A review of the impacts of air pollution on terrestrial birds

Birds and chimney, Gallinago Media/Adobe Stock

Author(s): Barton, M.G., Henderson, I., Border, J.A. & Siriwardena, G.M.

Published: February 2023  

Journal: Science of The Total Environment Volume: 873

Article No.: 162136

Digital Identifier No. (DOI): 10.1016/j.scitotenv.2023.162136

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A review paper by BTO considers 203 studies of the effects of air pollution on 231 bird species. Of these studies, 82% document at least one negative effect associated with increasing levels of pollution. The review also highlights biases towards particular study species, especially Great Tit and Pied Flycatcher, and also towards particular geographical regions (Western Europe) and pollutants (heavy metals). The paper proposes research approaches that could help to provide a fuller understanding of how birds are impacted by air pollution.

Abstract

Air pollution has a ubiquitous impact on ecosystem functioning through myriad processes, including the acidification and eutrophication of soil and water, deposition of heavy metals and direct (and indirect) effects on flora and fauna. Describing the impacts of air pollution on organisms in the field is difficult because levels of exposure do not occur in a uniform manner across space and time, and species responses tend to be nuanced and difficult to isolate from other environmental stressors. However, given its far-reaching effects on human and ecosystem health, the impacts of air pollution on species are expected to be substantial, and could be direct or indirect, acting via a range of mechanisms. Here, we expand on previous reviews, to evaluate the existing evidence for the impacts of air pollution on avian species in the field, and to identify knowledge gaps to guide future research. We identified 203 studies that have investigated the impacts of air pollution (including nitrogen and heavy metal deposition) on wild populations of birds, considering 231 species from ten feeding guilds. The majority of studies (82 %) document at least one species trait leading to an overall fitness value that is negatively correlated with pollution concentrations, including deleterious effects on reproductive output, molecular (DNA) damage and overall survival, and effects on foraging behaviour, plumage colouration and body size that may show adaptation. Despite this broad range of trait effects, biases in the literature towards certain species (Parus major and Ficeluda hypoleuca), geographical regions (Western Europe) and pollutants (heavy metal deposition), mean that many unknowns remain in our current understanding of the impacts of air pollution on avian species. We discuss these findings in context of future work, and propose research approaches that could help to provide a more holistic understanding of how avian species are impacted by air pollution.

Notes

This study was funded by the UK Joint Nature Conservation Committee.
Staff Author(s)


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