喀斯特山区城市边缘区生态风险时空演变研究——以贵州省贵阳“两湖一库”地区为例

Study on spatial and temporal evolution of urban fringe ecological risk in Karst area based on LUCC: case of two lakes and one reservoir area in Guiyang,Guizhou Province

为揭示土地利用变化对喀斯特山区城市边缘区生态风险影响,选择贵阳"两湖一库"地区18个乡镇作为研究区域,利用1973年MSS影像、1993年TM影像、2001年ETM影像和2010年的ALOS影像获取"两湖一库"土地利用信息,从风险源的危险性、风险受体的抵抗力稳定性上构建土地利用生态风险评价模型,以乡镇行政区划为基本单元,量化评估"两湖一库"地区生态风险时空变化特征。研究表明:"两湖一库"地区40 a来生态风险指数整体先增加后减小,1973~1993,1993~2001年两个年段分别增加279.06%,21.90%;2001~2010年段减少115.52%。生态风险单项指标除土地利用破碎化程度不断增加外,其余指标都在恶化后有所好转。"两湖一库"地区生态风险状况空间差异显著,生态修复以及城市扩张的双向影响导致生态风险变化在空间上分异,具体表现为建成区所在南明区、云岩区以及湖区所在红枫湖镇、夏云镇、高峰镇生态风险值增加后基本维持不变,而建成区周围的久安镇、石板镇、金竹镇等乡镇生态风险值逐渐降低。

To reveal the impact of land use change in urban fringe in karst region on ecological risk, choosing 18 towns in the 2 lakes and 1 reservoir area in Guiyang, Guizhou Province and based on the land use information in this region from MSS imagine in 1973, TM imagine in 1993, ETM imagine in 2001 and ALOS imagine in 2010, the ecological risk assessment model of the land use was built in terms of the risk sources, resistance stability of risk receptor, and further the temporal and spatial variation of risk characteristics in the region were quantitatively assessed by taking the township administrative divisions as basic unit. The research results showed that： （1） The regional ecological risk index for the past 40 years generally increased firstly and then decreased, with. increment ratio of 279.06% , 21.90% in 2 periods of 1973 - 1993 and 1993 - 2001, and with a decrement ratio of 115.52% in period of 2001 -2010. Except for the continuous increment of land use risk index due to land fragmentation, the other indices of ecological risk were improved after deterioration. （2） The spatial difference of the ecological risk status in the region was notable, the dual influence of ecological restoration and urban expansion had resulted in a spatial differentiation of eco-logical risk, especially the ecological risk in the built - up areas of Nanming District, Yunyan District and the townships of Hongfenghu, Xiayun increased and then remained basically unchanged, however the risks of the area around the built areas such as townships of Jiuan, Shiban, Jinzhu etc. decreased gradually.