Summary
In spite of a distribution comprising different forest habitats, blue monkeys (Cercopithecus mitis subgroup) do not tolerate fragmentation or isolation as well as less widely distributed social primate species. Small populations are demographically vulnerable and this monkey is generally absent from small forests (< 150 ha). They are reluctant to disperse over open ground and exist in transient, non-equilibrium or declining metapopulations in which local extinctions are caused by the reduction in forest area and declining habitat quality. Dietary flexibility, particularly the use of low quality folivorous foods may have conferred a competitive advantage on this species group and exemption from the effects of seasonal variation in food supply and quality. This has in turn reduced the need to move among forest fragments, unlike other species whose need to seek alternative feeding sites creates a strong incentive for coordinated group movement among forest patches. Nevertheless, the survival of populations of blue monkeys depends on their persistence in metapopulations. Corridors significantly improve blue monkey metapopulation persistence in the long term. To maintain populations of blue monkeys, large, adjacent and occupied forest patches must be linked in a way that individuals and groups can track changes in the landscape. Translocations and reintroductions of monkey groups is a short-term solution that is not recommended.