基于武汉都市区1989年、2001年和2013年三期Landsat影像,选取景观格局指标反映绿地破碎化程度;利用梯度分析刻画绿地破碎度的空间格局及其对城市扩张的时空响应。景观格局指标总体特征表明:在城市扩张压力下,都市区绿地面积比例由82%减少为62%,绿地景观破碎度明显上升。梯度分析表明:1989-2013年,各缓冲带上建设用地比例逐年上升,而绿地面积比呈下降趋势;主城区建设用地破碎度下降,高破碎区向三环线外转移;耕地破碎度在各缓冲带上逐年上升,且随着与城市中心距离的增加,耕地破碎度降低;而林地破碎度略微下降,城市扩张对主城区外土地利用景观影响加剧。关联分析表明:城市扩张强度向主城区外推移加速,耕地破碎度变化强的区域向三环线外转移,而林地破碎度变化强度呈显著的时空分异特征;城市扩张在数量、格局及强度方面与绿地破碎化格局显著关联。研究结果可为研究区的城市规划和生态环境保护提供决策依据。
Here, six different landscape indicators were chosen to express the fragmentation extent of green land, and gradient analysis was adopted to analyze spatial patterns and spatial-temporal responses to urban expansion in the city of Wuhan, China. The overall characteristic of landscape pattern indicates that the area of green land decreased from 82% to 62% under the pressure of urban expansion in metropolitan areas and the extent of fragmentation of green land increased dramatically. We found that the construction land rate increased on all buffer zones, but the rate of green land showed a downward trend from 1989 to 2013. The fragmentation of construction land declined in the main city areas and high fragmented areas transferred to outside third ring road. The fragmentation of cultivated land increased on all buffer zones and fragmentation decreased with increasing distance to city center. Areas where cultivated land rapidly decreased corresponds to areas with high urban expansion, and areas with high fragmentation transfers were outside the third ring road. The fragmentation of forest land decreased slightly, the effect of urban expansion on land use landscapes outside the third ring road is increasing. Correlation analysis indicated that urban expansion intensity transfer is faster outside main city areas; high fragmentation change intensity of cultivated land transfers outside the third ring road; intensity of forest land change has spatial-temporal differentiation; and urban expansion is significantly correlated with green land fragmentation pattern through quantity, pattern and intensity. Outcomes of this study will be used by urban planning and ecological environment building in the study area.