Global Patterns of Geographic Range Sizes: A Bird's Eye View
2006
Global Patterns of Geographic Range Size in Birds
Sample size: 9500
publication
Evidence: moderate
Author Information
Author(s): David Orme, Kevin Gaston
Hypothesis
Do spatial patterns of range size in birds follow a simple north-to-south rule?
Conclusion
Birds do not follow a simple north-to-south rule in their geographic range sizes, with the smallest ranges found on islands and in the southern hemisphere.
Supporting Evidence
- More than a quarter of bird species have ranges smaller than 86,872 square miles.
- The smallest ranges are found on islands and in low-altitude mountains.
- Species richness is highest in the tropics and subtropical regions.
Takeaway
This study looks at where birds live and finds that many have small homes, especially on islands and in mountains, and that their range sizes don't just get smaller as you go south.
Methodology
The researchers analyzed breeding ranges for over 9,500 bird species using published data and mapped these ranges to calculate their sizes.
Limitations
The study excluded marine species, which have different range characteristics.
Digital Object Identifier (DOI)
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