Retorts

Frogs Fight On

While concerns about "Frog Fadeout" [April 1996] are real, portions of your article may be a bit misleading.

Although the Australian golden bell frog, once quite common in large portions of New South Wales, is now known to breed only in very few localities there, populations still appear abundant in parts of Victoria. The green frog, another Australian species now common throughout New Zealand, similarly appears to have suffered a massive range contraction except in southern Victoria.

On the other hand, I am unaware of any evidence that the whistling tree frog is declining in Australia, although the status of populations at higher elevations is unknown. High levels of UV radiation have been suggested as a possible cause of mortality of eggs of some frogs, but most researchers attribute declines to introduced predators or disease.

Although occasional reports suggest decreased numbers of native New Zealand frogs in some localities in some seasons, no overall trends emerge to suggest that these frogs are decreasing in number. Given the global nature of frog declines, clearly we need to maintain vigilance over our native species, but at present there is no reason to be alarmed about their prospects.

Two of the Australian frogs do seem to be doing better here than in large portions of their homeland. I believe that we have a responsibility to monitor their status and work for their protection here. Moreover, comparisons of populations of these frogs in New Zealand with extant populations in Australia should afford us an excellent opportunity to investigate possible causes of global amphibian decline.

Bruce Waldman, Department of Zoology, Canterbury University