城市绿地干旱生境的园林树种选择机制研究

Drought is a widely recognized research topic within the academic circles. The landscape trees will be exposed to severe drought habitat stresses, due to the uneven precipitation in time and space, water circulation changing and underlying surface feature transformation by climatic change, urbanization and artificialization respectively. Thus, the ecosystem stability of urban green space confronts increasingly severe challenges. Developing effective and sustainable adaptation strategies for the ecosystem security of urban green space should involve the establishment of evaluation and selection system for drought-resistant tree species, discovering classification features of drought habitats, selecting appropriate and anticipatory species that have adapted to local habitats. This study focuses on drought tolerance of tree species, classification of the drought habitats, and landscape tree species selection. Through analysis of morphological features, survey of ecological habits, and determination of physiological properties, the multi-variable evaluation and ranking system will be developed. Meanwhile, quadrat survey and cluster analysis are adopted for the classification of urban drought habitats. Drought Habitat-Specie-Matrix (DHSM) and Climate Envelope Models will be used for the accurate selection of tree species in order to enhance resilience and comprehensive functions of landscape ecosystems.

干旱是一个全球学术界广泛关注的课题。由于气候变化加剧了降水的时空分布不均，城市化进程阻隔了水分循环过程，人工化设施改变了下垫面的性质，使园林树种的立地生境受到了不同的干旱胁迫影响，城市绿地生态系统的稳定性面临日益严重的挑战。为了维持城市绿地的生态安全，构建抗旱树种的评价选择体系，探索干旱生境的分类依据，因地制宜的选择树种是园林可持续发展的有效对策。该研究以树种干旱适应性，城市干旱生境立地类型划分和园林树种选择为核心，通过对树种形态学特征分析、生态习性调查和生理指标测定，构建多指标评价体系对园林树种排序分级；运用样方调查和聚类分析方法，划分城市干旱立地的生境类型；借助干旱生境-物种矩阵、气候阈值模型等对城市干旱立地进行精确化树种选择。以此提升园林绿地系统的生态弹性和综合功能。

全球范围内的气候变化加大了城市水资源压力，城市化进程的推进则进一步加剧城市局地立地困难程度。以优化城市绿地生态功能和改善人居环境品质为目的，探讨优质的抗旱园林树种资源以及应对气候变化的抗性树种规划策略，具有重要的理论意义和实践价值。本研究以园林树种的干旱适应性为核心，基于风景园林的视角，关注于城市园林绿地复杂生境条件的干旱问题。主要研究内容如下：根据近年来的气象资料，概括了干旱热点区域近的气候变化特征与趋势；通过野外样地调查，形态学特征分析和干旱模拟实验，掌握了树种在干旱条件下的生态习性，生物学特性和生理响应策略；设计不同的城市绿地常用渗透性铺装材料，比较园林树种在模拟道路环境中的干旱适应性；最后，构建了基于干旱适应性的多指标园林树种评估体系与选择方法。科学全面的研究抗旱性需要结合宏观、中观乃至微观多个层次结果的互相修正，以实现节约、高效与健康的城市生态系统构建。研究成果以期为未来城市干旱生境的树种选择和规划提供理论依据和实践指导。