Do Amphibian Deaths Signal the Coming of a Sixth Mass Extinction?
If the rapidly depleting amphibian populations are any indication, we could be in for another mass extinction. That's the conclusion of a new study published in the Proceedings of the National Academy of Sciences, which finds that humans are worsening the impacts of climate change and disease on frogs and their fellow amphibians -- to the point where they are vanishing at an unprecedented, alarming speed.
The fatal infectious disease in question, chytridiomycosis, is caused by an aquatic fungus that only targets amphibians and is able to jump from one species to the next; it is believed to have already wiped out over 200 species. Image from AmphibiaWeb
Because of their hardiness -- they have survived four past mass extinctions -- amphibians are considered a harbinger of future biodiversity. The fact that many have gone extinct in recent years has caused great concern among the scientific community, leading many to wonder if the next mass extinction is almost upon us -- and if there is still time to avert it.
The study's authors, Vance Vredenburg of San Francisco State University and David Wake of UC Berkeley, believe the amphibians' disappearance is telling us something about our future and that of millions of other species. One key research focus is studying the ecology of chytridiomycosis, whose mode of action and life cycle remain a mystery. Understanding it may help stop, or at least control, future outbreaks. On a related note, another fungus called Ug99, which my colleague Karin Kloosterman wrote about last year, has been devastating global wheat crops -- and could destroy up to 70% of them -- showing that the spread of virulent pathogens isn't limited to just animals.
Vredenburg, who devotes his research to the ecology and evolution of amphibians, is the co-founder of AmphibiaWeb, a bioinformatics project that seeks to promote the conservation of the planet's amphibians. Amphibian Ark, an international organization with a similar mission (whose efforts I profiled here), provides another valuable resource for people interested in conservation and management efforts.
While it does not pose an immediate threat to other organisms, there is always the concern that it could evolve into a different form that could be transmissible to humans or other vertebrates. Because climate change is helping spread infectious diseases in many warmer regions of the world, devising an effective strategy to contain such pathogens could help forestall a major ecological crisis.
More about our beleaguered amphibian friends