A Few Frogs Have Survived the Fungus Epidemic

Forest and Bird, Issue 312, 1 May 2004, Page 6

A Few Frogs Have Survived the

Fungus Epidemic

—DAVE HANSFORD

igh in the Coromandel researchers have found pitifully few survivors of the chytrid fungus epidemic which has been killing the endangered Archey’s frog. But, they say, this is a start. As soon as the varsity term was over, Ben Bell headed to the cloudy tops of the Coromandel range and started turning over rocks. It was a long time before he found what he was looking for a glossy brown frog, no bigger than a matchbox. His study site at Tokatea Saddle yielded just two more — including, significantly, a juvenile — but he went away happy. He’d discovered the survivors of one of New

Zealand’s biggest ecological disasters of recent times. Coromandel was once a stronghold of Archey’s frog, one of the world’s most ancient, unique animals. Until 1996 that is, when Archey’s populations along the peninsula collapsed, then vanished before a lethal, invisible presence. Autopsies delivered the news everyone was dreading; chytrid fungus had spread from introduced Australian frogs into our native species. Dr. Bell, a herpetologist at Victoria University in Wellington, has been studying Archey’s frogs for over 20 years. He says chytrid fungus may have wiped out 85 percent of

known populations. A Department of Conservation science manager, Don Newman, sees little point in funding more research on the chytrid fungus, however. ‘We still don’t know how it kills frogs, and may never’ he says. ‘It’s here now; we just have to live with it. ‘Rather than DoC spending money on the disease — with no guarantee of an outcome — we're better off investing in ways to improve the chances of those frogs that are left. Things like more translocations (transferring frogs to safe refuges) to spread the risk, more intensive predator control — all those things that you would normally do to try and manage any threatened species.’ Over the last 200 million years, Archey’s frogs have faced many crises — Ben Bell says they even took the upheaval of the Coromandel gold rush in

their stride — but with their numbers now so perilously low, one more blow, such as predation by rats, could tip them over the edge. ‘There is a so-called critical limit, he says, ‘and an 85 percent crash must have taken them awfully close. But Ben Bell is heartened by the discovery that some Archey’s have survived the chytrid fungus; even more so by signs that they’re breeding again. (When frogs reach critically low numbers, they have trouble even finding a partner to mate with.) Ben Bell can’t be sure, but the hope is that the survivors of Coromandel might have some hereditary defence against the fungus, and will start filling the gene pool with a new, genetically resistant, population. ‘They’re down, but not out, he says.