Effects of marine protected areas on benthic community structure and ecological processes on coral reefs in Hawai'i.

摘要

Despite a wealth of information on the effects of Marine Protected Areas (MPAs), the direct influence of marine protection on specifically coral communities has yet to be fully established. The goal of my dissertation research was to determine whether, in the Main Hawaiian Islands, MPAs influence coral communities and ecological processes with direct and indirect effects to these. My specific research objectives were to determine the effects of MPAs on: (1) the composition of the benthic community; (2) grazing by parrotfishes; (3) predation on coral by fishes; and (4) the balance between bioerosion and accretion of the reef framework. While I found a trend of greater herbivorous fish populations at sites with greater levels of marine protection, this was not associated with a predictable benthic community composition such as low macro- or filamentous turf algal cover, high crustose coralline algal cover and coral cover, or low densities of Tripneustes gratilla and Echinometra mathaei urchins My grazing study demonstrated that algal reduction rates by parrotfishes were positively related to parrotfish biomass, and were proportionately greater per unit biomass for large compared to small parrotfishes. I found fish predation on coral by Arothron meleagris and Cantherhines dumerilli to be prevalent across study sites, and focused on the most common Hawaiian coral species. Predation by A. meleagris on Porites compressa appeared to have little effect when the coral was abundant and when lesions healed efficiently, but limited P. compressa population growth once corals become sparse, and/or the size of corals become very small. The carbonate budget I developed, while simplified, showed study reefs to have net accretion, and this to be driven primarily by growth of the coral community.