North Queensland Naturalist

Abstract

Montane heath on Hinchinbrook Island and adjacent mainland of the southern Wet Tropics is of conservation significance, due to the restricted distribution of the ecosystem and the co-dominant shrub Banksia plagiocarpa (Blue Banksia). Fire is the primary land management action and it has previously been established that B. plagiocarpa is killed by fire, while the other dominant shrub Allocasuarina littoralis (Montane Oak) can survive fire via coppice shoots. This study provides further specifics about the fire ecology of A. littoralis and B. plagiocarpa. Observed fires were patchy, and long unburnt heath appeared to be senescing. Around half of A. littoralis plants survived fire by coppicing and quickly regrew towards pre-fire stem heights, although age to seed production by seedlings remains unknown. Banksia plagiocarpa has fire-promoted seedlings that grow slowly, averaging around 30 cm at three years of age and begin to produce seed in their fifth year. It is proposed that current recommendations of patchy burns every six to ten years be extended to predominantly 10 to 20 year intervals to allow adequate seed production, with occasional more frequent fires and some longer unburnt patches. Patchiness can be achieved by burning with good soil moisture and igniting from ridges downwards. We recommend that montane heath populations of A. littoralis receive taxonomic assessment as a potential distinct subspecies because they differ from forest populations in being shrubby and resprouting.