For more detail please refer to Sections 4.4 and 4.6 in the ACT Kangaroo Management Plan (PDF 6.8MB).
Eastern grey kangaroos have the potential to reach very high densities in suitable environments. Historically, concerns about an over abundance of kangaroos were related to competition for pasture with livestock, and this remains the case today. Kangaroos compete for water and damage fencing and fodder crops. Culling of kangaroos in rural areas for mitigating damage to farm assets, has been common practice for many years, and continues to be practiced throughout Australia today, including in the ACT.
More recently, significant concerns have been raised about the impacts of high densities of kangaroos and intense grazing pressure on threatened species and ecological communities.
Refer to Sections 3.4 to 3.11, and 5.2 in the ACT Kangaroo Management Plan (PDF 6.8MB).
Overgrazing can have a profound impact on ground cover, modify habitat that is critical for other species, and lead to soil erosion and a decline in water quality. The latter is of particular concern for drinking water catchments such as at Googong Foreshores. To successfully manage for conservation and water quality outcomes, kangaroo populations need to be maintained at a sustainable level.
Photo: Light and heavy grazing by kangaroos
Methods for specifically managing kangaroo population growth must be based on best available science, effectiveness, humaneness, cost-effectiveness, and safety. There are three categories of kangaroo control:
Culling involves removing a portion of the existing population by shooting; capture darting with an anaesthetic followed by lethal injection; or poisoning.
ACT Kangaroo Management Plan:
|Shooting: As the most humane and target specific technique currently available, shooting is the preferred technique for the reduction of kangaroo population densities in the ACT. Shooting of kangaroos to achieve land management objectives will be licensed subject to consideration of public safety, assessment of shooter competency, compliance with the Code of Practice for the Humane Destruction of Kangaroos in the ACT, and adherence to the defined culling season.|
|Capture Darting and Lethal Injection: Capture darting and lethal injection may be approved as a culling technique in the ACT, subject to compliance with relevant legislation and the Code of Practice for the Humane Destruction of Kangaroos in the ACT.|
|Poisoning: Poisoning will not be approved as a kangaroo culling technique in the ACT, unless humane, safe, target specific and environmentally benign techniques are developed.|
|Research: Research to develop humane alternatives to shooting will be encouraged, which are more suitable for urban and per-urban areas.|
The ACT Government has been investing in fertility control research for over ten years in partnership with the former Marsupial Cooperative Research Centre, the University of Newcastle and, more recently, with CSIRO and the Invasive Animals Co-operative Research Centre. The general aim of fertility control is to reduce population growth rates. Methods available include (a) sterilisation or (b) the delivery of a contraceptive or immunocontraceptive that controls fertility. Sterilisation is only practical on a small scale for captive populations due to the labour intensive and expensive process of capturing and surgically sterilising the animals. Even though there have been significant advances in fertility control methods for kangaroos involving contraceptives and immunocontraceptives in recent years, in the main, they are still in the research and development phase. There are also practical barriers to be resolved in relation to their widespread application for the control of free ranging populations. Like surgical sterilisation, drugs that inhibit fertility are currently only applicable to captive populations. Research and development of fertility control drugs is continuing. It is possible that, in the future, a fertility control drug could be developed that can be delivered in food to provide an effective, humane, non-lethal method for controlling free ranging kangaroo populations.
Photo: Fertility control research - eastern grey kangaroos being measured and vaccinated
ACT Kangaroo Management Plan:
Development of Fertility Control Methods: Cooperation between Parks and City Services and research institutions in the development of fertility control methods for controlling eastern grey kangaroo populations, especially immunocontraception (vaccines) will continue. This support may include:
|Advice to Land Managers: Advice and assistance will be provided to managers of ACT leasehold and National land on the use of fertility control to manage kangaroo populations on their land.|
The ACT Kangaroo Management Plan discusses three types of environmental modification as follows:
Of the above options, only vegetation manipulation is suggested as practical and it applies primarily to the valleys in Namadgi National Park and Googong Foreshores. Here, clearing has led to a considerable increase in native grass habitat suitable for kangaroos. Limiting water is considered to be ineffective in reducing suitable kangaroo habitat due to the fact that water is naturally available in the landscape anyway. The reintroduction of predators such as the dingo is not a socially acceptable option, although it is recognised that wild dogs in Namadgi National Park play an important role as the top predator in those ecosystems.
ACT Kangaroo Management Plan:
|Vegetation Manipulation: Vegetation manipulation to influence kangaroo densities will be considered in areas where this would support the management objectives for the land, especially where these objectives include the expansion of limited habitat and habitat for rare and threatened species.|
|Water Access: Limitation of access to water will not be undertaken by the ACT Government for managing kangaroo densities, as it is unlikely to be an effective technique.|
|Reintroduction of Dingoes/Wild Dogs: The reintroduction of dingoes/wild dogs will not be undertaken in lowland grassy ecosystems and rural areas of the ACT for the purposes of controlling kangaroo numbers.|
|Dingoes/Wild Dogs in Namadgi and Tidbinbilla: The dingo/wild dog population that is present in Namadgi National Park and Tidbinbilla Nature Reserve will be maintained as predators and a natural component of the kangaroo–pasture system.|
Refer to the ACT Kangaroo Management Plan (PDF 6.8MB) for more detail on the issues summarised above. The Plan contains references to hundreds of scientific publications underlying its policies and a helpful glossary of terms.