基于最小数据集-聚类分析的高寒草甸退化综合评价

Comprehensive Evaluation of Alpine Meadow Degradation Based on the Smallest Data Set and Cluster Analysis

【目的】综合植被‐土壤属性,构建适用于评价高寒草甸退化的指标体系及分级标准,以期为高寒草甸生态恢复提供基础数据和理论支撑。【方法】以若尔盖花湖周边高寒草甸为对象,综合文献、标准和主成分分析法构建植被‐土壤综合评价指标体系。利用熵权法、主成分分析法和综合指数法获取草甸质量指数,基于系统聚类和自然断点法划分的草甸质量等级及样地的植被-土壤属性,确定草甸退化程度。【结果】基于最小数据集的高寒草甸退化综合评价指标体系共有8个指标,包括植被盖度、地上生物量、可食性植物生物量、容重、有机质、速效钾、β‐1,4‐葡萄糖苷酶和脲酶。其中,土壤有机质、可食性植物生物量和β‐1,4‐葡萄糖苷酶综合权重分别为0.232、0.215和0.206,对草甸质量的影响大于其余指标。根据评价指标计算的草甸质量指数(MQI)为0.142~0.713,基于该指数可将草甸质量划分为4个等级,分别为未退化草甸(MQI≥0.36)、轻度退化草甸(0.28≤MQI<0.36)、中度退化草甸(0.20≤MQI<0.28)和重度退化草甸(MQI<0.20),最后拟定高寒草甸退化综合评价指标体系及其分级标准。研究区高寒草甸以轻、中度退化为主,其退化面积占比约71.34%。【结论】构建的高寒草甸退化评价体系合理且可操作性较强,能为小区域高寒草甸进行定量的植被-土壤系统退化监测和评价提供技术参考。

【Objective】In this study,we have developed an index system and classification criteria suitable for evaluating the degradation of alpine meadow based on vegetation-soil properties.Our aim is to provide fundamental data and theoretical support for the ecological restoration of alpine meadows.【Method】In this study,we selected the alpine meadow around the Huahu Lake on the Zoige Plateau as our research subject.Through the integration of literature,standards,and principal component analysis,we developed a comprehensive evaluation index system for vegetation-soil.Additionally,we employed entropy weight,principal component analysis,and comprehensive index methods to derive the meadow quality index.Subsequently,we utilized systematic clustering and the natural breakpoint method to categorize the levels of meadow quality and vegetation-soil properties of the sample plots,enabling us to determine the degree of meadow degradation.【Result】The comprehensive index system for evaluating alpine meadow degradation based on a minimum data set comprised 8 indexes,including vegetation coverage,above-ground biomass,edible plant biomass,soil bulk density,soil organic matter,soil available potassium,β-1,4-glucosidase,and urease.Additionally,the comprehensive weights assigned to soil organic matter,edible plant biomass,andβ-1,4-glucosidase were 0.232,0.215,and 0.206,respecdoitively.These parameters exhibited a more pronounced impact on the quality of alpine meadows when compared to other indicators.The meadow quality index(MQI),computed from the assessment indicators,ranged between 0.142 and 0.713.Using this index,the meadow quality was categorized into four grades:non-degraded(MQI≥0.36),lightly degraded(0.28≤MQI<0.36),moderately degraded(0.20≤MQI<0.28),and heavily degraded meadow(MQI<0.20).Subsequently,a comprehensive evaluation index system and classification criteria for alpine meadow degradation were proposed.The alpine meadows in the study area were predominantly lightly or moderately degraded,encompassing approximately 71.34%of the total area.【Conclusion】The developed index system for evaluating the degradation of alpine meadow is both reasonable and operable,providing technical guidance for the quantitative monitoring and evaluation of vegetation-soil system degradation in small areas.