县域尺度下景观指数的粒度效应

Granularity effect of landscape index at the county scale

【目的】尺度的合理确定是景观格局和生态研究过程的关键。研究县域尺度下景观指数的粒度效应,并计算景观指数的适宜粒度范围对分析景观格局变化具有重要意义。【方法】以2017年安徽省宿松县的景观分布图为数据源,从类型和景观水平分析了各个景观指数在20~500 m粒度范围内的粒度效应,并选取适宜的粒度范围;通过拟合函数揭示不同景观格局指数随粒度增大的变化特征;结合景观面积损失精度评价模型确定宿松县景观格局变化的最适宜空间粒度值。【结果】景观指数具有一定的空间粒度效应性,其中大部分景观指数的可预测性强,但景观总面积、平均面积分维数、平均形状指数、Simpson多样性、Simpson均匀度指数对空间粒度响应不敏感;景观指数的粒度效应曲线可分为单调递减、单调递增、无变化、复杂变化4种类型;景观指数的拐点主要集中在70和200 m;在景观水平下景观指数粒度效应曲线拟合后的函数主要为幂函数,且拟合程度高。【结论】宿松县景观格局变化的适宜粒度为100~110 m,最佳粒度为100 m。图3表1参27。

[Objective]Reasonable scale determination is the key to the research of landscape pattern and ecology and has become one of the research focuses in landscape ecology and geography.Hence,the present research is focused on the granularity effect of landscape index at the county scale and appropriate granularity range of landscape index which is of great significance to the analysis of landscape pattern changes.[Method]First,with the landscape distribution map of Susong County,Anhui Province in 2017 was used as the data,an analysis was conducted of the granularity effect of each landscape index in the granularity range of 20-500 m from the two levels of type and landscape with the appropriate granularity range selected.Then,the fitting function was used to reveal the variation features of different landscape pattern indexes with the increase of granularity.Lastly,the optimal spatial granularity value of landscape pattern changes in Susong County was determined by the results of the precision evaluation model of landscape area loss.[Result](1)The landscape indexes had a certain spatial granularity effect and most of them were highly predictable;(2)Landscape total area index,average area fractal dimension,average shape index,Simpson diversity index and Simpson evenness index demonstrated low response sensitivity to spatial granularity;(3)There were four different types of granularity effect curves of the landscape index:monotonically decreasing,monotonically increasing,no change,and complex change and their inflection points were mainly occurred at 70 and 200 m;(4)Power function was the main function upon the favorable fitting of the landscape index granularity effect curve.[Conclusion]The suitable grain size range landscape pattern change was 100-110 m in Susong County,Anhui Province,and the optimal grain size value was 100 m.[Ch,3 fig.1 tab.27 ref.]