Prioritizing reef resilience through spatial planning following a mass coral bleaching event

Following the recent 2014–2017 global coral bleaching event, managers are seeking interventions to promote long-term resilience beyond monitoring coral decline. Here, we applied a spatial approach to investigate one potential intervention, mapping areas where local management could build coral reef resilience using herbivore management. Although herbivore management is a top recommendation in resilience-based management, site-specific attributes are thought to affect its success, and thus strategizing placement and design of these areas are crucial. Using Marxan, we mapped and prioritized potential Herbivore Management Areas (HMAs), where herbivores are protected but other types of fishing are allowed, in the main Hawaiian Islands. Through four scenarios, we found multiple hotspots along the west coast of Hawai‘i Island and around the islands of Moloka‘i, Lana‘i, Maui, and Kaho‘olawe where HMAs may have the best chance for success based on habitat, ecologically critical areas, life history, and social considerations. We further analyzed top results and found that a subset of characteristics including habitat types, biomass of herbivore functional groups, and temperature variability were significantly different from surrounding areas and thus contain potential drivers for selection. This unique approach can serve as an example for coral reef management in Hawai‘i, on other Pacific Islands, and beyond, as it provides practical guidance on how to apply a resilience-building tool at a local level, incorporating site-specific biological and socioeconomic considerations.