World heritage site saved from invasive ant species

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The African big-headed ant. Photo: Eli M. Sarnat from AntWeb

After years of effort, the invasive African big-headed ant (Pheidole megacephala) has successfully been eradicated from Lord Howe Island, an island off the coast of Australia, helping to protect this World Heritage site and its unique diversity of plants and animals. Continue reading

Horizon Scanning for Invasive Species

In this, the era of globalisation, increases in international trade, transport and travel have driven an upsurge in the diversity and volume of non-native species introductions to new areas worldwide. Introduced plant, animal and pathogen species may fail to establish in a new range, and where they do establish, may be environmentally benign. However, there is potential for introduced non-native species to become invasive, even after a (sometimes extensive) period of time without apparent negative impacts.

Preventing the introduction and establishment of a species considered to be an invasion risk is key to mitigating its potential impacts in a new area. For this to be done effectively, it is vitally important that countries conduct horizon scanning initiatives to determine the non-native species likely to arrive, to evaluate the threat posed should the organism become established, to determine by which pathway(s) the organism may be introduced and where appropriate, to convey to the competent authority the requirement for rapid response strategies to alert list species. The recent European Union (EU) draft regulation which aims to legislate for the control of invasive non-native species in the EU is likely to be focused on a list of priority non-native species. A significant number of the species on this list are likely to be alert species not yet present in the region, but which will be determined as threats through the horizon scanning and prioritisation process. The outcomes of this horizon scanning process are likely to be of great interest and importance to various concerned parties across the European continent and beyond, and will certainly be subject to close scrutiny.

Horizon -  Norma Desmond, Flickr
Are invasive species on the horizon?
Photo: Norma Desmond, Flickr

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Lakes poisoned to halt topmouth gudgeon invasion

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.

Topmouth gudgeon (Pseudorasbora parva)
Topmouth gudgeon (Pseudorasbora parva)
(Photo credit: Melania, Wikimedia Commons)

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.

Find out more about the topmouth gudgeon and hundreds of other invasive species at CABI’s open access Invasive Species Compendium.


Dr Paul Fisher
Communications Manager, CABI