典型小流域土地利用景观生态评价方法及其应用研究——以浙江仙居县永安溪为例

Methods and Applications of Landscape Ecological Evaluationin the Typical Small Watershed's Land Use

通过对浙江省东部仙居县永安溪流域选取位于上、中、下游地段的 3个乡镇 ,分别进行景观生态评价研究 ,主要是对各类斑块的面积、分维数、伸长指数、最小距离指数等计算 ,发现从上游到下游的土地利用方式发生了较大变化 ,如耕地所占比例有所增加 ,而乔木林地所占比例则相应降低。此外 ,人工干扰形成的耕地、居民点的平均斑块面积从上游到下游逐渐增加 ,表明居民的聚居程度逐渐增强。土地垦殖和耕作水平也发生了变化。在 3个乡镇中 ,人工景观如耕地、园地、居民点的最小距离指数均小于人工干扰较少的景观 (乔木林地、未利用地等 )。在 3个乡镇中分别选取居民点面积最大的 3个斑块 ,并以这 3个斑块为中心 ,分别建立了距离为 1 0 0 0m和 2 0 0 0m的缓冲区 (缓冲区A和B) ,均发现在中游地段的破碎度最大 ,下游次之 ,上游最小。除缓冲区A外 ,在缓冲区B和乡镇范围内 ,随着人为干扰的增强 ,多样性指数增大 。

The area,fractal dimension,elongation index and minimum distance index of patches in three villages and towns,which are located at up,middle and down Yonganxi River basin,Xianju county,Zhejiang province,were calculated with landscape ecological evaluation.The result shows that the land use types change a lot from upriver to downriver.Otherwise the mean patch areas of man made landscape types such as farmland and residential site become larger from upriver to downriver.It indicated that ,land cultivating and farming levels are quite different in different regions.In the three villages and towns,the minimum distance index of man made landscape is less than that of forest and waste land;buffer zones with 1 000m distance and 2 000m distance (buffer A and buffer B ) are created in the three villages and towns,the buffer centers are three residential sites which are the largest residential site in their villages and towns.It indicated that the fragmentation is the biggest in the middle river and smallest in the upriver.In buffer B and villages and towns region,with an exception of buffer A ,the diversity index increases with increased human disturbance,while dominance decreases.