Juvenile period and post-fire recruitment data for threatened Stirling Range Proteaceae

Understanding temporal trends in the populations of threatened flora and how they respond in key demographic parameters to ecological processes are crucial for effective conservation management. We explore patterns of change in abundance over time, predictors of post-fire recruitment success (as measured by the ratio of post-fire seedlings to pre-fire adults) and lengths of juvenile period for four critically endangered obligate-seeder Proteaceae from the Stirling Range (Koi Kyenunu-ruff) in south-western Australia from long-term fixed quadrats and surveys of whole subpopulations. All subpopulations were impacted by one or more fire events over the monitoring period. Banksia brownii and Persoonia micranthera showed consistent decline across all subpopulations and through all fire events. Banksia montana and Banksia anatona showed variation in trends, with some subpopulations having seedling recruitment indicating potential for a degree of population recovery after the most recent fires, but with other subpopulations approaching extinction. The best predictor of greater post-fire recruitment was a larger pre-fire fruit crop, and where this information was not available, a longer preceding fire interval. Post-fire recruitment of Banksia brownii was lower on drier and more exposed topographic positions, providing evidence of directional post-fire reassembly towards putative climate refuges and indicating that climate change is an increasing pressure on populations. Juvenile periods of the four species were long in the context of the broader south-west Australian region, and together with the post-fire recruitment data, indicate that species recovery will be greater with multi-decadal fire intervals. Acquiring detailed population and demographic information through consistent long-term monitoring provided a strong basis on which to quantify responses to threats and prioritise recovery actions.