Spatial−temporal pattern and influencing factors of vegetation coverage in the northern agro−pastoral ecotone in China from 2000 to 2022

This paper is the result of ecological geological survey engineering.

Objectives This paper systematically studied the spatial and temporal distribution characteristics and change trends of vegetation cover in the northern agro-pastoral ecotone in China from 2000 to 2022, and scientifically revealed the multiple influencing factors and mechanisms of vegetation cover change, which can provide data and theoretical support to carry out the evaluation of ecological quality and the investigation and assessment of important ecological space in this area.

Methods Taking the northern agro-pastoral ecotone as the research area, different types of data were collected, including natural factors (elevation, meteorological data, etc.), human factors (land−use practices, etc.) and MODIS−NDVI remote sensing images. GIS spatial analysis methods and mathematical and statistical methods such as trend analysis, Mann−Kendall non−parametric test and correlation analysis were applied to analyze the spatial-temporal characteristics and influencing factors of vegetation coverage in the agro-pastoral ecotone of northern China from 2000 to 2022.

Results (1) The average vegetation cover in the northern agro-pastoral ecotone increased by 0.0093/a year from 2000 to 2022. The overall vegetation cover showed a spatial distribution characteristic of "high in the east and low in the west". (2) From 2000 to 2022, the spatial−temporal trends of FVC in the study area was mainly increasing, with the proportion of the area with highly significant and significantly increasing trends being 60.33% and 10.14%. (3) In terms of terrain, when the elevation of the study area was under 2500 m or above 4000 m, the vegetation coverage gradually decreased with the increase of elevation. When the elevation was between 2500 and 4000 m, the vegetation coverage gradually increased with the elevation increasing. In addition, the vegetation cover gradually increases when the slope is between 0° and 45°. In terms of meteorology, vegetation cover was positively correlated with average temperature and negatively correlated with the drought index. In terms of land use, the overall change of vegetation cover was affected by the transformation of quantity, mode and structure of land use types such as grassland, forest land and arable land in different years in the study area.

Conclusions The vegetation coverage in the study area showed an increasing trend, and the ecological quality increased obviously. The vegetation cover in the study area had a strong correlation with a variety of influencing factors, such as natural factors (topography, meteorology) and human factors (land use).