Forest strata use by red colobus monkeys, Piliocolobus badius, in the presence and absence of green vervet monkeys, Chlorocebus sabaeus, in Bijilo Forest Park, The Gambia

Abstract

Ninety percent of primates rely on tropical forests, yet fragmented landscapes alter the distribution of food trees, .increase bush meat hunting, and affect species interactions. I examined mixed-species associations between the arboreal Western red colobus monkey (Pitiocolobus badius) and the terrestrial green ve.rvet monkey (Chlorocebus sabaeus) in The Gambia to determine their effect on the activity budgets and forest canopy use of the red colobus monkeys. The presence of green vervet monkeys affected both canopy use and feeding behavior of red colobus monkeys. The distribution of red colobus across the forest strata was significantly different in the presence and absence of green vervets. Red colobus monkeys utilized the understory and forest floor most when green vervets were present. Furthermore, when green vervets were present, a greater proportion of red colobus fed. Mixed-associations may offer the endangered red colobus monkeys greater access to food resources in small, depleted forest patches.