The peatland ecosystems of K’gari (Fraser Island – the world’s largest sand island) and elsewhere on the coastal Cooloola sand mass of SE Queensland, form patterned fens created by the growth of the wire rush, Empodisma minus. The roots and litter of E.minus have created peat layers several metres thick and thousands of years old. Peat cores exhibit charcoal layers showing the regular occurrence of fires which were more common prior to European colonisation, suggesting the role of indigenous fire management.
The dense Empodisma root masses hold water like a sponge, protecting the plants and underlying peat from fire and enabling the plants to resprout following burning. Fires suppress competitors such as Leptospermum, Banksia, Melaleuca and Drosera, supporting the dominance of Empodisma. The acidic pools of the patterned fens support diverse aquatic invertebrates (over 40 taxa recorded so far - including a novel isopod), and threatened fish and frogs. The sand yabby, Cherax robustus digs burrows which provide shelter for other fauna during fires.
Our recent research on 8 peatlands on K’gari with varying fire histories (their most recent fires between 2008-2020) suggests that hydrological conditions, particularly the source of groundwater, have a greater impact on invertebrate community abundance and composition, and leaf litter decomposition (leaves of Macaranga tanarius and E.minus) than time since the last fire.
Whereas tropical and boreal peat fires are typically catastrophic, sometimes lasting years, destroying flora, fauna and peat layers, this did not occur in the intense 2020 fires on K’gari which burnt over 70,000 hectares. Despite evidence of a strip of burnt peat several metres wide on the edge of one patterned fen (Moon Point), further peat burning was not observed and the flora and fauna recovered well. Consequently, unlike tropical and boreal peatlands, the peatlands of SE Queensland are resistant, resilient and fire dependent.