Invasive Species

In Australia, invasive species, particular weeds, are an important issue. Weeds can be found along the entirety of Australia’s 60,000km narrow coastline (Cousens et al., 2013). Weeds, as a result of their virility, are now a consistent part of most ecosystems around Australia and interact with all aspects of their environment.

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The topic of invasive flora species is extremely pertinent in Australia, as an island nation, there are many plants that are only found here, for example, 85% of all vascular plants (those with roots, shoots and leaves) are endemic (Hnatiuk, 1990). This endemism means that the protection of native species, and accurate identification of invasive species, is of the utmost importance. However, there is limited information regarding weeds along Australia’s coastline, with what has been referred to as a “vacuum of information” in the management of coastal weeds (Cousens et al., 2013). This is of particular concern in terms of coastal management, which requires accurate and thorough data to ensure the development of proper practices and legislation.

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Weeds have numerous direct and extremely negative impacts on the native environment in Australia. As a result of their ability to grow quickly and tolerance to extremes (e.g. heat floods or soil chemistry), they can take up sunny spaces faster and reach water and nutrients more efficiently than natives can. Additionally, they can alter local chemistry and create a hostile environment for other plants to grow in. This has flow on effects for soil stability, increasing erosion and wind stress on topsoils (Inkson, 2015). Weed species are able to flourish in new environments because they lack co-evolved enemies, as stated by the enemy release hypothesis (Letnic, 2021). Similarly, they are able to impact the viability of native’s seeds which can have long-term impacts on plant populations (Edwards, 2019).

The economic impact of invasive species is significant in Australia; according to the Environment Protection Authority (EPA) (2021), $4 billion is lost per year as a result of weeds impacting agriculture and other industries (Sinden et al., 2004). Indirect effects of weeds are felt in agriculture, horticultural and forestry specifically as a result of quantity and quality reduction resulting from soil chemistry changes, weed control measures and loss of product (Invasive Plants and Animals Committee, 2016).