Rain-Shadow in the High Andes of Ecuador Evidenced by Páramo Vegetation
Rain-Shadow in the High Andes of Ecuador Evidenced by Páramo Vegetation
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帕拉莫植被证明了厄瓜多尔安第斯山脉高地的雨影
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
Simon Lægaard
中科院分区：
文献类型：
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作者：
P. Sklenář;Simon Lægaard
热带高山的湿度梯度反映在风向和背风面植被带的移动以及物种组成和植被结构的变化上。在厄瓜多尔的钦博拉索和安蒂萨纳两座山脉的两侧(西部和东部)研究了Superpáramo植物区系和植被。以半随机方式排列的植被样本研究了地带性植被，这些数据得到了出现在地带性生境中的物种的补充。用排序和聚类技术对植被样本进行分析，同时用两种不同的区系相似性指标(定量区系相似性指数和两个山间共有物种的观测值和期望值的比较)来评价研究地点之间的区系关系。就海拔而言，Superpáramo带不对称地出现在两座山脉上，通常在东侧较低。山与山之间具有对应坡向的坡度比每座山的相对坡度更相似。观察到的植物区系格局是在降水梯度的背景下解释的，这导致了山脉西侧的雨影。讨论了钦博拉索西侧沙漠状区域的出现，即所谓的Arenal Grande，以及独特的Páramo植被。
Abstract Gradients of humidity on tropical high mountains are reflected by shifts of vegetation belts and changes in species composition and vegetation structure on the wind- and leeward sides. The superpáramo flora and vegetation were studied on opposite sides (west and east) of two Ecuadorian mountains, Chimborazo and Antisana. Zonal vegetation was studied in vegetation samples set out in a semirandom way, and the data were complemented by species occurring in azonal habitats. Ordination and clustering techniques were used to analyze the vegetation samples, while two different measures of the floristic similarity (index of quantitative floristic similarity and comparison of the observed and expected numbers of species shared between the mountain pairs) were employed to evaluate the floristic relationships between the study sites. The superpáramo belt occurs asymmetrically, with regard to altitude, on the two mountains, being generally lower on the eastern side. Slopes with corresponding aspects between the mountains were more similar than were the opposite slopes of each mountain. The observed floristic pattern is interpreted in the context of the precipitation gradient leading to a rain-shadow on the western side of the mountains. The occurrence of the desert-like area, the so-called Arenal Grande, and the unique páramo vegetation on the western side of Chimborazo is discussed.