阿拉善草地健康评价的CVOR指数

CVOR index for health evaluation of Alashan grazing land

依据草原发生学原理,确定了阿拉善草地生态系统健康评价的参照系统,用当地水热因子重建参照系统的初级生产力和植被组成等主要特征,作为评价现有草地健康的参照指标。根据多维生态位理论以及地境要素之间的定量关系,用土壤有机碳作为评价草地基况的重要指标。在地境—牧草界面,围绕生产力形成及其分布格局这一关键生态过程,建立草地健康评价的CVOR综合指数和测算模型,并应用于阿拉善草地的健康评价。结果表明,CVOR能够定量放牧压力和封育对草地健康的作用,避免各单项指标容易造成的误差,揭示VOR不能完全反映的草地健康信息。认为,生态系统健康更多地依赖于管理水平,CVOR具有综合、简单、准确、适用的特点。

Models of healthy ecosystems for the Alashan grassland were built based on principles of grassland origin and development, and their main characteristics were quantified using local rainfall, heat and other climatic factors, which were used as indictaors to evaluate grassland health. According to multidimensional niche theory and the relationship between soil organic carbon (SOC) and other site factors, SOC was used as a principal index for condition (C) evaluation of grassland. For the site-herbage interface, the CVOR index was created based on formation of herbage productivity and its species distribution pattern, and was used to measure the health of Alashan grassland. The results indicate that CVOR can quantify the effects of grazing intensity and exclusion of livestock on grassland health, avoid errors which often come from evaluation using single indexes including C, V (vigor), O (organization) or R (resilience), and unveil grassland health information which VOR cannot fully reflect. It was suggested that ecosystem health is closely dependent on management rather than natural causes, and that CVOR is a comprehensive, simple, accurate and applicable index to measure it.