An overview of the patterned fens of Great Sandy Region, far eastern Australia

As far as is currently known, patterned fens of the Great Sandy Region (GSR; Australia) are globally unique in that they arise from the particular hydrological characteristics of a sub-tropical coastal dune system. This article outlines their extent, distribution, characteristics, values and threats. Seven distinct clusters of fens, containing 700 ha of obvious ‘patterning’ resembling that in temperate mires, cover a total area of around 7,000 ha within largely acidic (pH < 5) wet heath ecosystems. Unlike patterned mires in the Northern Hemisphere dominated by Sphagnum (moss) species, these examples are dominated by the restiad species Empodisma minus. Habitat is provided for many endangered fauna including frogs and fish adapted to the unusually acidic conditions. All of the GSR fens fall within the proposed Great Sandy World Heritage Area. The carbon sequestration process that characterises peaty environments makes these fens a fertile source of information on many aspects of environmental history. They are intrinsically sensitive to fluctuations in rainfall, evaporation and sea level, and thus to climate change. A more direct key threat is extraction of resources including, notably, groundwater. However, the fens have remained largely free from human disturbance since the early Holocene and, with their identification and recognition, the challenge now is to maintain these systems in their natural state and continue benefiting from the ecosystem services provided as a result of their excellent condition.