Concrete Jungle: habitat heterogeneity acts as environmental filter on multidimensional diversity of fruit-feeding butterflies in urban Savannahs of Cerrado biome

Urban environments exert many pressures on biodiversity, which is especially concerning in the tropics given their high biodiversity and rapid land-use change. Urbanization may result in the formation of new ecological environments, generally more homogeneous and less diverse species assemblages. A key open question is whether phenotypic shifts driven by urbanization are mediated by ecological plasticity, or if evolutionary changes are also determinant. In this context, we surveyed along an urbanization gradient, to test their effects on multidimensional diversity of fruit-feeding butterfly assemblages in the Cerrado biome. We tested if more urbanized areas, exhibiting less diverse and more homogeneous vegetation, would host more simplified butterfly assemblages, mainly composed of large-bodied, desiccation-resistant, and dietary generalist species. We observed lower abundance but higher taxonomic and functional diversity from conserved to urban savannahs. Phylogenetic diversity was positively associated with plant density, regardless of urban influence. Changes in species composition translated into distinct functional but not phylogenetic composition along the urban gradient. Urbanized savannahs were dominated by small-bodied species with narrower thorax widths, limited flight capacity and generalized diets, while conserved savannahs were characterized by large-bodied, iridescent, and eyespotted species. Camouflaged species prevailed in more sparsely vegetated urbanized savannahs. Beyond the role of greenspaces in supporting butterfly diversity, this study demonstrates that native vegetation cover and habitat heterogeneity further enhance diversity and should be integrated into urban planning. These factors not only facilitate butterfly dispersal and gene flow across the city but will also promote recolonizations which prevent local extinctions in isolated urban green spaces, thus resulting in more biodiverse cities.