Monday, August 4, 2008 - 4:40 PM

OOS 4-10: Deforestation and pollinator floral fidelity

Berry J. Brosi, Stanford University and Martin Arford, Saginaw Valley State University.

Background/Question/Methods A key challenge for ecology and conservation biology is understanding how ecological interactions—not just “head counts” of species richness—are being altered by ongoing global environmental changes. Though an increasing number of reports are showing relative resilience of bee diversity and abundance to land use change, it remains unclear if pollinator foraging behavior may be affected by landscape context, with potentially significant repercussions for plant reproductive success. In particular, a pollinator's floral fidelity—or number of plant species visited in a single foraging trip—is a major determinant of interspecific pollen transfer and successful pollination. We studied the composition of pollen loads carried by two species of social stingless bees (Apidae: Meliponini) collected across gradients of both distance to forest and forest fragment size in a heavily deforested landscape in southern Costa Rica.

Results/Conclusions While we continue to gather and analyze data, preliminary results indicate that the pollen loads of individual bees reflect greater floral fidelity in sites with 1) a greater proportion of surrounding native habitat and 2) in sites with greater bee diversity. Resource partitioning may help to explain greater pollinator fidelity in sites with higher bee diversity. These results are important for understanding the effects of land use change on ecological interactions and present an argument for conserving even small areas of native habitat in largely deforested areas.