Nitrogen enrichment enhances the dominance of grasses over forbs in a temperate steppe ecosystem
Nitrogen enrichment enhances the dominance of grasses over forbs in a temperate steppe ecosystem
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DOI：
10.5194/bg-8-2341-2011
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发表时间：
2011-08
期刊：
影响因子：
4.9
通讯作者：
L. Song;X. Bao;Xuejun Liu;Y. Zhang;P. Christie;A. Fangmeier;Fusuo Zhang
中科院分区：
文献类型：
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作者：
L. Song;X. Bao;Xuejun Liu;Y. Zhang;P. Christie;A. Fangmeier;Fusuo Zhang
抽象的。中国草原是广阔的自然生态系统，占国土总面积的40%，对氮沉降非常敏感。 2005年和2010年在内蒙古多伦进行了六种施氮量（0、30、60、120、240和480 kg N ha−1 yr−1）的田间试验，以确定施氮对温带草原生态系统的影响。根据物种生活型，样地中的优势植物物种分为禾本科和杂草两大类。氮沉降增强，即使比环境氮沉降（16 kg N ha−1 yr−1）高出 30 kg N ha−1 yr−1，也会导致物种丰富度下降。草的覆盖度随着施氮量的增加而增加，但其物种丰富度在施氮处理之间表现出微弱的变化。线性回归分析显示，随着氮沉降的增加，物种丰富度和杂草覆盖度都急剧下降（p
Abstract. Chinese grasslands are extensive natural ecosystems that comprise 40 % of the total land area of the country and are sensitive to N deposition. A field experiment with six N rates (0, 30, 60, 120, 240, and 480 kg N ha−1 yr−1) was conducted at Duolun, Inner Mongolia, during 2005 and 2010 to identify some effects of N addition on a temperate steppe ecosystem. The dominant plant species in the plots were divided into two categories, grasses and forbs, on the basis of species life forms. Enhanced N deposition, even as little as 30 kg N ha−1 yr−1 above ambient N deposition (16 kg N ha−1 yr−1), led to a decline in species richness. The cover of grasses increased with N addition rate but their species richness showed a weak change across N treatments. Both species richness and cover of forbs declined strongly with increasing N deposition as shown by linear regression analysis (p