Effects of different intensities of artificial light at night on functional traits of invasive and native plants

Abstract Artificial light at night (ALAN) is an emerging component of global change and may increase the risk of plant invasion. However, the effects of different intensities of ALAN on the growth of invasive and native plants remain unclear. We conducted a controlled experiment in which five pairs of invasive and native plants from different families were grown separately under three light regimes: ambient light, low ALAN, and high ALAN. Our study showed that the total biomass of both invasive and native plants increased significantly under low-intensity ALAN. However, under high-intensity ALAN, the total biomass of invasive plants increased significantly, whereas the biomass of native plants significantly decreased. These findings indicate that invasive plants can better utilize light energy and have more effective photosynthetic responses under ALAN, while the photosynthesis of native plants is inhibited. The leaf dry matter content and leaf nitrogen content of invasive plants were significantly higher than those of native plants under ALAN, which significantly improved the photosynthetic nitrogen use efficiency of invasive plants. This indicates that invasive plants have stronger phenotypic plasticity and nitrogen-distribution strategy under ALAN. In summary, the enhanced physiological response of invasive plants under different intensities of ALAN may contribute to their continued spread and dominance in the ecosystem.