The Interactive Relationships between the Tourism-Transportation-Ecological Environment System of Provinces along the ‘Silk Road Economic Belt’ in China

Taking nine provinces and cities along the ‘Silk Road Economic Belt’ as an example, this paper constructs an evaluation index system of the coupling coordination degree of the tourism–transportation–ecological environment system (TTE system), analyzes the spatial–temporal evolution and regional differences of the coupling coordination level of the TTE system from 2004 to 2016 using the mean square error index model and the scissor difference model, and uses the EKC curve model to further verify the interactive relationship between the tourism economy and the ecological environment. The results show the following. (1) The comprehensive evaluation values of the tourism subsystem and transportation subsystem are on an overall upward trend and the comprehensive evaluation value of the ecological environment subsystem is in constant flux. (2) The coupling coordination degree of the TTE system generally develops in a good coordination direction, but the conversion rate of the coupling coordination degree of each province is different. (3) Regarding the north–south region divergence, the degree of coupling and coordination within the region is “strong in the south and weak in the north”. (4) The tourism subsystem and the transportation subsystem are interdependent and mutually restrictive. (5) There is a strong correlation between tourism, economic growth, and environmental quality, but in most provinces, the relationship between them does not accord with the inverted U-shaped environmental Kuznets curve.