Banksia Aemula - Distribution and Habitat

Distribution and Habitat

Banksia aemula is found along the east coast of Australia from around 70 km (45 mi) north of Bundaberg in central Queensland down to Sydney. Specifically, its southernmost occurrence is at La Perouse on the northern side of Botany Bay. It is also found on Fraser, Moreton and North Stradbroke Islands. Almost all populations are within a few kilometres of the coast, except for one at Agnes Banks in western Sydney, and two just north and south of Grafton at Coaldale and Glenreagh, and a last around 30 km (19 mi) southwest of Bundaberg.

Banksia aemula is most commonly found in deep sandy soils, either on dunes or flattish areas which may be seasonally wet. On coastal dunes in southern Queensland, it replaces Banksia serrata, which occupies the same niche to the south. The latter areas, with open woodland or heathland, are known as wallum. In Queensland it is found with Banksia robur, with the latter species found in flatter wetter areas and B. aemula found on rises. It is also found with Banksia oblongifolia in Queensland. In some areas of wallum, it may grow as a small tree, along with mallee forms of the red bloodwood (Corymbia gummifera). In Cooloola National Park, it is an occasional emergent plant (along with Melaleuca quinquenervia and Eucalyptus umbra) in closed graminoid heathland, a community of shrubs 0.5–2 m (1.5–7 ft) high containing Xanthorrhoea fulva, Empodisma minus, Petrophile shirleyae, and Hakea and Leptospermum species. On the New South Wales Central Coast, it generally grows as a 1–2 m (3–7 ft) high shrub and is a canopy component of Banksia aemula open heathland, located on coastal headlands on highly leached Pleistocene white sands overlying Triassic and Permian strata. Areas include Wybung Head in Munmorah State Conservation Area, and near Myall Lakes. Other plants it grows in association with include Ricinocarpos pinifolius, Brachyloma daphnoides, Dillwynia glaberrima, D. retorta, Allocasuarina distyla, Bossiaea ensata, Aotus ericoides, Phyllota phylicoides, and Empodisma minus. Sandmining has eradicated much of the community around Redhead. In less leached yellower sands, the community (and B. aemula) is replaced by a taller heath containing B. serrata and B. oblongifolia.

At the southern end of its range, Banksia aemula is a component of the Eastern Suburbs Banksia Scrub (ESBS), designated an endangered ecological community. This community is found on younger, windblown sands than the heathlands to the north.

The Agnes Banks Woodland in western Sydney has been recognised by the New South Wales Government as an Endangered Ecological Community. Here Banksia aemula is an understory plant in low open woodland, with scribbly gum (Eucalyptus sclerophylla), narrow-leaved apple (Angophora bakeri) and B. serrata as canopy trees, and B. oblongifolia, Conospermum taxifolium, Ricinocarpus pinifolius, Dillwynia sericea and nodding geebung (Persoonia nutans) as other understory species.

On North Stradbroke Island, Banksia aemula is one of three canopy tree species of Eucalyptus signata dominated forest 12–15 m (40–50 ft) high, the third species being E. umbra. This forest is found on a ridge 100 m (400 ft) above sea level formed from an ancient sand dune. Here bracken (Pteridium esculentum) dominates the understory. Other tall shrubs associated include Persoonia cornifolia and Acacia concurrens. Here individual wallum banksias were measured at 8.3–12.1 m (25–40 ft) high, with a maximum diameter at breast height of 44 cm (20 in).