Washington State Natural Regions

Beyond the Treeline: Beyond the Forested Ecosystems: Prairies, Alpine & Drylands

WA Dept. of Natural Resources 1998

West-side Prairies & Woodlands Oak Woodland & Prairie Ecosystems West-side Oak Woodland & Prairie Ecosystems in Grey San Juan Island Prairies 1. South Puget Sound prairies & oak woodlands 2. Island / Peninsula coastal prairies & woodlands Olympic Peninsula 3. Rocky balds Prairies

South Puget Prairies

WA GAP Analysis project 1996

Oak Woodland & Prairie Ecosystems San Juan West-side Island South Puget Sound Prairie Ecosystems Oak Woodland & Prairie Prairies Ecosystems in Grey Grasslands dominated by Olympic • Grasses Peninsula Herbs Prairies • • Bracken fern South • Mosses & lichens Puget Prairies With scattered shrubs

Camas (Camassia quamash) WA GAP Analysis project 1996

•1 South Puget Sound Prairie Ecosystems South Puget Sound Prairie Ecosystems Mounded prairie Some of these are “mounded” prairies

Mima Mounds Research Natural Area

South Puget Sound Prairie Ecosystems South Puget Sound Prairie Ecosystems

Scattered shrubs

Lichen mats in the prairie

Serviceberry

Cascara

South Puget Sound Prairie Ecosystems South Puget Sound Prairie Ecosystems

As unique ecosystems they provide habitat for unique plants As unique ecosystems they provide habitat for unique critters

Camas (Camassia quamash) Mazama Pocket Gopher

Golden paintbrush Many unique species of butterflies (Castilleja levisecta) (this is an Anise Swallowtail)

Photos from Dunn & Ewing (1997)

•2 South Puget Sound Prairie Ecosystems

Fire is an important & natural part of ecosystems Garry Oak Woodlands

• Often associated with prairies • Riparian corridors in prairies • Extensive in Islands & BC

Quercus garryana Photo from Dunn & Ewing 1997

Garry Oak Woodlands Oak Woodland & Prairie Ecosystems: Human Impacts Current prairie cover is about % of its historical extent in South Puget Sound Important Habitat Causes of Prairie Loss Hall (1995) Urban development %

Forest invasion % Tacoma

Agriculture %

Olympia

Mazama pocket gopher Mardon skipper & other Streaked horned lark Western gray squirrel butterflies Crawford & Hall 1997

South Sound Oak Woodland & Prairie Ecosystems: South Sound Oak Woodland & Prairie Ecosystems: Protected Areas Protected Areas

•3 Oak Woodland & Prairie Ecosystems: Human Impacts Fort Lewis & McChord Air Base: Protected Areas > 75,000 acres of training grounds Invasive Species are another threat

Tacoma

86,000 acre reservation Fort Lewis Olympia

Scot’s Broom (Cytisus scoparius) Fort Lewis

Oak Woodland & Prairie Ecosystems: Human Impacts Oak Woodland & Prairie Ecosystems

Control of Scot’s Broom These prairies & woodlands exist within the same climate as the surrounding sea of evergreen forest. WHY?

A central question: What prevents the forest Burning from existing here? Pulling

What Restricts Forest Cover? What Restricts Forest Cover? PLANT INVESTMENTS Wood becomes a luxury in droughty conditions

Sugar Sugar

Herbaceous Woody Plant Herbaceous Woody Plant Plant Plant

leaves wood roots leaves roots leaves wood roots leaves roots

NOW IMAGINE DROUGHT CONDITIONS This suggests herbaceous plants will do better in drier locations

Which can better support its leaves with drought? Are these prairies & woodlands in drier locations?

•4 Oak Woodland & Prairie Ecosystems Development of Puget Prairies

To understand if our west-side prairies are in dry sites 18,000 YBP we must understand the history of the ground beneath !

15,000 YBP Glacier recedes

12-15,000 YBP

Coarse, droughty substrate

Oak Woodland & Prairie Ecosystems Oak Woodland & Prairie Ecosystems Development of Puget Prairies Development of Puget Prairies

10,000 YBP 10 - 12,000 YBP Grasses & Soil holds more water forbs & nutrients establish Trees & shrubs begin to establish

7 - 10,000 YBP 9 - 10,000 YBP Organic matter Climate shift: added; HYPSITHERMAL Soil building Too warm & dry for trees; prairies remain

Oak Woodland & Prairie Ecosystems Oak Woodland & Prairie Ecosystems Development of Puget Prairies Development of Puget Prairies

5 - 7,000 YBP Climate cools & 5 - 7,000 YBP Climate cools & becomes more wet becomes more wet Trees & shrubs begin Trees & shrubs begin to establish again to establish again Humans arrive Humans arrive

200 - 7,000 YBP 200 - 7,000 YBP FIRE We would expect: Native Americans Soil OM builds use fire to keep trees rapidly & shrubs out – Forest establishes maintaining prairie

•5 Oak Woodland & Prairie Ecosystems West-side Prairies & Woodlands Development of Puget Prairies

Post European settlement Fire suppression allows forest succession to 1. South Puget Sound prairies & oak woodlands proceed 2. Island / Peninsula coastal prairies & woodlands

How do we maintain these unique ecosystems in the face of natural succession to forests?

Oak Woodland & Prairie Ecosystems Oak Woodland & Prairie Ecosystems Prairies in San Juan Islands, NE Olympic Peninsula & Coastal Bluffs Rainshadow of the San Juans & NE Olympic Peninsula Just a little different

Inches of • Coarse, dry post-glacial soils annual • Rainshadow – low precipitation precipitation

Oak Woodland & Prairie Ecosystems West-side Prairies & Woodlands Prairies in San Juan Islands, NE Olympic Peninsula & Coastal Bluffs Just a little different

• Coarse, dry post-glacial soils 1. South Puget Sound prairies & oak woodlands • Rainshadow – low precipitation 2. Island / Peninsula coastal prairies & woodlands • Wind exposed 3. Rocky balds • Unusual soil chemistry

•6 Rocky Balds: another west-side ecosystem not West-side Prairies & Woodlands dominated by trees

South Puget Sound prairies & oak woodlands Island / Peninsula Windswept resistant bedrock coastal prairies & woodlands outcrops Rocky balds

What is the common reason all of these ecosystems exist? More common on San Juan Islands How is that different from the factors that tend to control Unique, rare species ecosystem existence for our more extensive ecosystems? Lord Hill, Snohomish County

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