Response of the plant community and soil water status to alpine Kobresia meadow degradation gradients on the Qinghai-Tibetan Plateau, China
Response of the plant community and soil water status to alpine Kobresia meadow degradation gradients on the Qinghai-Tibetan Plateau, China
复制标题
青藏高原植物群落和土壤水分状况对高寒嵩草草甸退化梯度的响应
DOI：
10.1007/s11284-015-1258-2
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发表时间：
2015-07-01
影响因子：
2
通讯作者：
Cao, Guangmin
中科院分区：
文献类型：
--
作者：
Li, Jing;Zhang, Fawei;Cao, Guangmin
青藏高原高寒嵩草草甸退化严重，但其对植物群落和土壤水分状况的影响尚未完全清楚。我们选择了四个均匀的网站< 20，20-70，70-90，和> 90%的美味草的绝对丰度，并将它们分为退化梯度类别差，一般，良好，和优秀，分别。地上生物量和入渗速率均以一般样地最低，根系生物量、表层草层厚度、表层（< 10 cm）有机质含量和根土体积比均以一般样地最高。植物群落多样性和表层土壤容重在退化梯度间波动较小。非度量多维尺度的结果表明，高寒嵩草草甸植被动态沿着退化过程是非平衡的。退化对土壤含水量和持水量的影响在表层（> 10 cm）最大。土壤表层含水量的最小值和最大持水量均出现在一般样地，表明土壤水分含量和持水量在沿着退化梯度上存在明显的不平衡，可能通过生理干旱和养分亏缺导致植物群落的非平衡格局。研究结果为今后高寒嵩草草甸退化草地的阈值管理提供了重要参考。
Degradation of alpine Kobresia meadow in the Qinghai-Tibetan Plateau is a serious problem, but its effect on the plant community and soil water status is not fully understood. We chose four homogeneous sites with < 20, 20-70, 70-90, and > 90 % absolute abundance of palatable grasses, and classified them as degradation gradient categories of poor, fair, good, and excellent, respectively. The lowest aboveground biomass and infiltration rate, and the highest root biomass, thickness of mattic epipedon, topsoil (< 10 cm) organic matter content and volumetric ratio of root/soil all occurred in fair plots. There was little fluctuation in plant community diversity and topsoil bulk density among the degradation gradients. Results of non-metric multidimensional scaling suggested that vegetation dynamics along degradation processes were non-equilibrium in the alpine Kobresia meadow. The effects of degradation on soil water content and retention were the highest in the top layer (> 10 cm). The minimum topsoil water content and maximum topsoil water retention both occurred in fair plots, indicating asynchrony between soil water content and holding capacity along degradation gradients, which likely resulted in a non-equilibrium plant community pattern through physiological desiccation and nutrient deficits. Our findings should be highly informative for threshold-based management of the degraded alpine Kobresia meadow in the future.