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Flowering Rush: Invasion of the Columbia River System Video  Watch the Video Click the play arrow (on the left of the toolbar below the image) to view "Flowering Rush: Invasion of the Columbia River System." Approximate running time is 12 minutes. Video Abstract Flowering Rush (Butomus umbellatus) is an invasive Eurasian aquatic macrophtye with emerged and fully submerged forms that can dominate irrigation systems, wetlands, littoral zone of lakes, river edges and sloughs. Mapping in Flathead Lake Montana has delineated approximately 2,000 acres. It has passed through Kerr Dam and infested the Flathead and Clarks Fork Rivers 165 miles downriver into Lake Pend Oreille in north Idaho. There is also a large infestation near the headwaters of the southern reach of the Columbia River System in an irrigation system that spills into American Falls Reservoir on the Snake River. The large infestations at the headwaters of the Columbia River will continue to spread downstream and infest much of the main stem of the system. The Flathead Lake hydroelectric facility is operated to reach low pool in early spring, whereas an unregulated natural lake would reach low pool in late summer. This unnatural late summer through winter high pool with spring drawdown creates conditions that are favorable to establishment of flowering rush infestations and disadvantageous to native macrophytes evolved to a hydrologic cycle with a late summer low pool. It colonizes previously unvegetated portions of variable drawdown zones. These monotypic colonies in previously open water littoral zones are likely to induce cascading ecosystem and trophic effects on the Columbia River System. However, higher order impacts have not yet been studied. They are likely to include alteration of sediment transport and deposition, formation of new habitat favorable to introduced fish, and disadvantages to native trout and salmon. Video Credits Funded by a grant from: U.S Fish & Wildlife Service |
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