Bird and bat diversity, herbivory and trade-offs with yield in coffee agroforests in Arabica coffee's native range

Agroforestry systems have the potential to provide benefits for conservation, natural pest control and farmer livelihoods. Yet, we need a clearer understanding of how environmental drivers shape different components of biodiversity, how these biodiversity components contribute to suppressing pest levels, and how biodiversity trades off with yield. We focused on the diversity and role of birds and bats across different types of coffee farms in Arabica coffee's native range in southwestern Ethiopia. While elevation, canopy cover, shade tree community composition and surrounding forest cover did not explain bird and bat species richness, the composition of the bird and bat community was significantly influenced by the composition of the shade tree community. Herbivory was unrelated to the species richness and community composition of insectivorous birds and bats. We found no trade-off between bird and bat species richness and coffee yield, but the composition of the bird, but not bat, community changed with increasing yield, where forest specialist birds rapidly declined in abundance from low to mid-yielding sites. Overall, we suggest that the similar levels of bird and bat species richness and an absence of a relationship with herbivory across different types of agroforests are due to the diverse mosaic agricultural landscape and lack of agroforests with very high management intensities (which are common in other parts of the world). From a conservation point of view, intensification of coffee management in the lowest-yielding sites would threaten biodiversity in terms of forest specialist birds. However, is it also important to learn more on the potential positive roles of biodiversity in those parts of the landscape where coffee is managed for high yields. From both a conservation and sustainable management point of view we urgently need more insights into the taxonomy, life-history, habitat preferences and foraging ranges of East African bats.