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Brush Tailed Rock Wallaby Sanctuary Investigation (1)

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Brush Tailed Rock Wallaby Sanctuary Investigation
The Brush-tailed Rock-wallaby is a very special species to Kangaroo Valley, yet is
sadly endangered. Before the fires it was estimated that only 20 adults were in the
region, and since then much of their habitat has been destroyed. Thus, it is
extremely important to determine if there is a suitable habitat that could become a
sanctuary for these beautiful animals and help their population grow!
Brush-tailed Rock Wallaby Fact Sheet
Scientific name: ​Petrogale penicillata
Conservation status in NSW: E
​ ndangered
Description
The Brush-tailed Rock-wallaby has a characteristic, long and bushy, dark
rufous-brown tail that is bushier towards its tip. It has long, thick, brown body-fur
that tends to be rufous on the rump and grey on the shoulders. The fur on its chest
and belly are paler. It also has a characteristic white cheek-stripe and a black stripe
from its forehead to the back of its head. It is relatively small and muscular, which
enables it to be fast and agile in its rocky habitat. The average weight of this species
is about 8 kg for males and 6 kg for females.
Distribution
Current vs. former distribution of the Brush Tailed Rock Wallaby
Estimated distribution in the Shoalhaven in 2000. Current distribution would be much
less.
It is estimated that there are only 20 Brush Tailed Rock Wallabies in the Shoalhaven
Region, most of which are in Kangaroo Valley.
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Habitat and ecology
● Occupy rocky escarpments, outcrops and cliffs with a preference for complex
structures with fissures, caves and ledges, often facing north because they
can find a sunny ledge in winter and cool caves in summer.
● Feeds on a variety of plants including native grasses, orchids, figs, bark, fruits,
flowers, foliage of shrubs and trees and ferns.
● Most foraging occurs at night, in grassy habitats close to their daytime
refuge.
● Shelter or bask during the day in rock crevices, caves and overhangs and are
most active at night.
● Highly territorial and are highly territorial with an average home range size of
about 15 ha (1 ha is about the size of a rugby field).
● Live in family groups of 2 to 5 adults and usually one or two juvenile and
subadult individuals.
● Dominant males associate and breed with up to four females.
Threats
Foxes are believed to be the most common reason for the brush-tailed
rock-wallaby's decline. Foxes were introduced to Australia in the 1870s and have
contributed to the decline of a range of native species. Foxes are agile climbers and
are well-sized to fit into the crevices where young wallabies shelter while their
mothers feed.
However, rock-wallabies face a number of other threats. These include:
● being preyed on by dogs and cats
● competition with goats and rabbits for habitat and food
● habitat degradation by human disturbance, clearing, weed invasion taking
over land from native flora for them to eat, fire and drought
● diseases such as toxoplasmosis, which is spread by cats
● inbreeding.
Adaptations and Behaviour
The BTRW are able to leap up and down near-vertical rocks and trees because they
have special gripping finger prints on their back feet as well as a long tail for
balance and steering. They are most active at dusk and dawn, hiding from
predators behind plants and in crevices, straying further from safe refuge areas in
the dark to feed.
The presence of their distinctive scats around highly rocky habitat is often the best
sign of their presence. Brush-tailed rock-wallaby scats can be found throughout
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their rocky habitat, particularly on ledges and boulder piles where they sit to sun
themselves.
Their scats can be recognised from other animals' scats by their proximity to rocky
habitat and their distinctive size and shape. They are usually a cylindrical shape
with a pinch at one end.
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Site 1 habitat assessment - record sheet
​Location _______________________
Abiotic elements
Temperature
Aspect
Air temp
Leaf litter
depth
Altitude
Moisture
Rock height
and features
pH
Nitrogen
Phosphorus
Potassium
Biotic elements
Use the plant identification sheets to identify species. Fill out the table to determine how
the flora fits in with the Brush Tailed Rock Wallaby habitat.
Species
Abundance *
Part of
diet? Y/N
Weed?
Y/N
*Abundance - give a score according to the following:
1 = low abundance (1 - 4)
2 = more abundant (5 - 20)
4
3 = very abundant (20+)
Fauna
Record evidence of animals in the landscape; animals observed, scats, burrows, sounds…
Species
Evidence observed
Notes on data: The following table outlines the usual healthy parameters for abiotic
components in Kangaroo Valley. The fires may have led to unhealthy levels which can cause
a decline in native flora and an influx of weeds.
Soil temperature
Unhealthy (low)
Healthy
Unhealthy (high)
Leaf litter depth
<1cm = unhealthy
2 - 3cm = adequate
3cm +
Soil pH
<4
4 - 5.5
>5.5
Nitrogen
<15ppm
15 - 30ppm
>30ppm
Phosphorus
<30ppm
30 - 50ppm
>50ppm
Potassium
<130ppm
130 - 190ppm
>190ppm
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Site 1 habitat assessment - analysis
Based on the information above, discuss the suitability of the site for a Brush Tailed Rock
Wallaby Sanctuary. Include both the positive and negative features of the site, and how these
would benefit/ hinder the Brush Tailed Rock Wallaby.
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Site 2 habitat assessment - record sheet
​Location _______________________
Abiotic elements
Temperature
Aspect
Leaf litter
depth
Altitude
Moisture
Rock height
And features
pH
Nitrogen
Phosphorus
Potassium
Biotic elements
Use the plant identification sheets to identify species. Fill out the table to determine how
the flora fits in with the Brush Tailed Rock Wallaby habitat.
Species
Abundance *
Part of
diet? Y/N
Weed?
Y/N
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*Abundance - give a score according to the following:
1 = low abundance (1 - 4)
2 = more abundant (5 - 20)
3 = very abundant (20+)
Fauna
Record evidence of animals in the landscape; animals observed, scats, burrows, sounds…
Species
Evidence observed
Notes on data: The following table outlines the usual healthy parameters for abiotic
components in Kangaroo Valley. The fires may have led to unhealthy levels which can cause
a decline in native flora and an influx of weeds.
Soil temperature
Unhealthy (low)
Healthy
Unhealthy (high)
Leaf litter depth
<1cm = unhealthy
2 - 3cm = adequate
3cm +
Soil pH
<4
4 - 5.5
>5.5
Nitrogen
<15ppm
15 - 30ppm
>30ppm
Phosphorus
<30ppm
30 - 50ppm
>50ppm
Potassium
<130ppm
130 - 190ppm
>190ppm
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Site 2 habitat assessment - analysis
Based on the information above, discuss the suitability of the site for a Brush Tailed Rock
Wallaby Sanctuary. Include both the positive and negative features of the site, and how these
would benefit/ hinder the Brush Tailed Rock Wallaby.
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INTERPRETING THE HABITAT ASSESSMENT
TREES ​- provide nesting sites and food for nectar and fruit eaters.
HEALTHY TREE CANOPY ​– a healthy canopy will indicate the site is relatively free of human
disturbances (eg; erosion, compaction) or natural disturbances (storm damage, major presence of
mistletoe)
SHRUBS ​– dense native shrubs allow small native animals and birds to shelter and to hide from
predators such as feral cats.
HERBS & GROUND COVERS ​– provide the food for finches, lyrebirds, lizards, frogs and wallabies,
and also provide habitats for small mammals, insects and spiders.
NATIVE PLANTS ​– native plants are adapted to the Australian environment. They require less
watering, little or no fertiliser and provide the right food at the right time for the native animals that
have evolved with them.
HOLLOWS ​– are important homes for native wildlife. It can take over a hundred years for hollows to
develop in forests. Hollows also provide nesting sites for birds, possums and bats.
ROCKS & CREVICES ​– provide habitat for many animals to live and feed and for certain species of
plants to grow – they are valuable habitat. Bush rock collection has had a significant impact on our
wildlife and degraded many areas.
LEAF LITTER ​– provides habitat for smaller animals like lizards, geckos, frogs and invertebrates.
Leaf litter, when broken down, provides humus – a rich source of nutrients for trees and shrubs.
LOOSE BARK ​– provides habitat for invertebrates, spiders and lizards.
LOGS OR FALLEN BRANCHES ​– 20% of native mammals need logs to nest in. They provide
habitat for invertebrates and reptiles. When they decay they provide nutrients for the ecosystem.
POND / WATER ​– provides homes for frogs, native fish, dragonfly nymphs and other invertebrates.
Also drinking water for birds and animals.
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PLANTS WITH FRUIT / SEEDS ​– an important source of food for birds, bats, possums and
invertebrates.
PLANTS OF DIFFERENT AGES ​– indicates that an area has more habitat spaces for a variety of
plants and animals.
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