A Comparison of Macroinfaunal Community Structure between Artificial Concrete Boulder Reefs and Adjacent Natural Reefs in Broward County, Florida

摘要

Relatively little is known about either the biological (i.e., predation) or physical (i.e., current, sedimentation) effects that artificial reefs may have on surrounding benthic infaunal communities. Following deployment of artificial reefs (concrete boulders) between the first and second reefs off Fort Lauderdale, Florida, on 30 October 2009, sediment cores were taken at 4 distances along three replicate 10-m transects on 13 and 26 September 2013, and 24 and 25 May 2014 at each of four artificial reef sites and four of their adjacent natural reef sites using SCUBA. Infauna (u3e0.5mm) were extracted from the sediment and identified to the lowest possible taxonomic level. Statistical analysis (PRIMER, PERMANOVA, SIMPER) focused on four main variables: type of reef, year, site, and distance. Type of reef, year, and site was significantly different between samples, while distance did not affect density. There is a clear separation of communities between the artificial and natural reefs. From 2013 to 2014, a slight shift occurred between communities suggesting the artificial reef community composition became slightly more similar to the natural reef. All four artifical reef sites were more taxonomically distinct at the phylum and class level then the natural reef, which had higher diversity, higher species richness and more low-density taxa. This two year study provides insight on infauna communities four and five years out from deployment, but follow up monitoring in 3-5 years could shed light on whether these patterns of shift to more similar assemblages between reefs will continue as the artificial reef matures. Environmental data collection including longer time-series datasets, longer transects, and physical and geological data could provide more knowledge of how the artificial reef infaunal communities are changing over time.