ACTA PHYTOGEOGRAPHICA SUECICA 82 EDIDIT SVENSKA VAXTGEOGRAFISKA SALLSKAPET
Risto Virtanen and Seppo Eurola
Middle oroarctic vegetation
in Finland and middle-northern
arctic vegetation on Svalbard
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Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 3
Abstract. Risto Virtanen and Seppo Eurola. 1 997. Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard - Acta Phytogeogr. Suec. 82, Uppsala, 60 pp. ISBN 9 1 -72 1 0-082-6. (9 1 -72 1 0-482-5 . )
Plant communities of the middle oroarctic zone of northwestern Fennoscandia and middle-northern arctic areas of Svalbard were studied to describe the community types and their ecological relationships. The analyses were based on data sets collected both from subcontinental mountains of Finnish Lapland and from a geographically broad area of Spitsbergen, the main island of Svalbard. Plant communities were classified by a divisive clustering method (TWINSPAN) and the ecological relationships of the community clusters were examined by detrended correspondence analysis (DCA) . For northern Fennoscandia, edaphical ly differentiated series of community types from windexposed ridges to depression sites with snowbed vegetation were described. On siliceous substrates, the types in the series conformed to those described earlier. On calcareous soi l , the Dryas octopetala-Carex rupestris type occupied exposed ridges, the Cassiope tetragona-Dryas octopetala type sites with moderate snow cover, and the Salix polaris-Silene acaulis type moderate snowbed sites, while late snowbed sites harboured communities of the Saxifraga oppositifolia-Ranunculus sulphureus type. For Spitsbergen, the following three regionally distinguished series were described: ( 1 ) In the inner fjord region, wind-swept ridges were character
ized by the Saxifraga oppositifolia-Hypnum revolutum community. This community shows a gradual transition to communities rich in Dryas octopetala and mosses on sheltered slopes.
(2) At the southwestern-western coastal region, ridges were occupied by communities characterized by Racomitrium lanuginosum. These graded to moss and lichen-rich heaths, while depression sites harboured snow bed communities dominated by Sanionia.
(3) In the Dryas region, ridge heaths approached the vegetation of polar deserts. The sheltered sites were characterized by moss tundra communities and Sanionia snowbeds.
On the mountains of northern Fennoscandia, the plant communities seemed to be clearly differentiated in relation to the bedrock. On Spitsbergen, some edaphic differentiations exist among plant communities, but some of the differences obviously reflected climatic differences among the areas studied.
It was shown that the sheltered slopes and snowbed sites of Spitsbergen harbour copious moss vegetation dominated by robust (mainly pleurocarpic) mosses, whereas the corresponding habitats in northern Fennoscandia seem to consist of small bryophytes growing together with prostrate vascular plants and lichens. One reason for this may be the absence of herbivores (Norway lemming or brown lemming) feeding on mosses on Spitsbergen.
Nomenclature: Vascular plants (Lid & Lid 1 994), bryophytes (Soderstrom et al. 1 992) and lichens (Santesson 1 993 ; Andreev et al. 1 996).
Risto Virtanen and Seppo Eurola, Department of Biology, University of Oulu, P 0. Box 333, F/N-90571 Oulu, Finland.
Acta Phytogeogr. Suec. 82
Contents
1 Introduction
2 Material and Methods
2. 1 Sampling methods, sampled areas and their environmental characteristics
2.2 Climate
2.3 Grazer communities
2.4 Numerical analyses
3 Results: classification and ordination
3. 1 Northwestern Fennoscandia
3 . 1 . 1 Festuca ovina-Potentilla crantzii group
3 . 1 .2 Alectoria group
3. 1 .3 ]uncus trifidus-Cassiope tetragona group
3 . 1 .4 Salix herbacea group
3. 1 .5 Ranunculus glacialis group
3. 1 .6 Saxifraga oppositifolia group
3.2 Spitsbergen
3 .2. 1 Luzula confusa group
3 .2.2 Papaver dahlianum group
3 .2.3 Dryas octopetala group
3 .2.4 Alopecurus borealis-Aulacomnium turgidum group
3 .2.5 Sanionia snowbeds
3 .2.6 Wet moss snowbeds
4 Topographic patterns: series of communities in ridge-depression transects
4.1 Northwestern Fennoscandia
4.2 Spitsbergen
5 Vegetational differentiation in relation to edaphic factors
6 Abundance patterns of bryophytes in topographic and regional gradients
7 Acknowledgements
8 References
Appendices
5
6
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1 Introduction
The Fennoscandian oroarctic (alpine) vegetation has been
subject of study in many classic works (Wahlenberg 1 8 1 2;
Nordhagen 1 928, 1 943; Kalliola 1 939; Gjrerevoll 1 956;
Dahl 1 957) providing a comprehensive reference to veg
etation types and their ecology . These studies mainly
concentrate on the vegetation of south-central Scandina
vian mountains and are restricted to the lower oroarctic
zone. From the middle oroarctic zone in the North, rather
tentative descriptions are available (Fries 1 9 1 3; N ordhagen
1 936, 1 955; Hedberg et al . 1 952). Most recent gradient
studies of oroarctic vegetation covering a broad geo
graphic area in northern Fennoscandia include main topo
graphic, altitudinal and regional patterns of oligotrophic
mountain heath vegetation with a large number of sam
ples (Haapasaari 1988; Oksanen & Virtanen 1995) . These
studies outline the vegetational relationships between
Fennoscandian mountain vegetation and the vegetation of
truly arctic areas. Gross climatically parallel areas for the
middle oroarctic zone (Ahti et al. 1 968) exist on Spitsbergen
where we also encounter gradients to northern arctic
tundra and polar desert zones (Elvebakk 1985) . The veg
etation of Spitsbergen has been treated in several works
since the twenties (e.g. Summerhayes & Elton 1 923,
1 928; Acock 1 940; Hadac 1 946; R(Zjnning 1 965; Eurola
1 968; Hofmann 1 968; Hartmann 1 980; see also Elvebakk
1 994). The approaches used in these studies reflect the
ideas of many phytosociological schools. Consequently,
the described vegetational noda are not always easily
comparable (Walker et al. 1 994), and it is sometimes
difficult to determine whether differences or similarities
in vegetation are real or whether they reflect methodo
logical differences between different authors. This has in
part hampered ecological comparisons between truly arc
tic vegetation and the vegetation on the mountains of
northern Fennoscandia. In the present paper, we have aimed to start by classifying plant communities based on
samples collected in a directly comparable way from
northern Fennoscandia and Spitsbergen, compare the de
scribed community types with those found in the earlier
literature, analyse the main gradients by indirect ordina
tion, and summarize the main vegetation patterns in the
form of mesoscale vegetation series. Thereafter, we dis
cuss the role of edaphic factors in differentiating commu
nities and patterns in bryophyte abundance.
Acta Phytogeogr. Suec. 82
2 Material and Methods
2.1 Sampling methods, sampled areas and their environmental characteristics
The material was collected during several occasions over a long period, and consequently the procedures used by us
were prone to variation in sample plot size and method of
placement of the sampling plot (Table 1 ) . One of the main
criteria was to sample the variation of vegetation along
presumed main ecological gradients (soil, topography) to
a large extent. Consequently, wind-exposed sites, late
snowbeds and various heath types were analyzed both on calcareous and more or less siliceous substrates. The
sampled sites were mostly underlain by glacial till . The
azonal vegetation on other soil-types, e.g. coastal pla
teaux with deltas, moraines or clay fields with sparse
vegetation were not sampled. A systematic sampling along
ridge-depression topographic transects was favoured when
ever possible. Species cover was estimated with the Hult
Sernander five-unit scale, with an added symbol '+' for
very low abundance, or by a direct estimation of percent
age cover. The cover was noted as an estimate of the area
of foliage projection for each species.
In northwestern Fennoscandia, the vegetation was sam
pled on subcontinental mountains of the northwestern
Enontekio community. One part of the material was sam
pled at Lake Kilpisjarvi (473 m above sea level, 69° 03' N,
20° 50' E) where mountains reach to altitudes of more
than 1 000 m above sea level. Many of the mountains are
characterized by overthrown Caledonian nappes with rela
tive altitudinal differences of more than 500 m (Fig. 1).
Fig. 1 . View over the mountains near Kilpisjarvi. Mt. Jehk:ats, alt. 950 m, with middle oroarctic heath vegetation. August 1 987. (Photo: Risto Virtanen.)
Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 7
The other part of the data was sampled from mountains northeast of Kilpisjarvi, where the valley between the mountain Guonjarvam (69° 07' N, 21 o 10' E) and Duoljehuhput was one of the main sampling areas. The mountain slopes are mainly gentle, shaped by continental ice sheets, reaching altitudes of more than 900 m above sea level, while the mountain tops reach altitudes of about 1100 m. The terrains are mostly covered by soil cover, contrasting with the vast stone-block districts north of this area (the Gahpperus-GoddeniSsak area). The soil formations are often modified by cryoactivity that maintains polygonal stone rings (Ohlson 1964 ). The sites comprise both siliceous and calcareous soil substrates (Uusinoka 1980) which reflect the occurrence of bedrock both with calcium carbonate-rich caledonic dolomites and silicate-rich mountain schists.
On Spitsbergen, the study sites were more broadly distributed in three main areas. The first of the study areas was the inner fjord region of Isfjorden 08° 10' N, 15° 40' E), where most of the samples were obtained from the Adventdalen-Sassendalen area. The second area extended from the west-southwestern coastal area of Hornsund or 00' N, 15° 40' E) to the mouth oflsfjorden. The exact location of the sample sites of these two subareas is given by Eurola (1968). The third study area ranged from the Slettvika-NordenskiOlddalen area at the bottom of Van Mijenfjorden or 50' N, 16° 40' E) to Agardhdalen on the southeastern coast of Spitsbergen 08° 10' N, 18° 20' E) (Fig. 2).
In the inner fjord area, the Triassic, Jurassic and Cretaceous sediments prevail (Major & Nagy 1972). The mountains on both sides of Adventfjorden consist basically of Cretaceous sediments, overlain by lower Tertiary strata. At Sassenfjorden, the bottom part of the valley is built up of Permo-Carboniferous sediments (Winsnes et al. 1962). The coastal areas consist mostly of Hecla Hoek rocks composed of Proterozoic and older Paleozoic sediments and they were strongly faulted and metamorphozed during the Caledonian orogeny. The studied sites at Isbjornhamna are composed mostly of gametiferous mica schists
intercalated with marbles. The bottom of the Van Mijenfjorden area is composed of Tertiary deposits which are replaced by the Triassic, Jurassic and Cretaceous sediments in the Kjellstromdalen-Agardhdalen area. Considering Elvebakk's (1982) analyses, the Hecla Hoek bedrock-based substrates and those with mesozoic deposits give variable reactions from acidic to alkaline. The material from Spitsbergen was chiefly collected in areas where parent material of soils is circumneutral, and sampling sites with clearly siliceous and strongly alkaline parent material were not covered by us. This differed from the situation of northern Fennoscandia where parent material was more distinctly differentiated into siliceous and calcareous ones.
2.2 Climate
Climatological data from the studied mountain sites at northwestern Fennoscandia are scarce as there are no meteorological stations at higher altitudes. To provide some estimates for the climatic conditions in our study area in northwestern Fennoscandia, we calculated mean temperatures for locations at 880 m above sea level based on data from the weather station at Kilpisjarvi (Fig. 3). The records were available for the subalpine forest zone (altitude 480 m a.s.l., Jarvinen 1987). The transformation was performed according to recommendations of the N orwegian Meteorological Institute to use a cooling rate for periods December - February of 0.5 oC/100 m, March August 0.7°C, September - November 0.6°C. Some measurements were available for the alpine belt about 40 km west of the study sites (Mook & Vorren 1990). Mook & V orren ( 1990) gave data for the period June - October for altitudes 915 m and 1110 m measured 20 cm aboveground. The mean temperatures for the station at 915 m for the months June - October were as follows: 6.2, 6.4, 8.7, 2.7 and- 2.2°C, and for 1110 m 1.3, 1.8, 3.9,- 2.4 and - 4.8°C, respectively. These values indicated that temperatures decreased by ea. five degrees for every 200
Table 1 . Sample material from northern Fennoscandia and Spitsbergen. N = no. of samples.
Northwestern Fennoscandia Mts. at Kilpisjarvi Mt. Guonjarvam and Gahpperussak
Spit bergen SW-W coast (Hornsund) - Inner fjord area Kjellstrom-Agardhdalen area
* Data from Eurola ( 1968)
Plot size (m2)
0.25 4
25 25
N
126 81
58 56
Year of sampling
1986 1989-90
1964 *
1969
Acta Phytogeogr. Suec. 82
8 R. Virtanen & S. Eurola
Fig. 2. View over Mt. Friedrichfjellet, midway between Agardhdalen and Bellsunddalen. Moss-rich tundra and Bjarrnebreen. July 1 969. (Photo: Seppo Eurola. )
m increase in altitude. As the highest station was on the peak of the mountain, it might have been climatically pronouncedly extreme. Mook & Vorren (1990) also gave recorded minimum temperatures in June-August. At an altitude of 915 m, these were - 3.8,- 0.1 and - 1.5 oc, while values at 1110 m were - 6.3, - 4 .3 and - 6.5 oc, respectively.
The temperature data for Spitsbergen (Fig. 3) were obtained from the records of three meteorological stations encompassing the study areas (Steffensen 1982). Isfjord weather station was a coastal station, while Longyearbyen represented an inland station, and the data available from Hopen probably corresponded closest to conditions prevailing at the Agardhdalen region. We found published data from Hornsund for a one-year-period only 1957-1958 (Eurola 1968).
The temperature curves of northwestern Fennoscandia and Spitsbergen show that (1) winter temperature regimes are practically similar, but near-ground temperatures are probably lower in Spitsbergen due to thin snow cover (see below), (2) the calculated values for mean temperatures of the growing season in the lower part of the middle oroarctic zone of northern Fennoscandia are higher than those at
Acta Phytogeogr. Suec. 82
any area on Spitsbergen. In the upper altitudinal limit of the zone they are equal or even colder than in the most areas of Spitsbergen, as indicated by the data in Mook & Vorren (1990). The majority of samples of Fennoscandia are from altitudes over 900 m above sea level, and thus, the actual temperature regimes are more similar than indicated by the graphs, (3) differences between maximum and minimum temperatures are greater in Fennoscandia than on Spitsbergen, (4) the values of Hopen indicate a colder climate corresponding to northern arctic or upper oroarctic zones (Mook & Vorren 1990), and 5) night frosts in the summer are more infrequent at Spitsbergen than on the mountains of northern Fennoscandia. On Spitsbergen, some frosts of - 1.8°C were recorded only in July-August (Steffensen 1982).
Precipitation data were taken from the meteorological station reports (Steffensen 1982, Finnish Meteorological Institute) and should be considered as estimates for the actual rain fall (Fig. 3). The precipitation curves show more variation than the temperature does. In northwestern Fennoscandia ( Kilpisji:irvi area) the curve shows a relatively high amount of summer precipitation. In the inner fjord region of Spitsbergen the annual rainfall is the
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 9
1 0
5 c
0 i E � -5 ! 0 -1 0 E
� 0 E c
- 1 5
-20
70
60
50
40
2 30 E 20 E
1 0
0 c a
-,
a)
b)
a :; 0 � -, 0
• Kilplsjarvl 880 m
--+-- Longyearbyen
• lsfjord Radio
--o- Hopen
o. Hornsund
-••- Kllplsjarvl
--+-- Longyearbyen
• lsfjord Radio
--o- Hopen
----b- Hornsund
Fig. 3. Temperature (a) and precipitation (b) characteri tics of the study areas. Kilpisjarvi : the monthly mean temperatures for north we tern Fennoscandia. Calculated values for 880 m above sea level based on the data of the weather station at Kilpisjarvi ( 480 m above sea level) . The transformation as performed according to lapse rates for the periods December-February 0.5° C/ 1 00 m, MarchAugust O.r C, September-November 0.6° C. Other stations on Spitsbergen and Hopen according to Steffensen ( 1 982). The data for Homsund are from graphs in Eurola ( 1 968), based on measurements of 1 957- 1 958. The precipitation values ofHomsund are smoothed using running means of two successive month .
lowest: the annual mean precipitation in Longyearbyen is 208 mm. The coastal areas, western Isfjord and Hornsund receive about 400-450 mm. On Hopen, the annual mean is 400 mm. The inland station, Longyearbyen, shows the lowest values during the winter months. In the coastal area, the winter precipitation is relatively high. The low winter precipitation of the inner fjord region is in accordance with the typical situation in the circumpolar Arctic (Aleksandrova 1 988; Oksanen & Virtanen 1 995), while the relatively high values of the coastal areas indicate a higher degree of oceanity.
Little information is available on snow conditions
during winter. As a rule, the snow cover is thicker on mountains of northwestern Fennoscandia than on Spitsbergen. In the birch forest zone of the Kilpisjarvi area, the mean maximum snow depth is about 70 cm ( Hiltunen 1980). Above the treeline the distribution of snow is more variable and in depression sites the depth is usually 1 -2 metres or more. The soils in the snow bed sites are frozen during winter ( Hiltunen 1 980). The snow depth data from Svalbard are even more scanty than in northwestern Fennoscandia. According to the records available, the maximum averages are about 30 cm in the inner fjord region (Eurola 1 968). In depressions there can be
Acta Phytogeogr. Suec. 82
10 R. Virtanen & S. Eurola
deep snow fields. The situation at Spitsbergen may correspond to that recorded at Barrow, northern coast of Alaska. According to Dingman et al. (1980), the temperature on the soil surface can be- 25°C in the coldest periods of the winter. The thin snow cover gives weak insulation, and thus the ground is exposed to extreme low temperatures. Permafrost is omnipresent on Spitsbergen and plays a significant role for site conditions (Eurola 1968; R�nning 1969; Stablein 1971).
2.3 Grazer communities
The middle oroarctic zone represents an ecosystem approaching the limits of closed vegetation cover that is relatively low productive with sparse annual biomass production. The plant production supports a trophic system with several grazers (Oksanen et al. 1996) of which reindeer and small mammals are the most important. In the district studied by us the reindeer population consisted of ea. 10 000 animals in the late 1980s which is about 1-4 individuals per km2 ( Kojola et al. 1993), but has decreased to ea. 6000 in the 1990s (1. Kojola, pers. comm.). Reindeer grazing is most intense in mid-summer. The key-stone small mammal of the study sites is the Norway lemming (Lemmus lemmus) showing drastic variation in densities. It may be virtually absent for periods up to 15 years, then copiously abundant during big outbreaks ( Kalela 1961). Mountain hare (Lepus
timidus), rock ptarmigan (Lagopus mutus) and arvicolids (Microtus agrestis, M. oeconomus and Clethrionomys
rufocanus) occur in the oroarctic zone ( Henttonen et al. 1977), but they fluctuate in density ( Laine & Henttonen 1983).
On Spitsbergen, the Svalbard reindeer (Rangifer
tarandus platyrhynchus) is the main grazer and totals 1 1 000 individuals (Norderhaug & Reimers 1976). The metapopulation is divided into several relatively discrete populations (Punsvik et al. 1980). In the inner Isfjorden region, the estimated density in areas close to the study plots has been 5.6 animals per km2 (Alendal & Byrkjedal 1976). A population has been observed in the ReindalenSveagruva-Agardhdalen area. On the west coast, reindeer has occurred sparsely. Another herbivore, the Svalbard ptarmigan (Lagopus mutus hyperboreus) occurs, but estimates of the population are unknown. In the Sveagruva area, an introduced muskox (Ovibos moschatus) population numbered 16 individuals in 1930 and some tens of individuals in the 1960s (pers. observ. by S.E.). This population has obviously become extinct in the late 1980s (Mehlum 1990). There are no lemmings on Spitsbergen, and small populations of Microtus epiroticus
(including M. arvalis) are only found near human settlements (Mehlum 1990).
Acta Phytogeogr. Suec. 82
2.4 Numerical analyses
Despite the materials containing sample plots of different sizes and the abundance values being estimated by different methods, we found it beneficial to jointly analyze the data sets in order to directly compare the vegetation units (Podani 1984: 80-83). For the numerical analyses, the cover classes were transformed to corresponding percentage classes (Oksanen 1976). Numerical analyses of the vegetation data were performed using these percentages. The TWINSPAN-clustering ( Hill 1979) was used to produce a classification for the plant communities. In the TWINSP AN run, the number of pseudospecies cut levels were set to three, with levels 0, 4, and 10. These levels produced a number of pseudospecies not exceeding the computation capacity of the TWINMAX - an enlarged programme version of TWINSPAN. On the other hand, these levels should not emphasize the influence of the dominant species, and the species occurring with low cover values should affect the classification. Thus the whole species composition, not only the dominant species, contributes to the classification. TWINSP AN divisions with eigenvalue > 0.2 were employed to produce a classification. The higher level clusters of TWINSP AN were used for arrangement of the community groups. To briefly convey an idea about the ecological characteristics of the groups, a physiognomic-site type name was also given. The subdivisions of these groups resulted in clusters that were regarded as community types or variants thereof. The community types were expected to have a characteristic species composition and to be ecologically interpretable. The variants shared much of the ecology of the main type, but the species composition and abundance relationships were likely to vary depending on local factors. We described the Fennoscandian community types as bound to the Finnish site-type system (e.g. Haapasaari 1988), while the vegetation units on Spitsbergen were called 'communities'.
Detrended correspondence analysis ( DCA) ordination (Hill & Gauch 1980) was used to reveal the major directions of variation (vegetation gradients) in the community data. Since TWINSP AN clearly divided the material into 'Spitsbergen' and 'Fennoscandia' as main groups of their own, separate ordinations were performed for northern Fennoscandia and Spitsbergen. The centroids (mean of the ordination scores for the first two DCA axes) of the TWINSPAN groups (community types) were calculated and standard deviation of the mean was calculated to indicate the dispersion of the plots. DCA scores were computed by the CANOCO 3.1 computer package (ter Braak 1988, 1990) using down-weighing of rare species and detrending by segments. Sample plots of wet and rocky habitats were omitted from the ordination, because they behaved as outliers.
3 Results: classification and ordination
In the first division of the TWINSPAN run (Fig. 4), the sample plots from northwestern Fennoscandia and Spitsbergen were practically exclusively separated from each other as only one plot from Fennoscandia was assigned to the cluster of Spitsbergen data. A more diffuse discrimination could have been expected due to the largely common species pool occupying climatically relatively similar areas, especially on geologically corresponding substrates. Nevertheless, this result indicates that communities in similar habitats are differentiated. This is partly due to differences in species composition between Fennoscandia and Spitsbergen. The differences in species composition are exemplified by the preferential species list given by TWINSP AN (Table 2). A corresponding result was also obtained in an analysis of data sets from Bear Island, Jan Mayen, Spitsbergen and the mainland ( Virtanen et al. 1997b). Due to this dichotomy, the communities of northwestern Fennoscandia and Spitsbergen are treated in separate sections.
0.502
FovPcrG AG JtCtG ShG RgG SoppG
3.1 Northwestern Fennoscandia
The total material of northwestern Fennoscandia was firstly split by TW INSP AN into two large groups consisting of vegetations on wind-swept - weakly snowprotected and on sheltered slopes- snowbed sites (Fig. 4). The former group was further divided into three collective clusters, of which the first, the Festuca ovina
Potentilla crantzii group, represents eutrophic grassrich communities with indicators of calcareous soils. The vegetation within this cluster does not clearly correspond to any higher level vegetation unit described earlier, but it seems to be intermediate between the traditional unit Caricetalia curvulae (Braun-Blanquet 1926; Dahl 1957, or Juncion trifidi Nordhagen 1943) and Sesle rietalia coeruleae ( Braun- Blanquet 1926, or Kobresieto-Dryadion Nordhagen 1943). The remaining material in this branch of the dendrogram was divided into two clusters, of which the first cluster contained
LeG PdG DocG AoiAtG SaS WMS
Fig. 4. Dendrogram representing the major divisions of a TWINSP AN classification of the 303 sample plots . The eigenvalues of the divisions are indicated. The community groups of northern Fennoscandia: FovPcrG - Festuca ovina-Potentilla crantzii group, AG Alectoria group, JtCtG - ]uncus trifidus-Cassiope tetragona group, ShG - Salix herbacea group, RgG - Ranunculus glacialis group, SoppG - Saxifraga oppositifolia group. The community groups of Spitsbergen : LeG - Luzula confusa group, PdG - Papaver dahlianum group, DocG - Dryas octopetala group, AbAtG - Alopecurus borealis-Aulacomnium turgidum group, SaS - Sanionia snowbed communities, WMS - Wet moss snowbeds.
Acta Phytogeogr. Suec. 82
12 R. Virtanen & S. Eurola
vegetation on snow-protected sites, to be called the Alectoria group. This corresponds to the traditional higher level vegetation unit Loiseleurieto-A rctostaphylion
( Kalliola 1939, Nordhagen 1943) and to the Arcto
staphylos and Cassiope tetragona- Vaccinium groups of Oksanen & Virtanen (1995). The second cluster included vegetation of snow-protected sites and corresponded to the traditional Juncion trifidi Scandinavicum
(Nordhagen 1943) and the ]uncus trifidus-Cassiope
tetragona group of Oksanen & Virtanen ( 1995). The main cluster with chionophilous-snowbed vegetation was divided into three clusters, of which one is called the Saxifraga oppositifolia group. It is a relatively heterogeneous group, not similar to any higher level vegetation unit described earlier, but it largely comprises a broad group of snow bed communities rich in calciphiles (Gjrerevo11 1956). The snow bed vegetation of siliceous substrates was subsequently divided into two main groups, called Salix herbacea and Ranunculus glacialis groups, recognized also by Oksanen & Virtanen (1995). These differ ecologically from each other in duration of snow cover. In total, the northern Fennoscandian material comprises six community groups including 30 community types or variants.
The ecological relationships of the community types were analysed by means of DCA ordination (Fig. Sa). The first DCA axis seems to be related to snow cover, as the snowbed communities (typical species: Anthelia
juratzkana, Kiaeria starkei, and Polytrichastrum sex
angulare; Fig. 5b) were placed in the left and the ridge heaths were scored in the upper right of the figure (typical species: Alectoria nigricans, Empetrum nigrum ssp. hermaphroditum and Flavocetraria nivalis) . The second
3
Fig. 5a.
2 3
DCA 1 (0.651)
4 5
axis seems to reflect mainly edaphic differentiation along gradient from heaths of siliceous substrate (typical species: Gymnomitrion corallioides) to communities with indicators of calcium carbonate (e.g. Car ex rupestris
and Dryas octopetala) but also to communities on relatively nutrient-rich sites (Anthoxanthum odoratum ssp. alpinum, Poa alpina and Viola biflora) .
Table 2. Preferential (NW Fennoscandia/Spitsbergen) and non-preferential vascular plants given by the first TWINSPAN division. Species with * are encountered exclusively either in the Fennoscandian or the Spitsbergen material.
NW Fennoscandia
Carex bigelowii*
Cassiope hypnoides*
Cassiope tetragona
Festuca ovina*
]uncus trifidus*
Salix herbacea*
Sibbaldia procumbens*
Silene acaulis
Vaccinium vitis-idaea*
Acta Phytogeogr. Suec. 82
Non-preferential
Bistorta vivipara
Dryas octopetala
Spitsbergen
Alopecurus borealis*
Cerastium arcticum
Draba alpina*
Draba subcapitata*
Luzula arctica*
Luzula arcuata ssp. confusa
Oxyria digyna
Papaver dahlianum*
Pedicularis hirsuta
Poa alpigena*
Poa arctica
Salix polaris
Saxifraga cernua
Saxifraga cespitosa
Saxifraga nivalis
Saxifraga oppositifolia
Stellaria longipes*
-2.0
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 13
b
.eru lie
Erne her
. Gym cor
Bet.nan
• Callap .
Ale nig•
Tha ver•
Die fus•
Cas tet. Och fri. Die elo•
Cla coc • •Cia g ra
• •Poljun
.Cet niv
•• cetcuc Bry div
Gy"!con Cas
.hyp
Cet del• Lophozi•
.ste atp
.Die sco
Cetcri
Cla :.m •
.Pol pit ·
vac vit .
Pti cil
Ple.alb .Luz con •Anamin
Con tet• .Cep sp
•sat her Ki� sta •Car big
•Sib pro
Cet ist• Bar flo
• And rup
Tri qui .
san.unc
•Jun tri
•Sal pol •Sit aca
Pol viv•
•Pol alp
•Antodo
•Poaalp
•Hyl ala
. . Fes ovi
. Viobif
•Dry oct
+6.0
Fig. 5 . Ordination diagram of axis 1 against axis 2 using Detrended Correspondence Analysis (DCA) for the TWINSPAN groups (a,
overleaf) in the Fennoscandian material. The centroids (point) are mean sample scores for the ftrst two DCA axes. Circled area indicates S.D. of the scores with respect to the axes. APsT - Antheliajuratzkana-Polytrichastrum sexangulare type, CbT - Carex bigelowii type, CbSpT - Carex bigelowii-Salix polaris type, ChJtTe/ChJtTf - Cassiope hypnoides-Juncus trifidus type, DocCrT - Dryas octopetalaCarex rupestris type, DocCtT - Dryas octopetala-Cassiope tetragona type, ECtTa/ECtTc - Empetrum-Cassiope tetragona type, ECtATb/ECtATc - Empetrum-Cassiope tetragona-Alectoria type, EFnT - Empetrum-Flavocetraria nivalis type, GymnT - Gymnomitrion type, FovDocC - Festuca ovina-Dryas octopetala community, FovDocHC - Festuca ovina-Dryas octopetala-Hylocomium community, FovPcrT - Festuca ovina-Potentilla crantzii type, FovSalpSaC - Festuca ovina-Saussurea alpina-Sanionia community, JtCtTCb -]uncus trifidus-Cassiope tetragona type, Carex bigelowii variant, JtCtTCd - ]uncus trifidus-Cassiope tetragona type, Cetrariella delisei variant, JtCtTe/JtCtTf - ]uncus trifidus-Cassiope tetragona type, typical variants, JtCtTg - ]uncus trifidus-Cassiope tetragona type, graminoid variant, JtCtTm - ]uncus trifidus-Cassiope tetragona type, mossy variant, JtCtTPh - ]uncus trifidus-Cassiope tetragona type, Polytrichum hyperboreum variant, KPC - Koenigia islandica-Phippsia algida community, ShChT - Salix herbacea-Cassiope hypnoides type, ShKiT - Salix herbacea-Kiaeria type, ShKiTCb - Salix herbacea-Kiaeria type, Carex bigelowii variant, SpSacT - Salix polarisSilene acaulis type, SoppRsT - Saxifraga oppositifolia-Ranunculus sulphureus type, TsSaT - Trisetum spicatum-Sanionia type. DCA ordination of the most common species (b) Ale nig - Alectoria nigricans, Ana rnin - Anastrophyllum minutum, And rup - Andreaea rupestris, Ant jur - Anthelia juratzkana, Ant odo - Anthoxanthum odoratum ssp. alpinum, Bar flo - Barbilophozia floerkei, Bet nan -Betula nana, Bry div - Bryocaulon divergens, Cal lap - Calamagrostis lapponica, Car big - Carex bigelowii, Car rup - Carex rupestris, Cas hyp - Cassiope hypnoides, Cep sp - Cephalozia spp. , Cet cri - Cetraria islandica ssp. crispiformis, Cet cue - Flavocetraria cucullata, Cet del - Cetrariella delisei, Cet isl - Cetraria islandica, Cet niv - Flavocetraria nivalis, Cla arb - Cladina arbuscula, Cla gra - Cladonia gracilis, Con tet - Conostomum tetragonum, Die elo - Dicranum elongatum, Die fus - Dicranum fuscescens, Die sco - Dicranum scoparium, Dry oct - Dryas octopetala, Emp her - Empetrum nigrum ssp. hermaphroditum, Fes ovi - Festuca ovina, Gym con -Gymnomitrion concinnatum, Hyl ala - Hylocomium splendens var. alaskanum, Jun tri- ]uncus trifidus, Kia sta - Kiaeria starkei, Lophozi - Lophozia spp. , Luz con - Luzula arcuata ssp. confusa, Phy cae - Phyllodoce caerulea, Ple alb - Pleurocladula albescens, Poa alp - Poa alpina, Pol alp - Polytrichastrum alpinum, Pol jun - Polytrichum juniperinum, Pol pil - Polytrichum pi life rum, Pol sex - Polytrichastrum sexangulare, Pol viv - Bistorta vivipara, Pti cil - Ptilidium ciliare, Sal her - Salix herbacea, Sal pol - Salix polaris, San unc - Sanionia uncinata, Sib pro - Sibbaldia procumbens, Sil aca - Si le ne acaulis, Ste alp - Stereocaulon alpinum, Tha ver - Thamnolia vermicularis, Tri qui - Tritomaria quinquedentata, Vac vit - Vaccinium vitis-idaea, Vio bif - Viola biflora.
Acta Phytogeogr. Suec. 82
14 R. Virtanen & S. Eurola
FovDocC FovDoHC FovPcrT FovSalpSaC JtCtTm
Fig. 6. TWINSPAN division of the Festuca ovina-Potentilla crantzii group. FovDocC - Festuca ovina-Dryas octopetala community, FovDocHC - Festuca ovina-Dryas octopetalaHylocomium community, FovPcrT - Festuca ovina-Potentilla crantzii type, FovSalpSaC - Festuca ovina-Saussurea alpinaSanionia community, JtCtTm - June us trifidus-Cassiope tetragona type, mossy variant.
3.1.1 Festuca ovina-Potentilla crantzii group
Chionophobous-chionophilous steppe-like heath vegeta
tion on moderately calcium carbonate-rich substrate;
Appendix 1, Fig. 6
This community group consists of vegetation characterized by Festuca ovina together with a variable eo-occurrence of indicators of (at least weakly) carbonate-rich substrate (e.g. Dryas octopetala, Potentilla crantzii, Salix
reticulata, Saxifraga spp. and Viola biflora) and grasses such as Anthoxanthum odoratum ssp. alpinum and Poa
alpina. Physiognomically, the vegetation looks like grassy meadows, or maybe better, cold steppes consisting of a large number of vascular plants (more than 50 altogether). This vegetation may represent an ecological counterpart to cold steppes typical of continental mountain regions. These communities develop into arctic dwarf shrub heaths, and in this respect such relations as conveyed by Lloyd et al. (1994) in Alaska might play a certain role also in subcontinental northern Fennoscandia (see also Nordhagen 1943:183).
This group shows affinities with the traditional association F estucetum ovinae alpicolum thoroughly described by N ordhagen (1943) from Sikilsdalen, southern Norway. The cover of lichens, in some communities those of bryophytes, are many times greater in Nordhagen's (1943) material than in ours. On the other hand, lichen cover in
Acta Phytogeogr. Suec. 82
Nordhagen's types, sustained by cattle grazing (the 'Festuca ovina-Potentilla crantzii sosiasjon'), are more comparable to those in our material in which the relatively heavy reindeer trampling has probably reduced the abundance of lichens. In part, this vegetation shows affinities to the Kobresieto-Dryadion (Nordhagen 1943, 1955) due to a relatively rich occurrence of calciphilous species. However, the species composition of the typical Kobresieto-Dryadion communities is somewhat different. This may reflect a situation where the Festucetum
ovinae alpicolum and the Kobresieto-Dryadion communities coexist on mountain slopes where soil properties are heterogeneous which also contributes to large vegetational heterogeneity (Nordhagen 1943: 579-580). In a broader geographical context, Nordhagen (1943) considers the association Festucetum ovinae alpicolum (as part of the Juncetum trifidi) analogous with the Caricetum
curvulae Braun-Blanquet in the Alps, but their ecological or phytosociological relationships have not yet been fully understood ( DierBen 1992).
In the DCA ordination, this group formed a relatively well separated cluster (Fig. Sa). The communities seem to be differentiated in respect to duration of snow cover and nutrient status. Consequently, the first four community clusters can be arranged in the following order with increasing snow cover: FovDocC, FovDocHC, FovPcrT, and FovSalpSaC. Apart from these, cluster JtCtTm seems to be close to the oligotrophic ]uncus trifidus-Cassiope
tetragona heaths placed in the central part of the ordination space. This community might be equally well included in the ]uncus trifidus-Cassiope tetragona group (described below).
In our material, vegetation of the Festuca ovina
Potentilla crantzii group occurs only on the eastern slopes of Mt. Saana, just below the grand vertical mountain walls at an altitude of about 900 m above sea level. Such landscape qualities obviously generate special ecological conditions. The slope is steep and chiefly south-facing, thus it receives much solar radiation. Therefore, soils are relatively dry and warm as compared to the middle oroarctic zone in general. Warmth can last overnight due to stored heat in the soil (oven effect), and warm air masses are uplifted by inversion. Soil substrates are only weakly acidic due to calcareous bedrock and steep topography. Moreover, reindeer grazing may enhance nutrient turnover, as it delays the development of dense dwarf shrub vegetation and promotes the growth of graminoids ( Kalliola 1939: 172-173; Dah1 1957: 106).
Within this community group, five clusters were produced by TWINSPAN. The composition of these clusters did not suggest that they would represent any distinct type of vegetation, rather they might be best regarded as fixed points in a vegetational continuum. Moreover, as the data of this vegetation came from one locality (slope of Mt. Saana), we refrained from describing them all as new
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 15
community types and mainly discuss their species composition and ecological characteristics.
Festuca ovina-Dryas octopetala community (FovDocC)
This community is characterized by the occurrence of indicators of calcium carbonate mixed with patchily growing Festuca ovina and Dryas octopetala. Calciphilous plants are found both among cryptogams (e.g. Cladonia
pocillum and Lescuraea saxicola) and vascular plants (e.g. Carex rupestris and Draba daurica). Most of the species have a low frequency, but as a whole , the species number of the community is high. The species richness of the community may be partly attributable to the presence of many small mosses (e.g. Bryum argenteum and Tortula
norvegica) which occupy mineral soil gaps created by small-scale disturbances. Probably, the open gaps also favour coexistence of many saxifrages.
This community resembles the ' Carex rupestris
Encalypta rhaptocarpa-sosiasjon' typical of calcareous rock ledges in Sikilsdalen, Norway (Nordhagen 1943). The Dryas octopetala-Carex rupestris type, described below, is ecologically related to this community but represents vegetation on more extremely wind-swept sites. The material in this community stems partly from similar exposed rock ledges at the basis of the vertical rock walls of Mt. Saana.
Festuca ovina-Potentilla crantzii type (FovPcrT)
This community has a fairly dense cover of Festuca ovina
giving a meadow-like appearance. The indicators of calcium carbonate are fewer than in the community FovDocC described above, but e.g. Cerastium alpinum, Dryas
octopetala, and Silene acaulis are frequently present. This community is prevalent on sheltered slopes. It resembles the 'Festuca ovina-Potentilla crantzii -sosiasjon' (Nordhagen 1943) which is regarded by Nordhagen (1943) as a secondarily arisen Festuca ovina heath, i.e. a dwarf shrub heath changed to a Festuca ovina dominated community by the grazing of horses. This corresponds to the Potentillo
Festucetum ovinae (Dahl 1957) which is sustained by grazing, while without any grazing, a shrub heath or a shrub heath with herbs would prevail.
For practical purposes (e.g. for needs of vegetation mapping) this vegetation is provisionally described as a new type to be called the Festuca ovina-Potentilla crantzii
type (FovPcrT) with the ecological characteristics of this community group.
Festuca ovina-Dryas octopetala-Hylocomium alaskanum
community (FovDocHC)
This community has a bottom layer with a relatively high total moss cover including Dicranum spp. and Hylocomium
splendens var. alaskanum. The field layer consists of a mixture of plants typical of various habitats. There are species of snow-protected sites (Phyllodoce caerulea,
Salix polaris and Viola biflora) and species typical of mesic sites (Bistorta vivipara and Carex vaginata) and species typical of dry ridges ( Vaccinium vitis-idaea). This community probably represents a transition between dwarf shrub heaths and the meadow-like heath patches characterized by Festuca ovina. Like the community above, this community resembles the 'Festuca ovina-Potentilla
crantzii -sosiasjon' (Nordhagen 1943: 200-201) and the Potentilleto-Festucetum ovinae of Dahl (1957: 106-109) . In Nordhagen's ( 1943) sample data, there is a Hylocomium
variant with a large cover of Hylocomium splendens. In our material, the cover of Hylocomium is not large, but some ecological similarity may exist between these two communities. This somewhat mixed vegetation supports the assertion above that the F estuca ovina heaths show transitions to dwarf shrub heaths without any distinct borders. Natural grazing may be one of the structuring mechanisms within these gradients (Oksanen 1990).
F estuca ovina-Saussurea alpina-Sanionia uncinata com
munity (FovSalpSaC)
This community represents the most chionophilous vegetation in this community group. The characteristic species are Sanionia uncinata and Saussurea alpina. Dwarf shrubs are missing or are very scarce. Otherwise, the field layer is relatively heterogeneous in its composition : some plots have a large cover of Viola biflora while some other plots contain Cerastium alpinum, due to variation in snowduration. V. biflora-characterized communities emerge later from snow than the ones characterized by C. alpinum.
Like the FovPcrT and FovDoc HC described above, this community resembles the 'Festuca ovina-Potentilla
crantzii sos iasjon' of Nordhagen (1943). Especially, the sample plots representing the Polytrichum juniperinum
Cetraria islandica variant (Nordhagen 1943: 200-201) seem to have a relatively similar species composition. Also some of the samples of 'arktische Festuca ovina
Wiesen' in Kalela (1939) from Kalastajansaarento at the N E coast of Fennoscandia are floristically relatively similar, suggesting an affinity to vegetation found normally in the lower oroarctic zone. In our material, the closest community type is the Trisetum spicatum-Sanionia type (see below) that occupies sites with more late-lying snow.
]uncus trifidus-Cassiope tetragona type, mossy variant
(JtCtTm)
This community is characterized by patchily occurring Cassiope tetragona and F estuca ovina. The bottom layer is rich in mosses (Dicranum scoparium and Hylocomium
splendens var. alaskanum). In the ordination, this community cluster is placed relatively close to a community belonging to the ]uncus trifidus-Cassiope tetragona group [the ]uncus trifidus-Cassiope tetragona type, graminoid variant JtCtTg (Fig. Sa)]. This variant has Polytrichum
species as most the prominent in the bottom layer, few
Acta Phytogeogr. Suec. 82
1 6 R. Virtanen & S. Eurola
Dicranum spp. and/or Hylocomium. These two variants can hardly be regarded as s imilar. The 'm' variant community differs from the community types in the ]uncus tri.fidus
Cassiope tetragona group (see below) by the occurrence of e.g. Saxifraga nivalis or more rarely S. cespitosa and S.
oppositifolia, indicating calcareous soil substratum. These communities most l ikely represent an intermediate vegetation between the Festuca ovina-Potentilla crantzii and the ]uncus trifidus-Cassiope tetragona heaths.
3.1.2 Alectoria group
Chionophobous vegetation rich in dwarf-shrubs. Appen
dix 2, Fig. 7
This community group includes vegetation with an abundant occurrence of chionophobous species: Alectoria
nigricans and A. ochroleuca occur constantly, along w ith other l ichens typical of wind-swept sites (e.g. Bryocaulon
divergens, Cetraria nigricans, Flavocetraria nivalis,
Sphaerophorus globosus, and Thamnolia vermicularis)
(Fig. 5b ). Otherwise, the species composition differs quite drast ically among the community clusters. One of the communities is characterized by calciphilous species, while in the other communities, species typical of siliceous substrates are prevalent. The former community resembles the associations included in the Kobresieto-Dryadion
(Nordhagen 1 943) and the latter shows affinit ies to the Loiseleurieto-Arctostaphylion ( Kalliola 1 939) and to the Loiseleurio- Vaccinietea (Daniels 1 994 ). These commu-
DocCrT ECtATb ECtATc GymnT
Fig. 7. TWINSP AN divisions of the Alectoria group. DocCrT -Dryas octopetala-Carex rupestris type, ECtA Tb/ECtAc -Empetrum- Cassiope tetragona-Alectoria type, GymnT -Gymnomitrion type.
Acta Phytogeogr. Suec. 82
nities differ, however, from the Loiseleurieto-Arctosta
phylion by the total absence of Arctostaphylos alpina and Loiseleuria procumbens. This is probably due to the fact that our plots lie above the al t itudinal l imit for common occurrence of these species (wide-spread in the lower oroarctic zone). The four types of this group can be described as follows:
Dryas octopetala-Carex rupestris type (DocCrT)
A dist inct community identified by TWINSP AN consists of s ix plots with calciphilous plants and a bottom layer w ith indicators of chionophobous condit ions. Dryas
octopetala dominates and another xeric calcicole species, Car ex rupestris, is common. The vegetation of this type is patchy due to frost heaving, wind abrasion and accumulat ion of weathered mater ial. Also rare species, such as Arnica angustifolia ssp. alpina, Carex glacialis and among mosses e.g. Campylophyllum halleri, Hypnum bambergeri
and Schistidium tenerum were observed. These habitats at Kilpisjarvi are typically found on the steep slopes of Mt. Saana and on wind-exposed s ites on the dolomite peak of Mt. Guonjarvam. This type appears to be restr icted to a few topographically rugged localities which are less accessible for reindeer. On these s ites, Dryas octopetala
often forms a nearly closed cover. This community corresponds to some sample plots in
Nordhagen's ( 1 936) 'artenarme Dryas-Carex rupestris
Soziation', and his (1955) Dryadetum octopetalae rich in Carex rupestris, Bringer's ( 1 96 1 ) Epibryo-Dryadetum
(Dryas-Carex rupestris-fazies). It can also be regarded as the middle oroarctic counterpart of Kalliola's ( 1 939)
'Dryas-Alectoria-Flavocetraria nivalis-Soziat ion', and Kalela's ( 1 939) ' Carex rupestris-Wiese ' . On Spitsbergen, the corresponding noda are the Rupestri-Dryadetum
( R�nning 1 965) and the Carici rupestris-Dryadetum
( Hartmann 1 980), with as characteristic species Draba
subcapitata and Schistidium apocarpum. Our data from Spitsbergen do not contain sample plots which clearly represent this type of vegetation .
Empetrum-Cassiope tetragona-Alectoria type (ECtA Tb,
ECtATc)
These two community clusters, ECtATb and ECtA Tc, show aff init ies to the Cassiope tetragona-Cetraria
n ivalis type (CtCnT), the Vaccinium-Alectoria type (V AT) and the Empetrum-Phyllodoce-Alectoria (EPAT) of Oksanen & V irtanen ( 1 995) . One of them ( ECtATb) can be regarded as an intermediate type between the Cassiope tetragona-Flavocetraria n ivalis type and the Vaccinium-Alectoria type, while the other ( ECtATc) resembles the Empetrum-Phyllodoce-Alectoria type, except for the scanty occurrence of Phyllodoce caerulea.
The three community types, CtCnT, EPAT and VAT, form a relatively d iffuse pattern of variat ion where local condit ions and stochastic processes influence the
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 17
abundance rela tionships between er icaceous plants. Vaccinium vitis-idaea seems to thrive best in contact w ith pure rock, probably because its strong vegetative reproduction makes it sensitive to cryoperturbation. Empetrum nigrum ssp. hermaphroditum reproduces also vegetat ively (Soyr inki 1939) which makes it sensitive to uprooting in s ites w ith intense cryoperturbation. Phyllodoce caerulea has only weak adventitious roots, and it is thus res is tant to cryoperturba tion (Soyr ink i 1939 ; Dahl 1957) . The same appears to apply to C.
tetragona (Warming 1908) which, moreover, is better adapte d to the m iddle arct ic and m iddle oroarctic conditions , and thus tends to replace P. caerulea, if present in the spec ies pool. It seems thus reasonable to regar d the Cassiope tetragona-Cetraria nivalis type and the Empetrum-Phyllodoce-Alectoria type as local var iants of a s ingle type; the latter variant being ma inly encountered outs ide the range of C. tetragona. The Vaccinium
Alectoria type, in turn, occurs locally and changes gradually into the other types so that it is impractical to dis tinguish it as a type of its own. We thus propose that these three vegetation noda, along w ith the clusters ECtA Tb and ECtA Tc in our material, w ill be regarded as var iants of a more inclusive community type , to be referred to as the Empetrum-Cassiope tetragona
Alectoria type ( ECtAT). Closest counterparts are de-
0.235
scr ibed from Greenland ( Cassiopetetum tetragonae;
Bocher 1933; Daniels 1982).
Gymnomitrion type (GymnT)
This community is characterized by chionophobous species that are common in the community group. However, now Gymnomitrion corallioides occupies relatively large areas in the w ind-exposed centres of elevated polygons, while the hollows are rich in Dicranum and Polytrichum
moss species. The hollows are also occupied by vascular plants demanding protection from strong abrasive w inds (e.g. Betula nana, Cassiope tetragona, Empetrum nigrum
ssp . hermaphroditum and Vaccinium vitis-idaea) . This community prevails on mountain top plateaux where soil conditions are suitable for the development of polygons. In these habitats, slow-rate cryoperturbation, relatively oceanic climate ( Haapasaari 1988) and/or reindeer trampling (Nordhagen 1943) seem to maintain frost boils colonizable for hepatics . These frost boils seem to favour especially G. corallioides. When the polygons are more intensely frost-heaved, the plant cover becomes extremely sparse. On the other hand, when they are stable, then w in d-har dy l ichens, such as A lectoria nigricans,
A. ochroleuca, and Flavocetraria nivalis, occur with a high cover ( if not decimated by reindeer). This type seems to represent a parallel type for the ECtA T that prevails on
ECtTa EFnT ECtTc JtCtTCb JtCtTe JtCtTf JtCtTg JtCtTPh
Fig. 8 . TWINSPAN divisions of the ]uncus trifidus-Cassiope tetragona group. ECtTa/ECtTc - Empetrum-Cassiope tetragona type, EFnT - Empetrum-Flavocetraria nivalis type, JtCtTCb - ]uncus trifidus-Cassiope tetragona type, Carex bigelowii variant, JtCtTe/JtCtTf - ]uncus trifidus-Cassiope tetragona type, typical variant, JtCtTg - ]uncus trifidus-Cassiope tetragona type, graminoid variant, JtCtTPh - ]uncus trifidus-Cassiope tetragona type, Polytrichum hyperboreum variant.
Acta Phytogeogr. Suec. 82
18 R. Virtanen & S. Eurola
more stable ridge s ites. The frequent and relatively intense cryoactivity counteracts leaching and enables the occurrence of calciphilous plants, e.g. Dryas octopetala,
in the centres of polygons (see also Jonasson & SkOld 1983) .
3.1.3 ]uncus trifidus-Cassiope tetragona group
Chionophilous vegetation rich in graminoids and/or dwarf
shrubs; Appendix 3, Fig. 8
The core of the materia l in this community group cons ists of TWINSP AN clusters with vegetat ion corresponding to the tradit ional alliance Juncion trifidi scandi
navicum (Nordhagen 1943) and the ]uncus trifidus
Cassiope tetragona group in Oksanen & Virtanen ( 199S) . In the ordination space, most of the types assigned to th is group take an interme diate pos it ion between the ch ionophobous heath types (the Alectoria group) and Festuca ovina-Potentilla crantzii heaths (the Festuca
ovina-Potentilla crantzii group), while clusters EFnT and ECtTc overlap with the chionophobous heaths (Fig. Sa) . These two latter community clusters are r ich in dwarf shrubs, and they also have a species composition characterized by chionophobous species and thus resemb le the vegetation types in the Cassiope tetragona
Vaccinium group of Oksanen & Virtanen (199S). However, the group mainly represents sl ightly-moderately ch ionophilous middle oroarctic heath vegetation in accordance with the ]uncus trifidus-Cassiope tetragona
group in Oksanen & Virtanen (199S) .
Empetrum-Cassiope tetragona type (ECtTa, ECtTc)
The pair of clusters (ECtTa and ECtTc) are characterized by Cassiope tetragona occurring with a relatively high cover. The other of them (ECtTc) has Empetrum nigrum
ssp . hermaphroditum as eo-dominant, while among l ichens ch ionophobous Sphaerophorus globosus and Thamnolia vermicularis are typical . Among mosses Aulacomnium turgidum, Hylocomium splendens var. alaskanum, and Racomitrium lanuginosum are relatively constant and g ive some oceanic character . This community is chiefly encountered on westerly slopes of the mountains at Kilpisjarvi exposed to marit ime north Atlant ic winds (Fig. 9). The cryptogam layer of the other cluster (ECtTa) is r ich in l ichens, but also Hylocomium splendens
var . alaskanum is relatively abundant. Festuca ovina occurs scattered and ]uncus trifidus is totally absent. The c lusters ECtTa and ECtTc are not very close to each other in the ordination (Fig. Sa), which suggests an ecological differentiation: ECtTc takes a quite extreme position near the types of the Alectoria group. However, the community is not confmed to the most wind-exposed s ites, but rather occupies concave slopes retaining a continuous
Acta Phytogeogr. Suec. 82
snow cover at winter t ime . In the ordination ECtTa is placed among the luncus trifidus-Cassiope tetragona type suggesting that the dwarf shrub heaths and the vegetation of the gram ino id-rich vegetation of Juncion trifidi
scandinavicum are intermingled. The community clusters ECtTa and ECtTc do not
clearly correspond to any of the types of Oksanen & Virtanen (199S). The Cassiope tetragona-Dicranum
fuscescens association of Nordhagen (19SS) is s imilar, except in our material Diapensia lapponica is m issing, Dicranum fuscescens and Flavocetraria nivalis occur in lower and Salix herbacea in h igher abundance than in Nordhagen ' s material. The closest community types are the continental ]uncus trifidus-Cassiope tetragona type and the oceanic Salix herbacea-Empetrum type, that have less Cassiope tetragona. The occurrence of such mosses as Racomitrium lanuginosum creates affinities to the oceanic Empetrum heaths which in the middle oroarctic zone of oceanic sectors develop into a vegetation of the Salix
herbacea-Empetrum type (Oksanen & Virtanen 199S). On these grounds we suggest that these community c lusters collectively represent a new transitional subcontinental-suboceanic type, to be called the Empetrum-Cassiope
tetragona type (ECtT). Relatively s imilar counterparts are reported from West Greenland (Bocher 19S4, 1963; Daniels 1982 : heaths r ich in Cassiope tetragona).
Empetrum-Flavocetraria nivalis type (EFnT)
This community c luster represents chionophobous heath vegetation, as indicated by the occurrence of Alectoria
spec ies together with Flavocetraria nivalis. Betula nana
is creeping over ground and occurs with a relatively high cover. Th is community corresponds rather well to the Empetrum-Cetraria nivalis type of Oksanen & Virtanen (199 S). However, the occurrence of Racom itrium
lanuginosum suggests that the communit ies at Kilpisjarvi show intermediate features between the oceanic Salix
herbacea-Ochrolechia type and the subcont inental Empetrum-Cetraria nivalis type (Oksanen & Virtanen 199S).
]uncus trifidus-Cassiope tetragona type (JtCtT);
mossy, Carex bigelowii, typical (in two clusters),
graminoid, Polytrichum hyperboreum, and Cetrariella
delisei variants
The community clusters JtCtTm, JtCtTCb, JtCte, JtCtTf, JtCtTg, JtCtTPh and JtCtTCd lie in the centre of the ordination space (Fig. Sa), together, they seem to correspond to the ]uncus trifidus-Cassiope tetragona type of Oksanen & Virtanen (199S). These communities share largely the same diagnostic features: i.e. the f ie ld layer dominated by ]uncus trifidus, alone or together with Cassiope tetragona, Festuca ovina, and/or Salix herbacea.
The bottom layer is r ich in Cetraria ericetorum, C.
islandica, and/or Flavocetraria nivalis. The clusters over-
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 19
Fig. 9. Middle oroarctic Empetrum-Cassiope tetragona heath vegetation. Mt. Jehkats W-slope 900 m. In the centre Racomitrium lanuginosum fairly abundant. June 1 988. (Photo: Risto Virtanen.)
lap with each other showing some ecological variation with respect to the fust two ordinat ion axes. Cluster JtCtTg is more distant from the other clusters and are placed relatively close to eutrophic Festuca ovina
Potentilla crantzii heaths (the Festuca ovina-Potentilla
crantzii group). We are apt to retain a collective classificat ion and use the separate community clusters mainly for the ecological characterization.
]uncus trifidus-Cassiope tetragona type, Carex bigelowii
variant (JtCtTCb)
This community is characterized by patchily occurring Cassiope tetragona and ]uncus trifidus, occasionally also Empetrum, while Carex bigelowii is found more constantly with a cover of 2-3%. In the bottom layer characteristic l ichens include Cetraria ericetorum, Cladina arbus
cula (mainly C. arbuscula ssp. mitis), and Stereocaulon
spp. A typical hepatic species is Anastrophyllum minutum.
In the ordination, this community cluster is relat ively close to the Empetrum-Flavocetraria nivalis type (EFnT) and could represent an intermediate community between
the dwarf shrub heaths and the grarninoid-rich communit ies of the ]uncus trifidus-Cassiope tetragona type (Oksanen & V irtanen 1995). The intermediate community may represent a successional stage developed under influence of re indeer trampling, as suggested by a relatively high cover of Carex bigelowii as well as by rich eooccurrence of small hepatics mixed within a thinned l ichen cover. This community is referred to as the Carex
bigelowii variant of the ]uncus trifidus-Cassiope tetragona
type.
]uncus trifidus-Cassiope tetragona type, typical vari
ant (JtCtTe, JtCtTf)
These two community clusters produced by TWINSP AN are relatively s im ilar in their species compositions . Both clusters have Salix herbacea with relatively h igh cover values, with at least some Cassiope tetragona (Fig . 1 0) . One of the clusters, JtCtTe, is rich in ]uncus trifidus and the other, JtCtTf, r ich in Festuca ovina . These communit ies resemble the ]uncus trifidus-Cassiope tetragona type in Oksanen & Virtanen ( 1995). However, none of the
Acta Phytogeogr. Suec. 82
20 R. Virtanen & S. Eurola
Fig. 1 0. ]uncus trifidus-Cassiope tetragona type heath vegetation. Mt. Guonjarvam. Alt. 960 m. July 1989. (Photo: Risto Virtanen.)
variants described there is conspicuously simi lar in species abundance re lationships. These two communities show more c learly affinities to the northern and oceanic counterpart of Juncion trifidi, i.e. the Salix herbacea
Empetrum type (Oksanen & Virtanen 1995). On the other hand, the luncus trifidus-rich community (JtCtTe) is much like the ']uncus trifidus-grashei ' described by Nordhagen (1943: 219-220) from Rastigaissa at interior Finnmark. Th is suggests that these two c lusters may represent the typical, but local ly variable, elements of ch ionophilous vegetation on subcontinental mountains of northwestern Fennoscandia.
]uncus tri.fidus-Cassiope tetragona type, graminoid
variant (JtCtTg)
This community has a relat ively sparse field layer with about equally abundant Festuca ovina and luncus trifidus.
Evergreen dwarf shrubs are only sporadical ly present. In the cryptogam layer, Polytrichaceae mosses (Polytri
chastrum alpinum and Polytrichum piliferum) are relat ively abundant. In Oksanen & Virtanen (1995), the c losest counterpart is the Festuca ovina variant of the ]uncus
trifidus-Cassiope tetragona type. However, scattered Erigeron uniflorus and Minuartia biflora indicate a cer-
Acta Phytogeogr. Suec. 82
tain influence of calc ium carbonate. In the ordination (Fig. 15a), this community is about intermediate between the clusters of the Festuca ovina-Potentilla crantzii group and the other clusters of this group. This community is also p laced c lose to c luster JtCtTm in the ordinat ion but has a lower cover of Cassiope tetragona. This community cluster could be regarded as a grarninoid variant of the JtCtT between the typical variants of the type and the Festuca ovina-Potentilla crantzii group.
]uncus tri.fidus-Cassiope tetragona type, Polytrichum
hyperboreum variant (JtCtT Ph)
This community is re latively open and characterized by Cassiope tetragona and ]uncus trifidus growing in spaced patches. The cryptogam layer is rich in Cetrariella delisei,
Cetraria ericetorum, and C. islandica ssp. crispiformis,
Polytrichum hyperboreum, often encrusted with Ochro
lechiafrigida (mean cover 25 %). In its species composition this community resembles fairly well the Trientalis
variant of the ]uncus trifidus-Cassiope tetragona type in Oksanen & Virtanen (1995). However, in our material Trientalis europaea is absent, and chionophobous l ichens such as Alectoria nigricans and A. ochroleuca occur w ith lower covers than in the Trientalis variant. The sample
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 21
ShKIT ShChT ShKITCb CbT ChJtT C hJtT CbSpT JtCtTCd TsSaT
Fig. 1 1 . TWINSPAN divisions of the Salix herbacea group. CbT - Carex bigelowii type, CbSpT - Carex bigelowii-Salix polaris type, ChJtTe/ChJtTf - Cassiope hypnoides-Juncus trifidus type, JtCtTCd - ]uncus trifidus-Cassiope tetragona type, Cetrariella delisei variant, ShChT - Salix herbacea-Cassiope hypnoides type, ShKiT - Salix herbacea-Kiaeria type, ShKiTCb - Salix herbacea-Kiaeria type, Carex bigelowii variant, TsSaT - Trisetum spicatum-Sanionia type.
plots assigned to this cluster were encountered on sloping sites with gravelly soil where reindeer trampling is intense. The relatively high cover of Polytrichum
hyperboreum is regarded as an indication of reindeer trampling (Oksanen & Virtanen 1995). Thus, this variant community obviously represents a trampled stage of the }uncus trifidus-Cassiope tetragona type on relatively high altitudes and on nutrient-poor hill slopes.
]uncus trifidus-Cassiope tetragona type, Cetrariella
delisei variant (JtCtT Cd)
This cluster characterized by Cassiope tetragona with Cetrariella delisei was assigned to the group of moderate snowbed communities . However, in its species composition this community resembles more closely the vegetation of the }uncus trifidus-Cassiope tetragona group than snowbeds. The high cover of Cetrariella delisei may be related to its tolerance to freezing in solid ice (Dahl 1957; Oksanen & Virtanen 1995) . Such ice formation is likely to occur in relatively level habitats, in which this community was encountered on Mt. Guonjarvarri. The formation of ice lenses may explain the sparse field layer. Cassiope
tetragona itself can elevate shoots several centimetres above the ground, and thus partially avoid freezing damage. The freezing in solid ice is probably an important ecological factor, but as yet little known (cf. Oksanen & Virtanen 1995). Due to the occurrence of Cetrariella
delisei this type is described as the Cetrariella delisei
variant of the }uncus trifidus-Cassiope tetragona type.
3.1.4 Salix herbacea group
Moderate-late snowbed vegetation; Appendix 4, Fig. 1 1
This group comprises a series of snowbed communities apparently from a wide array of ecological conditions related to the length of a snow-free period. Three of the community clusters, ShK.iT, ShChT, and ShK.iTCb, are characterized by Salix herbacea and Cassiope hypnoides,
corresponding to the traditional Cassiopeto-Salicion
herbaceae (Nordhagen 1943) and the Salix herbacea
Kiaeria group in Oksanen & Virtanen (1995). These communities seem to be differentiated regarding the length of the snow-free period and moisture conditions. One of the remaining clusters, CbT, includes snowbeds dominated by Carex bigelowii, and thus corresponds to the vegetation found in the traditional group Nardeto-Caricion
rigidae (Nordhagen 1943). Some of the communities, ChJtTe and ChJtTf, seem to change gradually towards the upper oroarctic vegetation resembling the Luzuleto
Cesietum (Dahl 1957: 169-176) or the Luzula confusa
group in Oksanen & Virtanen (1995) . The positive branch of the TWINSP AN tree includes two clusters where the communities have many indicators of nutrient-rich site conditions. The first of them, cluster TsSaT, might be best characterized as eutrophic snowbed vegetation . This vegetation shows affinity with the Ranunculeto-Oxyrion
(Nordhagen 1943) or with the Ranunculus glacialis group in Oksanen & Virtanen (1995). The second cluster, CbSpT,
Acta Phytogeogr. Suec. 82
22 R. Virtanen & S. Eurola
resembles to a large degree the herb-rich vegetation of Carex bigelowii-Salix polaris type (Oksanen & Virtanen 1 995). The vegetation types of this group can be described as follows :
Salix herbacea-Kiaeria type (ShKiT)
This community is characterized by Salix herbacea and Kiaeria starkei occurring with high cover. Gnaphalium
supinum and Sibbaldia procumbens are regular constituents with low cover. The cryptogam layer is rich in hepatics (Barbilophozia subgenus Orthocaulis, Lophozia
spp.) and snow bed mosses (e.g. Conostomum tetragonum).
This cluster occurs at the relatively extreme end of the snow gradient (Fig. Sa). This community cluster corresponds to the 'Salix herbacea-Kiaeria starkei-Polytrichum
sexangulare-sosiasjon ' of Nordhagen ( 1 943) and the Salix
herbacea-Kiaeria starkei-sociation of Gjrerevoll ( 1 956).
This community is similar to the Salix herbacea-Kiaeria
type described in Oksanen & Virtanen ( 1 995).
Salix herbacea-Cassiope hypnoides type (ShChT)
This type differs from the Salix herbacea-Kiaeria type above by having a relatively high coverage of Cassiope
hypnoides (almost lacking in the Salix herbacea-Kiaeria
type). The bottom layer is richer in lichens (Cetraria
ericetorum, C. islandica ssp. crispiformis, and Cladonia
coccifera), while Kiaeria starkei is almost absent, and Polytrichum spp. are more common than in the Salix
herbacea-Kiaeria type. The Salix herbacea-Cassiope
hypnoides type prevails on sites with a longer snow-free period than on the sites of the Salix herbacea-Kiaeria type. The Salix herbacea-Cassiope hypnoides type corresponds well to some samples of 'moselyngsnOleier ' ( Cassiopetetum
hypnoidis) in Nordhagen ( 1 943 : 262) and the Salix herbacea
Cassiope hypnoides type in Oksanen & Virtanen ( 1 995). It also resembles the Cassiope hypnoides-Antheliajuratzkana
Gymnomitrion varians-sociation in Gjrerevoll ( 1 956), but the cover values of the small hepatics are remarkably lower than in Gjrerevoll 's material.
Salix herbacea-Kiaeria type, Carex bigelowii variant
(ShKiTCb)
This community cluster is dominated by Salix herbacea,
and also Carex bigelowii is relatively abundant, too. This differs from the Salix herbacea-Cassiope hypnoides type in having a low coverage of Cassiope hypnoides. The cryptogam layer is characterized by a thin hepatic layer (total cover 1 5-20 % ) . The typical species include Anastrophyllum minutum, Gymnomitrion apiculatum, G. concin
natum and Lophozia spp. A typical lichen is Cetrariella
delisei, but its cover is low (about 2 % ). It seems that the community is related to Salix herbacea snowbeds (association Salicetum herbaceae Gjrerevoll 1 956: 1 06, the
Acta Phytogeogr. Suec. 82
'mosrik Salix herbacea-sosiasjon ' Nordhagen 1 943: 266),
but no samples with a conspicuously similar community composition were found. Indeed, this may represent an intermediate community between the Salix herbacea and Carex bigelowii snowbeds. Thus, we consider the type as a Carex bigelowii variant of the Salix herbacea-Kiaeria
type, where the abundance of Carex bigelowii indicates moister site conditions than in the sites of the main type.
Carex bigelowii type (CbT)
This community is characterized by a rather uniform cover of Carex bigelowii (mean cover about 1 3 %) ; Salix
herbacea has a relatively low cover giving a more meadowlike appearance. Other characteristic species in the field layer are Bistorta vivipara and Cassiope hypnoides. In the cryptogam layer Anthelia juratzkana and Conostomum
tetragonum are frequent indicating true snowbed conditions. This type is often encountered in sites periodically irrigated by melt water of snow fields. This vegetation corresponds to the 'Carex rigida -Ass. ' (Nordhagen 1 928),
the ' Carex rigida-Wiese ' ( Kalliola 1 939) and the ' Carex
rigida-Lachenalii-sosiasjon' of Nordhagen ( 1 943 : 250-
260). In Gjrerevoll 's ( 1 956) material, the closest counterparts are found among Carex bigelowii -sociations, but none of his samples resembles ours. This type was not encountered in the data of Oksanen & Virtanen ( 1 995) . A reason may be that the Carex bigelowii snowbeds prevail on relatively level ground in mountain valley bottoms and usually they are not found in sloping ridge-depression topographic transects.
Cassiope hypnoides-Juncus trifidus type (ChJtTe,
ChJtTf)
There is a pair of clusters, ChJtTe and ChJtTf, characterized by a relatively high abundance of Cassiope hypnoides,
Luzula arcuata ssp. confusa and/or ]uncus trifidus in the field layer, while the cryptogam layer is covered chiefly by Gymnomitrion spp. Among the lichens Cetrariella
delisei is relatively abundant. In our material, the samples are from relatively level plateaux with polygon fields, chiefly on Mt. Gahpperus. The polygons are more or less active which may increase the vegetational heterogeneity. Overall, these communities resemble much the Cassiope
hypnoides-Juncus trifidus type in Oksanen & Virtanen ( 1 995). The other community, ChJtTe, resembles in its species composition the 'Ranunculus glacialis-Luzula
confusa-Anthelia-Cesia-sosiasjon' of Nordhagen ( 1 943 :
27 1 -278). The abundance of R. glacialis is lower in our material than in Nordhagen 's. The other community, ChJtTf, resembles the Luzuleto-Cesietum ( Dahl 1 957),
but it has a conspicusously higher cover of Cassiope
hypnoides (almost lacking in Dahl 's material) and lesser Polytrichastrum sexangulare than is found in Dahl ' s descriptions. The variations in the abundance relationships of species may reflect a patchy plant cover typical at
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 23
altitudes of about 1 000- 1 100 metres where the middle
oroarctic zone is connected to the upper oroarctic zone.
Carex bigelowii-Salix polaris type (CbSpT)
This community is characterized by Carex bigelowii,
Festuca ovina, and Salix herbacea which are frequently mixed with indicators of calcareous substrate (e.g. Silene
acaulis and Salix polaris). The field layer includes a
conspicuously large number of arctic-alpine herbs (e.g.
Antennaria canescens, A. porsildii, Cerastium arcticum,
Erigeron uniflorus, and Ranunculus n ivalis ) . The
cryptogam layer is rich in lichens, but only Cladina
arbuscula ssp. mitis, has a relatively high cover. Cetra
riella delisei and Cladonia uncialis are characteristic
species. The cover of lichens is obviously decimated by
reindeer grazing. In the ordination (Fig. Sa), the commu
nity is close to the heath-like Salix herbacea snowbeds (ShChT, ShKiTCb) . This community has some affinity
with the Cassiope tetragona-Dryas heaths described as the Cassiopetum tetragonae dryadetosum by Nordhagen
( 1 9SS) . This community also resembles some of the
sample plots of the Polygoneto-Salicetum herbaceae
(Dahl 1 9S7 : 1 78- 1 88) . Dahl ( 1 9S7) describes this veg
etation type as eutrophic, seasonally wet and late
snowbed, frequently with signs of solifluction. This
characterization is fairly similar to the description of a
species-rich type described by Oksanen & Virtanen
( 1 99S) near the limit of continuous plant cover: The
Carex bigelowii-Salix polaris type was characterized as
'alpine garden ' owing to soil conditions enriched by
nutrient supply from (periodic) surface water flush or
groundwater. Aesthetically attractive communities can
be found at such places. The community cluster can be
regarded as a well-drained and relatively lichen-rich
(continental) variant of the Carex bigelowii-Salix pola
ris type.
Trisetum spicatum-Sanionia type (TsSaT)
This community cluster represents meadow-like snow bed
vegetation with herbs (Ranunculus acris ssp. pumila, R.
Fig. 1 2. TWINSPAN divisions of the Ranunculus glacialis group (a) APsT -Anthelia juratzkana-Polytrichastrum sexangulare type, KPC - Koenigia islandica-Phippsia algida community, and Saxifraga oppositifolia group (b) DocCtT - Dryas octopetala-Cassiope tetragona type , SpSacT - Salix polaris-Silene acaulis type, SoppRsT - Saxifraga oppositifolia-Ranunculus sulphureus type.
APsT
nivalis, and Sibbaldia procumbens) and graminoids (Car ex
lachenalii and Trisetum spicatum) . The abundance of C. lachenalii is high compared to that of C. bigelowii. In the
bottom layer Sanionia uncinata is abundant. In the ordi
nation (Fig. Sa) it has a position close to the Festuca
ovina-Potentilla crantzii heaths. As compared to Gjrere
vol l ' s ( 1 9S6) classification, this community falls between
the alliances Deschampsio-Anthoxanthion and Ranunculo
Anthoxanthion, and no similar sociation can be found in
his material. Rather, this community can be regarded as
similar to the Trisetum spicatum-Sanionia type in Oksanen
& Virtanen ( 1 99S).
3.1.5 Ranunculus glacialis group
Oligotrophic late snowbeds; Appendix 5, Fig. 12a
This group embraces a pair of community types repre
senting separate higher level vegetation units. One of the
communities, cluster APsT, is a cryptogam-dominated
snowbed which could be included in the traditional alli
ance Polytrichion norvegici (Gjrerevoll 1 9S6) or Ranun
culus glacial is group of Oksanen & Virtanen ( 1 99S). The
other community, cluster KPC, resembles the meadow
like snowbed communities in the alliance Ranunculeto
Oxyrion ofNordhagen ( 1 943) or the Oppositifolio-Oxyrion
of Gjrerevoll ( 1 9S6).
Anthelia juratzkana-Polytrichastrum sexangulare type
(APsT)
This community is dominated by cryptogams, of which
Anthelia juratzkana and Polytrichastrum sexangulare are
the most prominent species. Vascular plants include Gnaphalium supinum and Ranunculus nivalis (more rarely
R. glacialis), and e.g. Salix herbacea is absent. This
community is encountered near the latest snow fields
emerging from snow in late July or August and changes
into the less extreme snowbed communities where also
vascular plants, e .g . Oxyria digyna and Ranunculus
b)
0.3 1 6
KPC
SpSacT SoppRsT DocCtT
Acta Phytogeogr. Suec. 82
24 R. Virtanen & S. Eurola
glacialis, become more abundant. The community cluster
resembles the association Ranunculetum glacialis in Gj rerevoll ( 1 956 : 1 36) or the Ranunculus glacialis
Gymnomitrion type of Oksanen & Virtanen ( 1 995). How
ever, this cluster represents the most extreme snowbeds
that are virtually devoid of vascular plants and is thus
described as the Anthelia juratzkana-Polytrichastrum
sexangulare type, also found at relatively high altitudes in
the oceanic sectors of northern Norway (Virtanen et al.
unpubl. data).
Koenigia islandica-Phippsia algida community (KPC)
This community cluster represents a distinct community
characterized by a hydrophilous moss Wamstorfia exan
nulata growing in mats on which e.g. Saxifraga stellaris
frequently flourishes. Anthelia juratzkana and Pleuro
cladula albescens are characteristic hepatics. This com
munity resembles Gjrerevoll ' s ( 1 956 : 356) Phippsia
algida-sociation, but the coverage of herbs in the field
layer is lower in his material. Due to scanty material (only
two sample plots in this cluster), our characterization has
to be regarded as tentative.
3.1.6 Saxifraga oppositifolia group
Moderate-late snowbeds on calcareous substrates;
Appendix 6, Fig. 1 2b
This community group represents vegetation on calcare
ous soils along a gradient from the sites with moderate
snow cover to the sites with late snow. In the TWINSP AN
analysis, three community clusters were recognized. One
of the community clusters, DocCtT, is placed relatively
close to the Dryas octopetala-Carex rupestris type (Fig.
5a). The two remaining community clusters, SpSacT and SoppRsT, are noted among the sites with late-lying snow.
In terms of species composition, these snowbed commu
nities are related to Gjrerevoll ' s ( 1 956: table 59) alliance
Oppositifolio-Oxyrion.
Dryas octopetala-Cassiope tetragona type (DocCtT)
This community is clearly dominated by Dryas octopetala
and Cassiope tetragona. In smaller amounts, but con
stantly, Salix polaris, S. reticulata, Saussurea alpina
and Thalictrum alpinum occur. Cetraria ericetorum and
C. islandica are relatively abundant while Mnium blyttii
is one example of many calciphilous mosses. This com
munity resembles the association Cassiopetum tetragonae
dryadetosum of Nordhagen ( 1 955), but in Nordhagen ' s
sample material Hylocomium splendens dominates the
ground layer (not at all in our material ) . This community
can be interpreted as a middle oroarctic counterpart of
Bringer' s ( 1 96 1 ) Tetragono-Dryadetum alectorietosum
described from northern Sweden. The counterpart de-
Acta Phytogeogr. Suec. 82
scribed by R�nning ( 1 965) from Spitsbergen is the
Tetragono-Dryadetum. R�nning considers this type simi
lar to Nordhagen' s Cassiopetetum tetragonae drya
detosum. In the numerical TWINSP AN classification,
the vegetation of this group of northern Fennoscandia
and Spitsbergen is well differentiated. The difference is
distinct in the cryptogam layer: on Spitsbergen, mosses
such as Aulacomnium turgidum, Hylocomium splendens
var. alaskanum, Oncophorus wahlenbergii, Sanionia
uncinata and Tomentypnum nitens are frequent and of
ten also abundant.
Salix polaris-Silene acaulis type (SpSacT)
In this community, the most abundant species are Salix
polaris and Silene acaulis. Other characteristic species
include Cerastium arcticum, Oxyria digyna and Saxifraga
cemua. In the field layer, there are small herb species that
do not typically occur in the latest snow beds (e.g. Anten
naria porsildii, Erigeron uniflorus and Gnaphalium
supinum) . The cryptogam layer is rich in moss and lichen
species, and none of the species has a dominant position.
The closest counterpart in Gjrerevoll ' s material is found
in the association Oppositifolietum. Some sample plots
from Swedish Tome Lappmark (Gjrerevoll 1 956: table
59, column 8) are rather similar, but such species as
Sauteria alpina are missing in our material. This commu
nity, overall, does not conform with the Oppositifolietum
of Gjrerevoll ( 1 956). It thus appears that this community
could then be described as a new vegetation type in order
to characterize the vegetation on moderate snowbed sites
on calcareous substrates. This type of vegetation occurs in
concave terrains in typical snow accumulation sites, but at
higher altitudes also on relatively convex mountain slopes
(e.g. on the southern slopes of Mt. Pihkahistama, northern Norway, own observations).
Saxifraga oppositifolia-Ranunculus sulphureus type
(SoppRsT)
At first sight, this vegetation may give an impression of
a barren ground devoid of any higher plants. Indeed, the
field layer is poor, but after close examination many
species can be found (Fig . 1 3) . The most characteristic
species are Equisetum variegatum, Ranunculus sulphu
reus, and Saxifraga oppositifolia. The moss cover is not
thick, but many small acrocarpic species occur and may
reach covers of a few percentages (e.g. Distichium
capillaceum, Fissidens osmundoides, Meesia uliginosa
var. arctica, Tortella fragilis and Tortula norvegica) .
Among the mosses there may be some rare species (e.g.
Tayloria froelichiana) . The calcicolous lichen Solorina
bispora is rather constant . This community is clearly
calcitrophic and usually found in terrain with calcareous
outcrops. The closest counterparts in Gjrerevoll ' s ( 1 956)
descriptions are found among the associations Oppositi
folietum and Ranunculetum nivalis. However, the units
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 25
Fig. 1 3 . A snowbed of Saxifraga oppositifolia-Ranunculus sulphureus type. Mt. Guonjarvarri . Alt. 950 m. July 1 989. (Photo: Risto Virtanen.)
of Gjrerevoll are relatively narrow. It seems that this
cluster can be described as a new type. This type, to be
called the Saxifraga oppositifolia-Ranunuculus sulphu
reus type, is relatively broad, containing both snowbeds
characterized by Ranunculus sulphureus and by Saxifraga
oppositifolia. This community type shows a transition to
the Salix polaris-Silene acaulis type without any distinct
border; it also shows a transition to the most extreme
snowbed community characterized by scattered Sagina
n ivalis and Saxifraga tenuis, or by cryptogams only.
3.2 Spitsbergen
In the Spitsbergen data, the first TWINSP AN division
allocated the material into two main groups: ( 1 ) heath-like
vegetation characterized by Dryas octopetala, Luzula
arcuata ssp. confusa and/or Salix polaris, and (2) moss
dominated tundra and snowbed vegetation (Fig. 4). The
former main group was then divided into three groups
differentiated along topographic and edaphic gradients,
and to some extent along a regional (climatic) gradient.
The divisions result in the Luzula confusa group, the
Papaver dahlianum group and the Dryas octopetala group.
The latter main group was divided into three groups: wet
moss snowbeds, snowbed communities dominated by
Sanionia (the Sanionia snowbed communities) and moss
tundra communities dominated by robust mosses other
than Sanionia. Consequently, the Spitsbergen material is
summarized in six community groups containing alto
gether 1 6 community types or variants.
The main gradient structure of the Spitsbergen mate
rial resembles that of northern Fennoscandia (Fig. 1 4) .
The first DCA axis can be related to unequal snow distri
bution, as the snowbed sites with copious moss communi
ties are placed to the left and the deflation heaths with
poor plant cover lie to the right. On Spitsbergen, the
topographic gradient is related except for differential snow
depth and permafrost, as the depth of the active layer
varies along the topography (Eurola 1 968; R0nning 1 969;
SUiblein 1 97 1 ) . This influences the temperatures in
rhizosphere and moisture conditions: on slopes the melt
water seeps to grounds irrigating the soil surface during
the vegetation period. The second gradient is not easy to
interpret. The communities at the other end of the gradient
are characterized by Cassiope tetragona, Dryas octopetala
Acta Phytogeogr. Suec. 82
26 R. Virtanen & S. Eurola
and Bistorta vivipara. The mosses Hylocomium splendens
var. alaskanum and Tomentypnum nitens indicate nutri
ent-rich soil conditions relatively favourable conditions
of the inner fjord region. The other end of the second
gradient is occupied by communities characterized by
Cetrariella delisei and Racomitrium lanuginosum. The
community clusters with copious occurrence of R. lanu
ginosum originate from the southwestern coastal region,
and Papaver dahlianum communities prevail in climati
cally cold areas (Kjellstrom-Agardhdalen area). Conse
quently, the second gradient can be expected to reflect
both climatic and edaphic differentiation (gradient termed
'edaphic favourableness' ) . Due to regional differentiation
of the vegetation on Spitsbergen, the number of sample
plots in each of the three subareas (west-southwestern
coastal region, inner fjord region and Dryas region) are
indicated in the community descriptions. The regions are
abbreviated as C:I :D, respectively, followed by the number
of sample plots .
3.2.1 Luzula confusa group
Chionophobous-chionophilous heaths rich in bryophytes
and lichens; Appendix 7, Fig. 15a
This community group consists of three community clus
ters that are characterized by relatively high covers of
Cetrariella delisei, Luzula arcuata ssp. confusa and Salix
polaris. The moss layer is strongly fragmented with
Racomitrium canescens, R. lanuginosum, and Sanionia
uncinata as chief constituents with varying abundances in
the community types. This group of communities is diffi
cult to compare with any of the traditional alliances re
viewed by Elvebakk ( 1 994). In Eurola ( 1 968) this group
represents chiefly the 'Flechtenheide' vegetation of the
western coast (Cladina mitis region). The closest counter
parts can be found in the alliance Luzulion arcuatae
representing vegetation on moderate ridges with acidic
substrates. The clusters LcGC and LcRlC seem to repre
sent chionophobous communities, and LcSaC occupies
more sheltered sites (Fig. 1 4) .
Luzula confusa-Gymnomitrion corallioides community
(LcGC)
This community is characterized by Luzula arcuata ssp.
confusa and Salix polaris occurring with about equal
cover ( 1 1 - 1 2 %, on average). The bottom layer is chiefly
characterized by Cetrariella delisei and Sanionia unci
nata. Moreover, Gymnomitrion corallioides is relatively
abundant. The total number of species is high, but many
of them occur irregularly which may partly be due to a
mosaic vegetation structure created by polygon activity
(Fig. 1 8a). The less active polygon centres are colonized
by G. corallioides, and the interspaces have a more
Acta Phytogeogr. Suec. 82
4 ,3------�.-------.-------�--------.
3
+ C\1
! I 1.{) V e, 2 N } < 0
j 0 "i
2 3 4
DCA 1 (0.539)
Fig. 1 4a.
closed plant cover. In its floristic composition this com
munity seems to correspond partly to the Luzulo confusae
Salicetum polaris Hadac (Hadac 1 989). However, the
character species mentioned by Hadac ( 1 989) include
A nastrophyllum m inutum , Kiae ria glacialis and Tritomaria quinquedentata which are not characteristic
in our material. This type vegetation is wide-spread on
Spitsbergen C : I :D= 1 :4 :2 .
Luzula confusa-Racomitrium lanuginosum community
(LcRIC)
This community is characterized by patches of Raco
mitrium lanuginosum and a more uniformly developed
vegetation of Cetrariella delisei. In the field layer,
Saxifraga oppositifolia is the most prominent species,
while Cardamine bellidifolia is a characteristic subdomi
nant. In the ordination this community is placed among
chionophobous clusters with infertile soils (Fig. 1 4) . In its
species composition, this community seems to resemble
the Cetrariella delisei-Saxifraga oppositifolia tundra
(Nimis 1 985), included in snowbed communities of the
Luzulion nivalis by Elvebakk ( 1 994), but Racomitrium
lanuginosum occurs only scarcely. Elvebakk regarded it
ecologically as moderate snowbed. However, the occur
rence of Racomitrium lanuginosum suggests that this
community is chionophobous. On these grounds, this
community seems to correspond to vegetation in the Sphae
rophoro-Racomitrietum lanuginosi (Hofmann 1 968). It is
ecologically related to the R. lanuginosum dominated
communities which on Spitsbergen seem to be confined
-.] .5
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 27
..
.. Dry oct
.. Tom nit
Pol viv • • Hyl ala
.. ste riv
.. Aul tur • Alo alp
.. • Oxy dig Pol arp
.. Ste alp
.. Cer arc
.. Luz arc
.Pti cil • Die fus
•Rac can
•Cas tet
• Poa arc
• Hyp rev
L� con .. .. Pso hyp Bry sp
• Sax ces Och fri • .. Sax opp
Cet isl
GyDJ cor
Rac lan .. + Cet del
•cyanoba
+4.5
Fig. 1 4. Ordination diagram of axis 1 against axis 2 using Detrended Correspondence Analysis (DCA) for the TWINSPAN groups (a:
overleaO in the material of Spitsbergen. The centroids (points) are mean sample scores for the first two DCA axes. Circled areas indicate S.D. of the scores with respect to the axes. AtAbC - Aulacomnium turgidum-Alopecurus borealis community, AtHC - Aulacomnium turgidum-Hylocomium community, DocSaC - Dryas octopetala-Sanionia community, DocSpC - Dryas octopetala-Salix polaris community, DocTC - Dryas octopetala-Tomentypnum community, LcGC - Luzula confusa-Gymnomitrion corallioides community, LcRlC - Luzula confusa-Racomitrium lanuginosum community, LcSaC - Luzula confusa-Sanionia community, PdP - Papaver dahlianum polar desert, PdRpC - Papaver dahlianum-Racomitrium panschii community, RcOxC - Racomitrium canescens-Oxyria community, SaC - Sanionia snowbed community, SaPalpC - Sanionia-Poa alpigena community, SaShypC - Sanionia-Saxifraga hyperborea community, SoppHrC - Saxifraga oppositifolia-Hypnum revolutum community . DCA ordination of the species (only most common shown) (b) Alo alp - Alopecurus borealis, Aul tur - Aulacomnium turgidum, Bry sp - Bryum spp., Cas tet - Cassiope tetragona, Cer arc - Cerastium arcticum, Cet del - Cetrariella delisei, Cet isl - Cetraria islandica, Cyanoba - Cyanobacteria, Die fus - Dicranum fuscescens, Dry oct - Dryas octopetala, Gym cor - Gymnomitrion corallioides, Hyl ala - Hylocomium splendens var. alaskanum, Hyp rev - Hypnum revolutum, Luz arc - Luzula arctica, Luz con - Luzula arcuata ssp. confusa, Och fri - Ochrolechiafrigida, Oxy dig - Oxyria digyna, Poa alg - Poa alpigena, Poa alp - Poa alpina, Poa arc - Poa arctica, Pol alp - Polytrichastrum alpinum, Pol viv - Bistorta vivipara, Pso hyp - Psoroma hypnorum, Pti cil - Ptilidium ciliare, Rac can - Racomitrium canescens, Rac lan - Racomitrium lanuginosum, San unc - Sanionia uncinata, Sar sar - Sarmentypnum sarmentosum, Sax ces - Saxifraga cespitosa, Sax opp - Saxifraga oppositifolia, Ste alp -Stereocaulon alpinum, Ste riv - Stereocaulon rivulorum, Tom nit - Tomentypnum nitens.
Acta Phytogeogr. Suec. 82
28 R. Virtanen & S. Eurola
le GC lcRIC
b)
Le SaC
op I 0.363
4 I I PdP
c)
� I 0.305 I
8 [I] PdRpC SoppHrC
DocTC Docsac DoeS pC
Fig. 1 5a-c. TWINSPAN division.s �f a) the L
.uzula confusa group. LcGC - Luzula confusa-Gymnomitrion corallioides community,
LcRl.C - Luzula confusa-Racomltrzum
. lanugmosum community, LcSaC - Luzula confusa-Sanionia community . b) the Papaver
dahlzanum group. PdP - Papaver dahlzanum polar desert, PdRpC - Papaver dahlianum-Racomitrium panschii community. c) Dryas octopetala group. DocSaC - Dryas octop�tala-Sanionia community, DocSpC - Dryas octopetala-Salix polaris community, DocTC _
Dryas octo?etala-Tomentypnum commumty, SoppHrC - Saxifraga oppositifolia-Hypnum revolutum community . Numbers of sample plots and e1genvalues of the divisions are indicated.
to stable bouldery sites (Hartmann 1 980) and to more
oceanic parts of SW Spitsbergen (Triloff 1 944; Kuc 1 963;
Dubiel & Olech 1 990), occurring sporadically in the inner
fjord region (Hartmann 1 980) and northern parts of
Spitsbergen (Summerhayes & Elton 1 928; Brattbakk
1 983). In our material, this community was encountered
solely in the Homsund area (C: I :D=7:0:0) which further
strengthens its affinity to the oceanic Racomitrium
lanuginosum heaths (see also Virtanen et al. 1 997b) .
Luzula confusa-Sanionia community (LcSaC)
In the field layer of this community, Luzula arcuata ssp.
confusa is the most conspicuous species, and Salix polaris
reaches a mean cover of about 1 0%. In the cryptogam
layer Cetrariella delisei is only a minor constituent, while
Sanionia uncinata has a relatively high cover. Among
other mosses, Dicranum angustum and Hylocomium
splendens var. alaskanum are common. The community
seems to be more mesic in its species composition than the
two other communities in this group, and it is also placed
close to the moss tundra communities in the ordination
(Fig. 1 4). This community has a distribution with a centre
of occurrence in the coastal areas (western Isfjorden and
Homsund). C : I :D=3 :3 :0.
Acta Phytogeogr. Suec. 82
3.2.2 Papaver dahlianum group
Polar deserts and associated ridge communities; Appendix
8, Fig. 15b
This community group with two community clusters repre
sents the vegetation approaching vegetation of polar deserts
(Bliss et al . 1 984; Aleksandrova 1 988). At frrst sight, the
species composition and abundance relationships of the
two clusters seem to differ clearly from the rest of the
Spitsbergen material, thus it is surprising that they do not
fall into any extreme position in the ordination, but that they
lie between the Luzula confusa group and the Dryas
octopetala group. Soil movements combined with abrasive
winds are probably responsible for the sparse vegetation,
and these sites are also exposed to the coldest winter
conditions. At certain places in winter time, reindeer is
searching for food from sites with a thin snow cover, and
therefore grazing can also have a local impact on these
communities. The two clusters in this group are differenti
ated alike with regard to soil stability (intensity and fre
quency of cryoperturbation). These two clusters are best
understood as fixed points in a continuum from more or less
barren ridges to more closed communities on hill slopes.
Papaver dahlianum polar desert (PdP)
The total vegetation cover of this community cluster is
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 29
about 1 0% on average. The plant debris consists of Draba
spp. , Luzula arcuata ssp. confusa, Papaver dahlianum,
Poa arctica, and Potentilla hyparctica. Scatteredly grow
ing Tortula ruralis is a typical moss, while this commu
nity is devoid of any robust mosses. The occurrence of
such mosses is probably prevented by a high disturbance
rate. Among lichens, Cladonia pocillum is characteristic.
This community corresponds quite well to the Papaveretum
dahliani typicum (Hofmann 1 968) or to the Papaverion
dahliani (Hadac 1 946) . It is similar to the Papaver
dahlianum polar desert described from altitudes of 400-
600 m above sea level in the Adventdalen region (Virtanen
et al . 1 997b) . The nature of this community conforms
largely to that reported from polar deserts of Devon Is
land, Arctic Canada (Bliss et al . 1 994) . The sample plots
in this cluster were encountered in the Kjellstromdalen
Agardhdalen region. C : I :D=0:0:4.
Papaver dahlianum-Racomitrium panschii community
(PdRpC)
This community has a more closed plant cover than the
Papaver dahlianum polar desert type described above.
Here, Salix polaris, Saxifraga cespitosa, and S. opposi
tifolia are somewhat more abundant, in addition Cerastium
arcticum, Festuca hyperborea, and Minuartia rubella are
frequent. Hypnum revolutum and Racomitrium species
(Racomitrium canescens and R. panschii) occur rather
regularly . Lichen cover is also better developed than in
the Papaver dahlianum polar desert: e.g. Ochrolechia
spp. have a relatively high cover. This community repre
sents vegetation on exposed ridges showing a gradual
transition to polar desert vegetation and it corresponds to
the Papaveretum dahliani salicetosum polaris (Hofmann
1 968). This is included in the alliance Caricion nardinae
comprising vegetation on exposed ridges on alkaline and
circumneutral substrates (Nordhagen 1 936; Elvebakk
1 985, 1 994). This community is confined to the Dryas
region (Slettvika-Agardhdalen), C : I :D=0:0:4.
3.2.3 Dryas octopetala group
Xeric Dryas-bryophyte heaths; Appendix 9, Fig. 15c
The three community clusters, DocTC, DocSaC and
DocSpC, assigned to this group embrace chionophobous
chionophilous vegetation characterized by Dryas octopetala
occurring with a relatively high cover of 1 5-25%. The three
clusters overlap broadly in the ordination (Fig. 1 4), while
the fourth cluster, SoppHrC, is recorded in the relatively
extreme position along the first DCA axis indicating its
chionophobous nature. In this community, D. octopetala
has a low cover. Instead, many calciphilous plants thriving
on exposed ridges, e.g. Minuartia rubella, Saxifraga
jlagellaris and Silene furcata are characteristic.
The three clusters rich in Dryas octopetala can be
related to R�nning' s ( 1 965) classification scheme of the
Dryadion . He recognizes four communities: Nardino
Dryadetum, Rupestri-Dryadetum, Polari-Dryadetum, and
Tetragono-Dryadetum, differentiated chiefly in relation
to topographic position. The Nardino-Dryadetum and
Rupestri-Dryadetum communities appear to be missing in
our data. Community clusters resembling only the
chionophilous communities, the Polari-Dryadetum and
the Tetragono-Dryadetum, can be recognized. However,
the TWINSP AN analysis produced compositionally some
what different communities as compared to the descrip
tions of R�nning ( 1 965).
Dryas octopetala- Tomentypnum community (DocTC)
This community has a well-developed moss layer with
Aulacomnium turgidum, Hylocomium splendens var.
alaskanum and Tomentypnum nitens as the main constitu
ents (Fig. 1 6) . The most prominent vascular plants are
Dryas octopetala, Luzula arcuata ssp. confusa and Salix
polaris. The community roughly corresponds to the asso
ciation Cassiopo tetragonae-Dryadetum octopetalae
(Hadac 1 946; R�nning 1 965), partly to the Tomenthyp
netum involuti (Hadac 1 946) and to the Homalothecium
nitens-Dryas type of Elvebakk ( 1 994). This community is
relatively wide-spread on Spitsbergen C: I :D=0: 3 :4.
Dryas octopetala-Sanionia community (DocSaC)
This community resembles the DocTC in its species com
position, but Sanionia uncinata dominates the bottom
layer and Tomentypnum nitens is a subdominant. As sug
gested by the abundance of S. uncinata and its position in
the ordination (Fig. 1 4) , this community seems to repre
sent an intermediate type between moss tundra communi
ties and communities of the Dryas octopetala group.
There seems to be no counterpart described earlier. This
community is largely restricted to the inner fjord region
(the Adventfjorden-Sassendalen areas). C : I :D=0:9 : 1 .
Dryas octopetala-Salix polaris community (DocSpC)
Dry as octopetala and Salix polaris characterize the field
layer. Some of the sample plots have Cassiope tetragona
with a relatively high cover. Cerastium arctic urn occurs
with a cover of 0.5 %, and Poa arctica is frequent in
small numbers. The moss carpet is fragmented and none
of the species is very constant . Sanionia uncinata and
Tomentypnum nitens are the most abundant species. On
the basis of the ordination (Fig. 1 4) , this community is
slightly more chionophobous than the Dry as octopetala
Tomentypnum and D. octopetala-Sanionia communities
described above . This community resembles the 'Salix
polaris-Dryas octopetala -Soziat ion' of Hofmann
( 1 968 :29), and partly also the Tetragono-Dryadetum
(R�nning 1 965) . It is similar to the Dryas octopetala
Salix polaris community described in Virtanen et al.
Acta Phytogeogr. Suec. 82
30 R. Virtanen & S. Eurola
Fig. 1 6. Dryas octopetala-Tomentypnum tundra. Adventdalen, Mt. Louisfjellet. July 1 990. (Photo: Risto Virtanen.)
( 1 997b) . It may be regarded as a community occupying
slopes with thin snow cover, chiefly in the inner fjord
region of Spitsbergen. C : I :D = 0:4 :2 .
Saxifraga oppositifolia-Hypnum revolutum community
(SoppHrC)
This is the only community assigned to this group having
Dryas octopetala in low abundance and frequency. This
community resembles to a large degree the Papaver
dahlianum-Racomitrium panschii community (see above)
in its species composition. However, in comparison,
Racomitrium canescens and R. panschii are lacking, while
indicators of calcium carbonate-rich substrate are fre
quent (e .g. Distichium capillaceum, Ditrichum flexicaule
and Encalypta spp.) . The plant cover is more closed and
e.g. Saxifraga oppositifolia has a relatively high cover.
This community can be equaled with the Saxifraga
oppositifolia-Hypnum revolutum community in Virtanen
et al . ( 1 997b) occupying ridges on moderately cryoactive
sites. It is widespread on Spitsbergen (C: I :D=0:3 :2) in
transitions from closed vegetation to open screes . It
resembles the cushion plant-lichen and cushion plant-
Acta Phytogeogr. Suec. 82
moss communities reported from Truelove Lowland (Muc
& Bliss 1 977), the ridge communities from Bathurst Is
land (Sheard & Geale 1 983) and the Saxifraga opposi
tifolia-Luzula confusa based community type on Alexandra
Fiord uplands, Canadian High Arctic (Batten & Svoboda
1 994) .
3.2.4Alopecurus borealis-Aulacomnium turgidum group
Moss tundra vegetation; Appendix 1 1, Fig. 1 7a
This community group consists of four community clusters
representing moss-dominated tundra vegetation. The char
acteristic moss species include Aulacomnium turgidum,
Hylocomium splendens var. alaskanum, Sanionia uncinata
and Tomentypnum nitens. In the field layer such species as
Alopecurus borealis, Luzula arctica, L. arcuata ssp. confusa
and Salix polaris are characteristic. The abundance rela
tionships of mosses vary between community types. The
mosses reach a closed cover. This vegetation is showing a
transition to the Sanionia dominated snowbeds and to the
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 3 1
a ) b )
SaC SePal pC
SaShypC AtAbC AtHC RcOxC
Fig. 1 7a-b. TWINSPAN divisions of: a) the moss tundra communities . AtAbC - Aulacomnium turgidum-Alopecurus borealis community, AtHC - Aulacomnium turgidum-Hylocomium community, RcOxC - Racomitrium canescens-Oxyria community, SaShypC - Sanionia-Saxifraga hyperborea community ; b) the Sanionia snowbed communities. SaC - Sanionia snowbed community, SaPalpC Sanionia-Poa alpigena community.
mossy Dryas octopetala tundras (the Dryas octopetala
Sanionia community). This is visible in the ordination (Fig.
1 4), where one of the clusters, SaShypC, is close to the
Sanionia snowbed communities, and cluster RcOxC is
placed between the Dryas octopetala group and the moss
tundra communities. The boundary between Sanionia
snowbeds and moss tundra communities is diffuse. The
Luzula confusa-Sanionia community also lies close to those
in the ordination (Fig. 1 4) . The clusters SaShypC, AtAalC
and AtHC prevail in the Sveagruva-Kjellstromdalen area.
The communities dominated by Tomentypnum nitens are
central among the moss tundra communities described
earlier from Spitsbergen (Hadac 1 946; Hofrnann 1 968;
Philippi 1 973). In our material, none of the communities is
clearly dominated by T. nitens. In our plots, T. nitens
abounds in communities of the Dryas octopetala group.
This may be due to the fact that T. nitens does not thrive in
prolonged wet conditions (Hofrnann 1 968). These condi
tions favour hydrophytic mosses such as Scorpidium
revolvens. It seems better not to emphasize the presence or
absence of T. nitens in the moss tundra communities. In this
respect, the collective treatment of moss tundra communi
ties [following Eurola ( 1 968): the 'frische Moosheiden' ] is
justifiable.
Sanionia-Saxifraga hyperborea community (SaShypC)
In this community prevalent mosses include Dicranum
angustum, Polytrichastrum alpinum, especially Sanionia
uncinata, and hydrophilous Sarmentypnum sarmentosum.
In addition, characteristic bryophyte species include
Conostomum tetragonum and Gymnomitrion concinnatum.
The field layer is sparse: characteristic species are Phippsia
algida and Saxifraga hyperborea indicating snow bed con
ditions. In the ordination, this community is placed close
to the Sanionia snowbeds (Fig. 1 4) . This is probably an
intermediate community between the moss tundra com
munities and the Sanionia snow beds (the 'Drepanocladus
uncinatus-Schneeboden ' Hofmann 1 968; Philippi 1 973).
This community is encountered in the Slettvika-Kjellstrom
dalen area, C : I :D=0:0:6.
Aulacomnium turgidum-Alopecurus borealis commu
nity (AtAbC)
In this community, the most abundant moss is Aula
comnium turgidum. Dicranum majus, Sanionia uncinata
and Tomentypnum nitens are found less frequent. Some
hydrophilous mosses such as Sarmentypnum sarmentosum
and Scorpidium revolvens are relatively frequent. This
community is likely to show a transition to the wet snow bed
communities (see below and Fig. 1 8) and is characteristic
in the Dryas region (C: I :D=0:0:4).
A u lacomnium turgidum -Hylocomium community
(AtHC)
This community resembles the Aulacomnium turgidum
Alopecurus borealis community in its species composi-
Acta Phytogeogr. Suec. 82
32 R. Virtanen & S. Eurola
tion. These communities are also close to each other in the
ordination (Fig. 1 4) . In this community, hydrophilous
species are almost absent, instead Hylocomium splendens
var. alaskanum and Polytrichastrum alpinum occur with a
cover of 2-3%. This community, like the Aulacomnium
turgidum-Alopecurus borealis community, do not corre
spond well to the earlier descriptions of mossy tundras,
i .e. Tomentypnum nitens dominated tundras (Hadac 1 946;
Hofmann 1 968; Philippi 1 973) or dry or moist moss
heaths (Eurola 1 968). This community resembles the
Luzula confusa-Sanionia community (LcSaC, see above),
but has a relatively high cover of Tomentypnum nitens.
Moreover, the Luzula confusa-Sanionia community has
its main distribution in the coastal areas of western Isfjorden
and Homsund, whereas this community is restricted to the
Slettvika-Kjellstromdalen area (C:I :D=O: 1 :9) .
Racomitrium canescens-Oxyria community (RcOxC)
This community is also bryophyte-dominated, and now
Racomitrium canescens is the most abundant species. In
addition, Aulacomnium turgidum, Sanionia uncinata, and
Tomentypnum nitens are relatively abundant. This type of
vegetation includes sample plots with abundant Cassiope
tetragona (mean cover 20 % ). Otherwise, the field layer is
scarce: typical species are Luzula arcuata ssp. confusa,
Oxyria digyna and Stellaria longipes. Irregularly also
Draba alpina, Pedicularis lanata ssp. dasyantha and Si le ne
furcata are found. This community cannot be equaled
with the 'Racomitrium canescens-Gesellschaft ' described
by Philippi ( 1 973) from SE Spitsbergen. The community
described by Philippi is poorer in vascular plants and
represents a community on calcium-poor, dry substrate at
relatively high altitudes. This Racomitrium canescens
Oxyria community cluster partly contains early succes
sional communities near river shores on valley bottoms
(one of the plots is situated on a glacier foreland) and
partly relatively mesic chionophilous heaths on nutrient
rich sites. In the ordination, this community lies at an
intermediate position between the Dryas octopetala and
moss tundra communities (Fig. 1 4) . It is mainly found in
the inner fjord region (C:I :D=0:6: 1 ).
3.2.5 Sanionia snowbeds
Appendix 1 1, Fig. 1 7b
There are two community clusters recognized by TWIN
SPAN that are heavily dominated by Sanionia, whereas
other mosses rarely occur with covers of over 5 %. The
field layer is scarce: prostrate plants typical of snowbed
sites are creeping on the moss mat (Fig. 1 8d). Cerastium
regelii and Poa alpigena are the most characteristic spe
cies. Both of these clusters correspond to the 'Drepanocladus
uncinatus-Schneeboden ' (Hofmann 1 968; Philippi 1 973)
Acta Phytogeogr. Suec. 82
and to the 'Schneebodenstellen' (Eurola 1 968). Elvebakk
( 1 994) included these vegetation units in the alliance
Drepanoclado-Poion alpinae (Hadac 1 946). Relatively simi
lar communities dominated by Sanionia are found on Bear
Island (Virtanen et al. 1 997b ) .
In the ordination (Fig. 1 4), these two communities l ie
at an extreme position along the first DCA axis. They
show regional allopatry: the first (SaC) is present mainly
at the southwest-west coast area (Homsund), while the
other (SaPalpC) prevails chiefly in the Dryas region. The
two communities can thus be suggested to represent re
gional variants of a single community type.
Sanionia snowbed community (SaC)
The mean cover of Sanionia uncinata is about 60%, often
reaching 80- 1 00 %. Aulacomnium palustre, A. turgidum
and Calliergon stramineum are often present with a cover
of a few percentages. The field layer typically includes
Cerastium arctic urn, Salix polaris, Saxifraga oppositifolia
and S. rivularis. This community prevails chiefly in the
coastal areas of the Homsund region and in the mouth of
Isfjorden (C: I :D=6:2 :0).
Sanionia-Poa alpigena snowbed community (SaPalpC)
This community is closely similar to the Sanionia snow bed
community described above. The cover of Sanionia
uncinata is slightly lower (mean 45 % ). Tomentypnum
nitens is present with a mean cover of about 4 %. The field
layer is somewhat richer in its species composition: Bistorta
vivipara, Equisetum arvense and Poa alpigena and are
typical species. The dominance of Sanionia is lower, and
a grarninoid, Poa alpigena, is distinctly more abundant. One reason for the higher abundance of Poa alpigena in
the inland may be reindeer grazing. This community
prevails in the Slettvika-Kjellstromdalen region (C: I :D
=0:0: 8) where also reindeer occur, whereas in the SW
coastal area grazing is negligible (Punsvik et al. 1 980).
3.2.6 Wet moss snowbeds
Appendix 12, Fig. 4
Scorpidium revolvens-Tomentypnum snowbed community
This community cluster distinguished by TWINSP AN is
dominated by Scorpidium revolvens and Tomentypnum
nitens. Campylium stellatum, Sanionia uncinata and
Sarmentypnum sarmentosum are also relatively abun
dant. The field layer is characterized by Bistorta vivipara,
Equisetum arvense and E. variegatum, and with some
Saxifraga hirculus and S. oppositifolia . These wet
snowbeds can be expected to show a transition to the
arctic mire vegetation (Eurola 1 97 1 ) . Such gradients
have been described in northern Spitsbergen (Reindeer
Peninsula) by Dahle ( 1 983) : Sanionia communities occur
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 33
a
b
Fig. 1 8 . Tundra vegetation NE of van Mijenfjorden, near Darnesmorena. (a) Wind-exposed Luzula confusa-Gymnomitrion tundra. Polygon centres mostly plantless. (b) Aulacomnium turgidum-Hylocomium-rich tundra, with raised polygon centres. (c; overleaf)
Alopecurus borealis-Aulacomnium-rich tundra, with reticulate frost patterns. (d; overleaf) W of Darnesmorena, topographic ridgedepression transect. Above Barren communities approaching polar desert, depression Sanionia snowbed communities and wet moss communities . July 1 969. (Photos: Seppo Eurola.)
Acta Phytogeogr. Suec. 82
34 R. Virtanen & S. Eurola
between Dryas heaths and wet snowbeds. The Sanionia
snowbeds are more hydrophytic in nature, approaching
the wet snowbeds with the mosses Pseudocalliergon
turgescens (= Scorpidium turgescens) and Scorpidium
revolvens (= Drepanocladus revolvens) as prominent
species. The latter species is frequent and abundant also
in the wet moss snow beds in the Kjellstrom-Agardhdalen
Acta Phytogeogr. Suec. 82
Fig. 1 8c
d
area. The wet moss snow beds are obviously wide-spread
on Spitsbergen in the inner fjord and Dryas regions
(C : I : D=0:2 :3) . Comparable moss communities are re
ported from Bathurst Island, Arctic Canada (Miller & Alpert 1 984) and from Barrow, Alaska (Rastorfer 1 978).
4 Topographic patterns: series of communities
in ridge-depression transects
Both in northwestern Fennoscandia and on Spitsbergen,
the topographic variation and consequent uneven distri
bution of snow cover and moisture account for the pri
mary pattern of vegetational variation at a given altitude
as is generally observed in the arctic and alpine environ
ments (e.g. Vestergren 1 902; Nordhagen 1 928; Dahl 1 957;
R�nning 1 969). The topographic variation gives rise to
series of communities (= community complex) from wind
exposed ridges to depressions with more or less late-lying
snow fields. In many earlier works, the community series
have been illustrated using transect data (e.g. Dah1 1 957;
Gjrerevoll 1 956; R�nning 1 969; Brossard et al . 1 984;
Oksanen & Virtanen 1 995), which makes it possible to
characterize the small-scale variation in vegetation. In
this study, focusing on larger scale patterns, the essential
features can be idealized based on ordination and classifi
cation schemes. Moreover, field notes and comparisons
with earlier l iterature have been used to increase the
understanding of the data.
4.1 Northwestern Fennoscandia
In the middle oroarctic zone of northwestern Fennoscandia,
two major series of communities are recognized along a
ridge-depression transition:
( 1 )1he series on siliceous substrate. In the DCA ordination,
this series makes a cross-section from the communities of the
Alectoria group to the latest snowbed communities of the
Ranunculus glacialis group (Fig. 5, Fig. 1 9a). On wind
exposed ridges, heaths of the Empetrum-Cassiope tetragon,a
Alectoria type or the Empetrum-Cassiope tetragona type are
found. The former type represents communities with their
main distribution on continental mountains (the Empetrum
Phyllodoce-Alectoria type and the Vaccinium-Alectoria types
in Oksanen & Virtanen 1 995), while the latter type has
affinity with the suboceanic-oceanic heaths dominated by
Empetrum nigrum ssp. hermaphroditum (Haapasaari 1 988).
The occurrence of both types in the Kilpisjarvi district is not
surprising since this district is transitional between continen
tal and oceanic climate (Hamet-Ahti 1 963). Both types are
encountered on relatively stable soil substrates where dwarf
shrubs are able to reach a relatively high cover. The top
plateaux with patterned ground are characterized by the
Gymnomitrion type. In polygonal terrain, the frost boils are
often largely devoid of higher plants and colonized by
Gymnomitrion spp. and the hollows between elevations may
harbour chionophilous or even hydrophilous plants.
When the snow cover increases, cryoactivity decreases,
as well as the impact of abrasive winds; snow cover gives
protection against drought in early spring. At these weakly
chionophobous sites, the conditions are relatively favour
able, and the vegetation occupying these sites represent
the Empetrum-Flavocetraria nivalis type, wide-spread in
the subcontinental lower oroarctic zone ( = Empetrum
Cetraria nivalis type in Haapasaari 1 988; Oksanen & Virtanen 1 995: fig. 26) . In our study area, the communi
ties characterized by Empetrum nigrum ssp. herma
phroditum reach altitudes of about 950 m, extending only
sporadically to higher elevations. In northerly exposed
slopes, Empetrum heaths are confined to markedly lower
altitudes. Thus, E. nigrum ssp. hermaphroditum might be
regarded as a thermophilic species in the middle oroarctic
zone, where the presence of Cassiope tetragona suggests
a further narrowing of the habitat range.
The Empetrum-Flavocetraria nivalis type shows a
transition to the ]uncus trifidus-Cassiope tetragona type,
which represents the core of the weakly chionophilous
vegetation of the middle oroarctic zone (e.g. Nordhagen 1 943 ; Oksanen & Virtanen 1 995). The type is broad
including a wide array of ecologically differentiated vari
ant communities. In the Kilpisjarvi district, a community
with eo-occurring Cassiope tetragona and ]uncus trifidus
in the field layer, described as the typical variant of JtCtT,
is prevalent. The mixed community probably indicates
site conditions in which various factors maintain a dy
namic equilibrium between these two species, which in
principle, occupy partially overlapping ecological niches.
Both of the species are chionophilous, but C. tetragona is
weakly calciphilous (Nordhagen 1 955) and J. trifidus
strongly acidophilous (Nordhagen 1 943; Dahl 1 957). How
ever, in the ordination (Fig. 5b), a reverse pattern is
observed: C. tetragona is noted in the acidophilous area of
the ordination space, while J. trifidus is closer to the
calciphilous communities. Some other factors may thus
underlie this pattern. First, there are differences in eco
logical amplitude with respect to snow cover: J. trifidus
tolerates relatively late-lying snow conditions well (Nord
hagen 1 943; Bocher 1 963 ; Oksanen & Virtanen 1 995),
whereas C. tetragona has the highest abundance on stable
weakly snow-protected and/or sheltered slopes at lower
parts of the middle oroarctic zone. Only at such sites,
C. tetragona can monopolize the space. In extreme cases,
the only coexisting species can be mosses such as Hylo
comium splendens var. alaskanum. C. tetragona may be
sensitive to the reindeer trampling, because its stems lie
Acta Phytogeogr. Suec. 82
36 R. Virtanen & S. Eurola
on the surface as do the stems of Empetrum nigrum ssp.
hermaphroditum (Callaghan & Emanuelsson 1 985). In
stead, J. trifidus tolerates trampling well due to its tussock
growth form with rhizomes forming a tightly packed
network of short branches. It may be that the ordination
also reflects community differentiation imposed by graz
ing pressure.
At Kilpisjarvi, the other major element of the tradi
tional Juncion trifidi (Nordhagen 1 943), the oligotrophic
Festuca ovina heaths are missing. In our material, heaths
rich in F. ovina are found at Mt. Saana, where they occupy
relatively nutrient-rich sites (the Festuca ovina-Potentilla
crantzii group). Thus, the cooccurrence of F. ovina and J.
trifidus heaths at Kilpisjarvi cannot be used as a straight
forward indication of climatic differentiation in the same
way as in the southern part of Norway where ]uncus
trifidus heaths are considered as a more oceanic vegeta
tion than F. ovina heaths (Nordhagen 1 943) .
Into the direction of delayed snow-melt, the ]uncus
trifidus-Cassiope tetragona heath vegetation gradually
changes into heath-like snow beds of the ]uncus trifidus
Cassiope hypnoides type (Oksanen & Virtanen 1 995).
This type seems to become wide-spread at higher alti
tudes and it is not a typical member of the community
series. It is likely that intensified soil cryoactivity and
solifluction fragments ]uncus trifidus and Cassiope
tetragona clones leaving space for better disturbance
adapted species such as Luzula arcuata ssp. confusa.
This type prevails in the gradient from the middle oroarctic
zone to the upper oroarctic vegetation and it often coexists
with the Cassiope tetragona-Ranunculus glacialis type found on upper oroarctic ridges (Oksanen & Virtanen
1 995).
The persistence of snow cover up to late June or early
July, gives rise to true snowbed vegetation, which is
represented by two types: the Salix herbacea-Cassiope
hypnoides type and the Salix herbacea-Kiaeria type with
its Carex bigelowii variant. The Salix herbacea-Kiaeria
type prevails on sites with later-lying snow (Oksanen & Virtanen 1 995), while the Salix herbacea-Cassiope hyp
noides type emerges earlier from the snow and changes
directly to a heath vegetation of the ]uncus trifidus
Cassiope tetragona type and to the snow bed vegetation of
lower altitudes (the ]uncus trifidus-Deschampsiaflexuosa
type and the ]uncus trifidus-Cladina mitis type, Oksanen
& Virtanen 1 995). The snowbed vegetation characterized
by Salix herbacea is found on sites that are drained during
the growing season. On sites that are irrigated by melt
water or are otherwise moist, as in some depressions with
more or less level ground, the Carex bigelowii type (CbT)
prevails. Moreover, these Carex bigelowii snowbeds
emerge earlier from snow as they usually are situated
away from the latest snow-fields (Nordhagen 1 928). On
intermediate sites, one can encounter the Carex bigelowii
variant of the Salix herbacea-Kiaeria type.
Acta Phytogeogr. Suec. 82
In sites adjacent to the latest snow fields, still existing
in the turn of July-August, the abundance of cryptogams
increases and vascular plants become scattered. In our
material, the vegetation of the latest snow beds represents
the Ant he lia juratzkana-P olytric hastrum sexang ulare type
corresponding to the snowbed communities without a
field layer of Gjrerevoll ( 1 956).
Overall, the series on siliceous substrates corresponds
to the pattern introduced from subcontinental mountains
of northern Fennoscandia (Oksanen & Virtanen 1 995).
This study suggests that on level plateaux and in wide
depressions there are communities that are not members
in the mesoscale topographic ridge-depression series. The series on siliceous substrate is distinctly different from
any of the community series of Spitsbergen.
(2) The series on calcareous substrate. This parallel series
of communities along a ridge-depression transition can be
abstracted. The series lies in the middle of the second
gradient of the DCA ordination (Fig. 5, 1 9b). The ridges
are occupied by heaths of the Dryas octopetala-Carex
rupestris type which shows a transition to chionophilous
communities of the Cassiope tetragona-Dryas octopetala
type. The ridge communities and weakly chionophilous
heaths are relatively similar to vegetation encountered in
the corresponding sites of Spitsbergen. These heaths of
northwestern Fennoscandia thus represent a link to
circumpolar arctic vegetation (Gjrerevoll 1 954; Bocher
1 963 ; R�nning 1 965 ; Eurola 1 974). The Salix polaris
Silene acaulis type represents early snowbeds, and the
latest snowbeds are occupied by the vegetation of the
Saxifraga oppositifolia-Ranunculus sulphureus type. Over
all, this series is similar to the one described by Gjrerevoll
( 1 956:33) from Swedish Tome Lappmark. In the latest
snowbeds on calcareous substrates, communities domi
nated by Distichium capillaceum have been found by
Gjrerevoll ( 1 956), but such communities were not en
countered by us. The peculiar Koenigia-Phippsia com
munity is found close to melting snow-fields maintaining
continuous irrigation (Pililsson 1 994: fig . 1 :9) . The
chionophilous-snowbed communities of northern Fenno
scandia have little in common with corresponding com
munity types on Spitsbergen. Fennoscandian snowbeds
show at least physiognomic resemblance to the corre
sponding communities on Alaskan mountains (Gjrerevoll
1 980), although in Alaska the mosses appear to be rela
tively abundant as compared to hepatics (AI pert & Oechel
1 982).
A third series, encountered only on the slopes of Mt.
Saana, is clearly different from the two major ones : the
community series of the Festuca ovina-Potentilla crantzii
heaths appears in the lower part of the ordination space
(Fig. 5, 1 9c). The series is characteristic of sites with
moderately calcareous substrates on slopes with rela
tively favourable climate. On the ridges, we encounter a F estuca ovina and Dryas octopetala dominated community
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 37
that shows affinity with the Dryas octopetala-Carex
rupestris type. At the chionophilous sites, communities
belonging to the Festuca ovina-Potentilla crantzii type
are prevalent. These communities show a transition to the
early-melting snowbeds characterized as the Festuca
ovina-Saussurea alpina-Sanionia snowbed communities .
The relatively late snowbed sites harbour a vegetation of
the Trisetum spicatum-Sanionia type, also a member in
the suboceanic series of communities of Oksanen & Virtanen ( 1 995).
4.2 Spitsbergen
As in northwestern Fennoscandia, the community series
of Spitsbergen, can be abstracted along the ridge-depres
sion transitions . The gradient analysis (Fig. 1 4) suggests
that the communities of Spitsbergen do not fall into dis
tinct edaphic series, as is the case in northern Fennoscandia.
Instead, the series can be idealized for each climatically different subareas. Consequently, we distinguish three
series (Fig. 20) : ( 1 ) the inner fjord region; (2) the west
southwestern coast region; and (3) the Dryas region.
In the inner fjord region, two types of ridge heaths
prevail (Fig. 20a): ridges with often active patterned ground
are occupied by relatively open communities, character
ized by Saxifraga oppositifolia (the Saxifraga oppositifolia
Hypnum revolutum community). This vegetation extends
to mountain slopes up to the limits of more or less continu
ous plant cover (Virtanen et al . 1 997b). Corresponding
communities are reported also from the Ny Alesund area
(Brossard et al. 1 984) and from the Dryas region (this
study). The Saxifraga oppositifolia-Hypnum revolutum
community is relatively broad and contains sample plots
approaching the Potentilla pulchella community, so far
only anecdotally described (Elvebakk 1 994). On slightly
less extreme ridges with largely stable substrates, the
Dryas octopetala-Carex rupestris community prevails
(Virtanen et al. 1 997b). This community is also reported
from the Ny Alesund area (R�nning 1 965 ; Brossard et al .
1 984 ). On ridges in areas between the inner fjord region
and the western coast, the Luzula confusa-Gymnomitrion
community is encountered.
The most outspoken chionophobous communities de
scribed above show a transition to Dryas octopetala-Salix
polaris communities. The Cassiope tetragona heaths did
not form any distinct community clusters in our numerical
classification. These communities are, however, rather
regularly encountered in the inner fjord region (see also
Eurola 1 968; Virtanen et al . 1 997b) . Into the direction of
increasing snow cover, C. tetragona abruptly vanishes,
probably due to a too short snow-free period and/or too
shallow active layers (cf. Nams & Freedman 1 987). In the
depression sites, the abundance of vascular plants further
diminishes and the communities become heavily domi-
a)
Gymnomitrion type (on plateaux) Empetrum-Cassiope tetragona-Aiectoria t . (on smaller ridges)
Ridge
b)
Empetrum-Fiavocetraria nivalis t.
Juncus trifidus-Cassiope tetragona t
Salix herbacea-Kiaeria t.
Anthelia juratzkana-Poly-.
trum sexangulare t Depression
Dryas octopetala-carex rupestris type
c)
Festuca ovina-Dryas octopetala community
Fig. 1 9a-c. Generalized community series along ridge-depression topographic sequences in the middle oroarctic zone of northwestern Fennoscandia: a) siliceous substrate, b) calcareous substrate, c) eutrophic (slightly calcareous) substrate.
nated by mosses. The Dryas octopetala-Tomentypnum
community occupies sites of moderately late-lying snow
while the Dryas octopetala-Sanionia community occurs
on late-lying snow beds. The latest snowbeds of the inner
fjord region are poorly represented in our material. Some
of them are assigned to the Racomitrium canescens-Oxyria
community and some to the Sanionia-Poa alpigena
snow bed community, chiefly encountered in the Dryas
region. These moss-dominated communities occur more
sporadically in the inner fjord region (Eurola 1 968) where
frost churning often breaks the moss carpet and also
reindeer trampling may have similar effects . In wet de
pressions, snowbed communities with hydrophilous
mosses, e.g. Scorpidium revolvens, are found. These com
munities are often characterized by Dupontia .fisheri and
Eriophorum scheuchzeri.
On the west-southwestern coast of Spitsbergen (Fig .
20b ), a somewhat different series of communities is
found. A community with relatively abundant Raco-
Acta Phytogeogr. Suec. 82
38 R. Virtanen & S. Eurola
mitrium lanuginosum, the Luzula confusa-Racomitrium
lanuginosum community, is characteristic for stable
ridges, whereas on unstable substrates the moss carpet i s
fragmented (the Luzula confusa-Gymnomitrion commu
nity, Eurola 1 968). These vegetation types grade to
lichen and moss-rich Luzula confusa-Sanionia commu
nities, while depression sites harbour the Sanionia
snowbed communities (Kuc 1 963 ; Eurola 1 968) . This
series is characteristic of southwestern Spitsbergen, but
Luzula confusa-Gymnomitrion community is widespread
and extends to Dryas region, where this type of vegeta
tion shows a transition to polar deserts. In the Ny Alesund
area, the northern part of the west coast, the typical
community series resembles more that of the inner fjord
region and the Dryas region. As shown by R�nning
( 1 969) and Brossard et al. ( 1 984), ridge communities are
characterized by Carex rupestris and Dryas octopetala ,
which show a transition to a community with tufts of
Deschampsia alpina and a cryptogam layer with dark
bryophytes .
a)
Sadfraga oppositifolia-Hyprum revolutum commt.rity
(Dryas octopetaa-CEI'ex rupestris c.) Ridge
Dryas octopetaa-Salix pdaris c.
b) Depression
Luzula coofusa-Gymnomitrion coraiUoides community
Luzula coofusa-Racomitrium laruginosum c.
Luzula coofusa-SGiliooia c.
c)
Papaver d81�arum pdEI' desert
------ Papaver d81Narum-Racomitrium panschii community
(Dryas octopetala-Tomertypm1n c.)
Auacan nium turgidllll-Hylocomium c.
SGiliona-SaiCifraga t?,tperborea c.
Fig. 20a-c. Generalized community series along ridge-depression topographic sequences on Spitsbergen: a) the inner fjord region, b) the west-southwestern coast region, c) the Dryas region.
Acta Phytogeogr. Suec. 82
In the Dryas region (Fig. 20c) (Summerhayes & Elton
1 928; Eurola 1 968) which largely corresponds to the north
ern arctic tundra zone (Elvebakk 1 985), the exposed ridges
are characterized by the Papaver dahlianum polar deserts
and associated less extreme Papaver dahlianum-Raco
mitrium panschii communities. With increasing snow depth
these show a transition to communities of the Dryas
octopetala group, of which the Dryas octopetala
Tomentypnum community from inner fjord region is also
found. These are accompanied by moss tundra communi
ties (theAulacomnium turgidum-Alopecurus borealis com
munity, the Aulacomnium turgidum-Hylocomium commu
nity and the Sanionia-Saxifraga hyperborea community)
which correspond to the Luzulion arcticae vegetation
(Elvebakk 1 985). The depressions are occupied by the
Sanionia-Poa alpigena snowbed communities. Similar com
munities as in our material from the Dryas region are
reported from SE Spitsbergen, e.g. on Barents Island
(Hofmann 1 968) and in northernmost Spitsbergen (Rein
deer Peninsula, Dahle 1 983).
5 V egetational differentiation in relation to edaphic factors
In northwestern Fennoscandia, a division into types on
calcareous soils and oligotrophic types on calcium-poor
soils seems to be clear along the topographic ridge-de
pression gradients. This conforms to earlier studies from
other mountains of Fennoscandia (e.g. Nordhagen 1 928;
1 943; Kalliola 1 939; Gjrerevol1 1 956), or the Alps (Gigon
1 97 1 ) and Alaska (Cooper 1 986) . Although the podzol
profile is weakly-developed in the middle oroarctic zone,
leaching is probably a process contributing to the distinct
division into siliceous and calcareous soils. Precipitation
is high; there is no permafrost layer counteracting water
percolation, and the plant cover includes edificator plants,
e .g . Betula nana, Cassiope tetragona, and Empetrum
nigrum ssp. hermaphroditum. On siliceous soil parent
material, these acidophilous plants may decrease base
exchange capacity and base saturation in the soil, and
exudate compounds promoting soil acidification (e.g.
Lundegardh 1 957; Miles 1 987). On the contrary, on cal
careous bedrock, supply of cations is continuous enough
to maintain base status and pH values close to the soil
surface. Although the edaphic gradient is mostly distinct,
there are circumstances where this distinctness becomes
weak or disappears.
( 1 ) The species composition of the Carex bigelowii-Salix
polaris type includes about equal ly both acidophilous
( Cassiope hypnoides, Luzula arcuata ssp. confusa, Salix
herbacea) and calciphilous plants (e.g. Salix polaris and
Silene acaulis) and it seems to represent intermediate
vegetation between acidophilous and calciphilous ones. It
may be that the chemical properties of the underlying soil
are intermediate, as a consequence of weak leaching.
Furthermore, melt water may provide an extra cation
addition and wash the humic acids off. One more factor
that may contribute to coexistence of edaphically differ
entiated species is reindeer grazing. Grazing can decimate
the cover of ericaceous dwarf shrubs and robust lichens
( Cladina arbuscula ssp. mitis and/or C. stellaris) (see also
Manseau et al . 1 996). Consequently, space is created for
calciphilous species that are normally excluded through
competition.
(2) On polygonal sites where soils of polygon centres
have higher concentrations of extractable plant nutrients
and higher pH values than in the surrounding stable ground
on otherwise siliceous substrates (Rintanen 1 970; Jonasson
& Skold 1 983; Jonasson 1 986). These polygonal soils
may thus provide substrate for plants growing normally
on calcareous soils. One example is the occurrence of
Dryas octopetala in heaths of the Gymnomitrion type.
Northern Fennoscandia differs from Spitsbergen in
that on Spitsbergen the whole range of communities in
cludes species that can be regarded as calciphilous in
northern Fennoscandia. Communities with solely
acidophilous species seem to be missing in our material
from Spitsbergen, and the floristic element confined to
acidic soils is rare on Spitsbergen (cf. Table 2). This
probably reflects presence of base-rich bedrock on
Spitsbergen, but some other factors, such as omnipres
ence of permafrost, a high frequency of cryoperturbation
as well as low precipitation, counteract leaching and
prevents formation of as acidic soils as on mountains of
northern Fennoscandia.
On Spitsbergen, plants possess edaphic preferences
(Elvebakk 1 982), but the relationship between climatic
conditions, soil and vegetation have not been much dis
cussed. The present analysis provides some evidence that
the relationship may vary depending on the geographic
scale. In the inner fjord region of Spitsbergen, the valleys
receive little precipitation (Hisdal 1 976). The precipitation
per evaporation ratio is low, and even arid conditions can
prevail. Under such conditions, soils especially on well
drained ridges are amphipercolative, and the upper soil tend
to become enriched by calcium carbonate and the soil will
become basic. This is supported by the soil analyses of
Federoff ( 1 966). On such ridges, the edaphic tolerances of
many common species may be exceeded, and instead a
rather specialized group of exacting calcitrophic species
can be found regularly (e.g. Potentilla pulchella). Similar
edaphic processes prevail also on the continental Rocky
Mountains (Bamberg & Major 1 968). More closed vegeta
tion prevail in the surroundings of the exposed ridges. The
soils are also more acidic (Federoff 1 966) especially
Cassiope tetragona and Hylocomium (Rszsnning 1 965 ;
Federoff 1 966). It is possible that acidification takes place.
Consequently, edaphic differentiation of vegetation exist in
the inner fjord region, but the differences may also reflect
an impact of vegetation on the soil and not only differences
in soil parent material.
In a regional scale, climatic factors can play a signifi
cant role. The vegetational series from the coastal region
(Fig. 20b) indicates the relatively acidophilous nature of
vegetation (the Luzula confusa-Racomitrum lanuginosum
community, for example), although soil substrates in
clude calcareous ones. Nevertheless, indicators of cal
cium carbonate tend to be infrequent. One reason may be,
that the precipitation is relatively high, promoting leach
ing of polyvalent cations from upper soil layer. Moreover,
Acta Phytogeogr. Suec. 82
40 R. Virtanen & S. Eurola
the moist climate favours acidophilous moss, Racomitrium
lanuginosum and such lichens as Cetrariella delisei and
Cladina arbuscula ssp. mitis. It can be supposed that R.
lanuginosum functions to some extent l ike Sphagnum
causing considerable changes in their local environment
by absorbing available cations. Its ability to form exten
sive moss carpets is also a property that can be regarded as
a competitive mechanism that may result in the exclusion
of other mosses and vascular plants. In short, the observed
(at least weakly) acidophilous nature of vegetation on the
southwest-west coastal area of Spitsbergen results from
climatic reasons directly promoting soil leaching and
indirectly favouring acidophilous plants.
The third pattern in vegetation-soil relationships re
flects the cooling down of climate from favourable areas
a)
towards polar deserts. Along this gradient, cryoperturbation
can be expected to become more intense and the active
soil layer to become thinner (cf. SHiblein 1 97 1 ) . Moreo
ver, precipitation decreases. These factors counteract leach
ing. Plant cover is sparse and the nutrient demands can be
supposed to be more or less saturated. Cation exchange of
plants is slow and it hardly leads to excess of H+ ions and
soils do not become acidic . Therefore, it can be expected
that in the climatically colder areas soil parent material
plays a less significant role for plants, and the plants most
frequent on the cold areas can be regarded as circumneutral
(Sumrnerhayes & Elton 1 928 ; Eurola 1 968, 1 974). This is
also reflected in our data: the species composition in the
Dryas region gives impression of a higher proportion of
calciphilous or neutrophilous mosses and vascular plants.
c:::J Vascular plants
1 00
'# 80 (].) C) CO
� 0 u (].) > � 05 er:
60
40
20
1 00
0 � 80 Q) O'l CO
� 0 u Q) -� (i5 05 er:
60
40
20
GymnT ECtAT JtCtT ShKiT APsT
b)
OocCrT OocCtT SpSacT SoppRsT
c)
FovOocC FovPcrT FovSalpSaC TsSaT
Acta Phytogeogr. Suec. 82
� Robust mosses � Other bryophytes fl'll!l Lichens + black crust
Fig. 2 1 a-c. Relative coverages (%) of vascular plants, robust mosses, other bryophytes and lichens in generalized community series along ridge-depression topographic sequences in the middle oroarctic zone of northwestern Fennoscandia: (a) silicaceous substrate; (b) calcareous substrate; (c) eutrophic (slightly calcareous) substrate. See text for further explanation.
6 Abundance patterns of bryophytes in
topographic and regional gradients
In terms of general vegetation composition the chiono
phobous and weakly chionophilous heath vegetation of
the middle oroarctic zone in northern Fennoscandia is
composed of communities in which the ericaceous and
graminaceous plants are the two major groups of vascu
lar plants. The cryptogam layer is characterized by a
large number of bryophytes and lichens (App. 2 and 3) .
These heaths show a transition to the upper oroarctic
vegetation consisting of relatively open Luzula arcuata
ssp. confusa and Ranunculus glacialis communities (Du
Rietz 1 925 ; Oksanen & Ranta 1 992; Oksanen & Virtanen
1 995) . Communities of ridge and snowbed sites of the
middle oroarctic zone are rich in prostrate plants, small
mosses and hepatics (App. 4). The most extreme
snowbeds are characterized mainly by small mosses and
hepatics (e .g. the Anthelia juratzkana-Polytrichastrum
sexangulare type, App. 5) .
In the inner fjord region of Spitsbergen, sparsely snow
covered ridges are replaced by communities rich in grasses
and prostrate plants (the Dryas octopetala-Carex rupestris
and open Saxifraga oppositifolia-Hypnum revolutum com
munities). Dwat-f shrub communities, i .e . heaths rich iil
Cassiope tetragona are confined to narrow zones on shel
tered slopes. Lower parts of hill slopes and depressions
are occupied by the moss-rich tundra communities (e.g.
the Dryas octopetala-Tomentypnum community, App. 9).
In the west-southwestern coastal area, dwarf shrub heaths
are missing and moss and lichen-rich communities pre
vail on wind-swept and depression sites. In the Dryas
region, a large proportion of the landscape is sparsely
vegetated and ridge heaths approach polar desert vegeta
tion with scattered Papaver dahlianum (App. 8) On shel
tered sites the moss-rich communities of the Dryas
octopetala group cover a larger proportion of the terrain
and moss tundra communities become prevalent (App.
1 0) . Both in the coastal and Dryas region, and locally in
the inner fjord region, the snowbed sites are occupied by
mosses forming thick carpets, such as Sanionia (A pp. 1 1 ).
The distribution pattern of communities outlined above
suggests that the plant composition of chionophilous and
snowbed communities differ distinctly between northern
Fennoscandia and Spitsbergen. One of the main differ
ences concerns the abundance of bryophytes. This is
shown in the Figs. 14 and 1 5 where relative abundances
of:
( 1 ) robust mosses, building thick carpets by means of
vegetative growth, are loosely attached to the ground and
are susceptible to trampling or other physical disturbance
(Aulacomnium, Brachythecium turgidum, Cirriphyllum,
Hylocomium, Orthothecium chryseum, Pleurozium, Raco
mitrium, Rhytidium, Sanionia, Sphagnum and Tomen
typnum spp.) .
(2) al l other bryophytes that are different in these
characters (hepatics, e.g. Anastrophyllum, Gymnomitrion,
Lophozia spp. and small mosses, e.g. Dicranum, Disti
chium, Tortula spp.) . It seems that in northern Fenno
scandia, most of the communities are dominated by
vascular plants and by other bryophytes (the second
group above) and lichens (Fig. 2 1 ) . In contrast, on
Spitsbergen (Fig. 22), robust mosses consistently domi
nate chionophilous and snow bed sites. Furthermore, moss
dominance increases towards depression sites and from
the inner fjord region towards the coastal and Dryas
region (Fig. 22).
It has been suggested that reduced competition by
vascular plants is one of the causes for the moss abun
dance in the middle-northern arctic areas (Tallis 1 958 ;
Vitt & Pakarinen 1 977). Indeed, i t is possible that abiotic
conditions are favourable to mosses rather than to vascu
lar plants in these areas. Soils are more unstable due to
solifluction and cryoturbulence, thus roots of vascular
plants are broken, and low temperatures due to permafrost
reduce root development (Bell & Bliss 1 978). Permafrost
impedes drainage and maintains a high concentration of
mineral elements in the soil, which in turn may favour
mosses. However, a copious moss vegetation is found in
the uplands of the Faeroe Islands and Iceland where there
is no permafrost (Bocher 1 937; Bjamason 1 99 1 ) . 1t can be
readily noticed that these areas are more oceanic and
receive high precipitation which contributes to abundant
moss vegetation (Du Rietz 1 925). However, a copious
moss vegetation is not only confined to areas with high
precipitation, as such vegetation is also found in continen
tal parts of the circumpolar high arctic with remarkably
low precipitation (Vitt & Pakarinen 1 977; Sumina 1 986).
As the mountains of northern Fennoscandia receive an
amount of precipitation which is comparable to oceanic
areas (Waiter & Lieth 1 975) and the mountains are often
covered by clouds which provide further irrigation in the
form of fog, it is surprising that no similar copious moss
communities are commonly found. Actually, such veg
etation is not totally missing from Fennoscandia. In the
upper oroarctic habitats, patches of thick moss carpets
occur as isolated oases in sterile boulder fields (e.g. on the
upper slope of Skuvgilrassa in interior Finnmark, Oksanen
& Virtanen 1 99 5 ) and at the highest altitudes on
Acta Phytogeogr. Suec. 82
42 R. Virtanen & S. Eurola
Fennoscandian mountains (Vestergren 1 902; Du Rietz
1 925). Consequently, mere physical constraints do not
seem to provide a sufficient explanation for the absence of
moss banks below the altitudinal limit of continuous
vegetation in northwestern Fennoscandia. It has been
suggested that one cause for that is the Norwegian lem
ming (Oksanen 1 988; Lundberg et al . manuscr. ) . The
Norwegian lemming is able to deplete the moss vegeta
tion quite efficiently from snowbed habitats (e.g. Kalela
1 96 1 ; Moen et al . 1 993). Depletion of moss vegetation
1 00
� 80
a; 60 > 0 (,) � 40 � � 20
1 00
80
a; 60 > 0 (,)
-� 40 -ro � 20
a)
Sopp-irC b)
LcRIC
c)
P�pC
Acta Phytogeogr. Suec. 82
OocSpC Doe SaC
Le SaC SaC
AtHC SaPalpC
creates space for small hepatics and mosses and prostrate
vascular plants . A reverse change in vegetation cover has
taken place as a consequence of experimental exclusion
of grazing on a snowbed (Virtanen et al . 1 997a; see also
Batzli et al . 1 980): the plant cover has shown signs of
succession towards moss dominance as in communities
encountered on lemming-free arctic islands (Virtanen et
al . 1 997b) . Thus, existence of copious moss vegetation in
conditions comparable to middle ( oro )arctic zones may
also depend on the absence of moss-eating lemmings.
c::J Vascular plants FrA Robust mosses FrA Other bryophytes FrA Lichens + black crust
Fig. 22a-c. Relative cover (%) of vascular plants, robust mosses, other bryophytes and lichens in generalized community series along ridge-depression topographic sequences on Spitsbergen: a) inner fjord region; b) coastal region; c) Dryas region. See text for further explanation.
7 Acknowledgements
We thank A. Hakala for help with the field work on Spitsbergen and L. Oksanen for reading an earlier version of the
manuscript. We also thank A. Elvebakk and an anonymous referee for comments. The study was fmancially supported by
the Research Council for Environment and Natural Resources of Finland and the University of Oulu.
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Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 47
Appendix 1 . Mean percentage cover of plants in community types of the Festuca ovina-Potentilla crantzii group. l - Festuca ovina-Dryas octopetala community, 2 - Festuca ovina-Potentilla crantzii type, 3 - Festuca ovina-Dryas octopetala-Hylocomium community, 4 -Festuca ovina-Saussurea alpina-Sanionia community, 5 - ]uncus trifidus-Cassiope tetragona type, mossy variant. The frequencies of the taxa are indicated as follows: bold, f >66.7, underlined, 33.3<f:;66.7, normal text, f�33 .3 .
A lchemilla sp.
Antennaria alpina
Antennaria canescens
Anthoxanthum odoratum
A rabis alpina
Bartsia alpina
Bistorta vivipara
Calamagrostis lapponica
Carex bigelowii
Carex rupestris
Carex vaginata
Cassiope tetragona
Cerastium alpinum
Draba daurica
Dryas octopetala
Empetrum nigrum ssp. hermaphr.
Euphrasia frigida
Festuca ovina
Hieracium alpinum
Linnaea borealis
Luzula multiflora ssp. frigida
Luzula spicata
Oxyria digyna
Phyllodoce caerulea
Poa alpina
Potentilla crantzii
Rhodiola rosea
Salix hastata
Salix polaris
Salix reticulata
Saussurea alpina
Saxifraga cernua
Saxifraga cespitosa
Saxifraga nivalis
Saxifraga oppositifolia
Selaginella selaginoides
Silene acaulis
Solidago virgaurea
Thalictrum alpinum
Trisetum spicatum
Vaccinium uliginosum
Vaccinium vitis-idaea
Viola biflora
0.9
0.3
0. 1
0. 1
0.4
0. 1
li
1 .0
2 .8
0. 1
0. 1
1 . 8
0.4
2
0.3
1 .8
0.5
4.6 0.5
1 9.7 3.9
0.9
0.4 0.3
15.4 30.0 0.3 0.5
0.3
0.3
2.3
lA 0.0
1 .8
1 .0
0. 1
lA 0.4
0.4
0.3
2.8
1 . 1
1 .9
0. 1
l.J. 2.6
1 .8
0.5
0.3
1 . 8
0.3
2.5
0.3
0.8
0.3
3.5
2.3
2.0
0.3
0.3
4.0 2.5
3
0.2
0.2
0.2
6.6
4
2.9
6.0
1 .3 2.9
4.5 1 2.0
5
0.3
2.8
3.0 0.3
6.4 0.4 0.3
0.4 0.4 15.5 0.6 1 1 .7
9.3 5.8
24.8 1 2.0 1 1 .1 0.3
1 0.3 0.4 4.4
0.2
0.4
9.3
u 0.2
2.,_Q 9.3 3 .2
0.4
0.4
0.2
1 .5
.Ll
4.7
9.1
2.9
3.4
0.4
3.8 0.3
0.3
0.6
0.3
6.7
0.3
8 .8
6.4 23.8 2.8
Additional species, occurring only in one cluster with a low frequency.
Andreaea rupestris
Bartramia ithyphylla
Dicranoweisia crispula
Dicranum fuscescens
Dicranum scoparium
Distichium capillaceum
Hylocomium splendens var. a/ask.
Mnium blyttii
Pleurozium schreberi
Pohlia cruda
Pohlia spp.
Polytrichastrum alpinum
Polytrichumjuniperinum
Rhytidium rugosum
Sanionia uncinata
Schistidium sp.
Anastrophyllum minutum
Barbilophozia floe rkei
Barbilophozia hatcheri
Gymnomitrion concinnatum
Tritomaria quinquedentata
Alectoria ochroleuca
Cetraria ericetorum
Cetraria islandica
Cladina arbuscula s p. mitis
Cladina rangiferina
Cladonia chlorophaea
Cladonia gracilis
Cladonia pocillum
Cladonia pyxidata
Cladonia uncia/is
Flavocetraria cucullata
Flavocetraria nivalis
Peltigera malacea
Stereocaulon alpinum
Thamnolia vermicularis
Total
0.3
0. 1
0. 1
0.2
0.6
0. 1
0.4
0. 1
0.3
0. 1
0.3
0.3
0. 1
l.J. 0.3
0.5
0. 1
0. 1
0.4
0. 1
0.6
1 . 1
0. 1
0. 1
0.3
2
0.3
0.3
3
0.2
u
4
0.4
5
0.9 0.3
0.8 1 1 .2 0.3
2.0 26.6 .!L2. 13.2
0.3
7.2
1 . 8
0.3
1 .3 0.3
0.5
0.3
0.3
1 .3
0.2 0.4 0.3
0.2
1 .5
0.2
0.2
0.2
0.8
0.2
0.2
1 .0 0.2
0.2
0.4
1 .3
6.8
1 .3 0.4
1 .3
0.3
0.3
0.9
2.2
0.3
2.5
0.9
0.3
5.1
0.6
0.6
0.3
0.3
0.3
0.6
0.9 0.6
0.3
0.3
0.3
90.7 1 87.0 1 80.3 1 29.9 1 34. 1
1 : Antennaria dioica ( 1 .9), Campanula rotundifolia (0.4), Deschampsiaflexuosa ( 1 .8), Geranium sylvaticum (0. 1 ), Juniperus communis (3.5), Lychnis alpina (0. 1 ),
Minuartia biflora (0. 1 ), Veronica fruticans (0.4), Abietinella abietina (0. 1 ), Bryum argenteum (0. 1 ), Lescurea saxicola (0. 1 ), Pseudoleskeella tectorum (0. 1 ),
Saelania glaucescens (0. 1 ), Tortula norvegica (0. 1 ), Preissia quadrata (0. 1 ), Ptilidium ciliare (0. 1 ), A lectoria nigricans (0.9), Bryocaulon divergens (0. 1 ),
Hypogymnia physodes (0. 1 ) , Ochrolechiafrigida (2. 1 ), Sphaerophorus globosus (0. 1 )
2 : Equisetum variegatum (0.3), Erigeron uniflorus (0.3), Solorina crocea (0.3)
3 : A rctostaphylos alpina (3 .0), Astragalus alpinus (3.0), Nephroma expallidum (0.2)
4 : Cladonia ecmocyna (0.4)
5: }uncus trifidus (2.2), Salix herbacea ( 1 7.8) , Cladina stellaris (0.3), Solorina saccata (0.3)
Acta Phytogeogr. Suec. 82
48 R. Virtanen & S. Eurola
Appendix 2. Mean percentage cover of plants in community types of the Alectoria group. 1 - Dryas octopetala-Carex rupestris type, 2,3 - Empetrum-Cassiope tetragona-Alectoria type, 4 - Gymnomitrion type. For frequencies, see Appendix 1 .
2 3 4 2 3 4
Betula nana 4.0 6.4 Gymnomitrion concinnatum 5.5 0.7
Calamagrostis lapponica <0. 1 0.2 Gymnomitrion corallioides 0.2 2.4 22.0 Carex rupestris 5.9 Hepaticae indet. 0.2 0.5
Cassiope tetragona .LQ 22.5 .LQ 0.7 Lophozia spp. 0.5 0.7
Dryas octopetala 32.4 0.4 Ptilidium ciliare 0.2 0.7
Empetrum nigrum ssp. hermaphr. 1 . 1 8.8 7.9 Tetralophozia setiformis 0. 1 3.0 <0. 1
Festuca ovina 9.7 <0. 1 0.2
Hieracium alpinum s. !at. 0.2 A lectoria nigricans 1 .5 0.6 1.7 1 .3 Huperzia se/ago 0. 1 <0. 1 A tectoria ochroleuca 0.6 0.3 0.6 1 .3 Luzula arcuata ssp. confusa 0. 1 .LQ 0.9 Bryocaulon divergens 0.8 0.7 2.3 Luzula spicata 0. 1 Q,1 Cetraria aculeata 0. 1 Q,1 Salix herbacea 0.9 1 .4 Cetraria ericetorum 1.4 0. 1 0.6 1 .3 Salix polaris 1 .2 L8 Cetraria islandica 0.2 u Saxifraga oppositifolia OA Cetraria islandica ssp. crispiformis 0.2 0.4
Silene acaulis 0� <0. 1 Cetraria nigricans Q,1 0.3 0.5 0.5
Vaccinium vitis-idaea 1 .8 0.4 3.6 Cetrariella delisei <0. 1 Q,1 Cladina arbuscula ssp. mitis 0.5 0.6 0.5
Dicranum elongatum 0.5 2.8 Cladina rangiferina 0.2 0.5 Q,1 0.2
Die ranum fuscescens 0. 1 1 .3 li Cladina stygia 0.3 0.4
Dicranum scoparium 0.2 <0. 1 2.9 Cladonia amaurocraea <0. 1 0. 1 Q,1 Dicranum sp. 0,1 0.4 Cladonia cervicornis <0. 1 0.2
Ditrichum jlexicaule 0,1 Cladonia chlorophaea 0.2 0.7
Pogonatum dentatum 0.2 Q,1 Cladonia coccifera <0. 1 Q,1 0.3 0.9 Pogonatum urnigerum Q,1 Cladonia gracilis 0.3 0.2 1.1 Pohlia spp. 0,2 0.3 Q,1 0.7 Cladonia pocillum 0.5
Polytrichastrum alpinum 0. 1 Q,1 Cladonia uncia/is 0. 1 Q,1 0.9 Polytrichastrum sexangulare Q,1 Crustaceous black 5.5 Polytrichum hyperboreum Q,1 Crustaceous lichens 2.J. Polytrichum juniperinum <0. 1 0.6 0.5 Flavocetraria cucullata 1.0 0.3 1 .2 1 . 1 Polytrichum piliferum 0.2 0.5 2.0 Flavocetraria nivalis 3.7 1 0.0 10.3 1 .3 Polytrichum sp. 0.2 0.4 Ochrolechia frigida 2.9 3.0 8.0 5.9 Racomitrium lanuginosum 0.5 2.6 <0. 1 0.7 Pertusaria sp. 1 .3 Rhytidium rugosum O,Q Psoroma hypnorum 0. 1 0.2
Tortella fragilis 0,1 Solorina crocea Q,1 0.5
Sphaerophorus fragilis 0. 1 0 .2
Anastrophyllum minutum Q,1 0.2 0.5 Sphaerophorus globosus 1 .0 0.5 1 .5 3.4 Barbilophozia spp. 0. 1 0.7 Stereocaulon alpinum 0.3 <0. 1 0.2
Cephalozia sp. 0. 1 <0. 1 0.2 Thamnolia vermicularis 0.3 0.3 1.3 Diplophyllum taxifolium 0. 1 <0. 1 0.2
Gymnomitrion apiculatum 0.5 0.2 0.2 Total 85.6 60.5 53 .7 92.5
Additional species, occurring only in one cluster with a low frequency.
1 : Antennaria alpina (0.2), Carex glacialis (0.3), Cerastium alpinum (0.2), Festuca vivipara (0.2), Juniperus communis (4.4), Salix hastata ( 1 .3), Saxifraga nivalis
(0.3), Vaccinium uliginosum (0.2), Aulacomnium turgidum (0. 1 ), Bartramia ithyphylla (0.2), Cnestrum schisti (0.2), Distichium capillaceum (<0. 1 ), Encalypta
alpina (0.2), Hylocomium splendens var. alaskanum (0.2), Hypnum bambergeri (0.2), Hypnum revolutum (0. 1 ), Mnium marginatum (0.2), Plagiobryum zieri (0.2),
Plagiothecium sp. (0.2), Pleurozium schreberi (0.2), Racomitrium canescens (0.2), Saelania glaucescens (0.2), Timmia austriaca (0.2), Tortella tortuosa ( <0. 1 ), Barbilophozia hatcheri (0.2), Cladonia pyxidata (0.3), Peltigera apthosa (0.2), Solorina saccata (0.2)
2 : Pedicularis lapponica ( <0. 1 ), Phyllodoce caerulea ( <0. 1 ), Bistorta vivipara ( <0. 1 ), Pohlia nutans ( <0. 1 )
4 : A rctostaphylos alpina (0.4), Trisetum spicatum (0.2), Dicranoweisia crispula (0.4), Hypogymnia bitteri (0.7), Parmelia omphalodes (0.2), Stereocaulon sp. (0.2)
Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 49
Appendix 3. Mean percentage cover of plants in community types of the ]uncus trifidus-Cassiope tetragona group. 1 ,3 - Empetrum-Cassiope tetragona type, 2 - Empetrum-Flavocetraria nivalis type, 4-8 - ]uncus trifidus-Cassiope tetragona type, 4 - Carex bigelowii variant, 5,6 - typical variants, 7 - graminoid variant, 8 - Polytrichum hyperboreum variant. For frequencies, see Appendix 1 .
2 4 6 7
Antennaria alpina . 0.2 M Antennaria canescens 0. 1 0.7
Anthoxanthum odoratum u Betula nana 2 1.7 u 0.2 0.3
Bistorta vivipara 0.4 0.4 0.6 Q2 M 0. 1
Calamagrostis lapponica 1 . 1 0.3 u M 0.3 0.3
Carex bigelowii 0.4 3.9 2.2 7.9 M 2.5 0.6 b.Q Carex vaginata 0. 1 <0. 1 0.2
Cassiope hypnoides 0.2 0.3 0.4 .LQ Cassiope tetragona 2 1 .4 7.2 1 8.2 1.4,2 0.2 0.9 <0. 1 6.6
Empetrum nigrum sp. hermaphroditum 0. 1 6.6 42.0 1 1 .7 1 . 1 0.5
Festuca ovina 3.1 0.4 0.5 L2 7.0 1 1.2 6.9 0.2
Gnaphalium supinum 0.2 Hierochloe alpina 0. 1 <0. 1 <0. 1 0.2 .LQ 0.3 <0. 1
Huperzia se/ago Q2 0.3 <0. 1
}uncus trifidus <0. 1 u lU 2 1 .3 0.3 9.8 6.0
Luzula arcuata ssp. confusa 0.3 M 1.1 M M Luzula spicata 0.4 <0. 1
Pedicularis Lapponica 0.2 0.4
Phyllodoce caerulea 0.9 1 .5 0.2 0.3 ,(U Salix herbacea 5.5 kQ .LQ L2 16.2 1 5.8 3.0 2.5
Sibbaldia procumbens 0.2 0.3 <0. 1
Solidago virgaurea 0.2 !U 0.3
Trisetum spicatum 0. 1 .u <0. 1
Vaccinium vitis-idaea 7.2 7.2 3.2 3.8 1 .9 3.1 1 . 1 1 .0
Andreaea rupestris .l.2 .LQ <0. 1 0.2 0.2 M 0.3
Aulacomnium turgidum 0. 1 Q2 Conostomum tetragonum 0.3 0.3 0.2 0.3 M <0. 1
Dicranoweisia crispula 1 . 1 0.2 0.2
Dicranum elongatum 0.2 0.3 1.1 u Dicranum juscescens 0. 1 M 0.3 1 6.5 8.9 u 0.3 <0. 1
Dicranum majus 0. 1 0.2 0.3
Dicranum scoparium 1 . 1 2.3 !1.2 1 . 1 0.5
Dicranum sp. lA 2.8 0.2 2.2 0.3
Hylocomium splendens var. alaskanum 5.9 0.2 1 .0 0.4 0. 1
Kiaeria starkei 0.9 2.8 0.3 M <0. 1
Pogonatum dentatum 1 . 1 0.2 <0. 1
Pohlia spp. !U M 0.2 0.4 M M M <0. 1
Polytrichastrum alpinum !U 1 .5 fU 4.5 <0. 1
Polytrichum commune 0.2 0.2 0.2
Polytrichum hyperboreum 0. 1 4.6
Polytrichum juniperinum !U M !!.2 0.8 kQ 4.8 <0. 1 <0. 1
Polytrichum piliferum 2. 1 3.9 <0. 1 � 0.3 5.0 0.5
Polytrichum sp. u 0.2 0.2 0.2
Racomitrium Lanuginosum 0.3 4.7 4.1 0.4 0.3 0.3
Sanionia uncinata 0.5 0.2
Anastrophyllum minutum 2.4 M 0.4 2.1 1 .3 M Anthelia juratzkana 0. 1 0.3 0.2
Barbilophozia jloerkei 0. 1 <0. 1 u <0. 1
Barbilophozia hatcheri 0.4 !U 0.3
Barbilophozia kunzeana 0. 1 0.3 0.2 0.3
Barbilophozia quadriloba 0.3 M 0.2 0.2
Barbilophozia sp. 0. 1 0.2 0.2 0.4 0.3
Blepharostoma trichophyllum 0.3 0.2 0.2 0.2 0.6 Cephalozia spp. Q2 0.2 0.9 <0. 1
Diplophyllum taxifolium 2.2 0.3 0.3
Gymnomitrion concinnatum 0.3 2.8 2.2 0. 1
Acta Phytogeogr. Suec. 82
50 R. Virtanen & S. Eurola
App. 3, continued.
Gymnomitrion corallioides
Lophozia spp.
Ptilidium ciliare
Tritomaria quinquedentata
Alectoria nigricans
Alectoria ochroleuca
Bryocaulon divergens
Cetraria ericetorum
Cetraria islandica
Cetraria islandica ssp. crispiformis
Cetraria nigricans
Cetrariella delisei
Cladina arbuscula ssp. mitis
Cladina rangiferina
Cladina stygia
Cladonia amaurocraea
Cladonia bellidiflora
Cladonia coccifera
Cladonia crispata
Cladonia gracilis
Cladonia macrophylla
Cladonia merochlorophaea
Cladonia pyxidata
Cladonia squamosa
Cladonia subfurcata
Cladonia sulphurina
Cladonia uncialis
Flavocetraria cucullata
Flavocetraria nivalis
Melanelia hepatizon
Nephroma arcticum
Ochrolechia frigida
Pertusaria spp.
Solorina crocea
Sphaerophorus globosus
Stereocaulon alpinum
Stereocaulon paschale
Stereocaulon spp.
Thamnolia vermicularis
Total
2
0.4 .L1 (12_ 0.5 0.4
0. 1 0.3 u 0.9
0.3 0.8 <0. 1
0. 1 0.8 0.2
0.3 Q2 <0. 1
1 .6 1 .7 2. 1
0.4 <0. 1
Q2 Q2 0.9 0.2
0.4 0.4
1.9 .u 0.7
.3.,2 0.2 0.3
M 0.3
0.8 0.3 0.2
0.9 Q]_ 0.4
1 .9
2.0 1 .2 0.9
0.4 0.2
0. 1 0.2
0.3 <0. 1
0.3 0.2
0.4 0.2
0. 1
1 . 1 1.0 0.8
1 .6 1 .2 4.4
0.4 3.4 0.5
Q...2 Q2 0. 1 0.2
1 .0 .L.Q 0. 1 lA 1 . 1 1,2 0.4 1 .1 0.9
0. 1 0.3 0.4
4.5 <0. 1
0.3 Q2 0.4 Q2 0.5
1 1 3.9 1 1 9.6 1 08.7
Additional species, occurring only in one or two clusters with a low frequency.
4 6 7 8
0.2
0.4 0.9 2.2 0.3 <0. 1
.L.2 13.9 0.3
0.2 0.2 0.3
0.2 0.3 M 0.4 0.2
0.2
2.3 12.6 3. 1 M 5.2
0.2
1 .9 0.9 1.& :i,2 M 0.2 0.2
0.2 0.2 0.6 M 3.8
2.1 1 . 1 0.6 u 0.4
0.3
0.2 0.2
0.4 M <0. 1 <0. 1
0.2 (12_ <0. 1 !U 1 .0 1 . 1 1 .3 0.4 0.3
0.4 0.3
2.3 2.2 0.6 0.3 0.3
Q2 0.3
0.2 0.3 0.3
0.2 0.2 <0. 1
0.2 0.3
0.2 M 0.3 0.2
0.2 0.2 !U 0.8 1 . 1 0.9 0.4 QJ. 1 .0 0.3 0.6 0.3 <0. 1
0.4 Q2 0.3 0.7
0.4 0.2 0.6 M M 1.& 2.5
1 .3 3.9 5.3 M 25.4
0.2 0.3
0.2 0.3
0.8 0.2 0.3 <0. 1
4.7 ti 0.4 <0. 1
0.2 0.3
1 .5 0.3 <0. 1
0.8 M 0.3 !U
1 22.7 1 1 5 .3 98.4 50.6 73.9
I : Cardamine bellidifolia (0. 1 ), Dryas octopetala (0. 1 ), Festuca vi vi para (0. 1 ), Linnaea borealis ( 1 .9), Oxyria digyna (0. 1 ), Salix hastata ( 1 .9), Salix polaris (0.9), Saussurea
alpina (0.3), Saxifraga tenuis (0.3), Vaccinium myrtillus (0. 1 ), Viola biflora (0.4), Bartramia ithyphylla (0.4), Pogonatum umigerum ( 1 .8), Polytrichastrum sexangulare (0. 1 ),
Scapania sp. (0. 1 ), Sphagnum girgensohnii (7 . 1 ), Cladina stellaris ( 1 .9), Cladonia ecmocyna (0. 1 ), Cladonia pocillum (0.3), Peltigera scab rosa (0. 1 )
2 : Rubus chamaemorus (0.2), Racomitrium microcarpon (0.2), Scapania sp. (0.2), Cladoniafimbriata (0.2), Nephroma expallidum (0.2), Peltigera apthosa (0.2)
3: Dryas octopetala (0.9), Linnaea borealis (0.2), Vaccinium uliginosum ( 1 . 1 ), Pleurozium schreberi (0.2), Sphagnum girgensohnii (3.0), Cetraria aculeata ( <0. 1 ), Nephroma
expallidum ( <0. 1 ), Peltigera apthosa (0.2), Psoroma hypnorum ( <0. 1 )
4 : Festuca vivipara (0.2), Oxyria digyna (0.4), Pleurozium schreberi (0.3), Rubus chamaemorus (0.2), Salix polaris (5 .8), Trientalis europaea (0.2)
5 : Pyrola minor (0.2), Trientalis europaea (0.2), Vaccinium myrtillus (0.2), Polytrichastrum sexangulare (0.2), Racomitrium microcarpon (0.2), Peltigera scabrosa (0.2)
6: Cardamine bellidifolia (0.3), Lycopodium clavatum (0.3), Ceratodon purpureus (0.3)
7: Agrostis mertensii (0.3), Erigeron uniflorus ( <0. 1 ), Minuartia biflora ( <0. 1 ), Silene acaulis (0.8), Cladonia deformis ( <0. 1 ), Cladoniafimbriata ( <0. 1 ), Peltigera rufescens
( <0. 1 ), Psoroma hypnorum ( <0. 1 )
8 : Silene acaulis (0.6), Vaccinium uliginosum ( <0. 1 ), Cetraria aculeata ( <0. 1 ), Cladonia deform is ( <0. 1 ), Cladonia fimbriata ( <0. 1 ), crustaceous black (4.3)
Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 5 1
Appendix 4. Mean percentage cover of plants in community types of the Salix herbacea group. 1 - Salix herbacea-Kiaeria type, 2 - Salix herbacea-Cassiope hypnoides type, 3 - Salix herbacea-Kiaeria type, Carex bigelowii variant, 4 - Carex bigelowii type, 5,6 - Cassiope hypnoides-Juncus trifidus type, 7 - Carex bigelowii-Salix polaris type, 8 - ]uncus trifidus-Cassiope tetragona type, Cetrariella delisei variant, 9 - Trisetum spicatum-Sanionia type. For frequencies, see Appendix 1 .
Agrosris mertensii
Antennaria alpina
Anthoxanthum odoratum
Bistorta vivipara
Cardamine bellidifolia
Carex bigelowii
Carex lachenalii
Cassiope hypnoides
Cassiope tetragona
Deschampsia flexuosa
Diphasiastrum alpinum
Erigeron uniflorus
Festuca ovina
Gnaphalium supinum
Hieracium sp.
Huperzia selago
}uncus biglumis
}uncus trifidus
Luzula arcuata ssp. confusa
Luzula spicata
Oxyria digyna
Phyllodoce caerulea
Poa alpina
Potentilla crantzii
Ranunculus acris
Ranunculus glacialis
Ranunculus nivalis
Rhodiola rosea
Salix herbacea
Salix polaris
Salix sp. Saussurea alpina
Sibbaldia procumbens
Silene acaulis
Taraxacum sp.
Trisetum spicatum
Vaccinium vitis-idaea
Vahlodea atropurpurea
Veronica alpina
Viola bijlora
Andreaea rupestris
Bryum sp.
Conostomum tetragonum
Dicranoweisia crispula
Die ranum fuscescens
Dicranum scoparium
Hylocomium splendens var. alaskanum
Kiaeria starkei
Mnium blyttii
Oligotrichum hercynicum
Pogonatum dentatum
Pogonatum urnigerum
Pohlia cruda
Pohlia spp.
Polytrichastrum alpinum
Polytrichastrum sexangulare
Polytrichum commune
Polytrichum hyperboreum
Polytrichum juniperinum
Polytrichum piliferurn
Polytrichum sp.
2.2
1 .2
6.5
1 .2
1 .8
<0. 1
<0. 1
<0. 1
28.0
1 2. 1
Q.j_ <0. 1
<0. 1
3.3
26.2
<0. 1
0.7
0.3
4.2
2
0. 1
1 8.2
7.8
0. 1
0.9
0. 1
0.3
0.3
0. 1
0. 1
0. 1
13.8
0. 1
1 .5
0.3
0.9
1 .9
0. 1
0. 1
0.8
1 .8
u 1 .8
0.3
5.4
4.6
0.6
0.9
22.9
<0. 1
0.5
<0. 1
0.6
0.9
1 .0
<0. 1
<0. 1
29.2
0.3
7.3
0.3
<0. 1
1 . 1
0.3
0.3
<0. 1
ti
4
1 . 1
0.4
13.4
8.4
0.4
<0. 1
1 .8
0. 1
<0. 1
0. 1
0.5
0.3
1 .0
0. 1
0. 1
2.8
l . l
0.3
0.3
0.4
2.0
0. 1
u <0. 1
0.4
0.3
2. 1
0. 1
0.7
0.3
<0. 1
<0. 1
0.5
<0. 1
0.3
<0. 1
5 .2
0.3
1 .8
0.2
<0. 1
0.4
6.,2 2.3
0.3
<0. 1
0.3
<0. 1
<0. 1
0.9
0.4
<0. 1
<0. 1
0.5
<0. 1
<0. 1
<0. 1
<0. 1
<0. 1
<0. 1
0.2
<0. 1
<0. 1
0.4
0. 1
0.2
0.5
0.2
6
0.2
D <0. 1
19.5
0.2
<0. 1
<0. 1
7.1
<0. 1
<0. 1
1 .9
<0. 1
0.2
<0. 1
1 .0
0.5
1 .0
<0. 1
7
0.5
!U <0. 1
1 .8
8.5
!U 6.6
!U 0. 1
<0. 1
<0. 1
4.2
!U <0. 1
!U <0. 1
0.7
0.4
0.2
<0. 1
<0. 1
<0. 1
<0. 1
!U
<0. 1
0.3
8.2
0.4
<0. 1
0.3
0.7
<0. 1
0. 1
<0. 1
0.2
M <0. 1
0.2
<0. 1
<0. 1
0.3
<0. 1
0.2
0.2
<0. 1
0.5
2.4
0.3
8
0. 1
0.5
2.0
27.5
0.5
0. 1
5 .0
1 .0
0.5
1 .0
2.5
0.5
1 .5
0. 1
2.6
0.3
0.5
0. 1
0. 1
0. 1
0.6
9
0.3
<0. 1
7.4
<0. 1
2.0
9.2
2.0
0.2
4.8
0. 1
0.3
<0. 1
1.1 0.3
3.7
2.2
0.3
2.0
0.6
<0. I 1 .4
!U 0.2
1 . 1
<0. 1
0. 1
0.3
0.5
0.4
1 .0
u 0.6
<0. 1
M
0.3
1 .8
0.8
3 .3
0 .7
Acta Phytogeogr. Suec. 82
52 R. Virtanen & S. Eurola
App. 4, continued.
Racomitrium microcarpon
Sanionia uncinata
Anastrophyllum minutum
Anthelia juratzknna
Barbilophozia floerkei
Barbilophozia hatcheri
Blepharostoma trichophyllum
Cephalozia spp.
Cephaloziella sp.
Diplophyllum taxifolium
Gymnomitrion apiculatum
Gymnomitrion concinnatum
Lophozia sudetica
Lophozia wentzelii
Lophozia spp.
Marsupella brevissima
Marsupella condensata
Pleurocladula albescens
Ptilidium ciliare
Tritomaria quinquedencata
Cetraria ericetorum
Cetraria islandica
Cetraria islandica ssp. crispiformis
Cetrariella delisei
Cladina arbuscula ssp. mitis
Cladonia bellidifolia
Cladonia coccifera
C/adonia ecmocyna
Cladonia gracilis
Cladonia macrophylla
Cladonia pocillum
Cladonia pyxidata
Cladonia subfurcata
Cladonia uncia/is
Crustaceous black Crustaceous lichens
Ochrolechia frigida
Pertusaria dactylina
Solorina crocea
Stereocaulon alpinum
Stereocaulon pp.
Total
0.8
0.9
J.,2 8.9
2 3 4
Q,2 0.3 0.3
u J.,2 0.4
!1..8 4.6
0. 1
0. 1 0.3
0.3 0.3
Q,2 0. 1 {U
0.3 0.3
2.0 Q,2 3.5
0.2
0.3
5.5 2.3 J.&
0.5 0.9
0. 1 0.3
0.3 <0. 1
0.3 12 {U 0. 1
0.8 2.6 0.3 0.3 0.5 2.3
0.7 0.8 0.9
0.4 0.6
1 .0 0.8
0.3 0.3 Q2 0.5 1 .0 M
0.3
0.3
Q,1 <0. 1 0.9 M
0.6
0.2
ll Q,1 0.3
QJ. 0.3 Q,2 Q,1 M
1 34.7 9 1 .3 1 06.0
Additional species, occurring only in one or two clusters with a low frequency.
6 7
<0. 1 <0. 1
<0. 1 M
M 4.9 <0. 1
<0. 1 <0. 1
<0. 1
Q.j_ 0.2 <0. 1
0.4 1 . 1 0. 1 <0. 1
<0. 1 0.3 <0. 1
0. 1 <0. 1
0. 1 <0. 1
5.5 25.0 1 1 .1 0.4
0.3 u 2.0 <0. 1
0.2
Q,2 0.2
0. 1 2.2 0.6 <0. 1
0.5 !1..8 1 .0 1 .9
0.3 <0. 1
0.4 0.2
u D 2.7
<0. 1 u 0.3
0.7 Q,2 .u Q,2 4.3 1 .0 8.2 3.2
1 .5 2.0 <0. 1 1 2.8
0.2 <0. 1 <0. 1
0.5 0.4 !1..8 0.2
<0. 1 Q2 0.7 0.3 <0. 1 M
<0. 1 <0. 1
<0. 1 0.3 0.2 <0. 1 <0. 1
0.3 0.3 0.2 0.2 0.2 0.8 1 . 1
2.5 2..8 2J1 fL:1 1 .7 .u u
3.4 3.6 13.2 1 1.9
<0. 1 <0. 1 0. 1
0.3 QJ. Q,1 0.2 QJ. 0.3
M 0.2 0.2 <0. 1
74.6 76.6 95.6 86.4
I : Luzula multiflora ssp. frigida (0.3), Poa alpigena ( <0. 1 ), Diphysciumfoliosum (0.2), Moerchia blyttii ( <0. 1 )
8 9
15.3
0. 1 {U 0.3
0. 1 2.& QJ.
0.2
0.3
0. 1
0.5 <0. 1
0.3
0.5
2.5 u
20.0 <0. 1
1 .6 .L.Q
0.3 QJ. 0.3 0.2 0.3 QJ.
0.3
0.3 0. 1
0.3
<0. 1
0.3 0.6
16.5 D <0. 1
QJ. 0. 1 0.8
92. 1 87.0
2: Calamagrostis Lapponica (0.9), Carex vaginata (0. 1 ), Vaccinium myrtillus (0. 1 ), Dicranum elongatum (2.7), C/adonia crispata (0. 1 ), Cladonia turgida (0. 1 ), Peltigera
scabrosa (0.2), Stereocaulon paschale (0.9)
3: Calamagrostis lapponica (0.3), Diphysciumfoliosum (0. 1 ), Melanelia hepatizon ( 1 .8), Peltigera scabrosa (0.3)
4: Antennaria canescens (0. 1 ), Diapensia lapponica (0. 1 ), Racomitrium lanuginosum (0. 1 ), Sphagnum fimbriatum (0. 1 ), Thamnolia vermicularis (0. 1 )
5 : Erigeron humilis (0. 1 ) , Pohlia drummondii ( <0. 1 ) , Cladonia cervicornis ( <0. 1 ), Cladonia deformis (0. 1 ), Flavocetraria nivalis ( <0. 1 )
6 : Racomitrium lanuginosum ( 1 .0), Sphagnum fimbriatum (0. 1 ) , Cladonia cervicornis (0. 1 ) , Flavocetraria nivalis ( <0. 1 )
7 : Antennaria canescens (<0. 1 ), Antennaria porsildii (<0. 1 ), Cerastium arcticum (<0. 1 ), Erigeron humilis (<0. 1 ), Minuartia biflora (<0. 1 ), Poa alpigena (<0. 1 ), Thalictrum
alpinum ( <0. 1 ), Bartramia ithyphylla ( <0. 1 ), Distichium capillaceum ( <0. 1 ), Pohlia drummondii ( <0. 1 ), Cladina rangiferina ( <0. 1 ), Cladonia deformis ( <0. 1 ), Cladonia
fimbriata (<0. 1 ), Flavocetraria cucullata (0. 1 ), Melanelia hepatizon (<0. 1 ), Nephroma expallidum (<0. 1 )
8 : Antennaria lanata (0.5), Cerastium arctic urn (0.5), Empetrum nigrum ssp. hermaphroditum (0. 1 ) , Thamnolia vermicularis (0. 1 )
9: Carex vaginata (0. 1 ), Cerastium cerastoides ( <0. 1 ), Erigeron humilis (0. 1 ), Minuartia biflora (0. 1 ), Aulacomnium turgidum (0.3), Bartramia ithyphylla (0.3), Hylocomiastrum
pyrenaicum (0.3), Nephroma expallidum (0.6), Peltigera leucophlebia (0.6), Peltigera malacea (0.3), Peltigera rufescens ( <0. 1 )
Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 53
Appendix 5. Mean percentage cover of plants in community types of the Ranunculus glacialis group. 1 - Anthelia-Polytrichastrum sexangulare type, 2 - Koenigia islandica-Phippsia algida community. For frequencies, see Appendix 1 .
2 2
Cardamine bellidifolia !U Philonotis sp. 2.5
Carex bigelowii 0. 1 0. 1 Pohlia drummondii QJ. Carex lachenalii !U 0. 1 Pohlia spp. .Q2 1 .8
Cassiope hypnoides 1 .4 Polytrichastrum alpinum 0.2 0.3
Cerastium arcticum <0. 1 Polytrichastrum sexangulare 7.9
Cerastium cerastoides 1 .8 Sanionia nivalis 4.0
Epilobium anagallidifolium <0. 1 1 .0 Tortula norvegica <0. 1
Equisetum arvense 4.0 Warnstorfia exannulata 10. 1
Gnaphalium supinum 1 .2
}uncus biglumis 0.4 Anthelia juratzkana 18.5 9.0
Koenigia islandica 5.1 Barbilophozia jloerkei 0. 1
Luzula arcuata ssp. confusa Q2 Cephalozia sp. 0.2 1 .5
Oxyria digyna 0. 1 Gymnomitrion apiculatum <0. 1
Phippsia algida 0. 1 Gymnomitrion concinnatum 9.:1 Phleum alpinum 1 .0 Gymnomitrion corallioides 6.2
Poa alpina !U. 0. 1 Lophozia sp. 1 . 1
Ranunculus acris 0. 1 Marsupella brevissima 0. 1
Ranunculus glacialis 0.3 Pleurocladula albescens .Q2 0.8
Ranunculus nivalis 0.4 Preissia quadrata <0. 1
Ranunculus pygmaeus <0. 1
Sagina nivalis <0. 1 Cetraria ericetorum <0. 1
Sali.x herbacea 1 .5 Cetraria islandica 0.9
Sali.x polaris 0.3 Cetraria islandica ssp. crispiformis 0.2
Saxifraga cernua 0. 1 Cetrariella delisei Q,2 0. 1
Saxifraga oppositifolia <0. 1 Cladina arbuscula ssp. mitis 0.4
Saxifraga stellaris 3.0 Cladonia coccifera 0.3
Saxifraga tenuis <0. 1 Cladonia ecmocyna <0. 1
Sibbaldia procumbens 2.,Q Cladonia gracilis !U Silene acaulis <0. 1 Cladonia pocillum 0. 1
Trisetum spicatum 0.3 Cladonia pyxidata 0. 1
Cladonia uncialis 0. 1
Andreaea rupestris Q,2 Crustaceous black 14.0
Bartramia ithyphylla <0. 1 0.5 Crustacous lichens 0. 1
Brachythecium sp. <0. 1 Ochrolechia frigida 0.4
Bryum sp. 8.5 Pertusaria sp. 0.4
Conostomum tetragonum 0.3 0. 1 Solorina crocea !U. Dicranoweisia crispula <0. 1 Stereocaulon rivulorum 0. 1
Kiaeria starkei 4,.0 Stereocaulon sp. M Oncophorus wahlenbergii 1 .5
Total 9 1 .7 59.3
Acta Phytogeogr. Suec. 82
54 R. Virtanen & S. Eurola
Appendix 6. Mean percentage cover of plants in community types of the Saxifraga oppositifolia group. 1 - Salix polaris-Silene acaulis type, 2 - Saxifraga oppositifolia-Ranunculus sulphureus type, 3 - Dryas octopetala-Cassiope tetragona type. For frequencies, see Appendix 1 .
2 3 2
Arabis alpina 0.3 <0. 1 Mnium blyttii <0. 1 0.3 0.3
Bistorta vivipara 0.5 1 .3 Platydictya jungermannioides <0. 1 <0. 1
Cardamine bellidifolia <0. 1 <0. 1 Pogonatum umigerum <0. 1 <0. 1
Carex bigelowii Q,2 0.3 <0. 1 Pohlia cruda 0.2 <0. 1 0.2
Carex lachenalii 1 . 1 Pohlia spp. tU <0. 1 <0. 1
Cassiope hypnoides 2.6 M 0.3 Polytrichastrum alpinum <0. 1 0.2
Cassiope tetragona M 0.7 1 1 .7 Polytrichastrum sexangulare 0. 1 0.8
Cerastium arcticum 0.2 0.2 <0. 1 Polytrichum juniperinum <0. 1 <0. 1 <0. 1
Draba fladnizensis <0. 1 <0. 1 0.2 Sanionia uncinata !U <0. 1 <0. 1
Dryas ocropetala 0.2 3.2 36.7 Tayloria froelichiana <0. 1
Equisetum variegatum Q,2 Timmia austriaca 0.6
Erigeron humilis <0. 1 0.2 Tortella fragilis !U 3.3 0.3
Erigeron uniflorus 0.3 <0. 1 <0. 1 Tortula norvegica 0.2
Festuca ovina 0.4 0.3 0.4
Huperzia se/ago !U <0. 1 Anastrophyllum minutum 0.7 <0. 1 0.2
Luzula arcuata ssp. confusa 0.3 !U Anthelia juratzkana 1 .3 0.6 <0. 1
Luzula spicata <0. 1 <0. 1 <0. 1 Barbilophozia hatcheri 0.2 <0. 1
Oxyria digyna 0.3 <0. 1 Barbilophozia kunzeana 0.3 <0. 1
Poa alpigena <0. 1 <0. 1 Blepharostoma trichophyllum tU 0.2 0.2
Poa alpina 0.5 0.3 Preissia quadrata 0.3 0.2 <0. 1
Poa arctica M Scapania sp. <0. 1 <0. 1
Ranunculus nivalis 0. 1 <0. 1 Tritomaria quinquedentata 0.4 <0. 1
Ranunculus pygmaeus <0. 1 <0. 1
Ranunculus sulphureus � Cetraria ericetorum 0.2 4.7
Sagina nivalis <0. 1 <0. 1 Cetraria islandica 0. 1 <0. 1
Salix polaris 8.0 1 .4 .L.Q Cetraria islandica ssp. crispiformis Q,2 0.2 3 .3
Salix reticulata 0.3 Q,2 0.5 Cetrariella delisei u 0.6 2. 1
Saussurea alpina <0. 1 0.3 Cladina arbuscula ssp. mitis 0.8 .L.Q 1 .4
Saxifraga oppositifolia <0. 1 2.8 0.3 Cladonia coccifera ll <0. 1
Saxifraga tenuis 0.3 ll Cladonia gracilis ll <0. 1 0.2
Sibbaldia procumbens 0.3 1 .3 Cladonia pocillum tU 0.3 Q2 Silene acaulis 3.4 2.8 <0. 1 Cladonia symphycarpa Q2 Taraxacum sp. <0. 1 <0. 1 Cladonia uncialis <0. 1 <0. 1
Thalictrum alpinum <0. 1 0.3 Crustaceous black 2.& 29.8 5.3
Veronica alpina <0. 1 <0. 1 Crustaceous lichens <0. 1 1.& Ochrolechia frigida 2.8 2.6 1 . 1
Bryum p. 0.6 Q,2 Peltigera leucophlebia <0. 1 <0. 1
Dicranum scoparium 0.2 <0. 1 1 .7 Psoroma hypnorum <0. 1 <0. 1
Dicranum sp. 0.6 <0. 1 Solorina bispora <0. 1 0.2
Distichium capillaceum 0.5 2.6 0.3 Stereocaulon alpinum <0. 1 Q2 Encalypta alpina <0. 1 <0. 1 <0. 1 Stereocaulon botryosum <0. 1 <0. 1
Fissidens osmundoides <0. 1 0.4 Stereocaulon sp. ll <0. 1
Meesia uliginosa 0.2 <0. 1
Total 39.9 69.7 77.9
Additional species, occurring only in one cluster with a low frequency.
I : Cerastium cerastoides ( <0. 1 ), Draba daurica (0.2), Equisetum arvense (0. 1 ), Minuartia biflora ( <0. 1 ), Phyllodoce caerulea ( <0. 1 ), Potentilla crantzii (0.2), Saxifraga
cespitosa (0.2), Saxifraga nivalis (0.2), Trisetum spica rum (0. 1 ), Bartramia ithyphylla (0.2), Conostomum tetragonum ( <0. 1 ), Cyrtomnium hymenophylloides ( <0. 1 ),
Distichium inclinatum (0.4), Hylocomium splendens var. alaskanum (0. 1 ), Kiaeria starkei ( <0. 1 ), Barbilophoziafloerkei (0.2), Cephalozia sp. ( <0. 1 ), Marsupella brevissima
(0. 1 ), Odontoschisma macounii ( <0. 1 ), Cladonia pyxidata (0.2), Cladonia turgida ( <0. 1 )
2 : Antennaria porsildii (0.2), Gnaphalium supinum ( <0. 1 ) , Minuartia stricta ( <0. 1 ), Dicranoweisia crispula (<0. 1 ) , Loeskypnum badium (0.4), Mnium thomsonii (<0. 1 ),
Peltigera rufescens (0. 1 ), Psora decipiens ( <0. 1 ), Stereocaulon rivulorum ( <0. 1 )
3 : Anthoxanthum odoratum ( <0. 1 ) , Carex atrofusca ( <0. I ), Dicranum elongatum (0.7), Tritomaria scitula ( <0. 1 )
Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 55
Appendix 7 . Mean percentage cover of plants in community types of the Luzula confusa group. 1 - Luzula confusa-Gymnomitrion corallioides community, 2 - Luzula confusa-Racomitrium lanuginosum community, 3 - Luzula confusa-Sanionia community. For frequencies, see Appendix 1 .
2 2 3
Alopecurus borealis <0. 1 <0. 1 Polytrichastrum alpinum 6.8 <0. 1 <0. 1
Bistorta vivipara 0.2 <0. 1 1 .0 Polytrichum juniperinum <0. 1 0.3 Cardamine bellidifolia <0. 1 3.2 Polytrichum pi life rum QJ_ Cerastium arcticum 0.4 Polytrichum strictum 0.8 <0. 1
Cochlearia groenlandica QJ_ Racomitrium canescens u 4.3 Draba alpina <0. 1 0.3 Racomitrium lanuginosum Qj_ l..U <0. 1
Draba oxycarpa <0. 1 <0. 1 Sanionia uncinata 5.9 8.4 24.2
Draba subcapitata <0. 1 <0. 1 Timmia austriaca <0. 1 <0. 1 0.7
Dryas octopetala 0.2 0.8 Tortula ruralis 1 .5 Ll Luzula arctica 0.3 Luzula arcuata ssp. confusa 1 1 .6 1 .2 1 1 .4 Anastrophyllum minutum <0. 1 <0. 1
Oxyria digyna 0.2 0.2 <0. 1 Cephaloziella arctica <0. 1 0.3
Pedicularis hirsuta QJ_ QJ_ Gymnomitrion concinnatum 2.9 <0. 1
Poa alpina <0. 1 0.5 Gymnomitrion corallioides 12.8 <0. 1
Poa arctica <0. 1 <0. 1 Ptilidium ciliare 4.3 Qj_ <0. 1
Potentilla hyparctica <0. 1 <0. 1 Tritomaria scitula 0.6 2.5
Ranunculus pygmaeus <0. 1 <0. 1
Salix polaris 1 1 . 1 5.9 9.3 Bryocaulon divergens <0. 1 <0. 1
Saxifraga cernua <0. 1 0.2 Cetraria aculeata 0.2 <0. 1 <0. 1
Saxifraga cespitosa <0. 1 0.2 0.8 Cetraria islandica !U 1J. Saxifraga hieracifolia <0. 1 <0. 1 Cetrariella delisei 10. 1 25.7 Q2 Saxifraga nivalis <0. 1 <0. 1 0.2 Cladina arbuscula ssp. mitis 0.2 2.6 QJ_ Saxifraga oppositifolia Ll 9.6 2.0 Cladonia amaurocraea <0. 1 QJ_ Silene acaulis 0.2 <0. 1 Cladonia cltlorophaea <0. 1 0.5
Stellaria Longipes coli . <0. 1 <0. 1 Cladonia coccifera QJ_ <0. 1 0.4
Cladonia ecmocyna <0. 1 <0. 1
Andreaea rupestris <0. 1 <0. 1 Cladonia gracilis 0.2 QJ_ 0.6
Aulacomnium palustre <0. 1 <0. 1 Cladonia pocillum <0. 1 0.5
Aulacomnium turgidum u 0.2 0.3 Cladonia pyxidata <0. 1 <0. 1
Barbula sp. <0. 1 0.4 Flavocetraria cucullata 0.3 0.2
Bryum sp. 1 .5 <0. 1 0.2 Flavocetraria nivalis 0.2 .L.1 Ceratodon purpureus 2.9 <0. 1 Ochrolechia frigida 7.9 5.4 1 .0
Conostomum tetragonum M <0. 1 Peltigera leucophlebia <0. 1 <0. 1
Dicranum angustum 1 .6 QJ_ 5.4 Peltigera rufescens Q2 0.4
Dicranum elongatum Q2 Psoroma hypnorum 3.,6 0.6 1 .8
Dicranum fuscescens 2. 1 1 .5 <0. 1 Rinodina turfacea 0.2 1 .7
Dicranum scoparium <0. 1 <0. 1 Solorina crocea <0. 1 <0. 1
Dicranum spadiceum <0. 1 0.3 0.2 Sphaerophorus globosus <0. 1 0.2
Distichium capillaceum 0.3 0.3 Stereocaulon alpinum 1 .4 2.2 u Hylocomium splendens var. alaskanum 4.2 Stereocaulon rivulorum 1 .4 0. 1 0.2
Hypnum revolutum 1 .4 1 .7 Stereocaulon saxatile 2 . 1 1 .7
Oncophorus wahlenbergii <0. 1 <0. 1 <0. 1 Stereocaulon vesuvianum 0.5 <0. 1
Pohlia cruda <0. 1 <0. 1 Stereocaulon sp. 0. 1 0.2
Thamnolia vermicularis QJ_ 0. 1 0.2
Total 1 1 6.2 90.6 89. 1
Additional species, occurring only in one cluster with a low frequency.
1 : Cassiope tetragona ( 10.7), Drabajladnizensis (<0. 1 ), Empetrum nigrum ssp. hermaphroditum (0. 1 ), Festuca brachyphylla (<0. 1 ), Huperzia selago (<0. 1 ), Minuartia
rubella (<0. 1 ), Pedicularis lanata ssp. dasyantha (<0. 1 ), Phippsia algida (<0. 1 ), Poa alpigena (0.3), Saxifraga hyperborea (<0. 1 ), Trisetum spicatum (<0. 1 ), B1yum
pallescens ( <0. 1 ), Kiaeria glacialis ( <0. 1 ), Polytrichum hyperboreum ( <0. 1 ), Odontoschisma macounii ( <0. 1 ), Scapania tundrae ( <0. 1 ), Tritomaria quinquedentala ( <0. 1 ),
Cetraria islandica ssp. crispiformis ( <0. 1 ), Cladonia cervicomis ( <0. 1 ), Cladonia macrophylla ( <0. 1 ), Cladonia macroceras ( <0. 1 ), Nephroma expallidum ( <0. 1 ), Peltigera
apthosa ( <0. 1 ), Stereocaulon glareosum (0.4)
2: Draba corymbosa ( <0. 1 ), Papaver dahlianum ( <0. 1 ), Ranunculus nivalis (0. 1 ), Cratoneuron sp. (0.6), Dicranum majus (0. 1 ), Alectoria nigricans ( <0. 1 ), Collema tenax
( <0. J ), Peltigera malacea ( <0. 1 ), Physconia muscigena (0. 1 )
3 : A renaria pseudofrigida ( <0. 1 ), Carex rupestris (3.3), Cerastium regelii ( <0. 1 ), Draba nivalis ( <0. 1 ), Equisetum arvense ( <0. 1 ), Hierochloe alpina (0.7), Minuartia bijlora
( <0. 1 ), Bartramia ithyphylla ( <0. 1 ), Brachythecium turgidum ( <0. 1 ), Climacium dendroides (0.2), Encalypta alpina ( <0. 1 ), Encalypta rhaptocarpa ( <0. 1 ), Hypnum vaucheri
(<O. l ), Schistidium apocarpum (<0. 1 ), Timmia norvegica (<0. 1 ), Tomentypnum nitens (<0. 1 ), Alectoria ochroleuca (<0. 1 )
Acta Phytogeogr. Suec. 82
56 R. Virtanen & S. Eurola
Appendix 8. Mean percentage cover of plants in communities of the Papaver dahlianum group. 1 - Papaver dahlianum polar desert, 2 - Papaver dahlianum-Racomitrium panschii community. For frequencies, see Appendix 1 .
Alopecurus borealis
Bistorta vivipara
Cerastium arcticum
Draba alpina
Draba arctica
Draba corymbosa
Draba nivalis
Draba norvegica
Draba oxycarpa
Draba subcapitata
Dryas octopetala
Festuca hyperborea
Festuca rubra ssp. arctica
Luzula arctica
Luzula arcuata ssp. confusa
Minuartia bijlora
Minuartia rubella
Oxyria digyna
Papaver dahlianum
Pedicularis hirsuta
Phippsia algida
Poa arctica
Potentilla hyparctica
Potentilla pulchella
Sagina nivalis
Salix polaris
Saxifraga cemua
Saxifraga cespitosa
Saxifraga flagellaris
Saxifraga nivalis
Saxifraga oppositifolia
Silene acaulis
Silene furcata
Stellaria longipes col i .
Bartramia ithyphylla
Ceratodon purpureus
Conostomum tetragonum
Cratoneuron sp.
Dicranoweisia crispula
Acta Phytogeogr. Suec. 82
0.2
Q,l
<0. 1
0.3
1 .6
0. 1
<0. 1
0.7
<0. 1
1 .6
0.2
Q,l
Q,l <0. 1
<0. 1
<0. 1
Q,l Q,l
2
<0. 1
<0. 1
0.2
<0. 1
<0. 1
<0. 1
<0. 1
<0. 1
Q,l 0.2
<0. 1
!U <0. 1
2.9
<0. 1
Q,l 0.2
0.3
Q2
0.4
<0. 1
<0. 1
0.2
4.4
<0. 1
0.7
<0. 1
0. 1
0.6
Q2 <0. 1
<0. 1
<0. 1
<0. 1
Dicranum spadiceum
Encalypta sp.
Hypnum revolutum
Hypnum vaucheri
Polytrichastrum alpinum
Polytrichum hyperboreum
Polytrichum pi life rum
Polytrichum sp.
Racomitrium canescens
Racomitrium lanuginosum
Racomitrium panschii
Sanionia uncinata
Schistidium sp.
Tortula ruralis
Gymnomitrion corallioides
Alectoria nigricans
Caloplaca sp.
Cetraria aculeata
Cetraria islandica ssp. crispiformis
Cetrariella delisei
Cetrariella fastigiata
Cladonia coccifera
Cladonia chlorophaea
Cladonia macrophylla
Cladonia pocillum
Cladonia sp.
Lecidea sp.
Nephroma expallidum
Ochrolechia frigida
Peltigera rufescens
Physconia muscigena
Psoroma hypnorum
Rinodina turfacea
Sphaerophorus globosus
Stereocaulon alpinum
Stereocaulon rivulorum
Stereocaulon sp.
Thamnolia vermicularis
Total
<0. 1
!U
<0. 1
<0. 1
<0. 1
Q,l
<0. 1
<0. 1
0.6
Q,l
<0. 1
<0. 1
<0. 1
0.2
<0. 1
Q,l <0. 1
0.3
<0. 1
Q,l 0.4
<0. 1
<0. 1
QJ. <0. 1
<0. 1
<0. 1
9.4
2
<0. 1
<0. 1
2.9
<0. 1
<0. 1
<0. 1
<0. 1
Q,2 <0. 1
4.9
<0. 1
!U. <0. 1
0.6
<0. 1
<0. 1
� 0.3
0.7
<0. 1
10.4
<0. 1
<0. 1
2&
0.4
<0. 1
<0. 1
0.2
36.7
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 57
Appendix 9. Mean percentage cover of plants in communities of the Dryas octopetala group. 1 - Dryas octopetala-Tomentypnum community, 2 - Dryas octopetala-Sanionia community, 3 - Dryas octopetala-Salix polaris community, 4 - Saxifraga oppositifoliaHypnum revolutum community. For frequencies, see Appendix 1 .
2 4 2 3 4
Alopecurus borealis 0.2 <0. 1 <0. 1 Dicranum elongatum <0. 1 <0. 1 Bistorta vivipara 4.6 4.5 1 .0 1 .2 Dicranum fuscescens 0. 1 0.8 Cardamine bellidifolia <0. 1 <0. 1 Dicranum spadiceum u <0. 1 Carex rupestris 0.3 <0. 1 Distichium capillaceum <0. 1 <0. 1 <0. 1 1.2 Cassiope tetragona 10. 1 0.2 1 1 .7 Distichium inclinatum <0. 1 <0. 1 Cerastium arcticurn 0.2 <0. 1 0.5 0.2 Ditrichurn jlexicaule Q,1 0.2 Cerastium regelii <0. 1 <0. 1 0. 1 Hylocorniurn splendens var. alaskanum 16.8 u <0. 1
Hypnum revolutum M <0. 1 b2 � Draba alpina Q,1 {ll Q,1 0.2 Polytrichastrum alpinum <0. 1 Q,1 0.2 <0. 1 Draba norvegica <0. 1 <0. 1 <0. 1 Polytrichum juniperinurn 0.5 Qd Draba subcapicata 0.2 <0. 1 <0. 1 {ll Polytrichum piliferurn 0.2 <0. 1 Dryas octopetala 16.9 23.1 15.3 1 .6 Racornitrium canescens 0.8 2.5
Equisetum scirpoides 4.5 Sanionia uncinata 0.2 29.9 5 .0 u Festuca rubra ssp. arctica <0. 1 l.J. 0.5 <0. 1 Schistidium apocarpurn 0.3 <0. 1 Festuca vivipara <0. 1 <0. 1 0. 1 Timmia austriaca Q,1 Q,1 }uncus biglumis <0. 1 <0. 1 <0. 1 Tomentypnum nitens 10.8 7.0 10.8 Luzula arctica 1 .0 {ll 0.2 <0. 1 Tortula ruralis <0. 1 M <0. 1 Luzula arcuata ssp. confusa 9.4 1 .3 0.3 2.5 Minuartia rossii <0. 1 <0. 1 Gymnornitrion corallioides u Minuartia rubella <0. 1 0.2
Oxyria digyna Qd <0.1 <0. 1 <0. 1 Buellia papillata <0. 1 2.2 Papaver dahlianum <0. 1 {ll <0. 1 {ll Cetraria aculeata <0. 1 <0. 1 Pedicularis hirsuta 0.3 0.2 <0. 1 Q,1 Cetraria islandica <0. 1 {ll Pedicularis lanata ssp. dasyantha <0. 1 gu <0. 1 Cetraria islandica ssp. crispiformis <0. 1 <0. 1 Poa alpigena Q2 0. 1 Cetrariella delisei 0. 1 <0. 1 Poa alpina 0.2 <0. 1 Cladonia chlorophaea Q,1 Poa arctica 0.3 Qd 1 . 1 0.2 Cladonia gracilis 0. 1 <0. 1 <0. 1 Potentilla hyparctica <0. 1 <0. 1 Cladonia pocilllurn Q,1 <0. 1 Sagina nivalis Q,1 <0. 1 Cladonia pyxidata <0. 1 <0. 1 <0. 1 Salix polaris 1 1 .4 1 2.8 10.5 5.3 Flavocetraria nivalis <0. 1 <0. 1 Saxifraga cemua <0. 1 <0. 1 0. 1 Q,1 Lecidea sp. <0. 1 1 .7 0.7 Saxifraga cespitosa <0. 1 <0. 1 <0. 1 0. 1 Nephroma expallidum 0.2 0.2 Saxifraga jlagellaris <0. 1 Q,1 Ochrolechia frigida 7.9 7.4 1 .7 8.7
Saxifraga nivalis <0. 1 <0. 1 <0. 1 <0. 1 Peltigera leucophlebia Qd <0. 1 Q2 Saxifraga oppositifolia 0. 1 1 .8 1 . 1 6.9 Peltigera rufescens ll 0.2 ll Silene acaulis <0. 1 0. 1 Physconia muscigena <0. 1 <0. 1 <0. 1 Si le ne furcata {ll Psororna hypnorum 2.7 l . l Silene uralensis <0. 1 <0. 1 Rin.odina turfacea Qd <0. 1 Stellaria longipes coli . 0.3 ll Q,1 <0. 1 Solorina crocea <0. 1 <0. 1
Sphaerophorus globosus <0. 1 <0. 1 Aulacomnium turgidum 5.9 0.4 (U Stereocaulon alpinum 0.8 <0. 1 2.5 Bartrarnia ithyphylla 0.2 <0. 1 Stereocaulon rivulorurn <0. 1 lJ2 u Qd Brachytheciurn turgidum <0. 1 <0. 1 Stereocaulon saxatile <0. 1 <0. 1 Bryurn pallescens <0. 1 0.2 Stereocaulon sp. 3. 1 <0. 1 Bryum spp. < 0. 1 <0. 1 <0. 1 <0. 1 Thamnolia verrnicularis 0.2 {ll 0. 1 {ll Cratoneuron sp. <0. 1 5 .7 Cyanobacteria 2.3 13.6 Dicranum angusturn 0. 1 3.3
Total 1 22.5 1 1 4.8 75.2 60.6
Additional species, occurring only in one cluster with a low frequency.
1 : Saxifraga foliolosa (< 0. 1 ), Ceratodon purpureus (<0. 1 ), Dicranurn rnajus ( 1 .4), Kiaeria glacialis (<0. 1 ), Oncophorus virens (<0. 1 ), Oncophorus wahlenbergii (<0. 1 ),
Polytrichastrurn sexangulare ( <0. 1 ), Polytrichum strictum ( <0. 1 ), Racomitrium ericoides (0. 1 ), Racornitrium panschii (0.2), Racornitriurn sudeticum ( <0. 1 ), Blepharostoma
trichophyllurn (0.2), Gyrnnornitrion concinnaturn (<0. 1 ), Odontoschisma macounii (0.7), Ptilidiurn ciliare (0.8), Tritomaria scitula (<0. 1 ), Alectoria nigricans (<0. 1 ),
A rctocetraria nigricascens ( <0. 1 ), Cladonia amaurocraea ( <0. 1 ), Cladonia macrophylla ( <0. 1 ), Cladonia rnacroceras ( <0. 1 ), Peltigera malacea ( <0. 1 ), Solorina octospora
(<0. 1 )
2 : Draba corymbosa ( <0. 1 ) , Equisetum variegatum (0.2), Phippsia algida ( <0. 1 ) , Trisetum spicatum ( <0. 1 ) , Encalypta rhaptocarpa ( <0. 1 ), Timmia norvegica ( <0. 1 ),
Cephaloziella arctica ( <0. 1 ), Tetralophozia setiformis ( 1 . 1 ), Cladonia coccifera ( <0. 1 ), Peltigera apthosa ( <0. 1 )
3 : Polemonium boreale ( <0. 1 ) , Saxifraga hieracifolia ( <0. 1 ) , Abietinella abietina ( <0. 1 ), Fulgensia bracteata ( <0. 1 ) , Peltigera canina ( <0. 1 ) , Solorina bispora ( <0. 1 )
4 : Festuca brachyphylla (<0. 1 ), Festuca hyperborea (<0. 1 ), Min.uartia bijlora (<0. 1 ), Potentilla pulchella (<0. 1 ), Campylium stellatum (0. 1 ), Encalypta alpina (<0. 1 ),
Encalypta streptocarpa (<0. 1 ) , Stereocaulon glareosum (0. 1 )
Acta Phytogeogr. Suec. 82
58 R. Virtanen & S . Eurola
Appendix 1 0. Mean percentage cover of plants in the moss tundra communities. 1 - Sanionia-Saxifraga hyperborea community, 2 -Aulacomnium turgidum-Alopecurus borealis community, 3 - Aulacomnium turgidum-Hylocomium community, 4 - Racomitrium canescens-Oxyria community. For frequencies, see Appendix 1 .
2 4 2 3 4
Alopecurus borealis 0.3 10.3 8.8 2.3 Polytrichum pi life rum lU <0. 1 Bistorta vivipara <0. 1 1 .4 1 .3 2.5 Polytrichum strictum 0.5 0.2 0.2 Cardamine bellidifolia <0. 1 <0. 1 lU Racomitrium canescens <0. 1 1 . 1 17.3
Cassiope tetragona 20.2 Racomitrium ericoides <0. 1 <0. 1 Cerastium arcticum <0. 1 <0. 1 lU Racomitrium lanuginosum 0.3 <0. 1 Cerastium regelii lU Sanionia uncinata 35.2 6.3 16.6 10.1
Draba micropetala <0. 1 <0. 1 Sarmentypnum sarmentosum 6.8 8.3 4.0 Equisetum arvense <0. 1 1 .3 <0. 1 Scorpidium revolvens 6.3 <0. 1 Equisetum variegatum <0. 1 <0. 1 Timmia austriaca <0. 1 <0. 1 .L.Q Luzula arctica 0.4 0.3 0.7 lU Tomentypnum nitens 4.1 0.7 8.0
Luzula arcuata ssp. confusa 2.4 3.8 7.4 10.6
Oxyria digyna M <0. 1 0.7 Anastrophyllum minutum <0. 1 0.5 lU Pedicularis hirsuta lU 0.3 <0. 1 Anthelia juratzkana lU Poa alpigena 0.5 il 1 .7 Blepharostoma trichophyllum 0.9 3 . 1 5.2
Poa alpina <0. 1 <0. 1 Cephaloziella arctica <0. 1 2.5 .u <0. 1 Poa arctica <0. 1 1 .3 0.3 0.3 Cephalozia sp. 0.8 0.7 Potentilla hyparctica <0. 1 <0. 1 Gymnomitrion concinnatum J..Q,_8_ Ranunculus pygmaeus 0.2 Gymnomitrion cora/lioides 1 .3 0.2 0.6 0.4 Ranunculus sulphureus <0. 1 0.3 lU <0. 1 Lophozia wenzelii 0.3 <0. 1 <0. 1 Sagina nivalis <0. 1 <0. 1 Marsupella boeckii 0.2 6.3 <0. 1 Salix polaris 2.3 15.0 25.5 13.2 Odontoschisma macounii lU <0. 1 0.5 <0. 1 Saxifraga cernua <0. 1 lU <0. 1 <0. 1 Ptilidium ciliare <0. 1 0.3 <0. 1 .L2 Saxifraga cespitosa <0. 1 lU <0. 1 Tritomaria quinquedentata 1 . 1 0.7 <0. 1 Saxifraga foliolosa lU 0.2 0. 1 Tritomaria scitula 0.8 lU Saxifraga hieracifolia lU Saxifraga hirculus <0. 1 <0. 1 Candelariella sp. <0. 1 <0. 1 Saxifraga hyperborea 0.2 <0. 1 Cetraria islandica <0. 1 lU Saxifraga nivalis <0. 1 lU <0. 1 Cetraria islandica ssp. crispiformis <0. 1 <0. 1 Saxifraga oppositifolia 1 .0 <0. 1 <0. 1 Cetraria nigricans <0. 1 <0. 1 Stellaria longipes coli . 0.2 0.3 0.3 Cetrariella delisei <0. 1 <0. 1 <0. 1 <0. 1
Cladonia amaurocraea <0. 1 lU Aulacomnium turgidum 0.5 1 7.8 2 1 .8 13.7 Cladonia chlorophaea 0.2 <0. 1 0.2 <0. 1 Bartramia ithyphylla <0. 1 lU lU Cladonia coccifera 0. 1 lU <0. 1 Bryum cryophilum 0. 1 Cladonia gracilis 0.2 <0. 1 <0. 1 0.4
Bryum spp. <0. 1 3.8 Cladonia macrophylla <0. 1 <0. 1 lU Calliergon stramineum <0. 1 .u Cladonia pocillum lU <0. 1 0.2 Conostomum tetragonum 0.2 1 .4 0.2 <0. 1 Cladonia pyxidata <0. 1 <0. 1 Cratoneuron sp. <0. 1 <0. 1 0. 1 Nephroma expallidum 0.2 0.7 Dicranum angustum lL.8. 7.5 .8.3. 2d Ochrolechia frig ida 2.8 0.3 1 .5 2.0 Dicranum elongatum <0. 1 2.2 0.8 Peltigera apthosa <0. 1 Q2 <0. 1 Dicranum fuscescens 0.8 M 2.4 Peltigera canina 0.2 Q,2 0.3 Dicranum majus <0. 1 1 2.6 <0. 1 Q,2 Peltigera leucophlebia 0.3 0.7 Qj_ Dicranum spadiceurn <0. 1 0.4 Q,2 Peltigera rufescens <0. 1 0.6 <0. 1 lU Distichium capillaceurn <0. 1 <0. 1 Psoroma hypnorum <0. 1 0.2 0.4 Q,2 Ditrichum flexicaule 3 . 1 <0. 1 Rinodina turfacea lU Hylocomium splendens var. alaskanum lU 7.2 3.7 Solorina crocea <0. 1 lU <0. 1 Kiaeria glacialis 0.7 0. 1 Stereocaulon alpinum 0.3 0.6 2 . 1 Meesia uliginosa 0.5 <0. 1 Stereocaulon glareosum 0.5 <0. 1 Oncophorus virens lU <0. 1 <0. 1 Stereocaulon rivulorum 0.8 <0. 1 3.7 Oncophorus wahlenbergii 0.2 <0. 1 0.4 Stereocaulon saxatile <0. 1 0.4 Pohlia nutans <0. 1 <0. 1 Stereocaulon vesuvianum 0.5 <0. 1 Pohlia spp. 0.2 <0. 1 Stereocaulon sp. <0. 1 1 .4 1 .0 Polytrichastrum alpinum 1 0. 1 D_ M Thamnolia vermicularis lU lU <0. 1 Polytrichurn juniperinum 0.6 0.3 0.3
Total 1 0 1 .3 1 30. 1 1 34.6 144.3
Additional species, occurring only in one or two clusters with a low frequency. I : Campylium stellatum ( <0. 1 ) , Dicranoweisia crispula ( <0. 1 ), Loeskypnum badium ( <0. 1 ), Polytrichastrum sexangulare ( <0. 1 ), Lophozia opacifolia ( <0. 1 ), Scapania tundrae ( <0. 1 ), Cladonia bellidijlora ( <0. 1 ), Cladonia cervicornis ( <0. 1 ), Cladonia macroceras ( <0. 1 ), Cladina arbuscula ssp. mitis ( <0. 1 ), Physconia muscigena ( <0. 1 )
2 : Draba corymbosa ( <0. 1 ), Equisetum scirpoides (0.3), Aulacomnium palustre ( <0. 1 ), Cirriphyllum cirrosum ( <0. 1 ) , Cynodontium strumiferum ( <0. 1 ) , Hypnum vaucheri (<0. 1 ), Meesia triquetra (<0. 1 ), Orthothecium chryseum (<0. 1 ), Philonotis fontana (<0. 1 ), Platydictya jungermannioides (<0. 1 ), Tortula ruralis (<0. 1 ), Tetralophozia setiformis (2.5), Collema tenax (2.5)
3: Drabajladnizensis ( <0. 1 ), ]uncus biglumis (0. 1 ) , Koenigia islandica (0. 1 ), Papaver dahlianum ( <0. 1 ), Saxifraga jlagellaris ( <0. 1 ), Hypnum recurvatum ( <0. 1 ), Hypnum revolutum (0.6), /sopterygiopsis pulchella (<0. 1 ), Kiaeria starkei (<0. 1 ), Polytrichum hyperboreum (0. 1 ), Caloplaca sp. (<0. 1 ), Cetraria aculeata (<0. 1 ), Collema limosum ( <0. 1 ), Sphaerophorus globosus ( <0. 1 ), Stereocaulon tomentosum ( <0. 1 ) 4 : Draba alpina ( <0. 1 ), Draba norvegica ( <0. 1 ), Draba oxycarpa ( <0. 1 ), Draba subcapitata ( <0. 1 ), Dryas octopetala (0.4), Huperzia se/ago ( <0. 1 ), Pedicularis lanata ssp. dasyantha (<0. 1 ), Silenefurcata (<0. 1 ), Pogonatum dentatum (2. 1 ), Scapania irriqua (<0. 1 ), Alectoria nigricans (<0. 1 ), Buellia papillata (<0. 1 ), Peltigera malacea (<0. 1 )
Acta Phytogeogr. Suec. 82
Middle oroarctic vegetation in Finland and middle-northern arctic vegetation on Svalbard 59
Appendix 1 1 . Mean percentage cover of plants in the Sanionia snow bed communities. 1 - Sanionia snowbed, 2 - Sanionia-Poa alpigena snowbed. For frequencies, see Appendix 1 .
2
Alopecurus borealis 0.5 0.4 Dicranum majus <0. 1
Bistorta vivipara 1 .2 Dicranum spadiceum <0. 1
Cardamine bellidifolia <0. 1 Ditrichum jlexicaule <0. 1
Cardamine pratensis ssp. polemonioides <0. 1 Hylocomium splendens var. alask.anum 0.6 3 .8
Cerastium arcticum 1 . 1 0.6 Hypnum bambergeri <0. 1
Cerastium regelii 0.2 0.2 Oncophorus wahlenbergii 0.3
Cochlearia groenlandica 0.2 <0. 1 Philonotis tomentella 1 .3
Deschampsia alpina <0. 1 Pohlia cruda <0. 1
Draba alpina <0. 1 Pohlia spp. 0.8 <0. 1
Draba corymbosa <0. 1 Polytrichastrum alpinum 0.2 4.5
Draba Lactea <0. 1 Polytrichastrum sexangulare 0.7
Draba subcapitata <0. 1 Polytrichum juniperinum 0.4
Dupontia fisheri u Polytrichum strictum <0. 1
Equisetum arvense bQ Racomitrium canescens <0. 1 <0. 1
Equisetum variegatum 0.2 Racomitrium Lanuginosum <0. 1
Luzula arctica <0. 1 Sanionia uncinata 58.1 45.4
Luzula arcuata ssp. confusa u 2.0 Sarmentypnum sarmentosum <0. 1
Minuartia bijlora <0. 1 Timmia austriaca 0.6 <0. 1
Oxyria digyna 0.3 Q,2 Tomentypnum nitens <0. 1 4.2
Pedicularis hirsuta <0. 1 Tortula ruralis 0.3
Phippsia algida <0. 1 <0. 1
Poa abbreviata <0. 1 Cephaloziella arctica 2.5 <0. 1
Poa alpigena <0. 1 1 0. 1 Gymnomitrion corallioides 0.8
Poa alpina 0.2 <0. 1 Hepaticae spp. 5 .0
Poa arctica 0.6 Marsupella sp. 0.3
Ranunculus pygmaeus <0. 1 0.3 Ptilidium ciliare 0.8
Ranunculus sulphureus 0.3 0.3 Tritomaria quinquedentata <0. 1
Sagina nivalis <0. 1
Salix polaris 2.9 2,.2 Cetraria islandica 1 .9
Saxifraga cemua 0.4 Q2 Cctrariclla dclisei LQ <0. 1
Saxifraga cespitosa !U !U Cladina arbuscula ssp. mitis <0. 1
Saxifraga foliolosa <0. 1 <0. 1 Cladonia amaurocraea <0. 1
Saxifraga hieracifolia <0. 1 Cladonia chlorophaea <0. 1 0. 1
Saxifraga hirculus <0. 1 Cladonia gracilis 0.2 <0. 1
Saxifraga hyperborea 0. 1 !U Cladonia pocillum <0. 1 <0. 1
Saxifraga nivalis <0. 1 !U Cladonia sp. <0. 1
Saxifraga oppositifolia .L1 0.3 Flavocetraria cucullata <0. 1
Saxifraga rivularis 0.3 <0. 1 Flavocetraria nivalis <0. 1
Silene acaulis <0. 1 Lecidea sp. <0. 1
Stellaria longipes coi l . 0. 1 0.2 Ochrolechia frigida <0. 1 0.3
Trisetum spicatum <0. 1 Peltigera apthosa <0. 1
Peltigera canina 0.4
Aulacomnium pa/ustre 5 .7 0. 1 Peltigera leucophlebia 0. 1
Aulacomnium turgidum 3.0 2.8 Peltigera rufescens 0.7 <0. 1
Bartramia ithyphylla 0.2 Psoroma hypnorum <0. 1
Brachythecium turgidum 0.2 Rinodina turfacea <0. 1
Bryum cryophilum <0. 1 0.4 Stereocaulon alpinum u Bryum sp. <0. 1 0.5 Stereocaulon glareosum <0. 1
Calliergon stramineum 6.3 0.5 Stereocaulon rivulorum <0. 1 0.3
Campylium stellatum <0. 1 Stereocaulon tomentosum 1 .3
Ceratodon purpureus 2.5 Stereocaulon sp. <0. 1 0.7
Cratoneuron sp. <0. 1 <0. 1 Thamnolia vermicularis <0. 1 <0. 1
Dicranum angustum 5.0
Dicranum fuscescens <0. 1 Total 1 03. 1 1 03.8
Acta Phytogeogr. Suec. 82
60 R. Virtanen & S. Eurola
Appendix 1 2. Mean percentage cover of plants in wet snowbed communities. The Scorpidium revolvens-Tomentypnum community. For frequencies, see Appendix 1 .
Alopecurus borealis 0.8 Campylium stellatum 1 .8
Bistorta vivipara 8.0 Cinclidium arcticum 0.2
Calamagrostis stricta 0.8 Distichium capillaceum � Carex bigelowii 0.5 Ditrichum flexicaule <0. 1
Cerastium arcticum <0. 1 Fissidens osmundoides <0. 1
Cerastium regelii 0.2 Hygrohypnum luridum 0.8
Deschampsia alpina 0.2 Hylocomium alaskanum <0. 1
Draba alpina <0. 1 Meesia uliginosa <0. 1
Dupontia fisheri 0.2 Orthothecium chryseum lU Equisetum arvense 3.0 Sanionia uncinata 8.5
Equisetum variegatum 7.1 Sarmentypnum sarmentosum 5.0
Oxyria digyna 0.7 Scorpidium revolvens 28.4
Pedicularis hirsuta <0. 1 Tayloria Ungulata <0. 1
Phippsia algida <0. 1 Timmia austriaca <0. 1
Poa alpigena kQ Tomentypnum nitens 17.3
Poa alpina !U Tortella fragilis 0.5
Poa arctica 0.3 Tortula ruralis <0. 1
Ranunculus nivalis gu Ranunculus sulphureus 0.3 An thelia juratzkana 0.5
Salix polaris 2.4 Lophozia sudetica <0. 1
Saxifraga cemua Q2 Saxifraga foliolosa <0. 1 Cetrariella delisei <0. 1
Saxifraga hieracifolia <0. 1 Cladonia pocillum <0. 1
Saxifraga hirculus Q,2 Cladonia sp. <0. 1
Saxifraga hyperborea <0. 1 Crustaceous black 1 0. 1
Saxifraga nivalis <0. 1 Crustaceous bchens M Saxifraga oppositifolia .LQ Flavocetraria nivalis <0. 1
Silene acaulis 0.3 Peltigera apthosa <0. 1
Taraxacum sp. <0. 1 Peltigera leucophlebia <0. 1
Peltigera rufescens <0. 1
Aulacomnium turgidum Q2 Solorina bispora <0. 1
Brachythecium turgidum <0. 1 Stereocaulon alpinum <0. 1
Bryum pallescens 1 .7 Stereocaulon sp. � Bryum sp. 7.5
Calliergon orbiculari·cordatum <0. 1 Total 1 1 8.7
Acta Phytogeogr. Suec. 82
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63. S. Brakenhielm. 1 977. Vegetation dynamics of afforested farmland in a district of south-eastern Sweden. ISBN 9 1 -72 1 0-063-X (ISBN 9 1 -72 1 0-463-5). Price: 240 SEK.
64. M. Y Ammar. 1 978. Vegetation and local environment on shore ridges at Vickleby, bland, Sweden. An analysis. ISBN 9 1 -72 1 0-064-8 (ISBN 9 1 -72 1 0-464-3) . Price: 240 SEK.
65. L. Kullman. 1 979. Change and stability in the altitude of the birch tree-limit in the southern Swedish Scandes 1 9 1 5-1 975. ISBN 9 1 -72 1 0-065-6 (ISBN 9 1 -72 1 0-465- 1 ) . Price: 240 SEK.
66. E. Waldemarson Jensen. 1 979. Successions in relationship to lagoon development in the Laitaure delta, North Sweden. ISBN 9 1 -72 1 0-066-4 (ISBN 9 1 -72 1 0-466-X). Price:
240 SEK.
Svenska Viixtgeografiska Siillskapet 63
67. S. Tuhkanen. 1 980. Climatic parameters and indices in plant geography. ISBN 9 1 -72 1 0-067-2 (ISBN 9 1 -72 1 0-467-8). Price: 240 SEK.
68. Studies in plant ecology dedicated to Hugo Sjors. E. Sjogren (ed.) 1 980. ISBN 9 1 -72 1 0-068-0 (ISBN 9 1 -72 1 0-468-6). Price: 290 SEK.
69. C. Nilsson . 1 98 1 . Dynamics of the shore vegetation of a North Swedish hydro-electric reservoir during a 5-year period. ISBN 9 1 -72 1 0-069-9 (ISBN 9 1 -72 1 0-469-4 ). Price: 240 SEK.
70. K. Warenberg. 1 982. Reindeer forage plants in the early grazing season. Growth and nutritional content in relation to climatic conditions. ISBN 9 1 -72 1 0-070-2 (ISBN 9 1 -72 1 0-470-8). Price: 240 SEK.
7 1 . C. Johansson. 1 982. Attached algal vegetation in running waters of Jamtland, Sweden. ISBN 9 1 72 1 0-07 1 -0 (ISBN 9 1 -72 1 0-47 1 -6). Price: 240 SEK.
72. E. Rosen. 1 982. Vegetation development and sheep grazing in limestone grasslands of South bland, Sweden. ISBN 9 1 -72 1 0-072-9 (ISBN 9 1 -72 1 0-472-4). Price: 290 SEK.
73. Zhang Liquan. 1 983. Vegetation ecology and population biology of Fritillaria meleagris L. at the Kungsangen Nature Reserve, eastern Sweden. ISBN 9 1 -72 1 0-073-7 (ISBN 9 1 -72 1 0-473-2). Price: 240 SEK.
74. I. Backeus. 1 985. Aboveground production and growth dynamics of vascular bog plants in central Sweden. ISBN 9 1 -72 1 0-074-5 (ISBN 9 1 -72 1 0-474-0). Price: 240 SEK.
75. E. Gunnlaugsd6ttir. 1 985. Composition and dynamical status of heathland communities in Iceland in relation to recovery measures. ISBN 9 1 -72 1 0-075-3 (ISBN 9 1 -72 1 0-475-9). Price: 240 SEK.
76. Plant cover on the limestone Alvar on bland. EcologySociology-Taxonomy. E. Sjogren (ed.) 1 988. ISBN 9 1 -72 1 0-076- 1 (ISBN 9 1 -72 1 0-476-7). Price: 320 SEK.
77. A. H. Bjamason. 1 99 1 . Vegetation on lava fields in the Hekla area, Iceland. ISBN 9 1 -72 1 0-077-X (ISBN 9 1 -72 1 0-477-6). Price: 290 SEK.
78. I. Wallentinus & P. Snoeijs (eds.). 1 992. Algological studies of Nordic coastal waters - A festschrift to Prof. Mats Wrem on his 80th birthday-. ISBN 9 1 -72 1 0-078-8 (ISBN 9 1 -72 1 0-478-3 ) . Price: 290 SEK.
79. Tamrat Bekele. 1 993. Vegetation ecology ofremnant Afromontane forests on the Central Plateau of Shewa, Ethiopia. ISBN 9 1 -72 1 0-079-6 (ISBN 9 1 -72 1 0-479- 1 ) . Price: 290 SEK.
80. M. Diekmann. 1 994. Deciduous forest vegetation in Boreonemoral Scandinavia. ISBN 9 1 -72 1 0-080-X (ISBN 9 1 -72 1 0-480-5). Price: 290 SEK.
8 1 . Plant root systems and natural vegetation. 1 996. H . Persson & I .O. Baitulin (eds .) ISBN 9 1 -72 1 0-08 1 -8 (ISBN 9 1 -72 1 0-08 1 -3) . Price: 290 SEK.
82. Middle oroarctic vegetation in Finland and middle-northem arctic vegetation on Svalbard 1 996. R. Virtanen & S. Eurola (eds.) ISBN 9 1 -72 1 0-082-6. (9 1 -72 1 0-482-5). Price: 290 SEK.
A limited number of cloth-bound copies of Acta 44, 45, 46, 48, 49, 5 1 , 52, 53, 56, 57, 6 1 , 63, 66, 67, 68, 69, 70, 7 1 , 72, 73, 74, 75, 76, 77, 78, 79, 80 and 81 is available at an additional cost of 75 SEK per volume. (Use ISBN n°S. within brackets to order.)
Acta Phytogeogr. Suec. 82
64 Svenska Viixtgeografiska Siillskapet
STUDIES IN PLANT ECOLOGY (VOL. 1 - 1 9)
1 . S. Brakenhielm & T Ingelog. 1 972. Vegetationen i Kungshamn-Morga naturreservat med forslag till skotselplan. (Summary: Vegetation and proposed management in the Kungshamn-Morga Nature Reserve south of Uppsala.) ISBN 9 1 -72 1 0-80 1 -0. Price: 1 1 2 SEK.
2. T. Ingelog & M. Risling. 1 973. Kronparken vid Uppsala, historik och bestandsanalys av en 300-ang tallskog. (Summary : Kronparken, history and analysis of a 300-year old pinewood near Uppsala, Sweden.) ISBN 9 1 -72 1 0-802-9. Price: 1 1 2 SEK.
3. H. Sjiirs et al. 1 973. Skyddsvarda myrar i Kopparbergs Hin. [Summary: Mires considered for protection in Kopparberg County (Prov. Dalama, Central Sweden.)] ISBN 9 1 -72 1 0-803-7. Price: 1 1 2 SEK.
4. L. Karlsson. 1 973. Autecology of cliff and scree plants in Sarek National Park, northern Sweden 1 973 . ISBN 9 1 -72 1 0-804-5. Price: 1 60 SEK.
5. B. Klasvik. 1 974. Computerized analysis of stream algae. ISBN 9 1 -72 1 0-805-3. Price: 1 1 2 SEK.
6. Y. Dahlstrom-Ekbohm. 1 975 . Svensk miljovards- och omgivningshygienlitteratur 1 952- 1 972. Bibliografi och analys. ISBN 9 1 -72 1 0-806- 1 . Price: 1 1 2 SEK.
7. L. Rodenborg. 1 976. Bodennutzung, Pflanzenwelt und ihre Verlinderungen in einem alten Weidegebiet auf Mittel-Oland, Schweden. ISBN 9 1 -72 1 0-807-X. Price: 1 1 2 SEK.
8. H. Sjors & Ch. Nilsson. 1 976. Vattenutbyggnadens effekter pa levande natur. En faktaredovisning overvagande fran Umealven. (Summary: B ioeffects of hydroelectric development. A case study based mainly on observations along the Ume River, northern Sweden.) ISBN 9 1 -72 1 0-808-8. Price: 1 60 SEK.
9. J. Lundqvist & G. Wistrand. 1 976. Strandflora inom ovre och mellersta Skelleftealvens vattensystem. Med en sammanfattning betraffande botaniska skyddsvarden. (Summary: Riverside vascular flora in the upper and middle catchment area of the River Skelleftealven, northern Sweden. ) ISBN 9 1 -72 1 0-809-6. Price: 1 1 2 SEK.
1 0. A. Mii.ller-Haeckel. 1 976. Migrationsperiodik einzelliger Algen in Fliessgewassern. ISBN 9 1 -72 1 0-8 1 0-X. Price: 1 1 2 SEK.
1 1 . A. Sjodin . 1 980. Index to distribution maps of bryophytes 1 887- 1 975. 1 . Musci. (hard-bound) . ISBN 9 1 -72 1 0-8 1 1 -8 . Price: 1 60 SEK.
1 2. A. S}Odin. 1 980. Index to distribution maps of bryophytes 1 887- 1 975. II. Hepaticae. (hard-bound) . ISBN 9 1 -72 1 0-8 1 2-6. Price: 1 1 2 SEK.
1 3 . 0. Eriksson, T Palo & L. Soderstrom. 1 98 1 . Renbetning vintertid. Undersokningar rorande svensk tarnrens naringsekologi under snoperioden. ISBN 9 1 -72 1 0-8 1 3 -4. Price: 1 1 2 SEK.
1 4. G. Wistrand. 1 98 1 . Bidrag till Pite lappmarks vaxtgeografi. ISBN 9 1 -72 1 0-8 14-2. Price: 1 1 2 SEK.
1 5 . T. Karlsson. 1 982. Euphrasia rostkoviana i Sverige. ISBN 9 1 -72 1 0-8 1 5-0. Price: 1 60 SEK.
1 6. Theory and Models in Vegetation Science: Abstracts. ISBN 9 1 -72 1 0-8 1 6-9. 1 985. Price: 1 60 SEK.
1 7 . /. Backeus. 1 988. Mires in the Thaba-Putsoa Range of the Maloti, Lesotho. ISBN 9 1 -72 1 0-8 1 7-7. Price: 1 60 SEK.
1 8 . Forests of the world - diversity and dynamics (Abstracts) 1 989. (Ed. E. Sjogren) ISBN 9 1 -72 1 0-8 1 8-5 . Price: 290 SEK.
1 9. E. Sjogren. 1 994. Changes in the epilithic and epiphytic moss cover in two deciduous forest areas on the island of bland (Sweden) . - A comparison between 1 958- 1 962 and 1988- 1 990. ISBN 9 1 -72 1 0-8 1 9-3. Price: 200 SEK.
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