Comparison of allelopathic effects of five invasive species on two native species

Abstract

Abstract Recent studies have found that allelopathy can be an important mechanism of plant invasions. Alliaria petiolata, Lonicera maackii, Ranunculus ficaria, Celastrus orbiculatus, and Microstegium vimineum are invasive species found in the Midwestern USA. We investigated the comparative direct and indirect allelopathic effects of these five species in a laboratory setting using leaf extracts in a germination experiment and a growth experiment. Results illustrate that the effect of each invasive species varied with target species and with life stage. Extracts of L. maackii and R. ficaria had the largest overall effects (∼50% reduction) on germination across both species, but effects of extracts varied by target species. Extracts of A. petiolata and C. orbiculatus had a greater effect on germination of E. hystrix than on C. fasciculata. Extracts of L. maackii, M. vimenum, and R. ficaria had larger inhibitory germination effects on C. fasciculata than on E. hystrix. For growth of E. hystrix after 8 wk, C....