Knife River Indian Villages National Historic Site - Nonnative Species

For several years the park has undergone an exotic plant control program, which includes the use of herbicides on species such as leafy spurge and Canada Thistle. Due to the efforts of the staff, many of these encroaching flora have been set back to manageable zones. Leafy Spurge for example, has been treated with traditional herbicides, biocontrol and even prescribed fire. Biocontrol techniques using a species of Flea beetles has shown great promise in the past and is at a stage within the park where future control plot should start expanding at a tremendous rate. Although the park is making good advances toward controlling the exotic plants in the park, it is realized that due to the proximity of the two rivers, it is unlikely that the total control of some exotic plants will ever occur.

Smooth brome grass is perhaps the largest problem for our staff. The ability of the grass to choke out all other native competition has been a constant dilemma at the park. Any areas in the forest that have an open canopy are encroached by smooth brome. This encroachment prevents forest and grassland successions from occurring. Different strategies are being used at this time to combat this problem. Primarily prescribed burns have been targeted during the periods when the plants are most susceptible.