CORAL REEF RECOVERY AND RESILIENCE ON PATCH REEFS IN KANEOHE BAY, OAHU
The resilience of coral reef ecosystems has been discussed in the literature for over four decades but has been limited due to the small number of long-term studies that span decades. Increasing frequent and severe disturbances such as major weather events, fresh water kills, and increase in nutrients and sedimentation from surface runoff are causing increased stress to the Kaneohe Bay marine ecosystem. Two events initiated the recovery of coral on patch reefs; the diversion of sewage and associated nutrients outside of the Bay and the disappearance of the native invasive macroalga Dictyosphaeria cavernosa. The resilience, or the recovery of the community, may depend on the ability of remaining corals to vegetatively grow and outcompete macroalgae that once dominated. At the same time, the composition of the macroalgal and herbivore communities that occupy the reefs are critical to the outcome. In the 45 year period from the mid-1960's to 2011, mean coral cover has increased at annual rates of 1 to 4 percent in the intervals following release from competition, comparable to the published rates of recovery observed at other sites following acute disturbances. Five years after the disappearance of D. cavernosa, the two historically dominant reef building corals showed the maximum gains in percent cover. Although the presence and diversity of the other former coral species have decreased over time, the resilience of these remaining species on reef flats and reef slopes throughout the Bay may be key in the future as impacts from global climate change increase.
Sukhraj McCarthy, N., U.S. Fish and Wildlife Service, USA, Nadiera_McCarthy@fws.gov
Location: 313 A
Presentation is given by student: No