Loss, degradation and fragmentation of natural habitats impose a severe threat on global biodiversity. While the relative effects of these landscape processes on patterns of single species distribution, density and fitness have been well documented for a large number of plants and animals, possible impacts on plant-plant, animal-animal and plant-animal interactions remain largely unknown. Yet, in highly complex ecosystems characterized by species-rich communities - such as rain forests or coral reefs – disruption of such interactions may lead to bottom-up or top-down cascade effects. For instance, in communities were plant regeneration strongly depends on seed dispersal by frugivorous animals, effects of habitat fragmentation on vegetation composition may be both direct through spatial variation in seed predation, seed germination and seedling survival rate in relation to (micro)habitat quality, and indirect through effects on the persistence of the frugivorous species assemblage.

The aim of this study is to test if and how recent fragmentation of the Taita Hills cloud forest in south-east Kenya affects the interaction between fruit-bearing tree species and their suite of avian frugivorous seed dispersers. These questions are addressed through a combination of field observations on foraging and ranging behaviour of seed dispersers with field and laboratory experiments on predation, germination and survival of seeds and seedlings.