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Amphibian Study

Prior to the Las Vegas Wash Amphibian Survey from April 2004 to October 2005, the last known studies to be conducted on anurans (frogs and toads) in the Wash were in the 1970s. The purpose of this study was to investigate the current diversity of anurans along the Wash using a visual encounter survey methodology. This baseline inventory will help fill a 30-year gap in monitoring and study of anuran species diversity in the Wash. After the baseline data has been analyzed, we will have the tools needed to make decisions that incorporate specific management actions, which could reduce threats to these species and to propose site-specific conservation actions if needed.


Visual encounter surveys were used to determine the presence of amphibians in the Wash. Studies such as these have been used in this region to survey for amphibian populations. The surveys were conducted at night when adult anurans are more easily detected. Surveys consisted of visual and audio searches of aquatic habitats close to shorelines and terrestrial habitats within several meters of water. The surveys were generally conducted by two individuals using both headlamps and high intensity flood-lights.

Woodhouse's Toad

Audio searches for calling individuals were used to identify breeding sites. Surveys were conducted approximately three to five nights of each month. This allowed the potential for detection of early breeding anurans, such as the Pacific Treefrog, and other species that may not breed until the summer monsoons, such as spadefoot toads.

Visual encounter surveys revealed the presence of two anurans using the Wash. They are the bullfrog and the Woodhouse’s Toad. Staff biologists have visually seen the Pacific Treefrog, but not during the visual encounter surveys.

Additional Information: Las Vegas Wash Amphibian Survey, 2004-2005

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Las Vegas Wash Project Coordination Team • 100 City Parkway, Suite 700 • Las Vegas, NV 89106 • (702) 822-3300