Early Burning Research Articles

Balancing livestock production and environmental outcomes in northern Australia’s tropical savanna under global change

Abstract Livestock production is an integral part of the global food system and the livelihoods of local people, but it also raises questions of environmental sustainability due to issues such as greenhouse gas (GHG) emissions, biodiversity decline, land degradation, and water use. Further challenges to extensive livestock systems may arise from changes in climate and the global economy (particularly variation in prices for livestock and carbon). However, significant potential exists for both mitigating these impacts and adapting to change via altering stocking rates, managing fire, and supplementing cattle diets to reduce methane emissions. We developed an integrated, spatio-temporal modelling approach to assess the effectiveness of these options for land management in northern Australia’s tropical savanna under different global change scenarios. Performance was measured against a range of sustainability indicators, including environmental (GHG emissions, biodiversity, water intake, and land condition) and agricultural (profit, beef production) outcomes. Our model shows that maintaining historical stocking rates is not environmentally sustainable due to the accelerated land degradation exacerbated by a changing climate. However, planned early dry season burning substantially reduced emissions, and in our simulations was profitable under all global change scenarios that included a carbon price. Overall, the balance between production and environmental outcomes could be improved by stocking below modelled carrying capacity and implementing fire management. This management scenario was the most profitable (more than double the profit from maintaining historical stocking rates), prevented land degradation, and reduced GHG emissions by 23%. By integrating the cumulative impacts of climate change, external economic drivers, and management actions across a range of sustainability indicators, we show that the future of rangelands in Australia’s savannas has the potential to balance livestock production and environmental outcomes.

Uncertainties from biomass burning aerosols in air quality models obscure public health impacts in Southeast Asia

Abstract. Models suggest that biomass burning causes thousands of premature deaths annually in Southeast Asia due to excessive exposure to particulate matter (PM) in smoke. However, measurements of surface air quality are sparse across the region, and consequently estimates for the public health impacts of seasonal biomass burning, are not well constrained. We use the nested GEOS-Chem model of chemistry and transport (horizontal resolution of 0.25°×0.3125°) to simulate atmospheric composition over Southeast Asia during the peak burning months of March and September in the moderate burning year of 2014. Model simulations with GEOS-Chem indicate that regional surface levels of PM2.5 (fine particulate matter with a diameter ≤2.5 µm) greatly exceed World Health Organization guidelines during the burning seasons, resulting in up to 10 000 premature deaths in a single month. However, the model substantially underestimates the regional aerosol burden compared to satellite observations of aerosol optical depth (AOD) (20 %–52 %) and ground-based observations of PM (up to 54 %), especially during the early burning season in March. We investigate potential uncertainties limiting the model representation of biomass burning aerosols and develop sensitivity simulations that improve model–measurement agreement in March (to within 31 %) and increase the estimated number of PM2.5-related premature deaths that month by almost half. Our modifications have a much smaller impact on the same metrics for September, but we find that this is due to canceling errors in the model. Compared to PM2.5 simulated directly with GEOS-Chem, PM2.5 derived from satellite AOD is less sensitive to model uncertainties and may provide a more accurate foundation for public health calculations in the short term, but continued investigation of uncertainties is still needed so that model analysis can be applied to support mitigation efforts. Further reduction of uncertainties can be achieved with the deployment of more aerosol measurements across Southeast Asia.

Climate change must be factored into savanna carbon- management projects to avoid maladaptation: the case of worsening air pollution in western Top End of the Northern Territory, Australia

Savanna fires are a major source of greenhouse gas (GHG) and particulate pollution globally. Since mid-2006, an Australian Government carbon offset program has incentivised Northern Territory land managers to undertake early dry-season savanna burning with the aim of reducing late dry-season wildfires and associated GHG emissions. The focus of this study is addressing concern that savanna burning carbon abatement projects are causing worsening air pollution in the city of Darwin. Reconstructed concentrations of daily particulate matter of <2.5 μm (PM2.5) since the 1960s showed since 2000s a worsening in PM2.5 in the early dry season (May, June, July), some improvement in the late dry season (August, September, October) with little overall difference for the whole dry season. Remote-sensing PM2.5 estimates in Darwin were correlated with region-wide PM2.5 estimates during the early dry season. Remote-sensing analysis of area burned and intensity of fires since 2002 showed that savanna carbon projects have shifted burning to the early dry season and caused increases in fire intensity compared with non-project areas. Increased fire intensity appears to follow sharply declining fuel moisture, as well as management effects on carbon project areas, which have possibly undermined the efficacy of savanna burning projects in reducing GHG emissions. More thorough evaluation of underlying assumption of savanna burning carbon abatement in Australia and elsewhere in the world is required to avoid maladaptation, such as over-crediting, smoke pollution, and other environmental harms.

Comparative analysis of tick burden, diversity, and distribution in intensively managed wildlife estates with and without prescribed burning

The connection between ticks and zoonotic diseases in Zambia remains unclear due to limited data on tick distribution in private game reserves. This study examines tick control in three ex-situ game reserves across different agro-ecological regions, Lanagani game ranch in the Chibombo district, Chaminuka game ranch in the Lusaka district, and Choma game ranch in the Choma district. The current study evaluated the burden and diversity of ticks across three different management systems concerning the use of fire as a tick control and management tool. A descriptive cross-sectional study collected 267 ticks from 36 transects across three game ranches in Central, Lusaka, and Southern provinces. These ticks were morphologically identified using the existing taxonomic keys and Olympus DF Plapo 1×4 SN5G 08128 stereomicroscope at the University of Zambia, School of Veterinary Medicine, parasitology laboratory. The Analysis of Variance (ANOVA) was used to compare means between categories and correlation coefficient to determine the strength of the relationship. The collected species included 11 Rhipicephalus species, n=6, (Rhipicephalus appendiculatus, Rhipicephalus evertsi, Rhipicephalus microplus, Rhipicephalus decoloratus, Rhipicephalus sanguineus, Rhipicephalus pulcherus, Rhipicephalus zambeziensis); Amblyomma species n=2, (Amblyomma variagatum, Amblyomma poposum), and Hyalomma species n=2 (Hyalomma Rufipes and Hyalomma truncatum). The most common species were R. evertsi (19.4 %), Amblyomma variagatum 14%, Hyalomma truncatum 11%. Significantly higher (p < 0.05) species diversity and burden were observed in the no-burn management system, whilst no significant differences (p > 0.05) were observed between late and early burning systems. These findings have unveiled, for the first time in Zambia, that employing fire as a management tool substantially reduces both tick diversity and burden in enclosed ex-situ conservancy areas. Regular prescribed burning, regardless of the burning regime, was found to remarkably reduce tick populations in game ranches, particularly in the early burning management system. These findings hold promising implications for ecological public health. Considering this, fire as a management tool effectively reduces tick diversity and burden in closed ex-situ conservancy areas. These findings have far-reaching policy implications when it comes to tick control systems that a government may wish to implement.

Division of the tropical savanna fire season into early and late dry season burning using MODIS active fires

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.

Influence of Fire on Floristic Diversity and Herbaceous Production in the Ollombo Savannahs in the Republic of Congo

The Loudetia simplex (Nees) C.E. Hubb. savanna and the Hyparrhenia diplandra (Hack.) Stapf savanna are the main savannas in the Ollombo area of the Republic of Congo. The functioning of these savannas is influenced by the different types of fire. The aim of this study is to assess the influence of fire on the floristic diversity and herbaceous production of the savannahs in the Ollombo area. The floristic inventory and phytomass measurements were carried out at the peak of vegetation before the fires and at 2 and 10 months after the fires. The floristic inventory was carried out using the aligned quadrat points method. The data from this inventory were used to calculate diversity indices, including the Shannon-Weaver index (H'). Above-ground herbaceous phytomass was assessed using the harvesting method. The results show that floristic diversity and herbaceous above-ground phytomass vary from one type of fire to another and from one type of savannah to another. In the Loudetia simplex (Nees) C.E. Hubb. savannah, seasonal fire (H'=2.69) and late fire (H'=2.43) appear to favour floristic diversity at 2 and 10 months after burning, respectively. In the Hyparrhenia diplandra (Hack.) Stapf savannah, on the other hand, only early fire seems to favour floristic diversity two months (H'=2.7) and 10 months (H'=2.4) after burning. In terms of herbaceous above-ground phytomass, seasonal fire (0.82 ±0.07 t DM/ha) and early fire (6.49 ±1.06 t DM/ha) appear to increase herbaceous production at 2 and 10 months after burning, respectively, in the Loudetia simplex Nees C.E. Hubb. savannah. On the other hand, late burning (0.88 ±0.07 t DM/ha) and early burning (6.98 ±1.01 t DM/ha) appear to increase herbaceous production at 2 and 10 months respectively in the savannah with Hyparrhenia diplandra (Hack.) Stapf. These results could serve as a scientific basis for the sustainable management of pastures by fire and as a benchmark for future studies.

Fire seasonality plays a limited role in the reproduction of Anacardium humile A. St.-Hil. in a tropical savanna.

Anthropogenic fires are an increasing threat to tropical savannas and their plant populations. In the Brazilian Cerrado, human-made fires at the end of the dry season are replacing natural fires at the beginning of the dry season. Critically, these late burns occur under more intense climate variables. Here, we aimed to understand the potential role of fire seasonality on individuals of Anacardium humile, a widespread Cerrado species of cultural and economic importance. We conducted two prescribed burnings, one at the beginning of the dry season (early burning) and one at the end of the dry season (late burning) when climate variables were remarkably different. We assessed the reproductive responses of A. humile individuals over 4 years and compared individuals from the fire treatments with those from an unburned area (control). The reproductive phenology of A. humile varied over time and was influenced by climate variables. The seasons of different burning had similar impacts on the reproductive phenology of A. humile, and this impact lasted for at least 4 years. While A. humile populations do not depend on fire for reproduction, they produced more flowers and fruits for up to 2 years with the fire treatments. We provide empirical evidence of the role of climate variables on the phenology of A.humile and demonstrate the importance of considering the role of time after fire events. The similar responses of A. humile to fire seasonality show that Cerrado fire management can be more complex than previously thought.

What burned the forest? Wildfires, climate change and human activity in the Mesolithic – Neolithic transition in SE Iberian Peninsula

Climate variability such as higher or lower temperatures, changing precipitation patterns, shifts in plant communities and other climate-related changes have particularly affected areas with Mediterranean-type climates. A multi-proxy analysis including pollen, sedimentary charcoal, mineralogy and Summed Probability Distributions (SPD) of archaeological 14C dates, allowed the reconstruction of landscape change, geomorphological evolution and fire history at the Laguna de Villena, in the southeastern Iberian Peninsula, during the Mesolithic-Neolithic transition. The Villena paleolake was sensitive to Early Holocene and Middle Holocene regional climatic variability that included several arid phases (around 8.2 ka cal BP, 6.8 ka cal BP and 5.9 ka cal BP) according to geochemical and pollen data. During this period, landscape dynamics show the degradation of oak forests and expansion of pyrophytic pine forests and shrublands, as well as open spaces predominated by grasses. The charcoal record shows a decreasing trend of biomass burned from 8.5 ka cal BP onwards, although fire peaks occurred recurrently during the Early and Middle Holocene. The most intense phase of fire activity was experienced in the last millennia of the Early Holocene, with five fire episodes from 9.1 to 8.4 ka cal BP, coinciding with a phase of higher archaeological evidence in the area. A decrease in archaeological evidence coincides with a gap in fire episodes during the Early Holocene-Middle Holocene transition, suggesting an effect of the abrupt 8.2 ka cal BP event on human activity and on landscape dynamics. After 8.0 ka cal BP, lowerer biomass burned is explained by the configuration of a more open landscape due to the combination of climate (increasing aridity) and increasing human activities in the region. The mineralogical and palynological data highlighted the interaction between human activities, climate and fire dynamics. The sedimentary charcoal record evidenced how most of the fire peaks did not occur in the context of dry episodes, as often assumed, deriving on an anthropogenic explanation related to Early and Late Mesolithic burning practices during a phase of higher archaeological evidence in the Villena paleolake surroundings. Afterwards, combined agropastoral activities from the Early Neolithic onwards and increasing aridity during the Middle Holocene maintained the forest clearances, in the context of fire episodes characterised by decreased biomass burned. This study shows how Middle Holocene palaeoecological records reflect complex histories blending climate and anthropogenic processes that derived in major landscape changes explaining the origin of current landscapes.

Vegetation and fire history of Bwabwata National Park, Namibia

The relationships between woody vegetation cover and fire, climate, herbivory, and human activities in African savanna ecosystems are complex. Fire has been managed by humans for thousands of years, but post 1800, fire suppression was implemented in many areas. The impact of these policies are largely unknown, due to a lack of long-term records extending from before, during and after their implementation.Here, we present two ∼1000-year pollen, dung fungal spore and charcoal records from a savanna ecosystem in Bwabwata National Park, in north-east Namibia, an area that had a fire suppression policy in place from 1888 to 2005. Proxies from both cores (Jackalberry and Mukolo) show similar trends. Both records show higher tree abundance during a wetter period early in the record. No evidence of fire suppression or enhanced tree recruitment is seen in the charcoal and pollen data from the period post 1888. The results imply that the policy of fire suppression was ineffective, and did not lead to noticeable decreases in fire and associated enhancement of tree recruitment. The results are consistent with the knowledge that fire is an integral component of this ecosystem, and that fire occurrence in savanna ecosystems is more closely linked to climate than management. Therefore, fire management should adapt to rainfall variability as well as integrating customs of early dry season burning that benefit both biodiversity and livelihoods. Our results show how long-term datasets can be used to assess the impacts of fire suppression and inform present-day management decisions.

Immediate postoperative topical lidocaine gel for the treatment of eye pain following corneal abrasion in descemet membrane endothelial keratoplasty (DMEK) under general anaesthesia: a pilot retrospective analysis

BackgroundPatients undergoing corneal abrasion as part of Descemet membrane endothelial keratoplasty (DMEK) under general anesthesia suffer from early burning pain postoperatively. This pain appears to be poorly treatable with systemic analgesics. This study aims to evaluate postoperative pain management using topical lidocaine gel after DMEK with iatrogenic corneal abrasion.MethodsRetrospective analysis of 28 consecutive patients undergoing DMEK with corneal abrasion from October 19, 2021, to November 12, 2021, at a German university hospital. Patients during week 1 and 2 received peri-operative standard pain treatment (cohort S) and additional local lidocaine gel during week 3 and 4 immediately postoperatively (cohort L).Results13 patients were included in cohort S and 15 patients in cohort L. At awakening all patients (100%) in cohort S reported burning pain, and six of 15 patients (40%) in cohort L reported burning pain. Burning pain scores were significantly lower in cohort L (p < 0.001 at awakening, p < 0.001 at 10 min, p < 0.001 at 20 min, p < 0.001 at 30 min, p = 0.007 at 40 min after awakening, and p < 0.001 at leaving recovery room). No significant differences between cohort S and cohort L were detected concerning surgical outcome during 1-month-follow-up (p = 0.901 for best corrected visual acuity).ConclusionPatients undergoing DMEK with corneal abrasion suffer significant pain in the recovery room. A single dose of topic lidocaine gel reduces the early postoperative burning pain sufficiently and does not affect the surgical outcome.

Use of Remotely Piloted Aircraft System Multispectral Data to Evaluate the Effects of Prescribed Burnings on Three Macrohabitats of Pantanal, Brazil

The controlled use of fires to reduce combustible materials in prescribed burning helps to prevent the occurrence of forest fires. In recent decades, these fires have mainly been caused by anthropogenic activities. The study area is located in the Pantanal biome. In 2020, the greatest drought in 60 years happened in the Pantanal. The fire affected almost one third of the biome. The objective of this study is to evaluate the effect of prescribed burnings carried out in 2021 on three macrohabitats (M1: natural grassland flooded with a proliferation of Combretum spp., M2: natural grassland of seasonal swamps, and M3: natural grassland flooded with a proliferation of Vochysia divergens) inside the SESC Pantanal Private Natural Heritage Reserve. Multispectral and thermal data analyses were conducted with remotely piloted aircraft systems in 1 ha plots in three periods of the dry season with early, mid, and late burning. The land use and land cover classification indicate that the predominant vegetation type in these areas is seasonally flooded grassland, with percentages above 73%, except in zone three, which has a more diverse composition and structure, with the presence of arboreal specimens of V. divergem Pohl. The pattern of the thermal range showed differentiation pre- and post-burning. The burned area index indicated that fire was more efficient in the first two macrohabitats because they are natural grasslands, reducing the grass species in the burnings. Early and mid prescribed burnings are a good option to reduce the continuous accumulation of dry forest biomass fuel material and help to promote landscape heterogeneity. The use of multispectral sensor data with high spatial/spectral resolution can show the effects of fires, using highly detailed scales for technical decision making.

The Effects of Prescribed Dry Season Burning on Woody Species Composition, Mole National Park, Ghana

Fire use in protected savannas of Africa is a common practice. Fires in these savannas create many environmental benefits, such as reducing grass, brush and trees that can fuel large and severe wildfires and improving wildlife habitat. However, wrong timing of fire can threaten plants, animals and habitats. This study investigated the effects of time of burning on woody plant composition, diversity and density in the Mole National Park, Ghana. A total of twelve 300 m2 plots were systematically sampled in a 200 m × 200 m treatment plot established by Park Management each for early burn, late burn and no-burn plots. Twenty-seven different woody species belonging to fourteen families were recorded in all the treatments. Most of the species identified belonged to the families Fabaceae and Combretaceae. Vitellaria paradoxa (Shea), Terminalia avicennioides, Combretum adenogonium and Combretum molle were the most common and abundant in all treatments. A TWINSPAN on sites and species revealed four species groups based on affinity to burning time. A follow-up DCA showed a strong association between burning time and species composition, with the first two axes explaining 65% of variation. The late burn and no-burn treatments recorded the lowest diversity amongst the three treatments. Stem density was highest in no-burn treatment which had lowest species richness and diversity compared to early and late burn treatments. Early burn treatment had the highest diversity and the lowest density of woody species. The study revealed that the different times of prescribed burning influenced vegetation differently. Prescribed early dry season burning could contribute to the management of indigenous woody species in protected fire-prone savannas, because it can promote the diversity of species, as found in the Mole National Park in the Guinea savanna of Ghana.

Flowering and fruiting show phenological complementarity in both trees and non-trees in mosaic-burnt floodable savanna

The homogenization of fire regimes in a landscape may imply a temporal reduction in the availability of resources, such as flowers and fruits, which affect the fauna, as well as ecosystem services. We hypothesized that maintaining mosaic burning regimes, and thereby pyrodiversity, can diversify phenological patterns, ensuring year-round availability of flowers and fruits. Here we monitored open grassy tropical savanna phenology under different historical fire frequencies and fire seasons in a highly heterogeneous landscape in an Indigenous Territory in Brazil. We evaluated phenological patterns of tree and non-tree plants through monthly surveys over three years. These two life forms responded differently to climate and photoperiod variables and to fire. Different fire regimes led to a continuous availability of flowers and fruits, due to the complementarity between tree and non-tree phenologies. Late-season fires are supposed to be more devastating, but we did not detect a significant reduction in flower and fruit production, especially under moderate fire frequency. However, late burning in patches under high frequency resulted in a low availability of ripe fruits in trees. The fruiting of non-tree plants in patches under low fire frequency and early burning ensure ripe fruit, when there are practically no trees fruiting in the entire landscape. We conclude that maintaining a seasonal fire mosaic should be prioritized over historical fire regimes, which lead to homogenization. Fire management is best conducted between the end of the rainy season and the beginning of the dry season, when the risk of burning fertile plants is lower.

Gastric sensorimotor function and its clinical measurement.

Gastroduodenal symptoms are highly prevalent, with underlying sensorimotor dysfunction contributing in many patients. Common symptoms include early satiation, postprandial fullness, epigastric bloating, pain or burning, nausea and vomiting, which collectively affect over 7% of adults. However, the clinical evaluation of these symptoms remains challenging, with current tests of gastric function remaining limited in their ability or availability to separate specific patient subgroups or guide-targeted care. In the current edition of Neurogastroenterology & Motility, Silver et al. present new data showing correlations between patterns of intragastric meal distribution and symptom profiles in a large series of patients undergoing gastric emptying scintigraphy. Studies of this type are important, as they motivate understanding beyond existing disease labels, and orient focus toward deeper mechanistic profiling. This brief review provides an overview of gastric sensorimotor function and profiles several current and emerging methods of clinical evaluation. Perspectives are provided on accommodation testing, gastric emptying, measuring gastric myoelectrical activity including new approaches, and antroduodenal manometry. Although gastric physiology is complex, recent progress has been encouraging, with the heterogenous pathophysiology of gastric symptoms continuing to be unraveled, and new techniques for evaluating gastric function and symptoms emerging. Ongoing progress will now depend on continuing to accurately profile the underlying mechanisms of gastroduodenal disorders to identify specific disease phenotypes that inform care.

Smoke pollution must be part of the savanna fire management equation: A case study from Darwin, Australia

Savanna fire management is a topic of global debate, with early dry season burning promoted as a large-scale emissions reduction opportunity. To date, discussions have centred on carbon abatement efficacy, biodiversity and cultural benefits and/or risks. Here we use a case study of Darwin, Australia to highlight smoke pollution as another critical consideration. Smoke pollution from savanna fires is a major public health issue, yet absent so far from discussions of program design. Here, we assess the likely impacts of increased early dry season burning on smoke pollution in Darwin between 2004 and 2019, spanning the introduction and expansion of carbon abatement programs. We found increased smoke pollution in the early dry season but little change in the late dry season, contributing to a net annual increase in air quality standard exceedances. Geospatial analysis suggests this relates to increased burning in the path of early dry season trade winds. This study highlights the complex health trade-offs involved with any large-scale prescribed burning, including for carbon abatement.

Role of alkali chloride on formation of ultrafine particulate matter during combustion of typical food waste

Particulate matter (PM) emission from municipal solid waste (MSW) incineration poses a threat to both the environment and human health. The current understanding of PM from MSW incineration is limited to its emission characteristics, while the formation mechanism in flame is far from clear. In this work, a flat-flame burner and a thermophoretic sampling system were used to investigate the formation and evolution of nanoparticles during the combustion of typical food waste. The diameter, morphology, and chemical composition of particles sampled at different burning stages and positions were analyzed. We found that the formation of nanoparticles is governed by the sooting process and the gas-to-solid conversion of mineral vapors in the early burning stage, while in the late stage, cubic nanoparticles are observed on the surface of the fuel pellet and are carried into flame by the gas flow, leading to a remarkable increase in the size of nanoparticles sampled at different heights. Based on the element mapping, the EDS spectra, and a time scale analysis, we prove that the main component of these cubic particles is KCl. Moreover, adding NaCl with the mass ratio 1.3%∼5.1% into the fuel pellet can promote the formation of cubic KCl particles and increase the particle size at all sampling points, while further increasing the NaCl mass ratio to 8.8% leads to the formation of low-temperature KCl/NaCl eutectic and reduces the size of nanoparticles. The gas-carrying of alkali chloride particles reported in the current work helps to form a more complete picture of PM formation from the combustion of solid fuels.

Tipping the scales: how fire controls the balance among functional groups in Angolan grasslands

Fire plays an important role in the ecology of tropical grasslands globally. However, detailed studies comparing the response of plant functional groups to fire seasonality, and thus phenological timing, are scarce from humid Afrotropical grasslands. Such information, however, is crucial for understanding what keeps the grasslands open and for enabling evidence-based management, and conservation. We initiated an experiment in frost- and fire-prone Angolan geoxyle grasslands in 2017, investigating the effect of different timing of fires on cover and diversity of trees, grasses, geoxyles and herbs. We installed permanent, randomised plots with fire exclusion, annual early and late dry-season burning, representing the local burning practices. Functional plant groups reacted differently to the treatments, becoming apparent at species level and their performance metrics. After three years, grass species benefitted from late and no burning, and herbs from late burning, whereas geoxyles thrived under early burning. Tree growth was suppressed under late burning, and did not increase with fire exclusion. Species richness and diversity was higher in burnt than in unburnt plots. Seasonal timing of fire tips the scales between geoxyles and grasses. The extraordinary plant diversity of Angolan geoxyle grasslands is a result of pyrodiversity and frost, keeping the grasslands open even in absence of fire.

Prescribed fire reduces insect infestation in Karuk and Yurok acorn resource systems

Prescribed fire is used extensively as a management tool in fire-adapted landscapes of the American West to maintain ecosystem structure and function while reducing wildfire risk. Seasonally specific prescribed fire is used by many Indigenous groups to increase the quality and quantity of cultural resources and promote desired patterns of habitat diversity. Traditionally, the Karuk and Yurok Tribes of California applied fire in tanoak (Notholithocarpus densiflorus, Fagaceae) acorn gathering areas during the fall to reduce infestation in acorns by larvae of the filbertworm (Cydia latiferreana, Tortricidae) and filbert weevil (Curculio occidentalis, Curculionidae). It has become increasingly difficult to select culturally appropriate times in which to apply fire as a resource management tool due to changing environmental conditions and associated political considerations. To assess the effect of non-traditional management on tribal acorn resource systems, we investigated the effects of early summer burning on rates of larval infestation in tanoak acorns. We also studied how competing frugivores affected the availability of edible acorns to human consumers. We found that non-traditional early summer prescribed fire significantly reduced rates of larval infestation during the burn year (36.7%) but no difference between treatments was detected one year-post fire. Selective vertebrate frugivory significantly reduced the density of edible acorns by 39%. Our results highlight the importance of seasonally-specific prescribed fire in managing Karuk and Yurok resource systems and supporting tribal eco-cultural revitalization.

Transforming fire management in northern Australia through successful implementation of savanna burning emissions reductions projects

Savannas are the most fire-prone of Earth's biomes and currently account for most global burned area and associated carbon emissions. In Australia, over recent decades substantial development of savanna burning emissions accounting methods has been undertaken to incentivise more conservative savanna fire management and reduce the extent and severity of late dry season wildfires. Since inception of Australia's formal regulated savanna burning market in 2012, today 25% of the 1.2M km2 fire-prone northern savanna region is managed under such arrangements. Although savanna burning projects generate significant emissions reductions and associated financial benefits especially for Indigenous landowners, various biodiversity conservation considerations, including fine-scale management requirements for conservation of fire-vulnerable taxa, remain contentious. For the entire savanna burning region, here we compare outcomes achieved at ‘with-project’ vs ‘non-project’ sites over the period 2000–19, with respect to explicit ecologically defined fire regime metrics, and assembled fire history and spatial mapping coverages. We find that there has been little significant fire regime change at non-project sites, whereas, at with-project sites under all land uses, from 2013 there has been significant reduction in late season wildfire, increase in prescribed early season mitigation burning and patchiness metrics, and seasonally variable changes in extent of unburnt (>2, >5 years) habitat. Despite these achievements, it is acknowledged that savanna burning projects do not provide a fire management panacea for a variety of key regional conservation, production, and cultural management issues. Rather, savanna burning projects can provide an effective operational funded framework to assist with delivering various landscape-scale management objectives. With these caveats in mind, significant potential exists for implementing incentivised fire management approaches in other fire-prone international savanna settings.

The neutrino emission from thermal processes in very massive stars in the local universe

ABSTRACT We present a new overview of the life of very massive stars (VMS) in terms of neutrino emission from thermal processes: pair annihilation, plasmon decay, photoneutrino process, bremsstrahlung, and recombination processes in burning stages of selected VMS models. We use the realistic conditions of temperature, density, electron fraction, and nuclear isotropic composition of the VMS. Results are presented for a set of progenitor stars with mass of 150, 200, and 300 M⊙Z = 0.002 and 500 M⊙Z = 0.006 rotating models which are expected to explode as a pair instability supernova at the end of their life except the 300 M⊙ would end up as a black hole. It is found that for VMS, thermal neutrino emission occurs as early as towards the end of hydrogen burning stage due to the high initial temperature and density of these VMS. We calculate the total neutrino emissivity, Qν and luminosity, Lν using the structure profile of each burning stages of the models and observed the contribution of photoneutrino at early burning stages (H and He) and pair annihilation at the advanced stages. Pair annihilation and photoneutrino processes are the most dominant neutrino energy loss mechanisms throughout the evolutionary track of the VMS. At the O-burning stage, the neutrino luminosity ∼1047−48 erg s−1 depending on their initial mass and metallicity are slightly higher than the neutrino luminosity from massive stars. This could shed light on the possibility of using detection of neutrinos to locate the candidates for pair instability supernova in our local universe.