基于生态功能多尺度权衡的长三角地区森林景观格局优化研究

With the deepening development and continuous expansion of the economic circle of Yangtze River Delta, the contradiction between urban development and environmental resources is becoming increasingly prominent. The natural landscape represented by forest, as the provider of resources and the regulator of environment, has not yet attracted enough attention. Based on the strategic background of "beautiful Chinese Construction Demonstration Area", forest landscape in hilly area of the Yangtze River Delta has been taken as the research object in this project. The ecological function evaluation on multi-scale, as the main line, aims to build a multi-dimensional evaluation index system of ecological function with regional characteristics. Ultimately, a set of pattern optimization scheme, which is suitable for forest landscape in hilly area of the Yangtze River Delta will be integrated. The sampling survey, remote sensing technology and GIS spatial analysis method will be applied to evaluate and weigh the forest ecosystem function on different scales. The redundancy analysis and generalized additive model will be used to screen the key influence factors of the ecological function on each scale further. In addition, the association between landscape pattern and key ecological function and their feedback mechanism will be constructed. Combined with the minimum cumulative cost resistance model, key areas of the ecological source, corridor, and key nodes in ecological process will be recognized. The purpose of the project is to promote the function of forest ecosystem in Yangtze River Delta region to maximize. It also aims to meet the needs of urban sustainable development, and provide theoretical and technical support for the study of landscape pattern optimization.

随着长三角经济圈的深化发展与持续扩容，城市发展与环境资源之间的矛盾日趋凸显，以森林为代表的自然景观作为资源的供给者和环境的调节者，尚未引起足够的重视。基于“美丽中国建设示范区”的战略背景，本项目拟以长三角低山丘陵区森林景观为研究对象，以多尺度生态功能评价为主线，构建具有区域特性的多维度生态功能评价指标体系，集成一套适宜长三角低山丘陵区森林景观格局优化配置方案。本项目采用样地调查、遥感技术和GIS空间分析方法评价并权衡不同尺度下森林生态系统功能；借助冗余分析、广义相加模型筛选各尺度下生态功能的关键影响因素，构建景观格局与关键生态功能之间的关联与反馈机制；结合最小累积耗费阻力模型识别生态源、廊道和关键节点等生态过程关键区，以促进长三角地区森林景观生态系统功能最大发挥，满足该地区城市可持续发展的需要，并为景观格局优化研究提供理论和技术支撑。

随着长江三角洲区域一体化的深化发展，城市化过程与自然资源之间的矛盾日益凸显，以森林为代表的自然景观作为资源的供给者和环境的调节者，其景观结构与生态功能之间多尺度作用机理尚不明确。在“美丽中国建设示范区”的战略背景下，本项目以长三角低山丘陵区森林景观为研究对象，以多尺度生态功能评价为主线，集成一套适宜长三角低山丘陵区森林景观格局优化配置方案。通过对典型研究区的调查与分析，结果显示：1）在斑块尺度上，茅山地区不同植被类型下表征土壤固碳和养分功能的土壤有机碳（SOC）和全氮（TN）含量差异显著，阔叶混交林SOC和TN储量最高（208.6 Mg ha-1和20.1Mg ha-1），分别比灌木林和马尾松林高88.4%和148.7%；随着土层加深，环境因子对SOC和TN含量的解释率从62.7%降低到54.7%。土壤容重、NDVI植被指数、pH是影响SOC和TN储量的主要因素，阔叶混交林固碳潜力较优。综合生态系统功能与质量评估方面，基于安徽丫山国有林场森林资源的二类调查数据，从生产力、森林结构、抵抗力和土壤状况等方面构建出了一套适合森林质量与生态功能评价的指标体系；基于遗传算法优化的BP神经网络模型为科学地评价森林的质量和功能提供新的方法，单一马尾松人工林林分生产力与稳定性弱。2）景观尺度上，在山地丘陵的坡面层次，SOC和TN具有明显的空间自相关性，SOC和TN的结构方差分别为60.8%-81.7%，和50.1%-60.6%，主要影响因子为地表凋落物物质量和坡度等。地理加权回归GWR模型模拟土壤有机碳和全氮与环境因子之间的回归关系GWRTN （R2=0.56）要优于全局回归模型OLSTN（R2=0.49）,GWRSOC(R2=0.53)高于OLSSOC (R2=0.49)。在权衡关系方面，林地水源涵养量与碳储量、生境质量之间具有一定的权衡关系。茅山景观格局中共有重点建设的 212个生态节点，而丫山仅有3个生态节点，分布于建设用地、耕地和林地景观中。丫山森林景观生态廊道连通性相比茅山好，便于生物生态流的流通。生态节点和廊道的识别，为保障源地和各景观组分生态流的畅通，优化景观格局，进而解决景观破碎化、生态功能退化问题提供了科学依据。