Invasion Biology

Sunday, June 04, 2006


Spread and attempted eradication of the grey squirrel (Sciurus carolinensis) in Italy, and consequences for the red squirrel (Sciurus vulgaris) in Eurasia.

In 1997, the National Wildlife Institute, in co-operation with the University of Turin, produced an action plan to eradicate theAmerican grey squirrel from Italy, as this introduced species replaces the native red squirrel through competitive exclusion anddamages trees through de-barking. The first step, a trial eradication of a small population of grey squirrels at Racconigi (Turin) toevaluate the efficiency of the removal techniques, started in May 1997. Preliminary results showed that eradication was feasible, butthe project was opposed by radical animal rights groups which took the National Wildlife Institute to court in June 1997. This legalaction caused a suspension of the project and led to a lengthy judicial enquiry that ended in July 2000 with the acquittal of theInstitute. Nevertheless, the 3-year suspension of all actions led to a significant expansion of the grey squirrel’s range and thus eradicationis no longer considered practical. Therefore, in the medium to long term, grey squirrels are likely to expand through continentalEurasia. This constitutes a major threat to the survival of the red squirrel over a large portion of its distribution range andwill have a significant impact on forests, with economic damage to timber crops.


Difficulty B

Dr Richard Knight Co-ordinator: National Information Society Learnerships - Ecological Informatics
Department of Biodiversity and Conservation Biology University of the Western Cape
Private Bag X17
Bellville 7535

Phone 27 + 21 + 959 3940
Fax 27 + 21 + 959 1237



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