More than 40 percent of amphibian species, more than a third of marine mammals and almost a third of sharks and fish are endangered.
An analysis of the risks facing some 8,000 known amphibian species by the UN and published in an IPBES report found that up to 50 percent could be endangered, dramatically higher than earlier estimates.
The surge is due to the inclusion of approximately 2,200 species that were previously underrepresented due to lack of data; now, based on new models, the researchers say at least 1,000 more species are threatened with extinction.
The researchers used a method called feature-based spatial-phylogenetic statistical framework to estimate the extinction risks of species for which data is lacking.
This combined data on their ecology, geography and evolutionary characteristics with the respective extinction risks of each factor to make a prediction.
The team notes that only about 44 percent of amphibians currently have up-to-date risk assessments.
“We have found that over 1,000 data-deficient amphibians are endangered and almost 500 are endangered or critically endangered, mostly in South America and Southeast Asia,” said Pamela González del Pliego of University of Sheffield and Yale University.
“Urgent conservation measures are needed to prevent the extinction of these species.”
The species most at risk are likely also those we know least about, the researchers say, making it even more difficult to protect them.
A study published earlier this year found that 90 amphibian species have been wiped out due to a deadly fungal disease.
It infects frogs, toads and salamanders and has caused a sharp decline in the populations of over 400 species over the past 50 years.
The disease is called chytridiomycosis, which eats away at the skin of amphibians and threatens the extinction of more animals.
Native to Asia, it is present in more than 60 countries around the world, with the most affected parts of the world being tropical Australia, Central America, and South America.