Researchers at McGill University have found that urbanization is weakening one of Earth's most enduring ecological patterns: the tendency for biodiversity to increase toward the tropics, a pattern known as the latitudinal diversity gradient.
Analyzing bird populations worldwide, they found that on average, urban areas near the equator contained 42 per cent fewer species than nearby natural areas, while the comparable global figure was 32 per cent fewer, and 12 per cent fewer at 65 degrees of latitude.














