Распространение и эколого-фитоценотические особенности Asparagus brachyphyllus Turcz. в Восточном Забайкалье

Abstract

Asparagus brachyphyllus Turcz. is a rare species in Russia. It’s a herbaceous perennial plant with short horizontal rhizome which gives 1-6 annual shoots. According to the literature the species grows in saline steppe and around salty lakes. In conditions of Eastern Transbaicalia vegetation lasts a little more than four months from middle May to late September, fruiting from June to September. A. brachyphyllus is listed in Red Book of Russian Federation, it is protected in Daursky State Nature Biosphere Reserve. In Transbaicalia it is limitated by small area of habitats, narrow environmental tolerance, low numerity of populations, grazing (annual shoots are eagerly eaten by animals, especially in spring). A. brachyphyllus has eastern-asian steppe (in the narrow sense) type of distribution, the main part of area is in North-East of China and in the East of Mongolia. In Russian Federation it occurs only in steppe districts of Zabaikalsky kray where there is the northern distribution limit. During our many years field expeditions new localities of A. brachyphyllus in Zabaikalsky Region were descripted, information on ecological-phytocenotic features and populations condition at the northern area limit was expanded. Localities of the species were identified at South and South-East of Zabaikalsky kray: Argun area, Aga steppe and Torey lake surroundings; most of localities are concentrated near Torey lakes, in other areas localities are sporadic. A. brachyphyllus grows mostly in Achnatherum splendens and Achnatherum splendens – Leymus chinensis saz steppe communities on solonetz soils, also on soil complexes of solonez and solonchack, sometimes it occurs on solonchacks in hyperhalophytic communities with Kalidium foliatum, Limonium aureum, Suaeda corniculata, Puccinellia tenuiflora. In plant communities A. brachyphyllus appears as a species with low abundance and coverage less 1%; due to prostrate form of shoots they place in lower layer up to 10 cm. In few-species communities on solonchacks A. brachyphyllus has low abundance, and a little higher on solonetz. In last case both species number and density of asparagus coenotic population are higher as usual. For estimation coenotic populations vitality we used a complex of criteria: density of coenotic populations, projective cover of species, markers of generativeness. Numerous Torey coenotic populations most often have medium vitality while that of coenotic populations at Aga localities higher. About a half of revealed coenotic populations suffer temperate influence of livestock grazing which lessens vitality by trampling and partial eating. Some localities at Torey lakes area need special protecting measures.