Tropical cities lost more of their local bird richness than higher-latitude cities
WHAT THE EVIDENCE SAYS
An analysis using eBird observations for more than 10,000 bird species compared species richness in spatial cells across urbanization classes. Near the equator, urban cells averaged 42% fewer species than nearby natural areas, versus a 32% worldwide average and 12% fewer around 65 degrees latitude.
WHY IT MATTERS / OUR READ
A city can have trees and green space yet still sharply filter the regional fauna. Landscape planning in biodiverse tropical settings should protect habitat configuration and native ecological interactions, not count canopy cover as a substitute for species retention.
CAVEATS / UNCERTAINTY
Comparisons are observational and depend on citizen-science sampling coverage and which cells meet completeness thresholds. Species richness alone does not describe community composition or causal mechanisms.
SOURCE
Proceedings of the National Academy of Sciences · global eBird analysis
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McGill University research summary
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Global eBird-based research finds urbanization weakens the familiar rise in biodiversity toward the equator.
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