Chin J Plant Ecol ›› 2019, Vol. 43 ›› Issue (10): 853-862.DOI: 10.17521/cjpe.2018.0288

• Research Articles • Previous Articles     Next Articles

Effects of grazing and simulated warming on plant community structure and productivity of alpine grassland in Northern Xizang, China

WU Hong-Bao1,GAO Qing-Zhu1,Ganjurjav Hasbagan1,*(),LI Yu2,YAN Yu-Long3,HU Guo-Zheng1,WANG Xue-Xia1,YAN Jun4,HE Shi-Cheng4   

  1. 1Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    2College of Environment, Beijing Normal University, Beijing 100875, China
    3School of Life Sciences, Inner Mongolia University, Hohhot 0 10021, China
    (4) Nagqu Grassland Station, Nagqu, Xizang 852000, China
  • Received:2018-11-14 Accepted:2019-09-05 Online:2019-10-20 Published:2020-02-24
  • Contact: Ganjurjav Hasbagan
  • Supported by:
    the National Key R&D Program of China(2016YFC0502003);the National Natural Science Foundation of China(31570484);the National Natural Science Foundation of China(31600366);the Central Public-interest Scientific Institution Basal Research Fund(BSRF201713)

Abstract:

Aims Climate change and grazing activities have important effects on species diversity and productivity of grassland ecosystems. The aim of this study is to reveal the differences in responses of species diversity and productivity to warming, grazing and their interactions in an alpine meadow ecosystem. Methods Warming experiment was established in 2011. In 2016, the grazing experiment and the combination of warming and grazing experiment were added. A two-year continuous field experiment was conducted (from 2016 to 2017) and plant community structure, community composition, productivity and species diversity were monitored. Twelve sites were sampled, and were divided into four treatments: control, warming, grazing and the combination of warming and grazing. All sampled species were classified into three functional groups: sedges, grasses and forbs. The species diversity and productivity were sampled in three different treatments. Important findings Results showed that warming and grazing had significant interaction on vegetation height and net primary productivity in alpine grassland. Under grazing treatment, warming had no significant effect on plant height, while warming significantly increased plant height without grazing. Under grazing treatment, the warming effect on net primary productivity significantly differed between 2016 and 2017. In 2016, warming had no significant effect on net primary productivity, while in 2017, warming significantly decreased net primary productivity. Warming and grazing had no significant interaction on species richness, coverage, species important value and species diversity in the alpine meadow. Under the treatments of warming and grazing, the total vegetation coverage decreased, and the proportion of forbs significantly increased. However, no significant effect of warming or grazing was found on species diversity. This study showed that warming and grazing significantly changed the community structure of alpine grassland. Therefore, with the projected climate change in the future, the intensification of grazing activities may lead to the decrease of alpine meadow productivity.

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Key words: warming, grazing, the combination of warming and grazing, species diversity, net primary productivity