黄河下游城市济南区域景观生态风险时空演变分析

Analysis on Spatiotemporal Evolution of Landscape Ecological Risk in the Jinan Region of the Lower Reaches of the Yellow River Cities

为探究黄河下游城市生态风险变化以及城市建设对黄河沿岸风险变化的影响,以黄河下游城市济南区域为研究区,根据2000、2010、2020年影像数据,采用生态风险指数与空间分析法,分析黄河下游城市济南区域的生态风险时空演变特征。结果表明,1)2000-2020年,研究区景观类型演变较明显,其中,耕地、林地和草地面积呈减少趋势,且景观优势度降低;建筑用地面积为持续增加,景观优势度提高;水体表现为先减后增,破碎度和分离度先增加后减少。2)2000-2020年黄河下游城市济南区域景观生态风险整体呈下降趋势,低、较低和中风险区的面积显著增加,较高和高风险区面积逐渐减少。空间分布上,黄河沿岸生态等级向南北纵向依次递减,但在城市边缘部分依然生态风险较高。3)研究区生态风险等级的转换类型多样,整体以高等级向低等级转化为主,前10 a减小速率大于后10 a,但在2010-2020年高生态风险有所增加。总之,黄河下游城市济南区域景观生态风险等级逐渐下降,城市有序扩张对降低风险等级具有积极影响,但未利用地的开发会增加景观生态风险,建议在维持现有城市景观生态建设的同时,继续降低人为干扰,注重景观资源的合理开发,实现可持续发展。

The paper took the Jinan region along the Yellow River as the study area and analyzed the spatial and temporal evolution characteristics of ecological risk in the Jinan region of the lower reaches of Yellow River cities based on the image data in 2000,2010 and 2020,with the method of ecological risk index and spatial analysis to explore the ecological risk changes in the Jinan region along the Yellow River and the role and influence of urban area construction on the Yellow River corridor.The results showed that 1)during the period from 2000 to 2020,the landscape types in the study area evolved obviously,in which the areas of cultivated land,woodland and grassland showed a decreasing trend,and the landscape dominance decreased.The construction land area continued to increase,and the landscape dominance was improved.The water body first decreased and then increased;the area of water bodies decreased and then increased,with fragmentation and separation increasing and then decreasing.2)The landscape ecological risk in the last 20 years along the Jinan region of the Yellow River,the landscape ecological risk as a whole tended to decline,with the area of low,lower and medium risk areas increased significantly and the area of high and higher risk gradually decreased.In terms of spatial distribution,the ecological level along the Yellow River decreased in the north-south direction,but the ecological risk was still higher in the urban fringe.3)The transformation of ecological risk levels in the study area was of various types,and the transformation from high to low level was the main one.In general,the decrease rate in the first 10 years was greater than that in the last 10 years,but the high ecological risk increased from 2010 to 2020.In a word,the landscape ecological risk level of cities in the lower reaches of the Yellow River and Jinan region was gradually declining,and the orderly expansion of cities had a positive impact on reducing the risk level.It is suggested that while maintaining the existing urban landscape ecological construction,we should continue to reduce human interference and put emphasis on the rational development of landscape resources to achieve sustainable development.