Multiple lines of genetic inquiry reveal effects of local and landscape factors on an amphibian metapopulation

Abstract

Abstract

Context A central tenet of landscape ecology is that both characteristics of patches and the matrix between them influence functional connectivity. Landscape genetics seeks to evaluate functional connectivity by determining the role of spatial processes in the distribution of genetic diversity on the landscape. However, landscape genetics studies often consider only the landscape matrix, ignoring patch-level characteristics, and possibly missing significant drivers of functional connectivity.

Objectives (1) Evaluate drivers of functional connectivity for an amphibian metapopulation, and (2) determine whether local characteristics are as important as landscape features to functional connectivity of this species.

Methods We used gravity models to evaluate the evidence for hypothesized drivers of functional connectivity for Dryophytes wrightorum that included both local and landscape attributes and a novel combination of methods of genetic inquiry: landscape genetics and environmental DNA (eDNA). Hypothesized drivers of connectivity included effects of hydrology, canopy cover, and species interactions.

Results Evidence weights indicated that stream networks were the most likely driver of functional connectivity, and connectivity along stream networks was positively correlated with gene flow. We also found a strong correlation between abundance of D. wrightorum from eDNA data and effective population size estimates from microsatellite data.

Conclusions We found evidence that functional connectivity of D. wrightorum was strongly driven by stream networks, despite considering multiple local and landscape processes. This suggests that management of this species focused on landscape hydrologic connectivity as gene flow corridors while maintaining current local management action is likely to have a positive effect on species conservation.