Document ID: chunk:federal_register_of_legislation:F2024L00006:reg:3:p26
Version: federal_register_of_legislation:F2024L00006
Segment Type: reg
Provision Reference: reg 3 (pt 26/58)
Character Range: 74481–77565

more extreme maximum temperatures, and occurring more frequently over many regions of Australia, including south-eastern Australia (Perkins-Kirkpatrick et al. 2016; Evans et al. 2017; Herold et al. 2018; BOM & CSIRO 2020). Heatwaves also exacerbate drought, which in turn can also increase bushfire risk (BOM & CSIRO 2020). Birds are also vulnerable to extreme heatwaves that overwhelm their physiological limits (McKechnie et al. 2012).

 Climate change is expected to intensify current threats to the Eastern Bristlebird. Climate change effects that may impact the Eastern Bristlebird include 'changes in vegetation caused by changes in temperature and rainfall (including increased weed and pathogen invasion), reduced food source, increased occurrence of extreme events such as droughts and fires and possible reduction in reproductive success.

 Eastern Bristlebirds have been identified as a species that is likely to be exposed to increases in the frequency and intensity of fires arising from climate change (Garnett et al. 2013). Climate change may reduce the availability of suitable Eastern Bristlebird habitat. For the northern population, enhanced levels of carbon dioxide may increase woody plants within grassy ecosystems (DPIE 2018) and birds have been observed moving into gullies during long hot summers (Stone et al. 2019), highlighting the need for alternative habitat and refugia during temperature extremes. Whereas parts of the southern population may be threatened by rising sea levels impacting low-lying habitat e.g., at Howe Flat (0–5 m asl). Eastern Bristlebird ability to move in response to climate change will be limited by their poor dispersal ability and lack of habitat connectivity (OEH 2012).

 An analysis of the effects of climate change on 101 bird taxa proposed ongoing population monitoring and the identification of climate refugia as key priorities and fire management and weed and feral animal control as key in situ management actions (Garnett et al. 2013).

3.2.5            Lack of genetic diversity

 Genetic diversity is important for the viability of populations and the evolutionary potential of species. Habitat fragmentation and isolation of natural populations can reduce effective population size (Love Stowell et al. 2017), leading to loss of genetic diversity and inbreeding. Populations that are restricted to small, isolated habitat patches can fall into an 'extinction vortex', where low genetic diversity and susceptibility to extreme events (e.g., fires, disease and drought) limit population recovery. In such cases, habitat protection or restoration may not be sufficient for population increase.

 Genetic assessment of the Eastern Bristlebird by Roberts et al. (2011) showed there was insufficient phylogenetic distinctiveness between populations to support classification of the northern population as a subspecies. Both the northern and southern populations were less genetically diverse then the central population, consistent
 with their smaller population sizes (Weeks et al. 2016). Using a limited dataset of six