Twentieth Australasian Weeds Conference New and revised plant declarations in South Australia David A. Cooke, Michaela A. Heinson and John G. Virtue Biosecurity SA, GPO Box 1671, Adelaide, South Australia 5001, Australia ([email protected]) Summary South Australia has conducted a com- • Notification – The presence and locations of the prehensive review of plant declarations under the declared plant must be reported to the regional Natural Resources Management Act 2004. Various NRM Authority by the owner of the land. sections of this Act allow for prohibition of sale and • Control – Land owners are required to take action road transport of declared plants, legal requirements to destroy or control certain declared plant species for landholder control and formal notification of their present on their property. NRM Authorities are presence. Declarations are based on risk assessment also responsible for controlling these declared and policies adopted for each species. The review plants on road reserves, and may have the power has occurred over four phases with 155 weed policies to recover costs of control from the adjoining revised or newly developed. Policies cover broad goals landowners. and objectives, state risk assessment and regional The first comprehensive review of plants declared management actions. under weeds legislation in South Australia in 20 years, There are currently 140 declared plants in SA with as described in Heinson et al. (2014), commenced in another five currently under consideration. These are 2010. The review was split into phases and is now in alisma (Alisma lanceolatum With.), coastal tea-tree its fourth and final phase. For each phase a revised (Leptospermum laevigatum (Gaertn.) F.Muell.), dune or new, state-level policy was prepared for a plant. onionweed (Trachyandra divaricata (Jacq.) Kunth), Elements of the policy document include a succinct giant reed (Arundo donax L.) and parrot feather management plan with dot-points for outcome/s, (Myriophyllum aquaticum (Vell.) Verdc.). objective/s and implementation; a table consolidating Keywords Declaration, legislation, review. regional management actions based on a regional risk assessment (Virtue 2010); a declaration statement with INTRODUCTION sections of the NRM Act which apply; a state-level Declared plants are plants that are regulated under risk assessment; and synonymy. the Natural Resources Management Act 2004 due A ‘plant’ as declared under the Act may mean a to their weed threat to South Australia’s primary defined subset of a species, a whole species, two or industries, natural environments and/or public safety. more species or rarely a whole genus (Cooke 2016). The Minister for Sustainability, Environment and Its circumscription may be modified by the exclusion Conservation may declare a weed when some of the of particular cultivars assessed as having negligible powers of the Act are needed to implement one or more weed risk, or by restricting the declaration to ‘feral’ of the eight Natural Resources Management (NRM) individuals growing outside cultivation. Hybrids be- boards’ regional strategic plans to manage the weed. tween a declared plant and a non-declared plant fall Declaration provides a legislative tool to limit the outside the declaration. establishment and spread of a plant, thereby reducing This paper summarises changes to the schedule of future costs from its weed impacts and control costs. declared plants arising from the review. The schedule Plant species are declared under various sections of and policies for each declared plant are available on the the NRM Act relating to: Biosecurity South Australia website (www.pir.sa.gov. • Movement – The declared plant must not be moved au/biosecurity/weeds_and_pest_animals). on a public road (e.g. as a cutting, seed or potted specimen). Inadvertent movement of the plant on PLANTS REMAINING ON THE SCHEDULE animals, soil, vehicles, machinery or produce may New policies have been adopted for 104 plants also be prohibited. that remain declared on the schedule. However, the • Sale – The declared plant must not be sold at any specific declaration has changed for many plants. A outlet including nurseries, pet shops and market common change has been uniform declaration of a stalls. Sale of any animal, soil, vehicle, machinery species across NRM regions, removing anomalies or produce contaminated with the plant may also between local government areas. The plants which are be prohibited. declared as notifiable has been rationalised to those 313 Twentieth Australasian Weeds Conference that are not known to be or are rarely established in a and regional management programs no longer require region or the state. Some plants are now declared for enforced control. control by land owners in fewer regions, due to being Wild carrots had been declared solely to enable widespread and/or posing a lesser weed risk than other carrot seed producers to contract with the former plants. Animal and Plant Control Boards to control wildling carrots, a threat to the genetics of their crops, on public NEW PLANTS DECLARED roadsides. This practice is no longer necessary. Since the review commenced, 32 new species have been added to the schedule of declared plants (Table 1). PLANTS PROPOSED FOR DECLARATION This includes the twelve additional Weeds of National Five species are currently under consideration for Significance that were listed in 2012. declaration in Phase 4 of the review: The majority of newly declared plants are en- Alisma (Alisma lanceolatum) is an emergent vironmental weeds with impacts in terrestrial or water plant with large broad leaves and herbaceous freshwater natural ecosystems. Many of these were flowering stems from a short underwater rhizome. included in the Nursery and Garden Industry of South It can be mistaken for a native Alisma found in the Australia’s ‘Grow Me Instead’ booklet and hence there same areas that has been confused with the European was already widespread awareness of their invasive A. plantago-aquatica L. but may be an undescribed properties. Most newly added environmental weeds species (J. Conran, pers. comm). are not uniformly declared for control across the state, Coastal tea-tree (Leptospermum laevigatum) from with this being a decision of regional NRM boards. eastern Australia is an invader of near-coastal native For example, gazania (Gazania spp.) is declared for vegetation. Even in its native range it may behave as control in two of the eight NRM regions. Additions a seral species as habitats change, encroaching into to the list include non-indigenous Australian natives heath from neighbouring, stabilized, calcarenite dunes, such as bluebell creeper (Billardiera fusiformis and usually after a fire that temporarily raises the pH of B. heterophylla) and sweet pittosporum (Pittosporum acidic heathland soils (Burrell 1981). It was introduced undulatum). to South Australia as a native ornamental/amenity Only a few agricultural weeds have been added plant, and now makes incursions into various coastal to the list, reflecting the range of weed control meas- and near-coastal vegetation from plantings. Many of ures available in farming systems to minimise weed the public consider coastal tea-tree to be a native of impacts. These include the crop weed blue mustard SA, and it can be confused with native Myrtaceae (Chorispora tenella) and the pasture weeds apple of such as Leptospermum coriaceum (F.Muell.) Cheel Sodom (Solanum linnaeanum) and spiny rush (Juncus (green tea-tree). acutus). Buffel grass (Cenchrus ciliaris and C. pen- Dune onionweed (Trachyandra divaricata) is a nisetiformis), despite being a widely grown fodder sandbinding perennial of coastal front dunes, intro- plant in northern Australia, is now declared in South duced to Australia from southern Africa. It spreads by Australia due to the unacceptable biodiversity and fire seed when dry plants break off and are rolled along risk it poses. Most of the newly declared plants were beaches by the wind. It can be toxic to livestock by initially proposed by regional NRM boards following causing photosensitisation (Huxtable et al. 1987). regional risk assessments and consultation. Giant reed (Arundo donax) is a large perennial grass growing on stream edges and wetlands, native PLANTS NO LONGER DECLARED to a wide region of Eurasia. It resembles the common Ten plants have been removed from the schedule of reed Phragmites australis (Cav.) Trin. ex Steud. but declared plants during the review (Table 2). is a larger plant. Giant reed is sterile but vegetative Nine of the plants now removed from declaration dispersal mainly occurs when stem or rhizome frag- were declared in the 19th or 20th centuries due to ments are moved during flood events. It is a potential concerns about their impact on agricultural or pastoral invader in the southern parts of South Australia as it lands. However, changing farming systems and weed tolerates a wide range of conditions and climates with control methods have meant that such species pose moderate to high annual rainfall. Nonetheless, the draft less weed risks. The routine use of Group B herbicides policy recognises its potential for biofuel production enables ready control of soursob (Oxalis pes-caprae), and proposes measure to manage this risk in produc- small-fruited pheasants eye (Adonis microcarpa) and tion systems (Virtue et al. 2010). onion weed (Asphodelus fistulosus). Three thistle Parrot feather (Myriophyllum aquaticum) is a species have been removed from declaration (Table submerged