Street design in suburban areas and its impact on bird communities: considering different diversity facets over the year

Abstract

Several studies have shown that suburban areas have higher bird diversity than non-urban areas. Native vegetation cover, habitat complexity and socioeconomic variables of suburban areas have shown to influence bird richness and composition. However, few studies have explored the effect of street design on bird communities by analyzing different facets of diversity, such as taxonomic, functional and phylogenetic diversity. Moreover, few studies have explored bird-habitat relationships during an annual cycle. In this study, we analyzed total and native bird community differences between two street designs in a suburban area of Mar del Plata city (Argentina) during the breeding and non-breeding seasons. We surveyed streets and chicanes (street with a zigzag pattern), the latter being characterized by a smaller paved area and larger lawn cover than the former. Birds were counted along 100 × 50-m transects. Total bird taxonomic and functional diversity were higher in chicanes than in streets during both seasons, whereas bird richness was higher in chicanes than in streets during the non-breeding season. Native bird richness was higher in chicanes during both seasons, whereas native species diversity was higher in chicanes than in streets during the non-breeding season. Total and native evolutionary distinctiveness and native functional diversity did not vary between street designs or seasons. Total and native species composition were similar between street designs and seasons, but the Eared Dove (Zenaida auriculata), the Rufous Hornero (Furnarius rufus), the Chalk-browed Mockingbird (Mimus saturninus) and the Shiny Cowbird (Molothrus bonariensis) showed increased abundances in chicanes. The results suggest the importance of reducing paved road areas, with the consequent increase of vegetated areas and, therefore, of bird diversity in suburban areas. Our analysis highlights the need to conduct studies during an annual cycle for a better understanding of bird community dynamics in urban environments.