城市化和生态文明建设对喀斯特山地城市景观生态风险的影响评价——以贵阳市花溪区为例

Evaluation of the Impact of Urbanization and Ecological Civilization Construction on Landscape Ecological Risk in Huaxi District of Guiyang Characterized as Karst Mountain City

[目的]探究喀斯特山地城市贵阳市花溪区近年来景观格局及景观生态风险动态变化,为喀斯特山地城市生态环境保护与改善和生态安全格局构建等提供基础和依据。[方法]以研究区2008年、2013年和2018年三期景观类型空间数据为主要数据源,根据景观生态风险评价的基本架构,基于ArcGIS ModelBuilder平台构建一体化景观生态风险综合评价模型,分析研究区近年来景观生态风险时空变化特征。[结果](1)2008—2018年,花溪区景观格局变化剧烈,耕地面积缩减216.00 km^(2),林地和建设用地面积分别扩大127.09 km^(2),82.80 km^(2)。城市化和生态建设呈明显的空间异质性,总体表现出随距城市中心距离变化而呈现出“中心城市化、四方生态化”变化趋势。(2)2008—2018年,花溪区景观生态低风险区面积显著增大,约164.81 km^(2),与较低风险区缩减量大致相当,中等风险至高风险区波动变化,变化量较小。生态保护工程对研究区景观生态风险缓解做出贡献,城市化进程因其在喀斯特山地城市不同区域的发展形式不同,表现为城市中心缓解而城市边郊加剧。(3)基于ModelBuilder建立的景观生态风险计算工具可提升评价的效率,且具有通用性,可为不同地区景观生态风险评价提供技术支撑。[结论]花溪区呈典型的喀斯特“城—山”镶嵌格局,景观格局变化及其生态风险效应受快速城市化和生态工程建设影响较大,并存在明显的时空异质性。今后应着重于城镇布局合理规划和人类活动调控,并继续开展植被保护和生态重建,促进经济发展与生态改善“双赢”的可持续发展。

[Objective]The aim of this study is to explore the dynamic changes of landscape pattern and landscape ecological risk in Huaxi District,Guiyang City,a karst mountain city,and provide a basis for the protection and improvement of ecological environment and the construction of ecological security pattern of karst mountain cities.[Methods]The spatial data of landscape types in 2008,2013,2018 were selected as the main data sources.Integrated landscape ecological risk comprehensive assessment model was constructed based on ArcGIS ModelBuilder platform according to the basic framework of landscape ecological risk assessment.The spatial-temporal changes of landscape ecological risk in the study area in recent years were analyzed.[Results](1)From 2008 to 2018,the landscape pattern of Huaxi District changed dramatically,the area of cultivated land decreased by 216.00 km^(2),and the areas of forest land and construction land expanded by 127.09 km^(2)and 82.80 km^(2),respectively.Urbanization and ecological construction showed obvious spatial heterogeneity,so that the overall study area showed the change trend of‘central urbanization and four-way ecology’with the variation of distance from the city center.(2)From 2008 to 2018,the area of the lowest-risk landscape ecological area in Huaxi District significantly increased by 164.81 km^(2),which was roughly equivalent to the reduction of the lower-risk area,and the fluctuation change of the range the medium-risk to highest-risk area was relatively small.Ecological protection projects had contributed to the mitigation of landscape ecological risk in the study area.The different forms of urbanization development in different areas of karst mountain cities made the landscape ecological risk manifested as the mitigation of urban centers and the intensification of urban suburbs.(3)The landscape ecological risk calculation tool has high efficiency and strong universality that is not restricted by regions and landscape types,can provide technical support for landscape ecological risk assessment in different regions.[Conclusion]Huaxi District presented a typical karst‘city-mountain’mosaic pattern,and the change of landscape pattern and its ecological risk effect were greatly affected by rapid urbanization and ecological engineering construction,and there was obvious spatiotemporal heterogeneity.In the future,more attention should be paid to the rational planning of urban layout and the regulation of human activities,vegetation protection and ecological reconstruction should be continually implemented,so as to promote the win-win benefits of sustainable development of economic development and ecological improvement.