Kincaid’s Lupine (Lupinus oreganus) and Habitat Monitoring at Fir Butte

EXECUTIVE SUMMARY
This report documents work conducted on Kincaid’s lupine (Lupinus oreganus), a threatened species listed by the Oregon Department of Agriculture and the U.S. Fish and Wildlife Service, and the surrounding plant community at Fir Butte. Kincaid’s lupine serves as the primary larval host plant for the endangered Fender’s blue butterfly (Icaricia icarioides fenderi); both species are endemic to western Oregon prairies. Fir Butte is an 18 acre prairie remnant owned by the Eugene District BLM and currently managed primarily for Kincaid’s lupine and Fender’s blue butterfly.

In 2017 we monitored Kincaid’s lupine and the plant community at Fir Butte.
• Blackberry cover was reduced in the initial research experiment, but cover remains relatively high.
• Mowing can be used to maintain current blackberry cover values, but herbicides and/or grubbing will likely be required to further reduce blackberry.
• Lupine cover rebounded over the past two sampling years, with cover measuring 2,469 m2 in 2017, which was the second highest cover value measured throughout the course of this study.
• Introduced perennial grasses were the dominant components of the plant community.
• Continued efforts to decrease these populations and increase native plant diversity are necessary.
• High litter cover observed in recent years could limit native species. There is little bare ground available for seed germination.