Water-Way Weeds in the Spotlight on the Dumaresq River

19th March 2018

Two ornamental plants introduced to Australia a century ago have Northern Tablelands Local Land Services and Inverell Shire Council working hard to tackle these invasive species along the Dumaresq River.

Outlying patches spread from a large containment zone of Cat’s Claw Creeper and a recently discovered regrowth of Water Lettuce are the target for the renewed weed control projects, funded by NSW Catchment Action. The Cat’s Claw Creeper and Water Lettuce weed control projects are essential to preventing their spread downriver and into the Murray-Darling river system.

Northern Tablelands LLS Regional Weeds Officer, Jonathan Lawson, said they are targeting 21 new growth areas of Cat’s Claw Creeper with assistance from Inverell Shire Council weeds officers. Outcrops were formed after river-borne seeds dropped from the core infestation which covers the river frontage of several properties.

Cat’s Claw Creeper now extends along 170 kilometres of the Dumaresq River. Inverell Shire Council Environmental Compliance Coordinator Phil Sutton said it is critical to minimise infestation of this Weed of National Significance.

“It is a threat to riparian ecosystems, because it invades intact environments, creating an impenetrable canopy which collapses the native vegetation and prevents any germination in the understorey. Landholders need to take ownership of the program to assist in maintaining the containment lines that have been implemented and lessen the chance of regrowth,” Phil said.

Jonathan said Northern Tablelands Local Land Services and Inverell Shire Council had previously eradicated all known occurrences of Water Lettuce, but an orphan patch was recently discovered in a lagoon, or anabranch, of the Dumaresq River. Jonathan said they believe dormant seeds were uncovered by cattle movement, and a flood event triggered germination.

Water Lettuce is a purely aquatic species, carpeting waterways with capacity to impede water flow and adversely affect native ecosystems. A floating weed debris boom, successfully used in the past to capture the plant, has been installed across the lagoon mouth as a barrier to catch and quarantine the weed.

“We want landholders to know this is a regional priority weed which needs to be eradicated from the system. Free-floating weeds like these move downstream contaminating the Murray Darling Basin, so there’s a bigger picture at play”, Jonathan said.

Water Lettuce and Cat’s Claw Creeper are both included in the 2017-2022 Northern Tablelands Regional Strategic Weed Management Plan. For more information about the projects, or to report an occurrence of either weed, contact the Inverell Shire Council Weeds Officer on 02 6728 8288.

Media contact: Annabelle Monie on 0429 626 326 or annabelle.monie@lls.nsw.gov.au

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