The Effect of Disturbance Regime on Darwinia glaucophylla (Myrtaceae) and its Habitat

Abstract

The effect of disturbance regime (time since last fire or slashing) on the vulnerable plant species, Darwinia glaucophylla, was assessed on the Central Coast of New South Wales, Australia. The abundance, growth and flowering of D. glaucophylla adults and abundance and growth of seedlings was measured within sites that had either been recently burnt (≤ 5 years), long unburnt (≥ 14 years) or regularly slashed (30 cm above ground) along a utility easement. Our results showed that D. glaucophylla was most abundant at slashed sites, followed by recently burnt sites; it was present but not abundant at unslashed sites that were burnt ≥ 14 years ago. Seedlings were only found at one, recently burnt site. Disturbance regime had no significant effect on the timing or density of flowering. Fruit collected from sites with different disturbance regimes did not germinate after exposure to various combinations of heat, smoke-water and/or scarification. Recently burnt sites contained plants producing a signifi cantly greater number of viable fruits compared to those from other disturbance regimes. Fire and slashing altered the habitat of D. glaucophylla in different ways. Our findings suggest that slashing promotes favourable conditions for adults by creating a habitat with higher light and less competition. However, it is not apparent whether these same conditions are favourable for seedling recruitment.