Spatial phylogenetics of the North American moss flora

Aim: We documented patterns of phylogenetic diversity (PD) and phylogenetic endemism (PE) in the moss flora of North America, determined how environmental variables explain these patterns, compared patterns in mosses to known patterns in angiosperms, and explored how patterns driven by subclades might conflict with patterns driven by other subclades. Location: North America north of Mexico Taxon: Mosses (Bryophyta) Methods: A maximum-likelihood tree inferred from publicly available sequence data, and locality data from ca. 7.5 × 105 herbarium specimens, were combined to build a dataset of 935 species (representing ca. 67% of the known moss flora). Spatial randomization procedures were used to find significance levels of PD and relative phylogenetic diversity (RPD) for the full dataset and three major subclades, as well as to carry out a Categorical Analysis of Neo- and Paleo-Endemism (CANAPE). Range weighted turnover in both species and PE was used to identify phytogeographic regions across the continent. Ordinations of environmental data were used to determine the distribution of PD, RPD, and phytogeographic regions within environmental space. Results of this study were compared to known patterns of phylodiversity in angiosperms. Results: Phylodiversity is distributed non-randomly. Some patterns, for example long branches in the southeastern US, are consistent with angiosperms, however there are strong contrasts as well. Overall patterns of PD and RPD are strongly influenced by different phylogenetic scales within mosses, indicating that signal from one clade can obscure patterns in others. Three primary phytogeographic zones are defined by both differing geological histories and differing current abiotic conditions Phytogeographic regions, PD, and RPD are all aligned with environmental variables. Main conclusions: There is evidence for both ecological and historical factors in shaping the moss flora of North America, and biogeographic differences between angiosperms and mosses appear to align with important life-history differences between the two groups