Invasive Species Discussion Paper
Invasive Species Discussion Paper
‘Ngootyoong Gunditj, Ngootyoong Mara’
South West Management Plan
(download a PDF from the Resources page)
Weeds and pest animals have become widespread across both public and private land throughout Australia. While some of these invasive species have had little impact, a number threaten the viability of native species by degrading and replacing native vegetation and communities, preventing the regeneration of habitat, disturbing soil and promoting erosion and, in the case of introduced predators, preying on vulnerable native animals. The impacts of some species have the potential to substantially increase in fire affected areas and with predicted climate change.
This discussion paper considers the current arrangements and legislative provisions for managing invasive species and presents future directions and raises a number of questions regarding the management of invasive species.
CURRENT LEGISLATION, POLICY AND MANAGEMENT
Park managers are required under the National Parks Act 1975 (Vic.) to exterminate or control exotic fauna and eradicate or control exotic flora in parks. Protected area managers are required under the Catchment and Land Protection Act 1994 (Vic.) to control certain species declared to be prescribed weeds or pest animals in Victoria.
The Department of Primary Industry’s Invasive Plant and Animal Policy Framework 2010 (IPAPF), provides the strategic directions for the management of existing and potential invasive species within the context of the Government’s Biosecurity Strategy for Victoria.
The framework takes a risk management approach to providing guidance for future policy, planning and community activity specific to invasive plants and animals in Victoria. There are four main goals to be achieved with the supporting elements of partnerships, engagement, monitoring and evaluation and research. These are:
- Prevention and preparedness
- Asset protection.
There is an emphasis on prevention and eradication as it is believed that this provides the greatest potential benefit for the least cost. For protected area managers, other priorities may be high risk weeds and pests that have a sufficiently low area of distribution as to be eradicable and programs addressing those species and locations where there is a high risk to significant values. The threats, risk and priority areas for the ‘Ngootyoong Gunditj Ngootyoong Mara’ South West Management Planning area have been identified through a scientific literature review undertaken by the University of Ballarat.
Many threatened species and communities are vulnerable to the impacts of invasive species. The Department of Sustainability and Environment (DSE) has implemented a web-based information system, Actions for Biodiversity Conservation (ABC), to help target resources to higher priority actions and accumulate knowledge about threatened species and communities. ABC helps track the progress of management actions in Action Statements prepared under the Flora and Fauna Guarantee Act 1988 (Vic.) and in Recovery Plans prepared under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.
A number of invasive species are listed as a potentially threatening process in accordance with Section 10 of the Flora and Fauna Guarantee Act. The DSE has published Guidelines and Procedures for Managing the Environmental Impacts of Weeds on Public Land in Victoria 2007. The Guidelines provide a decision-support system to enable public land managers to prioritise locations and resources for weed management.
The Glenelg Hopkins Catchment Management Authority (CMA) released a Regional Pest Animal Plan 2010 – 2014 which aims to:
- Prevent the introduction and establishment of new high risk invasive animals in the region.
- Reduce the impact of established invasive animals on key environmental, economic and social assets in accordance with the priorities of the Regional Catchment Strategy.
The Glenelg Hopkins CMA has also developed a Regional Weed Plan for 2008-2012 to:
- prevent the reintroduction and establishment of new weeds in the region, and
- reduce the impact of established weeds on key environmental, economic and social assets in accordance with the priorities of the Regional Catchment Strategy.
The Plan provides direction for all land managers in the catchment to aid them in meeting their duty of care in weed management. It recognises the legislative requirements of public land managers for biodiversity protection and encourages a tenure blind approach to weed management in the region.
Signs of Healthy Parks (SHP) is a Parks Victoria initiative seeking to build a comprehensive picture of the condition of our park network through monitoring threats, processes and natural values. Specific aims of the initiative are to:
- Establish an integrated framework and set of indicators to assess trends in the condition of natural values and threats in parks
- Systematically evaluate the effectiveness of management actions
- Provide early warning of emerging threats
- Provide data to assist future management and decision making
Monitoring Protocols form an integral part of SHP by ensuring that data is gathered in appropriate and comparable methods across the state.
Parks Victoria uses a risk-based approach to target control programs in areas of highest value exposed to the greatest threat from invasive species. Parks Victoria also responds to concerns from park neighbours and supports the management of pest animals and plants through Good Neighbour projects, which acknowledge that these pests can move between public and private land and so require land managers to work together. Most control programs are designed to meet at least one of three objectives:
- Protect important natural, cultural and other values
- Reduce the risk of weeds expanding their distributions to new areas
- Prevent the spread of invasive species onto neighbouring public and private land.
To increase effectiveness and cost-efficiencies, in the planning area there are many partnerships across land tenure to deliver landscape scale projects including the Glenelg Ark project which aims to substantially reduce fox numbers across 100 000 ha of State forest and National Park in the far south-west of Victoria. With reduced levels of fox predation an increase in native wildlife populations is expected (DSE 2010). The Glenelg Eden is a pest plant initiative which aims to reduce the impact of weeds on environmental values and natural assets on public land throughout the Glenelg region. The project targets new and emerging weed infestations in State forest and National Parks, and will also undertake general weed control at a number of identified high value sites (DSE 2010).
INVASIVE PLANT SPECIES IN THE PLANNING AREA
This potentially large evergreen tree grows to between 25 – 50 metres in height in plantations for the softwood timber industry. This plant is highly invasive and is a major threat through the spread from plantations and former occupancy sites along the Glenelg River. Seed can be dispersed over considerable distances through wind or carried birds such as the Yellow-tailed Black-Cockatoo. As numerous trees within the planning area and significant areas of surrounding plantations approach seed bearing maturity, the problem is likely to increase. Pines will tolerate most soils and will grow amongst a wide range of vegetation.
This is a climbing plant with the potential to smother native vegetation as well as forming a thick mat of tubers below the surface of the ground. This plant is spread by birds feeding on the berries which contain 1 – 9 seeds per berry. Plant stems and leaves die back over summer and re-emerge late summer into autumn. The underground tubers remain viable all year around. Foxes and rabbits may also spread plants. Two forms of this plant occur in the planning area– Common bridal creeper and South West Cape bridal creeper with the latter being far more aggressive. Common bridal creeper can be treated biologically by introducing a rust fungus whereas South West Cape bridal creeper has a leathery leaf and is there is no known biological control at this stage.
An evergreen shrub or tree growing to approximately 4 – 14 metres in height. Pittosporum is a native species but not endemic to the planning area. This plant can grow in a wide range of habitats and is highly invasive. It also tolerates drought, frost and shade and is very adaptable. The plant produces berries around July and each berry has 20 – 30 sticky seeds and birds will spread these through ingestion or by sticking to feet and feathers. Plants are also spread by Brush tail possums and foxes. Pittosporum is spread throughout the planning area and larger plants are sometimes difficult to treat as plants can sometimes reshoot after being cut.
This is a large evergreen shrub and has the potential to spread very quickly in native vegetation. This plant may also have been spread by dumping of garden waste. Italian Buckthorn produces a berry over the warmer months and this is spread by birds and other animals. This is a particularly difficult plant to treat when it is large. Smaller plants are generally hand – pulled but these also have a lignotuber positioned at right angles under the surface which causes the stem to snap of leaving part of the root system intact. This plant is also grown in private gardens and it will tolerate drought, frost and exposed conditions.
An erect evergreen shrub growing to approximately 1 – 2 metres in height. Seeds germinate in both autumn and spring. When seed pods burst in the heat of spring and summer seeds can be ejected up to several metres. Seeds are highly poisonous. Cape broom is widely spread in the planning area both along road-side vegetation and within parks and reserves. Two other broom species that occur in the planning area are English broom and Flax leaf broom and the latter is invading coastal areas and appears to be extremely invasive.
Boneseed is a woody erect shrub to small tree which grows to approximately 3 metres in height and 2 metres in width. It has the ability to form dense infestations that may smother all other vegetation. The plant produces a berry like fruit which is spread by birds, foxes and other animals. Each plant can produce up to 50,000 seeds and the seed bank in the soil can be 800 – 2500 seeds per square metre. This plant is widespread throughout planning area.
Myrtle Leaf Milkwort
This plant is an erect spreading shrub growing to 3 – 4 metres tall. It is a highly invasive ornamental plant that has spread in coastal areas displacing native species. Milkwort will tolerate a wide range of soil and vegetation types and will tolerate frost, wind and salt laden winds. Initially plants can produce up to 2,000 seedlings per square metre. Competition reduces this to 12 – 30 per square metre after one year. Seeds are able to germinate in heavy shade and seedlings can scramble through vegetation until more favourable light conditions are met.
An evergreen and extremely thorny shrub growing to 5 metres tall. This plant is found mainly in coastal areas in the planning area and it will tolerate salt spray and drought. Boxthorn produces berries during summer and autumn and these are spread by birds and foxes. Plants are difficult to treat because of long spines along branches and they have the ability to sucker from root fragments if mechanically disturbed. Older plants have longer spines and are more resistant to grazing or browsing.
This is a prickly, scrambling perennial shrub that will form impenetrable thickets particularly along water courses. Blackberry tolerates sun, shade, frost, drought and fire. The plant is spread through birds, foxes and humans. Blackberry is widespread throughout the planning area and is usually controlled by applying chemical.
Other high priority invasive plants in the planning area include:
- Coast Wattle
- Asparagus Fern
- Bluebell Creeper
- Mirror Bush
- Pampass Grass
- Common Dipogon
- English Ivy
- Texas Needle-grass
- Toowoomba Canary-grass
- Harlequin Flower
INTRODUCED ANIMAL SPECIES IN THE PLANNING AREA
Foxes are an introduced predator that have spread across the southern two thirds of Australia and are implicated in the decline and extinction of a wide range of ground-dwelling mammals and birds which have not evolved to cope with this adaptable and efficient hunter. Species highly susceptible to predation include ground dwelling mammals, reptiles, and birds. Current control occurs through 1080 baiting across large landscape scale areas through the Glenelg Ark project.
Rabbits are widespread across the planning area. Populations are thought to be increasing in some areas. Myxomatosis introduced in the 1950’s had some effect on stabilising populations although it has been shown in the past that rabbits can build up resistance to viral strains of the disease and numbers will subsequently increase. RCD or calici virus did not have any noticeable effect on coastal populations. With large scale fox baiting programs this may also lead to an increase in rabbit populations in the future. Foxes can reduce the population of young rabbits by up to 80% and if fox control programs are to continue some thought may have to be given to increased rabbit control at the same time.
Feral cats are widespread throughout Victoria. They are opportunistic predators and will eat a wide variety of foods. Their diet at any time will usually consist of those species of prey most available to them. Dietary studies have shown that the rabbit is the major food item of feral cats in Victoria, but mice, smaller native mammals, reptiles, birds and invertebrates are also eaten. Population trends are largely unknown but are thought to be increasing. No large-scale control methods are available yet, and, in some areas they may have reached a state of equilibrium within their habitats.
Feral goats are a major environmental and agricultural pest that have a major effect on native vegetation through soil damage and overgrazing of native herbs, grasses, shrubs and trees, which can cause erosion and prevent regeneration. They foul waterholes, and can introduce weeds through seeds carried in their dung. Particularly during droughts, feral goats can compete with native animals and domestic stock for food, water and shelter. Populations are thought to be increasing in areas including the Mt Napier State Park and Lower Glenelg National Park. Populations tend to recover well from culling and, except on islands, eradication is usually impossible. To protect the environment, control is best focused on areas that contain threatened native plants, animals and communities. Competition and land degradation by feral goats is listed as a key threatening process under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. Under the EPBC Act, the Commonwealth in consultation with the states and territories has developed the Threat Abatement Plan for Competition and Land Degradation by Feral Goats.
Pigs will survive on a wide range of food and will consume anything from plant matter to carrion. It can also be assumed that they will feed on small native animals and birds but adequate data has not been gathered to date. Freshwater swamps and lakes in the planning area provide ideal habitat for pigs giving them shelter, food and water and once they become established it is difficult to deal with the problem.
Red and Fallow Deer
Deer are regularly sighted on Gunditjmara Traditional Owners properties (Lake Condah, Muldoons, Vaughns and Allambie) adjacent to Mt Eccles National Park potentially disturbing cultural heritage sites. Red deer are also regularly sighted along the northern boundary of Lower Glenelg National Park. They do not appear to enter dense native forest and prefer to remain near open breaks or pine plantations.
- Gunditjmara Traditional Owners aspirations for a skills audit and training/capacity building in all aspects of protected area management.
- Work with adjacent land owners and key stakeholders on landscape scale and integrated pest plant and animal programs.
- Adopt the DPI’s Invasive Plant and Animal Policy Framework in the planning area and the priorities detailed in the framework.
- Monitor the effectiveness of all weed and pest animal programs to assess their effectiveness in achieving objectives for both threat reduction and biodiversity conservation. Monitoring and evaluation should inform adaptive management and allow reporting and local and state-wide scales.
- Continue to undertake research to increase understanding of the extent and impact of high risk invasive species as well as measuring the effectiveness of management programs.
- Collect baseline data on occurrence and distribution of invasive weed species in area of high conservation priority.
- Continue to work cross land tenure with other agencies and protected area managers (including Catchment Management Authorities, DPI, DSE, community groups and park neighbours) in cooperative management and monitoring programs.
- Improve hygiene procedures and manage recreation and others uses of affected areas to contain the spread of pathogens.
- What values may be under increased pressure from pest plants and animals as a result of Climate Change?
- What are the natural and cultural values that are important and need protection from pest plant and animal threats?
- What specific pest species do you consider as priorities? Which values do they impact upon, and how?
- Are there new and emerging pests that need identifying? How can the community help land managers?
- What native species are impacting on natural values, and how should this be managed?
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Contact: James Hackel