Invasive species have already caused at least 45 extinctions of unique Australian wildlife and they imperil 42% of nationally listed threatened species (to a high or medium degree). Australian species are highly susceptible to predation, competition and suppression by introduced species because they have mostly evolved in isolation for tens of millions of years.
It took feral cats and foxes only 70 years or so to spread across most of the Australian continent, but many other introduced species are still in the early stages of invasion. If allowed to spread and multiply to their full potential, they will change Australia beyond all recognition and obliterate hundreds more species.
To overcome the environmental threats of invasive species, Australia needs more effective federal and state/territory laws, policies and programs to:
- prevent harmful new invaders from arriving and establishing in Australia
- eradicate harmful new or emerging invaders become they become entrenched
- contain harmful invaders to stop them spreading into new regions
- manage harmful invaders to reduce their harm and protect Australian species and ecological communities.
Invasive species have already caused dozens of extinctions in Australia – more than any other threat – and they imperil more than 80% of our nationally listed threatened species. Since European colonisation, invasive species have been primarily responsible for 45 of the 100 confirmed extinctions of endemic species, including 30 mammals, and have contributed to 34 other extinctions.
Threat Guides have been developed for feral pigs, rabbits and Phytophthora dieback.
Feral pigs (Sus scrofas) imperil at least 149 nationally listed threatened species. They prey on native animals and plants, dig up large expanses of soil and vegetation in search of food, and foul fresh water. They also host diseases that can be transmitted to other species.
“Without clear policies to regenerate degraded forests and protect existing tracts at a massive scale, Australia stands to lose a large proportion of its remaining endemic biodiversity.” – Bradshaw 2012
Phytophthora cinnamomi is a soil-borne, microscopic water mould that causes a severe plant disease known as Phytophthora root rot or dieback. It imperils 236 nationally listed threatened species and 32 threatened ecological communities.
The European rabbit (Oryctolagus cuniculus) imperils 321 nationally listed threatened species, 21% of Australia’s total, more than any other invasive species. It also threatens 9 ecological communities.