Habitat use by the blue monkey (Cercopithecus mitis stuhlmanni) in the colonizing and old growth forest at Ngogo, Kibale National Park, Uganda

Abstract

The main aim of this study was to test the hypothesis that colonizing forest fosters a better survival environment for blue monkeys than old-growth forest, at Ngogo, Kibale National Park. This may compel them to spend more time foraging in colonizing than in old-growth forest. In order to test this hypothesis, two groups of blue monkeys were followed for a period of six months (January-June 2009). Data were collected on ranging patterns, activity-time budgets, diet and frequency of polyspecific associations while the two groups were foraging in colonizing and old-growth forests. The daily range (number of quadrats entered) was significantly greater in the colonizing forest than the old-growth forest for only group 2. Similarly, the distance traveled by the blue monkeys on a daily basis was significantly longer in the colonizing forest than in the old-growth forest for group 2. However, daily range and travel did not differ between the two habitat types for Group 1. Blue monkeys of group 1 were significantly involved in resting, playing and aggressive activities in the old-growth forest than in the colonizing forest. Monkeys were more vigilant, as indicated by the frequency of scanning, in the colonizing forest than in the old-growth forest. However, group 2 had significant differences in all activities between the colonizing and the old-growth forest apart from self-grooming and aggressive behavior. Blue monkeys of both groups ingested more invertebrates in the colonizing forest than in the old-growth forest. Fruits were usually the most frequently used plant food component, but foliar foods and seeds were periodically used at high frequencies. Blue monkeys associated significantly less with other primate species while in the colonizing forest than in the old-growth forest. The results from this study show that the colonizing forest fosters the survival of the blue monkeys at Ngogo; therefore the colonization of grasslands by forest at Ngogo seems to be beneficial to blue monkeys and may probably lead to an increase in the population of blue monkeys in the area.