The study aims at contributing to the discussion in which way Bromus erectus invaded into southernmost
Lower Saxony throughout the 20th century. Basing on the data of distribution, and on the
evaluation of the ratio “cover of Bromus erectus/cover of Brachypodium pinnatum” in numerous
phytosociological publications, it should be considered that the path of invasion did not lead straightly
from S to N. The direction along the Eastern and Northern surrounding of the Harz mountains, and
from here southwards through the Leine valley seems more likely. This invasion was mainly released by
the strong reduction of grazing by sheep and goats. On the other hand this change in land use favours
the growth of shrub vegetation and, thus, reduces the area accessible to Bromus erectus
