PHYTOCOENOTIC BEHAVIOUR OF MULTIZONAL MEADOW PLANT SPECIES IN MEADOW STEPPES
I.B. Kucherov1, L.A. Novikova2, S.A. Senator3
1V.L. Komarov Botanical Institute RAS, St. Petersburg, Russia 2Penza State University, Penza, Russia 3N.V. Tsitsin Central Botanical Garden RAS, Moscow, Russia
Keywords: multizonal species, meadows, dry grasslands, meadow steppes, latitudinal zonation, European Russia
Abstract
As follows from the analysis of relevés collected in the 13 key areas in European Russia (see Table 1, Fig. 1), phytocoenotic behavior of many multizonal meadow species of vascular plants changes notably when passing from the boreal- and then the nemoral-forest zones to the subzone of meadow steppes. The constancy and cover of the 17 model species, distributed along the latitudinal zones and subzones and then the dry grassland, meadow, and steppe vegetation types (see Table 2), is influenced by warmth supply and climate continentality factors together with those of location within a particular river basin and regional specifics of the Quaternary history. Zonal trends of cover changes for Stellaria graminea and Bromopsis inermis in the series from dry boreal grasslands to steppes or from northern to southern Calamagrostis epigeios-dominated meadows, respectively, are proved by the Spearman rank correlations between the mean cover and the growing degree-days above 10 C or the Konrad continentality index (see Table 3). Xerophytization of many species, mesic in the boreal-forest zone, is observed under the steppe conditions, the process which often results in the separation of new micro-species. The anemochorous meadow plants were subject to dispersal mainly along the watersheds but the barochors were dispersed mainly by water flow or in both ways in the course of the formation of meadow-steppe coenofloras in the Late Pleistocene and the Holocene. Both redwood-dry-grassland and floodplain-meadow coenofloras influence the steppe set of meadow species, and the latter can be grouped into the three ecological-historical “corteges” of vegetation, namely the watershed, the floodplain, and the combined ones.
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