposition and atmospheric CO2 had no effect on the total soil carbon after 8 years of treatments. Although total soil carbon did not change, the rates of cycling in the fast and slow pools changed in response to elevated CO2 and diversity loss treatments. Nitrogen treatments increased the size of the slowly cycling carbon pool. Precipitation variability has increased around most of the world since the industrial revolution. I used plant mesocosms in a greenhouse experiment to manipulate rainfall variability and mycorrhizal associations. I hypothesized that 1) rewetting events re- sult in higher nitrogen uxes from dry soils than moist soils, 2) a repeated pattern of events caused by low-frequency simulated rainfall results in higher nitrogen uxes and 3) the better ability of ectomycorrhizal fungi relative to arbuscular mycorrhizal fungi to decompose and assimilate organic nitrogen reduces leaching losses of nitrogen caused by both rewetting

  2. Risk and contributing factors of ecosystem shifts over naturally vegetated land under climate change in China

    PubMed Central

    Yin, Yuanyuan; Tang, Qiuhong; Wang, Lixin; Liu, Xingcai

    2016-01-01

    Identifying the areas at risk of ecosystem transformation and the main contributing factors to the risk is essential to assist ecological adaptation to climate change. We assessed the risk of ecosystem shifts in China using the projections of four global gridded vegetation models (GGVMs) and an aggregate metric. The results show that half of naturally vegetated land surface could be under moderate or severe risk at the end of the 21st century under the middle and high emission scenarios. The areas with high risk are the Tibetan Plateau region and an area extended northeastward from the Tibetan Plateau to northeast China. With the three major factors considered, the change in carbon stocks is the main contributing factor to the high risk of ecosystem shifts. The change in carbon fluxes is another important contributing factor under the high emission scenario. The change in water fluxes is a less dominant factor except for the Tibetan Plateau region under the high emission scenario. Although there is considerable uncertainty in the risk assessment, the geographic patterns of the risk are generally consistent across different scenarios. The results could help develop regional strategies for ecosystem conservation to cope with climate change. PMID:26867481

  3. Climate-ecosystem change off southern California: Time-dependent seabird predator-prey numerical responses

    NASA Astrophysics Data System (ADS)

    Sydeman, William J.; Thompson, Sarah Ann; Santora, Jarrod A.; Koslow, J. Anthony; Goericke, Ralf; Ohman, Mark D.

    2015-02-01

    Climate change may increase both stratification and upwelling in marine ecosystems, but these processes may affect productivity in opposing or complementary ways. For the Southern California region of the California Current Ecosystem (CCE), we hypothesized that changes in stratification and upwelling have affected marine bird populations indirectly through changes in prey availability. To test this hypothesis, we derived trends and associations between stratification and upwelling, the relative abundance of potential prey including krill and forage fish, and seabirds based on the long-term, multi-disciplinary CalCOFI/CCE-LTER program. Over the period 1987 through 2011, spring and summer seabird density (all species combined) declined by ~2% per year, mostly in the northern sector of the study region. Krill showed variable trends with two species increasing and one deceasing, resulting in community reorganization. Nearshore forage fish, dominated by northern anchovy (Engraulis mordax) as well as offshore mesopelagic species, show declines in relative abundance over this period. The unidirectional decline in springtime seabird density is largely explained by declining nearshore fish abundance in the previous season (winter). Interannual variability in seabird density, especially in the 2000s, is explained by variability in krill abundance. Changes in the numerical responses of seabirds to prey abundance correspond to a putative ecosystem shift in 1998-1999 and support aspects of optimal foraging (diet) theory. Predator-prey interactions and numerical responses clearly explain aspects of the upper trophic level patterns of change in the pelagic ecosystem off southern California.

  4. Risk and contributing factors of ecosystem shifts over naturally vegetated land under climate change in China.

    PubMed

    Yin, Yuanyuan; Tang, Qiuhong; Wang, Lixin; Liu, Xingcai

    2016-01-01

    Identifying the areas at risk of ecosystem transformation and the main contributing factors to the risk is essential to assist ecological adaptation to climate change. We assessed the risk of ecosystem shifts in China using the projections of four global gridded vegetation models (GGVMs) and an aggregate metric. The results show that half of naturally vegetated land surface could be under moderate or severe risk at the end of the 21(st) century under the middle and high emission scenarios. The areas with high risk are the Tibetan Plateau region and an area extended northeastward from the Tibetan Plateau to northeast China. With the three major factors considered, the change in carbon stocks is the main contributing factor to the high risk of ecosystem shifts. The change in carbon fluxes is another important contributing factor under the high emission scenario. The change in water fluxes is a less dominant factor except for the Tibetan Plateau region under the high emission scenario. Although there is considerable uncertainty in the risk assessment, the geographic patterns of the risk are generally consistent across different scenarios. The results could help develop regional strategies for ecosystem conservation to cope with climate change. PMID:26867481

  5. Lake Michigan offshore ecosystem structure and food web changes from 1987 to 2008

    USGS Publications Warehouse

    Rogers, Mark W.; Bunnell, David B.; Madenjian, Charles P.; Warner, David M.

    2014-01-01

    Ecosystems undergo dynamic changes owing to species invasions, fisheries management decisions, landscape modifications, and nutrient inputs. At Lake Michigan, new invaders (e.g., dreissenid mussels (Dreissena spp.), spiny water flea (Bythotrephes longimanus), round goby (Neogobius melanostomus)) have proliferated and altered energy transfer pathways, while nutrient concentrations and stocking rates to support fisheries have changed. We developed an ecosystem model to describe food web structure in 1987 and ran simulations through 2008 to evaluate changes in biomass of functional groups, predator consumption, and effects of recently invading species. Keystone functional groups from 1987 were identified as Mysis, burbot (Lota lota), phytoplankton, alewife (Alosa pseudoharengus), nonpredatory cladocerans, and Chinook salmon (Oncorhynchus tshawytscha). Simulations predicted biomass reductions across all trophic levels and predicted biomasses fit observed trends for most functional groups. The effects of invasive species (e.g., dreissenid grazing) increased across simulation years, but were difficult to disentangle from other changes (e.g., declining offshore nutrient concentrations). In total, our model effectively represented recent changes to the Lake Michigan ecosystem and provides an ecosystem-based tool for exploring future resource management scenarios.

  6. Public health impacts of ecosystem change in the Brazilian Amazon

    PubMed Central

    Bauch, Simone C.; Birkenbach, Anna M.; Pattanayak, Subhrendu K.; Sills, Erin O.

    2015-01-01

    The claim that nature delivers health benefits rests on a thin empirical evidence base. Even less evidence exists on how specific conservation policies affect multiple health outcomes. We address these gaps in knowledge by combining municipal-level panel data on diseases, public health services, climatic factors, demographics, conservation policies, and other drivers of land-use change in the Brazilian Amazon. To fully exploit this dataset, we estimate random-effects and quantile regression models of disease incidence. We find that malaria, acute respiratory infection (ARI), and diarrhea incidence are significantly and negatively correlated with the area under strict environmental protection. Results vary by disease for other types of protected areas (PAs), roads, and mining. The relationships between diseases and land-use change drivers also vary by quantile of the disease distribution. Conservation scenarios based on estimated regression results suggest that malaria, ARI, and diarrhea incidence would be reduced by expanding strict PAs, and malaria could be further reduced by restricting roads and mining. Although these relationships are complex, we conclude that interventions to preserve natural capital can deliver cobenefits by also increasing human (health) capital. PMID:26082548

  7. Public health impacts of ecosystem change in the Brazilian Amazon.

    PubMed

    Bauch, Simone C; Birkenbach, Anna M; Pattanayak, Subhrendu K; Sills, Erin O

    2015-06-16

    The claim that nature delivers health benefits rests on a thin empirical evidence base. Even less evidence exists on how specific conservation policies affect multiple health outcomes. We address these gaps in knowledge by combining municipal-level panel data on diseases, public health services, climatic factors, demographics, conservation policies, and other drivers of land-use change in the Brazilian Amazon. To fully exploit this dataset, we estimate random-effects and quantile regression models of disease incidence. We find that malaria, acute respiratory infection (ARI), and diarrhea incidence are significantly and negatively correlated with the area under strict environmental protection. Results vary by disease for other types of protected areas (PAs), roads, and mining. The relationships between diseases and land-use change drivers also vary by quantile of the disease distribution. Conservation scenarios based on estimated regression results suggest that malaria, ARI, and diarrhea incidence would be reduced by expanding strict PAs, and malaria could be further reduced by restricting roads and mining. Although these relationships are complex, we conclude that interventions to preserve natural capital can deliver cobenefits by also increasing human (health) capital. PMID:26082548

  8. Caribbean mesophotic coral ecosystems are unlikely climate change refugia.

    PubMed

    Smith, Tyler B; Gyory, Joanna; Brandt, Marilyn E; Miller, William J; Jossart, Jonathan; Nemeth, Richard S

    2016-08-01

    Deeper coral reefs experience reduced temperatures and light and are often shielded from localized anthropogenic stressors such as pollution and fishing. The deep reef refugia hypothesis posits that light-dependent stony coral species at deeper depths are buffered from thermal stress and will avoid bleaching-related mass mortalities caused by increasing sea surface temperatures under climate change. This hypothesis has not been tested because data collection on deeper coral reefs is difficult. Here we show that deeper (mesophotic) reefs, 30-75 m depth, in the Caribbean are not refugia because they have lower bleaching threshold temperatures than shallow reefs. Over two thermal stress events, mesophotic reef bleaching was driven by a bleaching threshold that declines 0.26 °C every +10 m depth. Thus, the main premise of the deep reef refugia hypothesis that cooler environments are protective is incorrect; any increase in temperatures above the local mean warmest conditions can lead to thermal stress and bleaching. Thus, relatively cooler temperatures can no longer be considered a de facto refugium for corals and it is likely that many deeper coral reefs are as vulnerable to climate change as shallow water reefs. PMID:26648385

  9. EFFECTS OF CLIMATE VARIABILITY AND CHANGE ON STREAM ECOSYSTEMS UNDER ALTERNATIVE FUTURE GROWTH SCENARIOS IN THE WASHINGTON METROPOLITAN AREA

    EPA Science Inventory

    The goal of this study is to advance the understanding of how the effects of climate variability and change on stream ecosystems depend on land-use choices in surrounding areas. Global changes affect aquatic ecosystems through changes in water quality, hydrology, temperature, sea...

  10. A monitoring protocol for the ecohydrological effects of land use changes in tropical mountain ecosystems

    NASA Astrophysics Data System (ADS)

    Flórez, C. P.; León, J. D.; Villegas, J. C.; Betancur, T.; Suescún, D.; García-Leoz, V.; Cardona, A. I.; Martin, Á. M.

    2014-12-01

    In tropical mountain regions, the societal demands for ecosystem services has led to pressure over ecosystems that, in ocassions, may threaten the capacity of ecosystems to provide services. More specifically, global-change processes such as land use change and climate dynamics may lead to uncertainties about the stability of ecosystem functions on which services rely on. Of particular interest are the effects of land cover changes on the hydrological dynamics of the soil, that support multiple regulation and provision services, critical for a large portion of the population settled in mountain regions of the world. In this work, we present a protocol for the combined monitoring of ecohydrological, biogeochemical and sediment dynamics in a group of instrumented plots representing a typical gradient of human intervention in a tropical mountain ecosystem. Land cover categories include: a mature forest, secondary forest, early successional stage, recently abandoned agricultural field, a cattle pasture, permanent cropland, a high rotation cropland. On each plot, water fluxes from the top of the canopy to 1.5 m below soil surface are measured using a diverse array of instruments, along with measurements of sediment load in runoff waters and nutrient loads for all hydrologic compartments (measurements include Ca, Mg, K, P, NH4, NO3, Mn, Fe). Our preliminary results indicate that although rainfall does not vary significantly among plots, runoff generation does, with higher values ocurring in the pasture. Conversely, infiltration rates are highest in both types of forests, particularly for shallower layers of the soil. Chemical analysis indicate higher nutrient loads in runoff generating from croplands, highlighting the potential loss of soil fertility and potentially leading to eutrophication in water bodies downstream. After completion, our results will provide land managers tools to assess larger-scale effects of land use changes on the capacity of ecosystems to provide

  11. Soil hydrological properties regulate grassland ecosystem responses to multifactor global change: A modeling analysis

    NASA Astrophysics Data System (ADS)

    Weng, Ensheng; Luo, Yiqi

    2008-09-01

    We conducted a modeling study to evaluate how soil hydrological properties regulate water and carbon dynamics of grassland ecosystems in response to multifactor global change. We first calibrated a process-based terrestrial ecosystem (TECO) model against data from two experiments with warming and clipping or doubled precipitation in Great Plains. The calibrated model was used to simulate responses of soil moisture, evaporation, transpiration, runoff, net primary production (NPP), ecosystem respiration (Rh), and net ecosystem production (NEP) to changes in precipitation amounts and intensity, increased temperature, and elevated atmospheric [CO2] along a soil texture gradient (sand, sandy loam, loam, silt loam, and clay loam). Soil available water capacity (AWC), which is the difference between field capacity and wilting point, was used as the index to represent soil hydrological properties of the five soil texture types. Simulation results showed that soil AWC altered partitioning of precipitation among runoff, evaporation, and transpiration, and consequently regulated ecosystem responses to global environmental changes. The fractions of precipitation that were used for evaporation and transpiration increased with soil AWC but decreased for runoff. High AWC could greatly buffer water stress during long drought periods, particularly after a large rainfall event. NPP, Rh, and NEP usually increased with AWC under ambient and 50% increased precipitation scenarios. With the halved precipitation amount, NPP, Rh, and NEP only increased from 7% to 7.5% of AWC followed by declines. Warming and CO2 effects on soil moisture, evapotranspiration, and runoff were magnified by soil AWC. Regulatory patterns of AWC on responses of NPP, Rh, and NEP to warming were complex. In general, CO2 effects on NPP, Rh, and NEP increased with soil AWC. Our results indicate that variations in soil texture may be one of the major causes underlying variable responses of ecosystems to global changes

  12. Diverging Plant and Ecosystem Strategies in Response to Climate Change in the High Arctic

    NASA Astrophysics Data System (ADS)

    Maseyk, K. S.; Welker, J. M.; Czimczik, C. I.; Lupascu, M.; Lett, C.; Seibt, U. H.

    2014-12-01

    Increasing summer precipitation means Arctic growing seasons are becoming wetter as well as warmer, but the effect of these coupled changes on tundra ecosystem functioning remains largely unknown. We have determined how warmer and wetter summers affect coupled carbon-water cycling in a High Arctic polar semi-desert ecosystem in NW Greenland. Measurements of ecosystem CO2 and water fluxes throughout the growing season and leaf ecophysiological traits (gas exchange, morphology, leaf chemistry) were made at a long-term climate change experiment. After 9 years of exposure to warmer (+ 4°C) and / or wetter (+ 50% precipitation) treatments, we found diverging plant strategies between the responses to warming with or without an increase in summer precipitation. Warming alone resulted in an increase in leaf nitrogen, mesophyll conductance and leaf-mass per area and higher rates of leaf-level photosynthesis, but with warming and wetting combined leaf traits remain largely unchanged. However, total leaf area increased with warming plus wetting but was unchanged with warming alone. The combined effect of these leaf trait and canopy adjustments is a decrease in ecosystem water-use efficiency (the ratio of net productivity to evapotranspiration) with warming only, but a substantial increase with combined warming and wetting. We conclude that increasing summer precipitation will alter tundra ecohydrological responses to warming; that leaf-level changes in ecophysiological traits have an upward cascading consequence for ecosystem and land surface-climate interactions; and the current relative resistance of High Arctic ecosystems to warming may mask biochemical and carbon cycling changes already underway.

  13. Effects of Past Climate Changes on Ecosystem Biogeochemical Cycles in Rocky Mountain Forests and Lakes

    NASA Astrophysics Data System (ADS)

    Shuman, B.; Mechenich, M. F.; Stefanova, I.; Henderson, A.; Donnelly, J. P.

    2007-12-01

    Ongoing climate trends will likely alter how forest ecosystems produce important goods and services, in part, by changing ecosystem responses to disturbances, such as fires and land-use. Disturbances induce forest succession and thus dramatically change the flow of water and nutrients through a given ecosystem. However, long-term ecosystem responses to disturbance, especially regarding nutrient pools and cycling rates, are poorly documented, and less is known about the effects of century-scale climate trends on these responses especially with respect to moisture. Here, we show biogeochemical responses to repeated (>20) episodes of disturbance and succession in a single ecosystem under a range of climatic conditions over 2000 years. Our lake sediment record shows regular fluctuations in the flux of base cations and other macronutrients from lodgepole pine ( Pinus contorta) forests in northern Colorado following catastrophic stand-replacing fires. Post-fire elemental fluctuations are consistent with ecosystem theory regarding the re-equilibration of biomass and nutrient pools during succession, but show systematic variation that has been previously undocumented. The time span of post-fire re-equilibration correlates positively with measures of fire severity, which is consistent with hypotheses that seed dispersal and soil recovery likely slow re-growth after large or severe fires. Likewise, dry conditions during the Medieval Climatic Anomaly (MCA, 1200-500 yrs BP) altered elemental fluctuations and, thus, generated post-fire pulses of lake eutrophication that were not evident during other periods. The interaction of climate and disturbance, therefore, has important consequences for ecosystem function and services, including the quality of aquatic environments.

  14. Decadal changes in the Canary Current Upwelling Ecosystem

    NASA Astrophysics Data System (ADS)

    Santos, A. M.; Luis, J. M.; Relvas-Almeida, P.

    2013-12-01

    The Canary Current Upwelling System (CCUS) covers the latitudinal range 12-43 degrees N and has some singularities in relation to the other three major Eastern Boundary Upwelling Systems (EBUS), namely a major interruption in the continuity of the system at the Strait of Gibraltar and it is the only one with a sardine species from a different genus (Sardina vs Sardinops). Long-term trends in ocean temperature and coastal upwelling were investigated using the AVHRR Pathfinder SST (sea surface temperature) Version 5.1 dataset, in situ SST from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS), and upwelling indices from the Pacific Fisheries Environmental Laboratory (PFEL). The analysis is applied to the eastern boundary of the North Atlantic, from 10 to 45 degrees N extending until 30 degrees W, focusing mainly in the CCUS because the strong dynamic link between the atmosphere and the ocean makes upwelling regions highly sensitive to global change and ideal to monitor and investigate its effects. The detail in SST variability results in a large extent from the fine analysis and the numerical processing carefully designed to avoid trend bias in the climatological studies. The obtained fields of SST trends show a generalized warming of the entire region. However, alternate patches of significantly different warming rates are observed, ranging from large scale down to mesoscale. Known coastal upwelling features are seen to warm at a lower rate than corresponding offshore waters, pointing to an intensification of the upwelling in the last decades. Wind data are used to attempt to explain the variability of some upwelling structures. Our results evidence the main role that mesoscale processes play in the modulation of the spatial and temporal variability of SST, namely at the decadal scale. This result prevents any global conclusion about the intensification of the upwelling at the scale of the entire CCUS. The bulk of the sardine population is located

  15. Rapid treatment-induced brain changes in pediatric CRPS.

    PubMed

    Erpelding, Nathalie; Simons, Laura; Lebel, Alyssa; Serrano, Paul; Pielech, Melissa; Prabhu, Sanjay; Becerra, Lino; Borsook, David

    2016-03-01

    To date, brain structure and function changes in children with complex regional pain syndrome (CRPS) as a result of disease and treatment remain unknown. Here, we investigated (a) gray matter (GM) differences between patients with CRPS and healthy controls and (b) GM and functional connectivity (FC) changes in patients following intensive interdisciplinary psychophysical pain treatment. Twenty-three patients (13 females, 9 males; average age ± SD = 13.3 ± 2.5 years) and 21 healthy sex- and age-matched controls underwent magnetic resonance imaging. Compared to controls, patients had reduced GM in the primary motor cortex, premotor cortex, supplementary motor area, midcingulate cortex, orbitofrontal cortex, dorsolateral prefrontal cortex (dlPFC), posterior cingulate cortex, precuneus, basal ganglia, thalamus, and hippocampus. Following treatment, patients had increased GM in the dlPFC, thalamus, basal ganglia, amygdala, and hippocampus, and enhanced FC between the dlPFC and the periaqueductal gray, two regions involved in descending pain modulation. Accordingly, our results provide novel evidence for GM abnormalities in sensory, motor, emotional, cognitive, and pain modulatory regions in children with CRPS. Furthermore, this is the first study to demonstrate rapid treatment-induced GM and FC changes in areas implicated in sensation, emotion, cognition, and pain modulation. PMID:25515312

  16. Novel Technologies in Urologic Surgery: a Rapidly Changing Scenario.

    PubMed

    Gandaglia, Giorgio; Schatteman, Peter; De Naeyer, Geert; D'Hondt, Frederiek; Mottrie, Alexandre

    2016-03-01

    The introduction of laparoscopy and robotic surgery revolutionized the surgical management of urologic patients. Nonetheless, we live in an era of rapid changes, and we are probably still in the infancy of technology applied to surgery. When considering currently available technologies, there are several unmet needs to be addressed. These include the application of augmented reality, haptic feedback, tissue recognition, distant remote control, miniaturization of surgical instruments, the learning curve typical of the introduction of novel techniques, and excessive costs. In the next few years, evolution in imaging modalities in pre- and intraoperative surgical planning, as well as the introduction of novel minimally invasive platforms, would in part address these issues, substantially improving surgical outcomes. In addition, validated training programs would allow for the safe implementation of novel techniques in the clinical practice. Finally, a reduction in costs would be necessary to make technology affordable and to optimize healthcare resources. PMID:26874531

  17. Evolutionary period changes in the rapidly oscillating Ap stars

    NASA Technical Reports Server (NTRS)

    Heller, Clayton H.; Kawaler, Steven D.

    1988-01-01

    Preliminary computations of the asymptotic p-mode frequency spacings, and their time derivatives, are presented for a grid of evolutionary models of the rapidly oscillating Ap ('roAp') stars. It is shown how the frequency spacings depend on stellar mass, metallicity, and evolutionary stage. The frequency spacings observed in two of the roAp stars indicate that they either are main-sequence objects or have evolved off of the main sequence, depending on how the pulsation spectrum is interpreted. A way to remove this ambiguity is suggested: secular evolutionary changes in the pulsation frequencies may be measurable if the roAp stars have evolved off of the main sequence. In principle, this determination may be made for the roAp star HR 1217 with existing data.

  18. [Responses of ecosystem services value to land use change in national nature reserves in Xinjiang, China].

    PubMed

    Wang, Yan; Gao, Ji-Xi; Wang, Jin-Sheng; Leng, Ling; Qiu, Jie; Yang, Shan-Shan

    2014-05-01

    With GIS and RS technology, characteristics of land use change and ecosystem services value of different years in six national nature reserves in Xinjiang, China were analyzed with remote sensing image of the year 2000-2010. Results showed that the area of water body and grassland decreased while the area of forest, farmland, wetland, unused land and construction land increased in 2000-2010. Variation rate of land use change in 2000-2005 was faster, as 2.4-6.3 times as that in 2005-2010. The total ecosystem services value mostly consisted of that of water body, grassland and forest, accounting for 93% approximately. During the study, the values of all kinds of the ecosystem services increased except for grassland and water body, the total ecosystem services value increased firstly and then decreased, and overall emerged as a reducing trend with the rate of 1.2%. In the process of the development of the west regions, it is necessary to pay more attention to the protection of natural resources and ecosystem restoration, so as to achieve sustainable development of resources, environment and social economy in the western regions. PMID:25129947

  19. Rapid genomic DNA changes in allotetraploid fish hybrids.

    PubMed

    Wang, J; Ye, L H; Liu, Q Z; Peng, L Y; Liu, W; Yi, X G; Wang, Y D; Xiao, J; Xu, K; Hu, F Z; Ren, L; Tao, M; Zhang, C; Liu, Y; Hong, Y H; Liu, S J

    2015-06-01

    Rapid genomic change has been demonstrated in several allopolyploid plant systems; however, few studies focused on animals. We addressed this issue using an allotetraploid lineage (4nAT) of freshwater fish originally derived from the interspecific hybridization of red crucian carp (Carassius auratus red var., ♀, 2n=100) × common carp (Cyprinus carpio L., ♂, 2n=100). We constructed a bacterial artificial chromosome (BAC) library from allotetraploid hybrids in the 20th generation (F20) and sequenced 14 BAC clones representing a total of 592.126 kb, identified 11 functional genes and estimated the guanine-cytosine content (37.10%) and the proportion of repetitive elements (17.46%). The analysis of intron evolution using nine orthologous genes across a number of selected fish species detected a gain of 39 introns and a loss of 30 introns in the 4nAT lineage. A comparative study based on seven functional genes among 4nAT, diploid F1 hybrids (2nF1) (first generation of hybrids) and their original parents revealed that both hybrid types (2nF1 and 4nAT) not only inherited genomic DNA from their parents, but also demonstrated rapid genomic DNA changes (homoeologous recombination, parental DNA fragments loss and formation of novel genes). However, 4nAT presented more genomic variations compared with their parents than 2nF1. Interestingly, novel gene fragments were found for the iqca1 gene in both hybrid types. This study provided a preliminary genomic characterization of allotetraploid F20 hybrids and revealed evolutionary and functional genomic significance of allopolyploid animals. PMID:25669608

  20. Watershed scale impacts of bioenergy, landscape changes, and ecosystem response

    NASA Astrophysics Data System (ADS)

    Chaubey, Indrajeet; Cibin, Raj; Chiang, Li-Chi

    2013-04-01

    In recent years, high US gasoline prices and national security concerns have prompted a renewed interest in alternative fuel sources to meet increasing energy demands, particularly by the transportation sector. Food and animal feed crops, such as corn and soybean, sugarcane, residue from these crops, and cellulosic perennial crops grown specifically to produce bioenergy (e.g. switchgrass, Miscanthus, mixed grasses), and fast growing trees (e.g. hybrid poplar) are expected to provide the majority of the biofeedstock for energy production. One of the grand challenges in supplying large quantities of grain-based and lignocellulosic materials for the production of biofuels is ensuring that they are produced in environmentally sustainable and economically viable manner. Feedstock selection will vary geographically based on regional adaptability, productivity, and reliability. Changes in land use and management practices related to biofeedstock production may have potential impacts on water quantity and quality, sediments, and pesticides and nutrient losses, and these impacts may be exacerbated by climate variability and change. We have made many improvements in the currently available biophysical models (e.g. Soil and Water Assessment Tool or SWAT model) to evaluate sustainability of energy crop production. We have utilized the improved model to evaluate impacts of both annual (e.g. corn) and perennial bioenergy crops (e.g. Miscanthus and switchgrass at) on hydrology and water quality under the following plausible bioenergy crop production scenarios: (1) at highly erodible areas; (2) at agriculturally marginal areas; (3) at pasture areas; (4) crop residue (corn stover) removal; and (5) combinations of above scenarios. Overall results indicated improvement in water quality with introduction of perennial energy crops. Stream flow at the watershed outlet was reduced under energy crop production scenarios and ranged between 0.3% and 5% across scenarios. Erosion and sediment

  1. Supporting Coral Reef Ecosystem Management Decisions Appropriate to Climate Change

    NASA Astrophysics Data System (ADS)

    Hendee, J. C.; Fletcher, P.; Shein, K. A.

    2013-05-01

    There has been a perception that the myriad of environmental information products derived from satellite and other instrumental sources means ipso facto that there is a direct use for them by environmental managers. Trouble is, as information providers, for the most part we don't really know what decisions managers face daily, nor is it a trivial matter to ascertain the effect of management decisions on the environment, at least in a time frame that facilitates timely maintenance and enhancement of decision support software. To bridge this gap in understanding, we conducted a Needs Assessment (using methodology from the NOAA/Coastal Services Center's Product Design and Evaluation training program) from December, 2011 through May, 2012, in which we queried 15 resource managers in southeast Florida to identify the types of climate data and information products they needed to understand the effects of climate change in their region of purview, and how best these products should be delivered and subsequently enhanced or corrected. Our intent has been to develop a suite of software and information products customized specifically for environmental managers. This report summarizes our success to date, including a report on the development of software for gathering and presenting specific types of climate data, and a narrative about how some U.S. government sponsored efforts, such as Giovanni and TerraVis, as well as non-governmental sponsored efforts such as Marxan, Zonation, SimCLIM, and other off-the-shelf software might be customized for use in specific regions.

  2. Vulnerability of Mediterranean Ecosystems to Long-Term Changes along the Coast of Israel

    PubMed Central

    Kaniewski, David; Van Campo, Elise; Morhange, Christophe; Guiot, Joël; Zviely, Dov; Le Burel, Sabine; Otto, Thierry; Artzy, Michal

    2014-01-01

    Although human activity is considered to be a major driving force affecting the distribution and dynamics of Mediterranean ecosystems, the full consequences of projected climate variability and relative sea-level changes on fragile coastal ecosystems for the next century are still unknown. It is unclear how these waterfront ecosystems can be sustained, as well as the services they provide, when relative sea-level rise and global warming are expected to exert even greater pressures in the near future (drought, habitat degradation and accelerated shoreline retreat). Haifa Bay, northern Israel, has recorded a landward sea invasion, with a maximum sea penetration 4,000 years ago, during an important period of urban development and climate instability. Here, we examine the cumulative pressure of climate shifts and relative sea-level changes in order to investigate the patterns and mechanisms behind forest replacement by an open-steppe. We provide a first comprehensive and integrative study for the southern Levant that shows that (i) human impact, through urbanization, has been the main driver behind ecological erosion in the past 4,000 years; (ii) climate pressures have reinforced this impact; and (iii) local coastal changes have played a decisive role in eroding ecosystem resilience. These three parameters, which have closely interacted during the last 4,000 years in Haifa Bay, clearly indicate that for an efficient management of the coastal habitats, anthropogenic pressures linked to urban development must be reduced in order to mitigate the predicted effects of Global Change. PMID:25003703

  3. Vulnerability of Mediterranean ecosystems to long-term changes along the coast of Israel.

    PubMed

    Kaniewski, David; Van Campo, Elise; Morhange, Christophe; Guiot, Joël; Zviely, Dov; Le Burel, Sabine; Otto, Thierry; Artzy, Michal

    2014-01-01

    Although human activity is considered to be a major driving force affecting the distribution and dynamics of Mediterranean ecosystems, the full consequences of projected climate variability and relative sea-level changes on fragile coastal ecosystems for the next century are still unknown. It is unclear how these waterfront ecosystems can be sustained, as well as the services they provide, when relative sea-level rise and global warming are expected to exert even greater pressures in the near future (drought, habitat degradation and accelerated shoreline retreat). Haifa Bay, northern Israel, has recorded a landward sea invasion, with a maximum sea penetration 4,000 years ago, during an important period of urban development and climate instability. Here, we examine the cumulative pressure of climate shifts and relative sea-level changes in order to investigate the patterns and mechanisms behind forest replacement by an open-steppe. We provide a first comprehensive and integrative study for the southern Levant that shows that (i) human impact, through urbanization, has been the main driver behind ecological erosion in the past 4,000 years; (ii) climate pressures have reinforced this impact; and (iii) local coastal changes have played a decisive role in eroding ecosystem resilience. These three parameters, which have closely interacted during the last 4,000 years in Haifa Bay, clearly indicate that for an efficient management of the coastal habitats, anthropogenic pressures linked to urban development must be reduced in order to mitigate the predicted effects of Global Change. PMID:25003703

  4. Ecosystem regime change inferred from the distribution of trace metals in Lake Erie sediments

    NASA Astrophysics Data System (ADS)

    Yuan, Fasong; Depew, Richard; Soltis-Muth, Cheryl

    2014-12-01

    Many freshwater and coastal marine ecosystems across the world may have undergone an ecosystem regime change due to a combination of rising anthropogenic disturbances and regional climate change. Such a change in aquatic ecosystems is commonly seen as shifts in algal species. But considerably less detail is known about the eutrophication history in terms of changes in algal productivity, particularly for a large lake with a great deal of spatial variability. Here we present an analysis of trace metals (Cu, Ni, Cd, and Pb) on a sediment core recovered from Lake Erie, off the Vermilion coast of northern Ohio, USA, to reconstruct the eutrophication history of the lake over the past 210 years. Following a slow eutrophication during European settlement, Lake Erie experienced a period of accelerated eutrophication, leading to an ecosystem regime transition into a eutrophic lake state in 1950. Our results suggested that the lake's biological productivity has ever since maintained fairly high even though a significant input reduction was realized from rigorous nutrient abatements that began as early as in 1969. This work underscored the role of in-lake biogeochemical cycling in nutrient dynamics of this already eutrophic lake.

  5. Climate change, plant traits, and invasion in natural and agricultural ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive species and climate change, each of which is likely to influence agricultural productivity and biological diversity, are also likely to interact. This chapter explores characteristics of both invasive plants and invaded ecosystems to search for generalizations that may allow us to predict w...

  6. Exploring spatiotemporal changes in ecosystem-service values and hotspots in China.

    PubMed

    Li, Guangdong; Fang, Chuanglin; Wang, Shaojian

    2016-03-01

    Although ecosystems are valuable, they have been allowed to deteriorate globally in recent decades. However, the spatiotemporal changes in ecosystem-service values (ESVs) and their hotspots in China are not well understood. Here, long-term land-cover data, the spatial analysis method and an econometric analysis model were used to examine these changes. The results indicate that the total terrestrial ESV decreased from US$2398.31 billion in 1990 to US$2347.56 billion in 2010 (converted to 2009 dollar values), which provides strong evidence for the tendency of ecosystems in China to deteriorate over time, albeit slightly. We also found that the changes in ESVs had significant spatial heterogeneity. Our analysis showed that the relationship between ESV and gross domestic product (GDP) is generally negative, but this relationship is not always fixed. The Loess Plateau, Guizhou, Hubei, Henan and Xinjiang continually presented concentrated hotspot areas of ESV changes, whereas coastal regions continually presented concentrated cold-spot areas. Overlap analyses and logistic regressions demonstrate that national ecological programs have clear effects on the improvement of ecosystems but that the effectiveness of different policies varies on spatial and temporal scales. The results of this study will support more effective decision-making around the implementation of ecological conservation policies. PMID:26760280

  7. Ecosystem regime change inferred from the distribution of trace metals in Lake Erie sediments

    PubMed Central

    Yuan, Fasong; Depew, Richard; Soltis-Muth, Cheryl

    2014-01-01

    Many freshwater and coastal marine ecosystems across the world may have undergone an ecosystem regime change due to a combination of rising anthropogenic disturbances and regional climate change. Such a change in aquatic ecosystems is commonly seen as shifts in algal species. But considerably less detail is known about the eutrophication history in terms of changes in algal productivity, particularly for a large lake with a great deal of spatial variability. Here we present an analysis of trace metals (Cu, Ni, Cd, and Pb) on a sediment core recovered from Lake Erie, off the Vermilion coast of northern Ohio, USA, to reconstruct the eutrophication history of the lake over the past 210 years. Following a slow eutrophication during European settlement, Lake Erie experienced a period of accelerated eutrophication, leading to an ecosystem regime transition into a eutrophic lake state in 1950. Our results suggested that the lake's biological productivity has ever since maintained fairly high even though a significant input reduction was realized from rigorous nutrient abatements that began as early as in 1969. This work underscored the role of in-lake biogeochemical cycling in nutrient dynamics of this already eutrophic lake. PMID:25434300

  8. Climate change impacts on terrestrial ecosystems in the multi-state region centered on Chicago

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes the potential impacts of warming temperatures and changing precipitation on plants wildlife, invasive species, pests and agricultural ecosystems across the multistate region centered on Chicago, Illinois. We define the region broadly to include several hundred kilometers. We c...

  9. Estimating Climate Change Impacts on Vegetation-based Ecosystem Services in the U.S.

    EPA Science Inventory

    The dynamic global vegetation model MC1 is being used to assess the potential impacts of climate change on vegetation and ecosystem services (e.g., biological sequestration, provisioning of grazing land, avoided forest fire suppression costs) in the U.S. MC1 projects the “potent...

  10. Ecosystem regime change inferred from the distribution of trace metals in Lake Erie sediments.

    PubMed

    Yuan, Fasong; Depew, Richard; Soltis-Muth, Cheryl

    2014-01-01

    Many freshwater and coastal marine ecosystems across the world may have undergone an ecosystem regime change due to a combination of rising anthropogenic disturbances and regional climate change. Such a change in aquatic ecosystems is commonly seen as shifts in algal species. But considerably less detail is known about the eutrophication history in terms of changes in algal productivity, particularly for a large lake with a great deal of spatial variability. Here we present an analysis of trace metals (Cu, Ni, Cd, and Pb) on a sediment core recovered from Lake Erie, off the Vermilion coast of northern Ohio, USA, to reconstruct the eutrophication history of the lake over the past 210 years. Following a slow eutrophication during European settlement, Lake Erie experienced a period of accelerated eutrophication, leading to an ecosystem regime transition into a eutrophic lake state in 1950. Our results suggested that the lake's biological productivity has ever since maintained fairly high even though a significant input reduction was realized from rigorous nutrient abatements that began as early as in 1969. This work underscored the role of in-lake biogeochemical cycling in nutrient dynamics of this already eutrophic lake. PMID:25434300

  11. Jackrabbit (Lepus californicus) herbivory changes dominance in desertified Chihuahuan Desert ecosystems.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study addressed the question: can herbivory by a medium size herbivore, black-tail jackrabbits (Lepus californicus), change dominance in desertified ecosystems dominated by two species of shrubs. Shrubs that were pruned by jackrabbits in plant communities dominated by creosotebush (Larrea tride...

  12. IMPACTS OF AIR POLLUTION AND CLIMATE CHANGE ON FOREST ECOSYSTEMS - EMERGING RESEARCH NEEDS

    EPA Science Inventory

    Outcomes from the 22nd meeting for Specialists in Air Pollution Effects on Forest Ecosystems "Forests under Anthropogenic Pressure - Effects of Air Pollution, Climate Change and Urban Development", September 10-16, 2006, Riverside, CA, USA are summarized. Tropospheric ozone is st...

  13. Rapid changes in water hardness and alkalinity: Calcite formation is lethal to Daphnia magna.

    PubMed

    Bogart, Sarah J; Woodman, Samuel; Steinkey, Dylan; Meays, Cindy; Pyle, Greg G

    2016-07-15

    There is growing concern that freshwater ecosystems may be negatively affected by ever-increasing anthropogenic inputs of extremely hard, highly alkaline effluent containing large quantities of Ca(2+), Mg(2+), CO3(2-), and HCO3(-) ions. In this study, the toxicity of rapid and extreme shifts in water hardness (38-600mg/L as CaCO3) and alkalinity (30-420mg/L as CaCO3) to Daphnia magna was tested, both independently and in combination. Within these ranges, where no precipitation event occurred, shifts in water hardness and/or alkalinity were not toxic to D. magna. In contrast, 98-100% of D. magna died within 96h after exposure to 600mg/L as CaCO3 water hardness and 420mg/L as CaCO3 alkalinity (LT50 of 60h with a 95% CI of 54.2-66.0h). In this treatment, a CaCO3 (calcite) precipitate formed in the water column which was ingested by and thoroughly coated the D. magna. Calcite collected from a mining impacted stream contained embedded organisms, suggesting field streams may also experience similar conditions and possibly increased mortality as observed in the lab tests. Although further investigation is required to determine the exact fate of aquatic organisms exposed to rapid calcite precipitation in the field, we caution that negative effects may occur more quickly or at lower concentrations of water hardness and alkalinity in which we observed effects in D. magna, because some species, such as aquatic insects, are more sensitive than cladocerans to changes in ionic strength. Our results provide evidence that both calcite precipitation and the major ion balance of waters should be managed in industrially affected ecosystems and we support the development of a hardness+alkalinity guideline for the protection of aquatic life. PMID:27060657

  14. Linking above and belowground responses to global change at community and ecosystem scales.

    SciTech Connect

    Antoninka, Anita; Wolf, Julie; Bowker, Matt; Classen, Aimee T; JohnsonPhD, Dr Nancy C

    2009-01-01

    Cryptic belowground organisms are difficult to observe and their responses to global changes are not well understood. Nevertheless, there is reason to believe that interactions among above- and belowground communities may mediate ecosystem responses to global change. We used grassland mesocosms to manipulate the abundance of one important group of soil organisms, arbuscular mycorrhizal (AM) fungi, and to study community and ecosystem responses to CO2 and N enrichment. After two growing seasons, biomass responses of plant communities were recorded, and soil community responses were measured using microscopy, phospholipid fatty acids (PLFA) and community-level physiological profiles (CLPP). Ecosystem responses were examined by measuring net primary production (NPP), evapotranspiration, total soil organic matter (SOM), and extractable mineral N. Structural equation modeling was used to examine the causal relationships among treatments and response variables. We found that while CO2 and N tended to directly impact ecosystem functions (evapotranspiration and NPP, respectively), AM fungi indirectly impacted ecosystem functions by strongly influencing the composition of plant and soil communities. For example, the presence of AM fungi had a strong influence on other root and soil fungi and soil bacteria. We found that the mycotrophic status of the dominant plant species in the mesocosms determined whether the presence of AM fungi increased or decreased NPP. Mycotrophic grasses dominated the mesocosm communities during the first growing season, and thus, the mycorrhizal treatments had the highest NPP. In contrast, non-mycotrophic forbs were dominant during the second growing season and thus, the mycorrhizal treatments had the lowest NPP. The composition of the plant community strongly influenced soil N; and the composition of the soil organisms strongly influenced SOM accumulation in the mesocosms. These results show how linkages between above- and belowground communities

  15. Can ecosystem-scale translocations mitigate the impact of climate change on terrestrial biodiversity? Promises, pitfalls, and possibilities: Ecosystem-scale translocations.

    PubMed

    Boyer, Stéphane; Case, Bradley S; Lefort, Marie-Caroline; Waterhouse, Benjamin R; Wratten, Stephen D

    2016-01-01

    Because ecological interactions are the first components of the ecosystem to be impacted by climate change, future forms of threatened-species and ecosystem management should aim at conserving complete, functioning communities rather than single charismatic species. A possible way forward is the deployment of ecosystem-scale translocation (EST), where above- and below-ground elements of a functioning terrestrial ecosystem (including vegetation and topsoil) are carefully collected and moved together. Small-scale attempts at such practice have been made for the purpose of ecological restoration. By moving larger subsets of functioning ecosystems from climatically unstable regions to more stable ones, EST could provide a practical means to conserve mature and complex ecosystems threatened by climate change. However, there are a number of challenges associated with EST in the context of climate change mitigation, in particular the choice of donor and receptor sites. With the aim of fostering discussion and debate about the EST concept, we  1) outline the possible promises and pitfalls of EST in mitigating the impact of climate change on terrestrial biodiversity and 2) use a GIS-based approach to illustrate how  potential source and receptor sites, where EST could be trialed and evaluated globally, could be identified. PMID:26989475

  16. Climate change and ecosystems dynamics over the last 6000 years in the Middle Atlas, Morocco

    NASA Astrophysics Data System (ADS)

    Nourelbait, Majda; Rhoujjati, Ali; Benkaddour, Abdelfattah; Carré, Matthieu; Eynaud, Frederique; Martinez, Philippe; Cheddadi, Rachid

    2016-04-01

    The present study aims at reconstructing past climate changes and their environmental impacts on plant ecosystems during the last 6000 years in the Middle Atlas, Morocco. Mean January temperature (Tjan), annual precipitation (Pann), winter (Pw) and summer (Ps) precipitation, and a seasonal index (SI) have all been quantified from a fossil pollen record. Several bio- and geo-chemical elements have also been analysed to evaluate the links between past climate, landscape, and ecosystem changes. Over the last 6000 years, climate has changed within a low temperature and precipitation range with a trend of aridity and warming towards the present. Tjan has varied within a ca. 2 °C range, and Pann within less than 100 mm yr-1. The long-term changes reconstructed in our record between 6 ka cal BP and today are consistent with the aridity trend observed in the Mediterranean basin. Despite the overall limited range of climate fluctuation, we observe major changes in the ecosystem composition, the carbon isotopic contents of organic matter (δ13C), the total organic carbon and nitrogen amount, and the carbon to nitrogen ratio (C / N) after ca. 3750 cal BP. The main ecosystem changes correspond to a noticeable transition in the conifer forest between the Atlas cedar, which expanded after 3750 cal BP, and the pine forest. These vegetation changes impacted the sedimentation type and its composition in the lake. Between 5500 and 5000 cal BP, we observe an abrupt change in all proxies which is coherent with a decrease in Tjan without a significant change in the overall amount of precipitation.

  17. Understanding the role of ecohydrological feedbacks in ecosystem state change in drylands

    USGS Publications Warehouse

    Turnbull, L.; Wilcox, B.P.; Belnap, J.; Ravi, S.; D'Odorico, P.; Childers, D.; Gwenzi, W.; Okin, G.; Wainwright, J.; Caylor, K.K.; Sankey, T.

    2012-01-01

    Ecohydrological feedbacks are likely to be critical for understanding the mechanisms by which changes in exogenous forces result in ecosystem state change. We propose that in drylands, the dynamics of ecosystem state change are determined by changes in the type (stabilizing vs amplifying) and strength of ecohydrological feedbacks following a change in exogenous forces. Using a selection of five case studies from drylands, we explore the characteristics of ecohydrological feedbacks and resulting dynamics of ecosystem state change. We surmise that stabilizing feedbacks are critical for the provision of plant-essential resources in drylands. Exogenous forces that break these stabilizing feedbacks can alter the state of the system, although such changes are potentially reversible if strong amplifying ecohydrological feedbacks do not develop. The case studies indicate that if amplifying ecohydrological feedbacks do develop, they are typically associated with abiotic processes such as runoff, erosion (by wind and water), and fire. These amplifying ecohydrological feedbacks progressively modify the system in ways that are long-lasting and possibly irreversible on human timescales.

  18. Diverse responses of phenology to global changes in a grassland ecosystem

    PubMed Central

    Cleland, Elsa E.; Chiariello, Nona R.; Loarie, Scott R.; Mooney, Harold A.; Field, Christopher B.

    2006-01-01

    Shifting plant phenology (i.e., timing of flowering and other developmental events) in recent decades establishes that species and ecosystems are already responding to global environmental change. Earlier flowering and an extended period of active plant growth across much of the northern hemisphere have been interpreted as responses to warming. However, several kinds of environmental change have the potential to influence the phenology of flowering and primary production. Here, we report shifts in phenology of flowering and canopy greenness (Normalized Difference Vegetation Index) in response to four experimentally simulated global changes: warming, elevated CO2, nitrogen (N) deposition, and increased precipitation. Consistent with previous observations, warming accelerated both flowering and greening of the canopy, but phenological responses to the other global change treatments were diverse. Elevated CO2 and N addition delayed flowering in grasses, but slightly accelerated flowering in forbs. The opposing responses of these two important functional groups decreased their phenological complementarity and potentially increased competition for limiting soil resources. At the ecosystem level, timing of canopy greenness mirrored the flowering phenology of the grasses, which dominate primary production in this system. Elevated CO2 delayed greening, whereas N addition dampened the acceleration of greening caused by warming. Increased precipitation had no consistent impacts on phenology. This diversity of phenological changes, between plant functional groups and in response to multiple environmental changes, helps explain the diversity in large-scale observations and indicates that changing temperature is only one of several factors reshaping the seasonality of ecosystem processes. PMID:16954189

  19. Rapid Changes of Large Tidewater Glaciers in SE Greenland

    NASA Astrophysics Data System (ADS)

    Stearns, L. A.; Hamilton, G. S.

    2005-12-01

    New field and satellite remote sensing measurements show that Kangerdlugssuaq Glacier and Helheim Glacier, two fast-flowing tidewater glaciers in South-East Greenland, accelerated 40-300% between 2001 and 2005 and retreated 3-5 km since July 2003. Together, the catchment basins of these two glaciers encompass ~10% of the area of the Greenland ice sheet. Previous studies observed rates of surface lowering on the main trunks of both glaciers that were too large to be caused by enhanced surface melting or decreased snow fall alone. One hypothesis to explain the thinning rates is a change in ice dynamics. We use repeat satellite imagery and published reports to reconstruct the last ~decade of flow histories for both glaciers and compare the results with velocities derived from field GPS surveys in the summer 2005. Helheim Glacier was flowing at ~8 km/yr in 1995 and 2001. In 2005, flow speeds were ~11.7 km/yr, a ~40% increase. The acceleration of Kangerdlugssuaq Glacier was more substantial. Portions of the main trunk that were flowing at ~5 km/yr in 1988, 1996 and 2001 were flowing at ~14 km/yr in summer 2005, an almost threefold increase. The accelerations in flow speeds were accompanied by other changes, including the rapid retreat of calving fronts that had maintained quasi-stable positions for the previous ~40 years, and a lowering of the ice surface by about 100 m, leaving stranded ice on adjacent ridges. The rapid thinning, acceleration and retreat of these two relatively nearby glaciers suggests a common triggering mechanism, such as enhanced surface melting due to regional climate warming. The current flow speeds, ~11 - 14 km/yr at the terminus, are too fast to be caused solely by internal deformation of the ice, implying that an increase in basal sliding forced by additional meltwater production is the probable cause of the velocity increases. The new observations and the hypothesized cause highlight the sensitivity of large outlet glaciers to local climate

  20. Glucose induces rapid changes in the secretome of Saccharomyces cerevisiae

    PubMed Central

    2014-01-01

    Background Protein secretion is a fundamental process in all living cells. Proteins can either be secreted via the classical or non-classical pathways. In Saccharomyces cerevisiae, gluconeogenic enzymes are in the extracellular fraction/periplasm when cells are grown in media containing low glucose. Following a transfer of cells to high glucose media, their levels in the extracellular fraction are reduced rapidly. We hypothesized that changes in the secretome were not restricted to gluconeogenic enzymes. The goal of the current study was to use a proteomic approach to identify extracellular proteins whose levels changed when cells were transferred from low to high glucose media. Results We performed two iTRAQ experiments and identified 347 proteins that were present in the extracellular fraction including metabolic enzymes, proteins involved in oxidative stress, protein folding, and proteins with unknown functions. Most of these proteins did not contain typical ER-Golgi signal sequences. Moreover, levels of many of these proteins decreased upon a transfer of cells from media containing low to high glucose media. Using an extraction procedure and Western blotting, we confirmed that the metabolic enzymes (glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, glucose-6-phosphate dehydrogenase, pyruvate decarboxylase), proteins involved in oxidative stress (superoxide dismutase and thioredoxin), and heat shock proteins (Ssa1p, Hsc82p, and Hsp104p) were in the extracellular fraction during growth in low glucose and that the levels of these extracellular proteins were reduced when cells were transferred to media containing high glucose. These proteins were associated with membranes in vesicle-enriched fraction. We also showed that small vesicles were present in the extracellular fraction in cells grown in low glucose. Following a transfer from low to high glucose media for 30 minutes, 98% of these vesicles disappeared from the extracellular fraction

  1. Response of western mountain ecosystems to climatic variability and change: the Western Mountain Initiative

    USGS Publications Warehouse

    Stephenson, Nathan L.; Peterson, Dave; Fagre, Daniel B.; Allen, Craig D.; McKenzie, Donald; Baron, Jill S.; O'Brian, Kelly

    2007-01-01

    Mountain ecosystems within our national parks and other protected areas provide valuable goods and services such as clean water, biodiversity conservation, and recreational opportunities, but their potential responses to expected climatic changes are inadequately understood. The Western Mountain Initiative (WMI) is a collaboration of scientists whose research focuses on understanding and predicting responses of western mountain ecosystems to climatic variability and change. It is a legacy of the Global Change Research Program initiated by the National Park Service (NPS) in 1991 and continued by the U.S. Geological Survey (USGS) to this day as part of the U.S. Climate Change Science Program (http://www.climatescience.gov/). All WMI scientists are active participants in CIRMOUNT, and seek to further its goals.

  2. Response of western mountain ecosystems to climatic variability and change: The Western Mountain Initiative

    USGS Publications Warehouse

    Stephenson, Nathan L.; Peterson, David A.; Fagre, Daniel B.; Allen, Craig; McKenzie, Donald; Baron, Jill; O'Brien, K.

    2006-01-01

    Mountain ecosystems within our national parks and other protected areas provide valuable goods and services such as clean water, biodiversity conservation, and recreational opportunities, but their potential responses to expected climatic changes are inadequately understood. The Western Mountain Initiative (WMI) is a collaboration of scientists whose research focuses on understanding and predicting responses of western mountain ecosystems to climatic variability and change. It is a legacy of the Global Change Research Program initiated by the National Park Service (NPS) in 1991 and continued by the U.S. Geological Survey (USGS) to this day as part of the U.S. Climate Change Science Program (http://www.climatescience.gov/). All WMI scientists are active participants in CIRMOUNT, and seek to further its goals.

  3. Changes in the ecosystem structure of the Black Sea under predicted climatological and anthropogenic variations

    NASA Astrophysics Data System (ADS)

    Akoglu, Ekin; Salihoglu, Baris; Fach Salihoglu, Bettina; Libralato, Simone; Cannaby, Heather; Oguz, Temel; Solidoro, Cosimo

    2014-05-01

    A dynamic Ecopath with Ecosim higher-trophic-level (HTL) model representation of the Black Sea ecosystem was coupled to the physical (BIMS-CIR) and biogeochemical (BIMS-ECO) models of the Black Sea in order to investigate historical anthropogenic and climatological interactions and feedbacks in the ecosystem. Further, the coupled models were used to assess the likely consequences of these interactions on the ecosystem's structure and functioning under predicted future climate (IPCC A1B) and fishing variability. Therefore, two model scenarios were used; i) a hindcast scenario (1980-1999) to evaluate and understand the impacts of the short-term climate and physical variability and the introduction of invasive species on the Black Sea ecosystem, and ii) a forecast scenario (2080-2099) to investigate the potential implications of climate change and anthropogenic exploitation on living resources of the Black Sea ecosystem by the end of the 21st century. According to the outcomes of the hindcast simulation, fisheries were found to be the main driver in determining the structure and functioning of the Black Sea ecosystem under changing environmental conditions. The coupled physical-biogeochemical forecast simulations predicted a slight but statistically significant basin-wide increase in the Black Sea's primary productivity by the end of the century due to increased stratification induced by basin-wide temperature increase and reduced Cold Intermediate Layer (CIL) formation which increased the residence time of riverine nutrients within the euphotic zone. Despite this increased primary productivity, the HTL model forecast simulation predicted a significant decrease in the commercial fish stocks primarily due to fisheries exploitation if current catch rates are maintained into the future. Results further suggested that some economically important small pelagic fish species are likely to disappear from the ecosystem making the recovery of the already-collapsed piscivorous

  4. Climate change and geothermal ecosystems: natural laboratories, sentinel systems, and future refugia.

    PubMed

    O'Gorman, Eoin J; Benstead, Jonathan P; Cross, Wyatt F; Friberg, Nikolai; Hood, James M; Johnson, Philip W; Sigurdsson, Bjarni D; Woodward, Guy

    2014-11-01

    Understanding and predicting how global warming affects the structure and functioning of natural ecosystems is a key challenge of the 21st century. Isolated laboratory and field experiments testing global change hypotheses have been criticized for being too small-scale and overly simplistic, whereas surveys are inferential and often confound temperature with other drivers. Research that utilizes natural thermal gradients offers a more promising approach and geothermal ecosystems in particular, which span a range of temperatures within a single biogeographic area, allow us to take the laboratory into nature rather than vice versa. By isolating temperature from other drivers, its ecological effects can be quantified without any loss of realism, and transient and equilibrial responses can be measured in the same system across scales that are not feasible using other empirical methods. Embedding manipulative experiments within geothermal gradients is an especially powerful approach, informing us to what extent small-scale experiments can predict the future behaviour of real ecosystems. Geothermal areas also act as sentinel systems by tracking responses of ecological networks to warming and helping to maintain ecosystem functioning in a changing landscape by providing sources of organisms that are preadapted to different climatic conditions. Here, we highlight the emerging use of geothermal systems in climate change research, identify novel research avenues, and assess their roles for catalysing our understanding of ecological and evolutionary responses to global warming. PMID:24729541

  5. Land use intensification alters ecosystem multifunctionality via loss of biodiversity and changes to functional composition.

    PubMed

    Allan, Eric; Manning, Pete; Alt, Fabian; Binkenstein, Julia; Blaser, Stefan; Blüthgen, Nico; Böhm, Stefan; Grassein, Fabrice; Hölzel, Norbert; Klaus, Valentin H; Kleinebecker, Till; Morris, E Kathryn; Oelmann, Yvonne; Prati, Daniel; Renner, Swen C; Rillig, Matthias C; Schaefer, Martin; Schloter, Michael; Schmitt, Barbara; Schöning, Ingo; Schrumpf, Marion; Solly, Emily; Sorkau, Elisabeth; Steckel, Juliane; Steffen-Dewenter, Ingolf; Stempfhuber, Barbara; Tschapka, Marco; Weiner, Christiane N; Weisser, Wolfgang W; Werner, Michael; Westphal, Catrin; Wilcke, Wolfgang; Fischer, Markus

    2015-08-01

    Global change, especially land-use intensification, affects human well-being by impacting the delivery of multiple ecosystem services (multifunctionality). However, whether biodiversity loss is a major component of global change effects on multifunctionality in real-world ecosystems, as in experimental ones, remains unclear. Therefore, we assessed biodiversity, functional composition and 14 ecosystem services on 150 agricultural grasslands differing in land-use intensity. We also introduce five multifunctionality measures in which ecosystem services were weighted according to realistic land-use objectives. We found that indirect land-use effects, i.e. those mediated by biodiversity loss and by changes to functional composition, were as strong as direct effects on average. Their strength varied with land-use objectives and regional context. Biodiversity loss explained indirect effects in a region of intermediate productivity and was most damaging when land-use objectives favoured supporting and cultural services. In contrast, functional composition shifts, towards fast-growing plant species, strongly increased provisioning services in more inherently unproductive grasslands. PMID:26096863

  6. Ecosystem heterogeneity determines the ecological resilience of the Amazon to climate change

    PubMed Central

    Longo, Marcos; Baccini, Alessandro; Phillips, Oliver L.; Lewis, Simon L.; Alvarez-Dávila, Esteban; Segalin de Andrade, Ana Cristina; Brienen, Roel J. W.; Erwin, Terry L.; Feldpausch, Ted R.; Monteagudo Mendoza, Abel Lorenzo; Nuñez Vargas, Percy; Prieto, Adriana; Silva-Espejo, Javier Eduardo; Malhi, Yadvinder; Moorcroft, Paul R.

    2016-01-01

    Amazon forests, which store ∼50% of tropical forest carbon and play a vital role in global water, energy, and carbon cycling, are predicted to experience both longer and more intense dry seasons by the end of the 21st century. However, the climate sensitivity of this ecosystem remains uncertain: several studies have predicted large-scale die-back of the Amazon, whereas several more recent studies predict that the biome will remain largely intact. Combining remote-sensing and ground-based observations with a size- and age-structured terrestrial ecosystem model, we explore the sensitivity and ecological resilience of these forests to changes in climate. We demonstrate that water stress operating at the scale of individual plants, combined with spatial variation in soil texture, explains observed patterns of variation in ecosystem biomass, composition, and dynamics across the region, and strongly influences the ecosystem’s resilience to changes in dry season length. Specifically, our analysis suggests that in contrast to existing predictions of either stability or catastrophic biomass loss, the Amazon forest’s response to a drying regional climate is likely to be an immediate, graded, heterogeneous transition from high-biomass moist forests to transitional dry forests and woody savannah-like states. Fire, logging, and other anthropogenic disturbances may, however, exacerbate these climate change-induced ecosystem transitions. PMID:26711984

  7. Effects of disturbance and climate change on ecosystem performance in the Yukon River Basin boreal forest

    USGS Publications Warehouse

    Wylie, Bruce K.; Rigge, Matthew B.; Brisco, Brian; Mrnaghan, Kevin; Rover, Jennifer R.; Long, Jordan

    2014-01-01

    A warming climate influences boreal forest productivity, dynamics, and disturbance regimes. We used ecosystem models and 250 m satellite Normalized Difference Vegetation Index (NDVI) data averaged over the growing season (GSN) to model current, and estimate future, ecosystem performance. We modeled Expected Ecosystem Performance (EEP), or anticipated productivity, in undisturbed stands over the 2000–2008 period from a variety of abiotic data sources, using a rule-based piecewise regression tree. The EEP model was applied to a future climate ensemble A1B projection to quantify expected changes to mature boreal forest performance. Ecosystem Performance Anomalies (EPA), were identified as the residuals of the EEP and GSN relationship and represent performance departures from expected performance conditions. These performance data were used to monitor successional events following fire. Results suggested that maximum EPA occurs 30–40 years following fire, and deciduous stands generally have higher EPA than coniferous stands. Mean undisturbed EEP is projected to increase 5.6% by 2040 and 8.7% by 2070, suggesting an increased deciduous component in boreal forests. Our results contribute to the understanding of boreal forest successional dynamics and its response to climate change. This information enables informed decisions to prepare for, and adapt to, climate change in the Yukon River Basin forest.

  8. Rapid Middle Eocene temperature change in western North America

    NASA Astrophysics Data System (ADS)

    Methner, Katharina; Mulch, Andreas; Fiebig, Jens; Wacker, Ulrike; Gerdes, Axel; Graham, Stephan A.; Chamberlain, C. Page

    2016-09-01

    Eocene hyperthermals are among the most enigmatic phenomena of Cenozoic climate dynamics. These hyperthermals represent temperature extremes superimposed on an already warm Eocene climate and dramatically affected the marine and terrestrial biosphere, yet our knowledge of temperature and rainfall in continental interiors is still rather limited. We present stable isotope (δ18O) and clumped isotope temperature (Δ47) records from a middle Eocene (41 to 40 Ma) high-elevation mammal fossil locality in the North American continental interior (Montana, USA). Δ47 paleotemperatures of soil carbonates delineate a rapid +9/-11 °C temperature excursion in the paleosol record. Δ47 temperatures progressively increase from 23 °C ± 3 °C to peak temperatures of 32 °C ± 3 °C and subsequently drop by 11 °C. This hyperthermal event in the middle Eocene is accompanied by low δ18O values and reduced pedogenic carbonate concentrations in paleosols. Based on laser ablation U/Pb geochronology of paleosol carbonates in combination with magnetostratigraphy, biostratigraphy, stable isotope, and Δ47 evidence, we suggest that this pronounced warming event reflects the Middle Eocene Climatic Optimum (MECO) in western North America. The terrestrial expression of northern hemisphere MECO in western North America appears to be characterized by warmer and wetter (sub-humid) conditions, compared to the post-MECO phase. Large and rapid shifts in δ18O values of precipitation and pedogenic CaCO3 contents parallel temperature changes, indicating the profound impact of the MECO on atmospheric circulation and rainfall patterns in the western North American continental interior during this transient warming event.

  9. Human relations with soil are changing rapidly: SSSA's new Work Group on Soil Change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humanity has rapidly become Earth’s chief agent of soil change, and geologists have named the epoch in which we live the Anthropocene, due to the global scale of human impact on the environment, including soil. In response to the increasing influence of humans on soil processes, the disciplines of ...

  10. Contemporary mire net ecosystem green-house gas balance: controls and susceptibility to change

    NASA Astrophysics Data System (ADS)

    Nilsson, Mats; Eriksson, Tobias; Grelle, Achim; Larsson, Anna; Laudon, Hjalmar; Lindroth, Anders; Ottosson-Löfvenius, Mikaell; Peichl, Matthias; Sagerfors, Jörgen; Ågren, Anneli; Öquist, Mats

    2015-04-01

    In this presentation I will address three main issues: 1 - What is the contemporary carbon sequestration function of high latitude mire ecosystems relative to Holocene average? 2 - The relative importance of the component carbon (C) fluxes for the annual mire Net Ecosystem Carbon Balance (NECB); 3 - The importance of gross primary production (GPP) versus ecosystem respiration (Reco) for the annual Net Ecosystem Exchange (NEE); The annual boreal mire NECB is made up principally by the biosphere-atmosphere exchange of CO2 (NEE) and CH4 and the runoff C-export. One important research issue is to further understand what controls the relative contribution from the component fluxes to the annual mire NECB. A second important major research issue is to reveal the relative importance of gross photosynthesis (GPP) and ecosystem respiration (Reco) respectively for the annual mire NEE. The relative importance of GPP and Reco respectively for the NECB also encounters the effect of changes in the lengths of the growing season and non-growing season respectively. In this presentation we use ten years of data on annual fluxes of NEE, methane and water discharge C export at a nutrient poor minerogenic boreal mire, Degerö Stormyr, in northern Sweden to address the above questions. Winter time NEE together with methane emission and water discharge C export reduces the growing season NEE with approximately 60%, thus substantially controlling the annual boreal mire NEE.

  11. Early results from the Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility Project

    USGS Publications Warehouse

    Brock, John C.; Lavoie, Dawn L.; Poore, Richard Z.

    2011-01-01

    The northern Gulf of Mexico coastal region and its diverse ecosystems are threatened by population and development pressure and by the impacts of rising sea level and severe storms such as the series of hurricanes that has impacted the northern Gulf in recent years. In response to the complex management issues facing the region, the U.S. Geological Survey (USGS) organized a multidisciplinary research program to coordinate the activities of USGS and other scientists working in the northern Gulf of Mexico region (fig. 1). The Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility Project aims to develop a thorough understanding of the dynamic coastal ecosystems on the northern Gulf coast, the impact of human activities on these ecosystems, and the vulnerability of ecosystems and human communities to more frequent and more intense hurricanes in the future. A special issue of Geo-Marine Letters published in December 2009 is devoted to early results of studies completed as part of this project. These studies, which have been conducted at sites throughout the northern Gulf region, from the Chandeleur Islands to Apalachicola Bay, have focused on three themes: (1) The underlying geologic framework that exerts controls over coastal processes (2) The impact of human activities on nearshore water quality (3) Hurricanes and associated effects

  12. Rapid Changes in the Sodium Atmosphere of Mercury

    NASA Astrophysics Data System (ADS)

    Potter, A. E.; Killen, R. M.; Morgan, T. H.

    1998-09-01

    We imaged Mercury in sodium D1 and D2 emission for six days during the period November 13-20, 1997 using a 10x10 arcsec aperture image slicer coupled to a high-resolution spectrograph. During the period of observation, large daily changes took place in both the total amount of sodium and its distribution over the planet. In 24 hours, from November 13 to November 14, the total amount of sodium on Mercury doubled. By November 20, the total sodium amount had tripled relative to that of November 13. We corrected the sodium images for atmospheric smearing by computing the actual seeing function from surface reflection images, and using this function to correct the sodium images. The resulting images showed sodium emission to be brightest at longitudes near the subsolar longitude at about 140 degrees. There are no obviously outstanding geologic features at this longitude. On November 15, sodium was excess at southern latitudes. On November 16, the excess moved to northern latitudes, and then changed back to southern latitudes by November 18. In order to explain the large and rapid changes in the amount of sodium, and the shift of excess sodium from southern latitudes to northern latitudes, and back again, we suggest that sodium is released from the surface by magnetospheric processes, perhaps initiated by CME events that expose the planet's surface to solar particles (Luhmann, et al., 1998). CME activity was high during this period of observation. References: Luhmann, et al. (1998), Disturbances in Mercury's magnetosphere: Are the Mariner 10 `substorms' simply driven?, JGR 103 9113

  13. The Southern Ocean ecosystem under multiple climate change stresses--an integrated circumpolar assessment.

    PubMed

    Gutt, Julian; Bertler, Nancy; Bracegirdle, Thomas J; Buschmann, Alexander; Comiso, Josefino; Hosie, Graham; Isla, Enrique; Schloss, Irene R; Smith, Craig R; Tournadre, Jean; Xavier, José C

    2015-04-01

    A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on the marine ecosystem shows: (i) large proportions of the SO are and will be affected by one or more climate change processes; areas projected to be affected in the future are larger than areas that are already under environmental stress, (ii) areas affected by changes in sea-ice in the past and likely in the future are much larger than areas affected by ocean warming. The smallest areas (<1% area of the SO) are affected by glacier retreat and warming in the deeper euphotic layer. In the future, decrease in the sea-ice is expected to be widespread. Changes in iceberg impact resulting from further collapse of ice-shelves can potentially affect large parts of shelf and ephemerally in the off-shore regions. However, aragonite undersaturation (acidification) might become one of the biggest problems for the Antarctic marine ecosystem by affecting almost the entire SO. Direct and indirect impacts of various environmental changes to the three major habitats, sea-ice, pelagic and benthos and their biota are complex. The areas affected by environmental stressors range from 33% of the SO for a single stressor, 11% for two and 2% for three, to <1% for four and five overlapping factors. In the future, areas expected to be affected by 2 and 3 overlapping factors are equally large, including potential iceberg changes, and together cover almost 86% of the SO ecosystem. PMID:25369312

  14. The response of terrestrial ecosystems to global climate change: towards an integrated approach.

    PubMed

    Rustad, Lindsey E

    2008-10-15

    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 international policies regulating carbon sequestration and greenhouse gas emissions. This paper reflects on the nature of current global change experiments, and provides recommendations for a unified multidisciplinary approach to future research in this dynamic field. These recommendations include: (1) better integration between experiments and models, and amongst experimental, monitoring, and space-for-time studies; (2) stable and increased support for long-term studies and multi-factor experiments; (3) explicit inclusion of biodiversity, disturbance, and extreme events in experiments and models; (4) consideration of timing vs intensity of global change factors in experiments and models; (5) evaluation of potential thresholds or ecosystem 'tipping points'; and (6) increased support for model-model and model-experiment comparisons. These recommendations, which reflect discussions within the TERACC international network of global change scientists, will facilitate the unraveling of the complex direct and indirect effects of global climate change on terrestrial ecosystems and their components. PMID:18675444

  15. Effects of solar ultraviolet radiation on terrestrial ecosystems. Patterns, mechanisms, and interactions with climate change.

    PubMed

    Ballaré, C L; Caldwell, M M; Flint, S D; Robinson, S A; Bornman, J F

    2011-02-01

    Ultraviolet radiation (UV) is a minor fraction of the solar spectrum reaching the ground surface. In this assessment we summarize the results of previous work on the effects of the UV-B component (280-315 nm) on terrestrial ecosystems, and draw attention to important knowledge gaps in our understanding of the interactive effects of UV radiation and climate change. We highlight the following points: (i) The effects of UV-B on the growth of terrestrial plants are relatively small and, because the Montreal Protocol has been successful in limiting ozone depletion, the reduction in plant growth caused by increased UV-B radiation in areas affected by ozone decline since 1980 is unlikely to have exceeded 6%. (ii) Solar UV-B radiation has large direct and indirect (plant-mediated) effects on canopy arthropods and microorganisms. Therefore, trophic interactions (herbivory, decomposition) in terrestrial ecosystems appear to be sensitive to variations in UV-B irradiance. (iii) Future variations in UV radiation resulting from changes in climate and land-use may have more important consequences on terrestrial ecosystems than the changes in UV caused by ozone depletion. This is because the resulting changes in UV radiation may affect a greater range of ecosystems, and will not be restricted solely to the UV-B component. (iv) Several ecosystem processes that are not particularly sensitive to UV-B radiation can be strongly affected by UV-A (315-400 nm) radiation. One example is the physical degradation of plant litter. Increased photodegradation (in response to reduced cloudiness or canopy cover) will lead to increased carbon release to the atmosphere via direct and indirect mechanisms. PMID:21253661

  16. Phenology, Ecosystem Processes, and Climate Change: What We Are Learning from the Phenocam Network

    NASA Astrophysics Data System (ADS)

    Richardson, A. D.

    2014-12-01

    Phenology has been shown to be a robust integrator of the effects of year-to-year climate variability and longer-term climate change on natural systems. At the level of organisms, phenology plays a critical role in processes related to growth, reproduction, and competition. At the level of ecosystems, phenology is important because of implications for productivity, carbon sequestration, nutrient cycling, and feedbacks to the climate system. At decadal-to-century time scales, climate change will indirectly cause additional shifts in ecosystem phenology via shifts in community composition and structure. There is a demonstrated need to better document biological responses to a changing world, and improved phenological monitoring will contribute to achieving this goal. In this talk, I will describe a collaborative research network called "PhenoCam" (http://phenocam.sr.unh.edu/). PhenoCam uses networked digital cameras - webcams - for phenological monitoring in a range of ecosystems (over 100 sites, and 300+ site-years of archived data) across the North American continent. These sites range from coastal wetlands of the southeast to mountain highlands of the northwest, and from the hot deserts of Arizona to the cold of arctic Alaska. Images are captured every 30 minutes, are uploaded to the PhenoCam server for display in real-time, and are then processed to yield measures of vegetation greenness. I will discuss how we are using data from PhenoCam (1) to improve understanding of the environmental controls on phenology at organism-to-ecosystem scales; (2) to relate ecosystem processes (e.g. carbon and water fluxes measured via eddy covariance) to phenology; and (3) to develop predictive models and forecast future climate change impacts on phenology.

  17. Transitions in Arctic ecosystems: Ecological implications of a changing hydrological regime

    NASA Astrophysics Data System (ADS)

    Wrona, Frederick J.; Johansson, Margareta; Culp, Joseph M.; Jenkins, Alan; Mârd, Johanna; Myers-Smith, Isla H.; Prowse, Terry D.; Vincent, Warwick F.; Wookey, Philip A.

    2016-03-01

    Numerous international scientific assessments and related articles have, during the last decade, described the observed and potential impacts of climate change as well as other related environmental stressors on Arctic ecosystems. There is increasing recognition that observed and projected changes in freshwater sources, fluxes, and storage will have profound implications for the physical, biogeochemical, biological, and ecological processes and properties of Arctic terrestrial and freshwater ecosystems. However, a significant level of uncertainty remains in relation to forecasting the impacts of an intensified hydrological regime and related cryospheric change on ecosystem structure and function. As the terrestrial and freshwater ecology component of the Arctic Freshwater Synthesis, we review these uncertainties and recommend enhanced coordinated circumpolar research and monitoring efforts to improve quantification and prediction of how an altered hydrological regime influences local, regional, and circumpolar-level responses in terrestrial and freshwater systems. Specifically, we evaluate (i) changes in ecosystem productivity; (ii) alterations in ecosystem-level biogeochemical cycling and chemical transport; (iii) altered landscapes, successional trajectories, and creation of new habitats; (iv) altered seasonality and phenological mismatches; and (v) gains or losses of species and associated trophic interactions. We emphasize the need for developing a process-based understanding of interecosystem interactions, along with improved predictive models. We recommend enhanced use of the catchment scale as an integrated unit of study, thereby more explicitly considering the physical, chemical, and ecological processes and fluxes across a full freshwater continuum in a geographic region and spatial range of hydroecological units (e.g., stream-pond-lake-river-near shore marine environments).

  18. Ecosystem Responses to Changed Atmospheric Mercury Load: Results from Seven Years of Mercury Loading to Lake 658

    NASA Astrophysics Data System (ADS)

    Gilmour, C.; Harris, R.; Kelly, C.; Rudd, J.; Amyot, M.; Hurley, J.; Babiarz, C.; Paterson, M.; Blanchfield, P.; Beaty, K.; Sandilands, K.; Hintelmann, H.; Krabbenhoft, D.; Tate, M.; Lindberg, S.; Southworth, G.; St. Louis, V.; Graydon, J.

    2009-05-01

    The response of fish methylmercury concentrations to changes in mercury deposition has been difficult to establish because sediments/soils contain large pools of historical contamination, and many factors in addition to deposition affect fish mercury. To test directly the response of fish contamination to changing mercury deposition, we are conducting the METAALICUS study, a whole-ecosystem experiment, increasing the mercury load to a lake and its watershed by the addition of enriched stable mercury isotopes. The isotopes allowed us to distinguish between experimentally applied mercury and mercury already present in the ecosystem and to examine bioaccumulation of mercury deposited to different parts of the watershed. Loading began in 2001 and ended in 2007. In this paper we will present mercury and methylmercury budgets for the study lake for the entire 7 year loading period. Overall, we increased the total Hg load to L658 and its watershed by roughly a factor of 3. However, we only increased the Hg load the lake itself by about 2X, since, during the seven years of addition, almost none of the Hg spike deposited to the watershed was transported all the way to the lake. Spike Hg concentrations in lake water rose each year during the open-water loading period and declined rapidly each winter. Methylmercury production in the lake responded rapidly to changes in mercury load during the first year of addition. After about 3 years, the increase in MeHg in lake water and in surface sediments slowed, suggesting that MeHg production was approaching a new level, or different rate, in response to the increased Hg load. We will discuss major input and loss terms for newly deposited Hg, the timing and proportionality of response, the timing and locations of MeHg production within the lake.

  19. Critical research needs for identifying future changes in Gulf coral reef ecosystems

    PubMed Central

    Feary, David A.; Burt, John A.; Bauman, Andrew G.; Al Hazeem, Shaker; Abdel-Moati, Mohamed A.; Al-Khalifa, Khalifa A.; Anderson, Donald M.; Amos, Carl; Baker, Andrew; Bartholomew, Aaron; Bento, Rita; Cavalcante, Geórgenes H.; Chen, Chaolun Allen; Coles, Steve L.; Dab, Koosha; Fowler, Ashley M.; George, David; Grandcourt, Edwin; Hill, Ross; John, David M.; Jones, David A.; Keshavmurthy, Shashank; Mahmoud, Huda; Moradi Och Tapeh, Mahdi; Mostafavi, Pargol Ghavam; Naser, Humood; Pichon, Michel; Purkis, Sam; Riegl, Bernhard; Samimi-Namin, Kaveh; Sheppard, Charles; Vajed Samiei, Jahangir; Voolstra, Christian R.; Wiedenmann, Joerg

    2014-01-01

    Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/ Persian Gulf (thereafter ‘Gulf’) coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. PMID:23643407

  20. Critical research needs for identifying future changes in Gulf coral reef ecosystems.

    PubMed

    Feary, David A; Burt, John A; Bauman, Andrew G; Al Hazeem, Shaker; Abdel-Moati, Mohamed A; Al-Khalifa, Khalifa A; Anderson, Donald M; Amos, Carl; Baker, Andrew; Bartholomew, Aaron; Bento, Rita; Cavalcante, Geórgenes H; Chen, Chaolun Allen; Coles, Steve L; Dab, Koosha; Fowler, Ashley M; George, David; Grandcourt, Edwin; Hill, Ross; John, David M; Jones, David A; Keshavmurthy, Shashank; Mahmoud, Huda; Moradi Och Tapeh, Mahdi; Mostafavi, Pargol Ghavam; Naser, Humood; Pichon, Michel; Purkis, Sam; Riegl, Bernhard; Samimi-Namin, Kaveh; Sheppard, Charles; Vajed Samiei, Jahangir; Voolstra, Christian R; Wiedenmann, Joerg

    2013-07-30

    Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/Persian Gulf (thereafter 'Gulf') coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. PMID:23643407

  1. Projected land-use change impacts on ecosystem services in the United States.

    PubMed

    Lawler, Joshua J; Lewis, David J; Nelson, Erik; Plantinga, Andrew J; Polasky, Stephen; Withey, John C; Helmers, David P; Martinuzzi, Sebastián; Pennington, Derric; Radeloff, Volker C

    2014-05-20

    Providing food, timber, energy, housing, and other goods and services, while maintaining ecosystem functions and biodiversity that underpin their sustainable supply, is one of the great challenges of our time. Understanding the drivers of land-use change and how policies can alter land-use change will be critical to meeting this challenge. Here we project land-use change in the contiguous United States to 2051 under two plausible baseline trajectories of economic conditions to illustrate how differences in underlying market forces can have large impacts on land-use with cascading effects on ecosystem services and wildlife habitat. We project a large increase in croplands (28.2 million ha) under a scenario with high crop demand mirroring conditions starting in 2007, compared with a loss of cropland (11.2 million ha) mirroring conditions in the 1990s. Projected land-use changes result in increases in carbon storage, timber production, food production from increased yields, and >10% decreases in habitat for 25% of modeled species. We also analyze policy alternatives designed to encourage forest cover and natural landscapes and reduce urban expansion. Although these policy scenarios modify baseline land-use patterns, they do not reverse powerful underlying trends. Policy interventions need to be aggressive to significantly alter underlying land-use change trends and shift the trajectory of ecosystem service provision. PMID:24799685

  2. Projected land-use change impacts on ecosystem services in the United States

    PubMed Central

    Lawler, Joshua J.; Lewis, David J.; Nelson, Erik; Plantinga, Andrew J.; Polasky, Stephen; Withey, John C.; Helmers, David P.; Martinuzzi, Sebastián; Pennington, Derric; Radeloff, Volker C.

    2014-01-01

    Providing food, timber, energy, housing, and other goods and services, while maintaining ecosystem functions and biodiversity that underpin their sustainable supply, is one of the great challenges of our time. Understanding the drivers of land-use change and how policies can alter land-use change will be critical to meeting this challenge. Here we project land-use change in the contiguous United States to 2051 under two plausible baseline trajectories of economic conditions to illustrate how differences in underlying market forces can have large impacts on land-use with cascading effects on ecosystem services and wildlife habitat. We project a large increase in croplands (28.2 million ha) under a scenario with high crop demand mirroring conditions starting in 2007, compared with a loss of cropland (11.2 million ha) mirroring conditions in the 1990s. Projected land-use changes result in increases in carbon storage, timber production, food production from increased yields, and >10% decreases in habitat for 25% of modeled species. We also analyze policy alternatives designed to encourage forest cover and natural landscapes and reduce urban expansion. Although these policy scenarios modify baseline land-use patterns, they do not reverse powerful underlying trends. Policy interventions need to be aggressive to significantly alter underlying land-use change trends and shift the trajectory of ecosystem service provision. PMID:24799685

  3. Understanding of Grassland Ecosystems under Climate Change and Economic Development Pressures in the Mongolia Plateau

    NASA Astrophysics Data System (ADS)

    Qi, J.; Chen, J.; Shan, P.; Pan, X.; Wei, Y.; Wang, M.; Xin, X.

    2011-12-01

    The land use and land cover change, especially in the form of grassland degradation, in the Mongolian Plateau, exhibited a unique spatio-temporal pattern that is a characteristic of a mixed stress from economic development and climate change of the region. The social dimension of the region played a key role in shaping the landscape and land use change, including the cultural clashes with economic development, conflicts between indigenous people and business ventures, and exogenous international influences. Various research projects have been conducted in the region to focus on physical degradation of grasslands and/or on economic development but there is a lack of understanding how the social and economic dimensions interact with grassland ecosystems and changes. In this talk, a synthesis report was made based on the most recent workshop held in Hohhot, Inner Mongolia, of China, that specifically focused on climate change and grassland ecosystems. The report analyzed the degree of grassland degradation, its climate and social drivers, and coupling nature of economic development and conservation of traditional grassland values. The goal is to fully understand the socio-ecological-economic interactions that together shape the trajectory of the grassland ecosystems in the Mongolia Plateau.

  4. Increases in Growing Season Length and Changes in Precipitation at Six Different Arctic and Subarctic Ecosystems from 1906-Present

    NASA Astrophysics Data System (ADS)

    Culler, L. E.; Finger, R.; Plane, E.; Ayres, M.; Virginia, R. A.

    2015-12-01

    Ecological dynamics across the Arctic are responding to rapid changes in climate. As a whole, the Arctic has warmed at approximately twice the rate of the rest of the world, but changes in temperature and precipitation experienced at regional and local scales are most important for coupled human-natural systems. In addition, biologically-relevant climate indices are necessary for quantifying ecological responses of terrestrial and aquatic systems to varying climate. We compared climatic changes at six different Arctic and sub-Arctic locations, including two in Greenland (Kangerlussuaq, Sisimiut), one in Sweden (Abisko), and three in Alaska (Barrow, Nome, Fairbanks). We amassed weather data (daily temperature and precipitation), dating as far back as 1906, from public-access databases and used these data to calculate indices such as length of growing season, growing season degree days (GDD), and growing season precipitation. Annual GDD increased at all locations (average of 13% increase in GDD since 1980), but especially in western Greenland (16 and 37% in Kangerlussuaq and Sisimiut, respectively). Changes in growing season precipitation were more variable, with only Barrow, AK and Abisko, Sweden experiencing increased precipitation. All other sites experienced stable or slightly declining precipitation. Increasing temperatures and relatively stable precipitation translates to increased evapotranspiration potential, which influences soil moisture, lake depth, vegetation, carbon emissions, and fire susceptibility. Understanding local and regional trends in temperature and precipitation can help explain observed phenological changes and other processes at population, community, and ecosystem levels. In addition, identification of locations most susceptible to future change will allow scientists to closely monitor their ecological dynamics, anticipate changes in coupled human-natural systems, and consider adaptation plans for the most rapidly changing systems.

  5. Planetary Habitability and Rapid Environmental Change: The Biological Perspective

    NASA Astrophysics Data System (ADS)

    Schulze-Makuch, D.; Fairen, A.; Irwin, L.

    2012-12-01

    Environmental conditions can change drastically and rapidly during the natural history of a planetary body. We have detailed evidence of these dramatic events from Venus, Earth, Mars, and Titan. Most of these occurrences seem to be triggered by astronomical events such as asteroid impacts or supernova explosions; others are triggered by the planet or moon itself (e.g., supervolcano eruptions). The associated question is always how these events affect the habitability of a planet, particularly the origin and presence of life. Under what conditions would such a drastic event be so catastrophic that it would prohibit the origin of life or be so devastating to existing organisms, that life would not be able to recover and be all but extinguished from a planet? Under what conditions would such an event be positive for the evolution of life, for example spurring life via mass extinctions and associated vacant habitats to the invention of new body plans and higher complexity? Here, we provide insights of what we can learn from the natural history of our own planet, which experienced many environmental disasters and abrupt climate changes, from the impact event that created the Moon to the extinction of the dinosaurs. We apply these insights to other planetary bodies and the question about the presence of life. One example is Mars, which underwent drastic environmental changes at the end of the Noachian period. Assuming that microbial life became established on Mars, could it have survived, perhaps by retreating to environmental niches? Life just starting out would have certainly been more vulnerable to extinction. But how far would it have to have evolved to be more resistant to potential extinction events? Would it have to be global in distribution to survive? Another example is Venus. Should Venus be seen as an example where life, which possibly arose in the first few hundred million years when the planet was still in the habitable zone, would have had no chance to

  6. Seismic paleoceanography and the stratigraphic signature of rapid climate changes

    NASA Astrophysics Data System (ADS)

    Berne, Serge; Sierro, Francisco Javier

    2015-04-01

    The term "seismic paleoceanography" was introduced in 2004 by R. Schneider, a former Chair of Images, during the EC-funded « Promess » project, for highlighting the importance of seismic data in paleoceanographic reconstructions during this particular project. The interest of seismic stratigraphy prior to drilling operations, such as those of the IODP, has long been recognized, and became a pre-requisite for the submission of scientific proposals. However, this kind of expedition generally relies on relatively low resolution, multi-channel seismic data where only the impact of major climate changes can be visualized. In contrast, a large proportion of the Images community, more familiar with the Marion Dufresne, mainly considers seismic data as a support for selecting the best coring sites. The large amount of shallow cores, borehole and seismic (at various frequencies) data available in the Gulf of Lions allows us to illustrate the importance of very high- and ultra high- resolution seismic data for tracking the signature of rapid climate changes. The flooding events associated to "Bond Cycles" (bundles of several Dansgaard-Oeschger cycles) during MIS 3- MIS 2, are an example of the interesting feedbacks between seismic interpretation and high-resolution paleoceanography. These events where first identified in the Gulf of Lions through the multi-proxy analysis of cores retrieved at site PRGL1-4 (Sierro et al., 2009). In return, the re-examination of seismic data allows us to identify a series of corresponding seismic bounding surfaces (characterized by toplap and onlap terminations) along the continental slope. In terms of seismic amplitudes, the seismic surface associated to the transition between Heinrich Stadial 4 and Interstadial 8 appears as the most pronounced event during the entire MIS3-MIS2, suggesting that the magnitude of the associated sea-level change was the most important of this interval. Even more subtle events, such as the Melt Water Pulse 19

  7. Ecosystem change and stability over multiple decades in the Swedish subarctic: complex processes and multiple drivers

    PubMed Central

    Callaghan, Terry V; Jonasson, Christer; Thierfelder, Tomas; Yang, Zhenlin; Hedenås, Henrik; Johansson, Margareta; Molau, Ulf; Van Bogaert, Rik; Michelsen, Anders; Olofsson, Johan; Gwynn-Jones, Dylan; Bokhorst, Stef; Phoenix, Gareth; Bjerke, Jarle W.; Tømmervik, Hans; Christensen, Torben R.; Hanna, Edward; Koller, Eva K.; Sloan, Victoria L.

    2013-01-01

    The subarctic environment of northernmost Sweden has changed over the past century, particularly elements of climate and cryosphere. This paper presents a unique geo-referenced record of environmental and ecosystem observations from the area since 1913. Abiotic changes have been substantial. Vegetation changes include not only increases in growth and range extension but also counterintuitive decreases, and stability: all three possible responses. Changes in species composition within the major plant communities have ranged between almost no changes to almost a 50 per cent increase in the number of species. Changes in plant species abundance also vary with particularly large increases in trees and shrubs (up to 600%). There has been an increase in abundance of aspen and large changes in other plant communities responding to wetland area increases resulting from permafrost thaw. Populations of herbivores have responded to varying management practices and climate regimes, particularly changing snow conditions. While it is difficult to generalize and scale-up the site-specific changes in ecosystems, this very site-specificity, combined with projections of change, is of immediate relevance to local stakeholders who need to adapt to new opportunities and to respond to challenges. Furthermore, the relatively small area and its unique datasets are a microcosm of the complexity of Arctic landscapes in transition that remains to be documented. PMID:23836792

  8. Estimating California ecosystem carbon change using process model and land cover disturbance data: 1951-2000

    USGS Publications Warehouse

    Liu, J.; Vogelmann, J.E.; Zhu, Z.; Key, C.H.; Sleeter, B.M.; Price, D.T.; Chen, J.M.; Cochrane, M.A.; Eidenshink, J.C.; Howard, S.M.; Bliss, N.B.; Jiang, H.

    2011-01-01

    Land use change, natural disturbance, and climate change directly alter ecosystem productivity and carbon stock level. The estimation of ecosystem carbon dynamics depends on the quality of land cover change data and the effectiveness of the ecosystem models that represent the vegetation growth processes and disturbance effects. We used the Integrated Biosphere Simulator (IBIS) and a set of 30- to 60-m resolution fire and land cover change data to examine the carbon changes of California's forests, shrublands, and grasslands. Simulation results indicate that during 1951-2000, the net primary productivity (NPP) increased by 7%, from 72.2 to 77.1TgCyr-1 (1 teragram=1012g), mainly due to CO2 fertilization, since the climate hardly changed during this period. Similarly, heterotrophic respiration increased by 5%, from 69.4 to 73.1TgCyr-1, mainly due to increased forest soil carbon and temperature. Net ecosystem production (NEP) was highly variable in the 50-year period but on average equalled 3.0TgCyr-1 (total of 149TgC). As with NEP, the net biome production (NBP) was also highly variable but averaged -0.55TgCyr-1 (total of -27.3TgC) because NBP in the 1980s was very low (-5.34TgCyr-1). During the study period, a total of 126Tg carbon were removed by logging and land use change, and 50Tg carbon were directly removed by wildland fires. For carbon pools, the estimated total living upper canopy (tree) biomass decreased from 928 to 834TgC, and the understory (including shrub and grass) biomass increased from 59 to 63TgC. Soil carbon and dead biomass carbon increased from 1136 to 1197TgC. Our analyses suggest that both natural and human processes have significant influence on the carbon change in California. During 1951-2000, climate interannual variability was the key driving force for the large interannual changes of ecosystem carbon source and sink at the state level, while logging and fire were the dominant driving forces for carbon balances in several specific

  9. Rapid change in the thermal tolerance of a tropical lizard.

    PubMed

    Leal, Manuel; Gunderson, Alex R

    2012-12-01

    The predominant view is that the thermal physiology of tropical ectotherms, including lizards, is not labile over ecological timescales. We used the recent introduction (∼35 years ago) of the Puerto Rican lizard Anolis cristatellus to Miami, Florida, to test this thermal rigidity hypothesis. We measured lower (critical thermal minimum [CT(min)]) and upper (critical thermal maximum [CT(max)]) thermal tolerances and found that the introduced population tolerates significantly colder temperatures (by ∼3°C) than does the Puerto Rican source population; however, CT(max) did not differ. These results mirror the thermal regimes experienced by each population: Miami reaches colder ambient temperatures than Puerto Rico, but maximum ambient temperatures are similar. The differences in CT(min) were observed even though lizards from both sites experienced nearly identical conditions for 49 days before CT(min) measurement. Our results demonstrate that changes in thermal tolerance occurred relatively rapidly (∼35 generations), which strongly suggests that the thermal physiology of tropical lizards is more labile than previously proposed. PMID:23149405

  10. Responses of Tundra Ecosystems to Environmental Change: Observational and Experimental Results

    NASA Astrophysics Data System (ADS)

    Henry, G. H.

    2004-05-01

    Evidence of environmental changes due to human-enhanced climate warming continues to accumulate from polar regions. Responses in tundra and taiga ecosystems to climate changes have been variable because of the wide range in process response rates, from metabolic processes to adjustments in ecosystem carbon balance, and the variability in environmental settings across local to regional scales. For example, strong increases in rates of plant growth and changes in species composition and abundance have been observed in parts of the Low Arctic, but very little change has been measured in high arctic tundra. A dramatic increase in the cover of deciduous shrubs in areas of the western North American Arctic is predicted to result in positive feedbacks to soil temperature, through increased surface roughness and snow depth, and to atmospheric heating by reducing albedo. Increased shrub cover has also been found in long-term experimental warming studies conducted throughout the tundra biome as part of the International Tundra Experiment (ITEX). Warming is also affecting the carbon balance of tundra and taiga, which hold 25% of the soil carbon of global terrestrial ecosystems. However, trajectories of these changes are largely unknown for most northern systems, and differ because of initial conditions of the carbon and nutrient economy. Over the longer-term, the positive increases in plant growth may be constrained by negative feedbacks to nutrient cycling, as increases in C:N ratios of plant litter slow the release of nitrogen to soils. However, nitrogen availability has been shown to increase in response to short-term warming. In this presentation, I will review the responses of tundra ecosystems to climate variability and change, both through observational and experimental studies.

  11. Changes in the forest ecosystems in areas impacted by aridization in south-western Romania

    PubMed Central

    2014-01-01

    Background In the past few decades, global climate change has accentuated the intensification of aridization in South-Western Romania, with direct and indirect consequences on the quality of forest ecosystems. In addition to qualitative deterioration, the quantitative changes brought about by intensive anthropic deforestation have created the conditions for a decline in the size of forest areas on vast tracts of land. The paper aims to analyze the qualitative and quantitative changes in the forest ecosystems in South-Western Romania, changes due to the synergic context of the global climate changes and the anthropic pressures of the past three decades. In order to capture the evolution of aridization in the study area, specific aridization indexes have been calculated, such as the De Martonne index and the UNEP aridity index. 1990 and 2011 satellite images have been used in order to quantify the qualitative changes. Results The results obtained indicated that, in the past two decades, the quality of the biomass declined as a result of the increase in the climatic aridity conditions (De Martonne si UNEP aridity index, indicating in the last decades, annual values under 15 mm/°C, and under 0.5 mm/mm, that means that the values situated under these thresholds, describe arid and semi-arid climate conditions). Also, the uncontrolled logging across vast surfaces caused the loss of forest ecosystems by 7% in the overall study area, during the last three decades. Conclusions The severe effects of aridization meant, first of all, a significant decline in the quality of the ecosystem services supplied by forests. In the absence of viable actions to correct the present situation, the extremely undesirable consequences of an ecological and social nature will arise in the near future. PMID:24393389

  12. Impacts of climate-driven changes on coastal lagoon ecosystem and related good and services

    NASA Astrophysics Data System (ADS)

    Solidoro, Cosimo; Libralato, Simone; Melaku Canu, Donata; Cossarini, Gianpiero; Giorgi, FIlippo

    2014-05-01

    Effects of IPCC climate change scenarios on a temperate coastal lagoon ecosystem, the lagoon of Venice (Italy), along with goods and services provided by this ecosystem are assessed though a downscaling experiment linking regional atmospheric model to local hydrodynamical, biogeochemical, ecosystem and target species population dynamic models. Simulations of spatio-temporal dynamics of biogeochemical properties provide evidence of significant impacts of climate change. Under both the A2 and B2 scenarios we observe a modification of the seasonal precipitation pattern which affects the timing of nutrient inputs to the lagoon and causes a reduction in plankton productivity. Simulations indicate that this changes propagate -along the food web through a multi-path cascade and that overall ecosystem good and services resulting from climatic scenarios significantly differ depending on the dynamics of the extremes (yearly maximum) values. Changes in the nutrient load maximum discharge (scenario A2) favors primary producers that have higher maximum values (peaks) that propagate up in the food web to groups directly related to the grazing food chain. Conversely, small modifications of the timing of the nutrient peaks (as in B2 scenario) implies less exploitation of nutrients by primary producers due to temperature limitations and the enhancement of the groups in the food web that are more related to detritus-based food chain. This implies significant differences on on fisheries landings in future scenarios, even assuming same fishing effort.. Ecological indicators highlighted also divergent changes in food web biodiversity and complexity in the two future scenarios. Simulations also shows that economic activity directly related to target species, such as clam aquaculture activity will suffer , and point to the need for management policies to mitigate the adverse effects of climate change.

  13. Salinization of Freshwater-Dependent Coastal Ecosystems: Understanding Landscapes in Transition Along the Leading Edge of Climate Change

    NASA Astrophysics Data System (ADS)

    Emanuel, R. E.; Bernhardt, E. S.; Ardón, M.; Wright, J. P.; BenDor, T.; Bhattachan, A.

    2015-12-01

    Climate change is transforming the outer edge of the Southern US coastal plain. Lower-lying parts of this region, characterized by extensive freshwater-dependent ecosystems, will be largely inundated by gradual sea level rise by the end of this century. In the interim, however, ocean waters are already penetrating and influencing freshwater-dependent coastal landscapes due to a combination of human and natural factors. This landward movement of salinity from the coast onto the coastal plain or "saltwater intrusion" is a critical water resource issue representing the leading edge of climate change for many coastal areas. The salinization of surface waters and adjacent lands has implications for crop and timber yields in managed ecosystems, ecosystem carbon sequestration in unmanaged ecosystems, and degradation of coastal water quality due to extraction of soil nutrients by seasalts. With this in mind, we seek to understand more broadly how vulnerability of coastal landscapes to saltwater intrusion shapes and is shaped by both natural and anthropogenic processes. We present a novel framework that couples intensive, in situ monitoring of hydrological and ecological conditions with a geospatial saltwater intrusion vulnerability index (SIVI). We discuss application of this framework to the Albemarle-Pamlico region of coastal North Carolina, where we are learning how climate, natural landscape structure, and human activities interact to mediate or exacerbate the vulnerability of freshwater-dependent lands to saltwater intrusion. We discuss the involvement of stakeholders and local knowledge in the research process as well. This work advances understanding of vulnerability to climate change in coastal regions by moving beyond simple inundation models to gain a more sophisticated understanding of the human and natural processes influencing salinization of surface waters and adjacent lands. As the Albemarle-Pamlico and similar regions worldwide transform in response to and

  14. Ecological ethics in captivity: balancing values and responsibilities in zoo and aquarium research under rapid global change.

    PubMed

    Minteer, Ben A; Collins, James P

    2013-01-01

    Ethical obligations to animals in conservation research and management are manifold and often conflicting. Animal welfare concerns often clash with the ethical imperative to understand and conserve a population or ecosystem through research and management intervention. The accelerating pace and impact of global environmental change, especially climate change, complicates our understanding of these obligations. One example is the blurring of the distinction between ex situ (zoo- and aquarium-based) conservation and in situ (field-based) approaches as zoos and aquariums become more active in field conservation work and as researchers and managers consider more intensive interventions in wild populations and ecosystems to meet key conservation goals. These shifts, in turn, have consequences for our traditional understanding of the ethics of wildlife research and management, including our relative weighting of animal welfare and conservation commitments across rapidly evolving ex situ and in situ contexts. Although this changing landscape in many ways supports the increased use of captive wildlife in conservation-relevant research, it raises significant ethical concerns about human intervention in populations and ecosystems, including the proper role of zoos and aquariums as centers for animal research and conservation in the coming decades. Working through these concerns requires a pragmatic approach to ethical analysis, one that is able to make trade-offs among the many goods at stake (e.g., animal welfare, species viability, and ecological integrity) as we strive to protect species from further decline and extinction in this century. PMID:23904531

  15. Quantifying the effect of trend, fluctuation, and extreme event of climate change on ecosystem productivity.

    PubMed

    Liu, Yupeng; Yu, Deyong; Su, Yun; Hao, Ruifang

    2014-12-01

    Climate change comprises three fractions of trend, fluctuation, and extreme event. Assessing the effect of climate change on terrestrial ecosystem requires an understanding of the action mechanism of these fractions, respectively. This study examined 11 years of remotely sensed-derived net primary productivity (NPP) to identify the impacts of the trend and fluctuation of climate change as well as extremely low temperatures caused by a freezing disaster on ecosystem productivity in Hunan province, China. The partial least squares regression model was used to evaluate the contributions of temperature, precipitation, and photosynthetically active radiation (PAR) to NPP variation. A climatic signal decomposition and contribution assessment model was proposed to decompose climate factors into trend and fluctuation components. Then, we quantitatively evaluated the contributions of each component of climatic factors to NPP variation. The results indicated that the total contribution of the temperature, precipitation, and PAR to NPP variation from 2001 to 2011 in Hunan province is 85 %, and individual contributions of the temperature, precipitation, and PAR to NPP variation are 44 % (including 34 % trend contribution and 10 % fluctuation contribution), 5 % (including 4 % trend contribution and 1 % fluctuation contribution), and 36 % (including 30 % trend contribution and 6 % fluctuation contribution), respectively. The contributions of temperature fluctuation-driven NPP were higher in the north and lower in the south, and the contributions of precipitation trend-driven NPP and PAR fluctuation-driven NPP are higher in the west and lower in the east. As an instance of occasionally triggered disturbance in 2008, extremely low temperatures and a freezing disaster produced an abrupt decrease of NPP in forest and grass ecosystems. These results prove that the climatic trend change brought about great impacts on ecosystem productivity and that climatic fluctuations and

  16. Climate change impacts utilizing regional models for agriculture, hydrology and natural ecosystems

    NASA Astrophysics Data System (ADS)

    Kafatos, M.; Asrar, G. R.; El-Askary, H. M.; Hatzopoulos, N.; Kim, J.; Kim, S.; Medvigy, D.; Prasad, A. K.; Smith, E.; Stack, D. H.; Tremback, C.; Walko, R. L.

    2012-12-01

    Climate change impacts the entire Earth but with crucial and often catastrophic impacts at local and regional levels. Extreme phenomena such as fires, dust storms, droughts and other natural hazards present immediate risks and challenges. Such phenomena will become more extreme as climate change and anthropogenic activities accelerate in the future. We describe a major project funded by NIFA (Grant # 2011-67004-30224), under the joint NSF-DOE-USDA Earth System Models (EaSM) program, to investigate the impacts of climate variability and change on the agricultural and natural (i.e. rangeland) ecosystems in the Southwest USA using a combination of historical and present observations together with climate, and ecosystem models, both in hind-cast and forecast modes. The applicability of the methodology to other regions is relevant (for similar geographic regions as well as other parts of the world with different agriculture and ecosystems) and should advance the state of knowledge for regional impacts of climate change. A combination of multi-model global climate projections from the decadal predictability simulations, to downscale dynamically these projections using three regional climate models, combined with remote sensing MODIS and other data, in order to obtain high-resolution climate data that can be used with hydrological and ecosystem models for impacts analysis, is described in this presentation. Such analysis is needed to assess the future risks and potential impacts of projected changes on these natural and managed ecosystems. The results from our analysis can be used by scientists to assist extended communities to determine agricultural coping strategies, and is, therefore, of interest to wide communities of stakeholders. In future work we will be including surface hydrologic modeling and water resources, extend modeling to higher resolutions and include significantly more crops and geographical regions with different weather and climate conditions

  17. Using Rapid-Response Scenario-Building Methodology for Climate Change Adaptation Planning

    NASA Astrophysics Data System (ADS)

    Ludwig, K. A.; Stoepler, T. M.; Schuster, R.

    2015-12-01

    Rapid-response scenario-building methodology can be modified to develop scenarios for slow-onset disasters associated with climate change such as drought. Results of a collaboration between the Department of the Interior (DOI) Strategic Sciences Group (SSG) and the Southwest Colorado Social-Ecological Climate Resilience Project are presented in which SSG scenario-building methods were revised and applied to climate change adaptation planning in Colorado's Gunnison Basin, United States. The SSG provides the DOI with the capacity to rapidly assemble multidisciplinary teams of experts to develop scenarios of the potential environmental, social, and economic cascading consequences of environmental crises, and to analyze these chains to determine actionable intervention points. By design, the SSG responds to acute events of a relatively defined duration. As a capacity-building exercise, the SSG explored how its scenario-building methodology could be applied to outlining the cascading consequences of slow-onset events related to climate change. SSG staff facilitated two workshops to analyze the impacts of drought, wildfire, and insect outbreak in the sagebrush and spruce-fir ecosystems. Participants included local land managers, natural and social scientists, ranchers, and other stakeholders. Key findings were: 1) scenario framing must be adjusted to accommodate the multiple, synergistic components and longer time frames of slow-onset events; 2) the development of slow-onset event scenarios is likely influenced by participants having had more time to consider potential consequences, relative to acute events; 3) participants who are from the affected area may have a more vested interest in the outcome and/or may be able to directly implement interventions.

  18. Estimating nocturnal ecosystem respiration from the vertical turbulent flux and change in storage of CO2

    SciTech Connect

    Gu, Lianhong; Van Gorsel, Eva; Leuning, Ray; Delpierre, Nicolas; Black, Andy; Chen, Baozhang; Munger, J. William; Wofsy, Steve; Aubinet, M.

    2009-11-01

    Micrometeorological measurements of nighttime ecosystem respiration can be systematically biased when stable atmospheric conditions lead to drainage flows associated with decoupling of air flow above and within plant canopies. The associated horizontal and vertical advective fluxes cannot be measured using instrumentation on the single towers typically used at micrometeorological sites. A common approach to minimize bias is to use a threshold in friction velocity, u*, to exclude periods when advection is assumed to be important, but this is problematic in situations when in-canopy flows are decoupled from the flow above. Using data from 25 flux stations in a wide variety of forest ecosystems globally, we examine the generality of a novel approach to estimating nocturnal respiration developed by van Gorsel et al. (van Gorsel, E., Leuning, R., Cleugh, H.A., Keith, H., Suni, T., 2007. Nocturnal carbon efflux: reconciliation of eddy covariance and chamber measurements using an alternative to the u*-threshold filtering technique. Tellus 59B, 397 403, Tellus, 59B, 307-403). The approach is based on the assumption that advection is small relative to the vertical turbulent flux (FC) and change in storage (FS) of CO2 in the few hours after sundown. The sum of FC and FS reach a maximum during this period which is used to derive a temperature response function for ecosystem respiration. Measured hourly soil temperatures are then used with this function to estimate respiration RRmax. The new approach yielded excellent agreement with (1) independent measurements using respiration chambers, (2) with estimates using ecosystem light-response curves of Fc + Fs extrapolated to zero light, RLRC, and (3) with a detailed process-based forest ecosystem model, Rcast. At most sites respiration rates estimated using the u*-filter, Rust, were smaller than RRmax and RLRC. Agreement of our approach with independent measurements indicates that RRmax provides an excellent estimate of nighttime

  19. Response of Peat-forming Ecosystems of the Western Antarctic Peninsula to Recent Climate Change

    NASA Astrophysics Data System (ADS)

    Tardona, M.; Beilman, D.; Yu, Z.; Loisel, J.

    2014-12-01

    Amplified warming and related environmental changes in the high latitudes have a complex geographic pattern, with the Western Antarctic Peninsula experiencing one of the fastest rates of recent warming globally. To better understand the response of terrestrial Antarctic ecosystems to polar change, we applied a paleoscience approach to organic soil profiles from 13 aerobic peatbank ecosystems on 7 islands along the peninsula from 67.6 to 64.2°S. Peatbank ecosystem ages were obtained by Radiocarbon measurements of organic matter from the base of these profiles and cluster in three groups: older than 1000 years old (as old as 2750 years old), 400-500 years old, and younger than 65 years with fixed bomb-spike carbon. Three of these peatbank profiles were studied in detail, and show growth rates over the last 65 years of ~2.5 mm yr-1. This rate is faster than those observed during previous periods but is similar to other recent nearby studies that report recent growth rates of ~2.6 mm yr-1. Organic carbon storage ranged from 6.1 to 21.3 kgC m-2. Values of moss bank organic matter δ13C show progressively more depleted δ13C values; in which depletion increases 3.0‰ over recent decades. Overall increase in source-independent discrimination is 1.7‰, consistent with published records from other locations and an increase in photosynthetic activity at the regional scale. Source-independent discrimination displays substantial variations corresponding negatively to variation of organic matter C:N values. Our results imply several recent changes in Antarctic peat forming ecosystem processes including formation of new moss banks, increased accumulation rates, and high variability in source-independent discrimination. These changes are complex but affected by contemporary climate changes of the region including increasing temperatures over the past century.

  20. Multiple stressors, nonlinear effects and the implications of climate change impacts on marine coastal ecosystems.

    PubMed

    Hewitt, Judi E; Ellis, Joanne I; Thrush, Simon F

    2016-08-01

    Global climate change will undoubtedly be a pressure on coastal marine ecosystems, affecting not only species distributions and physiology but also ecosystem functioning. In the coastal zone, the environmental variables that may drive ecological responses to climate change include temperature, wave energy, upwelling events and freshwater inputs, and all act and interact at a variety of spatial and temporal scales. To date, we have a poor understanding of how climate-related environmental changes may affect coastal marine ecosystems or which environmental variables are likely to produce priority effects. Here we use time series data (17 years) of coastal benthic macrofauna to investigate responses to a range of climate-influenced variables including sea-surface temperature, southern oscillation indices (SOI, Z4), wind-wave exposure, freshwater inputs and rainfall. We investigate responses from the abundances of individual species to abundances of functional traits and test whether species that are near the edge of their tolerance to another stressor (in this case sedimentation) may exhibit stronger responses. The responses we observed were all nonlinear and some exhibited thresholds. While temperature was most frequently an important predictor, wave exposure and ENSO-related variables were also frequently important and most ecological variables responded to interactions between environmental variables. There were also indications that species sensitive to another stressor responded more strongly to weaker climate-related environmental change at the stressed site than the unstressed site. The observed interactions between climate variables, effects on key species or functional traits, and synergistic effects of additional anthropogenic stressors have important implications for understanding and predicting the ecological consequences of climate change to coastal ecosystems. PMID:26648483

  1. Ecosystem composition changes over the past millennium: model simulations and comparison with paleoecological observations

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Rollinson, C.; Dietze, M.; McLachlan, J. S.; Poulter, B.; Quaife, T. L.; Raiho, A.; Ricciuto, D. M.; Schaefer, K. M.; Steinkamp, J.; Moore, D. J.

    2015-12-01

    Over multi-decadal to multi-centennial timescales, ecosystem function and carbon storage is largely influenced by vegetation composition. The predictability of ecosystem responses to climate change thus depends on the understanding of long-term community dynamics. Our study aims to quantify the influence of the most relevant ecological factors that control plant distribution and abundance, in contemporary terrestrial biosphere models and in paleo-records, and constrain the model processes and parameters with paleoecological data. We simulated vegetation changes at 6 sites in the northeastern United States over the past 1160 years using 7 terrestrial biosphere models and variations (CLM4.5-CN, ED2, ED2-LU, JULES-TRIFFID, LINKAGES, LPJ-GUESS, LPJ-wsl) driven by common paleoclimatic drivers. We examined plant growth, recruitment, and mortality (including other carbon turnover) of the plant functional types (PFTs) in the models, attributed the responses to three major factors (climate, competition, and disturbance), and estimated the relative effect of each factor. We assessed the model responses against plant-community theories (bioclimatic limits, niche difference, temporal variation and storage effect, and disturbance). We found that vegetation composition were sensitive to realized niche differences (e.g. differential growth response) among PFTs. Because many models assume unlimited dispersal and sometimes recruitment, the "storage effect" constantly affects community composition. Fire was important in determining the ecosystem composition, yet the vegetation to fire feedback was weak in the models. We also found that vegetation-composition changes in the simulations were driven to a much greater degree by growth as opposed to by turnover/mortality, when compared with those in paleoecological records. Our work suggest that 1) for forecasting slow changes in vegetation composition, we can use paleo-data to better quantify the realized niches of PFTs and associated

  2. A century of climate and ecosystem change in Western Montana: What do temperature trends portend?

    USGS Publications Warehouse

    Pederson, G.T.; Graumlich, L.J.; Fagre, D.B.; Kipfer, T.; Muhlfeld, C.C.

    2010-01-01

    The physical science linking human-induced increases in greenhouse gasses to the warming of the global climate system is well established, but the implications of this warming for ecosystem processes and services at regional scales is still poorly understood. Thus, the objectives of this work were to: (1) describe rates of change in temperature averages and extremes for western Montana, a region containing sensitive resources and ecosystems, (2) investigate associations between Montana temperature change to hemispheric and global temperature change, (3) provide climate analysis tools for land and resource managers responsible for researching and maintaining renewable resources, habitat, and threatened/endangered species and (4) integrate our findings into a more general assessment of climate impacts on ecosystem processes and services over the past century. Over 100 years of daily and monthly temperature data collected in western Montana, USA are analyzed for long-term changes in seasonal averages and daily extremes. In particular, variability and trends in temperature above or below ecologically and socially meaningful thresholds within this region (e.g., -17.8??C (0??F), 0??C (32??F), and 32.2??C (90??F)) are assessed. The daily temperature time series reveal extremely cold days (??? -17.8??C) terminate on average 20 days earlier and decline in number, whereas extremely hot days (???32??C) show a three-fold increase in number and a 24-day increase in seasonal window during which they occur. Results show that regionally important thresholds have been exceeded, the most recent of which include the timing and number of the 0??C freeze/thaw temperatures during spring and fall. Finally, we close with a discussion on the implications for Montana's ecosystems. Special attention is given to critical processes that respond non-linearly as temperatures exceed critical thresholds, and have positive feedbacks that amplify the changes. ?? Springer Science + Business Media B

  3. Changes in ecosystem structure related to the type and extent of woody cover alter carbon dynamics and surface energy exchange in central Texas ecosystems.

    NASA Astrophysics Data System (ADS)

    Litvak, M. E.; Heilman, J.; McInnes, K.; Owens, K.; Kjelgaard, J.; Thijs, A.

    2006-12-01

    Rangeland ecosystems account for almost two thirds the total land area in Texas. Over the past century, heavy livestock grazing and fire suppression coupled with changes in climate have facilitated the expansion of woody species into rangelands throughout the state. Based in part on the assumption that woody species use more water than their herbaceous counterparts, land managers have used a variety of techniques to reduce tree and shrub abundance to combat the loss of forage for cattle. As a result, the structure of rangelands in Texas is complex, characterized by woody vegetation that is patchy in distribution, and continually changing between grassland, savanna and woodland. Despite the large areal extent of Texas rangelands, very little is known about how the observed changes in ecosystem structure impact carbon cycle dynamics and surface energy exchange. To reduce these uncertainties, we explored explicit relationships between structure and function in these ecosystems by comparing tower-based measurements of carbon and water vapor exchange made simultaneously from July 2004-Dec 2005 across three representative land covers in central Texas: open grassland, savanna with 30% Ashe juniper and honey mesquite cover, and closed canopy woodland. Here we report our findings on what impact the type and pattern of woody plant cover has on biological controls and patterns of carbon sequestration, evapotranspiration, and sensitivity to precipitation pulses. Monthly measurements of leaf level gas exchange, soil respiration rates, herbaceous net ecosystem exchange, and sap flow measurements on dominant woody species were used to augment eddy covariance estimates of ecosystem-atmosphere exchange. The addition of woody species significantly increased carbon sequestration in these ecosystems. Net ecosystem production from July 05-Jun 05 in the grassland, savanna and forest ecosystems was -14 g C m-2, -413 g C m-2, -450 g C m-2, respectively. Evapotranspiration was less

  4. Reviews on land use change induced effects on regional hydrological ecosystem services for integrated water resources management

    NASA Astrophysics Data System (ADS)

    Jin, Gui; Wang, Pei; Zhao, Tao; Bai, Yuping; Zhao, Chunhong; Chen, Dongdong

    This paper proposed to provide valuable information for integrated water resources management through evaluating the research on the interaction mechanism among land use changes, regional hydrological ecosystem services and human well-being. Firstly, the driving mechanism of land use and land cover changes was introduced in this paper. Secondly, the overview of the interaction mechanism among land use and land cover changes, regional hydrological ecosystem services and human well-being was given. Based on the meta-analysis, land use changes have a profound influence on regional hydrological ecosystem services, and the variation of hydrological ecosystem could benefit or impair human well-being. Finally, two suggestions were emphasized for managers or policy makers for the future integrated water resources management: (1) Proper land use makes for the water resource management; (2) Blindly pursuing the provisioning services weakens other services of hydrological ecosystem.

  5. Global methane and nitrous oxide emissions from terrestrial ecosystems due to multiple environmental changes

    DOE PAGESBeta

    Tian, Hanqin; Chen, Guangsheng; Lu, Chaoqun; Xu, Xiaofeng; Ren, Wei; Zhang, Bowen; Banger, Kamaljit; Tao, Bo; Pan, Shufen; Chu, Mingliang; et al

    2015-03-16

    Greenhouse gas (GHG)-induced climate change is among the most pressing sustainability challenges facing humanity today, posing serious risks for ecosystem health. Methane (CH4) and nitrous oxide (N2O) are the two most important GHGs after carbon dioxide (CO2), but their regional and global budgets are not well known. In this paper, we applied a process-based coupled biogeochemical model to concurrently estimate the magnitude and spatial and temporal patterns of CH4 and N2O fluxes as driven by multiple environmental changes, including climate variability, rising atmospheric CO2, increasing nitrogen deposition, tropospheric ozone pollution, land use change, and nitrogen fertilizer use.

  6. A Coupled SD and CLUE-S Model for Exploring the Impact of Land Use Change on Ecosystem Service Value: A Case Study in Baoshan District, Shanghai, China.

    PubMed

    Wu, Meng; Ren, Xiangyu; Che, Yue; Yang, Kai

    2015-08-01

    Most of the cities in developing countries are experiencing rapid urbanization. Land use change driven by urban sprawl, population growth, and intensified socio-economic activities have led to a steep decline of ecosystem service value (ESV) in rapid urbanization areas, and decision-makers often ignore some valuable ecosystem service functions and values in land use planning. In this paper, we attempt to build a modeling framework which integrated System Dynamics model with Conversion of Land Use and its Effects at Small Extent model to simulate the dynamics of ESV of landscape and explore the potential impacts of land use change on ESV. We take Baoshan district of Shanghai as an example which is a fast urbanization area of metropolitan in China. The results of the study indicate that: (1) The integrated methodology can improve the characterization and presentation of the dynamics of ESV, which may give insight into understanding the possible impacts of land use change on ESV and provide information for land use planning. (2) Land use polices can affect the magnitude and location of ESV both directly and indirectly. Land use changes tend to weaken and simplify ecosystem service functions and values of landscape at urban rural fringe where land use change is more intensive. (3) The application of the methodology has proved that the integration of currently existing models within a single modeling framework could be a beneficial exploration, and should be encouraged and enhanced in the future research on the changing dynamics of ESV due to the complexity of ecosystem services and land use system. PMID:25924787

  7. A Coupled SD and CLUE-S Model for Exploring the Impact of Land Use Change on Ecosystem Service Value: A Case Study in Baoshan District, Shanghai, China

    NASA Astrophysics Data System (ADS)

    Wu, Meng; Ren, Xiangyu; Che, Yue; Yang, Kai

    2015-08-01

    Most of the cities in developing countries are experiencing rapid urbanization. Land use change driven by urban sprawl, population growth, and intensified socio-economic activities have led to a steep decline of ecosystem service value (ESV) in rapid urbanization areas, and decision-makers often ignore some valuable ecosystem service functions and values in land use planning. In this paper, we attempt to build a modeling framework which integrated System Dynamics model with Conversion of Land Use and its Effects at Small Extent model to simulate the dynamics of ESV of landscape and explore the potential impacts of land use change on ESV. We take Baoshan district of Shanghai as an example which is a fast urbanization area of metropolitan in China. The results of the study indicate that: (1) The integrated methodology can improve the characterization and presentation of the dynamics of ESV, which may give insight into understanding the possible impacts of land use change on ESV and provide information for land use planning. (2) Land use polices can affect the magnitude and location of ESV both directly and indirectly. Land use changes tend to weaken and simplify ecosystem service functions and values of landscape at urban rural fringe where land use change is more intensive. (3) The application of the methodology has proved that the integration of currently existing models within a single modeling framework could be a beneficial exploration, and should be encouraged and enhanced in the future research on the changing dynamics of ESV due to the complexity of ecosystem services and land use system.

  8. Climate change, coral reef ecosystems, and management options for marine protected areas.

    PubMed

    Keller, Brian D; Gleason, Daniel F; McLeod, Elizabeth; Woodley, Christa M; Airamé, Satie; Causey, Billy D; Friedlander, Alan M; Grober-Dunsmore, Rikki; Johnson, Johanna E; Miller, Steven L; Steneck, Robert S

    2009-12-01

    Marine protected areas (MPAs) provide place-based management of marine ecosystems through various degrees and types of protective actions. Habitats such as coral reefs are especially susceptible to degradation resulting from climate change, as evidenced by mass bleaching events over the past two decades. Marine ecosystems are being altered by direct effects of climate change including ocean warming, ocean acidification, rising sea level, changing circulation patterns, increasing severity of storms, and changing freshwater influxes. As impacts of climate change strengthen they may exacerbate effects of existing stressors and require new or modified management approaches; MPA networks are generally accepted as an improvement over individual MPAs to address multiple threats to the marine environment. While MPA networks are considered a potentially effective management approach for conserving marine biodiversity, they should be established in conjunction with other management strategies, such as fisheries regulations and reductions of nutrients and other forms of land-based pollution. Information about interactions between climate change and more "traditional" stressors is limited. MPA managers are faced with high levels of uncertainty about likely outcomes of management actions because climate change impacts have strong interactions with existing stressors, such as land-based sources of pollution, overfishing and destructive fishing practices, invasive species, and diseases. Management options include ameliorating existing stressors, protecting potentially resilient areas, developing networks of MPAs, and integrating climate change into MPA planning, management, and evaluation. PMID:19636605

  9. Climate Change, Coral Reef Ecosystems, and Management Options for Marine Protected Areas

    NASA Astrophysics Data System (ADS)

    Keller, Brian D.; Gleason, Daniel F.; McLeod, Elizabeth; Woodley, Christa M.; Airamé, Satie; Causey, Billy D.; Friedlander, Alan M.; Grober-Dunsmore, Rikki; Johnson, Johanna E.; Miller, Steven L.; Steneck, Robert S.

    2009-12-01

    Marine protected areas (MPAs) provide place-based management of marine ecosystems through various degrees and types of protective actions. Habitats such as coral reefs are especially susceptible to degradation resulting from climate change, as evidenced by mass bleaching events over the past two decades. Marine ecosystems are being altered by direct effects of climate change including ocean warming, ocean acidification, rising sea level, changing circulation patterns, increasing severity of storms, and changing freshwater influxes. As impacts of climate change strengthen they may exacerbate effects of existing stressors and require new or modified management approaches; MPA networks are generally accepted as an improvement over individual MPAs to address multiple threats to the marine environment. While MPA networks are considered a potentially effective management approach for conserving marine biodiversity, they should be established in conjunction with other management strategies, such as fisheries regulations and reductions of nutrients and other forms of land-based pollution. Information about interactions between climate change and more “traditional” stressors is limited. MPA managers are faced with high levels of uncertainty about likely outcomes of management actions because climate change impacts have strong interactions with existing stressors, such as land-based sources of pollution, overfishing and destructive fishing practices, invasive species, and diseases. Management options include ameliorating existing stressors, protecting potentially resilient areas, developing networks of MPAs, and integrating climate change into MPA planning, management, and evaluation.

  10. Innovation in regulation of rapidly changing health markets.

    PubMed

    Bloom, Gerald; Henson, Spencer; Peters, David H

    2014-01-01

    The rapid evolution and spread of health markets across low and middle-income countries (LMICs) has contributed to a significant increase in the availability of health-related goods and services around the world. The support institutions needed to regulate these markets have lagged behind, with regulatory systems that are weak and under-resourced. This paper explores the key issues associated with regulation of health markets in LMICs, and the different goals of regulation, namely quality and safety of care, value for money, social agreement over fair access and financing, and accountability. Licensing, price controls, and other traditional approaches to the regulation of markets for health products and services have played an important role, but they have been of questionable effectiveness in ensuring safety and efficacy at the point of the user in LMICs. The paper proposes a health market systems conceptual framework, using the value chain for the production, distribution and retail of health goods and services, to examine regulation of health markets in the LMIC context. We conclude by exploring the changing context going forwards, laying out implications for future heath market regulation. We argue that the case for new approaches to the regulation of markets for health products and services in LMICs is compelling. Although traditional "command and control" approaches will have a place in the toolkit of regulators, a broader bundle of approaches is needed that is adapted to the national and market-level context of particular LMICs. The implication is that it is not possible to apply standard or single interventions across countries, as approaches proven to work well in one context will not necessarily work well elsewhere. PMID:24961602

  11. Optical Defocus Rapidly Changes Choroidal Thickness in Schoolchildren

    PubMed Central

    Liu, Manli; Lee, Roger Pak Kin; Sun, Yuan; Zhang, Ting; Lam, Chuen; Liu, Quan; To, Chi Ho

    2016-01-01

    The current study aimed to examine the short-term choroidal response to optical defocus in schoolchildren. Myopic schoolchildren aged 8–16 were randomly allocated to control group (CG), myopic defocus group (MDG) and hyperopic defocus group (HDG) (n = 17 per group). Children in MDG and HDG received additional +3D and -3D lenses, respectively, to their full corrections on the right eyes. Full correction was given to their left eyes, and on both eyes in the CG. Axial length (AXL) and subfoveal choroidal thickness (SFChT) were then measured by spectral domain optical coherence tomography. Children wore their group-specific correction for 2 hours after which any existing optical defocus was removed, and subjects wore full corrections for another 2 hours. Both the AXL and SFChT were recorded hourly for 4 hours. The mean refraction of all subjects was -3.41 ± 0.37D (± SEM). SFChT thinned when exposed to hyperopic defocus for 2 hours but less thinning was observed in response to myopic defocus compared to the control group (p < 0.05, two-way ANOVA). Removal of optical defocus significantly decreased SFChT in the MDG and significantly increased SFChT in the HDG after 1 and 2 hours (mean percentage change at 2-hour; control vs. hyperopic defocus vs. myopic defocus; -0.33 ± 0.59% vs. 3.04 ± 0.60% vs. -1.34 ± 0.74%, p < 0.01). Our results showed short-term exposure to myopic defocus induced relative choroidal thickening while hyperopic defocus led to choroidal thinning in children. This rapid and reversible choroidal response may be an important clinical parameter in gauging retinal response to optical defocus in human myopia. PMID:27537606

  12. Innovation in regulation of rapidly changing health markets

    PubMed Central

    2014-01-01

    The rapid evolution and spread of health markets across low and middle-income countries (LMICs) has contributed to a significant increase in the availability of health-related goods and services around the world. The support institutions needed to regulate these markets have lagged behind, with regulatory systems that are weak and under-resourced. This paper explores the key issues associated with regulation of health markets in LMICs, and the different goals of regulation, namely quality and safety of care, value for money, social agreement over fair access and financing, and accountability. Licensing, price controls, and other traditional approaches to the regulation of markets for health products and services have played an important role, but they have been of questionable effectiveness in ensuring safety and efficacy at the point of the user in LMICs. The paper proposes a health market systems conceptual framework, using the value chain for the production, distribution and retail of health goods and services, to examine regulation of health markets in the LMIC context. We conclude by exploring the changing context going forwards, laying out implications for future heath market regulation. We argue that the case for new approaches to the regulation of markets for health products and services in LMICs is compelling. Although traditional "command and control" approaches will have a place in the toolkit of regulators, a broader bundle of approaches is needed that is adapted to the national and market-level context of particular LMICs. The implication is that it is not possible to apply standard or single interventions across countries, as approaches proven to work well in one context will not necessarily work well elsewhere. PMID:24961602

  13. Implications of agricultural land use change to ecosystem services in the Ganges delta.

    PubMed

    Islam, G M Tarekul; Islam, A K M Saiful; Shopan, Ahsan Azhar; Rahman, Md Munsur; Lázár, Attila N; Mukhopadhyay, Anirban

    2015-09-15

    Ecosystems provide the basis for human civilization and natural capital for green economy and sustainable development. Ecosystem services may range from crops, fish, freshwater to those that are harder to see such as erosion regulation, carbon sequestration, and pest control. Land use changes have been identified as the main sources of coastal and marine pollution in Bangladesh. This paper explores the temporal variation of agricultural land use change and its implications with ecosystem services in the Ganges delta. With time agricultural lands have been decreased and wetlands have been increased at a very high rate mainly due to the growing popularity of saltwater shrimp farming. In a span of 28 years, the agricultural lands have been reduced by approximately 50%, while the wetlands have been increased by over 500%. A large portion (nearly 40%) of the study area is covered by the Sundarbans which remained almost constant which can be attributed to the strict regulatory intervention to preserve the Sundarbans. The settlement & others land use type has also been increased to nearly 5%. There is a gradual uptrend of shrimp and fish production in the study area. The findings suggest that there are significant linkages between agricultural land use change and ecosystem services in the Ganges delta in Bangladesh. The continuous decline of agricultural land (due to salinization) and an increase of wetland have been attributed to the conversion of agricultural land into shrimp farming in the study area. Such land use change requires significant capital, therefore, only investors and wealthier land owners can get the higher profit from the land conversion while the poor people is left with the environmental consequences that affect their long-term lives and livelihood. An environmental management plan is proposed for sustainable land use in the Ganges delta in Bangladesh. PMID:25516384

  14. Small Changes in Climate Can Profoundly Alter the Dynamics and Ecosystem Services of Tropical Crater Lakes

    PubMed Central

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

    2014-01-01

    African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have largely focused on the massive Great Rift Valley lakes. Our objective was to evaluate how recent climate change has altered the functioning and services of smaller tropical lakes, which are far more abundant on the landscape. Based on a paired analysis of 20 years of high-resolution water column data and a paleolimnological record from a small crater lake in western Uganda, we present evidence that even a modest warming of the air (∼0.9°C increase over 20 years) and changes in the timing and intensity of rainfall can have significant consequences on the dynamics of this common tropical lake type. For example, we observed a significant nonlinear increase (R2adj = 0.23, e.d.f. = 7, p<0.0001) in thermal stability over the past 20 years. This resulted in the expansion of anoxic waters and consequent deterioration of fish habitat and appears to have abated primary production; processes that may impair ecosystem services for a vulnerable human population. This study on a system representative of small tropical crater lakes highlights the far-reaching effects of global climatic change on tropical waters. Increased research efforts into tropical aquatic ecosystem health and the development of sound management practices are necessary in order to strengthen adaptive capabilities in tropical regions. PMID:24497954

  15. Changing sources and sinks of carbon in boreal ecosystems of Interior Alaska: Current and future perspectives

    NASA Astrophysics Data System (ADS)

    Douglas, T. A.; Jones, M.; Hiemstra, C. A.

    2012-12-01

    Future climate scenarios predict a roughly 5°C increase in mean annual air temperatures for the Alaskan Interior over the next 80 years. Increasing temperatures and greater frequency and severity of climate-induced disturbances such as wildfires will be enough to initiate permafrost degradation in many areas of Alaska, leading to major changes in surface hydrology and ecosystem structure and function. This, in turn, is expected to alter the current inventories of carbon sources and sinks in the region and provide a management challenge for carbon itemization efforts. To assist land managers in adapting and planning for potential changes in Interior Alaska carbon cycling we synthesize information on climate, ecosystem processes, vegetation, and soil, permafrost, and hydrologic regimes in Interior Alaska. Our goal is to provide an assessment of the current and likely future regime of Interior Alaska carbon sources and sinks. For our carbon assessment we: 1) synthesize the most recent results from numerous studies on the carbon cycle with a focus on research from the Alaskan boreal biome, 2) assemble a summary of estimates of carbon sources in soil and vegetation in Interior Alaska, 3) categorize carbon sources and sinks for predominant Interior Alaska ecosystems, and 4) identify expected changes in sources and sinks with climate change and human activities. This information is used to provide recommendations on potential actions land managers can take to minimize carbon export from the boreal forest. Though the results from our project are geared primarily toward policy makers and land managers we also provide recommendations for filling research gaps that currently present uncertainty in our understanding of the carbon cycle in boreal forest ecosystems of Interior Alaska.

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

    PubMed

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

    2014-01-01

    African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have largely focused on the massive Great Rift Valley lakes. Our objective was to evaluate how recent climate change has altered the functioning and services of smaller tropical lakes, which are far more abundant on the landscape. Based on a paired analysis of 20 years of high-resolution water column data and a paleolimnological record from a small crater lake in western Uganda, we present evidence that even a modest warming of the air (∼0.9°C increase over 20 years) and changes in the timing and intensity of rainfall can have significant consequences on the dynamics of this common tropical lake type. For example, we observed a significant nonlinear increase (R(2) adj  = 0.23, e.d.f. = 7, p<0.0001) in thermal stability over the past 20 years. This resulted in the expansion of anoxic waters and consequent deterioration of fish habitat and appears to have abated primary production; processes that may impair ecosystem services for a vulnerable human population. This study on a system representative of small tropical crater lakes highlights the far-reaching effects of global climatic change on tropical waters. Increased research efforts into tropical aquatic ecosystem health and the development of sound management practices are necessary in order to strengthen adaptive capabilities in tropical regions. PMID:24497954

  17. Environmental impact assessment and monetary ecosystem service valuation of an ecosystem under different future environmental change and management scenarios; a case study of a Scots pine forest.

    PubMed

    Schaubroeck, Thomas; Deckmyn, Gaby; Giot, Olivier; Campioli, Matteo; Vanpoucke, Charlotte; Verheyen, Kris; Rugani, Benedetto; Achten, Wouter; Verbeeck, Hans; Dewulf, Jo; Muys, Bart

    2016-05-15

    For a sustainable future, we must sustainably manage not only the human/industrial system but also ecosystems. To achieve the latter goal, we need to predict the responses of ecosystems and their provided services to management practices under changing environmental conditions via ecosystem models and use tools to compare the estimated provided services between the different scenarios. However, scientific articles have covered a limited amount of estimated ecosystem services and have used tools to aggregate services that contain a significant amount of subjective aspects and that represent the final result in a non-tangible unit such as 'points'. To resolve these matters, this study quantifies the environmental impact (on human health, natural systems and natural resources) in physical units and uses an ecosystem service valuation based on monetary values (including ecosystem disservices with associated negative monetary values). More specifically, the paper also focuses on the assessment of ecosystem services related to pollutant removal/generation flows, accounting for the inflow of eutrophying nitrogen (N) when assessing the effect of N leached to groundwater. Regarding water use/provisioning, evapotranspiration is alternatively considered a disservice because it implies a loss of (potential) groundwater. These approaches and improvements, relevant to all ecosystems, are demonstrated using a Scots pine stand from 2010 to 2089 for a combination of three environmental change and three management scenarios. The environmental change scenarios considered interannual climate variability trends and included alterations in temperature, precipitation, nitrogen deposition, wind speed, Particulate matter (PM) concentration and CO2 concentration. The addressed flows/ecosystem services, including disservices, are as follows: particulate matter removal, freshwater loss, CO2 sequestration, wood production, NOx emissions, NH3 uptake and nitrogen pollution/removal. The monetary

  18. Ecosystem Structure Changes in the Turkish Seas as a Response to Overfishing

    NASA Astrophysics Data System (ADS)

    Gazihan Akoglu, Ayse; Salihoglu, Baris; Akoglu, Ekin; Kideys, Ahmet E.

    2013-04-01

    Human population in Turkey has grown more than five-fold since its establishment in 1923 and more than 73 million people are currently living in the country. Turkey is surrounded by partially connected seas (the Black Sea, the Sea of Marmara, the Aegean Sea and the Mediterranean Sea) each of which has significantly different productivity levels and ecosystem characteristics. Increasing human population with its growing socio-economic needs has generated an intensive fishing pressure on the fish stocks in its exclusive economic zone. Fishing grounds in the surrounding seas were exploited with different fishing intensities depending upon their productivity level and catch rates. Hence, the responses of these different ecosystems to overfishing have been realized differently. In this study, changes of the ecosystem structures in the Turkish Seas were comparatively investigated by ecosystem indices such as Marine Trophic Index (MTI), Fishing in Balance (FiB) and Primary Production Required (PPR) to assess the degree of sustainability of the fish stocks for future generations.

  19. Understanding ecosystems' sub-daily water and carbon flux changes during dry-down events

    NASA Astrophysics Data System (ADS)

    Nelson, Jacob; Jung, Martin; Carvalhais, Nuno; Migliavacca, Mirco; Reichstein, Markus

    2016-04-01

    Sub-daily water and carbon flux patterns give important and sometimes overlooked information about ecosystem processes and land-atmosphere feedbacks. While models often perform well down to daily timescales, they can be uncertain with respect to the diurnal courses, especially during dry-down events where the fraction of T to ET is shifting. We analyzed events from multiple locations for unique pattern changes that were robust across sites. Of particular interest were the divergence of water and carbon fluxes during high radiation periods, which indicates changes in water use efficiency as drought conditions intensified. The validity of attributing the signatures to ecosystem transitions such as changes in phenology, switches in soil evaporation vs transpiration dominance, and physiological stress were evaluated by comparing to site specific sap flow, soil moisture, and remote sensing data. Going forward, these findings can be used to further understand ecosystem physiology under drought conditions, and can also be used to partition of water fluxes and better constrain future models.

  20. GLOBEC: Global Ocean Ecosystems Dynamics: A component of the US Global Change Research Program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    GLOBEC (GLOBal ocean ECosystems dynamics) is a research initiative proposed by the oceanographic and fisheries communities to address the question of how changes in global environment are expected to affect the abundance and production of animals in the sea. The approach to this problem is to develop a fundamental understanding of the mechanisms that determine both the abundance of key marine animal populations and their variances in space and time. The assumption is that the physical environment is a major contributor to patterns of abundance and production of marine animals, in large part because the planktonic life stages typical of most marine animals are intrinsically at the mercy of the fluid motions of the medium in which they live. Consequently, the authors reason that a logical approach to predicting the potential impact of a globally changing environment is to understand how the physical environment, both directly and indirectly, contributes to animal abundance and its variability in marine ecosystems. The plans for this coordinated study of of the potential impact of global change on ocean ecosystems dynamics are discussed.

  1. Ecosystem services in Mediterranean river basin: climate change impact on water provisioning and erosion control.

    PubMed

    Bangash, Rubab F; Passuello, Ana; Sanchez-Canales, María; Terrado, Marta; López, Alfredo; Elorza, F Javier; Ziv, Guy; Acuña, Vicenç; Schuhmacher, Marta

    2013-08-01

    The Mediterranean basin is considered one of the most vulnerable regions of the world to climate change and such changes impact the capacity of ecosystems to provide goods and services to human society. The predicted future scenarios for this region present an increased frequency of floods and extended droughts, especially at the Iberian Peninsula. This paper evaluates the impacts of climate change on the water provisioning and erosion control services in the densely populated Mediterranean Llobregat river basin of. The assessment of ecosystem services and their mapping at the basin scale identify the current pressures on the river basin including the source area in the Pyrenees Mountains. Drinking water provisioning is expected to decrease between 3 and 49%, while total hydropower production will decrease between 5 and 43%. Erosion control will be reduced by up to 23%, indicating that costs for dredging the reservoirs as well as for treating drinking water will also increase. Based on these data, the concept for an appropriate quantification and related spatial visualization of ecosystem service is elaborated and discussed. PMID:23660520

  2. Changes in ecosystem carbon and nitrogen in a loblolly pine plantation over the first 18 years

    SciTech Connect

    Johnson, Dale W.; Todd Jr, Donald E; Tolbert, Virginia R

    2003-09-01

    Eighteen years after the establishment of a loblolly pine (Pinus taeda L.) plantation, ecosystem C content had approximately tripled (from 54 to 161 Mg C ha{sup -1}) primarily because of increases in tree biomass. Ninety-three percent of the net ecosystem C accumulated in biomass (100 Mg C ha{sup -1}) and 6% of net ecosystem C accumulated in the forest floor (13 Mg C ha{sup -1}). No statistically significant changes in soil C were found. Growth responses to fertilization noted in Year 4 were no longer statistically significant in Year 18. Nitrogen accumulation in aboveground biomass and forest floor were approximately equal (averaging approximately 270 kg N ha{sup -1} each) and could have come from a combination of atmospheric deposition, soil N mineralization, and, in the treated plots, fertilizer input. No statistically significant changes in soil N content were found. The results of this study are similar to those from a previous study in a loblolly pine plantation in South Carolina but contrast with those in nearby deciduous forests where substantial changes in soil C and N over similar time periods have been noted.

  3. New insights from coral growth band studies in an era of rapid environmental change

    NASA Astrophysics Data System (ADS)

    Lough, Janice M.; Cooper, Timothy F.

    2011-10-01

    The rapid formation of calcium carbonate coral skeletons (calcification) fuelled by the coral-algal symbiosis is the backbone of tropical coral reef ecosystems. However, the efficacy of calcification is measurably influenced by the sea's physico-chemical environment, which is changing rapidly. Warming oceans have already led to increased frequency and severity of coral bleaching, and ocean acidification has a demonstrable potential to cause reduced rates of calcification. There is now general agreement that ocean warming and acidification are attributable to human activities increasing greenhouse gas concentrations in the atmosphere, and the large part of the extra carbon dioxide (the main greenhouse gas) that is absorbed by oceans. Certain massive corals provide historical perspectives on calcification through the presence of dateable annual density banding patterns. Each band is a page in an environmental archive that reveals past responses of growth (linear extension, skeletal density and calcification rate) and provides a basis for prediction of future of coral growth. A second major line of research focuses on the measurement of various geochemical tracers incorporated into the growth bands, allowing the reconstruction of past marine climate conditions (i.e. palaeoclimatology). Here, we focus on the structural properties of the annual density bands themselves (viz. density; linear extension), exploring their utility in providing both perspectives on the past and pointers to the future of calcification on coral reefs. We conclude that these types of coral growth records, though relatively neglected in recent years compared to the geochemical studies, remain immensely valuable aids to unravelling the consequences of anthropogenic climate change on coral reefs. Moreover, an understanding of coral growth processes is an essential pre-requisite for proper interpretation of studies of geochemical tracers in corals.

  4. Late Permian marine ecosystem collapse began in deeper waters: evidence from brachiopod diversity and body size changes.

    PubMed

    He, W-H; Shi, G R; Twitchett, R J; Zhang, Y; Zhang, K-X; Song, H-J; Yue, M-L; Wu, S-B; Wu, H-T; Yang, T-L; Xiao, Y-F

    2015-03-01

    Analysis of Permian-Triassic brachiopod diversity and body size changes from different water depths spanning the continental shelf to basinal facies in South China provides insights into the process of environmental deterioration. Comparison of the temporal changes of brachiopod diversity between deepwater and shallow-water facies demonstrates that deepwater brachiopods disappeared earlier than shallow-water brachiopods. This indicates that high environmental stress commenced first in deepwater settings and later extended to shallow waters. This environmental stress is attributed to major volcanic eruptions, which first led to formation of a stratified ocean and a chemocline in the outer shelf and deeper water environments, causing the disappearance of deep marine benthos including brachiopods. The chemocline then rapidly migrated upward and extended to shallow waters, causing widespread mass extinction of shallow marine benthos. We predict that the spatial and temporal patterns of earlier onset of disappearance/extinction and ecological crisis in deeper water ecosystems will be recorded during other episodes of rapid global warming. PMID:25412754

  5. Shallow Groundwater and Brine Processes in Antarctica: Linking Seasonal and Interannual Changes in Active Layer Hydrology to Ecosystem Change and Thermokarst Formation

    NASA Astrophysics Data System (ADS)

    Levy, J. S.

    2015-12-01

    We report on measurements of soil hydrological and thermal properties from the McMurdo Dry Valleys of Antarctica (MDV), and relate them to changes in the spatial patterns of shallow groundwater flow (water tracks), landscape subsidence (thermokarst), and microbial and invertebrate ecosystem response. We show that shallow groundwater in the MDV is primarily derived from snowfall and seasonal ground ice melt, but is evaporatively concentrated during the summer flow period to produce saline to hypersaline active layer solutions. Multi-year profiles of soil temperature and soil moisture indicate that water track flow is largely limited to the duration of active layer conditions (~2 months) and that water track discharge is characterized by an early season pulse as ground ice melts, and a late season pulse as solutions flowing downslope accumulate at the base of the water tracks. Evaporative concentration of water track fluids, coupled with soil salt dissolution, and/or cation exchange reactions, result in enrichment of water track fluids in chloride and sulfate salts (depending on local soil chemistry) such that initially fresh snowmelt becomes saline to hypersaline over several km of groundwater flow. These brines shape soil ecosystems in the MDV by controlling salinity-dependent habitat suitability for invertebrates and microbial organisms. We show that these soil salts and shallow groundwater solutions accumulate in local depressions to form ponds, and that where these ponds are located above buried ice, the presence of salts leads to expansion of the basins to form large thermokarst depressions. Because water tracks are primarily snow-fed, and are moderated by shallow groundwater processes, they represent a component of the Antarctic hydrological system that is likely to respond rapidly to regional changes in temperature and precipitation, altering Antarctic terrestrial ecosystems, carbon budgets, and ground ice distribution.

  6. Diets of aquatic birds reflect changes in the Lake Huron ecosystem

    USGS Publications Warehouse

    Hebert, Craig E.; Weseloh, D.V. Chip; Idrissi, Abode; Arts, Michael T.; Roseman, Edward F.

    2009-01-01

    Human activities have affected the Lake Huron ecosystem, in part, through alterations in the structure and function of its food webs. Insights into the nature of food web change and its ecological ramifications can be obtained through the monitoring of high trophic level predators such as aquatic birds. Often, food web change involves alterations in the relative abundance of constituent species and/or the introduction of new species (exotic invaders). Diet composition of aquatic birds is influenced, in part, by relative prey availability and therefore is a sensitive measure of food web structure. Using bird diet data to make inferences regarding food web change requires consistent measures of diet composition through time. This can be accomplished by measuring stable chemical and/or biochemical “ecological tracers” in archived avian samples. Such tracers provide insights into pathways of energy and nutrient transfer. In this study, we examine the utility of two groups of naturally-occurring intrinsic tracers (stable isotopes and fatty acids) to provide such information in a predatory seabird, the herring gull (Larus argentatus). Retrospective stable nitrogen and carbon isotope analysis of archived herring gull eggs identified declines in gull trophic position and shifts in food sources in Lake Huron over the last 25 years and changes in gull diet composition were inferred from egg fatty acid patterns. These independent groups of ecological tracers provided corroborating evidence of dietary change in this high trophic level predator. Gull dietary shifts were related to declines in prey fish abundance which suggests large-scale alterations to the Lake Huron ecosystem. Dietary shifts in herring gulls may be contributing to reductions in resources available for egg formation. Further research is required to evaluate how changes in resource availability may affect population sustainability in herring gulls and other waterbird species. Long-term biological monitoring

  7. Analysis of Future Streamflow Regimes under Global Change Scenarios in Central Chile for Ecosystem Sustainability

    NASA Astrophysics Data System (ADS)

    Henriquez Dole, L. E.; Gironas, J. A.; Vicuna, S.

    2015-12-01

    Given the critical role of the streamflow regime for ecosystem sustainability, modeling long term effects of climate change and land use change on streamflow is important to predict possible impacts in stream ecosystems. Because flow duration curves are largely used to characterize the streamflow regime and define indices of ecosystem health, they were used to represent and analyze in this study the stream regime in the Maipo River Basin in Central Chile. Water and Environmental Assessment and Planning (WEAP) model and the Plant Growth Model (PGM) were used to simulate water distribution, consumption in rural areas and stream flows on a weekly basis. Historical data (1990-2014), future land use scenarios (2030/2050) and climate change scenarios were included in the process. Historical data show a declining trend in flows mainly by unprecedented climatic conditions, increasing interest among users on future streamflow scenarios. In the future, under an expected decline in water availability coupled with changes in crop water demand, water users will be forced to adapt by changing water allocation rules. Such adaptation actions would in turns affect the streamflow regime. Future scenarios for streamflow regime show dramatic changes in water availability and temporal distribution. Annual weekly mean flows can reduce in 19% in the worst scenario and increase in 3.3% in the best of them, and variability in streamflow increases nearly 90% in all scenarios under evaluation. The occurrence of maximum and minimum monthly flows changes, as June instead of July becomes the driest month, and December instead of January becomes the month with maximum flows. Overall, results show that under future scenarios streamflow is affected and altered by water allocation rules to satisfy water demands, and thus decisions will need to consider the streamflow regime (and habitat) in order to be sustainable.

  8. Two takes on the ecosystem impacts of climate change and fishing: Comparing a size-based and a species-based ecosystem model in the central North Pacific

    NASA Astrophysics Data System (ADS)

    Woodworth-Jefcoats, Phoebe A.; Polovina, Jeffrey J.; Howell, Evan A.; Blanchard, Julia L.

    2015-11-01

    We compare two ecosystem model projections of 21st century climate change and fishing impacts in the central North Pacific. Both a species-based and a size-based ecosystem modeling approach are examined. While both models project a decline in biomass across all sizes in response to climate change and a decline in large fish biomass in response to increased fishing mortality, the models vary significantly in their handling of climate and fishing scenarios. For example, based on the same climate forcing the species-based model projects a 15% decline in catch by the end of the century while the size-based model projects a 30% decline. Disparities in the models' output highlight the limitations of each approach by showing the influence model structure can have on model output. The aspects of bottom-up change to which each model is most sensitive appear linked to model structure, as does the propagation of interannual variability through the food web and the relative impact of combined top-down and bottom-up change. Incorporating integrated size- and species-based ecosystem modeling approaches into future ensemble studies may help separate the influence of model structure from robust projections of ecosystem change.

  9. Conversion of woodlands changes soil related ecosystem services in Subsaharan Africa

    NASA Astrophysics Data System (ADS)

    Groengroeft, Alexander; Landschreiber, Lars; Luther-Mosebach, Jona; Masamba, Wellington; Zimmermann, Ibo; Eschenbach, Annette

    2015-04-01

    In remote areas of Subsaharan Africa, growing population, changes in consumption patterns and increasing global influences are leading to a strong pressure on the land resources. Smallholders convert woodlands by fire, grazing and clearing in different intensities thus changing soil properties and their ecosystem functioning. As the extraction of ecosystem services forms the basis of local wellbeing for many communities, the role of soils in providing ecosystem services is of high importance. Since 2010, "The Future Okavango" project investigates the quantification of ecosystem functions and services at four core research sites along the Okavango river basin (Angola, Namibia, Botswana, see http://www.future-okavango.org/). These research sites have an extent of 100 km2 each. Within our subproject the soil functions underlying ecosystem services are studied: The amount and spatial variation of soil nutrient reserves in woodland and their changes by land use activities, the water storage function as a basis for plant growth, and their effect on groundwater recharge and the carbon storage function. The scientific framework consists of four major parts including soil survey and mapping, lab analysis, field measurements and modeling approaches on different scales. A detailed soil survey leads to a measure of the spatial distribution, extent and heterogeneity of soil types for each research site. For generalization purposes, geomorphological and pedological characteristics are merged to derive landscape units. These landscape units have been overlaid by recent land use types to stratify the research site for subsequent soil sampling. On the basis of field and laboratory analysis, spatial distribution of soil properties as well as boundaries between neighboring landscape units are derived. The parameters analysed describe properties according to grain size distribution, organic carbon content, saturated and unsaturated hydraulic conductivity as well as pore space

  10. Ecosystem management mitigates climate change induced vegetation shifts in West Africa

    NASA Astrophysics Data System (ADS)

    Scheiter, S.; Savadogo, P.

    2013-12-01

    Savannas serve as benefit to livelihood for many people in the tropics and sub-tropics and welfare of people strongly depends on goods and services that savanna ecosystems provide, such as food production, livestock production, fuel wool, species richness and climate stabilization. Yet, the flow of these ecosystem services is strongly influenced by climate change and land use. Due to the large proportion of the Earth's land surface covered by savannas, changes in the dynamics and structure of savanna vegetation may not only influence the conditions for the local population, but may also have strong impacts on the climate system and global biogeochemical cycles. In this study, we use a dynamic vegetation model, the aDGVM, to explore how climate and land use interact to influence vegetation dynamics and the distribution of west African savannas under ambient and future environmental conditions. More specifically, we investigate fire management, wood cutting and grazing, land use activities often applied in savannas. We show that under future conditions and in the absence of land use, large savanna areas could shift towards a more wood dominated vegetation state due to CO2 fertilization effects, increases in water use efficiency and decreases in fire activity. However, land use has the potential to maintain desired vegetation states that ensure the flux of important ecosystem services even under future conditions. The model projects that ecosystem management can compensate climate change impacts on vegetation and delay or avoid critical biome shifts. This study highlights the impacts of land use and management on vegetation dynamics and the future distribution of savannas and the necessity to include land use into assessments of the future vegetation state.

  11. Effects of climate change on the delivery of soil-mediated ecosystem services within the primary sector in temperate ecosystems: a review and New Zealand case study.

    PubMed

    Orwin, Kate H; Stevenson, Bryan A; Smaill, Simeon J; Kirschbaum, Miko U F; Dickie, Ian A; Clothier, Brent E; Garrett, Loretta G; van der Weerden, Tony J; Beare, Michael H; Curtin, Denis; de Klein, Cecile A M; Dodd, Michael B; Gentile, Roberta; Hedley, Carolyn; Mullan, Brett; Shepherd, Mark; Wakelin, Steven A; Bell, Nigel; Bowatte, Saman; Davis, Murray R; Dominati, Estelle; O'Callaghan, Maureen; Parfitt, Roger L; Thomas, Steve M

    2015-08-01

    Future human well-being under climate change depends on the ongoing delivery of food, fibre and wood from the land-based primary sector. The ability to deliver these provisioning services depends on soil-based ecosystem services (e.g. carbon, nutrient and water cycling and storage), yet we lack an in-depth understanding of the likely response of soil-based ecosystem services to climate change. We review the current knowledge on this topic for temperate ecosystems, focusing on mechanisms that are likely to underpin differences in climate change responses between four primary sector systems: cropping, intensive grazing, extensive grazing and plantation forestry. We then illustrate how our findings can be applied to assess service delivery under climate change in a specific region, using New Zealand as an example system. Differences in the climate change responses of carbon and nutrient-related services between systems will largely be driven by whether they are reliant on externally added or internally cycled nutrients, the extent to which plant communities could influence responses, and variation in vulnerability to erosion. The ability of soils to regulate water under climate change will mostly be driven by changes in rainfall, but can be influenced by different primary sector systems' vulnerability to soil water repellency and differences in evapotranspiration rates. These changes in regulating services resulted in different potentials for increased biomass production across systems, with intensively managed systems being the most likely to benefit from climate change. Quantitative prediction of net effects of climate change on soil ecosystem services remains a challenge, in part due to knowledge gaps, but also due to the complex interactions between different aspects of climate change. Despite this challenge, it is critical to gain the information required to make such predictions as robust as possible given the fundamental role of soils in supporting human well

  12. Mechanistic models as a transferable framework for projecting effects of habitat change on production and delivery of ecosystem services

    EPA Science Inventory

    Drawing a link between habitat change and the production and delivery of ecosystem services is a priority in coastal estuarine ecosystems. Mechanistic modeling tools are highly functional for exploring this link because they allow for the synthesis of multiple ecological and beh...

  13. Potential effects of climate change on freshwater ecosystems of the New England/Mid-Atlantic Region

    USGS Publications Warehouse

    Moore, M.V.; Pace, M.L.; Mather, J.R.; Murdoch, Peter S.; Howarth, R.W.; Folt, C.L.; Chen, C.-Y.; Hemond, Harold F.; Flebbe, P.A.; Driscoll, C.T.

    1997-01-01

    Numerous freshwater ecosystems, dense concentrations of humans along the eastern seaboard, extensive forests and a history of intensive land use distinguish the New England/Mid-Atlantic Region. Human population densities are forecast to increase in portions of the region at the same time that climate is expected to be changing. Consequently, the effects of humans and climatic change are likely to affect freshwater ecosystems within the region interactively. The general climate, at present, is humid continental, and the region receives abundant precipitation. Climatic projections for a 2 ??CO2 atmosphere, however, suggest warmer and drier conditions for much of this region. Annual temperature increases ranging from 3-5??C are projected, with the greatest increases occurring in autumn or winter. According to a water balance model, the projected increase in temperature will result in greater rates of evaporation and evapotranspiration. This could cause a 21 and 31% reduction in annual stream flow in the southern and northern sections of the region, respectively, with greatest reductions occurring in autumn and winter. The amount and duration of snow cover is also projected to decrease across the region, and summer convective thunderstorms are likely to decrease in frequency but increase in intensity. The dual effects of climate change and direct anthropogenic stress will most likely alter hydrological and biogeochemical processes, and, hence, the floral and faunal communities of the region's freshwater ecosystems. For example, the projected increase in evapotranspiration and evaporation could eliminate most bog ecosystems, and increases in water temperature may increase bioaccumulation, and possibly biomagnification, of organic and inorganic contaminants. Not all change may be adverse. For example, a decrease in runoff may reduce the intensity of ongoing estuarine eutrophication, and acidification of aquatic habitats during the spring snowmelt period may be

  14. Critical indirect effects of climate change on sub-Antarctic ecosystem functioning

    PubMed Central

    Louise Allan, E; William Froneman, P; Durgadoo, Jonathan V; McQuaid, Christopher D; Ansorge, Isabelle J; Richoux, Nicole B

    2013-01-01

    Sub-Antarctic islands represent critical breeding habitats for land-based top predators that dominate Southern Ocean food webs. Reproduction and molting incur high energetic demands that are sustained at the sub-Antarctic Prince Edward Islands (PEIs) by both inshore (phytoplankton blooms; “island mass effect”; autochthonous) and offshore (allochthonous) productivity. As the relative contributions of these sustenance pathways are, in turn, affected by oceanographic conditions around the PEIs, we address the consequences of climatically driven changes in the physical environment on this island ecosystem. We show that there has been a measurable long-term shift in the carbon isotope signatures of the benthos inhabiting the shallow shelf region of the PEIs, most likely reflecting a long-term decline in enhanced phytoplankton productivity at the islands in response to a climate-driven shift in the position of the sub-Antarctic Front. Our results indicate that regional climate change has affected the balance between allochthonous and autochthonous productivity at the PEIs. Over the last three decades, inshore-feeding top predators at the islands have shown a marked decrease in their population sizes. Conversely, population sizes of offshore-feeding predators that forage over great distances from the islands have remained stable or increased, with one exception. Population decline of predators that rely heavily on organisms inhabiting the inshore region strongly suggest changes in prey availability, which are likely driven by factors such as fisheries impacts on some prey populations and shifts in competitive interactions among predators. In addition to these local factors, our analysis indicates that changes in prey availability may also result indirectly through regional climate change effects on the islands' marine ecosystem. Most importantly, our results indicate that a fundamental shift in the balance between allochthonous and autochthonous trophic pathways

  15. EnviroAtlas: A Spatially Explicit Tool Combining Climate Change Scenarios with Ecosystem Services Indicators

    NASA Astrophysics Data System (ADS)

    Neale, A. C.; Pickard, B. R.; Megan, M.; Baynes, J.

    2014-12-01

    While discussions of global climate change tend to center on greenhouse gases and sea levelrise, other factors, such as technological developments, land and energy use, economics, and populationgrowth all play a critical role in understanding climate change. There is increasing urgency for methodsto forecast how different sectors, in particular ecosystems and the goods and services they provide, maybe altered as a result of climate change. However, due to their complexity, it is difficult to assess theseecosystem services at a single point in space or time, as they may be influenced by surrounding anddistant patterns of land use and biophysical attributes in addition to climate change. In order to makemeaningful conservation and adaptation choices, specific ecosystem components must be viewed inrelation to future climate information. The US Environmental Protection Agency and its partners, havedeveloped EnviroAtlas, a web-based geospatial tool that allows users to interact with climate changemodeling information while simultaneously providing a range of information and data on differentecosystem goods and services. This can be a useful platform for inquiry about the supply, demand, orbenefits provided by a specific ecosystem service, and to understand the potential impacts to thatecosystem service due to our changing climate. Housing a variety of data in one publicly available toolencourages users to think in new, trans-disciplinary ways that focus on the relationships betweenecosystem services and climate change impacts. By combining many fields of research through this easyto-use interface, the result is a novel tool that is spatially and temporally explicit and enables betterdecision making across multiple sectors. This talk will illustrate how the information presented inEnviroAtlas can be used in research.

  16. The Effects of Land-Use Change on Ecosystem Oxidative Ratio

    NASA Astrophysics Data System (ADS)

    Hockaday, W. C.; Masiello, C. A.; Gallagher, M. E.; Calligan, L.

    2009-12-01

    The carbon budgets of terrestrial ecosystems are typically estimated by tower-based CO2 fluxes and/or ground-based carbon inventories. Carbon uptake by the terrestrial biosphere can also be determined from their influence on the O2 concentration in the atmosphere (Keeling et al., 1996). Relating CO2 uptake to O2 production requires knowledge of the oxidative ratio (OR) of terrestrial ecosystems. Oxidative ratio (OR) is the molar ratio of O2:CO2 exchanged between the biosphere and the atmosphere by the processes of photosynthesis and respiration. Models currently used to apportion anthropogenic CO2 uptake between the land and ocean carbon sinks assume an invariant OR value of 1.10 for the terrestrial biosphere. The assumption of global invariance of OR is likely incorrect as climate and land-use changes alter ecosystem distributions. Moreover, small variations (0.01) in OR produce large global-scale discrepancies (1012 g C) in the estimated size of the terrestrial carbon sink (Randerson et al., 2006). The first SOCCR report estimated that 50% of the North American terrestrial carbon sink can be attributed to woody encroachment on abandoned agricultural lands (CCSP, 2007). The OR of early successional woodlands is poorly constrained and is likely to differ from croplands and forests. Therefore, we hypothesize that woody encroachment could drive a shift in the average OR value of North American ecosystems. The OR of an ecosystem can be measured by simultaneous CO2 and O2 flux measurements. Alternatively, OR can be estimated from the chemical composition of the organic matter in an ecosystem (plant biomass and soil). We used CHNOS combustion elemental analysis and 13C nuclear magnetic resonance to measure OR. We present a preliminary assessment of the OR of cropland, successional woodland, and mature forests at the Kellogg biological station LTER (Hickory Corners, MI, USA). We show significant variation in ecosystem OR, with coniferous forests having the highest OR

  17. Women in Physics in a Rapidly Changing China

    NASA Astrophysics Data System (ADS)

    Wu, Ling-An

    2008-03-01

    Despite the upheavals of the 20th century, physics managed to survive quite well in China, where the first woman president of the American Physical Society was born and bred. During the 1950s as a result of policies that emphasized science and engineering, declared equal rights and equal pay for men and women, and assigned jobs to college graduates irrespective of sex, the number of women in physics increased rapidly, many of whom made notable achievements. Since China's opening up over the last thirty years tremendous changes have taken place, and women now face new opportunities as well as challenges in all aspects of society. Whereas physics used to be regarded as the most elite of the sciences, new fields such as computer science, biotechnology and business are now competing for the best students. Compared with other countries the statistics are not bad; in schools and many physics departments the ratio of women teachers may be 30% or higher, but the numbers drop drastically with rank. Moreover, in some research institutions the ratio of female physicists is actually declining, due to retirement of the older generation and fewer successors. Compulsory retirement for women at an earlier age than for men is also a new factor. Conversely, in recent years the ratio of female graduate students enrolling in physics has increased, even reaching 40% in some universities. However, the reasons for this do not bode well: men are not performing so well as women in entrance exams, while the latter are facing increasing discrimination in employment so they have to seek higher degree qualifications. With the further development of China's economy there will be abundant demand for qualified personnel including women with a physics background. It is imperative to actively support the upcoming generation of women physicists and not lose them in the leaky pipeline. The Chinese Physical Society has taken certain positive steps, such as the recent establishment of the Xie Xi

  18. Researchers, elites, and people in a rapidly changing world.

    PubMed

    Galtung, J

    1983-01-01

    The paper locates the problem of research ethics in a "value-free" science that has made researchers value-blind, insufficiently able to foresee possible negative consequences of what they do, but very able to design strategies to agree to structures that protect them. The intellectual style of a given research community enters as a key variable, and most intellectual styles are seen as ways of making scientific findings less threatening by focusing on data with little interpretation or speculation with little documentation. The famous Wilkes/Gleditsch case in Norway is cited as an example of research that offered both data (obtained from open sources) and interpretation, and was met with disapproval and sentence. The moral problem of value conflicts can best be understood by studying researchers in a social setting, together with elites and people. Only if researchers were on top and truth were the supreme value would the researchers' situation be unproblematic. But philosopher-kings, however omniscient and omnipotent, are rarely benevolent, and the very fact of concentrating so much on top leads to highly unacceptable societies, by demobilizing the rest, turning them into clients. Hence, researchers will live with their problems of being tempted into sins of commission--to pursue destructive knowledge--and sins of omission--not to pursue constructive knowledge, and not to pursue unpleasant truths, not because they want this, but because the structure leads them in that direction. Most researchers probably want security, academic freedom, and relevance, and the problem is this: Elites offer security and relevance, not academic freedom; universities offer security and academic freedom, not relevance; people may offer relevance, but neither security, nor freedom. In a rapidly changing world the interconnections and possibly destructive effects of research far away in space and time have become more evident, at the same time as formerly rich and dominating countries

  19. Ecosystem-based coastal defence in the face of global change.

    PubMed

    Temmerman, Stijn; Meire, Patrick; Bouma, Tjeerd J; Herman, Peter M J; Ysebaert, Tom; De Vriend, Huib J

    2013-12-01

    The risk of flood disasters is increasing for many coastal societies owing to global and regional changes in climate conditions, sea-level rise, land subsidence and sediment supply. At the same time, in many locations, conventional coastal engineering solutions such as sea walls are increasingly challenged by these changes and their maintenance may become unsustainable. We argue that flood protection by ecosystem creation and restoration can provide a more sustainable, cost-effective and ecologically sound alternative to conventional coastal engineering and that, in suitable locations, it should be implemented globally and on a large scale. PMID:24305151

  20. Interactive effects of global and regional change on a coastal ecosystem

    NASA Astrophysics Data System (ADS)

    Reise, Karsten; van Beusekom, Justus E. E.

    2008-03-01

    Shallow waters and lowland meet at the same level in the Wadden Sea, but are separated by walls of coastal defense. What are the prospects of this coastal ecosystem in a warmer world? We focus on tidal waters and inshore sedimentary bottoms, expect nutrient supply from land to dec