Does colonization contribute to spatial patterns of common invertebrates in coralline algal turf?

The potential of colonization to contribute to the spatial patterns of six common invertebrates in coralline algal turf was investigated on a rocky shore near Sydney, Australia. The species, which included two amphipods (Elasmopus warra,Hyalespp.), a small bivalve (Lasaea australis), a fly larva (Limonia marina), and two microgastropods (Amphithalamus incidataandEatoniella atropurpurea), had a range of dispersal modes (larval dispersal, crawling, swimming, rafting, and passive transport). Field sampling between May 1997 and November 1999 demonstrated that the amphipods were more abundant in low-shore areas, the fly larvae and bivalves were more abundant in mid-shore areas, and the abundances of gastropods did not vary with tidal height. Furthermore, abundances of all species varied among patches separated by tens of metres at one time or another. To test whether rates of colonization could contribute to established patterns of abundance, habitat mimics were deployed for 2-week periods. The supply of new individuals matched long-term patterns of abundance at different tidal heights forE. warraandL. marina. Colonization rates also differed among patches separated by tens of metres for three of the six species. Overall, there was little evidence to suggest that common species in coralline turf are limited by colonization on local scales, regardless of their major mode of dispersal. However, the potential for colonization to determine patterns of abundance varied from species to species. [ABSTRACT FROM AUTHOR]