Journal of Plant Ecology ›› 2022, Vol. 15 ›› Issue (4): 818-828.DOI: 10.1093/jpe/rtab118

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  • 收稿日期:2020-12-01 修回日期:2021-02-10 接受日期:2021-10-03 出版日期:2022-08-01 发布日期:2022-08-29

Impact of grazing on germination trait selection in an alpine grassland on the Tibet Plateau

Yang Liu1,†, Kun Liu1, *,†, Zhilong Zhang2, Shiting Zhang1, Carol C. Baskin3,4, Jerry M. Baskin3,Ting Liang1, Haiyan Bu1, Shuxia Li1, Tingting Zhang1, Xianliang Cui5 and Sa Xiao1   

  1. 1 State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730020, China, 2 Department of Chemistry and Life Science, Gansu Normal College for Nationalities, Hezuo 74700, China, 3 Department of Biology, University of Kentucky, Lexington, KY 40506, USA, 4 Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40506, USA, 5 School of Biological and Chemical Science, Puer University, Puer 665000, China

    *Corresponding author. E-mail: liukun@lzu.edu.cn
    These authors contributed equally to this work.
  • Received:2020-12-01 Revised:2021-02-10 Accepted:2021-10-03 Online:2022-08-01 Published:2022-08-29

摘要: 放牧对青藏高原高寒草地种子萌发性状选择的影响
以前的研究表明放牧能够引起草地生物与非生物环境的显著变化,但这种变化影响草地群落对种子萌发特征的选择机制尚不清楚。因此,我们旨在回答:放牧是否对草地群落中萌发特征的组成和多样性产生显著影响。我们在实验室检测了研究草地群落内主要物种种子的萌发特性,并比较了这些植物在放牧和非放牧草地上的表现。在此基础上,比较了放牧草地和非放牧草地的各萌发性状的群落加权平均值和萌发性状多样性,从而了解放牧草地和非放牧草地是否存在不同的萌发性状结构。研究结果表明,在物种水平上,放牧和非放牧草地各物种的多度变化与物种的萌发性状无显著关系。但在群落水平上,与非放牧草地相比,放牧草地的物种普遍具有较高的种子萌发率;放牧草地种子萌发对变温的正响应显著大于非放牧草地,而且放牧草地种子萌发温度生态位宽度小于非放牧草地。与非放牧草地相比,放牧草地种子萌发性状多样性增加,萌发性状均匀度降低。放牧可以改变微生境,从而通过环境过滤改变草地群落对萌发性状的选择,导致草地群落的萌发性状于放牧前后在群落水平上存 在显著差异。


关键词: 高寒草地, 生物多样性, 萌发特征选择, 放牧, 青藏高原

Abstract:

Previous studies indicated that grazing can cause significant changes in abiotic and biotic environment in grassland. However, how these changes impact germination trait selection in grassland has not been well studied. Thus, we aimed to explore whether grazing can significantly change germination trait diversity and composition of grasslands community. We measured the germination traits of species in the laboratory, and compared their performance in grazed and nongrazed grasslands. Then, we compared the community-weighted means of germination traits and functional diversity of grazed and nongrazed grasslands based on these germination traits to know whether grazed and nongrazed grasslands differed in their germination trait structures. At the species level, we found that the changes of abundance in grazed and nongrazed grasslands were not related to species’ germination traits. However, at the community level, compared with nongrazed grasslands, species in the grazed grasslands generally exhibited a higher seed germination percentage. Moreover, seed germination response in grazed grasslands was more positively related to alternating temperature than in nongrazed grasslands, and breadth of the germination temperature niche was narrower in grazed than in nongrazed grasslands. Compared with nongrazed grasslands, seed germination trait diversity was increased and germination trait evenness decreased in grazed grasslands. Grazing can change microhabitat conditions, thereby changing germination trait selection by environmental filtering, resulting in a significant difference in germinate trait composition at the community level.

Key words: alpine grassland, biodiversity, germination trait selection, grazing, Tibet Plateau