经济快速增长区城市用地扩展的生态风险评估及其防控研究--以内蒙古呼和浩特市为例

Hohhot is the capital of Inner Mongolia Autonomous Region and it is the frontier city which opens to north and west. With economic growth and accelerate development of urbanization process in recent years, the urban land in Huhhot is expanding rapidly to the surrounding areas. Cultivated land decrease, air pollution, heat island effect, landscape fragmentation problems which caused by the land expansion has led to the intensification of regional ecological risk. It has great significance for city sustainable development which in the ecological fragile zone to take the ecological risk assessment of urban land expansion as cutting point and to study on the simulation regulation of urban land expansion and the precaution control of ecological risk. This project will take Hohhot city as the research object where the process of urbanization is relatively rapid but the ecological environment is sensitive and fragile. Based on space-time analysis of change characteristics on urban land expansion and land use structure, the project will analyze the ecological environment effect of land use pattern change from the change perspective of resources, environment, landscape pattern, service value and ecological safety. Basing on ecological risk identification and driving factor analysis of urban land expansion, the spatial and temporal evaluation and visualization of ecological risk was studied. Through the research on regulation of urban land expansion and the simulation, prediction, early warning and scenario analysis of ecological risk, the ecological risk district prevention and control and avoidance mechanism of urban land expansion was constructed. It aims to explore the driving mechanism, response mechanism and control strategy between urban land expansion and ecological risk, and to provide the basis for the construction of land use security pattern.

呼和浩特市是内蒙古自治区首府及国家向北、向西开放的前沿城市。近年来随经济增长及城市化进程的加快，其城市用地扩展迅速，由此引发的耕地锐减、大气污染、热岛效应、景观破碎等问题已导致区域生态风险的加剧。以城市用地扩展所致生态风险评估为切入点，开展城市用地扩展模拟调控及其生态风险预警防控研究，对生态脆弱区城市持续发展意义重大。本项目以城市化进程迅速而生态环境敏感脆弱的呼和浩特市为研究对象，在对城市土地扩展及其用地结构演变特征进行时空分析的基础上，从资源、环境、景观格局、服务价值与生态安全变化等层面，分析用地格局演变的生态环境效应；基于城市用地扩展的生态风险识别及驱动因子剖析，开展生态风险的时空评估与可视化研究；通过城市用地扩展调控及其生态风险模拟、预测、预警与情景分析，构建生态风险分区防控与规避机制。其旨在探寻城市用地扩展与生态风险间的驱动机制、响应机理与调控策略，为构建土地利用安全格局提供依据。

呼和浩特地处环渤海经济圈、西部大开发、振兴东北老工业基地三大战略交汇处，是呼包银榆经济带与呼包鄂榆城市群的核心城市及“一带一路”战略发展的重要节点。因经济快速发展与人口迅速增加，呼和浩特城区用地不断扩张，使其用地结构与景观格局发生变化，导致生态环境破坏与生态系统退化，影响城市持续发展与生态安全。因其特殊的生态区位与战略地位，呼和浩特社会经济发展与环境质量优劣对内蒙古乃至全国有重要影响，开展其城市空间扩展及生态风险评估与防控研究，对促进生态脆弱区城市土地优化利用，意义重大。基于此，本项目在分析呼和浩特城市土地扩展及其用地结构演变特征的基础上，探究城市扩展的生态环境效应；基于城市扩展的生态风险识别及驱动因子剖析，开展生态风险时空评估与预警研究；通过城市用地扩展与生态风险演变的耦合分析，进行城市空间扩展模拟与调控研究；依据城市扩展的外部约束与内生机制，划定城市增长边界，构建基于生态安全的城市空间管制与生态风险防控策略。研究表明：1977~2017年，呼和浩特城市建成区面积从34.59km2扩展到274.10km2，具有加速扩张的阶段性特征，经济增长、交通建设、投资拉动、工业化与城市化是城市扩展的主导因素；伴随城市用地扩张，城市生态用地减少19.05%，排污总量增加1.33倍，热岛效应指数升高0.78倍，环境质量指数下降4.97%，生态压力指数增加2.75倍；城市生态风险综合指数由0.30增至0.58，生态风险等级由低级发展为中等水平，未来一定时期内城市生态风险仍将处于“中警”状态；城市建设用地面积与生态风险指数间的关联度达0.6073，属中等关联，二者间的耦合关系处于颉颃时期，城市空间扩展与生态风险加剧具有较强的时空耦合性；“生态经济型情景”是城市用地扩展的最优方案，划定城市增长刚性边界为650.29km2，弹性边界为550.06km2；确定城市生态源地424km2，生态廊道15条，生态战略点11个，构建生态安全格局为“一环、两带、三区、四廊、多心”，其中，保合少镇为禁止开发区，榆林镇、攸攸板镇及黄合少镇为限制开发区，金河镇、小黑河镇、新城区为重点开发区，赛罕区、玉泉区、回民区为优化开发区。本研究不仅可为呼和浩特城市规划、土地管理、生态建设与风险防控提供理论基础与决策依据，还可为生态脆弱区实现生态修复与环境保护提供实践指导，具有较强的针对性、实用性和推广价值。