The checklist of alien and cryptogenic bryophytes in Austria (2nd edition).
We present the second edition of the checklist of alien and cryptogenic bryophytes (Bryophyta) in Austria. In total, four alien bryophyte species are reported, of which three are established, and for one it is unknown if it is casual or established. In addition, four cryptogenic species (i.e. species that are likely alien, but their biogeographic status is uncertain) are included, of which one is casual and one is extinct. In comparison with the first checklist of alien bryophyte species for Austria published in 2002, the number of alien or cryptogenic bryophytes has risen by four species. Most alien or cryptogenic bryophytes in Austria are native to continents of the Southern Hemisphere. Most invaded ecosytems in Austria are man-made habitats, fields, forests and mires. One species (Campylopus introflexus) is assumed to locally cause negative environmental impacts.