NDVI Dynamics and Its Response to Climate Change and Reforestation in Northern China

Xingna Lin,Ronny Berndtsson,Xiongwen Chen,Jianzhi Niu,Xinxiao Yu,Linus Zhang

doi:10.3390/rs12244138

Abstract

Vegetation is an important component of the terrestrial ecosystem that plays an essential role in the exchange of water and energy in climate and biogeochemical cycles. This study investigated the spatiotemporal variation of normalized difference vegetation index (NDVI) in northern China using the GIMMS-MODIS NDVI during 1982–2018. We explored the dominant drivers of NDVI change using regression analyses. Results show that the regional average NDVI for northern China increased at a rate of 0.001 year−1. NDVI improved and degraded area corresponded to 36.1% and 9.7% of the total investigated area, respectively. Climate drivers were responsible for NDVI change in 46.2% of the study area, and the regional average NDVI trend in the region where the dominant drivers were temperature (T), precipitation (P), and the combination of precipitation and temperature (P&T), increased at a rate of 0.0028, 0.0027, and 0.0056 year−1, respectively. We conclude that P has positive dominant effects on NDVI in the subregion VIAiia, VIAiic, VIAiib, VIAib of temperate grassland region, and VIIBiia of temperate desert region in northern China. T has positive dominant effects on NDVI in the alpine vegetation region of Qinghai Tibet Plateau. NDVI is negatively dominated by T in the subregion VIIBiib, VIIBib, VIIAi, and VIIBi of temperate desert regions. Human activities affect NDVI directly by reforestation, especially in Shaanxi, Shanxi, and Hebei provinces.

Highlights

Vegetation is an important component of terrestrial ecosystems [1] that plays an essential role in the exchange of water and energy, biogeochemical cycles [2], climate conditions, and carbon sequestration by linking soil, atmosphere, and water [3]
During the period 1982–2018, the regional average annual normalized difference vegetation index (NDVI) for the whole northern China fluctuated between 0.392 and 0.463, and it increased at a rate of 0.001 year−1
The research studied the spatiotemporal variation of NDVI in northern China and its drivers, and explored the effects of different drivers on NDVI

Summary

Introduction

Vegetation is an important component of terrestrial ecosystems [1] that plays an essential role in the exchange of water and energy, biogeochemical cycles [2], climate conditions, and carbon sequestration by linking soil, atmosphere, and water [3]. In the process of global warming, monitoring of vegetation and its driving factors are important for a better understanding of global change ecology [4,5]. For large-scale monitoring of vegetation, remote sensing images have been utilized widely. The normalized difference vegetation index (NDVI), derived from GIMMS or MODIS, is utilized widely to study vegetation dynamics due to its high correlation with photosynthetic capacity, leaf area index, biomass, and net primary productivity [6]. Annual and seasonal NDVI dynamics have been studied to detect vegetation dynamics globally and regionally [1]. Driving factors of vegetation/NDVI dynamics include climate factors, such as climate change, and human activities, such as reforestation [7]

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Conclusion