Street trees reduce the negative effects of urbanization on birds

PLoS One. 2017 Mar 23;12(3):e0174484. doi: 10.1371/journal.pone.0174484. eCollection 2017.

Abstract

The effects of streets on biodiversity is an important aspect of urban ecology, but it has been neglected worldwide. Several vegetation attributes (e.g. street tree density and diversity) have important effects on biodiversity and ecological processes. In this study, we evaluated the influences of urban vegetation-represented by characteristics of street trees (canopy size, proportion of native tree species and tree species richness)-and characteristics of the landscape (distance to parks and vegetation quantity), and human impacts (human population size and exposure to noise) on taxonomic data and functional diversity indices of the bird community inhabiting streets. The study area was the southern region of Belo Horizonte (Minas Gerais, Brazil), a largely urbanized city in the understudied Neotropical region. Bird data were collected on 60 point count locations distributed across the streets of the landscape. We used a series of competing GLM models (using Akaike's information criterion for small sample sizes) to assess the relative contribution of the different sets of variables to explain the observed patterns. Seventy-three bird species were observed exploiting the streets: native species were the most abundant and frequent throughout this landscape. The bird community's functional richness and Rao's Quadratic Entropy presented values lower than 0.5. Therefore, this landscape was favoring few functional traits. Exposure to noise was the most limiting factor for this bird community. However, the average size of arboreal patches and, especially the characteristics of street trees, were able to reduce the negative effects of noise on the bird community. These results show the importance of adequately planning the urban afforestation process: increasing tree species richness, preserving large trees and planting more native trees species in the streets are management practices that will increase bird species richness, abundance and community functional aspects and consequently improve human wellbeing and quality of life.

MeSH terms

  • Animals
  • Biodiversity
  • Birds*
  • Brazil
  • Conservation of Natural Resources / methods*
  • Ecosystem
  • Humans
  • Quality of Life
  • Trees*
  • Urbanization*

Grants and funding

This work was supported by Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (http://www.cnpq.br/) [MCR (grant number 312045/2013-1) and MR]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (http://www.capes.gov.br/) (JCCP and FM); Fundação de Amparo à Pesquisa do Estado de São Paulo, grant number 2013/50421-2 (http://www. fapesp.br/) (MCR); and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (http://www.fapemig.br/) (MR). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.