Competition between pink muhly grass and native plant species: Is it really a harmful invasive species?

Abstract

Pink muhly grass (Muhlenbergia capillaris Trin.) is an exotic species in South Korea and is popular worldwide as an ornamental grass for landscaping purposes. The Ministry of Environment in South Korea has categorized this species as an “Ecosystem Hazard Class 2” plant, requiring long‐term monitoring to assess its ecological impacts on native species and communities. In this study, a 2‐year greenhouse experiment was conducted using M. capillaris and 17 native plant species (6 annuals, 8 nonwoody perennials, and 3 woody perennials) to test the hypothesis that if M. capillaris is an invasive species, it will negatively affect the establishment and growth of native plants in competitive pairings compared with controls (native species grown in monoculture). Results showed that the mean canopy cover of native plants in competition with M. capillaris was not significantly different from monocultures of the corresponding native species. There were also no significant differences in mean aboveground biomass production between native species growing with M. capillaris compared to corresponding native monocultures. Results indicate that M. capillaris did not significantly affect the establishment and growth of the 17 native species investigated. The minimal impacts suggest that M. capillaris may not be a harmful invasive species, but further monitoring of its spread will be required to test these findings under natural conditions.