A Threat To Wildlife And Bio-Diversity
Thesis Statement: The acceleration and diversification of human induced disturbances upon natural ecosystems during the past decades has contributed to wildlife habitat fragmentation. The changes in land use have driven wildlife managers to reconsider the benefits previously attributed to the Edge Effects on wildlife diversity.
Habitat fragmentation has been recognized as a major threat to the survival of natural populations and to the functioning of ecosystems. The reduction of large continuous habitats to small and isolated remnants affects the abundance and species composition of various Taxa. Some possible factors contributing to this decline include changes in food and cover availability, microclimatic effect, evolution of predation, loss of genetic variation, and lack of recolonization following local extinctions. Ultimately, habitat loss and fragmentation are processes that isolate small populations, which have higher extinction rates that may lead to a reduction in biological diversity. The acceleration of the land acreage consumption by human activities to the detriment of natural areas has revealed dramatic changes in the land uses during the past decades. Previously thought to be beneficial to wildlife habitat and diversity, the edge effects have been reevaluated by wildlife managers.
A. Wildlife habitat
In a formal sense, wildlife habitat can be defined as an area with the combination of resources such as food, cover, water, substrate, topography, temperature, precipitation, and security that promotes occupancy by individuals of a given species and allows them to survive and reproduce (Morrison et al., 1992). Usually, the quality and extent of an animal's habitat in large measure governs its ability to survive, and loss of habitat appears to be the greatest single threat to wildlife in the United States. The major factor in wildlife population decline in most areas around the world is the outright loss of habitat and/or the fragmentation of existing habitat into parcels too small or too isolated to support viable wildlife populations (Morrison et al., 1992).
B. Habitat fragmentation
The fragmentation of contiguous areas of homogenous habitat affect the habitat quality of wildlife in particular ways. By altering and modifying the vegetative cover, the quality and variety of the food base has changed. The consequent fluctuations of temperature and moisture levels have created changes in microclimates and in availability of cover. These profound disturbances of the ecosystem balance have brought species together that normally have little contact, and thus have increased rates of parasitism, competition, disease, and predation.
C. Ecotone, or Edge Effects
Usually an animal must rely on two or more plant communities to satisfy its essentials needs (cover, food, water and breeding sites); therefore, the contact zone or region where two different ecosystems...