Great Barrier Reef recovery through multiple interventions

Abstract

The decline of coral cover on Australia's Great Barrier Reef (GBR) has largely been attributed to the cumulative pressures of tropical cyclones, temperature-induced coral bleaching, and predation by crown-of-thorns starfish (CoTS). In such a complex system, the effectiveness of any management intervention will become apparent only over decadal time scales. Systems modeling approaches are therefore essential to formulating and testing alternative management strategies. For a network of reefs, we developed a metacommunity model that incorporated the cumulative pressures of tropical cyclones, coral bleaching, predation, and competition between corals. We then tested the response of coral cover to management interventions including catchment restoration to reduce discharge onto the reef during cyclone-induced flood events and enhanced protection of trophic networks supporting predation of CoTS. Model results showed good agreement with long-term monitoring of the GBR, including cyclical outbreaks of CoTS driven by predator-prey dynamics on the network of reefs. Testing of intervention strategies showed that catchment restoration would likely improve coral cover. However, strategies that combined catchment restoration with enhanced CoTS predation were far more effective than catchment restoration alone.

Keywords: Acanthaster planci; conectividad de arrecifes; coral; crown-of-thorns starfish; cumulative impacts; ecosystem model; estrella de mar corona de espinas; impactos acumulativos; metacommunity model; modelo de ecosistema; modelo de metacomunidad; reef connectivity; 棘冠海星Acanthaster planci, 珊瑚, 珊瑚礁连接度, 累积影响, 生态系统模型, 集合群落模型.