First report of Cornus alternifolia and Cornus amomum in Lithuania
In Lithuania, 90 woody alien species have been recorded and 6 are legally recognised as invasive alien species. Cornus alternifolia and Cornus amomum (Cornaceae) are native to eastern North America. C. alternifolia is distributed from Quebec to Ontario to the southern part of the United States and grows as a shrub or a tree up to 12 m tall. C. amomum is naturally distributed from Maine to Florida and grows as a shrub up to 5 m tall. Both species were introduced into Lithuania in the first half of the 19th century. Within the EPPO region, C. alternifolia has been recorded as a casual alien species in Slovakia while C. amomum has not been reported to-date. In 2019, C. alternifolia was found in the wild in an alluvial forest habitat in Vilnius (southeastern Lithuania) where the population occurred over an area of approximately 0.5 ha. The population consisted of approximately 900 individuals ranging in height (approximately 100 from 1 m to 3.5 m and 300 individuals from 0.5 m to 1 m). The number of seedlings and small individuals (less than 0.5 m in height) was estimated around 500 individuals. C. amomum was first observed in the natural environment in Northern Lithuania in the district of Šiauliai on the banks of the Bubiai Water Reservoir. Four mature individuals with unripe fruit and several younger individuals were dispersed over 120 m2. The authors highlight that the probable occurrence of both species in the natural habitats is a result of the fruit being eaten by birds and subsequently spread. The authors recommend that both species should be monitored and where necessary eradicated.
Sources
Petrulaitis L, Gudžinskas Z (2020) The first records of two alien woody species, Cornus alternifolia and Cornus amomum, in Lithuania. BioInvasions Records 9 (in press).