Invasive species are non-native, or out of place, species that causes ecological or economic harm within the environment. Plants that are invasive can outcompete native species for light, water, space, and soil nutrients. Ultimately, native plant species are displaced, and the habitat becomes unfavorable for native birds and pollinators as a monoculture of one or two plant species develops. Often, invasive species hold reduced economic value in terms of forage for livestock. By taking away resources from native plants they reduce the overall economic and diversity potential of the landscape. Invasive species include state-listed noxious weeds but also consist of non-native grasses like cheatgrass, Kentucky bluegrass and smooth brome, and native and non-native woody species like eastern red cedar, buckthorn, honey locusts, Siberian or Chinese elms, dogwood, and sumac.  

Invasive species can be promoted or hindered through management. There are various tools utilized at different times of the year to reduce the competition from invasive species. These tools include grazing, mechanical harvest, fire, herbicide, and rest. These grassland management tools can be helpful or harmful in increasing or reducing the incidence of invasive species, depending on how and when they are implemented. Grazing, for example, can promote invasive grasses if practiced in an incompatible way. However, grazing is also a very powerful tool for reducing those same invasive grasses if practiced when those invasive plants are vulnerable.