Forest in a tropical region of Equator has ten times more vascular plants than a forest in temperate region of Midwest of the USA, although both are equal in terms of area. This is an example of

A forest in a tropical region like Equador has up to 10 times as many species of vascular plants as a forest of equal area in a temperate region like the Midwest of the USA. Latitudinal gradient in diversity is observed in this case. In general, species diversity decreases as one moves away from the equator towards the poles. With very few exceptions, tropics (latitudinal range of 23.5° N to 23.5° S) harbour more species than temperate or polar areas.