Are We in the Midst of the Sixth Mass Extinction? A view from the world of amphibians
Guest Speaker: Vance Vrendenburg
Thursday February 18th, 7:30pm
Many scientists argue that we are either entering or in the midst of the sixth great mass extinction. Intense human pressure, both direct and indirect, is having profound effects on natural environments. SF State Professor, Vance Vrendenburg presents a view from the world of amphibians.
The amphibians—frogs, salamanders, and caecilians—may be the only major group currently at risk globally. A detailed worldwide assessment and subsequent updates show that one third or more of the 6,300 species are threatened with extinction.
This trend is likely to accelerate because most amphibians occur in the tropics and have small geographic ranges that make them susceptible to extinction. The increasing pressure from habitat destruction and climate change is likely to have major impacts on narrowly adapted and distributed species. Dalamanders on tropical mountains are particularly at risk.
A new and significant threat to amphibians is a virulent, emerging infectious disease, chytridiomycosis, which appears to be globally distributed, and its effects may be exacerbated by global warming. This disease, which is caused by a fungal pathogen and implicated in serious declines and extinctions of >200 species of amphibians, poses the greatest threat to biodiversity of any known disease.
Our data for frogs in the Sierra Nevada of California show that the fungus is having a devastating impact on native species, already weakened by the effects of pollution and introduced predators.
Vance Vrendenburg, SF State Professor, presents a general message from amphibians is that we may have little time to stave off a potential mass extinction. Learn more about his work at his website: http://web.me.com/vancevredenburg/Vances_site/Home.html