Competition in a changing world: invasive aquatic plant is limited by saltwater encroachment

Competitive interactions between native and nonindigenous species occur under conditions of ongoing environmental alterations related to urbanization climate change, presenting a challenge understanding invasiveness. Indigenous submerged aquatic vegetation have been negatively impacted by nutrient enrichment saltwater intrusion, while simultaneously experiencing rapid spread in competitors. To better predict future shifts freshwater macrophyte community dominance, investigations need consider how these multiscale disturbances influence competitiveness macrophytes. Using an outdoor greenhouse mesocosm setup for approximately 19 weeks over the course subtropical winter, we experimentally examined enrichment, salinity, interaction both factors competitive with moderate salinity tolerance, wild celery (Vallisneria americana), highly invasive lower hydrilla (Hydrilla verticillata). We tested composition (hydrilla monoculture, or biculture), (0, 4, 8), fertilization (ambient fertilized) on biomass production, allocation, morphological metrics as responses condition interspecific competition. Fertilizer enhanced leaf area (more than twofold) shifted allocation toward aboveground biomass, but did not enhance competitiveness. Salinity affected (by 7.5%–67.8%) 4%–15%) also reduced belowground production 6%–25%) An effect fertilizer influenced growth, however combined outcomes. The lack evidence advantage this study demonstrates that exposure sufficiently limits plant's abilities subsequent suppression species.