An analysis of fire frequency in tropical savannas of northern Australia, using a satellite-based fire atlas

Oliveira, Sofia L. J.; Turkman, Maria Antónia Amaral; Pereira, José M. C.

doi:10.1071/wf12021

Cited by 12 publications

(15 citation statements)

References 34 publications

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“…Western Arnhem Land is under aboriginal tenure, and traditional owners have been using fire as a land management tool for thousands of years, for ‘cleaning up’ the country and facilitate walking, hunting, and to encourage growth of plant and animal foods. In general, there were also similarities between fire frequency in the different physiognomies of JSP and those from northern Australia, reported by [36]. In both studies the fire incidence was higher in woodland and herbaceous-shrubbery physiognomies (SS and OW for JSP and woodlands and open forests in WAL).…”

Section: Discussionsupporting

confidence: 72%

Modelling Fire Frequency in a Cerrado Savanna Protected Area

et al. 2014

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Covering almost a quarter of Brazil, the Cerrado is the world’s most biologically rich tropical savanna. Fire is an integral part of the Cerrado but current land use and agricultural practices have been changing fire regimes, with undesirable consequences for the preservation of biodiversity. In this study, fire frequency and fire return intervals were modelled over a 12-year time series (1997–2008) for the Jalapão State Park, a protected area in the north of the Cerrado, based on burned area maps derived from Landsat imagery. Burned areas were classified using object based image analysis. Fire data were modelled with the discrete lognormal model and the estimated parameters were used to calculate fire interval, fire survival and hazard of burning distributions, for seven major land cover types. Over the study period, an area equivalent to four times the size of Jalapão State Park burned and the mean annual area burned was 34%. Median fire intervals were generally short, ranging from three to six years. Shrub savannas had the shortest fire intervals, and dense woodlands the longest. Because fires in the Cerrado are strongly responsive to fuel age in the first three to four years following a fire, early dry season patch mosaic burning may be used to reduce the extent of area burned and the severity of fire effects.

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Section: Discussionsupporting

confidence: 72%

Modelling Fire Frequency in a Cerrado Savanna Protected Area

et al. 2014

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“…The 83% and 93% values reflect levels of the burned area in EDS and LDS fires found in this study, and the bounding 50% and 100% values are used for comparisons. A random number drawn from a lognormal distribution (as described in Oliveira et al 2013) was used to determine whether a location burnt in any one year. A burnt location could be re-populated (probability R) if there were no fires for seven subsequent years (to reflect the life cycle of above obligate seeder taxa), determined by a random number proportional to the overall population size (R=N/500 if N<500 and R=1 if N>=500).…”

Section: Discussionmentioning

confidence: 99%

Ecological Implications of Fine-Scale Fire Patchiness and Severity in Tropical Savannas of Northern Australia

et al. 2015

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Understanding fine-scale fire patchiness has significant implications for ecological processes and biodiversity conservation. It can affect local extinction of and recolonisation by relatively immobile fauna and poorly seeddispersed flora in fire-affected areas. This study assesses fine-scale fire patchiness and severity, and associated implications for biodiversity, in north Australian tropical savanna systems. We used line transects to sample burning patterns of ground layer vegetation in different seasons and vegetation structure types, within the perimeter of 35 fires that occurred between 2009 and 2011. We evaluated two main fire characteristics: patchiness (patch density and mean patch length) and severity (inferred from char and scorch heights, and char and ash proportions). The mean burned area of ground vegetation was 83% in the early dry season (EDS: May to July) and 93% in the late dry season (LDS: August to November). LDS fires were less patchy (smaller and fewer unburned patches), and had higher fire severity (higher mean char and scorch heights, and twice the proportion of ash) than EDS fires. Fire patchiness varied among vegetation types, declining under more open canopy structure. The relationship between burned area and fire severity depended on season, being strongly correlated in the EDS and uncorrelated in the LDS. Simulations performed to understand the implications of patchiness on the population dynamics of fire-interval sensitive plant species showed that small amounts of patchiness substantially enhance survival. Our results indicate that the ecological impacts of high frequency fires on fire-sensitive regional biodiversity elements are likely to be lower than has been predicted from remotely sensed studies that are based on assumptions of homogeneous burning. interval-sensitive plant species showed that small amounts of patchiness substantially enhance survival. Our results indicate that the ecological impacts of high frequency fires on fire-sensitive regional biodiversity elements are likely to be lower than has been predicted based on assumptions of homogeneous burning derived from remotely sensed studies.

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“…For example, an average of 36% of the area of western Arnhem Land was burnt each year from 1990 to 2008 (Oliveira et al. ) and 46% of the area of Kakadu National Park was burnt each year from 1980 to 1994 (Russell‐Smith et al. ).…”

Section: Introductionmentioning

confidence: 99%

“…Although human population density remains very low, a high portion of land is burnt per year. For example, an average of 36% of the area of western Arnhem Land was burnt each year from 1990 to 2008 (Oliveira et al 2013) and 46% of the area of Kakadu National Park was burnt each year from 1980 to 1994 (Russell-Smith et al 1997). The percentage of land burnt in Kakadu was as high as 70% in 2014 and 2015 (cf.…”

Section: Introductionmentioning

confidence: 99%

Savanna canopy trees under fire: long‐term persistence and transient dynamics from a stage‐based matrix population model

Werner

Peacock

2019

Ecosphere

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Fire is a major disturbance driving the dynamics of the world's savannas. Almost all fires are set by humans who are increasingly altering fire timing and frequency on every continent. The world's largest protected areas of savannas are found in monsoonal northern Australia. These include relatively intact, tall, open forests where traditional indigenous fire regimes have been largely replaced in the past half century by contemporary patterns with trees experiencing fire as often as three out of five years. Eucalypt canopy trees form the basic structure of these savannas and changes to the canopy due to fire regimes cascade to affect other plants and animals. In this study, we used data from nearly three decades of field studies on the effects of fire on individual trees to define eight life‐history stages and to calculate transition rates among stages. We developed a stage‐based matrix population model that explicitly considers how fire season and understory influence growth, survival, and recruitment for each life‐history stage. Long‐term population growth rates and transient population dynamics were calculated under five different fire regimes, each in two understory types, using both deterministic and stochastic simulations of seasonal timing of fires. We found that fire was necessary for long‐term persistence of eucalypt canopy tree populations but, under annual fires, most populations did not survive. Population persistence was highly dependent on fire regime (fire season and frequency) and understory type. A stochastic model tended to yield higher population growth rates than the deterministic model with regular, periodic fires, even under the same long‐term frequency of fires. Transient population dynamics over 100 yr also depended on fire regime and understory, with implications for savanna physiognomy and management. Model predictions were tested in an independent data set from a 21‐yr longitudinal field study in Kakadu National Park. This study is a novel and integrative contribution to our understanding of fire in savanna biomes regarding the potential for long‐term persistence and transient dynamics of savanna canopy tree populations. The model is relatively simple, generalizable, and adaptable for further investigations of the population dynamics of savanna trees under fire.

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An analysis of fire frequency in tropical savannas of northern Australia, using a satellite-based fire atlas

Cited by 12 publications

References 34 publications

Modelling Fire Frequency in a Cerrado Savanna Protected Area

Modelling Fire Frequency in a Cerrado Savanna Protected Area

Ecological Implications of Fine-Scale Fire Patchiness and Severity in Tropical Savannas of Northern Australia

Savanna canopy trees under fire: long‐term persistence and transient dynamics from a stage‐based matrix population model

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