Beyond Coral Cover: A framework for assessing the condition of coral reef habitats and informing conservation targets

Abstract

The goal of ecosystem management is to maintain healthy and resilient ecosystems over time. These attributes can be summarised under a general term widely used in management plans: ecosystem condition, defined as the overall quality of an ecosystem relative to a desired or reference state. However, measuring and monitoring ecosystem condition remains a challenge. Monitoring ecosystem condition requires a suite of ecological indicators that simultaneously capture the complexity and variability of ecological processes, while being informative and usable in management and decision-making contexts. Such indicators need to be holistic, measurable, sensitive and scalable. Here we outline a resilience-based monitoring framework for coral reefs that consolidates monitoring data and research insights into a relevant, integrated format. The framework includes indicators of ecosystem state (coral cover) and key processes (represented by recovery performance, macroalgae prevalence, community composition, and coral juvenile density). Indicators are generated and scaled from monitoring data by applying explicit, reef-specific thresholds, providing a simple but comprehensive set of ecosystem condition values. Using cases from the Great Barrier Reef, we demonstrate how the framework integrates these indicators for detailed assessments of reef habitat condition and its potential role in management. Based on these case studies, we discuss important considerations for applying this framework worldwide, acknowledging current limitations related to data availability, resolution, and the length of time series.