Protecting Coastal Biodiversity
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.
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 (1.39mb)
Bitou Bush Photopoint Comparisons 2008 - 2011 (3.05mb)
For more information
For more information on the project, to join and dune or coast care 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).
Littoral Rainforest Remnants of the Tweed Coast
Littoral Rainforest is a closed forest community occurring close to the sea and dominated by rainforest plants. It is influenced by wind, salt and the harsh coastal environment. Littoral Rainforest contains a high diversity of plant species, including plants threatened with extinction like the stinking cryptocarya and scented acronychia. It also provides essential habitat for many native animals, particularly nectivorous and frugivorous birds and mammals.
Extensive clearing along Australia's east coast has severely reduced the extent of littoral rainforest and it is now listed as 'critically endangered' and protected under State and Federal environmental legislation.
Large areas of littoral rainforest along the Tweed Coast were lost between 1950 and 1970 as a result of sand mining. However small remnants remain at Fingal Head, Casuarina, Cabarita Beach, Pottsville and Wooyung. Tweed Shire Council, with funding from the Australian and NSW Governments under the Northern Rivers Catchment Management Authority’s “Engaging NSW Communities in coastline conservation” and "Caring for our Coasts" projects, is working to restore these remaining littoral rainforest remnants.
To find out more about littoral rainforest read the Littoral Rainforest Remnants of the Tweed Coast Factsheet (1.17mb)
Protection and Restoration of Pottsville Wetland
Pottsville Wetland is a large forested wetland to the west of Pottsville Waters and Black Rock residential estates. It is a State protected wetland, containing habitat for many plants and animals, including some that are threatened with extinction like the koala, glossy-black cockatoo and bush-stone curlew. The wetland also contains large areas of floodplain endangered ecological communities and threatened and rare plants. It occurs in the lower catchment area of Cudgera and Mooball Creek so the wetland's health is essential to protecting these coastal creeks.
Tweed Shire Council has secured funding from the NSW Government's Environmental Trust to protect and restore the Pottsville Wetland. The health of the wetland is threatened by urban and agricultural pollution, weed invasion, human disturbance, and predation of native fauna by domestic cats and dogs.
The project aims to protect the wetland from degradation and restore its conservation values. The project also aims to increase community awareness of the wetland's conservation significance and provide the community with skills and knowledge to assist in its protection.
To find out more about the project read the Protection and Restoration of Pottsville Wetland Factsheet (1.38mb)
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