Spatio-temporal variation of fractional vegetation cover and its influencing factors in the Yiluo River basin of the middle and lower reaches of the Yellow River from 2002 to 2021

Abstract

【Objective】 To explore the spatio-temporal variation of fractional vegetation coverage (FVC) and its influencing factors in the Yiluo River basin from 2002 to 2021, middle and lower reaches of the Yellow River. 【Method】 In this research, the data of Landsat series satellites in 2002, 2007, 2011, 2016 and 2021 were selected and combined with pixel binary model to extract the vegetation coverage of this basin. The coefficient of variation and linear regression analysis method were used to reveal the spatial-temporal variation of vegetation coverage in this basin. The influence of natural factors and human activity factors on the temporal and spatial changes is analyzed. 【Result】 From 2002 to 2021, the source mountains in the Western and Southern parts of the basin are high FVC areas, while the FVC is low along the river course from West to East and in the central and Northern parts of the basin. The Eastern part is low FVC area. The proportion of high and relatively high FVC area was 65.29%. Medium FVC accounted for 17.66%, low and relatively low coverage accounted for 17.05%. The overall vegetation coverage was high, and the average FVC shows a decreasing trend, and then gradually increases. The FVC of the basin was basically stable in 44.14%, improved area in 32.25%, and slightly degraded area in 17.27%. The proportion of obvious degradation area was 6.34%. The influence degree of natural factors on FVC from high to low is elevation, temperature, precipitation and slope.The FVC increases with the increase of elevation, precipitation and slope, and decreases with the increase of temperature. The positive effect of human activities on FVC was slightly greater than the negative effect, which became an important factor promoting its growth trend. 【Conclusion】 From 2002 to 2021, the vegetation coverage in the Yiluo River Basin was relatively high and gradually increased. Elevation, temperature and precipitation were the main factors affecting its spatial distribution, and human activities promoted its increase.

Keywords

• yiluo river basin
• fractional vegetation cover
• spatial and temporal change
• influencing factors