Modelling the persistence of an apparently immortal Banksia species after fire and land clearing

Abstract

A stage-based model was developed for the population dynamics of Banksia goodii, a rare long-lived shrub in Western Australia. While few seeds are produced, death of adults due to senescence or fire has yet to be observed. A sensitivity analysis showed that population growth is close to zero as long as post-fire mortality and recruitment are within their usual low bounds. To remain viable, the size of a population remnant should exceed about 80 individuals. If fires occur at random intervals, an average of one fire in 10-15 years is optimal. Regular fires should have inter-fire periods of 15-20 years. Loss of adult plants due to human activities, such as land clearing, will increase mortalit..