915 resultados para Wetland construída
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The diet of Common Chiffchaffs Phylloscopus collybita wintering in a Mediterranean wetland (El Hondo Natural Park, SE Spain) was studied by analysing the gizzard content of 17 individuals that died accidentally when trapped for ringing. Prey availability was assessed via water-trap sampling over two winters. The bulk of the diet was composed of midges (Chironomidae), which were found in all the gizzards and represented approximately 95% of the prey. Brachycera flies were one of the most captured taxa in the water-traps but represented less than 0.5% of the total number of prey consumed. Compositional analysis revealed very strong prey selection, with Chiffchaffs selecting clumped and less mobile prey, such as chironomids, and avoiding abundant but fast-escaping prey, such as Brachycera.
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The “El Hondo Nature Park” is mainly composed of a series of irrigation channels and water reservoirs, subjected to various regimes of management as well as reed and vegetation control, thus creating a great variety of habitats and situations. To determine the influence of these habitats and management regimes on the local bird community, a set of characteristics of these channels and their surrounding area were analysed with a Correspondence Analysis (CA). The degree of reed development in channels and the presence in the surroundings of orchards and other reed formations were the most decisive factors to explain the probability of occurrence of reed birds and waterbirds, as well as bird species richness and abundance. Other bird species were not directly influenced by channel variables, but only by those of surrounding land uses.
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Mode of access: Internet.
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Grant R803971.
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"EPA/600/3-91/010."
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Includes index.
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"In cooperation with the national and regional wetland plant list review panels."-- Cover.
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"March 1994."
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Mode of access: Internet.
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"0123-2833-MTDC"--Cover.
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Wetlands are extremely valuable natural features that have decreased significantly in number over time in Illinois and the United States ... Their important functions include flood protection, water conservation in times of drought, groundwater recharge, improvement of water quality through sediment reduction and contaminant removal, and providing habitat for native animals and plants, including many sensitive and state-listed threatened and endangered species ... Due to a federal "no net loss" policy on wetlands adopted through executive order by President George H. Bush in 1990, as well as a prevailing heightened interest in conservation in general, there is currently considerable interest in the restoration and creation of wetlands. Both Section-404 of the Clean Water Act of 1972 and the Swampbuster Provision of the Food Securities Act of 1985 require compensation or mitigation for the loss of wetlands. A number of federal and state programs such as Section 319 of the Clean Water Act and the Conservation Reserve Program within the Natural Resources Conservation Service (NRCS) encourage wetland restoration and creation. In addition, various conservation organizations, such as The Nature Conservancy and Ducks Unlimited are very active in wetland restoration. Despite wetland restoration efforts and the national goal of no net loss, wetlands and wetland functions continue to be lost due to degradation of existing wetlands ... Unfortunately, no reliable information exists on the quality of existing wetlands or on trends in wetland quality over time ... The functional quality of existing wetlands is likely decreasing in many areas due to the combined effects of habitat fragmentation, alteration of hydrology, invasive species, and continued input of nutrients and pollutants. Furthermore, it is still debatable whether created or restored wetlands can adequately replace the suite of ecological functions provided by natural wetlands ... and the failure of many wetland compensation projects contributes to a continued national net loss of wetland functions ... The need for post-construction site monitoring and assessment of created and restored wetlands to evaluate functional success is widely recognized. ... At this time, there is little agreement on how to assess the success on quality of wetland restorations or creations.
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Project no.: 20.146.
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"Project: 91/087."