A novel approach to choosing coral species for reef restoration has been presented to resource managers and conservationists. During a workshop organized by the University of Melbourne (U Melbourne) and the Australian Institute of Marine Science (AIMS), an international group of investigators collaborated to develop this approach.
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. Image Credit: Madin, et al. (2023).
This international team of scientists, guided by a University of Hawai’i (UH) at Mānoa scientist, disclosed a strategy for selecting a set of key coral species that would best maintain ecosystem functions critical to reef health in a study published today in the Journal of Applied Ecology.
Coral reefs are disappearing fast around the world as a result of a variety of anthropogenic disturbances, with global warming being the most serious threat. Coral reef restoration is a growing research field and industry in response.
Most coral reefs are made up of tens to hundreds of different stony coral species, but resources for coral reef restoration are inadequate to restore them all—currently, no methods for selecting species that will best preserve species diversity and ecosystem function.
The ecosystem services that coral reefs provide for people, such as coastal protection and fisheries, depend upon coral species with a broad range of what are called life history strategies, for example slow to fast growing, mounding to branching shapes, and under to upper story. Therefore, restoration practitioners need to consider this range of local species when restoring coral reefs—much like forest restoration requires more than just fast-growing plants.
Joshua Madin, Study Lead Author and Research Professor, Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai’i at Mānoa
The study team merged databases of coral species traits with ecological characteristics, such as thermal bleaching resistance, to determine how to best select sets of species for restoration using a hedging approach similar to that used for investment portfolios.
Selection based on ecological characteristics is important for hedging against future species loss, whereas trait diversity is important for hedging against the loss of certain ecosystem services, reef-building groups, life history categories, and evolutionary variety.
Joshua Madin, Study Lead Author and Research Professor, Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai’i at Mānoa
This hedging strategy provides a straightforward framework for restoration practitioners to use when selecting target species for their projects based on spatial scale and resources.
“For example, if a program only has funds to focus on 20 coral species, they would want to focus on the sets of species to get the most ecosystem bang for their buck. Current coral restoration programs tend to focus on easy to collect, “weedy" coral species, which have similar characteristics and cannot support ecosystem services on their own,” says Profesor Madeleine van Oppen, from U Melbourne and AIMS, who is the senior author on the paper.
The research also revealed that when species data is limited, choosing species at random is far superior to choosing species that are easy to collect. The additional effort required will pay off in terms of preserving ecosystem services on which communities rely. The method is applicable to any coral reef for which data on coral traits are available.
Coral restoration is a major focus of research and development as coral reefs face greater threats, particularly in Hawaii and Australia, where people rely on reefs for tourism, recreation, coastal protection, and sustenance.
The new method of coral species selection is already being used in a hybrid reef program in Hawai’i funded by the Defense Advanced Research Projects Agency. The groundbreaking project’s goal is to build an engineered structure that will provide a habitat for corals and other reef life while safeguarding coastlines from flooding, erosion, and storm damage.
Journal Reference:
Madin, J. S., et al. (2023). Selecting coral species for reef restoration. Journal of Applied Ecology. doi.org/10.1111/1365-2664.14447.