McLaren_D_Peri-Urban environments and weed invasion: issues, consequences and solutions

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Beyond the Edge: Australia's First National Peri-Urban Conference …

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

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  • 1. PERI-URBAN ENVIRONMENTS AND WEED INVASION: ISSUES, CONSEQUENCES AND SOLUTIONS. This is a placeholder image. To replace either right click and select “change picture” or insert a new picture via the insert menu and crop to Jackie David McLaren1,2, Greg Lefoe1, Tony Dugdale1, size. Steel1, Raelene Kwong1, Charles Grech1, John Weiss1, Fiona Ede1, Franz Images are1,available from: 1 and Trevor Hunt1. Mahr Daniel Clements or 1Department of Environment and 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 • • • • • • • • 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
  • 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Assessment • Majority of weeds – garden plants • System for declaration of weeds • Many weed species now voluntarily withdrawn from sale by the nursery industry or have been declared noxious.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
  • 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.
  • 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
  • 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