Responses of aboveground biomass and species richness to environmental factors in a fenced alpine grassland

Degraded alpine steppe is increasing, which limits the sustainable development of regions. The influences of soil physical and chemical properties on the aboveground biomass and community biodiversity, under the measures of fence restoration, were analyzed in this study. In addition, the critical regulators for plant recovery in degraded grasslands were explored. Consequently, the investigation of grazing exclusion 4, 5, 7, 8, and 9 years were conducted in the Shenza area of Tibet. The findings presented that: 1) In the enclosure steppes, the community biodiversity, aboveground biomass, and vegetation coverage increased at first and then decreased in 7 years. 2) The aboveground biomass and community biodiversity were positively correlated with the soil water content, soil organic matter, soil available nitrogen, and soil total nitrogen while negative relationship was found between the pH and soil bulk density. Our study highlighted that the key to the recovery of degraded grasslands is enhancing the soil water content and nutrients, moreover, seven years of grazing exclusion is the optimum duration in the alpine steppe of Northern Tibet.