绿洲景观中居民地空间分布特征及其影响因子分析

Spatial pattern in residential area and influencing factors in oasis landscape

以张掖绿洲居民地为研究对象 ,用景观格局分析软件 FRAGSTATS计算了 5个景观格局指标 ,用GIS计算了形状指数、景观类型空间邻接比例、最邻近指数、最近距离以及居民地的耕作半径 ,借鉴聚落地理学中的居民地分布研究方法 ,分析了居民地的空间格局特征及其影响因子。结果表明 :1耕地是张掖绿洲内的景观基质 ,居民地是绿洲内分布最广、斑块数最多的景观类型 ;居民地的平均斑块面积小、形状简单、聚集度高 ,与耕地的空间邻接长度和数目均最高 ,其空间分布类型存在空间差异 ;2耕地是影响居民地分布格局的重要因子。缓冲区分析方法可以从理论上确定居民地的耕作半径 ,耕作半径与居民地的空间分布类型紧密相关 ;3居民地到渠系的平均最临近距离为 2 1 5m,75.6%的居民地中有渠系穿过 ;4居民地分布受中心城市——张掖市的影响程度极其明显 ,两者呈指数相关 ;5景观格局分析、居民地分布研究方法和 GIS空间分析方法的有效结合 ,可以较好的反映居民地的空间分布特征及其影响因子的相关性 ;6借鉴聚落地理学的最近邻点指数具有明确的生态含义 。

In this paper, we studied the spatial patterns in the residential area and its i nfluencing factors in Zhangye oasis located in the middle reaches of Heihe River basin in northwest China. Five pattern indices (including the Area, the Mean Pa tch Area, the Patch Density,Average Nearest Distance and the Aggregation Index) were computed and analyzed using FRAGSTATS version 3\^0, and the shape index an d the spatial neighboring length and number between the residential area and oth er patches were calculated using Geographic Information System, and the Nearest Index that determines the type of residential area distribution were counted usi ng the method of settlement geography, and the radius of cultivation were comput ed using the method of buffer zone. The results indicated that the irrigated far mland which is the matrix of oasis landscape possesses the largest area in Zhang ye and its sub-oasis, and the residential patches are most broadly distributed and dominate the landscape patches. The mean area of residential area is small, and the shape is simple but its aggregation index is high. The irrigated farmlan d is the type that has the highest neighboring length with residential area, sug gesting a complex and close relationship between them. The distribution of resid ential area is random in Shajing sub-oasis but aggregated in the scale of oasis and other two sub-oasis (including the core oasis and Ganjun sub-oasis). Farm land is the key factor influencing the pattern of residential area distribution. The radius of cultivation, that can be derived by the method of buffer zone the oretically, showed a high correlation with the type of residential area distribu tion, suggesting that the former has a link of the latter. The average distance between residential patches and the nearest canals and rivers is 215m, and more than 75\^6% villages have canals passing through. The administrative center, Zha ngye city, has significant impacts on the distribution of residential area, the nearer the distance from Zhangye city, the greater the impacts on the residentia l area. We concluded that the combination of landscape pattern analysis, the set tlement geography and GIS can benefit the research on the pattern of residential area distribution and its influencing factors, and the Nearest Index, that have explicit ecological meanings, can be used to replace the Aggregation Index in F RAGSTATS.