Document ID: chunk:federal_register_of_legislation:F2022L00555:body:0:p48
Version: federal_register_of_legislation:F2022L00555
Segment Type: other
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Character Range: 157436–160359

capacity of a given landscape, making populations more susceptible to extinction (the small population paradigm, Caughley 1994)
    * loss of connectivity reduces natural movement such as the ability of individuals to disperse safely, therefore reducing gene flow and healthy levels of genetic exchange among adjacent populations
    * fragmentation can increase mortality during movements made through the intervening matrix, for example, by dog attack and car strikes.
These landscape effects also disrupt natural processes which sustain Koala habitat, impacting the mortality, recruitment, nutrition, and climate adaptation of their food and shelter trees.

Eucalypt regrowth forest showing E. moluccana and C. citrioddora. The high elevation forest together with heavy summer rainfall makes such forest areas potential climate refugia for the listed Koala. Bluff Forest Reserve, far north Qld. Image: © Don Franklin.

19. Direct threats

19.1 Climate change
Climate change is a serious threat to Koala persistence across much of its distribution (see section 21.3). By 2030, more than 20% of listed Koala habitat is likely to be seriously impacted by climate change under high global emissions scenarios (Adams-Hosking et al. 2011a; Briscoe et al. 2016; Table 3). Under current climate trajectories, by 2100 near-normal and wet years will become much less frequent across much of the distribution of the Koala and the frequency of extreme drought and heatwaves is predicted to increase by 2100 (CSIRO and BOM 2015; Herold et al. 2018). The loss of climatically suitable habitat as a result of climate change may outpace losses from land use change within the next decade.
Drought and heatwaves leading to increased mortality are the predominant means by which climate change will impact Koalas (section 29). Recent rapid and substantial declines of Koalas in regions west of the Great Dividing Range from drought and heatwave are attributed to climate change (Seabrook et al. 2011; Lunney et al. 2017). These impacts are not confined to inland areas, in coastal New South Wales, climate change is adding to the cumulative impacts on already stressed populations (Lunney et al. 2014).
Most western populations are at greatest and most urgent risk from climate change and are likely to decline severely in the next decade and become extinct by 2070 unless climate change is halted (Appendix 3). Under high global emissions scenarios, there is a risk of widespread climate-driven extinction of Koalas by 2070 in most western populations including the Brigalow Belt, Mulga Lands, Mitchell Grass Downs, Darling Riverine Plains and Desert Uplands bioregions (Adams-Hosking et al. 2011a; Briscoe et al. 2016; McAlpine et al. 2015; Appendix 3). These populations may have traits and underlying genetics that mean they are better adapted to drought and heatwaves than are other Koala populations, and hence they are important to