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Acta Prataculturae Sinica ›› 2024, Vol. 33 ›› Issue (11): 30-45.DOI: 10.11686/cyxb2023484

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Initial effects of short-term warming on the productivity of alpine degraded grassland in northern Tibet during the restoration process

Hao SHI1(), Cai-hong YANG1(), Fei XIA3(), Jun-qiang WANG2,3, Wei WEI3, Jing-long WANG3, Yun-yin XUE2, Shai-kun ZHENG1, Hao-yang WU2, Lin-ling RAN2, Shuang YAN2, Xiao-min JIANG1   

  1. 1.College of Forestry,Gansu Agricultural University,Lanzhou 730070,China
    2.Institute of Ecology,China West Normal University,Nanchong 637002,China
    3.Institute of Pratacultural Science,Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa 850000,China
  • Received:2023-12-18 Revised:2024-01-03 Online:2024-11-20 Published:2024-09-09
  • Contact: Cai-hong YANG,Fei XIA

Abstract:

Climate warming is expected to affect the productivity of alpine grassland in northern Tibet, and this may affect the grassland restoration process. The aim of this study, therefore, was to determine the effects of a short-term temperature increase on the productivity of alpine grassland during restoration. Natural restored grassland (NR), no-tillage replanted grassland (S), and tilled replanted grassland (TS), with native heavily degraded grassland as the control (CK), were subjected to a warming treatment using the open top chamber method. The changes in the plant community, biomass, and species diversity in response to this short-term temperature increase were determined. The results showed that: 1) Warming increased the surface soil temperature by an average of 1.34 ℃ and decreased the soil moisture content by an average of 4.18%. 2) After short-term warming, the plant community cover increased significantly (P<0.05) and the height of plant community decreased significantly (P<0.05); the biomass of vegetation in CK transferred to the underground plant parts, the biomass of vegetation in NR, S, and TS shifted to the aboveground plant parts; and the aboveground biomass decreased significantly in TS (P<0.05). 3) Short-term warming decreased the aboveground biomass and importance value of grasses (P<0.05) but increased the aboveground biomass and importance value of forbs (P<0.05). 4) In CK, warming significantly increased the species richness index, Shannon-Wiener index, and Simpson index by 17.65%, 18.54%, and 11.52%, respectively (P<0.05). In S, the warming treatment resulted in a significant decrease in the Pielou index (P<0.05). 5) After short-term warming, the above-ground biomass showed a highly significant negative correlation with the species diversity index (P<0.01); however, the below-ground biomass showed no significant correlation with the species diversity index or community characteristics. In conclusion, short-term warming had a certain positive effect on the recovery of the species diversity in native heavily degraded grassland in northern Tibet. Short-term warming restored the productivity of naturally restored grassland and no-tillage replanted grassland, but suppressed the growth and reduced the productivity of tilled replanted grassland.

Key words: simulated warming, alpine grassland, productivity, biomass, species diversity