Five of the most high-risk freshwater invaders¹ from the Ponto-Caspian region around Turkey and Ukraine are now in Britain -- including the quagga mussel, confirmed just two weeks ago on 1 October in the Wraysbury River near Heathrow airport. Researchers say that, with at least ten more of these high-risk species established just across the channel in Dutch ports, Britain could be on the brink³ of what they describe as an 'invasional meltdown': as positive interactions between invading species cause booming populations that colonise ecosystems⁴ -- with devastating⁶ consequences for native species.

 

The authors of a new study on 23 of high-risk invasive species, published today in the Journal of Applied⁷ Ecology, describe Britain's need to confront the Ponto-Caspian problem -- named for the invaders' homelands of the Black, Azov and Caspian seas -- as a "vital element for national biosecurity."

 

They say monitoring efforts should be focused on areas at most risk of multiple invasions: the lower reaches of the Rivers Great Ouse, Thames and Severn and the Broadlands, where shipping⁸ ballast water and ornamental⁹ plant trading is most likely to inadvertently deposit the cross-channel invaders.

 

All of these areas are projected to see an influx¹⁰ of up to twenty Ponto-Caspian invading species in the near future.

 

"Pretty much everything in our rivers and lakes is directly or indirectly¹¹ vulnerable," said Dr David Aldridge, co-author from the University of Cambridge's Department of Zoology¹², who confirmed the quagga find.

 

"The invader² we are most concerned about is the quagga mussel, which alarmingly was first discovered in the UK just two weeks ago. This pest will smother¹³ and kill our native mussels, block water pipes and foul¹⁴ boat hulls¹⁵. We are also really worried about Ponto-Caspian shrimps¹⁷, which will eat our native shrimps,"

 

The most aggressive invasive shrimp¹⁶ have ominous¹⁸ monikers: the demon¹⁹ shrimp, bloody²⁰ red shrimp and the notorious killer²¹ shrimp -- dubbed²² the 'pink peril²³'.

 

These organisms have already been recorded in Britain, and experts warn they will act as a gateway²⁴ for further species due to favourable²⁵ inter-species interactions that facilitate invasion, such as food provision and 'commensalism' -- in which one species obtains benefits from another's place in an ecosystem⁵.

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