Risk of extincion

Introduced species from other geographical areas represent a serious threat to biodiversity, causing the decline or even the extinction of many native species.

A well known case of introduced species that endangers a native species is the introduction in Britain, Ireland and Italy of the American grey squirrel (Sciurus carolinensis). This species has been able to adapt to new areas and spread rapidly. Evidence points out that where grey squirrel is introduced, this leads to a rapid disappearance of the native red squirrel. The phenomenon has been extensively studied in Great Britain and scientific data collected give evidence of the competition between the two species, that inevitably lead to a local extinction of the red squirrel, In time the “local” extinction becomes more widespread.
Unfortunately, the result is always unfavorable to the native species: when the grey squirrel appears, the red squirrel becomes extinct in a short time.

Decline of the red squirrel (in red) and spread of the grey squirrel (grey) in Great Britain and Ireland from 1945 to 2010; orange areas of overlap of the two species (taken from Red Squirrel Survival Trust website www.rsst. org.uk).

The presence of the grey squirrel in Britain and Ireland, as these islands, is a serious problem for these islands, but it’s a local problem, fortunately being these islands. The presence of the species in Italy instead is, in fact, a serious risk to the survival of the red squirrel, not only in our country but also in the near countries of France and Switzerland and, in the long term, throughout the European continent.

Unlike Great Britain and Ireland, Italy is not an island and the populations of grey squirrel from here may expand in Europe. According to statistical prediction models that simulate the possible expansion of the grey squirrel in the medium term and that have been specially formulated and believed to be reliable in the scientific international community grey squirrel can, in time, colonize the Alps, the Apennines and the Alpine countries such as France and Switzerland.

The survival of the red squirrel is then linked to the possibility of halting the spread of the grey squirrel in Italy and in the rest of Europe.