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| THE
ECOLOGICAL SIGNIFICANCE OF RED HILL
Summary:
Red
Hill contains one of the largest remaining remnants of its woodland type, anywhere.
It supports one of the highest diversities of woodland plants recorded in South-eastern
Australia, and is habitat for 57 threatened, rare or regionally uncommon plant,
bird, bat, lizard or grasshopper species. It supports large populations of fifteen
of the threatened or uncommon species. It is a prominent wooded back-drop to the
Parliamentary Triangle and contains historic red-flowering plantings, which Walter
Burley Griffith directed to be planted to enhance Red Hill's Landscape value.
Exposures of metamorphic hornfels and tonalite are a
regionally significant examples of their type and an important educational feature. Full
Statement of Significance Red
Hill supports one of the largest remaining remnants of endangered Yellow Box
- Blakley's Red Gum grassy woodland in Australia. This woodland type once
covered over 25,000 square kilometres, in a belt stretching from Melbourne to
South Queensland. Over 90% of this vegetation belt is now cleared (1). The
woodland on Red Hill is a component of the White Box - Yellow Box - Blakely's
Red Gum Grassy Woodlands and Derived Native Grasslands, which was listed nationally
as critically endangered on 17 May 2006 (2). Yellow Box - Red Gum Grassy Woodland
has been listed as endangered in the ACT since 19 May 1997 (3). Yellow-Box
Red Gum woodland has been highly fragmented and generally exists as isolated
patches smaller than 5ha in area (4). "In terms of size, connectivity,
diversity and condition, the ACT remnants are exceptional, especially the presence
of larger patches (over 100 ha) in good condition." (5) There are no
Yellow Box - Red Gum remnants greater than 100ha in Victoria or the Murray catchment
of NSW (6), and there are no remnants of 200ha or greater in southern NSW (7).
Remnants greater than 200ha are extremely rare. There are only four remnants left
in Australia of 1000ha or more and all are in the ACT (8). Red
Hill supports a Yellow Box -Red Gum woodland of about 275ha. It is a vital
component of the second largest Yellow Box -Red Gum woodland remnant in
Australia that covers about 1,200ha from Red Hill to East O'Malley- Symonston-Mugga
Lane and Callum Brae. Although Hindmarsh Drive will be a barrier to some species,
most woodland plant and animal species will be able to disperse across this highway.
The
Yellow Box - Red Gum woodland has been reduced in area by the Residential development
of East O'Malley Because
of its relatively large size and that much of the understorey is in good condition,
Red Hill supports one of the highest native plant diversities recorded in a Yellow-Box
- Red Gum woodland remnant anywhere in Australia. 196
native woodland species have been recorded on Red Hill. The NSW National Parks
and Wildlife Service has a data-base of plant species records from about 800 grassy
ecosystem (grassland + grassy woodland) sites across south-eastern NSW and the
ACT. Fewer than 5% of these sites have a recorded plant diversity of over 100
species (9). It is relevant that remnants of particularly high quality have been
targeted in the surveys. Given
the size and diversity of its endangered woodland it is not surprising that Red
Hill supports important populations of many uncommon, rare or threatened species:
- Over
7,500 plants of the nationally endangered daisy the Button Wrinkelwort
(Rutidosis leptorrhynchoides) occur on Red Hill in five main locations.
This is the 4th largest known population of this daisy (10). Scattered over the
Hill are about 200 plants of Swanson's Silky Pea (Swainsonia sericea)
which is listed as vulnerable in NSW (11) and is even rarer in the ACT (12).
Button
Wriklewort Regionally
rare or uncommon plants are taken to be those species listed as rare in the ACT
by Crawford (1995) and/or which occur in less than 5% (13) of the 269 grassy ecosystem
sites surveyed in the ACT, Upper Murrumbidgee and Upper Lachlan area (13). Red
Hill contains major populations (1000s of plants) of the regionally rare or uncommon
Yellow Burr Daisy (Calotis lappulacea), Nawarra Burr (a native
tomato Solanum cinereum), Silky Bluegrass (Dichanthium sericeum),
Smooth flax-Lily (Dianella longifolia spp longifolia), a rice
flower (Pimelea linifolia), Drooping She-oak (Allocasuarina
verticillata), Bitter Cryptandra (Cryptandra amara) and Tick
Bush (Indigofera adesmiifolia). Red Hill also supports smaller populations
of 30 regionally rare or uncommon plant species. These species are Green Wattle
(Acacia decurrens), Western Silver Wattle (Acacia decora),
Vanilla Lily (Arthropodium milleflorum), Small Vanilla Lily
(Arthropodium minus), Necklace Fern (Asplenium flabellifolium),
a daisy (Brachycome heterodonta). Milkmaids (Burchardia
umbellate), Billy Buttons (Craspedia variabilis), Barbed
Wire Grass (Cymbonpogon refractus), Austral Hound's Tongue (Cynoglossum
australe), Large Tick-trefoil (Desmodium brachypodum, a large
clover like plant with small pink pea flowers arranged on a long spike), Nodding
Chocolate Lily (Dichopogon fimbriatus), Forest Hedgehog Grass
(Echinopogon ovatus), Berry Saltbush (Einadia hastate) Bottlewashes
(Enneapogon nigricans), Native Flax (the herb Linum marginale),
Austral Trefoil (sub-shrub with sweet-pea like flowers Lotus australis),
Native Mint (Mentha diemenica), Yam Daisy (Microseris
lanceolata), Hairy Stinkweed (Opercularia hispida), Lesser
Guinea Flower (Hibbertia calycina), a fireweed (Senecio hispidus),
Many-flowered Knawel (Scleranthus diander), Tiger Orchid
(Diuris sulphurea), Native Sorghum (Sorghum leiocladum),
Rats Tail Grass (Sporobolus creber), Notched Swainson-pea
(Swainsona monticola), Common Fringe Lily (Thysanotus tuberosus),
Small-leafed Clematis (a vine Clematis microphylla) and a matrush
(Lomandra bracteata). ·
The invertebrate fauna of Red Hill is yet to be surveyed, but as a large woodland
patch it is likely that Red Hill would support populations of invertebrate species
of conservation significance. On 22 October 2006 three females of the threatened
flightless Perunga Grasshopper (Perunga ochracea), were observed
near Davidson's Trig. This grasshopper has an X across its back, blue "shoe"
colouring at the extremity of its feet and reduced wings. The Grasshopper was
previously observed in the early 1990s, behind Calthorpe's House, and in 2008
on the slope above the Golf Course Road (18).
Perunga
Grasshopper on Red Hill ·
Red Hill is known habitat to many threatened, declining or regionally uncommon
woodland birds. However Red Hill's woodland bird population is in decline, species
that were abundant 25 years ago are now rare. The decline is probably due to several
factors including: the general decline of woodland birds across south-eastern
Australia; the reduction of a woody weed cover from 20% to under 5%, underscrubbing
of eucalypt and wattle regrowth because of increasing fire protection requirements
and loss of the key breeding habitat for the remnant with the building of housing
adjacent to creek-lining woodland at East O'Malley. Nevertheless there are a few
woodland bird species that maintain a large population of Red Hill, several significant
species continue to breed sporadically on the Hill, while, given its relatively
large size and connectivity, Red Hill may be important to the recovery of woodland
birds in the ACT. ·
Since 1997 regular surveying has indicated that Red Hill maintains a steady population
of 12-14 family groups of the Speckled Warbler (Chthonicola sagittata),
with annual breeding events. This bird is listed as vulnerable to extinction in
NSW14. Monitoring of woodland sites within the ACT (including Red Hill), by the
Canberra Ornithologist group indicates a increase of this bird in woodland remnants
in ACT, however it is still regarded as an uncommon though widespread species.
Speckled
Warbler (photo H Fallow)
The
ACT is a stronghold for the Gang Gang Cockatoo (Callocephalon fimbriatum)
which breeds on Red Hill. Outside of the ACT the Gang Gang has suffered a 44%
reduction in reporting rate over the last 20 years and is listed as vulnerable
to extinction in NSW.14 There are at least 4 nesting trees within the Red Hill
woodland, all which appear to be utilised each year. ·
The ACT is also a regional stronghold of the Scarlet Robin (Petroica
multicolor) and Flame Robin (Petroica phoenicea), both of which
are listed as vulnerable in NSW. From April to June the Scarlet Robin is
a regular visitor to the Hill, while the Flame Robin is an occasional visitor.
Scarlet
Robin (photo H Fallow) Several
birds listed as threatened in the ACT occasionally breed on the hill. These include
the Varied Sittella (Daphoenositta chrysoptera) which bred in 2009
in vegetation on edge of the Golf Club and the White-winged Triller (Lalage
sueurii), Diamond Firetail (Stagonopleura guttata) both of which
are last recorded as breeding at East O'malley in the spring before this area
was developed. Both have in earlier times bred elsewhere on the Hill. A pair of
Little Eagles (Hieraaetus morphnoide) regularly bred in a nest tree
at East O'Malley and foraged over Red Hill, most days. Since the development of
East O'malley, only a lone individual bird is occasionally sighted on Red Hill.
The Glossy Black Cockatoo (Calyptorhynchus lathami), a small black
cockatoo with red tail feathers, is listed in vulnerable in NSW and has been recommended
for vunerable listing in the ACT. This cockatoo is an occasional visitor that
feeds on the Hill's Casuarina cones. There
are a further five woodland birds that are considered by the Canberra Ornithologists
Group as rare or uncommon in the ACT region and which occasionally breed on Red
Hill. These species are Painted Button Quail (Turnix varia - young
birds observed in 2006 and 2007 near lookout summit), Double-barred Finch
(Taeniopygia bichenovii -nest observed in 2008), Dollar Bird (Eurystomus
orientalis - dependent young observed 2007), White-browed Woodswallow
(Artamus personatus - courtship display observed 2009) and Southern
Whiteface (Aphelocephala lucopsis - nest building observed in 2009). ·
Most of Red Hill is composed of metamorphic rock, but Silurian volcanic rocks
outcrop behind Garran in the south-west of the Nature Park. The nationally vulnerable
and aptly named Pink-tailed Worm Lizard (Aprasia parapulchella)
has twice been recorded under Red Hill's volcanic rocks. This legless lizard feeds
on ants and moves through their burrows. It is rarely seen and even in known habitat
many hundreds of rocks have to be overturned to locate it. Red Hill is likely
to support a viable but small population of this lizard (17).
The
red soil of Red Hill is caused by weathering of rocks called hornfels.
Hornfels are created when sedimentary rock is metamorphosed, without melting,
by contact with very hot, molten rock. Red Hill contains some of the best exposures
of hornfels in the region and is an important geological education site
(19). The best examples of hornfels on Red Hill are the hard rock outcrops
between the summit restaurant and the golf course access road, in the old quarry
50m south-west of the restaurant and rock outcrops above Strickland Street, Deakin.
A boulder of Tonalite, volcanic rock formed deep under the ground, is exposed
above the Golf Club Road and is a regionally important example of its type. Hornfels
is a hard rock and very weathering resistant. This explains why Red Hill remains
as a fairly flat and long ridge rising above surrounding plains. In designing
Canberra, Walter Burley Griffith saw Red Hill as an important landscape element,
with the prominent ridge-line forming the backdrop to the Parliamentary Triangle. Ninety
year old plantings on Red Hill are another important association with Walter Burley
Griffith and also with the ACT's first Government Nursery Chief, Charles Weston.
By the turn of the nineteenth century much of the higher vegetation on Red Hill
had been cleared. Burley Griffith called for replanting and the cessation of grazing.
Grazing continued until 1997, but plantings occurred from 1917 until the early
1920s. Burley Griffith's replanting schemes for Canberra's hills had different
coloured shrubs on each of the hills, Mt Ainslie was to be pink, Mt Pleasant white
and of course Red Hill was to be planted with red flowering plants. About 5,000
plants of Callistemon citrinus (Crimson Bottlebrush) and Grevillea
rosmarinifolia (Rosemary Grevillea) were planted under Weston's direction.
The Bottlebrush were planted in rows just to the east of the kiosk. The original
plantings can still be observed as bottlebrush is able to resprout following fire.
The Grevillea was planted adjacent to the summit road, just above the Golf Course
road junction. Grevilleas are killed by fire, but the plantings have set seed
so that these red flowering plants also remain on Red Hill. Footnotes
1.
Listing advice for White Box - Yellow Box - Blakely's Red Gum Grassy Woodlands
and Derived Native Grasslands - 2006, Department of the Environment, Water, Heritage
and the Arts p9
2. ACT
Department of Environment
3. ACT
Department of Environment
4. Gibbons P. and Boak M. (2000) The
Importance of Paddock Trees for Conservation in Agricultural Landscapes. A
discussion paper for consideration by the Riverina Highlands Regional Vegetation
Committee. (NSW National Parks and Wildlife Service).
5. listing advice
for White Box - Yellow Box - Blakely's Red Gum Grassy Woodlands and Derived Native
Grasslands - 2006, Department of the Environment, Water, Heritage and the Arts,
p.5
6. Davidon I. Woodland Management Notes for the Murray Catchment. NSW
Department of Environment and Conservation, 2005 and the nomination document of
Yellow Box Red Gum woodland for listing as an endangered ecological community.
7.
Rainer Rehwinkel, NSW Department of Environment and Conservation, Grassy Ecosystems
research Officer, Personal Communication, 2006.
8. ACT Government 2004
Woodlands for Wildlife: ACT Lowland Woodland Conservation Strategy. Action Plan
No. 27. (Environment ACT, Canberra), Chapter 5.
9. Rainer Rehwinkel, NSW
Department of Environment and Conservation, Grassy Ecosystems research Officer,
Personal Communication, 2006.
10. 10. Population number from 2007 count
of this endangered daisy on Red Hill. Counts of other populations are available
in the Recovery Plan for the species prepared by the NSW Department of Environment
and Climate Change.
11. NSW
Department of Environment
12.Crawford I. (1995). Rare or Threatened
Vascular Plants in the ACT Region. Unpublished report for Parks, Conservation
and Lands.
13.Ibid
and see note 7
14. NSW
Department of Environment
15. ibid
16. ibid
17. Reid
J.R.W. (1999) Threatened and Declining Birds of the NSW Sheep-Wheat Belt. A report
to the NSW National Parks and Wildlife Service.
18. Osborne W. and Jones
S. (1995) Recovery Plan for the Pink-tailed Worm Lizard (Aprasia parapulchella).
ACT Parks and Conservation Service Technical Report 10. Note: This lizard was
also sighted during an activity of Red Hill Regenerators in 1999.
19. The
Grasshoppers were observed during weeding activities of Red Hill Regenerators,
photographs were taken during the 2006 observation and the identity of the grasshopper
confirmed by Environment ACT.
20. Owen M. 1987. Geological monuments in
the Australian Capital Territory. Australian Heritage Commission.
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