) feasting on B. integrifolia
subsp. integrifolia'',
Waverley NSW Banksias are heavy producers of
nectar, making them an important source of food for
nectivorous animals, including
honeyeaters and small mammals such as rodents,
antechinus,
honey possums,
pygmy possums,
gliders and
bats. Many of these animals play a role in pollination of
Banksia. Various studies have shown mammals and birds to be important pollinators. In 1978, Carpenter observed that some banksias had a stronger odour at night, possibly to attract nocturnal mammal pollinators. Other associated fauna include the
larvae of
moths (such as the
Dryandra Moth) and
weevils, which burrow into the "cones" to eat the seeds and
pupate in the follicles; and
birds such as
cockatoos, who break off the "cones" to eat both the seeds and the
insect larvae. A number of
Banksia species are considered rare or endangered. These include
B. brownii (feather-leaved banksia),
B. cuneata (matchstick banksia),
B. goodii (Good's banksia),
B. oligantha (Wagin banksia),
B. tricuspis (pine banksia), and
B. verticillata (granite banksia).
Response to fire '' seedlings after fire,
Burma Road Nature Reserve, Western Australia '' seedlings and cone after fire,
Beacon Hill, New South Wales
Banksia plants are naturally adapted to the presence of regular
bushfires in the Australian landscape. About half of
Banksia species are killed by bushfire, but these regenerate quickly from seed, as fire also stimulates the opening of seed-bearing follicles and the germination of seed in the ground. The remaining species usually survive bushfire, either by resprouting from a woody base known as a
lignotuber or, more rarely,
epicormic buds protected by thick bark. In
Western Australia, banksias of the first group are known as 'seeders' and the second group as 'sprouters'. '' resprouting after fire, Burma Road Nature Reserve, Western Australia Infrequent bushfires at expected intervals pose no threat, and are in fact beneficial for regeneration of
banksia populations. However, too frequent bushfires can seriously reduce or even eliminate populations from certain areas, by killing seedlings and young plants before they reach fruiting age. Many fires near urban areas are caused by arson, and thus the frequency is often much higher than fires would have been prior to human habitation. Furthermore, residents who live in areas near bushland may pressure local councils to burn areas near homes more frequently, to reduce fuel-load in the bush and thus reduce ferocity of future fires. Unfortunately there are often discrepancies in agreed frequency between these groups and conservation groups.
Dieback Another threat to
Banksia is the
water mould Phytophthora cinnamomi, commonly known as "dieback". Dieback attacks the roots of plants, destroying the structure of the root tissues, "rotting" the root, and preventing the plant from absorbing water and nutrients.
Banksia's
proteoid roots, which help it to survive in low-nutrient soils, make it highly susceptible to this
disease. All Western Australian species are vulnerable, although most eastern species are fairly resistant. Vulnerable plants typically die within a few years of infection. In
southwest Western Australia, where dieback infestation is widespread, infested areas of
Banksia forest typically have less than 30% of the cover of uninfested areas. Plant deaths in such large proportions can have a profound influence on the makeup of plant communities. For example, in southwestern Australia
Banksia often occurs as an understorey to forests of
jarrah (
Eucalyptus marginata), another species highly vulnerable to dieback. Infestation kills both the jarrah overstorey and the original
Banksia understorey, and over time these may be replaced by a more open woodland consisting of an overstorey of the resistant marri (
Corymbia calophylla), and an understorey of the somewhat resistant
Banksia sessilis (parrot bush). A number of species of
Banksia are threatened by dieback. Nearly every known wild population of
B. brownii shows some signs of dieback infection, which could possibly wipe it out within years. Other vulnerable species include
B. cuneata, and
B. verticillata. Dieback is notoriously difficult to treat, although there has been some success with
phosphite and
phosphorous acid, which are currently used to inoculate wild
B. brownii populations. However this is not without potential problems as it alters the soil composition by adding
phosphorus. Some evidence suggests that phosphorous acid may inhibit proteoid root formation. Because dieback thrives in moist soil conditions, it can be a severe problem for banksias that are watered, such as in the cut flower industry and urban gardens. ==Uses==