Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p33
Version: federal_register_of_legislation:F2024L00270
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Character Range: 90346–93219

23; males – mean 495 m, range 105–1460 m, n = 33) (Harley 2005). Dispersal into established colonies is more common than new colony formation in unoccupied habitat (Harley 2005). Dispersal is strongly tied to the onset of reproduction, and hence animals are likely to be searching for breeding opportunities when dispersing (Harley 2005; Harley et al. 2005). There is a biased adult sex ratio, of about three males per female in montane ash forest (Smith 1984b; Lindenmayer 1996b), whereas the adult sex ratio is more variable in lowland swamp forest (Harley 2005).

3.7                 Demography and breeding biology

3.7.1             Demography and reproduction
Longevity is 5–8 years in the wild, with the maximum age recorded being ten years (Smith 1984b; Lindenmayer and McCarthy 2006; D. Harley, unpublished data). Age at first breeding is two years (Smith 1980; Lindenmayer et al. 1993d; Lindenmayer and Possingham 1995a, 1995c; Harley and Lill 2007).
Some demographic characteristics vary among subpopulations in different habitats: for example, the mean reproductive life in adult females in a montane ash forest site was reported to be 1.6 years, but at least 3.3 years at Yellingbo (Smith 1984b; Harley 2005; Smith and Harley 2008).
The reproductive rate is relatively low, with a litter size of 1–2 young per breeding female (and hence per colony) with two litters per year (Harley and Lill 2007). Reproductive success is probably related to food supply (Smith 1984b). Breeding is seasonal in montane ash forests, with most births occurring in distinct peaks in May and November (Smith 1984b), but breeding at Yellingbo occurs year-round (Harley 2005; Harley and Lill 2007; Smith and Harley 2008). Young remain in the pouch for 80–93 days (Smith 1980; Harley 2005; Smith and Harley 2008), emerge from the nest at about 111 days, and remain in the natal territory for 7–14 months (females) and 11–26 months (males) (Smith 1980, 1984b; Menkhorst and Lumsden 1995). In lowland swamp forest, some young have been recorded remaining in their natal territories for far longer periods (D. Harley, unpublished data). Only about 20% of young at Yellingbo survived to acquire breeding status within established groups with most animals dispersing at 20–36 months of age (Harley 2005; Harley et al. 2005).

3.7.2             Captive breeding
The first captive breeding of Leadbeater's possums was undertaken by Des Hackett in the early 1970s from animals captured in the Central Highlands (Preuss 2006). Several zoos around the world subsequently bred the species but this program was not integrated into any broader conservation management strategy. With no designated outlet for young bred in captivity, adults were segregated to reduce breeding and the captive population ultimately aged and declined (Harley and Lowry 2013; Steventon et al. In review).
In 2012, Zoos