CLIMATE VARIABILITY AND THE RESILIENCE OF LOW DIVERSITY CORAL COMMUNITIES TO BLEACHING IN THE GILBERT ISLANDS, KIRIBATI
Ocean warming due to climate change threatens to cause frequent coral bleaching and degrade coral reefs across the Pacific. Recent research has suggested that past temperature experience, including exposure to variable temperatures and/or frequent heat stress, confer greater resilience to climate change. The central equatorial Pacific, where the El Niño / Southern Oscillation, drives year-to-year shifts in current strength, current direction and consequently ocean temperatures, is an ideal natural laboratory for evaluating the influence of past sea surface temperatures (SST) on the susceptibility of individual corals and coral communities to heat stress. This presentation describes changes in the coral community over the past decade, including multiple El Nino-driven heat stress events, in the little-studied Gilbert Islands of Kiribati. Changes in benthic cover, coral size distribution as well as the bleaching index (for the 2009-2010 El Niño) are contrasted between a matrix of sites exposed to different levels of SST variability and human disturbance across four atolls. Spatial analysis shows that patterns in coral bleaching are best correlated with light and the coefficient of variation of past sea surface temperatures, rather the magnitude of heat stress during the El Niño event (e.g. degree heating weeks). The long-term data indicates that reefs subject to the combination of high human disturbance and high temperature variability are the most resilient to heat stress, due to the presence, and continued expansion, of the “weedy” species Porites rus.
Cannon, S. E., University of British Columbia, Canada, email@example.com
Donner, S., University of British Columbia, Canada, firstname.lastname@example.org
Time: 18:15 - 19:45
Location: Poster/Exhibit Hall
Presentation is given by student: Yes