Invasive Species – Background Information

Biosecurity & Invasive Species

The native plants and animals of the Northern Agricultural Region adapted to life on an isolated continent over millions of years. Since European settlement, they have had to compete with a range of introduced species, including some new predators. Introduced species can spread rapidly and become invasive once they have established populations in new areas. This is often because they are released from the natural predators and fatal diseases that control their numbers at home. Some also have high reproductive rates. Invasive species can have an adverse and often very damaging impact on people, agriculture and the natural environment. Feral animals can compete with and predate on wildlife and livestock. They can also spread diseases and parasites and cause soil erosion in degraded areas, including waterways. Weeds are a significant threat to our natural landscapes, agricultural lands, waterways and coastal areas because they displace native species and contribute to land degradation. The prevalence of invasive species can exacerbate the impact of land use change and climate change (DAWE 2020; DPIRD 2020).

Methods of controlling invasive species include localised eradication, periodic reduction, sustained reduction, removal of the most destructive individuals or exclusion of invasive species from a predetermined area (Australian Weed Strategy and Pest Animal Strategy; DAWE 2020). The main aim of invasive species management is to prevent invasions. Once a species has become established, the focus is on minimising the damage it causes in the most cost-effective way. Conventional control methods for feral animals include trapping, baiting, fencing and shooting. Conventional control methods for invasive weeds include manual removal of weeds and treatment with herbicides. Biological controls can be effective in some cases. Rabbits  and Paterson’s Curse are two good examples. Prevention, detection and early intervention are crucial to prevent new invasive species from becoming established. As invasive species rarely respect land tenure boundaries, coordinated effort amongst many different landholders is required to effectively manage invasive species (DAWE 2020; DPIRD 2020).

Invasive species also directly threaten the traditional way of life of many Aboriginal people across the region. Invasive species can seriously affect the growth and survival of natural timbers, livestock, crops, fish stocks, plants and animals. Aboriginal people in the region rely on these resource for food and cultural practices. Aboriginal groups across Australia successfully manage invasive species using traditional land management techniques such as cultural fire, participatory mapping, place-based management bringing cultural values to the fore, exclusion fences and trapping and removal of feral animals. Managing weeds and feral animals contributes to caring for Country and provides employment and training opportunities for Aboriginal people (Ens et al 2015, Western Mulga). Invasive species management is not only a technical, economic and environmental issue. It is also, fundamentally, about the relationships between people and their lands and waters and Traditional Owner’s knowledge and priorities must be a central part of planning processes to manage invasive species.