The Long-nosed Potoroo (SE Mainland) is a medium sized marsupial of the order Diprotodontia. There is considerable variation between sizes in males and females. Males and females have a body length (excluding the tail) between 287–410 mm and 259–378 mm respectively. Tail lengths range between 204–262 mm (males) and 198–254 mm (females) with males (740–1640g) being typically heavier than females (660–1350g). The Long-nosed Potoroo (SE Mainland) can be identified by a brown to grey upper body and paler underbody. They have a long nose that tapers with a small patch of skin extending from the snout to the nose. The length of the feet is shorter than their head length. They are smaller than the Long-footed Potoroo (Potorous longipes).
Long-nosed Potoroo (northern) |
Potorous tridactylus tridactylus
Status: Vulnerable on the EPBC Act list
Government evidence of impact of climate change:
Australian Government, Conservation Advice, Potorous tridactylus tridactylus
Such catastrophic bushfires are increasingly likely to occur due to climate change (CSIRO Bureau of Meteorology 2015).
Projections of higher temperatures and reduced mean rainfall for eastern Australia due to climate change suggest that the frequency; intensity; and scale of bushfires in the region will increase (CSIRO Bureau of Meteorology 2015).
Changing weather patterns Increasing drought; Timing current Decreased rainfall; increased average temperatures; and mean temperatures Confidence observed increased frequency of droughts are increasingly likely to occur and decreasing due to climate change (CSIRO Bureau of Meteorology 2015).
Climate Change and fire Ensure that a high proportion of the northern long nosed potoroo habitat is maintained in a long unburnt condition ( 20 years).
Maintain and protect areas identified as climate change refuges establish corridors to allow movement to modelled suitable habitat under climate change projections.
Identify high risk subpopulations under climate change and catastrophic depletion scenarios and plan for emergency responses to translocate at risk animals where needed.
In addition; the intensity; frequency and scale of catastrophic bushfires will likely increase due to climate change.
Neither estimate includes the potential for future catastrophic fire events; as may be expected under climate change (CSIRO Bureau of Meteorology 2015).
Given that bushfires are predicted to increase in frequency and intensity under climate change scenarios (CSIRO Bureau of Meteorology 2015); it is reasonable to predict that the available habitats offering optimum habitat (20 years unburnt) will continue to decrease in number and that the scale of future fires may cause similar declines.
Climate change intensifies the impacts of decreased rainfall; increased average temperatures and increased frequency of droughts (discussed above in Table 2 and 4).
In Tasmania; Johnson (1995) found that fire triggered a short term increase in fungal fruiting body production (for four months); which increased feeding by Bettongia gaimardi (Tasmanian bettong); a species that has a similar feeding ecology to the long nosed potoroo.
The northern long nosed potoroo are threatened by habitat loss and fragmentation predation by invasive species; particularly European red foxes (Vulpes vulpes) and feral cats (Felis catus) and inappropriate fire regimes and habitat degradation (due to; for example; forestry activities; livestock; feral herbivores; weeds).
The fire intensity and frequency can permanently alter the diversity and abundance of underground fungi (Johnson 1995); which ultimately puts the most important food source for the long nosed potoroo at risk.
Food resources (in particular underground fungi) can substantially decrease post fire (Martin Temple Smith 2012); and this impact is amplified where fire occurs in combination with a history of other environmental disturbance (e.g. logging) (Claridge et al. 1993).
A short term increase in some underground fungi has been observed post fire (Johnson 1995).
However; the abundance of some fungi after fire may be offset by increased predation risk in post fire habitats (Robley et al. 2016) and decreased abundance of other fungi (Martin Temple Smith 2012).
In particular; grassy weeds can Consequence unknown increase fuel load and alter fire regimes (Setterfield et al. 2013 Trend unknown Milberg et al. 1995).
These altered fire regimes can create Extent across parts of conditions that are detrimental to the maintenance of native the range species and favourable to the establishment and spread of weeds (D Antonio et al. 1992).
The removal of canopy cover and undergrowth lowered soil Consequence moderate moisture and increased susceptibility to fire render harvested Trend increasing disturbed areas unsuitable for long nosed potoroo (Martin Extent across parts of Temple Smith 2012).
The key threats causing this decline are habitat loss and fragmentation; predation (by European red fox) and inappropriate fire regimes.
As catastrophic bushfire was not one of the key threatening processes identified by Woinarski et al. (2014) the 2019 2020 bushfires would likely have a cumulative impact; additional to the existing causes of decline.
A total estimated 41 of the modelled distribution was impacted by fire in the 2019 2020 bushfire season resulting in a population decline of 25 over three generations (Legge et al. 2021).
The unprecedented impact of broadscale location number fires each fire season put as much as 41 of the distribution at risk of impact in a single season; where 24 of the population were estimated to be lost in a single year.
A further risk to the species occurs post fire as the dense understory vegetation is typically lost; and refugial habitats are not available to protect the species from predation by European red fox; feral and domestic cats and wild and domestic dogs (Hradsky 2020 McHugh et al. 2020 Miritis et al. 2020).
Percent of the northern long nosed potoroo modelled range of known and likely to occur distribution that was impacted by different fire severities during the 2019 bushfire season (Legge et al. 2021).
Some habitats may already be experiencing an inter fire interval of fewer than 15 years; and this will increase in the future.
Here the number of locations is based on the threatening process of catastrophic bushfire; as the 2019 bushfires demonstrated that one fire season could impact almost one quarter (24 percent but up to 33 percent) of the population at disparate; geographically separate subpopulations.
Additionally; bushfires can exacerbate the impacts of drought on the abundance of small and medium sized marsupials (Hale et al. 2016 Crowther et al. 2018).
Consequence major precipitation Drought conditions can act synergistically with bushfires to Trend increasing reduce the abundance of small and medium sized marsupials Extent across the (Hale et al. 2016 Crowther et al. 2018). entire range The northern long nosed potoroo often occurs near watercourses and drainage lines; which provide shelter during bushfires (Martin Temple Smith 2012).
Prolonged drought is likely to alter forest structures; food webs and key food availability; though how it will impact the northern long nosed potoroo is not well understood.
Prolonged drought is likely to alter habitat; forest structures; food webs and key food availability; though how this will impact the northern long nosed potoroo population size; distribution and viability are not well understood.