‘Often ignored’ species face twice the threat of extinction, study warns

Plants and animals that don’t have enough data to be properly assessed appear to have twice the risk of extinction than those that have been assessed, meaning more species could face the planet’s extinction than previously thought, a study has warned.

The researchers analyzed the risk of extinction of species assessed on the Red List of Threatened Species and found that 56% of species in the data deficient (DD) category were threatened, compared to 28% of those assessed.

A species is considered DD if there is not enough data on its distribution or population, and these species are “generally ignored” in studies looking at biodiversity impacts, the researchers wrote in the paper, published in Communications Biology. The red list, created by the International Union for Conservation of Nature (IUCN), is used by governments to define which species should be prioritized for conservation actions.

The IUCN assesses over 140,000 species based on criteria such as population size, trends and threats. There are 20,000 DD species on the red list and policymakers generally regard them as least concern, but this study showed that a much higher proportion of these species are threatened. The researchers said that 85% of DD amphibians were at risk, as were more than half of mammals, reptiles and insects.

The species may be DD because they are very few, sightings are rare, or they may be enigmatic species, making it difficult to estimate their population. To overcome these problems, the researchers created an algorithm that predicted the probabilities of species at risk of extinction based on key factors they knew, such as the global distribution of those species, weather conditions, changes in land use, pesticide use, and intruder threats. species. The researchers ran the algorithm on DD species if their geographic distribution was known, which it was for about 38% of them.

Some DD species with very high probabilities of being at risk include the Sierra Miahuatlan spike frog, which has a 95% chance of being endangered, as well as the Sholai night frog and a Mexican fish called Ajijic silverside.

Previous studies have looked at the risk of extinction of DD species, but this one is the most comprehensive, looking at 21 taxonomic groups — still “a tiny fraction of what exists in the world,” according to lead researcher Jan Borgelt of Norwegian University. of Science and Technology (NTNU).

Borgelt said: “Overall, what is most impressive is that in almost all terrestrial and coastal areas of the world, the average risk of extinction would be higher if we take data-deficient species into account.” If DD species were included, 33% of the species on the red list would be threatened, versus 28%, the algorithm predicted.

Central Africa, South Asia and Madagascar are the regions with the highest number of DD species at risk, although the researchers have not analyzed why this might be the case. Up to half of DD marine species living in coastal areas are at risk of extinction.

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Professor Jane Hill of the University of York, who is also a trustee of the British Ecological Society and was not involved in the research, said: “The study is important because the approach they use [machine learning methods] could be applied to many other species.”

About 18,000 invertebrates have been assessed for extinction on the red list, but 27% are DD. The rate of insect extinction is eight times faster than that of birds, mammals and reptiles, according to analyzes published last year, with known declines likely to be the “tip of the iceberg”. Research has shown that vertebrates receive nearly 500 times more funding for each species than invertebrates, which are perceived as less “charismatic”.

Hill said: “It has long been recognized that the IUCN red listing approach is focused on only a small proportion of all species on Earth and that it needs to be more representative. So while this study provides more information about the DD species, we still know very little about most species on Earth.”

Some of the DD species under threat

• An example where the algorithm can be used is with the newly recognized rice whale, which scientists thought could be a species for nearly a decade, although it took years to get official recognition. Now only about 50 of them remain, in the area affected by the Deepwater Horizon oil spill, where there is heavy boat traffic and oil and gas extraction. There are no local protests because no one knows it exists, says marine researcher Dr. Chris Parsons of the University of Exeter, who believes that the DD category should be given “assume threatened” status. He said: “If immediate precautionary measures had been taken years ago when they suspected a new species, it could have forced research to be conducted immediately and triggered emergency measures that could have prevented it from becoming critically endangered.”

• From 23 beaked whale red list species, seven are DD. They spend a lot of time underwater (their dives can last three hours) and are difficult to see in the wild, but they are at risk from a number of threats, including man-made noise pollution in the ocean, which could be causing mass strandings. . . The data on beaked whales is so poor that the algorithm was unable to assess their risk.

Indo-Pacific Humpback Dolphins in Southeast Asia they were considered DD for a long time, so there was no funding and little interest in studying them. They are now considered “near threatened” and have become Hong Kong’s official mascot, as well as being listed under the US Endangered Species Act, which is aiding international conservation efforts.

Find more coverage of the age of extinction here and follow the biodiversity reporters Phoebe Weston and Patrick Greenfield on Twitter for all the latest news and features

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