Vulnerability Assessment of Wetland Habitats to Reed Canarygrass (Phalaris arundinacea) along Ross Lake, North Cascades National Park Service Complex
Project ID: P18AC01391
Federal Agency: National Park Service
Partner Institution: Washington State University
Fiscal Year: 2018
Initial Funding: $60,000
Total Funding: $60,000
Project Type: Technical Assistance
Project Disciplines: Biological
National Park: North Cascades National Park
Principal Investigator: Seefeldt, Steve
Agreement Technical Representative: Decker, Cheryl
Abstract: Ross Lake was created with the construction of Ross Dam (1937-1949) and the impoundment of the Skagit River. The lake forms the core of Ross Lake National Recreation Area and extends 23 miles south from the Canadian border. Water levels in the lake fluctuate by up to 80 ft as Seattle City Light manages the reservoir for recreation, power generation, and flood control creating a dynamic wet-dry cycle along the lakeshore that often seems to facilitate the spread of reed canarygrass over native wetland species. However, the recent and rapid spread of reed canarygrass within NOCA is not limited to the altered lake shore environment.
The vulnerability assessment will evaluate manipulated riparian areas along the lakeshore as well as “natural” wetlands located along Ross Lake tributaries. Hydroperiods in the wetlands located along the tributaries are predominantly natural, but the lakeshore is directly affected by reservoir operations. The vulnerability assessment will be conducted and evaluated in two areas regarding reed canarygrass: 1) vulnerability to seed or propagule dispersal, and 2) sensitivity to establishment. Vegetation cover, hydroperiod, soils, recreational and diurnal lake wind patterns are all believed to directly influence dispersal of reed canarygrass propagules. Hydroperiod is a significant determinant in the germination success of reed canarygrass seedlings or propagule, establishment of native species, and resilience of native communities to reed canarygrass invasion. The sensitivity of native aquatic organisms to reed canarygrass is also of interest, in particular the vulnerability of amphibian breeding habitats to reed canarygrass establishment.
Expected products from this project include: a vulnerability assessment of ROLA that identifies the sites most at risk of the spread of reed canarygrass, with recommendations for a strategy for the control of reed canarygrass within ROLA and throughout NOCA. A database of the attributes used to determine the assessment will also be provided.