Competitive Interactions Between Alligator Weed and Mukunuwenna When Nutrient Availability Varies

Abstract

Spread of invasive species may destruct natural resources in an ecosystem as well as threaten the human use of the ecosystem resources. Riparian and wetland ecosystems are vulnerable to invasion because of the nutrient rich runoffs entering into them. Alligator weed (Alternanthera philoxeroides) is a dense mat-forming aquatic plant, which may spread to adjacent terrestrial systems such as riparian ecosystems and wetlands. It is observed that this species is able to invade habitats used to be occupied by Mukunuwenna (Alternanthera sessilis), which is a native species and a popular leafy vegetable in Sri Lanka. Therefore, this study is focused on the competition between these species in colonisation stage, under three nutrient conditions. Each pot had total of 4 plants, either monoculture of one of the species or different combinations of the species. Plant community composition was decided according to a replacement series.