基于不同种类生态安全的土地利用情景模拟

Land use scenario simulation with different types of ecological security

为解决中国城市化进程中日益严峻的生态和环境问题,合理确定未来土地利用结构和布局是关键,开展不同约束条件下的土地利用情景模拟研究对于科学规划和辅助决策具有重要意义。该文首先采用景观安全格局理论构建了曹妃甸新区综合生态安全格局,然后基于GIS和CA-Markov模型,提出了一种基于生态安全格局的土地利用情景模拟方法,并借助于2005年和2013年2期土地利用遥感解译图对曹妃甸新区生态安全格局保护与无生态保护2种土地利用情景下2021年的土地利用结构和布局进行了预测和模拟,结果显示,曹妃甸新区生态安全格局总面积为1 058.80km2,占区域总面积的53.53%,其中底线生态安全格局面积为312.67km2,占区域总面积的15.81%。生态安全格局保护情景下,底线生态安全格局范围内新增建设用地为0,且总生态安全格局范围内新增建设用地比无生态保护情景减少17.47km2。生态安全格局保护情景下,景观更趋于破碎化,景观的形状更趋复杂,建设用地与生态用地的分布更趋合理。该研究方法和结果可为区域城市规划和生态保护提供技术支撑和决策参考。

To solve the increasingly serious ecological and environmental problems during the urbanization process, reasonable determination of the land use structure and layout in future is the key. And study on land use scenario simulation under different constraints has been important to scientific planning and decision support. Based on the theory of landscape security patterns and GIS method, ecological security patterns were constructed to maintain the basic ecosystem services of Caofeidian new district which including flood regulation, freshwater supply, biodiversity protection and cultural services. And all these patterns were integrated into a comprehensive ecological security pattern with different security levels. The results indicate that the area of the comprehensive ecological security pattern was 1058.80km2, which accounted for about 53.53% of the study area. Among all levels of ecological security patterns, the area of baseline ecological security pattern that was also considered as the forbidden areas for construction was 312.67km2, accounted for about 15.81% of the study area. And the satisfied and ideal ecological security pattern was 308.15km2 and 437.98km2 respectively. Based on the remote sensing data and GIS method, a land use scenario simulation methodology was developed to integrate CA-MARKOV chain and ecological security pattern at a regional scale. Two scenarios were developed to compare the impact of our land use modeling approach. No ecological conservation scenario is a continuation of the current trends and involves only limited constraints on development. The ecological security pattern conservation scenario （ESP conservation scenario） incorporates ecological security pattern conservation network at different levels. The results indicate that under ESP conservation scenario, there is 74.07km2 newly increasing construction land within the range of overall ecological security patterns, while it is 91.54km2 less than no ecological conservation scenario. An increase of 17.47km2 indicates that the ecological security patterns were effectively protected under the ESP conservation scenario. Especially within the range of baseline ecological security pattern, the quantity of newly increasing construction land is 0 under ESP conservation scenario, while it is 31.07km2, indicating an entirely conservation of baseline ecological security pattern under ESP conservation scenario. Comparative analysis of each scenario with landscape metrics indicated that under the ESP conservation scenario, the number of urban patches increased, indicating that a slightly more fragmented landscape. The value of the Shannon’s Diversity Index （SHDI） for no ecological conservation scenario and ESP conservation scenario does not change because under both scenarios the number of classes remains the same, and there are no significant differences in the proportional distribution of the area covered by each land use class. The values of the Shannon’s Evenness Index （SHEI） are a slight increased under ESP scenario suggests that the landscape composition has become more even, indicating a transition from a dominant land cover class towards a more diversified landscape. PSCoV for cultivated land, water, beach and saltern changed little under both scenarios, but PSCoV for construction land was obviously increased under no ecological conservation scenario, suggests that under no ecological conservation scenario there are some consolidated urbanized areas in which some intra-urban open space are gradually built out, thus creating some larger urban patches and significant variability in patch size.