Alien grasses (Poaceae) in the flora of the Eastern Alps.

This overview presents the recent knowledge on non-native (archaeophytic, neo-phytic and regionally neophytic) grasses in Austria and the Eastern Alpine territory. In total, 220 taxa are discussed, 175 of them are neophytes, 19 are regional neophytes, 3 are subspontaneous garden escapes and 23 are quoted as archaeophytes. By comparison with Walter & al. (2002) and Fischer et al. (2008), the impact of neophytes in the recent past can be estimated for the Austrian part of the territory, where 152 alien taxa are actually known, 32 (21 percent) were newly recorded in the last decade, among them, 6 are invasive or suspectedly invasive.

Meanwhile, several species are naturalized, but the share of invasive and potentially invasive taxa (44 species, 20 percent) is surprisingly low. They are subject of enhanced attention. Commonly, invasive characteristics are considered only as a suppression of the native flora, but an impact is also caused by introgression (via hybridization of aliens with closely related native taxa), and such processes may remain undetected for a long time.

Increasing traffic, fitout of transport routes and their maintenance support the propagation of alien species as well as globalized product flows in general, especially trading of ornamental plants, seeds and horticultural accessories. Moreover, climatic change may facilitate a spread of species requiring warmer environmental conditions. It will need some more legal regulations to control this trend. Considering that, expertise of botanists, as well as of experienced horticulturists is indispensable.