The effects of forest-savanna-grassland gradients on bird communities of Chiquitano Dry Forests domain, in western Brazil.

MAURICIO N. GODOI,EDIVALDO O. DE SOUZA

doi:10.1590/0001-3765201620150615

MAURICIO N. GODOI, EDIVALDO O. DE SOUZA

Open Access

https://doi.org/10.1590/0001-3765201620150615

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Abstract

Different vegetation types are distributed in mountains according to altitude, topography and soil. The composition and structure of bird communities in these areas can change in relation to the vegetation gradient, with particular communities occupying each habitat type. In this study we present the changes in composition, species richness and bird abundance over the gradient of forests, savannas and altitudinal grasslands of Maciço do Urucum, a mountainous region located in the Chiquitano Dry Forests domain in western Brazil. We recorded 165 bird species through qualitative and quantitative methods. Forested savannas, riparian forests and submontane forests presented the highest richness and abundance of birds, while arboreal savannas and altitudinal grasslands had intermediate and low values, respectively. The bird composition was similar between riparian and submontane forests, while other vegetation types present more dissimilar bird communities. Our results show differences in composition, richness and bird abundance among the vegetation types present at Maciço do Urucum, and highlight an important function of vegetation gradients for the conservation of bird communities in mountains. Additionally, this is the first study of the bird communities in the Brazilian Chiquitano Dry Forests, an important domain in the west of Brazil which has been poorly studied.

Highlights

In landscapes formed by vegetation gradients, bird community composition can be affected by the presence and distribution of different vegetation types (Skowno and Bond 2003, Jankowski et al 2012)
Considering only quantitative data obtained in point counts, the 11 most abundant species in the study area corresponded to 51% of total bird abundance, while 49% of bird abundance was divided between the 99 remaining species, with 21 species being recorded just once
These results show that the sampling effort and the point count method were suitable for sampling the majority of local bird species richness

Summary

Introduction

In landscapes formed by vegetation gradients, bird community composition can be affected by the presence and distribution of different vegetation types (Skowno and Bond 2003, Jankowski et al 2012). This pattern is due to the fact that many bird species are exclusive to certain habitats or are. DE SOUZA topography and soil (Navarro 1992, Blake and Loiselle 2000) In these regions, the diversity and composition of bird communities could present spatial variations in relation to the presence and distribution of different vegetation types (Navarro 1992, Blake and Loiselle 2000, Melo-Júnior et al 2001, Mallet-Rodrigues et al 2010). In the Serra da Bodoquena and Serra de Maracaju inventories of bird species showed high species richness, which could be partially explained by habitat diversity in these regions (Pivatto et al 2006, Nunes et al 2013)

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