| Marine protected areas (MPAs) represent a popular, but often controversial, management option for the conservation of dwindling reef fish populations worldwide. Questions concerning appropriate design criteria for MPAs lie at the center of the controversy, and reflect a need to better understand the influence of landscape structure of coral reef ecosystems (e.g., size, shape, context of habitat patches) on reef fish assemblage structure. I explored the utility of various landscape metrics in predicting reef fish assemblage structure and found that reef context explained considerable variation in the several reef fish parameters. Specifically, I found that particular groups of fishes were associated with particular types of habitat. Based on these results, I designed a new study in the U.S. Virgin Islands to determine examine whether functional habitat linkages between reef and seagrass habitat patches were detectable at a landscape-scale. Consistent with predictions, entire assemblage level parameters and abundances and species richness of mobile invertebrate feeders, haemulids, lutjanids, and epinephelids were each significantly greater at reefs with seagrass within 1 kilometer of the study reef patch. The generality of reef context as a predictor of reef fish assemblage structure was then tested in the Florida Keys National Marine Sanctuary. Though reef context was significant in both systems, the particular habitat type responsible for the reef fish---habitat relationships differed between the coral reef landscapes. Seagrass was a strong predictor of abundances and species richness of mobile invertebrate feeders, haemulids, and lutjanids in the US Virgin Islands, but was not a predictor of these same fishes in Florida. Thus, the processes that structure reef fish communities appear to respond to variation in the landscape structure of these coral reef environments. These results are relevant to marine protected areas design, since they suggest that general design rules do not necessarily apply across systems. Rather, comparative studies are critical for developing the universal design principles to locate marine protected areas that meet their conservation and/or fisheries objectives. |
