Nonrandom filtering effect on birds: species and guilds response to urbanization.

Carmen Paz Silva,Olga Barbosa,Roger D. Sepúlveda

doi:10.1002/ece3.2144

Abstract

Using bird survey data taken in three cities in Southern Chile, we evaluated the hypothesis that changes in community composition from periurban to urban areas are not random. Furthermore, the consistency of species and guild loss was assessed across cities. A consistent pattern of difference in community and guild structure between urban and periurban habitats was found. In addition, a nonrandom loss of species was found in urban areas compared to periurban areas, and non‐native species dominated urban communities in all cities. The average abundance of omnivores, granivores, and habitat generalists was higher in urban areas, while insectivores and open habitat species were more abundant in periurban areas. These results strongly suggest that urban habitats act as filters offering suitable conditions for only a fraction of the bird species present in a given area, and the lack of suitable conditions may be facilitating local biotic homogenization in the three studied cities. The results of this study not only fill a biogeographical knowledge gap, but the work presented here also aids the general understanding of factors that affect community structure in habitats with varied levels of local and global urbanization.

Highlights

Urbanization, understood as the transition of undeveloped land to built-up or sealed areas (Berland 2012), is proceeding at a fast rate in many parts of the world and notably so in developing countries (United Nations 2014)
Species were present in all the sample sites, three were present exclusively in urban sites, and were only found in periurban areas
Forest specialist species such as Chucao and Magellanic Tapaculo and open habitat species such as Fire-eyed Diucon and Patagonian Sierra-finch were only found in periurban areas

Summary

Introduction

Urbanization, understood as the transition of undeveloped land to built-up or sealed areas (Berland 2012), is proceeding at a fast rate in many parts of the world and notably so in developing countries (United Nations 2014). Urbanization has been recognized as the most pervasive and extreme form of habitat transformation (Alberti 2005; Sochat et al 2010), being biotic homogenization one consequence of this transformation (Olden et al 2004; McKinney 2008). Many fast-growing cities are often located in regions with high levels of biodiversity (Liu et al 2003; Pandit and Laband 2007). All of the 35 recognized biodiversity hotspots contain urban areas (Cincotta et al 2000; Mittermeier et al 2011), highlighting the importance of understanding the underlying causes of species loss due to urbanization.

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Results

Conclusion