Fallow Lands of Tuva (Russia): 30 years of Steppe Demutation

Abstract

Tuva has been a cattle-breeding region since ancient times, extremely continental climate of this region is little suitable for agriculture. However, the steppes of intermountain depressions in Tuva were heavily plowed by the early 1980s. In the 1990s most of the arable lands were abandoned; the process of restoration (demutation) of natural vegetation on fallow lands began. By now, 30 years later, the old fallows are expected to achieve the stage of the secondary steppe. The purpose of this work is to estimate the differences between virgin steppes and corresponding secondary steppes in Tuva. Tussock, hummock, and desert virgin steppes have been compared with corresponding to three types of 30-year-old fallow communities. For this study, 330 geobotanical releves have been used. The criteria for comparison have been chosen as follows: the similarity of species composition, the spectrum of dominant species, species richness, grass cover, and grass height. The statistical validity of their differences has been verified. According to these criteria, virgin steppes and their 30-year-old fallow derivatives are shown to differ significantly.