A Changing Climate for Endangered Species
|According to McClure, there are three basic ways that a species can survive climate change. It can move, it can adapt, or it can hunker down—that is, hang out in whatever remnants of its former range are still suitable.|
Elkhorn coral. Credit: NOAA
Staghorn coral. Credit: NOAA
Scientists are working to ensure that the Endangered Species Act remains effective in the face of a changing climate. A special section in the latest issue of Conservation Biology highlights their progress.
Forty years ago this month the Endangered Species Act became law, and since then it has proved an effective tool for protecting species near the brink of extinction and the habitats they depend on. But the world is a very different place than it was in 1973, and federal agencies are adapting their science and management to protect endangered species against the array of threats they face today.
When the Act was written, no one was thinking about climate change. Scientists operated under the assumption that the environment varied but was not changing in any particular direction, and that the past was a good guide to the future. That is no longer the case.
How should we incorporate climate change into our decision-making under the Endangered Species Act? A special section in this month's issue of Conservation Biology addresses this question with eight papers authored by NOAA scientists and their research partners who work on marine and aquatic species.
The language of the Endangered Species Act requires us to peer into “the foreseeable future” using the “best available science.” But future conditions are not guaranteed, and a changing climate can upset established trends. Making decisions under these conditions, and keeping up with emerging science, is a fundamental challenge when protecting endangered species.
The eight research papers aim to help with that. "We identify lessons learned and try to provide some tools for when scientists decide if a species is at serious risk, develop recovery plans, and identify critical habitat,” said Michelle McClure, the NOAA Fisheries biologist who led the team of scientists contributing to this special section of the journal.
Scientists have incorporated climate change modeling into several recent decisions on threatened and endangered species. Among them is the bearded seal, an Arctic species recently listed as threatened whose sea ice habitat is expected to shrink in coming decades. Another example is the 68 species of coral that are
collectively under review for listing under the Act. Their future is threatened by, among other things, warming-induced bleaching and ocean acidification.
“Climate change is just one more impact that you have to evaluate on top of all the other impacts that we have on endangered species,” McClure said, “But it's bigger, it's less fixable, and it's more pervasive, so we have to be creative in our approach.”
Chinook salmon are listed as threatened or endangered in many parts of their range. McClure worked with NOAA Fisheries scientist Krista Bartz and Annika Walters of the U.S. Geological Survey to analyze the impact of streamwater diversion on juvenile Chinook in the Pacific Northwest. Young salmon making their way to sea need healthy freshwater habitat, and dams, diversions, and other stream modifications affect their rate of survival. Climate change can magnify the impact of these human activities by changing the amount of rainfall and the frequency and intensity of storms.
The authors projected these combined human and climate impacts on Chinook salmon to the year 2040 using two different climate models, which they downscaled to the Pacific Northwest. Which climate models to use, how to downscale them, and how far into the future to look are the types of questions that this series of papers seeks to clarify.
“That’s where the rubber hits the road,” said Roger Griffis, the climate change coordinator for NOAA Fisheries. “We’re already doing these things. The question is— how can we do them more effectively and efficiently using the best available science?”
How do we help listed species survive in a changing climate? Scientists are evaluating several strategies. For instance, in the past, we identified critical habitats based on the current and historical range of a species. But as marine species shift their distributions in search of cooler water and food resources that are also shifting, identifying areas that are not used today but might be critical refuges in the future is vital.
Another strategy is to sustain genetic diversity as part of a species recovery plan. That diversity is the evolutionary raw material that allows a species to adapt to changing conditions, and by maintaining it we can help a species to survive.
According to McClure, there are three basic ways that a species can survive climate change. It can move, it can adapt, or it can hunker down—that is, hang out in whatever remnants of its former range are still suitable.
“We have to adapt our conservation plans to the mechanisms that individual species are using to survive in a changing environment,” McClure said.
Forty years after the passage of the Endangered Species Act, these papers show how scientists are working to ensure that the law remains effective in our fast-changing world. The statute is flexible enough to incorporate our new understanding of environmental change because it rests on these fundamental principles: use the best available science and look into the foreseeable future.
"The fundamental principles of the law are sound," said Roger Griffis. "The challenge is in how we apply those principles in a changing world." The research highlighted in this special section of Conservation Biology will help to show the way.