作者群表示，雖然全球爬蟲類評估（Global Reptile Assessment）終究將解決這個偏差，針對特定的爬蟲類的評估目前仰賴區域性的工作坊及IUCN SSC專家小組團隊。
They may not be cute and cuddly like pandas, nor charismatic like tigers, but many reptiles, too, are at risk of being wiped out by human activities, finds the first global analysis of extinction risk in reptiles, published Friday.
The scientists who assessed the conservation status of 1,500 randomly selected reptiles estimate that 19 percent of the world's 9,084 known species of reptiles are threatened with extinction.
Levels of threat remain particularly high in tropical regions as reptile habitat is converted to agriculture and logging.
The paper by the Zoological Society of London with experts from the International Union for the Conservation of Nature Species Survival Commission is published in the journal of "Biological Conservation." Some 200 scientific experts from around the world contributed to the study.
"This is a very important step towards assessing the conservation status of reptiles globally," says Philip Bowles, coordinator of the Snake and Lizard Red List Authority of the IUCN Species Survival Commission.
"The findings sound alarm bells about the state of these species and the growing threats that they face," said Bowles. "Tackling the identified threats, which include habitat loss and over-harvesting, are key conservation priorities in order to reverse the declines in these reptiles."
The class of reptiles takes in turtles and tortoises, lizards and snakes and Amphisbaenia, a legless group of animals closely related to lizards and snakes.
It also includes crocodiles, although they are genetically closer to birds than to other reptiles. In fact, the largest reptile on Earth is the sea-faring saltwater crocodile, which lives in northern Australia, Southeast Asia and on some Pacific islands.
A unique reptile is the Tuatara, an animal endemic to New Zealand which, though it resembles most lizards, is actually part of a distinct lineage, order Rhynchocephalia.
Out of the 19 percent of reptiles threatened with extinction, 12 percent are classified as Critically Endangered, 41 percent are considered Endangered and 47 percent are Vulnerable.
Freshwater turtles are at particularly high risk, mirroring greater levels of threat in freshwater biodiversity around the world.
Overall, the study estimated 30 percent of freshwater reptiles to be close to extinction, a percentage which rises to 50 percent when considering freshwater turtles alone, as they are also affected by national and international trade.
Three Critically Endangered reptile species may already have gone extinct, the scientists believe.
One of these, a jungle runner lizard, Ameiva vittata, has only been recorded in one part of Bolivia. With the lizard's habitat virtually destroyed, two recent searches for the species have been unsuccessful.
"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," says Dr. Monika Böhm, lead author on the paper. "However, many species are very highly specialized in terms of habitat use and the climatic conditions they require for day to day functioning. This makes them particularly sensitive to environmental changes."
While this is a globally representative study, the authors say more research is needed to close wide gaps in information about these species.
As a group, reptiles are poorly represented on the IUCN Red List of Threatened Species, with only 35 percent of described species evaluated, and those that are evaluated were done so in a nonsystematic manner, the IUCN said in 2011.
Although the Global Reptile Assessment will in the long run address this bias, the authors say, the current assessment process relies on regional workshops and the formation of IUCN SSC Specialist Groups for specific reptiles.
The Global Reptile Assessment has carried out comprehensive assessments for North America, Madagascar and New Caledonia, with complete endemic-only assessments having been carried out in the Philippines, Europe and selected island groups – the Seychelles, Comoros and Socotra. There are still large geographical gaps which are only slowly being addressed, namely in Africa, Latin America, Asia and Australia.
The authors write, "Our results emphasize the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information."
Both reptiles and amphibians have been "greatly overlooked in reserve selection strategies," the authors warn, urging that these species be considered when protected areas are set aside.
"Gaps in knowledge and shortcomings in effective conservation actions need to be addressed to ensure that reptiles continue to thrive around the world," says Dr. Ben Collen, who heads the Zoological Society of London's Indicators and Assessment Unit. "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."
The IUCN Red List of Threatened Species is the world's most comprehensive information source on the global conservation status of plant and animal species. It is based on an objective system for assessing the risk of extinction of a species should no conservation action be taken.
Species are assigned to one of eight categories of threat based on whether they meet criteria linked to population trend, population size and structure and geographic range. Species listed as Critically Endangered, Endangered or Vulnerable are collectively described as Threatened.
The IUCN Red List contains information on the threats to the species, their ecological requirements, where they live, and information on conservation actions that can be used to reduce or prevent extinctions.
The IUCN Red List is a joint effort between the IUCN and its Species Survival Commission, working with its Red List partners BirdLife International; Botanic Gardens Conservation International; Conservation International; Microsoft, NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; Wildscreen; and Zoological Society of London.