OCE-PRF: Investigating coral demographic processes to understand how local conditions interact with climate change to influence coral recovery trajectories

Arizona State University, Scottsdale AZ

Investigators

Abstract

Coral reefs are among the most imperiled ecosystems, threatened by global climate change and local stressors such as overfishing and pollution. Global climate change threatens coral reefs because warm water events (known as ‘marine heatwaves’) trigger coral bleaching and mass mortality. Local conditions on coral reefs, such as pollution or algal overgrowth that compete with corals, can intensify coral mortality following bleaching events. However, we do not understand whether these local conditions on coral reefs also influence long-term coral recovery after bleaching events. This research addresses this knowledge gap and provides results to inform efficient management actions to lessen the impacts of local stressors on reefs in the face of climate change. Unlike global climate change, local stressors to coral reefs can be managed by individual communities and countries. Much of this work focuses on reefs in Hawaii and provides direct societal benefits to communities in Hawaii. In addition, this project supports an early-career researcher and provides research opportunities and training in quantitative tools and computer programming skills for students from underrepresented groups in STEM. These are fundamental skills for innovative research across scientific disciplines and STEM careers. The degree to which local conditions influence coral recovery after bleaching events is debated, partly because we have a poor understanding of how demographic processes in corals drive recovery or lack thereof. This work uses several existing datasets and a multi-tiered modeling approach to study coral demographic processes to understand how local conditions interact with climate change to influence coral recovery trajectories. This work uses a time series of coral size-frequency data across four regions in the Pacific to assess coral demographic rates (colony growth and recruitment) following regional bleaching events and evaluate the relative importance of those demographic processes in driving recovery dynamics. Data from Hawaiian reefs are used to build a series of structural equation models to evaluate the impact of local stressors (fishing pressure and nutrient pollution) on coral demographic rates and their relationship to reef recovery trajectories. Additionally, the principal investigator plans to use those models as a foundation to forecast how reducing local stressors may or may not enhance coral recovery rates in Hawaii. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.