Eradicate Newsletter: Issue 13 - Summer 2014
Japanese knotweed leaves and flower headsJapanese knotweed Fallopia japonica is a declared weed in Tasmania under the Weed Management Act 1999. The importation, sale and distribution of Japanese knotweed is prohibited in Tasmania.
Japanese knotweed is not well known in Tasmania but overseas it causes significant environmental, structural and financial damage, up to millions of dollars in some cases.
It is a fast growing, semi-woody perennial plant that forms dense leafy thickets up 5 m tall. Stems are stiff, hollow and bamboo-like, becoming tough, woody and speckled with age. Leaves measure up to 12 cm long and 10 cm wide, and have a pointed tip.
Japanese knotweed flowers from December to February. Flowers are small, white and occur on slender branched spikes. Fruit is a three-angled papery sheath that covers a single shiny black seed. Roots are coarse and grow up to 3 m deep and may spread many metres from the parent plant.
Japanese knotweed has been identified in the north at Launceston, Lilydale, Beauty Point and Scottsdale, and in the south at Dodges Ferry. Sites have been treated for several years with good results but work needs to continue. It is likely that there are infestations still to be discovered in Tasmania.
Japanese knotweed impacts
Japanese knotweed replaces other vegetation through shading and root competition. It dies back over winter, leaving bare soils open to erosion. The roots and rhizomes (underground stems) spread under walls, pavements and patios and can cause significant damage to roads and buildings.
Japanese knotweed can be eradicated in Tasmania and it is an eradication target in every municipality. Property managers are required by law to manage Japanese knotweed found on their land and the Invasive Species Branch can provide advice on how to do this.
Tasmania’s native and invasive predators will be mapped in a study that will use their scats (animal droppings) to find out where they live and what they eat.
A similar survey was under taken in 2008-2010 as part of fox monitoring activities but the 2014 survey will have a much broader focus and gather information about a wide range of animals, including introduced predators such as feral cats, dogs and foxes, and native predators such as Tasmanian devils and quolls.
Recent advances in technology will also add an additional element to the 2014 survey.
Using a new technique called Next Generation Sequencing, scat analysis will now also deliver information about each predator’s diet. This is a huge step and means that each scat is a real gold mine of ecological information.
The Predator Scat Survey will break new ground in mapping the distribution of native and introduced predators and their prey across eastern Tasmania.
The survey will help improve understanding of changes in Tasmania’s ecosystems, including the impact of declines in Tasmania’s native predators, such as the Tasmanian devil and eastern quoll, and related changes in invasive predator numbers, such as feral cats. This will provide a powerful tool for informing decisions in the management of wildlife conservation and invasive species programs.
The survey will also be trialling a new field DNA swab test that has the potential for rapid identification of fox scats, which would provide an invaluable tool for early detection of incursions.
The Predator Scat Survey will be under taken between March and June 2014 and is being supported by the Invasive Animals CRC, the Tasmanian Museum and Art Gallery and the Queen Victoria Museum and Art Gallery.
In this forum we address your questions about invasive species management in Tasmania.
Q: Are there any problems that come from feeding wild birds?
A: Wild birds are sometimes fed by people who have the best intentions but this can lead to some serious problems for our native birds, other people and the environment. Some of these are:
It is much better to feed birds naturally by providing suitable nectar-producing and insect- attracting native plants in your garden.
- encourages invasive birds
- nutritional problems from wrong food types
- obesity from overfeeding
- facilitates spread of disease
- creates imbalanced populations and may exclude native species
Q. What is an incursion?
A. The introduction of a species into an area in which they do not currently occur. Often used to describe the recent introduction of exotic and pest animals or plants into places where they are not wanted.
Horsetail with stobiliLandholders in southern Tasmania have recently come across a very ancient but highly invasive plant: horsetails, the common name for the genus Equisetum.
This is a family of about thirty primitive, non-flowering, perennial species from the Northern Hemisphere. Horsetails have a distinctive appearance with hollow, tail-like jointed stems with small simple leaves arranged in sheathing whorls.
Scouring rush Equisetum hyemale is a non-woody, non-flowering, erect perennial that can grow to 1.2 m. Stems are hollow, unbranched and jointed with remnant leaf sheath nodes. The stems are heavily grooved and are easily snapped off. Spores are produced in a strobilus, a small cone-like fertile structure at the tips of the stems.
Horsetails are ancient plants which reproduce via spores and tuber-bearing underground runners called rhizomes. Most horsetails infestations are the result of deliberate planting but they can rapidly take over large areas of garden or bushland. This happens from rhizome spread, rather than from spores. Horsetails are difficult to control as the stems are covered with a waxy cuticle and this means herbicides are not always effective.
Horsetails are also toxic to a range of animals including horses, cattle and sheep.
There are less than ten records of horsetails in Tasmania but they are on the National Environmental Alert List and are a declared weed in Tasmania that requires eradication.
If you think you have seen this plant it is important to report it to your Regional Invasive Species Officer on 1300 368 550.
Weeds? Feral cats? Rainbow lorikeets? Foxes? Deer?
Groups from government, industry and the environment met late last year in an open forum to discuss Tasmania’s worst invasive animals and plants, and how to collaborate in managing their impacts. So was there agreement on what was Tasmania’s biggest invasive threat?
The short answer is no and the long answer includes a long list of invasive animals and weeds that pose widespread threats to Tasmania.
While there may have been disagreement on what tops the list, there was solid agreement that stakeholders and members of the community all need to be working together to be most effective in managing all these threats.
The Invasive Species Community Partnership meets twice a year and brings together groups including the Tasmanian Conservation Trust, Environment Tasmania, the Natural Resource Management regions, BirdLife Tasmania and the Tasmanian Farmers and Graziers Association to discuss issues in an open forum. It is one way that the Tasmanian Government is facilitating greater community involvement in invasive species management.
A community attitudes survey carried out by Myriad Research in 2012 ranked feral cats as Tasmania’s worst invasive species, closely followed by foxes, rabbits and weeds.
Do you agree? What do you think is the worst invasive species in Tasmania?
During February vote for Tasmania’s worst invasive species on the Tasmanian Invasive Species Facebook page.
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Contact: Invasive Species EnquiriesInvasive Species Branch
171 Westbury Road
PROSPECT TAS 7250
Phone: 03 6777 2200
Fax: 03 6336 5453