Primates in Fragmented Habitats, Population Response to Anthropogenic Pressures

Habitat fragmentation is frequently cited as a leading threat to faunal species persistence and abundance. Fragmented habitats are often created and bounded by an aggregation of various anthropogenic activities. Primates can be particularly vulnerable to fragmentation pressures because of specialized diet, habitat requirements, and behavioral characteristics. The behavior patterns of the mantled howler monkey (Alouatta palliata ) are focused around its nutritional needs, increasing its vulnerability to habitat disturbance.;In this dissertation I examine the implications of three types of anthropogenic activities: agriculture, tourism and private housing, for the presence of A. palliata in fragmented habitats. Field research was conducted on Ometepe Island, a two-coned volcanic island located in Lake Nicaragua, Nicaragua.;10 m panchromatic Spot 2 satellite images, processed using integrated GIS and image processing software, IDRISI, Taiga 16.04, were utilized to identify potential howler monkey habitat. Focal fragments were indentified in 42 1 km segments across the island. Ground surveys were conducted for habitat suitability, primate presence and adjacent anthropogenic activity in 157 forest and riparian fragments and 28 forest corridors.;Although a sizeable population of howler monkeys was found on the island, both mean howler group size and the mode fragment size were smaller than has been previous shown to be optimal for howler monkey persistence (Mandujano & Escobedo-Morelos, 1980). Travel between fragments and groups is hampered by the lack of connectivity between the fragments and the anthropogenic activity occurring in the matrix surrounding the fragments.;The relationship between the howler population and the human population on the island determined from this research was: 1) The higher the human population density in an area, the lower the howler population density; 2) An agricultural buffer between the fragment and the human population increased the likelihood of howler presence; 3) The greater the time elapse from cessation of disruptive human activity (forest clearing, construction) the greater the potential for howler presence. The research demonstrated the importance of both habitat corridors to connect fragments and buffer zones between fragments and anthropogenic activity. It also indicated small changes in land management and development could encourage long term stability in the howler population, while allowing the continued growth of the island's economy.