Empirical landscape genetic comparison of single nucleotide polymorphisms and microsatellites in three arid‐zone mammals with high dispersal capacity

Landscape genetics is increasingly transitioning away from microsatellites, with single nucleotide polymorphisms (SNPs) providing increased resolution for detecting patterns of spatial‐genetic structure. This is particularly pertinent for research in arid‐zone mammals due to challenges associated with unique life history traits, such as boom‐bust population dynamics and long‐distance dispersal capacities. Here, we provide a case study comparing SNPs versus microsatellites for testing three explicit landscape genetic hypotheses (isolation‐by‐distance, isolation‐by‐barrier, and isolation‐by‐resistance) in a suite of small, arid‐zone mammals in the Pilbara region of Western Australia. Using clustering algorithms, Mantel tests, and linear mixed effects models, we compare functional connectivity between genetic marker types and across species, including one marsupial, Ningaui timealeyi, and two native rodents, Pseudomys chapmani and P. hermannsburgensis. SNPs resolved subtle genetic structuring not detected by microsatellites, particularly for N. timealeyi where two genetic clusters were identified. Furthermore, stronger signatures of isolation‐by‐distance and isolation‐by‐resistance were detected when using SNPs, and model selection based on SNPs tended to identify more complex resistance surfaces (i.e., composite surfaces of multiple environmental layers) in the best‐performing models. While we found limited evidence for physical barriers to dispersal across the Pilbara for all species, we found that topography, substrate, and soil moisture were the main environmental drivers shaping functional connectivity. Our study demonstrates that new analytical and genetic tools can provide novel ecological insights into arid landscapes, with potential application to conservation management through identifying dispersal corridors to mediate the impacts of ongoing habitat fragmentation in the region. We evaluate landscape connectivity using two different genetic marker types across arid‐zone mammals, which are underrepresented in the landscape genetics literature. We find that topography, substrate, and soil moisture are the main environmental drivers shaping connectivity and that single nucleotide polymorphism (SNP) markers provide finer‐detailed ecological insight. To our knowledge, our study is the first to compare SNPs and microsatellites to empirically test isolation‐by‐resistance hypotheses.