Ecological Responses to the Reintroduction of Cultural Burning in Box-Gum Grassy Woodlands
Abstract
For tens of thousands of years, Australian Aboriginal communities have shaped many landscapes through the intentional use of cultural burning. However, the comparatively recent exclusion of this practice in critically endangered box-gum grassy woodlands on Wiradjuri and Ngunnawal Countries has contributed significant degradation and management challenges. Programs supporting the re-introduction of cultural burning must be grounded in an understanding of how potential drivers of ecosystem function may be directly or indirectly aTected by fire. My honours project aimed to address key knowledge gaps regarding the influence of cultural burning on biomass accumulation (grass and leaf), soil characteristics, and decomposition activity, and how these interactions may underpin ecosystem response. Specifically, my project answered the following research questions; 1) How does biomass (grass and leaf litter) respond to cultural burning 20 months after fire? 2) How do soil characteristics and decomposition dynamics drive variation in biomass response to burning? and, 3) How does decomposition respond to cultural burning, and how do soil properties influence decomposition? This project took place across 12 sites of varying ecological condition located on Wirajduri and Ngunnawal Country. Sites underwent cultural burning in spring 2023 and were monitored in a before-after-control-impact experimental design, with biomass surveys (grass and leaf litter) conducted before burning in 2023, and again 20 months after burning in autumn 2025. In order to identify key drivers of biomass response, as part of 2025 surveys, I conducted a novel decomposition experiment based on the Teabag Index (Keuskamp et al. 2013) and collected soil samples for nutrient analysis. I found that cultural burning eTectively reduced leaf litter and grass biomass, with potential benefits for native diversity and ecosystem function. I also found that phosphorus concentration was a key driver of grass biomass and may require further management intervention to ensure elevated nutrients do not reduce positive eTects of burning. I also found that decomposition dynamics interacted strongly with phosphorus and carbon cycling, and that fire-induced changes in pH may reduce decomposition activity. My project joins a growing body of literature advocating for the re-introduction of cultural burning as a strategy for reducing biomass accumulation in box-gum grassy woodlands, and also as an opportunity to restore connection to Country and knowledge exchange among Indigenous communities.