Spatial-temporal collaborative relation among ecological footprint depth/size and economic development in Chengyu urban agglomeration.

This is the first attempt to simultaneously apply an improved three-dimensional ecological (EF) model and multivariate spatial-temporal collaborative relation model for evaluating the inter-regional ecological sustainability. Capital flow consumption and capital stock depletion can be tracked based on identification of variations in ecological footprint size (EF) and depth (EF). Results display an unsustainable natural capital stock utilization in Chengyu urban agglomeration, especially in Neijiang, Chengdu, and Deyang with EF higher than 35. There exists an obvious regional complementarity between EF and EF, where cities with rich resources (or poor resources) are generally characterized as high EF and low EF (or low EF and high EF). The EF is slightly lower than traditional ecological footprint in value owing to its more concerns of intergenerational fairness and intrageneration fairness. Moreover, the spatial-temporal binary collaborative relation among EF, EF, and GDP is generally higher than 0.6 with a medium level. Their temporal multivariate collaborative relation mostly lies in the intervals [0.30, 0.50] with an annual change rate of 10.22%, while slight variations exist in their spatial multivariate collaborative relation. GDP has a significant impact on the temporal collaborative relation of EF and EF in Dazhou, Leshan, Luzhou, Mianyang, and Nanchong. There are slight impacts of EF on the temporal collaborative relation of EF and GDP; meanwhile, GDP has a less effect on the spatial collaborative relation of EF and EF. Findings can provide a reference for the coordinated development of social economy and ecological environment.