Site Description
This study was conducted at the long-term Alpine Meadow Ecosystem Research Station of Lanzhou University in Walaka, in the eastern Tibet Plateau of China (35°58′N 101°53′E, 3500 m above the sea level). The climate of this region is humid-alpine, with a mean annual temperature of 1.2°C, and mean annual precipitation is 620 mm (mostly in summer). The soil is sub-alpine meadow soil, and the vegetation, consisting mainly of arctic-alpine and Chinese Himalayan plants, is dominated byKobresia sp ., Festuca ovina , and poophagorum. The experimental site was fenced and only grazed from winter to early spring (October to April in the subsequent year) since 2000.