The first global assessment of all non-extinct terrestrial vertebrate species has identified more than 500 “lost” species, ones that no one has seen in more than 50 years.
Arne Mooers, a professor of biodiversity at Simon Fraser University (USF, a Canadian public research institution) and co-author of the study, said there is a good chance that some of the species are not found because they live in inhospitable or difficult-to-access habitats, but others could be lost forever.
“In fact, we discovered that there were more than 500 animals living on land that had not been seen in more than 50 years. That’s almost double the number that have been declared extinct since the year 1500. There are a lot of them out there that we don’t know if they still exist.”
The scientists used a computer program that went through the group’s database to identify the missing species.
The researchers reviewed information on 32,802 animals on the International Union for Conservation of Nature’s Red List of Threatened Species and identified 562 missing. Their findings appear in the journal Animal Conservation.
That list defines extinction as “when there is no reasonable doubt that the last individual of a species has died,” which can be difficult to verify. According to Mooers, it classifies 75 of these 562 lost species as “possibly extinct.”
The researchers note that the existence of many species with an uncertain conservation status may become increasingly problematic as the extinction crisis worsens and more of them disappear.
Date of absence or last seen
The criteria used to list a lost species was the date of absence or last seen, or any account of the first time the animal was collected and named, he said. “There are a lot of these indications that it was, in fact, lost.”
One of the Canadian species in this situation is the Eskimo curlew, a shorebird that nested in the northernmost part of the tundra and migrated to Argentina, Mooers said.
A few Eskimo curlews were seen in Texas in 1962 and another was shot in Barbados in 1963, but that was the last confirmed sighting, he said.
“It’s our most famous and unique lost species, I think, and it’s probably extinct. It is one of the saddest, I think, ”he considered, referring to the Canadian bird.
A total of 311 species of terrestrial vertebrates have been declared extinct since the year 1500, which means that 80 percent more are considered lost than declared extinct.
Reptiles lead the way with 257 considered lost, followed by 137 amphibians, 130 mammals and 38 birds. Most of these animals were last seen in megadiverse countries such as Indonesia (69), Mexico (33), and Brazil (29).
Although not surprising, this concentration is important, according to the researchers. “The fact that most of these lost species are found in megadiverse tropical countries is concerning, given that they are expected to experience the greatest number of extinctions in the coming decades,” according to a statement from Tom Martin, lead author of the study and a member from the UK’s Paignton Zoo.
Mooers, who led the study, added: “While theoretical estimates of ongoing ‘extinction rates’ are good, it seems best to look closely at the actual species.”
Gareth Bennett, a USF undergraduate who did much of the data combining, added, “We hope this simple study will help bring these lost species to the forefront of future searches.”
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