Future Directions: Alligator-Weed Research and Management. Shon Schooler CSIRO Entomology Shon.Schooler@csiro.au. Goal: To identify key questions and develop research projects that will increase our understanding of alligator-weed and lead to more effective management strategies. .
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Research and Management
To identify key questions and develop research projects that will increase our understanding of alligator-weed and lead to more effective management strategies.
Effect of herbicide, repeated leaf removal, and single event complete above ground biomass removal on the production, nutrient, and stored energy allocation of alligator weed (Alternanthera philoxeroides)
Alice Yeates, John Wilson, Mic Julien, Shon Schooler, and Leanne Hughes
440 plants over 5 weeks
1) Stems clipped (once)
2) Herbicide (Glyphosate 360g/L )
3) Defoliation (weekly)
Treatments and Biomass
Treatment Effect: Total Cumulative Biomass
Treatment Effect: Shoots vs. Roots
Stems and Leaves
NSW Agriculture Weeds Research Unit
Port Stephen Shire Council
Research Topic #1: Feeding damage of biocontrol agents.
How do different types of herbivory affect plant growth?
Can the strategic removal of small amounts of tissue have the same impact as general defoliation (ie. tip destruction vs. leaf removal)?
Does node damage effect root growth at the node?
Research Topic #2: Plant spread via nodes.
Do habitat conditions affect fragmentation?
What is the fate of fragments/nodes ?
How long can they (and what fraction) can survive adverse conditions (temperature, desiccation, submergence, etc…)?
Research Topic #3: The root bank.
It has been observed that flooding can trigger a flush of growth that has been mistaken for seedlings.
Greenhouse observations have found that roots can be completely dry for several weeks and then sprout after they are re-hydrated.
What is the fate of roots under adverse conditions?
Research Topic #4:Herbivory and disturbance mediating competitive outcomes.
When conditions are favourable (water present and herbivores absent) alligator weed can colonize large areas very quickly. However, with decreasing moisture and increasing herbivory alligator weed begins to loose ground and above-ground material eventually disappears.
How do flooding and herbivory interact to influence the competitive ability of alligator weed?
When is population growth reduced to zero?
Research Topic #5: Climate matching for new agents.
One goal of this project is to release agents that will control alligator-weed in cooler climates.
Can we predict the effectiveness of potential agents using
using CLIMEX and GIS models?
This is particularly relevant because the terrestrial herbivores (the second goal) will be more affected by climatic conditions.
Building models of plant population dynamics
What factor or combination of factors will lead to a decline in alligator-weed biomass?