1 resultado para habitat fragmentation

em University of Michigan


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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.