南京典型城市道路植物多样性与土壤因子的耦合关系

目的 植物-土壤系统的作用机制复杂,揭示城市道路绿地植物群落正向演替的限制因子,筛选配置最优的植物群落类型,为城市道路绿化景观再设计提供数据支撑,也为城市道路绿化带土壤管护提供理论指导。方法 以南京市大气污染程度排名前列的3条城市道路(江北大道、诚信大道和仙林大道)为研究对象,选取典型的植物群落进行实地勘察和土壤采样分析,根据植物的生活型划分群落类别(单层群落、双层群落、3层群落和4层群落),采用灰色关联度分析方法测算不同类型群落的物种多样性与土壤因子的耦合关系。结果 随群落层次结构的增加,城市道路绿地的植物群落物种多样性水平呈现升高趋势。4层群落的土壤含水率普遍较高;土壤有机质、土壤全氮和土壤速效钾的含量随群落层次的增加呈现增大趋势。土壤因子更易影响植物的分布,而对植物种类的影响最小;土壤全钾、土壤容重、土壤有机质、土壤全氮、土壤全磷和土壤pH是植物生长的主要限制因子,平均关联系数均大于0.90,与物种多样性的关联度极强。随群落层次结构的增加,物种多样性与土壤因子的耦合度增大。结论 结构层次丰富的植物群落,其生态系统稳定性强,因此,城市道路绿化景观建设中,在考虑环境条件和交通需求的基础之上,植物群落的构建应首先推荐结构丰富的4层群落。

Modeling the degree of coupling relationship between plant community diversity and soil properties on typical urban roads in Nanjing

【Objective】 The plant-soil system has a complex mechanism of action. We aimed to reveal the limiting factors for the positive succession of plant communities on urban roads as well as screen for the best plant community types. We expect the results of this study to provide a theoretical guidance for soil management and protection, and provide data supports for redesigning urban road green landscapes. 【Method】 Three urban roads (Jiangbei Avenue, Honesty Avenue and Xianlin Avenue) that ranked high in the air pollution level in Nanjing, China, were regarded as research objects. Typical plant communities were selected for field surveys and the soil sampling analysis. According to the lifestyle of the plant, the community was divided into the following categories: single-layer, double-layer, three-layer and four-layer communities. The degree of coupling and interaction between plant community diversity and soil properties were measured using the gray correlation model. 【Result】 With the increase in community hierarchy, the level of species diversity showed an upward trend. The four-layer community had the highest soil water content, and the contents of soil organic matter, soil total nitrogen and soil available potassium showed an increasing trend with an increase in the community level. Soil properties were more likely to affect the uniformity of plant distributions than plant species, which experienced a minimal impact. Soil total potassium, soil bulk density, soil organic matter, soil total nitrogen, soil total phosphorus and soil pH were the main limiting factors for the vegetation growth. The correlation with plant factors was greater than 0.90 (a strong correlation). With the increase in community hierarchy, the degree of coupling of the plant-soil system increased. 【Conclusion】 Plant communities with high structural levels have a strong ecosystem stability. Considering environmental conditions and transportation needs, the recommendation for urban road greening is a four-layer community with a rich community structure.