Abstract
Context Increases in fire frequency, intensity and extent are occurring globally. Relative to historical, Indigenous managed conditions, contemporary landscapes are often characterised by younger age classes of vegetation and a much smaller representation of long-unburnt habitat.ObjectivesWe argue that, to conserve many threatened vertebrate species in Australia, landscape management should emphasise the protection of existing long-unburnt patches from fire, as well as facilitate the recruitment of additional long-unburnt habitat, while maintaining historically relevant age distributions of more recently burned patches.MethodsWe use a range of case studies and ecosystem types to illustrate three lines of evidence: (1) that many threatened vertebrate species depend on mid- to late-successional ecosystem attributes; (2) disturbance to long-unburnt habitat tends to increase risk of future disturbance and ecosystem collapse; and (3) contemporary landscapes exhibit a range of characteristics that differ to historical conditions and require context-specific management.ConclusionsIt is crucial that we adequately consider the implications of altered contemporary landscapes for management activities that aim to conserve threatened vertebrates. Contemporary landscapes often lack a range of critical structural and compositional components typical of late-successional habitat that are required for the persistence of threatened vertebrates. We need to shift towards strategic, objective-driven approaches that identify and protect long-unburnt habitats and promote their recruitment to enable recovery of many declining and threatened species.
Highlights
Ecological disturbance regimes are being disrupted worldwide, with changing fire regimes a growing issue (Webster et al 2005; Seidl et al 2017; ; Bowman et al 2020)
Since 1979, there has been a global increase of 19% in mean fire weather season length, and a doubling of the percentage of global vegetated area experiencing long fire weather seasons (Jolly et al 2015)
Frequency, intensity, and extent of fire events varies substantially between different ecosystem types and vegetation communities, relative increase in these factors is a common theme worldwide (Bowman et al 2020). These changes can be considered as a shift in the frequency distribution of fire regime attribute values across the landscape (Fig. 1), which has flow-on effects to structural and functional characteristics at a landscape scale
Summary
Ecological disturbance regimes are being disrupted worldwide, with changing fire regimes a growing issue (Webster et al 2005; Seidl et al 2017; ; Bowman et al 2020). In south-western Australia, four threatened bird species (the western ground parrot Pezoporus flaviventris, western bristlebird Dasyornis longirostris, noisy scrub-bird Atrichornis clamosus, and black-throated whipbird Psophodes nigrogularis) are restricted to scattered remaining patches of vegetation communities dominated by heaths, sedges, and low eucalypts (Smith 1985) These birds rely on relatively moderate (5–10 years post-fire) to long (10+) intervals between fire events for population persistence (Meredith et al 1984; Smith 1991, 1996; Burbidge et al 2007), with more frequent fire causing the loss of functional and structural attributes that individuals rely on for food resources and protection from predators (Burbidge 2003). Many species may be adapted to survive the initial fire event (Nimmo et al 2021; Jolly et al 2022), post-fire survival can be significantly reduced by increased exposure to predators (Leahy et al 2016; Wintle et al 2020) and reductions in resource availability (Williams et al 2010; Lindenmayer et al 2011b)
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