High-latitude Acropora cervicornis thickets off Fort Lauderdale, Florida, USA

Baseline studies conducted in 1998 document the presence of robust, non-reef-building Acropora cervicornis thickets in shallow (3-7 m depth), near-shore waters off the coast of Fort Lauderdale, Florida, USA. These thickets thrive in a high-latitude environment, the northernmost in the continental USA, in the midst of potential anthropogenic stressors. Within thickets, the spatial variation in mean percent coral cover, macroalgal cover, scleractinian species richness, density of A. cervicornis juveniles, and the density and size of A. cervicornis colonies and fragments were recorded. Thicket size ranged between similar to0.1 and 0.8 ha and mean coral cover varied between similar to5 and 28%, with A. cervicornis accounting for similar to87-97% of all scleractinians. Mean A. cervicornis colony and fragment densities per thicket were 1.3-3.3 colonies m(-2) and 0.7-2.8 fragments m(-2), respectively. Recruit densities varied between 0 and 1 ind. m(-2). White band disease was detected at all thickets, with a mean A. cervicornis colony surface area affected of 1.8%. For all thickets, densities of the corallivorous polychaete Hermodice carunculata ranged between similar to18 and 86 ind. ha(-1), with predation scars affecting <0.2% of the A. cervicornis cover. These flourishing A. cervicornis thickets off Fort Lauderdale provide an interesting counterpoint to the declining and disease-stricken A. cervicornis populations reported in the Florida Keys and wider Caribbean.