The Wet Tropics Management Authority manages the Yellow Crazy Ant Eradication Program (YCAEP).
The primary aim of the YCAEP, is to eradicate yellow crazy ant infestations in and adjacent to the World Heritage Area and to maintain the Areas' outstanding universal and heritage value.
It is anticipated the Program may take up to ten years to successfully eradicate yellow crazy ants from the area.
The YCAEP team in March 2017
From left: Karina Barnes, LJ Stockdale, Steven Brewer, Desiree Gowell, Peter Wieland, Scott Buchanan, Gareth Humphreys, Lucy Karger, Lesley Davis, Rhys Sharry, Kirsty Cantle, Chris Clerc, Mathilde Gordon
To ensure the Wet Tropics Management Authority achieves absolute eradication of yellow crazy ants from the Wet Tropics World Heritage Area and the Cairns region we follow these series of steps:
This baseline information tells us a critical story about yellow crazy ant habitat and diet preferences, dispersal capacity, life cycle, structural hierarchy, resilience level and nesting and foraging habits. Our scientific monitoring team work closely with James Cook University (JCU) researchers to acquire this information.
Once we have the YCA baseline story understood, the operations teams can head out to survey potential habitats, making visual observations, taking samples and using lures to coax YCA into view. At teach of these points, a GPS location waypoint is recorded for later mapping. These lures may also attract other ant species, which provides an idea of species diversity in the area. Surveys generally occur from October to May throughout the treatment area including the rainforest, creeks, sugarcane farms and residential areas.
Survey data from field GPS units are mapped up to reveal YCA presence/absences, the infestation boundary, YCA hot-spots and potential movement pathways, such as creek lines and dirt tracks used by machinery. This boundary lies 100m from the nearest recorded positive record.
Our dedicated monitoring team undertake regular quantitative luring surveys at over 60 survey sites across the Mt Peter, Bentley Park, Bayview Heights and Russet Park infestation areas. Surveys allow the program to determine changes in ant activity in relation to food preferences, seasonal climatic changes and the effect of bait on yellow crazy ant populations. James Cook University conducts scientific research on behalf of the Program to analyse the results of monitoring activities. James Cook University completes laboratory observations and experiments on live colonies of yellow crazy ants housed in a controlled facility of the Smithfield campus to gain a better understanding of their lifecycle.
Through approval from the Australian Pesticides and Veterinary Medicines Authority (APVMA), the Wet Tropics Management Authority is permitted to use Fipronil and S-Methoprene as insecticides to bait colonies within the infestation area. The Wet Tropics Management Authority is permitted under the Environment Protection and Biodiversity Conservation Act 1999 to bait infested areas three times per year mirroring the APVMA permit conditions.
Forested and agricultural areas are treated aerially by helicopter, with residential and riparian areas treated by hand by field staff to reduce the risk of bait entering waterways or sensitive areas.
During baiting activities, the uptake of bait is monitored by field staff to determine whether bait is being consumed by yellow crazy ants or non-target species. The active ingredients used are at a much lower concentration than commercial insecticides to reduce the risk of impacts to off-target species. Both active ingredients are not considered hazardous to humans or household pets, however they can affect some fish and aquatic organisms and should not be used in fishponds or streams.
Following on from baiting events, in areas where baiting has been sufficient and presumed successful in eradicating yellow crazy ants, post-treatment validation (PTV) is undertaken. PTV consists of fine scale luring on a 5x5m survey grid to ascertain absence of yellow crazy ants in the area. To avoid recording false positives, at least 10% of all lures will have a specimen collected, including any yellow crazy ants or look-alike ant species. After four consecutive post treatment validation surveys, at six monthly intervals, with no yellow crazy ant activity, an area can be declared eradicated. Currently three areas are under PTV, including a sugar cane farm in Edmonton, Wiseman West and Waterfall Close in Edmonton.
Despite the yellow crazy ant being one of the world’s worst invasive species, its biological attributes that contribute to its success means eradication from localised areas is achievable. While yellow crazy ants have the ability to rapidly attain high populations (most of which are sterile workers), range expansion occurs by individuals walking only a few metres (up to 100m) from the parent colony, rather than flying to new locations 2km away like many other ant species. This lack of a nuptial flight and a further lack of inter-colony aggression can result in the formation of super-colonies.
While the resulting super-colony is of great benefit to the success of the invader, its self-propagating dispersal method results in populations that are locally contained and easily mapped. Dispersal to new locations and throughout the wider landscape is only achieved by the inadvertent assistance by people. Providing that human mediated spread is prevented, an incursion of yellow crazy ants can persist in an area for a substantial period and be not much harder to eradicate than when it first arrived, though there may be a larger area that needs to be treated.
YCAEP Project Partners
The eradication of YCA would not be possible without the support of our many partners. These include:
The Australian Government
The Queensland Government
James Cook University
Cairns Regional Council
Yellow Crazy Ant Community Taskforce (Kuranda)
Conservation Volunteers Australia
Residents and Property Owners
Australian Department of Environment and Energy