Grazing effect on growing season ecosystem respiration and its temperature sensitivity in alpine grasslands along a large altitudinal gradient on the central Tibetan Plateau
Grazing effect on growing season ecosystem respiration and its temperature sensitivity in alpine grasslands along a large altitudinal gradient on the central Tibetan Plateau
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DOI：
10.1016/j.agrformet.2015.12.005
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发表时间：
2016-03
影响因子：
6.2
通讯作者：
Jingxue Zhao;T. Luo;Ruicheng Li;Xiang Li;L. Tian
中科院分区：
文献类型：
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作者：
Jingxue Zhao;T. Luo;Ruicheng Li;Xiang Li;L. Tian
关于牲畜放牧如何改变季节性生态系统呼吸（Re）及其温度敏感性（Q10）的海拔趋势，人们知之甚少。我们的目的是检验以下假设：海拔放牧对生长季 Re 的影响与放牧引起的植物生物量的变化密切相关，放牧排斥往往会降低沿海拔高度的 Re 的 Q10。我们在青藏高原中部高寒草甸的下限和上限（4400-5100 米）进行了为期 7 年的海拔放牧排除实验。 2012-2013 年生长季节期间，在 6 个海拔高度的围栏和放牧处理中观察到植物生物量、Re 和相关环境因素。禁牧对地上、地下生物量的刺激随着海拔的升高而降低，与Re的变化呈正相关。季节性Re的Q10总体上随海拔的升高而增加，但在禁牧条件下则呈下降趋势。土壤有机碳对Re的海拔变化没有直接影响。我们的数据支持了这些假设，表明植物生物量变化可以作为 Re 时空变化的综合指标。放牧排除可能是降低铼温度敏感性的一种有前途的措施。
Little is known about how livestock grazing could modify altitudinal trends in seasonal ecosystem respiration (Re) and its temperature sensitivity (Q10). We aim to test the hypotheses that the altitudinal grazing effect on growing-season Re is well correlated with the grazing-induced change of plant biomass, and grazing exclusion tends to reduce theQ10of Re along altitudes. We conducted a 7-year altitudinal grazing exclusion experiment across lower and upper limits of alpine meadows (4400–5100 m) on the central Tibetan Plateau. Plant biomass, Re and related environmental factors were observed across fenced and grazed treatments at each of 6 altitudes during the growing seasons of 2012–2013. The stimulations of above- and belowground biomass due to grazing exclusion decreased with increasing altitude, which were positively correlated with the change of Re. TheQ10of seasonal Re generally increased with increasing altitude, but tended to decrease under grazing exclusion. Soil organic carbon did not have a direct effect on the altitudinal variation of Re. Our data supported the hypotheses, suggesting that plant biomass change could be served as an integrated indicator for spatiotemporal variations of Re. Grazing exclusion might be a promising measure to reduce the temperature sensitivity of Re.