四川凉山州孙水河流域耕地撂荒时空格局分析OA北大核心CSTPCD

[Objective]The aims of this study are to extract long-term and precise monitoring of abandoned farmlands,to understand the spatiotemporal distribution patterns of abandoned farmlands in river basins,and to provide data support for the management of land resources and the strategic planning of rural revital-ization in Liangshan Prefecture.[Methods]The Sunshuihe River Basin in Liangshan Prefecture was taken as the research area.The Classification and Regression Tree(CART)model was used to extract abandoned farmlands from 2009 to 2016,and the spatiotemporal pattern and evolution dynamics of abandoned farmland in the past eight years were analyzed using the standard deviation ellipse method.[Results](1)Farmland abandonment in the basin showed two changing trends during the study period:slow decrease from 2009 to 2011 and rapid increase from 2012 to 2016.Abandoned farmlands mostly distributed in the middle and high mountain areas and gradually decreased in the valley plain.The average abandoned area for the entire river basin was 5 357.88 hm2,and the maximum abandonment rate(24.50% )was observed in 2016.The average annual abandoned area followed the order:middle reaches(2 260.50 hm2)>upstream(1 716.01 hm2)>downstream(1 381.88 hm2).The average annual abandonment rate increased with stream reaches:upstream(19.17% )>middle reaches(15.46% )>downstream(8.50% ).(2)The standard deviation ellipse distribution of abandoned farmland showed two stages of development.From 2009 to 2012,it showed the distribution of'southeast-northwest'.After 2013,the center of gravity moved back,and the abandoned land was more concentrated.(3)Along topographic and proximity factors,abandoned farmland mostly distributed with an altitude of>2 800 m,and a slope gradient of 15°～25°,and 500 m away from the river system.[Conclusion]The spatiotemporal pattern of abandoned farmlands can be influenced by various factors such as topographical conditions,production levels,and political factors.In the future,it is important to enhance the in-depth study of the impact mechanisms of human activities and natural conditions on the land abandonment.