 Areas available for plant colonisation on Heard Island are generally the result of retreating glaciers or new ice-free land created by lava flows.Today, substantial vegetation covers over 20 km2 of Heard Island, and is best developed on coastal areas at elevations below 250 m.

Bryophytes (mosses and liverworts) contribute substantially to the overall biodiversity of Heard Island, with 43 mosses and 19 liverworts being recorded, often occupying habitats unsuitable for vascular plants, such as cliff faces.Bryophytes are present in most of the major vegetation communities including several soil and moss-inhabiting species.