Characteristics and recovery capacity of plant community in Grave-Soil-Taken Field during natural restoration in alpine steppe

The natural restoration process of plant community in Grave-Soil-Taken Field which formed by road construction at different stages in the alpine steppe of Tongde county in the Three-River Source Region was studied in the present research. The combined community field survey and soil analysis were employed to investigate the natural succession of alpine steppe vegetation of Grave-Soil-Taken Field. The results showed that total above-ground biomass increased with restoration time. However, the total aboveground biomass of plant community in Grave-Soil-Taken Field had no significant difference with the control plots after 30 years of vegetation recovery. The total underground biomass in Grave-Soil-Taken Field fluctuated between 5 years and 30 years after road construction. Furthermore, the total underground biomass was significantly lower (P0.05) than that of control after 30 of vegetation recovery. Species diversity significantly increased (P0.05) between 5 years and 30 years after road construction. Comprehensive recovery capacity of alpine steppe decreased with recovery time increasing. The stability of plant communities increased with recovery time increasing. After 30 years of natural restoration, the plant communities were relatively stable. Changes of soil nutrients, especially organic mass and available phosphorus had significant influence on the productivity of plant community, species diversity and comprehensive recovery capacity.