J Plant Ecol ›› 2023, Vol. 16 ›› Issue (1): rtac088.DOI: 10.1093/jpe/rtac088

• Research Articles •    

Seasonal droughts drive up carbon gain in a subtropical forest

Brian Njoroge1,2,3, Yuelin Li1,2,3,*, Dennis Otieno4,5, Shizhong Liu1,2,3, Simin Wei1,2,3, Ze Meng1,2, Qianmei Zhang1,2, Deqiang Zhang1,2, Juxiu Liu1,2,3, Guowei Chu1,2, Fasih Ullah Haider1,2 and John Tenhunen5   

  1. 1 Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China, 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China, 3 University of Chinese Academy of Sciences, Beijing 100039, China, 4 Department of Botany, Jaramogi Oginga Odinga University of Science and Technology, Bondo 210-40601, Kenya, 5 Department of Plant Ecology, University of Bayreuth, 95440 Bayreuth, Germany

    *Corresponding author. E-mail: yuelin@scib.ac.cn, yuelin.li@uni-bayreuth.de
  • Received:2022-06-07 Revised:2022-07-23 Accepted:2022-08-20 Online:2022-09-07 Published:2023-02-01


The study aimed to show that droughts are increasing in frequency and intensity in the Dinghushan Biosphere Reserve and to illustrate the effects of seasonal droughts on carbon gain in a subtropical forest. This is in response to the threat posed by increased droughts due to global climate change. We used four drought indices to accurately determine periods of drought and periods of increased precipitation. Thereafter, the measured eddy flux and soil moisture content data collected from 2003 to 2014 were compared between the droughts and wet periods to determine drought impacts on the ecosystem carbon gain. Drought accounted for about 20% of the 12-year study period, with the highest drought events and severity occurring between 2012 and 2013. The average annual precipitation and air temperature during the study period were 1404.57 ± 43.2 mm and 22.65 ± 0.1 °C, respectively, showing a decrease of 523 mm in precipitation and an increase of 2.55 °C in temperature, compared with the 30-year records (1990–2020). Contrary to most published data for most forest ecosystems globally, Dinghushan Biosphere Reserve recorded significant carbon gain during 60% of the drought period.

Key words: drought, climate change, carbon gain, Dinghushan Biosphere Reserve, eddy flux

本研究旨在表明处于南亚热带的鼎湖山生物圈保护区的干旱频率和强度正在增加,并说明季节性干旱对亚热带森林碳积累的影响。这是为了应对全球气候变化导致的干旱加剧所带来的威胁开展的一项研究。我们使干旱指数(标准化降水指数、标准降水蒸散发指数、降水距平百分率及自校准帕尔默干旱指数)准确确定干旱期和降水量增加期。此后,将2003至2014年(12年)监测采集的实测涡动通量和土壤含水量数据在干旱期和湿润期之间进行比较,以确定干旱对生态系统碳积累的影响。在本研究所选择的12年期间,干旱的发生时间约占比20%,最强干旱事件和严重程度发生于2012至2013年。研究期间的年平均降水量和气温分别为1404.57 ± 43.2 mm和22.65 ± 0.1 °C,与30年记录(1990–2020)相比较,年降水量减少量可达523 mm,而气温则增加了2.55 °C。与全球针对大多数森林生态系统研究所发表的数据呈相反趋势,处于中国南亚热带区域的鼎湖山生物圈保护区在60%的干旱期内所监测的森林生态系统记录到显著的碳积累趋势,说明季节性干旱驱动了森林的碳积累。

关键词: 干旱, 气候变化, 碳积累, 鼎湖山生物圈保护区, 涡动通量