In Depth

The GCRMN: Promoting, Utilizing and Sharing Coral Reef Monitoring Data to Better Guide Management

By Wicquart J., Staub F., Dallison T., Allen M., Planes S., Obura D., Logan M., Souter D.

In shallow tropical marine waters, the symbiosis between tiny photosynthetic organisms, named zooxanthellae, and hard corals forms the foundation of one of the largest biologically structures on Earth: coral reefs. Despite representing less than 0.1% of the ocean’s area, these ecosystems provide shelter to about one quarter of all marine species. In addition to this tremendous diversity, coral reefs are crucial to the well-being of many human populations, providing benefits such as fisheries, economic resources from tourism, coastal protection, among others. At the same time, however, coral reefs are highly impacted by human activities, such as overfishing, destruction of habitats or land-based pollution, resulting in large areas of degraded reef that disrupt natural ecosystem processes. In addition to these direct impacts, are the effects of climate change, mostly with the higher risk of more frequent and powerful tropical storms, heat stress and ocean acidification, which can lead to increased destruction to the overall coral reef structure, coral bleaching, and reduced growth rates, respectively.

iStock 117874014To describe the health of coral reefs in this context, and to better understand the driving forces behind ecosystem evolution, it is necessary to put in place an ecological monitoring. To monitor coral reefs, it is common practice to record the composition of hard living corals, alongside other substrates such as algae, and to repeat this measure year after year. The data hence collected can, for example, be utilized to not only understand the impact of a disruptive event (such as bleaching) but also to determine the number of years necessary for the coral cover to recover to levels recorded prior to the disturbance. The data are also particularly useful to evaluate the efficacy of management measures, such as a Marine Protected Areas (MPA). In addition to these local applications, the data acquired by monitoring programs can also be used to warn the civil society and policy makers about the status and trends of coral reefs, and the measures that must be undertaken to preserve their biodiversity and the valuable services that they provide to human populations. However, despite the existence of numerous monitoring programs in coral reefs, the realization of synthetic studies, gathering data acquired at local scales to assess status and trends at larger scales, is often challenging given the large number of organizations and people in charge of monitoring and the variety of methods and data format used.

This issue is one of the reasons which has led to the establishment of the Global Coral Reef Monitoring Network (GCRMN)(GCRMN) in 1995, by the International Coral Reef Initiative (ICRI) (ICRI). The GCRMN relies on a network constituted of different coral reef monitoring actors, including other networks, scientific laboratories, institutional and national programs, researchers and non-governmental organizations. Through its network, the GCRMN aims to provide the best available information on coral reefs, to support their conservation and management. The actions of the GCRMN are built around four major goals.

The first and main goal of the GCRMN is to improve the understanding on the status and trends of coral reefs. Hence, this objective aims to answer two central questions: what is the current status of coral reefs? And how have coral reefs evolved over the last decades? To do so, the GCRMN first aggregate data acquired over the years by the different members of the network and undertake a host of analytical processes to describe temporal trends of coral cover both at regional and global scales. Since its creation, the GCRMN has published a series of regional reports (Caribbean, Western Indian Ocean, East Asian Seas, and Pacific), thematic report and global reports. For the first time in the last thirteen years, the GCRMN will publish a new global report this year, describing the status and trends of coral cover over the last forty years. This study, based on the integration of data from hundreds of monitoring programs, is the first scientific quantitative review realized at this scale. Over the coming years, the GCRMN aims to extend the use of biological indicators used, such as hard coral cover, to other complementary ones (fish abundance and biomass, for example).

iStock 117874027However, while essential, the biological facet alone does not offer a solution to coral reef recovery. An understanding of the human dimensions of coral reefs and social-ecological connections is critical to the long-term conservation and management of these ecosystems. This is important because the ways in which society values coral reefs are diverse and these values form the basis for how people interact with the ecosystem and respond to coral reef issues. As such, a holistic and integrated approach to coral reef monitoring is needed. This is the reason why the second goal of the GCRMN is to focus on social and economic monitoring through the SocMon program program. The core aim of the program is to complement biophysical monitoring by working with local communities to collect data related to the dependence of human populations on coral reef resources, perceptions of resource conditions, threats to marine and coastal resources, and support for marine resource management strategies such as MPAs.

While the first two goals concentrate on description of the different facets of coral reefs and their respective conservation and management, the data that stem from the network’s monitoring programs are also useful for research purposes. This drives the third goal of the GCRMN: to promote the exchange of data and knowledge among the members of the network. Indeed, the use of monitoring data for fundamental research questions may inform management goals. For example, based on data generated by GCRMN members, researchers have discovered that herbivorous fishes promote the recovery of coral cover by feeding on algae, reducing the amount of direct spatial competition with hard corals. In terms of management, this discovery can be transcribed in the limitation of overfishing to promote coral cover recovery following a disturbance.

Finally, the fourth and last goal of the GCRMN is to build human and technical capacity to collect, analyze and report biological, social and economic data on coral reefs. This goal aims to identify areas where new monitoring programs are needed, supporting their implementation by providing adapted methods, recommending good practice on data management and encouraging the analyses and reporting of coral reefs status and trends at regional scales.

This article is part of an online series dedicated to the UN Ocean Decade. One story will be published each week that is related to initiatives, new knowledge, partnerships, or innovative solutions that are relevant to the following seven Ocean Decade outcomes. Access the special digital issue dedicated to the Ocean Decade here.

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