Reptile Use of Shrubsteppe and Conservation Reserve Program Habitats in Eastern Washington, USA. (DRAFT)

While shrubsteppe vegetation once comprised the dominant vegetative cover in eastern Washington (Daubenmire 1970), it now occurs in less than 40% of it’s historic Washington range, and much of it is degraded, fragmented, and/or isolated from other remnants (Dobler et al. 1996, Jacobson and Snyder 2000). Primary factors in shrubsteppe loss include type conversions for crop or livestock production (Buss and Dziedzic 1955, Vale 1974, Swenson et al. 1987, Vander Haegen et al. 2001), inundation by hydroelectric water impoundments (Howerton 1986), fragmentation by roads, transmission lines, energy development, canals (Noss et al., 1995, Hann et al., 1997, Vander Haegen et al. 2001), and altered vegetative structure and species composition resulting from over grazing, exotic plant invasion, and altered fire frequency (Yensen et al. 1992, Vander Haegen et al. 2001).

Shrubsteppe loss and degradation has had profound negative effects on shrubsteppeassociated wildlife. Population declines have been documented for numerous bird and mammal species, e.g., sage-grouse (Centrocercus spp.), Brewer’s sparrow (Spizella breweri), sage sparrow (Amphispiza belli), sage thrasher (Oreoscoptes montanus; Connelly et al., 2000, Knick and Rotenberry 2002, Vander Haegen et al., 2000), pygmy rabbit (Brachylagus idahoensis, WDFW 1993, USDI 2003), and Washington ground squirrel (Spermophilus washingtoni, Betts 1999, Finger et al., In Press).

Many amphibian and reptile species are associated with shrubsteppe and have declined as well (Vander Haegen et al. 2001). The sharptail snake (Contia tenuis) and striped whipsnake (Masticophis taeniatus) are Washington state candidates for threatened status, the night snake is a state monitor species; the sagebrush lizard (Sceloporus graciosus) is a federal species of concern, and the northern leopard frog (Rana pipiens) is endangered in Washington State and has been petitioned for listing at the federal level (Anonymous 2006). For many of these species, population declines associated with habitat loss are suspected.

Established in 1985 and originally focused on economic assistance, the Conservation Reserve Program (CRP) paid farmers to remove farm and range land from production and plant permanent vegetative cover to conserve soil (Bidwell and Engle 2005). Early enrollments didn’t consider wildlife needs, but as recognition of the potential benefits to wildlife increased, later enrollments began considering wildlife habitat needs and other environmental factors (Hyberg 2005). In effect, the CRP constitutes a national effort to increase habitat for grassland and shrubsteppe wildlife (Hyberg 2005); and is the largest habitat improvement project in eastern Washington. In Washington, over 405,000 ha (1 million ac) of agricultural land has been planted to non-native grasses, native grasses, forbs and shrubs under the CRP. Despite the potential of CRP land as amphibian and reptile habitat, we are aware of no studies that have examined use of CRP lands by these taxa.

Our objectives were therefore to evaluate the potential role of CRP in conservation of amphibians and reptiles in Washington. Specifically, we wished to compare amphibian and reptile distributions in CRP lands with those in nearby native shrubsteppe, and compare amphibian and reptile patterns of occurrence in CRP lands of different ages and set in different landscape contexts to provide information that will benefit management of CRP in Washington to benefit shrubsteppe associated amphibians and reptiles.