Abstract

Spontaneous plant communities found in abandoned post-industrial landscapes develop in unique conditions which can create novel community assemblages. We examined changes in plant community composition and its relation to soil properties in an urban brownfield more than 40 years following site abandonment to better understand the community’s long-term trajectory. A former railyard and industrial area built on fill material, the study site includes four primary habitat types: grasslands, perennial forb assemblages, shrubland, and early successional forest. Plant species cover was measured in permanent plots in 2008 and 2016/17. In 2008, soil samples were collected and analyzed for a suite of properties. Species richness and Shannon diversity increased across the site from 2008 to 2016 (40 and 48 years post-abandonment) though increases in these parameters were highest in plots with lower metal concentrations. Evenness changed little in this time period. Percent cover of woody species increased in grassland and forb plots while percent cover of vines increased across all habitat types. Forb species tended to be associated with higher nutrient concentrations while woody species distribution was correlated with higher concentrations of heavy metals. The mitigation of soil stress, limitations in propagule availability, and loss of tree canopy cover following disturbances may have all played a role in influencing increases in diversity in this time period. Considering difficulties in comparing post-industrial abandoned landscapes to other anthropogenic and natural habitats, long-term study is needed to refine our understanding of community assembly in urban brownfields and better guide management practices.

摘要

在废弃的后工业景观中发现的自发植物群落在独特的条件下发展，可以创造出新颖的群落组合。为了更好地了解社区的长期发展轨迹，我们在废弃场地后的40多年中研究了城市棕地植物群落组成的变化及其与土壤特性的关系。该研究场所以前是一个用填充材料建造的铁路场和工业区，包括四种主要的栖息地类型：草地，多年生福布斯组合，灌木丛和早期演替森林。在2008年和2016/17年的永久样地中测量了植物物种的覆盖率。在2008年，对土壤样品进行了收集并进行了一系列性能分析。从2008年到2016年（废弃后40年和48年），整个站点的物种丰富度和香农多样性有所增加，尽管这些参数的增加在金属浓度较低的样地中最高。在这段时间内，均匀度变化不大。在所有生境类型中，草地和禁牧区的木本物种覆盖率增加，而藤本植物的覆盖率增加。福布斯物种往往与更高的养分含量相关，而木本物种分布与更高浓度的重金属相关。在此期间，减轻土壤压力，限制繁殖繁殖能力以及扰乱后树木冠层覆盖率的丧失可能都在影响这一时期多样性的增加中发挥了作用。