Computer modelling aims to inform restoration, conservation of coral reefs
A research team from UBC Okanagan has created a computer modeling program to help scientists predict the effect of climate damage and eventual restoration plans on coral reefs around the world.
This is a critical goal, says Dr Bruno Carturan, because climate change is killing many coral species and could lead to the collapse of entire coral reef ecosystems. But because they are so complex, studying the impact of destruction and regeneration on coral reefs is logistically challenging.
Real-world experiments are impractical, as researchers must manipulate and disrupt large areas of reefs, along with coral colonies and herbivore populations, then monitor changes in structure and diversity over many years.
“Needless to say, conducting experiments that disrupt natural coral reefs is unethical and should be avoided, while using large aquariums is simply unfeasible,” said Dr. Carturan, who recently completed his doctoral studies at the Irving K. Barber Faculty of Science. “For these reasons, such experiments have never been conducted, which has hampered our ability to predict coral diversity and the associated reef resilience.”
For his latest research, recently published in Frontiers in Ecology and Evolution, used Dr. Carturan models to create 245 coral communities, each with a unique set of nine species and each covering an area of 25 square meters. The model represents coral colonies and different types of algae that grow, compete and reproduce together, while also being influenced by climate.
Crucially, all major components of the model, including species traits such as competitiveness and growth rates, are informed by pre-existing, real-world data from 800 species.
The research team simulated several scenarios — including strong waves, a cyclone or intense heat — then measured the resilience of each model reef, taking into account damage, recovery time and habitat quality 10 years after the disturbance.
By running so many computer modeling scenarios, the team found that more diverse communities — those with species with very different traits — were the most resilient. They were better at repairing damage and had better habitat quality 10 years after the disturbances.
“More diverse communities are more likely to have certain species that are very important for resilience,” explains Dr. Carturan out. “These species have certain characteristics: they are morphologically complex, competitive and have good resilience. When they were present in a community, these species maintained or improved the quality of the habitat after the disturbance. In contrast, communities without these species often ended up dominated by harmful algae.”
Coral diversity determines the strength and future health of coral reefs, he adds. Coral species are the foundation of coral reef ecosystems because their colonies provide the physical habitat where thousands of fish and crustaceans live. Among them are herbivores, such as parrotfish and surgeonfish, which maintain the coral habitat by eating the algae. Without herbivores, the algae would kill many coral colonies, collapsing the coral habitat and destroying its many populations.
“What is unique about our study is that our results apply to most coral communities in the world. By measuring the effect of diversity on resilience in more than 245 different coral communities, the diversity of diversity likely overlaps with the actual coral diversity that is found in most reefs.”
At the same time, the study provides a framework to successfully manage these ecosystems and aid in coral reef recovery by revealing how to manage the resilience of coral communities by establishing colonies of species with complementary traits.
Looking ahead, there are other questions that the model can help answer. For example, the coral species vital to resilience are also most affected by climate change and may not be able to recover if strong climatic heat waves become too frequent.
“It’s a very real and sad conclusion that one day we could lose these important species,” said Dr. Carturan. “Our model can be used to experiment and perhaps determine whether the loss of these species can be offset by other, more resistant species, which would prevent the eventual collapse of the reefs.”
Researcher uses computer modeling to predict reef health
Bruno S. Carturan et al, Functional Richness and Resilience in Coral Reef Communities, Frontiers in Ecology and Evolution (2022). DOI: 10.3389/fevo.2022.780406
Quote: Computer modeling aims to inform coral reef restoration and conservation (2022, Aug. 2), retrieved Aug. 3, 2022 from https://phys.org/news/2022-08-aims-coral-reefs.html
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