Many species of frog have been killed off by the deadly amphibian chytrid fungus, Batrachochytium dendrobatidis — a fungus that is believed to have spread out of Africa and has now colonised all continents except Antarctica (where there are no frogs).

Faced with the advance of this deadly disease, as well as habitat loss, global warming and human-induced pollution of frog habitats, frogs and other amphibians are in serious decline worldwide.

The last ditch efforts of setting up ‘Amphibian Arks’ for there beleaguered species has begun! To counter the threat of mass frog extinctions, herpetologists called for every public zoo, aquarium and botanical garden across the world to rescue at least one species of frog. The recommendation is for each institution to adopt a species in danger of extinction and provide a long-term ‘home’ — mimicking their natural habitat requirements — for 500 or more frog species to build up a chytrid disease-free population. The suggestion, however fanciful, is the captive frogs will provide a population reservoir that — wait for it — can be reintroduced to the wild once their natural habitat is safe from the disease.

The initiative is being led by Amphibian Ark, an organisation set up to ensure the future of these threatened frogs. It estimates the cost of this grand venture at $US500 million.

The chytrid fungus was only identified in the mid-1990s as the cause of serious amphibian declines in the Americas, Australia and now also in Europe. Richard Gibson, curator of herpetology at the Royal Zoological Society of London, said: “Chytrid disease is responsible for huge population crashes and it is still spreading. Very few species are resistant to it and it’s becoming more and more widespread.”

Recently the fungus has been recorded in Japan and southern Europe. In Central and South America it has wreaked devastation, with dozens of frog species now no longer detectable and presumed extinct.

Amphibians form a vital component of the world’s ecological biomass, especially in tropical zones, where they are so numerous they play an important role in controlling insects that can cause disease in humans (arthropod-borne diseases). In terms of bio-prospecting, amphibians have also been very valuable as sources of new chemicals as an antibiotics, hormones, water-proofing compounds, analgesics (pain-killers) and anaesthetics.

David Obendorf

Conservation scientists estimate that 170 frog species have gone extinct in the past two decades. Yes that is their assessment, 170 separate frog species are no longer on planet Earth. They suggest that another 1900 species — out of a frog biodiversity of around 6000 species worldwide — are in decline and on the way out as well.