Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1890/ES14-00145.1 |
Scale-dependent thresholds in the dominant controls of wildfire size in semi-arid southwest Australia | |
O’Donnell, A. J.1,2; Boer, M. M.1,2; McCaw, W. L.2,3; Grierson, P. F.1,2 | |
通讯作者 | O’Donnell, A. J. |
来源期刊 | ECOSPHERE
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ISSN | 2150-8925 |
出版年 | 2014 |
卷号 | 5期号:7 |
英文摘要 | We aimed to characterize the size distribution of naturally occurring wildfires and to determine how fuel characteristics influence wildfire size in a vegetation mosaic of shrublands and woodlands in semi-arid southwest Australia. The shape of frequency-size distributions of fires can be used to elucidate shifts in the dominant drivers or constraints of fire size. We modeled the cumulative frequency-size distribution of wildfires in southwest Australia using a segmented linear model with two break points. Three fire size categories were defined by the break points of the segmented model: "small’’ (<2,286 ha), "medium’’ (2,286-41,020 ha), and "large’’ fires (>41,020 ha). Break points were interpreted as thresholds in fire size that may represent shifts in the dominant controls of fire spread. We tested whether the influence of fuel characteristics on fire spread varied among fire size categories by comparing the composition of vegetation types and fuel ages among burnt and adjacent unburnt areas using selection ratios (omega(chi)). Small and medium fires burnt shrub-dominated vegetation types in proportion to their availability (omega(chi) approximate to 1), but tended to burn smaller proportions of sparsely-vegetated woodlands (omega(chi) < 0.62). In contrast, large fires tended to burn woodlands in proportion to their availability (omega(chi) approximate to 1). Young fuels (<20 years) were under-represented in burnt areas regardless of fire size (omega(chi) < 0.62), while older fuels (<30 years) burnt in proportion to their availability (omega(chi) approximate to 1). Fire size in semi-arid southwest Australia is generally limited by fuel mass in recently burnt areas and by fuel continuity in sparsely vegetated woodlands. However, following unusually wet years and subsequent growth of ephemeral plants, fuels in woodland vegetation likely become spatially continuous and capable of supporting the spread of large fires. |
英文关键词 | eucalypt woodland fire size distribution fuel age inter-annual climate variability mallee Pareto model power law segmented model selection ratio shrubland vegetation type |
类型 | Article |
语种 | 英语 |
国家 | Australia |
收录类别 | SCI-E |
WOS记录号 | WOS:000345096600016 |
WOS关键词 | SELF-ORGANIZED CRITICALITY ; FIRE REGIMES ; FOREST-FIRES ; CLIMATE-CHANGE ; VEGETATION STRUCTURE ; SOUTHERN AUSTRALIA ; SPATIAL CONTROLS ; SHRUBLANDS ; FUEL ; LANDSCAPES |
WOS类目 | Ecology |
WOS研究方向 | Environmental Sciences & Ecology |
来源机构 | University of Western Australia |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/181750 |
作者单位 | 1.Univ Western Australia, Sch Plant Biol, Ecosyst Res Grp, Crawley, WA 6009, Australia; 2.Bushfire Cooperat Res Ctr, East Melbourne, Vic 3002, Australia; 3.Dept Pk & Wildlife, Div Sci, Manjimup, WA 6258, Australia |
推荐引用方式 GB/T 7714 | O’Donnell, A. J.,Boer, M. M.,McCaw, W. L.,et al. Scale-dependent thresholds in the dominant controls of wildfire size in semi-arid southwest Australia[J]. University of Western Australia,2014,5(7). |
APA | O’Donnell, A. J.,Boer, M. M.,McCaw, W. L.,&Grierson, P. F..(2014).Scale-dependent thresholds in the dominant controls of wildfire size in semi-arid southwest Australia.ECOSPHERE,5(7). |
MLA | O’Donnell, A. J.,et al."Scale-dependent thresholds in the dominant controls of wildfire size in semi-arid southwest Australia".ECOSPHERE 5.7(2014). |
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