A UBC Okanagan research team has created a computer modeling program to help scientists predict the impact 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 can lead to the collapse of entire coral reef ecosystems. But because they are so complex, it is logistically challenging to study the impact of coral reef destruction and regeneration.
Real-world experiments are impractical, as researchers would have to manipulate and disturb large areas of reefs, along with coral colonies and populations of herbivores, and then monitor changes in structure and diversity over many years.
“Needless to say, conducting experiments that will disturb natural coral reefs is unethical and should be avoided, and using large aquariums is simply impossible,” says Dr. Carturan, who recently completed his doctoral studies at the Irving K. Barber Faculty of Science. “For these reasons, no such experiments have ever been conducted, which has hindered our ability to predict coral diversity and the relative resilience of reefs.”
For his latest research, recently published in Frontiers in Ecology and EvolutionDr. Karturan used models to create 245 coral communities, each with a unique assemblage of nine species and each occupying an area of 25 square meters. The model represents colonies of corals and different species of algae growing, competing and reproducing together, while also being affected by climate.
Crucially, he notes, all key components of the model, including species characteristics such as competitive abilities and growth rates, are informed by pre-existing real-world data from 800 species.
The research team simulated various scenarios—including strong waves, a cyclone, or extreme heat—and then measured the resilience of each reef model by considering damage, recovery time, and habitat quality 10 years after the disturbance.
By running so many scenarios with computer modeling, the team found that the most diverse communities—those with species with very dissimilar traits—were the most resilient. They were better at recovering from damage and had better habitat quality 10 years after disturbance.
“More diverse communities are more likely to have certain species that are very important for resilience,” explains Dr Karturan. “These species have special characteristics – they are morphologically complex, competitive and with good recovery capacity. When present in a community, these species maintained or even increased habitat quality after disturbance. In contrast, communities without these species were often dominated by harmful algae at the end.’
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 form the natural environment where thousands of fish and crustaceans live. Among them are herbivores, such as parrotfish and surgeonfish, which maintain coral habitat by eating the algae. Without herbivores, the algae would kill many coral colonies, causing the coral habitat to collapse, 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 range of diversity likely overlaps the true diversity of corals that found on most reefs.”
At the same time, the study provides a framework for successfully managing these ecosystems and helping to restore coral reefs by revealing how resilience of coral communities can be managed by colonizing species with complementary traits.
Looking ahead, there are other questions the model can answer. For example, coral species that are critical for resilience are most affected by climate change and may not be able to recover if extreme heat waves become too frequent.
“It is a very real and sad conclusion that one day we may lose these important species,” says Dr Karturan. “Our model could be used to experiment and perhaps determine whether the loss of these species can be compensated by some other, more resilient ones that will prevent the eventual collapse of the reefs.”
Researcher uses computer modeling to predict reef health More information: 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 Provided by University of British Columbia
Reference: Computer modeling aims to inform restoration, coral reef conservation (2022, August 2) retrieved August 2, 2022 by
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