According to a new study, more than one-fifth of the world's reptile species are threatened with extinction, with those living in forests facing far greater threats than those living in arid areas. Researchers discovered that up to 21.1 percent of all known reptile species were threatened in the most comprehensive extinction-risk assessment ever conducted on reptiles.
"The number of threatened species is simply overwhelming," said study co-author Neil Cox. The findings were published in the journal Nature on April 27.
Research Findings:
There had been no formal attempt prior to this new research to determine how many reptiles were on the verge of extinction. Conservationists instead relied on the IUCN Red List of Threatened Species, which provides information on the risk status of birds, mammals, and amphibians.
Using the Red List criteria, the researchers discovered that 1,829 out of 10,196 reptile species were vulnerable, endangered, or critically endangered, accounting for 21.1 percent of all known species.
They also discovered that 57.9 percent of turtles and 50 percent of crocodiles are threatened; overall, the IUCN considers 40.7 percent of amphibians, 25.4 percent of mammals, and 13.6 percent of birds to be threatened, according to the Red List.
The global study lasted 15 years and involved 961 researchers from 24 countries spread across six continents.
Researchers examined existing surveys and datasets of turtles, crocodiles, lizards, snakes, and tuatara in Africa, the Americas, Asia, Australia, the Caribbean, Europe, and Oceania for the studyTuatara are endemic to New Zealand and are thought to be the last survivors of a reptile order that dates back to the Triassic period, according to the New Zealand Department of Conservation.
Agriculture, logging, urban development, and invasive species, according to the authors, are all threatening reptiles around the world. This would explain why the researchers discovered that 30% of reptiles living in forests were at risk of extinction compared to 14% of reptiles living in arid habitats, according to the authors.
The researchers also discovered that threatened reptiles were concentrated in Southeast Asia, West Africa, northern Madagascar, the Northern Andes, and the Caribbean, allowing conservationists to focus their efforts where they are most needed.
The researchers also narrowed down the primary threats to various groups of reptiles. For example, lizards that live on islands are threatened by predators introduced by humans. According to the IUCN, the main threats to turtles and crocodiles are hunting and poaching.
Because of a lack of long-term studies, the authors are unsure how climate change is threatening reptiles. However, they wrote in the paper that climate change is a "looming threat" because it narrows the window when cold-blooded animals can forage, and it can also change the sex ratios of offspring in species where that is determined by temperature.
"Reptiles are not often used to inspire conservation action, but they are fascinating creatures that play essential roles in ecosystems all over the world," said Sean T. O'Brien, President and CEO of NatureServe, which led the study in collaboration with the IUCN and Conservation International. We all benefit from their role in pest control and as prey for birds and other animals.
(Source: Live Science)
