Successful control of invasive plants can have unexpected effects on native plants and wildland systems. Therefore, it is important for managers of invasive species to be concerned with ecological mechanisms and processes like invasion resistance, environmental heterogeneity, and succession that direct plant community dynamics. Augmentative restoration is a management approach for restoring desired species on wildlands dominated by invasive plants, where functioning ecological processes are maintained by selectively augmenting only those processes that are not operating sufficiently. The study was conducted within the Mission Valley, Montana, in an area where meadow vole disturbance provided site availability for colonization. In a split-plot design with four replications, eight factorial treatment combinations from three factors (shallow tilling, watering, and seeding) were applied to whole plots, and 2,4-D was applied to subplots. Cover and density of seeded species, spotted knapweed, and sulfur cinquefoil were sampled in July 2002 and 2003 to produce pretreatment and posttreatment data. Analysis of covariance was used to analyze cover and density data using pretreatment data as a baseline covariate. Data indicated that in areas with adequate site availability due to meadow vole disturbance, seeding and watering without tilling were required to increase seeded species. Spotted knapweed and sulfur cinquefoil decreased in response to 2,4-D. These data provided evidence that augmentative restoration may improve our ability to establish desired species on invasive plant–dominated wildlands.
Nomenclature: 2,4-D; spotted knapweed, Centaurea maculosa Lam.; sulfur cinquefoil, Potentilla recta L.
Additional index words: Environmental heterogeneity, invasive weeds, native plant establishment, successional management.
Abbreviations: ANCOVA, analysis of covariance.