How Eutrophication Promotes Exotic Aquatic Plant Invasion in the Lake Littoral Zone?

Eutrophication and exotic species invasion are key driversof theglobal loss of biodiversity and ecosystem functions in lakes. We selectedtwo exotic plants (Alternanthera philoxeroides and Myriophyllum aquaticum) and twonative plants (Myriophyllum spicatum and Vallisneria spinulosa) to elucidatethe effect of eutrophication on exotic plant invasiveness. We foundthat (1) elevated nutrient favored invasion of exotic species andinhibited growth of native plants. Species combinations and plantdensities of native plants had limited effects on the resistance toinvasion of the exotics. (2) A. philoxeroides featured the tightest connectivity among traits, which is consistentwith its high competitive ability. Although eutrophication causedphysiological stress to A. philoxeroides, it could effectively regulate enzyme activity and alleviate thestress. (3) M. aquaticum possessedstrong tolerance to habitat disturbance and was highly disruptiveto the surrounding plants. Eutrophication will exacerbate the adverseeffects of M. aquaticum on the littoralecosystem. (4) Nutrient enrichment reduced the biomass and relativegrowth rates of V. spinulosa and loweredphenolics and starch contents of M. spicatum, thereby making them more susceptible to habitat fluctuations. Overall,our study highlights how eutrophication alters the invasiveness ofexotic plants and the resistance of native plants in the littoralzone, which is of relevance in a world with intensified human activities.

Our study elucidates how eutrophicationpromotes aquaticplant invasion based on 28 plant traits and highlights the importanceof mitigating eutrophication to combat plant invasion.