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Environment / Sustainability

'The trill is gone'

April 13, 2009

The decline of amphibian populations can be viewed as an alarm bell. Toads and frogs, who depend on both aquatic and terrestrial habitats, are 'conservation sentinels,' telling us much about the health of our ecosystems.

Water Center seminar
Thursday, April 16
noon to 1 p.m.
Lory Student Center, room 222 

Perhaps one of the more pleasant things about visiting a lake or marsh on a summer evening is the reep! reep! of frogs and the trill of toads. 

If you're a frog enthusiast, it may give you pause to hear that amphibians have more extinct and declining species than any other class of vertebrates in Colorado. 

According to CU Professor of Ecology and Evolutionary Biology Pieter Johnson, the existence of these amphibians is being threatened by land use patterns, biological invasions, and emerging diseases.  And their decline could be a foreshadowing of the decline of other species native to Colorado.

Seminar: Why are amphibian populations declining?

On Thursday, April 16, the CSU Water Center will host: Complexity in conservation: Understanding amphibian population declines in Colorado by Pieter Johnson, Ph.D., Ecology and Evolutionary Biology, University of Colorado.

Amphibian populations are at the forefront of the global biodiversity crisis, with more extinct or declining species than any other class of vertebrates. The causes of such declines are diverse and often interact through complex mechanisms, which may be difficult to disentangle from monitoring data alone.  

Addressing ecological changes

"In cooperation with local, state and federal agencies," Johnson said, "We are combining information from historical records (1900-1990), contemporary sampling of native and non-native amphibians, and epidemiological data to evaluate the current status of Colorado amphibians and the likely causes underlying their declines, with a focus on the roles of invasive bullfrogs (Rana catesbeiana), the infectious chytridiomycete (Batrachochytrium dendrobatidis) and their interactions."

Because amphibians depend on both aquatic and terrestrial habitats, they act as conservation sentinels for a broad range of native species in Colorado, underscoring the importance of identifying and addressing the ecological changes underlying their disappearance. 

About Pieter Johnson 

Johnson is an Assistant Professor in the Ecology and Evolutionary Biology Department at the University of Colorado, Boulder. He received a Bachelor of Sciences degree from Stanford University in 1998 and a Ph.D. in freshwater ecology from the University of Wisconsin, Madison, in 2006. He is also a Research Fellow with the David and Lucille Packard Foundation.

Johnson’s research focuses on two pervasive forms of biological change in aquatic ecosystems: disease emergence and species invasions. Both have important consequences not only for individuals and populations but also for entire ecological communities and ecosystem services.

Since 1996, Johnson has investigated the causes and consequences of limb deformities in North American amphibians, including missing, extra and severely misshapen limbs. This research has highlighted the importance of Ribeiroia ondatrae, an emerging trematode pathogen that is highly sensitive to environmental change. 

Learn more

To read more on these projects and on Pieter Johnson, please visit his website.


Contact: Reagan Waskom
E-mail: Reagan.Waskom@colostate.edu
Phone: (970) 491-6308