The effect of inter-fire interval and fire severity on seedling germination and resprouting in

Abstract

Context Regeneration from seed and resprouting are life-history strategies used by plants in fire-prone landscapes; however, for some species there is a limited understanding of how different factors influence post-fire response within populations. Aims We studied the effect of inter-fire interval and degree of tree burn on post-fire seedling germination and basal resprouting in Allocasuarina verticillata within two conservation parks on Kangaroo Island. Methods We undertook seedling counts using 1 m2 quadrats. Burnt trees were assessed for signs of resprouting. Key results Seedling density 8–9 months post-fire was primarily influenced by interfire interval, and was higher in stands with an inter-fire interval time of 37–45 years (143 per m2) compared to those with an interval of >60 years (48 per m2). Resprouting in burnt A. verticillata trees was influenced by the degree of tree burn, but also varied considerably between the two parks. Conclusions Our study confirmed that A. verticillata is a facultative seeder/resprouter that can regenerate from both seedling germination and resprouting post-fire. However, the two strategies are influenced by different factors, and resprouting rates in A. verticillata can be very low in some circumstances. Implications Because A. verticillata relies primarily on seedling germination for population persistence post-fire, it may be vulnerable to drastic changes in fire frequency. Further research is required on the minimum inter-fire interval for persistence of this species within a landscape.