Download Ensuring the long-term survival of the Endangered Western ringtail

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Ensuringthelong-termsurvivaloftheEndangered
Westernringtailpossum(Pseudocheirusoccidentalis)in
theShireofAugusta-MargaretRiver:Theimpactofrecent
firesandthethreatoffuturefires
Background
The Shire of Augusta-Margaret River established a Biodiversity Working
Party within its Sustainability Advisory Committee (SAC) in 2008 and accepted its
first recommendations that:
1. The Shire initiate an upgrade survey of peppermint woodlands likely to
provide suitable habitat for Western Ringtail possums
2. The Shire seek external funding to engage a biological consultant to
survey remnant Western Ringtail populations. The survey should also
enlist the help of ratepayers through the distribution of a questionnaire
to collect evidence of sightings, road-kills, dreys (nests) and scats
(droppings).
3. The Shire initiate a signage policy designed to increase the public’s
awareness of an endangered marsupial species in its midst1.
Although two applications have been made to the State Government for
funding via its Community Grants Scheme, neither was successful. In 2015 $10k
remaining in the Environment Management Fund were reallocated for a public
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Shire of Augusta–Margaret River Biodiversity Conservation Strategy, Discussion paper Prepared by the
Shire of Augusta-Margaret River, 23 May 2005
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awareness programme involving signage, brochures and other means of alerting
ratepayers to the plight of ringtail possums.
Biology of Western Ringtail Possums
The Western ringtail possum, (Pseudocheirus occidentalus) is now listed as
“Endangered” under the Federal EPBC Act, a change from its former listing as
“Vulnerable” in the 2000 IUCN Red List of Threatened Species and “Threatened”
under the Western Australian Wildlife Conservation Act2. It is my understanding
that a proposal is before the Federal Minister for it to be listed as “Critically
Endangered” (CE), the highest level of vulnerability under the EPBC Act.
his possum is found almost exclusively associated with peppermint trees
(Agonis flexuosa) in the Shire, which provide both food and habitat for this
species.
Nineteenth
century
surface cave deposits show
that
the
Western
ringtail
possum was widely distributed
throughout the south-western
forests
of
Western
Australia
from 120 kilometres south-east
of Geraldton to the southern edge of the Nullarbor Plain, with inland records as
far as Tutanning Nature Reserve. It was first reported to be in decline in 1909. The
2
Burbidge, A. (1997-98). Endangered: Western Ringtail Possum. LANDSCOPE 13(2): 49.
de Tores, P., Rosier, S. and Paine, G. (1998). Conserving the Western Ringtail Possum.
LANDSCOPE 13(4): 28.
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pattern of decline has been local and patchy. Local extinctions have been most
extensive in inland areas, occurring as recently as 1950-1970. Most populations
are now restricted to near coastal areas of peppermint woodland and
peppermint/tuart
associations
from
the
Australind/Eaton
area
to
the
Waychinicup National Park. It is relatively common and abundant in a small part
of the lower Collie River valley and the Perup Nature Reserve and surrounding
forest blocks near Manjimup – viable groups also live in some parts of urban
Busselton and the Federal Department of the Environment, Water, Heritage and
the Arts (DEWHA) have recently declared a coastal strip between Bunbury and
Busselton as core habitat for the species3.
Key To Map: Black = present distribution;
Mid-grey = historic (> 30 years); Pale-grey =
Fossil
The western ringtail possum is thought to have become locally extinct at all
former inland locations except at Perup and surrounding forest blocks - the only
location where the ringtail is now found in the absence of peppermint4.
3 Significant impact guidelines for the vulnerable ringtail possum (Pseudoicheirus occidentalis) in the
southern Swan Coastal Plain, Western Australia. EPBC Act Policy Statement 3.10, (2009).
4
Wayne, A. F., Rooney, J. F., Ward, C. G., Vellios, C. V. and Lindenmayer, D. B. (2005) The life history
of Pseudocheirus occidentalis (Pseudocheiridae) in the jarrah forest of south-western Australia.
Aust. J. Zool., 53: 325-337.
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Little is known of the distribution and status of the ringtails in the Shire.
There is a remnant population of ringtails in East Augusta but, paradoxically, no
signs of their presence in the main townsite of Augusta until very recently with the
first confirmed sightings in the last 3 months.
Threats to Ringtails
The major factors thought to be contributing to the decline of the ringtail
include habitat loss and/or modification, predation by introduced predators,
and changing fire regimes.
In most coastal populations the fox is the main predator of the western
ringtail possum as shown by monitoring of re-introduced populations. Clearing of
coastal Peppermint in the Bunbury-Augusta and Albany areas is contributing to
habitat fragmentation while prescribed burning of these areas needs to be
managed
to
maximize
population
survival
and
enhancement.
Housing
developments, such as that in East Augusta, have led to substantial clearing of
peppermints, forcing the possums to come to the ground at night where they
are vulnerable to predation by cats and dogs. At last count, East Augusta has 48
resident dogs, one of which is reported by its owner to bring in “a possum every
couple of weeks”.
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Road-kills are also a significant source of mortality in townsites and built-up
areas. A recent two-year study in suburban Sydney recorded 600 road-kills,
averaging 5.45 possums per week in a 36 km stretch of roadway5. A similar study
analysing the age of possums killed on roads showed that they are mainly
younger animals with dispersing sub-adult males predominating6. Similar studies
have not been carried out in WA but a recent survey of Western ringtails in the
townsite of Dunsborough revealed high densities of possums with 118 individuals
located over 6 nights close to busy roads7.
The Impact of 2011/2 Fires
The recent devastating fire in Margaret River/Prevelly resulted in the death
and injury to substantial numbers of Ringtail possums according to reports from
carers in Dunsborough and Busselton. The second fire that threatened East
Augusta, and led to the evacuation of all residents, fortunately did not reach the
townsite. East Augusta is home to a large localised population of ringtails that
has been monitored by the Environmental Research Group Augusta (ERGA) for
the past two decades. Local residents are fearful of another fire in the future and
DFES has commenced planning to ‘fire-proof’ the townsite. Unless made aware
of the ringtail population, this could result in extensive clearing of peppermint
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Russell, T. C., Herbert, C. A. and Kohen, J. L. 2009 High possum mortality on urban roads:
implications for the population viability of the common brushtail and the common ringtail possum.
Aust. J. Zool., 57: 391-397.
6 Giffney, R. A., Russell, T. C. and Kohen, J. L. 2009 Age of road-killed common brushtail (Trichosurus
vulpecula) and common ringtail possums (Pseudocheirus peregrinus) in an urban environment.
Aust. Mammal., 31: 137-142.
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Thompson, S. A. and Thompson, G. G. 2009 A case for in situ management of Western ringtail
possums, Pseudocheirus occidentalis, in developed areas. J. Roy. Soc. WA. 92: 269-276.
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trees with the loss of essential habitat for ringtails. ERGA has been in contact with
the FCO for East Augusta, raising the problem of the long-term protection of
ringtail
possum
habitat,
but
discussions
need
to
proceed
with
DFES
representatives, who are probably unaware of the situation in the Shire.
Recommendation
That the SAC requests Council consider:
1. Requesting feedback from DFES on any prescribed burning that is
planned or has taken place in habitat within the Shire that is likely to
be occupied by Western ringtail possums.
2. Expanding a signage and information policy designed to increase the
public’s awareness of an Endangered marsupial species in its midst.
Don Bradshaw
December 2016