山区耕地破碎化时空演化分析--以贵州省为例

Analysis on the Spatiotemporal Evolution of Cultivated Land Fragmentation in Mountainous Areas-A Case Study of Guizhou Province

耕地是人类生存发展的基本资料,对山区耕地破碎时空演化特征进行探究,以期为山区耕地合理利用提供相关参考。以贵州山区为研究区,采用综合景观指数法,结合Fragstats 4.2和GIS空间分析工具,在获取最佳分析尺度基础上,分析山区耕地破碎时空演化特征。结果表明:(1)150 m粒度和600 m幅度是贵州省耕地破碎化分析的最佳尺度;(2)2000-2018年耕地破碎化略有加重,呈现出低破碎在中心,较低破碎环绕,一般和高破碎广泛镶嵌,剧烈破碎填充的分布格局;(3)19 a间,整体以一般和高破碎为主,占耕地总面积的51%以上,剧烈和一般破碎化次之,占32%左右,低破碎化面积最少,为13.69%~14.53%;(4)空间上,贵阳市、黔东南州、黔南州和铜仁市及六盘水市等破碎程度高,遵义市、毕节市、安顺市和黔西南州破碎低;(5)时间上,各区域破碎变化趋势有所差异,黔南州和贵阳市破碎化有所降低,其余市(州)耕地破碎化程度仍在增加。综上,山区耕地破碎具有一定的垂直梯度分异;自然条件对山区耕地破碎空间分布有着基础性作用,人类活动是其变化的核心驱动力。

Cultivated land is the basic resource for human survival and development.We explored the spatiotemporal evolution characteristics of cultivated land fragmentation in mountainous areas in order to provide relevant references for the rational utilization of cultivated land in mountainous areas.Taking the mountainous area of Guizhou as the research area,on the basis of obtaining the optimal analytical scale,we adopted integrated landscape index method,Fragstats 4.2 and GIS spatial analysis tool to analyze the temporal and spatial evolution characteristics of cultivated land fragmentation in mountainous areas.The results show that:(1)150 m grain size and 600 m amplitude are the best scales for analysis of farmland fragmentation in mountainous areas;(2)from 2000 to 2018,the fragmentation of cultivated land in Guizhou showed a distribution pattern of low fragmentation in the center and low fragmentation surrounding the low fragmentation;the general fragmentation and high fragmentation were widely inlaid and clustered,and the distribution pattern of gypsophila was violently broken;(3)in 19 years,the overall cultivated land in Guizhou was dominated by normal and high fragmentation;these two types of fragmentation together accounted for more than 51%of Guizhou′s cultivated land area;the second was severe fragmentation and general fragmentation,which together accounted for about 32%;the area of low fragmentation was the least,ranging from 13.69%to 14.53%;(4)in terms of space,the degrees of fragmentation of cultivated land in Guiyang City,Qiandongnan Prefecture,Qiannan Prefecture,Tongren City and Liupanshui City were high,while those of Zunyi City,Bijie City,Anshun City and Qianxinan Prefecture were low;(5)from the perspective of time,the change trend of the degree of cultivated land fragmentation in each region was different;the fragmentation of cultivated land in Qiannan Prefecture and Guiyang City had decreased,while the degrees of cultivated land fragmentation in other cities(prefectures)were still increasing.To sum up,cultivated land fragmentation in mountainous areas had a certain vertical gradient differentiation.Natural geographical conditions play a fundamental role in the formation and spatial distribution of cultivated land fragmentation in mountainous areas,and human activities are the core driving force for the fragmentation of cultivated land in mountainous areas.