Monday, 24 July 2023
Mistletoe is a remarkable plant that essentially ‘supercharges’ the woodlands and forests where it occurs. It provides a perennial food source for many birds, mammals and insects through its foliage, flowers and fruits.
Another important biodiversity benefit of having healthy mistletoe on agricultural land and within our woodlands and forests is that it encourages a diversity of invertebrates that inhabit the humus-like leaf-litter beneath the clumps of mistletoe, providing food for a declining guild of birds: ground-foraging insectivores.
Through its unique structure, it also provides a great nesting site for birds; over 200 species of Australian birds have been recorded nesting in clumps of mistletoe. One of the most threatened of these is the Regent Honeyeater. During the breeding season, Regents both feed on mistletoe blossom and build their nests in the clumps. In recent years when blossoming of eucalypts has been poor, mistletoe has played a key role in the few successful nesting attempts by Regent Honeyeaters.
However, mistletoe does not fare very well during droughts, and it is killed when burnt in bushfires. In the past few years, we have seen dramatic declines and dying-off of mistletoes in many Regent Honeyeater breeding areas. Natural processes for mistletoe to return to these habitats (through birds such as the Mistletoebird and Painted Honeyeater and other generalist dispersers) takes a long time to occur. Hence BirdLife Australia has been developing some novel partnerships between First Nations groups, Local Land Services regions and arborists in key Regent Honeyeater breeding and foraging habitat to restore mistletoe that has been ravaged by wildfire and drought.
Here we report on a partnership project between BirdLife Australia and the Mindaribba Local Aboriginal Land Council (LALC), which aims to restore mistletoe on traditional lands ravaged by wildfires in Lower Hunter Valley of NSW. The Long-flowered Mistletoe Dendrophthoe vitellina on Mindaribba lands that have provided Regent Honeyeater nesting habitat were burnt in the 2016 and 2017 fire seasons, effectively destroying the mistletoe resource.
On these lands, we sought to expedite the recolonisation process by planting the mistletoe seeds ourselves, with the first plantings taking place in summer 2019–20. This novel work is a world-first in habitat restoration of this type and scale, with our project team now having planted over 4,500 mistletoe seeds onto Spotted Gum host trees in the Tomalpin Woodlands, near Kurri Kurri, on Wonnarua Country. Our current work is being assisted by the NSW Government through its Environmental Trust.
Previous monitoring of the summer 2021 planting achieved a survival rate of 13 per cent, which is consistent with or slightly higher than other experiments. Initial monitoring provided key learnings relating to seed placement on branches, orientation within the canopy, the size of the branch and consideration of the timing of bark being shed. We incorporated these learnings into our summer 2022 planting (funded by a Landcare Led Bushfire Recovery Grant) which was monitored in late June 2023. Excitingly, the survival rate for this planting was 20 per cent, 16–17 months after planting. We have now successfully established about 200 new mistletoe plants into this precious piece of habitat for the Regent Honeyeater.
Another important highpoint of the project was witnessing evidence of one of the original mistletoes our project team planted in December 2019 producing its first crop of fruit (in December 2022), proving that mistletoe restoration can provide a mature resource for woodland birds within three years of planting!
The process for planting mistletoe isn’t that difficult. We monitor the mistletoe clumps as they flower and then start to produce fruit. Once the fruit is ripe, it is ready for picking and we collect it from easily-accessed clumps. We try not to store the mistletoe for long — in fact, planting is best done on the same day as we pick them (if need be, they can be stored for a up to a couple of weeks in the fridge, but the seeds need to be picked with their stems attached to avoid them becoming over-ripe and mouldy).
We could plant the seeds low down as we walk around the forest, but that wouldn’t help Regent Honeyeaters, as they prefer clumps of mistletoe that are high in the trees, so we employ professional arborists to hoist the seeds up high into the canopy where the birds will use them. The seed is simply pushed out of the fruit-casing and wiped onto branches, preferably smaller lateral branches and on the underside (so that moisture from dew gathers and to keep it away from the prying eyes of mammals, like Brushtail Possums, that love to munch on mistletoe leaves). Then we wait and see how many mistletoe seeds sprout and grow!
It is still early days in this exciting work, and we are trialling different methods of collecting the fruit and planting the seeds to help us better understand how to do this most effectively.
We are extremely grateful to Mindaribba LALC for welcoming us onto their traditional lands on Wonnarua Country to work together on this exciting project and we pay our respects to their Elders, past, present, and emerging. BirdLife Australia recognises and is grateful for the immense contribution of Indigenous people to the knowledge and conservation of Australia’s birds.
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