Strengthening resilience potential assessments for coral reef management

Abstract

The persistence of diverse yet threatened ecosystems like coral reefs will require urgent action underpinned by effective assessments of resilience. Resilience potential assessments are commonly used to identify coral reefs likely to be more resilient to disturbances, based on indicators of state and function. Assessments are intended to support decision-making, therefore, using principles from decision-science and indicator design theory, we evaluated the selection, design and analysis of indicators from 68 resilience potential assessments conducted between 2008 and 2022. These principles include justifying and testing indicators and aggregation approaches, representing key parts of the ecosystem, considering uncertainty and meaningful normalisation of indicators. Although a broad range of indicators were typically evaluated, assessments rarely present structured processes to guide and justify indicator selection, such as selection criteria and conceptual models of ecosystem function. We also found that certain key ecosystem components that confer resilience were represented by indicators in almost all assessments, such as corals, herbivory, competition and reef structure. Other factors were rarely considered, such as abundance and diversity of key fish trophic groups other than herbivores, for example groupers and corallivores, other aspects of biodiversity and competitive interactions with corals. Reference points used to translate variables into resilience indicators were typically derived from the data, such as the highest indicator value of assessed sites. Ecologically meaningful thresholds, such as collapse or historic levels, were used less often as references. In most cases, indicators were not tested or validated against independent data, uncertainties were not presented, and there was a tendency to simplify results into composite indices to rank sites, without justifying aggregation methods. Despite resource constraints, most resilience potential assessments collect quantitative data that are useful for coral reef management. However, the shortcomings identified can make indicator interpretation difficult, limiting the capacity to predict the resilience of the system and support decisions. Implementation of robust approaches drawn from indicator design and selection theory can help strengthen resilience potential assessments of coral reefs and other ecosystems, ultimately improving the prospects of conservation.