Classification of mesic and wet grasslands in northwest Croatia

In this paper, 450 releves of grassland vegetation of the Molinio-Arrhenatheretea class in northwest Croatia have been classified using the agglomerative Ward's Method in the PC-ORD program. In the process of classification, the following seven groups were obtained: 1. Bromus erectus-Arrhenatherum elatius, 2. Arrhenatherum elatius, 3. Crepis biennis-Arrhenatherum elatius, 4. Luzula campestris-Holcus lanatus, 5. Deschampsia cespitosa-Betonica officinalis, 6. Equisetum palustre, 7. Oenanthe silaifolia-Alopecurus pratensis. The results of the classification for the most part correspond to the traditional syntaxonomic system. The plant communities with the largest number of releves in the data set are the association Arrhenatheretum elatioris typicum (group 2) and the association Holcetum lanati (group 4). They represent the most anthropogenically influenced grasslands of the study area. In the analysis of the ecological factors by PCA in the CANOCO program it is established that separation of the releves is influenced most greatly by moisture, followed by humus, temperature, light and soil reaction. From the standpoint of nature conservation, the wet meadows of the Molinietalia order are the most valuable, because of the notable diversity of species and communities, as well as a considerable number of threatened plant species.