桐乡市乡镇耕地整理对耕地景观格局的影响及其分析

以桐乡市4个乡镇为研究对象，结合航空遥感和地理信息技术，在ArcGIS 8.3和ERDAS 8.6软件的支持下，通过数字矢量化、外业实地调查、地物调绘和核查以及室内补测的程序建立耕地景观图层数据库。在此基础上，运用景观格局指数：景观破碎度、分离度、形状指数和斑块分形维数对耕地整理前后的景观格局特征及其动态变化进行研究和分析。根据计算结果：整理后4个乡镇耕地景观的形状指数和分形维数都呈下降趋势，并且后者趋近于1，表明耕地景观的斑块形状越趋简单并越有规律；景观分离度减小，景观破碎度升高，斑块密度增大，而平均斑块面积却减小，这说明在目前耕地整理的初级阶段，不适当的耕地整理方式和方法使得耕地景观的分割、破碎程度加剧，孤立的嵌块体数量增加，将会影响农田生态系统的稳定性。因此，在开展耕地整理时，必须遵循可持续发展的基本原理，必须注重景观生态环境的保护，使之趋向生态环境保育型土地整理方向发展。

Impact of farmland consolidation on farmland landscape: a case study in Tongxiang county

Based on the technology of GIS and RS, with the help of software: ArcGIS 8.3 and REDAS 8.6, the basic theory and method for landscape ecology were applied to analysis of the dynamic changes in landscape pattern in Tongxiang county. The results showed that farmland landscape was influenced significantly by farmland consolidation. After consolidation, the landscape fragment index and density increased evidently, but patch average area declined concurrently; Of four towns, the landscape isolation index tended to decrease except Congfu town; The shape index and average fractal dimension declined obviously which indicated that consolidation made the farmland shape more simple and regular. All of these negative effects will result in instability of field ecological system. So, in the practice of farmland consolidation, the principle of sustainable development must be kept in mind and more attention should be paid to protection of landscape ecological environment.