Beyond the Edge: Australia's First National Peri-Urban Conference La Trobe University Oct 2013

1. PERI-URBAN ENVIRONMENTS AND
WEED INVASION: ISSUES,
CONSEQUENCES AND SOLUTIONS.
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David McLaren1,2, Greg Lefoe1, Tony Dugdale1, size. Steel1,
Raelene Kwong1, Charles Grech1, John Weiss1, Fiona Ede1, Franz
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Mahr Daniel Clements
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1Department of Environment and
http://imagelibrary.dpi.vic.gov.au/ Primary Industries
2La
Trobe University

2. Weed Impacts
• Weeds cost Australia $3.5-4.5 Billion annually
• Environmental costs – similar magnitude
• A new weed introduction can threaten
produce exports and cost $millions in control
and eradication costs
• Peri-urban communities are the interface
between urban and rural landscapes

3. Peri-urban weed Issues
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Land speculation
Land value
Lack of weed awareness
Weed management restrictions
Fire
Weed sources – purchasing weeds
Machinery and soil movement
Animals and fodder movement

4. The Weed Invasion Curve

5. PREVENTION

6. Solution - Weed Risk Assessment
• Majority of weeds – garden plants
• System for declaration of weeds
• Many weed species now voluntarily withdrawn
from sale by the nursery industry or have been
declared noxious.
Arum lily
Privets
Pampas grass

7. ERADICATION

8. Alligator weed – Weed of National
Significance
• Found in peri-urban
gardens being grown as
garden vegetable by Sri
Lancan community.
• Publicity campaign
• Over 800 infestations
treated
• Land ownership/transfer

9. Solutions
• Brushoff appeared to kill
plants but resulted in
fragmentation - alive
• Mixture of glyphosate and
brushoff was effective.
• Now have successful tools
for eradication.
• Using UAV have been able to
successfully map Alligator
weed infestations.

10. CONTAINMENT

11. Containment – Serrated Tussock
• 4 ha in peri-urban suburb
of Broadmeadows in 1954

12. Containment – Serrated Tussock
• 4 ha in peri-urban suburb
of Broadmeadows in 1954
• 30,000 ha by 1980

13. Containment – Serrated Tussock
• 4 ha in peri-urban suburb
of Broadmeadows in 1954
• 30,000 ha by 1980
• 130,000 ha by 1996

14. Victorian Serrated Tussock Working
Party
• Community lead strategy
• Developed in collaboration with DEPI and
facilitated large community serrated tussock
control grants and extension
• Worked in collaboration with Shires and
Councils who implemented rate rebate
schemes for weed management including
serrated tussock.

15. Solutions – Victorian Serrated Tussock
Working Party
• Comprehensive
enforcement program
• Grazing and pastures
• Herbicides
• Biological control
• Modelling Workshops
Web sites
Management
• Fire risk
guides
• Extension Papers
Media

16. Containment – Serrated Tussock
Working Party
• 45,000 ha now under
long term control

17. ASSET BASED PROTECTION

18. Western Grassland Reserve
• Less than 0.5% of
“pristine” basalt
plains grasslands
remain.
• Offset for peri-urban
growth expansion
around Melbourne

19. Western Grassland Reserve
• Adaptive weed management
• Herbicide impacts on native
species
• Weed eradication trials

20. Biological Control
• Uses natural enemies of the weed such as
insects, mites or fungi from the weeds
country of origin.
• Sustainable as biological control agents
breed and maintain populations and attack
the weed year after year.
• Every $1 spent on biological control has
returned $23 to the Australian community

21. Biological control of Gorse
• Gorse is a serious weed in the periurban localities of Wallan and
Kilmore north of Melbourne.
• Community and Government cooperation
• Equine landcare group – link for
Wallan/Kilmore.

22. Conclusions
Issues
• Time poor
• Many absentee landowners
• Land fragmentation
Solutions
• Weed Research
• Contractors
• Share farming
• Community engagement and empowerment
• Biological control