Characteristics of residential backyards that contribute to conservation and diversity of urban birds: a case study in a Southeastern Brazilian city

Abstract

The structure of bird communities living in cities may have different characteristics depending on the magnitude of building versus green area. In this study, we evaluated the contribution of residential backyards to the diversity of urban birds in the city of Jacareí, São Paulo, Brazil. We hypothesized that the composition and structure of bird communities would change according to (1) backyard, (2) neighborhood characteristics, (3) seasonality, and (4) bird species. Backyard characteristics assessed include area, vegetation structure (number of plant species), tree mean height, number of trees, percent of impervious surfaces, and presence of pets, such as dogs and cats. In a 400 m radius buffer around each backyard we measured the number and total area of green spaces, number of neighborhood trees, and nearest backyard distance. Surveys were performed during the non-breeding period (summer, autumn, and winter). Backyard area, pet presence, and number of trees in the neighborhood in which the backyard is located were positively correlated with bird richness. In turn, abundance was more strongly influenced by the period of visit, number of shrubs above 2 m tall, and nearest backyard distance. Our results showed that the backyards that present characteristics such as largest area, tallest trees and shrubs and that are close to isolated trees and other green areas increase the possibilities of species, especially native species, to remain in urban areas. Therefore, this study expands our knowledge of the effect of urbanization on avian diversity in a typical Latin American city inserted in the Atlantic Forest biome and shows the importance of private green areas to the composition of the landscape and conservation of urban biodiversity.