| 摘 要： |
The occurrence of the Wenchuan earthquake caused the degradation of regional ecosystems, including vegetation destruction. However, the post-seismic vegetation recovery and its driving forces on the spatial-temporal scale are still vague, especially in the severely damaged areas (including Wenchuan, Beichuan, Mianzhu, Shifang, Qingchuan, Maoxian, Anzhou, Dujiangyan, Pingwu and Pengzhou). Here, we detected vegetation recovery in the severely damaged areas by using Ensemble Empirical Mode Decomposition (EEMD) to analyze the time series characteristics of the Enhanced Vegetation Index (EVI), and explored the driving effects of climate, land use types, nighttime light, water system, slope, and clay content on vegetation recovery based on Geographically and Temporally Weighted Regression (GTWR) model. The results indicated that the post-seismic vegetation recovery rate increased rapidly (acceleration > 0) but slowed down after 2013. And the areas of best vegetation recovery (EVI increments > 0.1) were distributed in the north of the study area, the Minjiang River Basin, and front fault and central fault of the Longmenshan Fault Zone. While the areas with the worst vegetation recovery (EVI increments < -0.1) were concentrated in the southern high-altitude areas and the Chengdu Plain. Additionally, a process attribution of the driving forces of vegetation recovery indicated that accumulated precipitation and maximum temperature promoted vegetation recovery (regression coefficients > 0), but the impacts weakened after the earthquake, possibly due to the increase of secondary disasters induced by precipitation and the rise in maximum temperature. The impact of cultivated land on vegetation recovery was mostly positive (regression coefficients > 0), which may be related to the implementation of the Grain for Green Project. The nighttime light inhibited vegetation recovery (regression coefficients < 0), which could be closely associated with urbanization. The results indicated that more attention should be paid to the nonlinear variations of post-earthquake vegetation recovery trends, and the effects of climatic and anthropogenic factors on vegetation recovery also should not be underestimated. |
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