Microbes, mutualism, and range margins: testing the fitness consequences of soil microbial communities across and beyond a native plant's range

Benning, John W.; Moeller, David A.

doi:10.1111/nph.17102

Abstract Replicability of divergence after contact is a poorly characterized process, particularly in the contexts of phylogeography and postglacial range dynamics within species. Using contact zones located at the leading‐, mid‐ and rear‐edges of a species' range, we examined variation in outcomes to contact between divergent lineages ofCampanula americana. We investigated whether contact zones vary in quantity and directionality of gene flow, how phylogeographic structure differs between contact zones, and how historic range dynamics may affect outcomes to contact. We found that all contact zones formed at similar times via primary contact yet detected significant admixture in only the rear‐edge (RE) contact zone. In the northern leading‐edge contact zone and the mid‐range Virginia contact zone, gene flow was minimal and asymmetric. In the southern RE contact zone, gene flow was strong and symmetric. Asymmetric admixture in the leading‐edge and Virginia contact zones matches the directionality of a known cosmopolitan cytonuclear incompatibility between lineages ofC. americana. Our results emphasize the dependence of speciation processes on phylogeographic structure, evolutionary history and range dynamics.

More Like this