Effect of flooding regime and understorey bamboos on the physiognomy and tree species composition of a tropical semideciduous forest in Southeastern Brazil
Effect of flooding regime and understorey bamboos on the physiognomy and tree species composition of a tropical semideciduous forest in Southeastern Brazil
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洪水状况和林下竹子对巴西东南部热带半落叶林地貌和树种组成的影响
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
D. A. Carvalho
中科院分区：
文献类型：
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作者：
A. Oliveira;E. A. Vilela;M. L. Gavilanes;D. A. Carvalho
在巴西东南部马德雷·德·德·米纳斯（Madre de Deus de Minas）的大沼泽（里约热内卢Grande）边缘的热带半落叶森林地区，分析了河流洪水状况、地形、土壤性质和树木和竹子种类分布之间的相互关系。在一个单一的森林地块（1.597公顷，71个相邻的225平方米样方）中进行了调查，该地块位于河湾内侧，从点坝延伸到斜坡顶部。所有乔木（树干基部直径≥5 cm）和竹竿均进行登记。在两年的时间里，收集并分析了土壤样本的性质，并监测了河流的水位。在点坝中，森林主要以洪堡柳（Salix humboldtiana）和印加木（Inga affinis）两种树种为主，且分布在不同的区域。这些地区土壤性质的差异表明沉积动力学的差异。典型对应分析（CCA）表明，坡地的植物区系组成与3个地形区系及其对应的洪涝形势具有显著的相关性。下斜坡对应于向点坝森林的急剧过渡，承受部分和年度洪水，并显示出非常独特的植物群，包括许多需要光的物种。中坡只是偶尔被特殊的河流洪水到达，其特点是高密度的毛竹。相对较低的密度和树木的基部面积，特别是较小的树木，提供了证据，表明竹子可能通过限制它们的繁殖来干扰树木。Ridgetop完全位于最高洪水水位之上。竹林密度较低，林下树木丰富。
The interrelationship between river flooding regime, topography, soil properties and the distribution of tree and bamboo species was analysed in an area of tropical semideciduous forest on the margins of the Rio Grande, in Madre de Deus de Minas, Southeastern Brazil. A survey was carried out in a single forest plot (1.597 ha, 71 adjacent 225 m2 quadrats) located in the inner side of a river bend and extending from the point bar to the top of the slope. All trees (≥5 cm diameter at the base of the trunk) and bamboo culms were registered. Soil samples were collected and analysed for their properties and the river level was monitored during a two year period. In the point bar the forest was dominated by only two tree species, Salix humboldtiana and Inga affinis, that tended to occur in distinct areas. Differences in soil properties between these areas suggest variation in sedimentation dynamics. In the sloping part of the plot, a canonical correspondence analysis (CCA) indicated that the floristic composition was significantly correlated with three topographic sectors and their corresponding flood regimes. The Lower Slope corresponds to the sharp transition to the point bar forest, endures partial and annual floods and shows a very distinct flora that includes many light-demanding species. The Middle Slope is only occasionally reached by exceptional river floods and is characterised by a high density of the bamboo Merostachys neesii. The comparatively low density and basal area of trees, particularly for the smaller ones, provide evidence that the bamboos are problably interfering with the trees by restricting their recruitment. The Ridgetop lies entirely above the highest flooding level registered. The density of bamboos is lower and the understorey trees abundant.