Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Competitive effects between Ageratina adenophora (Asteraceae) and Setaria sphacelata (Gramineae).

Abstract

Objective: An experiment was conducted to study the interspecific competitive interaction between Ageratina adenophora and Setaria sphacelata at different densities, and to explore the methods of controlling the invasive weed A. adenophora displaced by S. sphacelata. Method: The two perennial species were grown for 2 years in monoculture and mixture on an experimental densities gradient. The above- and belowground biomass of the two species were measured and the growth response and relative competitive ability were evaluated. Result: The total biomass, relative yield and competitive balance index of S. sphacelata were significantly higher than those of A. adenophora, the relative yield total was significantly low. The total biomass of A. adenophora at 20, 45 and 175 plants/m2 in mixture decreased by 33.0, 38.5 and 70.1% compared to those in monoculture, respectively. However, the total biomass of S. sphacelata at the same density between monoculture and mixture showed no significant difference. The ratios of root mass vs. shoot mass of S. sphacelata in mixture were significantly lower than those in monoculture. However, the ratios of root mass vs. shoot mass of A. adenophora in the mixture were significantly higher than those in monoculture. Conclusion: There was a significant mutual antagonism between A. adenophora and S. sphacelata compared to A. adenophora, the relative competitive ability of S. sphacelata was higher, which decreased heavily the growth of A. adenophora mainly by shoot competition. It will be a promising strategy for replacement control of A. adenophora by using S. sphacelata as a competitor.