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The central objective of this project was to utilize geographical information systems and remote sensing to compare soil erosion models, including Modified Pacific South-west Inter Agency Committee (MPSIAC), Erosion Potential Method (EPM), and Revised Universal Soil Loss Equation (RUSLE), and to determine their applicability for arid regions such as Kuwait. The northern portion of Umm Nigga, containing both coastal and desert ecosystems, falls within the boundaries of the de-militarized zone (DMZ) adjacent to Iraq and has been fenced off to restrict public access since 1994. Results showed that the MPSIAC and EPM models were similar in spatial distribution of erosion, though the MPSIAC had a more realistic spatial distribution of erosion and presented finer level details. The RUSLE presented unrealistic results. We then predicted the amount of soil loss between coastal and desert areas and fenced and unfenced sites for each model. In the MPSIAC and EPM models, soil loss was different between fenced and unfenced sites at the desert areas, which was higher at the unfenced due to the low vegetation cover. The overall results implied that vegetation cover played an important role in reducing soil erosion and that fencing is much more important in the desert ecosystems to protect against human activities such as overgrazing. We conclude that the MPSIAC model is best for predicting soil erosion for arid regions such as Kuwait. We also recommend the integration of field-based experiments with lab-based spatial analysis and modeling in future research. 相似文献
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Human-induced global climate change presents a unique and difficult challenge to the conservation of biodiversity. Despite
increasing attention on global climate change, few studies have assessed the projected impacts of sea-level rise to threatened
and endangered species. Therefore, we estimated the impacts of rising sea levels on the endangered Lower Keys marsh rabbit
(Sylvilagus palustris hefneri) across its geographic distribution under scenarios of current conditions, low (0.3-m), medium (0.6-m), and high (0.9-m)
sea-level rise. We also investigated the impacts of allowing vegetation to migrate upslope and not allowing migration and
of two land-use planning decisions (protection and abandonment of human-dominated areas). Not surprisingly, under all simulations
we found a general trend of decreasing total potential LKMR habitat with increasing sea-level rise. Not allowing migration
and protecting human-dominated areas both tended to decrease potential LKMR habitat compared with allowing migration and abandoning
human-dominated areas. In conclusion, conservation strategies at multiple scales need to be implemented in order to reduce
the impact of global climate change on biodiversity and endangered species. At the regional level, managers must consider
land-use planning needs that take into account the needs of both humans and biodiversity. Finally, at the local scale those
agencies that are in charge of endangered species conservation and ecosystem management need to rethink static approaches
to conservation or else stand by and watch ecosystems degrade and species go extinct. This can be accomplished by bioclimatic
reserve systems where climatically underrepresented areas are included in conservation planning along with the standard concerns
of threat, opportunity, connectivity, and viability. 相似文献
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Many beach management practices focus on creating an attractive environment for tourists, but can detrimentally affect long-term
dune integrity. One such practice is mechanical beach raking in which the wrack line is removed from the beach front. In Texas,
Sargassum fluitans and natans, types of brown alga, are the main components of wrack and may provide a subsidy to the ecosystem. In this study, we used
greenhouse studies to test the hypothesis that the addition of sargassum can increase soil nutrients and produce increased
growth in dune plants. We also conducted an analysis of the nutrients in the sargassum to determine the mechanisms responsible
for any growth enhancement. Panicum amarum showed significant enhancement of growth with the addition of sargassum, and while Helianthus debilis, Ipomoea stolonifera, Sporobolus virginicus, and Uniola paniculata responded slightly differently to the specific treatments, none were impaired by the addition of sargassum. In general, plants
seemed to respond well to unwashed sargassum and multiple additions of sargassum, indicating that plants may have adapted
to capitalize on the subsidy in its natural state directly from the ocean. For coastal managers, the use of sargassum as a
fertilizer could be a positive, natural, and efficient method of dealing with the accumulation of wrack on the beach. 相似文献
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Vander Pol SS Hobson KA Becker PR Day RD Ellisor MB Pugh RS Roseneau DG 《Journal of environmental monitoring : JEM》2011,13(3):699-705
The contents from thick-billed murre (Uria lomvia) eggs collected at four Alaskan colonies in 2002 were analyzed for organic contaminants and carbon δ13C) and nitrogen (δ1?N) stable isotopes. Contaminant concentrations in the eggs varied from below detection limits to 230 ng g?1 wet mass for 4,4'-DDE in one egg from St Lazaria Island in the Gulf of Alaska. Eggs from this colony generally contained higher levels of contaminants and exhibited significantly different patterns compared to eggs from the Bering and Chukchi seas. Stable isotope values also varied geographically; however, these differences appeared to be related to differences in C and N baselines in the food webs instead of differences in prey. Contaminant and stable isotope correlations were inconclusive, suggesting that better information on regional food web differences and differential offloading of contaminants and stable isotopes to the eggs must be obtained before these kinds of data can be fully incorporated into seabird egg contaminant monitoring programs. 相似文献
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