Interview with Nancy Knowlton about marine biodiversity and climate change

There is a nice interview with Nancy Knowlton in Yale Environment 360, excerpted below:

e360: Much of your earlier research was done in the Caribbean, in Jamaica. What was the state of the coral reefs in that part of the world at the time? And what kind of changes physically have you seen in recent decades?

Knowlton: You know, I always start my talks by showing a picture that I took as a grad student in 1975. And at that time there was living coral everywhere. The bottom was about 70 percent living coral. And we knew the reefs weren’t in pristine condition because there were essentially no big fish. In fact there weren’t that many fish at all because Jamaica is a really poor country and subsistence fishing had basically stripped the reef of most of the fishes because people were desperate to just feed their families… It’s very hard to say, ‘Don’t fish for five years and then they’ll come back.’ So we knew the fish communities weren’t in great shape, but the corals were spectacular. And I have to say there were a lot of distinguished coral reef biologists working in Jamaica at the time… None of us really predicted what would happen.

First in Jamaica we had this huge hurricane [Hurricane Allen in 1980], which broke corals up into little bits and killed a lot of them. And then there was this big disease — not of corals, but of the black spine sea urchin. Because there were no fish around it was the most important seaweed-eater on the reef. And this disease wiped out almost all of the sea urchins throughout its range and, as a result, the seaweeds went absolutely crazy. And throughout the Caribbean most of the reefs flipped from coral-dominated state to a seaweed-dominated state. So within about ten years of my starting to work in Jamaica the reefs effectively vanished.

e360: What are some of the other more vulnerable regions in the world as far as the state of reefs?

Knowlton: Well, anywhere near people is potentially vulnerable, unless people really get together and figure out what they’re going do to make sure they don’t lose their reefs. The Australians are the gold standard for reef protection, the Great Barrier Reef Marine Park Authority. A third of it is off limits to fishing and that is incredibly important in terms of giving reefs resilience, which is the ability to bounce back if something bad happens.

e360: What part can and should marine protected areas play?

Knowlton: Well, in the developed countries, marine protected areas — in the tradition of take a part of the habitat and put it off limits to fishing — is a critical component of reef management. Because fishing pressure can be so intense elsewhere that you need those pockets of protection where big fish are allowed to grow up and make lots of babies.

But a lot of reefs are in places in the coral triangle in New Guinea, Indonesia, the Philippines, where it’s very difficult, for socioeconomic reasons, to just put reefs off limits. But there you can take advantage of more traditional management schemes that people have used for decades or centuries. It’s more about managing fishing than putting fishing off limits.

e360: Does it make sense to target certain areas where the stressors are less and the coral systems are still relatively biodiverse?

Knowlton: Well, I think that’s in fact what people have done. For example the big marine protected areas that were set aside in the Pacific under the Bush Administration, those were very important because so many of them are so remote they are in pretty good shape. They still have pretty intact fish communities and very healthy coral communities. That is an important part of the approach that you need to take. Now, those areas are not protected from warming waters or ocean acidification. But what you see when you look at those places is that they do have a lot of resiliency. They have bleaching, but they are able to bounce back. So that kind of protection does play an important role.

Ultimately, if we don’t do something about carbon dioxide concentrations in the atmosphere, local management will not succeed. But effective local management actually buys incredibly important time while we figure out how we’re going to deal with the carbon dioxide problem.


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