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Arid Land Geography ›› 2021, Vol. 44 ›› Issue (1): 229-239.doi: 10.12118/j.issn.1000–6060.2021.01.24

• Biology and Pedology • Previous Articles     Next Articles

Characteristics and environmental implications of dung pollen assemblages of grazing livestock in alpine meadow in the eastern Qinghai-Tibetan Plateau

DUAN Ronglei1,2(),HOU Guangliang1,WEI Haicheng2(),XU Qinghai3,GAO Jingyi1   

  1. 1. College of Geographical Science, Qinghai Normal University Qinghai Province Key Laboratory of Physical Geography and Environmental Process, Qinghai Normal University; Xining 810008, Qinghai, China
    2. Key Laboratory of Comprehensive and Highly Efficient Utilization of Sale Lake Resources, Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lake, Chinese Academy of Sciences, Xining 810008, Qinghai, China
    3. College of Resources and Environment and Hebei Key Laboratory of Environmental Change and Ecological Construction, Hebei Normal University, Shijiazhuang 050016, Hebei, China
  • Received:2020-03-24 Revised:2020-05-20 Online:2021-01-25 Published:2021-03-09
  • Contact: Haicheng WEI E-mail:rlduan25@163.com;hcwei@isl.ac.cn

Abstract:

The Qinghai-Tibetan Plateau is an important area of alpine meadow pasture and livestock husbandry in China. The impact of grazing activity on the vegetation and ecology in the Qinghai-Tibetan Plateau has attracted widespread attention from many scholars. To study the impact of grazing activity on regional vegetation, we collected 49 dung samples of grazing livestock (comprising 30 yak dung, 11 horse dung, and 8 sheep dung) from the typical alpine meadow in the eastern Qinghai-Tibetan Plateau. Our study area extended from 34°30′08″- 35°06′28″N, 101°30′57″-101°42′04″E, with elevations ranging between 3456 m and 3815 m. The vegetation communities in the sampling sites were also investigated during the field work. Principal component analysis was used to explore the characteristics of the different dung samples and pollen taxa. Meanwhile, the pollen assemblage of the dung samples was compared with the topsoil pollen assemblages in the study area to examine the selective grazing characteristics of the different livestock in the Qinghai-Tibetan Plateau. These results indicate that the pollen assemblages in the three types of livestock’s dung samples were dominated by Cyperaceae, Poaceae, Gentianaceae, and Ranunculaceae, generally reflecting the characteristics of the regional plant communities. However, there are some differences in the feeding habits of the three kinds of grazing livestock: the feeding rates of yaks and horses to Poaceae and Thalictrum species are lower than those of sheep, and those to Gentianaceae, Compositae, and Artemisia species are significantly higher than those of sheep. In addition, cereal Poaceae pollen appeared in the dung samples, reflecting the behavior of the local residents in cultivating oats to raise their livestock. Grazing livestock directly affects the vegetation community structure of alpine meadow through selective feeding of the dominant plant species of Cyperaceae and Poaceae. The comparison of the pollen assemblages of the dung and topsoil samples in the study area indicates that the contents of Cyperaceae, Polygonaceae, Ranunculaceae, Taraxacum, and Artemisia were similar. However, the contents of Poaceae and Gentianaceae in the dung samples were higher than those in the topsoil samples, and the content of Aster in the topsoil samples was higher than that in dung samples, suggesting the selective feeding characteristics of the grazing livestock. Additionally, the content of arboreal pollen, including Betula, Pinus, Picea, and Hippophae, in the topsoil samples was higher than those in the dung samples, indicating that the dung pollen assemblages could better reflect the characteristics of the local vegetation community. This study provides a new research approach for assessing the grazing habits of livestock and impact of grazing activity on regional vegetation in the Qinghai-Tibetan Plateau. Additionally, the study of pollen assemblages in modern dung samples provides an important reference for the fossil dung pollen assemblages in the archaeological sites to infer the past vegetation and ancient humans’ subsistence strategy on the Qinghai-Tibetan Plateau.

Key words: dung pollen, principal component analysis (PCA), grazing livestock, paleo-vegetation, Qinghai-Tibetan Plateau