Miscanthus sinensis is a perennial grass native to Asia, but since its introduction to the United States in the late 19th century, it has become both a major ornamental crop and invasive species. Previous studies of the ecology of M. sinensis in both its introduced and native ranges have suggested that it may be occupying a novel ecological niche in the introduced range. Miscanthus sinensis and its daughter species, Miscanthus × giganteus, are under evaluation as bioenergy crops; therefore, characterization of the ecology and environmental niche of M. sinensis is essential to mitigate the risk of fostering future invasion in the United States. In July 2011, we surveyed 18 naturalized M. sinensis populations spanning the U.S. distribution, covering a 6° latitudinal gradient from North Carolina to Massachusetts. Miscanthus sinensis populations ranged in size from 3 to 181,763 m2 with densities between 0.0012 and 2.2 individuals m−2, and strongly favored highly disturbed and unmanaged habitats such as roadsides and forest edges. Population size and individual plant morphology (i.e., tiller height, basal diameter, and tiller number) were not affected by soil characteristics and nutrient availability, though increased tree canopy cover was associated with reduced population size (P < 0.0001). Plant size and vigor were not significantly affected by low light availability, which supports previous suggestions of shade tolerance of M. sinensis. In summary, M. sinensis can tolerate a broad range of climatic conditions, light availability, and nutrient availability in the eastern United States, suggesting risk of further invasion beyond its current distribution in the United States.
Nomenclature: Chinese silvergrass; Eulalia japonica Trin.; Miscanthus sinensis Andersson (Poaceae).
Management Implications: Miscanthus sinensis is an extremely popular ornamental grass, and is currently naturalized across much of the eastern United States. There are > 100 named cultivars commercially available with tremendous phenotypic variation that may facilitate tolerance to a broad range of geographies in the introduced range. In this study, we surveyed 18 naturalized M. sinensis populations from North Carolina to Massachusetts to characterize the environmental, climate, and edaphic factors in invaded habitats, as well as describe individual and population-level phenotypic variation. The vast majority of M. sinensis populations are found in heavily disturbed habitats such as roadsides, utility rights-of-way, and managed forest edges. Populations ranged in size from 3 m2 to > 18 ha, and exhibited tolerance to edaphic conditions ranging in pH (4.2 to 7.3) and nutrient availability. The sampled latitudes represent a range of annual precipitation amounts and minimum temperatures—further support that M. sinensis has a broad environmental niche. Whether the populations originated from intentional plantings or from escaped ornamental plantings is equivocal. Thus, managers cultivating M. sinensis for commercial purposes (e.g., bioenergy, breeding, ornamental nursery stock) should employ best management practices to ensure that the wind-dispersed seeds do not enter sensitive habitat. It appears that M. sinensis is tolerant to disturbance common to rights-of-way (e.g., mowing), and prefers high light environments. Land managers should control M. sinensis prior to seed development to reduce propagule spread further, and integrate chemical and mechanical management to reduce population size. Because M. sinensis is such a popular ornamental grass it is unlikely that future introductions will be prevented; thus, future invasion mitigation would be facilitated by determining if specific cultivars are contrib