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12Land Protection Plan—Wyoming Toad Conservation Area, Wyoming

mack 1979, Gregory et al. 1991, Poff et al. 2011). It is estimated that about 90 percent of the total wildlife species in Wyoming use wetlands and riparian habitats either daily or seasonally and about 70 percent of Wyoming bird species depend on wetlands or riparian areas (Nicholoff 2003). Riparian areas are important migration and dispersal corridors that enable species to readily move through harsh grassland and desert environments.

Many bird species use the riparian corridors of the Laramie Plains during spring and fall migration, and many others stay through the summer to breed. Insect production is high in riparian communities, leading to locally abundant concentrations of insectivorous birds and bats. In the Laramie Plains, narrow-leaf cottonwoods and several willow species are adapted to the natural flow dynamics of the streams and rivers in the area, but throughout the west, many riparian areas have declined because of widespread damming and water diversion. Many riparian and wetland areas within the Laramie Plains now support a variety of exotic and invasive plants, such as Russian olive and Canada thistle. Both the ranching and wildlife conservation communities have devoted significant resources in efforts to control invasive plants in the region.

Grasslands and Shrublands

The composition and structure of grasslands are affected by short growing seasons as well as frequent and occasionally intense natural disturbances such as drought, fire, and herbivory (Nicholoff 2003). Between 1950 and 1990, the grasslands west of the Mississippi River declined by 27.2 million acres (Conner et al. 2001). The greatest threats to grassland and shrubland ecosystems are oil and gas development, increasing urban and agricultural development, and invasive species. Usually dominated by grazers, grasslands are known to support large numbers of wildlife and have a significant influence on the plant and animal composition of grassland habitats (WGFD 2010).

In Wyoming, prairie grasslands usually occur below the elevation of 7,000 feet, but the Laramie Plains, which is at approximately 8,000 feet, contains the highest elevation grasslands in Wyoming (Knight 1996). Grasslands in Wyoming are characterized by interspersed short- and mixed-grass prairies and are typically unsuitable for farming; however, they provide an abundant grazing resource for cattle and sheep. Most of Wyoming’s prairie grasslands are privately owned (WGFD 2010).

Prairie grasslands support an impressive array of wildlife. White-tailed prairie dogs thrive in recently disturbed areas, living in large colonies, digging burrows, and keeping the surrounding vegetation short. Their burrows and open patches of ground create habitat for other wildlife species, including the black-footed ferret, long-tailed weasel, swift fox, mountain plover, and burrowing owl (Kotliar et al. 1999, Kotliar 2000, WGFD 2010). Prairie dogs also provide a prey base for species such as black-footed ferret, ferruginous hawk, and golden eagle.

FWSPronghorn in the uplands of the Laramie Plains.

Wyoming once represented the western edge of the range for many species such as mountain plover, ferruginous hawk, swift fox, and pronghorn. Intensive conversion of grassland in the Great Plains resulted in the loss of these habitats outside of Wyoming. Populations in Wyoming have remained largely intact, and the core of these species’ distributions is now considered to be in Wyoming (WGFD 2010).

Shrublands in the Laramie Plains are dominated by greasewood, saltbrush, and rabbitbrush, as well as some sagebrush. Shrublands are often intermixed with the prairie grassland community. Greasewood shrubland and saltgrass meadows are characteristic of the playas and other comparatively wet depressions (Knight 1996) that are scattered across the Laramie Plains. Shrubland communities provide habitat for a suite of wildlife species, including golden eagle, prairie falcon, mountain plover, Brewer’s sparrow, jackrabbit, coyote, bobcat, badger, pronghorn, and mule deer. Pronghorn are more common than deer in salt-desert shrub vegetation; however, both are highly mobile and use associated habitats, especially sagebrush and grasslands (Blaisdell et al. 1984).