This research presents a method to produce fire reconstructions with a high spatial and temporal resolution by downscaling geostationary satellite observations using a deep learning segmentation framework. This was achieved by training a U-Net on low earth orbit active fire detections paired with synchronous observations from the geostationary satellite Himawari-9/Advanced Himawari Imager (AHI) resampled to the resolution of the 500 m 0.64 mu m RED channel. Geostationary satellites provide a means for continuous monitoring of fire behaviour but are constrained by the low spatial resolution of the infrared channels used to detect active fires. Localising fire activity using information from the higher spatial resolution solar reflective channels of geostationary satellites enables detailed fire progression mapping with a comparable spatial resolution to low earth orbit satellite systems. Six case study fires in the northern Australian savannahs are reconstructed with their lifecycles compared to the burn scar mapped by the Northern Australia and Rangelands Fire Information (NAFI), with F1-scores ranging from 0.80 to 0.96. Model predictions synchronous to VIIRS active fire detections during the selected case study fires were used to test performance during case study events. The results indicate a high positive detection rate (75%) for detections with a fire radiative power (FRP) above 12.4 MW during day-time and 3.1 MW at night-time which degraded with decreasing FRP as the fire signal becomes increasingly difficult to detect within the 2 km instantaneous field of view (IFOV) of the AHI infrared channels against the high day-time background temperatures within the northern Australian savannahs.

The reinstatement of Indigenous fire practices across northern Australia has demonstrated positive biocultural outcomes for local Indigenous communities, including reconnection to culture, Country and biodiversity conservation. However, limited research has specifically investigated the alignment of contemporary Indigenous fire management to fine-grained preferences, values and responsibilities for cultural fire, especially those of Indigenous women. This study incorporated qualitative and quantitative methodologies to assess whether recent fire regimes in the Mimal Indigenous Protected Area (IPA) reflect the preferences and values of Dalabon, Rembarrnga and Mayili women across culturally important places. Contemporary Indigenous women's knowledge and obligations for burning were also elicited, including site-based responsibilities shaped by cultural protocols and kinship roles, ongoing care of culturally significant areas, and responsibilities for intergenerational knowledge transfer. The research indicated substantial alignment of contemporary fire management to traditional and gendered values and responsibilities in caring for Country. All women interviewed had a nuanced understanding of which areas to burn and why, often related to protecting sacred sites, promoting traditional bush foods, and access for hunting or recreation. Some discrepancies between preferences and fire regimes across several cultural sites indicated that more explicit incorporation of broader community values, particularly those of women, into fire management decision-making processes would likely benefit overall cultural and land management outcomes. These findings highlight the importance of engaging Indigenous women and their knowledge in conservation initiatives to help inform community-based decision-making in cultural fire management.

Regional land-use planning for utility-scale solar and wind energy production in the Northern Territory of Australia have been limited in consideration to regional ecological impacts and the long-term conservation of biodiversity policy goals. When conservation is prioritised in planning, rather than considering solely socioeconomic issues, more equitable land use outcomes are likely to be achieved. Here, we review existing formal conservation planning under current land use planning frameworks against bioregional area-based comprehensive and ecosystem representative policy goals for persistence of biodiversity using the Interim Biogeographic Regionalisation for Australia in order to evaluate the threat of spatially cumulative impacts across large regions in the Northern Territory. Bioregional gaps in comprehensiveness and representativeness of ecosystems in recognised conservation areas are most evident on the pastoral lease estate, covering 44 per cent of land in the Northern Territory, with many ecosystems having little protection where land is increasingly being acquired and planned for development. The threat to biodiversity from the cumulative impacts of large centralised solar and wind farms of the type anticipated in the Northern Territory and regional development of other new land uses needs to be managed through strategic spatial planning with the assistance of conservation experts.

Background Savanna ecosystems constitute approximately 20% of the Earth's terrestrial surface and are increasingly under threat from various factors including effects of climate change. In Baikiaea plurijuga-dominated woodlands of Botswana, the combination of destructive fire regimes and large elephant populations has been cited as a major cause of adverse vegetation changes in African savanna and woodland systems.Aims We assessed the status of fire regimes in Botswana's premium wildlife eco-tourism Chobe region to determine whether market-based fire management could be applied to support broader ecological fire management and employment outcomes.Methods The methods used were: (1) reconstructed fire regimes from the early 1990s coinciding with the cessation of commercial timber exploitation; (2) combined automated MODIS 250 m and manually derived Landsat 30 m burn scar products to generate a 33-year Fire Frequency Index (FFI); (3) classified regional vegetation structural types derived from a 5-year (2021-2024) early dry season Landsat median image; and (4) assessed dry season elephant population density distributions in relation to fire occurrence.Key results Frequent (on average, one in every 2.5 years) and relatively severe late dry season fires were characteristic in more open-canopied legume-dominated savannas and grasslands in the eastern sector of the project area. Elephant distributions in the dry season were independent of fire occurrence. Wildfires plausibly cause relatively greater impacts to Baikiaea-dominated vegetation macro-structure than elephants.Conclusions Multiple factors including national fire exclusion policy contribute to contemporary fire patterning in the Chobe regional landscape.Implications We suggest that carbon market-based approaches have potential for contributing to ecologically sustainable fire management and local employment opportunities.

Environmental smoke has been shown to have significant associations with both causation and exacerbation of respiratory conditions. Aboriginal Australians in the Northern Territory (NT) of Australia are disproportionately affected by respiratory illness in comparison with non-Aboriginal Australians. Traditionally, Aboriginal communities have utilized fire for multiple purposes, such as land management practices, cultural ceremonies, hunting, and cooking. In this report, we describe an Aboriginal man who presented with acute exacerbation of airway disease after environmental smoke exposure while being in the close vicinity of "fire hunting" for "mud turtles" from a Top End remote Aboriginal community in the NT of Australia. This report highlights the potential impact of nontobacco environmental smoke exposure contributing to the causation and exacerbation of chronic respiratory conditions among Aboriginal Australians. Hence, further research is warranted to address mitigating strategies in this population.

An increasing number of countries are adopting net‐zero‐emissions targets requiring large‐scale removal of CO 2 ‐e through ecological restoration. Are these plans feasible, and will they transform the realm of restoration ecology? We use Australia's plan for net‐zero emissions as a test case. Widespread degradation across Australia's ecoregions, from savannas to seagrasses, provide opportunities for restoration, producing “negative emissions.” The basic science on carbon stocks and flows is available. However, large gaps in the existing measurement methods obscures failure, or fails to incentivize action and the potential for emissions reductions is unknown. Other countries intentions for emissions coverage is currently unknown and extensive use of land for carbon abatement could cause leakage of Australia's agricultural emissions offshore. A key risk is the permanence of ecosystem carbon under a changing climate. Considering its heavy reliance on ecological restoration, these risks and unknowns suggest that Australia's plan is not, or at least not yet, feasible.

Large quantities of 'negative emissions' will be required to meet the 1.5 & DEG;C temperature target under the Paris agreement. As nations consider more ambitious emissions reductions goals, policy makers, carbon market participants and environmental advocates need to estimate the potential scale of nature-based climate solutions (NCS), against the opportunity cost of current land use. In this study we construct a simple linear regression model of the relationship between carbon abatement potential and agricultural profitability, the latter a proxy for opportunity cost, to describe the total set of options for NCS on the Australian continent. Sampling these same two variables at the sites of over 800 land-based offset projects accredited since 2015 shows how the market selected from these abatement options. The model demonstrates that offset projects, under a range of crediting methodologies, were typically selected where the ratio of abatement potential to opportunity cost is maximized. These results, produced from two readily available spatial variables, provide an empirically derived framework for those with an interest in the structure of the long-run supply curve for land-based carbon abatement. This modelling approach could be applied in any geographic region where similar spatial variables for agricultural profitability and abatement potential are available. Key policy insightsWe find a strong positive correlation between the quantity of abatement potential on a land parcel and its potential opportunity cost, the latter represented by agricultural profitability.The lowest cost abatement will be obtained by policies, including market mechanisms, that optimize these two factors rather than prioritizing one over the other.Policies that direct projects to 'marginal' agricultural land may lead to a more costly emissions reduction pathway.Our modelling approach is a key input to the development of a long-run supply curve for land-based abatement, essential to any strategy that relies heavily on negative emissions.Understanding the drivers of land-based abatement projects can help to predict the land use policy impacts of a higher offset requirement.

Background Many fires in north Australian savannas are severe enough to cause canopy scorch, tree death and removal of stags. Better fire management may increase carbon sequestration in trees, perhaps including stags. Aims To describe and analyse dynamics of stags in tropical savannas (600-1000 mm annual rainfall) in relation to fire and better understand their role in biomass sequestration. Methods We monitored marked populations of live and dead trees over 12 years. Statistical models describing influences on stag creation and loss are applied in stag dynamics simulations. Key results Immediately following severe fire, stag biomass increases acutely because many more live trees are killed than stags removed. Between severe fires, stag losses exceed tree deaths, so peaks are quite short. Many 'new' stags are lost (fallen or consumed) quickly. Conclusions Between fires, stags comprise similar to 7.5-8.9% of standing above-ground biomass, more under dry conditions and during recovery from severe fire or other drivers of increased tree mortality. Fire management is unlikely to increase proportions of total woody biomass in stags unless it also reduces live biomass. Implications Reducing frequency of severe fires can increase total carbon sequestration in dry tropical savannas. Prediction uncertainties and management risks around sequestration present daunting challenges for policy-makers and fire management practitioners.

Woody vegetation restoration projects are an important feature of landscape function in Indonesian karst savannas. Understanding the relationship between available moisture and vegetation condition can assist with the planning and implementation of revegetation efforts. Working at vegetation restoration sites in East Nusa Tenggara, Indonesia, we applied a windowed cross-correlation method to mean values of NDVI to examine the lag between moisture input and NDVI response for both rainfall and soil moisture between 1999 and 2018. To test for increasing or decreasing trends in NDVI and rainfall time series, we undertook Mann–Kendall trend analyses. We identified increasing trends in Landsat 7 NDVI at two of four restoration sites, with annual increases in NDVI of 2.7 and 3.74 × 10−4 respectively. We found that rainfall dependent sites had significant Pearson’s correlations with NDVI ranging from 0.52 to 0.71, while NDVI was not correlated with rainfall at shallow groundwater sites. There was a clear negative effect of the very dry period on all sites, and this was less pronounced at shallow groundwater sites. Wet years resulted in a positive response to NDVI across all sites, while the response was lower in very wet years with annual rainfall above 1,200 mm. We found that between 2 and 4 months of antecedent rainfall gave the highest correlation with NDVI, while for soil moisture the closest relationship was found with no lag and 1 month lag. Through this study, we demonstrated the applicability of using NDVI, rainfall, and soil moisture trend analyses to identify groundwater-dependent vegetation patches and monitor the effectiveness of vegetation restoration.

We assembled the first gridded burned area (BA) database of national wildfire data (ONFIRE), a comprehensive and integrated resource for researchers, non-government organisations, and government agencies analysing wildfires in various regions of the Earth. We extracted and harmonised records from different regions and sources using open and reproducible methods, providing data in a common framework for the whole period available (starting from 1950 in Australia, 1959 in Canada, 1985 in Chile, 1980 in Europe, and 1984 in the United States) up to 2021 on a common 1° × 1° grid. The data originate from national agencies (often, ground mapping), thus representing the best local expert knowledge. Key opportunities and limits in using this dataset are discussed as well as possible future expansions of this open-source approach that should be explored. This dataset complements existing gridded BA data based on remote sensing and offers a valuable opportunity to better understand and assess fire regime changes, and their drivers, in these regions. The ONFIRE database can be freely accessed at https://zenodo.org/record/8289245 .

Fire management across Australia's fire-prone 1.2 M km2 northern savannas region has been transformed over the past decade supported by the inception of Australia's national regulated emissions reduction market in 2012. Today, incentivised fire management is undertaken over a quarter of that entire region, providing a range of socio-cultural, environmental, and economic benefits, including for remote Indigenous (Aboriginal and Torres Strait Islander) communities and enterprises. Building on those advances, here we explore the emissions abatement potential for expanding incentivised fire management opportunities to include a contiguous fire-prone region, extending to monsoonal but annually lower (<600 mm) and more variable rainfall conditions, supporting predominantly shrubby spinifex (Triodia) hummock grasslands characteristic of much of Australia's deserts and semi-arid rangelands. Adapting a standard methodological approach applied previously for assessing savanna emissions parameters, we first describe fire regime and associated climatic attributes for a proposed similar to 850,000 km(2) lower rainfall (600-350 mm MAR) focal region. Second, based on regional field assessments of seasonal fuel accumulation, combustion, burnt area patchiness, and accountable methane and nitrous oxide Emission Factor parameters, we find that significant emissions abatement is feasible for regional hummock grasslands. This applies specifically for more frequently burnt sites under higher rainfall conditions if substantial early dry season prescribed fire management is undertaken resulting in marked reduction in late dry season wildfires. The pro-posed Northern Arid Zone (NAZ) focal envelope is substantially under Indigenous land ownership and man-agement, and in addition to reducing emissions impacts associated with recurrent extensive wildfires, development of commercial landscape-scale fire management opportunities would significantly support social, cultural and biodiversity management aspirations as promoted by Indigenous landowners. Combined with existing regulated savanna fire management regions, inclusion of the NAZ under existing legislated abatement methodologies would effectively provide incentivised fire management covering a quarter of Australia's land-mass. This could complement an allied (non-carbon) accredited method valuing combined social, cultural and biodiversity outcomes from enhanced fire management of hummock grasslands. Although the management approach has potential application to other international fire-prone savanna grasslands, caution is required to ensure that such practice does not result in irreversible woody encroachment and undesirable habitat change.

Many studies have compared results from sound recordings and traditional point-count survey observer data when surveying avian communities. None have investigated the use of a moving sound recorder to replicate line-transect surveying. We conducted point-count surveys and line-transect surveys in four urban/peri-urban habitats in Darwin, tropical Australia, with stationary and moving sound recorders, respectively, to assess whether such a combi-nation would result in more bird species being identified than with either technique alone. More bird species were identified using sound recordings than standard observer data. Further, the difference in the number of species identified between the observer and audio from point-count surveys was found to be significant with audio identification being more accurate; however, line-transect surveys showed no significant difference between the two identification methods. Overall, there was no statistical significance between using point-count surveys and line-transect surveys for total species identified. Linear mixed modelling found the interaction between habitat and survey type (point-count vs line-transect) was strongly significant, but not so that between habitat and survey method (sound recording vs human observation). Our results indicate that the integration of bioacoustic and drone technologies with traditional avian surveying techniques adds significant additional identifications when compiling a species list of an area.

Landscape fires, predominantly found in the frequently burning global savannas, are a substantial source of greenhouse gases and aerosols. The impact of these fires on atmospheric composition is partially determined by the chemical breakup of the constituents of the fuel into individual emitted chemical species, which is described by emission factors (EFs). These EFs are known to be dependent on, amongst other things, the type of fuel consumed, the moisture content of the fuel, and the meteorological conditions during the fire, indicating that savanna EFs are temporally and spatially dynamic. Global emission inventories, however, rely on static biome-averaged EFs, which makes them ill-suited for the estimation of regional biomass burning (BB) emissions and for capturing the effects of shifts in fire regimes. In this study we explore the main drivers of EF variability within the savanna biome and assess which geospatial proxies can be used to estimate dynamic EFs for global emission inventories. We made over 4500 bag measurements of CO2, CO, CH4, and N2O EFs using a UAS and also measured fuel parameters and fire-severity proxies during 129 individual fires. The measurements cover a variety of savanna ecosystems under different seasonal conditions sampled over the course of six fire seasons between 2017 and 2022. We complemented our own data with EFs from 85 fires with locations and dates provided in the literature. Based on the locations, dates, and times of the fires we retrieved a variety of fuel, weather, and fire-severity proxies (i.e. possible predictors) using globally available satellite and reanalysis data. We then trained random forest (RF) regressors to estimate EFs for CO2, CO, CH4, and N2O at a spatial resolution of 0.25∘ and a monthly time step. Using these modelled EFs, we calculated their spatiotemporal impact on BB emission estimates over the 2002–2016 period using the Global Fire Emissions Database version 4 with small fires (GFED4s). We found that the most important field indicators for the EFs of CO2, CO, and CH4 were tree cover density, fuel moisture content, and the grass-to-litter ratio. The grass-to-litter ratio and the nitrogen-to-carbon ratio were important indicators for N2O EFs. RF models using satellite observations performed well for the prediction of EF variability in the measured fires with out-of-sample correlation coefficients between 0.80 and 0.99, reducing the error between measured and modelled EFs by 60 %–85 % compared to using the static biome average. Using dynamic EFs, total global savanna emission estimates for 2002–2016 were 1.8 % higher for CO, while CO2, CH4, and N2O emissions were, respectively, 0.2 %, 5 %, and 18 % lower compared to GFED4s. On a regional scale we found a spatial redistribution compared to GFED4s with higher CO, CH4, and N2O EFs in mesic regions and lower ones in xeric regions. Over the course of the fire season, drying resulted in gradually lower EFs of these species. Relatively speaking, the trend was stronger in open savannas than in woodlands, where towards the end of the fire season they increased again. Contrary to the minor impact on annual average savanna fire emissions, the model predicts localized deviations from static averages of the EFs of CO, CH4, and N2O exceeding 60 % under seasonal conditions.

Tropical savannas are characterized by high primary productivity and high fire frequency, such that much of the carbon captured by vegetation is rapidly returned to the atmosphere. Hence, there have been suggestions that management-driven reductions in savanna fire frequency and/or severity could significantly reduce greenhouse gas emissions and sequester carbon in tree biomass. However, a key knowledge gap is the extent to which savanna tree biomass will respond to modest shifts in fire regimes due to plausible, large-scale management interventions. Here, we: (1) characterize relationships between the frequency and severity of fires and key demographic rates of savanna trees, based on long-term observations in vegetation monitoring plots across northern Australia; (2) use these relationships to develop a process-explicit demographic model describing the effects of fire on savanna tree populations; and (3) use the demographic model to address the question: to what extent is it feasible, through the strategic application of prescribed burning, to increase tree biomass in Australian tropical savannas? Our long-term tree monitoring dataset included observations of 12,344 tagged trees in 236 plots, monitored for between 3 and 24 years. Analysis of this dataset showed that frequent high-severity fires significantly reduced savanna tree recruitment, survival, and growth. Our demographic model suggested that: (1) despite the negative effects of frequent high-severity fires on demographic rates, savanna tree biomass appears to be suppressed by only a relatively small amount by contemporary fire regimes, characterized by a mix of low- to high-severity fires; and (2) plausible, management-driven reductions in the frequency of high-severity fires are likely to lead to increases in tree biomass of about 11.0 t DM ha(-1) (95% CI: -1.2-20.8) over a century. Accounting for this increase in carbon storage could generate significant carbon credits, worth, on average, three times those generated annually by current greenhouse gas (methane and nitrous oxide) abatement projects, and has the potential to significantly increase the economic viability of fire/carbon projects, thereby promoting ecologically sustainable management of tropical savannas in Australia and elsewhere. This growing industry has the potential to bring much-needed economic activity to savanna landscapes, without compromising important natural and cultural values.

A global trend of increasing tree cover in savannas has been observed and ascribed to a range of possible causes, including CO2 levels, changing rainfall and fire frequency. We tested these explanations in the Australian tropical savanna, taking 96 savanna ‘cool burning’ projects from Australia’s emissions offset scheme as case studies. We obtained readings of tree cover and explanatory variables from published remote sensing or spatial data sources. These were analysed using time-series linear regression to obtain coefficients for the influence of severe fire occurrence, annual rainfall and prior percentage tree cover. Although statistically significant coefficients for the key variables were found in only half (severe fire) or one quarter (rainfall) of the individual project models, when comparing all the model coefficients across the rainfall gradient, ecologically coherent explanations emerge. No residual trend was observed, suggesting rising CO2 levels have not influenced tree cover over the study period. Our approach models tree cover change by separating ecological drivers from human-controlled factors such as fire management. This is an essential design feature of national emissions inventories and emissions offsets programs, where crediting must be additional to the expected baseline, and arise from human activity.

Tropical savannas and grasslands are the most frequently burned biome in the world, and fire has an important role in sustaining ecosystem processes. Modern management of fires in savannas has roots in traditions stretching back centuries, and nowadays earth observation data is incorporated extensively in fire management practices. In tropical savannas in particular strongly seasonal monsoonal climates allow relatively low severity prescribed burning in the early part of the dry season (EDS) with the goal of preventing more destructive late dry season (LDS) fires. In many regional contexts it is common that a specific, fixed date is used officially to indicate when the window of safe burning has expired and the EDS transitions to the LDS, based on the experience of local or regional fire management authorities. This approach, while practical, neglects inter-annual variability in meteorological conditions and timing of onset of more dangerous fire weather. In this study, we pro-pose a remote sensing-based method for determining when this EDS window expires for five savanna-dominated continental-scale regions. By taking ad- vantage of the fact that conditions allowing night-time burning occur later in the dry season, we use day and night-time active fire detections from the MODerate Resolution Imaging Spectroradiometer (MODIS) instruments to set a flexible date of transition between the EDS and LDS. The vast majority of tropical savannas have very variable (std. dev. ≈ 20–40 days) transition dates, though this is somewhat modulated by fire frequency. Fuel connectivity rather than fuel condition appears to be a strong driving factor behind this variability. We find that especially national parks and protected areas have a high proportion of potentially more severe burning in the LDS, though areas with well-established EDS burning programmes are reducing this impact.

Roughly half of global fire emissions originate from savannas, and emission factors (EF) are used to quantify the amount of trace gases and aerosols emitted per unit dry matter burned. It is well known that these EFs vary substantially even within a single biome but so far quantifying their dynamics has been hampered by a lack of EF measurements. Therefore, global emission inventories currently use a static averaged EF for the entire savanna biome. To increase the spatiotemporal coverage of EF measurements, we collected over 4500 EF bag measurements of CO2, CO, CH4 and N2O using an unmanned aerial system (UAS) and measured fuel parameters and fire severity proxies during 129 individual landscape fires. These measurements spanned various widespread savanna ecosystems in Africa, South America and Australia, with early and late dry season campaigns. We trained random forest (RF) regressors to estimate daily dynamic EFs for CO2, CO, CH4 and N2O at 500×500-meter resolution based on satellite and reanalysis data. The RF models reduced the difference between measured and modelled EFs by 60-85% compared to static biome averages. The introduction of EF dynamics resulted in a spatial redistribution of CO, CH4 and N2O emissions compared to the Global Fire Emissions Database version 4 (GFED4s) with higher emissions in higher rainfall savanna regions. While the impact from using dynamic EFs on the global annual emission estimates from savannas was relatively modest (+2% CO, -5% CH4 and -18% N2O), the impact on local EFs may exceed 60% under dry seasonal conditions.

Abstract The interaction between environmental stressors may be a greater threat to biota than any individual ecological threat on its own. Land‐use change and inappropriate fire regimes are known to pose great challenges to biodiversity conservation worldwide. Despite much research being conducted into their singular impacts on ecosystems, very few have investigated how their interaction may be affecting the biota of a region. We used data from surveys in 1998/2000 and 2019/2020 to compare the feeding guild assemblages of bird communities in different habitats within the greater Darwin region. By compiling two sets of spatial data, land‐use change, and fire history mapping, we were able to investigate their interaction and impact on the avian assemblages in the Darwin urban area. Using Generalized Linear Mixed Models (GLMM) we found that an increase in urbanization significantly affected fire occurrence across study sites. Furthermore, we found that the interaction between land‐use change and fire regimes had a significant effect on species that primarily feed on fruit. We conclude that while an increase in urbanization did not directly affect the avian assemblages, the impact of land‐use change on the fire regimes indirectly impacted urban bird community structures.