基于不同分辨率影像的山区耕地细碎化评价及其尺度效应

Cultivated land fragmentation in mountainous areas based on different resolution images and its scale effects

研究耕地细碎化的尺度效应对山区耕地细碎化遥感监测、耕地整治与可持续利用具有重要意义。选取贵州省坝区孙家村、丘陵区亚鱼村和山地区小坝村3个不同地貌背景的典型村为案例区,在构建细碎化测度模型基础上,量化分析0.1 m、1 m、2 m、5 m、10 m分辨率下耕地细碎化程度的尺度效应。研究结论:①随着影像分辨率下降,不同地貌背景下的耕作地块特征有明显的尺度效应。②不同地貌背景下的耕地细碎化程度存在差异,丘陵区的细碎化程度最高,坝区次之,山地区最低。不同影像分辨率下的耕地细碎化程度具有明显的尺度效应,3个典型村的耕地细碎化指数均呈现幂函数式下降;且不同地貌背景的耕地细碎化程度对尺度变化响应程度不同,坝区的耕地细碎化粒度响应最为强烈,丘陵区次之,山地区最弱。③以前1个尺度为参照计算耕地细碎化程度的损失精度时,坝区和丘陵区的耕地细碎化程度在影像分辨率由2 m变为5 m时最敏感,山地区小坝村对尺度变化的敏感度从2 m处呈现升高趋势;以基础尺度为参照时,丘陵区的耕地细碎化程度对尺度变化的敏感度最高,山地区次之,坝区最低。研究旨在为山区的耕地细碎化调查、评价以及治理提供借鉴。

Studying the scale effect of cultivated land fragmentation is of great significance for remote sensing monitoring, remediation and sustainable use of cultivated land in mountainous areas. This paper selects three types of typical landforms with different geomorphological backgrounds as the case area, namely, Sunjia village in the dam area, Yayu village in the hilly area and Xiaoba village in the mountain area. The fragmentation measurement model is constructed to quantitatively analyze the scale effect of the degree of cultivated land fragmentation at the five resolutions of 0.1 m, 1 m, 2 m, 5 m and 10 m in Guizhou mountainous areas. The main conclusions are as follows:(1) with the decrease of image resolution, the characteristics of cultivated plots under different landscapes have obvious scale effects.(2)There are differences in the degree of cultivated land fragmentation under different geomorphological backgrounds. The fineness of the hilly area is the highest, followed by the dam area, and the mountain area is the lowest. The degree of cultivated land fragmentation at different image resolutions has obvious scale effect, and the index of cultivated farmland fragmentation in all the three typical villages show a power function decline. In addition, the degree of cultivated farmland fragmentation with different geomorphological backgrounds is different in response to scale changes. The grain size response of cultivated land in the dam area is the strongest, followed by the hilly area and that of the mountain area is the weakest.(3)With the previous scale as a reference to calculate the loss accuracy, the degree of cultivated land fragmentation in the dam and hilly areas is the most sensitive when the image resolution is changed from 2 m to 5 m, while the sensitivity of the mountain area to the scale change is increasing. When the basic scale is used as the reference, the degree of cultivated land fragmentation in the hilly area is the most sensitive to the scale change, followed by the mountain area, and the lowest is in the dam area. The study aims to provide reference for the investigation, evaluation and treatment of cultivated land fragmentation in mountainous areas.