Assembly history matters for metacommunity

While previous theoretical and experimental work have demonstrated the importance of the history of community assembly for generating alternative stable community states, whether assembly history matters for metacommunity remains empirically unexplored. We constructed laboratory microbial metacommunities to investigate the effects of dispersal among local communities and history in which species colonize local communities on both local- and meta-community patterns. Each metacommunity consisted of five local communities each experiencing a distinct colonization sequence randomly assembled from a pool of ten bacterivorous protozoan species. Allowing dispersal among local communities reduced β- and γ-diversity, but had no effect on overall α-diversity; further increasing the rate of dispersal led to no further changes in diversity at all scales. Nevertheless, certain colonization sequences produced distinct local communities that can be clearly distinguished from other local communities, regardless of the level of dispersal. Our results suggest that dispersal may not necessarily diminish the role of assembly history in structuring local communities and that differences in assembly history may still lead to alternative community states within metacommunities.