Assessing changes to ecosystem service values at large geographic scale: A case study for Australia's Great Barrier Reef

Climate change is impacting numerous natural world heritage sites – the Great Barrier Reef (GBR) being just one. There are calls for interventions to help sustain reef values in the face of climate change and while there are numerous techniques for assessing impacts on non-market values, most struggle to generate robust estimates for large and complex systems. This complicates the assessment of potential benefits of reef interventions. Focusing on corals in the GBR, we develop and apply a systematic, evaluative framework that combines insights from a coral-reef simulation model with those from research on reef-related ecosystem services (ES). We estimate the market and non-market benefits of complete control of coral-eating crown-of-thorns starfish (CoTS) and global climate mitigation. By comparing the present value of ES with and without interventions, we can assess their potential benefits: between $5b and $28.5b depending on intervention and discount rate. Our empirical insights are specifically relevant to the GBR. Our generic approach to assessing the potential value of CoTS control at large scale and in data/knowledge-poor environments can be developed further and adapted to other interventions.