When ODOT can’t avoid having an impact on the habitat around roads and bridges, it mitigates for the work by establishing and maintaining land elsewhere to benefit threatened and endangered species, with expert help from the U.S. and Oregon Fish and Wildlife Services.
To mitigate for its construction, the bridge program purchased 20 acres west of Corvallis that will help conserve the endangered Fender’s blue butterfly, found only in the Willamette Valley. ODOT’s partner, the Oregon Department of Fish and Wildlife, had already begun establishing a network of habitat patches large enough to support a self-sustaining population of the endangered butterfly.
Cattle inadvertently trample the threatened Kincaid’s lupine that is the primary food source for the butterflies’ larvae. To protect the acreage, bridge program specialty contractor TB Irrigation installed 4,400 feet of wildlife-friendly fencing around the plot. It allows rabbits, raccoons and other wildlife in, while preventing cattle from grazing on or trampling the butterflies’ lupine lunch.
The butterflies will likely recolonize the lupine patch on their own in due time. Long-term maintenance of the site will be handled by ODOT’s Geo-environmental section.