January 16, 2015

Restoration of Willamette Valley upland prairies at Fern Ridge Lake

Erin C. Gray and Matt A. Bahm | 2015

Fern Ridge Research Natural Area (RNA) is a cluster of remnant prairie sites within the southern Willamette Valley, managed by the Bureau of Land Management Eugene District. The Fern Ridge master plan

Fern Ridge Research Natural Area (RNA) is a cluster of remnant prairie sites within the southern Willamette Valley, managed by the Bureau of Land Management Eugene District. The Fern Ridge master plan provides these sites with wildlife habitat or environmentally sensitive land use designations. The current rare species management plan and Biological Opinion place primary emphasis on activities to benefit listed species; all sites except one are designated critical habitat for Fender’s blue butterfly, L. oreganus, or both.

The sites in this project have been mowed since the 1970’s, which has allowed native plants to persist despite the presence of aggressive invasive plants, such as Ahrrenatherum elatius  (tall oat grass), Cytisus scoparius (Scotch broom), and Rubus spp. (blackberries). Fender’s blue butterfly and Lupinus were first identified in 1998 and have since been the primary targets for management. The goal of this project is to build upon these efforts to restore a matrix of native prairie grasses with moderate native forb diversity through a treatment matrix, followed by treatment specific to  each plot’s emerging plant community. We will also apply several small-scale treatments that have the potential to increase restoration success, but are either relatively new restoration techniques or are prohibitively expensive to apply on a large scale. These treatments will include solarization, pre-emergent herbicides, pre-emergent herbicides combined with carbon banding, and sucrose addition.