XVI International Botanical Congess

Prolonged storage of seeds on the plant is called serotiny. It is well represented in fire-prone, nutrient-poor and seasonally dry sclerophyll vegetation in Australia, South Africa and North America. Serotiny maximises the number of seeds available for the next generation by storing successive seed crops and protecting them from granivores and fire heat. Their synchronised release satiates post-dispersal granivores and ensures arrival on a seed bed conducive to seedling recruitment. Our recent work has shown that nonsprouters are more likely to retain a greater proportion of viable seeds than resprouters (Lamont and Groom 1998). Modelling showed that, as the probability of interfire recruitment increased, maximum population growth shifted from strong serotiny under short fire intervals, to no serotiny for long fire intervals (Enright et al. 1998). As variation about the mean fire interval increases, so optimal level of serotiny declines. Other modelling indicated that the optimal fire interval depends on how long the seeds survive on the plant (Drechsler et al. 1999).