How urbanization affects multiple dimensions of biodiversity in tropical butterfly assemblages

Abstract

We evaluated how the taxonomic, phylogenetic and functional diversities of butterflies and their community-weighted traits are affected by urbanization in the southeastern Brazilian Atlantic Forest. For this purpose, a dataset of Nymphalidae species distributed across 15 urban, semiurban, and rural fragments was analyzed. Urbanization was defined by a set of environmental variables. Furthermore, the total area of each fragment was also considered in the analyses but did not influence the results, in which disturbance level and patch connectivity drove the environmental variation across the urban matrix. Species diversity increased towards the more connected fragments, while phylogenetic and functional diversity did not vary in relation to urbanization. A high forewing:hindwing ratio and the frequency of tiger-like wings were positively related to the urban fragments, while a low forewing:hindwing ratio and iridescent wings were related to the semiurban and rural fragments. The suitability of highly interconnected rural habitats for the maintenance of butterfly diversity was corroborated as expected. Nonetheless, our results also showed that semiurban fragments preserved the ecologically relevant traits of butterflies related to forested habitats, expressed in butterfly groups possibly linked with dispersal capability to avoid predation. Careful management of semiurban fragments and urban landscaping, including highly structured and native vegetation outside urban parks, may increase the functional and taxonomic diversities or at least maintain the current levels of functionality in the urban matrix. Thus, it is possible to preserve the biological diversity of native fauna and flora and recover relevant ecosystem services, ensuring the conservation of Neotropical urban centers.