Most ecological communities are defined by their dominant species.
- In many examples of wet woodland in western Europe, the dominant tree is alder (Alnus glutinosa).
- In temperate bogs, the dominant vegetation is usually species of Sphagnum moss.
- Tidal swamps in the tropics are usually dominated by species of mangrove (Rhizophoraceae)
- Some sea floor communities are dominated by brittle stars.
- Exposed rocky shorelines are dominated by sessile organisms such as barnacles and limpets.