Classification of common hazel scrub vegetation in Slovakia

Approaches for classifying common hazel-dominated communities differ substantially among countries in Europe. Based on differing criteria, authors have classified identical communities within different higher syntaxa or have classified different communities within one unit. In Slovakia, the situation has been similar. These facts motivate us to accomplish (i) complex syntaxonomical revision of common hazel scrub in Slovakia, ii) comparison of West Carpathian communities with relevant Alpine and Hercynian ones, and iii) identification of the main environmental drivers of variation in their floristic composition. Based on the numerical classification of 415 relevés, two main units were distinguished. They were identified with the Pruno spinosae-Coryletum Jurko 1964 and the Lonicero nigrae-Coryletum Jurko 1964 associations. The main predictors of species’ compositional variability were found to be temperature, followed by moisture, light, and soil reaction. After comparison with all relevant communities from Alpine and Hercynian regions, both associations were classified within the alliance Populo tremulae-Corylion avellanae Br.-Bl. ex Jurko 1964 nom. invers. propos., the order Prunetalia spinosae Tx. 1952 and the class Crataego-Prunetea Tx. 1962. Relations with the other hazel-dominated communities and their classification are discussed in detail.