- We report results from a field experiment evaluating the effectiveness of mowing, mowing
and herbicides, and burning on woody plants, key native and non-native grasses and forbs,
and the Fender’s blue butterfly. The goal was to find a technique that controlled woody
pest plants without harming native species or promoting non-native species.
Three years after the initial manipulations, all treatments significantly reduced woody
plant cover. Mowing promoted the group of measured native grasses without promoting
non-native species. In contrast, burning had mixed effects on herbaceous species,
promoting growth for some species and decreasing growth for others. Each treatment,
particularly mowing, caused local increases in numbers of Fender’s blue butterfly egg
masses, probably because lupines invigorated by treatments attracted ovipositing females.
Although prescribed burning seemed to kill larvae, treated areas still accumulated more
eggs masses than in controls.
Three years after the start of manipulations, mowing was the most effective overall
treatment for controlling woody plants, increasing native species abundance without
promoting non-native species, and increasing Fender’s blue butterfly numbers. We
recommend mowing for restoring similar habitats. Prescribed burning would also be an
effective choice for habitat restoration.