Fire on a tropical floodplain: a fine-scale fire history of coastal floodplains in the Northern Territory, Australia

Background. The coastal floodplains of northern Australia are fire-prone, but the impact of fire on floodplain biota is not well understood. Aims. In this study, we sought to characterise the fire history of six adjacent floodplains in coastal Northern Territory, Australia. Methods. We built a fine-scale 31-year fire history (1988-2018) to compare fire regimes on floodplains across land tenures and floodplain fire regimes with the surrounding savanna fire regime, determine the extent to which current fire regimes are meeting existing ecological fire thresholds, and investigate the relationship between rainfall totals and the extent of burning. Key results. Floodplains in conservation reserves burnt more frequently than those on pastoral lands, and savannas burnt more often than floodplains. Current floodplain fire regimes comfortably meet existing ecological fire thresholds. The proportion of floodplain burning is inversely proportional to the amount of rain in the previous wet season. Conclusions. Floodplain fire regimes vary markedly between land-use types, and floodplain fire regimes differ to those of savannas. The current management thresholds for floodplain fire regimes would benefit from further evidence of conservation outcomes.Implications. For more effective floodplain fire management, research is needed to generate floodplain-specific thresholds that best conserve their considerable conservation value.

Automated summary

This study aimed to characterize the fire history of floodplains in coastal Northern Territory, Australia. It was found that floodplains in conservation reserves experienced more frequent fires compared to those on pastoral lands, and floodplain fire regimes differed from savanna fire regimes. Further research is needed to establish floodplain-specific fire management thresholds.