Corals at the edge of environmental limits : a new conceptual framework to re-define marginal and extreme coral communities

2023

Article référencé dans le Web of Science WOS:000999781800001

Schoepf V., Baumann J. H., Barshis D. J., Browne N. K., Camp E. F., Comeau S., Cornwall C. E., Guzman H. M., Riegl B., Rodolfo-Metalpa Riccardo, Sommer B.

Science of the Total Environment, 2023, 884, p. 163688 [15 p.] ISSN 0048-9697

The worldwide decline of coral reefs has renewed interest in coral communities at the edge of environmental limits because they have the potential to serve as resilience hotspots and climate change refugia, and can provide insights into how coral reefs might function in future ocean conditions. These coral communities are often referred to as mar-ginal or extreme but few definitions exist and usage of these terms has therefore been inconsistent. This creates signif-icant challenges for categorising these often poorly studied communities and synthesising data across locations. Furthermore, this impedes our understanding of how coral communities can persist at the edge of their environmental limits and the lessons they provide for future coral reef survival. Here, we propose that marginal and extreme coral communities are related but distinct and provide a novel conceptual framework to redefine them. Specifically, we de-fine coral reef extremeness solely based on environmental conditions (i.e., large deviations from optimal conditions in terms of mean and/or variance) and marginality solely based on ecological criteria (i.e., altered community composi-tion and/or ecosystem functioning). This joint but independent assessment of environmental and ecological criteria is critical to avoid common pitfalls where coral communities existing outside the presumed optimal conditions for coral reef development are automatically considered inferior to coral reefs in more traditional settings. We further evaluate the differential potential of marginal and extreme coral communities to serve as natural laboratories, resilience hotspots and climate change refugia, and discuss strategies for their conservation and management as well as priorities for future research. Our new classification framework provides an important tool to improve our understanding of how corals can persist at the edge of their environmental limits and how we can leverage this knowledge to optimise strat-egies for coral reef conservation, restoration and management in a rapidly changing ocean.

Sciences du milieu [021] ; Ecologie, systèmes aquatiques [036]

Fonds IRD [F B010088073]

fdi:010088073