Exploring floristic patterns across urban habitats: a case study of the city of Sarajevo (Balkan Peninsula)

This study aimed to analyze differences in species composition and richness, investigate the scope of anthropogenic changes of the flora, and determine diagnostic species in urban habitat types in the city of Sarajevo. A total of 872 taxa were recorded in 884 sites across 16 anthropogenic and semi-natural habitat types, indicating a diverse range of plant species present in the urban environment. The PERMANOVA analysis indicated statistically significant differences between habitat types in regard to qualitative species composition, and the SIMPER analysis determined a list of plant species contributing the most to distinguishing the urban habitat types. Anthropogenic habitats generally had fewer species compared to semi-natural ones. Homegardens were an exception, characterized by large floristic richness, due to their complex structure and position within the urban area. Semi-natural habitats harbored more diagnostic species (phi coefficient > 20) compared to anthropogenic ones, indicating their unique ecological conditions. Species composition similarity was highest for habitats subjected to erosion and railways, while forest remnants and shrubbery showed the lowest similarity due to geographical dispersion and varying anthropogenic impact. The Kruskal-Wallis H and the Dunn’s test revealed a smaller proportion of alien, invasive, thermophilic and polyhemerobic species in semi-natural habitats compared to anthropogenic ones, reflecting the lower degree of human disturbance and alteration in these habitats. Hemicryptophytes were the most numerous life form in all urban habitats. The proportion of therophytes was nearly twice as high in anthropogenic habitats compared to semi-natural ones, suggesting greater stability and reduced anthropogenic impact in semi-natural habitats, which allows the supports the development of species with other life forms. Roadsides and homegardens were identified as hotspots for alien species. Overall, the study provides insight to the complexity of urban ecosystems, highlighting the differences in species composition and richness influenced by anthropogenic pressure.