A new model that could help restore coral reefs

A research team from UBC Okanagan has developed a computer modeling program to help scientists predict the impact of climate damage and potential restoration strategies on coral reefs around the world.

A UBCO researcher has created a modeling program that can help scientists plan for the restoration and conservation of coral reefs affected by climate change. Image credit: Jean-Philippe Maréchal.

According to Dr Bruno Carturan, this is a crucial goal because climate change is causing the extinction of many coral species and could trigger the collapse of entire coral ecosystems. However, due to their complexity, it is logistically difficult to study the effects of coral reef destruction and regeneration.

Real-world studies are impractical because they require manipulating large reefs, coral colonies, and herbivore populations, as well as monitoring long-term changes in structure and diversity.

Needless to say, conducting experiments that will disturb natural coral reefs is unethical and should be avoided, while the use of large aquariums is simply impractical. For these reasons, no such experiment has ever been conducted, which has hampered our ability to predict coral diversity and associated reef resilience..

Dr. Bruno Carturan, University of British Columbia

Dr. Carturan recently completed his doctoral studies at the Irving K. Barber School of Science.

Dr Carturan used models to generate 245 coral communities for his most recent study, which was published in Frontiers in Ecology and Evolution. Each of these communities contained a distinct collection of nine species and covered an area of ​​25 square meters. Colonies of corals and various types of algae that grow, compete and reproduce alongside each other while being influenced by climate are depicted in the model.

It is important to note that all essential elements of the model, including species characteristics such as competitive propensities and growth rates, are based on pre-existing real data from 800 species.

The research team replicated many events, such as powerful waves, a cyclone or extreme heat, then assessed the resilience of each model reef by noting the extent of damage, how quickly it recovered and the state of the ecosystem ten years after the disturbance.

Scientists found that the most diverse communities – those whose species had noticeably disparate traits – were the most resilient after testing a large number of scenarios using computer modelling. Ten years after the disturbances, they were better able to repair the damage and had better habitat quality.

More diverse communities are more likely to have certain species that are very important for resilience. These species have particular traits: they are morphologically complex, competitive and with a good capacity for recovery. When present in a community, these species maintain or even increase the quality of the habitat after the disturbance. In contrast, communities without these species were often dominated by nuisance algae in late.

Dr. Bruno Carturan, University of British Columbia

The long-term strength and health of coral reefs is determined by coral diversity, he continues. As their colonies create the physical habitat where countless fish and crustaceans thrive, coral species are the foundation of coral reef ecosystems.

Among them are herbivores like parrotfish and surgeonfish which consume algae to preserve the coral ecosystem. Without herbivores, algae would decimate many coral colonies, causing coral habitat to collapse and wiping out its many populations.

What is unique about our study is that our results apply to most coral communities around the world. By measuring the effect of diversity on resilience in over 245 different coral communities, the extent of diversity likely overlaps with the actual coral diversity found in most reefs..

Dr. Bruno Carturan, University of British Columbia

The research also demonstrates how the resilience of coral communities could be managed by establishing colonies of species with complementary characteristics, which will contribute to the restoration of coral reefs and provide a framework for successfully managing these ecosystems.

There are other problems that the model can solve in the future. For example, the most vulnerable coral species, which are crucial for resilience, are also the most affected by climate change and may not be able to recover if extreme heat waves occur too frequently.

Dr Carturan says: “It is a very real and sad conclusion that we could one day lose these important species. Our model could be used to experiment and perhaps determine if the loss of these species can be compensated by other, more resistant ones, which would prevent the eventual collapse of the reefs..”

Journal reference:

Carturan, BS, et al. (2022) Functional richness and resilience in coral reef communities. Frontiers in Ecology and Evolution. doi.org/10.3389/fevo.2022.780406.

Source: https://www.ubc.ca/

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