A narrow-gauge railway in the Białowieża Primeval Forest as a corridor for non-native species migration

Railway territories are man-made habitats forming corridors for non-native species migration. In this study, we assessed non-native species occurrence in plant communities along a railway route of the Bialowieza Primeval Forest in Poland in relation to adjacent plant community type and microhabitat (embankment western and eastern sides of the railway track, intertrack space). An 11-km fragment of a narrow-gauge railway route in the western part of the Bialowieza Primeval Forest was investigated. This fragment was divided into 416 sections where all observed non-native species were identified, and all individuals, ramets and tussocks were counted. We discovered 12 non-native taxa, most of which (8 species) originated from North America. The highest average number of non-native species per section was recorded in the vicinity of the Circeo-Alnetum community. Statistically, more non-native species occurred on the western embankment than on the eastern one and in the intertrack space. The use of the narrow-gauge railway in the Bialowieza Forest has increased the risk of establishment of invasive species in local plant communities. The Bialowieza Forest is a refuge for native biodiversity of the utmost importance. Thus, continuous monitoring of the occurrence of non-native species is necessary for the preservation of native plant communities in the vicinity of the narrow-gauge railway route assessed in this study.