The vegetation of rich fens (Sphagno warnstorfii-Tomentypnion nitentis) at the southeastern margins of their European range

Question : Rich fens of the Sphagno warnstorfii-Tomentypnion nitentis alliance require a specific combination base richness and climate to occur. Their rarity at southeastern margins their European range has previously prevented rigorous vegetation classification. We asked how many associations may be delimited here whether some them are restricted high Balkan Mountains showing endemicity. Study area Entire territories Bulgaria Romania. Methods compiled all available vegetation-plot records, including hitherto unprocessed data. classified by both divisive (modified TWINSPAN) agglomerative (beta-flexible clustering) numerical classification method, with OPTIMCLASS1 applied set number clusters. A semi-supervised approach (k-means) was additionally confirm Southern-Carpathian (Romania) rich fens, where taxa Differences in elevation were tested one-way ANOVA Tukey’s pairwise test. Results Three three occur Bulgaria, from only one association had been reported. Two characterised Sphagnum contortum Southern-European species but not Romania, lower elevations around 1,200 m, higher 2,000 m pH is lower. One lower-elevation (around 1,300 m) S. warnstorfii teres shared between Central Europe. Conclusions have described new high-mountain association, two subassociations that differ successional stage dominant peat moss ( , respectively). These could reconsidered when more data other countries available. Europe rare, diverse vegetation, deserving further attention nature conservation authorities scientists. Taxonomic reference The nomenclature harmonized following Euro+Med PlantBase (Euro+Med 2021) for vascular plants Hill et al. (2006) bryophytes, except Angelica pancicii accepted as separate taxon (Andreev 1992; Delipavlov 2003). Critical taxa, always reliably differentiated field literary sources, merged aggregates: Alchemilla vulgaris agg. (all species), Anthoxanthum odoratum A. alpinum ), Molinia caerulea M. arundinacea subsp. freyi Palustriella commutata P. falcata Plagiomnium affine elatum ellipticum palustre centrale ). Syntaxonomic Peterka (2017) alliances.