Biodiversity and Endangered Species Sample Clauses

Biodiversity and Endangered Species. Biodiversity refers to the number of species supported by a self-sustaining community. Over time, biodiversity normally declines as a community/habitat becomes severely degraded because native species are often depressed or lost. In Lake Erie, biodiversity has been affected by habitat loss and degradation, human disturbance, commercial fishing, the introduction of non-indigenous invasive species and contaminants. Thirty-four species of fish have been given the status of rare, threatened, endangered, species of concern or extinct in Lake Erie. Some of these were dominant members of the historical fish communities. A large number of the dominant species in the Lake Erie aquatic community are now exotics: smelt, alewife, gizzard shad, round gobies, white perch, rainbow trout, pacific salmonids, dreissenid mussels, Echinogammarus, and Bythotrephes. As these exotic species became dominant, the biodiversity of the historical fish, benthic, and plankton communities decreased. Smelt are linked to the decline of blue pike, lake xxxxxxx, the large calanoid, Limnocalanus, the marked decrease in Mysis, and to the near demise of lake whitefish. The fish species mentioned above had been strongly affected by overfishing and habitat degradation prior to the arrival of the exotic smelt in the lake. Alewife and smelt are implicated in the loss of spoonhead, slimy and deepwater sculpins. Recent evidence suggests that contaminants, in particular 2,3,7,8- tetrachlorodibenzo-p-dioxin, may have been responsible for the final loss of lake trout from Lake Ontario, although the role of thiamine deficiency and the resultant early mortality syndrome (EMS) in larval fish cannot be ruled out. This opens the question of the possible roles of contaminants and diet in the loss of lake trout and other species from other Great Lakes. Dreissenids have eliminated the unionid and sphaeriid clams from all but a few refuges in the wetlands, and are hypothesized to be indirectly responsible for the loss of Diporeia from the eastern basin. Echinogammarus has replaced Gammarus fasciatus, itself an exotic, in many regions. Wildlife species using with wetlands for breeding habitats or as important migration stopover habitats make up the majority of rare, threatened, endangered, concern, or extinct species within the basin. For one jurisdiction over 80% of the listed birds (43 species), 40% of the listed mammals (two species), and half of the listed reptiles (eight species) use the wetland or terrestr...