Vegetation complexity and bat-plant dispersal in Calakmul, Mexico

Abstract

Fruit production of chiropterochorous plants was studied to test the hypotheses that more complex habitats will harbour: (1) greater plant diversity, (2) higher biomass and density of bat-dispersed plants, and (3) elevated frugivorous bat abundance. We defined habitat complexity as vegetation structural complexity the degree of structural arrangement of vegetation. As forested environments are more complex than modified environments, they should harbour more bat-dispersed species. From 2002 to 2003 in southern Mexico, we observed two fruiting peaks of 56 plant species (20 of which were bat-dispersed) in tropical subhumid forest, tropical semi-deciduous forest and modified open areas. Fruit density was greater in the canopy than in the understorey. Phenology alternated across seasons and habitats. Habitat complexity demonstrated no association with bat abundance, fruit mass or fruit density. A positive relationship between fruit mass and frugivorous bat abundance suggests that fruit mass probably influences frugivorous bat movement across time and space.