Potential distribution of Humulus scandens along rivers in Romania
Humulus scandens (Cannabaceae: EPPO A2 List) is native to Asia and in the EPPO region the species is present in Austria, Belgium, the Czech Republic, France, Germany, Italy, Hungary, Romania, Serbia, Slovakia, Slovenia, Switzerland, and Ukraine. The species thrives along riversides, where the seeds easily enter the waterbody and are transported throughout the river catchment. In Romania, H. scandens was first observed in 1942 in disturbed habitats in the south of the country. Several other occurrences from the west and south-west regions were reported along the Danube and some of its tributaries. Later observations were collected from North-Western Romania, along water channels and shrubbery forest edges. To gain a better understanding of the potential distribution of H. scandens in the southern and central parts of the Danube basin, landscape and climatic variables (bioclimatic variables from WorldClim) were collected along with data on occurrences and inputted into a species distribution model. H. scandens is highly influenced by milder climates and areas with constant flooding events and the model showed that the distance to a water body was an important factor. The model showed that the Tisa basin and its tributaries can be areas of high invasion risk. The Danube can act as a dispersion corridor for major river systems in Southern Romania, though the dispersion capability dropped in steppe areas with higher aridity and limited water course network. Predicting the potential areas of high invasion risk is an important approach when preventing or managing invasive alien plants with limited resources. This can help focus prevention efforts in areas of high risk.
Sources
Urziceanu, MM, Cîs lariu AG, Nagoda E, Nicolin AL, Măntoiu DS, Anastasiu P (2022) Assessing the invasion risk of Humulus scandens using ensemble species distribution modeling and habitat connectivity analysis. Plants 11, 857. https://doi.org/10.3390/plants11070857