Indigenous impacts on north Australian savanna fire regimes over the Holocene

Abstract
Fire is an essential component of tropical savannas, driving key ecological feedbacks and functions. Indigenous manipulation of fire has been practiced for tens of millennia in Australian savannas, and there is a renewed interest in understanding the effects of anthropogenic burning on savanna systems. However, separating the impacts of natural and human fire regimes on millennial timescales remains difficult. Here we show using palynological and isotope geochemical proxy records from a rare permanent water body in Northern Australia that vegetation, climate, and fire dynamics were intimately linked over the early to mid-Holocene. As the El Niño/Southern Oscillation (ENSO) intensified during the late Holocene, a decoupling occurred between fire intensity and frequency, landscape vegetation, and the source of vegetation burnt. We infer from this decoupling, that indigenous fire management began or intensified at around 3 cal kyr BP, possibly as a response to ENSO related climate variability. Indigenous fire management reduced fire intensity and targeted understory tropical grasses, enabling woody thickening to continue in a drying climate. © 2024 Springer Nature Limited. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Description
Keywords
Fires, Australia, Indigenous peoples, Geochemistry, Climates, Isotopes, Palynology, Tropical Regions, Southern Oscillation, Pleistocene Epoch, Revegetation, Water
Citation
Wurster, C. M., Rowe, C., Zwart, C., Sachse, D., Levchenko, V., & Bird, M. I. (2021). Indigenous impacts on north Australian savanna fire regimes over the Holocene. Scientific Reports, 11(1), 23157. doi.org/10.1038/s41598-021-02618-z
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