The South Puget Sound Glacial Outwash Prairie Ecosystem

Think about a flat forested area or farm field around here, and allow your vision to lapse into time machine mode to meld back to 13,000 years ago, during the last ice age. This entire area was covered by glaciers. Olympia was the borderline of the glacier’s reach in the Pac NW. The ice scoured the land and captured sand and gravel, rocks and boulders within the ice. When the ice melted, sand and gravel “outwashed”, making our area unique geologically.

After the melting and receding of the glaciers, the Pac NW was much warmer and drier. With the well-drained glacial outwash soils and intermittent summer wildfires, the landscaped mimicked areas much further south. Plants that had advantages in, or needed warmer dry climates with fires spread and thrived. Many of these southern plants were wildflowers that had starchy roots and oaks that provided acorns, and were very important to the First Peoples of this area. Important also were berry bushes that sprouted after a fire, the new succulent grasses and forbs that attract large herbivores.

Then, the climate started to cool and 4,500 years ago the climate was much as it is now. Can you see with your eyes the forest taking over places that no longer had a unique adaptive edge because of the wildfires? Can you see the places with glacial outwash soil becoming biodiversity islands? Forests are beautiful and important, but yield relatively little food. Have you ever tried to chow down on sword fern or cedar?

Intentional fires became very important. The people who lived in these areas—most recently Southern Lushootseed-speaking peoples—burned prairies and prevented forests from regenerating to protect these important food-scapes. Repeated wildflower bulb harvesting aerated the soils, making these prairies more productive. Periodic fires created a mosaic of successional biodiversity.

Can you guess what happened when white settlers came? Well, to start off, these beautiful camas prairies were so blue and quivering in the breeze that from a distance Lewis and Clark weren’t sure if they were fields or lakes. Then upon close examination these prairies seemed so pristine that it was inconceivable to Captain George Vancouver and others that these ecosystems were tended in any way that achieved similar food-producing functions as the traditional mono-crop European style agriculture characterized by straight lines and rows. Landscape tending, in a middle ground between passive “wilderness” and ecologically-devastating agriculture was invisible to their mind-set, and continues to not be an option in our own. These areas were coveted for development and farmland because they were low-elevation, near valley bottoms and rivers, and relatively tree and stump free. Traditional burnings were discouraged and prevented, and native groups all over the Pacific Northwest were confined to reservations where they were coerced into and force-fed European agricultural methods. As their former harvesting grounds were not recognized as being cultivated, only parts of their fishing rights were recognized beyond their reservation borders.

In the absence of wildfires or traditional tending practices, the prairies became slowly invaded by (local but invasive) Douglas-fir and other forest species. Prairie soils were tilled, new forests became tree farms, scotch broom invaded, and prairies engulfed by suburbia to this day.

However a change has started to take place in our area. Remnant prairies such as the Mima Mounds, and the Glacial Heritage Area have been preserved from development, and restoration to protect endangered plants and animals has begun. Effective restoration of these areas has been slow to start, especially as the caretakers for these areas were displaced and traditional ways of keeping the land such as harvesting and burning are rarely implemented.

I hold hope for stewardly practices of landscape-tending to be recognized, remembered, and re-enlivened. However; studying these areas and restoring them in what ways are most feasible on a large scale is the next best thing as we ascend the steep learning curve of knowledge lost.

If you want to help prairie restoration, you can volunteer for The Nature Conservancy every Tuesday anytime from 9am until 3pm, at various locations at prairie areas just south of Olympia or at their prairie plant nursery in Littlerock, WA. Daeg Byrne with TNC is a contact for these projects, and is available at 360-480-3000 or dbyrne@tnc.org. This coming Tuesday volunteers will be planting native grass starts in a large area that was intentionally burned in Glacial Heritage Reserve. Daeg has noted that although year to year changes are hard to see, prairie restoration efforts over the last few years have made a big difference: plantings are thriving and unique species are returning.

For more information about stewardship in the prairies and other whole landscapes, see also Keeping It Living: Traditions Of Plant Use And Cultivation On The Northwest Coast Of North America by Douglas Deur and Nancy J. Turner

Laura Donohue
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