Author
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Carpinelli, Michael |
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Submitted to: Plant Conservation Alliance: Weeds Gone Wild
Publication Type: Other Publication Acceptance Date: 4/22/2003 Publication Date: 4/23/2003 Citation: CARPINELLI, M.F. SPOTTED KNAPWEED FACT SHEET. AVAILABLE FROM: HTTP://WWW.NPS.GOV/PLANTS/ALIEN/FACT/CEBIL.HTM WEEDS GONE WILD: ALIEN PLANT INVADERS OF NATURAL AREAS. PLANT CONSERVATION ALLIANCE, BUREAU OF LAND MANAGEMENT [2003] Interpretive Summary: Spotted knapweed, a native of Eurasia, is a biennial or short-lived perennial member of the Sunflower (Asteraceae) family. It infests a variety of natural and semi-natural habitats where it out competes native plant species, reduces native plant and animal biodiversity, and decreases forage production for livestock and wildlife. Spotted knapweed is a widely distributed species throughout North America and has been designated as a noxious weed in fifteen states. Spotted knapweed prefers well-drained, light-textured soils that receive summer rainfall, including open forests dominated by Ponderosa pine and Douglas fir, and prairie habitats dominated by Idaho fescue and bluebunch wheatgrass. Disturbance allows for rapid establishment and spread; however, spotted knapweed is capable of invading well-managed rangelands. A variety of mechanical, biological, cultural, and herbicidal control methods are used to manage spotted knapweed. Technical Abstract: Spotted knapweed, a native of Eurasia, is a biennial or short-lived perennial member of the Sunflower (Asteraceae) family. It infests a variety of natural and semi-natural habitats including barrens, fields, forests, prairies, meadows, pastures, and rangelands. It out competes native plant species, reduces native plant and animal biodiversity, and decreases forage production for livestock and wildlife. Spotted knapweed may degrade soil and water resources by increasing erosion, surface runoff, and stream sedimentation. Spotted knapweed is a widely distributed species reported to occur throughout Canada and in every state in the U.S. except Alaska, Georgia, Mississippi, Oklahoma, and Texas. It has been designated as a noxious weed in Arizona, California, Colorado, Idaho, Minnesota, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming. Spotted knapweed is found at elevations up to and over 10,000 feet and in precipitation zones receiving 8 to 80 inches of rain annually. Spotted knapweed prefers well-drained, light-textured soils that receive summer rainfall, including open forests dominated by ponderosa pine and Douglas fir, and prairie habitats dominated by Idaho fescue and bluebunch wheatgrass. Disturbance allows for rapid establishment and spread; however, spotted knapweed is capable of invading well-managed rangelands. Spotted knapweed does not compete well with vigorously growing grass in moist areas. In seasonally dry areas, spotted knapweed's taproot allows it to access water from deep in the soil, beyond the reach of more shallowly rooted species. A variety of mechanical, biological, cultural, and herbicidal control methods are used to manage spotted knapweed. |
