Succession, space and coral recruitment in a subtropical fouling community

Patterns of recruitment and succession on ceramic settlement panels were ex amined in a subtidal marine community in eastern Australia to determine whe ther competition for settlement space with temperate biota was a factor pot entially limiting the development of coral communities in a subtropical loc ation. Replicate settlement panels were installed at Split Solitary Island (30 degrees S) in November 1992 and were destructively sampled after 1, 3, 5, 7, 10, 12, 16 and 29 months. Species richness and community structure da ta were analysed by non-parametric multivariate analysis. Space on panel su rfaces was rapidly occupied; the upper surfaces by algae and the lower surf aces by bryozoans, ascidians and sponges, with a divergence of community st ructure 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 mos t tropical sites where corals recruit predominantly to lower surfaces. Owin g to the rapid settlement of other biota, free space for coral settlement w as limited and this may account for the low coral recruitment rate recorded . High post-settlement mortality (>94%) of coral recruits over a 3-month pe riod indicated the significance of post-settlement factors in accounting fo r low recruitment in settlement-panel studies.