Preference heterogeneity and scale heterogeneity in urban river restoration: A comparative study between Brussels and Guangzhou using discrete choice experiments

The discrete choice experiment approach has been widely applied in developed nations to examine individual preferences and associated heterogeneity regarding the provision of ecosystem services, and thereby a wealth of empirical evidence has been generated. Knowledge about how to inform and benefit the DCE studies in developing countries remains limited due to a lack of direct cross-country comparisons between developed and transitional nations. Using two duplicate DCE surveys executed in Brussels (the capital city of Belgium) and Guangzhou (the capital city of Guangdong province in southern China), where local municipal governments are intending to restore heavily modified and polluted river stretches in densely-populated urban settings, this study provides an in-depth analysis and comparison between two groups of respondents' preferences and influencing factors. The DCE data are analyzed using an advanced generalized multinomial logit model with attribute interactions to explore and account for observed preference heterogeneity and unobserved scale heterogeneity simultaneously, and also latent class models to highlight the presence of divergent preferences within the sample and construct the linkage between preference heterogeneity and individual characteristics, including respondents' perceptions of urban river's ecosystem services and socio-economic characteristics. While fairly similar preference heterogeneity regarding various attributes are found between respondents from the two cities, there exists a highly significant scale heterogeneity and hence a large degree of uncertainty amongst Guangzhou respondents when making their choice decisions in a DCE exercise. Another significant finding shared by respondents from the two cities is that those who could not appreciate urban river's ecosystem services adequately were not in favor of moving away from the status quo. Contributing to the growing literature that recognizes and explores residents' preference heterogeneity, as well as the scale heterogeneity in environmental and ecological goods, this comparative study provides information for policy-makers and practitioners for optimizing strategies to restore impaired urban river ecosystems.