Weeds of national significance

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Vision

The extent and potential of African boxthorn in Australia will be well understood, stakeholders well equipped with information tools and knowledge, and strategic management will contain and reduce the weed’s impacts.

THE CHALLENGE

African boxthorn is a densely branched, perennial shrub growing typically 2-3m in height and with branches that end in sturdy thorns. The species originated in southern Africa and was introduced to Australia by the mid 1800s. It has readily adapted to a wide range of conditions including poor, shallow or rocky soils, salt laden winds, exposed locations and drought.
It can now be found in every state in Australia, in a broad range of climatic situations ranging from semi-arid inland to high rainfall coastal environments. It produces a fruit (berry) that is consumed by animals such as birds and foxes. Seed is spread in the landscape when excreted by animals. This is boxthorn’s primary means of spread.
African boxthorn is a weed of national significance due to its invasiveness, impacts, potential for spread and significant environmental and socioeconomic impacts.
Once introduced, it displaces native vegetation in both coastal and inland situations, reducing biodiversity values. It readily invades agricultural land, reducing access and usability. Boxthorn provides prime habitat for undesirable animals such as rabbits. It provides impenetrable barriers to farm animals, reducing access to pasture and water.
The fruit provides a breeding place for undesirable insects such as fruit fly, and a food source for birds and foxes, who in turn disperse the seed within the fruit. Being spread by animals including birds, African boxthorn is very challenging to contain and can readily spread to new areas including relatively remote coastal islands.

INTRODUCTION

The African Boxthorn Strategic Plan is necessarily broad in its scope. The Plan applies to African boxthorn (Lycium ferocissimum) throughout Australia, and the species is one of the most widespread weeds in the nation.

The Plan seeks to provide a broad and prioritised basis for national coordination of African boxthorn management to proceed. It does not set out to provide in-depth ecology and management information.
With African boxthorn being listed as a Weed of National Significance (WoNS), the Strategic Plan provides the initial step in implementing a nationally coordinated approach to managing the species. The Plan will direct national coordination through at least the first five years. This draft follows initial (early 2012) consultation on new WoNS with every state and territory government by Weeds of National Significance coordinators.
The African Boxthorn Strategic Plan sets out to provide strategic guidance as to where national coordination will best be applied to achieve improved national understanding of the species and its management, and a basis for strategic on-ground management results.

1.1.1Principles underpinning the strategy

The Australian Weeds Strategy (AWS) sets the national direction with relation to weeds. Weeds of National Significance (WoNS) form a component of AWS implementation.

WoNS strategic plans provide a basis for coordinated nationwide action on management of established weeds. The African Boxthorn Strategic Plan is important for all African boxthorn stakeholders throughout Australia. The Plan sets directions that when applied, will have implications for public and private land managers (particularly managers of nature conservation reserves and graziers), researchers and many other stakeholders dealing with African boxthorn.
State and territory jurisdictions have differing priorities and knowledge for the management of African boxthorn. State and territory weed strategies (or the equivalent) generally provide the basis for determining jurisdictional priorities. The African Boxthorn Strategic Plan has been developed following an initial consultation process that sought to promote jurisdictional involvement and ownership wherever possible.
Input from regional and local stakeholders has been sought wherever possible too. This input is critical as specifics regarding African boxthorn’s ecology and management differ significantly across its distribution. Being reflected in relevant regional and local strategies is an ideal means through which many Strategic Plan actions can be delivered. In implementing the Plan, the national coordinator will be communicating with regional and local weed managers and seeking integration of regional and local plan content and actions that reflect those in the Strategic Plan. Through this and similar mechanisms (such as provision of best practice management knowledge), improved effectiveness and efficiency of African boxthorn management on the ground will be achieved nationwide.

1.2The current situation

African boxthorn has been recorded in every state and territory in Australia. It has been declared under weed legislation in all jurisdictions with the exception of Western Australia. Boxthorn is established across most Australian jurisdictions, the Northern Territory being the exception (although African boxthorn has been recorded there in the past). Across its range boxthorn is in a very broad variety of situations, and has impacts on natural, production and other landscapes.

Consultation has revealed significant concern in numerous jurisdictions regarding the implications of ongoing spread of African boxthorn. On-ground action, particularly to protect natural assets such as island/coastal lands and threatened vegetation communities, has and is being carried out around southern Australia. To date, communication on this between jurisdictions seems to have been limited.
In all states (and the ACT), African boxthorn is a significant issue in inland situations where it is often widespread. In New South Wales, boxthorn is the most frequently cited widespread weed impacting on biodiversity. It is cited by 11 of the 13 NSW catchment management authorities (CMAs) for its threat to biodiversity in their regions. With the species being so widespread in NSW, asset protection (e.g. protection of threatened plant communities) in that state is likely to be a higher priority than prevention, eradication and containment.
Throughout southern Australia, African boxthorn is an invader of riparian and wetland areas. This includes areas listed under the Ramsar treaty and those considered nationally as High Conservation Value Aquatic Ecosystems.
In states including South Australia, Tasmania, and Western Australia boxthorn is of significant concern as an invader of offshore island and coastal vegetation (and impacts on seabird, seal and Australian sea lions habitat). Management work on offshore island infestations has been undertaken in each of these states.
Ironically though, African boxthorn can provide critical habitat for important fauna. In areas of coastal Victoria and South Australia it is providing an important habitat for the threatened orange-bellied parrot. At Low Head in Northern Tasmania boxthorn bushes provide protective habitat for a little penguin colony where native vegetation was removed long ago. In Western Australia west coast islands (e.g. Beagle and Abrolhos Islands), boxthorn provides habitat for Australian sea lions, particularly through the provision of shelter during pupping.
Primary limitations to further spread of African boxthorn appear to be in areas with an annual average rainfall of less than 200mm (e.g. the north of South Australia), and northern tropical climate areas (e.g. northern Queensland and Western Australia).
Best practice management of African boxthorn is complex due to the diverse range of habitats it is found in, ranging from semi-arid riparian lands to coastal islands. The often high conservation value flora and fauna found in these locations can be vulnerable to off-target damage if control measures undertaken are inappropriate for the habitat, or to local habitat loss that may arise with the removal of African boxthorn. Hence African boxthorn management needs to be tailored to specific situations.
A challenge for national coordination is the significantly differing jurisdictional priorities allocated to African boxthorn. For example, in South Australia the species is considered a high priority due to significant potential of spread into rangelands and other environments containing priority natural and production assets. However, in Victoria African boxthorn is considered to be so widespread and established that priorities are directed to less well established invasive species.

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