Drivers of bird diversity in an understudied African centre of endemism: The Angolan Central Escarpment Forest

Abstract

Natural habitats are being rapidly lost due to human activities. It is therefore vital to understand how these activities influence biodiversity so that suitable guidelines can be established for conservation. This is particularly important in understudied, high biodiversity, areas such as the Angolan Escarpment. Here we examine which habitat characteristics drive bird diversity and endemic species presence at Kumbira Forest, a key site in the Central Escarpment Forest. Bird diversity was sampled by 10 min bird point counts, whereas habitat characteristics were measured by a combination of ground-based vegetation surveys and remotely sensed data modelling of Landsat images. GLM, multi-model inference and model averaging were used to determine the most important variables driving species richness and the presence of endemics. The remote sensing variables performed poorly in predicting presence of Red-crested Turaco Tauraco erythrolophus and Gabela Bushshrike Laniarius amboimensis but they contributed significantly to explain species richness and Gabela Akalat Sheppardia gabela presence, both of which were associated with greater canopy cover. Liana density and elevation were also important explanatory variables in certain cases. Conservation actions at Kumbira should focus on increasing canopy cover and maintaining forest integrity (as measured by liana density), as these actions are likely to have the most positive outcomes for the avifauna.