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.

Keywords:

• chiropterochory
• fruit density
• fruit mass
• fruiting pattern
• synchrony

Acknowledgements

We thank Consejo Nacional de Ciencia y Tecnología (CONACyT, Scholarships: 60371, 21467), Posgrado en Ciencias Biológicas de la UNAM, and Fundación Pablo García (Scholarships: 848/01) for economic support. We also want to express gratitude to the Dirección de la Reserva de la Biosfera Calakmul, to the Instituto Nacional de Antropología e Historia de Campeche, Calakmul municipality authorities, and the authorities of Xbonil and Conhuás for allowing us to work in the area and use their infrastructure, and to the ejidatarios of both villages for their help in the field. Scientific permits were provided by the Dirección General de Vida Silvestre‐SEMARNAT, and Comisión Nacional del Agua provided data on temperature and precipitation in Calakmul. This research is a contribution from the Program for Conservation of Mexican Bats. We also thank L.G. Herrera, A.T. Peterson, J. Arroyo, J.M. Weber, E. Nichols, P. Weihe and J.A. Alayón. The anonymous reviewers provided valuable contributions to the manuscript, and D. Álvarez helped with identification of some species of plants, fruits and seeds. Logistical help in the field was provided by A. Canul, A. López, S. Perez, D. Martínez, L. Flores, M. Fierro and the Pech brothers.