植物生态学报 ›› 2009, Vol. 33 ›› Issue (6): 1065-1074.DOI: 10.3773/j.issn.1005-264x.2009.06.006

• 研究论文 • 上一篇    下一篇

放牧对内蒙古锡林河流域草地群落植物茎叶生物量资源分配的影响

任海彦, 郑淑霞, 白永飞()   

  1. 中国科学院植物研究所植被与环境变化国家重点实验室,北京 100093
  • 收稿日期:2009-01-01 接受日期:2009-04-27 出版日期:2009-01-01 发布日期:2021-04-29
  • 通讯作者: 白永飞
  • 作者简介:*(yfbai@ibcas.ac.cn)
  • 基金资助:
    国家自然科学基金(30770370);国家科技支撑计划项目(2006BAD26B05)

EFFECTS OF GRAZING ON FOLIAGE BIOMASS ALLOCATION OF GRASSLAND COMMUNITIES IN XILIN RIVER BASIN, INNER MONGOLIA

REN Hai-Yan, ZHENG Shu-Xia, BAI Yong-Fei()   

  1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Received:2009-01-01 Accepted:2009-04-27 Online:2009-01-01 Published:2021-04-29
  • Contact: BAI Yong-Fei

摘要:

以内蒙古锡林河流域沿水分梯度分布的灰脉苔草(Carex appendiculata)、贝加尔针茅(Stipa baicalensis)、羊草(Leymus chinensis)、大针茅(Stipa grandis)、小叶锦鸡儿(Caragana microphylla)和冷蒿(Artemisia frigida) 6个草地群落为对象, 研究了围封禁牧与放牧样地中144个共有植物种的高度、丛幅面积、茎、叶和株(丛)生物量、茎叶比等性状。结果表明: 1)在个体水平上, 放牧样地中植物的生殖枝高度、营养枝高度、丛幅面积、单株(丛)生物量、茎、叶生物量和茎叶比均显著低于围封禁牧样地, 植物在放牧干扰下表现出明显的小型化现象; 2)在群落水平上, 放牧亦显著降低了群落总生物量和茎、叶生物量; 3)过度放牧显著改变了物种的资源分配策略, 使生物量向叶的分配比例增加, 向茎的分配比例减少。资源优先向同化器官分配可能是植物对长期放牧干扰的一种重要适应对策; 4)轻度放牧对物种的资源分配没有显著影响, 单株(丛)生物量和群落茎、叶及总生物量均表现出增加趋势, 这与过度放牧的影响正好相反。过度放牧引起的植物个体小型化改变了生态系统中物种的资源分配策略, 进而对生态系统功能产生重要的影响。

关键词: 放牧, 植物形态性状, 个体小型化, 茎叶比, 资源分配

Abstract:

Aims Our objective is to determine whether 1) characteristics of gazing-induced individual miniaturization differ among plant species and across grassland communities, 2) miniaturized plants have detectable changes in resource allocation, and 3) grazing-induced changes in plant resource allocation affect ecosystem functioning at the plant community level.
Methods Resource allocation of 144 common species from grassland communities, i.e. Carex appendiculata meadow,Stipa baicalensis meadow steppe,Leymus chinensis typical steppe,Stipa grandis typical steppe, Caragana microphylla typical steppe, and Artemisia frigida typical steppe, were investigated along a soil moisture gradient in the Xilin River Basin, Inner Mongolia. We measured morphological traits, including reproductive height, vegetative height, canopy coverage, leaf biomass, stem biomass, stem:leaf ratio, and total biomass of common species at the individual and community levels from paired ungrazed and grazed plots.
Important findings Long-term grazing across the six grassland communities significantly decreased average plant morphological traits such as reproductive height, vegetative height, canopy coverage, leaf biomass, stem biomass, stem:leaf ratio, and total individual biomass in 55%-94% of the common plant species, indicating that individuals tend to miniaturize in response to overgrazing. At the community level, grazing also decreased stem, leaf, and total aboveground biomass. Plant species increased their biomass allocation to leaves, but decreased biomass allocation to stems in grazed plots as compared to the ungrazed plots. This suggests that the increase in resource allocation to photosynthetic organs (e.g., leaves) is likely an important strategy of plants adapting to long-term grazing. In contrast, light grazing increased plant biomass production at both individual and community levels at the meadow steppe. In addition, soil moisture may have important effects on plant resource allocation, with high biomass allocation to stems in wet habitats.

Key words: grazing, morphological traits, individual miniaturization, stem:leaf ratio, resource allocation