THE sharp decline in frog and toad populations worldwide has disturbed amphibian watchers (BBC Wildlife, March 1994). The findings of the Declining Amphibian Populations Task Force, a network set up by the Species Survival Commission of the World Conservation Union, reveal that amphibians are struggling for survival all the way from Australia and Europe to the US and South America. This could be caused by the amphibians' reduced access to water because of deforestation, building on wetlands and the pollution of watercourses and ponds.

However, at high altitude sites, the causes are more insidious. Herpetologists suggest that in mountainous areas, frog populations have been hit by a mixture of environmental stresses and a virus-weakened resistance. Some read this as a warning for other creatures, even human beings.