Formalized classification of rocky Pannonian grasslands and dealpine Sesleria-dominated grasslands in Slovakia using a hierarchical expert system
Janišová, Monika; Dúbravková, Daniela
The main aim of this paper was to perform the syntaxonomical revision of rocky Pannonian grasslands (Bromo pannonici-Festucion pallentis) and dealpine Sesleria-dominated grasslands (Diantho lumnitzeri-Seslerion) in Slovakia and to provide a reasonable tool for their identification at both, associations and alliance levels. Hierarchical expert system was formulated to achieve this aim. The syntaxonomical revision was performed based on recent and historical data available in the Slovak Phytosociological Database. The stratified data set of 16 640 relevés belonging to all syntaxa stored in this database was used to generate sociological species groups by the COCKTAIL method. In total, 18 sociological species groups were used to formulate formal definitions of alliances and associations. The assignment of a relevé to an association was allowed on condition that this relevé fulfilled the definition criteria of the given alliance. The formulation of definitions at two hierarchical levels enabled classification of typically developed vegetation to strictly defined associations as well as assignment of less developed vegetation lacking sufficient diagnostic species to broadly defined alliances. The hierarchical expert system was more effective than a simple expert system in sense of higher percentage of matched relevés. Its benefits and drawbacks were discussed in more details. Six associations of the Bromo pannonici-Festucion pallentis and three associations of the Diantho lumnitzeri-Seslerion alliances were recognized after the syntaxonomical revision. Each association was characterized by its diagnostic, constant and dominant species, physiognomical, synchorological and synecological attributes. Along with climatic-topographical (temperature and moisture) and soil-geological factors (soil reaction, soil depth, available nutrients) our analyses confirmed a strong effect of geographical location on differentiation of the studied vegetation.