Can Coral Gardening Save the World’s Reefs?

This was written for my environmental reporting class in late February. I’m currently looking for a place to publish it.

In the past four decades, 40 percent of the world’s coral reefs have been lost, largely due to global climate change and other manmade issues. This epidemic has scientists scrambling for ways to halt or reverse reef degradation and save these vital ecosystems. Over the last two decades, a deceptively simple and promising method to save reefs has emerged: plant new ones.

Baruch Rinkevich, a senior scientist at the Israel Oceanographic and Limnological Research Institute, has been studying coral reef gardening – growing small coral-nubbins cut from larger corals in nurseries and replanting them in damaged reefs – since the mid ‘90s. Rinkevich explained his methods in the upcoming volume of Current Opinion in Environmental Sustainability. After decades of smaller studies, he said he wanted to summarize his conclusions in an article geared toward the scientific community in general, not just those who closely follow reef restoration.

There are a handful of people gardening coral worldwide, and Rinkevich is one of the most well known scientists promoting the method. He said people need to accept that the environment is changing and that his field needs to work on rebuilding those reefs that can survive in this new reality. Although some other reef experts question the viability of gardening as a restoration method, Rinkevich is not dissuaded.

He was inspired by the success of silviculture – controlling the growth of forests to meet specific industrial or environmental needs. “The tree species are different, in many places the technologies are different, but the rationale and the approaches are the same,” he said.

The coral-nubbins are grown in floating mid-water nurseries close to the shore. Rinkevich’s initial attempts to grow them on the ocean floor were unsuccessful as they were too vulnerable to weather disturbances and predation from starfish and certain fish. Nurseries suspended in the water turned out to be safer and more flexible; they also exposed the coral to more nutrients from passing currents. More than 100,000 colonies from 86 different coral species have been successfully farmed worldwide, according to Rinkevich’s study, a total that includes those grown by him and a handful of other scientists.

Ken Nedimyer has cultivated endangered corals as president of the non-profit Coral Restoration Foundation in the Florida Keys. In 2001, Nedimyer started a nursery for staghorn coral, which have seen their populations decrease by 98 percent in the last 30 years.

Now, there are about 40,000 staghorn and elkhorn coral in the Coral Restoration Foundation’s nurseries. Last year the group planted 10,000 coral after they spent eight months in the nurseries. Nidemyer said they plan to plant double the amount this year. The program’s success builds upon itself, he explained. “In two years you’re going to look around and say, ‘Wow, there’s a lot of coral out there,’” he said.

Rinkevich argues that restoration methods need to be more forward thinking, and the scientific community needs to accept that the reefs of tomorrow are not going to look like the reefs of yesterday. Gardening allows scientists to focus on corals that are better suited to future environmental conditions like warming waters and ocean acidification. “This is ecological engineering. You plan ahead of time, you put all the consideration into the cultivation, so you end up with a completely different type of [reef],” he said. For instance, Rinkevich found that Pocillopora damicornis, or cauliflower coral, is hardy and grows fast. Nidemyer said his team focuses on strains of coral that have advantageous genetic adaptations.

“You’re going to find some corals that are going to do well on the reefs and the reefs are going to be dominated by those corals,” Nidemyer explained.

But Tim McClanahan, senior zoologist at the Wildlife Conservation Society, has doubts about just how helpful gardening going to be. McClanahan, who has worked with Rinkevich before, said that gardening is “a boutique solution.” In his opinion, it’s helpful for small-scale priority sites, but it can’t operate at a large enough scale to address the problems facing reefs worldwide.

There’s also cost to consider. Transplanting coral on a large enough scale to make an impact is an expensive endeavor. The Coral Restoration Foundation is a nonprofit, and Rinkevich depends on research grants. The comparison to silviculture can only go so far, as McClanahan noted that people earn money directly from the replanted forests. “The relationship between coral and fisheries is much less direct, and so the economic incentives to do it are not there [in] the same way,” he said.

McClanahan also notes that gardening fails to address the underlying problems that are causing the degradation in the first place. “We’ve got to deal with other issues like carbon emissions and overfishing on very large scales,” he said. “Those are sort of bigger problems in my opinion.”

Bill Precht was the program manager for the Florida Keys Marine Sanctuary back when Nedimyer first began replanting coral, and he disagrees with McClanahan’s take. He recalled being skeptical himself, but after seeing the success of Nedimyer’s work he became much more optimistic. “Even if mortality is very high, at the number they’re planting them and the growth rate that they have, there’s a possibility to restore an entire reef,” he said.

Rinkevich said the next step is to restore a reef on a much grander scale, planting more than a million coral. He doesn’t have many details as of now, because he’s currently in the early stages of looking for a location and sponsors.

“Kudos to him for doing what he does,” McClanahan said, despite his skepticism. “I mean, we need to put more effort into coral reefs. They’re not doing well and they need people like him and me out there looking at [all] the options.”

“I really think we can buy some time and hopefully the world will wake up and realize they’re on a collision course with disaster and change things,” Nedimyer said. “And if we’ve done some of the work that we’re trying to do now, we’ll have something to look at in 50 years. And we’ll say, ‘Wow, we’re glad we did.’”