Phytocoenotic diversity of the gray alder forests the Southern-West of Nechernozemye of Russia
Authors: Semenishchenkov Yu. A. 
Published: February 2020

In the paper the phytocoenotic diversity of gray alder forests, common in the South-Western Nechernozemye of Russia, is characterized. On the territory of studies A. incana occurs in Bryansk, Kaluga, Smolensk and Orel regions. In the European Russia gray alder forests represented by a lot of forest types described by T. A. Rabotnov (1939), A. A. Nitsenko (1972), V. I. Vasilevich (1998), S. V. Degteva (2002), N. S. Liksakova (2004) etc. At the southeastern border of A. incana distribution in the South-Western Nechernozemye of Russia the gray alder forests are presented by mesophytic and hygrophytic ecologic-dynamic groups. Hygrophytic forests probably represent the azonal-zonal type of forest vegetation which is widespread in the valleys of rivers and streams. They are characterized by the presence and high constancy of hygrophyte and helophytic species. These forests belong to the alliance Alnion incanae, but they have essential floristic differences with hygrophyte alder forests of the Central Europe. Plant communities described from the South-Western Nechernozemye of Russia are characterized by a lack of Western- and Central European species, which are widely represented in Germany, Poland, Slovakia, Czech Republic and partly Ukraine: Acer pseudoplatanus, Carex brizoides, Circaea lutetiana, Chaerophyllum hirsutum, Geranium phaeum, Euonymus europaea, Lysimachia nemorum, Primula elatior, Ranunculus lanuginosus, Sambucus nigra, Viola reichenbachiana. In the Central Europe the communities of the ass. Alnetum incanae include the constantly-varying species: Abies alba, Anthriscus nitida, Astrantia major, Carduus personata, Carex remota, Carpinus betulus, Chrysosplenium oppositifolium, Cruciata glabra, Dactylis polygama, Doronicum austriacum, Euphorbia amygdaloides, Fagus sylvatica, Gentiana asclepiadea, Heracleum sphondylium, Petasites albus, P. hybridus, Prenanthes purpurea, Salvia glutinosa, Senecio nemorensis, S. ovatus, Symphytum cordatum, Valeriana dioica, etc. In communities of the Northern part of European Russia absent some nemoral species: Acer platanoides, Adoxa moschatellina, Ajuga reptans, Brachypodium sylvaticum, Carex sylvatica, Corylus avellana, Daphne mezereum, Galium odoratum, Fraxinus excelsior, Lamium maculatum, Mercurialis perennis, Poa nemoralis, Quercus robur, Ranunculus auricomus, R. cassubicus, Scrophularia nodosa, Stachys silvatica, Tilia cordata, Ulmus glabra. These species are more widely represented in Central European forests, as well as in communities of the South-Western Nechernozemye of Russia – near the southern border of the hemiboreal forests. The results of the floristic comparison do not allow considering our forests to be belong to the ass. Alnetum incanae Lüdi 1921 distinguished for the Central Europe Therefore they are allocated in the new ass. Scirpo sylvatici―Alnetum incanae ass. nov. hoc loco. The plant communities differentiate the block of predominantly helophyte and hygrophyte species characteristic for riparian habitats and communities of wetland forests: Agrostis canina, Calliergon cordifolium, Juncus effusus, Glyceria fluitans, Lycopus europaeus, Scirpus sylvaticus, Solanum dulcamara, Stachys palustris. Two variants of the association were discribed. Chaerophyllum aromaticum var. communities are characterized by the dominance of nitrophilous species Chaerophyllum aromaticum. Var. typica combines typical communities and it has no own diagnostic species. The mesophytic alder forests of the Southern Nechernozemye of Russia represent stages of demutation restoration of the mesic spruce and broad-leaved-spruce forests of the order Fagetalia sylvaticae. The specified successional status does not allow considering the mesophytic communities of a gray alder as an independent association. More correct to refer them to the temporary facies of ass. Rhodobryo rosei―Piceetum abietis Korotkov 1986, similar to the secondary birch and aspen forests representing widespread changes of the mesophytic spruce and broad-leaved-spruce forests. This facies is characterized for three variants established by the dominance of some plant species. The most mesophytic forests are represented by var. Galeobdolon luteum, which differentiated by mesophytic species of spruce and broad-leaved-spruce forests: Galeobdolon luteum, Corylus avellana, Stellaria holostea. Communities with abundant undergrowth of Padus avium, formed along the margins of forest swamps in wet loam, were classified as var. Padus avium. Its diagnostic species are following: Padus avium, Crepis paludosa, Stachys sylvatica. Var. typica combines typical communities and it has no own diagnostic species as well. The floristic peculiarities and a role of the ecological factors in differentiation of syntaxa are demonstrated by the DCA-ordination. Communities of the South-Western Nechernozemye of Russia are largely differentiated from the others on the complex gradient corresponding increase in soil moisture, light and temperature. In general, the DCA-1 axis can be regarded as a complex gradient of continentality, soil richness, and the reaction of the substrate; DCA-2 – soil moisture, temperature, and light.