Influence of Geological Environment on Vegetation Coverage in the Eastern Edge of Qinghai-Tibet Plateau: A case study of Mianning

Studying the influence of the geological environment on vegetation coverage is conducive to understand the effect of geological background on ecological environment and promote ecological protection and restoration. The multi-year mean of MODIS-Normalized Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from 2003 to 2018 was selected as the static indicator of vegetation coverage, while the inter-annual variation rate was used as the dynamic index. Pearson correlation statistics were used to reveal the static correlation effects of geological factors, topographic factors, meteorological factors and human activities on vegetation index, as well as the regression relationship between influencing factors and vegetation coverage in spatial scale were obtained by geographic weighted regression (GWR). The results showed that elevation, annual average temperature and annual evapotranspiration were of great significance to the multi-year mean of NDVI / EVI, and the factors such as relief, annual average temperature, annual evapotranspiration and geological complexity performed quite well in explanation for the inter-annual variation rate of NDVI / EVI in Pearson analysis. GWR analysis indicated that the location closed to the fault is conducive to the development and improvement of vegetation. The geological complexity in the middle level was prone to form medium and high vegetation coverage, at the same time, it was in favor of increasing vegetation coverage. When the geological complexity was high, the vegetation coverage was probable to middle and low value. Low altitude, flat terrain and shady slope were favorable for vegetation development and increasing vegetation coverage.