Integrated pest management: NSW case studies
For more information on integrated pest management (IPM), see What is integrated pest management?
Case studies are available on:
Rabbits impact on:
threatened plant communities such as the Eastern Suburbs Banksia Scrub endangered ecological community at North Head
cultural heritage sites like the Quarantine Station at North Head
the amenity and recreational values of public open spaces, such as national parks, picnic areas, council parks, sports fields, golf courses and footpaths, and suburban gardens.
The control of rabbits is listed as a priority in the Sydney Region Pest Management Strategy, with control undertaken by the Office of Environment and Heritage (OEH), Cumberland Livestock Health and Pest Authority and other land management agencies including local councils.
A number of control methods are used to reduce the impacts from rabbits:
Chemical control: Pindone baiting is used where rabbit numbers (and impacts on park values) are high and population levels must be controlled. A daytime rabbit monitoring method based on observations of rabbit numbers, scats and signs is used to help agencies determine when populations warrant chemical control. Pindone can also be safely used to control rabbits in urban areas where 1080 baiting is not permissible. Chemical control is followed by strategic secondary controls.
Biological controls: The introduced virus myxomatosis is usually evident in rabbit populations in Sydney in summer and when prevalent can help keep rabbit numbers low. The Rabbit Haemorrhagic Disease Virus (RHDV) is a calicivirus also introduced to Australia. It is available to land management agencies as a virus on carrots and is released by OEH and other land management agencies in northern Sydney in late summer when conditions are most suited to the spread of the virus. Because rabbits can develop immunity to RHDV, rabbit populations are tested for their susceptibility to the virus before its release. Other control techniques can be implemented immediately after a biological control has had its effect on a rabbit population to take further advantage of the population decline.
Shooting: Ground shooting is undertaken in suitable open spaces to maintain a rabbit population at low numbers. It can be used to control small isolated populations or is used after poison baiting or biological controls have had an effect.
Harbour removal: In northern Sydney, rabbits rarely construct underground warrens but they do take advantage of dense weedy undergrowth often found at the edge of grassy open space. Weed removal programs are best undertaken after rabbit numbers have been lowered to make it difficult for remaining rabbits to flourish. Weed removal should not be undertaken when rabbit populations are booming because many rabbits will simply disperse and set up new populations in new areas.
1080 fox baiting sign at Moonee
Beach Nature Reserve.
In Kangaroo Valley, OEH is conducting a fox control program to protect the endangered brush-tailed rock-wallaby. This program involves combining chemical controls and other techniques, such as 1080 baiting, shooting and leg-hold trapping. Works are undertaken both in and away from OEH-owned land to ensure the best coverage of the area is achieved.
Baiting is conducted at over 60 bait stations. Most stations are permanently covered by poison baits. The other stations (private properties where landholders do not want permanent baiting) are baited for one week each month. The bait type used in the baiting program is varied to try to attract as many foxes as possible.
In addition to the baiting program, OEH contracts two sessions of fox shooting or trapping in the area each year. This is to assist in controlling bait-shy foxes and foxes on properties where landholders are not interested in fox baiting.
As part of the fox control program, fox abundance is also monitored twice a year using sand pads that record fox footprints to indicate whether fox numbers are decreasing.
OEH targets weed control methods to areas where bitou bush is having a negative impact on threatened species. In the north-east of Sydney, control is undertaken at Lion Island and Barrenjoey Headland. Both sites are listed as highest priority sites in the Bitou bush and boneseed threat abatement plan and are critical priorities in the Sydney North Region Pest Management Strategy. The biodiversity under threat from invasion by bitou bush is the Themeda Grasslands endangered ecological community.
Control is achieved using a combination of methods.
Chemical control methods
Aerial boom or spot spray by helicopter is undertaken in winter when native plants are semi-dormant and less susceptible to spray drift and bitou bush is growing and highly susceptible to low doses of herbicide. Another advantage of winter spraying is that bitou bush is flowering and can easily be seen from the air and distinguished from native plants. The herbicides glyphosate or metsulfuron-methyl are most commonly used. Aerial spraying allows access to large amounts of bitou bush in otherwise inaccessible areas like coastal headlands, sea cliffs and islands. Aerial spot spraying is very accurate; a good operator can target a single bitou bush without harming the native vegetation around it.
Ground spot spraying or foliar spraying is used where access is easier. Like aerial spraying, ground spot spraying takes place in winter when bitou bush is growing and native plants are less active. Ground spraying can be undertaken using a traditional low-pressure hand-held spray unit on the target plant foliage or a splatter gun which delivers large droplets of high concentration herbicide. With the splatter gun, only a small amount of solution is needed on each plant.
The cut and paint method is often used to control bitou bush. This method of applying herbicide, although time-consuming, poses no risk to surrounding native vegetation and can be used in sensitive areas where spraying is not appropriate, for example adjacent to the fishermen’s cottages at Barrenjoey or in areas where bitou bush is invading littoral rainforest.
Hand weeding is effectively used as a follow-up control to remove bitou bush seedlings before they grow too big and dominate the surrounding vegetation.
Biological control methods
Several biological controls have been trialled and released at Barrenjoey and some have spread across the water to Lion Island. Bitou seed fly, bitou tip moth and the bitou leaf roller moth all occur at Barrenjoey either through release or by having spread from other release sites. Tip moth and seed fly are now common across the distribution of bitou bush. School children can breed and release the bitou leaf roller moth as a class project through the Weed Warriors program.
Strategic control of bitou bush at Barrenjoey and Lion Island has seen a significant reduction of bitou bush and an improvement in the health, density and spread of themeda grasslands at these sites over recent years.
The National Parks and Wildlife Service has published a video of aerial bitou bush spraying in the Cape Byron Reserve area.
Page last updated: 10 May 2013