Changes in vegetation cover and driving factors in the Loess Plateau from 2001 to 2022

Understanding the mechanisms by which vegetation-change trends respond to their driving factors is important for environmental resource management, particularly in ecologically fragile regions. In this study, vegetation cover on the Loess Plateau is analyzed in terms of the normalized difference vegetation index (NDVI), using precipitation and temperature as the climatic factors. Land use, nighttime light remote sensing, and population density data are integrated to establish a human activity intensity (HAI) index. Trend analysis and partial derivatives revealed the spatiotemporal characteristics of NDVI changes on the Loess Plateau from 2001 to 2022 in different ecological subregions and on the regional scale. The precipitation, temperature, and HAI contributions to the NDVI changes were quantified and the dominant factors driving the vegetation cover changes were explored. The key findings reveal that (1) the NDVI has been steadily increasing at 0.0049 per year, indicating good vegetation recovery on the Loess Plateau over the past 22 years. (2) The precipitation, temperature, and HAI contributed (on average) 0.0947%·a-1, 0.0643%·a-1, and 0.1083%·a-1 to the NDVI changes, respectively, in the study area. (3) The NDVI increase on the Loess Plateau is primarily driven by the combined effects of climate and human activity, with climate factors playing a secondary role. Monitoring the impact of climate change on vegetation and strengthening the management of human activities are essential for promoting sustainable ecological restoration and environmental protection strategies on the Loess Plateau.