Researchers have created a database bringing together records of fire across Australia and New Zealand over thousands of years, which offers insights into how bushfires may be changing.
Eastern Australia is one of the most fire-prone regions in the world, with bushfires responsible for the death of around 800 people and millions of animals since around 1850.
The new SahulCHAR database is a collection of sedimentary charcoal and black carbon records from the paleocontinent Sahul (Australia, New Guinea, and offshore islands) and New Zealand/Aotearoa.
Sedimentary charcoal can provide insights into fire frequency, intensity and the types of vegetation that burned in the past, with the charcoal from bushfires moved by wind and water and preserved in lakes, swamps and other sedimentary environments.
James Cook University's Dr Emma Rehn was the lead researcher and said the databasecompiles original data from 23 scientific contributors along with records from existing databases and academic publications, providing a critical tool for understanding the long-term context of future fire risks in a changing climate.
"The only way to know if fire patterns are changing is to have previous records of what it was like before. We want to ensure that future research into global trends in past fire uses comprehensive, up-to-date data from our region," Dr Rehn said.
"In many recent studies of ancient fire histories, we're trying to tease out human influences on fire, particularly Indigenous cultural burning, and distinguish these from climate-driven fire patterns.
"Having this kind of information is a good complement to historical fire records and modern observations. As things continue to change, we want to be able to look back and understand the context."
Dr Rehn said records collected in their database reveal how fire behaviours have transformed over time and will provide land managers, policymakers, and climate scientists with a valuable tool for understanding how changing fire conditions compare to long-term trends.
"If you suddenly get more fires than you used to have - when fire was rare for thousands of years - that tells you something significant about ecosystem changes," Dr Rehn noted.
Records of past fire (palaeofire) have long provided valuable insights in this field and the collaborative nature of the project helps address a lack of recent data in Australia and surrounding regions in current international databases.
"We ended up having 23 researchers contributing their own original data... everyone was enthusiastic about getting involved and making the data accessible in one place," Dr Rehn said.
"We want to make sure that the next time someone does a global synthesis of fire data, they're not using really old or really patchy data from Australia and New Zealand when so much new research exists.
"These records help us to understand the deep history of landscapes - what was happening in terms of fire 50 years ago versus 1000 years ago versus 3000 years ago."
"In a lot of places in Australia, written records of what's happening in terms of fire don't go back very far. In those cases, turning to the sedimentary record is the only way to understand fire history."
Data creators with char records from Australia, New Guinea, or New Zealand/Aotearoa that they would like to contribute can use a SahulCHAR data template (https://doi.org/10.5281/zenodo.10117180; Rehn, 2023) and can contact Dr Haidee Cadd ([email protected]) with enquiries or to submit completed data templates.
