Document: ELS-3-50-7

The nocturnal and crepuscular ecology of a diurnal monkey, Colobus guereza, in the Kakamega forest, Kenya.

CLELAND, E.E.* ¹ and F.VON HIPPEL ²

Stanford University, Stanford, CA 94305 USA ¹
University of Alaska, Anchorage, AK 99501 USA ²

Abstract:
Land use changes by humans threatens many species worldwide as habitat is lost through degradation and fragmentation. Time-delays in the response of species to these changes may result in several-generations elapsing before the consequences of fragmentation are realized. Furthermore, individual species utilize ecological resources on different spatial and temporal scales within a landscape. These interactive effects of species and ecological resources make predictions about population decline due to fragmentation difficult and highly variable from species to species. Guerezas utilize specific trees in their home range as sleeping trees, and spend over half of their time in these trees. This study supports earlier findings that guerezas sleep in or near important feeding trees away from other groups and that guerezas sleep only in tall trees that allow the greatest predator protection. This study investigated the ecological characteristics of sleeping and feeding trees in relation to the home range of two neighboring groups of guerezas. Guerezas display great variability in the range of tree species, individual trees and tree morphology that they utilize for feeding. The character of their sleeping trees was more constrained; most of the time they used a few preferred species. Further, they sleep in specific individual trees that allow superior predator avoidance. Groups of guerezas in a study site in the Kakamega Forest were found to decline in number from 18 groups in 1992 to 12 groups in 1998. The western half of the study site did not show a decline in groups: This area has more human foot traffic which might reduce predation levels. The complete loss of the Kakamega Forest can be predicted to occur in 2031 if clearing continues at its historical rate. Given that the character of sleeping trees is highly constrained and may influence guerezas' ability to avoid predators, sleeping trees are an important ecological resource to consider in order to conserve guereza populations in this increasingly degraded forest.

Keywords: sleeping trees, guerezas, Kakamega Forest

This abstract is being presented at: 8:00 AM in session:
Oral Session #21: Small Mammal Population Ecology.