Epiphytic bryophyte communities of Prunus lusitanica Iberian forests: biogeographic islands shaped by regional climates

Epiphytic communities of Iberian forests remain partly unknown and most studies have focused on the dominant oak forests. We provide a comprehensive analysis and interpretation of the epiphytic bryophyte communities of forests dominated by the Tertiary relict evergreen cherry Prunus lusitanica. This type of forest, scattered in the western and northern half of the Iberian Peninsula, harbours a noticeable richness of epiphytic bryophytes, including an outstanding number of liverwort species. Their floristic composition varies markedly across the Peninsula yet is driven by the main climate patterns prevailing in the area. Multivariate analyses (TWINSPAN, CCA) render two main groups of epiphytic communities with their respective indicator species. Both groups share a high proportion of non-Mediterranean species, a circumstance that is most remarkable in the forests that fall within the Mediterranean Region, which could be considered as ecological refuges or biogeographic islands.