Open Eye: It's time to worry about the frogs

What does the declining population of amphibians mean? Yvonne Cook reports

Where are the frogs going? The fate of amphibians has been worrying experts worldwide over the last nine years. And evidence is emerging that more of us should be worried too.

It first became apparent in 1989, that species of frogs and toads had started to vanish, quite suddenly, in locations as far apart as South America, Australia and the Pacific northwest of the USA.

More worryingly, they were disappearing not only from areas where their habitats were under threat, but from nature reserves, national parks and other areas set up to protect wildlife.

Out of the experts' concern was born the Declining Amphibian Populations Task Force, a global organisation of scientists and volunteers, which since 1991 has been based at the Open University in Milton Keynes. Tim Halliday, Open University Professor in Biology, is its international director.

"The declining amphibian phenomenon seemed to be telling us two things. First, it cast serious doubt on the assumption that animals can be protected by setting up reserves. Second, it suggested that amphibians were subject to some adverse environmental process that affects them on a global scale," said Tim.

The second conclusion was highly disputed, with some experts claiming the declines were due simply to natural population fluctuations.

As the Task Force put together data collected from its 3000-plus members and 100 regional groups across the world, certain things became clear: the declines were occurring globally, but not in all regions of the world; and while many declines could be explained by human activities such as deforestation, draining of wetlands and changes in farming practices, some could not.

Attention began to focus on environmental factors, and disease. Amphibians - frogs, toads, newts and salamanders - are found on every continent except Antarctica. The American continent is particularly rich in species. In one reserve in Costa Rica alone, 20 out of 50 frog species have apparently become extinct within the last 20 years.

Tim Halliday calls amphibians an 'environmental barometer'. "Amphibians are particularly dependent on clean water. They have very thin skins, through which water passes easily, so they are extremely susceptible to pollutants such as herbicides and pesticides."

But the evidence from Task Force data was pointing to another factor. This came into the limelight in June this year with the publication of a paper which pinned responsibility for recent dramatic declines on a fungal infection, chytridiomycosis, which appears to be a new disease.

What surprised scientists, said Tim, was that dead and dying frogs found as far apart as Australia and Central America, were suffering from this same disease.

"One possibility is that this disease has been carried from one place to another by some agent - people, or fish, for example. The other is that it's one of those diseases that exist in the amphibian population worldwide, but amphibians have only just become susceptible to it. This would point to something in the environment which is reducing their resistance to the disease."

Parallels for this exist in patterns of human disease - some have suggested the rising incidence of asthma could be due to a reduction in people's level of resistance. On a more mundane level, we all carry the virus that causes cold sores around with us, but it is only when we're tired and "run down" that it strikes.

So why should amphibians be becoming more susceptible? More evidence is needed before this question can be answered, but the suspicion that environmental stress may play a part is strong.

Possibilities include chemical pollution but also global warming or the reduction of the earth's ozone layer. It is known from other work that some amphibian species are vulnerable to increased levels of ultraviolet radiation caused ozone reduction.

"People in different parts of the world are trying to raise money for a rapid reaction force, so that if there are reports of dead or dying frogs anywhere we can get someone there quickly to investigate," said Tim.

"At the moment we don't know how widespread it is, or what percentage of frogs are affected." Whether it could affect newts or salamanders is not known either, nor exactly how it is spread, although the Task Force has recently produced guidelines for anyone involved in amphibian research to try and prevent their inadvertently spreading the disease from one site to another.

The good news is that no cases of the disease have yet been found in Britain. As well as collecting data, the Task Force is concentrating on raising awareness - and money, to fund research into potential causes of decline. But its time is running out - collecting evidence must ultimately be translated into action, says Tim.

"We will probably produce a final report for the year 2001, which is going to be a big year for biodiversity, and then we are going to stop what we're doing. We'll hand over to other people what we have found, and let them do what they want to do with it.

"The hope is the Task Force will be followed by a global conservation organisation. In the meantime, perhaps we should all be grateful to the frogs."

Tim says: "Because of their great sensitivity to changes in habitats they may be giving us early warning of major and widespread environmental change. And the factors that have been shown to affect amphibians, like solar radiation and chemical contamination, affect all forms of life, including humans."

More information about the Declining Amphibian Populations Taskforce is available on: www.open.ac.uk/OU/Academic/Biology/J_Baker/JBtxt.htm.

The taskforce's quarterly newsletter FROGLOG is also available on the Web; or write to:

Professor Tim Halliday

Department of Biology, Open University, Walton Hall, Milton Keynes MK7 6AA, UK

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA special investigation by Andy McSmith
Arts and Entertainment
Books should be for everyone, says Els, 8. Publisher Scholastic now agrees
booksAn eight-year-old saw a pirate book was ‘for boys’ and took on the publishers
Life and Style
Mary Beard received abuse after speaking positively on 'Question Time' about immigrant workers: 'When people say ridiculous, untrue and hurtful things, then I think you should call them out'
tech
Life and Style
Most mail-order brides are thought to come from Thailand, the Philippines and Romania
life
News
i100
Life and Style
tech
Voices
Margaret Thatcher, with her director of publicity Sir Gordon Reece, who helped her and the Tory Party to victory in 1979
voicesThe subject is being celebrated by the V&A museum, triggering some happy memories for former PR man DJ Taylor
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs Education

Ashdown Group: Systems Engineer - Windows, Linux - Central London

£40000 - £48000 per annum + Benefits: Ashdown Group: Systems Engineer - Windo...

Guru Careers: Product Training Specialist / Software Trainer

£25 - 32,500K (DOE) + Excellent Benefits: Guru Careers: We are seeking a Produ...

Recruitment Genius: Unqualified NVQ Assessors - Health, Social Care & Management

£16000 - £22000 per annum: Recruitment Genius: This award winning independent ...

Recruitment Genius: Telesales Advisor - OTE £30,000

£15000 - £30000 per annum: Recruitment Genius: This is a fantastic opportunity...

Day In a Page

General Election 2015: Chuka Umunna on the benefits of immigration, humility – and his leader Ed Miliband

Chuka Umunna: A virus of racism runs through Ukip

The shadow business secretary on the benefits of immigration, humility – and his leader Ed Miliband
Yemen crisis: This exotic war will soon become Europe's problem

Yemen's exotic war will soon affect Europe

Terrorism and boatloads of desperate migrants will be the outcome of the Saudi air campaign, says Patrick Cockburn
Marginal Streets project aims to document voters in the run-up to the General Election

Marginal Streets project documents voters

Independent photographers Joseph Fox and Orlando Gili are uploading two portraits of constituents to their website for each day of the campaign
Game of Thrones: Visit the real-life kingdom of Westeros to see where violent history ends and telly tourism begins

The real-life kingdom of Westeros

Is there something a little uncomfortable about Game of Thrones shooting in Northern Ireland?
How to survive a social-media mauling, by the tough women of Twitter

How to survive a Twitter mauling

Mary Beard, Caroline Criado-Perez, Louise Mensch, Bunny La Roche and Courtney Barrasford reveal how to trounce the trolls
Gallipoli centenary: At dawn, the young remember the young who perished in one of the First World War's bloodiest battles

At dawn, the young remember the young

A century ago, soldiers of the Empire – many no more than boys – spilt on to Gallipoli’s beaches. On this 100th Anzac Day, there are personal, poetic tributes to their sacrifice
Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves

Follow the money as never before

Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves, reports Rupert Cornwell
Samuel West interview: The actor and director on austerity, unionisation, and not mentioning his famous parents

Samuel West interview

The actor and director on austerity, unionisation, and not mentioning his famous parents
General Election 2015: Imagine if the leading political parties were fashion labels

Imagine if the leading political parties were fashion labels

Fashion editor, Alexander Fury, on what the leaders' appearances tell us about them
Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

The architect of the HeForShe movement and head of UN Women on the world's failure to combat domestic violence
Public relations as 'art'? Surely not

Confessions of a former PR man

The 'art' of public relations is being celebrated by the V&A museum, triggering some happy memories for DJ Taylor
Bill Granger recipes: Our chef succumbs to his sugar cravings with super-luxurious sweet treats

Bill Granger's luxurious sweet treats

Our chef loves to stop for 30 minutes to catch up on the day's gossip, while nibbling on something sweet
London Marathon 2015: Paula Radcliffe and the mother of all goodbyes

The mother of all goodbyes

Paula Radcliffe's farewell to the London Marathon will be a family affair
Everton vs Manchester United: Steven Naismith demands 'better' if Toffees are to upset the odds against United

Steven Naismith: 'We know we must do better'

The Everton forward explains the reasons behind club's decline this season
Arsenal vs Chelsea: Praise to Arsene Wenger for having the courage of his convictions

Michael Calvin's Last Word

Praise to Wenger for having the courage of his convictions