Take a good look at the oceans today—there’s a strong chance they won’t look the same in a few decades, scientists say.
As water temperatures rise around the world, some marine animals are already migrating to other areas in response. Habitats are shifting and evolving. Some species are disappearing, and others are moving in to take their place.
The ecological consequences of all these changes—and how they may alter food webs and habitats and entire communities of organisms—remain to be seen. In the meantime, scientists have identified another concern. These kinds of shifts may make it harder to protect marine animals in the future.
Today, marine protected areas are among the primary tools for conserving marine habitats and protecting threatened species. These are areas where fishing and other disturbances are supposed to be limited. They’re kind of like the ocean equivalents of national parks.
Traditionally, these protected areas are bound by geography. They cover a certain area of the ocean, and they don’t move. But now, some experts argue that shifting ocean conditions driven by climate change call for a more dynamic approach to marine conservation.
In an editorial published yesterday in the journal Science, one group of experts makes the case for a new approach: movable marine sanctuaries whose boundaries would shift across the ocean as needed.
“Things are changing at such a rapid rate, and in some cases animals are moving north, in some cases habitats are really shifting and literally moving in space,” said ocean scientist Sara Maxwell of the University of Washington, one of the editorial’s authors. “In other words, a static boundary isn’t going to protect an area that might exist now—50 years from now it might be totally different.”
As a result, she said, “Having some mechanism to put into place protections that can follow those shifts is huge.”
It’s a good time to be having these discussions, Maxwell and her co-authors note. Members of the United Nations are currently renegotiating the terms of a 1982 agreement known as the Law of the Sea Convention, which regulates international use of the oceans and their resources. The agreement hasn’t been updated since it was first developed, according to Maxwell.
“One of the main goals is to include in the Law of the Sea specific protections for biodiversity on the high seas,” she said. “That did not previously exist.”
The editorial suggests these ongoing negotiations are an opportunity to include new kinds of conservation techniques that would better reflect changes to the ocean over the last few decades—particularly the growing influence of climate change.
A more dynamic approach
There’s some debate among scientists about the role of marine protected areas in a warming world. Some research, such as an August 2019 study in Biological Conservation, has suggested that marine sanctuaries don’t necessarily increase every ecosystem’s resilience to climate change. Even if fishing and other human activities are limited, some spaces are still equally vulnerable to the effects of warming.
In this sense, there’s no substitute for addressing the impacts of climate change by reducing global greenhouse gas emissions.
That said, pollution, overfishing and other human pressures are major threats to many marine ecosystems in and of themselves. Marine protected areas, when properly enforced, can cut down on these pressures.
One concern about climate change is that it will cause vulnerable species to migrate out of the sanctuaries that were set up to protect them, putting them at risk of human exploitation.
Movable marine protected areas aren’t a new idea. They’re already used in certain local conservation efforts.
In the United States, for instance, NOAA’s TurtleWatch map displays up-to-date information about the sea surface temperatures preferred by loggerhead sea turtles. The map helps fishing vessels avoid areas where turtles are likely to be hanging out at any given time, reducing turtle bycatch in the process.
The authors of the editorial envision this kind of approach being expanded to international waters around the globe. If policymakers want to protect a certain species or habitat that’s prone to moving around, they could use advanced modeling techniques to forecast where the animals are likely to be found.
In previous decades, this kind of approach may have been too complex. But the authors argue that scientists now have the technology to predict where vulnerable species are likely to be moving and to communicate this information to ships on the high seas in real time.
The idea isn’t to replace stationary marine protected areas, Maxwell said. Rather, mobile areas would complement existing sanctuaries—and maybe increase the effectiveness of stationary ones. They could create movable, protected corridors that allow vulnerable species to migrate safely from one static marine sanctuary to another.
Establishing these kinds of safe networks may be one of the most valuable ways to protect migrating species, said Tammy Davies, a marine science officer at the conservation group BirdLife International. That includes animals that aren’t necessarily being driven to new locations by global warming but are naturally moving around the ocean throughout the year.
“You’d be able to increase the MPA network as it is—particularly for migratory species, which are pretty much poorly represented in MPAs as it is now,” Maxwell said.
Still, there would be challenges, experts say.
Even stationary marine protected areas are often difficult to enforce, says marine ecologist John Bruno of the University of North Carolina at Chapel Hill. Figuring out how to monitor and prevent violations in international waters is probably the biggest challenge for marine protected areas on the high seas, whether they’re mobile or not.
And climate change could introduce some added complexities.
Protecting a single, mobile species is one thing. But if conservationists want to protect a specific type of habitat or community of organisms, it could get tricky. As marine animals migrate and disperse in response to climate change, not every species may move in the same direction or at the same speed.
In other words, an ecosystem or habitat that exists as a complete unit today may not exist at all, anywhere, a few decades down the road. This is one of the biggest uncertainties associated with climate change, Bruno noted—and it poses a major challenge for conservationists trying to decide what kinds of environments they want to focus on protecting.
Still, Bruno supports more dynamic conservation tools. There are issues to address in terms of implementation—but new strategies are necessary in a rapidly changing world.
“These are the kind of bold ideas people are starting to talk about,” he said.
Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.