Page last updated at 14:56 GMT, Friday, 26 September 2008 15:56 UK

Bleak outlook for Europe's toads

By Mark Kinver
Science and environment reporter, BBC News

Common toads in a mating ball (Image: Trent Garner/ZSL)
Even common toads are feeling the heat, researchers warn

More than half of Europe's amphibians could be extinct by 2050, a team of UK researchers has warned.

Climate change, habitat destruction and disease were the main factors threatening the species' long-term survival, they added.

Scientists from the Zoological Society of London (ZSL) said creatures in Italy and Iberia were at most risk.

A recent global assessment found that a third of all amphibians were at risk of being wiped off the face of the planet.

The findings were presented at an event hosted by naturalist Sir David Attenborough to highlight the plight of Europe's amphibians.

"Amphibians are the lifeblood of many environments, playing key roles in the functions of ecosystems," Sir David said.

"It is both extraordinary and terrifying that in just a few decades we could lose half of all these species."

Bleak outlook

Outlining the team's findings, ZSL research fellow Trent Garner said climate change was likely to have a dramatic impact on the conditions the creatures needed to survive.

Midwife toad (Image: Jaimes Bosch)
We need to reduce carbon emissions, but also address other pressing factors including habitat destruction and spread of diseases
Helen Meredith,
ZSL EDGE programme

"Published projections show that climate change alters amphibians' habitats, so we expect a large number of species to be faced with loss of habitat and, ultimately, extinction," he observed.

"A large number of Europe's amphibians are endemic to Mediterranean islands, and these are the areas that are forecast to get much warmer and much drier.

Dr Garner said that many species had specific physiological requirements, such as the Sardinian brook newt (Euproctus platycephalus).

"Whenever we go out and sample it, we are finding in waters that are 14-15C at the warmest.

"So, a few degrees of temperature change could have a substantial effect on the animal."

He said that a large proportion of Europe's amphibians were endemic to the Iberian and Italian peninsulas.

"You have got the situation again where they are surrounded by water, and if they try to disperse northwards, they are going to run into the Pyrenees or Alps.

"Those animals, to a large extent, trapped on those two peninsulas. They have got nowhere to go if climate change moves forward as projected."

However, he warned that amphibians in other parts of Europe also faced an uncertain future.

"In the UK, we are already seeing common toads losing condition and experiencing reduced survival.

Olm (Image: Arne Hadali)
Water pollution is threatening olms, which are cave-dwelling salamander

"As climate change continues to impact habitats, the situation gets far worse for these native species."

As well as the climate threat, the researchers warned that two infectious diseases - a chytrid fungus and ranavirus - were also a serious threat to the animals' long-term survival.

In 2006, an assessment of the world's 5,743 known species of amphibians concluded that one third of them were under threat. In comparison, just 12% of bird species and 23% of mammals were listed as threatened.

The Global Amphibian Assessment also showed that at least 43% of all species were experiencing declines, In contrast, fewer than one percent showed signs of population increases.

Helen Meredith, amphibians co-ordinator for ZSL's Evolutionarily Distinct and Globally Endangered (EDGE) programme, warned: "There is no time to waste if we are to prevent further species loss.

"We need to reduce carbon emissions, but also address other pressing factors including habitat destruction and spread of diseases."

Survival lifeline

One possible lifeline, Dr Garner told BBC News, came in the guise of an organisation called Amphibian Ark.

"It is an organisation that's trying to mobilise the world's zoological gardens to develop captive-breeding programmes of species that are at a high risk of the threats facing amphibians.

"One of the nice things about amphibians is that they are small, so getting them into captive-breeding programmes is not like getting rhinos or hippos in one."

But Dr Garner said that this approach also had problems to overcome.

"There are not a lot of amphibian captive breeding specialists, especially in Europe; there is a need to train people and get them into zoos and positions to do this kind of work.

"And, of course, there is a need for funding to develop the facilities, because these need to be bio-secure; we need to take into account infectious diseases when we build these facilities."

Dr Garner said that although the individual creatures were small, they played a key role in maintaining the balance within ecosystems.

"As early as the 1970s, there were papers being published showing that the amount of biomass that amphibians represent in ecosystems was substantial.

"You cannot destabilise that component of an ecosystem without there being knock-on effects.

"They provide food for a lot of invertebrates, and vertebrates too. Amphibians also help keep invertebrate populations down as well."

He added that science had not even begun to tap the full potential of possible drugs and medicines that could be derived from the creatures.

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