Edition 5, June 2010
US Should Clamp Down On Northern Outbreaks Of Climate Change Super Weeds
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June 18th, 2010
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| Kudzu growing out of control. | |
Any northern outbreaks of three highly aggressive weeds invading south-eastern USA should be eradicated to reduce their risk of range expansion under climate change, according to Bethany Bradley and colleagues.
The researchers modelled the potential 2100 range of kudzu (Pueraria lobata), Chinese/European privet (Ligustrum sinense; L. vulgare), and cogongrass (Imperata cylindrica), which are among the most “widespread, aggressive and ecosystem-transforming invasive plants in the south-eastern United States”.
They found that the invasion risk of these weeds would probably expand northward by several hundred kilometers under climate change.
The modelling was based on current climatic envelopes in the non-native range of these plants rather than their native range because “climatic envelopes for the native and non-native ranges of invasive species can be distinctly different”.
Expansions are likely to occur gradually for kudzu and cogongrass, through seed dispersal over short distances (eg. wind, water or animal-borne) and long distances (eg. accidentally via vehicles).
Recent northward expansion of kudzu, which causes damage estimated at $100–500 million a year, has been linked to higher winter temperatures, which reduce the duration of kudzu-killing frosts.
Existing seed sources of privet in northern states due to its use in landscaping could facilitate rapid invasion of forested areas under climate change.
As well as eradicating pockets of these weeds in northern states, management recommendations include controlling invasive populations along their northern borders and planning to prevent invasion into new areas.
References
Bradley BA, Wilcove DS and Oppenheimer M. 2010. Climate change increases risk of plant invasion in the Eastern United States. Biological Invasions 12(6): 1855-187