Assessing And Mapping The Value Of The Sousa Chinensis In The Pearl River Estuary

The Sousa Chinensis(Chinese White Dolphin)plays a significant and irreplaceable role in the ecosystem of earth,with high values of ecology,scientific education,culture,entertainment and aesthetic.However,evidence shows that the population is on the de-crease and the risk of extinction is going up due to the threat from diverse human activities directly and indirectly.Some of individuals are identified to be injured,even die from underwater blasting in coastal construction projects.Other human activities,such as ag-ricultural and industrial pollution,vessel traffic,and fishing,etc.,also should take the responsibility of potential adverse impact on the Sousa chinensis.Assessing the value of the Sousa chinensis can not only support public with explicit information that this endangered species has a signi:ficant and positive value,but also provide important reference in managing the issues of the dolphin,such as broad-based benefit-cost analysis of species preservation.In order to compare the differences between two kinds of elicitation techniques in estimating the value of the dolphin,this thesis ap-plied both Contingent Valuation Method(CVM)and Choice Experiment(CE)to assess the value in the Pearl River Estuary.In addition,according to a sighting map of the Sousa chinensis investigation as well as previous research results of fishery resources in the Pearl River Estuary,this study established the distribution pattern of the total value of white dolphins in the study area.The research results are shown as follows:(1)This thesis systematically summarizes the theory and methods of economic value assessment of natural resources.On this basis,the thesis chose to estimate the value of the Sousa chinensis by the method of double-bounded dichotomous choice Contingent Valuation(CVM)as well as Choice Experiment(CE).The CE question includes four alternatives for protection of the Sousa chinensis,include:0 protection scheme,low pro-tection scheme,stable protection scheme and intense protection scheme,which contain different preservation targets and related costs.The CVM question is designed based on the stable protection scheme.(2)Questionnaire surveys were conducted in the city of Shenzhen and Zhuhai to elicit individuals' willingness to pay.In the thesis,a total of 1,200 questionnaires were granted in Shenzhen and Zhuhai with 97.3%of them were retrieved.Through the screening of samples,the number of valid samples for CE estimation was 979 and for CVM assess-ment was 985,with valid retrieve rate of 81.58%and 82.08%,respectively.The results from demographic show that the personal characteristics are consistent with the current social and economic status in the cities around the Pearl River Estuary,which can indicate the representativeness of samples.(3)The results from the analysis and comparison of the factors affecting the willing to pay by two approaches show that the factors estimated in two models are different.Age,education level,household monthly income,and the importance of the Sousa chinensis and their support for preservation are the main significant factors influencing respondents'willingness to pay in both two models.Besides,hometown and the recognition degree play a significant role on CE model,while distance variable,housing and the number of fixed income family have a important impact in CVM model.(4)The thesis applies Mixed Logit model and willing to pay model for CE samples and CVM samples respectively to estimate the individuals' mean WTP and the value of dol-phins.The results from Mixed Logit model of CE show that the respondent's marginal willing to pay(WTP)for the stable protection program is 0.061 CNY a dolphin per house-hold per year,which means,the marginal value of the Sousa chinensis is 190,900 CNY.It is estimated that the marginal value under the intense protection scheme is 173,900 CNY,which is lower than the value of stable protection scheme,indicating that the results conform to the law of diminishing marginal utility.In terms of the average WTP,the result from the double-bounded dichotomous choice CVM is 182.76 CNY/household/a,which is slightly larger than the value from CE model(173.72 CNY/household/a).This can demonstrate that the estimations are robust because the results from two models are sim-ilar.Since the number of respondents said 'Yes' to the CVM question is lower than CE,the total value of the dolphin from CVM is reversely lower than result from CE,with 5.24 million yuan and 5.43 million yuan,respectively.Thus,the mean total value is 5.33 mil-lion yuan per year in the Pearl River Estuary.The average value of one Chinese white dolphin estimated by CE and CVM is 217,200 CNY and 209,800 CNY respectively,with the mean value of 213,500 CNY.(5)The thesis analyzes the spatial distribution of total value of the Sousa chinensis in the Pearl River Estuary through assigning the value to the sighting map of the dolphins and the distribution map of the fishery resources in the Pearl River Estuary.It is assumed that the weight of the habitat and food are 0.6 and 0.4,respectively.Then the map of distribution pattern of total value was obtained with the resolution of 1 km2.The results from the mapping shows that the unit value of the study area range from 0.14 to 1.59 CNY/m2,denoting the major spatial heterogeneity of Sousa chinensis in Pearl River Es?tuary.To sum up,this thesis combined both CVM and CE to estimate the value of the Sousa chinensis in Pearl River Estuary and spatialized the total value into grid-based map.The results from this study can help advance the theory and methodology for assessing the value of endangered species and provide valid information for wildlife management de-cision-making,such as the establishment of Marine Protection Area and the design and implementation of the ecological compensation for the Sousa chinensis.