Steve Irons (Swan, Liberal Party) Share this | Hansard source

I rise this evening to speak to the motion on World Wetlands Day 2010. I congratulate the member for Page for putting this motion forward and other members for their contributions to the debate. I spoke about World Wetlands Day during the last sitting week. I also spoke about the Canning Wetlands in my electorate of Swan. Yesterday I was down at the Canning Wetlands. I spent some of the morning clearing weeds with the Wilson Wetlands Action Group near the Wilson Lagoon which, unfortunately, looks like being overrun with Hydrocotyle, which is a weed ranked at about No. 57 on the noxious weeds list in Australia.

I was lucky enough to get down there a bit earlier than the action group. They have an elevated hide beside the lagoon. I was able to spend 15 minutes watching the birdlife down there, which is just fantastic. It was like watching National Geographic on pay television. It was a great experience and the peace was only broken by the state 20 kilometres seniors walking championship, which was not that noisy because there were only two competitors. I congratulate the winner; the other competitor had to drop out halfway through with an injury, so it was a fait accompli. Wilson Lagoon is a great area which gets a lot of community use.

Russell Gorton, who won the Canning Citizen of the Year award, was there with his mother. Two other volunteers, Rose and Ash, also attended to help clear weeds in the area. This volunteer group meet once a fortnight to eradicate weeds around the wetlands—there is no shortage of weeds. They are one of 17 volunteer groups in this area and are to be congratulated for all the work they do for the local ecology.

Back to the weed: I thank the Parliamentary Library for providing some additional information on this matter. The weed’s specific name is Hydrocotyle ranunculoides and it is native to the Americas. It has become more widespread in Europe as a result of being introduced as an aquarium and garden pond plant that became naturalised. To date it has only been found in the Perth region of Western Australia, principally in the Canning River. According to the government website Weeds in Australia:

This vigorous weed has the potential to spread to other waterways in other temperate regions. It is a potential weed of all freshwater environments, being an aggressive invader of marshes, wetlands, waterways and the edges of still and slow-moving water.

The Centre for Ecology and Hydrology in the United Kingdom has said that there are a number of varying methods used to control these weeds. Mechanical control is to cut with weed cutting buckets or bolts and remove the plant physically. A chemical control option is herbicides containing glyphosate, which can work well on this weed. The glyphosate products should be used through a low-volume apparatus to apply a low volume of concentrated herbicide to the leaf surface in order for any control to be achieved. There are also several methods of environmental control, but none gives a complete solution. Providing shading by planting trees assists as Hydrocotyle does not establish well in shaded areas. Providing shade in WA can be a challenge on its own because of our great lifestyle and plenty of sun.

Biological control options include a weevil called Listronotus elongatus, which has been demonstrated to feed exclusively on Hydrocotyle in Argentina. Following collection of the weevil on this plant, further work on this agent is planned in the UK. The adult weevil feeds on the leaves by scraping away the leaf surface and forming discrete holes, some of which become infected by unidentified pathogens. The adult females lay eggs in the base of the petiole and the larvae develop and burrow down into the stolon. Preliminary observations indicate that the larval damage is restricted to the stolon around the base of each petiole, possibly allowing other larvae to occupy neighbouring petiole or stolon sections. But we must make sure that this is a real solution and not go ahead with something that is going to cause damage to the local environment.

In conclusion, I thank the member for bringing the matter of World Wetlands Day before the House. However, the government must not just do the talking but also take action. The NRM group has had its funding cut by half since the Rudd government came in, which has seen a loss of employment and a loss of projects in the local wetlands area. So I urge the government to reinstate funding to the NRM. I also again congratulate all the volunteer groups who work in the Canning regional area.

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