Biological Invasions of Riparian Ecosystems: Technical Support for Riparian Conservation Planning on the Colorado and Green Rivers in Utah

Research Project: 

RB00CKY.7.0

Project Manager: 

Pat Shafroth
Colorado River after a high flow experiment
Colorado River after a high flow experiment

The National Park Service (NPS), Bureau of Land Management (BLM), and The Nature Conservancy (TNC) are conducting coordinated conservation actions along the Green and Colorado River corridors in Utah to enhance resource conditions and related societal values associated with these iconic riverine ecosystems. Since the late 19th century, riverine ecosystems throughout much of western North America have been altered through the introduction of nonnative plant and fish species, water withdrawals, flow regulation by dams, and many other human activities. Riparian vegetation in the project area currently is undergoing rapid change as extensive stands of nonnative tamarisk (Tamarix spp., the dominant woody plant in the river corridor) are being affected by expanding populations of the tamarisk leaf beetle (Diorhabda elongata). This beetle was first released in this region in 2005 to control the spread of tamarisk.

Rapid changes in tamarisk populations, associated changes in geomorphic conditions and plant community characteristics (including an influx of additional exotic plant species), and increasing uncertainty about effects of climate change and societal water demands on future flow regimes have resulted in heightened concern about how to most effectively protect or restore resource values along the Colorado River corridor. Collectively, NPS, TNC, and BLM have identified a need for science-based technical support in planning, coordinating, and implementing prioritized conservation actions that will achieve maximum benefits to riverine resources and societal values with limited financial and human resources. FORT has been selected to provide this technical support because of its recognized scientific expertise and credibility in the ecology of riverine ecosystems. Currently their work applies to 146 miles of the Colorado River floodplain, extending from the Utah/Colorado border downstream to the upper limit of Lake Powell in Utah. Future work may extend to the Green River in Canyonlands National Park.