摘要:受气候暖干化和旅游干扰等因素影响，滇西北高寒草甸出现了明显的退化趋势。为探究滇西北高寒草甸退化过程中植物地上形态和生产力的变化规律，在香格里拉市依据游径宽度确定了3个草甸退化梯度：一级退化（R1），二级退化（R2）和对照（CK），并于2018年7月进行野外调查，获取禾本科、莎草科和杂类草3个功能群植物的株高、开展度、叶长、叶宽、叶片长宽比等地上形态指标及植株地上生物量数据，构建各功能群植物生存状态指数（Vegetation living state，VLS）。结果表明：1）禾本科植物的植株高度、植株开展度、叶片长度和叶片长宽比随退化程度增加而减小。莎草科植物的植株高度、叶片长度和叶片长宽比随退化程度增加而减小。杂类草植物的所有的地上形态指标均随退化程度增加而减小；2）随退化程度增加，3个功能群植物的地上生物量均显著下降（P < 0.05）；3）随退化程度增加，禾本科、莎草科和杂类草植物的VLS均减小。退化梯度上3个功能群植物的VLS排序也发生了变化：CK样地中植物VLS的排序为杂类草 > 莎草科 > 禾本科；R1和R2样地中，莎草科植物的VLS显著高于禾本科和杂类草，但禾本科和杂类草植物之间的VLS没有显著差异；4）草甸植物VLS与植物地上生物量之间的线性回归关系随退化程度增加而减弱。研究表明不同功能群植物地上形态的差异性变化可能增加滇西北退化高寒草甸植物生产力预测的不确定性。



Abstract:There is an obvious degradation tendency of alpine meadows in Northwestern Yunnan Province (NYP)because of climate change and disturbance of tourism activities. In order to identify the changes of aboveground morphological traits and biomass of plants in the process of meadow degradation in NYP, this study specified three degradation levels, i.e., degradation level 1 (R1), degradation level 2 (R2) and control check (CK), according to the width of tourism-caused paths. A field survey was conducted to obtain the data of height, lateral spread, leaf length, leaf width, blade aspect ratio and aboveground biomass of Gramineae, Cyperaceae and Forbs in late July 2018. A vegetation living state index (VLS) was constructed based on aboveground morphological traits indexes to describe a synthetic state of plants. The results showed that: 1) the height, lateral spread, leaf length and blade aspect ratio of Gramineae decreased along the degradation gradient. The height, leaf length and blade aspect ratio of Cyperaceae decreased along the degradation gradient. All of the five aboveground morphological traits of Forbs decreased along the degradation gradient. 2) Aboveground biomass of Gramineae, Cyperaceae and Forbs decreased along the degradation gradient. 3) The VLS of Gramineae, Cyperaceae and Forbs decreased along the degradation gradient. The VLS order of different functional groups in CK was Forbs > Cyperaceae > Gramineae. The VLS of Cyperaceae was higher than the VLS of Gramineae and Forbs in both R1 and R2. 4) The linear regression relationship between the VLS and aboveground biomass weakened along with degradation gradients. This study suggests that the variation of aboveground morphological traits among different functional groups may augment the uncertainty of the prediction of aboveground biomass in degraded alpine meadows in NYP.





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