Survey and Assessment of Northern Leopard Frog (Rana pipiens) Populations in Washington State

Abstract

Although the northern leopard frog (Rana pipiens) is among the most widely dis- tributed amphibians in North America, population declines have been reported from several regions including the Pacific Northwest. We determined the historic distribution of the species in Washington State and conducted surveys to assess its current status. We obtained records from herpetological collections and solicited reports of sightings from biologists. We examined museum specimens to verify identification accuracy and evaluated sightings and solicited pho- tographs to validate sight records. The records were compiled into 17 geographic rep- resenting clusters of locations where R. pipiens records occurred within 8 km of one another. All 17 areas are located in eastern Washington. We conducted field surveys in 16 of the 17 areas. Extant populations of R. pipiens were detected at only 2 areas. Rana pipiens appears to have been extirpated from most of its historic range in Washington, a phenomenon that has parallels in adjacent states and Canadian provinces.