Forest Edge Effects on the Behavioral Ecology of L'Hoest's Monkey (Cercopithecus lhoesti) in Bwindi Impenetrable National Park, Uganda

Tharcisse Ukizintambara (2009)

Understanding the complexity of forest edge effects is an important aspect of both ecological and conservation sciences. I studied the relationship between forest edges and the behavioral ecology of the l'Hoest's monkey (Cercopithecus lhoesti) in Bwindi Impenetrable National Park, Uganda. The availability of food had a strong influence on the ranging and foraging ecology of l'Hoest's monkeys in Bwindi forest. I found that the edge group had a larger monthly home range (70.84 ± 12.24 ha) than the interior group (51.81 ± 5.51 ha). The edge group also had a longer mean daily path (2174 ± 467.57 m) than the interior group (1666 ± 416.44 m). I observed greater group turnover and mortality in the edge group than in the interior group. After one year, 8 individuals (22% of the edge group members) were confirmed casualties of human retaliation and eagle attacks, and possibly infanticide. During my study, the interior group lost only 2 individuals (11%). The fact that the edge group occupied larger monthly home range sizes and travelled longer daily distances than the interior group can be attributed to, among other factors, intense forest edge disturbances. I observed behaviors among members of the edge group that appear to allow them to deal with edge-related threats and disturbances. This study has improved our understanding of behavior and survival along forest edges in the l'Hoest's monkeys in Bwindi. Edge-living for this species is associated with high risk. It is clear that forest edges are ecological traps or sink areas that jeopardize the persistence of animal populations living there. Further edge effect studies on the behavioral ecology of the species are needed. These studies will provide valuable additional information on the extent to which l'Hoest's monkeys and other taxa are threatened at forest edges. Such information will contribute to the establishment of appropriate conservation measures including mitigating the problem of primate crop raiding in Bwindi and other tropical forests.

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