Disturbance, Trait Similarities, and Trait Advantages Facilitate the Invasion Success of Alternanthera philoxeroides (Mart.) Griseb.

Abstract

Riparian wetlands suffer serious plant invasion. Natural habitats and disturbance are two prominent environmental factors affecting the invasion process of exotic riparian invaders. In this study, a noxious invasive riparian plant, Alternanthera philoxeroides, and its native congener, Alternanthera sessilis were cultivated in three different riparian soils with different statuses of disturbance by cow manure addition. After harvest, we measured plant morphological traits including the internode length (INL), rooted node number (RNN), specific leaf area (SLA) and leaf mass ratio (LMR), and physiological traits including the maximal quantum yield (Fv/Fm), chlorophyll content (Ct), leaf nitrogen content (Nmass), leaf carbon/nitrogen ratio (C/N ratio), leaf construction cost per leaf area (CCarea), and non‐structural carbohydrate content (NSCC). Fertilization was found to improve the performances of most traits for both species similarly. Both species shared some similarities in trait values of SLA, LMR, CCarea and NSCC, and trait plasticity in NSCC in unfertilized sediments and SLA, LMR, C/N ratio, and CCarea in fertilized sediments. Moreover, compared to A. sessilis, A. philoxeroides showed some advantages in trait values of RNN in unfertilized sediments and Ct, Nmass, and C/N ratio in the most fertile treatments, and trait plasticity in INL, RNN, SLA, Ct, Nmass, and CCarea across different sediments. In conclusion, the disturbance, trait similarities, and trait advantages likely promote the invasion success of A. philoxeroides.