Invasive alien species in Switzerland - Schweizer ...

An inventory of alien species and their threat to biodiversity and economy in Switzerland FOEN 2006 134
Fig. 10.2 > Status of alien species in Switzerland.
Unknown
22%
Invasive
5.5%
Naturalized
28%
Adventive
22%
Subspont.
28%
10.5 Naturalized species of Switzerland
Naturalized species are represented by 102 species belonging to 49 plant families, i.e.
less than one-third of the total number of families in Switzerland (Table 10.7). The
majority (30 families) include only one naturalized species. Eleven families include
two naturalized species, and only eight families have more than two naturalized species.
The Asteraceae alone includes ten naturalized species followed by the Rosaceae
(nine), the Brassicaceae (seven) and the Fabaceae (six). Almost one-third of all naturalized
species belong to one of these four families.
The percentage of naturalized species per family ranges from 0.8 % (Caryophyllaceae)
to 100 % for eight families that are represented exclusively by their naturalized species
(usually one species – with the exception of the Phytolaccaceae which is represented
by two species) (Table 10.7). The percentage of naturalized species in the large families
(>30 species) ranges from 0.8 % (Caryophyllaceae) to 7.7 % (Polygonaceae). The
largest family, Asteraceae, comprises 2.9 % naturalized species. The aquatic plant
family Hydrocharitaceae comprises 71.4 % naturalized species.
Fig. 10.3 > Number of established species as a function of the number of alien species (r 2 =0.8).
No. of naturalized species /
family
12
10
8
6
4
2
0
0 5 10 15 20 25 30 35 40
No. of exotic species / family