Formalized classification and nomenclatural revision of thermophilous deciduous forests (Quercetalia pubescentis) of Bosnia and Herzegovina

Thermophilous deciduous forests of Quercetalia pubescentis are widespread in Bosnia and Herzegovina (B&H), where they occupy about 11% of the national territory and account for about 20% of the total forest area. This paper provides their formalized classification and nomenclatural revision, based on 274 releves from the literature and 399 releves collected during intensive field research. The Cocktail method was used for supervised classification, which resulted in 17 associations recognized for B&H. Additionally, one new association emerged after semi-supervised classification of releves not classified by Cocktail. The following associations were recognized, and characterized by species composition, ecology and distribution: 1. Querco pubescenti-Carpinetum orientalis; 2. Rusco aculeati-Carpinetum orientalis; 3. Carici hallerianae-Quercetzim pubescentis; 4. Cruciato glabrae-Carpinetum orientalis; 5. Seslerio autumnalis-Quercetum pubescentis; 6. Aristolochio luteae-Quercetum pubescentis; 7. Asparago tenuifolii-Quercetum pubescentis; 8. Seslerio autumnalis-Ostryetum carpinifoliae; 9. Rusco aculeati-Ostryetum carpinifoliae; 10. Querco pubescenti-Ostryetum carpinifoliae; 11. Quercetum fi-ainetto-cerridis; 12. Fraxino orni-Quercetum cerridis; 13. Lathyro nigri-Quercetum petraeae; 14. Aceri obtusati-Quercetum petraeae; 15. Cytiso hirsuti-Quercetum petraeae; 16. Festuco diymejae-Quercetum petraeae; 17. Potentillo micranthae-Quercetum petraeae; 18. Seslerio autumnal's-Quercetum petraeae. The validity and legitimacy of associations were checked and they were validated and corrected as needed, strictly following the rules of the International Code of Phytosociological Nomenclature. A complete list of synonyms has been given for every association, with an indication of the article of the Code according to which the name must be rejected. The associations were assembled into four groups, following the criterion of dominant species in a tree layer, in order to present differences and similarities in floristic composition between associations of the same type, i.e., dominated by the same tree species. An ecogram was drawn displaying the relative ecological range of each association along soil pH and moisture gradients. The largest number of associations (13) occurs in the Mediterranean region; the Dinaric and Pre-Pannonian regions each harbour ten associations, while there are only five associations in the Transitional Illyrian-Moesian region. Seven syntaxa previously reported for thermophilous deciduous forests of B&H were not recognized during the analysis. A list is given of all nomina nuda that could not be resolved and ascribed to synonymy with accepted associations.