Kincaid’s lupine (Lupinus oreganus) and habitat monitoring at Fir Butte
One of the largest known extant populations of Kincaid’s lupine occurs at Fir Butte, located northwest of Eugene, Oregon. The overall habitat quality at the site is poor, with heavy
One of the largest known extant populations of Kincaid’s lupine occurs at Fir Butte, located northwest of Eugene, Oregon. The overall habitat quality at the site is poor, with heavy infestations of alien plants such as Rubus armeniacus (blackberry), Cytisus scoparius (Scotch broom), Centaurea pratensis (meadow knapweed), and Arrhenatherum elatius (tall oatgrass). These non-native plants are the primary threats to the lupine and butterfly, and their control is the main objective for management at this site.
This report summarizes the results of monitoring Kincaid’s lupine and the plant community at Fir Butte in 2011. Specifically, we (1) summarize the abundance of Kincaid’s lupine in 2011 and long term population trends, (2) briefly review the effectiveness of mowing and burning as management treatments, and (3) summarize the plant community composition and the utility of using quadrat vs. point-intercept sampling.
Kincaid’s lupine abundance has generally increased at Fir Butte since 1998. This is contributed to the efficacy of management treatments, which have suppressed invasive species spread.
All management treatments (mowing and burning) resulted in an increase in the cover of lupine and the number of inflorescences compared to their 2005 levels. The ecological burn had the greatest treatment effects. In addition, lupine in mowed plots attracted ovipositing female Fender’s blue butterflies, resulting in much higher egg numbers in mowed plots compared to unmanipulated plots
Using quadrats, we found that introduced perennial shrubs (blackberry) and introduced perennialgrasses was both dominant. Data from both methods showed that total cover of native species was less than one third that of introduced species. Point Intercept monitoring at Fir Butte had previously estimated that the most abundant species were introduced graminoids. It is our recommendation that point-intercept monitoring be the default community sampling method due to its better reliability between years.