Nearly one fifth of the world's reptile species are estimated to be threatened with extinction, according to a paper published by the Zoological Society of London (ZSL) on 15 February. The paper outlined the findings of a study carried out in conjunction with experts from the Species Survival Commission of the International Union for the Conservation of Nature (IUCN) and printed in the journal Biological Conservation.
The study is the first of its kind summarising the global conservation status of reptiles. More than 200 world-renowned experts assessed the extinction risk of 1,500 randomly selected reptile species from across the globe.
Out of the estimated 19% of species threatened with extinction, 12% were classified as critically endangered, 41% as endangered and 47% as vulnerable.
Three critically-endangered species were also highlighted as possibly extinct. One of these, a jungle runner lizard ameiva vittata, has only ever been recorded in one part of Bolivia. With the lizard's habitat virtually destroyed, two recent searches for the species have been unsuccessful.
Levels of threat remain particularly high in tropical regions, mainly as a result of habitat conversion for agriculture and logging.
Lead author of the paper, Dr Monika Böhm, said: "Reptiles are often associated with extreme habitats and tough environmental conditions, so it is easy to assume that they will be fine in our changing world. However, many species are very highly specialised in terms of habitat use and the climatic conditions they require for day-to-day functioning. This makes them particularly sensitive to environmental changes."
Extinction risk is not evenly spread throughout the highly diverse group: freshwater turtles, for example, are at particularly high risk, mirroring greater levels of threat in freshwater biodiversity around the world. Overall, the study estimated 30% of freshwater reptile species to be close to extinction, which rises to 50% when considering freshwater turtles alone, as they are also affected by national and international trade.
Although the threat remains lower in terrestrial reptiles, their often restricted ranges, specific biological and environmental requirements and low mobility make them particularly susceptible to human pressures. In Haiti, six of the nine species of anolis lizard included in the study have an elevated risk of extinction, due to extensive deforestation affecting the country.
Head of ZSL's Indicators and Assessment Unit, Dr Ben Collen, said: "Gaps in knowledge and shortcomings in effective conservation actions need to be addressed to ensure that reptiles continue to thrive around the world. These findings provide a shortcut to allow important conservation decisions to be made as soon as possible and firmly place reptiles on the conservation map."
Philip Bowles, co-ordinator of the Snake and Lizard Red List Authority of the IUCN Species Survival Commission commented: "This is a very important step towards assessing the conservation status of reptiles globally. The findings sound alarm bells about the state of these species and the growing threats that they face globally. Tackling the identified threats, which include habitat loss and harvesting, are key conservation priorities in order to reverse the declines in these reptiles."