Wystepowanie i udzial Lolium perenne w zbiorowiskach lakowo-pastwiskowych Wielkopolski

On the basis of 4000 phytosociological surveys taken using the Braun-Blanquet method, it was found that Lolium perenne occurs in meadow-pasture communities of 5 phytosociological classes, namely: Molinio-Arrhenatheretea, Phragmitetea, Koelerio glaucae-Corynephoretea canescentic, Scheuchzerio-Caricetea fuscae and Agropyretea intermedio-repentis. The highest proportion of this species occurred in Molinio-Arrhenatheretea, which is associated with site conditions and the level of utilisation. The share of Lolium perenne in the identified communities showed variations between river valleys. It was found to occur most frequently and numerously in valleys of such smaller rivers as: the Barycz, the Rów Ostroroski, the Mogilnica, the Sama Szamotulska. The development of degradation forms of communities in the Molinio-Arrhenatheretea class containing Lolium perenne was associated mainly with the impact of the anthropogenic factor, in particular with limited fertilisation and grazing (sometimes with its complete abandonment). In communities of the remaining classes, the factor limiting the share of Lolium perenne was site conditions, primarily poor soil fertility and different ways of utilisation. In areas situated at foothills and seaside, Lolium perenne occurs less frequently and at a lower share in meadow-pasture communities, which can be associated with utilisation intensity and non-forage functions.