基于土壤动态蓄水的森林水源涵养能力计量及其空间差异

水源涵养是森林提供的重要生态服务之一,而森林土壤对降水的拦蓄和调节起着主要作用。采用土壤动态蓄水能力法,以太湖流域安吉县森林资源二类调查和雨量站逐日降水量数据为基础,评估了森林的水源涵养能力,并将土壤水源涵养能力参数和降水数据进行空间栅格处理和相应的栅格运算,从而揭示了水源涵养的空间差异。结果表明:安吉县森林生态系统年涵养水源能力为19.66×10⁸ t,单位面积森林年涵养水源能力为14 788 t/hm²;从空间分布上看,森林水源涵养量沿西苕溪由上游向下游呈减少的趋势;从不同森林类型来看,竹林的水源涵养贡献率最大,达52.26%。

Water Conservation of Forest Ecosystem and its Spatial Differences Based on Dynamics of Soil Water Storage in Anji County

Water conservation is one of the important ecosystem services and forest soil plays a dominating role in conserving and regulating rainfall.With the increasing demand for clean water,the water conservation of forest ecosystem arouses considerable concerns.Based on the data of Category Ⅱ inventory of the forest resources in Anji County(2007) and daily precipitation,the water conservation of the forest ecosystems was estimated,using dynamics of soil water storage method.We also generated the spatial grid data of soil water storage capacity and precipitation and made raster calculations to show the spatial difference of water conservation.The results showed that a volume of 19.66×108 t was conserved in the forest ecosystem,and the water conservation capacity per unit area reached 14788 t/hm2.The volume of water conservation had a downward trend from upstream to downstream of Xitiaoxi River basin.The bamboo forest was the main contributor to the water conservation in Anji forest ecosystem(52.26%),followed by the broadleaf forest and the coniferous forest.