The tropical savannas of northern Australia are among the most fire-prone ecosystems on Earth, with up to half of many savanna landscapes, including the Tiwi Islands, being burnt each year. Fire plays a key role in maintaining the open vegetation structure that most savanna plants and animals require. However, there is concern that fire frequency in some areas is too high, and that this is having a negative impact on biodiversity.
Savanna fires also have an important influence on greenhouse gases. They make a significant contribution to the nation’s accountable (non-CO2) emissions through the release of methane and nitrous oxide. Savannas contain about 30 per cent of Australia’s terrestrial carbon stocks, and fire also influences rates of carbon sequestration through its effects on tree growth and survival, litter decomposition and charcoal production.
Burning is an important land management tool for Tiwi people, and there is growing concern about the potential negative impacts of more intense fires occurring late in Kumunupunari - the dry season. Most emissions from burning are generated by these fires that sweep through remote areas on the Tiwi Islands from late August onwards. As well as producing greenhouse gases, fires late in the dry season can threaten biodiversity. Reducing the extent of fires can earn carbon credits, representing an economic opportunity for the Tiwi Islands. In 2009, the Tiwi Land Council commenced the Tiwi Carbon Study, in partnership originally with CSIRO but now Charles Darwin University. In 2016, the Tiwi Islands Savanna Burning for Greenhouse Gas Abatement project was registered with the Australian Government’s Emissions Reduction Fund, allowing Tiwi people to earn carbon credits.
Fire Management Plans
The Tiwi Islands Fire Management Committee produces annual management plans. A primary aim of the plans is to reduce the extent and severity of fires on the Tiwi Islands, and thus the levels of greenhouse gas emissions.
Tiwi Fire Management Plan 2017
Tiwi Fire Management Plan 2016
Tiwi Fire Management Plan 2015
Tiwi Fire Management Plan 2014
Weeds and Fire
Tiwi people live in small communities and permanent outstations that are closely connected with the surrounding bush. Compared to the rest of the islands, these areas have the largest infestations of weeds such as Mission grass (Pennisetum polystachion) and Guinea grass (Megathyrsus maximus), which have much higher fuel loads than native grasses resulting in much higher fire intensities, especially later in the dry season. Such fires contribute to soil erosion, destruction of native vegetation and habitat decline. They also present a significant risk to property and even to people’s lives.
The plantation species, Acacia mangium, is sensitive to fire, especially when young, and the protection of plantation areas from fire is crucial to the success of the Tiwi forestry industry. Fire management strategies, focussing on hazard reduction early in the dry season to protect plantations against late dry season fires, have been developed in consultation with Tiwi Landowners.