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291.
We present four reconstruction estimates of Arkansas River baseflow and streamflow using a total of 78 tree-ring chronologies for three streamflow gages, geographically spanning the headwaters in Colorado to near the confluence of the Arkansas-Mississippi rivers. The estimates represent different seasonal windows, which are dictated by the shared limiting forcing of precipitation on seasonal tree growth and soil moisture—and subsequently on the variability of Arkansas River discharge. Flow extremes that were higher and lower than what has been observed in the instrumental era are recorded in each of the four reconstructions. Years of concurrent, cross-basin (all sites) low flow appear more frequently during the 20th and 21st Centuries compared to any period since 1600 A.D., however, no significant trend in cross-basin low flow is observed. As the most downstream major tributary of the Mississippi River, the Arkansas River directly influences flood risk in the Lower Mississippi River Valley. Estimates of extreme high flow in downstream reconstructions coincide with specific years of historic flooding documented in New Orleans, Louisiana, just upstream of the Mississippi River Delta. By deduction, Mississippi River flooding in years of low Arkansas River flow imply exceptional flooding contributions from the Upper Mississippi River catchments.  相似文献   
292.
Environmental Science and Pollution Research - It is important to establish the toxicity pesticides against non-target species, especially those pesticides used in commercial formulations....  相似文献   
293.
Environment Systems and Decisions - This paper proposes a framework to systematically evaluate and select attributes of decision models used in disaster risk management. In doing so, we formalized...  相似文献   
294.
The prevalence and distribution of soil and water samples contaminated with enteroparasites of humans and animals with zoonotic potential (EHAZP) in Apucaraninha Indigenous Land (AIL), southern Brazil, was evaluated. An environmental survey was conducted to evaluate the presence of parasitic forms in peridomiciliary soil and associated variables. Soil samples were collected from 40/293 domiciles (10 domiciles per season), from November 2010 to June 2011, and evaluated by modified methods of Faust et al. and Lutz. Analyses of water from seven consumption sites were also performed. The overall prevalence of soil samples contaminated by EHAZP was 23.8 %. The most prevalent parasitic forms were cyst of Entamoeba spp. and eggs of Ascaris spp. The highest prevalence of contaminated soil samples was observed in winter (31 %). The probability map obtained with geostatistical analyses showed an average of 47 % soil contamination at a distance of approximately 140 m. The parasitological analysis of water did not detect Giardia spp. or Cryptosporidium spp. and showed that all collection points were within the standards of the Brazilian law. However, the microbiological analysis showed the presence of Escherichia coli in 6/7 sampled points. Despite the low level of contamination by EHAZP in peridomiciliar soil and the absence of pathogenic protozoa in water, the AIL soil and water (due to the presence of fecal coliforms) are potential sources of infection for the population, indicating the need for improvements in sanitation and water treatment, in addition periodic treatment of the population with antiparasitic.  相似文献   
295.
296.
Large areas of public lands administered by the Bureau of Land Management and located in arid regions of the southwestern United States are being considered for the development of utility-scale solar energy facilities. Land-disturbing activities in these desert, alluvium-filled valleys have the potential to adversely affect the hydrologic and ecologic functions of ephemeral streams. Regulation and management of ephemeral streams typically falls under a spectrum of federal, state, and local programs, but scientifically based guidelines for protecting ephemeral streams with respect to land-development activities are largely nonexistent. This study developed an assessment approach for quantifying the sensitivity to land disturbance of ephemeral stream reaches located in proposed solar energy zones (SEZs). The ephemeral stream assessment approach used publicly-available geospatial data on hydrology, topography, surficial geology, and soil characteristics, as well as high-resolution aerial imagery. These datasets were used to inform a professional judgment-based score index of potential land disturbance impacts on selected critical functions of ephemeral streams, including flow and sediment conveyance, ecological habitat value, and groundwater recharge. The total sensitivity scores (sum of scores for the critical stream functions of flow and sediment conveyance, ecological habitats, and groundwater recharge) were used to identify highly sensitive stream reaches to inform decisions on developable areas in SEZs. Total sensitivity scores typically reflected the scores of the individual stream functions; some exceptions pertain to groundwater recharge and ecological habitats. The primary limitations of this assessment approach were the lack of high-resolution identification of ephemeral stream channels in the existing National Hydrography Dataset, and the lack of mechanistic processes describing potential impacts on ephemeral stream functions at the watershed scale. The primary strength of this assessment approach is that it allows watershed-scale planning for low-impact development in arid ecosystems; the qualitative scoring of potential impacts can also be adjusted to accommodate new geospatial data, and to allow for expert and stakeholder input into decisions regarding the identification and potential avoidance of highly sensitive stream reaches.  相似文献   
297.
A comprehensive list of planning criteria for optimizing compliance in Marine Protected Areas (MPAs) was compiled and used to compare the views of recreational fishers and compliance officers for facilitating voluntary compliance in the Port Stephens - Great Lakes Marine Park (PSGLMP). Expert working groups were tasked separately with: 1) criteria identification and weighting; 2) scoring of no-take zones; 3) prioritizing and determining uncertainty; and 4) analysis of results and sensitivity testing. Multi-Criteria Analysis (MCA) revealed that both groups had similar perspectives and recommendations, despite weighting the individual planning criteria differently. Significantly, "manageability" scores for no-take zones from MCA appeared to correlate well with past numbers of enforcement actions recorded for each zone. This provides empirical evidence that adopting manageability criteria during the planning of MPAs could lead to a marked increase in voluntary compliance. As a result, greater consideration to compliance planning during MPA design and zoning is recommended in order to optimize voluntary compliance. Whilst the majority of no-take zones in the PSGLMP case study were evaluated as being relatively effective in terms of optimizing voluntary compliance, there remains considerable potential to improve design, management and use of the poorer performing zones. Finally, the study highlighted the value of recreational fisher engagement in MPA planning processes to maximize voluntary compliance and manageability.  相似文献   
298.
In projects of community development and natural resource management, local residents collaborate with government and NGOs on decisions about forest management and participate in programs designed to improve livelihoods while sustaining natural resources. This paper uses case studies and survey data in Gansu province of northwest China to explore social, ecological, and economic outcomes of community-based co-management (CBCM). Findings show that CBCM appears to have significantly increased livelihoods for local community residents overall. Forest condition and attitudes about forest conservation were also improved. However, economic benefits were not enjoyed uniformly within the communities because, although CBCM projects are nominally available to all, certain subgroups within communities are less likely to participate. Greater education, being married, and access to information are all strongly correlated with participation and thus the economic benefits of CBCM projects. Women, although they frequently participate in household decisions, are infrequent participants in CBCM projects, perhaps because project design does not meet their needs. Future improvements to CBCM project design should include increased access to information, education, and equitable treatment of diverse stakeholders in the decision-making process. Such improvements would likely lead to improvements in livelihoods as well as more sustainable forest management and conservation.  相似文献   
299.
Seafood from a changing Arctic   总被引:1,自引:0,他引:1  
We review current knowledge about climate change impacts on Arctic seafood production. Large-scale changes in the Arctic marine food web can be expected for the next 40–100 years. Possible future trajectories under climate change for Arctic capture fisheries anticipate the movement of aquatic species into new waters and changed the dynamics of existing species. Negative consequences are expected for some fish stocks but others like the Barents Sea cod (Gadus morhua) may instead increase. Arctic aquaculture that constitutes about 2% of global farming is mainly made up of Norwegian salmon (Salmo salar) farming. The sector will face many challenges in a warmer future and some of these are already a reality impacting negatively on salmon growth. Other more indirect effects from climate change are more uncertain with respect to impacts on the economic conditions of Arctic aquaculture.  相似文献   
300.
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