The impact of habitat fragmentation on dispersal of Cunningham’s skink (Egernia cunninghami): evidence from allelic and genotypic analyses of microsatellites

The effects of habitat fragmentation on processes within and among populations are important for conservation management. Despite a broad spectrum of lifestyles and the conservation significance of many reptiles, very little work on fine-scale population genetics has been carried out on this group. This study examines the dispersal patterns of a rock crevice-dwelling lizard, Cunningham's skink (Egernia cunninghami), in a naturally vegetated reserve and an adjacent deforested site. Both genotypic and genic approaches were employed, using microsatellite loci. The spatial organization of individuals with respect to pairwise relatedness coefficients and allele frequencies, along with assignment tests, were used to infer dispersal characteristics for both sexes in a natural and a cleared area. The distribution of relatedness in both habitats was spatially structured, with E. cunninghami showing high pairwise relatedness within their rocky retreat sites. Analysis of relatedness over different spatial scales, spatial autocorrelation of alleles and assignment tests, all indicated that both sexes in the cleared area show less dispersal than their counterparts in the reserve. Furthermore, deforestation may inhibit female dispersal to a greater extent than that of males. The geographical structuring of allele frequencies for adults in the cleared area, but not the reserve, indicates that habitat fragmentation has the potential to alter at least the microevolution of E. cunninghami populations.