The researchers looked at the extinction risk 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 insufficient data on its distribution or population, and these species are “generally ignored” in studies analyzing impacts on biodiversity, 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 determine which species should be prioritized for conservation action. The IUCN assesses more than 140,000 species based on criteria such as population size, trends and threats. There are 20,000 DD species on the red list and policy makers often consider them to be of least concern, but this study showed that a much larger proportion of these species are threatened. The researchers said 85% of DD amphibians are at risk, as well as more than half of mammals, reptiles and insects. Species may be DD because there are very few of them, sightings are rare, or they may be cryptic species, making it difficult to estimate their population. To overcome these problems, the researchers created an algorithm that predicted the likelihood of species becoming extinct based on key factors they knew, such as the global distribution of these species, climate conditions, changes in land use, pesticide use, and threats from invaders species. The researchers ran the algorithm on DD species if their geographic distribution was known, which was for about 38% of them. Some DD species with a very high chance of being endangered included the Sierra Miahuatlan spikethumb frog, which has a 95% chance of extinction, as does the Sholai night frog, and a Mexican fish called the Ajijic silverside. A female furcifer timoni, a species of chameleon found in Madagascar. The region is one of the three with the highest number of data-deficient species at risk. Photo: Jorn Kohler/WWF/PA Previous studies have looked at the extinction risk of DD species, but this is the most extensive, looking at 21 taxonomic groups – still “a small fraction of what’s out there in the world”, according to lead researcher Jan Borgelt of Norwegian University. of Science and Technology (NTNU). Borgelt said: “Overall, what is most striking is that in almost all terrestrial and coastal regions of the world, the average risk of extinction would be higher if data-deficient species were taken into account.” If DD species were included, 33% of red-listed species would be threatened, as opposed to the 28% predicted by the algorithm. Central Africa, South Asia and Madagascar are the regions with the highest number of DD species at risk, although the researchers did not examine why this might be. Up to half of marine DD species living in coastal areas are threatened with extinction. Professor Jane Hill from 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] it could be applied to many more genres.” About 18,000 invertebrates are assessed for extinction on the Red List, but 27% are DD. The rate of extinction of insects is eight times faster than that of birds, mammals and reptiles, according to an analysis 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 considered less “charismatic”. Hill said: “It has long been recognized that the IUCN Red List approach focuses on only a small percentage of all species on Earth and that it needs to be more representative. So although this study provides more information about DD species, we still know very little about most species on Earth.”
Some of the DD species are threatened
An example where the algorithm could be used is the recently recognized Rice’s whale, which scientists thought might be a species for nearly a decade, although it took years to be officially recognized. Now there are only about 50 of them left, in the area affected by the Deepwater Horizon oil spill, where there is a lot of boat traffic and oil and gas extraction. There is no local outcry because no one knows it exists, says marine researcher Dr Chris Parsons of the University of Exeter, who believes the DD class should be given ‘presumed threatened’ status. He said: “Had immediate precautionary measures been taken years ago when a new species was first suspected, it could have prompted an immediate investigation and emergency measures to be put in place which could have prevented it from becoming critically endangered.”
A beaked whale off the west coast of Mexico. Data on beaked whales is so poor that it has not been possible to assess how endangered they really are. Photo: Simon Ager/Sea Shepherd/Reuters Of the 23 beaked whale species on the red list, 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 human-made noise pollution in the ocean, which could cause mass strandings. Data on beaked whales is so poor that the algorithm could not assess how endangered they are. Indo-Pacific dolphins in southeast Asia 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 the official mascot of Hong Kong, as well as being listed on the US Endangered Species Act, which aids international conservation efforts. Find more coverage of Age of Extinction here and follow biodiversity reporters Phoebe Weston and Patrick Greenfield on Twitter for all the latest news and features
