Saturday, March 9, 2013 by
Valley flora being slowly choked by invasive plant
A biodiversity expert has expressed concern that the flora of Wied Babu in Żurrieq, a protected Natura 2000 site, is slowly being choked by an invasive plant from the Americas.
Alfred Baldacchino said the biodiversity at Wied Babu was “under great negative impact” by Cardiosperum grandiflorum, also known as Showy Balloon Vine or Love in a Puff.
The plant has already had a negative impact on carob trees, Mediterranean Heather and brambles at the mouth of the valley and “is rapidly advancing towards a healthy stand of protected buckthorn, destroying everything in its wake”, Mr Baldacchino said.
He pointed out that the plant was also spreading at the other end of the valley – one of the richest environments for Maltese indigenous flora.
The plant originates from the tropical regions of the Americas, especially Brazil and eastern Argentina, and has been introduced outside its native range as an ornamental garden plant.
However, Mr Baldacchino said its overall negative impacts were devastating. He believes it was originally imported as a garden plant and then it “either escaped accidentally or somebody dispersed its seeds intentionally”.
The seeds are dispersed by water and air and the plant forms dense infestations outcompeting indigenous vegetation. Its weight can also cause branches to break.
Such is the negative impact on indigenous species that it has been listed as a noxious weed in South Africa, Australia, the US and New Zealand, according to Mr Baldacchino.
Its invasiveness is so acute it has been added to the European and Mediterranean Plant Protection Organisation Alert list, he said.
Invasive alien species were spreading all over the world mainly because of transport and the ornamental garden industry, he pointed out, adding that some people claim the damage by these species was more acute than climate change.
A number of international conventions, such as the Convention on Biological Diversity and also the EU Environmental Acquis, tackle invasive species. The EU has an ad hoc committee that is studying the spread and drafting additional regulations for immediate control.
Malta is obliged to honour these provisions, which have been transposed into local legislation.
A number of publications such as the National Environment Policy and the Malta Environment and Planning Authority ‘s new guidelines for the management of invasive plants were published but no enforcement or monitoring was being done.
Mr Baldacchino said one of the measures was to stop the plant from expanding.
“This is not relatively difficult, though it needs manpower, and ongoing monitoring to uproot seedlings and established plants is urgently necessary,” he added.
Mr Baldacchino said he had received reports from the Flimkien Għal Ambjent Aħjar Tree Group that the vine was also spreading up the trees along Birkirkara’s Valley Road.
He informed the Environment Ministry and the planning authority, which said they were studying the matter.
The best form of management and control was prevention, which “unfortunately is completely absent”.
Where these plants have set root, Mr Baldacchino said, the best control method was to weed them before they seeded to reduce the dispersal.
Consistent follow-up was required for sustainable management.
“This is quite a heavy economical, social and ecological price that we have to bear following neglect and inadequate attention to prevent such alien species from establishing themselves,” he said.