Investigation on community characteristics and diversity of Carex cinerascens meadow steppe in Poyang Lake wetland

Carex cinerascens, which is one of main constructive species at meadow steppe in wetland of Poyang Lake, plays an important role in functioning Poyang Lake ecosystem. A research of simple investigation was conducted to determine the species composition, community coverage, height, aboveground biomass and species diversity of C.cinerascens meadow steppe in three plots located in Wutown, Jiangxi province in 2010. The results showed that species composition of C.cinerascens community was simple and only 8 main species were observed in these plots, among which C.cinerascens was dominant. The highest and lowest values of Margalef richness index, ShannonWiener diversity index and Simpson sominance index of C.cinerascens community in three plots were 0.88, 1.35, 0.65 and 0.46, 0.46, 0.23, respectively. It was suggested by correlation analysis that Margalef richness index was more closely associated with the species diversity of C.cinerascens community. The community coverage(63.27%-100%), community height(4.25-14.12 cm) and aboveground biomass(1 377-3 080 kgha-1) were lower than those in average years. Variation of water level and grazing disturbance may be responsible for the changes of C.cinerascens community in Poyang Lake wetland.