Quantifying impacts of natural and anthropogenic factors on urban ecological quality changes: A multiscale survey in Xi’an, China

Abstract

Over the past decades, cities worldwide have experienced a sharp decline in urban ecological quality (UEQ) due to rapid urbanization accompanied. However, the spatiotemporal dynamics of UEQ and its associated multi-scale impacts of natural and human factors on UEQ changes were still unknown. Thus, based on the Remote Sensing-based Ecological Index, Random Forest regression, and Geographical Detector, taking the downtown area of Xi’an City, China, as an example, we revealed the spatiotemporal dynamics of UEQ from 2000 to 2019 and quantified the impacts of 19 natural and human factors on UEQ changes at 30 scales. Results showed that 1) from 2000 to 2019, the UEQ in the downtown area of Xi'an experienced a sharp decrease at first, and then gradually recovered. But the recovered UEQ was much lower than the lost UEQ, indicating the big loss of UEQ. 2) The identified driving factors had significant impacts on local UEQ within 1300 m. 3) Elevation, temperature, precipitation, slope, and GDP were more important than other factors in impacting UEQ changes. 4) Natural conditions and climate change had the greatest impact on the regional UEQ, followed by social changes and urban built environment. Altogether, our results revealed the complex impacts of natural-anthropogenic factors on UEQ changes, including impact scale, impact strength, and impact interaction, thus can assist local government in optimizing urban planning and improving livable cities.

Keywords

• Urban ecological quality
• RSEI
• Multiscale analysis
• Driving forces
• Random forest
• Geographic detector