Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p38
Version: federal_register_of_legislation:F2024L00270
Segment Type: other
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Character Range: 104211–107204

in climate and fire regimes (McKenzie 2002; Worth et al. 2014). Since European colonisation fire management practices (and hence fire regimes) have changed, including in montane ash forests, and along with cumulative impacts of timber harvesting have led to decline in the extent, quality and connectivity of montane ash habitat suitable for Leadbeater's possum (Lindenmayer et al. 2008; Lindenmayer et al. 2011a; Burns et al. 2015; Taylor and Lindenmayer 2020).

4.2                 Current threatening processes
The ongoing reduction in the extent, quality and connectivity of suitable habitat has resulted in, and is projected to continue to cause, ongoing decline in population size and conservation status (TSSC 2019). This has occurred, and continues to occur, through a range of drivers:
    * impacts of severe fire and changes in fire regime;
    * timber harvesting over many decades – noting that timber harvesting by the Victorian government on state land will cease 1 January 2024. Coverage in this plan is restricted to the legacy impacts of historical harvesting;
    * reduction in the abundance of hollow-bearing trees;
    * eucalypt dieback and altered hydrology (for the lowland subpopulation); and
    * lack of genetic diversity (for the lowland swamp subpopulation).
In turn, ongoing habitat loss has resulted in, and will continue to cause, some fragmentation (and thus reduced genetic diversity and viability) of subpopulations in the Central Highlands.
Current and projected climate change is likely to exacerbate the ongoing reduction in habitat extent and quality, particularly through its impacts on the severity and frequency of bushfires (Lindenmayer et al. 1991d; Williams et al. 2009; Keenan and Nitschke 2016), and hence on forest structure, tree age distribution and hollow availability (Keenan and Nitschke 2016). Leadbeater's possum occurs in a cool-climate region and is likely to be susceptible to increasing temperatures and extreme heat events.
The impact of predation by cats and foxes on population condition, particularly in disturbed habitat (for example, following bushfire), is poorly understood, but potentially problematic.

4.2.1             Impacts of severe fire and changes in fire regime
Fire is a direct and indirect threat to Leadbeater's possum. Few if any Leadbeater's possums survived in areas burnt by bushfires in 2009, regardless of fire severity (Lindenmayer et al. 2013c; Lumsden et al. 2013). Marked loss was also reported for Leadbeater's possum in snow gum woodlands (Harley 2016). Possums were also less abundant on unburned sites where the surrounding landscape has been burned (Lindenmayer et al. 2013c; Lindenmayer et al. 2015b). However, about 8–10 years post-fire some of the areas burnt in 2009 have been recolonised, coinciding with development of a dense cover of wattle and other small trees. This re-establishment is likely to be contingent on some hollow-bearing trees remaining in the burnt landscape, or being in