USGS biologists preparing to collect amphibian samples at Kettle Tarn in Rocky Mountain National Park, CO (circa 2001). Hydrologists and biologists are working together to understand the reasons for recent amphibian declines.
USGS biologist with an amphibian (boreal toad) that will be weighed, measured, and released after being fitted with a small magnetic tag for later reidentification (circa 2001).
USGS scientist measuring the pH of Paine Run in Shenandoah National Park, Va. (circa 2002). Water-quality data is being used to help provide the context for the analysis of amphibian population data.