Advances in coral reef restoration in the Mexican Pacific: active interventions and scaling approaches

Abstract

Introduction: Coral reefs face escalating threats from the synergic effects of natural and anthropogenic stressors, challenging traditional conservation strategies and prompting the emergence of direct intervention approaches for coral reef restoration. Coral reef restoration efforts in the Eastern Tropical Pacific, particularly in the Mexican Pacific (MP), face unique challenges due to environmental factors and infrequent interventions. Objective: This review examines procedural aspects and the effectiveness of active restoration efforts along MP reefs, emphasizing coral gardening's adaptability, assisted propagation's affordability, artificial substrata's potential, micro-fragmentation's promise, and ecological engineering approaches. Results: From 2010 to 2023, restoration interventions in the MP increased by 180%, primarily targeting the branching coral genus Pocillopora, using asexual recruits and micro-fragments. Most studies indicate regional and local environmental variability has influenced survival, growth rates, and self-attachment success. While early intervention assessments reported high fragment survival rates (>60%) and significant growth (up to a two-fold increase), there is now a shift toward evaluating ecological metrics such as coral cover, species assemblages, carbonate production, and overall ecosystem functionality, which are currently under assessment in the region. Conclusions: Restoration programs should be tailored to site-specific characteristics. Their effectiveness depends on biological and ecological metrics, but comprehensive evaluations must also incorporate social and economic factors. Achieving lasting success requires transitioning to cost-effective, scalable, and sustainable restoration programs while addressing the root causes of reef decline (environmental degradation) and enhancing coral resilience.