黄土丘陵小流域景观空间格局动态分析——以固原市上黄试区为例

 为黄土高原土地资源合理利用及区域可持续发展提供参考,以上黄试区为例,在地理信息系统支持下获得计算景观多样性的有关参数,选取斑块大小及数量、分维数、斑块伸长指数、多样性、优势度、均匀度和破碎度等指标,对黄土丘陵小流域10年来景观多样性动态变化进行分析。结果显示:1995—2004年,该试区总斑块数增加了6个,斑块变化明显的主要表现为:坡耕地及天然草地斑块分别减少19个和12个,人工草地斑块及梯田分别增加15个和9个;平均斑块面积及平均斑块周长分别下降了0.14hm2和185.36m2;梯田、天然草地、疏林地、园地及居民点用地分维数,都有不同程度的下降,而坡耕地、人工草地、灌木林地及未利用地景观的分维数有所上升,水浇地、川台地、乔木林地、水域景观分维数保持不变;上黄试区景观异质性特征表现为:均匀度指数下降5.86,景观破碎度指数上升0.002,人为干扰度增加1.95,景观类型多样性指数下降0.25,优势度指数上升0.25。目前,试区从耕地及草地为主的景观生态系统,转变为以林地和草地景观为主的高度异质化的景观生态系统,人类活动的干预,是驱动该试区景观空间格局变化的主要驱动因素。

Dynamic analysis on the spatial pattern of landscape of small watershed in loess hilly-gully region:A case study of Shanghuang test area in Guyuan

In order to provide reference for reasonable use of land resource and regional sustainable development in loess plateau, taking Shanghuang test area as the study area, some landscape diversity indexes were attained under the support of GIS technology. Utilizing the indexes such as patch size and amount, average fractal dimension, patch extension index, diversity index, dominance, consistency degree and fragmentation, the dynamic changes of landscape diversity in the loess hilly-gully region during the past 10 years were analyzed. The results showed that the total number of patch increased by from 1995 to 2004, among which, slope farmland and crude grass land decrease by 19 and 12 respectively, the artificial grass land and terrace farmland increase by 15 and 9 respectively, the average area and perimeter of patches decrease by 0.14hm² and 185hm² separately, the patch fractal dimension of terrace, crude grass land, woodland, orchard and village decrease in different degrees, slope farmland, artificial grassland, shrub land and unutilized land increase slightly, the irrigable land, plain, arbor land and water area were kept up. The characteristics of landscape heterogeneity are depicted that the consistency degree and diversity index decrease by 5.86 and 0.25 respectively, while the fragmentation and dominance increase by 0.25 and 0.002 respectively. The degree of man-made interference increases by 1.95. The landscape ecosystem mainly composed of farmland and grass has already changed in to highly heterogeneous landscape ecosystem mainly composed of forest and gross. Human activity is the main driving factor for the dynamic changes of spatial pattern of landscape in this test area.