Bushfire season in Australian Indigenous seasonal calendars and associated drought trends

Abstract

Climate-induced changes in rainfall and temperature across Australia exacerbate drought and bushfire risk which have detrimental impacts on flora, fauna, and water quality. Indigenous Peoples across Australia have recorded climate, environment, and biotic patterns in seasonal calendars, of which five are used to delineate approximate time windows associated with bushfire to demonstrate the necessity of weaving non-colonial and colonial knowledge for better understanding modern climate challenges. The bushfire season (October–March) was examined for variability and trends in the Standardised Precipitation Evapotranspiration Index (SPEI), the Southern Oscillation Index (SOI), and the Indian Ocean Dipole (IOD) historical data from 1950 to 2021. SPEI is an integrative measure of local land-atmospheric conditions and affords physics-based monitoring of drought conditions across large spatial scales, using temperature, precipitation, and potential evapotranspiration to evaluate moisture content in a region. We found that drought indices showed moderate correlations with climate variables (SOI and sea surface temperatures). Taken together, this study illustrates overlapping scales of Indigenous and western knowledges in the context of bushfire risk and has the potential to enhance and inform climate adaptation efforts. HIGHLIGHTS Australian Indigenous seasonal calendars are used to delineate the bushfire season.; SPEI integrates hydroclimatic variability and offers insights regarding drought risk.; Spatial trend patterns show region wide and local patterns of variability.; Moderately strong relationships present between SOI and leading patterns of SPEI.; Integrative view provided through knowledge delineated from seasonal calendars and hydroclimatic data.;

Keywords

• australia
• bushfire
• climate change
• drought
• indigenous
• water deficits