Effects of clipping on diversity and above-ground biomass associated with soil fertility on an alpine meadow in the eastern region of the Qinghai-Tibetan Plateau
Effects of clipping on diversity and above-ground biomass associated with soil fertility on an alpine meadow in the eastern region of the Qinghai-Tibetan Plateau
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DOI：
10.1080/00288230709510304
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发表时间：
2007-09-01
影响因子：
1.8
通讯作者：
Du, Guozhen
中科院分区：
文献类型：
--
作者：
Han, Wenwu;Luo, Yanjiang;Du, Guozhen
本研究的目的是验证这样一种假设，即不同的修剪方式对高寒草甸多样性的影响是由于土壤肥力所致。物种丰富度在中等干扰水平时应该是最大的，例如修剪，因为优势被阻止，潜在殖民者的池相对较大。基于干扰假说，我们预测了修剪对物种丰富度、多样性和地上生物量的影响。试验使用的是天然牧草，这是一个随机的完全区组设计，从2001年生长季开始每年投入四个水平的养分。在2004年间，将小块地修剪到距土壤表面2厘米、4厘米和10厘米的残茬高度，并设对照。两次重度刈割处理的物种丰富度平均下降到每样方6种和19种，而未刈割处理和对照小区的平均物种丰富度分别为每样方接受120g肥料和31种。在任何营养水平下，其他剪枝处理不会改变物种丰富度。养分投入最高的样地和重度修剪2次的对照样地物种丰富度下降，但中等水平修剪的样地在所有养分水平下物种丰富度无明显变化。随着养分施用量的增加，土壤速效磷含量显著增加，土壤pH值降低。速效氮和有机质不随养分添加而发生显著变化。刈割条件下，随着养分输入的增加，禾本科植物占主导地位，优势禾本科植物吸收了大量的速效氮和有机质，土壤速效氮变化不大。
The objective of this research was to test the hypothesis that effects of different clipping regimes on diversity on an alpine meadow are due to soil fertility. Species richness should be greatest at an intermediate level of disturbance, e.g., clipping, since dominance is prevented and the pool of potential colonists is relatively large. We predict the effects of clipping on species richness, diversity and above-ground biomass based on the disturbance hypothesis. A natural pasture was used for the experiment that was a randomised complete block design with four levels of nutrient input annually from the 2001 growing season. During 2004, subplots were clipped to stubble heights of 2, 4 and 10 cm above the soil surface, with a control. Species richness declined to an average of 6 and 19 species per quadrat for the treatments that were heavily clipped twice, compared to an average of I I and 31 species per quadrat in the unclipped treatment receiving nutrient input of 120 g of fertiliser/m(2) and control plots, respectively. Species richness was not altered by the other clipping treatments at any nutrient level. Species richness declined in plots with the highest nutrient input and in control plots with heavy clipping twice, but species richness had no obvious changes in those plots receiving the intermediate level clipping at all nutrient levels. Available phosphorus increased significantly with increased nutrient addition, however soil pH decreased. Available nitrogen and organic matter did not change significantly with nutrient addition. The clipping regime contributed to the dominance of graminoids with increased nutrient input, and the dominant graminoids assimilated large amounts of available nitrogen and organic matter, which resulted in the minor changes in available nitrogen in soil.