Range size and extinction risk in forest birds
1Nicholas School of the Environment and Earth Sciences, Duke University, NC 27708, USA. gmharris@fs.fed.us
Summary
A new protocol identifies a 11,000 km2 threshold for forest bird extinction risk. This helps predict species vulnerability to habitat loss and climate change, aiding conservation efforts.
Area of Science:
- Ecology
- Conservation Biology
- Ornithology
Background:
- Small geographical range size is a primary indicator of extinction threat in terrestrial species.
- Predicting species' extinction risk requires understanding the range size threshold for threat designation.
- Deforestation and climate change exacerbate extinction risks for species with limited ranges.
Purpose of the Study:
- To determine the range size threshold at which forest-dependent bird species are considered threatened with extinction.
- To develop a practical protocol for quantifying species' remaining suitable range.
- To identify at-risk bird species with small, but not yet officially threatened, ranges.
Main Methods:
- Compared range sizes of threatened and nonthreatened forest-dependent bird species.
- Developed a protocol to quantify remaining suitable range by considering elevation, forest type, and remaining forest cover.
- Validated range estimates against World Conservation Union Red List data.
Main Results:
- Established a threshold of 11,000 km2 for remaining suitable range below which bird species are considered threatened.
- Identified 18 non-threatened species (approximately 11% of analyzed) with ranges below this threshold.
- These species are at high risk of extinction and require urgent status reevaluation.
Conclusions:
- The 11,000 km2 threshold provides a quantifiable baseline for assessing extinction risk in forest birds.
- The developed protocol offers a repeatable method for estimating species' remaining suitable habitat.
- Proactive conservation and reevaluation of species with small ranges are crucial for preventing extinctions.
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