宁夏固原市森林水源涵养功能时空动态研究

Study on Dynamic Spatial and Temporal Change of Water Conservation Function of Forest Ecosystem in Guyuan of Ningxia

宁夏固原市属于中国＂两屏三带＂中的＂黄土高原—川滇生态屏障＂,是泾河的发源地也是黄土高原的重要的水源地,其境内的六盘山国家级生态保护区具有重要的生态价值.开展固原市森林水源涵养功能研究将有助于揭示森林生态系统结构时空动态对水源涵养功能的影响,并为当地林业发展、生态文明建设以及政府绩效考核提供重要参考和依据.在分析了2000~2010年固原市林地结构动态的基础上,使用综合蓄水能力法,计算了森林水源涵养量及其价值并分析时空分异的影响因素.结果表明：2000~2010年,固原市林地面积增长15.94%.由于灌木林单位面积水源涵养量和面积比例最大,导致灌木林对固原市森林水源涵养功能的贡献最大（80%以上）.森林不同层次对水源涵养量的贡献为：土壤蓄水量〉林冠层截留降水量〉枯落物层持水量.固原市新增林地面积以灌木林为主,对水源涵养量增长的贡献占93.34%.随着坡度增加,森林涵养水源量先上升,在15°~25°坡地达到最大值,随后下降.由于造林活动主要集中在5°~25°坡地,近10年的涵养水源量在该坡度增长最明显.2000~2010年,固原市水源涵养价值上升23.25%,主要体现在对水量和水质的调节方面的价值增长.退耕还林还草工程是林地面积、水源涵养量及其价值时空间动态的主要原因.

Guyuan City belonging to ＂the Loess Plateau-Sichuan Yunnan Ecology barrier＂of ＂Two Barriers Three Belts＂in China,is the origin of Jinghe River as well as the important water source region on the Loess Plateau,within which Liupan Mountain,one national ecological reserve,plays a significant ecological role. The study on the water conservation function of forest in Guyuan will be helpful to understand the impact brought by the dynamic structure change of forest on this ecological function,and contribute as an important reference for the local forestry development as well as the ecology civilization construction. Based on the study on the dynamic change in the forest structure,this paper evaluated and analyzed the spatial and temporal change of the water conservation capacity of forest ecosystem during 2000 ~2010 in Guyuan. The result indicated that,during 2000 ~ 2010,the area of forest in Guyuan expanded15.94%. As the unit area water conservation capacity and the area proportion of the scrubby forest were the largest,the scrubby forest made the largest contribution（above 80%） to the water conservation. The contribution of forest on different slope levels to the water conservation was： The soil water storage canopy precipitation interception litter layer water-holding capacity. The scrubby forest primarily took the largest proportion of the additional forest area,which accounted for 93.34% of the additional water conservation quantity. When the slope became steeper,the quantity of forest water conservation rose and reached the top at slope 15 ~ 25°,afterwards,dropped down. But because the afforestation activity mainly concentrated on slope 6° ~ 25°,the quantity of water conservation has grew obviously in this level of slope in the past ten year. From 2000 to 2010,the value of water conservation function of forest value rose23. 25% in Guyuan,mainly reflected in the regulation value of water quantity and water quality. The Slope Land Conservation Project is the main causes of dynamic forest area,the quantity and economic value of water conservation.