Invasion of Native Plant Communities by Chrysanthemoides monilifera was listed as a KEY THREATENING PROCESS on Schedule 3 of the Threatened Species Conservation Act 1995 [12 March 1999].
Two subspecies of the South African shrub Chrysanthemoides monilifera are invasive in Australia and more specifically New South Wales, where they invade and displace native plant communities. Boneseed (subspecies monilifera) is the less important of the two weeds in New South Wales but it has the potential to be a serious threat to inland areas in the future if it is left uncontrolled. Bitou bush was first recorded in New South Wales in 1908 near Newcastle, , and between 1946 and 1968 was planted for dune stabilisation at a number of locations along the New South Wales coastline. It has spread rapidly from these plantings and is now found along 80% of the coastline, covering more than 900 km.
The invasive nature of both subspecies of Chrysanthemoides monilifera led to their listing as a Weed of National Significance by the Australian Government and declaration as a Noxious Weed in New South Wales.
Following its listing as a KTP under the TSC Act, the Department of Environment and Conservation has prepared a draft Threat Abatement Plan for NSW (Bitou TAP). A final Bitou TAP is due for release in early 2006. The Bitou TAP establishes priorities for bitou bush and boneseed control for the conservation of biodiversity across all land tenures. In particular, the plan identifies which native species are at greatest risk from bitou bush and boneseed invasion and the sites at which control is most critical. The Bitou TAP identifies 153 species, two populations and 24 ecological communities at risk from invasion by bitou bush and boneseed in New South Wales, spanning over 600 sites along the coastline. A priority list of 20 species, two populations and nine ecological communities has been identified. Using this list of priority biodiversity, approximately 60 sites have been identified as critical for the control of bitou bush and boneseed.
Undertaking bitou bush and boneseed control across all land tenures at these priority sites is the central action of the plan. In addition, the plan establishes monitoring programs to measure the response of priority biodiversity to bitou bush control. These monitoring programs are fundamental to managing threatened species more effectively and reducing the impacts of weeds to biodiversity more generally. Other core actions in the plan are to use best practice management, education and involve the community and fill the knowledge gaps identified.
The Bitou TAP identifies the following native species as being most at risk from bitou bush invasions: Plectranthus cremnus, Zieria prostrata, Gleichenia mendellii, Acianthus exiguus, Calystegia soldanella, Chamaecrista maritima, Ischaeum triticeum, Lepturus repens, Pultenea maritima, Vigna marina, Actites megalocarpa, Poa poiformis, Fontainea oraria, Diuris praecox, Sophora tomentose, Chamaesyce psammogeton, Senecio spathulatus, Stackhousia spathulata, Westringia fruticosa, Wilsonia backhousei. , The endangered populations most at risk from bitou bush invasions are: Glycine cladestina (broad leaf form) and Zieria smithii (low growing form). The ecological communities most at risk are: Eastern Suburbs Banksia Scrub, Littoral Rainforest (including Sutherland Shire Littoral Rainforest), Kurnell Dune Forest, Coastal Banksia Woodlands (predominately comprising Banksia integrifolia), Grassy Headlands (predominately comprising Themeda triandra), Eastern Suburbs Banksia Scrub equivalent communities (i.e. Coastal Sand Wallum Heath), Frontal Dune Vegetation Complex, Coastal Sand Dune complex (predominately comprising Acacia longifolia var. sophorae), and Dune Grasslands (predominately comprising Spinifex hirsutus).