用能值分析理论修改生物承载力的计算方法——以苏北互花米草生态系统为例

Improving the Computation of Bio-capacity by Emergy Theory:A Case Study of Spartina alterniflora Ecosystem in Northern Jiangsu

首先介绍当前评估生态系统整体效益的两种主流方法:能值分析和生态足迹.并针对生态足迹法中的重要概念——生物承载力进行了分析,在此基础上提出其理论和计算方法上的缺陷.而能值分析方法在理论上比较成熟,其计算方法是一种黑箱式的过程,在一定的程度上可以弥补生态足迹中"空间互斥性"假说的缺陷.随后提出用能值分析理论修改生物承载力的计算方法.最后以苏北的互花米草草滩作为研究对象,利用新旧两种方法进行了一次对比的计算,结果分析发现新方法的结果更具有可信性和适用性.新方法下互花米草种群的每公顷极限生物承载力为5.02 gha,现实生物承载力为3.28gha,这对进一步进行米草的开发提供了有益的信息,并对其他生态系统的开发利用程度提供了有效的评估工具.

This article first introduced two main methods to evaluate the effects of the ecosystems on the whole, emergy analysis and ecology footprint. The article focused on the bio-capacity, an important concept of the ecology footprint method and then the author pointed out the flaws in its theory and its calculating methods as well. Meanwhile, the emergy theory was quite well developed and its calculation methods belonged to one of the dark-boxed process which could make up some of the flaws in the hypothesis of ＂counter space effects＂ in ecology footprint method. Then the authors pointed out a calculating method that was adjusted by using the emergy analysis method. In the end, this article took the fields of Spartina alterniflora in northern Jiangsu Province as an example, and did calculations with the two methods and compared the two results. We found that the new adjusted way derived from emergy analysis was more persuasive and practical. The new method showed that the Spartina alterniflora community had a bio-capacity of 5. 02 gha per acre and the actual bio-capacity is 3.28 gha per acre. This method provided useful information for further exploitation of the Spartina crop and an effective measure in evaluating and exploiting other ecosystems.