MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps14400

ABSTRACT: Replenishment of species within a community is largely determined by early life history dynamics, yet the relative contributions of settlement versus post-settlement processes in establishing coral community structure are not well understood. Here, we examine the effect of larval density, number of settlers and presence of conspecific adults on settlement and post-settlement success for three broadcast-spawning scleractinian corals under aquarium conditions. We find that settlement and post-settlement survival are dependent on larval or settler densities but with contrasting effects among the studied coral species. Settlement of Anacropora spinosa larvae was inversely density-dependent, while settlement of Acropora gemmifera and Acropora digitifera larvae was density-independent. Anacropora spinosa had high post-settlement survivorship, while Acropora digitifera underwent significant density-dependent post-settlement mortality within 14 days after settlement. For all species, settler spatial patterns were under-dispersed, with the probability of contact between settlers positively correlated to initial settler numbers and the extent of under-dispersion showed little change over time. The presence of conspecific adults led to a decrease in larval settlement of A. spinosa and A. gemmifera but had only a weak influence on settler survival for A. spinosa. These data indicate, in an experimental setting, that settlement success of larvae can be reduced when near to a conspecific adult and may be mediated by a waterborne agent. Overall, our results demonstrate the potential for self-limitation via conspecific larval-adult interactions and facilitation among early life stages of a cohort.