Artificial light at night alters the relative dominance of invasive plants in a nutrient-dependent manner across native species richness levels

Non-native plant invasions pose a global challenge, yet how nutrient enrichment and artificial light at night (ALAN) interact with native-community species richness to shape invasive-plant performance and community-level dominance remains unclear. We conducted a multispecies greenhouse experiment in which target invasive species and native communities were established simultaneously under fully crossed factorial combinations of ALAN (No-ALAN or ALAN), nutrient enrichment (low or high) and native species richness (two, four or eight species). We quantified target invasive-plant above-ground biomass, flowering probability and proportional above-ground biomass, as well as native-community and total-community above-ground biomass. Nutrient enrichment increased invader above-ground biomass by 272.88%, flowering probability by 30.39% and native-community above-ground biomass by 97.58%, although its effect on proportional invader biomass remained uncertain. ALAN did not clearly affect invader biomass or flowering but increased its proportional biomass under high-nutrient conditions by 5.74% and reduced it under low nutrients by 4.75%. Native species richness showed no clear effects on invader performance, community biomass or responses to ALAN and nutrients. Within this experimental context, invasive-plant performance was driven primarily by nutrient enrichment, with ALAN facilitating invader dominance under high-nutrient conditions, indicating that invasion outcomes were more influenced by resource availability than by native-community species richness.