Spatiotemporal Evolution and Driving Mechanism of Fractional Vegetation Coverage in the Yangtze River Delta

Abstract

An in-depth exploration of fractional vegetation coverage (FVC) changes and driving mechanisms in the Yangtze River Delta (YRD) is crucial for maintaining regional ecological health and achieving sustainable development. We therefore calculate FVC in the YRD from 2012 to 2021 based on MODIS NDVI data, and analyze its spatiotemporal evolution. Multiple regression residual analysis and geographic detector model were used along with various auxiliary data to further explore its driving mechanisms in a hierarchical manner. Finally, the Hurst index was used to forecast future trends in FVC. The results show that: 1) Significant changes in FVC occurred around 2016, rapidly declining at a rate of 8.9×10-3a-1 from 2012 to 2016, followed by fluctuating growth at a rate of 5.2×10-3a-1 thereafter. 2) Although the overall development of FVC in the YRD tends toward stability, the fluctuation was pronounced in the Taihu Lake Basin. Improvement areas were mainly concentrated on both sides of the Yangtze River in the central part of the YRD and in the southern mountainous region. Degraded areas were concentrated in cities north of the Huai River. 3) Dynamic changes in FVC were primarily driven by a combination of climate and human activities, whereas spatial heterogeneity was mainly driven by factors such as elevation, slope, and landform type. The improvement in the explanatory power of anthropogenic factors for spatial heterogeneity when combined with natural factors was significant.

Keywords

• Driving mechanism
• fractional vegetation coverage
• spatiotemporal evolution
• Yangtze River Delta