Data from: Landscape effects on gene flow for a climate-sensitive montane species, the American pika

Climate change is arguably the greatest challenge to conservation of our
time. Most vulnerability assessments rely on past and current species
distributions to predict future persistence but ignore species'
abilities to disperse through landscapes, which may be particularly
important in fragmented habitats and crucial for long-term persistence in
changing environments. Landscape genetic approaches explore the
interactions between landscape features and gene flow and can clarify how
organisms move among suitable habitats, but have suffered from
methodological uncertainties. We used a landscape genetic approach to
determine how landscape and climate-related features influence gene flow
for American pikas (Ochotona princeps) in Crater Lake National Park. Pikas
are heat intolerant and restricted to cool microclimates; thus, range
contractions have been predicted as climate changes. We evaluated the
correlation between landscape variables and genetic distance using partial
Mantel tests in a causal modelling framework, and used spatially explicit
simulations to evaluate methods of model optimization including a novel
approach based on relative support and reciprocal causal modelling. We
found that gene flow was primarily restricted by topographic relief, water
and west-facing aspects, suggesting that physical restrictions related to
small body size and mode of locomotion, as well as exposure to relatively
high temperatures, limit pika dispersal in this alpine habitat. Our model
optimization successfully identified landscape features influencing
resistance in the simulated data for this landscape, but underestimated
the magnitude of resistance. This is the first landscape genetic study to
address the fundamental question of what limits dispersal and gene flow in
the American pika.