FENNOSCANDIAN DISTRIBUTION OF THE CALICIALES

Fennoscandia includes the four countries in northern Europe: Norway, Sweden, Denmark, Finland.

For evaluation of the floristic distribution patterns within Fennoscandia we use a system suggested by Bendiksen & Halvorsen (1981) and Okland & Bendiksen (1985). This system includes vegetation zones as described by Ahti et al. (1968). We have placed the species in groups according to the overall appearance of their Fennoscandian distribution patterns as far as it has been possible to ascertain it.

Bendiksen and Halvorsen (1981) divide the Fennoscandian vascular plant flora into five elements: Western, southern, south-eastern, eastern and alpine. In addition we have one group of species with a ubiquitous distribution pattern in Fennoscandia, and a remainder group consisting of species with poorly known distribution patterns. We have added our own data to the known Swedish distributions (Tibell 1977, 1978b, 1980a, Santesson 1984 and IngelÝ g et al. 1984) plus scattered information from Denmark and Finland (Tibell 1969, 1976a, 1978a and 1980b).

The figure shows the total number of species in the seven groups mentioned above. Note the high number of eastern species (16) and the absence of western species (O). Some reasons for this are suggested in the discussion of the eastern element below.

Western element

There are no species in Norway belonging to the western element.

 

Southern element

Factors that may influence the distribution of species belonging to the southern element are: (1) the distribution of the substrate. Several of the lichens are restricted to deciduous trees having a southern distribution in Fennoscandia e.g. Ulmus, Fraxinus, and Quercus. (2) Low temperatures in the summer or low temperatures in the winter may also be delimiting.
The southern element is divided into four groups:
 
S I Strongly southern species. No species occur in this group.
 
S Z Southern species. Five species occur in this group:
Calicium adspersum
Calicium quercinum
Sclerophora farinacea
Sclerophora nivea
Sclerophora peronella
Species in this group occur in the temperate and hemiboreal vegetation zones.
 
S 3 Slightly southern species, including two species:
Calicium corynellum
Chaenotheca carthusiae
Species in this group occur in the temperate, hemiboreal, and south boreal vegetation zones.
 
S 4 Widely distributed species with southern tendency, also including two species:
Calicium glaucellum
Chaenotheca ferruginea
Species in this group occur in the temperate, hemiboreal, south boreal, and middle boreal vegetation zones.
 
 
South-eastern element
 
High summer temperatures seem to be important for species belonging to the south-eastern element, although low winter temperatures cannot be disregarded.
The south-eastern element is divided into four groups:
 
SE 1 Strongly south-eastern species. No species occur in this group.
 
SE 2 South-eastern species. No species in this group.
 
SE 3 Slightly south-eastern species.
Chaenotheca phaeocephala
The species in this group occur as far north as the Nordland province, and they may reach the inner fjords of the Norwegian west coast. (In Sweden Chaenotheca phaeocephala has been collected as far north as Lule Lappmark).
 
SE 4 Widely distributed species with south-eastern tendency. No species occur in this group.
 
 
Eastern element

Several factors have been suggested as important for the distribution of species in the eastern element: (1) The distribution of the substrate. Some of the lichens (Chaenotheca subroscida and Cyphelium karelicum) prefer Picea which has aneastern distribution in Fennoscandia. (2) Low humidity may be significant for some, but not for all species. (3) The snow cover may influence some species. (4) Competition, especially from bryophytes, may be of considerable importance at the Norwegian west coast. Species belonging to the eastern element fall into different ecological groups. Calicium denigratum, C. trabinellum, Cyphelium tigillare and Thelomma ocellatum occur on dry lignum in exposed habitats, while the other species grow under very humid or humid conditions. They occur in root caves, on well decomposed lignum of stumps, or they are corticolous in humid forests. The eastern element is divided into two groups:
E I Eastern species. This group includes 10 species:
Calicium adaequatum
Calicium denigratum
Chaenotheca gracillima
Chaenotheca laevigata
Chaenotheca subroscida
Chaenotheca sulphurea
Cyphelium karelicum
Microcalicium ahlneri
Microcalicium disseminatum
Sclerophora coniophaea
 
E Z Slightly eastern species, including four species.
Calicium trabinellum
Chaenotheca xyloxena
Cyphelium tigillare
Thelomma ocellatum
The species in group E 2 reach the inner fjords of the Norwegian west coast while the species in group E 1 only reach the mountain chain.
 
 
Alpine element
 
Species belonging here probably do not tolerate high summer temperatures.
The alpine element is divided into three groups.
 
A 1 Pronounced alpine species. No species occur in this group.
 
A 2 Boreal-alpine species.
Cyphelium pinicola
The species in this group are mostly distributed in alpine areas, but may also occur in the boreal vegetation zones.
Cyphelium pinicola grows in the most continental areas of Norway. It seems to have a disjunct distribution. The substrate (Pinus) is widely distributed in Norway, and climatic factors must be restricting the distribution of C. pinicola.
 
A 3 Southern hemiboreal-alpine species. No species occur in this group.
 
 
Ubiquitous species

These are widely distributed species in Fennoscandia.
Calicium viride
Calicium salicinum
Chaenotheca brunneola
Chaenotheca chrysocephala
Chaenotheca furfuracea
Chaenotheca gracilenta
Chaenotheca stemonea
Chaenotheca trichialis
Cyphelium inquinans
 
 
Remainder Group

These species have been collected only a few times in Fennoscandia and their distribution patterns are still insufficiently known:
Calicium abietinum
Calicium parvum
Calicium subquercinum
Chaenotheca cinerea
Microcalicium arenarium