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Ecology of Sydney facts for kids

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Western Sydney (Badgerys Creek) Airport site - Anton Rd
In 1820s, Peter Cunningham described the western plains of Sydney as "a fine timbered country, perfectly clear of bush...without any impediment in the shape of rocks, scrubs, or close forest".

The ecology of Sydney, located in the state of New South Wales, Australia, is diverse for its size, where it would mainly feature biomes such as grassy woodlands and some sclerophyll forests, with a few pockets of mallee shrublands, subtropical and temperate rainforests (evergreen), heathlands, and wetlands. The combination of climate, topography, moisture, and soil influence the dispersion of these ecological communities across a height gradient from 0 to 200 metres (0 to 700 ft). There are many hiking trails, paved and unpaved roads for exploring the many different biomes and ecosystems.

Grassy woodlands, the most predominant biome in the Sydney region, mainly occur in the Cumberland Plain west of Sydney CBD, which generally feature eucalyptus trees that are usually in open, dry sclerophyll woodland areas with shrubs (typically wattles, callistemons, grevilleas and banksias) and sparse grass in the understory, reminiscent of Mediterranean forests. The plants in this community tend to have rough and spiky leaves, as they're grown in areas with low soil fertility. Wet sclerophyll forests, which are part of Eastern Australian temperate forests, have narrow, relatively tall, dense trees with a lush, moist understorey of fleecy shrubs and tree ferns. They are mainly found in the wetter areas, such as Forest District and the North Shore.

The Sydney Turpentine-Ironbark Forest, one of six main indigenous forest communities of Sydney, is an example of a dry sclerophyll forest, containing trees around 20–30 metres tall, with ground cover composed of flowering shrubs and native grasses. The Blue Gum High Forest, strictly found in northern parts of Sydney, is a wet sclerophyll forest example, where the annual rainfall is over 1100 mm (43 in), with its trees between 20 and 40 metres tall.

It has been calculated that around 98,000 hectares of native vegetation remains in the Sydney metropolitan area, shaping the geography of Sydney, about half of what is likely to have been existing at the time of European arrival.

Historical description

In 1819, British settler William Wentworth described Sydney's vegetation and landform in great detail:

For the distance of 5 mi (8.0 km) to 6 mi (9.7 km) from the coast, the land is in general extremely barren, being a poor hungry sand, thickly studded with rocks. A few miserable stunted gums, and a dwarf underwood, are the richest productions of the best part of it; while the rest never gives birth to a tree at all, and is only covered with low flowering shrubs, whose infinite diversity, however, and extraordinary beauty, render this wild heath the most interesting part of the country for the botanist, and make even the less scientific beholder forget the nakedness and sterility of the scene.

Beyond this barren waste, which thus forms a girdle to the coast, the country suddenly begins to improve. The soil changes to a thin layer of vegetable mould, resting on a stratum of yellow clay, which is again supported by a deep bed of schistus. The trees of the forest are here of the most stately dimensions. Full sized gums and iron barks, along side of which the loftiest trees in this country would appear as pigmies, with the beefwood tree, or as it is generally termed, the forest oak, which is of much humbler growth, are the usual timber. The forest is extremely thick, but there is little or no underwood.

At this distance, however, the aspect of the country begins rapidly to improve. The forest is less thick, and the trees in general are of another description; the iron barks, yellow gums, and forest oaks disappearing, and the stringy barks, blue gums, and box trees, generally usurping their stead. When you have advanced about 4 mi (6.4 km) further into the interior, you are at length gratified with the appearance of a country truly beautiful. An endless variety of hill and dale, clothed in the most luxuriant herbage, and covered with bleating flocks and lowing herds, at length indicate that you are in regions fit to be inhabited by civilized man. The soil has no longer the stamp of barrenness. A rich loam resting on a substratum of fat red clay, several feet in depth, is found even on the tops of the highest hills, which in general do not yield in fertility to the valleys. The timber, strange as it may appear, is of inferior size, though still of the same nature, i. e. blue gum, box, and stringy bark. There is no underwood, and the number of trees upon an acre do not upon an average exceed thirty. They are, in fact, so thin, that a person may gallop without difficulty in every direction.


A warm-temperate rainforest in Ku-ring-gai, which harbours palm trees.
Heathland on a road in Botany Bay National Park.
Blue Gum Walk, a wet sclerophyll forest in Berowra Valley National Park
  • Rainforests
  • Wet scleropyhll forests
  • Grassy Woodlands
    • Cumberland Plain Woodland – These are shrub and grass eucalyptus communities located in areas of low to moderate rainfall (less than 950 millimetres annually) and are most commonly found in large parts of the Sydney metropolitan area, namely in Western Sydney or the Cumberland Plain. Moist Shale Woodlands also exist within this biome, but they're distinguished by their lusher plant habitats. It is a dry woodland remnant containing waxy-leaved shrubs, twiners, herbs and small trees in a grassy understorey. It has a number of sub-regions: Moist Shale Woodlands, Western Sydney dry rainforest, Shale gravel transition forest, and Shale gravel transition forest, among others.
  • Dry sclerophyll forests
    • Sydney Coastal Dry Sclerophyll Forests – Predominant on the northeast parts of the Woronora Plateau on ridgelines within the Royal, Heathcote and Dharawal national parks and Garawarra State Conservation Area in southern Sydney. It is also present in north of Sydney Harbour and extends to both sides of the Hawkesbury River in Northern Beaches and Hornsby LGA's and Pennant Hills.
    • Sydney Hinterland Dry Sclerophyll Forests – Found in the drier parts (less than 950 mm) of the Woronora Plateau, also in Appin, Sandy Point, pockets in the southwestern edges of the Cumberland Plain (on the doorsteps of the Blue Mountains), and on the foreshores of the Hawkesbury River, it features 10–25 m tall eucalyptus trees with ostensible sclerophyll shrub understorey and open groundcover of sclerophyll sedges.
      • Cooks River/Castlereagh ironbark forest – Found in Castlereagh and Holsworthy, and a few remnants in the cities of Auburn, Bankstown and Liverpool, it is an ironbark shrub-grass forest located in western Sydney that sit on gravelly-clay soils and is made up of a moderately tall open eucalyptus forest or woodland to a low compact brush of paperbarks with nascent eucalypts. Broad-leaved ironbark (Eucalyptus fibrosa) is the most commonly spotted tree.
    • Sydney Sand Flats Dry Sclerophyll Forests – Present in northern Holsworthy with smaller examples at Rookwood and Villawood and is dominated by Eucalyptus sclerophylla.
    • Coastal Dune Dry Sclerophyll Forests – Examples are found at Bundeena, Kurnell and La Perouse in southern Sydney containing a collection of sclerophyllous shrub and heath species and a ferny ground cover.
  • Heathlands
    • Wallum Sand Heaths – Present in Pleistocene sand dunes sitting high on sandstone cliff tops between Bundeena in Royal NP, Woollahra, Kurnell peninsula, Narrabeen and Sydney Heads which contain Allocasuarina distyla, Banksia serrata and Banksia aemula. There are also a wide variety of woody species such as tea-trees, grevilleas, peas and wattles. The ground layer comprises on open cover of sedges and forbs.
    • Sydney Coastal Heaths – Found extensively in the Sydney metropolitan area and in the eastern parts of the Woronora and Hornsby plateaus particularly in Royal and Ku-ring-gai national parks with prominence of Eucalyptus luehmanniana.
    • Coastal Headland Heaths – Found in and around Garie Beach on the outskirts of southern Sydney, near Royal NP.
  • Freshwater Wetlands
    • Castlereagh swamp woodland – A swampy sclerophyll forest affiliated with sporadically flooded soils containing Tertiary, Holocene and Quaternary sand deposits. It is found in low-elevated areas of Liverpool and in Voyager Point, and is made up of moderate to heavy cover of paperbark trees.
    • Coastal Heath Swamps – Common in Holsworthy defense area, Woronora catchment area and the Hornsby plateau including Garigal and Ku-ring-gai Chase national parks.
    • Coastal Freshwater Lagoons – Occurs on poorly drained alluvial flats and sand depressions and may be surrounded by broad-leaved cumbungi (Typha orientalis).
  • Forested wetlands
    • Sydney coastal river-flat forest – Found on the river flats of the coastal floodplains in most parts of the plain that has rivers or creeks. It has an open tree layer of eucalypts which may surpass 40 m in height.
    • Coastal Swamp Forests – Occupies the low-lying coastal river flats, swamps and sand depressions, which are mostly cleared from the Sydney metropolitan area, but still exist in places like Georges River National Park, Milperra, Chipping Norton, Prospect Creek and Kurnell in southeastern Sydney, and Wheeler Heights, Narrabeen and Dee Why in the Northern Beaches.
    • Coastal Floodplain Wetlands – They cover a series of eucalypt and casuarina dominated communities found on low-lying coastal alluvial soils, such as in Georges River and its tributaries in northern Woronora and the lowlands of Blue Mountains. They are dominated by Microlaena stipoides.
    • Eastern Riverine Forests – Many riparian scrubs are found on rocky creeks that are enclosed with coarse sandy alluvial deposits with common vegetation being Tristaniopsis laurina.
  • Saline Wetlands
    • Mangrove Swamps – Common in Towra, they're a basic community dominated by either Avicennia marina or Aegiceras corniculatum.
    • Saltmarshes – Usually located on estuarine alluvial soils, small tracts also exist on headlands exposed to prevailing sea spray.
    • Seagrass Meadows – Occurring on sandy nether of coastal estuaries and bays, they include a number of subaqueous aquatic species, such as eel grass (Zostera spp) and sea grass (Posidonia australis).

Complete list

Biomes Eco-communities
Wet Sclerophyll Forests
Grassy Woodlands
Coastal Grasslands
Dry Sclerophyll Forests
Freshwater Wetlands
Forested Wetlands
Saline Wetlands


Tree species
Sydney red gum, a common woodland and forest tree of Eastern Australia.
Grey box, a medium-sized to occasionally tall tree with rough, persistent bark on the lower trunk.
White feather honeymyrtle, a paperbark tree with lance-shaped leaves that is covered with creamy-coloured flowers in summer.
Casuarina trees are the most widespread in Sydney after the eucalyptus.
Narrow-leaved bottlebrush is a shrub which has a rigid point, and red flower spikes in late spring or early summer.
The curtain fig is one of the most common street trees in Sydney and is used as a shade tree.
A commonly sighted tree, the Australian silver oak displays yellowish orange, or sometimes reddish flowers in spring.

The most widespread eucalyptus species in the Sydney region include:

Non-eucalyptus tree species:

Common shrub species include, but are not limited to:


Introduced trees:

Introduced shrubs (most of are invasive species):

  • Thunbergia grandiflora (blue skyflower)
  • Alternanthera philoxeroides (alligator weed)
  • Anredera cordifolia (Madeira-vine)
  • Asparagus aethiopicus (asparagus fern)
  • Lantana camara (West Indian lantana)
  • Cestrum nocturnum (night-blooming jasmine)
  • Senna septemtrionalis (arsenic bush)
  • Ochna serrulata (Mickey Mouse plant)
  • Ligustrum sinense (small-leaved privet)
  • Solanum mauritianum (wild tobacco bush)
  • Talinum paniculatum (jewels-of-opar)
  • Ricinus communis (castor oil plant)


Common native species
Commonly sighted in Sydney, Australian magpies are known for their distinctive, "gargling" calls.
Noisy miners are ubiquitous in urban, suburban and woodland areas.
Australian ravens are notable for their screechy, high pitched ah-ah-aaaah calls.
The pied currawong is a common bird in the plain and is usually seen in urban forests and backyards.
Grey-headed flying-foxes are found in suburban woods.
Blue-tongues are the predominant skink species in Sydney.
Redback spiders, which are venomous, became widespread in the urban areas by the early 20th century.
Grey butcherbirds, known for their frisky song, are found in woodlands, acacia shrublands and residential townships.
Crested pigeons are usually found in the open grasslands and wooded areas of the plain.
The spotted dove is a small, long-tailed pigeon that was introduced in Australia in the 1860s.
The snake-eyed skink is often seen on vertical surfaces such trees, fences and walls.
Sydney huntsman spiders are found in tree logs, barks and rock walls.

The fauna of the Sydney area is diverse and its urban area is home to variety of bird and insect species, and also a few bat, arachnid and amphibian species. Introduced birds such as the house sparrow, common myna and feral pigeon are ubiquitous in the CBD areas of Sydney. Moreover, possums, bandicoots, rabbits, feral cats, lizards, snakes and frogs may also be present in the urban environment, albeit seldom in city centers.

About 40 species of reptiles are found in the Sydney region and 30 bird species exist in the urban areas. Sydney's outer suburbs, namely those adjacent to large parks, have a great diversity of wildlife. Since European settlement and the subsequent bushland clearing for the increasing population, 60% of the original mammals are now considered endangered or vulnerable, and many reptile species are experiencing population diminution and are becoming elusive.


This list includes bird species that are widespread in the Sydney metropolitan area:

Although not commonly spotted, these birds are also present in Sydney:

This list includes mammal, reptile and amphibian species that are spotted in the Sydney urban area:


This list includes insect, spider and centipede species that are commonly present in Sydney:

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