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 populati ons 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 lizar d, Cunningham's skink (Egernia cunningham), in a naturally vegetated reserv e and an adjacent deforested site. Both genotypic and genic approaches were employed, using microsatellite loci. The spatial organization of individua ls 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 relate dness in both habitats was spatially structured, with E. cunninghami showin g high pairwise relatedness within their rocky retreat sites. Analysis of r elatedness over different spatial scales, spatial autocorrelation of allele s and assignment tests, all indicated that both sexes in the cleared area s how Less dispersal than their counterparts in the reserve. Furthermore, def orestation may inhibit female dispersal to a greater extent than that of ma les. The geographical structuring of allele frequencies for adults in the c leared area, but not the reserve, indicates that habitat fragmentation has the potential to alter at least the microevolution of E. cunninghami popula tions.