Forest loss alters bat diversity, trophic interactions and natural pest consumption in adjacent agricultural land

Abstract

Increasing agricultural production to meet rapidly growing demand for food is driving widespread conversion of natural habitats to arable land. Safeguarding biodiversity while improving food security of local communities remains a key global challenge, especially in regions such as Sub-Saharan Africa, where the population is expected to double by 2050. To develop sustainable solutions to this trade-off, we need to better understand natural regulation processes. Bats are widely regarded as a major predator of crop pests, yet little is known about them in African agroecosystems. We investigated the role of bats as natural pest consumers across land-use gradients from intact forest to cropland in two contrasting Afrotropical systems of Zambia and Ghana. Between 2021 and 2022, 2151 bats of 61 species were captured across four field seasons. From these, metabarcoding dietary analyses of 895 faecal samples of insectivorous bats were performed. Bats were found to consume detrimental agricultural pests in both systems, with differing proportions and prevalence of pests in their diets across localities and agroecosystem types (e.g., maize and cacao). We find a shift in bat taxonomic and functional diversity, with some forest-dependent species absent from agricultural areas, particularly on the clear-cut edges of tropical evergreen rainforests of Ghana. Intraspecific dietary analyses of bat species present along the gradient show alteration of trophic interactions, with reduced dietary breadth and nestedness with increasing distance from the forest. Our study highlights the degradation of ecological interactions in changing landscapes, with important implications for conserving their function and stability.