Endemism
 

Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the island of Madagascar; none are native elsewhere. The extreme opposite of endemism is cosmopolitan distribution.

Physical, climatic, and biological factors can contribute to endemism. The Orange-breasted Sunbird is exclusively found in the fynbos vegetation zone of southwestern South Africa. Political factors can play a part if a species is protected, or actively hunted, in one jurisdiction but not another.