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Appendix D - Habitat Descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Rapid Creek (northernheadwater)
Vegetation: Rap-01-T,Nov 2017.
Melaleuca Communities: Regeneration Melaleuca
viridiflora low woodland to low open woodland with
Pandanus spiralis and Lophostemon lactifluus.
Commonly includes areas of seasonal swamp.
Dominant flora:
• Carallia brachiata (Carallia)• Corymbia bella (Ghost Gum)• Erythrophleum chlorostachys (Ironwood)• Eucalyptus tetrodonta (Darwin Stringybark)• Melaleuca viridiflora (Broad-leaved Paperbark)• Pandanus spiralis (Pandanus)
This ephemeral channel was dry when visited. It is unlikely to provide much
aquatic habitat, besides some small pools (<1 m wide by a few meters long)
during the Wet Season. Such habitat may provide breeding opportunities for
aquatic macroinvertebrates, but their success of development would depend
on seasonal rainfall. Dry Season refuge would be available further
downstream where a large weir helps saturate a broad Pandanus swamp.
Riparian and terrestrial habitat is expansive across this area of the base. The
woodland has no public access and relatively minor disturbance. Fauna
surveys in 2012 found one amphibian, 36 birds, six mammals and eight
reptile species residing in this restricted area (ELA, 2012).
This habitat is part of a contiguous bushland area spanning the full length of
Rapid Creek, with small breaks at road corridors. Fauna are relatively free to
move within this corridor.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Rapid Creek (southernheadwater)
Sampling sites:Fish: RC4 upstream of‘Woodland Walk’ inPandanus swamp, March2017.Vegetation: Rap-02-Tright side of channel onfloodplain, Nov 2017.Terrestrial invertebrates:Rap-02-T right side ofchannel on floodplain,Dec 2017.Terrestrial vertebrates:Rap-02-T left side ofchannel above floodplainin the ‘Woodland Walk’area, approximately800 m downstream of theinvertebrate site, April2018.
Melaleuca Communities: Regeneration Melaleuca
viridiflora low woodland to low open woodland with
Pandanus spiralis and Lophostemon lactifluus.
Commonly includes areas of seasonal swamp.
Monsoon Rainforest: Mixed species monsoon
rainforest associated with permanent moisture. Closed
canopy 20-25 m tall dominated by evergreen species,
including Acacia auriculiformis, Calophyllum soulattri,
Carpentaria acuminata, Horsfieldia australiana and
Syzygium nervosum.
Lophostemon Communities: Lophostemon lactifluus,
Pandanus spiralis open forest, with Sorghum intrans
and Pennisetum polystachion grassland understorey,
and mixed shrubs and herbs.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Acacia holosericea (Silver Wattle)• Alphitonia excelsa (Soap Tree)• Breynia cernua (Breynia)• Buchanania obovate (Green Plum)• Carallia brachiata (Carallia)• Corymbia bella (Ghost Gum)• Erythrophleum chlorostachys (Ironwood)• Eucalyptus tetrodonta (Darwin Stringybark)• Livistona humilis (Sand Palm)• Pandanus spiralis (Pandanus)• Philydrum lanuginosum (Frogsmouth)• Planchonia careya (Cocky Apple)• Syzygium suborbiculare (Red Bush Apple)
Similar to Rap-01 within the same protected woodland and within the fauna
survey area conducted by ELA in 2012. This ephemeral channel is about 2 m
wide and <0.5 m deep during Wet Season base flows. The channel has been
artificially dredged and straighten to direct flows away from the airfield.
Aquatic habitat here is connected to the downstream swamp, with greater
water-holding capacity and presence of aquatic vegetation than Rap-01.
The riparian zone on the right bank is a dense line of trees fringing the
channel, to a grassy floodplain that transitions to an expansive Eucalypt
woodland. The left bank is also lined with trees, but has a narrow buffer
between the clear airfield.
The terrestrial vertebrate sampling was moved further downstream into the
DIA ‘Woodland Walk’. This area was heavily impacted by Cyclone Marcus
(Category 1 cyclone that struck two days before the fauna trapping
commenced). The storm had stripped leaves off the canopy and knocked
over many trees, which in turn crushed small trees and shrubs. Despite the
disturbance, habitat was still abundant with Eucalypt and Pandanus forests.
The area lacked large trees with hollows, which is typical in Darwin following
destruction of many trees in Cyclone Tracy (1974).
Groundwater discharge was apparent in the ‘Woodland Walk’ closer to the
creek. Low elevation areas had moist black soil. Higher elevation areas had
red soils, often shallow over coffee rock and/or dumped rock from historic
land use.
This habitat is part of a contiguous bushland area spanning the full length of
Rapid Creek, with small breaks at road corridors. Fauna are relatively free to
move within this corridor.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Rapid Creek (upper)
Around spillway nearresort.
Sampling sites:
Fish: RC3 from abovespillway to 250 mdownstream, March2017.
Fish & vegetation: Rap-03-F from above spillwayto 50 m downstream,Nov 2017.
Terrestrial invertebrates:Rap-03-T right side ofchannel on floodplain,Dec 2017.
Terrestrial vertebrates:Rap-03-T right side ofchannel abovefloodplain, April 2018.
Pandanus Communities: Pandanus spiralis low
woodland to very low open woodland, with
Lophostemon lactifluus and Grevillea pteridifolia.
Ground layer dominated by mixed species grasses and
sedges.
Grassland: Sorghum intrans grassland, with Yakirra
nulla, Mnesithea rottboellioides and Aristida holathera.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Andropogon gayanus (Gamba Grass)*• Barringtonia acutangula (Freshwater
Mangrove)• Carallia brachiata (Carallia)• Eucalyptus tetrodonta (Darwin Stringybark)• Heteropogon sp. (Black Speargrass)• Melaleuca viridiflora (Broad-leaved Paperbark)• Persicaria sp. (Knotweed)
This reach has permanent water, but flows cease over the spillway and
between pools during the Dry Season. Above the spillway is a broad
Pandanus swamp with a wetted channel about 4 m wide and 0.5 m deep.
Below the spillway the channel runs across rock rubble into a large shallow
pool (6 m wide and 1 m deep). From here the channel constricts to about 2-3
m wide and <1 m deep. The channel is deeply incised from the fast
catchment flows. Except for one large waterhole that has been historically
dredged (Yankee Pool), the reach downstream is a long narrow run. Fish
habitat is abundant with undercut banks, exposed tree roots, woody debris,
leaf litter and overhanging vegetation. Benthic substrate is mostly compacted
clay and large aggregate. Fine sediments would be flushed downstream.
The riparian corridor is about 120 m wide. The left side is modified by the
airport resort, footpath and drainage channels. Revegetation programs have
been successful in establishing a variety of native trees and controlling
noxious weeds. The right side is a broad Pandanus floodplain on black soil.
The invasive Gamba Grass and other weeds dominate the groundcover.
Beyond the riparian corridor is a strip of woodland trees with a dominant
grassy understorey leading upslope to the Marrara sports complex. The
terrestrial vertebrate sampling occurred here. Habitat availability was suited
to small reptiles, amphibians and mammals. Woodland birds use the corridor,
whilst wetland birds forage closer to the creek. Like site Rap-02 (‘Woodland
Walk’), this area lacked large trees and had been impacted by a recent
cyclone.
This habitat is part of a contiguous bushland area spanning the full length of
Rapid Creek, with small breaks at road corridors. Fauna are relatively free to
move within this corridor.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Rapid Creek (middle)
From Henry WrigleyDrive to weir 400 mdownstream ofMcMillians Road.
Sampling sites:
Fish: RC1 near gaugingweir, March 2017.
Fish: RC2 downstreamHenry Wrigley Dr, March2017.
Fish & Vegetation: Rap-04-F downstream HenryWrigley Drive, Nov 2017.
Terrestrial invertebrates:Rap-04-T left side ofchannel downstreamHenry Wrigley Drive, Dec2017.
Terrestrial vertebrates -Rap-04-T both sides ofchannel downstreamHenry Wrigley Drive,April 2018.
Monsoon Rainforest: Mixed species monsoon
rainforest associated with permanent moisture. Closed
canopy 20-25 m tall dominated by evergreen species,
including Acacia auriculiformis, Calophyllum soulattri,
Carpentaria acuminata, Horsfieldia australiana and
Syzygium nervosum.
Lophostemon Communities: Lophostemon lactifluus,
Pandanus spiralis open forest, with Sorghu intrans and
Pennisetum polystachion grassland understorey, and
mixed shrubs and herbs.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Barringtonia acutangula (Freshwater
Mangrove)• Carallia brachiata (Carallia)• Eucalyptus tetrodonta (Darwin Stringybark)• Maranthes corymbosa (Maranthes)• Pandanus spiralis (Pandanus)• Syzygium angophoroides (Syzygium)• Terminalia microcarpa (Terminalia)
This section of perennial freshwater stream lies about midway in the
catchment. The average channel width was 3 m; depth up to 1.5 m; and
velocity up to 1 m/s. Turbidity was low, but would vary with season and
rainfall events. This reach provides some small refuge pools during dry
season when flow ceases. Substrate was gravel/sand in high flow areas, with
silt and detritus accumulated in backwater areas, especially near the road
culvert. There was good riparian shading and overhanging canopy. Aquatic
macrophytes were absent. Banks were undercut with exposed roots. Large
woody debris were common.
This reach is similar in character between Henry Wrigley Drive and McMillians
Road (1 km). From McMillians Road to the concrete gauging weir (400 m)
the channel changes as it crosses a bedrock riffle into a weir pool (channel
width 4-6 m, depth 0.2-1.5 m).
The riparian zone features multi-strata native vegetation, ranging from dense
canopy with thick leaf litter, to woodland with grassy understorey. Few weeds
occurred, except along road verges. A range of tree size classes are evident.
Flood debris was common across the floodplain.
The terrestrial invertebrate sampling took place in a patch of monsoon jungle
on the left bank, characterised by a closed canopy, vines and dense leaf litter.
The terrestrial vertebrate sampling targeted a range of habitats, but mostly
took place in the woodland adjacent to the right bank. Like site Rap-02
(‘Woodland Walk’), this area lacked large trees and had been impacted by a
recent cyclone, but still provided a mix of habitat types suited to small
animals.
This habitat is part of a contiguous bushland area spanning the full length of
Rapid Creek, with small breaks at road corridors. Fauna are relatively free to
move within this corridor.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Rapid Creek (lower)
From red footbridgealigned with CarringtonRoad to below Power &Water pipe crossing 600m downstream of TrowerRoad.
Sampling sites:
Fish & Vegetation: Rap-05-E around Power &Water pipe in mangrovesdownstream of TrowerRoad, Nov 2017.
Terrestrial invertebrates:Rap-05-T betweenCarrington Road andAldridge Place next tomangroves, Dec 2017.
Brackish reach (Carrington Rd to Aldridge Rd, 200 m)
Monsoon Rainforest: A modified coastal rainforest
community allied to community. Naturalised exotic
trees are present, with some enrichment planting of
local native species.
Melaleuca Communities: Melaleuca cajuputi closed
forest swamp.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Barringtonia acutangula (Freshwater
Mangrove)• Hibiscus tiliaceus (Beach Hibiscus)• Melaleuca cajuputi (medicine paperbark)• Terminalia erythrocarpa (Terminalia)
Mangrove reach (downstream of Aldridge Rd)
Mangroves: Ceriops tagal, Avicennia marina,
Lumnitzera racemosa, Excoecaria ovalis low closed
forest generally 2-7 m tall. Hinterland mangrove zone;
the species may occur together or as locally pure
stands.
Dominant flora:
• Avicennia marina (Grey Mangrove)• Rhizophora stylosa (Stilt Rooted Mangrove)• Saltmarsh (two species)
This reach is permanent estuarine water within a broad mangrove forest. A
sewer pipe crossing has created a small weir pool. Spring tides inundate the
pipe and penetrate much further upstream to near Jingili Water Gardens. At
low tide, rocky substrate is exposed downstream of the pipe. Steep muddy
banks with dense mangroves fringe the sinuous channel towards the ocean.
Water depth varies dramatically with tides, from a shallow, narrow, permanent
waterway to a deep, broad, expansive inundation of the mangrove forest.
Gastropods were common on trunks and support roots. Long Bums, Whelks
and Periwinkles appeared more dense where minor drainage depressions
trickled through the mangroves.
The surround mangrove forest is approximately 300-800 m wide. Two
species dominate the forest near the survey area, but others occur elsewhere
in the tidal flats. A variety of age classes show successful recruitment. A
gravel service track provides high ground for scatted saltmarsh succulents.
Current land use and historic reclamation adjacent to the mangroves prevents
saltmarsh establishment along the forest edge. Overall, the forest provides
good fish habitat, foraging grounds and bird habitat in an urban context. This
estuary also provides an important stepping stone between other mangroves
in Ludmilla and Buffalo Creek.
The terrestrial invertebrate sampling took place upstream at the tidal limit,
where mangroves transition to a brackish terrestrial community. Compared to
the broad mangrove forest downstream, the terrestrial habitat was narrow and
disturbed by mowing, roads, footpaths, gardens and other urban recreation
(dogs, bikes etc). Nonetheless, the habitat is part of a continuous green
corridor along Rapid Creek, connecting parks and bushland patches
surrounded by residential areas. This site would be used by fauna tolerant of
human activities and disturbance, whilst making use of the mixed habitat
(mangroves, woodland trees, cleared grassland, permanent water and woody
debris). A large colony of microbats utilises the riparian corridor as a flight
path and/or foraging habitat, as can be observed just after sunset. These
bats may roost in the mangrove forest, if suitable tree hollows occur, or inside
a large culvert.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Ludmilla Creek(headwaters)
Tributaries and drainsthrough golf course.
Sampling sites:
Fish: LC1 drainagechannel along northernboundary of golf course,March 2017.
Fish: LC1 LC2 drainagechannel 200 m south ofLC1 in golf course,March 2017.
Fish: LC3 creek atconfluence of twodrainage channels 300 mnorth of dam in golfcourse, March 2017.
Fish & vegetation: Lud-01-F golf course dam,Nov 2017.
Planted communities.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Ficus benjamina (Weeping Fig)• Leucaena leucocephala (Coffee Bush)• Nymphoides sp. (Water Lily)• Pandanus spiralis (Pandanus)
Four areas were sampled in the base golf course: three drainage lines and
one dam. The northernmost drainage channels had limited habitat value, as
they were short, trenched gullies with intermittent flows (airport runoff). No
fish were found in these drains. Cane Toad tadpoles were abundant in any
standing water on the golf course.
The third drainage line (LC3) received more flows that the other channels and
forms the main waterway leaving the site. During flows, fish are able to move
between a large dam and Bagot Rd (and further downstream). This shallow
waterway (2 m wide by <0.5 m deep) may provide foraging habitat for
piscivorous birds, amphibians and a small number of fish species.
The dam at the southern end of the golf course receives flows from the
airfield and provides permanent aquatic habitat. Habitat included open water
(approx. 0.75 ha by 1 m deep), woody debris, overhanging vegetation,
aquatic plants and soft sediment. Fish captured during the survey were
species common to small creeks. The Barramundi captured was possibly
relocated here for recreation or fish stocking purposes.
The riparian zone consisted of planted trees and shrubs on steep banks.
They would provide good bird roosting areas and refuge from the open-grass
fairways.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Ludmilla Creek(middle)
Estuary upstream of DickWard Drive.
Sampling sites:
Fish and vegetation:Lud-03-E at pool aboveDick Ward Drive and attrack crossing 150 mupstream.
Terrestrial invertebrates:Lud-03-T in transitionforest and woodlandadjacent to mangrovesnear Nemarluk Drive.
Terrestrial vertebrates:Lud-03-T in transitionforest and woodlandadjacent to mangrovesnear Nemarluk Drive.
Mangrove reach (upstream of Dick Ward Dr)
Mangroves: Rhizophora stylosa, Bruguiera exaristata,
Camptostemon schultzii closed forest to open forest.
This community grows along tidal creeks and includes
adjacent transitional zones.
Dominant flora:
• Avicennia marina (Grey Mangrove)• Rhizophora stylosa (Stilt Rooted Mangrove)
Transition and woodland (next to Nemarluk Dr)
Planted communities: mix of Pandanus, Eucalypt and
Monsoon forest.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Carallia brachiata (Carallia)• Heteropogon sp. (Black Speargrass)• Melaleuca cajuputi (Paperbark)• Melaleuca dealbata (Paperbark)• Pandanus spiralis (Pandanus)
This reach is permanent estuarine water within a broad mangrove forest. The
road crossing at Dick Ward Drive has created a small weir pool upstream (3
m wide by 0.5-4 m deep, depending on tide). High tides bring water through
the road culverts and upstream throughout the mangrove forest. At low tide,
the water retreats to a narrow pool (typically 2 m wide) trailing 150 m
upstream to a raised gravel track crossing with small culverts. Rocky
substrate is exposed downstream of the track. Gentle muddy banks with
dense mangroves fringe the channel. Water depth varies dramatically with
tides, from a shallow, narrow, permanent waterway to a deep, broad,
expansive inundation of the mangrove forest.
Gastropods were common on trunks and support roots.
The surround mangrove forest is approximately 400 m wide. Two species
dominate the forest in the survey area, but others occur in the tidal flats. A
variety of age classes show successful recruitment. A gravel service track
provides high ground, but dissects the forest and would influence local tidal
hydrology, potentially creating a barrier to small species freely moving
throughout the forest. Overall, the forest provides good fish habitat, foraging
grounds and bird habitat in an urban context. This estuary also provides an
important stepping stone between other mangroves in Darwin Harbour.
The terrestrial sampling occurred adjacent to the mangroves in a mix of
Paperbark, Pandanus and Eucalypt forests. This area forms a long but
narrow terrestrial fringe to the mangroves along Nemarluk Drive. Fauna
using this area are relatively restricted from moving to other similar habitats,
unless they are able to use mangroves or flight. Large trees and hollows
were lacking in the area. The saline soils expected this close to mangroves
would likely restrict vegetation species to occupy unique microhabitats, such
as a Melaleuca in a shallow wet depression next to a Eucalypt on a raised soil
mound. As such, fauna species using this habitat are likely to be generalists,
using any habitat when movement is constrained by mangroves and
residential land.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Ludmilla Creek (lower)
Estuary near boat ramp
Sampling sites:
Fish and vegetation:Lud-04-E in main tidalchannel, about 160 meither side of boat rampat Spot on Marine, Nov2017.
Mangroves: Coastal Rhizophora stylosa closed forest
to 16 m tall, commonly in pure stands forming shoreline
zone. Also, upstream and island is Rhizophora stylosa,
Bruguiera exaristata, Camptostemon schultzii closed
forest to open forest. This community grows along tidal
creeks and includes adjacent transitional zones.
Dominant flora:
• Avicennia marina (Grey Mangrove)• Padina sp. (Padina)• Rhizophora stylosa (Stilt Rooted Mangrove)
This reach is permanent estuarine water within a mangrove forest and tidal
sandflats. The left bank was heavily modified by the boat ramp and
stabilisation works along a boat compound. All other areas were relatively
undisturbed, including a broad mangrove forest and island splitting the
channel. Channel sediment is mostly coarse sand and gravel, with fast tidal
water moving finer sediment outwards onto the mangrove flats. Fish habitat
is abundant at high tide in the deep, broad channel (100 m) and flooded
mangroves. At low tide, habitat is dramatically reduced to a series of small
pools (1 m deep) and very shallow channel runs (20 cm deep by 20 m wide).
Gastropods were rare around this area, despite intensive searching on
mangrove roots and substrate on both banks, island and high tide limit.
The surround mangrove forest is approximately 800 m wide. Two species
dominate the forest in the survey area, but others occur in the tidal flats. A
variety of age classes show successful recruitment. Overall, the forest
provides good fish habitat, foraging grounds and bird habitat in an urban
context. This estuary also provides an important stepping stone between
other mangroves in Darwin Harbour.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Reichardt Creek (east)
Eastern tributarydownstream of TigerBrennan Drive.
Sampling sites:
Fish and vegetation: Rei-01-F 100 m either side ofdirt road crossing, Nov2017.
Pandanus Communities: Pandanus spiralis low
woodland to very low open woodland, with
Lophostemon lactifluus and Grevillea pteridifolia.
Ground layer dominated by mixed species grasses and
sedges.
Dominant flora:
• Barringtonia acutangula (FreshwaterMangrove)
• Carallia brachiata (Carallia)• Heteropogon sp. (Black Speargrass)• Melaleuca viridiflora (Broad-leaved Paperbark)• Pandanus spiralis (Pandanus)
This ephemeral freshwater stream had a narrow (1 m) channel and shallow
(<0.5 m) seasonal pools. No fish were observed or captured during site
visits. There was limited aquatic habitat due to small size, desiccation during
Dry Season and isolation from other freshwater creeks. Upstream of the
main road is defined by Pandanus woodland with an occasional channel. The
downstream portion has a defined channel but is short (400 m) before
entering the estuary. Diadromous fish species may explore the area during
the Wet Season, but are unlikely to depend on this small and ephemeral
habitat.
The surrounding riparian and terrestrial land was in reasonable condition, with
multi-strata native woodland, few weeds, variety of tree size classes (except
very large trees) and good connectivity to a broad woodland and Charles
Darwin National Park.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Reichardt Creek (west)
Reichardt Creek westerntributary downstreamTiger Brennan Drive.
Sampling sites:
Fish and vegetation: Rei-02-F from road to 500 mdownstream, Nov 2017.
Pandanus Communities: Pandanus spiralis low
woodland to very low open woodland, with
Lophostemon lactifluus and Grevillea pteridifolia.
Ground layer dominated by mixed species grasses and
sedges.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Carallia brachiata (Carallia)• Heteropogon sp. (Black Speargrass)• Melaleuca viridiflora (Broad-leaved Paperbark)• Pandanus spiralis (Pandanus)
This creek is similar in character to Rei-01, but with more surrounding
disturbance, artificially straightened channel, scouring and piped channel
upstream of Tiger Brennan Drive. This ephemeral creek has a narrow wetted
channel (<2 m) with shallow (<0.2 m) seasonal runs. No permanent pools
occur. No fish were observed or captured during site visits. There was
limited aquatic habitat due to small size, desiccation during Dry Season and
isolation from other freshwater creeks. The freshwater portion is piped
upstream beneath Winnellie. The open channel downstream of Tiger
Brennan Drive runs approximately 700 m through bushland to the estuary and
mangroves.
Vegetation surrounding the reach was heavily disturbed by an elevated
service track and weeds (especially Gamba Grass). Vegetation improved at
greater distance from the track, with good connectivity through the woodland
to Charles Darwin National Park.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Sadgroves Creek(upper)
Estuary downstream ofTiger Brennan Drive.
Sampling sites:
Fish and vegetation:Sad-01-E, from road to200 m downstream, Nov2017.
Mangroves: Rhizophora stylosa, Bruguiera exaristata,
Camptostemon schultzii closed forest to open forest.
This community grows along tidal creeks and includes
adjacent transitional zones.
• Avicennia marina (Grey Mangrove)• Rhizophora stylosa (Stilt Rooted Mangrove)
This tidal, narrow channel was approximately 3-5m wide. Depth was variable
with tides, ranging from almost empty (<10cm deep) to full inundation of the
mangrove forest. Aquatic habitat was driven by tides, with fish able to forage
at mid-high tide but pushed downstream at low tide. Molluscs inhabited the
mangrove roots and intertidal channel. The substrate was typically soft
marine sediment, except for a gravelly base close to culvert inflows from Tiger
Brennan Drive. The creek is piped upstream of sample site, beneath
Winnellie.
These mangroves form the edge of the greater harbour forest, providing
valuable refuge and habitat connectivity to aquatic and terrestrial fauna,
including invertebrates, fish, reptiles and birds. Land reclamation from roads
and adjacent suburbs has created steep batters with rock stabilisation. This
physical character is unfavourable to saltmarsh establishment, which would
usually occur between the mangroves and terrestrial environment.
Sadgroves Creek(middle)
Estuary upstream ofDinah Beach boat ramp.
Sampling sites:
Fish and vegetation:Sad-02-E 1,200 m alongsouth-to-west bend ofmain channel, Nov 2017.
Mangroves: Rhizophora stylosa, Bruguiera exaristata,
Camptostemon schultzii closed forest to open forest.
This community grows along tidal creeks and includes
adjacent transitional zones.
Dominant flora:
• Avicennia marina (Grey Mangrove)• Rhizophora stylosa (Stilt Rooted Mangrove)• Sonneratia alba (Mangrove Apple)
This large tidal arm of Darwin Harbour is surrounded by a dense mangrove
forest up to 1 km wide. The fish sampling occurred near small tidal branches
600 – 1200 m downstream of Tiger Brennan Drive. Crab sampling occurred
in deeper water for an additional 600 m. Fish sampling was timed with an
outgoing tide, to trap species as they retreated after foraging in the flooded
mangroves. The habitat here is typical of that found in tidal arms of the
harbour (shallow, muddy channels surrounded by dense mangroves),
although this creek is the closest to Darwin city, mooring zones and industrial
runoff. Fauna expected here are a wide range of marine fishes, gastropods
and wader birds. The mangrove forest could also be home to small
mammals, snakes, microbats and forest birds. Seagrass is not expected in
highly tidal and turbid areas, so the site is unlikely to attract Dugongs or
provide varied habitat for molluscs, sponges, crustaceans, etc.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Fire training area andbase (north)
Darwin InternationalAirport and northernbase woodland.
Sampling sites:
Terrestrial invertebrates& vegetation: DIA-01-Twoodland opposite firetraining area, Dec 2017.
Terrestrial vertebrates:DIA-01-T 500 m north-west of the invertebratesite, in woodland nearpatrol track, April 2018.
Eucalyptus Woodland (NVIS 2005, Level 3: Wilson
et al. 1990): Eucalyptus tetrodonta, Eucalyptus miniata,
Corymbia bleeseri, Livistona humilis, Planchonia
careya, Brachychiton paradoxus, Sorghum intrans,
Heteropogon triticeus, Sorghum plumosum.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Alstonia actinophylla (Milkwood)• Calytrix exstipulata (Turkey Bush)• Corymbia bleeseri (Bloodwood)• Cycas armstrongii (Cycad)• Delonix regina (Poinciana)*• Eucalyptus tetrodonta (Darwin Stringybark)
This woodland site is located north of the runways, between the fire training
area and northern perimeter fence. Terrestrial invertebrates and vegetation
were sampled within 100 m of the fire training area. Terrestrial vertebrates
were sampled in the same bushland patch but 500 m to the north-west (due
to access restrictions post Cyclone Marcus).
Vegetation was in reasonably good condition with moderate to dense tree
cover, and scattered shrubs and grasses in open areas. Shrubs were more
common around tracks and historically disturbed areas (e.g. borrow pits).
Tree age classes were variable up to about 30cm diameter, but few large
trees were present. This young and dense cohort could be a result of
destruction in 1974 (Cyclone Tracy) or other land clearing activities. A lack of
large trees has resulted in few tree hollows. The largest tree in the survey
area was knocked over two days prior to sampling (Cyclone Marcus). Habitat
is this area is mostly suited to small reptiles that depend on leaf litter, bark
fissures and logs. Where the canopy was thin, the grass cover and shrubs
provide good shelter and foraging habitat for ground mammals, such as
Bandicoots.
This Eucalypt woodland is connected to a swath of similar vegetation along
Osgood Drive. This patch links nearby habitats from the golf course to Rapid
Creek, broken by cleared grassland and vehicle tracks. The greater
woodland is an important patch in a heavily modified landscape (large cleared
airfield, buildings and shopping complex). The nearest water source is Rapid
Creek, approximately 1 km to the east.
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Habitat Area Vegetation community Habitat characteristics
Base (south)
Defence base woodlandalong Stuart Highway.
Terrestrial invertebrates& vegetation: DEF-01-Twoodland 750 west ofwater tower, Dec 2017.
Terrestrial vertebrates:DEF-01-T woodland 750west of water tower, April2018.
Eucalyptus Communities: Eucalyptus tetrodonta, E.
miniata woodland to low woodland, with mixed species
mid stratum and grassland understorey.
Dominant flora:
• Acacia auriculiformis (Northern Black Wattle)• Andropogon gayanus (Gamba Grass)*• Breynia cernua (Breynia)• Eucalyptus tetrodonta (Darwin Stringybark)• Pandanus spiralis (Pandanus)• Planchonia careya (Cocky Apple)
This woodland site is located between the Stuart Hwy and airfield, about 700
m east of a water tower. Terrestrial fauna were sampled either side of an
unsealed service track.
Vegetation south of the track was in reasonable condition, with few weeds
and a dense Eucalyptus canopy, expect were Gamba Grass had invaded
around the edges. Large trees and hollows were absent from the area,
typical of remnant savanna patches around Darwin. Vegetation north of the
track had a sparser canopy cover, with climbing weeds dominating the ground
cover. Habitat in this area was similar to site DIA-01, and mostly suited to
small reptiles that depend on leaf litter, bark fissures and logs. Where the
canopy was thin, the grass cover and shrubs provided good shelter and
foraging habitat for ground mammals, such as Bandicoots.
The woodland patch is part of a larger, disconnected green belt running along
the Stuart Hwy. Fauna are able to move freely between woodland patches if
they cross several unsealed tracks and cleared grassland. The nearest
accessible waterway is the headwaters of Rapid Creek, approximately 1.5 km
to the north-east.
* weed species
Vegetation community based on: (Darwin to Palmerston Region - Remnant Vegetation Survey, Brock 1995) and dominant flora (ELA observation)
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Rapid Creek (northern headwater) Dry creek bed at Rap-01-T Woodland at Rap-01-T
Woodland Dry creek bed
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Rapid Creek (southern headwater)
Wattle, gum and pandanus woodland in the lower Woodland Walk Upper Woodland Walk
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Southern headwaters in wet season Southern headwaters in dry season
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Rapid Creek (upper)
Around spillway near resort.
Permanent water above Spillway Earthen drain that directs stormwater to Rapid Creek
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Below Spillway Pandanus woodland in floodplain
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Rapid Creek (middle)
From Henry Wrigley Drive to weir 400 m downstream of McMillians Road.
Large earthen drain from DIA prior to entering Rapid Creek Undercut banks with exposed roots
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Monsson forest Creek near gauging weir
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Rapid Creek (lower)
From red footbridge aligned with Carrington Road to below Power & Water pipe crossing 600 m downstream of Trower Road.
Mangroves at the pipe crossing Mangroves at the pipe crossing
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Upper tidal transition zone Woodland above mangroves
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Ludmilla Creek (headwaters)
Tributaries and drains through golf course.
Northern drain across the golf course Dam in golf course
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Ludmilla Creek (middle)
Estuary upstream of Dick Ward Drive.
Mangroves upstream of Dick Ward Drive Mangroves at the track crossing
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Woodland at the fringes of mangroves
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Ludmilla Creek (lower)
Estuary near boat ramp
Channel at low tide Mangroves at low tide
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Reichardt Creek (east)
Eastern tributary downstream of Tiger Brennan Drive.
Creek Woodland showing pandanus and speargrass
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Reichardt Creek (west)
Reichardt Creek western tributary downstream Tiger Brennan Drive.
Lower creek Upper creek
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Sadgroves Creek (upper)
Estuary downstream of Tiger Brennan Drive.
Mangroves at low tide Mangroves at low tide
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Sadgroves Creek (middle)
Estuary upstream of Dinah Beach boat ramp.
Channel at outgoing tide Mangroves at high tide
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Fire training area and base (north)
Darwin International Airport and northern base woodland.
Northern Base woodland Woodland and grassland opposite current fire training ground
Appendix D – Habitat descriptions
RAAF Base Darwin PFAS Ecological Risk Assessment Coffey
Site (Darwin)
Base (south)
Defence base woodland along Stuart Highway.
Typical Southern base woodland