REGENERATION AND SURVIVAL OF INDIGENOUS DRY SCLEROPHYLL SPECIES IN THE BRISBANE RANGES, VICTORIA, AFTER A PHYTOPHTHORA-CINNAMOMI EPIDEMIC

Changes in the distribution of both pathogen and flora provided data o n pathogen decline and on survival, colonisation and regeneration of p lant species in defined plots in open dry sclerophyll forests of the B risbane Ranges 23-30 years after invasion by Phytophthora cinnamomi. T he density of the stringybark eucalypts (Eucalyptus informal subgenus Monocalyptus) which dominate the overstorey was halved on some plots. The survivors now show vigorous crown growth but few seedlings are pre sent. Regeneration of the understorey occurred in three stages. Firstl y, resistant sedges and then seedlings of resistant opportunists rapid ly colonised ground left vacant by the destruction of the dominant und erstorey species, Xanthorrhoea australis. In the second stage, moderat ely susceptible species such as Banksia marginata and Grevillea steigl itziana resprouted from old stumps and prostrate legumes increased the ir ground cover. In the third stage some highly susceptible species, s uch as X. australis, Dillwynia glaberrima, Hibbertia stricta and Monot oca scoparia have regenerated from seed on sites previously badly affe cted by the pathogen. Some plants of these species have survived for 1 0 years, despite the continued presence of scattered pockets infected with of P. cinnamomi. However, Isopogon ceratophyllus, frequent in the understorey of the plot prior to disease, has not regenerated.