Why the tropics lose the most birds when cities expand |
Tropical ecosystems are famous for their teeming, exuberant diversity. In fact, the dramatic increase in biodiversity from the poles to the tropics — known as the latitudinal diversity gradient — is pervasive across branches of the tree of life, and fossil evidence suggests it has existed for millennia.
It might seem that if anything could be immune to human disruption, it would be the latitudinal diversity gradient. But human impacts on nature are also global, pervasive and dramatic. One of the most dramatic is urbanization.
Urbanization replaces natural ecosystems with environments dominated by pavement and buildings. Wetlands are drained, deserts are irrigated and grass lawns are planted.
Urbanized landscapes are much more similar to each other than the ecosystems they replace, so much so that urbanized areas have been called the fastest-growing biome on the planet. Unlike any natural biome, urbanized landscapes now exist from the Arctic to the equator.
Ecologists have known for decades that urbanization generally lowers local diversity. We wanted to know if urbanization........