河谷型城市城乡结合部景观格局空间尺度效应分析——以兰州市西固区土地利用格局为例

以兰州市西固区土地利用格局为例,利用2005年SPOT5遥感影像和正射航空影像数据,选取14个常用的景观指数,从景观水平和类型水平2个方面分析景观指数随尺度变化的基本规律,采用200m×200m正方形将研究区土地利用数据切分成规则格网,计算每个格网的多样性指数,通过半方差分析研究西固区多样性空间结构特征。结果表明:10m是西固区土地利用景观的本征观测尺度;研究区景观类型和景观格局特征随尺度增大变化显著,体现出一定的尺度依赖性;各乡(镇、街道)的景观指数呈现出城市中心—城乡交错带—乡村的分异特征,梯度变化明显;西固区多样性空间分布属于中等强度空间相关,高值区主要分布于黄河沿岸。

Analysis of Spatial Scale Effect on Landscape Patterns in Peri-Urban of Valley-Shaped Cities-A Case Study of Land Use of Xigu District of Lanzhou

The land use pattern of Xigu District, Lanzhou was selected as a study area for analysis of variation of landscape index with grain size from the landscape level and type level, using 14 commonly used landscape indices and 2005 SPOT 5 remote-sensing images and orthographic aerial images. The study area delineated digitally into regular grids, 200 m ×200 m, of which SHDI was worked out one by one, and spatial structure characteristics of the diversity of Xigu Distriet were determined and analyzed with the semi-variogram method. Results demonstrate that 10 m was an intrinsic observation scale for land use landscape of Xigu District. The characteristics of landscape types and landscape patterns of the study area varied significantly with the increase in grain size, reflecting certain scale dependence. Landscape indexes of the townships (towns and neighborhoods) displayed differentiation characteristics of urban-peri-urban-countryside and apparent gradient variation. Spatial distribution of the diversity of Xigu District is a kind of spatial correlation of moderate strength. Areas of high values are distributed mostly alongside the Yellow River.