Study On Double Counting In Wetland Ecosystem Services Evaluation—Based On The Network Matrix Model

Wetland ecosystem services value accounting is an important part of the statistical accounting of ecological resources assets, through the acounting scholars could understand the current situation and development potential of social economic development, meanwhile, it can help us to develop a reasonable development plan. In the evaluation of wetland ecosystem services, the problem of double counting is an important factor to affect the evaluation results.In this paper, the Shuangtai estuarine wetlands are selected as the research sample,through the established process of the network matrix model of ecosystem services, we try to explore the existence of the evaluation of the double counting. The main conclusions are as follows:1. In this paper, we found that the uncertainty of the wetland ecosystem service of the weights, the complexity of the relation between service and "beneficiary" and the dynamic of wetland ecological system were the main reasons cause to the problem of the double counting.Wetland ecosystem is very complex, and it is a cycle process that the ecosystem services are delivered from the process of transfer to the generation of value to the new generation. Use the static evaluation method to evaluation the value of the wetland ecosystem service, the accuracy of the results of the study would have a greater negative effect. Through the analysis of these three main reasons, based on the analysis of the weight of the wetland ecosystem services, this paper established the network matrix model in order to study the problem of double counting.2. In this study, the static value and dynamic value are introduced into the wetland ecosystem service evaluation, and combine it with the change of land use changed in the Shuangtai estuary wetland and consider the social economic development and the human demand for ecosystem services as the important factors to analysis the theoretical use value and the actual use value weight of wetland ecosystem. The actual use value of the ecosystem services of the Shuangtai estuary wetland is only 69% of the theoretical value,that means in the evaluation of the overall services value, we have to pay attention to the weight ratio reallycarefully.What’s more, because of the different social development stages and the different needs of the "beneficiaries" to the ecosystem services, the dynamic value can not be assigned by human subjective.3. In this paper, based on the full consideration of the dynamic characteristics of wetland ecosystem, the concept of conversion coefficient was proposed. Based on the conversion coefficient, we established the ecosystem service value evaluation network matrix model. By analyzing the network of the matrix model, get the results with the difference ranging from 12 to 38 percent. Before the whole ecosystem services of estuarine wetland services was evaluated,according to the material evaluation of Shuang tai estuary wetland production service value was verified the network matrix model. After analyzing, Shuangtai estuary wetland ecosystem service value of material production value is 34.54×1019sej/a, and without pre calculation the results of the analysis there are 5.95×1019sej/a diffience, this part is the double counting produced in the evaluation process. The results of the study show that the conversion coefficient and emergy and the network matrix model combined to evaluate the value of wetland ecosystem services can effectively remove the double counting.4. Using the network matrix model to evaluate the value of the ecosystem services of Shuangtai estuary wetland ecosystem in 2012. In 2012, the total value of the ecosystem services in the Shuangtai estuary wetland ecosystem was 595.51×108 yuan, and the amount of the double counting was 99.97×108 yuan, and the double counting elimination rate was about16.8%. In the evaluation process, the key setp was how to change the emergy value into monetary value. In this paper, the emergy-monetary-ratio is 3.74×1010sej/yuan, and it can be compared with other research results. Through the network matrix model and the scientific emergy-monetary-ratio, we can precisely calculated the amount of double counting during the wetland ecosystem services value evaluation process. Meanwhile, the evaluation method system-- the network matrix model--also has some general characteristics, and the evaluation process of the ecosystem services value of the Shuangtai estuarine wetlands can provide reference and basis for other types of ecosystem services value evaluation.5. Due to different economic environment, the wetland ecosystem itself has different location and different attributes, and the ecosystem service value produced by the function of each component in the system is also different, but the double counting in the process of concrete quantization has some general characteristics, and this general characteristics lies in the process of wetland ecosystem services from generation to the value of the "beneficiary". By identifying the three mechanisms of "Split, Feedback, Co-product", we can not only avoid the double counting problem in total value, but also can avoid this problem in a single service.Double counting in evaluation process maybe much smaller than that caused from classification of ecosystem services, but precise quantification of wetland ecosystem services value is essential.