Same scenario, different scripts: Landscape genetics in two codistributed subterranean rodents of the genus Ctenomys

Abstract

Subterranean rodents of the genus Ctenomys typically occupy fragmented habitats, many currently altered by anthropogenic development. These changes affect functional connectivity among individuals, reducing gene flow levels. This study assessed the functional connectivity of two sympatric species of subterranean rodents, Ctenomys australis and Ctenomys talarum, examining the impact of landscape changes on their population genetic structure at a fine spatial scale. We conducted a spatially continuous sampling over 12 km of coastline in Southeastern Buenos Aires province, Argentina, genotyping 91 and 106 individuals of C. australis and C. talarum, respectively, using 10 to 12 microsatellite loci. We applied various spatial layers characterizing both species´ habitats to evaluate the landscape configuration´s effect on individual gene flow. We employed Bayesian genetic clustering methods to infer population structure levels. Ctenomys talarum showed greater structure than C. australis. NDVI temporal variation was the main factor influencing C. australis´ genetic structure, whereas suitable habitat, linked to the current landscape configuration, was the most significant factor in shaping C. talarum´s genetic structure. Differences in dispersal capacity and habitat specificity appear to have influenced the population genetic structures of these species. The results indicated varying sensitivities to landscape changes; temporal landscape variations primarily impacted C. australis´ genetic connectivity, whereas for C. talarum, the current landscape configuration was more influential.