[By STEVE HYNES, Warrnambool Standard: Thur 24 December 2009] The Department of Primary Industries (DPI) has developed a new high-tech model for weed surveillance to determine how and why weeds are spreading across Victoria. DPI pest management catchment co-ordinator Brett Madigan said pest management officers had tested a new biometric model to identify and map the potential spread of seeds from known weed sources.
"Surveillance activities have long been a key component in working out if and how weeds are spreading," Mr Madigan said.
"Traditional methods involve intensive inspections around each weed infestation, followed by additional surveys on all surrounding properties.
"The new biometric model incorporates five years of localised Bureau of Meteorology wind direction and speed data and takes into consideration the effect of daily rainfall greater than five millimetres.
The biometric model was tested in five locations where the Glenelg-Hopkins regionally prohibited weed species golden thistle had been found previously, covering an area of 1800 hectares.
Mr Madigan said the results showed the area infested by golden thistle was greater than originally thought but all newly identified infestations were contained to those properties where the weed had previously been found.
"This suggests landowners’ control work and the local topography both had a significant impact on stemming golden thistle’s spread," he said. Traditional surveillance methods carried out in the region earlier this year spanned 16 properties covering 2800 hectares.
Using the traditional weed surveillance technique, DPI officers found one new golden thistle infestation on an adjoining property.
This may not have been discovered through the biometric model because spread was most likely aided by an animal and not by wind dispersal.
Mr Madigan said early results had suggested the biometric model was more effective if the origin of an infestation was already known.
"The model can then highlight zones from where weeds are likely to spread, cutting down the inspection and the resources needed for this werk." he said.