Communities of the Molinio-Arrhenatheretea class in the Biysk-Chumysh Upland region (Altai Krai)

The article reveals the study of the syntaxonomic diversity of meadow vegetation in the Biysk-Chumysh Upland region (Altai Krai) based on the analysis of 230 complete geobotanical descriptions. The levels of hydration and use (grazing, idle land) are proved to be the main ecological factors. The variety of the Molinio-Arrhenatheretea class in the Biysk-Chumysh Upland (Altai Krai) is represented by three orders. The Molinietalia order is representative of wet meadows, whose floristic composition is mostly comprised of water resistant species. The Arrhenatheretalia order is representative of well-hydrated meadows. The Galietalia veri encompasses the communities of steppe meadows, the cenoflora of which unites the species of true meadows and meadow steppes.


Results
Syntaxonomic analysis of the Molinio-Arrhenatheretea class communities on the territory of the Biysk-Chumysh Upland (Altai Krai) revealed 1 association, 9 rankless communities of 3 orders. The prodromus features the identified units and their position in the system of higher units, according to the prodromus of the Russian vegetation (Ermakov, 2012) (Table 1).

Prodromus of the Molinio-Arrhenatheretea class communities
Class MOLINIO-ARRHENATHERETEA R. Tx. 1937 Order MOLINIETALIA Koch 1926  IV  IV  III  II  IV  I  V  III  II  II   Vicia cracca   V  III  III  .  IV  I  III  III  III  +   Achillea millefolium   II  II  III  I  II  .  II  I  II  II   Phleum pratense   II  IV  III  II  I  II  III  IV  .  I   Galium mollugo   I  +  +  +  III  IV  II  IV  I  II   Leucanthemum vulgare   III  II  +  .  II  .  IV  IV  II  I   Plantago media   II  I  II  III  I  I III  II  III  IV  II  IV  II  II  V 2-3  V   Centaurea scabiosa   I  r  I  I  r  III  III  I  III  V   Galium verum   I  r  .  III  I  .  II  II  IV  IV   Onobrychis arenaria   IV  .  II  II  .  .  II  II I  III  III  II  I  III  III  .  II  +   Achillea asiatica   I  I  II  III  IV  V  II  II  I  II   Linaria vulgaris   II  III  II  II  III  IV  +  III  .  +   Echium vulgare   .  III  III  I  IV  III  V  IV  IV  MOLINIO-ARRHENATHERETEA class Diagnostic species: Achillea millefolium, Agrostis gigantea, Bromopsis inermis, Carum carvi, Dactylis glomerata, Elytrigia repens, Festuca pratensis, Geranium pratense, Lathyrus pratensis, Leucanthemum vulgare, Phleum pratense, Plantago media, Poa pratensis, Ranunculus polyanthemos, Stellaria graminea, Trifolium pratense, Vicia cracca. The Molinio-Arrhenatheretea class encompasses secondary post-forest meadows of the Eurasia temperate zone on relatively rich non-saline soils. Communities are formed as a result of deforestation (broad-leaved, mixed, coniferous forests) with a subsequent mowing or grazing use of the territory. For this reason, the basis of the grassstand is comprised of species adapted to restore phytomass after regular disposal -mowing or grazing. The range of the class covers the whole of Western, Central and Eastern Europe, most of Russia from the western borders to the Far East (Tüxen, Preising, 1951;Dierschke, 1995Dierschke, , 1997Schaminee et al., 1996Ermakov et al., 1999Matuszkiewicz, 1984;Mucina et al., 1993;Korolyuk, Kipriyanova, 1998;Rodwell et al., 2007;Janišova et al., 2007;Vegetace…, 2007;Korolyuk, Makunina, 2000, 2001Makunina, Maltseva, 2003;Lashinskiy, 2009;Averinova, 2010;Yamalov, 2011, etc.). The class communities are well represented in the Transbaikal and Yakutia regions. In the south of the Far East, it is replaced by the East Siberian Far Eastern vicariant classes Calamagrostietea langsdorffii Mirkin in Akhtyamov et al. 1985(Akhtyamov, 1995Anenkhonov, 2003) and Arundinello anomalae -Agrostietea trinii Ermakov et Krestov 2009(Ermakov, Krestov, 2009). In the territory under study, the class is represented by three orders Molinietalia, Arrhenatheretalia, Galietalia veri, which comprise wet, real and steppe meadows respectively.
The order comprises wet meadows, which floristic composition is characterised by the dominance of water resistant species. On the gradient of environmental conditions, on one side, they border on the well-hydrated meadows of the Arrhenatheretalia order, and on the communities of eutrophic high sedge and grass bogs of the Magnocaricetalia order (Phragmiti-Magnocaricetea class) on the other side. Only one community of meadows is assigned to this order in the Potentillion anserinae alliance system.

Potentillion anserinae R. Tx. 1947 alliance
It unites the communities of plants resistant to grazing and trampling, growing on waterlogged soils in the conditions of intensive grazing. It is formed in depressions along the banks of ponds, rivers, and streams on annually flooded habitats (Passarge 1964;Vegatace.., 2007;Grigoryev et al., 2002;Cherosov et al., 2005).
It comprises communities with intensive grazing use. They are common for low habitats with moderate soil moistening in the Kosikhinskiy district. The projective cover of the grassstand varies from 55 to 75%. Despite the anthropogenic load, the species range of the communities remains rather high and averages 19 species per 100 m 2 . The height of the grassstand is 65 cm on average.

Communities of the Molinio-Arrhenatheretea class
Ukrainian Journal of Ecology, 10(5), 2020 The group of the Molinio-Arrhenatheretea class meadow species (Dactylis glomerata, Stellaria graminea, Trifolium pratense, Phleum pratense) is encountered with high constancy. The proportion of species of the Trifolio-Geranietea class forest edge and woodland communities (Agrimonia pilosa, Hypericum perforatum, Origanum vulgare, Veronica chamaedrys) is not high. A noticeable part of the grass stand is a group of synanthropic herbaceous species of the Artemisietea vulgaris class (Berteroa incana, Echium vulgare, Arctium tomentosum, Artemisia sieversiana, etc.). A significant role in the floristic composition belongs to species of the Polygono arenastri-Poetea annuae class that withstand trampling and high pasture load -Amoria repens, Taraxacum officinale. When trampling is reduced or stopped, meadow species of the Molinio-Arrhenatheretea class insinuate into the community.
It differs from other communities in a more mesophytic composition and a higher proportion of meadow species, which indicates the formation of natural vegetation, but pasture load blocks restoration.

ARRHENATHERETALIA order
Diagnostic species of the order = diagnostic species of the class. The order is characteristic of the well-hydrated meadows in the temperate zone of Eurasia. The grass stand is based on typical mesophytes that participate in the class communities. Habitats are most often characterized by rich soils and moderate moistening.
On the gradient of humidification, as the leading differentiating factor of the Molinio-Arrhenatheretea class meadows, communities of the Arrhenatheretalia order border on the wet meadows of the Molinietalia order on the one side and on the steppe meadows of the Galietalia veri order on the other side.
In the studied area, all the communities of the order are assigned to the central Festucion pratensis alliance.

Festucion pratensis Sipajlova et al. 1985 alliance
Diagnostic species of the alliance = diagnostic species of the order. The alliance is typical for hayfields or mowing and grazing communities with a low pasture load. The grass stand is dominated by grasses Agrostis gigantea, Alopecurus pratensis, Bromopsis inermis, Dactylis glomerata, Festuca pratensis, Phleum pratensis, Poa pratensis. Besides, such herbs as Geranium pratense, Lathyrus pratensis, Leucanthemum vulgare, Vicia cracca actively participate in the composition of the alliance communities. It includes the most typical communities of the Molinio-Arrhenatheretea class. In the conditions of forest and forest-steppe zones, the communities occupy upland and floodplain habitats. According to the Soviet classification by dominants, tall grass meadows formation group include the following formations: bromegrass, bromegrass-quackgrass meadows, foxtail and red-tailed fescue meadows (Shennikov, 1938). Associations of this alliance, determined by the Braun-Blanquet method, basically coincide in volume with the formations listed. The alliance was first described in Ukraine (Sipaylova et al., 1985). According to its initial interpretation, it unites meadow communities on rich soils in Eastern Europe and Siberia and is a vicariant of the Arrhenatherion elatioris Luquet 1926 alliance in Western Europe (Balevičienė et al., 1998;Bulokhov, 2001;Kuzyarin, 2008;Bulokhov, Kharin, 2008;Kuzemko, 2009;Averinova, 2010). The alliance includes 4 communities and one association.
The community encompasses meadows common for upland habitats with moderate soil moistening. They are spread throughout the Biysk-Chumysh Upland (within the territory of Altai Krai). These communities are caracterised by a haying mode of use. The projective cover of the grass stand varies from 60 to 100%. The number of species per 100 m 2 averages 22 (from 19 to 31 species). The height of the grass stand is 65 cm on average.
The community comprises meadows spread in upland habitats with moderate soil moistening. They are described in Troitskiy and Kosikhinskiy districts in the more depressed areas and are used as pastures. The average number of species on the site is 21. The average height of the grass stand is 55 cm. The projective cover of the grass stand varies from 70 to 100%.
It differs from other idle land communities in a relatively low proportion of annual and biennial weeds, representing the initial stages of progressive successions after the disturbances of the Stellarietea mediae class as well as in an increase in the proportion of meadow species of the Molinio-Arrhenatheretea class and species of forest edges and woodlands of Trifolio-Geranietea (Hypericum perforatum, Veronica chamaedrys, Agrimonia pilosa and others).
The community encompasses meadows formed in the conditions of normal and excessive moistening, confined to more acidic soils. They are described in Kosikhinskiy district and are used as pastures. The average number of species on the site is 18. The average height of the grass stand is 60 cm. The projective cover of the grass stand varies from 70 to 90%. The community comprises dry meadows, spread in the conditions of sufficient moistening in all areas of the Biysk-Chumysh Upland (Altai Territory). They are located on meadow and meadow chernozem soils on smooth slopes. The mode of use is haying. The projective cover of the grass stand varies from 70 to 100%. The number of species per 100 m 2 averages 29. The height of the grass stand is 65-70 cm on average.
Besides cocksfoot -Dactylis glomerata, other grasses, mainly rootstock loose-bunch grasses (Poa pratensis, Festuca pratensis, Phleum pratense) take a significant part in the formation of the grass cover. A group of meadow species of the Molinio-Arrhenatheretea class (Agrostis tenuis, Galium mollugo, Phleum pratense, Trifolium pratense, Leucanthemum vulgare) is highly constant. A notable part of the stand is composed of synanthropic species of the Stellarietea mediae class (Berteroa incana, Convolvulus arvensis, Echium vulgare, etc.).
It differs from other studied communities by the predominance of meadow grasses. The association has a wide range in Siberia, its communities are widespread in the subtaiga and forest steppe regions of the Ob-Yenisei interfluve, the subtaiga forest steppe belt of Salair, Kuznetsk Alatau, Western and Eastern Sayan (Dymina, 1989;Makunina, Maltseva, 2003).
The order unites the communities, cenoflora of which combines species of true meadows and meadow steppes, that is usually called steppe meadows in the literature (Shennikov, 1938). The climate changing, steppe meadows transform into meadow steppes. Thus, steppe meadows are ecotones between true meadows and meadow steppes.
A specific feature of the communities in this order is the simultaneous growth of typically meadow species of the Molinio-Arrhenatheretea class and the Arrhenatheretalia order (Achillea millefolium, Bromopsis inermis, Elytrigia repens, Festuca pratensis, Geranium pratense, Lathyrus pratensis, Trifolium pratense, Vicia cracca, etc.) together with meadow steppe species of the Festuco-Brometea Br.-Bl. et Tx. 1943 class (Amoria montana, Centaurea scabiosa, Filipendula vulgaris, Festuca pseudovina, Galium verum, Poa angustifolia, Phleum phleoides, Phlomoides tuberosa, Medicago falcata, etc.). On the humidification gradient, communities of the order border on well-hydrated meadows of the Arrhenatheretalia order on one side and on the communities of the Festuco-Brometea class, uniting xerothermic and hemixerothermic steppe communities on the other side. The diagnostic combination of the Galietalia veri order consists mainly of steppe and meadow steppe species, which are also used to diagnose the Festuco-Brometea class (and its more mesophytic wing -the Festucetalia valesiacea order), which, in this case, act as differentiating species, separating the Galietalia veri steppe meadows from meadows of the Arrhenatheretalia order. Communities of the Galietalia veri order are distinguished from typical steppe communities of the Festuco-Brometea class by the presence of mesophilic meadow species of the Molinio-Arrhenatheretea class. The communities we studied are classified as part of the central Trifolion montani alliance.

Trifolion montani Naumova 1986 alliance
Diagnostic species of the alliance = Diagnostic species of the order. It is the central alliance of the order, comprising its most typical communities. The alliance includes 4 communities.

Elytrigia repens community
Diagnostic species: Elytrigia repens, Festuca pseudovinа. It encompasses steppe meadows, which physiognomy is determined by the dominance of the Eurasian species Elytrigia repens.
They are common for abandoned arable lands, on the edges of fields, along field roads, near villages in Kosikhinskiy district. The community use is grazing. The projective cover of the grass stand varies from 55 to 70%. The number of species per 100 m 2 averages 16. The height of the grass stand is 45 cm on average.
The share of apophytes is high. The community is an advanced stage of a progresssive succession of vegetation. It is close to associations of idle lands of Western and Eastern Convolvulo arvensis-Elytrigietum repentis Felföldy 1943 (Arepieva, 2012) and Pastinaco sylvestris-Elytrigietum repentis Ishbirdin in Ishbirdin et al. 1988. However, the communities that we described differ from them by a higher constancy of meadow species of the Molinio-Arrhenatheretea class in the floristic composition, as well as by the presence of Festuca pseudovina in the cenoflora.
The community comprises steppe meadows, common in the conditions of insufficient moistening in Kosikhinskiy district. Communities are not used; in rare cases, limited grazing is observed. The projective cover of the grass stand varies from 60 to 100%. The number of species per 100 m 2 averages 22. The height of the grass stand is 50 cm on average.
The core of the floristic composition is composed of meadow steppe species of the Galietalia veri order and Festuco-Brometea class (Medicago falcata, Scabiosa ochroleuca, Phleum phleoides, Centaurea scabiosa, Galium verum). Meadow mesophytes of the Molinio-Arrhenatheretea class are less represented, only Poa pratensis and Vicia cracca have constancy class III. A noticeable part of the grass stand is composed of species of the Artemisietea vulgaris and Stellarietea mediae classes (Nonea pulla, Berteroa incana, Potentilla argentea, Echium vulgare, Achillea millefolium, Convolvulus arvensis).
They differ from other communities by a more xerophytic composition.
The community comprises steppe meadows widespread in the conditions of insufficient moisture in Tselinniy, Kosikhinskiy districts. The territory is not used at all or limited grazing is observed. The projective cover of the grass stand varies from 70 to 100%. The number of species per 100 m 2 averages 22. The height of the grass stand is 50 cm on average.
A group of meadow steppe species of the Festucetalia valesiace order, Festuco-Brometea class (Centaurea scabiosa, Medicago falcata, Scabiosa ochroleuca, Galium verum, Phleum phleoides) is highly constant. Meadow species of the Molinio-Arrhenatheretea class (Rumex acetosa, Dactylis glomerata, Elytrigia repens, Leucanthemum vulgare, Plantago media, etc.) and species of the Artemisietea vulgaris class (Dracocephalum thymiflorum, Echium vulgare, etc.) take a significant share in the grass stand. It differs from other communities by the predominance of steppe and meadow steppe species and represents the most advanced stage towards the formation of meadow steppes of the Festuco-Brometea class.

Conclusion
The meadow phytocenoses of the Molinio-Arrhenatheretea class are represented by three orders (Molinietalia, Arrhenatheretalia, Galietalia veri), which comprise wet, true and steppe meadows, respectively. The syntaxonomic analysis of the studied area revealed 1 association, 9 rankless communities, which are characterized by leading environmental factors (humidification gradient) and the level of use (grazing, haying, idle land).