The Kangaroo Island Southern Emu-wren is one of Australia’s smallest birds, yet is the largest of the Emu-wrens, with a wingspan of 9 to 19 cm and a weight of 5 to 9 g. Body length is around 6 cm and the tail length around 10 cm, with a total length of around 16 cm. Adult birds are olive grey to olive brown streaked black above, while underparts are tawny brown. Male birds have a distinctive blue chin and throat, which is absent in females. The Emu-wren’s tails are filamentous and comprised of six emu-like feathers. Plumage varies with habitat and in cooler, wetter areas, individuals are darker, with thicker streaks. Eggs are oval shaped and white or cream coloured, moderately speckled with fine reddish-brown spots and flecks.
Kangaroo Island Southern Emu-wren |
Stipiturus malachurus halmaturinus
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
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Australian Government, Conservation Advice, Stipiturus malachurus halmaturinus
Climate change Increased likelihood of Status historical; current Average temperatures in Australia have extreme events (i.e.; future increased by around 1.4 C in the past heatwave; and drought) Confidence known century (BOM CSIRO 2020 IPCC 2021); and global temperatures are likely to exceed Consequence severe 1.5 C in the next 20 years if global Trend increasing greenhouse gas emissions are not reduced Extent across the entire range immediately (IPCC 2021).
The cumulative effect of the climate anomalies has led to; and will continue to; increase the likelihood of extreme events such as droughts and heatwaves (BOM CSIRO 2020).
This change in climate may have detrimental impact on the subspecies and their habitat.
Climate anomalies will also increase the risk of wildfire (see Increase in frequent; large extent; high intensity wildfires).
An analysis by a team from the National Environmental Science Program (NESP) Threatened Species Recovery Hub showed that a large proportion of the range of Kangaroo Island Southern Emu wren was affected by these fires 57 was burnt in high to very high severity fire; and a further 11 was burnt in low to moderate severity fire (Legge et al. 2021).
A structured expert elicitation process was used to estimate the proportional population change for this species from pre fire levels to immediately after the fire and then out to 10 years after the fire; when exposed to fires of varying severity.
For comparison; experts also estimated the population change over time in the absence of fire by 10 years; the overall population of Kangaroo Island Southern Emu wren after the fire was estimated to be 5 lower than it would have been; had the 2019 2020 fire not occurred (Legge et al. 2021).
The known range of the subspecies occurs in a fire prone area; that has been heavily impacted by wildfires in the past.
While fire is integral to the ecology of Kangaroo Island; the 2019 2020 bushfires were the most extreme in recorded history and were unprecedented in their scale; speed and intensity (Government of South Australia 2020b).
Extreme fire weather (Di Virgilio et al. 2019 Dowdy et al. 2019) driven by longer and more severe droughts (Evans et al. 2017) and more frequent heatwaves (Herold et al. 2018) is likely to increase in frequency and intensity in coming decades and poses the greatest risk to the subspecies (Paton et al. 2021).
The flammable nature of some weeds; including non endemic species such as Tasmanian Blue Gum (Eucalyptus globulus); may also increase fire risk and severity (Government of South Australia 2021).
Table 1 Threats impacting Kangaroo Island Southern Emu wren Threat Status and severity a Evidence Fire Increase in frequent; large Status historical; current While fire is vital to the ecology of Kangaroo extent; high severity future Island; the 2019 2020 bushfires were the wildfires Confidence known most extreme in recorded history; burning approximately half of the island (DEW 2020 Consequence severe Todd Maurer 2020).
The fire was also Trend increasing unprecedented in its scale; speed and Extent across the entire range intensity (Government of South Australia 2020a).
For example Ensure fire suppression strategies also consider impacts on the population or its habitat.
The number of locations was determined using the 2019 2020 fire extent on Kangaroo Island; which heavily impacted the western side of Kangaroo Island; though unburnt habitat fragments remained within the fire affected area.
For comparison; experts also estimated the population change over time in the absence of fire by 10 years; the overall population of Kangaroo Island Southern Emu wren after the fire was estimated to be 25 lower than it would have been; had the 2019 fire not occurred (Legge et al. 2021).
Mortality from the 2019 2020 bushfires has ceased; however the frequency and extent of intense wildfire is predicted to increase.
Extreme fire weather (Di Virgilio et al. 2019 Dowdy et al. 2019) driven by longer and more severe droughts (Evans et al. 2017) and more frequent heatwaves (Herold et al. 2018) is likely to increase in frequency and intensity in coming decades and poses the greatest risk to the subspecies (Paton et al. 2021).