Effect of fences on functional groups and stability of the alpine meadow plant community in the Qinghai-Tibet Plateau

The changes in community structure and stability of the alpine meadow ecosystem under artificial conditions are an important way to study its ecological function. To explore this kind of change in the Qinghai-Tibet Plateau, field investigations within and outside of fences in a permanent sample plot (established in 2005) in Wumatang were conducted in August of 2009 and 2013. Species richness(R), differences in functional groups, and M. Godron stability index were analysed to explore the differences between fenced and unfenced communities. The results showed that 1) the species richness of the fenced community was greater than unfenced; the number of annual and biennial plants in the fenced community was significantly greater than in the unfenced one in 2009; the dominant species of the fenced community changed from Kobresia pygmaea to Pedicularis kansuensis by 2013, and species belonging to perennial grasses, forbs, and annuals and biennials meant the fenced community was obviously richer than the unfenced community; and 2) the M. Godron stability index showed that the fenced community was more stable than the unfenced one in 2009, but less stable than the unfenced community in 2013. The fenced community structure showed an obvious change and the stability presented a downtrend as the time went by, whereas the stability of the unfenced community presented an uptrend.