Spatiotemporal Evolution and Driving Factors of Habitat Quality in Shanghai from 2000 to 2020

As the world-class core city of the urban agglomeration in the Yangtze River Delta, Shanghai occupies a unique position and holds important significance in the national biodiversity conservation pattern. It is necessary to conduct an assessment of urban habitat quality, and explore the spatial and temporal distribution patterns and potential driving factors, which can provide technical support for optimizing the ecosystem service functions of Shanghai and facilitating the construction of a resilient ecological city under high-density urban settlements scenarios. Based on the land use data from Shanghai in 2000, 2005, 2010, 2015 and 2020, this study evaluated the spatial and temporal evolution characteristics of habitat quality in Shanghai using the InVEST (integrated valuation of ecosystem services and trade-offs) model. Furthermore, the factors influencing the distribution pattern of habitat quality were analyzed by using geographic detectors. The results indicate that: (1) The average habitat quality index in Shanghai fluctuated within the range of 0.270-0.319 over the past two decades, which showed that the regional ecological environment was relatively fragile. The habitat quality index exhibited a decreasing trend, with the rate of decline slowing down over time. (2) The spatial distribution pattern of habitat quality index in Shanghai exhibited a gradually increasing ring radiation from the inner to the outer areas. The inner ring line area displayed the lowest mean value of the habitat quality index with small variations. The mean value of habitat quality index in the middle ring line, outer ring line, and suburban ring line showed a significant downward trend during 2000-2020, which was basically contained after 2015. (3) The construction land index was a critical factor influencing the spatial and temporal evolution of habitat quality in Shanghai. As a direct indicator reflecting the intensity of urban social and economic activities, the night light index had gradually surpassed the population density and NDVI (normalized difference vegetation index) to emerge as the secondary factor influencing the habitat quality of Shanghai in recent years. The two-factor interaction between construction land index and NDVI index enhanced the explanatory degree of habitat quality change in Shanghai, with the interactive effect exhibiting a parabolic change with time. Overall, the urban habitat quality in Shanghai has shown a decreasing trend over the past two decades under the influence of urbanization; however, the rate of decline has slowed down with the intensification of ecological protection measures. Therefore, Shanghai′s urban development should persist in strengthening the protection of critical ecological spaces, reducing urban ecological pressure, promoting the construction of urban ecological spaces predicated on nature-based solutions rather than artificial construction, and exploring a path of biodiversity conservation that suits the characteristics of megacities.