Changes in Forest Composition And

Fragmentation of tropical forests affects the viability of primate populations worldwide. A recent assessment of habitat loss in Latin America has estimated that 9.7% of extant forest was lost between 1980 and 1995 (Chapman and Peres, 2001). Forest fragmentation has many causes (e.g., human encroachment for settlements, agricultural practices, logging, and flooding, Alvarez et al., 1986; Cosson et al., 1999; Chapman and Peres, 2001), but these causes share a common phenomenon. Disruption of contiguous forest creates disjunct patches of forest separated by different types of land use, vegetation, or water, in the case of flooding (Alvarez et al., 1986; Saunders et al., 1991; Terborgh et al., 1997; Cosson et al., 1999). Forest remnants are both smaller, when compared to contiguous forest, and isolated from other forest patches (Saunders et al., 1991). The nature of the surrounding modified habitats—or matrix—imposes a variety of novel (and often detrimental) effects on the plant and animal species still residing within a given fragment (Cosson et al., 1999). In the case of land-bridge islands, water as a barrier has a powerful effect, both in terms of limiting dispersal of resident species and providing an unusable habitat for those species (Turner, 1996; Terborgh et al., 1997; Cosson et al., 1999). Whatever the barrier, fragmentation causes an ‘ecological disruption’ because of a combination of edge effects, and fragment size, shape, and location (Saunders et al., 1991). Interactions between the forest interior and the adjacent habitat along the edge include abiotic effects (changes in such environmental conditions as air temperature, humidity, light intensity), direct biological effects (changes in species distribution and abundance due to the modifications of environmental conditions), and indirect biological