Peri-urban plant communities perform key ecological functions. However, the integrity of peri-urban vegetation is threatened by the continuous expansion of built-up areas and anthropogenic activities, which result in low-intensity, but continuous and pervasive chronic anthropogenic disturbances (CADs). Despite the growing attention to the ecological role of peri-urban vegetation patches, the assessment of the relationship between CADs and typical Mediterranean plant communities at the local scale is still lacking. In this work, both the compositional and functional responses to typical CADs of five vegetation types were assessed in 48 plots, located around the city of Genoa (Italy). The main anthropogenic and environmental drivers of species composition were identified through a Non-Metric Multidimensional Scaling, and selected variables were used to fit a partial Redundancy Analysis. Differences in the number of alien species in relation to total CAD intensity were assessed with a Kruskal-Wallis test. Regarding functional composition, the community weighted mean values (CWMs) of five functional traits were computed for each plot. Generalized linear models were then fitted to assess the relationship between the CWMs and CADs intensity. Our results showed that the specific composition of peri-urban plant communities of Genoa is shaped by interacting environmental and anthropogenic factors. Considering composition, CADs promote the increase of alien species’ number. Moreover, the increased intensity of CADs altered the functional composition, with increasing specific leaf area, leaf nitrogen content and seed bank longevity. Overall, the effect of typical Mediterranean CADs is more pronounced on the functional composition than on the taxonomic composition of peri-urban plant communities. This work highlights the relevance at the local scale of the typical CADs of the Mediterranean area in influencing the different vegetation types that characterise a peri-urban zone.

中文翻译：

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城郊地中海植物群落受到长期人为干扰的影响

城郊植物群落发挥着关键的生态功能。然而，城市周边植被的完整性受到建成区不断扩张和人类活动的威胁，导致低强度但持续和普遍的慢性人为干扰（CAD）。尽管人们越来越关注城郊植被斑块的生态作用，但对局部尺度的 CAD 与典型地中海植物群落之间关系的评估仍然缺乏。在这项工作中，在位于意大利热那亚市周围的 48 个地块中评估了五种植被类型对典型 CAD 的组成和功能响应。通过非度量多维尺度确定了物种组成的主要人为和环境驱动因素，并使用选定的变量来拟合部分冗余分析。通过 Kruskal-Wallis 检验评估外来物种数量与 CAD 总强度之间的差异。关于功能组成，计算了每个样地五个功能性状的群落加权平均值（CWM）。然后拟合广义线性模型来评估 CWM 和 CAD 强度之间的关系。我们的结果表明，热那亚城郊植物群落的具体组成是由环境和人为因素相互作用形成的。从组成上看，CAD促进了外来物种数量的增加。此外，CAD强度的增加改变了功能组成，增加了比叶面积、叶氮含量和种子库寿命。总体而言，典型的地中海 CAD 对城郊植物群落功能组成的影响比对分类组成的影响更为明显。这项工作强调了地中海地区典型 CAD 在当地尺度上对影响城郊地区不同植被类型的相关性。