基于最佳分析尺度的广州市景观格局分析

Landscape Pattern Analysis of Guangzhou Based on Optimization-Scale

利用遥感、GIS技术和指数分析软件确定最佳分析尺度,对广州市景观格局进行量化研究。对14个不同粒度的栅格图分别进行35个相关指数运算,根据15个敏感指数确定最佳分析尺度为120 m;选取空间组成和空间构型两方面的系列指数,在此尺度下对研究区域进行指数运算和格局分析。研究结果表明:广州是以林地、水田和旱地为主要景观类型的复合景观结构,优势景观明显,3种主体景观类型集中连片、分布广泛;建设用地比例比全国平均水平偏高;建设用地和水库坑塘斑块密度大,平均斑块面积小,景观破碎度较高。景观格局的量化受尺度效应影响,表现出空间异质性的尺度依赖性,因此在格局分析时需选择最佳分析尺度,突出格局的尺度性。

Pattern analysis is an important focus of landscape ecology. Spatial pattern heterogeneity exhibits various patterns at different scales, therefore different observed scales affect the results of spatial analysis. Effects of changing scale on spatial analysis have been studied for decades in geography and ecology, but few previous studies expounded the quantitative approach about the optmization-scale. Some studies describe the landscape pattern neglecting the scale effects, which may lead to the difference deviation. The main goal of this study was to set the optimization-scale and study the pattern under this scale. In this paper, the landscape patterns about Guangzbou are researched by remote sensing （RS）, geographical information system （GIS） and the landscape analysis program FRAGSTSTS. The TM image of Guangzhou on January 2,2000 was used as the basic data. After geometry calibration, the landuse classification was set with 10 types. Because the basic cell size （the original pixel） of the TM is 30 m, a series of landuse raster graphs were charted in 14 different multiple grain sizes of 30 m, 60 m, 90 m, etc. In order to get the optirnization-scale,35 indices were calculated in 14 analysis scales. Some indices＂ scale effect curves have no inflexion,some have no rule and at last 120 m is defined as the optimization-scale by 15 sensitive indices. Based on the optimization -scale,indices about composing and structure in both landscape level and class level were chosen to describe the pattern of Guangzhou. The analysis about landscape patterns reveals that the compound landscape patterns composed of multiple landscape types, and paddy forest and dry land are the dominant types of landscape. Urban land is at the higher level than average of China. The landscape fragmentation is high. The diversity of urban land and reservoir is the largest in all the land types.