Leaf damage survey
Leaf miners leave trails as they feed. The percentage of the leaf they eat can be measured. Photo: J Gollan © Australian Museum.
Leaf damage by invertebrate herbivores can be measured. Chewed leaves, leaf miner tunnels and gall abundances are all measurable signs of herbivore activity. The success of seedling growth is very dependent upon their exposure to these activities. Too much herbivory can lead to seedling death. By monitoring damage levels it is hoped we can deal with herbivore pressure before it is too late.
What you will need
- Pencils and data sheets for recording
- Herbivore2damage guide
Method
- Describe your site.
- Select a number of seedlings or juvenile trees at random. These should be trees that have simple, broad leaves (e.g. Eucalyptus spp.), as this method does not work for trees with needle like leaves such as River Oaks (Casuarina spp.) or more complex leaf shapes such as Fern-leafed wattles (some Acacia spp.).
- Select a number of leaves at random from each tree. Make sure the number of leaves is the same each time.
- Use the herbivore leaf damage key to assign each leaf a number. These numbered categories are based on the level of damage you estimate the leaf has suffered.
- When the method is repeated the results can be charted over time to detect trends in herbivore damage.
- Record your methodology. For example, how many trees and leaves per tree you chose.
