Avian guild assemblages in forest fragments around Budongo Forest Reserve, western Uganda

Abstract

Remnant forest fragments provide an opportunity for conservation in fragmented landscapes but some patches are more useful than others. Forest fragments around Budongo Forest Reserve, an Important Bird Area in western Uganda, were surveyed to explore the effects of different aspects of habitat fragmentation on bird guild composition. We recorded 1 128 individuals of 75 bird species over 7 056 net hours. The greatest number of birds and species were recorded in the forest fragments that were large, near to the continuous forest and surrounded by subsistence farmland. However, rarefied species richness was not affected by distance, size or matrix type; instead, forest specialist species were replaced by generalists and visitors with increasing fragmentation. The proportion of forest specialists and of terrestrial insectivores decreased with distance from the main forest, canopy openness and matrix intensity but not with fragment area. The findings show that bird assemblages vary in their response to habitat fragmentation but within guilds the response to fragmentation can be consistent, and can make ecological sense. Forest bird conservation can therefore benefit from information on species ecology when deciding which bird species and which parts of the landscape are to be prioritised for conservation or monitoring purposes.

Keywords: forest specialist, fragment size, frugivore, insectivore, isolation, land use, matrix, species richness