Results of experiment on vegetation restoration after overgrazing in conditions of Ulz River valley (North-Eastern Mongolia)

UDC 581.55:58.02:574.42(517)

Abstract

The article presents the results of an experimental three-year vegetation restoration in the Uldzy River valley in northeastern Mongolia after overgrazing by the fencing method. In the Chukh Lake vicinity, three pairs of sample plots of 100 m² were studied in the steppe and two meadow communities under conditions of overgrazing and after a three-year removal of the grazing pressure. Vegetation in the study area is in the stage of strong pasture digression, which is manifested in low production indicators, dominance of low-growing species resistant to grazing and a decrease in species number. Changes in vegetation indicate a significant decrease in its soil-protecting properties, which contributes to the development of soil erosion. The absence of grazing for three years led to a significant increase of green mass, dry grass and litter; the minimum value of phytomass without grazing is always higher than the maximum one with grazing in all three pairs of communities. Inside the fence, the grass stand had a greater density, height and the vertical structure complexity. During the experiment, the quantitative relationships between species in the communities changed to close to natural ones, which indicates the demutational potential of the pastures in North-Eastern Mongolia. Fencing can be used as an effective method for restoring degraded pastures.