Native grassland communities may resist invasion by introduced plants through allelopathy, where they release chemicals that affect the growth of other plants. In a study, researchers tested if native plants affect the invasibility of introduced species. They found that the presence of native plants reduced the survival and growth of introduced plants, but adding activated carbon to the soil neutralized this effect. Both invasive and non-invasive introduced plants showed similar tolerance to the allelopathic effects of native plants. This suggests that native plant communities can resist invasion by introduced plants through allelopathy, but the invasiveness of introduced plants is not related to their tolerance to these effects.