Abstract
Rising biological invasions continue to threaten biodiversity conservation worldwide. To protect native ecosystems and biodiversity, improve resilience against invasions, and lower ecological management costs, it is crucial to identify native plant species that can endure the competitive pressures from invasive plants. This greenhouse study examined the competition between Solidago canadensis and 32 native plant species to identify key functional traits of these native plant species that influence their competitive effects on and responses to S. canadensis. The results indicated that S. canadensis seedlings were unable to suppress the growth of most of the native species studied, while most native species could significantly suppress growth of S. canadensis, reducing its biomass by 12-92%. The suppression effects by native plants were closely related to their root functional traits. Specifically, annuals with higher root-shoot ratio, specific root lengths, stem biomass, plant height by day 10, and smaller number of root tips showed stronger inhibition of S. canadensis. On the other hand, perennials with smaller average root diameter, or greater root biomass and plant heights by day 60, were also more inhibitory towards S. canadensis. This study concluded that the competitive effect of seedlings of S. canadensis have weaker competitive impacts compared to most the studied native plants. Root traits are essential in the competition between native plants and S. canadensis, potentially aiding in the identification of native plant species with high resistance to invasion.