Biogeographical examination of the butterfly fauna in selected West Albertine Rift Forests

Abstract

This study was conducted with the main aim of evaluating the factors that may influence butterfly species richness and distribution (i.e. forest size, altitude, forest disturbance, average rainfall, temperature and distance from the supposed Pleistocene refugium) in 17 West Albertine rift forests (WARF’s), Uganda. Butterflies which were collected by the Forest Department (now National Forests Authority, NFA) and preserved at the Makerere University Museum were used for this study. Relevant biodiversity reports prepared by the Forest Department were reviewed to gather information on the physical and environmental attributes of the forests.

A list of 630 butterfly species was complied for the 17 forests. Cluster, Principal component, Canonical correspondence and regression analyses were done to relate and compare butterfly species richness among the forests in order to establish the relationship between the butterfly species richness and the environmental and physical variables. These analyses helped in identifying the most important variables influencing the butterfly species richness and distribution in the forests.

Forests with similar physical and environmental conditions had similar species richness. The environmental and physical variables which seemed to influence the species richness and distribution in the forests were forest size, number of plant species, altitude and levels of forests disturbance. Plant species richness appeared to be the most significant factor accounting for 49% of the butterfly species richness in the forests. Distance from the supposed Pleistocene refugium also seemed to have been responsible for species richness in the forests although not significantly. However, more research/survey should be done to involve population analysis (number of individuals other than only the number of species should be recorded) to ascertain the effect of forest disturbance on the butterfly species richness and population densities.