Bat-fruit networks in the neotropical region

Abstract

The study of ecological interactions, mainly mutualistic, using a network approach has resulted in rapid advancements in understanding how these systems are structured at the community level, making it possible to describe patterns and know their determinants. Despite the large number of studies that have investigated different aspects of ecological networks, some taxa are still relatively poorly studied, for example, bats. Bats play a fundamental role in the functioning of tropical ecosystems by dispersing the seeds of hundreds of plant species, mainly those of initial stages of forest succession. In this sense, this thesis seeks to increase what is known about bat-fruit networks responding to a loss of habitat and the factors that determine the role the species play in these system. In the first chapter, we compare the structure and composition of bat-fruit networks in areas of continuous and fragmented forest using a data set of 14 bat-fruit interaction networks in the Atlantic Forest. Although our results demonstrate there are no significant changes in the structure of the networks of these environments, we encountered a lower richness of fruits consumed by bats in fragmented forests, which could have a negative impact on the dynamics and functioning of the ecosystems. The similar network structure of the two environments can be attributed to the core of the network being composed of a few bat species that can occupy both continuous and disturbed areas, thus maintaining the similarity. In the second chapter of the thesis, we increase the data set to 20 networks (primary and secondary data), from Mexico to southern Brazil, and evaluate the importance of species abundance and ecological traits as determinants in the role bat species play in bat-fruit interactions. Our results demonstrate that abundance is more important than biological traits as a determinant in bat-fruit interactions. We attribute this result to the fact that all the networks have two or three superabundant species that interact with more plants than other species in the network.