Microstegium vimineum in the EPPO region: addition to the EPPO Alert List
Considering the potential of invasiveness and the limited presence of Microstegium vimineum in the EPPO region, the Secretariat considered that this species could usefully be added to the EPPO Alert List.
Why: Microstegium vimineum (Poaceae) is an annual grass native to Asia. The plant can be introduced involuntarily as a contaminant of bird seeds, soil and hay. Within the EPPO region, its distribution is still limited. Because this plant has shown invasive behaviour where it has been introduced elsewhere in the world and is still limited in the EPPO region, it can be considered an emerging invader in Europe.
Geographical distribution
EPPO region: Turkey, Russia (region of Primorsk, native).
Asia (native): China, India, Japan (Hokkaido, Honshu, Kyushu, Ryukyu, Shikoku), Republic of Korea, Malaysia, Nepal, Philippines, Taiwan, Thailand.
Central America: Puerto Rico (invasive)
North America (invasive): USA (Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, West Virginia).
Note: in Turkey, it is not recorded whether the species is casual or naturalized. The plant is present in North-East Anatolia, immediately near the town of Espiye, on a wet and seasonally-flooded river margin on gravels and sands of the river Espiye (Scholt and Byfield, 2000).
Morphology
M. vimineum is an annual grass which resembles a small bamboo. The plant produces a sparse, very short root system. It is usually 0.6-1 m in height, and the reclining stems can grow up to 1 m long. In unfavourable conditions, the plant can be as little as 10-20 cm tall, and is capable of flowering. The lanceolate leaf blades are 5-8 cm long, 2-15 mm wide, sparsely pubescent on both sides. The ligules are membranous, usually ciliate, and are 0.5-2 mm long. The fruit or caryopsis (grain) is yellowish to reddish, and ellipsoid in shape, 2.8-3.0 mm long.
Biology and ecology
In the northern hemisphere, seeds germinate in late spring and flower in mid-autumn. The plant reproduces vegetatively by rooting at nodes. It reproduces sexually as well and can produce 100 to 1000 seeds per plant. Seeds are dispersed by water, animals, and through human activities on clothing and vehicles. Seeds stored in the soil may remain viable for 5 years. Seeds may need stratification before germination, they can survive floods of 10 weeks. The plant appears to be associated with moist, acidic to neutral soils that are rich in nitrogen. It occurs opportunistically in areas of open soil that are generally not already occupied by other species. Although a C4 grass, the plant is adapted to low light conditions. The coldest winter temperature at which invasive populations of M. vimineum occur is approximatively -21°C to -23°C.
Habitats (adapted from Corine Land Cover nomenclature)
Arable land: early successional fields.
Mixed forests: forested slopes, particularly under disturbed canopy.
Banks of continental water, riverbanks/canalsides: forested wetlands.
Road and rail networks and associated land: roadside ditches, gas and power line corridors.
Other artificial surfaces (wastelands): it readily invades and is most common in disturbed, shaded areas like floodplains that are prone to natural scouring, and areas subject to mowing, tilling and other soil disturbing activities.
Green urban areas, including parks, gardens, sport and leisure facilities.
Pathways
In the early 1900s, M. vimineum was used extensively as a packing material for porcelain, especially fine China porcelain, which may have contributed to its entry into the USA. The plant has been reported as a contaminant of bird seed, soil and hay. It has not been documented as being intentionally planted as an ornamental, for erosion control or for forage.
Impacts
M. vimineum produces nearly monospecific stands that replace natural communities. Once established, it is able to crowd out native herbaceous vegetation in wetlands and forests within three to five years. The amount of available nitrate in the soil has shown to increase under stands of this grass. Additionally, populations of M. vimineum alter quality nesting for wildlife (e.g. quails) and creates excellent habitat for rats (e.g. cotton rats).
Control
Hand pulling is the preferred method of removal when operated at the end of the summer, i.e. before the seed release, and when new seedlings have germinated. Mowing is effective if carried out in late summer as well. Grazing is not a control option since cattle, deer and even goat do not feed on the plant. Spring burns are ineffective since seeds will germinate after the burn, but burns in the late fall may control the species.
Large patches can be sprayed with grass-selective herbicides.
Sources
Global Invasive Species Database – Microstegium vimineum. http://www.issg.org/database/species/ecology.asp?si=686&fr=1&sts
Scholz H, Byfield A (2000) Three grasses new to Turkey. Turkish Journal of Botany 24, 263-267. http://journals.tubitak.gov.tr/botany/issues/bot-00-24-4/bot-24-4-7-98001.pdf
Weber E (2003) Invasive Plant Species of the World. CABI Publishing Wallingford, (UK) pp. 548, p. 269.