Bird abundance and diversity in shade coffee and natural forest in Kenya

Abstract

Coffee, one of the major traded commodities in the world, has economic value for rural livelihood and potentially as habitat for forest wildlife. Previous work in Central Kenya has demonstrated that when cultivated with shade trees, coffee farms can host high levels of bird diversity. However, questions of how the African bird communities in shade coffee farms compares to those in natural forest remained unanswered. Using three visits to each of 160-point count locations in natural forest (80) and shade coffee sites (80) in Central Kenya, we estimated bird abundance and species richness in natural forest and shade coffee. Specifically, we tested hypotheses that the abundance and diversity of birds in shade-coffee and natural forests varies by feeding guilds and forest-association status. We found that, compared to natural forest, shade coffee had higher bird abundance and species richness of carnivores, granivores, omnivores, and insectivores, including understory forest insectivores specifically. Frugivores and nectivores had similar abundance in forest and coffee, but were more species rich in forest and coffee, respectively. The abundance and species richness of forest specialists and forest visitors were higher in natural forest than in shade coffee, whereas forest generalists and birds with no forest association status were more abundant and species rich in shade coffee. Our study confirms the value of remnant native trees within coffee plantations for the persistence and conservation of avian communities, while also clarifying that some groups of birds are reliant on natural forests and unlikely to be conserved in shade coffee farms.