[Effect of grazing rate on biomass and element composition of Xanthoparmelia camtschadalis]

Xanthoparmelia camtschadalis is widely distributed in grassland area of Mongolian Plateau. There are few studies on the relationships between biomass, element composition and stocking rate. The relationships of biomass and element composition of Xanthoparmelia camtschadalis to grazing rates in Leymus chinensis steppe in Inner Mongolia were investigated. The results indicated that the biomass of the lichen was highest under light grazing, while the lowest under extremely overgrazing treatment. The C, N and Ca concentrations were higher than 1%, P, Mg, K and Fe were between 0.1% and 1%, and Na, Mn, Cu, Zn, and B were less than 0.1%. The Ca content in Xanthoparmelia camtschadalis was much higher than that in vascular plant. With an increasing grazing rate, the C concentration decreased, while N increased. The C/N ratio was the lowest under moderate and heavy grazing treatments. Ca, Mg, K, Fe, Mn and Cu contents were higher under grazing treatments. The changes of biomass and element composition of Xanthoparmelia camtschadalis had a good response to grazing rate, and hence, it was a good indicator to indicate the healthy condition and changes of biogeochemistry cycles in grassland ecosystems.