Deforestation Impact on Water Dynamics in a Venezuelan Andean Cloud Forest
Deforestation Impact on Water Dynamics in a Venezuelan Andean Cloud Forest
复制标题
毁林对委内瑞拉安第斯云林水动态的影响
DOI：
10.1579/0044-7447-29.7.440
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发表时间：
2000
影响因子：
2.4
通讯作者：
F. Rada
中科院分区：
文献类型：
--
作者：
M. Ataroff;F. Rada
摘要 安第斯云雾林在流域水文和防止侵蚀方面发挥着重要作用。尽管大多数云雾森林属于官方保护区，但大量云雾森林正在被砍伐并被放牧的牧场所取代，这是委内瑞拉云雾森林环境中最重要的土地利用。人们对天然林的水动态以及牧场替代的影响知之甚少。自 1996 年以来，我们一直在开展一个研究项目，旨在研究森林的一些水通量并评估牧场替代对水文的影响。研究地点位于委内瑞拉安第斯山脉梅里达州La Mucuy（海拔2300米，降雨量3124毫米）。结果表明，在森林中，91%的总进水来自降雨，9%来自云水。总树叶截获率为 51%，这对于热带山地森林来说是一个很高的值。大约 49% 的总流入水通过径流到达地面，而枯枝落叶截留了 6% 的水，最后 1.4% 通过地表径流流失。因此，渗透率必须在42%左右。大约 16% 通过蒸腾作用损失，剩下大约 26% 用于排水。牧场研究结果显示，截留率为 7%，而地表径流 (2%) 和蒸腾量 (约 66%) 均高于森林。我们关于土壤水分状况的第一个结果表明，森林土壤（上层）的水分百分比明显高于牧场土壤。
Abstract Andean cloud forests play an important role in watershed hydrology and protection against erosion. Even though most cloud forests fall under officially protected areas, a good deal of the cloud forests are being deforested and replaced by pastures for grazing cattle, which is the most important land use in Venezuelan cloud forest environments. The water dynamics of the natural forest as well as the impact of replacement by pastures are poorly understood. We have been conducting a research project since 1996, in order to study some of the water fluxes of the forest and to evaluate the hydrological impact of replacement by pasture. The study site is located at La Mucuy (2300 m with 3124 mm rainfall), Merida State, in the Venezuelan Andes. The results show that, in the forest, 91% of total incoming water was from rainfall and 9% was from cloudwater. Total foliage interception was 51%, which is a high value for a tropical montane forest. About 49% of the total incoming water reaches the ground as throughfall, whereas litter intercepts 6% of the water and a final 1.4% was lost by surface runoff. Therefore, infiltration must be about 42%. Approximately 16% was lost by transpiration leaving about 26% for drainage. Results from pastureland studies show 7% interception, while surface runoff (2%) and transpiration (about 66%) were higher than in the forest. Our first results on soil water status suggest that the forest soil (upper horizon) has a significantly higher % moisture than the pasture soil.