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.

Spatiotemporal Variations of Vegetation and Its Response to Climate Change and Human Activities in Arid Areas—A Case Study of the Shule River Basin, Northwestern China*

“…Observations of the NDVI via remote sensing satellites are susceptible to various factors that may affect data quality. The annual maximum method is commonly employed [49]. This method utilizes the following calculation formula:…”

“…It is commonly assumed that FVC is affected by the combined impact of two factors: human activities and climate variability [26,27,29,35,58,[60][61][62][63]. The response of vegetation conditions to temperature and precipitation is often nonlinear [41].…”

“…The response of vegetation conditions to temperature and precipitation is often nonlinear [41]. The residual analysis method calculates the relative contributions of climate change and human activities to attribute better the observed vegetation changes to climate change and human activities [60,64].…”

Ecological Risks Arising for the Regional Water Resources in Inner Mongolia due to a Large-scale Afforestation Project

“…(1) Trend analysis was used to identify areas with significant increase in NDVI in Inner Mongolia from 2000 to 2020. Trend analysis is a linear regression analysis of time-dependent variables [27,28]. The constantly changing properties of the vegetation may be reflected in the trend of the change in NDVI for each grid by applying linear trend analysis.…”

Quantitative Assessment of the Impact of the Three-North Shelter Forest Program on Vegetation Net Primary Productivity over the Past Two Decades and Its Environmental Benefits in China

“…They found that the impact of population density and GDP on vegetation NPP was more significant than that of climatic factors such as precipitation [29]. In recent years, societal policies such as ecological engineering have played an increasingly significant role in influencing terrestrial vegetation [30]. Cai et al (2023) employed the RF method to identify the primary drivers of changes in NPP in China, attributing them mainly to human activities, particularly afforestation and other ecological engineering endeavors [31].…”