长江中游地区多尺度耕地景观格局演变特征

Multi-scale Analysis of Farmland Landscape Dynamic Pattern in the Middle Reaches of the Yangtze River

揭示区域耕地景观格局多尺度演变特征有助于从区域层面全面解读耕地利用状况,可为区域耕地保护和生态环境建设提供重要参考。采用景观格局指数分析方法和数理统计手段,选取10个景观指数,从城市群、省域、流域3个不同空间尺度分析了长江中游1995~2014年耕地景观格局变化特征。结果表明:(1)1995~2014年间,长江中游耕地总面积以平均每年308.21 km^2的降速大量减少。其中,湖北、湖南、江西3省年均降速分别为185.12、70.26、52.76 km^2/a,武汉城市圈、长株潭城市群、环鄱阳湖城市群三大城市群年均降速分别为180.03、48.19、56.16 km^2/a。(2)不同省份耕地景观变化的方向和程度存在较大差异。湖南省耕地连通性先增后减,景观的破碎度先减后增,而湖北省和江西省耕地景观的连通性和破碎度变化趋势则与湖南省恰好相反,且变化强度明显弱于湖南省。(3)不同城市圈(群)耕地景观变化的方向和程度差异明显,作为工业化快速发展地区,长株潭城市群耕地景观变化的剧烈程度明显高于长江中游经济带内的其他两大城市圈(群)。(4)不同尺度耕地景观格局在数量、面积、聚集度、多样性方面差异较大。而城市圈(群)作为省内重点发展区域,其耕地景观格局及其变化与其所处省份大致相同。

The aim of this study was to explore the evolution of farmland landscape in the middle reaches of the Yangtze River,which helped to interpret the status of the farmland utilization from the regional level and provide important reference for the protection of farmland and ecological environment. Based on the method of landscape pattern index analysis and mathematical statistics,the changes of farmland landscape during 1995-2014 were studied by analyzing 10 landscape indices at class level and landscape level. In this study,we selected three spatial scales： urban agglomeration,province and basin. The results showed that：（ 1） From 1995 to 2014,the total farmland area decreased significantly in the middle reaches of the Yangtze river,and the average rate was 308. 21 km^2/a. Among them,the average reduction rate of Hubei,Hunan and Jiangxi was 180. 03,48. 19 and56. 16 km^2/a; the average reduction rate of Wuhan Urban Agglomeration,Chang-Zhu-Tan Urban Agglomeration and Poyang Urban Agglomeration was 180. 03,48. 19 and 56. 16 km^2/a,respectively.（ 2） The direction and extent of farmland landscape changes were quite different in Hubei,Hunan and Jiangxi. The connectivity of farmland in Hunan showed an increasing trend during 1995-2005 while decreasing during 2005-2014,and the landscape fragmentation first ascended and then descended throughout the study period,contrary to the variation in Hubei and Jiangxi in this two periods. In addition,the changes in connectivity and fragmentation of landscapes in Hunan were most dramatic.（ 3） The direction and extent of farmland landscape changes differed in several aspects in three urban agglomerations. With the rapid development of industrialization,the landscape of ChangZhu-Tan Urban Agglomeration changed dramatically,and its degree of variability well beyond the other two urban agglomerations in the middle reaches of the Yangtze river.（ 4） The quantity,area,aggregation degree and diversity of farmland landscape were significantly different in each scale. As the key development area in the province,the landscape pattern and its change of the urban agglomeration were roughly the same as those of the provinces where they are located.