Grazing alters ecosystem functioning and C : N : P stoichiometry of grasslands along a regional precipitation gradient

作者：Yongfei Bai, Jianguo Wu, Chris M. Clark, Qingmin Pan, Lixia Zhang, Shiping Chen, Qibing Wang, Xingguo Han · 发表于：Journal of Applied Ecology · 年份：2012 · DOI：10.1111/j.1365-2664.2012.02205.x · 被引用次数：388 · 研究领域：Ecology and Vegetation Dynamics Studies、Plant Parasitism and Resistance、Botany and Plant Ecology Studies

Summary The Eurasian steppe has long been subject to grazing by domestic ungulates at high levels, resulting in widespread deterioration of biodiversity and ecosystem services. While abundant evidence demonstrates that heavy grazing alters the ecosystem structure and function of grasslands, research on how grazing specifically affects ecosystem functioning and stoichiometry on broad scales is scarce because of a lack of adequate ungrazed reference sites. We examined the effects of grazing on ecosystem functioning and C : N : P stoichiometry across a precipitation gradient along the 700 km C hina– M ongolia transect ( CMT ), covering three community types: meadow steppe, typical steppe and desert steppe. Long‐term grazing has dramatically altered the C , N and P pools and stoichiometry of steppe ecosystems along the CMT . Grazing reduced the C , N and P pools in above‐ground biomass and litter, while the responses in below‐ground biomass and soil C , N and P pools to grazing differed substantially among community types. Grazing increased N content and decreased C : N ratios in all plant compartments, suggesting accelerated N cycling. The altered C : N : P stoichiometry may be explained by changes in the composition of species and functional groups as well as increased foliar N and P contents for the same species in grazed communities. Synthesis and applications . Plant stoichiometric responses to grazing ranged from large in the meadow steppe to small in the typical steppe to ...