Phytodiversity and bioproductivity of the Leymus chinensis steppes in eastern Transbaikalia

Abstract

The research objective is caused by wide spread of leymus communities in the southeastern Transbaikalia and gaps in studying their species composition, structure, and phytomass accumulation; it is to give a phytocenotic characteristics of leymus communities in the steppe zone of eastern Transbaikalia, and to determine the level of their biological productivity using standard geobotanical, agrochemical and soil methods. The paper studies monodominant Leymus chinensis communities growing on various soil types of meadow steppe, steppe floodplain meadows and haloxerophytic steppe of the south-eastern Transbaikalia. The species composition of communities is represented by 21 families, 45 genera, 62 species. Halophytes account for 11.3 % (7 species), halotolerant – 29 % (18 species), glycophytes – 59.7 % (37 species). The species of the families Asteraceae – 30.6 %, Poaceae – 17.7 %, Rosaceae – 8 % form the largest share in the projective cover of communities. The rest families are of 1 – 2 species. The species composition of Leymus is represented mainly by the steppe complex with xerophytes different variants belonging to the Asian type of area. The main part belongs to rhizome species in the biomorph composition, and the share of annuals and biennials is significant as well. The similarity between communities is within the range from low to medium, which is due to the great participation of single-species families and genera. The authors have assessed the contribution to aboveground phytomass of a dominant species, Leymus chinensis, other species and died grass. The greatest contribution of ears to the aboveground phytomass is marked only in Descriptions 4 and 5. The primary production of Leymus chinensis communities is estimated as high, 2105 – 3189 g/m2 a year. Underground phytomass is 84 – 94 % of the total productivity. The underground and aboveground phytomass ratio is 1:5 – 15, that is determined by various soil and environmental conditions of growing the communities.