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What is a weed?

A weed is a plant growing where it is not wanted, weeds in agriculture and those that invade bushland are difficult and costly to control.

In 2017 a Regional Strategic Weed Management Plan 2017-2022 (1.28mB PDF) was released for the North Coast Region (the Plan). The Plan was prepared in accordance with the Biosecurity Act 2015 which repeals the Noxious Weeds Act 1993. It outlines strategies and actions to achieve the goal of shared responsibility for weed management across all tenures. It will achieve this through a range of regulatory tools and a General Biosecurity Duty, more information is available from, Tweed Shire's weed control authority, Rous County Council website (see RH box for link).

Click here (161kB PDF) to view a list of weeds that have been identified by Rous County Council as high priority biosecurity risk species in the Plan for the Far North Coast region. A second document listed in the box also lists:
Many of the species listed in these documents are garden escapees and residents of the Shire can assist in the maintenance of healthy bushland and in reducing the cost of controlling inappropriate species through the choices that they make in their own gardens. To assist residents’, publications such as the Bushland Friendly Nursery Scheme: Environmental weeds and native alternatives and My Local Native Garden are available through Council’s Natural Resource Management Unit.

An example - Bitou Bush National Northern Containment Zone Project

Bitou Bush - a Weed of National Significance

Bitou Bush is a highly invasive weed native to South Africa. It was introduced into NSW between 1946 and 1968 by the Soil Conservation Service and mining companies to 'rehabilitate' dunes and control erosion on sand mining sites. As the majority of the Tweed Shire's 37km of coastline was cleared of native vegetation for sand mining, Bitou Bush and other introduced species like Horsetail She-oak and Coast Teatree were extensively planted along the Tweed's coastal dunes. In 2003, Bitou Bush was estimated to occur on 97% of the Tweed's coastline.

Legislative obligations

Under the Regional Strategic Weed Management Plan 2017-2022 a Biosecurity Zone has been established for Bitou Bush control along the entire Tweed coast and south to Cape Byron lighthouse and for 10 kilometres inland which requires all land holders to notify the local weed control authority (Rous County Council) of new infestations and to eradicate the weed if possible or destroy as much of the weed as is practicable and suppress the spread of any remaining weed.

What makes Bitou Bush such an effective weed?

A mature plant can produce up to 48 000 seeds per year. Studies have recorded between 2000 and 5000 seeds per square metre of soil underneath mature plants. Seeds are retained on plants for up to a year and are readily spread by foxes and birds. Although seed viability is generally low and is considerably reduced after two to four years, on the North Coast plants can mature and set seed within six months of germinating. This means ongoing control is vital. Bitou Bush is tolerant of shade, salt, wind, drought and low nutrient conditions and mature plants can resprout after fire, slashing and herbicide treatment.

How does Bitou Bush affect biodiversity?

Bitou Bush can form dense monocultures in disturbed areas but can also invade intact areas of vegetation. It reduces habitat and biodiversity values by outcompeting and replacing native plants and affecting the structure and composition of plant communities. Where medium and dense infestations of Bitou Bush occur, few other native plants are found. A reduction in native vegetation and a change in the structure of habitat also affect fauna species. There have been significant increases in the abundance of native bird species in areas where Bitou Bush has been controlled and replaced by native vegetation. In addition to an increase in the abundance of native bird species, there has also been an increase in 'habitat specialists' as there are many more food sources and habitat niches available. A monoculture of Bitou Bush favours 'habitat generalists', like the crow and pied currawong.

Many threatened plants and animals have also been adversely affected by Bitou Bush like the Scented Acronychia, Pink Nodding Orchid, Stinking Cryptocarya and the Glossy-black Cockatoo, Common Blossom Bat and Common Planigale. Within the NNCZ, control of Bitou Bush has seen a return of several threatened plant species, particularly the Pink Nodding Orchid.

The Bitou Bush National Northern Containment Zone (NNCZ) project

A long standing Bitou Bush control program in Queensland has successfully reduced approximately 700ha of Bitou Bush to scattered plants. The NNCZ compliments Queensland's achievements by moving the national distribution of Bitou Bush south from the Queensland - NSW border. The project has been undertaken in two stages. The first stage involved reducing the density and extent of Bitou Bush from the northern 10km of the Tweed coastline. This project was funded by the NSW Environmental Trust and the Northern Rivers Catchment Management Authority and was supported by Tweed Shire Council. Areas targeted included the Fingal Head Peninsula, Ukerebagh Island Nature Reserve and areas north of the Tweed River. The second stage of the project involves an expansion of the NNCZ project area to include the entire Tweed coastline and hinterland. This project is managed by the NRCMA through the Federal Government's Caring for our Country program. Whilst on-ground Bitou Bush control is being coordinated by the bush regeneration contractor Bushland Restoration Services, the project relies on considerable support and in-kind contribution from numerous project partners including Tweed Shire Council, Far North Coast Weeds, the Tweed Byron Local Aboriginal Land Council, Dune and Coast Care groups at Fingal Head, Kingscliff, Casuarina, Cabarita Beach, Hastings Point and Pottsville and the National Parks and Wildlife Service.

What has been achieved to date?

Between 2008 and 2011, extensive and ongoing control of Bitou Bush within the first stage of the NNCZ has resulted in significant reductions in the extent of Bitou Bush and density of Bitou Bush infestations. Monitoring has demonstrated that:
  • Heavy infestations have reduced in area from 13.8ha to just over 0.5ha;
  • Medium density infestations have reduced in area from 19.6ha to 2.8ha; and
  • Light infestations have more than halved, reducing in area from 183.3ha to 73ha.
While these achievements are considerable, a substantial and sustained effort is required to consolidate and expand upon these gains.

Comparison of Incidence of Bitou Bush 2008 - 2011 (1.4mB PDF)

Bitou Bush Photopoint Comparisons 2008 - 2011 (3.03mB PDF)

Works have continued on the NNCZ Project since 2011 with additional funding from State and Council allocated to both Tweed Shire and more recently Byron Shire where works will be funded until 2018. In addition annual aerial surveillance is undertaken in June to identify the effectiveness of the control methods and to target ongoing control.

For more information on the project, to join a Dunecare or Landcare group or to report sightings of Bitou Bush contact Council on (02) 6670 2400.

References

Tweed Shire Bitou Bush Control Strategy (James, R. & Wilson, C. 2003)
Bitou Bush National Northern Containment Zone Management Plan (James, R. 2009)
NSW Threat Abatement Plan Invasion of native plant communities by Chrysanthemoides monilifera (bitou bush and boneseed) (Department of Environment and Conservation 2006).

Last Updated: 08 August 2017