Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p18
Version: federal_register_of_legislation:F2024L00270
Segment Type: other
Provision Reference: 
Character Range: 48942–52073

conservation management
    * Population and habitat monitoring has provided a vital contribution to understanding this complex system, and existing monitoring programs should be retained and expanded to including all relevant habitat types, forest ages and throughout all of the species' range. Existing monitoring also provides information on responses to some management, but further enhancements to more comprehensively assess management effectiveness are required.

3.3.3             Subpopulation structure and genetic variation
Leadbeater's possum comprises two distinct genetic groups, with marked and long-standing distinction in genetic composition between the small lowland subpopulation at Yellingbo and all other (montane ash forest and sub-alpine (snow gum) woodland) subpopulations (Hansen et al. 2005; Hansen and Taylor 2008; Zilko 2021). The former is considered an evolutionarily significant unit (ESU) as it is the last surviving remnant (relict) of an otherwise extinct genetic unit, that has historically been, and remains, isolated from others (Hansen and Taylor 2008).
Genetic sampling has been more limited across the highland range. The only location with substantial sampling effort is Lake Mountain, where samples were collected from 159 individuals in 2006 to 2007 (Hansen and Taylor 2008; Hansen et al. 2009). However, small numbers of samples are available from most parts of the species' range following field sampling undertaken by Zoos Victoria in 2018 and 2019 (Zilko 2021).
The Yellingbo population is inbred (Hansen et al. 2009; Zilko et al. 2020), with recent analyses revealing inbreeding depression (Zilko et al. 2020, 2021). Sub-structuring has also been reported indicating that this can occur over small spatial scales and the species may be highly sensitive to habitat fragmentation (Hansen et al. 2009; Zilko et al. 2020). A genetic rescue strategy has been devised and is being implemented based on managed levels of gene-pool mixing between lowland and highland Leadbeater's possums.
Previous research indicated that in the Central Highlands populations are 'remarkably genetically diverse', with evidence of ongoing gene flow (indicating effective dispersal) across much of this range, although with some contrary evidence of recent disruption of gene flow for some sites (for example, Powelltown), probably due to habitat fragmentation (Hansen et al. 2009). Subpopulation structuring has recently been re-examined in the Central Highlands (Zilko 2021) and revealed four distinct genetic groups in the highlands: Northern (encompassing Snob's Creek, Mt Bullfight, Lake Mountain, Arnold Gap, and Marysville), Central (Warburton, Donna Buang, and Ben Cairn), Southern (Powelltown), and Eastern (Baw Baw National Park and Toorongo Plateau). This suggests contemporary isolation of the four groups, highlighting the need to reconnect populations to avoid further erosion of genetic diversity and fitness decline (as has been documented for the lowland population).
The southern genetic group (Powelltown population) appears to be most vulnerable based on its size. It also was inferred to