| With the development of social economy the acceleration of urbanization and agricultural modernization,the spatial pattern of settlement land has changed.The landscape pattern of settlement land in karst mountain area is different from that in plain area.Under this special geographical environment,how to optimize the settlement land reasonably is a problem,which needs to be solved urgently in the present land space planning.The study on the change characteristics and driving factors of settlement land can effectively evaluate and optimize the settlement land and provide scientific guidance for the sustainable development of regional settlements and the construction of new-type urbanization.This paper takes Huanjiang Maonan Autonomous County as the study area,which is a typical county in karst mountain area.The land use data of 2005,2010 and 2015were obtained by establishing the remote sensing image interpretation mark and human visual interpretation.Based on GIS,Fragstats4.2 software platform,GIS spatial analysis,land transfer matrix method,landscape index method,KDE method were employed to analyze the characteristics of settlement change of 2005,2010 and 2015 in Huanjiang County and reveal its the spatial change law of settlement land;the driving force factors of settlement land change were analyzed by Geo-detector,and the spatial distribution of settlement land in 2015 was evaluated and optimized by MCR model,and some suggestions were put forward.The results show that:(1)In 2005,2010 and 2015,the settlement area was 5228.10 hm~2,5905.65 hm~2and 7080.68 hm~2,accounting for 1.14%,1.29%and 1.54%of the total area respectively.The settlement land area showed a trend of growth year by year and it was mainly distributed at the altitude of 0~350 m,the slope of 0~5°,0~1 km away from the river and 0~0.5 km away from the road.(2)Between 2005 and 2010,the transfer-in area of settlement land was1092.58hm~2,and the area of transfer-out was 584.60hm~2.In 2010-2015,the transfer-in area of settlement land was 3720.73hm~2 and the area of transfer-out was 2506.59hm~2.Settlement land was mainly converted from,cultivated land,grassland,woodland,water and other land;viewed from the evolution of landscape index,the landscape of settlement land presents a state of fragmentation,the aggregation of settlement landscape becomes smaller,and the shape of settlement patch tends to be irregular.(3)The high density settlement area of settlement land is mainly in the south-central area of Huanjiang County,concentrated in Sien Town,the south of Luoyang Town,east of Chuanshan Town and Minglun Town,and the high-density area takes Sien Town as the center,gradually decreases in all directions.The high density region increased obviously from 2010 to 2015,and the density structure of the settlements showed a trend from scattered distribution to cluster distribution.(4)The data of factor detection and ecological detection in Geo-detector show that altitude,population density,town distance and slope are the dominant factors of distribution of settlement density in Huanjiang county,net income per capita,the distance from the river and road are the second.The distance from the river has little effect on the settlement distribution;The interaction of slope,altitude and town,net income per capita and population density significantly increased the influence of settlement density.The results of interactive detection show that the interaction of multifactors has great impact on the change of settlement land and those factors show the result of two-factor enhancement and linear enhancement,which indicates that the change of settlement land is not the result of the action of a single factor.(5)According to the results of settlement evaluation and optimization of ecological security pattern,Huanjiang county is divided into four evaluation grades:core development area,transitional development area,adjustment development area and restricted development area.The adjusted development area has the largest settlement area of 3851.51hm~2,accounting for 54.53%,followed by the core development area of 1869.25hm~2,accounting for 26.45%,the transitional development area of 1073.94hm~2,accounting for 15.20%,and the restricted development area of268.82hm~2,accounting for 3.81%. |
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