Linking the Ecological and Economic Values of Wetlands: A Case Study of the Wetlands of Moreton Bay

Abstract

Three approaches for assessing non-market values (direct linkage models, revealed preference and stated preference models) are reviewed with respect to their ability to capture ecological value. An alternative biophysical approach, namely energy analysis, is also considered. The review suggests that it may be possible to measure ecological value using the contingent valuation method. The role of information in preference formation and willingness to pay bids is then investigated along with a number of other issues that need to be resolved before using the contingent valuation method. The wetlands of the case study area, Moreton Bay, Australia exhibit both ecological and economic values. The wetlands contribute approximately one-third of primary productivity in the Bay, provide habitat for a wide range of dependent species (including internationally recognised migratory wader birds) and have a diverse fauna with a relatively large number of endemic species. Economic values of the wetlands include both direct and indirect use values (for example, fishing, recreation, water quality improvements and storm buffering) and non-use values. Non-use values include the value in preserving the environment for future generations (bequest value) and the existence of vulnerable animals such as turtles and dugongs, which one may never expect to see. If consumers are willing to pay to preserve these animals, this is also a valid economic value. The economic technique of contingent valuation is tested to determine if it is possible to capture ecological value by providing respondents, selected by random sample, to a survey with the relevant information. A case study is undertaken in Moreton Bay to determine respondents' willingness to pay to improve water quality and hence protect the wetlands. To test the effects of differing types information, four different versions of the survey were sent to four groups of 500 respondents. Case A provided no extra information so it could be used as a control. Case B included information about the ecological values of the wetlands of Moreton Bay. Case C provided information about the economic use values of the wetlands in the Bay including direct and indirect use. Case D provided information about the non-use values of endangered species resident in the Bay that are dependent on the wetlands. The results indicate that the provision of different types of information influences willingness to pay. However, willingness to pay when provided with ecological information is not significantly different from willingness to pay when provided with other information. As it was not possible from the research undertaken to state that the contingent valuation method can capture ecological value, an alternative approach is proposed to link ecological and economic values. It is argued that ecologists and economists need to develop common aims and scales of assessment. Further, communication between the two disciplines can be enhanced through the use of agreed indicator terms. Through an iterative approach it should then be possible to understand the linkages between changes in indicators of ecosystem values and indicators of economic value.