小流域人类活动的时空分异的景观格局特征——以纸坊沟流域为例

The Landscape Pattern Attribution to Time-space Distribution Law of Human Activities in Catchment——Taking Zhifanggou Catchment as an Example

纸坊沟流域位于黄土高原典型的丘陵沟壑区,是黄土高原小流域综合治理的示范区。从上世纪30年代以来,纸坊沟流域经历了从急剧破坏到缓慢恢复、基本保持和快速恢复的四个阶段,其中每一个阶段的人类活动都有其鲜明的特色。为了量化人类活动的程度和人类活动对土壤侵蚀的影响,本文将纸坊沟流域的土地利用类型归并为两类:加剧侵蚀的斑块和减缓侵蚀的斑块,并根据流域的海拔高度,给流域内每个土地利用斑块分别赋予位置属性。然后根据人类活动与土壤侵蚀的关系提取了5个景观格局指标,分别计算各指标自上世纪30年代以来的变化情况,并划分变化阶段,分析各阶段的景观格局变化情况后,本文得出以下结论:1)人类活动变化最剧烈最频繁的区域在坡下(即流域内海拔高度介于1100—1150m之间的区域);2)流域破坏性开发体现在斑块破碎化,而流域治理体现在斑块连通度增加;3)在流域治理过程中,流域景观格局变化特征体现在:减缓侵蚀的斑块被合并,加剧侵蚀的斑块部分被合并,部分被转化为减缓侵蚀的斑块。

Zhifanggou catchment located in loess hilly region on the Loess plateau. From 1930＇s, the catchment went through sharp changes. On the basis of change extent of landscape pattern, the research took the change phase into four stages. They were sharp broken stage, restore slowly stage, maintain stage and restore quickly stage. The feature of human action was obvious in every stage. To quantify the effect of human action on soil erosion, the land use types were divided into two sorts： the patch which soil erosion was aggravated and the patch which soil erosion is declined. At the same time, each patch was given an attribution about station. According to the relationship between human action and soil erosion, five landscape pattern factors were selected. The conclusions were as follow： 1） The human action was frequent in lower slope （altitude is between 1100 and 1150） ; 2） Unreasonable human action caused patch fragmentation, but reasonable human action caused patch connection; 3） In the course of restoration, the characters of patch in the catchment were as follow： the patch in which decrease soil erosion was declined merge, but the patch in which soil erosion was aggregated merge partly, and was changed to the patch which decreased soil erosion partly.