Detecting the phylogenetic signal of glacial refugia in a bryodiversity hotspot outside the tropics

Introduction Glacial refugia have likely been important in shaping diversity gradients outside the tropics. Many taxa that high extratropical present day, such as mosses, may persisted glacial refugia. However, biogeographical histories of most species within remain unclear. Location Haida Gwaii archipelago, north-west coast British Columbia, Canada. Taxa Bryophyta (mosses). Methods We reconstructed regional phylogeny mosses Gwaii, a putative refugium and ‘hotspot’ moss diversity, used phylogenetic comparative methods to examine macroecological imprint on geographic range structure attributes present-day assemblages. Results found many widespread, but disjunct, distributions, with few close relatives islands. suggest these features reflect history, whereby represent isolated populations previously more widespread diversified elsewhere. also observed evidence for overdispersion high-elevation habitats, which best match climatic regime historical refugium. Our results are consistent filtering evolutionarily distinct relicts contrasts markedly patterns clustering across other non-refugial habitat types. Main conclusions The islands an hotspot bryophyte diversity. study illustrates how shaped by highlights importance maintaining