For more information on species & ecosystem science:

Wildlife Science
360-902-2515
wildthing@dfw.wa.gov

Fish Science
360-902-2700
fishpgm@dfw.wa.gov

Habitat Science
360-902-2534
habitatprogram@dfw.wa.gov

 

Shrubsteppe Ecology

 
 

Big sagebrush-bunchgrass community, Horse Heaven Hills near Prosser.

   
 
 

Sage sparrows are one of several sagebrush-obligate birds in Washington.

   
  Click on map to enlarge
Click on map to enlarge
 

Current (bottom) and historic (top) extents of shrubtsteppe/steppe habitats in eastern Washington. Green=forest; darkbrown=shrubsteppe/steppe; tan=cropland.

   
 
 

Sagebrush-steppe and rimrock along the Columbia River near Vantage.

   
 
 

Wheat fields now dominate the historic grasslands of the Palouse Prairie in southeast Washington.

   

Shrubsteppe communities form the iconic, western landscape of open sagebrush plains, rimrock, and tumbleweeds. Described as vegetation communities consisting of one or more layers of perennial grass with a discontinuous overstory layer of shrubs, shrubsteppe historically dominated the landscape in eastern Washington. Some of the many species of wildlife that inhabit shrubsteppe can only be found in these semi-arid communities. Greater sage-grouse, sage sparrows, sage thrashers, and pygmy rabbits are among an elite group of species that depend on sagebrush and are termed “sagebrush obligates”. A host of other birds, mammals, reptiles, and insects are found primarily in sagebrush-steppe or other shrubsteppe communities.

Today, less than 50% of Washington’s historic shrubsteppe remains (Fig. 1), and much of it is degraded, fragmented, and/or isolated from other similar habitats. Conversion to cropland has resulted in the greatest loss of shrubsteppe in Washington, leading to a fragmented landscape and a differentially high loss of deep-soil communities. Across the Intermountain West, shrubsteppe communities have been lost or degraded by conversion to cropland, extensive energy extraction, and alteration of the vegetation through over-grazing, invasion by exotic plants and changes in fire frequency.

Anthropogenic changes in these unique habitats have caused severe declines in species like the greater sage-grouse and have led to the extirpation of the pygmy rabbit in Washington. Other shrubsteppe-associated species that are likely on the decline include the Washington ground squirrel, Brewer’s sparrow, and burrowing owl. Conversion of shrubsteppe to cropland and other uses is responsible for much of the observed declines in native species; however, the pattern of habitat loss and how remaining habitat is configured on the landscape likely plays a significant role in determining use by wildlife.

Since the 1980s, WDFW scientists have been studying how changes in the landscape in eastern Washington affect shrubsteppe-associated wildlife. Our research has focused on providing information that can be used by land managers to minimize effects of development on shrubsteppe-associated wildlife.

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