Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p23
Version: federal_register_of_legislation:F2024L00270
Segment Type: other
Provision Reference: 
Character Range: 62910–65806

also provide suitable foraging habitat if there are sufficient suitable nesting sites within the regrowth or in adjacent areas (Smith et al. 1985; Nelson et al. 2015; Keith et al. 2016; Nelson et al. 2017). A recent study reported that the abundance of Leadbeater's possum in a set of sites with large hollow-bearing trees retained within timber harvesting regrowth from the 1960 to the 1980s (prior to the commencement of clear felling) was significantly higher than their abundance in 1939 regrowth or mixed aged forest, and not significantly different from the abundance in old growth (Keith et al. 2016). Similarly, surveys of younger timber harvesting regrowth (1978 to 2000) showed high detection rates of Leadbeater's possum compared to older age classes (Nelson et al. 2015; Nelson et al. 2017).
In the post-fire (bushfire or regeneration burns after harvesting) successional cycle, the biomass of wattles increases, peaks and then declines as they senesce and die (typically 60–100 years after disturbance), and stags gradually collapse (Lindenmayer et al. 2012). Habitat may then be of diminishing suitability to provide for all Leadbeater's possum habitat requirements, until the regrowth cohort of eucalypts becomes old enough to form suitable hollows for Leadbeater's possum (typically well over 100 years), however, by that time since disturbance, the forest lacks the dense wattle midstorey component required by Leadbeater's possum (Baker et al. 2022).
Bushfire is a key driver of habitat suitability in montane ash forests (and in other habitats used by Leadbeater's possum with the exception of sub-alpine woodland). Frequent, high intensity or extensive fires may reduce the availability of hollow trees. Recent estimates indicate that the extent of mountain ash forest that is 'old-growth' has declined from an estimated minimum 47,000 ha at the time of European settlement to approximately 1700 ha now, mostly in very small fragments (Lindenmayer et al. 2014a; Burns et al. 2015; Lindenmayer et al. 2015a). The extent of old-growth in alpine ash forests is even less (0.37% of its extent) (Lindenmayer et al. 2014a).
Habitat suitability at any site is typically related to the co-occurrence at that site of sufficient hollows (for nesting) and adequate midstorey cover (for movements and feeding), but these attributes may not always co-occur at the site itself – Leadbeater's possums can occur in an area in which there is a close juxtaposition of habitat that provides nesting hollows but not suitable foraging habitat with habitat that provides suitable foraging habitat but few nesting hollows (Lumsden et al. 2013; Nelson et al. 2017). However, further research is required to understand the extent to which Leadbeater's possum can use such spatial variation, and if there are negative consequences from using separate foraging and nesting areas. In lowland swamp forest