PredatorPrey Relationships in West Virginia Essay

PredatorPrey Relationships in West Virginia - Essay Example Many believe the carrying capacity, the maximum number of animals the environment can support has been reached this can have devastating outcomes (Grafton 2008). There are major problems with deer populations in many states; however, in West Virginia populations can run as high as 75 deer per square mile (Williams 2005). In all cases, the root of the problem stems from a lack of natural predators and an ecological negative feedback loop that involves declines in forest health and composition. White tailed deer populations in excess of 20 per square mile are largely responsible for lack of woody and herbaceous regeneration (Grace 2008). Habitat impacts from such extensive deer overpopulation range from destruction of native understory, as deer are mostly browsers, eliminating low growing shrubs and herbaceous material to loss of small mammals and their predators. They are also responsible for dramatic changes in the hardwood diversity of eastern forests when they browse on immature hardwoods, killing them and thereby changing the fundamental structure of the canopy (Grace 2008). This affects every species in the system. The US Forest Service determined at more than 20 deer per square mile, there is a loss of many common bird species such as cerulean warblers, yellow-billed Cuckoos, indigo buntings, eastern peewees, and even robins disappear (Williams 2005). With the loss of these botanical species and associated birds, there is also a loss of small mammals due to lack of adequate cover and food resources (Broache 2005). Interestingly, it has been shown that silvicultural practices in managed hardwood forests of West Virginia have contributed to an initial increase of small mammal abundance diversity, usually until succession returns to the forest area (Kirkland 1975). This is thought to be due to an increase in consumption of seeds and seedlings, which in the long term has a deleterious impact on forest regeneration. In addition to anthropological restructuring of the forest's ecosystem, deer overpopulation has compounded the problem. Habitat alteration contributes to what still may be the root of the problem, which is the loss of the deer's natural predators from the system; bear, wolves and cougar that began in the 1700s. Numbers of the eastern timber wolf, black bear, and eastern cougar and all at historic lows since the area was first settled in the 1700s. Black bear in the state are estimated to be fewer than 8,000 individuals and both the wolf and cougar are listed on the Endangered Species list (Weaver 2007, USFWS 2008). Studies in Yellowstone have shown that large predators actually increase herd fitness by 30-40 percent when the herd has good quality habitat in which to bed, hide and feed upon (Brown 2006). Large predator prey relationships were studied over the long term at Michigan's Isle Royale National Park, where wolf and moose populations were shown to rise and fall in connected cycles (Milhill, 2008). The lack of predators in National Parks such as Yosemite and Zion has lead to large deer populations where stream bank erosion and loss of habitat for amphibians and butterflies have occurred (Milhill, 2008). With the lack of these large predators to help maintain deer populations, the dee r are beginning to overpopulate the landscape, which hurts not only the ecology of the