Frequency and season of fires varies with distance from settlement and grass composition in Eucalyptus miniata savannas of the Darwin region of northern Australia

2009 ◽  
Vol 18 (1) ◽  
pp. 61 ◽  
Author(s):  
Louis P. Elliott ◽  
Donald C. Franklin ◽  
David M. J. S. Bowman
Keyword(s):  
Fire History ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Dry Season ◽  
Perennial Grasses ◽  
Northern Australia ◽  
Landsat Images ◽  
Fire Cycle ◽  
Annual Grasses ◽  
Key Issues

In savanna environments, fire and grass are inextricably linked by feedback loops. In the Darwin area of northern Australia, flammable tall annual grasses of the genus Sarga (previously Sorghum1) have been implicated in a savanna fire-cycle. We examined the relationship between fire history, the grass layer and distance from settlement using LANDSAT images and plot-based surveys. Areas more than 500 m from settlement were burnt almost twice as often, the additional fires being concentrated late in the dry season and in areas dominated by annual Sarga and even more so where dominated by short annual grasses. Grass cover was a stronger correlate of fire frequency than grass biomass, the two showing a non-linear relationship. Sites dominated by short annual grasses had similar cover to, but markedly lower biomass than those dominated by annual Sarga or perennial grasses. Our results reflect the success of fire suppression in the vicinity of settlements, but little effective management of late dry-season wildfires in remoter areas. We evaluate several hypotheses for the association of frequent fire with annual grasses regardless of their growth form and conclude that fuel connectivity and possibly other fuel characteristics are key issues worthy of further investigation.

Fire regimes and their correlates in the Darwin region of northern Australia

2007 ◽  
Vol 13 (3) ◽  
pp. 177 ◽  
Author(s):  
Owen Price ◽  
Bryan Baker
Keyword(s):  
Fire History ◽  
Ad Hoc ◽  
Fire Regime ◽  
Negative Impact ◽  
Fire Suppression ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Dry Season ◽  
Generalized Linear Modelling

A nine year fire history for the Darwin region was created from Landsat imagery, and examined to describe the fire regime across the region. 43% of the region burned each year, and approximately one quarter of the fires occur in the late dry season, which is lower than most other studied areas. Freehold land, which covers 35% of the greater Darwin region, has 20% long-unburnt land. In contrast, most publicly owned and Aboriginal owned land has very high fire frequency (60-70% per year), and only 5% long unburnt. It seems that much of the Freehold land is managed for fire suppression, while the common land is burnt either to protect the Freehold or by pyromaniacs. Generalized Linear Modelling among a random sample of points revealed that fire frequency is higher among large blocks of savannah vegetation, and at greater distances from mangrove vegetation and roads. This suggests that various kinds of fire break can be used to manage fire in the region. The overall fire frequency in the Darwin region is probably too high and is having a negative impact on wildlife. However, the relatively low proportion of late dry season fires means the regime is probably not as bad as in some other regions. The management of fire is ad-hoc and strongly influenced by tenure. There needs to be a clear statement of regional fire targets and a strategy to achieve these. Continuation of the fire mapping is an essential component of achieving the targets.

Changes in forest fire frequency in Kootenay National Park, Canadian Rockies

1990 ◽  
Vol 68 (8) ◽  
pp. 1763-1767 ◽  
Author(s):  
Alan M. Masters
Keyword(s):  
Forest Fire ◽  
Rocky Mountains ◽  
National Park ◽  
Fire History ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Ice Age ◽  
Distribution Analysis ◽  
Fire Cycle ◽  
Time Since Fire

Time-since-fire distribution analysis is used to estimate forest fire frequency for the 1400 km2 Kootenay National Park, British Columbia, located on the west slope of the Rocky Mountains. The time-since-fire distribution indicates three periods of different fire frequency: 1988 to 1928, 1928 to 1788, and before 1788. The fire cycle for the park was > 2700 years for 1988 to 1928, 130 years between 1928 and 1788, and 60 years between 1778 and 1508. Longer fire cycles after 1788 and 1928 may be due, respectively, to cool climate associated with the Little Ice Age and a recent period of higher precipitation. Contrary to some fire history investigations in the region, neither a fire suppression policy since park establishment in 1919, nor the completion of the Windermere Highway through the park in 1923 appear to have changed the fire frequency from levels during pre-European occupation. Spatial partitioning of the time-since-fire distribution was unsuccessful. No relationship was found between elevation or aspect and fire frequency. Key words: fire cycle, Rocky Mountains, climate change.

Fire frequency for the transitional mixedwood forest of Timiskaming, Quebec, Canada

2005 ◽  
Vol 35 (3) ◽  
pp. 656-666 ◽  
Author(s):  
Daniel J Grenier ◽  
Yves Bergeron ◽  
Daniel Kneeshaw ◽  
Sylvie Gauthier
Keyword(s):  
Fire History ◽  
Fire Suppression ◽  
Sampling Strategy ◽  
Fire Frequency ◽  
Management Approach ◽  
Land Use Patterns ◽  
Temporal Shift ◽  
Fire Cycle ◽  
Old Growth Forest ◽  
Time Required

Fire history was reconstructed for a 2500-km2 area at the interface between the boreal coniferous and northern hardwood forests of southwestern Quebec. The fire cycle, the time required for an area equal to the study site to burn once over, was described using a random sampling strategy that included dendrochronological techniques in conjunction with provincial and national government archival data. Physiographic elements were not found to spatially influence fire frequency; however, human land-use patterns were observed to significantly affect the fire frequency. A temporal shift in fire frequency was also detected, which coincided with the period of Euro-Canadian colonization and known extreme dry years for the study site. Additionally, a fire-free period was identified in the most recent times that could be associated with fire suppression and climate change. The estimated cycles (approx. 188–314 years) for the southeastern section of the study area were thought to better represent the natural cycles for this transition zone as a result of less anthropogenic influence. The importance of gap-type dynamics becomes evident with the increased presence of old-growth forest, given the derived fire cycle estimations for the region. Even-aged management with short rotations, consequently, is questioned because fire cycle estimations suggest more complex harvest systems using an ecosystem management approach.

Fire severity in a northern Australian savanna landscape: the importance of time since previous fire

2010 ◽  
Vol 19 (1) ◽  
pp. 46 ◽  
Author(s):  
Brett P. Murphy ◽  
Jeremy Russell-Smith
Keyword(s):  
Fire History ◽  
Fire Severity ◽  
Severity Index ◽  
Fire Frequency ◽  
Dry Season ◽  
Strong Increase ◽  
Northern Australia ◽  
Feedback Process ◽  
Clear Trend ◽  
In Fire

Using a detailed fire history collected over a 10-year period throughout a savanna landscape in northern Australia, we have addressed the question of whether fire severity, inferred from a semiquantitative fire severity index, increases with time since previous fire. There was a clear trend of fires becoming much more severe with increasing time since previous fire. Between 1 and 5 years following a fire, the probability of a subsequent fire being classified as ‘severe’ increased from 3 to 8% for early dry-season fires, and from 21 to 43% for late dry-season fires. It was clear that the strong increase in fire severity was not confined to the first 2–3 years following the previous fire, as previously suspected. These findings highlight the difficulty of reducing both fire frequency and severity in northern Australian savanna landscapes, as they imply that a negative feedback process exists between the two; that is, reducing fire frequency is likely to increase the severity of fires that do occur.

Declining fires in Larix-dominated forests in northern Irkutsk district

2011 ◽  
Vol 20 (2) ◽  
pp. 248 ◽  
Author(s):  
Tuomo Wallenius ◽  
Markku Larjavaara ◽  
Juha Heikkinen ◽  
Olga Shibistova
Keyword(s):  
20Th Century ◽  
Forest Fires ◽  
Fire History ◽  
18Th Century ◽  
Fire Suppression ◽  
Tree Ring Chronology ◽  
Fire Cycle ◽  
History Of ◽  
Historical Accounts ◽  
Additional Explanation

To study the poorly known fire history of Larix-dominated forest in central Siberia, we collected samples from 200 trees in 46 systematically located study plots. Our study area stretches ~90 km from north to south along the River Nizhnyaya Tunguska in northern Irkustk district. Cross-dated tree-ring chronology for all samples combined extended from the year 1360 AD to the present and included 76 fire years and 88 separate fire events. Average fire cycle gradually lengthened from 52 years in the 18th century to 164 years in the 20th century. During the same time, the number of recorded fires decreased even more steeply, i.e. by more than 85%. Fires were more numerous but smaller in the past. Contrary to expectations, climate change in the 20th century has not resulted in increased forest fires in this region. Fire suppression may have contributed to the scarcity of fires since the 1950s. However, a significant decline in fires was evident earlier; therefore an additional explanation is required, a reduction in human-caused ignitions being likely in the light of historical accounts.

scholarly journals Contextualizing the 2019–2020 Kangaroo Island Bushfires: Quantifying Landscape-Level Influences on Past Severity and Recovery with Landsat and Google Earth Engine

2020 ◽  
Vol 12 (23) ◽  
pp. 3942
Author(s):  
Mitchell T. Bonney ◽  
Yuhong He ◽  
Soe W. Myint
Keyword(s):  
Time Series ◽  
Vegetation Change ◽  
Fire History ◽  
South Australia ◽  
Fire Frequency ◽  
Google Earth ◽  
Bivariate Analysis ◽  
Landsat Images ◽  
Google Earth Engine ◽  
Landscape Level

The 2019–2020 Kangaroo Island bushfires in South Australia burned almost half of the island. To understand how to avoid future severe ‘mega-fires’ and how vegetation may recover from 2019–2020, we can utilize information from the bulk of historical fires in an area. Landsat time-series of vegetation change provide this opportunity, but there has been little analysis of large numbers of fires to build a landscape-level understanding and quantify drivers in an Australian context. In this study, we built a yearly cloud-free surface reflectance normalized burn ratio (NBR) time-series (1988–2020) using all available summer Landsat images over Kangaroo Island. Data were collected in Google Earth Engine and fitted with LandTrendr. Burn severity and post-fire recovery were quantified for 47 fires, with a new recovery metric facilitating comparison where fire frequency is high. Variables representing the current burn, fire history, vegetation structure, and topography were related to severity and yearly recovery with random forest and bivariate analysis. Results show that the 2019–2020 bushfires were the most widespread and severe, followed by 2007–2008. Vegetation recovers quickly, with NBR stabilizing ten years post-fire on average. Severity is most influenced by fire frequency, vegetation capacity and land use with more severe burns in nature conservation areas with dense vegetation and a history of frequent fires. Influence on recovery varied with time since fire, with initial (year 1–3) faster recovery observed in areas with less surviving vegetation. Later (year 6–10) recovery was most influenced by a variable representing burn year and further investigation indicates that precipitation increases in later post-fire years likely facilitated faster recovery. The relative abundance of eucalypt woodlands also has a positive influence on recovery in middle and later years. These results provide valuable information to land managers on Kangaroo Island and in similar environments, who should consider adjusting practices to limit future mega-fire risk and potential ecosystem shifts if severe fires become more frequent with climate change.

Seasonal use of savanna landscapes by the Gouldian finch, Erythrura gouldiae, in the Yinberrie Hills area, Northern Territory

2001 ◽  
Vol 28 (4) ◽  
pp. 445 ◽  
Author(s):  
P. L. Dostine ◽  
G. C. Johnson ◽  
D. C. Franklin ◽  
Y. Zhang ◽  
C. Hempel
Keyword(s):  
Full Range ◽  
Northern Territory ◽  
Dry Season ◽  
Perennial Grasses ◽  
Grass Species ◽  
Wet Season ◽  
Themeda Triandra ◽  
Annual Grasses ◽  
Gouldian Finch ◽  
Hills Area

The diet, attributes of feeding sites and patterns of seasonal movements of a population of the Gouldian finch, Erythrura gouldiae, were studied in the Yinberrie Hills area north of Katherine in the Northern Territory. In the dry season (April–November) Gouldian finches foraged mostly on burnt ground and fed on exposed seed of annual grasses, especially seed of spear-grass, Sorghum spp. In the wet season (December–March) Gouldian finches fed on seed of a sequence of perennial grass species, including Themeda triandra, Alloteropsis semialata, Chrysopogon fallax and Heteropogon triticeus. Gouldian finches undertake regular seasonal shifts in habitat, from breeding areas in hill woodland in the dry season to adjacent lowlands throughout much of the wet season, in response to seasonal changes in food availability. There is an annual pulse in abundance of fallen seed in the early dry season that is depleted to near zero levels by germination of annual grasses early in the wet season. Thereafter, finches depend on seed from other sources, principally ripe and ripening seed of perennial grasses. Observations over three successive wet seasons suggest that Gouldian finches track seed resources provided by seeding perennial grasses over an extensive area of lowland grassy woodland adjacent to the breeding area, favouring small patches of grassy woodland for brief periods until seed fall. There were subtle differences between years in the types of resources used. Management of Gouldian finch populations will entail protection and management of the full range of grassland habitats used throughout the annual cycle, and will require predictive knowledge of the causes of patterning of seed resources and probably an ability to exert control over the timing and extent of fires in fire-prone seasonal savanna landscapes.

Fire history of the San Francisco East Bay region and implications for landscape patterns

2005 ◽  
Vol 14 (3) ◽  
pp. 285 ◽  
Author(s):  
Jon E. Keeley
Keyword(s):  
Native Americans ◽  
20Th Century ◽  
San Francisco ◽  
Fire History ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Landscape Patterns ◽  
East Bay ◽  
Anthropogenic Fires

The San Francisco East Bay landscape is a rich mosaic of grasslands, shrublands and woodlands that is experiencing losses of grassland due to colonization by shrubs and succession towards woodland associations. The instability of these grasslands is apparently due to their disturbance-dependent nature coupled with 20th century changes in fire and grazing activity. This study uses fire history records to determine the potential for fire in this region and for evidence of changes in the second half of the 20th century that would account for shrubland expansion. This region has a largely anthropogenic fire regime with no lightning-ignited fires in most years. Fire suppression policy has not excluded fire from this region; however, it has been effective at maintaining roughly similar burning levels in the face of increasing anthropogenic fires, and effective at decreasing the size of fires. Fire frequency parallels increasing population growth until the latter part of the 20th century, when it reached a plateau. Fire does not appear to have been a major factor in the shrub colonization of grasslands, and cessation of grazing is a more likely immediate cause. Because grasslands are not under strong edaphic control, rather their distribution appears to be disturbance-dependent, and natural lightning ignitions are rare in the region, I hypothesize that, before the entrance of people into the region, grasslands were of limited extent. Native Americans played a major role in creation of grasslands through repeated burning and these disturbance-dependent grasslands were maintained by early European settlers through overstocking of these range lands with cattle and sheep. Twentieth century reduction in grazing, coupled with a lack of natural fires and effective suppression of anthropogenic fires, have acted in concert to favor shrubland expansion.

Fire and carbon management in a diversified rangelands economy: research, policy and implementation challenges for northern Australia

2014 ◽  
Vol 36 (4) ◽  
pp. 313 ◽  
Author(s):  
Dionne Walsh ◽  
Jeremy Russell-Smith ◽  
Robyn Cowley
Keyword(s):  
Land Management ◽  
Management Practices ◽  
Research Policy ◽  
Management Practice ◽  
Fire Suppression ◽  
Ghg Emissions ◽  
Complete Removal ◽  
Dry Season ◽  
Management Tool ◽  
Northern Australia

Burning of savanna is a globally important source of greenhouse gas (GHG) emissions. In Australia, burning of savanna contributes between 2% and 4% annually of the nation’s reportable emissions. Complete removal of this source of emissions is unrealistic because fire is a ubiquitous natural process and important land-management tool. In the rangelands of northern Australia, fire is used to manage habitat for conservation, control woodland thickening, manipulate pastures for grazing and is an essential component of indigenous cultural and land-management practice. There has been a concerted attempt in recent times to move away from complete fire suppression and its consequence: frequent, extensive and high intensity wildfires occurring late in the dry season. In fire-adapted vegetation types, prescribed early dry season fires help reduce the incidence of late season wildfires and consequently the amount of GHG emissions produced. The emergence of a carbon economy affords a potential opportunity for land managers to diversify their livelihoods by adopting fire-management practices that reduce GHG emissions and increase carbon sequestration. However, in order to realise benefits from this emerging economy, there is a need to identify and address a range of barriers affecting community participation. The papers in this Special Issue document current scientific knowledge, policy issues and pathways to participation, with particular reference to Australia’s savanna rangelands. This introductory paper outlines how northern Australia has both the opportunity and requirement to develop a diversified rangelands economy to realise multiple conservation, economic and emissions outcomes.

How hot? How often? Getting the fire frequency and timing right for optimal management of woody cover and pasture composition in northern Australian grazed tropical savannas. Kidman Springs Fire Experiment 1993–2013

2014 ◽  
Vol 36 (4) ◽  
pp. 323 ◽  
Author(s):  
Robyn A. Cowley ◽  
Mark H. Hearnden ◽  
Karen E. Joyce ◽  
Miguel Tovar-Valencia ◽  
Trisha M. Cowley ◽  
...  
Keyword(s):  
Fire Regime ◽  
Vegetation Type ◽  
Fire Frequency ◽  
Perennial Grasses ◽  
Tropical Savannas ◽  
Heteropogon Contortus ◽  
Pasture Degradation ◽  
Annual Grasses ◽  
Woody Cover ◽  
The Impact

A long-term (1993–2013) experiment in grazed semiarid tropical savannas in northern Australia tested the impact of varying the frequency (every 2, 4 and 6 years) and season (June – EDS versus October – LDS) of fire compared with unburnt controls on woody cover and pasture composition, in grassland and open woodland. Over an 18-year period, woody cover increased by 4% (absolute) in the woodland even with the most severe (i.e. frequent, late dry season) fire treatments. With less severe or no fire, woody cover increased by 12–17%. In the grassland, woody cover remained static when subjected to LDS fires every 2 or 4 years, but increased by 3–6% under other fire treatments, and by 8% when unburnt. Major shifts in understorey species composition occurred at both sites regardless of fire regime. The effect of fire on herbage mass and composition was compounded by higher grazing after fires. The herbage mass of perennial grasses declined and that of annual grasses and forbs increased following early or frequent fires. Brachyachne convergens, Gomphrena canescens and Flemingia pauciflora increased in response to fire while Aristida latifolia and Heteropogon contortus decreased. Four-yearly LDS fire provided the most effective management of woody cover and pasture composition. Although EDS fire is recommended for biodiversity management and reducing greenhouse gas emissions in wet tropical savannas, on grazed pastoral land, it can promote woodland thickening and pasture degradation. Optimal fire management, therefore, depends on vegetation type, land use and the prevailing seasonal timing and frequency of fire.

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