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No Palm, No Harm

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This is the call of wildlife carers along the east coast Australia who are regularly called out to rescue wildlife that has been injured or become entangled after feeding on Cocos Palms.

The Cocos or Queen Palm (Syagrus romanzoffiana) is native to Brazil in South America. Until the late 1990s this resilient, drought tolerant species was one of the most planted palms in Queensland and still features prominently in several historic (state heritage listed) sites including the City Botanic Gardens.

The Cocos Palm has become widely naturalised and can be found growing from Darwin to Hobart. This palm is now regarded as an environmental weed due to its ability to prolifically reproduce, creating thick carpets of seedlings that outcompete recruiting native species. It is commonly sited in urban bushland, riparian areas and dry eucalypt forests.

Like many Councils, Brisbane City Council has actively managed this palm’s weed potential by reducing the number of specimens on site to hold one representative collection only, and undertaking seed removal of these remaining trees.

While it is not a prohibited or restricted invasive plant under the Biosecurity Act 2014, it is a Class “R” under Council’s Brisbane Invasive Species Management Plan. This declaration encourages residents to actively reduce populations of this palm via complete removal.

One of the native animals most affected by the presence of Cocos Palms is the flying fox, often called fruit bat. Flying fox numbers have significantly decreased during the past 50 years; the Spectacled Flying Fox and the Grey-headed Flying Fox are now classified as ‘Vulnerable to Extinction’ on the Federal Government’s Threatened Species list.

Deadly Attraction

Ironically, by feeding on Cocos Palm fruit, flying fox populations are spreading the very seeds that are contributing to the mammal’s rapid decline. Flying foxes have the ability to cross-pollinate over great distances and carry fruit and seeds far away from parent trees. They can fly around 40 kilometres per hour and up to 50 kilometres each night.

Fruits occur in large clusters and consist of a hard nut surrounded with a thin layer of fibrous flesh that is orange and sticky when ripe. The fruit can be toxic for animals and the fibrous seeds can create gut obstruction or become wedged in the animal’s teeth, leading to a slow death by starvation.

Latest information shows that flying foxes are now suffering from the premature wearing of teeth due to availability of the hard seeds all year around.

Wildlife carers warn that the sound of noisy birds around a Cocos Palm could mean there is a flying fox trapped in the massive strappy fronds or it has its wing membranes damaged from the tough flower spikes.

Australia – lucky to have its flying pollinators

Australia is the only continent in which the dominant trees are pollinated largely by birds and mammals (some of which are highly mobile) as well as by insects. Australian plants invest very heavily in pollination compared with trees in Europe and North America, most of which are pollinated by wind.

Author Tim Low, talking about ‘Climate Change Myths’, points out that contrary to popular belief, many Australian plants won’t need to migrate in response to climate change. Fossil and genetic evidence suggests that eucalypts, banksias and many other woodland trees survive climate change in situ by producing genetically variable offspring, some of which prove well adapted to new climatic conditions.

This is made possible by very high investment in pollination, which sometimes occurs between different tree species, resulting in the rapid evolution of new eucalypts by hybridisation. Eucalypts hybridize on a scale unmatched by any other trees on earth.

“This palm is now regarded as an environmental weed due to its ability to prolifically reproduce, creating thick carpets of seedlings that outcompete recruiting native species.”

Flying Foxes:

  • Are very clean animals and constantly groom their fur and wing membrane.
  • Have a complex social system and spend their day in permanent tree-top communal camps.

Have more than 20 different calls for communication

  • Have old males guarding the boundaries of the camp keeping a look out for predators such as eagles and pythons.
  • Lyssavirus is not spread when flying foxes fly overhead or roost in trees; it can only be transmitted through deep tissue bites or scratches.

Gardening Australia television presenter Jerry Colby Williams says “our flying gardeners are a priceless environmental service that sustains our natural environment”. He urges gardeners to help save the species by getting rid of existing Cocos Palms or at least having the flowers cut off before they seed. “Any gardener who grows a Cocos Palm will be aware of how much seed they actually set – seed by the barrow load – and that’s the problem. They germinate wherever they fall.

“If you’re thinking of growing a feather palm, try growing a Bangalow, Foxtail or Norfolk palm instead. That way gardeners rooted to the earth can look after the flying gardeners as well,” he advises.

Top a Cocos

In bushland settings, individual palms can be destroyed by cutting the crown off below the lowest frond; it is not necessary to treat the stump with herbicide as it will not reshoot. In gardens and urban areas it is more visually appealing to remove the palm at ground level instead of leaving a stump.

For more info on Flying Foxes contact Bat Conservation and Rescue QLD – bats.org. au or WIRES Australian. Wildlife Rescue Organisation – http://wires.org.au

References

Low, T 1917, The New Nature: Winners and Losers in Wild Australia, New edition, CSIRO Publishing, Collingwood. Wild About Australia 2018, accessed 1 April 2019, www.wildaboutaustralia.com

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