Role of habitat heterogeneity and landscape connectivity in shaping gene flow and spatial population structure of a dominant rodent species in a tropical dry forest

Evaluating how habitat heterogeneity and landscape connectivity influence fine-scale population processes of gene flow and spatial population structure is key for understanding animal dispersal. Liomys pictus is a heteromyid rodent that inhabits tropical dry deciduous and semideciduous forests, where it is a dominant, abundant species and a key element on the ecosystem as seed disperser. We evaluated how landscape features shaped the genetic structure and gene flow at a fine scale among L. pictus populations in a well-conserved natural environment. On the basis of L. pictus ecological characteristics (e.g. dominant species, female philopatry), we predicted that forested areas (irrespective of vegetation type) should facilitate dispersal if the forest vegetation acted as a kind of corridor, and that these patterns will be different between sexes. We tested these assumptions (104 individuals, six sampling localities, 14 microsatellite loci) after checking for discrete genetic groups using Bayesian clustering methods, by assessing the effect of landscape variables on patterns of gene flow combining Mantel and partial Mantel tests, least-cost path and circuit theories. L. pictus differentiated into genetic clusters delimited by clear landscape boundaries. Accordingly, resistance hypotheses results showed that precipitation and stream channels were the main environmental and landscape attributes influencing gene flow. Exchange of a majority of migrants was detected from the center into other sampling localities, indicating higher dispersal throughout deciduous and semideciduous forest corridors, whereas isolation by distance was found only for females. Our approach allowed us to elucidate animal environmental space use, identifying some of the landscape features linked to the species dispersal patterns, which can serve as a basis for the study and comparison with other tropical forests and species. It can also have conservation applications, for instance, preserving the forested corridors we identified as significant for dispersal can likely benefit other codistributed, threatened rodent species.