Response of Vegetation Dynamics in the Three-North Region of China to Climate and Human Activities from 1982 to 2018

Abstract

To tackle ecological problems, many ecological restoration projects have been implemented in northern China. Identifying the drivers of vegetation change is critical for continued ecological engineering. In this study, three typical ecological reserves in the Three-North Shelter Forest Program Region (TNSFR) were selected to identify their vegetation development characteristics and driving mechanisms using the normalized difference vegetation index (NDVI), climate factors, and land use data. The results show that (1) NDVIs increased in the range of human activities of all of the three ecological reserves, indicating an obvious effect of the vegetation restoration projects. (2) In the planting period, vegetation restoration was mainly correlated with human activities. After entering the tending period, the impact of climate changes on vegetation dynamics was enhanced. (3) Temperature and precipitation provided approximate driving effects on vegetation dynamics in Region I, while vegetation dynamics in Regions II and III were more strongly correlated with precipitation. (4) The proportion of areas with ecological measures exceeded 50% in all three regions. In short, ecological projects in the three ecological reserves dominated the quantity of vegetation restoration, while climate changes influenced the quality of vegetation restoration.