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Arid Land Geography ›› 2022, Vol. 45 ›› Issue (2): 557-565.doi: 10.12118/j.issn.1000–6060.2021.255

• Biology and Environment • Previous Articles     Next Articles

Sensitive response of vegetation phenology to seasonal drought in the Loess Plateau

JI Zhenxia1(),HOU Qingqing2,PEI Tingting1,3(),CHEN Ying1,3,XIE Baopeng3,WU Huawu4,5   

  1. 1. College of Resources and Environment, Gansu Agricultural University, Lanzhou 730070, Gansu, China
    2. College of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, Gansu, China
    3. College of Management, Gansu Agricultural University, Lanzhou 730070, Gansu, China
    4. Key Laboratory of Grassland Ecosystem (Gansu Agricultural University), Ministry of Education, Lanzhou 730070, Gansu, China
    5. Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, Jiangsu, China
  • Received:2021-06-04 Revised:2021-09-02 Online:2022-03-25 Published:2022-04-02
  • Contact: Tingting PEI E-mail:986164054@qq.com;825629198@qq.com

Abstract:

Under the background of global warming, the increasing frequency and intensity of drought events significantly change the vegetation diversity in terrestrial ecosystems. Vegetation productivity, carbon storage, and the carbon cycle in terrestrial ecosystems are deeply affected by vegetation phenology. However, there are few studies on the effects of seasonal drought on different vegetation phenology due to the inherent complexity, uncertainty of drought, and differences in the resistance and resilience of different vegetation to drought. Therefore, based on the normalized differential vegetation index, landuse cover, and monthly temperature and monthly precipitation data, this study calculated the start of the season (SOS), end of the season (EOS), and standardized precipitation evapotranspiration index (SPEI) of vegetation on the Loess Plateau. Additionally, it analyzed the response of vegetation phenology changes to seasonal SPEI using the Ridge regression analysis method from 2001 to 2018. The results are as follows. (1) The vegetation SOS was delayed by the intensification of drought in summer and autumn of last year, whereas the SOS of vegetation was advanced by the weakening of drought in winter and spring of the same year. SPEI in the winter at the beginning of the year is more likely to delay vegetation EOS than SPEI in the spring and fall of the same year. An intensification of the summer drought could cause vegetation to stop growing earlier. (2) The EOS and SOS of vegetation showed obvious spatial heterogeneity in response to seasonal SPEI. The SOS of vegetation in the Loess Plateau will be advanced when the drought degree decreases at the beginning of winter in Qinghai. The intensification of drought in summer would lead to the premature end of most vegetation growth on the Loess Plateau. The response of most vegetation to drought at the end of the growth period was weaker than in other seasons. (3) The SOS of shrub was delayed, and the SOS of grassland was advanced due to SPEI in different seasons, and shrub was more susceptible to drought than forest and grassland. Droughts in winter at the beginning of the year have the greatest impact on the SOS of grassland than other seasons. Meanwhile, the growth of forests, shrubs, and grassland will end earlier with drought intensities in summer. This study revealed the response law of vegetation phenology to seasonal drought in the Loess Plateau. It provided a scientific basis for vegetation response to water stress and ecological environment protection.

Key words: vegetation phenology, seasonal drought, sensitivity response, the Loess plateau