According to the March 26, 2009 CSIRO media release Climate change may wake up ‘sleeper’ weeds, “Climate change will cause some of Australia’s potential weeds to move south by up to 1000km [kilometers], according to a report by scientists at CSIRO’s Climate Adaptation Flagship.”
The Climate Adaptation Flagship is one of nine Flagships initiated by CSIRO (short for Commonwealth Scientific and Industrial Research Organisation) in order to provide science-based solutions to the problems facing Australia.
Dr. John K. Scott, a principle research scientist at CSIRO, spoke about this problem at the GREENHOUSE 09 climate-change conference held in Perth on March 23-26, 2009.
Scott stated, “Out there, throughout the nation, are many weed species lying low but with the potential to take off and add to the economic and social burden of weed control.”
He adds, “One critical unknown is what these lurking weeds will do under climate change. Will their distributions change? Will they spread north or south, east or west, and will these movements change them into full-blown pest species?”
These “sleeper” species, the classification they are called in agriculture, are weeds that normally are dormant or benign because the climate is not conductive to their growth.
However, with warmer temperatures throughout the world, many of these weed species are taking on a new life. They post a threat to agriculture in Australia but also to the natural environment, where they are called “alert” species.
Page two talks more about sleeper weeds, along with adding further comments from Dr. Scott.
Sleeper weeds may suddenly appear after certain natural occurrences such as drought, flood, fire, climate change, or change in land or water management.
The website states, “Sleeper weeds are not always recognised as a significant problem, even though the potential threat they pose to industry, people or the environment may be extreme.”
Dr. Scott, a weed and insect ecology and biological control expert, described their likely movement in our warmer climate, “We found that climate change will cause most of these weeds to shift south, with wet tropical species making the greatest move – over 1000km.”
And, “The regions most at threat from alert and sleeper weeds, both under the current climate and under climate change, are south east Australia, followed by the south west.”
The sleeper weed species found to “pose the greatest threat under climate change” are the: Karroo thorn (Acacia karroo), rosewood (Tipuana tipu) and kochia (Bassia scoparia).
The two sleeper species found to have the “highest risk of establishing [themselves] in new areas” were the: white weeping broom (Retama raetam) and fringed dodder (Cuscuta suaveolens).
Dr. Scott contends that: “The predicted move south by both native and introduced plants would produce a ‘vacuum’ in northern Australia so, to prevent lurking species from invading, a new list of alert and sleeper weeds for this region needs to be developed.”
To learn more about weeds in Australia, go to the Australian Government website "About Weeds."
You might think they are only weeds, but the Australian Goverment has a different view on them. It states, "Invasive weeds are among the most serious threats to Australia's natural environment and primary production industries. Weeds have major economic, environmental and social impacts in Australia, causing damage to natural landscapes, agricultural lands, waterways and coastal areas."