Fine-scale landscape genomics in an ecological generalist, Elgaria multicarinata

Researcher: Erin Toffelmier

Affiliations: UCLA

Summary: Understanding how habitat heterogeneity impacts gene flow is essential for characterizing how variable landscapes contribute to population structure and genetic differentiation. This is especially true in in widely ranged species, which cumulatively experience more landscape heterogeneity across their entire range. This may provide more opportunities for both adaptive and neutral processes to operate differentially across spatial scales. However, landscape genetic studies are most frequently carried out on a regional or range-wide scale, often overlooking fine-scale landscape patterns that contribute to population structure on a local scale. In western North America, Elgaria multicarinata, the southern alligator lizard, is a widely ranging ecological generalist. It is distributed from southern Washington, USA to northern Baja California, Mexico and inhabits chaparral, grasslands, oak woodlands and pine forests1. Because of the heterogeneous range of E. multicarinata, ecologically mediated processes are likely to be significant contributors to range-wide substructure, although to date no study has explicitly examined the role of biotic and abiotic factors in contributing to population structure. In southern California, the range of E. multicarinata includes the Santa Monica Mountains, a biodiversity hotspot. Within the Santa Monica Mountains, the Stunt Ranch Santa Monica Mountains Reserve encompasses a wide range of habitats, representative of the ecological variation found in the region. This makes Stunt Ranch an ideal site to study the effects of microhabitat variation on fine-scale landscape genomic structure and local adaptation. Here, I propose to examine the effect of micro-scale habitat heterogeneity in Stunt Ranch on patterns of genetic structure and gene flow in Elgaria multicarinata.