Amidst all the bad news about coral reef bleaching, an international team has shed light on what conservation measures are working to preserve these fragile ecosystems while balancing various social and ecological needs.
“People have different goals for sustaining coral reefs,” says lead author Joshua Cinner from James Cook University in Queensland, Australia. “Some want to promote the conservation of fish stocks, some want to preserve biodiversity, and some want to maintain key ecological functions.
“Managing even one of those goals is extremely difficult, but we wanted to find out whether some reefs can have it all.”
They found that, indeed, a small proportion of reefs nailed all three criteria, publishing their findings in the journal Science.
“These are like the Hollywood A-listers of coral reefs,” Cinner says.
Coral reefs are one of the world’s richest biodiversity hotspots, providing habitats for a quarter of marine species. They provide environmental protection and food for millions of people and their dollar value is estimated in the trillions.
To investigate how to best protect them while meeting human needs, the team assessed nearly 1800 reef sites across the tropics from 41 regions across the globe and set a high, medium and low target for each goal.
To meet the fisheries goal, they assessed the number of fish. Ecological health was determined by the algae scraping potential of the parrotfish, considered crucial for reef survival, and biodiversity by the assortment of different species.
Sites that robustly met each goal, by 75%, made the A-list while those that met middle (50%) or least stringent (25%) targets were B- and C-listers.
They found that only 5% of openly fished reefs met the A-list criteria, but were geographically spread out, appearing in a third of the countries studied across the Caribbean, Indian and Pacific Oceans.
Around 12% of reefs met medium targets across all three goals and a third met the least stringent targets – more than half of reefs didn’t even make the C-list.
Next, they used models to identify how local management efforts, such as marine reserves, could help reefs make the A-list, considering drivers of resource exploitation, environmental conditions and human pressures such as population size, trade and migration.
This revealed that it’s all about the location – marine reserves with restricted fishing do best in areas with low human pressures. In areas of high human pressure, coral reef degradation is too severe for local management to make a difference.
Therefore, saving coral reefs relies on international action to address climate change. But effective management is also needed to sustain them, and this is where the study can point the way.
“We show where managers will be able to maximise their ability to simultaneously meet multiple goals, such as fisheries, biodiversity and ecosystem function, and likewise, where they will be wasting their time,” Cinner says.
“It appears that remote reserves are critical to supporting multiple goals.”
Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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