A formalized classification of Czech thermophilous oak forest vegetation is presented. It is based on the Cocktail algorithm, including the formulation of a set of explicit definitions of vegetation units that are used for unequivocal assignment of relevés to defined vegetation types. Eight out of 10 traditionally distinguished associations of thermophilous oak forests were formally defined: Bohemian warm and dry oak forest (Lathyro versicoloris-Quercetum pubescentis), Moravian warm and dry oak forest (Pruno mahaleb-Quercetum pubescentis), dry-mesic oak forest on basic rocky substrates (Corno-Quercetum), dry-mesic oak forest on acidic substrates (Sorbo torminalis-Quercetum), Moravian dry oak forest on acidic substrates (Genisto pilosae-Quercetum petraeae), dry-mesic oak forest on heavy soils (Potentillo albae-Quercetum), dry-mesic oak forest on sandy soils (Carici fritschii-Quercetum roboris) and dry oak forest on loess (Quercetum pubescenti-roboris). The specific features of Cocktail classifications are discussed. The complementarity of the traditional, imperfectly formalized classifications and modern formalized classifications is stressed.
Central European lowland wet meadows are habitats of great conservation interest, however, their phytosociological status has been to a large extent dependent on specific phytosociological traditions in different countries. In order to bridge the gaps between different national schemes of vegetation classification, a statistical analysis of variation in species composition of these meadows in the Czech Republic, E Austria, Slovakia, Hungary and NE Croatia was performed, using a data set of 387 geographically stratified vegetation relevés sampled at altitudes < 350 m. Principal coordinates analysiswas used to identify and partial out the noise component in the variation in this data set. The relevés were classified by cluster analysis. A new method for identifying the optimal number of clusters was developed, based on species fidelity to particular clusters. This method suggested the optimum level of classification with three clusters and secondary optimum levels with five and nine clusters. Classification based on three clusters separated the traditional phytosociological alliances of Calthion palustris and Molinion caeruleae, both with a suboceanic phytogeographical affinity, and a group of flooded meadows of large river alluvia, with a continental affinity. The latter group included the traditional alliances of Agrostion albae, Alopecurion pratensis, Cnidion venosi, Deschampsion cespitosae and Veronico longifoliae-Lysimachion vulgaris; however, the internal heterogeneity of this group did not reflect putative boundaries between these alliances as proposed in the phytosociological literature. Therefore we suggest to unite these alliances in a single alliance Deschampsion cespitosae Horvatić 1930 (the oldest valid name). Classification with nine clusters was interpreted at the level of broad phytosociological associations. Particular clusters were characterized by statistically defined groups of diagnostic species and related to macroclimatic variables.
Typology of dry-mesic oak forest vegetation of Slovakia is presented. Seven vegetation types were distinguished based on a Braun-Blanquetian relevé data analysis using a TWINSPAN classification algorithm. The identified vegetation types are related to seven syntaxa traditionally used by Central European phytosociologists: dry-mesic oak forest on sandy soils – Carici fritschii-Quercetum roboris, dry-mesic oak forest on heavy soils – Potentillo albae-Quercetum, dry-mesic oak forest on basic rocky substrates – Corno-Quercetum, dry-mesic oak forest on acidic substrates – Sorbo torminalis-Quercetum, dry oak forest on loess – Quercetum pubescenti-roboris, dry-mesic oak forest on loess – Convallario-Quercetum roboris, dry-mesic forest of Turkey oak – Quercetum petraeae-cerris. Detrended correspondence analysis was used to visualize the similarity of vegetation types. Some aspects of dry-mesic oak forest ecology, distribution and dynamics in Slovakia are discussed; their general retreat due to mesophilous tree species expansion is stressed.