The classification of oriental-beech (Fagus orientalis) forests of the Western Caucasus was developed on the basis of quantitative analysis (Ward’s method, Euclidian distance) of 200 relevés (Fig. 2) ...and comparative syntaxonomic analysis. All Caucasian beech forests were attributed to the class Carpino–Fagetea sylvaticae Jakucs ex Passarge 1968 and Euxine order Rhododendro pontici–Fagetalia orientalis Passarge 1981. The associations of floristically poor beech forests occurring on the acidic bedrocks were included in the alliance Fagion orientalis Soó 1964. These are Orobo–Fagetum orientalis Passarge 1981, Dentario–Fagetum orientalis Passarge 1981, Polysticho–Fagetum orientalis Passarge 1981, Rhododendro pontici–Fagetum orientalis Stefanov ex Tzonev et al. 2006 (syn. Rhododendro pontici–Fagetum orientalis Frantsuzov 2006), Rusco colchici–Castaneetum sativae Novák et al. 2019 and new association Rhododendro lutei–Fagetum orientalis Ermakov ass. nov. (diagnostic species — Rhododendron luteum, Cicerbita petiolata, Hedera colchica, Ilex colchica, Oreopteris limbrosperma, Vaccinium arctostaphylos, Viburnum orientale). Nomenclature type (holotypus) of the Rhododendro lutei–Fagetum orientalis Ermakov ass. nov. is relevé 14, Table 1 (field relevé nr. — 129NE19, Abkhasia Republic, the upper part of the Pskhu River basin, aspect — SWW, slope — 27°, altitude — 1645 m, cover of tree layer — 70 %, cover of shrub layer — 60 %, cover of herb layer — 12 %, coordinates: 43.4299° N, 40.8661° E, size of plot — 100 m2, Date: 28.07.2019, Authors: N. B. Ermakov and V. D. Leiba).
The alliance Thlaspio macrophylli–Fagion orientalis Ermakov all. nov. includes rich in species beech forests growing preliminarily on calcareous bedrocks in ultra-humid climate of the Western Caucasus (Colchis, Abkhasia). They occupy mountain slopes of different aspects at altitudes of 150–1800 m. Diagnostic species of the alliance are Acer laetum, A. pseudoplatanus, Aristolochia iberica, Asarum intermedium, Dryopteris caucasica, Galeobdolon luteum, Geranium gracile, Hedera colchica, Phyllitis scolopendrium, Polystichum aculeatum, Potentilla micrantha, Sambucus nigra, Symphytum grandiflorum, Thlaspi macrophyllum, Tilia begoniifolia, Ulmus glabra, Vicia crocea. Nomenclature type (holotypus) of the Thlaspio macrophylli–Fagion orientalis is the association Thlaspio macrophylli–Fagetum orientalis Ermakov ass. nov. (described in this paper) — relevés 1–43 in Table 2; syntaxa 1–4 in Table 3. Diagnostic species of the association are the same as for the alliance Thlaspio macrophylli–Fagion orientalis. Nomenclature type (holotypus) of the Thlaspio macrophylli–Fagetum orientalis Ermakov ass. nov. is relevé 12 in Table 2 (field relevé nr. — 103NE19, Abkhasia Republic, near Pskhu village, 2 km S, aspect — N, slope — 12°, altitude — 775 m, cover of tree layer — 60 %, cover of shrub layer — 20 %, cover of herb layer — 65 %, coordinates: 43.3614° N, 40.8035° E, plot size — 100 m2, Date: 26.07.2019, Authors: N. B. Ermakov and V. D. Leiba). This association represents beech forests occupying steep and moderately steep (15–40°) mountain slopes of western, eastern and partly southern aspects at altitudes 1690–1800 m. The association Thlaspio macrophylli–Fagetum orientalis includes four variants — var. typica, var. Asarum intermedium, var. Hypericum xylosteifolium, var. Polystichum setiferum. The association Senecioni jacquiniani–Fagetum orientalis Ermakov ass. nov. includes beech forests occurring in the upper part of forest belt in the Gagrskiy Ridge at altitudes of 1100–1600 m. Diagnostic species: Calamintha grandiflora, Campanula rapunculoides, Fragaria vesca, Hordelymus europaeus, Polygonatum glaberrimum, Senecio jacquinianus, Solidago virgaurea). Nomenclature type (holotypus) is relevé 49 in table 2 (field relevé nr. — 22NE20, Abkhasia Republic, Gagrskiy Ridge, Momzyshkha mountain, middle part, aspect — W, slope — 15°, altitude — 1125 m, cover of tree layer — 60 %, cover of shrub layer — 20 %, cover of herb layer — 70 %, coordinates: 43.2857° N, 40.3209° E, plot size — 100 m2, Date: 24.08.2020, Authors: N. B. Ermakov and V. D. Leiba). The alliance Thlaspio macrophylli–Fagion orientalis includes also the association Sambuco nigrae–Fagetum orientalis Frantsuzov 2006 from the North-Western Caucasus.
The alliance Acero heldreichii–Fagion orientalis Ermakov all. nov. represents the beech forests occurring in the upper part of the forest and subalpine belts of the Caucasus on acidic and calcareous bedrocks at altitudes of 1600–1850 m. Diagnostic species of the alliance are subalpine species (including a large number of the Caucasian endemic tall-forb plants): Acer heldreichii subsp. trautvetteri, Abies nordmanniana, Adenostyles platyphylloides, Aconitum orientale, Agasyllis latifolia, Astrantia major, Asyneuma campanuloides, Calamagrostis arundinacea, Cicerbita petiolata, C. pontica, Dolichorrhiza correvoniana, Dryopteris caucasica, Euphorbia macroceras, Gentiana schistocalyx, Kemulariella caucasica, Lonicera orientalis, Petasites albus, Polygonatum verticillatum, Ptarmica biserrata, Ranunculus cappadocicus, Solidago virgaurea, Valeriana tiliifolia, Woronowia speciosa. Nomenclature type (holotypus) of this alliance is the association Acero heldreichii–Fagetum orientalis Ermakov ass. nov. (described in this paper) — relevés 43–59 in Table 1; syntaxa 19–20 in Table 3. Nomenclature type (holotypus) of the association Acero heldreichii–Fagetum orientalis Ermakov ass. nov. is relevé 54 in Table 1 (field relevé nr. — 47NE20, Abkhasia Republic, Gagrskiy Ridge, Momzyshkha mountain, upper part, aspect — W, slope — 30°, altitude — 1740 m, cover of tree layer — 65 %, cover of shrub layer — 18 %, cover of herb layer — 60 %, coordinates: 43.3138° N, 40.3469° E, plot size — 100 m2, Date: 28.08.2020, Authors: N. B. Ermakov and V. D. Leiba). This association occurs in the upper part of the forest and subalpine belts of the Gagrskiy Ridge (Abkhasia Republic) at altitudes of 1690–1800 m. It includes 2 subassociations — A. t.–F. o. typicum Ermakov subass. nov. and A. t.–F. o. vaccinietosum arctoctaphyli Ermakov subass. nov. At present the alliance Acero heldreichii–Fagion orientalis includes also 3 associations described by Passarge (1980) from the Central Caucasus — Petasito–Fagetum orientalis Passarge 1981, Veratro–Fagetum orientalis Passarge 1981 and Pyrolo–Fagetum orientalis Passarge 1981.
Mountain tundra meadows with dominance of Molinia caerulea were found in the Khibiny Mountains (Kola Peninsula) (Fig. 1) and described based on the Braun-Blanquet approach. Ass. Molinio ...caeruleae–Trollietum europaei ass. nov. (Fig. 2, Table, holotypus — relevé 7, 67.611327° N, 33.61316° E; 530 m a. s. l.) is ascribed to the alliance Potentillo–Polygonion vivipari Nordh. 1937, order Epilobio lactiflori–Geranietalia sylvatici Michl, Dengler et Huck 2010, and class Mulgedio-Aconitetea Hadač et Klika in Klika et Hadač 1944. The diagnostic species are Achillea apiculata, Dianthus superbus, Festuca ovina, Geranium sylvaticum, Melica nutans, Molinia caerulea, Trollius europaeus, Vaccinium myrtillus. The undergrowth layer is sparse and composed with Betula nana, Cotoneaster cinnabarinus, Juniperus sibirica. In the upper layer (about 0.5–0.8 m high) most abundant are tall herbs (Molinia caerulea, Dianthus superbus, Geranium sylvaticum, Trollius europaeus and Cirsium heterophyllum). Lower layer (0.1–0.3 m high) is composed with low herbs (Anthoxanthum alpinum, Bistorta vivipara, Epilobium lactiflorum, E. hornemannii, Festuca ovina, Veronica alpina, Viola biflora, V. canina subsp. montana) and dwarf shrubs (Empetrum hermaphroditum, V. uliginosum, V. myrtillus). Ground layer is prostrate and consists of Sciuro-hypnum starkei, S. reflexum, Sanionia uncinata, Bryum spp. and Polytrichum spp.
Association comunities occupy rather large areas and are located above the tree line and in the lower part of the mountain-tundra belt, at 410–540 m a. s. l., on well-moistened steep (45–50°) rocky slopes, exposed to southwest and southeast, near groundwater outlets or in places of late snowmelt. Probably the association is of relic nature and marks the tree line of the warmest Holocene period. Rich of species, including Red Data Book Cotoneaster cinnabarinus, Epilobium lactiflorum, Veronica fruticans, it is a value habitat type «E2.3 Mountain hay meadow» in the Kola Peninsula.
The fjell field belt is located in mountains of temperate, boreal and arctic zones above the belts with closed vegetation. The environment of the fjell fields is formed due to severe microclimate and ...short growing season, thin soil layer and snow-free conditions in winter (Tolmachev, 1948). The main feature of fjell field landscape is the sparse plant cover dominated by mosses and lichens. The vegetation of fjell fields is still poorly investigated: some geobotanical relevés are available for Scandinavian Mountains (Nordhagen, 1928, 1943; Gjaerevoll, 1950, 1956), West Greenland (Sieg, Daniëls, 2005; Sieg et al., 2006, 2009; Sieg, Drees, 2007), Spitsbergen (Hadač, 1946, 1989; Eurola, 1968; Möller, 2000), and Putorana Plateau (Matveyeva, 2002). The Khibiny and Lovozero Mountains rise up to 1200 m. The vegetation of higher elevations from 840 to 1200 m was classified according to Braun-Blanquet approach in 2013–2021. Based on 90 relevés, 8 associations (5 as new ones), 2 variants and 1 community type were described (Tables 1–8) which belong to 6 alliances, 6 orders, and 6 classes. To arrange the syntaxa described in Khibiny and Lovozero Mountains in higher classification units correctly, we used the first descriptions of alliances in Fennoscandia (62 relevés) and published data of sparse vegetation in fjell fields in Spitsbergen (57 relevés). Among the Spitsbergen data there are 17 relevés of the ass. Sphaerophoro–Racomietum lanuginosi (Hadač 1946) Hofmann 1968 (Hadač, 1989: 159, Table 16; Möller, 2000: 103, Table 30), 19 relevés of the ass. Anthelio–Luzuletum arcuatae Nordh. 1928 (Möller, 2000: 100, Table 29), 21 relevés of vegetation of the fjell fields, not attributed by the author to any syntaxon (Eurola, 1968: 16, 22). Fennoscandian data (62 relevés) include 15 relevés of the ass. Oxyrietum digynae Gjaerevoll 1950 of the Saxifrago stellaris–Oxyrion digynae Gjaerevoll 1950 (Gjaerevoll, 1950: 405, Table VI, rel. 1–15), 10 relevés of the ass. Oppositifolietum (Saxifragetum opposifoliae Gjaerevoll 1950) of the Saxifrago oppositifoliae–Oxyrion digynae Gjaerevoll 1950 (Gjaerevoll, 1950: 422–425, Table XIV, rel. 1–10), 10 relevés of Diapensia–Loiseleuria–Empetrum-Soz. (ass. Loiseleurio-Diapensietum Nordh. 1943) of the alliance Loiseleurio-Arctostaphylion Kalliola ex Nordh. 1943 (Kalliola, 1939: 175–179, Table 26, rel. 1–10), 12 relevés of Anthelia–Cesia reiche–Luzula arcuata-Ass. (ass. Anthelio–Luzuletum arcuatae Nordh. 1928) (Nordhagen, 1928: 311, Table, rel. 1–12), 15 relevés of the ass. Salicetum herbaceae borealis (Cassiopo–Salicion herbaceae) (Nordhagen, 1928: 266–267, Table 42, rel. 1–15). In total 209 relevés were analyzed with use the ExStatR program (Novakovskiy, 2016) based on the Non-metric Multidimensional Scaling (NMS), the Sjørensen-Chekanovsky coefficient was used as a measure of similarity/distance. Plant communities of the class Thlaspietea rotundifolii Br.-Bl. et al. 1947, the alliance Luzulion arcuatae Elvebakk 1985 ex Danilova et Koroleva 2022 are most widely distributed in fjell fields in Khibiny and Lovozero Mountains. The alliance was proposed as provisional in Spitsbergen (Elvebakk, 1985). Here we validate the alliance and propose the ass. Saxifrago oppositifoliae–Flavocerarietum nivalis ass. nov. hoc loco as a neotypus (this paper, Table 2, type relevé (neotypus) of association rel. 5 (2D/20)). The alliance Luzulion arcuatae in Khibiny and Lovozero Mountains includes sparse cover stands dominated by lichens and Racomitrium lanuginosum. It is different from snowbed vegetation (Salicetea herbaceae Br.-Bl. 1948) due to the high number of chionophobous lichens, and from lichen–dwarf shrub communities of the alliance Loiseleurio-Arctostaphylion due to the absence or low number of its diagnostic species (Arctous alpina, Diapensia lapponica, Loiseleuria procumbens). Its communities occur in fjell fields in Spitsbergen, Scandinavian Mountains and in Khibiny and Lovozero Mountains, where two below association were described. Ass. Saxifrago oppositifoliae–Flavocetrarietum nivalis ass. nov. (Fig. 2, Table 2 and 8), nomenclature type (holotypus) — rel. 5 (2D/20); 67.6081° N, 33.7783° E, 08.07.2020; 1010 m. Diagnostic species: Alectoria ochroleuca (d), Flavocetraria nivalis (d), F. cucullata, Racomitrium lanuginosum (d), Saxifraga oppositifolia. Two variants are described — typica (Table 2, rel. 1–9) and Carex bigelowii (Table 2, rel. 10–16). Ass. Сetrariello delisei–Racomitrietum lanuginosi ass. nov. (Table 3 and 8), nomenclature type (holotypus) — rel. 2 (83a/19); 67.6116° N, 33.7610°E; 1010 m. Diagnostic species: Cetraria ericetorum, Pseudephebe pubescens, Racomitrium lanuginosum (д), Rhizocarpon geographicum, Umbilicaria cylindrica, U. hyperborea, U. proboscidea. Class Salicetea herbaceae (the alliance Cassiopo–Salicion herbaceae) includes two associations, which are very similar with associations of the alliance Luzulion arcuatae. Ass. Anthelio–Luzuletum arcuatae Nordh. 1928 (Fig. 3, Table 4 and 8). Diagnostic species: Anthelia juratzkana, Harrimanella hypnoides, Gymnomitrion concinnatum (d), G. corallioides, Marsupella apiculata, Micarea incrassata, Ochrolechia frigida, Pseudolophozia sudetica. Аss. Cetrariello delisei–Harrimanelletum hypnoidis ass. nov. (Table 5 and 8), nomenclature type (holotypus) — rel. 2 (11/14), 67.6644° N, 33.5433° E, 1000 m. Diagnostic species: Andreaea rupestris, Carex bigelowii, Cetrariella delisei, Gymnomitrion concinnatum, Harrimanella hypnoides, Huperzia arctica, Hymenoloma crispulum, Marsupella apiculata. Cryptogamic vegetation in fjell fields is classified into two classes: Rhizocarpetea geographici Wirth 1972 (the alliance Rhizocarpion alpicolae Frey ex Klement 1955) and Racomitrietea heterostichi Neumayr 1971 (the alliance Andreaeion petrophilae Smarda 1944). In the first class, the community type Rhizocarpon geographicum includes combination of epilithic lichen synusia (Rhizocarpon geographicum, Umbilicaria cylindrica, U. hyperborea, U. proboscidea, Pseudephebe pubescens, P. minuscula, Stereocaulon vesuvianum). Within the class Racomitrietea heterostichi Neumayr 1971 ass. Andreaeo rupestris–Racomitrietum microcarpi ass. nov. (Fig. 1, Table 1 and 8) is described. Nomenclature type (holotypus) — rel. 6 (83d/19); 67.6116° N, 33.7610° E, 1000 m. Diagnostic species: Andreaea rupestris, Bucklandiella microcarpa (d). Class Loiseleurio procumbentis–Vaccinietea (the alliance Loiseleurio-Arctostaphylion) includes two associations. Ass. Racomitrio lanuginosi–Dryadetum octopetalae Telyatnikov 2010 (Table 6 and 8). Diagnostic species: Antennaria dioica, Dryas octopetala, Festuсa ovina, Vaccinium vitis-idaea subsp. minus. Ass. Flavocetrario nivalis–Caricetum bigelowii ass. nov. (Fig. 5, Table 7 and 8), nomenclature type (holotypus) — rel. 5 (15b/14), 67.7403° N, 34.7260° E, 900 m. Diagnostic species: Carex bigelowii, Juncus trifidus, Salix polaris, Sphenolobus minutus. There are no conditions for mires in Khibiny and Lovozero Mountains. The only minerotrophic mire described in the narrow damp hollow belongs to the ass. Drepanoclado–Ranunculetum hyperborei Hadač 1989, the class Scheuchzerio palustris–Caricetea fuscae Tx. 1937, the alliance Drepanocladion exannulati Krajina 1933. Diagnostic species: Ranunculus hyperboreus, Warnstorfia exannulata, W. sarmentosa. There are 70 species in vascular plant flora of fjell fields. The ratio of biogeographic elements (Koroleva et al., 2021) is as follows: arctic fraction — 63 %, hypoarctic one — 23 %, boreal one — 4 % and polyzonal one — 10 %, that corresponds to the flora of the arctic type. The ordination shows syntaxonomical continuum due to the absence of boundaries between associations (Fig. 5, 6). The main variation of vegetation is associated with species richness, which is connected with snow cover thickness and duration of the growing season. Community proximity of the alliance Luzulion arcuatae in the Kola Peninsula and Spitsbergen is confirmed on the ordination diagram (Fig. 6), as well as the isolated position of this alliance from Saxifrago stellaris–Oxyrion digynae, and Saxifrago oppositifoliae–Oxyrion digynae. The alliance Luzulion arcuatae is not a synonym of Saxifrago stellaris–Oxyrion digynae. The proximity of Luzulion arcuatae and Loiseleurio-Arctostaphylion is due to synusiae of lichens (Alectoria nigricans, A. ochroleuca, Flavocetraria cucullata, F. nivalis, and Thamnolia vermicularis) dominated in communities of both alliances. The proximityity of Luzulion arcuatae and Cassiopo–Salicion herbaceae is due to the dominance of liverwort (Gymnomitrion concinnatum, Marsupella apiculata, Pseudolophozia sudetica, etc.) synusiae and moss Harrimanella hypnoides.
The steppe zone covers the southern part of Chelyabinsk Region (38 % of territory). Arable land occupies the main part of the steppe zone, virgin steppes form small scattered patches under grazing ...and regular fires. Until now there was no enough information on the diversity of steppe vegetation in this region, whereas the steppe syntaxonomy of adjacent regions is rather well developed (Zhirnova, Saitov, 1993; Dubravnaya ..., 1994; Flora..., 2010; Korolyuk, 2014, 2017; Unikalnye..., 2014; Yusupova, Yamalov, 2016; Yusupova et al., 2018; Golovanov et al., 2021). The purpose of present study is to reveal the diversity of the steppes in the Southern Trans-Urals within the steppe zone and to present their classification according to Braun-Blanquet approach.
The investigated area is a high foothill plain, settling on the Trans-Urals peneplain. Its western border frames the foot of the Urals eastern ridges, and the eastern one adjoins the western limit of marine tertiary sediments of the West Siberian Plain. Igneous, sedimentary and metamorphic rocks of the Paleozoic prevail in geological structure, granite intrusions are widespread. Dominant soils are typical, southern and saline chernozem. The steppe zone forms latitudinal stripe of 2 degrees wide with its northern border along 54 10’ N. From the north to the south the climate becomes warmer and drier. A peculiarity of this area are numerous tiny pine, birch and aspen-birch forests forming a landscape of “false forest-steppe”.
The article is based on the analysis of 286 geobotanical relevés made by authors in 2006–2021 in the southern part of Chelyabinsk Region. The classification was carried out using a modified TWINSPAN algorithm (Roleček et al., 2009) in the JUICE 7.0 package (Tichý, 2002). There are 7 associations, 1 subassociations, 5 variants and 1 community, belonging to orders Brachypodietalia pinnati (meadow steppes) and Helictotricho-Stipetalia (typical steppes) within the class Festuco-Brometea. Associations Artemisio nitrosae–Festucetum valesiacae ass. nov. and Carici supinae–Aizopsietum hybridae ass. nov., subass. Diantho acicularis–Orostachyetum spinosae inops subass. nov. and community Nepeta ucranica–Stipa lessingiana, as well as 5 variants were described for the first time. Ass. Diantho acicularis–Orostachyetum spinosae Schubert, Jäger et Mahn ex Yamalov, Zolotareva, Korolyuk, Makunina, Lebedeva ass. nov. and subass. Poo angustifoliae–Stipetum pennatae Yamalov, Bayanov, Muldashev et Averinova 2013 typicum subass. nov. were validated. Most of syntaxa forming the basis of steppe vegetation belong to the order Helictotricho-Stipetalia.
The zonal herb-bunchgrass steppes of the ass. Helictotricho desertorum–Stipetum rubentis occur on flat surfaces (placors) and gentle slopes, prevailing on hilly plain. Previuosly the such steppes dominated in the northern part of the steppe zone in the West Siberian Plain and Northern Kazakhstan, but now most of these have been replaced by arable land. The unplowed steppes which are strongly used as pastures now are assigned to the ass. Artemisio austriacae–Stipetum capillatae.
Meadow steppes of the order Brachypodietalia pinnati are strictly related to the “false forest-steppe” landscape. In the steppe zone meadow steppes of the subass. P. a.–S. p. typicum (Fig. 4) occur at the edges of forests and in shallow depressions. Further north, in the forest-steppe zone of the Trans-Urals, this subassociation becomes typical. The mostly mesophytic meadow steppes of the “false forest-steppe” stripe belong to the subass. Galio veri–Stipetum tirsae serratuletosum coronatae.
The main factors responsinle for differentiation of vegetation of the class Festuco-Brometea in study area are moisture, salinity and rock outcrops.
The topological series along the moisture gradient is represented in the landscape of “false forest-steppe”: Galio veri–Stipetum tirsae serratuletosum coronatae (meadow steppes on the edges of forests) → Poo angustifoliae–Stipetum pennatae typicum (meadow steppes on the edges of forests and in shallow depressions) → Helictotricho desertorum–Stipetum rubentis (common herb-bunchgrass steppes).
Numerous rock outcrops in the central part of the Urals are the reason for the wide distribution of petrophytic communities. However, the diversity and species richness of petrophytic steppes is small (only two associations) in the Trans-Urals peneplain where rough-skeletal and eroded soils are rare. Petrophytic steppes of the ass. Carici supinae–Aizopsietum hybridae ass. nov. (Table 11, rel. 1–12), holotypus: Table 11, rel. no. 4 (12-0173): Russian Federation, Chelyabinsk Region, Chesmenskiy district, mountain Shchukina near Kalinovskiy settlement, 53.81199° N, 60.50121° E, 12.06.2012, collector — A. Yu. Korolyuk) are common on granite outcrops in the most elevated relief elements of the Urals-Tobolsk watershed. Communities of the subass. Diantho acicularis–Orostachyetum spinosae inops subass. nov. (Table 10, rel. 1–12), holotypus: Table 10, rel. no. 11 (12-0139): Russian Federation, Chelyabinsk Region, Kartalinskiy district, right bank the river Karagaylyayat between the v. Varshavskay and Elizavethopolskoe, 52.81884° N, 60.45562° E, 09.06.2012, collector — A. Yu. Korolyuk) on the various rock outcrops are the impoverished variant of petrophytic steppes of the mountainous part of the Urals.
The communities of the ass. Artemisio nitrosae–Festucetum valesiacae ass. nov. (Table 8, rel. 1–12. Holotypus hoc loco: Table 8, rel. no. 3 (12-0128): Russian Federation, Chelyabinsk Region, Bredinskiy district, near Bredy settlement, 52.44794° N, 60.32095° E, 08.06.2012, collector — A. Yu. Korolyuk) occur on the slopes with saline tertiary clays in the eastern part of study area.
The steppes of the Southern Trans-Urals combine the characteristic features of the steppe vegetation of adjacent territories. Herb-bunchgrass steppes in the Southern Trans-Urals are closely related to the West Siberian and Kazakhstan ones, while meadow steppes are associated with the Southern Urals syntaxa; the last ones include a number of European meadow-steppe species. There are some Urals endemics in syntaxa of petrophytic steppes, that make them closer to the Southern Urals syntaxa.
The highest reed (Phragmites altissimus) is a species with Eurasian-North African range, recently expanding its area of distribution in northern direction (Kapitonova, 2016; Golovanov et al., 2019; ...Tzvelev, Probatova, 2019). It is known that in the forest zone of both the European and Asian parts of Russia, the highest reed is found only as an invasive plant (Tzvelev, 2011). Communities dominated by P. altissimus are known both within its natural range and in the area of invasion. However, in syntaxonomic reviews, cenoses with this species dominanation are traditionally included by the authors in the ass. Phragmitetum australis Savich 1926 (Golub et al., 1991, 2015; Golub, Chorbadze, 1995; Kipriyanova, 2008; Vegetaсе…, 2011; Golovanov, Abramova, 2012; Chepinoga, 2015). The aim of this work is to establish the syntaxonomic status of communities formed by P. altissimus.
The work used 65 geobotanical relevés made within the primary range of the P. altissimus (Astrakhan region and the south of the Tyumen region within the forest-steppe zone) and in the area of its secondary range (the Udmurtian Republic and the taiga zone of the Tyumen region). The relevés were introduced into database developed on the basis of the TURBOVEG program (Hennekens, 1996) and processed using the JUICE program (Tichý, 2002). To assess the abundance of species on the sample plots described, the J. Braun-Blanquet abundance scale was used with the following abundance-coverage scores: r — the species is extremely rare with insignificant coverage, + — the species is rare, the degree of coverage is small, 1 — the number of individuals is large, the degree of coverage is small or the individuals are sparse, but the coverage is large, 2 — the number of individuals is large, the projective cover is from 5 to 25 %, 3 — the number of individuals is any, the projective cover is from 25 to 50 %, 4 — the number of individuals is any, the projective cover is from 50 to 75 %, the number of individuals is any, the cover is more than 75 % (Mirkin et al., 1989). Syntaxonomic analysis was performed using the approach suggested by J. Braun-Blanquet (1964). The names of syntaxa are given according to the “International Code of Phytosociological Nomenclature” (Theurillat et al., 2021). The system of higher syntaxa is given in accordance with “Hierarchical floristic classification…” (Mucina et al., 2016). To identify the main factors determining the differentiation and distribution of the studied communities, the NMDS method was used. For each syntaxon, using the IBIS program (Zverev, 2007), the average indicator values were calculated according to the ecological scales of D. N. Tsyganov (Tsyganov, 1983): soil moisture (Hd), soil nitrogen richness (Nt), and illumination-shading (Lc). Processing was carried out in the PC-ORD v. 6.0 (McCune et Mefford, 2011).
The studied communities were assigned to the new ass. Phragmitetum altissimi, 4 subassociations, and 7 variants.
The nomenclature type of association is relevé N 20 in Table 3. It is shown that in the communities of the ass. Phragmitetum altissimi, the number of species ranges from 1 to 15 (in average 4). The total projective cover varies from 20 to 100 %. The height of the herbage is 2–5 m; four to five substages are distinguished in it. In the first substage, in addition to P. altissimus, the presence of large cattails (Typha austro-orientalis, T. linnaei, T. latifolia, T. tichomirovii), as well as tall grasses (Calamagrostis pseudophragmites, Phalaroides arundinacea) and Scirpus hippolyti was recorded. The second substage is formed by grasses of medium height (up to 0.8–1 m): Carex riparia, Sparganium erectum, Oenanthe aquatica, Stachys palustris, Lythrum salicaria, Althaea officinalis, Persicaria maculata, P. minor, Cirsium setosum, much less often — Impatiens glandulifera, Urtica dioica, etc. The third substage is not always developed, as a rule, it is very sparse, formed by surface hygrophilic grasses usually no more than 10–20 (25) cm in height (Rorippa amphibia, Galium palustre, Potentilla reptans, Tussilago farfara). The fourth substage is usually sparse; it is formed by rooting (Nymphaea alba) or non-rooting (Salvinia natans, Lemna minor, L. turionifera, Spirodela polyrhiza, Hydrocharis morsus-ranae) hydrophytes floating on the water surface. The fifth substage is formed by non-rooting hydrophytes completely submerged in water (Lemna trisulca, Ceratophyllum demersum), as well as Drepanocladus aduncus and Cladophora sp. Often are out-of-tier vinegrasses (Calystegia sepium, Cynanchum acutum); sprouts of willows (Salix cinerea, S. alba) are also quite common.
Communities dominated by P. altissimus are formed in coastal shallow waters, including swampy, stagnant or weakly flowing water bodies with stable or slightly fluctuating water level, with tight bottom or small, sometimes quite thick layer of silty-detrital deposits. Communities also are formed on damp or swampy shores, including disturbed, permanent or temporarily drying water bodies. In anthropogenic habitats, they are developed in watered and damp depressions (ditches), in shallow waters and damp banks of ponds, reservoirs, man-made water bodies, excavations, and watered quarries. Cenoses of the subass. P. a. typicum (Fig. 2) are formed on coastal shallow waters and damp shores of permanent or temporarily drying water bodies, including disturbed ones. Communities of the subass. P. a. caricetosum ripariae are characteristic of swampy coastal areas and swampy shores of water bodies with stable or slightly fluctuating water level; they are distinguished by sparse and relatively low upper substage of the herbage composed of P. altissimus. Communities of the subass. P. a. phalaroidetosum arundinaceae, which occcur in coastal shallow waters (up to 5–10 cm deep) and damp shores of water bodies, are characterized by rather dense upper substage of herbage and temporary drying of the substrate during the growing season. Communities of the subass. P. a. lemnetosum trisulcae are formed in water bodies, the water level in which is subject to fluctuations during the growing season; they are characterized by dense substage of grasses submerged in water and significant thickness of silty bottom sediments..
Communities of the ass. Phragmitetum altissimi are distributed within the primary range of P. altissimus — in the south of the European part of Russia (Astrakhan region) and in the forest-steppe zone of Western Siberia (Tyumen region). They are also found in the area of invasion of the highest reed — in the east of the Russian Plain (Udmurtian Republic), in the taiga zone of Western Siberia (Tyumen region) (Fig. 1). In the secondary range of the highest reed, only cenoses attributed to the subass. P. a. typicum are recorded. Communities belonging to all four subassociations are widespread within the primary range of P. altissimus on the territory of the European part of Russia.
The information on the syntaxonomic diversity of aquatic vegetation in the Ob-Irtysh interfluve (south of West Siberia), which was revealed using the ecological-floristic approach (Braun-Blanquet, ...1964) is summarized. Lake ecosystems of the studied region are exposed to cyclical changes in accordance with the cyclicity of the hydrological regime of the lakes. Periodic fluctuations in the water level in lakes are accompanied by changes in mineralization, and therefore the biological regime of the lakes is unstable. The studies were carried out from 2001 to 2014 in Novosibirsk Region and Altai Territory. 164 complete geobotanical relevés made by the author on 80 lakes are used (Fig. 1, table 1); a list of studied lakes is given.
Field work was carried out during the period of the lowest water level (summer dry season) — July–August. The following scale was used for abundance estimation: r — the species is extremely rare; + — rare, small cover; 1 — the number of individuals is large, the cover is small or individuals are sparse, but the cover is large; 2 —cover of 5–25 %; 3 — 26–50 %; 4 — 51–75 %; 5 — more than 75 %. Computer programs Turboveg for Windows 2.117 (Hennekens, Schaminée, 2001) and Juice 7.0.45 (Tichý, 2002) were used for data treatment. The syntaxonomic affiliation of phytocenoses was determined using modern literature (Bobrov, Chemeris, 2006; Vegetace…, 2011; Chepinoga, 2015; Landucci et al. 2015; Mucina, 2016).
The coenotic diversity of aquatic vegetation in the studied lakes is 43 associations and 2 communities from 12 alliances, 6 orders, 5 classes (Tables 2–11). Eight associations belong to the class Lemnetea; 18 associations — Potamogetonetea; 3 associations and 2 communities — Stigeoclonietea tenuis; 9 associations — Charetea intermediae; 5 associations — Ruppietea maritimae. This rather high value of phytocenotic diversity is due to the high diversity of ecological conditions of specific lakes, in turn, determined by the different origin of lakes, the nature and composition of soils, salinity and chemical composition of waters, and temperature regime. Two new associations – Najadetum majoris ass. nov. and Ranunculetum subrigidi ass. nov. — are described.
Table 10 shows the values of the frequency of associations (aquatic communities) in the lakes of the Novosibirsk region.
We have identified phytocenotic complexes on the basis of data on the ranges of halotolerance of associations and in accordance with the frequency of associations in the lakes of different mineralization. Four phytocenotic complexes can be distinguished for the studied lakes of the Baraba Lowland and Kulunda Plain: freshwater, oligo-mesohaline, meso-hyperhaline, and euryhaline (Fig. 12).
As for the ranges of halotoleration of lake communities, it is obvious that it is impossible to establish the universal ranges of halotolerance of species and communities of macrophytes for a number of reasons 1) regional differences in the salt composition of waters, 2) seasonal fluctuations in water salinity; 3) varying methods of mineralization measuring (ionometrically or analytically and also different analytical methods — by the sum of ions, and by the dry residual). However, several general trends can be distinguished. The main trend is a decrease in the species and coenotic diversity of aquatic and semi-aquatic vegetation with mineralization growth (Hammer, 1988; Williams, 1998; our data, etc.) This universal pattern is true for all groups of biota (Hammer, 1986; Williams, 1998; Kipriyanova et al., 2007, etc.). Communities of the assosiations Lemnetum trisulcae, Lemno–Utricularietum vulgaris, Potamogetono–Ceratophylletumsubmersi, Najadetum marinae, Potamogetonetum perfoliati were more resistant to high mineralization (up to 5 g/dm3 according to our data). The highest halotolerance among aquatic plant communities is found for the associations Ruppietum maritimae and Ruppietum drepanensis, as well as for Cladophoretum fractae.
Based on the results of our research, it has been shown that in the continental lakes of the southeast of Western Siberia, such specific cenoses of continental water bodies of Siberia, as the communities of the assosiations Stuckenietum macrocarpae and Cladophoro fractae–Stuckenietum chakassiensis (Kipriyanova, 2017), mainly occur in oligo- and mesohaline waters in the range of mineralization 0.5–18.0 g/dm3.
Stratiotetum aloidis, Nymphaeo–Nupharetum luteae, Nymphaeetum candidae associations were common in the freshwater lakes (up to 0.5 g/dm3), another ones were met moderately and less frequently. Associations Lemnetum trisulcae, Lemno minoris Ceratophylletum demersi were common in the β-oligohaline (0.5–1 g/dm3) lakes. Lemno–Utricularietum vulgaris, Myriophylletum sibirici, Potamogetonetum pectinati, Potamogetonetum perfoliati, Stuckenietum macrocarpae were moderately frequent, the rest were rare and solitary. Associations Lemnetum trisulcae, Lemno minoris–Ceratophylletum submersi, Stuckenietum macrocarpae, and Cladophoro fractae–Stuckenietum chakassiensis were common in the α-oligohaline lakes (1–5 g/dm3). The rest were moderately and less frequent. In mesohaline waters (5–18 g/dm3), associations Cladophoro fractae–Stuckenietum chakassiensis and Ruppietum maritimae were common. The rare in the studied lakes communities of the associations Najadetum marinae, Ruppietum maritimae, Ruppietum drepanensis, Charetum tomentosae, Nitellopsidetum obtusae are need in protection, since they include the species listed in the Red Data Book of the Novosibirsk Region (Krasnaya ..., 2018).
According to the Braun-Blanquet approach the segetal communities of rice agrocenoses of Eurasia belong to the class Oryzetea sativae Miyawaki 1960, although there is a lot of species that are ...diagnostic of different classes — Phragmito-Magnocaricetea Klika in Klika et Novák 1941, Lemnetea O. de Bolòs et Masclans 1955, Potamogetonetea Klika in Klika et Novák 1941, Bidentetea Tx. et al. ex von Rochow 1951, etc. The largest number of the described basic syntaxa (associations, subassociations or communities) are allocated in Eastern, South-Eastern and Central Asia. Lots of new syntaxa specific to the rice fields were described in Japan (Miyawaki, 1960), Southern Thailand (Nowak et al., 2015), Central Nepal (Nowak et al., 2016), North Korea (Kolbek et al., 1996; Kolbek, Jarolímek, 2013), Tajikistan (Nowak et al., 2013), Vietnam and the Philippines (Fried et al., 2017, 2018), many of which have been assigned in the alliance Ludwigion hyssopifolio-octovalvis A. Nowak, S. Nowak, Nobis 2015, the order Cypero–Echinochloetalia oryzoidis O. de Bolòs et Masclans 1955, the class Oryzetea sativae. The rice communities described in Western (Spain, Portugal, Andorra, Italy, France, Hungary, Romania, Bulgaria) and Eastern (Ukraine, Russian Federation) Europe which differ in species composition from those in Asian regions are assigned to the alliance Oryzo sativae–Echinochloion oryzoidis O. de Bolòs et Masclans 1955 within the above order and class.
The paper represents the first results of the classification based on 20 relevés of rice communities studied in 2018 in the Gudermessky and Shelkovskoy districts of the Chechen Republic, located on the northern slope of the Great Caucasian Ridge, the Chechen Plain and the Terek–Kuma Lowland. The areas under rice crop rotation are kept at an altitude of 20–35 m above sea level both in the north and in the plain part, mainly in the interfluves of the Terek and Sunzha rivers. The climate in the rice-growing areas is continental, insufficiently humid, with the very warm summers and moderately mild winters and the lot of heat and dryness in the summer months. The mean year temperature is 10.8 °C, during the growing season of rice (May–September) — 20.8 °C; the sum of effective temperatures above 15 °C is about 3100–3400 °C (Tulyakova, 1973; Ryzhykov et al., 1991); the annual amount of precipitation is 400—450 mm with less than 270 mm in summers. The largest areas on the Terek and Sunzha river interfluve are occupied by intrazonal meadow and swamp vegetation.
There are two associations and one community belonging to the alliannce Oryzo sativae–Echinochloion oryzoidis have been established within study area. The associations Echinochloo–Oryzetum sativae Soó ex Ubrizsy 1948 (Table 2, rel. 1–8) and Oryzo–Cyperetum difformis Koch 1954 (Table 2, exp. 9–14) are widely distributed in rice fields in Western and Eastern Europe, while the community Setaria pumila–Oryza sativa (Table, rel. 15–20) is a new one. On cultivated lands, the composition and structure of segetal communities depends on the intensity of agrotechnical measures, as well as on the depth and duration of flooding. The species diversity of the communities adjacent to the fields, formed in the discharge channels and on the dams between rice bays, have a significant impact. In the rice fields in the presence of chemical and agrotechnical processing, communities of the ass. Echinochloo–Oryzetum sativae prevail, and the communities of the ass. Oryzo–Cyperetum difformis and Setaria pumila–Oryza sativa are formed where this impact is not strong. The significant participation of Cyperus glomeratus is a distinctive feature of the Chechen Republic segetal communities from the analogous ones compare with the other regions of Europe.
Classification of communities with Heracleum sosnovskyi in the Kursk Region (Table 1), based on 43 relevés, made by the author in 2014–2020 in some locations mainly in the western part of the study ...area (Fig. 1), is carried out according to Braun-Blanquet approach. The data are treated by IBIS 7.2 software package (Zverev, 2007). The names of the higher syntaxa follow to «Vegetation of Europe…» (Mucina et al., 2016). Synoptic tables include only species with constancy above I. Soil moisture, reaction, richness in mineral nitrogen, light, temperature and continentality are assessed using mean H. Ellenberg ecological indicator values (Ellenberg et al. 1992), hemeroby — with these of N. G. Ilminskikh ecological 9-point scale (Ilminskikh, 1993). Significant differences between pairs of syntaxa for each environmental factor are determined by the Mann-Whitney U-test in the PAST package (Hammer et al. 2001). 3 associations, 2 variants and 1 derivative community of 3 classes of vegetation are established. Ass. Chelidonio–Aceretum negundi L. Ishbirdina in L. Ishbirdina et al. 1989, var. Heracleum sosnowskyi (Table 2, Fig. 2). The association belongs to alliance Chelidonio–Acerion negundi L. Ishbirdina et A. Ishbirdin 1989, order Chelidonio–Robinietalia pseudoacaciae Jurco ex Hadač et Sofron 1980, class Robinietea Jurco ex Hadač et Sofron 1980. DS of the association are Acer negundo, Chelidonium majus, that of the variant is Heracleum sosnowskyi. Communities most often have three layers. The tree layer is dominated by Acer negundo with 7–20 m heigh and 50–90 % canopy density. The shrub layer (1–3 m, 1–50 %) is dominated by Acer negundo undergrowth, sometimes there are Padus avium, Populus alba, Prunus domestica, Sambucus nigra, S. racemosa, Ulmus glabra. The herb-dwarf shrub layer (height – 70–150 cm, plant cover – 50–100 %) is dominated by Heracleum sosnowskyi, mainly by its vegetative shoots. Generative shoots are found mainly in the most sunlit sites. There are 68 species in the association with 7–21 species per sample plot. The communities formed as a result of H. sosnowskyi penetration into phytocenoses of the var. typica ass. Chelidonio–Aceretum negundi are common in wastelands, along roads and banks of reservoirs, near abandoned houses in villages. There are slight differences in habitats of variants Heracleum sosnowskyi and typica (Fig. 3, Table 4): communities of the first one inhabit wetter soils, while these of the var. typica have the higher levels of temperature, continentality and hemerobiality, that is why there is a lot annuals and biennials, many of which are continental thermophilic species and belong to eu- and polyhemerobes (Lactuca serriola, Atriplex tatarica, Arctium tomentosumи др.). H. sosnowskyi exists even in heavily shaded areas. The species composition of communities of the var. Heracleum sosnowskyi is quite stable which is facilitated by the flow of seeds from surroundings and the capacity of germination of those seeds that did not germinate in the first year, as well as the ability of specimens to exist in a vegetative state for a long time under unfavorable conditions (Vinogradova et al., 2010; Panasenko, 2017). Ass. Urtico dioicae–Heracleetum sosnowskyi Panasenko et al. 2014 (Table. 5, rel. 1–17, Fig. 4). The association belongs to alliance Aegopodion podagrariae Tx. 1967 nom. conserv. propos., order Circaeo lutetianae–Stachyetalia sylvaticae Passarge 1967 nom. conserv. propos., class Epilobietea angustifolii Tx. et Preising ex von Rochow 1951. DS: Heracleum sosnowskyi, Urtica dioica. The total plant cover is 80–100 %. Communities have three sub-levels: the upper one (1.0–1.5 m) is of Heracleum sosnowskyi generative shoots; the mid one (1–1.5 m) is of its leaves; the lower one is of herbs Anthriscus sylvestris, Arctium tomentosum, Artemisia vulgaris, Ballota nigra, Cirsium arvense, Dactylis glomerata, Elytrigia repens, Galium aparine and Urtica dioica. There are 83 species in the association, with 9–29 species per sample plot. Such communities, formed as a result of Heracleum sosnowskyi invasion into phytocenoses of the class Epilobietea angustifolii, often occur in anthropogenic habitats. Derivative community Heracleum sosnowskyi Agropyretalia intermedio–repentis (Table. 5, rel. 18–25, Fig. 5). DS: Heracleum sosnowskyi. The total plant cover is 85–100 %. Communities have three sub-levels, just like in the previous syntaxon. However, in contrast to it, species of Artemisietea vulgaris Lohmeyer et al. in Tx. ex von Rochow 1951 prevail in the derivative community (Table. 6). Species of order Agropyretalia intermedio–repentis T. Müller et Görs 1969 are represented with high constancy. Such communities, formed as a result of Heracleum sosnowskyi invasion into phytocenoses of this order, occur along roads, in wastelands, on dry meadows. There are 68 species in the community coenoflora, with 7–30 species per sample plot. There are differences in habitats of this derivative community and the ass. Urtico dioicae–Heracleetum sosnowskyi (Fig. 6, Table 7). Communities of the association often inhabit wetter and eutrophic soils, while derivative ones are common in more sunlit and heated sites. Ass. Rudbeckio laciniatae–Solidaginetum canadensis Tüxen et Raabe ex Anioł-Kwiatkowska 1974, var. Heracleum sosnowskyi (Table. 5, rel. 26–31, Fig. 7). The association belongs to alliance Dauco-Melilotion Görs ex Rostański et Gutte 1971, order Onopordetalia acanthii Br.-Bl. et Tx. ex Klika et Hadač 1944, class Artemisietea vulgaris. DS of the association is Solidago сanadensis, this of the variant is Heracleum sosnowskyi. Both are dominating species. The total plant cover is 100 %. Phytocenoses have three sub-levels: the upper one (up to 3 m high) is of H. sosnowskyi generative shoots; the mid one (1.0–1.5 m) is of its leaves (sometimes quite numerous) and of Solidago сanadensis; the lower one (up to 0.5 m high) is of Heracleum sosnowskyi seedlings, as well as of Achillea millefolium, Carex hirta, Equisetum arvense and Poa angustifolia with lower cover. There are 48 species in the association, with 12–18 species per sample plot. Such communities common in the northwestern part of the Kursk region occur in wastelands, along roads and banks of reservoirs. They appeared as a result of Heracleum sosnowskyi penetration into phytocenoses of the ass. Rudbeckio laciniatae–Solidaginetum canadensis (Fig. 8), as well as with concurrent spread of both Heracleum sosnowskyi and Solidago сanadensis on the territory (Fig. 9). In spite of significant differences in soil moisture and temperature, in general, habitats of variants Solidago сanadensis and Heracleum sosnowskyi of the ass. Rudbeckio laciniatae–Solidaginetum canadensis are rather similar (Fig. 10, Table 8). There are fewer xeromesophytes of the order Onopordetalia acanthii and more species of the class Epilobietea angustifolii in the species composition of the var. Heracleum sosnowskyi (Table 9).
The classification of West Siberian mire vegetation is more or less well developed in the southern part of the forest zone (Lapshina, 2010) while in the northern part of the West Siberian Plain it ...has received much less study. There are only a small number of publications containing descriptions of mire types and plant communities (Pyavchenko, 1955; Boch et al., 1971; Kirpotin et al., 1995; Smagin, 2003; Neshatayev et al., 2002).
This paper presents the classification results for the low-sedge vegetation of waterlogged hollows and Sphagnum lawns, within flat palsa-bogs, ombrotrophic raised bogs and transitional mire complexes, which is assigned to two alliances — Stygio–Caricion limosae Nordhagen 1943 and Scheuchzerion palustris Nordhagen ex Tx. 1937 of the class Scheuchzerio–Caricetea nigrae Tx. 1937. The classification is based on 422 relevés performed in 2004–2019 at 22 plots located between 63° and 75° N in the northern taiga, forest tundra, and southern tundra subzones of West Siberia (Fig. 1).
In the most recent summary “Vegetation of Europe…” (Mucina et. al., 2016), the alliance Stygio–Caricion limosae is assigned to the order Sphagno watnstorfii–Tomentypnetalia Lapshina 2010, however this does not seem conclusive. Communities of this order are closely associated with rich fens, often spring fens fed by ground water, which does not correspond to the real conditions in which communities of this alliance are developed. Ecologically, in the current structure of the class Scheuchzetio–Caricetea nigrae (Peterka et al, 2017), the alliance Stygio–Caricion limosae has taken the true place of the alliance Rhynchosporion albae Koch 1926 (ICPN, Art. 36), which was initially unambiguously associated with the order Caricetalia nigrae Koch 1926 based on the original relevés and diagnostic species (Rhynchspora alba, Agrostis canina, sphagnum mosses of sec. Subsecunda). Therefore, we also consider the alliance Stygio–Caricion limosae belonging to the order Caricetalia nigrae, where it fits better judging by its ecological and floristic features.
The differential species combination of the alliance Stygio–Caricion limosae in the northern part of West Siberia includes Carex limosa, Drosera obovata, Juncus stygius, Gymnocolea inflata, Sphagnum perfoliatum, S. platyphyllum, S. subsecundum, Utricularia minor, U. ochroleuca, Warnstorfia exannulata, and W. fluitans.
Within this alliance, two new associations with subassociations have been described: Utricularo ochroleucae–Caricetum limosae and Sphagno perfoliati–Caricetum rotundatae, of which the first one occurs in the northern taiga mires, while the second one in the forest tundra and southern tundra subzones.
The order Scheuchzerietalia palustris Nordhagen ex Tx. 1937 comprises ombrotrophic vegetation of Sphagnum lawns and bog hollows (Mucina et al., 2016) and currently includes the only alliance Scheuchzerion palustris. Its typical boreal suballiance Scheuchzerienion palustris suball. nov. (nomenclature type — lectotypus hoc. loco: ass. Scheuchzerietum palustris Tüxen, 1937: 61) is represented by two associations: Eriophoro vaginati–Sphagnetum baltici and Carici limosae–Sphagnetum jenseni. Their distribution to the north is limited by the mire complexes of the northern taiga. Further north similar habitats are occupied mainly by communities of the predominantly subarctic suballiance Caricion rariflorae. Within this suballiance, two associations — Carici rotundatae–Sphagnetum baltici and Carici rotundatae–Sphagnetum lindbergii — are widely distributed over the entire gradient from the northern taiga to the southern tundra. The ass. Carici rariflorae–Sphagnetum baltici occurs only occasionally and is bound to the forest tundra and southern tundra.
Statistical processing of the entire data set was performed to confirm the classification results and make a number of syntaxonomic decisions. The results of t-SNE ordination (t-distributed stochastic neighbor embedding method) (van der Maaten, Hinton, 2008) confirmed the validity and expediency of separating oligotrophic and mesooligotrophic low-sedge communities of hollows and fens not only at the alliance level, but also at the order level. Despite certain physiognomic and floristic similarities, the location points of the two alliances in multidimensional space are well differentiated and do not overlap with each other (Fig. 10).
Calculation of the floristic similarity degree of relevés with regard to species abundance and visualization of the statistical processing results have clearly demonstrated that the entire relevé array of oligotrophic sphagnum lawns in the alliance Scheuchzerion palustris can be divided by the dominant sphagnum moss species into separate clusters, within which dominant grass layer clusters could also be distinguished.
Given that, in the future, the formal statistical processing of large sets of geobotanical data will become an increasingly important tool to underpin syntaxonomic decisions, this fact cannot be ignored.
In this connection, we propose to review the current practice of identifying associations of mire vegetation by the dominant species of vascular plants and sub-associations by the dominant moss species. The latters are of primary importance in the poor-species plant communities of waterlogged hollows and fens, because they are more sensitive to ecological conditions of habitats, which ultimately determine the entire floristic composition and community structure.
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.
