Feral pigs can cause extensive environmental, social, cultural, and economic damage. Estimates of agricultural damage (and thus, impacts to economic values), from feral pigs can be hundreds of millions of dollars per year. They predate on native wildlife, destroy habitats, compete for resources with native wildlife, introduce invasive weeds, and disrupt the ecosystem services provided by wetlands. Feral pigs are a perennial management issue with strong seasonality in their impacts. Therefore, managing the impacts from feral pigs on the natural environment, and the ecosystems providing valuable ecosystem services, such as wetlands, requires a whole-of-system, values-based approach.
in Northern Australia and in the Wet Tropics may compete with native bird species, such as brolgas or cassowaries, for tubers and fruits, and can decimate marine turtle nests on beaches in coastal Queensland. Find out more about the ecology of feral pigs.
Impacts to ecological values of wetlands from feral pigs
A small group (or even a single feral pig) can cause significant damage to wetland margins in a very short space of time. Because vegetation plays a critical role in stabilising the land, vegetation destruction by feral pigs can lead to higher rates of erosion and nutrient and sediment resuspension into the water column.
Feral pigs have potentially been impacting Queensland wetlands for hundreds of years, particularly in North Queensland. Impacts from feral pigs to the ecological values of wetlands can include:
habitat alteration and degradation from feeding, trampling, pugging, and wallowing activities
decreased water quality, including decreased water clarity (e.g., increased turbidity), reduced dissolved oxygen levels, and increased nutrient concentrations (e.g., increased ammonium levels)
altered structure of plant communities, leading to increased erosion from vegetation lost and/or structural damage
altered structure of soil microbial communities
spread of introduced weeds and pathogens, leading to the loss of sensitive species
predation on and competition with native wetland animals (e.g., lizards, amphibians, birds, turtles).
Impacts to native wetland animals from feral pigs
Feral pigs prey on native animals found in freshwater (e.g. freshwater crayfish, freshwater turtles) and coastal marine ecosystems (e.g. marine turtle eggs). For example, over 150 freshwater frogs were found in the stomach of a feral pig in Cape York. Feral pigs also are a major predator of freshwater northern longneck turtles in Northern Australia and were found to have direct impacts on the habitat of the rare Jardine River Turtle and the turtle itself. On coastal nesting beaches in Northern Australia, feral pigs consume large amounts of marine turtle eggs, contributing to total egg loss in some instances.
In some instances, the presence of feral pigs can have negative and positive effects on native Australian fauna. In tropical Australian rainforests, feral pig presence has been shown to drive out native birds, likely due to behavioural avoidance by the birds and competition for resources from feral pigs. However, native birds immediately returned to forage on the resources uncovered through feral pig rooting, likely benefiting from increased resource availability before moving on again.
Impacts to water quality from feral pigs
One of the major impacts from feral pig activities in wetlands is on water quality in wetlands. Impacts on water quality from feral pigs can vary across sites due to differing factors but determining specific impacts from pig activities can be difficult. For instance, in unfenced ephemeral floodplain lagoon systems in Northern Queensland, feral pigs destroyed aquatic macrophyte communities and disturbed sediments, significantly affecting water clarity and causing aquatic anaerobic and acidic conditions. Water turbidity caused by pig rooting activities can lower the amount of dissolved oxygen available within the wetland water.
Water quality impacts from feral pigs can affect other wetland species that are reliant on the wetland for survival. For example, decreased dissolved oxygen concentrations in pig-impacted wetlands could lead to higher asphyxia exposure risks to freshwater fish, as identified in the Archer River Catchment in North Queensland, due to shallow and disturbed waters, than in deeper, permanent, and pig-managed wetlands.
Urination and defecation from feral pigs into waterholes and dams can lead to poor water quality, eutrophication, and parasite/disease presence in the water, limiting safe access to surface water for drinking, cultural, and spiritual use by First Nations people.
Impacts to social values of wetlands from feral pigs
In addition to the ecological values impacted by feral pig activities in wetlands, feral pigs can also impact the social values held by the beneficiaries of a wetland. For example, soil disturbance by feral pigs can cause crop damage and transmit diseases to livestock and native wildlife living in wetlands, impacting the services a wetland provides that generate the economic, food security, and biodiversity conservation values enjoyed by beneficiaries. Additionally, feral pigs destroy bush tucker harvest sites, drive out culturally important species, and can destroy culturally important sites.
It is important to note that not all beneficiaries of a wetland view the presence of feral pigs as a negative. Feral pigs are considered an important food, employment, and recreational resource to some Aboriginal Australians from Northern Queensland. Recreational hunters also view feral pigs as a valuable game species, generating both social and economic values for these beneficiaries. A whole-of-system, values-based management approach can be used to ensure that the differing viewpoints of beneficiaries are considered when managing the impacts from feral pigs on wetlands.
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Last updated: 10 May 2021
This page should be cited as:
Department of Environment and Science, Queensland (2021) Feral pigs, WetlandInfo website, accessed 1 July 2022. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/management/pressures/feral-pigs/