cies which are adapted solely for survival in the rapidly disappearing unfragmented habitat. Besides physically changing a part of the original habitat, decreasing the size of the original habitat can reduce the biological diversity of an area in several ways. Reducing biodiversity of an area may occur if habitat fragments are smaller than the home range of the animal with the largest home range that existed within the intact ecosystem. Many birds have large home ranges because they require patchily distributed resources. For example, one breeding pair of ivory billed woodpeckers require five to six square miles of undisturbed contiguous bottomland forest, and a single European goshawk requires twenty to forty-five miles for his home range. If a habitat fragment exists that is smaller than the minimum area required by a given species, individuals of that species will not likely be found within that habitat fragment. For example, the Louisiana waterthrush is rarely found in small woodlots because they require open water within their home range, and most small woodlots do not have year-round streams or ponds. If a species requires two or more habitat types, they are often susceptible to local extinction due to habitat fragmentation, because often they are unable to freely move between the different habitat types. The blue-grey gnathatcher moves from decidous woodland to chapparral (a warm area) during the breeding season, and if one of the two habitat types can not be readily accesed, they are very susceptable to local extinction. Loss of any species from a community may have secondary effects that revrberate throughout the ecosystem. For example, loss of a top predator from an area because the fragment is too small can cause numbers of small omnivores to increase, which in turn may cause excessive predation pressureon songbird eggs and hatchlings, ultimately resulting in reproductive sucess. Tropical communities are oftem...
