Management of alien bird impacts does not reflect their severity

Area of Science:

• Ecology
• Conservation Biology
• Environmental Science

Background:

• Biological invasions, particularly by alien birds, pose significant threats to native biodiversity and are a leading cause of species extinctions globally.
• Management of alien species impacts is inconsistent, necessitating an understanding of the factors influencing conservation actions to improve effectiveness.

Purpose of the Study:

• To identify key factors influencing management decisions for alien bird impacts on native fauna.
• To understand why certain biodiversity impacts of alien birds remain unmanaged and inform strategies for more consistent conservation efforts.

Main Methods:

• A comprehensive literature review was conducted to identify and categorize impacts of alien birds on native fauna as managed or unmanaged.
• Data on native species (endemism, threat status), alien species (residency duration), impact severity, and environmental factors (population density) were collected for each impact.
• Binomial mixed effects models were employed to analyze associations between these variables and the likelihood of management actions.

Main Results:

• Management actions disproportionately focus on protecting endemic native species, irrespective of the impact's severity or the native species' overall threat level.
• Impact severity and native species threat status were less influential in driving management decisions than factors like feasibility.
• Long-established alien bird populations with significant biodiversity impacts often remain unmanaged due to perceived high costs and difficulties associated with managing large, widespread populations.

Conclusions:

• Conservation management for alien bird impacts is often driven by feasibility rather than ecological severity or threat, leading to potential neglect of critical threats.
• There is a critical need for timely interventions against biological invasions before impacts become too widespread and costly to manage effectively.
• Improving management consistency requires a strategic shift towards addressing the most ecologically significant threats, regardless of perceived management challenges.