Local and landscape effects on ant functional and taxonomic compositions across green spaces of a tropical metropolis

Urbanization is one of the main processes driving environmental transformation, altering the structure and functioning of biological communities across multiple spatial scales. In this study, we evaluated the effects of local and landscape variables on the taxonomic and functional composition of ants in different types of urban green spaces in the city of Salvador, Brazil. A total of 62 sampling points were surveyed across forest fragments, squares, streets medians, and vacant lots, using specific methods for both ground-dwelling and arboreal strata. We recorded 93 ant species distributed among 20 functional groups. Our results indicated that, at the local scale, leaf litter depth was the primary explanatory factor for both taxonomic and functional richness, as well as for functional composition. At the landscape scale, human population density and vegetation cover surrounding the sampling points influenced the distribution of species and functional groups, revealing contrasting patterns between specialist and generalist species. While arboreal, hypogeic, and fungivorous ants were more dependent on structurally complex and conserved habitats, epigeic, omnivorous, and some predatory species were favored in more simplified and heterogeneous environments. These findings highlight that biodiversity conservation in urban areas depends on integrated strategies across multiple scales, encompassing management practices that ensure local structural complexity alongside planning that promotes habitat heterogeneity at the landscape level. Overall, the study demonstrates that the arrangement and quality of urban green spaces play a central role in maintaining both taxonomic and functional diversity of ant communities in tropical cities.