The higher units of dark coniferous forests of eastern part of Europe, Southern Urals and Western Siberia in the Braun-Blanquet system

Classification of dark coniferous forests of the Eastern part of Europe, Southern Urals and Western Siberia was performed using data set of 55 low-rank syntaxa (association, subassociation and variant), results of cluster analysis (Ward method, Euclidian distance) and DCA ordination (Fig. 1, 2). The synoptic table of dark coniferous forests syntaxa (Table) was developed and clarification of their diagnostic features was made. In accordance with the “Vegetation of Europe ….” (Mucina et al., 2016), the entire diversity of the higher units of the dark coniferous forests was classified into two classes, two orders and eight alliances. At the highest hierarchical level, two classes were clearly distinguished — the Asaro europaei–Abietetea sibiricae Ermakov et al. in Willner et al. 2016 and Vaccinio-Piceetea Br.-Bl. in Br. Bl. et al. 1939. The class Asaro europaei–Abietetea sibiricae includes subnemoral dark coniferous forests occurring in southern part of forest zone in the Southern Urals and Western Siberia. These forests combine some important features of boreal and nemoral vegetation in the phytocoenotic structure (physiognomy) and floristic composition. Therefore, the diagnosis of the class Asaro europaei–Abietetea sibiricae is based on a combination of the following criteria. 1. The absolute predominance of cold-resistant boreal tree species (Picea obovata, Pinus sibirica, Abies sibirica) in the higher layer makes it impossible to assign them to the higher units of nemoral vegetation and fundamentally distinguishes them from the class Carpino–Fagetea sylvaticae Jakucs ex Passarge 1968. 2. The high constancy values of widespread Eurasian shade-tolerant species associated dominantly with dark coniferous forests: Dryopteris expansa, D. carthusiana, D. assimilis, D. dilatata, Phegopteris connectilis, Diplazium sibiricum, Gymnocarpium dryopteris, G. robertianum, Athyrium filix-femina, Oxalis acetosella, widespread European-Siberian nemoral species: Daphne mezereum, Dryopteris filix-mas, Viburnum opulus, Stachys sylvatica, Galium odoratum, Geranium robertianum, Festuca altissima, Asarum europaeum, Actaea spicata, Brachypodium sylvaticum, Aegopodium podagraria, Viola mirabilis, Sanicula europaea, Festuca gigantea, as well as nemoral species with narrower ranges located in southern Siberia: Osmorhiza aristata, Anemonoides altaica, Corydalis bracteata, Erythronium sibiricum, Anemonoides caerulea, Myosotis krylovii, Euphorbia Pilosa and European species with eastern boundaries of ranges running in the southern Urals: Ulmus glabra, Pulmonaria obscura, Polygonatum multiflorum, Cicerbita uralensis, Geum urbanum, Carex pilosa, Euonymus verrucose. All these species were included in diagnostic combination of the Asaro europaei–Abietetea sibiricae. 4. Absence or rare occurrence of typical boreal species (characteristic of the class Vaccinio-Piceetea) in the shrub and ground layers. Currently, the class Asaro europaei–Abietetea sibiricae is represented by one order Abietetalia sibiricae Ermakov 2006, since the analysis of the possibility of including the Central European sub-nemoral dark coniferous forests of the order Athyrio–Piceetalia abietis, close to them dark coniferous forests of Eastern Europe and Euxinian forests of the Abieti nordmannianae–Piceetalia orientalis Coban et Willner 2019 has not yet been analyzed. Synopsis of the Asaro europaei–Abietetea sibiricae. Cl. Asaro europaei–Abietetea sibiricae Ermakov, Mucina et Zhitlukhina in Willner et al. 2016. Ord. Abietetalia sibiricae Ermakov 2006. All. Milio–Abietion sibiricae Zhitlukhina ex Ermakov et al. 2000. Suball. Cruciato krylovii–Abietenion sibiricae Ermakov in Ermakov et al. 2000. Ass. Asaro europaei–Abietetum sibiricae Zhitlukhina ex Ermakov et al. 2000. Ass. Violo biflorae–Abietetum sibiricae Ermakov 2000. Ass. Violo uniflorae–Abietetum sibiricae Ermakov 2000. Ass. Anemonoido baicalensis–Abietetum sibiricae Ermakov et Stepanov in Ermakov 1995. Suball. Milio effusi–Abietenion sibiricae Ermakov in Ermakov et al. 2000. Ass. Cacalio hastatae–Abietetum sibiricae Ermakov 2000. Ass. Geranio robertiani–Tilietum sibiricae Ermakov et Maskayev in Ermakov 1995. Ass. Saussureo latifoliae–Abietetum sibiricae Ermakov 2013. Ass. Filipendulo ulmariae–Abietetum sibiricae Lashchinskiy 2009. All. Filipendulo ulmariae–Populion tremulae Ermakov in Ermakov et al. 2000. Ass. Dactylido glomeratae–Abietetum sibiricae Ermakov in Ermakov et al. 2000. Subass. D. g.–A. s. vicietosum sylvaticae Lashchinskiy 2009. Ass. Festuco giganteae–Populetum tremulae Ermakov 2000. Ass. Geranio sylvatici–Populetum tremulae Ermakov 2000. Ass. Saussureo latifoliae–Populetum tremulae Ermakov 2000. Ass. Anemonoido jenisseensis–Populetum tremulae Ermakov 1995. Ass. Equiseto pratensis–Padetum Falinski ex Ermakov et al. 2000. Ass. Matteuccio–Populetum tremulae Lashchinskiy 2009. All. Aconito septentrionalis–Piceion obovatae Solomeshch et al. in Martynenko et al. 2008. Suball. Tilio cordatae–Piceenion obovatae Martynenko et al. 2008. Ass. Brachypodio sylvaticae–Abietetum sibiricae Martynenko et al. 2007. Ass. Violo collinae–Piceetum obovatae Martynenko et Zhigunov in Martynenko et al. 2005. Ass. Chrysosplenio alternifolii–Piceetum obovatae Martynenko et al. 2007. Ass. Carici rhizinae–Piceetum obovatae Solomeshch et al. 1993. Ass. Frangulo alni–Piceetum obovatae Martyenko et Zhigunova 2007. Suball. Aconito septentrionalis–Piceenion obovatae Martynenko et al. 2008 Ass. Lathyro gmelinii–Laricetum sukaczewii Ishbirdin et al. 1996. Ass. Cerastio pauciflori–Piceetum obovatae Solomeshch et al. ex Martynenko et al. 2008. Ass. Asaro europaei–Piceetum obovatae Martynenko 2009 prov. All. Carici macrourae–Abietion sibiricae Lashchinskiy et Korolyuk 2016. Ass. Caragano arborescentis–Piceetum obovatae Lashchinskiy et Pisarenko 2016. Ass. Aegopodio padagrariae–Abietetum sibiricae Lashchinskiy et Korolyuk 2015. Ass. Melico–Abietetum sibiricae Ermakov et Lapshina 2013. In accordance with the concept proposed in the “Vegetation of Europe …” (Mucina et al., 2016), all boreal dark coniferous forests of the eastern part of Europe, Southern Urals and Western Siberia were assigned to the class Vaccinio-Piceetea and order Piceo obovatae–Pinetalia sibiricae Ermakov 2013. Diagnostic species of the order are Abies sibirica, Picea obovata, Pinus sibirica, Sorbus sibirica, Calamagrostis obtusata, Cerastium pauciflorum, Stellaria bungeana. The results of quantitative classification, ordination (Fig. 1, 2) and comparative syntaxonomic analysis of dark coniferous forests made it possible to correct the system of alliances. Syntaxonomic synopsis of the order Piceo obovatae–Pinetalia sibiricae Ermakov 2013. All. Aconito rubicundi–Abietion sibiricae Anekhonov et Chytrý 1998 Ass. Aconito septentrionalis–Piceetum obovatae Zaugolnova et Morozova in Zaugolnova et al. 2009 Ass. Bistorto majoris–Piceetum obovatae Martynenko 2009 ass. nov. prov. Ass. Adenophoro lilifoliae–Piceetum obovatae Martynenko 2009 ass. nov. prov. Ass. Linnaeo borealis–Abietetum sibiricae Lashchinskiy et Korolyuk 2015. Ass. Scutellario galericulatae–Piceetum obovatae Lashchinskiy et Pisarenko 2016. Ass. Rubo arctici–Abietetum sibiricae Ermakov et Makhatkov 2011. All. Pino sibiricae–Abietion sibiricae Ermakov in Ermakov et Lapshina 2013. Ass. Pino sibiricae–Abietetum sibiricae Ermakov et Makhatkov 2011. Ass. Ledo palustris–Abietetum sibiricae Ermakov et Lapshina 2013. All. Carici digitatae–Piceion obovatae all. nov. (described in this paper). Diagnostic species: Equisetum scirpoides, Chamaecytisus ruthenicus, Vicia cracca, Moehringia lateriflora, Cypripedium guttatum, Seseli krylovii, Campanula rotundifolia, Carex alba, C. digitata, Saussurea controversa, Gymnocarpium robertianum, Cortusa mathioli, Adonis sibirica, Cardamine trifida, Tephroseris integrifolia, Zigadenus sibiricus, Rhizomatopteris montana. Ass. Equiseto scirpoidis–Piceetum obovatae Martynenko et Zhigunova 2004. All. Vaccinio myrtilli–Piceion obovatae all. nov. prov. Ass. Vaccinio myrtilli–Piceetum obovatae ass. nov. (described in this paper) The ass. Carici macrourae–Abietetum sibiricae Ermakov et Lapshina 2013 can not be included in any existing alliances.