摘要：Biodiversity research in urban settings constitutes an interdisciplinary field combining boththe natural and human sciences. A full understanding of the patterns and processes underlying the dynamicof biodiversity in urban ecosystems needs to include humans in models of ecological functioning. We focuson the planting practices of gardeners to identify the bottom-up and top-down human influences on thefloral diversity of the Mediterranean gardens in an urbanizing rural zone. An initial ecological study ofcultivated flora in 120 private gardens showing floristic pattern variations along an urbanization gradientwas combined with a sociological survey. This survey aimed at collecting reasons for planting in gardensin connection with cultivated species. These reasons were classified into categories and analyzed accordingto the frequency of cultivated species within the entire gradient. Floristic heterogeneity in gardens,represented by the richness of uncommon species, is predominantly caused by social factors, particularlyrelated to the practices and social networks of gardeners who tend to diversify the range of species that areplanted. Floristic uniformity, defined by a high frequency of occurrence of plant species, results not onlyfrom social factors but also from natural factors that exert high pressure in the Mediterranean region. This"floristic norm" is also influenced by the urban context, which can modify the expression of natural andsocial factors and lead to differences in plant species compositions between housing density zones. Moregenerally, these results stress the importance of considering both individual choices and city-level influencesthrough an interdisciplinary approach to understanding the underlying processes that establish urbanbiodiversity patterns at a small scale
