The Glenelg Ark project was established in 2005 under the Department of Sustainability and Environment Weeds and Pests on Public Land Initiative as a landscape scale fox control project. The project is a collaboration between DELWP and Parks Victoria and aims to facilitate the recovery of native mammal populations at risk from predation by foxes in far south-west Victoria by undertaking broad-scale and continuous fox baiting using buried Foxoff®.
By 2016 the program had expanded from its original 10,000 ha in 2005 to cover 90,000 ha of state forest and national park of which 70,000 ha is baited (Treatment Management Zones) and 20,000 ha not baited (Non Treatment Management Zones).
- Lower Glenelg National Park (south)
- Cobboboonee National Park
- Mount Clay State Forest
Non treatment control zones:
- Hotspur State Forest
- Annya State Forest
- Lower Glenelg National Park (north)
In 2011 the fox baiting program expanded to include Discovery Bay Coastal Park to reduce predation on a significant population of the Hooded Plover Thinornis rubricollis which is a beach nesting bird.
Glenelg Ark incorporates a comprehensive monitoring plan designed to evaluate the benefits of reducing populations of the Red Fox Vulpes vulpes to two native ground-dwelling mammal prey species Southern Brown Bandicoot Isoodon obesulus Long-nosed Potoroo Potorous tridactylus, and one arboreal species Common Brushtail Possum Trichosurus vulpecula.
There has been a significant decline in bait take from 2005 to 2013 in the Treatment Management Zones (TMZs), and a significant difference between TMZs and Non Treatment Management Zones (NTMZs) between 2005 and 2013. Overall, each of the three monitored native prey species has shown a significant positive response in site occupancy to fox control. However, factors that drive population change, i.e. colonization and persistence were not uniformly positive for all species or all TMZs.
The results of Glenelg Ark’s nine-year management project can demonstrate that the fox population can be reduced and maintained at relatively lower levels in fragmented landscapes, and that fox control has had a generally positive effect on the occurrence of the three native mammal species. Alternative hypotheses that could explain the observed variable response on TMZs are that resources may limit the population's capacity to persist in newly colonised sites, or that foxes have been replaced by feral cats as the introduced predator. These alternative explanations require further investigation to ensure the project is facilitating the recovery of small and medium sized mammals at risk.
To continually improve the management outcomes of the Glenelg Ark project over the next three years, a revised set of aims have been developed based on the results of the monitoring and evaluation of the project over the past nine years. These aims are to:
- Maintain the conservation gains achieved to date.
- Increase our understanding of the drivers for apparent recent decline in Southern Brown Bandicoots.
- Evaluate the possible broader conservation gains of the program. i.e. other species in the project area that are not currently monitored but are thought to benefit from fox control.
- Integrate risk-based fire planning and predator control actions for key response species into the program.
- Improve efficacy of predator control operations so that the project continues to be a best practice examples of integrated and landscape scale predator control.
2017 Update – from ARI Technical Report No. 275 (2016)
This report of monitoring activities between 2013 to 2015 was released by ARI in May 2017. The report provides new information on the fox control program and an assessment of monitoring techniques (hair-tubes vs digital cameras).
Hair-tubes vs digital cameras
It was found there was no overall significant difference in detection rates between cameras and hair-tubes; however, cameras are less costly to operate and are able to ‘capture’ a wider range of species in all weather conditions. The project will now use digital cameras for future monitoring.
Fox activity & feral cats
Studies found fox activity at locations with fox control was significantly lower compared with activity at locations without fox control.
There was no significant difference in Feral Cat activity between sites with and without fox control, although there are indications which suggest there could be instances where higher levels of Feral Cat activity may occur in treated areas.
Fox control response to selected native species
The project specifically monitors fox control response for Common Brushtail Possums, Southern Brown Bandicoots and Long-nosed Potoroos. The most recent report demonstrates how results can vary year to year.
In 2013 there was strong evidence of a positive effect on site occupancy from fox control on Common Brushtail Possums and Long-nosed Potoroos, and inconclusive evidence of a positive effect on Southern Brown Bandicoots.
In 2014 there was no evidence of an effect for Common Brushtail Possums, Southern Brown Bandicoots and Long-nosed Potoroos.
In 2015, it was found the number of sites occupied by Long-nosed Potoroos was greater at locations with fox control.
When taking a longer-term view between 2005 and 2015 sites occupied by Common Brushtail Possums remained higher in treatment locations compared with the number in non-treatment locations. Little change was observed for Long-nosed Potoroos and site occupancy of Southern Brown Bandicoots remained unchanged.
An important point is that native species site occupancy remains higher at locations with fox control than it was at locations with no fox control in 2005.
The limited response of bandicoots and potoroos may be due to a lack of suitable habitat for these species. Another factor to be considered is over the 10 years since the project began in 2005, there have been 7 years with below-average rainfall.
A number of recommendations are made in the report to improve outcomes of the Glenelg Ark project.
Robley, A., Moloney, P. and Neave G. (2016). Glenelg Ark— benefits to biodiversity from long-term fox control 2015 update. Arthur Rylah Institute for Environmental Research Technical Report Series No. 275. pdf. Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
David Pitts, 03 55 270 422, Glenelg Ark Project Officer, Far south-west, Barwon South West Region, DELWP.