Genetic signature of population fragmentation varies with mobility in seven bird species of a fragmented Kenyan cloud forest

Habitat loss and fragmentation are considered to be key drivers of biodiversity loss, especially in tropical rainforests. Habitat fragmentation can affect genetic population structure by restricting geneflow, reducing effective population size, and increasing genetic drift. Here we apply a Bayesian clustering algorithm to study the genetic population signature of past habitat fragmentation in seven sympatric, forest-dependent bird species of a Kenyan cloud forest archipelago, and compare their levels of historic (genetic differentiation) and current (mark-recapture) mobility. Species significantly varied in current genetic population structure - with more mobile species showing lower genetic differentiation and least mobile ones showing strongest evidence of mutation-drift and migration-drift disequilibria - and in presumed loss of mobility over time. Taking into account potential pitfalls when linking historical and current levels of mobility, results of this study indicate that historic loss of mobility, rather than current mobility per se, may be the strongest predictor of population viability. If confirmed by future studies, this may explain why poor dispersers continue to persist in fragmented landscapes, while more mobile species may be in higher need of conservation than presently assumed