Using scientific evidence to guide the conservation of a highly fragmented and threatened Afrotropical forest

Abstract

Fragmentation of forests adversely affects forest-dependent biota, and conservation biologists strive to develop a good understanding of how species respond to changes associated with habitat attrition in order to establish the best conservation strategies. The spatial structure of populations persisting in fragmented landscapes governs their response to habitat fragmentation, and hence dictates the remedial actions that will be most effective for species and habitat conservation. The Taita Hills forests of Kenya are an example of a highly fragmented Afrotropical forest ecosystem embedded in a human-dominated landscape. The spatial structure of the white-starred robin Pogonocichla stellata populations living in indigenous forests across this landscape was examined. Due to its forest dependence and widespread occurrence, the robin was used as a model species to help formulate general conservation guidelines for forest-dependent species and their habitats within this landscape. Results from demographic, genetic and behavioural work point to a mixed spatial structure with elements of patchy population dynamics on a fine scale, and a core-satellite or source-pseudo-sink system on a broader scale. In particular, the findings underscore (1) the importance of dispersal, (2) the importance of small patches, (3) the importance of the largest patch, and (4) the processes underlying problems associated with forest disturbance. We examine the conservation implications of this information, and report on activities already initiated or planned, in line with these findings, for the Taita Hills.