The effect of selective logging on the primate populations in the Budongo Forest Reserve, Uganda.
Budongo Forest Reserve has been logged selectively for over 60 years. Most compartments in the Reserve have records of the volume of timber removed, date of harvesting, and of treatments carried out to encourage regeneration of valuable timber species. Line transect surveys of the five diurnal primates resident in this forest were carried out in eight of these compartments; two of which had never been logged and six of which had been harvested at approximately 10-year intervals since 1940. Densities were calculated using the computer package DISTANCE. The 'Hazard Rate Model' fitted the observer-primate distance data better than other models. Densities over the whole forest were as follows: Cercopithecus mitis stuhlmannii 43.9/km2; C. ascanius schmidti 33.3/km2; Colobus guereza occidentalis 39.3/km2; Papio anubis 11.7/km2; Pan troglodytes schweinfurthii 1.3/km2. Only C. guereza showed any significant correlation between logging date and animal density, and none of the primates showed any correlation with volume of timber removed. For three primates (C. guereza, C. mitis and C. ascanius) there were significantly higher numbers in logged compartments when compared with those that were not logged. C. mitis and C. ascanius showed significant correlations between percentage of different forest types and densities of primates in each compartment. In particular there was a positive correlation with the 'mixed' forest type that foresters have been encouraging through their management practices. It is concluded that these two primates and C. guereza have benefited from logging in Budongo and that logging has had little effect on the other two primates.