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Climate-driven disturbances such as marine heatwaves are rapidly reducing coral cover and degrading reef ecosystems worldwide. Using a mathematical model, a research team led by Subhendu Chakraborty at the Leibniz Centre for Tropical Marine Research (ZMT) has identified a key mechanism that helps explain why, after a disturbance, some corals recover faster than others and contributes to single out traits relevant for bolstering restoration strategies. The new study, published in the Journal of the Royal Society Interface, focuses on coral recruitment – the process through which coral larvae settle and grow into adulthood.
Earlier research had shown that recruitment can depend on how many adult corals are already present in the reef. Building on this knowledge, the new study demonstrates that the way recruitment depends on the density of adult corals strongly influences how fast reefs recover after disturbances such as bleaching.
+++ Multiple stresses on reefs: from heatwaves to crown-of-thorns starfish +++
Coral reefs are among the most productive and diverse ecosystems on our planet. Yet, they are increasingly threatened as corals decline through a variety of disturbances such as marine heatwaves (and subsequent bleaching), nutrient eutrophication, and outbreaks of coral-eating crown-of-thorns starfish. According to the Coral Reef Monitoring Network (GCRMN), 84% of the world’s reefs have already experienced bleaching-level heat stress. Last year’s Global Tipping Points Report warned that the world had reached its first climate tipping point as warm-water coral reefs were dying worldwide.
Despite widespread damage, some reefs show signs of recovery while others continue to decline. Understanding why this happens is essential for developing effective conservation strategies. A team of researchers from ZMT and Vrije Universiteit Amsterdam set out to examine whether differences in coral recruitment patterns shape a reef’s ability to recover after disturbance.
“Previous research has shown that baby corals of different species settle and grow in different ways depending on how many adult corals are already present on the reef,” says marine scientist Subhendu Chakraborty, first author of the study. “In other words, some species produce new young corals more easily when only a few adults are present nearby, while others depend on having many adults on the spot.”
Based on these findings, the scientists developed a mathematical model of coral-macroalgae competition to test three coral recruitment scenarios: recruitment that steadily increases with the number of adult corals present nearby; recruitment that is particularly effective when only a few adults remain in the vicinity; or recruitment that only increases when many adult corals are present.
The researchers then simulated severe coral loss and examined which types of corals were able to recover and outcompete macroalgae under different environmental conditions. The model used empirical data from a reef-building Acropora coral species.
“Not all corals have the same ability to bounce back,” explains Chakraborty. “Some coral species, such as Acropora, can recover and outcompete macroalgae even when only a few adults survive; other species struggle to recover unless many adults remain in the vicinity of settlement or when the disturbance is very mild,” he says.
“Overall, we could show that small differences in how corals recruit can determine whether a reef survives after a disturbance or eventually succumbs to a regime shift whereby macroalgae takes over”, adds Agostino Merico, marine scientist at ZMT and senior author of the study.
+++ Understanding coral traits to improve reef recovery +++
ZMT reef ecologist and co-author Sonia Bejarano summarizes the findings and their implications for reef restoration. “Coral recovery depends not just on how strong a disturbance is, but also on the biological traits of the coral species”, she says. “Choosing the right coral species could boost reef restoration efforts.”
Co-author Bob Kooi, a mathematical modeller from the Vrije Universiteit Amsterdam, adds: “If coral cover drops too low, reefs may not recover on their own. Understanding the biological differences between corals helps to explain why some reefs recover and others collapse after severe disturbances like bleaching.”
Healthy coral reefs support food security, jobs, and coastal safety for hundreds of millions of people in tropical and subtropical areas. Their decline affects both nature and human communities. Hence, the study does not only shed light on reef dynamics, it has also relevant implications for reef conservation efforts through developing science-based solutions for sustainable management.
The team is now designing real-life experiments to test the model results under a broader set of conditions. “We want to connect mathematical modelling efforts with laboratory experiments to further improve predictions in more complex environmental scenarios,” conclude Chakraborty and Merico.
Dr. Subhendu Chakraborty | WG Systems Ecology | Leibniz Centre for Tropical Marine Research (ZMT)
Email: subhendu.chakraborty@leibniz-zmt.de
Prof. Dr. Agostino Merico | WG Systems Ecology | Leibniz Centre for Tropical Marine Research (ZMT)
Email: agostino.merico@leibniz-zmt.de
Chakraborty S, Bejarano S, Kooi B, Merico A. 2026 Impacts of different recruitment density-dependences on post-disturbance coral reef recovery. J. R. Soc. Interface 23: 20250281. https://doi.org/10.1098/rsif.2025.0281
Coral-dominated reef in Raja Ampat (Indonesia) including reef-building corals of the genus Acropora
Copyright: Sonia Bejarano, Leibniz Centre for Tropical Marine Research (ZMT)
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Coral-dominated reef in Raja Ampat (Indonesia) including reef-building corals of the genus Acropora
Copyright: Sonia Bejarano, Leibniz Centre for Tropical Marine Research (ZMT)
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