The misunderstood magical mistletoes: ABC online article
Posted on 25 January, 2024 by Ivan
Connecting Country has a long history of raising awareness about the often misunderstood native mistletoe in our region and the benefits it provides to a large array of birds, insects and marsupials. Our bird walk for beginners along Forest Creek, Castlemaine VIC, highlights various patches of healthy eucalypt and acacia species that host the semi-parasitic mistletoe plant and provide a healthy ecosystem function for many of our woodland birds.
We recently came across a great article published on the ABC website, where Dr David Watson, a plant biologist from Charles Sturt University, is interviewed regarding the many benefits and misunderstandings regarding mistletoe and its importance for healthy ecosystems. Please enjoy the article below, courtesy of ABC Online.
Mistletoe plays a vital role in Australia’s ecosystem
Mention mistletoe and people think of the magical plant that inspires many on-screen kisses. Others might say it’s a parasitic weed that kills its host tree. Mistletoes are indeed parasites, but this humble little plant might be an unsung hero when it comes to attracting wildlife.
This is why ecologist Lee Harrison persuaded Melbourne City Council to plant 800 mistletoe seeds in perfectly healthy street trees around the inner city and CBD. “They punch well above their weight in the biodiversity stakes,” says David Watson, a plant biologist from Charles Sturt University. “They flower and fruit when most other stuff doesn’t, so they are often the only source of tucker for insects and animals during hard times. “Mistletoes are a bird beacon but they also provide for sugar gliders, koalas, possums and butterflies.”
There are around 1,500 different species of mistletoe in the world, and all 92 in Australia are endemic — found nowhere else in the world.”Most people don’t realise that the mistletoe we see in our trees here is native,” Dr Watson says. “Because we have that association with Christmas, people assume it’s an import, like blackberries and holly.”
Nuytsia floribunda, or WA Christmas tree, is actually a mistletoe. (Photo: Graeme Churchard).
Dr Watson is about halfway through a 25-year study based in native woodland around Albury, NSW. “Essentially, we removed naturally occurring mistletoe from every tree across half of our study sites and left them at the other half.”
Preliminary results were quite startling: the areas without mistletoe lost a third of their previous bird diversity. “It is one of the strongest described effects of what’s called a keystone species — one that has a disproportionate influence on the ecosystem,” Dr Watson says. Dr Watson believes mistletoe has the potential to turn “virtually useless” street tree species and cities into wildlife sanctuaries. And no, they rarely kill host trees but, if they do, it’s generally because the broader environment is out of whack. “They kill trees as often as fleas kill dogs,” Dr Watson says.
“Generally it’s only isolated paddock trees that succumb, and they are a symptom of a broader malaise — there are not enough trees in the area.” Mistletoes are semi-parasitic canopy-dwellers; they photosynthesise to produce their own food but rely upon their host for water and support. Dr Watson says the word “parasite” gives them a bad rap.
“Like any predator, they have a role to play in a healthy ecosystem.” Fire also plays a role in “cleansing” mistletoes to stop them taking over — many trees regenerate after fire but mistletoes don’t. Changes to burning regimes upsets this balance. Dr Watson is also researching the fact that mistletoes drop their leaves more than gum trees and those leaves contain more nutrients, so mistletoes feed the soil under the host tree and keep it moist. Importantly for wildlife, this leaf litter drives more microbes in the soil, more insects, and hence more food for birds.
Mistletoe are found in almost every type of Australian environment, except Tasmania.
Mistletoe fun facts
Mistletoe provides food and shelter for all sorts of bugs, animals and birds like the mistletoe bird.(Photo: Wikimedia Commons: Duncan McCaskill (CC by 3.0))
- Mistletoe are over 30 million years old and fossil records suggest they originate from the part of Australia that was attached to Gondwana.
- The Western Australian Christmas tree (Nuytsia floribunda), known for its stunning bright orange flowers, is possibly the largest parasite in the world. However, it’s suffered a 90 per cent decline over recent years.
- The WA Christmas tree has blades on its roots sharp enough to break skin and slice through underground cables! It uses these to tap into roots of any plant within 100 metres.
- Mistletoe can become vulnerable if their preferred host plant become more widely spaced. If there’s not be enough fruit to attract mistletoe birds, even a healthy plant cannot reproduce.
- The leaves of nearly every Victorian mistletoe are the preferred food of caterpillars of at least one type of butterfly within the Azures (Ogyrisspp) and the Jezebels (Deliasspp).
- Golden Mistletoe (Notothixossubaureus) grows only on another mistletoe, Dendropthoe vittelina, which in turn is parasitic on the relatively uncommon tree rough-barked apple (Angophora floribunda).
- As mistletoe seed germinates, it puts out a tendril that secretes a cocktail of enzymes onto the branch, making a hole the tendril grows into.
Fascinating, I have always loved mistletoe but now I understand it much better
thanks Gayle! wonderful to hear.