Prairies are one of the rarest ecosystems in Washington. Less than ten percent of historic prairie in the South Sound region remains today, and an even smaller portion is dominated by native species. These ecosystems are a remnant of ice age glaciers, which left behind large swaths of gravelly, well-drained soils after their retreat.
Prior to settlement by Europeans, prairie habitat covered an estimated 180,000 acres of Washington. These open, comparatively flat, non-forested areas were conducive to development for obvious reasons, and accordingly disappeared over the 19th and 20th centuries as populations and settlement grew.
The ecosystem naturally relies on periodic disturbance. Naturally occurring wildfire, as well as those historically set by indigenous peoples, have kept prairies open and beat back the encroachment of trees and woody plants. Fire suppression and the spread of of non-native plants have contributed to the further disappearance of this special landscape.
Notable Species Found in Washington's Prairies
The widespread loss of Pacific Northwest prairies has meant trouble for many native species that call this ecosystem home. Some of these species are currently listed under the Endangered Species Act. Others, thanks to intensive recovery efforts, are bouncing back. A few of these notable species include:
- Golden paintbrush (Threatened, proposed for delisting)
- Island marble butterfly (Endangered)
- Kincaid's lupine (Threatened)
- Mazama pocket gopher (Threatened)
- Nelson's checker-mallow (Threatened, proposed for delisting)
- Oregon vesper sparrow (Status under review)
- Streaked horned lark (Threatened)
- Taylor's checkerspot butterfly (Endangered)
The Disappearance of South Sound Prairies
These two maps show the extent of historic prairie in the South Sound before development in the 19th century (left), and what remains today (right)
- JBLM Sentinel Landscape Program
Joint Base Lewis-McChord (JBLM) is the largest military installation on the west coast of the United States while also hosting 90% of the remaining prairie habitat in the South Puget Sound. The prairie ecosystem has thrived on JBLM where development is minimal and periodic fires caused by prescribed burning and military training activities have maintained healthy vegetation. JBLM Sentinel Landscape partners have worked together to enact conservation measures to strengthen military readiness through the recovery of threatened and endangered species.
- Bringing Back Native Prairie at a Washington Tree Farm
Our Partners for Fish & Wildlife Program is working to restore this Christmas tree farm to native prairie, piece by piece.
- A Family Dairy Farm Helps Recover a Threatened Flower
The 320-acre Mallonee dairy farm in southwest Washington has been in the family for four generations. Now, these private partners are aiding in the recovery of the threatened Kincaid's lupine.
The Golden Paintbrush Recovery Story
A few decades ago, this small but vibrant flowering plant was a rare sight within Washington and Oregon’s dwindling prairie habitats. Thanks to intensive efforts by many partners, the plant has rebounded.
Informational and Educational Resources
- Puget Prairie Plants
Species profiles of the flora of Salish Sea prairies from Evergreen State College
- South Sound Prairies - Western Washington's Grasslands
Video about the ecosystem and its conservation by the Center for Natural Lands Management
- Guide to the Mima Mounds (PDF)
An educational booklet from the Washington Department of Natural Resources about Mima Mounds Natural Area Preserve in Thurston County