Biological characteristics of Australian threatened birds

ABSTRACT

Over 750 native bird species reside in or regularly migrate to Australia, many of which have experienced rapid changes in habitat extent over the past two centuries. By 2020, eight taxa were considered Extinct and 10% threatened with extinction. Understanding the underlying extrinsic and intrinsic factors that increase extinction risk can allow prioritisation of conservation management and research. Here, we use state-of-the-art phylogenetic comparative models to reveal the most important biological traits that predispose Australian bird species to elevated extinction risk. We use an extensive database of their biological traits and relate these to each species’ national and global IUCN extinction risk status as assessed over the past three decades (in 1990, 2000, 2010, and 2020). We show that high evolutionary distinctiveness (uniqueness), island endemism, and an inability to take advantage of agricultural habitats were the most important traits explaining elevated extinction risk in species when phylogeny is controlled for, suggesting that extinction risk is disproportionately high in species with high evolutionary distinctiveness. Extinct taxa were characterised by large body mass and island endemism compared to taxa extant in 2020. Our study provides the largest and most up-to-date analysis of the intrinsic traits of Australian birds in relation to their extinction risk, and can be used as a baseline in future studies, for prioritisation of conservation actions, and for policy advice on a broad scale.

Key policy highlights

• Phylogenetic analyses are a useful tool for anticipating extinction risk.

• Extinction risk over the past three decades is highest among species with a high level of evolutionary distinctiveness.

• Species-level assessments can mask higher extinction risk at the subspecies-level.

• Conservation actions that reduce extinction risk can influence the variables deemed important in predictive models.

KEYWORDS:

• IUCN Red List
• extinction risk
• Australia
• comparative models
• evolutionary distinctiveness
• uniqueness

Acknowledgments

We thank all those who contributed to the Red List assessments in Australia (see Garnett and Baker 2021), which were used by the models of this study, as well as the many individuals and institutions involved in monitoring the status of Australia’s birds. We are grateful to helpful comments from three anonymous reviewers.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The complete dataset used in this study is available as supplementary online material.

The phylogenetic tree is available in zoomable digital version at https://itol.embl.de/shared/olahgy.

Supplementary data

Supplemental data for this article can be accessed at https://doi.org/10.1080/01584197.2023.2285821.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Assessments of extinction risk for Garnett and Baker (2021) were supported financially by the Australian Bird Environment Fund, BirdLife Australia, Charles Darwin University, Biosis Pty Ltd, and Auchmeddan. G.O. was funded by Australian Research Council DECRA Fellowship [DE230100085].