Quantifying the relative irreplaceability of important bird and biodiversity areas

Area of Science:

• Conservation Biology
• Biodiversity Assessment
• Spatial Planning

Background:

• Global commitments aim to expand protected areas for biodiversity conservation.
• Effectiveness of protected areas depends on their spatial location.
• Threshold- and complementarity-based methods are used to identify key biodiversity sites.

Purpose of the Study:

• To integrate threshold- and complementarity-based approaches for biodiversity site identification.
• To analyze the irreplaceability of Important Bird and Biodiversity Areas (IBAs).
• To assess if irreplaceability within IBAs varies based on site characteristics and geographic region.

Main Methods:

• Conducted a complementarity-based analysis of irreplaceability within IBAs.
• Compared irreplaceability values inside and outside IBAs across Australia, southern Africa, and Europe.
• Examined the association between irreplaceability and IBA characteristics (e.g., species composition, criteria used, target setting).

Main Results:

• Irreplaceability values were significantly higher within IBAs compared to outside areas.
• Higher irreplaceability in IBAs correlated with restricted-range species, number of identification criteria, and trigger species' range size.
• IBAs using proportional species targets showed higher irreplaceability than those with fixed targets; trigger species effectively represented overall bird irreplaceability.

Conclusions:

• IBAs, identified via threshold-based methods, effectively capture irreplaceable sites for biodiversity.
• Site characteristics and target setting influence the irreplaceability captured by IBAs.
• Findings inform the development of Key Biodiversity Area (KBA) standards, integrating irreplaceability criteria.