Spatiotemporal Analysis and Control of Landscape Eco-Security at the Urban Fringe in Shrinking Resource Cities: A Case Study in Daqing, China

A practice study of land and water comprehensive remediation in urban-rural fringe-with Sichuan River Shaanxi Province, Northwest China, as an example

Urban-rural fringe area (URFa) is an active and expansive region, and its environment is complex and frangible. Previous studies have focused on the landscape spatial pattern changes, the spatial-temporal variability of soil pollutants and the land management and policy issues, etc., but it is lack of the practice study of land and water comprehensive remediation in URFa. This article is taking the Sichuan River, a typical URFa, as an example. Based on field investigation and lab tests, the main characteristic form of the URFa and land and water comprehensive remediation measures are summarized in this paper. The results show that it is feasible to turn wasteland, low-efficiency land, and old deserted beach into farm land, residential land, and ecological land by comprehensive land improvement. For the farm land reconstruction, the texture is an important indicator. The content of soil organic matter (SOM), carbon, nitrogen, and phosphorus has increased after remediation. For the SOM, 58.3% are more than 10.0 g·kg^-1, and 79.2% are more than 8.0 g·kg^-1. For the frequent dry-off and polluted low flow river channels in URFa, the river bottom consolidation and water purification is the important measures. The water quality meets IV standard of the "Environmental Quality Standards for Surface Water" (GB3838-2002) (State EPA of China, 2002) by pollution treatment after remediation, and water volume keeps balance. The findings of this study are expected to provide support for better construction practices in arid and semiarid area in China and for the improvement of the ecological environment in URFa.

Conflict or coordination? Assessment of coordinated development between socioeconomic and ecological environment in resource-based cities: evidence from Sichuan province of China

The relationship between socioeconomic and ecological environment becomes a significant factor influencing the regional sustainable development of resource-based cities (RBCs); how to coordinate the relationship between socioeconomic growth and ecological environment is the key problem to achieve sustainable development goals of RBCs. A comprehensive evaluation indicator system was constructed to research the coupling coordination level of RBCs in this paper; the dynamic DM model and the CCD model were adopted to measure the comprehensive level of the coupling coordination degree between socioeconomic and ecological environment of the 9 resource-based cities from 2008 to 2018 in Sichuan province. The results showed that the coupling coordination level was not ideal. Only two cities were located to the moderate coordination, and other cities were located to the primary coordination or tiny coordination. In addition, there was a significant difference between SE and EE, and the comprehensive evaluation score of SE was lower than that of EE in eight RBCs, which accounts for 88.89%. Based on this, we analyzed the reasons for the backward development of the socioeconomic system of the resource-based cities in order to provide relevant references for the transformation of the RBCs. Finally, the policy suggestions for the sustainable development of different types of RBCs were provided, involving improving the policy and financial support for enterprise transformation, promoting high-new technology to improve production efficiency, strengthening government guidance on industrial layout, stabilizing employment, and improving the social security system. This study offers a model of China's experience that might be beneficial for achieving sustainable development goals (SGDs) of other cities and countries.