Do cities export biodiversity? Traffic as dispersal vector across urban–rural gradients

摘要: Urban areas are among the land use types with highes richness in plant species. A main feature of urban floras is high proportion non-native species often divergent distribution patterns along urban-rural gradients. impacts on usually associated increasing human activity rural-to-urban As an important stimulus diversity, human-mediated seed dispersal may drive process similarity between and rural by moving across We used long motorway tunnels as sampling sites for propagules that released vehicles to test impact traffic gradient. Opposite lanes separated solid walls, allowing us differentiate deposition into vs. out city. Both magnitude samples from two were higher leading city, indicating 'export' biodiversity traffic. proportions seeds also outbound lanes, foster invasion processes starting cities surrounding landscapes. Indicator analysis revealed only a few confined while mostly habitats significantly lanes. The findings demonstrate reflects different sources directions, thus exchange