Homogeneous genetic structuring and microsatellite allele diversities across White-ruffed Manakin (Corapipo altera) populations in a highly fragmented Costa Rica landscape

Abstract

We explored the effects of recent forest fragmentation on fine-scale patterns of population structuring and genetic diversity in populations of White-ruffed Manakins (Corapipo altera) inhabiting premontane forest patches of varying size in southwestern Costa Rica. Habitat fragmentation is a major conservation concern for avian populations worldwide, but studies on the genetic effects of fragmentation on Neotropical birds are limited. We sampled 159 manakins from nine forest fragments of varying size and isolation within an 18 kilometer radius, and genotyped these birds at 13 microsatellite loci. Bayesian clustering methods revealed that birds from all fragments comprised a single genetic population, and F-statistics showed only modest levels of differentiation between forest patches. We calculated allelic diversity indices for each fragment but found no correlation between genetic diversity and fragment size. These results suggest two possibilities: first, these manakins may retain substantial connectivity via inter-fragment dispersal despite habitat fragmentation, or if dispersal is currently limited, the short period of a half-century since fragmentation may not have been sufficient to impose genetic structuring or to erode allelic diversity.