【摘要】 喀斯特高原景观生态风险变化研究,对建立生态风险预警机制、降低生态风险概率和促进喀斯特高原地区景观格局优化具有重要意义.以2009、2014和2017年的3个时期高分辨率遥感影像为景观格局分析主要数据源,构建景观生态风险评价模型,研究了草海流域景观生态风险时空变化及其空间模式.结果表明,2009—2017年间,研究区景观结构变化较大,耕地和灌草地景观类型面积均呈减少趋势,林地、沼泽地、建设用地和水域景观类型面积呈增加趋势.2009—2017年间,高和较高生态风险主要分布在流域北部、东北部,中生态风险主要分布在流域东部、西南部,较低生态风险主要分布在流域南部-西部-西北部段,低生态风险主要集中在湖泊及其周围.2009—2017年间,研究区生态风险以低和较低生态风险为主,占流域面积的72.38%以上;2009—2014年间,高生态风险、较高生态风险和中生态风险的面积呈不同程度增加;2014—2017年间,高生态风险、较高生态风险和中生态风险的面积明显减少.2009—2017年期间,研究区景观生态风险存在显著空间正相关,"高-高"和"低-低"聚集是主要的生态风险集聚模式,"低-高"或"高-低"零散分布.更多还原

【Abstract】 Studies on the changes in spatial pattern of landscape ecological risk on karst plateau zone play important roles in establishing the ecological risk warning mechanisms, minimizing the risk of ecological environment and optimizing the landscape pattern of karst plateau zone. Based on the high-resolution remote sensing images obtained in 2009,2014 and 2017, this work constructed an evolution model of landscape ecological risk pattern to analyze the temporal and spatial changes and spatial mode of landscape ecological risk on Caohai watershed. The results showed that the landscape structure in the study area significantly changed during 2009 to 2017. The areas of cultivated land and shrub land showed a decreasing trend, while the areas of forest land, marsh land, construction land and waters showed an increasing trend. During 2009 to 2017, high ecological risk and relatively high ecological risk were mainly distributed in the north and northeast of the watershed. Moderate ecological risk was mainly distributed in the eastern and southwestern of the watershed. Relatively low ecological risks was mainly distributed in the south-west-northwest of the watershed and low ecological risks was mainly concentrated around the lake area of the watershed. During 2009 to 2017, the ecological risks of the study area were at low and extremely low level, which accountd for more than 72.38% of the study area. During 2009 to 2014, the area of high ecological risk, relatively high ecological risk and moderate ecological risk increased to some extent, but they significantly decreased during 2014 to 2017. There was significant spatial positive correlation between the landscape ecological risks of the watershed during 2009 to 2017, the "high-high" and "low-low" accumulations were the main ecological risk accumulation mode, the "low-high" or "high-low" scattered distribution.更多还原