LOCAL-CONTROL OF RECRUITMENT IN AN EPIFAUNAL COMMUNITY AND THE CONSEQUENCES TO COLONIZATION PROCESSES

We found that recruitment, abundance, and dominance within two subtida l epifaunal communities in southern New England, USA persist year afte r year over large areas of the bottom. This long-term persistence in b oth dominance and recruitment is not expected in such an open system w ith disturbances continually creating open patches for recruiting larv ae whose identity and abundances change both temporally and spatially. We suggest that the persistence results from strong local control of recruitment that overrides any variability in larval production and di spersal of species from outside a site. Although local dynamics that c ontrol persistence involve all life-stages, we found that intense pred ation on post-settlement individuals has drastic effects. This predati on alters the relative abundances of recruits, prevents the invasion o f some species, and allows others to dominate. In addition, epifaunal communities are often dominated by species producing short-lived, poor ly dispersed larvae. The continued local recruitment of these species at a given site can contribute to the long-term persistence of dominan ts already present. Based on these observations, we suggest that a sys tem of locally reproducing, self-sustaining populations coupled with s trong local environmental differences (e.g. predation on recruits) lim iting: the invasion of other species may better represent some subtida l benthic communities than a system with widely-dispersed larvae, recr uitment dominated by production outside the community, disturbance cre ating continual changes in dominance, and little long-term persistence .