Temporal stability of river ecological restoration based on the assessment of Contingent Valuation Method: A case study of Shanghai urban river

Abstract

Whether the assessment results of Contingent Valuation Method (CVM) have temporal stability is an important issue in examining the reliability of CVM findings, and also, is critical to decide whether CVM can be applied to evaluate the ecosystem services value in China. Taking the ecological restoration along the Caohejing River in Shanghai as a case, three CVM survey schemes with one month apart and two years apart were designed. Then, 426, 498, and 200 questionnaires in these surveys were comparatively analyzed, respectively. The mean values of the willingness to pay (WTP) from the three surveys were 14. 2, 14. 1, and 18. 0 RMB, and the median values were 5, 5, and 10 RMB, respectively. With the comparison of the WTP distribution and the main statistics, the analysis of the factors affecting the WTP, and the test of the significances of temporal variables, it was found that the CVM results from the surveys with one month apart had temporal stability, while those from the surveys with two years apart presented definite difference.