Effects of fire, mowing, and mowing with herbicide on native prairie of Baskett Butte, Baskett Slough National Wildlife Refuge

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.