1 Oct 2021

Phenology of Competitive Interactions and Implications for Management of the Invasive Wetland Plant Alternanthera philoxeroides

Purpose: Phenological differences between invading plants and members of recipient communities may increase the success of invaders because of priority effects. Thus, the application of management when the invader has a phenological advantage (for example, early in the year) can benefit other species by increasing resource availability. This technical note summarizes results from a combination of field observations and a mesocosm experiment to explore whether phenological differences between the invasive wetland plant, alligatorweed (Alternanthera philoxeroides [Mart.] Grseb.), and resident species contribute to alligatorweed success. We documented over two years the early-season growth of alligatorweed and other species at 12 sites in Louisiana, USA. We then conducted a subsequent mesocosm competition experiment between alligatorweed and a common wetland emergent species, spotted lady’s thumb (Persicaria maculosa [L.] Small), over a full year to detect differences in timing of growth and competitive interactions under two fertilizer levels.