/ 4 March 2008

Counting the croaks

South Africa will be counting its frogs. Next month, frog guru Ann Mearns will launch a one-year frog census to gather data from around South Africa on how many frogs are left.

Mearns, a recipient of the United Nations Environmental Global 500 Role of Honour for her work on wetlands and frogs, says the ”national frog count” will help determine just how big a threat South Africa’s frog population faces.

”For this frog identification census we want info on all kinds of frogs — where they occur, what type, what numbers — from all over the country,” she says.

People are encouraged to start counting the frogs in their garden, and to learn more about them. They can then submit their data to Mearns.

This is a critical year for the world’s frog population — in conservation circles, 2008 has been declared the Year of the Frog because of the threat these amphibians face..

The Red List of Threatened Species and the Global Amphibian Assessment put about one-third of all amphibian species at high risk of extinction, and environmental organisations such as the WWF have warned that we are rapidly moving towards a potentially epidemic number of frog extinctions.

But there is a bigger reason why it should be in everyone’s business to protect frogs. Their catastrophic decline serves as a warning that the Earth is in a period of significant squalor.

”Frogs are indicators of the health of an ecosystem and can provide early warning of threats to other species, including ourselves,” says Mearns.

Environmentalists describe amphibians as ”the canaries in the coal mine”. Their highly permeable skins are sensitive to changes in water and air quality, and they can often point to a looming environmental disaster.

In South Africa, 110 frog species have been identified and three-quarters of these are found in wetlands. The giant bullfrog, one of the country’s most threatened frogs, is bound to come under the spotlight in the census.

This bullfrog, mainly found in Gauteng, is particular about its habitat, and will only breed when environmental conditions are conducive. The last known large-scale breeding event of giant bullfrogs took place 14 years ago, making this frog a prime candidate for local extinction, due to the province’s growing urban sprawl.