Plants and Wildlife

Cutthroat trout spawn and live their lives within the Greater Yamhill Watershed’s streams, including Chehalem Creek. Coho salmon, winter steelhead, and lamprey are present in the watershed. These species are anadromous—fish that spend their adult life at sea and breed in freshwater. Another anadromous fish, Chinook salmon, do not spawn in the watershed, but young salmon from Cascade Range spawning streams will move from the Willamette River into the lower Yamhill River during the higher winter and early spring flows as they make their slow journey to the ocean. Coho salmon, which are weaker swimmers than Chinook salmon and could not ascend Willamette Falls, were not historically present in the watershed. With the addition of a fish ladder at the falls, Coho are now accessing spawning areas in the Yamhill River and other Willamette River tributaries and their populations are growing.

As a result of habitat modifications, historical overfishing, and other factors, Willamette River Basin Chinook salmon and steelhead trout populations have declined to alarming levels, and the larger reproductive units they belong to—the Upper Willamette River Chinook evolutionarily significant unit (ESU) and the Upper Willamette River steelhead distinct population segment (DPS)—are listed as threatened under the ESA.

The increasingly rare native upland habitats are home to important plant and wildlife species. One example is Kincaid's lupine. This lupine, which grows in native prairies that have been virtually eliminated from the Willamette Valley as a result of conversion to agriculture, urbanization, and other development, is threatened in the wild. Fender's blue butterfly, which is protected under the federal Endangered Species Act (ESA), needs Kincaid’s lupine to survive. The butterfly’s larvae eat the plant’s leaves during the fall then crawl down the stem and hide among the roots during the mild winters. In spring, the larvae re-emerge and eat more leaves and then form cocoons.