基于景观格局的宁夏星海湖生态风险时空分异

Spatial and Temporal Variation of Ecological Risk of Xinghai Lake in Ningxia Based on Landscape Pattern

以西北干旱区城市湖泊——星海湖为研究区域,基于2005、2011、2016年遥感影像数据,利用景观格局指数和景观脆弱度构建了湿地生态风险指数。在ArcGIS等软件平台,利用空间插值及空间自相关方法分析星海湖生态风险时空分异特征。结果显示:1)2005—2016年星海湖湿地景观格局发生了明显变化,所有景观类型面积均存在不同程度波动变化,其中受人类活动影响较大的建设用地、草地、湿地植被破碎化趋势增强,区域景观稳定性降低。2)研究区生态风险分布与景观类型密切相关,3个时期星海湖湿地主要生态风险均包含中等风险,低风险区面积占比由17.6%降至不足1%,较高风险区面积呈明显上升趋势,经历了由中等及以下风险向中等风险和较高风险的转变。3)研究区生态风险存在空间聚集效应,聚集区域的分布与景观类型分布相关。城市湖泊湿地受人类活动影响显著,亟需加强湿地生态风险管理与保护。

Taking Xinghai Lake,a typical urban lake in arid area of Northwest China,as the research area,and based on remote sensing images in 2005,2011 and 2016 as data sources,the wetland ecological risk index was constructed by using landscape pattern index and landscape vulnerability index.Based on ArcGIS and other software platforms,spatial interpolation and spatial autocorrelation methods were used to analyze the spatial and temporal characteristics of ecological risk in Xinghai Lake.The results showed that:(1)The landscape pattern of Xinghai Lake wetland changed significantly from 2005 to 2016.The area of all landscape types fluctuated in varying degrees.The trend of fragmentation of construction land,grassland and wetland vegetation,which were greatly influenced by human activities,was increasing while the stability of regional landscape was decreasing.(2)The distribution of ecological risk in the study area was closely related to landscape types.The main ecological risk of Xinghai Lake wetland in the three periods included moderate risk.The proportion of low-risk area decreased from 17.6%to less than 1%.The higher risk showed an obvious upward trend,and experienced a transition from below medium risk to medium risk and high risk.(3)The ecological risk of the study area had spatial aggregation effect,and the distribution of the aggregation area was related to the distribution of landscape types.Urban lake wetlands are significantly affected by human activities,so it is urgent to strengthen the management and protection of ecological risk of wetlands.