Natural Area Survey - Vegetation Communities  

A vegetation community is a particular group of plants that make up a vegetation type or unit. Warringah has 37 different vegetation communities. Each community contains different flora species and provides potential habitat for a range of fauna.

Amost half (41%) of Warringah's native vegetation has been lost since 1750. The impact of clearing has been very uneven, with some vegetation communities far more affected than others in areas where land has become suitable for urban development.

Very little of Warringah's native vegetation now remains within four kilometres of the coast, where significant development has taken place. As a result, vegetation communities found in this area have been greatly reduced in size. Some of the Warringah vegetation communities are now so rare that they are listed as 'endangered' under the NSW Threatened Species Conservation Act 1995.

As the native vegetation of Warringah becomes more and more fragmented, it is increasingly important to maintain and re-establish vegetation links between the larger areas of remnant bushland. These links, called 'wildlife corridors', allow native animals to move between the small pockets of bush that remain.

The map of Warringah's vegetation in 2000 (PDF, 954KB) compared with the map of Warringah from 1750 (819KB) clearly shows that a large amount of vegetation has been lost and that there are now many fragmented pieces of bushland in Warringah. It is important that the local community continues to preserve bushland wherever possible, but particularly in areas where there are limited examples remaining of a particular type of vegetation.

Warringah's 37 different vegetation communities are broadly grouped into the following vegetation units.

Estuarine Complex

Estuarine Complex is a vegetation unit that occurs in estuarine (salt) water conditions particularly around Dee Why and Narrabeen Lagoons. Soil in these areas is waterlogged which plants have adapted to. Within this unit are four vegetation communities - Mangrove Swamp, Swamp Oak Forest, Saltmarsh and Seagrass Meadow. Seagrass Meadow plays an important role in estuaries as it provides food, shelter and nursery grounds for many aquatic animals.

Coastal Clay Heath

Coastal Clay Heath grows on exposed coastal headlands on the soil type Narrabeen Group Shale - the soil layer that lies below Hawkesbury Sandstone. This vegetation unit is restricted to Long Reef Headland and Collaroy Escarpment. Within this unit there are four vegetation communities - Coastal Banksia-teatree Scrub, Themeda Grassland, Narrabeen Escaprment Scrub and Lomandra Sedgeland.

Narrabeen Slopes Forest

Narrabeen Slopes Forest occurs on the soil type Narrabeen Group Shale. In comprison with the sandy, infertile soils of Hawkesbury Sandstone, shale is a clay-rich soil with a fine texture and is more fertile. Narrabeen Slopes Forest is made up of tall trees and moist understorey species and is found in sheltered locations at Cottage Point, Jamieson Park and Anzac Avenue Reserve. This vegetation is rare because it only occurs in areas where Narrabeen Shale outcrops ocur. There are two vegetation communities within this unit - Rough-barked Apple-forest Oak Forest and Bangalay Slopes Forest.

Duffys Forest

Duffys Forest is an endangered ecological community listed under the Threatened Species Conservation Act. Duffys Forest is very rare and makes up only 4% of Warringah's bushland. The soil of this community is slightly more fertile than the soil of other types of sandstone vegetation resulting in generally taller trees and grassier understorey. Duffys Forest is also habitat for many threatened plants including the endangered shrub Grevillea caleyi. Warringah contains most of the remaining Duffys Forest and Grevillea caleyi in the whole of Sydney. The three vegetation communities in this unit are - Silvertop Ash-brown Stringbark Forest, Blackbutt-turpentine Forest and Angophora-white Mahogany Forest.

Coastal Dune Forest

This vegetation unit is found growing on sand dunes along coastal beaches. In Warringah, only 7% of the original extent of this vegetation now remains along the western side of Dee Why Lagoon and a small area around Curl Curl Lagoon. There is one vegetation community within this unit - Coastal Banksia-eucalypt Scrub. Two plants species foundin this vegetatation - Banksia integrifolia (Coast Banksia) and Eucalyptus robusta (Swamp Mahogany) - are a major winter food source for nectar-feeding fauna such as the threatened Regent Honeyeater and Swift Parrot.

Coastal Dune Heath

Coastal Dune Heath is widespread along the coastline and makes up 0.9% of Warringah's bushland. There are two vegetation communities within this unit - Spinifex Grassland and Coastal Wattle Heath. Both communities occur on sand dunes with Spinifex Grasslands growing on the seaward edge of the dune and Coastal Wattle Heath on the landward side.

Sydney Sandstone Gully Forest

Sydney Sandstone Gully Forest makes up about 20% of bushland in Warringah. It is common throughout the entire area and occurs on sandy soils made from Hawkesbury Sandstone. Sandstone Gully Forest usually grows in tall forest-like formations within gullies and on sheltered slopes where the soils are deeper and richer.

There are four different vegetation communities within this unit and all four have different dominant species - Peppermint-angophora Forest, Coachwood Rainforest, Forest Oak Forest and Tall Open-forest with Closed-forest Understorey. The Forst Oak community is only found at Allenby Park within Warringah and is a major food source for the threatened Glossy Black Cockatoo, while Coachwood Rainforest provides habitat for the threatened Powerful Owl.

Sydney Sandstone Ridgetop Woodland

Sydney Sandstone Ridgetop Woodland grows on sandy soils made from Hawkesbury Sandstone and is found on plateaus and ridges. This unit makes up over 41% of all bushland and is the most common type of bushland found in Warringah. There are three different vegetation communities within this unit and all three have different dominant speceis - Bloodwood-scribbly Gum Woodland, Narrow-leaved Scribbly Gum Woodland and Angophora Woodland. Angophara Woodland is an important vegetation community as it provides habitat for many threatened plant and animal species including the Glossy Black Cockatoo and the Poweful Owl.

Coastal Sandstone Heath

This vegetation unit occurs on the sandy soils of Hawkesbury Sandstone geology. Plant species growing on this soil type have adapted to shallow, infertile and dry soild conditions. Vegetation communities growing on sandstone geology are known to have a high level of species diversity and are habitat for a number of threatened plants and animals. This vegetation unit makes up over 21% of all bushland and is one of the most common types of bushland found in Warringah. This unit has five different vegetation communities - Sandstone Heath, Sandstone Swamp, Sandstone Headland Heath, Yellow-top Ash Mallee and Heart-leaved Stringybark Mallee.

Coastal Swamp Forest Complex

This vegetation unit is an endangered ecological community listed under the Threatened Species Conservation Act. Coastal Swamp Forest Complex makes up only 1.8% of all bushland found in Warringah. It is found around swampy saline and waterlogged areas, particularly around the margins of estuaries and coastal lagoons such as Narrabeen and Dee Why. There are seven getation communities within this unit - Estuarine Reedland, Estuarine Paperbark Scrub, Swamp Mahogany Forest, Bangalay Alluvial Forest, Palm Woodland, Paper Bark Swamp and Water Fern Swamp.

These vegetaion communities are extremely rare within Warringah and many are not found in National Parks. They contain many threatened plants species and are important habitat for threatened fauna species such as the Australiasian Bittern, Osprey, Black Bittern, Swift Parrot, Regent Honeyeater, Spotted-tailed Quoll and Greater Broad-nosed Bat.

Coastal Freshwater Swamp

This vegetation unit - also called Sydney Freshwater Wetlands - is an endangered ecological community listed under the Threatened Species Conservation Act. This vegetation unit is made up of dense strands of reeds, sedges and other wetland plants and is surrounded by low trees and shrubs. There are two vegetation communities within this unit - Coastal Freshwater Lagoon Swamp and Coastal Dune Swamp. Both types of vegetation are rare in Warringah and in the Sydney region. In Warringah, Coastal Freshwater Lagoon Swamp is only found at one small lagoon on the floodplain of Deep Creek and coastal Dune Swamp on the western side of Dee Why Lagoon. Both communities provide potential habitat for threatened fauna species including the Black Bittern and the Green and Golden Bell Frog.

Derived Communities

Derived Communities occur as a result of human modifications to the natural environment which result in changes to the original vegetation. In Warringah there are two Derived Communities - Yellow Bloodwood-grey Gum Forest and Artificial Wetlands. Yellow Bloodwood Grey Gum Forest is a highly modified form of Duffys Forest that has been affected by past distubance and inappropriate plantings. There is only one example of this in Warringah, located at the Sydney East Substation at Belorse. Artificial Wetlands were created at Manly Dam when Curl Curl Creek was dammed to create the artifical waterway. The vegetation now resembles vegetation found in Freshwater Lagoon Swamps.

Natural Area Survey - Vegetation Communities and Plant Species

• Contents, Introduction and Table 1. Native Vegetation Communties of the Warringah LGA.pdf
• Vegetation community descriptions pages 7-18.pdf
• Vegetation community descriptions pages 19-33.pdf
• Vegetation community descriptions pages 34-45.pdf
• Corresponding communities in Ku-ring-gai Chase and Garigal National Parks