Grazing is one of the most important factors influencing community structure and productivity in natural grasslands. Fencing to exclude grazers is one of the main management practices used to protect grasslands. Can fencing improve grassland community status by restraining grazing? We conducted a field community study and indoor soil analyses to determine the long-term effects of fencing and grazing on the above-ground community and soil in a Kobresia-dominated meadow in the Qinghai-Tibetan Plateau, NW China. Our results showed that fencing significantly improved aboveground vegetation productivity but reduced plant density and species diversity. Long-term fencing favored the improvement of forage grass functional groups and restrained the development noxious weed functional groups. There were significant positive effects of fencing on below-ground organic matter, total nitrogen, available nitrogen, total phosphorus and available phosphorus. The productivity of grazed meadow showed a weak decrease over time. There were long-term decreasing trends for plant density both in fenced and grazed meadows. Our study suggests that grazing can be considered as a useful management practice to improve species diversity and plant density in long-term fenced grasslands and that periodic grazing and fencing is beneficial in grassland management.

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Seasonal grazing is one way of the moderate grazing regimes, but little information is available on compared study of seasonal grazing in alpine meadow. We studied the aboveground and belowground properties among warm-seasonal grazing meadows and cold-seasonal grazing meadows on the Qinghai-Tibetan Plateau. Results showed that the warm-seasonal grazing increased forb functional group proportion, plant density and evenness index but decreased root biomass, plant height and graminoid functional group proportions. Grazing seasons affected variation in soil bulk density, soil water content, pH and soil nutrient content, and the variations caused the various of soil carbon and nitrogen density. The highest values of soil carbon and nitrogen contents and densities in the warm-season grazing meadow occurred at the top 10-cm soil, while the highest values in the cold-season grazing meadow occurred at the depth of 30-to 50-cm soil. Our results indicated that the warm-season grazing is suitable for the species diversity conservation and the nutrient sequestration at the topsoil. However, the coldseason grazing is suitable for the nutrient sequestration at the deep soil. This study implied that the warm-season and cold-season grazing might be exchanged regularly to practice continuous carbon and nitrogen sequestration. Periodic cold-season and warm-season grazing would be the suitable grazing regime to keep alpine meadow sustainability.

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