Vegetation cover of subtaiga landscapes in premountain plain on a right bank of the Ob river

Abstract

Vegetation of the right bank of the Ob River in the limits of Novosibirsk area consists of southern taiga, subtaiga and forest-steppe elements. More over, in comparison with neighboring areas on the West Siberian Plain, it contains the significant amount of mountain elements (Kuminova, Vagina, Lapshina, 1963). Natural vegetation of the area belongs to the forest-steppe subzone of the West Siberian province (Il’ina, 1985). Low percentage of forest coverage is caused by anthropogenic deforestation and wide distribution of meadows (Lapshina, 1963). This is the most endangered vegetation in Novosibirsk area. Spatial vegetation structure was studied by using the model of the Ob River basin covered 184 square kilometers. Well-developed system of ravines and small creeks caused a presence of relatively large areas with very low anthropogenic impact which potentially could be the refuges of pristine zonal vegetation. Main vegetation type of this basin is forest which covered about 31% of the area. Forest diversity of model area consists of four syntaxa of association and subassociation ranks belonging to the Brachypodio pinnati–Betuletea pendulae class. Meadow vegetation is presented by five syntaxa from the Molinio-Arrhenatheretea class and mire vegetation — by two syntaxa from the Alneteae glutinosae class. Two subassociations and four variants are described for the first time. The ravine systems could be considered as low-level landscape structures which are the natural refuges with high level of biodiversity and habitats of rare and endangered species. The slope vegetation organized in ecological rows consists of three up to four syntaxa changing from the top to the ravine bottom. The Ob River Basin flora is characterized by insignificant amount of meadow steppe species, well-represented mire flora and a presence of mountain and taiga elements. The most specific floristic features are the presence of ephemeroid species, taiga species and Siberian tertiary nemoral relics (Polozhiy, Krapivkina, 1985). All these features allow us to refer the river basin vegetation to the low-mountain subtaiga type.