What does it mean when our native animals are overabundant, impact causing or problematic?
Native animals, while dear to our hearts, are sometimes in conflict with humans when they compete for food, water, refuge and space. When this happens, the terms overabundant, impact causing or problematic may be used.
Find out more about what this means and how the issue is managed.
This article uses the more general terms ‘impact causing’ and ‘problematic’ when talking about native animal species that, for a range of reasons, may cause damage to the environment or property (including crops or built structures), or pose a safety risk or hazard to people or industry.
When are native species considered problematic?
Significant changes to native animal population numbers may result in impacts, as can changes in population distributions.
Population changes may result from people-led activities, for example, changes in land use resulting in new food and water sources, and in some cases, habitat. But wildlife populations also vary naturally in distribution in response to factors such as climate, food availability and predation.
It’s also important to understand that negative impacts caused by native species may be broad, or specific to a particular industry or geographical location – an animal may be considered impact causing in one region but not another.
What problems can native animals cause?
When the balance is upset, populations of native species can have an adverse effect on people, infrastructure, agriculture, native vegetation and on other wildlife.
First Nations elders across the state have also identified cultural impacts such as the degradation of cultural sites and other traditional uses of land.
Economic costs also accrue, including control costs, loss of production, damage to infrastructure, and research and development costs.
Australia’s State of the Environment Report 2021 points out that native species are listed as threats for one-fifth of threatened species, with grazing pressure from macropods (kangaroos and wallabies) the most prevalent.
A South Australian example: kangaroos
Kangaroo numbers have increased substantially since European settlement, with some populations now problematic. Many kangaroos have benefitted from increased access to water, grazing land and the removal of their main predator, the dingo.
Large populations of kangaroos can cause adverse impacts on South Australia’s ecosystems, human activities, public safety due to increased traffic accidents and on the welfare of individual animals, in particular during dry times.
In some circumstances, kangaroos may need to be managed to protect biodiversity, people and property. Implementing kangaroo management may protect the welfare of kangaroos themselves, preventing starvation due to a lack of food during dry times or avoiding car injuries when travelling in search of food or water.
The management of kangaroos is a contentious issue. Depending on an individual’s beliefs they are pests that need to be controlled, a valuable resource that can be sustainably harvested or a national icon that should be preserved.
In 2021 a multi-region, multi-partner project led by the SA Arid Lands Landscape Board was established to address the threat problematic kangaroo populations posed to the condition and resilience of rangelands ecosystems and the enterprises they support.
The project, funded by the Landscape Priorities Fund and due for completion in mid-2023, has brought together stakeholders to explore and trial shared solutions and find the common ground between environmental, economic, social and cultural interests as a basis for shared responsibility for kangaroo management.
More than 20 organisations are partnered with the SA Arid Lands Landscape Board in the project, including the Eyre Peninsula, Northern and Yorke, and Murraylands and Riverland Landscape Boards, Bush Heritage Australia, Conservation Management, Western Local Land Services (NSW), SA Professional Field Processor Association, Ecological Horizons, Nature Foundation SA and the Conservation Council, .
Striking the right balance with kangaroos in the Hills and Fleurieu
Western grey kangaroo numbers have been increasing in the Hills and Fleurieu region for many years.
This has had economic impacts on the region’s agricultural industry as well as posing a significant threat to biodiversity and landscape health.
In some parts of the region, kangaroos can have a greater impact on grazing pressure than declared pest animals such as feral goats, deer and rabbits.
They can damage pasture and crops, prevent regeneration of native vegetation and impact vulnerable ecosystems.
They can also increase costs of conservation and threatened species recovery programs as tree guards and exclusion fencing are required to minimise impacts.
Road safety issues caused by kangaroos are also a legitimate concern, with RAA data confirming that kangaroos account for 71% of vehicle collisions with animals in South Australia, resulting in over 6,000 claims between 2018 and 2021.
How is Landscapes Hills and Fleurieu involved in addressing this issue?
The board’s Regional Grazing Pressure Management program implements a strategic and coordinated approach to reducing grazing pressure across the Hills and Fleurieu region.
The program aims to reduce these impacts in key areas by controlling species which are declared pests under the Landscape South Australia Act 2019 (most commonly feral goats and deer), and by delivering coordinated management of western grey kangaroos in priority locations.
In partnership with the Department for Environment and Water’s National Parks and Wildlife Service, Green Adelaide, ForestrySA, SA Water, and private landholders, the program manages grazing pressure via specialist staff-led operations, and the use of contractors and volunteers to deliver targeted outcomes.
The board facilitates private and public landholders to manage grazing pressure (including by kangaroos) by following stringent safety measures and best-practice methods (for example, National code of practice for the humane shooting of kangaroos and wallabies for non-commercial purposes and the National Code of Practice for the Humane Shooting of Kangaroos and Wallabies for Commercial Purposes).
Managing problematic native species populations
Landscape boards work with state government departments and private land managers to help establish the best course of action for a given situation, in line with the Landscape South Australia Act 2019 and National Parks and Wildlife Act 1972.
While the Department for Environment and Water advocates a living with wildlife approach, in some cases, a native animal population may need to be actively managed to protect biodiversity, reduce the risk of large-scale population starvation or disease, or reduce social and economic impacts on communities.
Landscape boards are typically involved with strategic asset protection, particularly for high value ecological assets such as threatened species sites, recovering prescribed burns/bushfire areas, or revegetation sites.
Depending on the situation and target species, control methods used may include trapping and removal of the animal to a new habitat where they will fit sustainably into the ecosystem, baiting, fumigation, contraception, or culling.
Land managers can apply for destruction permits for certain problematic native species, and some native species, for example, little corellas, don’t need a permit at all. More information about permits to manage, control or destroy wildlife is available from the Department for Environment and Water website.
CSIRO PUBLISHING | The Rangeland Journal (Accessed 19 April 2023)
Department for Environment and Water - Manage, control or destroy… (Accessed 4 May 2023)
Department for Environment and Water - Kangaroo conservation and… (Accessed 19 April 2023)
Department for Environment and Water - Impact causing wildlife (Accessed 4 May 2023)
Striking the right… | Landscape South Australia - Hills and Fleurieu (Accessed 19 April 2023)