西安市土地利用景观格局动态演变及驱动力分析

Landscape Pattern of Land Use Dynamic Development and Driving Force in Xi'an

为探究西安市土地利用及景观格局的时空演变规律,以1995年和2013年的TM5遥感影像图为数据源,借助ERDAS9.1、ArcGIS9.3工具对此进行空间分析,得到西安市1995-2013年的土地利用转移矩阵,通过FRAGSTAT4.1软件得到景观格局指数,分析研究区域各县区的景观格局特征,并运用主成分分析法探讨景观变化驱动力。结果表明,西安市土地利用类型主要以林地为主,占50%左右,主要分布于山地丘陵地区;耕地是西安市较为重要的景观类型;1995-2013年林地、城镇建设用地与园地面积增加,呈"涨势",耕地、水域与未利用地面积减少,呈"落势",趋势状态指数Pt为0.4,表明土地利用变化整体接近动态平衡,呈双向转换趋势;西安市景观多样性指数从1.238下降到1.213,均匀度指数从0.691下降到0.677,优势度指数从0.554上升到0.578,破碎化指数从0.086下降到0.074,表明景观异质性程度降低;其中,经济与人口因素是耕地向城镇建设用地、园地转化的主要驱动力,亦是水域、未利用地发生转化的主要影响因子,政策因素是林地发生变化的根本原因。

dBased on the remote sensing images of two periods （TM in 1995,2013）,the temporal and spatial variations of land use/cover and landscape patterns in Xi＇an were explored with the spatial analysis tools of ERDAS9.1 and ArcGIS 9.3. The land use transfer matrixes of the districts or counties within Xi＇an during 1995--2013 were obtained. The characteristics of landscape patterns were examined by adopting index analysis method, which could be achieved by FRAGSTAT4.1 tools. The results showed that the dominant type of the land use in Xi＇an was forest land,accounted for about 50% ,which was mainly distributed in mountainous areas. Cultivated land was also an important landscape type. The areas of woodland, urban construction land,garden land increased and presented a rising trend, while the areas of cultivated land, water and unused land decreased significantly,and presented a declining trend. The index of Pt for the whole period was 0.4,indicating that the overall change of land use was closed to the dynamic balance by two-way transition. With the rapid development of social economy,the landscape diversity index decreased from 1. 238 to 1. 213,landscape evenness index decreased from 0. 691 to 0. 677, and the dominance index increased from 0. 554 to 0. 578,the fragmentation index decreased from 0. 086 to 0. 074 ,which indicated that landscape heyerogeneity reduced in the study area. The driving forces of the transformation of cultivated land to construction land and green land were from economic and demographic factors, which were also the main factors that influenced the transformation of waters and unused land. Policy factor was the root cause of forest land change.