Methods for developing a net shape ecological indicator system and assigning rational weights to the indicators
- 海洋环境－已发表论文 
生态指标体系是广泛应用于监测、评估和管理生态系统的一种有效方法和工具。针对不同目的在使用生态指标体系时,构建完整的指标体系结构并合理确定操作指标的权重,是有效利用生态指标体系进行综合评价的2个关键问题。指出目前常用的“树杈状”生态指标体系中存在的不足,提出在保持“树杈状”生态指标体系原有指标和层次结构的基础上,通过弥补指标间的重叠和交叉联系,构建“网状”生态指标体系,体现生态系统的层次性和完整性。同时提出利用权重2次分配法对规则和不规则“网状”生态指标体系中的指标进行权重分配。通过构建生态健康评价指标体系的案例研究,对比“树杈状”和“网状”生态指标体系在结构和指标权重分配上的不同。还针对构建和实际应用“网状”生态指标体系时的2个问题进行了讨论。The complexity of an ecosystem is only seen in parts and its interrelationships are never well understood. Ecological indicators are able to represent, integrate and characterize information embodied in comprehensive data sets when direct measurements cannot be realized. Ecological indicator system (EIS) is normally made up of a number of ecological indicators with certain structure to represent the most important features of the environmental state, the complex ensembles of ecosystem elements and the multiple webs of actions, reactions and interactions. As an effective tool or approach, the ecological indicator system (EIS) is widely used in ecosystem monitoring, assessment and management. While there are many different forms of EIS based on the different purposes for EIS uses, they are all concerned with the following two key steps: structure of the integrated EIS frame and the assignment of rational weights to the ecological indicators. The frame of the EIS should integrally reflect not only the ecological hierarchy, but also the relationships among the complex ensembles of the investigated ecosystem. The status or the importance of an indicator in the EIS will be represented by its weight, which, to some extent, will be determined by the frame of an EIS. This paper reviewed the branch shape ecological indicator system (BEIS) which is in common use at present, and point out its deficiency: (1) the overlapping or intersecting connections of the indicators are often overlooked or simplified. (2) Incorrect weights are assigned to the indicators because of disintegrated representation of the ecosystem complexity. Secondly, a net shape ecological indicator system (NEIS) was presented, including regular NEIS and irregular NEIS. It is developed by adding the overlapping and intersecting relation of the ecological indicators to the BEIS hierarchy frame and thus will better represent the integration and hierarchy of ecosystem. Then a twice assigning weight method (TAW) was demonstrated in both regular NEIS and irregular NEIS. This was used to resolve the problem of assigning the rational weights to NEIS indicators. For further study and comparison of BEIS and NEIS, two indicator systems for ecosystem health assessment were derived from hierarchical ecosystem indicators respectively, using the frames of BEIS and NEIS. The weights of the indicators in BEIS were determined by the AHP and those in NEIS were determined by TAW. It was easy to see the changes of the weights of the indicators in between the BEIS and NEIS. The indicators′ weights in NEIS have a significant trend to the average compared with those in BEIS. Two problems about the NEIS design and application were discussed.