万年县耕地景观破碎度变化及原因分析

Analysis of Changes and Causes of Farmland Landscape Fragmentation in Wannian County

基于Arcgis和Mapgis软件,利用万年县1992、2007和2013年土地利用数据资料,运用土地评价法和景观格局指数分析的方法,选取一些土地评价指标和景观格局指数,对万年县耕地景观格局进行分析。研究表明：万年县耕地多呈带状和团状分布,1992～2013年这21年以来耕地重心向西北方向偏移;斑块平均面积不断降低,斑块密度和景观形状指数不断上升,说明景观破碎度不断增加,斑块形状不断复杂;耕地景观优势度上升,多样性和均匀度下降。万年县耕地格局在2007～2013年期间变化幅度比1992～2007年期间大,说明万年县变化趋势在加快。

According to the land use data of Wannian county in the years 1992,2007 and 2013,based on the software Arcgis and Mapgis,we selected several land evaluation indexes and landscape pattern indexes to analyze the landscape pattern of cultivated land in Wannian county by using the methods of land evaluation and landscape pattern index analysis. The research results indicated that： the farmland of Wannian county was distributed mostly in the shape of strip and group,and the gravity center of the cultivated land had shifted to the northwest in the past 21 years（ 1992～2013）; since 1992,the average patch area was decreasing,while the patch density and landscape shape index was increasing,suggesting that the landscape fragmentation degree was increasing and the shape of patches constantly became complex; in these 21 years,the landscape dominance of cultivated land increased,while the diversity and evenness decreased; the rangeability of cultivated land pattern in Wannian county from2007 to 2013 was greater than that from 1992 to 2007,which showed that the variation trend of cultivated land pattern in this county was accelerated.