More than a fifth of reptiles are threatened with extinction

Over half of turtles and crocodiles could be driven to the edge in the coming decades, as human hunting drives them towards extinction. 

The first comprehensive conservation assessment of reptiles found that 21.1% of the animals were classed as Vulnerable, Endangered or Critically Endangered. This is significantly more than birds, of which 13.6% are threatened, but less than the 40.7% of amphibians at risk of extinction.

The scientists warn that the equivalent of 15.6 billion years of evolutionary history, longer than the age of the universe itself, will be lost if these species are wiped out.

Co-author Mike Hoffmann, the Head of Wildlife Recovery at the Zoological Society of London, says that this will lead to the extinction of unique species with ways of living unlike any other in the world.

'From turtles that breathe through their genitals to chameleons the size of a chickpea, reptiles are an eclectic bunch,' says Mike. 'Many reptiles, like the tuatara or pig-nosed turtle, are like living fossils, whose loss would spell the end of not just species that play unique ecosystem roles, but also many billions of years of evolutionary history. 

'Their future survival depends on us putting nature at the heart of all we do.'

The researchers have warned that the outcome of international negotiations on biodiversity set to be held in China later this year will be 'especially critical' to saving these threatened species.

The report has been published in Nature. 

What extinction threats do reptiles face?

Reptiles first appeared more than 300 million years ago, and have since diversified into species which can fly, swim, burrow and climb. Around 10,000 species of reptile have been described, living on every continent on Earth except Antarctica.

The animals face challenges across all of their habitats, primarily due to the influence of humans. The study found that the greatest threat facing reptiles was agriculture, which threatened more than half of all lizards and snakes.

For turtles and crocodiles, direct persecution such as hunting is the most prominent threat. The trade in turtle shells and crocodile skins, as well as the consumption of their flesh, is driving down populations across the world.

Other forms of land use change and habitat destruction, such as urban development, logging and pollution, were also among the severe threats facing the group. As a result, reptiles living in forests were among the most threatened, with 30% of species at risk of extinction. 

In future, the threat of climate change is likely to grow as its impact become more severe. Co-author Prof Stephen Blair Hedges said this would put pressure on species living in isolated habitats such as islands as their ability to disperse is limited.

'These are generally fragile ecosystems, and so any long-term changes and extreme events can add to existing natural and anthropogenic extinction pressures,' says Stephen. 'Sea level rise can affect island species as only small rises will cause many islands around the world to disappear beneath the waves.'

While the study concludes that around a fifth of the reptiles are threatened with extinction, the conservation status for 15% of species are unknown. If all of these data deficient species are also threatened, then as many as 33% of the animals could be at risk.

Co-author Dr Bruce Young says this highlights another major threat facing reptiles - apathy.

'Reptiles, to many people, are not charismatic and so there has previously been more focus on furry and feathery vertebrates for conservation,' he says. 'It has taken over 15 years to assemble this report, and it took a long time to obtain funding.'

Without reptiles, there would be severe impacts around the world, including a loss of prey for larger animals, insect populations growing out of control and the permanent altering of valuable ecosystems. 

How can we prevent reptiles from going extinct?

While the study warns that many reptiles face an uncertain future, it offers hope that the conservation efforts aimed at other groups of animals can also benefit reptiles.

'There had been concern that reptiles were falling through the hole in our conservation safety net,' Bruce says. 'However, we found that if you protect the places where birds, mammals, amphibians and reptiles live together, you protect more reptiles than you would expect by chance. 

'This is good news because the extensive efforts to protect better known animals have also likely contributed to protecting many reptiles. Habitat protection is essential to buffer reptiles, as well as other vertebrates, from threats such as agricultural activities and urban development.'

The publication of this conservation assessment will also help inform decision making on where the best interventions can be made to protect reptiles. The researchers also hope that it will feed into the upcoming COP15 biodiversity summit, which is set to be held in Kunming, China, in October.

'Kunming is where the world will come together to agree how to protect biodiversity into the future,' Bruce explains. 'The last globally agreed biodiversity targets expired in 2020, so we're in need of a new framework as the biodiversity crisis has only grown more severe since then. 

'It's critical there is agreement on truly effective measures to be taken by the world's governments, and means to measure their effectiveness, if we are to be able to turn around this crisis.'