Abstract
The aims of the paper are: i) to establish the coenotic affinity of each species of the Molinia caerulea complex in the southwest of Ukraine, ii) to present the results of a comparative analysis of the syntaxa in which include Molinia, iii) to explain possible reasons for the expansion of Molinia caerulea in the studied area. The study area ranges from the basins of the Upper Prut River to the Upper Siret River in Ukraine. To determine the coenotical affinity of the studied species, 134 relevés were analysed. The data analysis was carried out using the Modified TWINSPAN algorithm provided by the JUICE software. Ecological features of the communities were analyzed by means of a DCA-ordination and phytoindication assessment. It was revealed that in the studied region the species of the Molinia caerulea complex are characterized by a relatively wide coenotic and ecological range and that they can be attributed to different communities of 4 vegetation classes: Molinio-Arrhenatheretea (Polygono bistortae-Trisetion flavescentis, Molinion cearuleae, Arrhenatherion elatioris alliances), Festuco-Brometea (Bromion erecti alliance), Mulgedio-Aconitetea (Calamagrostion villosae alliance), Oxycocco-Sphagnetea (Sphagnion magellanici alliance). This paper presents the results of the floristic composition analyses outlines some ecological peculiarities and discusses the conservational values of the identified syntaxa.