Analysis of Spatial and Temporal Changes and Driving Forces of Ecological Environment Quality in Tuojiang River Basin Based on RSEI Improved Modeling

Abstract

[Objective] Tuojiang River Basin is facing serious ecological and environmental problems such as soil erosion, water environment pollution and soil erosion. It is of great significance to carry out the evaluation of the ecological and environmental quality of this basin in order to promote the ecological environmental protection of the upper reaches of the Yangtze River and the high-quality sustainable development of the basin's socio-economy. [Methods] Based on the Google Earth Engine platform, Landsat remote sensing images from 2000 to 2020 were selected to construct an ecological environment quality evaluation model with NDVI, WET, LST, NDBSI, and AI indices, and the coefficient of variation, one-way linear regression, and spatial autocorrelation analysis methods were used to analyze the spatial and temporal evolution pattern of ecological environment quality in the watershed, and to detect the driving force using the optimal parameter Geographic Detector Model(OPGD). [Results] (1) During the period of 2000—2020, the multi-year average value of ecological environmental quality in the Tuojiang River Basin is 0.66, and the grade is mainly good, accounting for 63.01%. The ecological environment quality in the surrounding districts and counties of Chengdu, Neijiang, Zigong, Luzhou and other towns and regions is poor, showing a spatial distribution pattern of low north-south and high middle. (2) The ecological environment quality of the Tuojiang River Basin is generally on a declining trend, and the trend of deterioration of ecological environment quality is significant, with the ratio of slightly degraded and significantly degraded areas being 19.75% and 5.88%. The urbanized areas with high population density and high level of socio-economic development are dominated by higher fluctuations in ecological environment quality, accounting for 18.15%. (3) The global autocorrelation Moran index of Tuojiang River Basin during 20 years ranged from 0.769 to 0.870, which was mainly distributed in the first and third quadrants, and the ranges of local autocorrelation high-high agglomerations and low-low agglomerations showed significant changes over time, with obvious fragmentation of the landscape patches. (4) The OPGD results show that land use type, slope, elevation, and nighttime lighting are the main drivers of ecological quality change in the watershed, population density, temperature, and GDP are secondary drivers, and precipitation and slope orientation factors are less influential. Land use type interacted with other factors to enhance the influence on the change of ecological environment quality in the watershed. [Conclusion] The improved remote sensing eco-index model provides a new method for regional ecological environment quality evaluation, and the results of the study provide a reference for ecological environment protection.

Keywords

• ecological environment quality
• improved remote sensing ecological index model
• spatio-temporal analysis
• driving forces
• the geographic detector model
• tuojiang river basin