Species diversity of urban biota: The role of habitat type and biogeography

The rapid development of urban areas triggers a series of ecological changes in the landscape structure that have important consequences for biodiversity. Urban habitats provide an environment for various biological organisms and their communities, but how the effects of habitat types interact with biogeography to control species diversity in urban areas is still poorly understood for many taxonomic groups. The study aimed to elucidate the species diversity response of vascular plants and terrestrial gastropods to urban habitats in a multi-city assessment of two Central European biogeographical regions (Pannonian and Carpathian). Species diversity (alpha, beta and gamma) was calculated based on plant and gastropod records sampled in 30 Slovak cities within six and three habitat types, respectively. Linear mixed-effects models showed that the importance of both predictors depended on the taxonomic group. The high local and regional plant diversity found in cemeteries and floodplains was accompanied by a peak of gastropod alpha diversity in the Carpathian floodplains. These results suggest that dynamic and well-structured habitats with a mosaic of patches should be included in urban planning, as their high biodiversity values may contribute to the resilience of urban ecosystems to future environmental changes. We also found that climatic constraints reduced alien plant diversity in Carpathian habitats, while the species-reducing effect of environmental filtering and dispersal limitations played a prominent role in the plant diversity patterns of city centres. The present differences in species diversity caused by the interplay of climate and human impacts also highlight the need for a region-specific approach to managing urban biodiversity.