This article is about the ecological meaning of "endemic". See also endemic (epidemiology).

Endemic in biology and ecology means exclusively native to a place or biota. It is in contrast to any one of several terms meaning "not native" (e.g., adventive, exotic, alien, introduced, naturalized, non-native). However it is also differentiated from indigenous. A species that is endemic is unique to that place or region, found naturally nowhere else. A species that is indigenous is native, but not unique because it is also native to other locations as well.

Usually the term is applied to a discrete geographical unit, most often an island or island group, but sometimes a country or other defined area.

Islands are especially likely to develop endemic forms because of their geographical isolation; remote island groups, such as Hawai'i and the Galapagos, have large numbers of endemic species. The restricted area and vulnerability to the depredations of man and introduced species mean that endemics all too easily can become extinct.

Endemics can also develop in other biologically isolated areas, such as the highlands of Ethiopia or large bodies of water like Lake Baikal.

According to the World Wildlife Fund, the following ecoregions have the highest percentage of endemic plants:

• Madagascar lowland forests (Madagascar)
• New Caledonia rain forests (New Caledonia)
• Hawaii tropical moist forests (United States)
• Madagascar dry deciduous forests (Madagascar)
• New Caledonia dry forests (New Caledonia)
• Hawaii tropical dry forests (United States)
• Sierra Madre de Oaxaca and Sierra Madre del Sur pine-oak forests (Mexico, Guatemala)
• Fynbos (South Africa)
• Kwongan heathlands (Australia)