摘要:被称为"钢筋水泥森林"的现代城市存在大量的墙体，包括建筑外墙、独立围墙、挡土墙等类型。通常情况下，这些完全硬质化的界面不会被认作为生境或栖息地。以典型山城重庆市为例，探索城区范围内墙体成为城市生境的可能性。于2017年9-11月对重庆主城区共120块墙，包含359个4×1 m小样方，调查墙面上自生植物的物种、覆盖度等信息；记录墙体4类特征共22个因子作为生境影响因素；并采用方差分解和典范对应分析（CCA）排序法研究影响因素与自生植物组成和分布的关系。结果表明：（1）市区墙境自生植物丰富，共记录到70科149属193种，以菊科植物种类最丰富，其次是禾本科和荨麻科。优势种包括蜈蚣草（蕨类）、井栏边草（蕨类）、构树幼苗（乔木）、贯众（蕨类）和黄葛树幼苗（乔木）。相比平面环境的自生植物以旱生为主，墙体上喜阴湿的蕨类植物占明显优势，反映出墙体作为生境的独特性，可以作为城市生态空间的有效补充。（2）墙体4类特征共解释自生植物组成与分布变化的14.4%，植物传播、定植与构建是一个综合复杂的过程，受各种随机因素影响；此外，本文所选因素也未考虑更大尺度的周边景观等因素。所有因子中，墙体高度、藤蔓覆盖度和墙体遮阴率是影响植物变化的主要因子，且与CCA排序第1轴相关性最强。这些因子均与墙体自身湿度有关，表明水分在决定墙面植物组成与分布起主要作用，植物在墙面沿水分呈梯度分布。讨论了本研究对现代城镇绿化的启示，从自然做功的角度提升城市生态系统服务，为城市生态设计与低成本管理提供科学依据。



Abstract:Cities are known as "concrete forests," and they have substantial walls of many types, including buildings, free-standing (boundary), and retaining (those used for reinforcing slopes or to confine river channels). Generally, these completely concrete walls are not considered as habitats. Using a typical mountainous city, Chongqing, as the case study, we aimed at exploring the possibility that urban walls can act as habitats in cities. From September to November 2017, we surveyed 120 walls, across 359 sampling quadrates, to obtain spontaneous vegetation data and associated wall characteristics. The effects of wall characteristics on the variation of spontaneous vegetation was calculated using variance partitioning and canonical correspondence analysis (CCA) ordination method. Vascular plants totaled 193 species in 149 genera from 70 families. The Compositae family had the greatest number of species and was followed by Gramineae and Urticaceae. The dominant species included Pteris vittata, Pteris multifida, seedlings of Broussonetia papyrifera, Cyrtomium fortune, and seedlings of Ficus virens. They occurred in more than 40% of all quadrates. The wall vegetation showed a diverse range of plant life-forms (i.e., woody, fern, and vine). Compared to xerophytes that dominate planar environments, more fern species inhabited the walls. This finding is consistent with that of other studies. This reflects the uniqueness of walls as habitats, and urban walls can act as a valuable complement to urban ecological spaces. The explanatory power of all four wall characteristics was low (14.4%). The spontaneous species assemblage was a complex process, and it was influenced by environmental stochasticity. Additionally, the unexplained portion may come from the influence of the large-scale landscape context. Among all the variables, wall height, vine coverage, and wall shade were the most important factors that influenced vegetation composition and distribution, and they had the highest correlation with the first constrained axis of the CCA ordination. All variables were relevant to wall humidity. This indicates that moisture plays a decisive role in structuring vegetation on urban walls. Lastly, we discussed the implications of this study on greening and landscaping contemporary cities. Urban biodiversity improvement can be done by "allowing nature to work". Our study also provides scientific support for urban ecological design and low-cost management.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201804130848