Article

The fire history of south-west Western Australia prior to European settlement in 1826-1829

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  • Sydney and Xi'an
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... Fire Recurrent fires of uncertain frequency have been part of the Western Australian landscape for at least several million years (Hassell and Dodson 2003) and certainly since human arrival (Bowman 2003). Some studies suggest possible frequencies of 3 -4 fires per decade in the Perth area before 1860 (Abbott 2003;Lamont et al. 2003). ...
... The species in Kings Park, like those throughout the south west of Western Australia, have evolved in a fire prone environment. Fire was present in the Western Australian landscape well before humans arrived (Hassell and Dodson 2003) and once Aborigines arrived in Australia, fire regimes undoubtedly changed due to human utilization of fire for hunting and landscape management. Unfortunately it is not possible to completely understand the pre-Eurpoean fire regimes but fires were certainly recorded as frequent occurrences in the landscape in the early 1800s (Abbott 2003). ...
... However, the idea that lack of fire leads to understorey thickening is at odds with Beard's (1967) conclusions that it is frequent fires that have driven the decline of tuart (and jarrah) while the understorey has become denser. Close Before European arrival the west coast of the south of western Australia was relatively densely populated in Aboriginal terms, and anthropogenic fires on the coastal plain may have been at about 2 -3 year intervals (Hassell and Dodson 2003). It is likely that this sort of fire regime produced the woodland structure of tuart vegetation reported by the early European settlers and is evidenced by the sparse (mostly moribund or dead) large tuarts in Kings Park. ...
Thesis
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Introduction Banksia woodland is the characteristic mediterranean type vegetation of the sand plains of the Swan Coastal Plain in the Perth region of Western Australia. Once extensive in the past the woodlands are nowadays severely fragmented and threatened by a variety of perturbations including weeds, fire and seed predation. Conservation and management of the woodlands depends very much upon the knowledge of past land use, type of original vegetation, frequency and magnitude of significant disturbances and surrounding land-use. The results of a long-term study in the Kings Park bushland, comparing vegetation differences between the 1939 and 1999, showed that there have been substantial changes in the composition and structure of the woodland. In term of tree species, the most significant trends have been a decrease in Banksia spp. Aim The research reported in this thesis aims for an understanding of the features and different stages of Banksia spp. recruitment in an environment such as the Kings Park bushland urban remnant. The final objective of this study is to assess if recruitment of Banksia spp. is affected by the perturbations mentioned above, ultimately influencing bushland conservation. Materials &Methods The study was conducted both in urban bushland and in suburban areas in the Perth region. Several of the experiments and investigations on some specific stages of recruitment also included other species dominant in the bushland. The stages of recruitment investigated are: seed production and dispersal, seed germination and seedling establishment, seed predation. Results In the Perth region B. attenuata and B. menziesii have a small degree of serotiny, the two species release seeds at different times of the year - B. attenuata from Summer to Autumn and B. menziesii from Spring to Summer. In post- fire conditions seed release is more synchronised than for unburned trees but the amount of seed released depends on the timing of the fire. Fires in early Summer lead to mass release of B. menziesii seeds and destruction of immature seeds of B. attenuata. Later fires destroy B. menziesii seed that has been shed on to the soil but synchronises release of B. attenuata seed. Of the investigated locations Kings Park, and Ridge State Forest, have higher level of pre-dispersal seed predation compared to other locations. The post-dispersal surveys and experiment, both in inter-fire and post-fire environment show that in Kings Park in Winter, approximately 75% of the banksia seeds were consumed. Moreover, Banksia seed predation is not related to the density of seeds. Presence of leaf litter, weeds and plant material in the experimental unit reduced predation values. Most of the germination occurred on sandy soil, while presence of weeds and of a thick layer of leaf litter reduced germination numbers for the Banksia species. In post-fire conditions seedlings are also associated with “burn residuals” (accumulation of burned litter and ash). Most of the seeds that were sown in the soil and had germinated died. Conclusion This project confirmed and quantified the decrease of banksia individuals (which until now was only assumed) over time and lack of their recruitment. Seed predation, both before and after seed release greatly affects banksia seed availability in Kings Park. Furthermore unfavourable sites for germination such as a thick layer of leaf litter and weeds are a great obstacle for establishment of large seeded species such as Banksia. Other dominant species, such as Allocasuarina fraseriana, Acacia saligna and Dryandra sessilis1 on the contrary do not seem to reduce their recruitment potential as predation (or removal) is not conspicuous and the various substrata do not reduce the ratio between the number of germinants and seedlings that survive. In order to boost banksia recruitment a number of management actions could be taken. In particular weeds and thick layers of leaf litter must be removed and a sandy soil substratum should be arranged especially in the areas where, even in the presence of banksia trees, the number of seedlings is low. Predation must be reduced, in particular through removal of pests. http://researchrepository.murdoch.edu.au/id/eprint/10692/
... Heath vegetation in southwest WA has evolved through recurring fires and typically possesses traits suited to post-fire regeneration (Keeley, 1995). Historically, the presence or absence of Aborigines has had a strong influence on fire regimes in WA (Hassell and Dodson, 2003). Fire intervals of 30 to 100+ years have been inferred from lake sediment charcoal deposits in areas with no Aboriginal inhabitants (Hassell and Dodson, 2003). ...
... Historically, the presence or absence of Aborigines has had a strong influence on fire regimes in WA (Hassell and Dodson, 2003). Fire intervals of 30 to 100+ years have been inferred from lake sediment charcoal deposits in areas with no Aboriginal inhabitants (Hassell and Dodson, 2003). Where Aboriginal burning occurred, however, fires were typically more frequent, depending on population density and the practices of individual groups (Hassell and Dodson, 2003). ...
... Fire intervals of 30 to 100+ years have been inferred from lake sediment charcoal deposits in areas with no Aboriginal inhabitants (Hassell and Dodson, 2003). Where Aboriginal burning occurred, however, fires were typically more frequent, depending on population density and the practices of individual groups (Hassell and Dodson, 2003). Fire intervals have been altered further under European management (Lambrook, 2015). ...
Article
This study aims to determine the common response of coastal sand dunes in Western Australia (WA) to fire on decadal time-scales, in terms of ecological-geomorphic-climatic interactions to test the hypothesis that fire plays a role in coastal dune destabilisation. Fires are commonly suggested to have contributed to widespread dune reactivation in Australia and globally, a hypothesis that is relatively untested. We used data from the Landsat Thematic Mapper, Enhanced Thematic Mapper Plus, and Operational Land Imager missions to monitor changes in surface coverage on coastal sand dunes in south-west WA after fires. We analysed 31 fire scars from 1988 to 2016 in two Landsat scenes on the west and south coast of WA. Recovery ratios derived from the Normalised Difference Vegetation Index (NDVI) were used to monitor patterns in post-fire biomass and surface cover. Recovery ratios are correlated with indices of burn severity, and meteorological data to investigate relationships. We also used Maximum Likelihood Classification to monitor changes in bare sand area. Results suggest that recovery followed a strongly consistent pattern, and is characterised by rapid vegetation cover re-establishment within six to twelve months. Prior to this, some aeolian activity may have occurred but without substantial surface changes. Initial germination and/or resprouting were followed by steady growth up to seven years, where NDVI typically neared pre-fire values. Some variation in early recovery occurred between the west and south coast, possibly owing to relative proportions of reseeding and resprouting plants. A log regression explained 75% of the recovery pattern (79% on the south coast). Precipitation had some ability to explain recovery up to nine months post-fire (r² = 0.29 to 0.54). No relationships were observed between estimates of burn severity and recovery. After nine months, the biggest cause of spatial variation in recovery was the pre-fire community composition and related seedbank or resprouting density. Image classification did not identify any new blowout features except where fires were not the primary cause. Results suggest that fires are not presently contributing to the destabilisation of coastal dunes in south-west WA.
... Combined with poor dispersal capacities and a complex mosaic of soil types, this gives rise to numerous edaphically-specialized populations, and high rates of speciation ensue [11] (see also [12]). This kind of speciation would have become more frequent in the later Tertiary as the climate became drier and the flora became dominated by flammable scleromorphic species, increasing fire frequency [13]. ...
... Hopper [2,10] suggested that more complex erosional patterns in the TRZ led to recurrent fragmentation and isolation of populations in the late Tertiary and Quaternary, hence more rapid speciation, while the comparative stability of the lateritic soils in the HRZ favoured larger, more persistent populations, and a lower extinction rate. Under Cowling's hypothesis, the rate of speciation is linked to the frequency and intensity of fire, both of which vary substantially across different ecosystem types in the SWBP [13]. Hence, this hypothesis also predicts variation in diversification rates within the SWBP. ...
... If fires were more frequent and intense in the densely-vegetated sclerophyll forests, compared to the more sparsely-vegetated heaths and shrublands, extinction resulting from population fragmentation may have been more frequent in the HRZ. There is some evidence that the forests have been more fire-prone than the heaths and shrublands over the comparatively recent period of human occupation of southwestern Australia [30], but there are little data with which to infer geographic variation in fire patterns across the region over the deeper timescales relevant to macroevolution [13]. ...
Article
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Hotspots of angiosperm species richness and endemism in Mediterranean-climate regions are among the most striking, but least well-understood, geographic patterns of biodiversity. Recent studies have emphasized the importance of rapid diversification within hotspots, compared to non-hotspot regions, as a major contributor to these patterns. We constructed the first near-complete phylogeny of Banksia (Proteaceae) to test whether diversification rates have differed between lineages confined to the southwest Australian hotspot and those found throughout southern, eastern and northern Australia. We then tested for variation in diversification rates among the bioclimatic zones within the southwest hotspot itself. Although Banksia species richness in the southwest is ten times that of the rest of the continent, we find little evidence for more rapid diversification in the southwest, although this result is inconclusive. However, we find firmer support for substantial rate variation within the southwest hotspot, with more rapid diversification in the semi-arid heaths and shrublands, compared to the high-rainfall forests. Most of the Banksia diversity of the southwest appears to be generated in the heaths and shrublands, with a high migration rate out of this zone boosting diversity of the adjacent forest zone. The geographic pattern of diversification in Banksia appears more complex than can be characterized by a simple hotspot vs. non-hotspot comparison, but in general, these findings contrast with the view that the high diversity of Mediterranean hotspots is underpinned by rapid radiations. Steady accumulation of species at unexceptional rates, but over long periods of time, may also have contributed substantially to the great botanical richness of these regions.
... The climate is Mediterranean with hot dry summers (Dec -Feb) and cool wet winters (May -Aug) where average annual rainfall ranges from 800 to 1100 mm along a east-to-west gradient (BOM, 2022). Fire history in the Jarrah Forest prior to European settlement was largely shaped by frequent low intensity Aboriginal burning particularly within inhabited areas, and infrequent high intensity wildfire occurring every 30-100þ years (Hassell and Dodson, 2003). Since the 1960s, much of the Jarrah Forest has been treated with low intensity prescribed burns at 6-to 12-year intervals (Burrows and McCaw, 2013;Hassell and Dodson, 2003). ...
... Fire history in the Jarrah Forest prior to European settlement was largely shaped by frequent low intensity Aboriginal burning particularly within inhabited areas, and infrequent high intensity wildfire occurring every 30-100þ years (Hassell and Dodson, 2003). Since the 1960s, much of the Jarrah Forest has been treated with low intensity prescribed burns at 6-to 12-year intervals (Burrows and McCaw, 2013;Hassell and Dodson, 2003). ...
Article
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Plant phenology describes the timing of reproductive events including flowering and fruiting, which for many species are affected by fire disturbance. Understanding phenological responses to fire provides insights into how forest demographics and resources may shift alongside increasing fire frequency and intensity driven by climate change. However, isolating the direct effects of fire on a species' phenology and excluding potential confounders (e.g. climate, soil) has been difficult due to the logistical challenges of monitoring species-specific phenological events across myriad fire and environmental conditions. Here, we use CubeSat-derived crown-scale flowering data to estimate the effects of fire history (time since fire and fire severity over a 15-year time span) on flowering of the eucalypt Corymbia calophylla across a Mediterranean-climate forest (814km2) in southwest Australia. We found that fire reduced the proportion of flowering trees at the landscape-scale, and flowering recovered at a rate of 0.15 % (±0.11% SE) per year. Further, this negative effect was significant due to high crown scorch fires (>20% canopy scorch), yet there was no significant effect from understory burns. Estimates were obtained using a quasi-experimental design which identifies the effect of time since fire and severity on flowering by comparing proportional flowering within target fire perimeters (treatment) and adjacent past fire perimeters (control). Given the majority of fires studied were managed fuel reduction burns, we applied the estimates to hypothetical fire regimes to compare flowering outcomes under more or less frequent prescribed burning. This research demonstrates the landscape-scale effects of burning on a tree species' reproduction, which could broadly impact forest resiliency and biodiversity.
... The history of fire in southwest Western Australia has been reasonably well documented and provides evidence of land management through cultural burning by Australian Indigenous peoples dating back centuries (Hassell & Dodson, 2002). While offshore islands, such as the Recherche, were only occasionally burned by Aboriginal communities (major fires set at intervals of up to 100 years), mainland areas were burned every 1-10 years (Hassell & Dodson, 2002). ...
... The history of fire in southwest Western Australia has been reasonably well documented and provides evidence of land management through cultural burning by Australian Indigenous peoples dating back centuries (Hassell & Dodson, 2002). While offshore islands, such as the Recherche, were only occasionally burned by Aboriginal communities (major fires set at intervals of up to 100 years), mainland areas were burned every 1-10 years (Hassell & Dodson, 2002). The fire event on Figure of Eight Island serves as a catalyst to develop a monitoring and research project that is focused on seabird colonies, associated habitat mapping, and structural vegetation survey based on the cultural knowledge and scientific understanding that faunal biodiversity is likely to be maximised by avoiding widespread, intense bushfires (Bamford & Roberts, 2003). ...
Article
Traditional burning regimes have long been employed to enhance biodiversity and mitigate high-intensity wildfires. The link between changes in the distribution, success, and timing of breeding in seabirds and climatic and oceanographic variation in the marine environment has been established, with migratory seabirds less able to respond to climate variability than resident species. While climate-driven changes can also occur on seabird breeding islands, few data are available regarding potential impacts. Here we investigate the frequency and severity of bushfires on seabird breeding islands in Western Australia, regarding the 2020 fire on Figure of Eight Island in the Recherche Archipelago. A lack of quantitative, historical surveys limited our ability to quantify the number of shearwaters lost in this event. However, a review of available data suggests thousands of birds die due to burning every one or two years across the Archipelago. On Figure of Eight, shearwater burrow occupancy and density were low 12 months post-burn (0.25 and 0.02 ± 0.03, respectively), with minimal evidence of recovery (very few burrows detected) 23 months post-burn. We discuss opportunities to develop an adaptive, community-based program for reinstating collaborative, cultural methods of fire management and monitoring regimes on seabird breeding islands in Australia.
... We have evidence of the frequency of natural fires in Australia and Western Australia during the previous 2-3 million years (Mooney and al. 2011). This is based on carbon fragments and pollen grains of fire-following species of the Gyrostemonaceae found in cores drilled into the base of ancient lakes, and at the Yallalie impact crater east of Jurien Bay (Hassell and Dodson 2003;Dodson et al. 2005). Fire frequencies in the fire-prone sandplain habitat at Yallalie averaged 12-14 years 3 million years ago, compared with 81 years in the jarrah forest before European settlement (Burrows et al. 1995), and from 80 to 100 years 3000-4000 years ago on the south-eastern coast of Western Australia, now the Fitzgerald River National Park (Hassell and Dodson 2003). ...
... This is based on carbon fragments and pollen grains of fire-following species of the Gyrostemonaceae found in cores drilled into the base of ancient lakes, and at the Yallalie impact crater east of Jurien Bay (Hassell and Dodson 2003;Dodson et al. 2005). Fire frequencies in the fire-prone sandplain habitat at Yallalie averaged 12-14 years 3 million years ago, compared with 81 years in the jarrah forest before European settlement (Burrows et al. 1995), and from 80 to 100 years 3000-4000 years ago on the south-eastern coast of Western Australia, now the Fitzgerald River National Park (Hassell and Dodson 2003). The best evidence of pre-Aboriginal fire regimes indicates that they were extremely variable, potentially of limited landscape-scale impact and depended on location, with fire frequencies ranging from 12-14 years in semiarid parts of Western Australia to 80-100 years in the jarrah forest on the Darling Scarp and along the south coast (Enright and Thomas 2008). ...
Article
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Wildfires are expected to increase worldwide both in frequency and intensity owing to global warming, but are likely to vary geographically. This is of particular concern in the five mediterranean regions of the world that are all biodiversity hotspots with extraordinary plant and animal diversity that may be impacted by deliberately imposed fire. Wildland managers attempt to reduce the impact and mitigate the outcomes of wildfires on human assets and biodiversity by the use of prescribed burning. The response that we must ‘fight fire with fire’ is understandable, perceived as reducing the flammability of wildlands in fire-prone regions and lessening the impact of wildfires. The long-term impact on biodiversity is, however, less clear. The practice of prescribed burning has been in place and monitored in south-western Australia for 50 years, longer and more intensively than in most other mediterranean ecosystems. The present target is for 200 000 ha burned each year in this biodiversity hotspot. Published studies on the impact of this burning on infrastructure protection and on biodiversity are here used to understand the protective capacity of the practice and to foreshadow its possible long-term ecological impact across all mediterranean ecosystems.
... We only have indirect evidence of the frequency of natural fires and their impact on plants in WA going back 2-3 million years, based on carbon fragments and pollen grains found in cores drilled into the base of ancient lakes and at Yallalie, a meteorite crater east of Jurien Bay [14]. Fires, started by lightning strikes, are common, long before the arrival of Aborigines in SW Australia some 40-50,000 years ago, based on deposits found in Devil's Lair Cave [15]. ...
... Fires, started by lightning strikes, are common, long before the arrival of Aborigines in SW Australia some 40-50,000 years ago, based on deposits found in Devil's Lair Cave [15]. Fire frequencies in the fire-prone sandplain habitat at Yallalie averaged 6-14 years 3 million years ago [16], compared with 81 years in the jarrah forest prior to European settlement [17] and from 80 to 100 years 3-4,000 years ago on the southeast coast that is now the Fitzgerald River National Park [14]. ...
Technical Report
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Any rational discussion of fire policy and its impact on biodiversity must take into consideration the very special circumstances that exist in the southwest of Western Australia. There are 34 acknowledged “biodiversity hotspots” currently under threat in the world. Only one of these is in Australia and this is in the southwest corner of WA[1, 2] (see Fig 1) Threatened biodiversity hotspots are defined as: “areas where “exceptional concentrations of endemic species are undergoing exceptional loss of habitat”
... Historical fire intervals range from ~10 years in the north to 140 years in the south. Data for contemporary fire intervals indicate major changes in the southern (shortened fire intervals) but little change in the northern parts of the species' geographic range ( Fig. 8; data for fire intervals from 18,19,[70][71][72][73] ). ...
... The paired-end sequences corresponding to the selected SE were extracted for further assembly. The selected pair-end reads were input into the Velvet sequence assembler, and k-mer 40 was used for B. attenuata contig assembly 72 . Assembled contigs less than 200 bp were excluded from further analysis. ...
Article
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Substantial climate changes are evident across Australia, with declining rainfall and rising temperature in conjunction with frequent fires. Considerable species loss and range contractions have been predicted; however, our understanding of how genetic variation may promote adaptation in response to climate change remains uncertain. Here we characterized candidate genes associated with rainfall gradients, temperatures, and fire intervals through environmental association analysis. We found that overall population adaptive genetic variation was significantly affected by shortened fire intervals, whereas declining rainfall and rising temperature did not have a detectable influence. Candidate SNPs associated with rainfall and high temperature were diverse, whereas SNPs associated with specific fire intervals were mainly fixed in one allele. Gene annotation further revealed four genes with functions in stress tolerance, the regulation of stomatal opening and closure, energy use, and morphogenesis with adaptation to climate and fire intervals. B. attenuata may tolerate further changes in rainfall and temperature through evolutionary adaptations based on their adaptive genetic variation. However, the capacity to survive future climate change may be compromised by changes in the fire regime.
... Historical fire intervals range from ~10 years in the north to 140 years in the south. Data for contemporary fire intervals indicate major changes in the southern (shortened fire intervals) but little change in the northern parts of the species' geographic range ( Fig. 8; data for fire intervals from 18,19,[70][71][72][73] ). ...
... The paired-end sequences corresponding to the selected SE were extracted for further assembly. The selected pair-end reads were input into the Velvet sequence assembler, and k-mer 40 was used for B. attenuata contig assembly 72 . Assembled contigs less than 200 bp were excluded from further analysis. ...
Article
Full-text available
Substantial climate changes are evident across Australia, with declining rainfall and rising temperature in conjunction with frequent fires. Considerable species loss and range contractions have been predicted; however, our understanding of how genetic variation may promote adaptation in response to climate change remains uncertain. Here we characterized candidate genes associated with rainfall gradients, temperatures, and fire intervals through environmental association analysis. We found that overall population adaptive genetic variation was significantly affected by shortened fire intervals, whereas declining rainfall and rising temperature did not have a detectable influence. Candidate SNPs associated with rainfall and high temperature were diverse, whereas SNPs associated with specific fire intervals were mainly fixed in one allele. Gene annotation further revealed four genes with functions in stress tolerance, the regulation of stomatal opening and closure, energy use, and morphogenesis with adaptation to climate and fire intervals. B. attenuata may tolerate further changes in rainfall and temperature through evolutionary adaptations based on their adaptive genetic variation. However, the capacity to survive future climate change may be compromised by changes in the fire regime.
... Red Tingle (Eucalyptus jacksonii) trees dominate tall, wet forests in a geographically restricted, high rainfall area of south-western Australia (Wardell-Johnson & Coates, 1997). All indicators are that fire was highly infrequent in these forests prior to British invasion (Wardell-Johnson, 2000;Wardell-Johnson et al., 2018), with only very rare traces of charcoal in lake sediments (Hassell & Dodson, 2003), and almost no fire scars in the E. diversicolor trees that can co-occur with Red Tingle (Rayner, 1992). Long exclusion of fire from these forests does not lead to replacement of these dominant overstorey trees by other species (Wardell-Johnson, 2000). ...
Article
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Empirical evidence in scientific literature shows that forest flammability in south‐western Australia declines as forests recover from disturbance, indicating that current policies mandating disturbance may be counterproductive. Zylstra et al. (2023) used mechanistic modelling to explain this trend in Red Tingle (Eucalyptus jacksonii) forest in south‐western Australia. McCaw. (2024) have questioned the validity of the modelling, advancing hypothetical arguments as to why one of the inputs (‘suspended litter’) is incorrect and re‐asserting the need for the current policy. The primary argument by McCaw. (2024) depends upon the redefinition of a component of surface litter into suspended litter. The published definition of near‐surface fuel defines necromass as ‘suspended’ fuel only if it is suspended in living plants or collapsed shrubs. McCaw. (2024) removed this requirement, so that a component of surface fuel was incorrectly measured as ‘suspended’ fuel long after the plants that might suspend it had self‐thinned from the landscape. This physically impossible assertion was supported by an empirical study led by an architect of the policy and utilising the same redefinition of suspended litter, also reporting physically impossible findings as a result. Given the well‐documented decline in wildfire likelihood in long‐unburnt forest, the claim by McCaw. (2024) that suspended litter does not decline suggests at best that such litter plays a lesser role than previously believed. The approaches used by McCaw. (2024) to defend Government policy should be understood in context of growing international concerns around scientific suppression used in defence of Government policy. Read the free Plain Language Summary for this article on the Journal blog.
... Charcoal traces were rare in south-western Australian forests (Hassell & Dodson, 2003), and almost no fire scars prior to invasion were recorded in the tall-open forests dominated by E. diversicolor that merge with our study area (Rayner, 1992). The earlier mentioned argument that this lack of evidence for fire indicates fire of such frequency that the lack of fuels and subsequent low intensity of fire left no record in the landscape (Bowman, 2003;Burrows et al., 1995;Gammage, 2011;Mariani et al., 2022) is problematic for four reasons. ...
Article
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Forest wildfire impact is widely believed to increase with time since disturbance, presenting a dilemma for the persistence of fire‐sensitive species. However, in south‐western Australia, disturbance has been shown to increase wildfire likelihood for some decades before it again declines. It has been proposed that this trend occurs through ‘ecological controls’ on wildfire such as the self‐thinning of fire‐stimulated understorey growth. Here, we analyse six proposed ecological controls using a surveyed chronosequence of a Eucalyptus jacksonii forest community. We quantify plant growth (growth and self‐pruning) and succession (changing plant traits, self‐thinning), along with consequent changes in surface and suspended litter. We then use a biophysical, mechanistic model to predict the dynamics of flame height and canopy scorch/consumption, along with suppression difficulty during wildfire conditions. To identify the importance of each potential ecological control, we separately manipulate them to grow hypothetical forests from 1 to 100 years; each with one of the controls removed. We then model flame height in each to compare with the original forest that had all controls present. Fire initially promoted dense understorey regeneration, but ecological controls transferred this biomass from fuel (likely to ignite) to overstorey shelter (unlikely to ignite, creating a less flammable microclimate). The effect of these changes was to alter modelled fire behaviour, such that flame dimensions in mature forest were half those in regrowth, canopy damage greatly reduced, and fire suppression opportunities maximised. The primary controls were self‐thinning and self‐pruning. Forest growth and succession explains observed trends in flammability dynamics in south‐western Australian forests, and the persistence of fire‐sensitive species over time. Approaches that cooperate with, rather than disrupt, these processes therefore provide a pathway to mitigate current climatic effects on fire. Read the free Plain Language Summary for this article on the Journal blog.
... [1] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Plant fire response obligate seeders Obligate seeders are killed by fire that causes 100% canopy scorch or girdles the stem at or near ground level and germinate either from seed stored in the soil or on the plant in woody capsules (serotinous species). For obligate seeders the time required to re-establish seed banks after germination is critical, if a second lethal fire occurs before a population has produced sufficient seed it may decline or become locally extinct. ...
... In some ecosystems, such as subalpine forests, climate and weather determine the flammability of the system, while in others, such as seasonally dry forests, a consistent fire season means vegetation or fuel availability is the determining factor (Bessie & Johnson, 1995;Littell et al., 2009;Schoennagel et al., 2004). Even if weather and fuels (vegetation) are sufficient to support fire, a well-timed ignition is still required to initiate the fire and humans have augmented natural ignitions for centuries to millennia (Balch et al., 2017;Hassell & Dodson, 2002;Kershaw, 1986;Liebmann et al., 2016). The fire regimes that developed in seasonally dry forests influenced the structure and composition of the vegetation, which, in turn, influenced the way that fire interacted with the vegetation. ...
Article
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Climate, disturbance, vegetation response and their interaction are key factors in predicting the distribution and function of ecosystems across landscapes. A range of factors, operating through different pathways, are amplifying the feedbacks in this three‐way interaction. In the western USA, the relative strength of the influence of climate versus vegetation on fire activity varies spatially, realizing a diversity of fire regimes and fire‐selected species traits under historical conditions of climate–fire–vegetation interactions. Human intervention, via land use and fire‐exclusion, has homogenized frequent‐fire‐adapted forests in terms of structure and composition. Climate change is reinforcing the homogenization directly via increasing temperatures and drought and indirectly through climate‐driven tree mortality. The net effect will be forming novel climate–fire–vegetation interactions that act to homogenize fire regimes and catalyse large‐scale forest loss. While long‐term persistence of tree species in a given location may not be possible due to directional change of climate, slowing the rate of wildfire‐driven forest cover loss and maximizing the in‐situ persistence of a diversity of species will allow forest ecosystems to respond more incrementally to changing climate and provide an opportunity for ecosystem reassembly to occur from a large pool of species. As climate continues to change, management to resist wildfire‐driven forest cover loss may hinge on reducing forest density and creating a higher level of heterogeneity to reach the resistance and resilience exhibited by pre‐fire‐exclusion forests. Management operations should better leverage disturbance while strategically deploying silvicultural treatments to increase managed and prescribed fire. Further research is needed to improve our capacity for quantifying key mechanisms and system responses involved in the climate–fire–vegetation interactions and predicting how best to allocate resources to manage for functional forests. Read the free Plain Language Summary for this article on the Journal blog.
... The understorey contains smaller trees and shrubs ranging in height from 2 to 7 m, such as Banksia grandis (bull banksia), Allocasuarina fraseriana (sheoak), and Xanthorrhoea preissii (grass trees) (Dell et al., 1991). Fire has been a frequent and consistent occurrence in the NJF (Boer et al., 2009;Bradshaw et al., 2018;Dell et al., 1991;Hassell and Dodson, 2003). Currently, government agencies apply a system of wildfire mitigation with low-intensity frequent prescribed burning to maintain a fuel age of less than six years since last burnt in at least 45% of the southwest forest regions (DBCA, 2020). ...
Article
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Fire managers seek accurate methods to map fire severity for forest management efforts. Fire severity data with wide spatial and temporal coverage enhances understanding of fire's impact on vegetation and improves planning to mitigate the risk of destructive wildfires. In this study, we develop a machine learning workflow that converts a spatial database of known fire events into a collection of gridded fire severity maps representing levels of canopy scorch due to wildfires and planned fuel reduction burns (prescribed burns). This workflow uses a dataset of observed fire severity interpreted from post-fire aerial images (3–7 cm spatial resolution; ~11,649 labels from 64 unique fires) to train and test a supervised classifier that predicts fire severity using 13 Landsat-derived spectral indices. For a target fire, the classifier generates a pixel-level prediction of fire severity with classes belonging to one of five ordinal categories ranging from unburnt, three levels of canopy scorch, and canopy consumed by fire. The classifier's accuracy was 84.2% (Kappa score = 0.799) and testing was undertaken across multiple fire types (wildfire / prescribed burn), seasons, forest types and topography. MODIS thermal anomalies and a MODIS-derived burn area product were used to augment the fire severity database with start- and end-of-fire dates to enable accurate delineation of pre- and post-fire Landsat imagery; this method increased model accuracy from 78.0% (Kappa = 0.72). The model was then applied to a regional 16-year (2005 to 2020) history of fire events (n fires = 713, ~1Mha) in the sclerophyll eucalypt forests and woodlands of the Northern Jarrah Forest, Western Australia. On fires with MODIS-adjusted start and end dates, high severity fire (>80% canopy scorch) was predicted more often in wildfires (67.9%, 124900 ha) compared to prescribed burns (14.6%, 110300 ha). However, the total predicted area of high-severity fire was comparable between fire types due to prescribed burns being more frequent on the landscape. We provide the first fire severity model in Western Australia that is broadly calibrated to both prescribed burns and wildfires across multiple conditions. Our model outputs are made freely available and offer opportunities to better understand the interactions between prescribed burns and wildfires, and the effects of fire severity on the environment.
... Fire within BWs is a natural process with evidence of its occurrence dating back to 2.7 Â 10 6 -2.5 Â 10 6 years BP (Hassell and Dodson 2002). Fossil charcoal evidence of aboriginal use of fire within BWs dates back at least 30 000 years BP (Hallam 2014). ...
Article
The rapid expansion of urban areas worldwide is leading to native habitat loss and ecosystem fragmentation and degradation. Although the study of urbanisation's impact on biodiversity is gaining increasing interest globally, there is still a disconnect between research recommendations and urbanisation strategies. Expansion of the Perth metropolitan area on the Swan Coastal Plain in south-western Australia, one of the world's thirty-six biodiversity hotspots, continues to affect the Banksia Woodlands (BWs) ecosystem, a federally listed Threatened Ecological Community (TEC). Here, we utilise the framework of a 1989 review of the state of knowledge of BWs ecology and conservation to examine scientific advances made in understanding the composition, processes and functions of BWs and BWs' species over the last 30 years. We highlight key advances in our understanding of the ecological function and role of mechanisms in BWs that are critical to the management of this ecosystem. The most encouraging change since 1989 is the integration of research between historically disparate ecological disciplines. We outline remaining ecological knowledge gaps and identify key research priorities to improve conservation efforts for this TEC. We promote a holistic consideration of BWs with our review providing a comprehensive document that researchers, planners and managers may reference. To effectively conserve ecosystems threatened by urban expansion, a range of stakeholders must be involved in the development and implementation of best practices to conserve and maintain both biodiversity and human wellbeing.
... Fire within BWs is a natural process with evidence of its occurrence dating back to 2.7 Â 10 6 -2.5 Â 10 6 years BP (Hassell and Dodson 2002). Fossil charcoal evidence of aboriginal use of fire within BWs dates back at least 30 000 years BP (Hallam 2014). ...
Article
Full-text available
The rapid expansion of urban areas worldwide is leading to native habitat loss and ecosystem fragmentation and degradation. Although the study of urbanisation’s impact on biodiversity is gaining increasing interest globally, there is still a disconnect between research recommendations and urbanisation strategies. Expansion of the Perth metropolitan area on the Swan Coastal Plain in south-western Australia, one of the world’s thirty-six biodiversity hotspots, continues to affect the Banksia Woodlands (BWs) ecosystem, a federally listed Threatened Ecological Community (TEC). Here, we utilise the framework of a 1989 review of the state of knowledge of BWs ecology and conservation to examine scientific advances made in understanding the composition, processes and functions of BWs and BWs’ species over the last 30 years. We highlight key advances in our understanding of the ecological function and role of mechanisms in BWs that are critical to the management of this ecosystem. The most encouraging change since 1989 is the integration of research between historically disparate ecological disciplines. We outline remaining ecological knowledge gaps and identify key research priorities to improve conservation efforts for this TEC. We promote a holistic consideration of BWs with our review providing a comprehensive document that researchers, planners and managers may reference. To effectively conserve ecosystems threatened by urban expansion, a range of stakeholders must be involved in the development and implementation of best practices to conserve and maintain both biodiversity and human wellbeing.
... Fuel load reduction in forest ecosystems, particularly in Mediterranean climates, is of increasing importance because of a higher incidence of fire weather due to climate change (Enright et al. 2015). Contemporary prescribed burning aims to manage fuel loads and fuel structure to mitigate effects of wildfire and has been used in Australia since the 1950s (Burrows and McCaw 2013), although anthropogenic fire has been used in Australia for thousands of years, typically creating patchy mosaics of different aged vegetation (Hassell and Dodson 2003). The cessation of traditional Aboriginal burning practices and altered fire management (Bowman 1998, Abbott and, coupled with the loss of many digging mammals, means fuel loads are likely to be higher and more homogenous in contemporary times. ...
Article
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Digging animals may alter many characteristics of their environment as they disrupt and modify the ground's surface by creating foraging pits or burrows. Extensive disturbance to the soil and litter layer changes litter distribution and availability, potentially altering fuel loads. In many landscapes, including peri‐urban areas, fire management to reduce fuel loads is complex and challenging. The reintroduction of previously common digging animals, many of which are now threatened, may have the added benefit of reducing fuel loads. We experimentally examined how the reintroduction of a marsupial bandicoot, quenda (Isoodon fusciventer), altered surface fuel loads in an urban bush reserve in Perth, Western Australia. Foraging activities of quenda (where they dig for subterranean food) were substantial throughout the reserve, creating a visibly patchy distribution in surface litter. Further, in open plots where quenda had access, compared to fenced plots where quenda were excluded, quenda foraging significantly reduced litter cover and litter depth. Similarly, estimated surface fuel loads were nearly halved in open plots where quenda foraged compared to fenced plots where quenda were absent (3.6 cf. 6.4 Mg/ha). Fire behavior modeling, using the estimated surface fuel loads, indicated the predicted rate of spread of fire were significantly lower for open plots where quenda foraged compared to fenced plots under both low (29.2 cf. 51.4 m/h; total fuels) and high (74.3 cf. 130.4 m/h; total fuels) fire conditions. Although many environments require fire, including the bushland where this study occurred, fire management can be a considerable challenge in many landscapes, including urban bushland reserves, which are usually small and close to human infrastructure. The reintroduction of previously common digging species may have potential value as a complimentary tool for reducing fuel loads, and potentially, fire risk.
... Fire is a natural environmental factor that has shaped the floristic composition and structure of southwest Australian jarrah (Eucalyptus marginata Sm.) forests over many millennia (Dodson and Lu 2000;Hassell and Dodson 2003). Consequently, the plants display a great diversity of fire adaptations that enables them to persist with fire and, in many cases, the plants are dependent upon fire for their regeneration (Christensen and Kimber 1975;Christensen and Abbott 1989;Burrows and Wardell-Johnson 2003). ...
Article
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Prescribed burning is an important management tool in jarrah (Eucalyptus marginata Sm.) forests of southwest Western Australia to reduce the risk of damaging bushfires. In 1986 to 1987, we established long-term study sites in dry (mean annual rainfall ~700 mm) and moist (mean annual rainfall ~1000 mm) jarrah forests to assess the effects of prescribed burning, as well as other fire treatments including fire exclusion, on the composition, richness, and relative abundance of forest understory vegetation. Over almost 30 years, species assemblages within all fire treatments changed significantly through time, but the changes were independent of treatment. The pattern of change in composition of fire response types over elapsed time was different between sites. At the dry site, changes in species assemblages were initially relatively large in the first decade or so of the study, but slowed thereafter. At the moist site, compositional change driven by obligate seeding shrubs occurred faster and more uniformly with time across all treatments. Species richness was also independent of fire treatment at both sites. Species richness decreased with elapsed time on the moist site but increased with elapsed time on the dry site. The stronger elapsed-time effect rendered the time since fire effect on loss of species richness on the moist site to be insignificant, but there was an inverse relationship with time since fire at the dry site. Within each site, there were clear patterns of changing abundance based on life form and fire response groups, but this was not consistent between sites. At the scale of the current study, jarrah forest plant communities displayed resilience to imposed experimental fire regimes. Over time, either elapsed time or time since fire, species assemblages across all treatments changed regardless of fire treatment, but changes were mostly associated with specific plant life forms and fire response traits, suggesting that the process is both deterministic and stochastic. While many species changed in abundance over time, no species were lost as a result of the fire treatments. Within the fire frequency and intensity ranges investigated in this study, there was flexibility in the application of prescribed fire to achieve management objectives without loss of plant diversity.
... Intense crown fires may be less frequent in mesic banksia woodlands and open eucalypt forests, whereas ground surface fires at lower intensity in the same habitat are much more frequent (Hassell and Dodson 2003). Although the advantages of epicormic resprouting are apparent in ground-fire systems, seedlings and saplings are vulnerable to even mild fires because their protective structures (e.g. ...
Article
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Trait divergence between populations is considered an adaptive response to different environments, but to what extent this response is accompanied by genetic differentiation is less clear since it may be phenotypic plasticity. In this study, we analyzed phenotypic variation between two Banksia attenuata growth forms, lignotuberous (shrub) and epicormic resprouting (tree), in fire‐prone environments to identify the environmental factors that have driven this phenotypic divergence. We linked genotype with phenotype and traced candidate genes using differential gene expression analysis. Fire intervals determined the phenotypic divergence between growth forms in B. attenuata. A genome‐wide association study identified 69 single nucleotide polymorphisms, putatively associated with growth form, whereas no growth form‐ or phenotype‐specific genotypes were identified. Genomic differentiation between the two growth forms was low (Fst = 0.024). Differential gene expression analysis identified 37 genes/transcripts that were differentially expressed in the two growth forms. A small heat‐shock protein gene, associated with lignotuber presence, was differentially expressed in the two forms. We conclude that different fire regimes induce phenotypic polymorphism in B. attenuata, whereas phenotypic trait divergence involves the differential expression of a small fraction of genes that interact strongly with the disturbance regime. Thus, phenotypic plasticity among resprouters is the general strategy for surviving varying fire regimes.
... Landscape fire became increasingly prevalent in Australia at the time of Aboriginal settlement (Bowman 2003). Records suggest the Nyungar people, the original inhabitants of the SW, applied fire to the landscape from as far back as 60,000 years ago (Hassell and Dodson 2003;Hallam 2014). The introduction of human-induced fire had an extraordinary impact on the Australian landscape (Pyne 1991). ...
Article
The scale and intensity of bushfire activity in Australia is likely to increase as a result of climate change. Effective bushfire management policy measures are therefore essential to minimise the interrelated social, environmental and economic impacts of fire in the landscape. This paper presents a historical review of bushfire management in the South West of Australia (SW): a bushfire prone and biodiverse region. Using a worldview framework to analyse key policy documents and literature, the paper demonstrates that the evolution of complex policy sectors such as bushfire management, is influenced not only by scientific and technical developments but also as a result of changing worldviews. Adapting the Integrative Worldview Framework (IWF), seven worldview categories that dominated particular periods of history in Australia are presented. These worldview categories are then used to examine the evolution of bushfire management practice, policy and institutional arrangements relevant to the SW. The argument presented herein is that a better understanding of worldviews and how they influence complex and contentious policy fields such as bushfire management, is useful for policy analysis, reflexive practice and research. The paper suggests an integrative worldview approach, which enables opportunities for exchanges and constructive conflict between stakeholders and agencies with diverse worldviews, could contribute to creating more sustainable bushfire management. Finally, it is argued that opportunities for Indigenous and Western worldview exchanges in the bushfire management sector, through collaborative knowledge partnerships could assist the sector in both management practice and policy formulation.
... Other studies of fuel accumulation (Birk and Bridges 1989), fire risk (Boer et al. 2009) nutrient cycling, and tree health (Turner et al. 2008) in dry eucalypt systems have shown that burning at three to six year intervals can maintain dynamic stability and ecological resilience in these systems (Jurskis 2011b). Physical records (e.g., Singh et al. 1981, Burrows et al. 1995, Ward et al. 2001, Hassell and Dodson 2003, Mooney et al. 2011: Figure 2) and his-torical records (Mitchell 1848, Curr 1883, Howitt 1891, Abbott 2003, Gammage 2011) support these studies of ecological processes pointing to ecosystems shaped by extensive, frequent Aboriginal burning. ...
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There is a concept in fire ecology that some natural (pre-European) fire regimes were dominated by infrequent high intensity fires ignited by lightning. In Australia, some ecologists extend this to most or all ecosystems across the landscape. They regard contemporary human burning or prescribed burning as an unnatural disturbance that threatens biodiversity. Their particular concern is the potential extinction of slow maturing obligate seeders by frequent fire. However, a completely different picture emerges from study of Australia's ecological history and prehistory. There is ample evidence that Australian vegetation was shaped by thousands of years of frequent mild burning by Aborigines. Infrequent, high intensity lightning fires affected only small areas of wet forests in refuges that were physically protected from mild fires. We present a case study of ecosystems on the Sydney sandstones to demonstrate that a regime of infrequent high intensity wildfires since European settlement has caused structural changes and reduced spatial diversity. This has put many fire dependent plants at a competitive disadvantage and increased their susceptibility to disease.We argue that biodiversity, ecosystem health, and fire safety are threatened by lack of frequent mild fire. Ecological theory should build on ecological history. Australia is fortunate in having comprehensive historical records of Aboriginal burning against which paleoecological data can be calibrated. We emphasize the importance of using historical information to interpret ecological studies and inform fire management.
... Conditions in SW Australia are normally conducive to fires over a 4-8 month period, with lightning strikes a major source of ignition during summer and early autumn, resulting in intense and wide-spread fires (McCaw and Hanstrum 2003). The arrival of aborigines in the late Pleistocene instituted an anthropogenic fire regime, with a shortened fire interval in heavily occupied areas of 10-15 years (Hassell and Dodson 2003) or less. Fires were typically ignited from October to June, with most recorded for the hottest months from December to March (Abbott 2003). ...
Article
Species with fire stimulated reproduction (fsr) are common in Mediterranean climate ecosystems. We investigated how season of, and time since, fire affects seed production in Podocarpus drouynianus F. Muell., a dioecious resprouting coniferous shrub endemic to the jarrah (Eucalyptus marginata Sm.) forests of southwestern Australia, and if the now largely managed fire regime in these forests poses a risk to its persistence. We hypothesised that, like other species showing fsr, seed production in P. drouynianus would be limited to the first few years following fire and seed set would be lower after spring burns. Mature plants regenerated rapidly from buried stem tissue (lignotuber) after fire, producing abundant sporophylls in autumn 12–18 months later. Stands burnt in autumn showed peak seed production 1 year later, while for those burned in spring, peak seed production was delayed until the second autumn after fire. Limited seed production occurred for up to 3 years following fire, but no seed production was observed in longer unburnt (>10 years since fire) stands. While we did not observe a significant impact of fire season on seed production, seed weight and viability were lower for spring-burnt plants. Population-level effects associated with plant density may also have negative impacts on P. drouynianus demography, with females within a small population burnt in autumn producing very few seeds 12 months following fire. Interactions between climate change, fire regimes and fire management practices need to be considered in order to best safeguard the long-term persistence of this conifer species.
... Aboriginal people arrived in the south-west perhaps 40-50 thousand years ago and their management regimes undoubtedly had considerable impact on the forests and other environments of the region (Abbott 2003;Hassell and Dodson 2003). However, European settlement in Perth in 1829 (1826 in Albany: Fig. 1) elevated anthropogenic impact to a new level in numerous ways, including through the introduction of exotic animals, plants and microbes, deforestation and logging, and further changes in fire regimes (see Calver and Wardell-Johnson 2016 for an overview). ...
Article
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The environment of the northern jarrah (Eucalyptus marginata) forest (NJF) of Mediterranean-climate, south-western Australia is characterised by deeply weathered soil profiles and low fertility, reflecting long geological stasis. This fire-prone environment is characterised by primary forests of low productivity but high biomass. Since European settlement (1829), the NJF has been structurally transformed by deforestation and resource extraction, including logging and mining (principally for bauxite). Rainfall has declined by 15–20% since 1970, with projections for further decline. A new hydrological regime foreshadows regolith drying, with a changed climate leading to more unplanned, intense fires. Declining productivity, coupled with rehabilitation more suited to a wetter climate, places stress on tree growth and compromises biodiversity. Thus, ecological disruption likely follows from interactions between climate change and historical exploitation. The complex challenges posed by these interactions require multifaceted and novel solutions. We argue that under drying conditions, maintenance of productivity while conserving biodiversity can best be achieved by changing the focus of rehabilitation to the understorey. This would coincide with protecting and restoring surrounding unmined forest with emphasis on the overstorey. Presently, state-of-the-science rehabilitation seeks to restore jarrah forest, following bauxite mining. This goal is unlikely to be achievable across extensive areas under climate change projections. Rather, a focus on restoring understorey following mining would provide a more positive water balance in the wider forest matrix. This approach recognises loss of forest values through mining, but anticipates conservation of biodiversity and important elements of forest structure by minimising ecologically unacceptable disturbance to surrounding forest.
... Presently, tall wet forest dominated by Eucalyptus diversicolor (which occurs in the vicinity of the south-eastern cluster of populations) is less prone to fire than other eucalypt forest and woodland (the remainder of the K. coccinea range) (Murphy et al., 2013). In addition, there is evidence that southern tall wet forests were less utilized by Aboriginal people, and therefore less frequently burnt, than the northern jarrah forest and forest margins (Burrows et al., 1995;Hassell & Dodson, 2003). ...
Article
Aim Terrestrial plant ecology and evolution is significantly influenced by the phenomenon of fire, but studies of its potential impact on intraspecific genetic variation and phylogeography are rare. This understanding will be important for predicting the biogeographical consequences of changing fire regimes under global climate change. Here, we asked whether changing historical fire regimes, together with climatic and geological history, have influenced phylogeographical patterns in a fire‐ephemeral vine. We also asked whether demographic stochasticity associated with a fire‐ephemeral life history results in nuclear genetic drift as expected from spatio‐temporal patchiness, or if this effect is buffered by the connectivity and diversity afforded by a persistent soil seed bank. Location The fire‐prone, mediterranean‐type climate region of south‐western Australia. Methods We used Bayesian phylogeny reconstruction and statistical tests of demographic expansion based on variation at three non‐coding chloroplast sequence regions ( atpF, ndhF–rpl32, psbD–trnT ) to reconstruct phylogeographical history. Nuclear diversity and population structure at 11 microsatellite loci were investigated for evidence of genetic drift. Results Evidence for prolonged persistence and a lack of vicariance within the species range was found, together with strong evidence of historical demographic expansion. Contrary to expectations, there was little evidence of nuclear genetic drift despite strong, above‐ground spatio‐temporal population patchiness. Main conclusions Our findings suggest that a late Pleistocene increase in fire frequency may have led to demographic expansion in this fire‐ephemeral species; alternatively, the expansion signal may be an inherent feature of fire ephemerals with a persistent soil seed bank. Prolonged climatic stability has likely fostered persistence within the species range in contrast to contraction and vicariance. The notable lack of genetic drift implies a role for ample pollen dispersal and a long‐lived soil seed bank in the maintenance of diversity and connectivity in an otherwise stochastic, fire‐driven system.
... The assessment of the interval between burns is an important tool to detect human interference. Hassell and Dodson's (2003) charcoal-based study of the fire history of southwest Western Australia provides an example. They measured charcoal deposition over time during the Pleistocene and Holocene and found a decrease in the length of the fire intervals during the Holocene that cannot be ascribed to natural changes in fire-prone vegetation linked with climatic change. ...
... Such a bleak outlook is much less applicable to the kwongan of the Coolgardie Interzone. Here, beyond the clearing line, the landscape is largely intact and evolutionary processes are expected to continue, despite the depletion of the critical weight range mammal fauna (Burbidge & McKenzie, 1989) and presumed changes in the historic fire regimes (Hassell & Dodson, 2003;Parsons & Gosper, 2011). ...
... The assessment of the interval between burns is an important tool to detect human interference. Hassell and Dodson's (2003) charcoal-based study of the fire history of southwest Western Australia provides an example. They measured charcoal deposition over time during the Pleistocene and Holocene and found a decrease in the length of the fire intervals during the Holocene that cannot be ascribed to natural changes in fire-prone vegetation linked with climatic change. ...
Article
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Fire has been part of the global ecosystems for the past 420 million years (Bowman et al. 2009), although controlled human use seems to have occurred only in the past 400,000 years ago. Discriminating between natural and anthropogenic fires in the archaeological and paleoecological records has been a hot topic, particularly in Australian fire studies over the past 20 years
... 296 46,98,219,250,282 Individual grasstrees were lit as signal fires. 344 The leaves were used to cut meat. 282 Xanthorrhoea were also an Aboriginal food source. ...
... The assessment of the interval between burns is an important tool to detect human interference. Hassell and Dodson's (2003) charcoal-based study of the fire history of southwest Western Australia provides an example. They measured charcoal deposition over time during the Pleistocene and Holocene and found a decrease in the length of the fire intervals during the Holocene that cannot be ascribed to natural changes in fire-prone vegetation linked with climatic change. ...
Article
Full-text available
Archaeological indications for off-site burning by late Pleistocene and early Holocene hunter-gatherers present intransigent interpretive problems; by contrast, burning practices by recent hunter-gatherers are well documented. Here, we present a systematic global inventory of extant burning practices—including the reasons for burning and the environmental setting of firing activities—and also discuss their visibility in the archaeological record. This inventory is based on ethnographic and historical texts. In historical times, off-site fire was used for a wide range of purposes, irrespective of age and gender, with significant advantages for its producers. While the reasons given for burning can vary between individuals, in the longer term, many hunter-gatherer firing practices created more mosaic types of environments than would have occurred naturally. The historical visibility of hunter-gatherer burning activities contrasts with the relative invisibility of such practices in the contemporary archaeological record, highlighting the difficulty of analyzing past use of fire. On the basis of its ethnographic importance, we suggest that diverse off-site fire use is as old as the regular use of fire. New multiproxy data from well-sampled sequences, analyzed at a local scale, is needed to test this hypothesis.
... This sophistication included varying management of fire in relation to the phenology and availability of resources. Where resource abundance was low, or independent of fire, vegetation may have been burnt less frequently or not at all (Hassell & Dodson, 2002). Historical records indicate extensive use of fire, in the sense that fire was often observed, but the spatial extent and pattern of these fires, or which parts of the landscape were burnt (or not burnt) is less completely described. ...
... Fire and conservation management is particularly complex in fragmented peri-urban areas, where there are multiple, often conflicting, objectives to fire management (Burrows and McCaw, 2013;Driscoll et al., 2010;Penman et al., 2011). Southwestern Australia has been occupied by humans for at least 30,000 years, and Aboriginal burning patterns, that are predicted to have created a patchy mosaic of post-fire vegetation, are thought to have been in place for the past 5000-7000 years (Hassell and Dodson, 2003). Fire is regularly used as a contemporary landscape management tool to reduce wildfires, although the application of prescribed burning is debated (Burrows and McCaw, 2013;Enright and Fontaine, 2014). ...
... A Mediterranean-type climate and the accumulation of live and dead vegetation (fuel) make the forest region of southwest Australia prone to fire. While the pre-European fire regime is not well understood, there is evidence of fire occurrence in south-west ecosystems that pre-dates the arrival of humans by thousands of years (Hassell and Dodson 2003) and evidence of regular burning of parts of the forest by Nyoongar Aborigines (Hallam 1975;Abbott 2003;Lamont and others 2003). Consequently, the vegetation displays fire adaptive traits typical of fire prone environments in other parts of the world, such as the ability to resprout after fire, serotiny, thick protective bark and germination cued by heat and smoke (Christensen and Kimber 1975;Bell and others 1989;Dixon and others 1995;Burrows and Wardell-Johnson 2003). ...
Article
Full-text available
Regular fuel reduction burning is an important management strategy for reducing the scale and intensity of wildfires in southwest Australian native forests, but the long term effects of this on tree and stand growth are not well understood. Five fire treatments, including application of frequent and infrequent low intensity burns, and 25 years of fire exclusion, were applied to small (4 ha) experimental plots in a low rainfall mixed jarrah (Euca-lyptus marginata) and marri (Corymbia calophylla) forest to investigate the effects of these treatments on tree stem diameter growth, stand basal area increment and tree mortality. Mean tree stem growth measured over 20 years was lowest in the long unburnt treatment compared with the burn treatments, although surface soil nutrient levels were generally higher in the unburnt treatment, suggesting these sites may be moisture limited. There was no clear pattern of the effects of the burn treatments, including the number of fires and the interval between fires, on tree stem growth, stand basal area increment, crown health or mortality. These factors were strongly influenced by dominance condition, with dominant and co-dominant trees growing most and suppressed trees growing least and experiencing the highest mortality levels. There was no evidence of deteriorating tree or stand health that could be attributed to either regular low intensity burning or to a long period (25 years) of fire exclusion.
... A Mediterranean-type climate and the accumulation of live and dead vegetation (fuel) make the forest region of southwest Australia prone to fire. While the pre-European fire regime is not well understood, there is evidence of fire occurrence in south-west ecosystems that pre-dates the arrival of humans by thousands of years (Hassell and Dodson 2003) and evidence of regular burning of parts of the forest by Nyoongar Aborigines (Hallam 1975;Abbott 2003;Lamont and others 2003). Consequently, the vegetation displays fire adaptive traits typical of fire prone environments in other parts of the world, such as the ability to resprout after fire, serotiny, thick protective bark and germination cued by heat and smoke (Christensen and Kimber 1975;Bell and others 1989;Dixon and others 1995;Burrows and Wardell-Johnson 2003). ...
... A Mediterranean-type climate and flammable vegetation have ensured that the jarrah and karri forests of south-western Australia have evolved with fire over thousands of years (Hassell and Dodson 2003). ...
... Such a bleak outlook is much less applicable to the kwongan of the Coolgardie Interzone. Here, beyond the clearing line, the landscape is largely intact and evolutionary processes are expected to continue, despite the depletion of the critical weight range mammal fauna (Burbidge & McKenzie, 1989) and presumed changes in the historic fire regimes (Hassell & Dodson, 2003;Parsons & Gosper, 2011). ...
Chapter
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The kwongan flora of south-western Australia is known for its remarkable diversity and endemism, and the region is recognised as one of the world's vascular flora biodiversity hotspots. This recognition is based not only on high floristic richness, but also on the number and magnitude of a range of threatening processes. Currently 2004 plant taxa are listed as rare and poorly known, and 304 as threatened. This accounts for nearly 30% of the south–west flora.
... Such a bleak outlook is much less applicable to the kwongan of the Coolgardie Interzone. Here, beyond the clearing line, the landscape is largely intact and evolutionary processes are expected to continue, despite the depletion of the critical weight range mammal fauna (Burbidge & McKenzie, 1989) and presumed changes in the historic fire regimes (Hassell & Dodson, 2003;Parsons & Gosper, 2011). ...
... Some of the earliest hominids occurred in South Africa and early African Homo species expanded into the Mediterranean Basin nearly a million years ago, with European populations following the retreat and advance of glaciers. From its African origins, Homo sapiens expanded through Europe and Asia, eventually reaching Australia by 40,000-60,000 years ago and the Americas by about 12,000 BP (Fagan, 2003;Hassell & Dodson, 2003). Early human populations in med-regions engaged in hunting, fishing, and gathering activities, up to the time of European conquest in the Americas, southern Africa, and Australia. ...
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We reviewed the literature on the effects of land use changes on mediterranean river ecosystems (med-rivers) to provide a foundation and directions for future research on catchment management during times of rapid human population growth and climate change. Seasonal human demand for water in mediterranean climate regions (med-regions) is high, leading to intense competition for water with riverine communities often containing many endemic species. The responses of river communities to human alterations of land use, vegetation, hydrological, and hydrochemical conditions are similar in mediterranean and other climatic regions. High variation in hydrological regimes in med-regions, however, tends to exacerbate the magnitude of these responses. For example, land use changes promote longer dry season flows, concentrating contaminants, allowing the accumulation of detritus, algae, and plants, and fostering higher temperatures and lower dissolved oxygen levels, all of which may extirpate sensitive native species. Exotic species often thrive in med-rivers altered by human activity, further homogenizing river communities worldwide. We recommend that future research rigorously evaluate the effects of management and restoration practices on river ecosystems, delineate the cause–effect pathways leading from human perturbations to stream biological communities, and incorporate analyses of the effects of scale, land use heterogeneity, and high temporal hydrological variability on stream communities.
... 296 46,98,219,250,282 Individual grasstrees were lit as signal fires. 344 The leaves were used to cut meat. 282 Xanthorrhoea were also an Aboriginal food source. ...
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Cite this document as: Borsboom, A.C. (2005) Xanthorrhoea: A review of current knowledge with a focus on X. johnsonii and X. latifolia, two Queensland protected plants-in-trade. Environmental Protection Agency, Queensland. Disclaimer The author in preparing this document has taken all reasonable care. Analysis and interpretation of information obtained and resultant recommendations and conclusions are those of the author. Statements made do not necessarily reflect Government or Agency policy or opinion, and do not commit the Government or the Environmental Protection Agency to any action. The Queensland Government accepts no liability for any external decisions or actions taken on the basis of this document. Persons external to the Environmental Protection Agency should satisfy themselves independently and by consulting their own professional advisors before embarking on any proposed course of action.
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Protection of biodiversity, human assets, and cultural heritage pose significant challenges to contemporary planning of bushfire mitigation activities. Current mitigation approaches are not always appropriate, and mismanagement is a source of distress for Indigenous peoples. Increased understanding of Indigenous fire knowledge and increased Indigenous participation may provide insight into more appropriate and inclusive land management for fire mitigation. We analysed contemporary Noongar and Western fire practitioner approaches within an Indigenous fire knowledge (IFK) framework to explore knowledge and aspirations for small reserves in the Southwest Australian Floristic Region (SWAFR) global biodiversity hotspot. We recorded an extensive knowledge base, characterised by a highly nuanced approach to burning, held by the Noongar coauthors. We explore potential approaches to applying this knowledge to build collaborative fire mitigation strategies with mutually beneficial outcomes for biodiversity, cultural heritage, and human assets.
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This essay reconstructs defensive/offensive mechanisms of Aboriginal communication networks and presents historical examples of their application as a means of resistance during Australia’s frontier wars. The principal focus is on smoke-signalling systems, especially in Queensland.
Chapter
Many people have called for Integrated Fire Management that effectively harnesses the power of fire to achieve land management goals. Often this includes using fire, and certainly, it involves managing both short- and long-term effects of fire informed by an understanding of both people and place. In eight case studies from around the globe, local experts describe successful variants of integrated fire management. Their stories illustrate innovative, proactive approaches to managing fires and the ecosystems, including people, in which those fires occur. Integrated Fire Management is different in each location, but it is always focused on long-term effectiveness in meeting strategic objectives, and the most effective practitioners are constantly listening, learning, and adapting while working with many different people. In this way, the case studies illustrate that effective fire management is informed by the scientific principles you’ve learned in prior chapters of our book, Fire science from chemistry to landscape management, but also depends on being flexible and adaptive to local and changing conditions. Such management uses fire as one of the tools to increase the benefits of fire while limiting the negative effects of fire in achieving social-ecological ecosystem goals strategically.
Chapter
Australia and New Zealand are home to a remarkable and unique assemblage of flora and fauna. Sadly though, by virtue of their long isolation, and a naïve and vulnerable biota, both countries have suffered substantial losses to biodiversity since European contact. Bringing together the contributions of leading conservation biologists, Austral Ark presents the special features and historical context of Austral biota, and explains what is being conserved and why. The threatening processes occurring worldwide are discussed, along with the unique conservation problems faced at regional level. At the same time, the book highlights many examples of conservation success resulting from the innovative solutions that have been developed to safeguard native species and habitats in both New Zealand and Australia. Austral Ark fills an important gap regarding wildlife gains and declines, and how best to take conservation forward to keep this extraordinary area of the world thriving.
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Exploring the role of fire in each of the five Mediterranean-type climate ecosystems, this book offers a unique view of the evolution of fire-adapted traits and the role of fire in shaping Earth's ecosystems. Analyzing these geographically separate but ecologically convergent ecosystems provides key tools for understanding fire regime diversity and its role in the assembly and evolutionary convergence of ecosystems. Topics covered include regional patterns, the ecological role of wildfires, the evolution of species within those systems, and the ways in which societies have adapted to living in fire-prone environments. Outlining complex processes clearly and methodically, the discussion challenges the belief that climate and soils alone can explain the global distribution and assembly of plant communities. An ideal research tool for graduates and researchers, this study provides valuable insights into fire management and the requirements for regionally tailored approaches to fire management across the globe. © J. E. Keeley, W. J. Bond, R. A. Bradstock, J. G. Pausas and P. W. Rundel 2012.
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Kings Park bushland is an urban remnant of predominantly mixed Eucalyptus-Allocasuarina--Banksia mediterranean climate-type woodland in southwestern Australia. This paper presents the results of one of the longest quantitative comparisons on multispecies temporal differences in the Southern Hemisphere. In 1939, the locations of individuals of 13 dominant native tree and shrub species were mapped in 126 transects in a 60 ha portion of the bushland. Observations of the same transects were undertaken in 1999, and the temporal differences in the presence of the same 13 species compared both with univariate and multivariate analyses. There have been substantial changes in vegetation structure and species dominance within the plant community in the 60 years period. In the woodland canopy, there has been an increase in Eucalyptus gomphocephala, E. marginata, Corymbia calophylla and Allocasuarina fraseriana and a decline in once dominant Banksia species. In the mid-storey there have been increases in the density of Dryandra sessilis and Acacia saligna. The changes in structure and species dominance may be considered as changes between different community variants that all occur in the vegetation of the Swan Coastal Plain. The main factors that may be responsible for vegetation change are weed invasion, changed fire regime and seed predation of some species. Disturbances beyond the control of managers (such as wildfire) have altered the composition of the vegetation. However, changes in management procedures in the urban reserve, such as weed removal with herbicides and cessation of fuel reduction burning have also been successful in altering the prominence of some native plant species in the Park. The outcomes of this study indicate that in urban remnants of once natural ecosystems the relative dominance of species may change in response to changes in disturbance regime and hence recruitment cues and this may have important consequences in terms of managing and conserving fauna and flora assemblages, including rare species, in reserves.
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We use multiple lines of evidence, including palaeo-environmental, ecological, historical, anthropological and archaeological, to investigate pre-European fire regimes in Australia, with particular focus on the extent to which the use of fire by Aboriginal peoples since their colonisation of the continent at least 45,000 years ago has impacted on the Australian biota. The relative roles of people and climate (including past climate change) as agents driving fire regime are assessed for the major climate–vegetation regions of the continent. Both historical accounts and evidence from current land-use practices in some areas support the argument that Aboriginal peoples used fire as a land management tool. Evidence for pre-European fire regimes suggests that while large areas of savanna woodlands in northern Australia, and dry forests and woodlands in temperate southern Australia, were subjected to increased fire under Aboriginal land management; others were not. Areas where fire regime was controlled primarily by ‘natural’ climate-fuel relationships probably included those that were difficult to burn because they were too wet (e.g. rainforests), fuel levels were usually too low (e.g. desert and semi-arid rangelands), or resource availability was low and did not support other than transient human occupation (e.g. some shrublands). Scientific studies suggest that many fire-sensitive woody species would decline under more frequent burning, so that the use of a small patch size, frequent fire regime – such as may have existed over large parts of Australia in the pre-European (Aboriginal occupation) period – may have harmful biodiversity conservation outcomes if instituted without careful consideration of individual ecosystem and species requirements.
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