The effects of habitat loss on bat-fruit networks

Abstract

Habitat loss and fragmentation typically lead to species loss and, consequently, changes in the structure and stability of interaction networks. These changes may lead to important limitation of crucial ecosystems services such as seed dispersal. Here, we compared the spatial structure and species composition of bat-fruit interaction networks in continuous and fragmented forests based on the compilation of 14 datasets from the highly diverse and threatened Atlantic Forest sites in Brazil. As predicted, the number of bat-dispersed species was reduced in fragmented forests. Surprisingly, in both continuous and fragmented forests, bat-fruit networks were nested and modular and presented high complementary specialization. Bat species from genera Artibeus, Carollia, and Sturnira, as well as five plant genera (Cecropia, Ficus, Piper, Solanum, and Vismia) played a central role in both continuous and fragmented forests, revealing small effects of habitat loss on the phylogenetic identity of core species. These bats are considerably tolerant to habitat loss and may support seed dispersal of they preferred plants also in fragmented forests, which explains the similarities of the networks between continuous and fragmented forests. In addition, these key plants provide food resources continuously throughout the year, which facilitates the persistence of seed disperser bats year-round in the community. Although our results indicate that habitat loss had little influence on the structure of the bat-fruit interactions, we evidenced that fragmentation reduces the number of resources consumed and dispersed by bats, which may have negative impacts on forest dynamics and ecosystem functioning.