Patterns of recruitment and succession on ceramic settlement panels were
examined in a subtidal marine community in eastern Australia to determine
whether competition for settlement space with temperate biota was a factor
potentially limiting the development of coral communities in a subtropical
location. Replicate settlement panels were installed at Split Solitary Island
(30˚S) in November 1992 and were destructively sampled after 1, 3, 5, 7,
10, 12, 16 and 29 months. Species richness and community structure data were
analysed by non-parametric multivariate analysis. Space on panel surfaces was
rapidly occupied; the upper surfaces by algae and the lower surfaces by
bryozoans, ascidians and sponges, with a divergence of community structure
over time. Of the 228 coral recruits identified on the panels, 98% were
recorded on the upper surface of panels, in contrast to studies at most
tropical sites where corals recruit predominantly to lower surfaces. Owing to
the rapid settlement of other biota, free space for coral settlement was
limited and this may account for the low coral recruitment rate recorded. High
post-settlement mortality (>94%) of coral recruits over a 3-month
period indicated the significance of post-settlement factors in accounting for
low recruitment in settlement-panel studies.