Response to ‘Fire practices only ‘best’ if they promote a large seed buildup: comment on the conservation needs of a fire-killed grevillea’ (Lamont 2022)

Abstract

Lamont (2022) re-assessed our data (McKemey et al. 2021b) related to the population dynamics of Grevillea scortechinii subsp. sarmentosa, in response to different types of fire. The original data were collected through our ongoing cross-cultural research and presented in our paper, 'Indigenous cultural burning had less impact than wildfire on the threatened Backwater grevillea (Grevillea scortechinii subsp. sarmentosa) while effectively decreasing fuel loads' (McKemey et al. 2021b). We thank Professor Lamont for increasing our understanding of the population dynamics of this rare plant, which will inform the Banbai Rangers' custodianship of the Backwater grevillea and our long-term monitoring program. In response to Lamont's comments on our paper, we wish to make three important points around Lamont's analysis and the lack of acknowledgement of the benefits of cultural burning and cross-cultural research.Firstly, our paper concluded that cultural burning resulted in a multi-age population. The mature shrubs that survived the cultural burns continued to contribute to the seed bank, and the seedlings that recruited as a result of the cultural burns provided the next generation of grevilleas. In contrast, the wildfire resulted in mortality of almost all (99.6%) of the aboveground grevillea population. In the culturally burnt plots, the mature shrubs were observed to produce large quantities of seeds and were, we would suggest, in the 'prime' of their seed production capacity or demographic rate (Harper and White 1974;Enright et al. 2015). Therefore, protecting these shrubs from destruction by wildfire was considered to be a priority conservation action. We question whether Lamont's reassessment of population size considered the variation in seed production capacity of young versus older adult plants. The recovery process for the grevillea following the cultural burn was enhanced by having the seed bank continually replenished by the remaining mature plants, whereas after the wildfire there was a lag time in which initially there were no adult plants, and following this, young adult plants with a comparatively low seed production capacity. Our ongoing research at this site aims to continue collecting data, with the aim of quantifying seed production of plants in relation to time since fire (i.e. the age of the different cohorts). In line with Lamont's comments, we are also investigating time to maturation and other aspects of the fire response of the Backwater grevillea. Our paper acknowledged that, like all scientific pursuits, we cannot measure every parameter possible, and like Lamont, we recommended that future work should measure more variables, including the seed bank.Secondly, Lamont overlooked some of the benefits of using cross-cultural science in monitoring the grevillea. The Backwater grevillea is on the traditional lands of the Banbai people, who regained legal custodial responsibility for managing this site in 1996. The Banbai have observed and monitored changes in the grevillea during this time with gre...