This week, scientists unveiled a new standard for assessing the status of plant and animal species. Instead of focusing on decline, this new approach aims to measure recovery.

The Swiss-based International Union for Conservation of Nature (IUCN) developed and adopted the new standard, which it has called the “green status of species.”

“Conservation has been dominated by a lot of doom and gloom,” said Molly Grace, a conservation biologist at the University of Oxford and the co-chair of the IUCN task force that worked on the green status. “[It] is a useful metric to see what conservation has done and what conservation can do.”

The green status score ranges from 0 to 100, with scores calculated in relation to the population and range of the species before human impact. Zero indicates that a species is extinct in the wild, and 100 indicates that it is “fully recovered,” with a number of intermediate categories. The standard also evaluates the impact of past conservation efforts; what would happen if conservation efforts stopped; as well as future potential for conversation gains and species recovery.

While the standard is being announced now, the actual assessments will happen over the coming years on a species-by-species basis. As they are completed they will appear alongside IUCN’s related conservation metric: the red list of threatened species, which has assessed 134,425 species, a number that green-status advocates hope it could eventually keep pace with as well.

A study in the journal Conservation Biology, released at the same time as this week’s announcement, found that the red list was a “significant predictor” of the green-status score — meaning species at higher risk of extinction are generally further from recovery, and vise versa. But there are many exceptions. Liz Bennett, who helped design the standard and is the vice president for species conservation at the Wildlife Conservation Society, said “the new standard tells a much more complete story.”


The study conducted a number of preliminary test assessments for the green status, including the East Asian mangrove. The tree is listed as a species of “least concern” on the red list, but was actually highly depleted due to timber harvesting in the 1950s. It has since started to recover — in part due to climate change expanding its range — and its green status would be “moderately depleted.”

The California Condor has been on the red list as “critically endangered” since 1994. Grace, who co-authored the study with more than 200 other scientists, said it actually gets high marks in the “conservation legacy” portion of the green-status assessment. What that captures, she said, is that “without past conservation, the Condor would almost certainly be extinct today.”

For 39 of the 181 tested species, the study estimated that halting conservation actions could result in extinction within three generations.

Conversely, Bennett points to the gray whale, which is a species of “least concern” on the red list because its populations remain numerically high in certain areas. But, what that does not show, she said, is that the whale is no longer present in large swaths of its pre-human range. That gives it a green-status score of “largely depleted.”

“It’s those exceptions that are important,” said Stuart Pimm, an ecologist and conservation expert at Duke University. “This paper points out a useful distinction between the possibility for recovery and the risk of going extinct.”

Others find positives in the green status as well. “I think this is a more optimistic view that hopefully focuses on encouraging action,” said Leah Gerber, director of the Center for Biodiversity Outcomes at Arizona State University.


Bennett says that because the green status is more sensitive to change than the red list, it could also be useful to donors or other financial supporters of conservation work who want to measure progress. Funders, she said, are beginning to ask, “Can you actually change the green status of this species?”

It could also alter the underlying incentive for funding, said Jacob Malcom, who leads the Center for Conservation Innovation at Defenders of Wildlife. Money, he explained, may diminish as a species moves up the red list and could dry up before it is fully recovered. Tying support to the green status could change that.

Malcom would like to see government agencies, such as the U.S. Fish and Wildlife Service, integrate or even adopt the green-status framework. The agencies’ current species status assessments are complex, Malcom says, and make it difficult to pull out high-level conclusions across species.

“We need a nice systematic way to boil that information down into a small number of variables that are useful to decision-makers,” he said.

In an email, the Fish and Wildlife Service declined to comment on the green status “at this early stage.”

But the new standard is not without its faults. Malcolm notes that it does not look at exactly what conservation methods worked as part of recovery. And Gerber added that the cost of conservation is also not factored into the calculations. “If it’s not feasible,” she said, “that’s irrelevant.”


Pimm is a fan of the red list but worries the more cumbersome green status will not prove practical.

“They are a long way from people adopting these things,” he said, explaining that scientists working intimately with species probably already know much of the information that would be in green-status assessment. “I’m not sure how useful it would be for those of us that are trying to prevent species going extinct in the wild.”

Grace acknowledges shortcomings and says some of them will be addressed as next steps. But she looks forward to when the first batch of assessments get uploaded to the IUCN website later this fall.

“Conversation is working,” she said. “The green status gives us a way to see that in a standardized way.”