Extinction .in

World's reptiles at risk of extinction

 

 
Many lizards are under threat, including the mountain horned agama of Sri Lanka
 

Almost a fifth of the world's reptile species are at risk of extinction, according to scientists.

Research led by the Zoological Society of London found that the future of 19% of the world's reptiles are threatened.

Conservation experts also confirmed that 47% are vulnerable and highlighted the possible extinction of three species.

The figures are based on a random sample of 1,500 of the world's reptile species.

"It's essentially an election poll set up - using this sample to give an example of how reptiles are doing as a whole," explained Dr Monika Bohm, lead author of the study published in the journal Biological Conservation.

The study was made in conjunction with 200 experts from the International Union for the Conservation of Nature's Species Survival Commission.

Reptiles are a group of vertebrates that includes
turtles, tortoises, snakes, lizards, crocodiles and amphisbaenians - commonly
known as worm lizards. Tuataras, lizard-like animals found only in New Zealand
are also included.

There are an estimated 9,500 different reptile species in the world.

"Reptiles can really be important in natural food webs: they're really
important as predators as well as prey," said Dr Bohm.

"The risk is - if you lose a really important food source you can change food
webs quite dramatically."

Although some species, including the tuatara, have survived relatively
unchanged for millions of years, Dr Bohm pointed out that reptiles can often be
"indicators" of environmental problems.

"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," she said.

"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."

Under pressure

The study highlighted that levels of threat to the diverse group of animals
are particularly high in tropical regions due to pressures from agriculture and
logging.

One species previously listed as Critically Endangered is the jungle runner
lizard Ameiva vittata, which had only ever been recorded in one part of
Bolivia.

But, prompted by the destruction of its habitat, two recent searches for the
animal were unsuccessful, causing conservationists to question its future
existence.
 

Unique pig-nosed turtles have been over-harvested in Papua New Guinea

In Haiti, six of the nine species of Anolis lizard
studied also had an elevated level of localised extinction due to extensive
deforestation.

Freshwater turtles were also flagged as a considerable concern. The study
estimated 50% were at risk of extinction, and 30% of freshwater reptiles are in
danger of disappearing as a whole.

Dr Bohm hopes the study's results will focus attention on their plight.

"With turtles, what's quite often the case is they are affected by harvesting
and they're quite often used for food or the pet trade," she told BBC
Nature.

The survey is one of many that aims to provide an indicator of biodiversity
both now and over time, in an effort to make such research more
collaborative.

"This gives us an indication of how reptiles are faring and we can compare
this to other species groups."

"We can then find out if there's a similar picture across all of them or if
there are some that are particularly threatened," Dr Bohm commented.

"It's more of a drive to really pool information rather than everybody doing
their own thing... really working together, getting it out there and giving it
more emphasis."