COS 64-2 - Landscape genetics of orchid bees in a fragmented tropical landscape

Wednesday, August 10, 2011: 8:20 AM
16A, Austin Convention Center
Sevan Suni, Center for Insect Science, University of Arizona, Tucson, AZ and Berry J. Brosi, Environmental Sciences, Emory University, Atlanta, GA

Habitat fragmentation has been implicated as a major driver of declines in abundance and species diversity across taxa, because it changes the distribution of resources, and reduces genetic connectivity among populations.  Population persistence in fragmented areas depends on dispersal potential and maintenance of gene flow among fragments of habitat.   We used landscape genetic techniques to characterize, for two orchid bee species with equal abundance, levels of genetic differentiation among 22 fragments of tropical forest in Southeastern Costa Rica.  We measured population differentiation with an analogue to the traditional summary statistic Fst, as well as two new measures that more accurately reflect the level of differentiation when highly variable loci are used: G’st and Dest.  


We found a surprising difference in levels of genetic differentiation between the species in all three measures used.  This suggests that caution should be used when using data on abundance to draw conclusions about the conservation status of a species, and also that generalizing conservation status of a community based on studies of just one species may be of limited value.

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