Quantitative evaluation of ecological cumulative effect in mining area using a pixel-based time series model of ecosystem service value

Abstract

Study on the ecological cumulative effect (ECE) in mining area is an effective way to understand the impact of long-term coal mining on the ecological environment. However, the existing quantitative models to evaluate the ECE in mining area focus more on region-wide features, static analysis and multi-temporal comparison with numerical results, but less on the spatial heterogeneity, dynamic changes trajectory and visual mapping of ECE. In order to fill this gap, we have proposed a pixel-based time series model of ecosystem service value (ESV) to quantify the ECE in mining area and reveal its spatial distribution, heterogeneity and dynamic process. The model was constructed from three dimensions, namely space, time and element, which were analyzed from pixel scale, the whole research period and the perspective of ESV respectively. Taking Yanzhou coalfield as the study area, from 1987 to 2016 as the time span, the model was used to analyze the ECE. The study results showed that: 1) it could display the detail about each pixel’s spatio-temporal change of ESV credibly by dynamic equivalent factor method based on time-series remote sensing (RS), with equivalent factor rectified by remote sensing-based ecological index (RSEI) and modified normalized difference water index (MNDWI) pixel by pixel. 2) The pixel-based time series model of ESV showed a good performance in reflecting the spatial distribution and heterogeneity of ECE, revealing the direction and extent of accumulation, and achieving the dynamic evaluation of ECE in the time dimension. 3) The change of ecosystem service value cumulant (COESVC) in Yanzhou coalfield decreased by 644.49 million RMB, showing obviously negative ECE. The areas with negative ECE were mainly distributed outside the area above mining faces, while that with positive ECE mostly appeared in waterlogged areas, especially those within the area above mining faces. The evaluation result of ECE could be used in decision-making for improving ecological quality and developing coal mining strategies. This paper may also offer an idea and method for dynamic and quantitative evaluation of the ECE in mining and similar area by time-series Landsat-based RS.