J Plant Ecol ›› 2021, Vol. 14 ›› Issue (5): 843-853.DOI: 10.1093/jpe/rtab036

• Research Articles • Previous Articles     Next Articles

Recent greening of grasslands in northern China driven by increasing precipitation

Kai Di1 , Zhongmin Hu1, *, Mei Wang1, *, Ruochen Cao1, Minqi Liang1, Genan Wu2,3, Ruru Chen2,3, Guangcun Hao4,5 and Yaolong Zhao1   

  1. 1 School of Geography, South China Normal University, Shipai Campus, Guangzhou 510631, China, 2 Synthesis Research Center of Chinese Ecosystem Research Network, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China, 3 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100101, China, 4 China Communications Construction Co. Ltd., Fourth Harbor Engineering Institute Co., Ltd., Guangzhou 510230, China, 5 China Communications Construction Co. Ltd., Key Laboratory of Environmental Protection & Safety of Communication Foundation Engineering, Guangzhou 510230, China

    *Corresponding author. E-mail: huzm@m.scnu.edu.cn (Z.H.); wangmei619@126.com (M.W.)
  • Received:2020-09-04 Revised:2020-11-06 Accepted:2021-03-05 Online:2021-05-04 Published:2021-10-01

Abstract:

Aims

Recent warmer and wetter climate in northern China remains a hot topic in recent years, yet its effect on vegetation growth has not been fully understood. This study investigated the temporal change of vegetation cover and its correlations with climatic variables from 1982 to 2018 for grasslands in northern China. Our aim is to clarify whether the warmer and wetter climate in recent years drives the greening of the vegetation in this region.

Methods

We investigated the temporal dynamic of vegetation normalized difference vegetation index (NDVI) and its driving forces based on long time-series data. Piecewise regression was used to examine whether there was a turning point of the trend of NDVI and climatic variables. Pearson correlation analyses were conducted to quantify the relationship between NDVI and climatic factors. Stepwise multivariable regression was used to quantify the contributions of climate variables to the temporal variations in NDVI.

Important Findings

We found a turning point of NDVI trend in 2008, with GIMMS NDVI indicating a slight increase of 0.00022 yr−1 during 1982–2008 to an increase of 0.002 yr−1 for GIMMS NDVI during 2008–2015 and 0.0018 yr−1 for MODIS NDVI during 2008–2018. Precipitation was the predominant driver, and air temperature and vapor pressure deficit exerted a minor impact on the temporal dynamics of NDVI. Overall, our results suggest a turning point of NDVI trend, and that recent warmer and wetter climate has caused vegetation greening, which provides insights for better predicting the vegetation cover in this region under changing climate.

Key words: plant growth, temporal dynamics, turning point, trend change, climate change

摘要:
近年中国北方草地变绿受降水增加的驱动
中国北方的暖湿化是近期的热点话题,然而其对植被生长的影响仍不清楚。本研究基于长时间序列(1982–2018年)数据,研究了归一化植被指数(NDVI)的时间动态及其气候驱动因子之间的关系,以探索近年来气候的暖湿化是否会导致该区植被变绿。我们采用分段回归探测了NDVI的变化趋势是否存在转变点,用Pearson相关分析描述了植被指数与气候因子的关系。最后,采用逐步多元回归方法研究了气候因子对NDVI时间变化的贡献率。研究结果表明,NDVI时间变化趋势的转变点出现在2008年,GIMMS NDVI在1982–2008年略有增加,上升速率为0.00022 yr−1,在2008–2015年上升速率达到0.002 yr−1,MODIS NDVI在2008–2018年上升速率为0.0018 yr−1。降水是NDVI变化的主要驱动因子,气温和饱和水汽压差(VPD)对NDVI的变化影响较小。总体看来,NDVI时间序列变化趋势存在转变点,并且近期气候的暖湿化主导了中国北方草地植被变绿,这为今后更好地预测该地区气候变化下的植被覆盖变化提供了依据。

关键词: 植被生长, 气候动态, 转变点, 变化趋势, 气候变化