城市扩张情景下苏南水网景观生态风险评价与生态安全格局构建——以苏州白蚬湖片区为例

Landscape Ecological Risk Assessment and Ecological Security Pattern Construction in the Southern Jiangsu Water Network Area under the Urban Expansion Scenario Simulation: A Case Study of the Baixian Lake Area in Suzhou

伴随快速城镇化发展,人工建设活动频繁,苏南水网地区面临一系列生态环境问题,生态风险日益突出,基于景观生态风险评价构建生态安全格局是提升区域生态环境稳定性的有力途径。研究以苏州市白蚬湖片区为例,借助景观格局指数构建景观生态风险评价模型,剖析研究区2010~2020年景观生态风险时空分异特征,基于CA-Markov模型模拟城市扩张情景下土地利用格局并预测其景观生态风险空间分布,探讨时空动态演变下生态安全格局构建研究。结果表明:(1)2010~2020年土地利用格局变化显著。建设用地面积持续扩张,面积上升了59.32 km^(2);耕地、水域面积分别下降17.98、53.61 km^(2);林草地面积小幅上升,共计增加12.27 km^(2)。2030年城市扩张情景模拟下建设用地增幅最大,面积增加134.14 km^(2);耕地与水域面积分别缩减174.06、6.76km^(2);林地、草地面积共上升46.68 km^(2)。(2)2010~2020年景观生态风险总体呈上升趋势,中高风险面积占比共增加6.55%,低、较低风险面积有所下降,占比分别减少4.62%、1.92%。2030年城市扩张情景模拟下景观生态风险中等级以上区域逐步扩张,其中较高风险面积增加最多,占比上升10.12%,较低与低风险面积占比缩减19.14%。(3)基于2020年现状与2030年城市扩张情景模拟下生态安全格局构建结果,共识别研究区生态源地23个,生态廊道50条,生态节点21个,最终综合构建时空动态变化下的生态安全格局。研究结果可为保护水网地区生态环境、抵御外界生态风险提供理论依据,对促进区域生态安全发展有一定参考意义。

With the rapid urbanization and frequent artificial construction activities,the water network area in southern Jiangsu Province is facing a series of ecological and environmental problems,and ecological risks are becoming increasingly prominent.Constructing an ecological security pattern based on landscape ecological risk assessment is a powerful way to enhance the stability of the regional ecological environment.In this study,we took the Baixian Lake area of Suzhou as an example,and we adopted the landscape pattern index to construct a landscape ecological risk assessment model.The spatiotemporal differentiation characteristics of landscape ecological risks were analyzed in the study area from 2010 to 2020.We simulated the land use pattern under urban expansion scenarios based on the CA-Markov model,and predicted the spatial distribution of landscape ecological risks.On this basis,we explored the construction of ecological security pattern under the spatiotemporal dynamic evolution.The results indicated that:(1)The land use pattern changed significantly from 2010 to 2020.The area of construction land increased by 59.32 km2,while the area of farmland and water area decreased by 17.98km2 and 53.61km2,respectively.The area of forest land and grassland slightly increased by 12.27 km2.The urban expansion scenario simulation indicated that the construction land would extend the most by 2030,with an increase of 134.14 km2.The area of farmland and water area would decrease by 174.06km2 and 6.76km2 respectively.The total area of forest land and grassland would increase by 46.68km2.(2)From 2010 to 2020,the landscape ecological risk continued to increase.The proportion of medium risk and high risk areas increased by 6.55%in total,while the low and medium-low risk areas decreased by 4.62%and 1.92%respectively.The simulation of urban expansion in 2030 indicated that the proportion of medium-high ecological risk areas would increase by 10.12%,while the medium-low and low risk areas would decrease by 19.14%.(3)Based on the land use pattern in 2020 and the ecological security pattern under the urban expansion scenario simulation in 2030,we identified 23 ecological source areas,50 ecological corridors,and 21 ecological nodes in the study area.A comprehensive ecological security pattern under spatiotemporal dynamic changes was constructed.The results may provide theoretical basis for protecting the ecological environment in water network areas and for resisting external ecological risks,which is significant for promoting regional ecological security development.