Ecological impacts of forest disturbance on ring-tailed lemurs (Lemur catta) in the Beza-Mahafaly Special Reserve region: Implications for conservation in an altered landscape.

摘要

Forest disturbance, both natural and anthropogenic, has been recognized as a severe threat to primate populations on a global scale. Moreover, primates tend to vary, between species and between sites, in their tolerance and response to disturbances. Perhaps because of this variability, the effects of ecological perturbations on primates remain relatively poorly understood. Understanding disturbance effects and the ecological variables that are particularly potent for primates will provide sound data for effective conservation management. In this dissertation, I examine the effects of anthropogenic disturbance and a destructive cyclone on the ecology and behavior of the ring-tailed lemur (Lemur catta) at Beza Mahafaly Special Reserve in southwestern Madagascar. I present data from four study groups (two in the protected Reserve and two in anthropogenically disturbed, unprotected habitats). Cyclone Ernest affected this region when it made landfall in January of 2005, seven months prior to the beginning of this study. These natural and anthropogenic disturbances have altered forest structure and phenology. Groups inside the Reserve tend to eat more terrestrial herbs and vine leaves. Additionally, Reserve Groups also rely on a fewer number of species for the majority of their diet. It appears that in more marginal habitats, L. catta is able to diversify its diet and exploit foods that might not be their primary choice. Non-Reserve Groups also inhabited smaller home ranges, but had higher daily path lengths than groups residing in the Reserve. Additionally, Non-Reserve Groups utilize open canopy areas and habitats with higher degrees of disturbance to a greater extent than Reserve Groups. Non-Reserve Groups spend more of their active time both feeding and traveling than groups inside the Reserve. Non-Reserve Groups devoted less of their time to resting compared to Reserve Groups. Groups in unprotected habitats have greatly reduced group cohesion, lower rates of grooming, and elevated levels of aggression. Preliminary data show higher rates of injury and mortality for groups living outside of the protected forest. Anthropogenic habitat alterations, coupled with stochastic changes from tropical storms, have changed the landscape both in and around BMSR and contributed to survival challenges for L. catta in the area.