The survival of dozens of Australian reptile species, including turtles, crocodiles and lizards are threatened with extinction, a global team of scientists have revealed.

A 20-year study, involving hundreds of researchers, including a team from the University of Western Australia, have found that 1 in 5 reptiles in Australia could become extinct in the near future without enhanced conservation efforts.

UWA biologist Nicki Mitchell said the $5m project identified 40 new endangered reptile species that are not currently listed as threatened in Australia – meaning they are not specially protected – and 1,829 species worldwide.

“The major reasons for their endangerment are their habitats being destroyed, ongoing poaching, and climate change,” Prof Mitchell said.

“A lot of species have no protection because they haven’t formally been listed under Australia’s environmental laws, but once they are, it prevents developers from clearing habitat.

“Every country’s scientists will be making sure that this work is under their government’s noses.”

The team studied 10,196 reptile species and looked at their distribution while also identifying risk factors, such as climate change.

They found that freshwater turtles are most affected by droughts, floods, pollutants and new diseases and that reptiles tend to live in the same areas as other at-risk species, such as birds.

The study also found 58 per cent of turtles and half of all crocodiles are at risk of extinction.

Turtles and reptiles are popular amongst poachers and are often sold illegally on the black market.

Department of Biodiversity, Conservation and Attractions  Parks and Wildlife Service research scientist David Pearson said this study highlights the urgency of intervention.

“This is a 20-year study that was taken across the globe by well-trained researchers, so it’s hard to ignore the truth of the extinction of historically significant reptiles,” Dr Pearson said.

“We are working closely with Nicki to get these species on the International Union for Conservation of Nature’s threatened species Red List, as well as the Australian threatened species list administered by the Environment Protection and Biodiversity Act.

“My own background in threatened reptiles and python ecology makes me yearn for these reptiles, and my position to help is made clear.”

Data collected was analysed to look at the patterns of extinction risk in reptiles relative to amphibians, birds and mammals.

The study, which was published last month in the science journal Nature, also found that due to climate change, sex ratios are expected to change with species that have their sex determined by nest temperature.