- We report first-year results from two field experiments evaluating the effectiveness of
various techniques for the control of pest plants in Fender's blue butterfly habitat. In the
woody-plant study, we monitored the effects of mowing, mowing and herbicides, and burning
on woody plants and key native and non-native grasses and forbs. All treatments reduced
woody plant cover, and no treatment significantly harmed populations of important native
species. One year after manipulations, burning was the most effective overall treatment.
In the tall-oatgrass study, we monitored the effects of different mowing regimes on
groups of native and non-native grasses and forbs. No regime caused a statistically significant
decline in tall oatgrass, although mowing in early summer or late fall were particularly
promising techniques at reducing non-native cover without diminishing native species.
Removing cut material greatly reduced the effectiveness of mowing.
Burning in the woody-plant control study and certain mowing regimes in the tall-oatgrass
control study performed well. As for the other treatments, nothing in these studies
calls for halting the use of the pest-plant control techniques evaluated, except for the removal
of cut material. On the other, the effectiveness of the techniques is still unclear, especially in
promoting native species. Additional years of manipulations and monitoring should help
resolve these issues.