Floristic classification is not a predictor of species-specific evolutionary patterns

Abstract

Abstract The relationship between intra-specific and inter-specific patterns and processes over evolutionary time is key to ecological investigations. We examine this relationship from a novel perspective, focussing on the association between floristic classifications, a summary of inter-specific processes, and intra-specific genetic structuring. Applying an innovative, multispecies, and standardised population genomic approach we test the relationship between vegetation mapping schemes and landscape-level estimates of gene flow across a large, environmentally heterogenous region. We show that intra-specific genetic variation shows limited correspondence to vegetation classifications and is better explained by distance between sampled populations and the location of biogeographical features which limit gene flow. However, vegetation classification schemes with contiguous mapping classes were more predictive of genetic lineages than geographically non-contiguous schemes. The size of mapping units was found to be important, as most local vegetation types contained only single intra-specific genetic lineages, while these genetic lineages spanned hundreds of km’s across multiple vegetation types. We conclude that floristic classifications are not closely correlated with intra-specific genetic patterns, showing that intra-specific genetic processes are independent of inter-specific floristic assembly processes. This study also showcases the depth of understanding that can be developed using large, multispecies genetic datasets.