Biodiversity declines with increasing distance from the equator, such that tropical regions near the equator harbor more species than temperate or polar regions further from the equator. This pattern is demonstrated by countries like Colombia, located near the equator, having over 1400 bird species, compared to places like New York at 41°N only having 105 bird species. Tropical forests at the equator can have ten times more vascular plant species than forests of equal area in temperate regions. This distribution of species can be studied under latitudinal gradients and species-area relationships.