耕地整理的景观效应分析

论文通过对不同耕地类型区的典型样区调查获得的小尺度耕地景观现状特征与各耕地类型在不同整理水平下的耕地景观细部规划设计下的景观特征进行对比分析来研究北京市延庆县耕地整理的景观效应。选用斑块平均面积、平均周长、密度、边界密度、平均斑块周长面积比等指标来描述整理前后耕地景观斑块特征的变化;采用廊道类型、廊道占耕地景观面积的比例、各类型廊道占总廊道长度的比例、密度、网络连通度、网络环通度等来表达整理前后廊道特征的变化。研究结果表明,通过耕地整理明显提高了斑块平均面积、平均周长,降低了斑块密度、边界密度、平均斑块周长面积比,提高了景观粒度,减小了耕地景观破碎化程度和耕地景观被边界分割程度。整理后廊道占耕地景观面积比例减小;整理后耕地廊道系统中各廊道类型占总廊道长度的比例趋于合理;廊道类型中增加了农田防护林带,改变了耕地内单一类型景观格局;提高了道路、沟渠等廊道的网络连通度和环通度,有利于农田生态系统中物质和能量流动。

Study on Landscape Effects from Cultivated Land Consolidation

This article analyzes the landscape effect resulting from cultivated land consolidation in Yanqing county by contrasting landscape characteristics of different types of cultivated land between those obtained from the survey in the representative areas and those under detailed designing and planning for landscapes at different consolidation levels.The indices are introdu-ced to measure the changes of patch characteristics before and after consolidation,such as mean area of a patch,mean perimeter of a patch,patch density,perimeter density and the ratio of mean perimeter of a patch to its area.The differences of corridor characteristics before and after consolidation are illustrated by the indices of types of corridor landscapes,the proportion of area of all the corridors to the area of cultivated land,density of different corridors,networks connectivity,networks ring,etc.The results indicate that the mean area and mean perimeter of a patch obviously increase and the patch density,perimeter density and the ratio of the mean patch perimeter area decrease after consolidation.This implicates that cultivated land consolidation increases landscape granularity and decreases the degree of fragmentation and boundary division of landscapes.The proportion of the area of all the corridors to the area of cultivated land falls after consolidation,which reduces the coefficient of non-effective cultivated land.The proportions of the length of every corridor to that of all the corridors are rationalized.Farmland shelterbelt enriches corridor types in cultivated land which can be taken as additional corridor types.The connectivity of corridors networks and ring roads or ring ditches is enhanced,which benefits the flow of energy and material.