Diet and trophic structure of frugivorous bats (Phyllostomidae) in forests and chagras of the Andean–Amazon piedmont, Ecuador

Abstract

Ecuador is experiencing a rapid conversion of its natural habitats, especially in its Andean–Amazon piedmont forests, a conversion that in turn threatens the country’s biodiversity. Frugivorous bats (Phyllostomidae) are not only an example of a taxa affected by habitat loss but may also play a role in overturning habitat loss and degradation. As important seed dispersers, bats are key to many ecological processes such as forest regeneration and succession. To understand Phyllostomidae diversity and trophic structure of Ecuador’s piedmont forests, as well as the potential role of bats in forest recovery through seed dispersal, we sampled bats at both agroforestry (chagras) sites and patches of secondary forest in the buffer zone of the Colonso Chalupas Biological Reserve, Napo Province (750–900 m asl.). For 4 months, we used mist nets and seed traps to sample bats and the seeds they carried. In total, these efforts yielded 224 bats belonging to 33 species. We captured 224 bats belonging to 33 species of which 114 individuals from 24 species transported seeds. We captured more species but fewer individuals of bats in forests (17) than in chagras (15). The bats carried 15,685 seeds of 41 different morpho-seeds belonging to twelve plant genera, with Piper, Cecropia, and Solanum being those with the highest number of seeds. The main disperser we found was Carollia brevicauda, both in the forest (index value = 1.4) and in chagras (2.2). Bat-plant networks were more symmetric in forests (− 1.63) compared to chagras (− 9.28) and showed higher degrees of specialization in chagras. Our results show the great diversity of bats and the seeds they carry and highlight how this traditional agricultural system allows for connectivity between forest patches by providing food niches for seed dispersers. Therefore, we argue both bats and chagras must be considered in forest restoration programs.