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In-depth research on the spatial and temporal evolution of ecosystem service trade-offs and synergistic relationships, scientific identification of ecosystem service bundles, and the main factors affecting the spatial differentiation of ecosystem service bundle provisioning are crucial to enhancing the overall benefits of regional ecosystem services and human well-being. Based on the assessment of the Guangdong–Hong Kong–Macao Greater Bay Area ecosystem service functional system, we combined the correlation analysis method, hierarchical clustering method, and principal component analysis to analyze the trade-offs/synergistic relationships of 11 indicators contained in four major ecosystem service categories of the Guangdong–Hong Kong–Macao Greater Bay Area and explored the study of ecosystem service bundle identification and clustering spatial differentiation. The results of this study showed the following: (1) Between 2000 and 2018, Regulating and Supporting services showed a decreasing trend while provisioning and cultural services showed an increasing trend. Human interference affected the spatial differentiation of ecosystem services provision; the provision of individual ecosystem services was more random, but the geospatial distribution showed a certain degree of regularity. (2) The intrinsic connection of ecosystem services is continuously strengthened, and the other four ecosystem services except industrial products in the provisioning services easily produce synergistic relationships with regulating and supporting services, while industrial products, leisure and recreation, scientific research and education, and other ecosystem services are more likely to produce a trade-off relationship between them. The correspondence among ecosystem service trade-offs, synergistic relationships, and cold/hot spots is not uniform due to spatial scales. (3) The method of combining socio-economic statistics and the InVEST model can identify similar ecosystem service bundle classifications, but there are differences in the performance of some of the roles at different study scales and in different study areas. (4) For complex urban-natural ecosystem services, the classified ecosystem service bundles have broad similarities. The development of high-density city clusters depends on the coordinated development of the population, resources, environment, society, and economy of each city in the region. [ABSTRACT FROM AUTHOR]

Clonorchiasis is an important food-borne parasitic disease caused by Clonorchis sinensis infection. The evaluation of long-term cost-effectiveness of control strategies is important for disease control and prevention. The present study aimed to assess the cost-effectiveness of the three recommended strategies (i.e., WHO, Chinese and Guangdong strategies) and different combinations of commonly used measures (i.e., preventive chemotherapy, information, education, and communication (IEC) and environmental improvement) on clonorchiasis. The study area, Fusha town in Guangdong Province, was a typical high endemic area in China. The analysis was based on a multi-group transmission model of C. sinensis infection. We set the intervention duration for 10 years and post-intervention period for 50 years. The corresponding costs and DALYs were estimated. Strategies with incremental cost-effectiveness ratios (ICERs) less than 1/5 of the willingness-to-pay threshold were identified as highly cost-effective strategies. The optimal control strategy was obtained using the next best comparator method. The ICERs of Guangdong strategy were $172 (95% CI: $143-$230) US for praziquantel and $106 (95% CI: $85-$143) US for albendazole, suggesting the highest cost-effectiveness among the three recommended strategies. For praziquantel, 470 sets of control strategies were identified as highly cost-effective strategies for achieving infection control (prevalence<5%). The optimal strategy consisted of chemotherapy targeted on at-risk population, IEC and environmental improvement, with coverages all being 100%, and with the ICER of $202 (95% CI: $168-$271) US. The results for transmission control (prevalence<1%) and albendazole were obtained with the same procedures. The findings may help to develop control policies for C. sinensis infection in high endemic areas. Moreover, the method adopted is applicable for assessment of optimal strategies in other endemic areas. Author summary: Clonorchiasis, a food-borne trematodiases, affects millions of people in Asia. Highly cost-effective control strategies are critical for its control. Previous studies considering the economic evaluation of control strategies were rare, mostly based on interventions in practical, and not capable of evaluating long-term cost-effectiveness of strategies with possible combinations of control measures or under various coverages. Based on a dynamic, multi-group transmission model, we simulated different control strategies in a high clonorchiasis endemic area, and evaluated their cost-effectiveness. Among the three recommended strategies (i.e., WHO, Chinese and Guangdong strategies), the Guangdong strategy was the most cost-effective. For praziquantel, 470 sets of control strategies were identified as highly cost-effective strategies for achieving infection control (prevalence<5%) among the strategies of possible combinations of the three common measures (i.e., preventive chemotherapy, information, education, and communication (IEC) and environmental modification). The optimal strategy consisted of chemotherapy targeted on at-risk population, IEC and environmental improvement, with coverages all being 100%. The results for transmission control (prevalence<1%) and albendazole were obtained with the same procedures. The numerical results may help to develop control strategies for C. sinensis infection in high endemic areas. The methodology is applicable for other different endemic areas. [ABSTRACT FROM AUTHOR]