Influence of multiple fire-related germination cues on three Sydney Grevillea (Proteaceae) species

Many species found in fire-prone habitats that possess a soil-stored seedbank: only recruit seedlings in large numbers following a fire. Fire-related germination cues are presumably used by these seeds as signals that a fire has occurred, and would include the heating that occurs in the soil and the combustion products of burning vegetation, smoke and charcoal. Three Sydney species, Grevillea buxifolia (Sm.) R. Br., Grevillea sericea (Sm.) R. Br. and Grevillea speciosa (Knight) McGillivray, were studied for the interactive effects of these cues on their germination. The germination of all species was found to increase with both smoke and heat treatments. While smoke always had a greater influence than heat, the relationship between the two treatments varied with species. The presence of two fire-related germination cues should allow these species to take better advantage of the recruitment opportunities of the post-fire environment.