Secondary Succession in Post-Fire Scrub Dominated by Acacia verticillata (L'hérit) Willd at Wilsons Promontory, Victoria

Abstract

Senescence and death of 30-year-old post-fire Acacia verticillata scrub in areas originally supporting sclerophyll eucalypt forest were studied over a 6-year period at Wilsons Promontory, Victoria. The potential for eucalypt regeneration was also examined. On drier sites, A. verticillata has been replaced by drought-resistant Kunzea ambigua while on wet sites it has been replaced by waterlogging-tolerant Melaleuca ericifolia. In mid slopes A. verticillata is regenerating from soil seed in gaps in the field layer of Pteridium esculentum and Goodenia ovata and forming a patchy, uneven-aged stand. The composition of the mid-slope community is determined by the relative resistance of species to browsing and grazing. The failure of eucalypts to reclaim the scrub areas at this critical time has been due to poor seed crops, seed harvesting by ants and intense selective browsing. Exclosure plots have demonstrated the importance of herbivory in modifying this vegetation and indicate potential means of reafforestation without the intervention of fire.