Using successional drivers to understand spatiotemporal dynamics in intertidal mudflat communities

Elucidating factors ("drivers") that influence succession after disturbance can explain ecological phenomena, including why communities vary spatiotemporally. To gain insight on drivers related to habitat availability, species availability, and species performance during succession, we conducted two field experiments on infaunal communities in intertidal mudflats, one on each of the Atlantic and Pacific coasts of Canada, that had disturbances of different type, size, and frequency. Related to habitat availability drivers, we observed that disturbance type and size, which differed between experiments, did not change end patterns of succession; however, disturbance frequency, directly assessed in one experiment, did. Dispersal of species from surrounding mudflat and water column (species availability) was the primary driver of succession, whereas local interactions between species after colonization (species performance drivers) did not have a detectable effect. We suggested that ample space and resources diffused competition and predation effects, and so species replacements did not occur in our systems, resulting in a lack of "traditional" successional dynamics as observed in other ecosystems. Our findings that community composition in intertidal mudflats is strongly influenced by species availability on two different coasts suggest that this driver may be key to variation in intertidal mudflat communities elsewhere.