Allelopathic Effects of S. canadensis on the Germination of Native Prairie Plants

Solidago canadensis has become a aggressive species of North American prairie forb throughout the world and within restored prairies throughout North America, causing the loss of biodiversity within those ecosystems. While reproductive methods of wind dispersed seeds and clonal expansion through rhizomes has helped S. canadensis colonize and spread through these ecosystems, S. canadensis also releases allelopathic chemicals which may inhibit the germination and growth of competing species. What was unknown is if these same allelopathic chemicals which give S. canadensis an edge within foreign ecosystems might also explain why S. canadensis is so prolific in restored North American prairies. To test the allelopathic effects of S. canadensis on other North American prairie plants, seeds representing three main plant forms; grasses, forbs, and legumes; were germinated in the presence of extracts made from S. canadensis leaves. The allelopathic chemicals used by S. canadensis appear to target one life form; grasses; over the others. Given that S. canadensis is more likely to compete with grasses than any individual specific species of forb or legume, significant differences among life forms should result in a strong benefit to the species. The degree of response among grass species did vary dramatically, with strong response on some species and no response in others. This specificity suggest that when choosing grass species for a restored prairie, it may be possible to choose grass species which are less impacted by the allelopathic chemicals of S. canadensis in order to prevent the dominancy of this aggressive species