South Sound Strategy: Prairie and Oak Woodlands

Focus Area: Prairie and Oak Woodlands

Attribute(s) Common to this Focus Area

  • Native Prairie and Oak Woodlands


South Sound is unique in the Puget Sound Region as the historic and only remaining location for native prairies and oak woodlands. South Sound native prairies support an array of plant and animal species, including several endangered species: Taylor’s Checkerspot butterfly, Mardon skipper, streaked horned lark, Western gray squirrel, and Mazama pocket gopher. According to the Center for Natural Lands Management (CNLM), 150,000 acres of prairie landscape and habitat has been reduced by 90%, with only 3% of that remaining as pristine prairie. Oak woodlands are dominated by Oregon white oak, the only oak species native to Washington, and contribute to the South Sound’s rich biological diversity by providing feeding, breeding, resting and sheltering habitat for more than 200 species of birds, mammals, reptiles, and amphibians.


According to the Washington DNR Natural Heritage Program, only about 16,000 acres of native prairie habitat remain in the South Sound. Approximately 14,300 acres (90%) occur on lands protected and managed by federal and state agencies and non-governmental organizations. Prairie habitats are generally concentrated in a few locations in the lower and middle watersheds of the Deschutes and Nisqually rivers, with the majority present inside the Joint Base Lewis-McChord (JBLM). The Chambers-Clover watershed contains nearly 2,000 acres of prairie and 97% is in some type of protected status. The greatest amount occurs within the Nisqually watershed (11,606 acres) with 95% in protected status

Key Pressures

  • Conversion of land from prairie or oak woodland to agriculture or urban and suburban development
  • Lack of natural disturbance
  • Spread of invasive species and weeds
  • Overgrazing
  • Habitat fragmentation


AHSS does not have numerical local targets for this focus area or its attributes at this time. Coordinated and ongoing efforts will maintain 100% of all remaining prairie and oak woodlands (as classified by WDNR Heritage Program data), place lands in protected status, and work to restore historic extant areas as identified and prioritized in current management plans.

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