Tharcisse Ukizintambara, Ph.D., is a 2010 graduate of the Ph.D. Program in Environmental Studies at Antioch University, New England.

Dissertation Committee

  • Beth Kaplin, PhD (Committee Chair)
  • Peter Palmiotto, DF (Committee Member)
  • Marina Cords, PhD (Committee Member)
  • Alastair McNeilage, PhD (Committee Member)


Forest edge effects, behavioral ecology, habitat characteristics, crop raiding, l'Hoest's monkeys, Bwindi Impenetrable forest, Uganda

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Forest edges are associated with forest edge effects that result from changes in physical features of the habitat, predator species and number, and prominence of human activities and other disturbances that can have direct or indirect impact on the distribution, ecology, and fitness of forest plant and animal species. I conducted a literature review on edge effects on primate species and came up with a classification of primate species in three general categories " thriving, sensitive and resilient species to edge effects " based on behavioral and demographic responses.

In Bwindi Impenetrable National Park, edge effects followed non-monotonic patterns (wave-like) most likely due to the additive influence of edge effects, the history of logging in the area, and the persistent human activities and other disturbances. Such edge effects were more detectable in vegetation canopy cover and density and distribution of pioneer plant species whose dominance could increase or decrease up to 400 m from the park boundary towards the interior of the forest. Such distance, however, can vary considerably depending on variables examined.

L'Hoest's monkeys living along the edge of the Bwindi forest did not appear to be more affected behaviorally by edge effects than an interior group. Both groups spent relatively equivalent amount of time on major behavioral activities such as feeding, travelling and resting. Socializing was significantly less in the edge group compared with the interior group and that is likely to have a detrimental effect on the edge group cohesion. A correlation was found between the abundance of plant food species and the amount of time l'Hoest's monkeys spent feeding on these plant food species along the forest boundary while monkeys of the interior group fed on different items regardless of their abundance. The edge group had also a larger home range than the interior group especially because they expanded it during crop raiding or feeding on native vegetation in fallows outside the park.

Crop raiding was a very risky activity during which l'Hoest's monkeys experienced fatal confrontations with local farmers. Although early work suggested that forest edges were beneficial to wildlife, this study has concluded that forest edges in Bwindi can be ecological traps or sink areas for the edge-resilient l'Hoest's monkey species whose edge groups rely on immigration from the interior forest groups to survive and cope with disturbances and threats associated with forest edges.