Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p20
Version: federal_register_of_legislation:F2024L00270
Segment Type: other
Provision Reference: 
Character Range: 54659–57727

from at risk populations (for example, lowland) for restoring genetic diversity in the future.

3.4                 Habitat

3.4.1             Key habitat features
Broadly, the key habitat features required by Leadbeater's possum are (1) suitable (large) hollows for denning and breeding, at a density that allows for multiple den sites within any single colony home range; (2) vegetation structure in the form of a sub-canopy or midstorey layer of more of less continuous or interconnecting foliage cover (to facilitate the possum's movement and foraging) (Lindenmayer 1996b); and (3) forest composition that includes dominance of smooth-barked eucalypts (especially species with some loose or decorticating bark that provides shelter for invertebrate prey) (Lindenmayer 1996b; Harley 2004a,c), often with a midstorey of gum-producing wattle (Acacia spp.) species in montane ash (Smith et al. 1985; Smith and Lindenmayer 1988; Lindenmayer et al. 1991b).
In subalpine woodland the presence of mountain tea tree (Leptospermum grandifolium) is a key feature of suitable habitat, as is the presence of Melaleuca spp. or Leptospermum spp. in lowland swamp forest. Additionally, Leadbeater's possums construct a large nest (inside hollows) made of shredded fibrous bark from eucalypts or paperbark, and the occurrence of trees with such fibrous bark in the home range is also required (Smith and Lindenmayer 1988; Harley 2004b).
Suitable hollows are closely associated with tree age and size. Hollows used typically have large internal dimensions (approximately 30 cm diameter) (Smith and Lindenmayer 1988) and occur almost exclusively in large old trees (Lindenmayer et al. 2013b; Lindenmayer et al. 2013c), that are 190–450 years old (Smith and Lindenmayer 1988; Lindenmayer et al. 2015a). In contrast, the dense midstorey preferred by Leadbeater's possum often occurs in young regenerating forests and optimal habitat occurs in multi-aged forest where the large trees, dead or living, provide hollows, and regenerating vegetation provides food and movement pathways (Lindenmayer et al. 1990b).
Habitat suitability and occupancy is also influenced by broader spatial landscape context, around individual nest trees (Lindenmayer et al. 1990a) and around a forest site. The likelihood of persistence of Leadbeater's possum in any habitat patch increases substantially with increasing patch area (McCarthy and Lindenmayer 2000; Lindenmayer and McCarthy 2006). At least in montane ash habitat, there is little use of narrow habitat strips through recently harvested areas (Lindenmayer et al. 1993b). Three years after the 2009 bushfires, Leadbeater's possums were detected in 16% of isolated unburnt mountain ash forest patches with the smallest occupied patch being 10 ha (Lumsden et al. 2013). Small numbers of individuals also persisted in unburnt linear refuges of sub-alpine woodland at Lake Mountain and Mt Bullfight (D. Harley and J. Antrobus, pers. comm.). While the pattern of recolonisation is still not fully understood, the rapid recolonisation throughout some of