Frogs' jump to oblivion 'a bad portent'

A worldwide decline of frogs could point to serious environmental problems, a University of Otago amphibian expert said at the beginning of this International Frog Week.

"They've been likened to canaries in the coalmines; if something is going on with the frogs then it's a sure sign there's something going on in the environment," zoology senior teaching fellow Dr Phil Bishop said.

More than a decade ago, almost 1400 amphibian experts gathered for a conference at the University of Kent, in England, and began to compile anecdotal evidence of the decline.

Since then research into the problem has begun in earnest. As a result experts have concluded that frog populations around the world are declining.

Dr Bishop, New Zealand chairman of the Declining Amphibian Population Task Force, said: "People realised something funny was happening to frogs and we set up a taskforce to find out if this was a real thing."

He said several theories to explain the decline had been considered, though not agreed on.

Suspects include increased ultra-violet rays as a result of the depleting ozone layer, increased exposure to pesticides and herbicides and exposure to a chytrid fungus, which may be proving fatal.

Dr Bishop, who is co-ordinating Frog Week in New Zealand, said frogs were particularly vulnerable to changes in the environment because their moist skin easily absorbed water and they were vulnerable to air changes. Any pollutants could therefore have a serious impact. Frogs also played a key role in the ecosystem.

"All creatures have a role to play in the environment. I liken it to the rivets on a plane; you can lose a certain number, but if you lose a critical number the plane will crash. We don't know how many we can lose before the ecosystem crashes."

New Zealand native frogs also appeared to be declining, though they were secretive by nature and therefore difficult to track.

"It is a real concern if there is something happening to our native frogs because they are the most ancient group of amphibians and are very close to the first frogs that evolved," Dr Bishop said.

The frogs had no eardrum and did not croak to communicate. New Zealand was the only place this kind of frog lived.

"We want to try and increase people's awareness of the plight of the frogs and to realise how important they are to the ecosystem and how important New Zealand frogs are to the rest of the world."

Dr Bishop said people should be careful when handling frogs to make sure that if they gathered them from a pond, they returned them to the same pond to avoid transferring diseases.

Frogs from pet shops should never be returned to the wild for the same reason.

- NZPA

Department of Conservation


Further reading
nzherald.co.nz/environment