龙门山地区水土流失敏感性评价及其空间分异

Sensitivity Assessment and Spatial Distribution of Soil Erosion in Longmen Mountains Region

[目的]确定水土流失优先保护区和需要生态修复的区域,为龙门山的生态环境治理和社会经济发展提供重要的决策依据。[方法]主要考虑降水、土壤侵蚀和地形起伏和植被覆盖等通用土壤流失方程中的水土流失影响因子,对龙门山地区水土流失敏感性进行辨识,并借助于3S技术强大的空间数据采集和分析功能,计算水土流失敏感性综合得分值,按照ArcGIS自然断点分类方法将水土流失敏感性分为不敏感区、较敏感区、低度敏感区、中度敏感区和极敏感区5个等级。[结果]龙门山东部山前丘陵地区,人类活动频繁,水土流失敏感性最强,占总面积的34.12%;中部中海拔山地区域,水土流失敏感性次之,占总面积的28.30%;西部山区,水土流失敏感性最低,所占面积比重较小,为13.65%。[结论]龙门山地区水土流失敏感性具有明显的地域分异特点,人类活动频繁,对自然生态系统的干扰强烈,水土流失敏感性最强,人类活动是加剧龙门山地区水土流失敏感性的主要因素。

[Objective] The regional priority with regard to soil and water loss and ecological restoration was explored to provide some major decision-making bases for ecological environment management and social and economic development in Longmen Mountains area.[Methods] Based on the powerful spatial analysis function of GIS, the spatial values of soil erosive sensitivity in Longmen Mountains area were identified and calculated in consideration of all comprehensive influence factors of soil and water loss, as precipitation, soil erosion, topography relief and vegetation cover, etc. According to the classification method of natural breakpoint of ArcGIS, areas in term of sensitivity degree of soil erosion were designated as following：insensitive area, sensitive area, low sensitive area, moderate sensitive area and extreme sensitive area.[Results] The highest sensitivity areas were mainly distributed in the eastern piedmont hills and alluvial plains, accounting for 34.12% of the total area. Moderate sensitivity areas were mainly distributed in the central hilly areas, accounting for 28.30% of the total area. Low sensitivity zone were mainly distributed in the western mountains, accounting for 13.65% of the total area. The covered areas by different sensitivity degree were largely overlapped spatial distribution of human activity frequency.[Conclusion] The sensitivity of soil and water loss in the study area had obvious regional differentiation with regard to the erosive sensitivity. It is the frequent human activity that cause strong disturbance to natural ecosystem and cause subsequent strong sensitivity to soil erosion.