What is a native species?

It is a species that is naturally present within a given geographical range where it riginated or arrived without the direct intervention (whether intentional or not) of man.

 What is a semi-native species?

It is a species that was introduced either directly or indirectly by man into a given geographical area during ancient times (before 1500 AD) and is now well-established there.

What is an invasive alien species?
It is an exotic species whose introduction and/or expansion constitutes a threat to biological diversity.

What is an alien species?

It is a species that does not belong to the original flora or fauna of a given geographical area, but which was introduced there (intentionally or not) by man.

What are the possible causes of the alien species introduction?

In Italy, the presence of alien species can be traced to three main factors: accidental introduction, introductions aiming to obtain established populations of exotic species, and escapes from captivity. With regards to the latter, some species were introduced to Italy in order to be farmed for fur or meat, while others were imported for ornamental purposes and were either voluntarily released into the wild or escaped from captivity. Other species are introduced for hunting purposes, in which case they are voluntarily released into the wild, sometimes in large numbers. In some cases the introduced species are quite closely related to native species, leading to the risk of hybridization and genetic pollution. A final category of alien species includes those introduced into other countries which autonomously colonized Italy (secondary introduction).

Where can one find information on alien species?


What are the relevant regulations?

The introduction of alien species is regulated by:

Law n. 394 of 6-12-1991. Framework law on protected areas which prohibits the  introduction of alien plant and animal species that can alter the natural balance.

Law n. 157 of 11 February 1992 n. 157. Article 20 establishes that importing fauna from abroad for release into the wild is only allowed for species that are native to Italy.

Decree of the Republic President n. 357 of 8 September 1997. This decree regulates the procedures for the adoption of the measures established under the Habitat Directive for the purposes of biodiversity conservation.

DPR 357/97 was subsequently modified and amended by DPR 120/03. According to article 5, each intervention which runs the risk of introducing alien species into the wild requires specific authorization on the part of the managing authorities of sites of community interest, based on an environmental impact assessment.

What are the ecological characteristics, the place of origin, and the current distribution of the Black Rat?

Black Rats are Asian in origin; according to some authors, their original range was south-east Asia, while others believe it was the Indian subcontinent. They are though to have been introduced to Italy in paleontological times; the earliest evidence of its presence in Italy comes from Sardinia and is estimated to be about 5,000 years old. They easily adapt to a great variety of habitat, and can live in close contact with humans as well as in more remote areas. Black Rats have been proven to have a negative impact on plant life and on vertebrate and invertebrate fauna both on islands and in continental areas. They can prey on the eggs and nestlings of both ground-nesting and tree-nesting birds. The presence of Black Rats on islands can also contribute to high population densities of native predators such as gulls.

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