Efficacy of permanent firebreaks and aerial prescribed burning in western Arnhem Land, Northern Territory, Australia

2007 ◽  
Vol 16 (3) ◽  
pp. 295 ◽  
Author(s):  
Owen F. Price ◽  
Andrew C. Edwards ◽  
Jeremy Russell-Smith
Keyword(s):  
Prescribed Burning ◽  
Fire Management ◽  
Fire Frequency ◽  
Northern Territory ◽  
Dry Season ◽  
Stream Order ◽  
Arnhem Land ◽  
Linear Modelling ◽  
Populated Region ◽  
Generalised Linear Modelling

We investigated the efficacy of firebreaks in the prevention of wildfires in the Arnhem Land Plateau, a vast, rugged and sparsely populated region with high biodiversity value and frequent wildfires. A total of 623 events where a fire met a permanent firebreak (cliffs, stream order, tracks and roads) in different fire seasons were compiled. Cliffs were more effective than streams at stopping fires, which were more effective than roads. Larger streams were more effective than small ones. The largest streams stop 75% of early dry season fires, but there are no firebreak types with more than 50% likelihood of stopping a late dry season fire. Geographic Information System (GIS) surfaces of the relative density of the three firebreak features in the landscape were randomly sampled and compared with the total number of fires and late dry season fires using generalised linear modelling. Several of the density variables were weakly but significantly related to fire frequency, and it appears that late dry season fires are influenced by features at a larger scale (16-km radius) than total fires (4 km). The Aerial Prescribed Burning program for 2004 was studied to identify how effective it was at stopping subsequent wildfires by dividing ignition lines into 137 5-km sections. Only 20% of sections achieved a 100% burn and where gaps occurred, a subsequent fire was 88% likely to penetrate the line. Firebreaks are not certain instruments for fire management in this area.

Delivering effective savanna fire management for defined biodiversity conservation outcomes: an Arnhem Land case study

2020 ◽  
Vol 29 (5) ◽  
pp. 386 ◽  
Author(s):  
Jay Evans ◽  
Jeremy Russell-Smith
Keyword(s):  
Prescribed Burning ◽  
Fire Management ◽  
Fire Regime ◽  
Dry Season ◽  
Prescribed Burns ◽  
Active Fire ◽  
Arnhem Land ◽  
Ecological Threshold ◽  
History Of ◽  
In Fire

Given the recent history of frequent and extensive late dry season wildfire in Australia’s fire-prone northern savannas, regional conservation-based fire management programs typically aim to mitigate wildfire through the use of strategic prescribed burning during the cooler early dry season. However, it remains unclear as to the extent such environmental management concerns are being addressed by these renewed fire management efforts. This study documents changes in fire regime in the western Arnhem Land region of northern Australia associated with the implementation of active fire management since 2006. Over a 12-year period, the regional fire regime has transitioned from late dry season, wildfire-dominated to being characterised by a majority of fires occurring as small early dry season prescribed burns. Although overall area burnt has not significantly decreased, most ecological threshold metrics have improved, with the exception of those describing the maintenance of longer-unburnt habitat. Challenges involved with defining, delivering, monitoring and evaluating heterogeneity targets are discussed.

scholarly journals The influence of prescribed fire on the extent of wildfire in savanna landscapes of western Arnhem Land, Australia

2012 ◽  
Vol 21 (3) ◽  
pp. 297 ◽  
Author(s):  
Owen F. Price ◽  
Jeremy Russell-Smith ◽  
Felicity Watt
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Prescribed Fire ◽  
Fire History ◽  
Prescribed Burning ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Dry Season ◽  
Gas Emissions ◽  
Arnhem Land

Fire regimes in many north Australian savanna regions are today characterised by frequent wildfires occurring in the latter part of the 7-month dry season. A fire management program instigated from 2005 over 24 000 km2 of biodiversity-rich Western Arnhem Land aims to reduce the area and severity of late dry-season fires, and associated greenhouse gas emissions, through targeted early dry-season prescribed burning. This study used fire history mapping derived mostly from Landsat imagery over the period 1990–2009 and statistical modelling to quantify the mitigation of late dry-season wildfire through prescribed burning. From 2005, there has been a reduction in mean annual total proportion burnt (from 38 to 30%), and particularly of late dry-season fires (from 29 to 12.5%). The slope of the relationship between the proportion of early-season prescribed fire and subsequent late dry-season wildfire was ~–1. This means that imposing prescribed early dry-season burning can substantially reduce late dry-season fire area, by direct one-to-one replacement. There is some evidence that the spatially strategic program has achieved even better mitigation than this. The observed reduction in late dry-season fire without concomitant increase in overall area burnt has important ecological and greenhouse gas emissions implications. This efficient mitigation of wildfire contrasts markedly with observations reported from temperate fire-prone forested systems.

Contemporary fire regime risks to key ecological assets and processes in north Australian savannas

2015 ◽  
Vol 24 (6) ◽  
pp. 857 ◽  
Author(s):  
Andrew Edwards ◽  
Jeremy Russell-Smith ◽  
Mick Meyer
Keyword(s):  
Climate Change ◽  
Prescribed Burning ◽  
Fire Management ◽  
Fire Regime ◽  
Ghg Emissions ◽  
Fire Regimes ◽  
Dry Season ◽  
Suspended Sediment Transport ◽  
Change Models ◽  
Positive Effects

Despite the intact appearance of relatively unmodified north Australian savannas, mounting evidence indicates that contemporary fire regimes characterised by frequent, extensive and severe late dry season wildfires are having deleterious effects on a range of regional water, soil erosion, biodiversity conservation and greenhouse gas (GHG) emissions values. For the high rainfall (>1000 mm year–1) savannas (426 000 km2), we assessed the spatial effects of contemporary fire regimes within the context of ecosystem response models and three plausible alternative fire management scenarios on ecosystem attributes. Over the 2008–12 assessment period, mean annual fire frequency (0.53) comprised mostly late dry season fires. Although spatially variable, contemporary fire regimes resulted in substantial GHG emissions, hill slope erosion and suspended sediment transport, a slight decline in carbon biomass and slight positive effects on fire-vulnerable vegetation. Based on available climate change models and strategic fire management practice, we show that, relative to business-as-usual, improved fire management involving strategic prescribed burning results in substantial benefits to most ecosystem attributes, including under enhanced climate change conditions, whereas in the absence of improved fire management, climate change results in substantially worse outcomes.

The distribution and conservation status of Carpentarian grasswrens (Amytornis dorotheae), with reference to prevailing fire patterns

2015 ◽  
Vol 21 (4) ◽  
pp. 291 ◽  
Author(s):  
Graham N. Harrington ◽  
Stephen A. Murphy
Keyword(s):  
Prescribed Burning ◽  
Fire Management ◽  
Conservation Status ◽  
Population Decline ◽  
Northern Territory ◽  
Tropical Savannas ◽  
Area Of Occupancy ◽  
Fire Patterns ◽  
Population Restoration

The Carpentarian grasswren (Amytornis dorotheae) is a small, shy passerine patchily distributed through Triodia systems in the central and southern parts of Australia’s tropical savannas. Population decline has been reported in the Northern Territory, presumably due to mismanaged fire. The species is considered Endangered in the Northern Territory and Near Threatened in Queensland, but it is not listed Federally. Here, we present the results of over 3000 surveys conducted between 2008 and 2013. We show that Carpentarian grasswrens are divided into four populations, although the northernmost one (Borroloola) now appears to be extinct. The Area of Occupancy for the southernmost population appears to have declined by 28%, while only small numbers of isolated birds now occur at the two intervening populations. Our data suggest that the four populations appear to be at different stages on an extinction pathway, from population decline, to fragmentation and isolation, to extinction, and this seems to be related to worsening fire patterns as one moves northwards. We suggest that the Carpentarian grasswren be listed as Vulnerable at the State and Federal level, and that urgent investment in long-term regional fire management using prescribed burning is required to reverse the declines in the extant populations. For the presumed extinct Borroloola population, restoration will probably need to involve translocation coupled with effective fire management.

Challenges for prescribed fire management in Australia’s fire-prone rangelands – the example of the Northern Territory

2020 ◽  
Vol 29 (5) ◽  
pp. 339 ◽  
Author(s):  
Jeremy Russell-Smith ◽  
Andrew C. Edwards ◽  
Kamaljit K. Sangha ◽  
Cameron P. Yates ◽  
Mark R. Gardener
Keyword(s):  
Prescribed Fire ◽  
Prescribed Burning ◽  
Fire Management ◽  
Greenhouse Gas Emission ◽  
Fire Spread ◽  
Northern Territory ◽  
Remote Communities ◽  
Management Planning ◽  
The Status ◽  
Planning Processes

Northern Australia comprises by far the most fire-prone-half of a fiery continent, where fire frequencies range from annual in the tropical savannas to periodic very-extensive fire events following above-rainfall conditions in the central Australian rangelands. As illustration of the challenges facing effective fire management in Australia’s 5.7×106km2 rangelands, we examine the status of contemporary prescribed burning activities in the Northern Territory, a 1.4×106km2, very sparsely settled (0.18 persons km−2) jurisdiction characterised by vast flammable landscapes, few barriers to fire-spread, predominantly anthropogenic ignitions, and limited institutional resources and capacity. Unsurprisingly, prescribed-fire management is shown to be restricted to specific locales. For more effective, landscape-scale fire management, potential solutions include engagement with dispersed remote communities and incorporation of Indigenous Ranger Groups into the fire-management network, and building on the success of savanna-burning greenhouse gas emission projects as an example for incentivising landscape fire and emergency management services generally. Recently, significant steps have been taken towards implementing formal regional fire-management planning processes involving inclusive community-stakeholder engagement, and the setting of clearly defined time-constrained objectives and targets.

scholarly journals A reconstruction of the recent fire regimes of Majete Wildlife Reserve, Malawi, using remote sensing

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie
Keyword(s):  
Remote Sensing ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Dry Season ◽  
Annual Rainfall ◽  
Vegetation Types ◽  
Local Evidence ◽  
Hot Dry Season ◽  
Wildlife Reserve

Abstract Background Fire is an important process that shapes the structure and functioning of African savanna ecosystems, and managers of savanna protected areas use fire to achieve ecosystem goals. Developing appropriate fire management policies should be based on an understanding of the determinants, features, and effects of prevailing fire regimes, but this information is rarely available. In this study, we report on the use of remote sensing to develop a spatially explicit dataset on past fire regimes in Majete Wildlife Reserve, Malawi, between 2001 and 2019. Moderate Resolution Imaging Spectroradiometer (MODIS) images were used to evaluate the recent fire regime for two distinct vegetation types in Majete Wildlife Reserve, namely savanna and miombo. Additionally, a comparison was made between MODIS and Visible Infrared Imager Radiometer Suite (VIIRS) images by separately evaluating selected aspects of the fire regime between 2012 and 2019. Results Mean fire return intervals were four and six years for miombo and savanna vegetation, respectively, but the distribution of fire return intervals was skewed, with a large proportion of the area burning annually or biennially, and a smaller proportion experiencing much longer fire return intervals. Variation in inter-annual rainfall also resulted in longer fire return intervals during cycles of below-average rainfall. Fires were concentrated in the hot-dry season despite a management intent to restrict burning to the cool-dry season. Mean fire intensities were generally low, but many individual fires had intensities of 14 to 18 times higher than the mean, especially in the hot-dry season. The VIIRS sensors detected many fires that were overlooked by the MODIS sensors, as images were collected at a finer scale. Conclusions Remote sensing has provided a useful basis for reconstructing the recent fire regime of Majete Wildlife Reserve, and has highlighted a current mismatch between intended fire management goals and actual trends. Managers should re-evaluate fire policies based on our findings, setting clearly defined targets for the different vegetation types and introducing flexibility to accommodate natural variation in rainfall cycles. Local evidence of the links between fires and ecological outcomes will require further research to improve fire planning.

scholarly journals A late-Holocene multiproxy fire record from a tropical savanna, eastern Arnhem Land, Northern Territory, Australia

The Holocene ◽  
2021 ◽  
pp. 095968362098803
Author(s):  
Emma Rehn ◽  
Cassandra Rowe ◽  
Sean Ulm ◽  
Craig Woodward ◽  
Michael Bird
Keyword(s):  
Isotope Composition ◽  
Fire Regimes ◽  
Northern Territory ◽  
Ecosystem Dynamics ◽  
Optical Methods ◽  
Fire Intensity ◽  
Tropical Savanna ◽  
Anthropogenic Fire ◽  
Pyrogenic Carbon ◽  
Arnhem Land

Fire has a long history in Australia and is a key driver of vegetation dynamics in the tropical savanna ecosystems that cover one quarter of the country. Fire reconstructions are required to understand ecosystem dynamics over the long term but these data are lacking for the extensive savannas of northern Australia. This paper presents a multiproxy palaeofire record for Marura sinkhole in eastern Arnhem Land, Northern Territory, Australia. The record is constructed by combining optical methods (counts and morphology of macroscopic and microscopic charcoal particles) and chemical methods (quantification of abundance and stable isotope composition of pyrogenic carbon by hydrogen pyrolysis). This novel combination of measurements enables the generation of a record of relative fire intensity to investigate the interplay between natural and anthropogenic influences. The Marura palaeofire record comprises three main phases: 4600–2800 cal BP, 2800–900 cal BP and 900 cal BP to present. Highest fire incidence occurs at ~4600–4000 cal BP, coinciding with regional records of high effective precipitation, and all fire proxies decline from that time to the present. 2800–900 cal BP is characterised by variable fire intensities and aligns with archaeological evidence of occupation at nearby Blue Mud Bay. All fire proxies decline significantly after 900 cal BP. The combination of charcoal and pyrogenic carbon measures is a promising proxy for relative fire intensity in sedimentary records and a useful tool for investigating potential anthropogenic fire regimes.

Bayes Nets as a method for analysing the influence of management actions in fire planning

2011 ◽  
Vol 20 (8) ◽  
pp. 909 ◽  
Author(s):  
T. D. Penman ◽  
O. Price ◽  
R. A. Bradstock
Keyword(s):  
Process Model ◽  
Management Practices ◽  
Prescribed Burning ◽  
Fire Management ◽  
Relative Reduction ◽  
Holistic Model ◽  
Bayes Nets ◽  
Management Actions ◽  
Fire Planning ◽  
In Fire

Wildfire can result in significant economic costs with inquiries following such events often recommending an increase in management effort to reduce the risk of future losses. Currently, there are no objective frameworks in which to assess the relative merits of management actions or the synergistic way in which the various combinations may act. We examine the value of Bayes Nets as a method for assessing the risk reduction from fire management practices using a case study from a forested landscape. Specifically, we consider the relative reduction in wildfire risk from investing in prescribed burning, initial or rapid attack and suppression. The Bayes Net was developed using existing datasets, a process model and expert opinion. We compared the results of the models with the recorded fire data for an 11-year period from 1997 to 2000 with the model successfully duplicating these data. Initial attack and suppression effort had the greatest effect on the distribution of the fire sizes for a season. Bayes Nets provide a holistic model for considering the effect of multiple fire management methods on the risk of wildfires. The methods could be further advanced by including the costs of management and conducting a formal decision analysis.

Thinking honeyeater: nectar maps for the Northern Territory, Australia

2000 ◽  
Vol 6 (1) ◽  
pp. 61 ◽  
Author(s):  
John C. Z. Woinarski ◽  
Greg Connors ◽  
Don C. Franklin
Keyword(s):  
Northern Territory ◽  
Dry Season ◽  
Spatial And Temporal Variation ◽  
Wet Season ◽  
Nectar Production ◽  
The World ◽  
Eucalypt Forests ◽  
The Times ◽  
Species Specific ◽  
Nectar Availability

We create monthly maps of nectar availability for the 1.4 x 106 km2 jurisdiction of the Northern Territory, Australia. These are based on a combination of vegetation mapping and a series of indices of plant species specific nectar scoring. The maps reveal complex spatial and temporal variation in nectar availability, but most notably a greater nectar resource in the monsoon-influenced north than in the arid south, and a peak in nectar availability in the dry season. The latter is associated with the extensive tropical eucalypt forests (especially those co-dominated by Eucalyptus miniata and E. tetrodonta). In contrast, wet season nectar availability in these forests is limited, but riparian and swampland forests, typically dominated by Melaleuca species, provide rich but spatially restricted nectar resources. The extensive and rich nectar resources available in eucalypt forests in the dry season supplement the diets of many species which are not primarily nectarivorous. This resource helps shape the singularity of northern Australian eucalypt forests relative to other extensive forests elsewhere in the world. Nectarivores remain in the system through a combination of movements across a number of scales, habitat shifting, and diet shifting. The latter is aided by the peaking of invertebrate and fruit resources at the times of minimum nectar production; a shuffling in resource availability brought about by the extreme climatic seasonality.

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