植物生态学报 ›› 2022, Vol. 46 ›› Issue (11): 1350-1363.DOI: 10.17521/cjpe.2022.0069

• 研究论文 • 上一篇    下一篇

放牧对中国亚热带喀斯特山地灌草丛物种组成与群落结构的影响

黄侩侩1,2, 胡刚1, 庞庆玲1,2, 张贝1,2, 何业涌1,2, 胡聪1, 徐超昊1, 张忠华1,*()   

  1. 1南宁师范大学环境与生命科学学院, 南宁 530100
    2南宁师范大学地理科学与规划学院, 南宁 530100
  • 收稿日期:2022-02-21 接受日期:2022-06-29 出版日期:2022-11-20 发布日期:2022-07-04
  • 通讯作者: *张忠华(gxtczzh@126.com)
  • 基金资助:
    广西自然科学基金(2021GXNSFFA196005);广西自然科学基金(2021GXNSFAA196024);广西自然科学基金(2017GXNSFDA198003);国家自然科学基金(31760128);国家自然科学基金(31960275)

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(gxtczzh@126.com)
  • 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)

摘要:

中国西南喀斯特生态系统较为脆弱, 易因干扰而退化, 然而处于植被恢复早期的喀斯特灌草丛对放牧干扰的响应过程及其机制仍知之甚少。该研究以广西马山县的亚热带喀斯特山地灌草丛为对象, 选取重牧、中牧、轻牧和无牧4个放牧强度的群落设置样方并进行调查, 从而分析喀斯特山地灌草丛的物种组成与群落结构对放牧强度的响应。主要结果: (1)样地中有维管植物272种, 隶属77科200属, 禾本科、菊科、豆科和马鞭草科是优势类群。随着放牧强度的增加, 灌木层的科、属、种数量单调递减, 草本层物种数单峰变化, 峰值出现于轻牧区; (2)放牧强度增加并未使优势种发生明显更迭, 但重要值会发生变化, 如灌木黄荆(Vitex negundo)以及草本入侵种飞机草(Chromolaena odorata)、鬼针草(Bidens pilosa)的重要值会随放牧强度增加而增加; (3)非度量多维尺度排序(NMDS)分析表明, 放牧致使灌木层物种趋于同质化, 多数样方间的物种组成趋于相似, 但同一放牧强度中的物种组成也存在较大差异; 灌木层物种受放牧强度和岩石裸露率的影响最为明显, 而草本层植物除受放牧强度影响外, 还受海拔、土壤有机质含量、pH等因子影响; (4)群落高度、灌木层盖度和地上生物量随放牧强度的增加呈现明显降低趋势, 且灌木层在群落结构方面的响应较草本层明显, 这可能与山羊喜食灌木有关。总的来看, 放牧强度的增加会驱使灌草丛物种组成与群落结构简单化、稀疏化和矮小化, 从而显著降低地上生物量并增加喀斯特山地植被退化的潜在风险, 阻碍喀斯特生态系统的自然恢复。

关键词: 放牧, 喀斯特山地, 物种组成, 群落结构, 地上生物量, 植被退化

Abstract:

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