广西石漠化地区土地利用空间变化的生态风险研究

目的]利用2000年、2005年、2010年、2015年广西轻度及以上石漠化的69个区/县土地利用数据,分析其土地利用时空变化特点,揭示其变化对该区域土地生态风险的影响。方法]基于GIS支持,采用土地利用动态变化度、土地转移流、土地生态风险指数(RSI)等对研究区土地生态风险的异质性特征进行定量分析。结果](1)2000—2015年广西石漠化地区土地利用动态度呈逐渐增大趋势,土地利用动态度变化,反映出研究区土地利用变化较频繁。(2)耕地、林地、草地、建设用地4类用地转移的数量与方向决定着广西石漠化地区土地利用变化的特征。(3)2000—2015年广西石漠化各区/县土地生态风险程度略微增大,南部的贵港、南宁是生态重警区,研究区的土地生态安全有待进一步改善。(4)土地生态风险指数与土地利用类型变化的活跃程度呈正相关。结论]研究区未来土地利用,应进一步优化土地资源配置,加强生态环境保护,提高土地利用综合效益。

ECOLOGICAL RISKS CAUSED BY LAND USE VARIATIONS IN THE ROCKY DESERTIFICATION MOUNTAINOUS AREA IN GUANGXI PROVINCE

By using land data in year 2000, 2005, 2010, 2015 of the 69 districts/counties containing light to severe rocky desertification in Guangxi province, this research aims to analyze the spatiotemporal variation of land use change and reveal the relationship between land use change and the evolution of land ecological environment. With the support of GIS, this research made a quantitative analysis of the temporal and spatial characteristic of land use ecological risk by adopting the criteria of land use dynamic change, the flow of land use change and the ecological risk index (ERI). The results were showed as follows. Firstly, the dynamic degree of land use in rocky desertification area of Guangxi had increased slightly from 2000 to 2015, showing land use changes frequently. Secondly, magnitude and direction of transformation among cultivated land, forest land, grass land and construction land were the controlling factors which determined the characteristics of land use change in those areas. Thirdly, the degree of ecological risk had gradually increased from 2000 to 2015, among those areas Nanning was ecological serious warning area. And the land ecological security needed to be further improved in the study area. Finally, the ecological risk index of land was positively correlated with the activity level of land use change. In summary, this research provides insight to the allocation of land resources and scientific guidelines to the environmental protection in the rocky desertification area, strengthen the protection of ecological environment and improve the comprehensive benefit of land use.