Questions The extent to which metacommunities exhibit species with metapopulation dynamics is poorly understood. We investigate this issue within sandstone glade plant communities scattered across an upland hardwood forest. We investigate the life forms of metapopulation species and relationships between taxonomic, phylogenetic, and functional diversity, composition, and environmental factors.

Locations Twenty-three sandstone outcrop communities in southern Illinois, USA.

Methods Following vegetation surveys, species exhibiting metapopulations dynamics were identified and compared to all species based on origin, growth form, and lifecycle. Cohesion, turnover, and boundary clumping were utilized to determine metacommunity structure. Correlations evaluated associations between site-based variables, and regressions evaluated associations between diversity indices. Multivariate analyses compared sites to determine which variables contributed to compositional differences.

Results Twenty of 130 species exhibited metapopulations dynamics and were usually annual or biennial exotics. Metacommunity elements indicated a Clementsian metacommunity, where metapopulation species were subordinate as opposed to dominant or transient. The largest sites were the most regularly shaped, but not the most diverse. Species richness and metapopulation species determined phylogenetic and functional diversity, but largely non-standardized measures of diversity, indicating independence between types of diversity. Multivariate analyses showed that diversity metrics explained community composition differences, where more species-rich sites with more metapopulation species were also more phylogenetically and functional diverse.

Conclusions:  Sandstone glade communities exhibited diverse plant communities, where phylogenetic and functional diversity were driven by both total and metapopulation species independently. The metapopulation species were usually short-lived and exotic species with their low number likely constrained via dispersal limitations. The communities exhibited Clementsian metacommunity structure indicating predictable community assemblages. Functional traits indicated that these communities include species adapted to xeric, substrate-poor conditions.