基于最小累积阻力模型的北京市生态用地规划研究

摘要

Ecological land planning places emphasis on protecting the structure and function of regional ecological systems and reinforcing the eco-environmental support capacity of social-economic development.Allowing for the comprehensive consideration of ecological security demands,air-quality improvement requirements,and livable city needs,we firstly identified pivotal ecological land based on an intcgrated evaluation of the ecological importance of Beijing City.Ecological importance was evaluated using an analysis of ecological quality and function.The key areas,with great importance to the improvement of the atmospheric and residential environments,were identified.Ecological quality was based on vegetation coverage and biomass using 3S technology.The ecological functions of water conservation,soil conservation,and biodiversity maintenance were evaluated using the integrated water storage capacity calculation,the universal soil loss equation,and InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) model,respectively.Forest resource inventory data were used to identify key areas with great importance to the improvement of atmospheric environmental quality.Distribution maps of forest parks,nature reserves,water source conservation areas,and scenic spots were used to identify key areas of great importance to the improvement of residential environments.Pivotal ecological land was finally identified by spatial overlay analysis using the ArcGIS 10.1 software platform.Secondly,we considered the pivotal ecological land as the "source," and built upon the resistance surface according to land use type,distance to roads,and distance to settlements to run the minimum cumulative resistance model and simulate the spatial expansion of ecological land.From this,we established three planning scenarios for ecological land.Thirdly,ecological protection effectiveness under different planning scenarios was evaluated by analyzing landscape patterns,protection levels for ecological functions,and conflicts with actual construction areas.Landscape patterns were analyzed by calculating landscape indexes using Fragstats 4.2 software.The protection level of ecological functions was determined by weight calculations.Conflicts with actual construction areas were based on spatial analysis statistics.Finally,we chose the best planning scenario,and determined the minimum scale and optimized spatial pattern for ecological land.The results showed that 1) the area of pivotal ecological land in Beijing City covered 9879 km2,accounting for 60.20％ of the total area of the city;2) the area of minimum ecological land was 12417 km2,accounting for 75.67％ of the total area of the city;3) the area of minimum ecological land in plain terrain was 2944 km2,accounting for 46.45％ of total plain terrain area,and was mainly located in the surrounding transition areas of the construction areas;and 4) the area of the minimum ecological land in mountainous areas was 9473 km2,accounting for 94.05％ of total mountainous area.The minimum ecological land area in this study was larger than that in other similar studies.Our study took not only the demand of ecological security into consideration but also the major environmental problems and urban construction target areas of Beijing City.The key areas with great importance to the improvement of atmospheric and residential environmental conditions were analyzed together and given ecological importance.Therefore,the minimum scale and optimized spatial pattern of ecological land in this study was more practical and corresponded with the development demands of the city.%生态用地规划强调对区域生态系统结构与功能的保护,增强社会经济发展的生态环境支撑能力.从保障首都基本生态安全、改善大气环境质量、建设宜居城市的角度出发,通过对北京市生态重要性进行综合评价,明确北京市重要生态用地空间分布特征.在此基础上,采用最小累积阻力模型(MCR),以重要生态用地为“源”,以土地覆被类型、距道路距离和距居民点距离作为阻力因子生成阻力面,模拟重要生态用地空间扩张过程,进而设置生态用地规划情景,并从景观连通性、生态功能保障度及与现状建设用地冲突情况等3个方面对不同情景下的生态用地规划方案进行保护效能评价,最终提出北京市生态用地的适宜规模和优化布局方案.研究结果表明:北京市重要生态用地总面积为9879 km2,占市域总面积的60.20％;生态用地的适宜规模为12417 km2,占市域总面积的75.67％,其中,平原区生态用地的适宜规模为2944 km2,占平原区总面积的46.45％,主要分布于建成区的外围过渡地带;山区生态用地的适宜规模为9473 km2,占山区总面积的94.05％.