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81.
Geoffrey Caron-Lormier David A. Bohan Cathy Hawes Alan Raybould Alison J. Haughton Roger W. Humphry 《Ecological modelling》2009
Predicting ecosystem effects is of crucial importance in a world at threat from natural and human-mediated change. Here we propose an ecologically defensible representation of an ecosystem that facilitates predictive modelling. The representation has its roots in the early trophic and energetic theory of ecosystem dynamics and more recent functional ecology and network theory. Using the arable ecosystem of the UK as an example, we show that the representation allows simplification from the many interacting plant and invertebrate species, typically present in arable fields, to a more tractable number of trophic-functional types. Our compound hypothesis is that “trophic-functional types of plants and invertebrates can be used to explain the structure, diversity and dynamics of arable ecosystems”. The trophic-functional types act as containers for individuals, within an individual-based model, sharing similar trophic behaviour and traits of biomass transformation. Biomass, or energy, flows between the types and this allows the key ecological properties of individual abundance and body mass, at each trophic height, to be followed through simulations. Our preliminary simulation results suggest that the model shows great promise. The simulation output for simple ecosystems, populated with realistic parameter values, is consistent with current laboratory observations and provides exciting indications that it could reproduce field scale phenomena. The model also produces output that links the individual, population and community scales, and may be analysed and tested using community, network (food web) and population dynamic theory. We show that we can include management effects, as perturbations to parameter values, for modelling the effects of change and indicating management responses to change. This model will require robust analysis, testing and validation, and we discuss how we will achieve this in the future. 相似文献
82.
David R. Maidment 《Journal of the American Water Resources Association》2016,52(4):816-824
An Open Water Data Initiative has been established by the federal government to enhance water information sharing across the United States (U.S.) using standardized web services for geospatial and temporal data. In a parallel effort, the National Weather Service has established a new National Water Center on the Tuscaloosa campus of the University of Alabama, at which a new National Water Model starts operations in June 2016, to continually simulate and forecast streamflow discharge throughout the continental U.S. These two developments support the interoperability of streamflow and hydrologic information in time and space from modeled and observed sources through the use of open standards to share water information. 相似文献
83.
Stephanie L. Johnson Timothy Whiteaker David R. Maidment 《Journal of the American Water Resources Association》2009,45(3):654-663
Abstract: A recent study by the Texas Bacteria Total Maximum Daily Load (TMDL) Task Force has recommended the use of load duration curves as a primary tool in calculating bacterial TMDLs. This method is attractive because it effectively integrates flow regimes into TMDL analyses, clearly communicates data through a method that is understandable to the general public, and has been successfully applied in TMDL studies in other states. To ease the creation of load duration curves, an automated load duration curve creation tool called LDCurve has been created within a Microsoft Excel framework. Web services and a webscraper are used to retrieve U.S. Geological Survey streamflow data and Texas Commission on Environmental Quality water quality data. Data are imported to the spreadsheet, combined to create flow and load duration curves, and plotted. Final steps result in a preliminary estimate of the overall load reductions needed to meet water quality standards in the modeled segment. LDCurve is currently only applicable in the state of Texas, but may be updated to model water quality throughout the nation using analogous web services from the EPA STORET database. By using automated data retrievals and computations, the LDCurve tool reduces the amount of time required to create curves and calculate load reductions to a matter of minutes. LDCurve and all supporting materials are available online for free download at: http://tools.crwr.utexas.edu/LDCurve/ . 相似文献
84.
Kristine L. Verdin Bruce Worstell 《Journal of the American Water Resources Association》2008,44(6):1537-1547
Abstract: Estimates of mean annual streamflow are needed for a variety of hydrologic assessments. Away from gage locations, regional regression equations that are a function of upstream area, precipitation, and temperature are commonly used. Geographic information systems technology has facilitated their use for projects, but traditional approaches using the polygon overlay operator have been too inefficient for national scale applications. As an alternative, the Elevation Derivatives for National Applications (EDNA) database was used as a framework for a fully distributed implementation of mean annual streamflow regional regression equations. The raster “flow accumulation” operator was used to efficiently achieve spatially continuous parameterization of the equations for every 30 m grid cell of the conterminous United States (U.S.). Results were confirmed by comparing with measured flows at stations of the Hydro‐Climatic Data Network, and their applications value demonstrated in the development of a national geospatial hydropower assessment. Interactive tools at the EDNA website make possible the fast and efficient query of mean annual streamflow for any location in the conterminous U.S., providing a valuable complement to other national initiatives (StreamStats and the National Hydrography Dataset Plus). 相似文献
85.
Biomagnification profiles of tributyltin (TBT) and triphenyltin (TPT) in Japanese coastal food webs elucidated by stable nitrogen isotope ratios 总被引:1,自引:0,他引:1
The measurement of organotins in the various biotas of coastal food webs with stable nitrogen isotope ratios (δ15N), which increase 3.4‰ per trophic level, can provide a biomagnification profile of organotins through food web. In this study, various biological samples were collected from three localities in Western Japan between 2002 and 2003 for analyses. Tributyltin (TBT) and triphenyltin (TPT) were still detected with a maximum of 99.5 and 8.7 ng wet weight g−1, respectively. Unlike TBT, significant biomagnification of TPT through the food web (expressed by δ15N) was found in all three localities. The log transformed octanol–water partition coefficient (log Kow) of TPT of 2.11–3.43 was overlapped by, but was slightly lower than, that of TBT of 3.70–4.70. Thus, this study demonstrates that although these chemicals have a log Kow lower than 5, at least TPT undergoes significant biomagnification through the food web. 相似文献
86.
87.
Organochlorine pollution in tropical rivers (Guadeloupe): role of ecological factors in food web bioaccumulation 总被引:2,自引:0,他引:2
Coat S Monti D Legendre P Bouchon C Massat F Lepoint G 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1692-1701
Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon were measured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examine the bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a general and heavy contamination of the entire food web. They revealed the strong accumulation of pollutants by juveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in the bioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone and monohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of β-HCH was only influenced by animal lipid content. The biomagnification potential of chlordecone through the food chain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulation process. In contrast, bioconcentration by passive diffusion from water seemed to be the main exposure route of biota to β-HCH. 相似文献
88.
中国温室气体排放清单信息库软件是基于《IPCC导则》1995年版本提供的方法设计的。与清单相关的网页将为国际互联网用户提供三项内容的服务:清单简介,中国若干年温室气体排放清单,以及排放清单信息库软件的下载。 相似文献
89.
Besser JM Brumbaugh WG May TW Schmitt CJ 《Environmental monitoring and assessment》2007,129(1-3):227-241
We evaluated exposure of aquatic biota to lead (Pb), zinc (Zn), and cadmium (Cd) in streams draining a Pb-mining district
in southeast Missouri. Samples of plant biomass (detritus, periphyton, and filamentous algae), invertebrates (snails, crayfish,
and riffle benthos), and two taxa of fish were collected from seven sites closest to mining areas (mining sites), four sites
further downstream from mining (downstream sites), and eight reference sites in fall 2001. Samples of plant biomass from mining
sites had highest metal concentrations, with means 10- to 60-times greater than those for reference sites. Mean metal concentrations
in over 90% of samples of plant biomass from mining sites were significantly greater than those from reference sites. Mean
concentrations of Pb, Zn, and Cd in most invertebrate samples from mining sites, and mean Pb concentrations in most fish samples
from mining sites, were also significantly greater than those from reference sites. Concentrations of all three metals were
lower in samples from downstream sites, but several samples of plant biomass from downstream sites had metal concentrations
significantly greater than those from reference sites. Analysis of supplemental samples collected in the fall of 2002, a year
of above-average stream discharge, had lower Pb concentrations and higher Cd concentrations than samples collected in 2001,
near the end of a multi-year drought. Concentrations of Pb measured in fish and invertebrates collected from mining sites
during 2001 and 2002 were similar to those measured at nearby sites in the 1970s, during the early years of mining in the
Viburnum Trend. Results of this study demonstrate that long-term Pb mining activity in southeast Missouri has resulted in
significantly elevated concentrations of Pb, Cd, and Zn in biota of receiving streams, compared to biota of similar streams
without direct influence of mining. Our results also demonstrate that metal exposure in the study area differed significantly
among sample types, habitats, and years, and that these factors should be carefully considered in the design of biomonitoring
studies. 相似文献
90.
利用环境相关的网络搜索数据构建指标体系,对中国公众环境关心程度进行评价.构建的环境关心指标体系包括环境污染关心、环境知识关心、环境法规关心和环境行为关心4分类指数和42具体指标.分析结果表明,环境关心指数主要受节能、减排、绿色出行等环境行为关心类指标影响;2011年以来,中国公众环境关心指数取值集中在100~200之间,且呈稳步上升趋势,并具有明显的季节性变动特征. 相似文献