Растительность города Салавата (Республика Башкортостан). V. Естественная и полуестественная травяная растительность (классы Molinio-Arrhenatheretea, Festuco-Brometea и Thero-Salicornietea)

Abstract

The big cities are ecosystems where the most of the planet population is concentrated. The urban environment is characterized by essential changes of substances circulation, energy flow and the ecological conditions important for vegetation growing (Vladimirov, 1986; Odum, 1986; Burda, 1991; Goryshina, 1991; Berezutski, 2007 etc.). At present, urbanized territories of the world occupy only 5% of the entire land, and about 3 billion people live there., Increase of urbanization forces us to study the vegetation cover of the cities. Within city line, two main variants of vegetation communities are distinguished. The first is anthropogenic. It includes man-planted vegetation and widespread communities of synanthropic species. The second variant represents the remains of natural communities ecotopes on the urban territory. Native and semi-native herb vegetation of Salavat town (classes Molinio-Arrhenatheretea, Festuco-Brometea and Thero-Salicornietea) is classified to 6 orders, 9 unions, 10 associations, 1 subassociation, 7 variants and 6 communities. Among them 3 associations (Elytrigio repentis–Bromopsidetum inermis, Sedo acris–Festucetum pseudovinae, Astragalo austriacae–Stipetum pulcherrimae), 1 subassociation (F. v.–C. f. poetosum angustifoliae) and 5 communities (derivate community Solidago canadensis [Arrhenatheretalia], basal community Poa angustifolia [Cynosurion/Onopordetalia acanthii], derivate community Lolium perenne [Cynosurion] and communities of Geranium sibiricum and Suaeda corniculata) are described for the first time in the South Urals. Grassland communities of the class Molinio-Arrhenatheretea maintaining some trampling and pasture (in the city suburbs) are most widespread. They are rather diverse due to a wide range of ecological characteristics of the habitats (disturbance, moistening, and characteristics of substratum). The steppe vegetation of the class Festuco-Brometea is remained on the southern and eastern slopes of the uplands. The class Thero-Salicornietea communities on habitats with technogenic salinification occur locally. When building the city most of natural vegetation communities were destroyed, or they were transformed in semi-natural phytocoenosis with a high number of synanthropic species in floristic structure. The remained fragments of natural vegetation make an essential contribution, both to city flora, and to urban vegetation. They are refuges of many plant species, including rare and endemic species of the plants. Among endemic species — 1 species (Astragalus wolgensis). Two species (Stipa pulcherrima, S. pennata) are included in the Red List of the Russian Federation and also 2 species from the Red List of Bashkortostan Republic (Stipa korshinskyi and Tulipa biebersteiniana) were revealed. The rare plant species were described in steppe communities and the steppe meadows. These ecosystems need to be protected urgently.