Structure of the vegetation cover of the Amut Basin (Dzherginsky nature reserve, The Republic of Buryatia)

Abstract

Large-scale vegetation mapping makes it possible to assess the spatial structure of communities at the local level. The Amut Basin is one of the small intermountain basins of the Baikal rift zone. The basin was formed in a complex orographic junction of the Barguzinsky, Severo-Muysky, Yuzhno-Muysky and Ikatsky ridges. The basin is a part of the Dzherginsky Nature Reserve. It was organized to protect the natural complexes of the sources of the Barguzin River. Despite the simplicity of the vegetation structure, there is an interpenetration of elements of different phratries of formations — the Ural-Siberian, Angarid and Berengian. This indicates a complex history of the development of the vegetation cover of the territory. A large-scale geobotanical map makes it possible to create the basis for a balanced protection of the natural complexes of the reserve and contributes to identifying the local structure of the vegetation cover of the Baikal rift zone. Analysis of the resulting map shows the relative simplicity of the communities diversity in the basin. 12 groups of indigenous associations and 3 categories of derived communities have been identified. The main coenogenetic groups were not identified due to the insignificant participation of elements of the Ural-Siberian and Berengia phratries of formations. The dominant formations in the basin belong to the Angarid phratry. They are represented by Dahurian larch communities. The Berengian element of cenoses, Pinus pumila, dominates in limitedly widespread cenoses, but as an undergrowth it is found everywhere in larch forests. Pure dark coniferous forests of the Ural-Siberian phratry of cedar (Pinus sibirica) and fir (Abies sibirica) were not recorded on the territory of the basin; however, cedar undergrowth and individual cedar specimens are found regularly on the territory. Spot growth of an element of the South Siberian formations of the Ural-Siberian phratry — Caragana jubata — in coastal shrub and forest cenoses should be noted. The overall disturbance of the area’s vegetation cover is low. Traces of fires in the basin are sporadic, and burnt areas distribution is limited. Regeneration processes are actively taking place in burnt areas. The main role in the preservation of the natural complexes of the Amut Basin is played by the fact that the basin with adjacent territories is the part of the Dzherginsky Nature Reserve. The reserve was founded on the basis of a complex zakaznik (protected area) that existed here since 1974. The created map can serve as the basis for conducting monitoring observations of succession processes in the territory, identifying widespread and less widespread cenoses in the reserve, and also for zoning the territory for environmental purposes. Currently, it is planned to create a large-scale vegetation map for the entire territory of the Dzherginsky Nature Reserve.