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This article comes from the official account of Wechat: ID:fanpu2019, author: Andy Carstens

If you misjudge, it will hurt the life you are trying to protect.

Write article | Andy Carstens

Translation | Wang Chao

On a cloudy morning in 2021, Mark A. Michaels, a self-taught ornithologist, was marking a maple tree in the forest of Louisiana. At this time, he saw a bird flying under the canopy 50 yards away. Based on its size and neck length, Michaels inferred that it was a duck. However, he found that the bird would intermittently fold its wings-"ivory beak" during flight! Michaels was surprised that ducks could not fly like this. He was sure that the bird was the ivory-billed woodpecker (ivory-billed woodpecker, scientific name Campephilus principalis) he had been looking for for 15 years. Since 1944, there has been no definite evidence of field identification of this bird.

Photo 1: Arthur A. Allen and the Macaulay library at the Cornell lab of ornithology, an ivory-billed woodpecker taken in 1932, as an assistant researcher of the American Bird Society, Michaels had suspected many times that he had seen an ivory-billed woodpecker, several times in that tree, but he could never convince himself that it was true. This time it was different. "that was the first time I was absolutely sure that I really saw it."

Are there any ivory-billed woodpeckers in the wild? Michaels is convinced, but it is hard for others to say. In September 2021, the U.S. Fish and Wildlife Service (US Fish and Wildlife Service, or USFWS) issued a ruling declaring that ivory-billed woodpeckers-- and 22 other species-- were extinct. If the ruling takes effect, the ivory-billed woodpecker will be removed from the federal list of endangered species and the conservation measures required by the Endangered species Act will be officially lifted, for example, without having to protect the bird's habitat or trying to increase its population size.

However, the data behind the proposal is controversial. At a hearing in January 2022, USFWS received conflicting evidence that scientists were deeply divided about the status of the woodpecker and deserved further review. As a result, USFWS issued a reprieve on July 6: another six months before deciding whether to remove the ivory-billed woodpecker from the list of endangered species.

Researchers face many difficulties in determining whether a species is really extinct, such as the ivory-billed woodpecker. "it's very difficult to prove that something doesn't exist." So says H.Resit Akcakaya, an ecologist at Stony Creek University. And "do not see", can not prove that it is extinct. The International Union for Conservation of Nature (International Union for Conservation of Nature, or IUCN) is an organization that tracks species conservation based on surveys, modeling and expert advice. According to IUCN guidelines, "this category (taxon) is considered Extinct when there is no reasonable reason to suspect that the last individual is dead." But usually, researchers do not know when the last individual died, or even whether the last individual has died.

More importantly, according to Akcakaya, misjudging the extinction of a species comes at a price. If a species has become extinct but has been regarded as an endangered species, it will make people underestimate the proportion of extinction and lose sight of the higher picture of nature conservation. At the same time, the money that could have been used to protect vulnerable species is used to find species that do not exist. Conversely, if a species is declared extinct if it is not extinct, these struggling species may suffer further damage.

The price of prematurely declared extinction is the Cebu flower pecker (Cebu flowerpecker, scientific name Dicaeum quadricolor) is a small songbird native to the island of Cebu in the Philippines, colorful and beautiful. It is presumed to have been extinct before 1906-ornithologists in the early and mid-20th century failed to find any trace of it, while a 1998 paper published by conservation biologist Nigel Collar and the International Bird Life Association (BirdLife International) speculated that deforestation caused Cebu flower-peckers to lack habitat to survive. This conclusion did not inspire people to protect Cebu Island. On the contrary, logging continues to destroy the few forests left. Until the 1990s, when Cebu flower-peckers were rediscovered, there were only sporadic forests on the island, covering less than 3/10000 of the original area. Although Cebu flower-peckers still exist today, their future is not optimistic: according to the species assessment released in 2021 on the IUCN Red list of Endangered species, the number of Cebu flower-peckers is about 60 to 70, and the number is decreasing.

Mistakenly declaring a species extinct is sometimes like casting a spell that makes the species really extinct. As Akcakaya said, "what worries us most is that we think a species is extinct, so we no longer protect it, and then it really becomes extinct due to lack of protection." This situation is called "Romeo error" (Romeo Error). Because in the final ending of Romeo and Juliet, Romeo thought Juliet was dead, so he committed suicide, and then Juliet committed suicide. "this is a self-fulfilling prophecy."

Would USFWS have made a Romeo mistake if he decided to declare the ivory-billed woodpecker extinct? "it's possible," Michaels said, but he was optimistic that this would not happen, mainly because the agency had thought the bird was extinct for decades, but its operation didn't seem to have had a bad effect. USFWS has a species recovery plan for each endangered animal. According to the ivory-billed woodpecker recovery plan, conservation efforts focus on finding the bird and protecting its habitat only after the population is found. Although there is no formal requirement to protect the forest habitat of ivory-billed woodpeckers, existing good management practices have already done so, Michaels said. Michaels hopes that even if the ivory-billed woodpecker is declared extinct, it will continue to be managed in this way. But he also knows that once extinction is declared, there will be less incentive to maintain existing management practices, which may hurt species that live in the same habitat as the bird.

If a species has been declared extinct and is rediscovered, it may cause more problems. Ak ç akaya says the discovery of the "Lazarus species" may reduce public trust in scientists and, in some cases, stimulate poaching markets. Michaels said that while the spooky ivory-billed woodpecker doesn't have to worry about poachers at 01:30, demand for collections could soar as soon as the bird is found.

In addition, Michaels pointed out that if too many kind-hearted people want to help find ivory-billed woodpeckers, it may damage their habitat instead. In the past, people tried to prove that the woodpecker did not become extinct, only to cause their casualties: in the 1930s, hunting and logging led to a sharp decline in the number of ivory-billed woodpeckers. people began to wonder if the woodpecker had been killed and extinct. To allay public suspicion, Louisiana Congressman Mason Spencer shot and killed an ivory-billed woodpecker and used its body as evidence. For all these reasons, Michaels said, they will not now reveal the exact location of the search for ivory-billed woodpeckers.

The so-called Lazarus species are creatures thought to be extinct but later found in the wild to keep a secret from getting involved in the extinction spiral. Ecologists who encounter Lazarus species are often faced with dilemmas. On the one hand, sharing the news of "rediscovery" can arouse public support for protecting the creature, but on the other hand, it may also incite poachers. Vincent Nijman, a wildlife trade expert at Oxford Brooks University in the UK, said animals could end up in an extinction vortex: every time an animal is killed, the value of the remaining animals increases. Growing demand may drive poachers to wipe out a species for profit. This is how the native Java rhinoceros (Rhinoceros sondaicus) became extinct in Vietnam in 2010 (Biol Conserv,174:21-29Rol 2014).

A few years later, Sumatran rhinoceros (Dicerorhinus sumatrensis) suffered the same misfortune. The Sumatran rhinoceros disappeared for some time in history and was rediscovered in Kalimantan, Borneo in 2013. Throughout history, until the early 20th century, the number of this rhinoceros in Southeast Asia has been considerable. In the 1970s, in order to get precious rhino horns, various poaching activities made them nearly extinct (Biol Conserv,175:21-24Rol 2014). At that time, although many people thought the rhino was extinct, poachers didn't think so, Nijman said. They believe that the rhinoceros can still be found in some remote areas, but it is too difficult to invest in months of exploration. It wasn't until 2013, when Sumatran rhinoceros reappeared and made global headlines, that things changed. "Rhino hunters in Sumatra left for Kalimantan as soon as they heard the news."

In Nijman's view, it might have been wiser to keep the new discovery secret. In this way, people can devote more resources to animal protection and help species recover. But after the news was announced, a lot of money had to be invested overnight to protect Sumatran rhinos from poachers, and the rainforest could not be enclosed and managed, so it was no easy task to deal with poachers. Even delaying such announcements for a few years could buy some critical recovery time for Lazarus species, Nijman said.

Photo 2: since the horns of white rhinos are embedded in their faces, poachers will kill them, then remove the entire skull and trade it on the black market. Modern methods: estimating the probability of extinction of species Akcakaya is now volunteering to chair IUCN's Standards and petitions Committee. To assist scientists in determining whether a species is extinct, IUCN has developed a method that allows scientists to make better use of existing data, he said. The methodology, released in 2017 and incorporated into the IUCN guidelines in 2019, combines two ways to assess the likelihood of extinction to infer the state of a species (Biol Conserv, 214, 336-42). The first approach is the "exhaustive Survey" (exhaustive surveys), which surveys all known or possible habitats that a species has existed in history during the seasons and periods in which they are supposed to appear. The more the number of surveys, the wider the search area, the higher the credibility of the assessment. The second way is to estimate the probability of extinction based on the scope and severity of the threat. For example, the more habitat of a missing species is reduced, the more likely it is that the species has become extinct.

Although government agencies such as USFWS follow specific laws and regulations to make their own decisions, this approach can provide some guidance on whether to continue to invest in protecting a species.

Stuart Butchart, an ornithologist with the International Bird Life Association, was one of the first scientists to test the method. In his view, this approach is valuable, "forcing users to clearly consider information from different sources" and "helping to improve the consistency of assessments." In 2018, Butchart and his collaborators used this method to evaluate dozens of bird species (Biol Conserv, 227: 9-18). When the probability of extinction assessed by both approaches is more than 50%, they recommend that the species be considered "critically endangered" and "potentially extinct". It is only when both assessments have a higher than 90% probability of extinction that it is recommended that species be classified as "extinct".

For ivory-billed woodpeckers, Butchart used a second approach-based on threats to animals-to estimate the probability of extinction at 75 per cent, mainly due to habitat loss, while investigations and recorded sightings showed a low probability of extinction, only about 20 per cent. The latter method (that is, the investigation method) will take into account that there may be misrecognition in the records, but if multiple records have the same misunderstanding, then the probability of extinction may be underestimated.

Based on these results, Butchart and his colleagues suggest classifying ivory-billed woodpeckers as critically endangered (critically endangered) species. Of course, the current assessment may change if you take into account the latest evidence gathered by Michaels and others recently.

Final decision: whether a species still exists, while data-driven methods are helpful, they are sometimes not enough to reach a final conclusion. Kelsey Neam, an environmentalist from the nonprofit Re:wild, says that in some cases, people simply don't have enough information about a species to make reliable predictions. She has tested IUCN's method with amphibians, but has not yet used it to infer the state of a species, in part because of a lack of information. "it would be nice if we had a lot of amphibian data, but we don't."

No matter how much data is available or how little is available, the final conclusion will depend on the decision of the expert group. As the assessment coordinator of the IUCN amphibian expert group, Neam leads a working group of experts from specific areas to review the status of species, like the work of a jury. "sometimes people agree and everyone will say, 'Yes, this is completely extinct'. But at other times, there will be a lot of debate." Local experts who love a species sometimes hesitate to declare it gone forever, Neam said. The reason for their hesitation may be the fear of making Romeo mistakes, the taxonomic importance of the species, or simply because it "looks cool". As an expert in using IUCN standards, Neam's job is to be neutral and impartial. "I often feel like I'm a lead juror and it's stressful," she said.

She also mentioned that one of the most important factors in the review process was to determine whether the investigation was detailed, but she acknowledged that "this is a qualitative job." Sitting with investigators for discussion helps to assess the scope of the investigation. When people hesitate, or mention that a species might be found in another area, "then the alarm goes off in my head," she said. "you know, it's not wise to declare a species extinct at that moment." In general, the result of a discussion in such a situation is to decide first where to conduct the next search.

When everyone agrees that a species no longer exists, the air suddenly quiets down, Neam said. "you get goose bumps. Because it's not like you can easily move on to the next one after you've sentenced one. At that moment, we sat there and observed a moment of silence for the disappearance of those species."

Michaels hopes the ivory-billed woodpecker won't go that far. But he is worried about another thing: the demand for the quality of the evidence is so high that he may not be able to provide clear pictures to prove that the bird is still alive. He told USFWS that many of the bird photos taken in the 1930s put an unrealistic burden of proof on everyone, because most of them were taken from the height of the bird's nest, close to the bird and "posing." by contrast, his evidence is blurred images and video clips extracted and enhanced from drone shots.

"it's a very, very difficult thing," Michaels said, "because you have to shoot at the sky, it's all backlit, and the birds fly very fast." In the frame-by-frame demonstration, he pointed out the remarkable features of the ivory-billed woodpecker, such as white secondary wing feathers, a long neck, and stripes on the bird's back from shoulder to face. "if only there was a picture that could clearly show its big white beak," but none of it was in his picture.

Photo 3: the photo was taken in 2021, with a silhouette of a bird in the middle. The photo was cited in a preprint paper co-authored by Michaels as evidence that ivory-billed woodpeckers still exist. For now, he can only wait for the USFWS to make a ruling. "I don't know what the result will be, and I won't guess." Michaels said the agency's previous extension order was a placebo, indicating that the government is seriously considering the possibility that ivory-billed woodpeckers still exist. But there was not a trace of doubt in his own mind: "I'm 100% sure it's there."

Photo 4: Mark Michaels (left) and Steve Latta of the American Bird Society look at woodpecker foraging traces left on trees. This article is authorized to be translated from

Https://www.the-scientist.com/careers/how-do-scientists-decide-a-species-has-gone-extinct-70972

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