Extinction in our times - global amphibian decline: book review

Extinction In Our Times—Global Amphibian Decline
by James P. Collins & Martha L. Crump
Oxford University Press, 2009, 273 pp
Reviewed by Cécile Lepage

 In the early 1970s, Cynthia Carey was writing her doctoral dissertation on the physiological biology of boreal toads when a mysterious bacteria contaminated the Colorado West Elk Mountains population she was studying

Soon, she could only find dead carcasses. What she assumed was a strike of bad luck and a strictly local phenomenon was in fact occurring all over the world...reade more

James P. Collins and Martha L. Crump investigate this mystery through an academic work that reads like a detective story. Their book gives a lively account of how science unveiled the chytrid fungus, Batrachochytrium dendrobatidis, as a culprit for modern amphibian mass mortality.

They share several anecdotes such as Cynthia Carey’s. They then take us back to the 1989 First World Congress of Herpetology convened to understand and abate amphibian losses, and enumerate the varied hypotheses that were raised.

Even though the emergence of this virulent infectious disease, which puts an entire vertebrate class at risk, is at the core of their dissertation, the two Arizona professors place it in the much broader scope of the global biodiversity crisis. In their opening chapter, they discuss why the threat of extinction of a third of amphibian species matters, including aesthetic and ethical arguments.
 
The second chapter looks at how the conservation community has reacted. The authors outline the challenges and the interdisciplinary efforts that led to the fungus identification breakthrough.

The next two chapters cover the more well-established factors that have affected amphibian populations over the last century and caused declines: introduced species, trade, and land use change; whereas chapter five discusses more recent culprits such as contaminants, climate change, and, of course, emerging infectious disease.

Habitat alteration remains the greatest cause of extinctions, note the scientists, and it is all the more alarming as it impacts all taxonomic classes. Yet, the chytrid fungus crisis, even though it only targets Amphibians, is a pressing predicament as it defies past efforts to address the problem.

Chapters six and seven are devoted to a thorough discussion of the chytrid situation, reporting three case studies: the stream-dwelling frogs from northeastern Queensland, Australia, the boreal toads from the Colorado Rocky Mountains, and the montane frogs from Costa Rica and Panama.

In this last location, as the pathogen was spreading and reaching El Valle de Antón in 2006, scientists decided to remove from the wild 600 frogs of 35 species and house them in a conservation facility in Atlanta. This emergency step poses ethical, policy, and conservation questions that are discussed at length. It is to me the most gripping part of the book, as the authors reveal science and practice in the making.

The last three chapters focus on how the late 20th century challenges have compelled the scientific community to shift its methods. The authors write,

“Traditional conservation programs are designed to address readily identifiable and localized threats of habitat loss and human exploitation, but these strategies are likely to be of limited effectiveness in the face of the complex, synergistic, and subtle global threats of the 21st century. Entire ecosystems, such as coral reefs, or taxonomic classes, such as Amphibia, face large-scale declines and extinctions that require creative biological, legal, practical, and ethical solutions.”

Extinction In Our Times gives the reader, specialist or not, a glimpse into the new approaches the conservation field has devised to face this era of unfolding global change.