Do cities act as environmental filters for butterflies? Spatiotemporal patterns of distribution, functional traits and phylogeny of butterflies in urban gradients

Abstract

Urbanization and land use transformation are a key driver of global biodiversity loss, especially in terrestrial ecosystems. Studies on the impact of urbanization on butterflies are still ambiguous, preventing general conclusions about the impact on this group. This thesis integrates multiple ecological approaches to the spatio-temporal, functional, and phylogenetic patterns in butterfly communities in response to urbanization gradients. In the first chapter, we present a systematic review and meta-analysis to evaluate the global effects of urbanization on butterfly communities and the factors that influence the patterns found. In total, we evaluated 1,227 studies in order to globally generalize responses of butterfly species richness, abundance, and diversity in response to urbanization. We found a negative effect of urbanization on butterfly richness and abundance, although it did not affect species diversity. There has been an increasing increase in studies related to this topic in recent decades, but with studies predominantly developed in temperate regions. In tropical regions, the effect of urbanization on butterfly richness is stronger, despite the number of studies being smaller. We suggest the urgency in discussing the consequences of urbanization at different scales and climatic zones to expand knowledge and decision-making involving the impacts of urbanization on butterflies in cities. In the second chapter, we investigate how the taxonomic, functional, and phylogenetic diversity components of the butterfly community are influenced spatiotemporally along urbanization gradients. We sampled a total of 1,451 butterflies, from 116 species distributed in six families along urbanization gradients. Thirteen functional traits were measured and analyzed, considering phylogeny in species distribution and community composition. We observed lower richness and abundance of butterflies in urban areas, both in space and time, and communities structured by species turnover. All functional traits evaluated showed a moderately high phylogenetic signal, but we observed that the relationships between functional traits and the urban gradient occur independently of the phylogenetic relationship of the species, except for the thorax length trait, which showed greater length in preserved and urban areas. This occurrence can be explained by specific responses and variations in each species, related to adaptations of some urban species to face challenges or explore unique opportunities in these environments. We suggest that the urban gradient acts as an environmental filter, potentially randomly selecting species adapted to the urban environment, and that factors such as conditions and resources unevenly distributed in cities can separate species and select adapted, but distant, lineages to compose local communities. The results found in this study can be useful to support and guide conservation efforts in urban habitats contribute to decision-making by urban design professionals and expand knowledge about the importance of urban green spaces as important providers of ecosystem services if managed appropriately.