Exploring relationships: Railway Ecology and Black locust

Urban environments, heavily influenced by human activities, often exhibit increased levels of plant invasion. This is driven by disturbances and the influx of non-native species. Utilizing these invasive species for ecological restoration, particularly in polluted, early-stage ecological sites, offers a novel approach to environmental management. Railways in urban areas, subjected to various human-induced stresses such as vegetation management and pollution, are ideal setting for studying these dynamics. Black locust (Robinia pseudoacacia L.), an invasive non-native tree species in Europe, is commonly found along railway tracks, either planted for stabilizing embankments or through spontaneous expansion. Our study focuses on black locust's role along electrified railways in the north-eastern Po plain by examining the structural characteristics of black locust stands in relation to soil pollution levels. We surveyed 42 railway sites, each characterized by varying traffic and functional purposes. These sites were defined as 10 m units along the railway track, with the width determined by the tree canopy's extent. Within each sampling unit, we collected data on general vegetation attributes, tree dimensions, and understory species. Soil and black locust leaf samples were analysed for heavy metal content using ICP-OES. Our findings show varying levels of heavy metals in the soil at these sites, with the intensity of rail traffic significantly influencing their concentration. Copper levels consistently surpassed the regulatory limits for industrial areas, and concentrations of nickel, lead, zinc, and tin exceeded thresholds for green spaces. Initial assessments suggest that black locust trees are resilient to soil contamination, supporting previous research on the species' tolerance to polluted environments. Further research is required to fully understand the impact of black locust on local ecosystems, especially in comparison to native species.