The relationship between phylogeny, range size, niche breadth and niche overlap in European orchids (Orchidaceae)
Hans Jacquemyn, Ben De Coensel, Alexandra Evans, Deyi Wang, Vincent S. F. T. Merckx
Abstract
Abstract Aim Understanding the various factors that contribute to the distribution and geographical ranges of plant and animal species has been a central issue in ecology, evolution and biogeography for more than two centuries. In this study, we investigated whether (i) niche breadth is phylogenetically conserved, (ii) niche overlap is negatively correlated with orchid evolutionary distance, and (iii) more recently diverged sister species show more niche overlap compared to older sister species. Location Europe. Taxon Orchids (Orchidaceae). Methods Ecological niche models were created for 107 European orchid species distributed across 17 genera using occurrence and environmental data. A time‐calibrated phylogeny was reconstructed and the phylogenetic signal for range size and niche breadth was estimated. Phylogenetic distances among species were calculated to test the hypothesis that niche overlap is explained by evolutionary history. Finally, we investigated whether the divergence age of sister taxa was negatively related to niche overlap. Results Range size and niche breadth in both geographical and environmental space varied by more than three orders of magnitude and were strongly correlated with each other. We did not find strong evidence for phylogenetic conservatism in range size, niche breadth and niche overlap. However, sister taxa pairs with older divergence age showed less overlap in their environmental niche compared to more recently diverged sister taxa. Main Conclusions We conclude that orchid species that have broader ecological niches tend to display larger range sizes. Our results further show that the current distribution of orchid species across the European continent is best explained by recent speciation events and relative rapid adaptation to local environmental conditions, while deep‐level phylogenetic relationships are not correlated with ecological niche breadth.