Appendix D Habitat Description - Department of Defence€¦ · Appendix D – Habitat descriptions...

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.




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.







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.






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.






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.




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.



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.




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.




Reichardt Creek (east)

Eastern tributarydownstream of TigerBrennan Drive.

Sampling sites:

Fish and vegetation: Rei-01-F 100 m either side ofdirt road crossing, Nov2017.





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.




Reichardt Creek (west)

Reichardt Creek westerntributary downstreamTiger Brennan Drive.

Sampling sites:

Fish and vegetation: Rei-02-F from road to 500 mdownstream, Nov 2017.





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.




Sadgroves Creek(upper)

Estuary downstream ofTiger Brennan Drive.

Sampling sites:

Fish and vegetation:Sad-01-E, from road to200 m downstream, Nov2017.





• 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.





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.




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.




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)



Site (Darwin)

Rapid Creek (northern headwater) Dry creek bed at Rap-01-T Woodland at Rap-01-T

Woodland Dry creek bed



Rapid Creek (southern headwater)

Wattle, gum and pandanus woodland in the lower Woodland Walk Upper Woodland Walk



Site (Darwin)

Southern headwaters in wet season Southern headwaters in dry season



Rapid Creek (upper)

Around spillway near resort.

Permanent water above Spillway Earthen drain that directs stormwater to Rapid Creek



Site (Darwin)

Below Spillway Pandanus woodland in floodplain



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



Site (Darwin)

Monsson forest Creek near gauging weir



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



Site (Darwin)

Upper tidal transition zone Woodland above mangroves



Site (Darwin)

Ludmilla Creek (headwaters)

Tributaries and drains through golf course.

Northern drain across the golf course Dam in golf course



Ludmilla Creek (middle)

Estuary upstream of Dick Ward Drive.

Mangroves upstream of Dick Ward Drive Mangroves at the track crossing



Site (Darwin)

Woodland at the fringes of mangroves



Site (Darwin)

Ludmilla Creek (lower)

Estuary near boat ramp

Channel at low tide Mangroves at low tide



Site (Darwin)

Reichardt Creek (east)

Eastern tributary downstream of Tiger Brennan Drive.

Creek Woodland showing pandanus and speargrass



Site (Darwin)

Reichardt Creek (west)

Reichardt Creek western tributary downstream Tiger Brennan Drive.

Lower creek Upper creek



Site (Darwin)

Sadgroves Creek (upper)

Estuary downstream of Tiger Brennan Drive.

Mangroves at low tide Mangroves at low tide



Site (Darwin)

Sadgroves Creek (middle)

Estuary upstream of Dinah Beach boat ramp.

Channel at outgoing tide Mangroves at high tide



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



Site (Darwin)

Base (south)

Defence base woodland along Stuart Highway.

Typical Southern base woodland

Appendix D Habitat Description - Department of Defence€¦ · Appendix D – Habitat descriptions...

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