基于地形梯度特征的福州市景观格局演变

地形是土地景观格局变化的重要因素.为揭示不同地形梯度下景观格局的时空特征和变化规律,以1995、2005和2015年3期福州市遥感影像和数字高程模型(DEM)数据为基础,运用地形位指数、土地利用分布指数、地学信息图谱分析和景观指数等方法,探讨景观格局的地形梯度效应以及形成原因.结果表明: 研究期间,研究区林地主要位于中低、中高和高等级地形位,农地、水体、建设用地和未利用土地主要集中位于低等级地形位.1995—2015年,福州市林地、农地和未利用土地面积减少,建设用地和水体面积增加.景观类型变化以稳定型为主,主要分布于中低、中高及高等级地形梯度区域;景观格局在地形梯度上变化差异明显,低地形位区域景观类型主要转向建设用地,而在中低及中高地形位区域,主要发生农地与林地的交替转变.研究区景观格局破碎化、景观异质性和景观多样性等属性逐年上升,随着地形梯度升高而降低.

Landscape pattern evolution along terrain gradient in Fuzhou City,Fujian Province,China

Terrain is an important factor in land landscape pattern change. To reveal the spatial and temporal characteristics and variation of landscape pattern along a terrain gradient, we used three remote sensing images and digital elevation model (DEM) data of Fuzhou in 1995, 2005 and 2015 to investigate the topographic gradient effect of landscape pattern and the cause of formation based on terrain index, land use distribution index, geo-informatics map analysis and landscape index. The results showed that forestland was mainly distributed in middle-low, middle-high and higher level terrain, while farmland, water body, construction land and unused lands were mainly distributed in the low rank terrain. From 1995 to 2015, the area of forestland, farmland, and unused land in Fuzhou decreased, while that of construction land and water body increased. The change of landscape type was stable, which was mainly distributed in middle-low, middle-high, and high grade terrain gradient region. In addition, landscape pattern changes were obvious across the terrain gra-dient. The landscape type of low terrain area mainly shifted to the construction land, but farmland and forestland had an alternation change in the middle-low and middle-high terrain area. The characteristics of landscape pattern fragmentation, landscape heterogeneity and landscape diversity in the study area had been increasing year by year, but they had decreased with the elevation of terrain.