Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (11): 1350-1363.DOI: 10.17521/cjpe.2022.0069

• Research Articles • Previous Articles     Next Articles

Effects of grazing on species composition and community structure of shrub tussock in subtropical karst mountains, southwest China

HUANG Kuai-Kuai1,2, HU Gang1, PANG Qing-Ling1,2, ZHANG Bei1,2, HE Ye-Yong1,2, HU Cong1, XU Chao-Hao1, ZHANG Zhong-Hua1,*()   

  1. 1College of Environmental and Life Sciences, Nanning Normal University, Nanning 530100, China
    2School of Geography and Planning, Nanning Normal University, Nanning 530100, China
  • Received:2022-02-21 Accepted:2022-06-29 Online:2022-11-20 Published:2022-07-04
  • Contact: *ZHANG Zhong-Hua(
  • Supported by:
    The Natural Science Foundation of Guangxi(2021GXNSFFA196005);The Natural Science Foundation of Guangxi(2021GXNSFAA196024);The Natural Science Foundation of Guangxi(2017GXNSFDA198003);The National Natural Science Foundation of China(31760128);The National Natural Science Foundation of China(31960275)


Aims The karst ecosystem in southwest China is fragile and easily degraded by disturbance. However, the process and mechanism of karst shrub tussock responding to grazing disturbance in the early stage of restoration are still poorly understood.
Methods In this study, four grazing intensity of heavy, moderate, light and none grazing were selected in shrub tussock communities in karst mountains of Mashan County, Guangxi. Species composition and community structure of the vegetation were investigated, and their responses to grazing were further analyzed.
Important findings The results show that: (1) There are 272 species of vascular plants in the sample plots, belonging to 77 families and 200 genera. Poaceae, Asteraceae, Fabaceae and Verbenaceae are the dominant families. With the increase of grazing intensity, the number of families, genera and species in the shrub layer decreased monotonously. However, in the herb layer a single peak was shown in the light grazing area. (2) The increase in grazing intensity did not significantly change the dominant species, but the important values of species changed. For example, the important values of shrub Vitex negundo, herbaceous invasive species Chromolaena odorata and Bidens pilosa, increased with the increase of grazing intensity. (3) Non-metric multi-dimensional scaling (NMDS) analysis showed that grazing led to the vegetation homogenization of shrub layer, and the species composition of most plots tended to be similar, but the species composition of the same grazing gradient also had great differences. Species in the shrub layer were mainly affected by grazing intensity and rock exposure rate, while species in the herb layer were affected by terrain and soil factors such as altitude, soil organic matter content, soil pH, in addition to grazing intensity. (4) Community height, coverage of shrub layer and aboveground biomass decreased significantly with the increase of grazing intensity. The response of community structure in shrub layer to grazing intensity was more obvious than that in herb layer, which may be related to the preference of goats to eat shrubs. Overall, the increase in grazing disturbance intensity will drive the simplification, sparseness and dwarfing of the species composition and community structure of shrub tussock, thereby significantly reducing aboveground biomass and enhancing the potential risk of vegetation degradation in karst mountains, and further hindering natural recovery of karst ecosystem.

Key words: grazing, karst mountain, species composition, community structure, aboveground biomass, vegetation degradation