The research team combined databases of coral species traits with their ecological characteristics, including their resistance to thermal bleaching, to see how best to select sets of species for restoration using a hedging approach.
Newswise — A groundbreaking method for choosing coral species for reef restoration has been presented to resource managers and conservationists. Collaborating at a workshop hosted by the University of Melbourne (U Melbourne) and the Australian Institute of Marine Science (AIMS), an international team of scientists has developed this innovative approach. In an article recently published in the Journal of Applied Ecology, the team, led by a researcher from the University of Hawai‘i (UH) at Mānoa, unveiled a strategy for identifying a set of key coral species that will effectively uphold vital ecosystem functions necessary for reef health.
Coral reefs around the world are vanishing at an alarming rate due to various human-induced disturbances, with global warming posing the most significant threat. Consequently, coral reef restoration has become a burgeoning field of research and industry. While most coral reefs consist of tens to hundreds of stony coral species, available resources for restoration are insufficient to revive them all. Currently, there is a lack of methods for selecting species that can best preserve species diversity and ecosystem functioning.
"The services that coral reefs provide to humans, such as coastal protection and fisheries, rely on a wide array of coral species with diverse life history strategies, encompassing variations in growth rates, morphologies (ranging from mounding to branching shapes), and vertical distribution," explained Joshua Madin, the lead author of the study and a research professor at the Hawai‘i Institute of Marine Biology in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). "Therefore, when restoring coral reefs, practitioners must consider this diverse assemblage of local species, much like how forest restoration requires more than just fast-growing plants."
To address this challenge, the research team combined databases of coral species traits with their ecological characteristics, including their resistance to thermal bleaching, to determine the most suitable sets of species for restoration using a hedging approach, akin to portfolio investment strategies.
"Selecting species based on ecological characteristics is crucial for hedging against future species loss, while trait diversity is vital for mitigating the loss of specific ecosystem services, reef-building groups, life history categories, and evolutionary diversity," Madin emphasized.
This hedging approach offers a straightforward framework to assist restoration practitioners in choosing target coral species for their projects, taking into account the spatial scale and available resources.
"For instance, if a program has the capacity to focus on only 20 coral species, they would want to concentrate on sets of species that yield the greatest ecosystem benefits," explained Professor Madeleine van Oppen from U Melbourne and AIMS, the senior author of the paper. "Current coral restoration programs often prioritize easily collectible 'weedy' coral species, which share similar characteristics and are unable to support ecosystem services on their own."
The study also revealed that in cases where species data are limited, randomly selecting species is preferable to choosing those that are easy to collect. The additional effort required for collection proves worthwhile in terms of preserving vital ecosystem services that communities rely on. This method can be applied to any coral reef as long as coral trait data are available.
Given the escalating risks faced by coral reefs, including those in Hawai’i and Australia, where people rely on reefs for tourism, recreation, coastal protection, and sustenance, coral restoration has become a focal point of extensive research and development. The novel approach for selecting coral species is already being implemented in a hybrid reef program in Hawai’i, funded by the Defense Advanced Research Projects Agency. The groundbreaking objective of this project is to create an engineered structure that provides habitat for corals and other reef organisms while safeguarding coastlines against flooding, erosion, and storm damage.
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