Geographical and phytocoenotic areas of endemic of the South Urals Delphinium uralense Nevski

The geographical and phytocoenotic areas of the endemic of the Southern Urals Delphinium uralense that is a relic species of the ancient Pleistocene steppe were studied. Species is listed in the Red book of the Russian Federation (2008) and the Red Book of the Republic of Bashkortostan (2011). The main part of the geographical area of the investigated species is limited by the Zilair plateau located in the south-western tip of the Ural Mountains, within the Urals fold-block surface. The phytocoenotic area of this species includes the xerophytic communities referring to 2 classes, 3 orders, 4 alliances, 1 suballiance, 2 associations, 1 subassociation, 1 variantand 4 non-ranking communities

The formation of the unique complex of xerophytic oak-larch sparse forests and rocky steppes in the southern Urals is linked with the occurrence of the mountainous steppe with larch groves, which were the remnants of the xerophytic mountain landscape —“Pleistocene floristic complex” (Igoshina, 1961, 1963).

The enrichment the floristic composition of the complex took place in the late Pleistocene due to following facts: the appearance of rock and mountain-steppe Asian relict species (Ryabinina, 1993), the migration of Eastern Siberian elements to the West, the movement of European species to the East, the formation of the Urals endemic floristic races (Krasheninnikov, 1939). Later, in the Holocene, the Pleistocene floristic complex was enriched by some species of broad-leaved forests (including oak Quercus robur), the penetration ofthe south richsteppe flora, and replenishment of the floristic complex by the Pontic and Sarmatic species (Igoshina, 1961).

As a result of mentioned above processes a unique complex of xerophytic rocky mountain steppes and of sparse oak and larch elfin woodswas formed in the Zilair plateau.

Thus, the narrow geographical and coenotic areas as well as the endemism of Delphinium uralense allow us to make a suggestion that the species is a relic of Pleistocene steppe floristic complex.

Anthropogenic degradation of rocky steppes and xerophytic oak-larch crooked forests leads to the replacement of their derivatives by the ruderal and semiruderal communities. They dominate in the territories including the area of the present distribution of D. uralense. The main potential area this species ­covers about 26 000 ha.

Lack of regulated grazing can cause in the future the disappearance of relict species and the whole unique complex of relict forest-steppe vegetation occurring in the Western and South-Western parts of Zilair plateau.