The status and trends of coral reefs around the world – connecting science to conservation action

Long-term ecological monitoring is indispensable to identify and document changes from the triple planetary crisis of climate change, pollution and biodiversity loss. Coral reefs are some of the most biodiverse and most threatened of the Earth’s ecosystems. Accurate information on the status and trends of coral reefs equips decision makers with fundamental information to support the protection of these vital marine ecosystems.

Monitoring of coral reefs is conducted for many purposes, at various temporal resolutions and geographic scales, using various sampling techniques and indicators. The Global Coral Reef Monitoring Network (GCRMN), an operational network of the International Coral Reef Initiative (ICRI), has been producing high-level coral reef status and trend assessments since 1998. The most recent Status of Coral Reefs of the World report, published in 2021, estimated long-term trends of two widely collected indicators for the condition of coral reefs, hard coral cover and cover of macroalgae (both are recommended indicators of healthy coral reefs by ICRI, and ‘Essential Ocean Variables’ as defined by the Global Ocean Observing System). The global dataset spanned from 1978 to 2019 and showed that in most regions of the world, coral cover decreased while algal cover increased, indicating a widespread decline in the condition of coral reefs. The production of the next Status of Coral Reefs of the World report and of status reports from the Pacific and Caribbean regions is currently underway, and an overview of key findings will be presented.

It is challenging to combine disparate coral reef monitoring data for regional and global-scale assessments because of differences in sampling methods, sample sizes, lack of data standards and biases or gaps in the representativeness across geographic and temporal scales or for certain indicators. Notwithstanding these challenges, the value of regular quantitative analyses of such integrated datasets is immense. Ecosystem trends detected at regional and global scales provide a powerful basis to foster collaborative partnerships between scientists, conservation managers and practitioners, to understand key drivers and ecological dynamics for guiding and supporting evidence-based policies, and to equip Governments with essential mechanisms to implement and monitor their progress towards national and international targets and commitments.

The collective experience, capability and willingness to share knowledge and data under the umbrella of the GCRMN has also provided important learnings to facilitate more standardisation and interoperability of coral reef monitoring protocols, use of new technologies, improved data management and analysis, and capability-building of the next generation of coral reef monitors. This presentation will highlight some of these developments and how the GCRMN contributes to SDG14 by leveraging innovative tools and technologies and providing actionable knowledge on coral reef status and trends at different scales and to different audiences.