This group of native plants are generally arboreal, attached to trees (some, such as sandalwood, are attached to plant roots). While they can produce their own energy, they also tap into the water and energy of the host tree they’re attached to.
They are hemiparasites, dependent on trees for their water, and they have an important place in the forest ecosystem.
In the Reserve
There are two species of mistletoe in the Reserve: Drooping (Amyema pendula) and Creeping (Muellerina eucalyptoides) Mistletoes.
Drooping mistletoe has been flowering for several weeks and is quite popular with birds, with fallen flowers dotting the ground in different locations. This species is found in south eastern Australia, extending into Queensland, and is mainly associated with eucalypts but also acacia. We find them attached to messmate and peppermint but have yet to see them associated with wattles.
This plant is the host for the larval stage of particular species of butterflies – the Imperial Jezebel, the Broad-margined Azure, Silky Azure and others. This mistletoe provides the specific habitat a range of butterflies need to live in. It has a long flowering period and is also an important source of nectar for birds (Watson, 2011).
Creeping mistletoe is not yet flowering but is putting on bright, glossy new growth. It is distributed over a smaller range, also in south eastern Australia, and flowers at a later time in summer. It is associated with eucalypts, in the main, as well as exotics. In the Reserve, we find them mainly attached to peppermints and less so with messmate.
This mistletoe, too, supports the larval stage of particular butterflies, among them the Black Jezebel (Watson, 2011). This butterfly can be seen later in the Reserve, in summer.
Role in the native ecosystem
In addition to supporting mistletoe- dependent birds and insects, mistletoes also provide fruit for birds and nectar for birds and insects, their highly nutritious leaves are eaten by possums and insects, and they provide nesting and roosting sites for mammals and birds. Other associations with mistletoe include an increase in the diversity of fungi beneath host trees. When mistletoe is present, there is a higher diversity of bird species. One study, for example, found there were significantly fewer woodland bird species in a site from which mistletoe had been deliberately removed compared to another where mistletoe had not been removed. The latter had a richer range of species.
A matter of balance
There has been a focus on the need to manage the parasitic mistletoe in Australia’s past, when mistletoe was declared a noxious weed. It has a reputation for colonising trees to the point the tree dies. This is particularly evident in the image of scattered gum trees bearing many mistletoes, in a paddock, in this article regarding mistletoe management. More recent understandings, however, point to the poor health and circumstances of those sole gum trees rather than the role of the mistletoes they carry.
The presence of mistletoe has some usefulness as an indicator of forest and tree health. The presence of mistletoe points to a healthy forest; too much mistletoe points to a forest under stress.
A great resource
Watson, D. M. (2011) Mistletoes of Southern Australia. CSIRO Publishing: Collingwood.