Ramet Recruitment from Different Bud Types along a Grassland Degradation Gradient in Inner Mongolia, China
Ramet Recruitment from Different Bud Types along a Grassland Degradation Gradient in Inner Mongolia, China
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DOI：
10.3161/15052249pje2015.63.1.004
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发表时间：
2015-07
影响因子：
5.2
通讯作者：
J. Qian;C. Busso;Zhengwen Wang;Zhimin Liu
中科院分区：
文献类型：
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作者：
J. Qian;C. Busso;Zhengwen Wang;Zhimin Liu
摘要 由于地下芽库总数和不同芽类型对群落更新的贡献很少被探讨，因此对中国东北（内蒙古）草原退化梯度的四个植物群落中从不同地下芽类型中招募的营养后代进行了调查。这个梯度在 1000 米到 1500 米之间，是由于过度放牧造成的。为羊草草原，面积约3.0×105公顷。在确定整个草地退化梯度上的营养后代总密度时，分蘖芽的补充占主导地位（>80%）。然而，在草地退化早期阶段，分蘖分株对总分株补充的贡献比例显着大于退化后期（P <0.05），而根茎分株则表现出相反的模式。草地退化后期，根源分株对分株总密度的贡献率和密度显着增加（P <0.05），而球根分株的贡献率和密度在整个草地退化梯度上保持相对恒定。半隐植物[即西伯利亚芨芨草、隐子草、羊茅、鸡冠草、早熟禾、大针茅]对植物总物种丰富度的相对贡献下降，而地球植物[即冰草、苔草]对植物总物种丰富度的相对贡献下降。羊草、韭菜、二齿草、细草、黄芪、白花草、细叶鸢尾、委陵菜、二叉子草、白头翁、锯齿草、唐松草]随草地退化程度的增加而增加。我们的结果表明，随着草地退化的加剧，分株、根茎和根衍生的分株相对于分株总密度的比例的变化反过来决定了研究植物群落中半隐生植物和地球植物比例的变化。
ABSTRACT Since the contribution of total belowground bud bank and different bud types to community regeneration has rarely been explored, the vegetative offspring recruited from different belowground bud types was investigated in four plant communities along a grassland degradation gradient in northeastern China (Inner Mongolia). This gradient, between 1000 and 1500 m a.s.l., has been caused by overgrazing. It is a Leymus chinensis steppe which occupies about 3.0×105 ha. Recruitment from tiller buds was dominant (>80%) in determining the total vegetative offspring density along the whole grassland degradation gradient. However, the proportional contribution of tiller-ramets to total ramet recruitment was significantly greater (P <0.05) during earlier than later stages of grassland degradation, while that of rhizome-ramets showed an opposite pattern. While the percentage contribution and density of root-derived ramets to total ramet density increased significantly (P <0.05) during the late stages of grassland degradation, those of bulb-ramets kept relatively constant along the whole grassland degradation gradient. The relative contribution of hemicryptophytes [i.e., Achnatherum sibiricum, Cleistogenes squarrosa, Festuca ovina, Koeoleria cristata, Poa annua, Stipa grandis] to total plant species richness decreased, while that of geophytes [i.e., Agropyron cristatum, Carex korshinskyi. Leymus chinensis, Allium anisopodium, A. bidentatum, A. tenuissimum, Astragalus galactites, Cymbaria dahurica, Iris tenuifolin, Potentilla acaulis, P. bifurca, Pulsatilla turczaninovii, Serratula chinensis, Thalictrum aquilegifolium] increased with the increases of grassland degradation. Our results showed that as grassland degradation increased, changes in the proportion of tiller-, rhizome- and root-derived ramets with respect to total ramet density determined in turn changes in the proportion of hemicryptophytes and geophytes in the study plant communities.