Genetic, Morphological, and Environmental Differentiation of an Arid-Adapted Oak with a Disjunct Distribution

The patterns of genetic and morphological diversity a widespread species can be influenced by environmental heterogeneity the degree connectivity across its geographic distribution. Here, we studied Quercus havardii Rydb., uniquely adapted desert oak endemic to Southwest region United States, using genetic, morphometric, datasets over various scales quantify differentiation understand forces influencing population divergence. First, quantified variation analyzing 10 eastern 13 western populations from disjunct distribution Q. 11 microsatellite loci, 17 variables, 19 bioclimatic variables. We then used regressions examine local regional correlations climate with variation. found strong differences corresponding large-scale disjunction populations. Additionally, had higher lower relatedness than Levels in were primarily associated precipitation seasonality, while levels daily temperature fluctuations winter precipitation. Finally, little no observed niche overlap between regions. Our results suggest that likely represent two distinct taxonomic entities, each unique set climatic variables potentially diversity.