Manly Dam

Manly Dam catchment forms a large valley with an underlying geology of Hawkesbury sandstone. It is rich in plant life with over 300 native plant species, including 18 diferent native orchids.

It is also an excellent example of the typical vegetation communties found on Hawkesbury sandstone in Warringah, such as Sandstone Heath, Silvertop Ash-Brown Stringybark Forest and Duffy's Forest.

Unfortunately, there are also around 100 weed species that have invaded the park which are threatening the native flora.

Vegetation communities

Bloodwood Scribbly Gum Woodland is the most common vegetation community in Warringah. It is typically made up of medium sized trees with sparse canopy cover and supports two threatened species, Rice Flower (Pimelea curviflora) and Black-eyed Susan (Tetratheca glandulosa), and three rare species, Narrow-leaved apple, Nodding Raspwort, Stephenson's Platsace. The dominant trees are Red Bloodwood and Broad-leaved Scribbly Gum. Also occuring are Sandstone Stringybark and Silvertop Ash.

Silvertop Ash-Brown Stringybark Forest is an endangered vegetation community. It occurs as open forest or woodland on ridgetops where there is fertile shale areas and supports two threatened species, Rice Flower and Black-eyed Susan. Dominant trees are Silvertop Ash and Brown Stringybark. Also occurring are Sydney Redgum, Red Bloodwood and Broad-leaved Scribbly Gum.

Peppermint-Angophora Forest is widespread in Warringah and occurs as open forest and woodland. Dominant trees includes Sydney Red Gum and Sydney Peppermint. Also occuring are Red Bloodwood and Silvertop Ash. Habitat for this community include gullies, sheltered slopes and sandstone outcrops.

 

Freshwater Lagoon Swamp is a rare vegetation community in Sydney and generally consists of dense stands of reeds, sedges and other wetland plants, with a fringing zone of low trees and shrubs. Manly Dam is a manmade body of water, therefore the Manly Dam Freshwater lagoon swamp is an unusual example. Fringing shrubs include Viminaria juncea.

Sandstone Heath is a common vegetation community in Warringah - the further from the coast you travel the less common it is. In Warringah sandstone heath varies from open heath to closed scrub. Shrub species include Allocasuarina distyla, Angophora hispida, Banksia ericifolia, Epacris pulchella, Grevillea speciosa, Hakea teretifolia, Kunzea ambigua and Leptospermum squarrosum.

Sandstone Swamp is an uncommon vegetation type found scattered throughout Warringah. It occurs of the wettest sites on Hawkesbury sandstone either as hanging swamps or valley swamps. Shrub species include Baeckea imbricata, Banksia ercifolia, Bauera rubiodes, Dillwynia floribunda, Epacris obtusifolia, Hakea teretifolia, and Leptospermum squarrosum.

 

Weed species

Around 100 weed species have been recorded at Manly Dam including asparagus fern, lantana, cassia, cobblers pegs, cotoneaster, fishbone fern, japanese honeysuckle, morning glory, ludwigia, pampas grass, privet, turkey rhubarb, canna lilly, ginger lilly, blackberry, madeira vine, tobacco bush and wandering jew.

Bushcare volunteers and professional bush regenerators rehabilitate Manly Dam reserve on a regular basis in the aim of returning it back to healthy bushland. Anyone can become a bushcare volunteer. There is no age limit and there are activities to suit all levels of participation. Click on the link for more details.

There are also several things you can do at home to stop the spread of weeds into bushland, such as:

• removing noxious and environmental weeds from your garden
• selceting plants for your garden that won't invade local bushland
• disposing of weeds correctly
• washing soil from your boots and tyres before entering bushland reserves to prevent the spread of root rot

Click on the link to identify noxious and environmental weeds found in Warringah.