Thursday, February 28, 2008

Tomorrow is Leap Day

Canyon Treefrog, Hyla arenicola. From Fred in Arizona.


Tomorrow, February 29, is Leap Day, the kick-off for the Year of the Frog, a recognition that on a planetary basis, frogs are at risk and that a major effort is needed to prevent mass anuran extinction.

In the late 1980s, reports of shocking amphibian declines, including losses of once huge populations and entire species, were coming from disparate parts of the world. By the early 1990s, herpetologists were creating organizations to monitor the declines, and discuss causes and measures. Suspected culprits were widescale habitat loss or disruption, egg and/or larval death due to excessive UVB from a thinning ozone layer, waterborne pesticides and other toxins, and introduced invasive animal and plant species. The most chilling development was the discovery that a fungus, Batrachochytrium dendrobatidis was spreading around the world. An early step in this pandemic was the intercontinental dissemination of African clawed frogs, Xenopus laevis, which since 1934 had been used in human pregnancy assays (Weldon, et al., 2004). These frogs were also, at least for a while, common in the aquarium trade, thus potentially introduced to any body of water within or near any city. The fungus is not picky, any frog will do, and once within native populations could be further spread by 9-year-old boys catching and releasing pets, the use of frogs as fishing bait, and who knows what else. The footwear of herpetologists, travelling from one far-flung site to another? The fungus inhabits the outer keratinized layers of the epidermis, and causes skin sloughing, ulcers, and rapid general decline in frogs (Berger et al., 1999), and deformation of oral disks in tadpoles (Fellers et al., 2001).

Find out more about frogs and frog conservation at the Amphibian Specialist Group, and have a Happy Leap Day.

References

Berger L, R. Speare, A.D. Hyatt. 1999. Chytrid fungi and amphibian declines: overview, implications and future directions. In: Campbell A. (ed) Declines and disappearances of Australian frogs. Environment Australia: Canberra. 1999: 23-33.

Fellers, G.M., D.E. Green, and J.E. Longcore. 2001. Oral chytridiomycosis in the mountain yellow-Legged Frog (Rana muscosa). Copeia 2001: 945-953.

Weldon, C., L.H. du Preez, A.D. Hyatt, R. Muller, and R. Speare 2004. Origin of the amphibian chytrid fungus. Emerging Infectious Diseases 10: 2100-2105.


3 comments:

pookie said...

That has got to be the coolest photo of a froggie I've ever seen. He looks like how I feel. Thanks, Fred.

Hugh said...

Fred has the coolest critters at his place.

Thanks, Fred, and thanks, Pookie.

BerryBird said...

Thanks for posting about this, Hugh. I hadn't heard about Year of the Frog, so I'm off to do some reading.