Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Canopy cover size and establishment rate determine biotic resistance to Aster pilosus invasion: a priority effect.

Abstract

A restoration practitioner aims to establish native plant species following disturbance that are capable of reducing the risk of invasive plants. Identifying the common characteristics of these successful native species and/or combinations will guide restoration and improve management efficacy. A growing body of evidence indicates that species responses to invasion cannot be easily predicted by membership of pre-defined functional groups but by certain plant characteristics, related to the priority effect. Here, I initiated a pot competition experiment using the invasive Aster pilosus in South Korea. I used the additive competition design, with nine representative native plant species belonging to the annual, non-woody perennial, and woody perennial functional groups. Species identity, not functional group, determined the resistance to invasion. Monthly canopy cover data indicated that species capable of creating a large canopy early and quickly are more resistant to invasion than those exhibiting slow establishment during the early growth phase, thus supporting priority effect or niche pre-emption. Finally, performance traits of native species (canopy cover, height, biomass) were positively correlated with resistance, but stem density was not. This study suggests that any native plants with early-establishing and fast-growing would be efficiently resistant to the invasion. In addition, a mixture of four randomly chosen species was as good at resisting invasion as the monoculture of the best species, suggesting diversity effects. Together, these results improve our understanding of the fundamental principle of invasion resistance, and can be used to create valuable guidelines for better species selection and combination for in situ restoration.