The impact of human forest disturbance on the endemic avifauna of the Udzungwa Mountains, Tanzania

Abstract

Studies of how avian communities are affected by human forest disturbance have given variable results. In order to focus conservation efforts we need comparative data for studying the relationship between community resilience and ecological predictability over much longer periods of time. This paper compares avian communities in mature forest and adjacent disturbed forest at a site in the Tanzania-Malawi Mountains which has probably had humid forest cover permanently since the Tertiary. At the same time the study presents a possible model design for such studies, which may be a suitable compromise between the needs for quantitive data and logistical constraints during exploratory visits to areas difficult of access. The method is highly time efficient as it is based on continuous recording of all birds during 'random' walking through the forest. There were at least 70 species in disturbed, against 61-65 species in different kinds of adjacent mature forest, but with a marked loss of range-restricted species as we passed from mature to disturbed forest. Most seriously affected were birds of the shaded forest understorey, but also the larger insectivores of mixed canopy feeding parties declined. These species search for food in the masses of epiphytic lichens, mosses and ferns in mature forest canopies. Comments are given on the specific requirements of six species of conservation concern.