Various fire-related agents, including heat, smoke, ash and charred wood, have
been shown to break dormancy and promote germination of soil-stored seed in a
broad range of species in mediterranean-type systems. However, relatively
little work has been conducted in south-eastern Australian heathlands. This
study examined the effects of heat and smoked water on germination of the soil
seed bank in a mature sand heathland within the Gippsland Lakes Coastal Park,
in south-eastern Australia. Heat was clearly the most successful treatment for
promoting seed germination, followed by smoked water, then controls, with
55% of species present in the germinable soil seed bank requiring a
heat or smoke stimulus to promote seed germination. Mean species richness of
the germinable soil seed bank was found to be significantly higher in
heat-treated soil than in smoke and control treatments. Seedling density of
heat-treated soil was almost 10 times that of controls, while smoke-treated
soil was almost five times that of controls. Seedling emergence was fastest in
heat-treated soil, followed by smoke and control soils. Of the species found
in the soil seed bank, 25% were absent from the extant vegetation,
suggesting the existence of post-fire colonisers in the soil seed bank. The
results have implications for the design of soil seed bank experiments and the
use of fire as a tool in vegetation management.
