Faunal elements within the Irish Land and Freshwater Molluscs

(adapted from Preston & Hill (1997))

The first digit of the number indicates the major biome category (MBC; emboldened script in column 1); the second digit indicates the eastern limit category (additional descriptors in column 1).

Element/biome Biome Code Definitions Number of species
Arctic-montane 1 Species with their main distribution north of the tree line, in fjelds or tundra. -
Oceanic 11 West European, near coastlines 0
Suboceanic 12 West and central Europe to Germany, Switzerland, eastern France and Italy, but not Poland, eastern Europe or the Balkans. 0
European 13 Europe, including the Caucasus, as far as 60° East. 0
Eurosiberian 14 Eurasia as far as 120° East, including trans-Baikal - west Palaearctic. 0
Eurasian 15 Europe to eastern Siberia beyond 120° East, to the Lena or Amur Rivers - trans-Palaearctic. 0
Circumpolar 16 Eurasia & N. America - Holarctic 2
Boreo-arctic montane 2 Species occurring in both the Arctic-montane and Boreal-montane zones. -
Oceanic 21   0
Suboceanic 22   0
European 23   1
Eurosiberian 24   1
Eurasian 25   1
Circumpolar 26   2
Wide-boreal 3 Species with their main distribution in the Boreal zone, but with wide occurrence in the Arctic and Temperate zones.  
Oceanic 31   0
Suboceanic 32   0
European 33   1
Eurosiberian 34   3
Eurasian 35   2
Circumpolar 36   3
Boreal-montane 4 Species with their main distribution in the coniferous forest zone. This category includes species found at low elevations in the Boreal biome and montane species found within the Temperate biome.  
Oceanic 41   0
Suboceanic 42   1
European 43   3
Eurosiberian 44   2
Eurasian 45   1
Circumpolar 46   1
Boreo-temperate 5 Species which occur more or less equally in the Boreal and Temperate zones.  
Oceanic 51   0
Suboceanic 52   0
European 53   11
Eurosiberian 54   15
Eurasian 55   16
Circumpolar 56   4
Wide-temperate 6 Species with distribution centred on the Temperate zone but found widely in the Boreal and Southern zones - may be absent from the Boreal zone but be subalpine within the Temperate zone. Coastal spp. in this category occur into the Baltic and Black Seas and possibly coastlines in Arctic areas.  
Oceanic 61   0
Suboceanic 62   0
European 63   17
Eurosiberian 64   25
Eurasian 65   31
Circumpolar 66   1
Temperate 7 Species characteristic of the cool Temperate broad-leaved forest zone.  
Oceanic 71   5
Suboceanic 72   5
European 73   11
Eurosiberian 74   7
Eurasian 75   3
Circumpolar 76   0
Southern-temperate 8 Species found more or less equally in the Temperate and Southern zones. Coastal species in this category may occur in the Baltic Provinces.  
Oceanic 81   1
Suboceanic 82   5
European 83   14
Eurosiberian 84   7
Eurasian 85   1
Circumpolar 86   0
Mediterranean-Atlantic 91 Species found across the Mediterranean (both west and east) and the Atlantic fringes of Europe. Coastal species in this group do not extend to the Arctic Ocean or to the Baltic and Black Seas. 8
Submediterranean-Atlantic 92 As for 91 but with a broader range in Europe, extending into south-central areas. 0
Mediterranean-montane 93 Montane in the Southern biome but found in considerably warmer conditions than typical Boreal-montane fauna. 0