ESA/SER Joint Meeting (August 5 -- August 10, 2007)

COS 159-8 - The role of frugivorous birds and giant fruit bats as agents for reforestation in south India

Friday, August 10, 2007: 10:30 AM
Santa Clara II, San Jose Hilton
Timothy T. Caughlin, Environmental Studies, New College of Florida, Sarasota, FL, T. Ganesh, Ashoka Trust for Research in Ecology and the Environment and Margaret D. Lowman, Institute of Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA

Tropical forest restoration in open areas is often slowed by limited seed rain and unfavorable conditions for tree seedling establishment. Isolated remnant trees, a common feature of degraded anthropogenic landscapes, may alleviate these problems. Remnant trees increase seedling recruitment in part by attracting frugivorous animals, which amplify the quantity and diversity of seed rain. We examined the sensitivity to human disturbance of volant frugivore visitation to remnant trees in a highly disturbed site of Tamil Nadu, India. Frugivorous bird and Indian flying fox (Pteropus giganteus) visitation to banyan trees (Ficus benghalensis) was recorded across a gradient of human impact, from urban areas to forest edge. Variables quantifying disturbance, including building cover and the amount of vegetation surrounding banyan trees, had relatively little effect on frugivore visitation. For both groups of animal, the most important variable predicting visitation was the size of the focal tree. In our study site, tree seedling abundance and species richness is significantly higher under remnant trees compared to open areas. These results demonstrate that animal seed dispersal, one of the mechanisms leading to remnant tree function as recruitment foci, may be resilient to disturbance. In some regions, incorporating animal seed dispersal services into reforestation plans may increase the efficiency of ecological restoration.