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Riparian Plants of the Bear Creek Watershed. December 2009.
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Riparian Plants of the Bear Creek Watershed December 2009
The Bear Creek Watershed Virtual Tours were created with funds provided by the Bear Creek Watershed Education Partners through a grant from the Oregon Watershed Enhancement Board with additional funding from Oregon Trout’s Healthy Waters Institute. THANKS TO: Terri Eubanks Brandon Goldman Tom Collette
Riparian Habitats Riparian areas are the strip of vegetation growing alongside freshwater. This habitat is different from habitats farther from the stream (called uplands) and are closely affected by the stream’s presence. The soils in riparian areas contain more moisture for longer periods of time and changes in the stream can affect the riparian habitat. Like other habitats, riparian areas are made up of different plant species such as trees, brush or shrub species, and non-woody plants like grasses and herbs. Photo by Brandon Goldman
Trees Common trees in the riparian area include: • Black Cottonwood • Willow species • Oregon Ash • Alder • Big-leaf maple • Vine Maple Bear Cr. at Lazy Cr. confluence
Black Cottonwood is a very common and visible tall tree in the riparian areas at the lower elevations of the Bear Creek watershed. Photos: Tom Collett
Photos: Tom Collett There are many different species of willows that grow in our watershed and all over the world. In the Bear Creek watershed, willows can look like a shrub or a small tree. How do these two species of willow look different?
Oregon Ash is a deciduous tree with leaflets in groups of 5-7 Oregon Ash seeds What is a deciduous tree? One that loses its leaves in winter. Most broad leaf trees are deciduous.
Alder have long drooping catkin flowers in spring and serrated leaf edges. The tree produces what look like tiny “pine cones” which contain the seeds.
Maples Big-leaf maple and Vine maple are the two common native maple species in Bear Creek riparian areas. And guess what, Big-leaf maple has big leaves.
Maple seeds are familiar as the “helicopter seeds” that spin as they fall and blow from maple trees. How do these “wings” help the maple tree? Big-leaf maple seeds
Riparian tree species are able to withstand the changing stream conditions. From raging floodwaters to dry summers, riparian trees survive the dynamic system. Photo by Brandon Goldman
Riparian plants are important They protect stream banks by holding soil. They shade stream waters, keeping streams cool and good habitat for native fish and animals. They filter pollutants running into the stream. Healthy riparian areas improve stream flow by regulating groundwater discharge. Healthy riparian areas slow flood flows. Healthy riparian areas are good habitat. What would our streams look like without riparian areas? How would they function?
Invasive Plants Some plants are not native to the Bear Creek area, meaning those plants did not live here before western settlers arrived and most were introduced recently. Himalayan blackberry Scotch Broom
Invasive plants are a problem. Plants that are not native can take over habitats. Have you ever seen large areas with only blackberries growing? Invasive plants crowd out native plants and animals so the natives do not have a place to live. What did the riparian areas of Bear Creek look like before blackberries took over? Purple Loosestrife
Puncture Vine is a low growing non-native ground cover that produces very sharp spiny seeds in a unique shape which gives the plant its other name of “Goathead”. This plant is commonly seen along the Bear Creek Greenway path and other disturbed areas. Bike riders hate Goathead. Why?
Try to keep weeds from moving to new places by not letting their seeds be hitchhikers on your pets, clothing, or vehicles.
Riparian habitats in the Bear Creek watershed are a valuable resource to enjoy and protect. Ashland Creek in Lithia Park Photo by Brandon Goldman
Note to user: • Objective of presentation: brief introduction to native and invasive plants found in Bear Creek watershed riparian areas. • Most appropriate for: Ages 6 and up • How to integrate this presentation into other activities: • Take a walk to a nearby wet area, stream, or irrigation canal and see if any of these plants are observed. Record data on presence/absence, ratio of native to non-native species. Compare different riparian areas. • Bring in plant samples, identify, draw , categorize, or describe plant characteristics and habitats. Discuss plant adaptations.