Latest book in the CABI Invasive Series: Parthenium Weed
Parthenium weed (Parthenium hysterophorus) is considered one of the worst weeds in the world. It has invaded and is widespread in about 48 countries in Africa, Asia and the South Pacific, and has the potential to spread to new countries in Africa, Asia and parts of Europe. In the countries it has invaded, it has devastating effects on the livelihoods of millions of people causing significant economic, health and environmental loss. In order to effectively manage parthenium weed and mitigate the impacts it has, one needs a good understanding of the biology and ecology of the weed as well as effective management strategies already utilised. As the editors of CABI’s new book on Parthenium so candidly put, ‘know your enemy’ is the first step in effective management.
CABI scientists have joined an international team of experts who suggest that the large-scale management of a range of some invasive plants could hold the key to reducing the spread of deadly malaria.
Dr Arne Witt and Dr Sean Murphy worked with scientists from the University of Illinois, The Ohio State University and the Fundación para el Estudio de Especies Invasivas (FuEDEI) in Argentina, to conduct a review of existing studies which looked at how mosquitoes are attracted to both land and water-based invasive plants such as water hyacinth, floating pennywort and prosopis and how best these invasive plants can be managed.
Listed as among the Top 100 of the world’s worst invasive species, the coypu (also known as nutria) can cause severe damage to the environment in countries where it is an introduced species. Largely introduced as stock for fur farms and for private ownership, it has spread from its native range in South America to North America, Europe, Africa and Asia. Coypu can be found near rivers, streams, lakes, ponds and brackish marsh in coastal areas.
Several lakes in Hampshire are being poisoned in a bid to control topmouth gudgeon (Pseudorasbora parva), an invasive non-native fish first introduced to Britain in the 1980s which has become more widespread in recent years.
The fish, native to Asia, has spread across much of Europe in recent decades, travelling along waterways and facilitated by illegal fish stocking. Its impacts are significant and include predation on native and farmed fish eggs, resource competition and the ability to host and transmit the rosette agent (Sphaerothecum destruens), a fish parasite that is particularly devastating to Salmonid species such as trout and salmon
The piscicide, Rotenone, is to be applied to the lakes following the removal of native fish in an effort to eradicate topmouth gudgeon whilst limiting non-target impacts. The method has been used by the Environment Agency at a number of sites over the last decade as part of a wider strategy to eradicate topmouth gudgeon from England and Wales. Rotenone breaks down over several weeks, after which the site can be re-stocked with native and/or farmed fish species. Whilst the intervention is fairly drastic, it is considered necessary to prevent the further spread of topmouth gudgeon and limit its likely environmental and economic impacts.
It was confirmed last month that the first population of the forestry pest, the Asian longhorn beetle (ALB), was found in Kent, UK. Forest Research scientists discovered this damaging native of Japan and China infesting around 20 trees, and are now surveying the area to find out the full extent of the infestation. The establishment of this beetle in the UK could be extremely damaging, costing the timber industry millions of pounds, not to mention habitat loss for native species; there is no question that this pest should be eradicated as soon as possible.
An easily overlooked but vitally important component of invasive species management is accurate identification. Picture the scene: It’s Australia, it’s a Friday afternoon, a comprehensive fire ant management strategy has been drawn up, baits have been acquisitioned and an eager team of volunteers is ready to deal with this invasive foe and escape for the weekend. There are plenty of ants around… but nobody knows if they’ve found the right ones because the pesky little critters all look so similar! Scientists in Australia believe they have a solution – a database of 3D images of known species against which 2D photographs of organisms taken and uploaded in the field are compared, giving an estimate of their likely invasive or native status.