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LINDBERGIA 29:3 (2004) 129

LINDBERGIA 29: 129–135. Lund 2004

Populations of Sphagnum angermanicum in Sweden:distribution, habitat requirements and threats

Urban Gunnarsson

Gunnarsson, U. 2004. Populations of Sphagnum angermanicum in Sweden:distribution, habitat requirements and threats. – Lindbergia 29: 129–135.

This study investigates the conservation status of the redlisted bryophyte Sphag-num angermanicum in Sweden. The majority of the known Swedish localities

were visited and population sizes estimated. pH, height above the groundwatertable, horizontal distance to mineral ground, associated species and disturbancedegree were investigated for each population. Sphagnum angermanicum wasfound in 19 of the 20 populations visited. Most populations were small, witheight occupying less than 5 m2. The populations occurred on mires with meanpH of 4.9, mean height above the groundwater table of 18 cm and mean hori-zontal distance to the closest mineral ground of 25 m. There was a quadraticrelationship between pH and population sizes, where the largest populationswere found at intermediate pH (about pH 5). The low number and small sizesof the Swedish populations make them sensitive to environmental changes,stochastic events and deterministic habitat loss. There is thus a clear need forspecial conservation attention. The species seems to benefit from some kind of fine-scale disturbance like trampling of large mammals and wheel tracks of small cross-country vehicles. A map of the known Scandinavian distribution is

presented and discussed in relation to the species’ potential dispersal capacity.U. Gunnarsson, Dept of Biology, Norwegian Univ. of Science and Technology, NO-7491, Trondheim, Norway ([email protected]).

Accepted 9 September 2004

© LINDBERGIA 2004

In Sweden there is a total of 241 redlisted bryophytespecies (Hallingbäck et al. 1998), including twoSphagna, S. angermanicum Melin and S. strictum Sull.Both occur mainly in the western parts of the country.The present day distributions of these two species arewell known while current threats and habitat require-

ments are not.Sphagnum angermanicum was described by Melin(1919) on material from the Swedish mire Vålands-myren (in the province of Ångermanland). Thereafterit took more than 40 years until the species was redis-covered at the type locality (in 1960) and found inherbarium collections from Nova Scotia (Maass 1965,1967). Furthermore, Maass (1965, 1966) discoveredseveral new localities in North America and reportednew localities both in Sweden and Norway. Since the

publications by Maass (1965, 1967) the status of S.angermanicum as a distinct species has been settledand several new Scandinavian localities have beenreported (Sjörs 1966, Skogen 1970, Eriksson 1972,1979, 1996, Flatberg and Moen 1972, Økland 1989a,Abenius 1993, Liljegren 1994).

Sphagnum angermanicum

has an amphi-Atlanticdistribution. It occurs in eastern North America fromNew Jersey to southern Labrador (Maass 1967,Phillips and Miller 2001). Its known European distri-bution is confined to Scandinavia (Flatberg and Moen1972, Hallingbäck et al. 1998) and a single occurrenceis reported from Iceland (Jóhannsson 1992). Reportsfrom other European countries (Frey et al. 1995) seemto be based on misidentifications. The species isdioecious and only a single Scandinavian specimen,from a locality in southwest Norway (specimen inTRH), has been seen with sporophytes. In Newfound-land it has more often been reported with sporophytes



130 LINDBERGIA 29:3 (2004)

Sweden

A

B

Norway

(Maass 1966, 1967). In Norway S. angermanicumtypically grows in sloping fens (Flatberg and Moen1972) with a pH interval of 4.0–5.3 and in sites withtypical intermediate fen vegetation.

The aims of this study are to investigate, 1) the sta-tus of S. angermanicum populations in Sweden, 2) itshabitat requirements, 3) the relation between popula-tion sizes and the environmental conditions, and 4) tocompile a new distribution map of the known S. an-germanicum localities in Scandinavia. All four of theseissues are discussed in relation to conservation status.

Material and methods

In the summer of 2001 I visited 20 known localitiesof Sphagnum angermanicum in Sweden. Localitieswere sought in the literature (Melin 1919, Maass 1965,

Sjörs 1966, Eriksson 1972, 1979, 1996, Abenius 1993,Liljegren 1994), in herbaria (BG, O, TRH, UPS andS), in the register of localities for threatened speciesin Sweden (Swedish Threatened Species Unit, Swed-ish Univ. of Agric. Sci., Uppsala) and by personalcommunication with Pell Algot Eriksson (Malungs-fors, Sweden) and Hugo Sjörs (Dept of Plant Ecol-ogy, Uppsala Univ.). All known localities were vis-ited except some situated in western Dalarna.

At each locality where S. angermanicum was presentI estimated the population size and recorded pH (witha glass electrode directly in the mire water), height

above the groundwater table (GWT, with a gradedstraw) and horizontal distance to the closest surround-ing mineral ground. The groundwater table in miresfluctuates strongly (Malmer 1962, Økland 1989b), sothat measurements made at different time-points arenot strictly comparable. However, the measure usedhere gives a relative estimate of the position along thehollow-hummock gradient. Sporophyte presence andthe vascular plant and bryophyte species growing indirect association with S. angermanicum (i.e. grow-ing among plants of S. angermanicum) were recorded.The pH and GWT were measured at several points

(usually 2–5) in each population and the mean valuewas calculated. In order to get a comparable measureof disturbance regime, I ranked disturbance degree onan ordinal scale according to the frequency and spa-tial extension of disturbance at each locality as: 0) nodisturbance (no obvious disturbances the last 10 years),1) fine-scale (< 1 m2), low frequency disturbance (oncewithin a 5 year period), 2), 3) and 4) intermediate scaleand/or frequency, 5) large (over large areas > 10 m2)or high-frequency disturbances (more than once eachyear, e.g. intense cattle trampling or regular flooding).The mean pH-values in the localities with S. anger-manicum were compared with a pH histogram from

889 measurements in central Swedish mires extractedfrom the literature (Sjörs and Gunnarsson 2002). Thelinear and non-linear (second order functions) betweenpopulation size and explanatory characters (pH, GWT,

distance to mineral soil, disturbance degree) weretested with multiple regression models. Since the dis-tribution of the response variable (population size) ismore likely to be Poisson rather than normal distrib-uted, log-link regressions were used, assuming Poissonerrors (S-PLUS 3.0). An analysis of deviance was usedto identify the best fit model and, as the scale param-eter is often under or over dispersed, the F-statisticswas used (Crawley 2002).

ResultsCurrent distribution in Scandinavia

Currently, herbarium collections of S. angermanicumare known from 127 localities in Scandinavia. Thelocalities form two main distribution areas (Fig. 1): asouth Norwegian and west-central Swedish area with60 localities and a central Norwegian area with 65localities. The southern area has a scattered distribu-tion of localities from the westernmost localities inNorway to the easternmost locality in Sweden (in theprovince of Gästrikland; Fig. 1). From this distribu-tion area there is a gap in the known distribution over

Fig. 1. The known Scandinavian distribution of Sphagnumangermanicum (see text for sources). The type locality (Vå-landsmyren) and the northernmost locality south of Tromsøare indicated A and B, respectively.



LINDBERGIA 29:3 (2004) 131

the southern Scandes and along most of the westerncoast north to the central Norwegian area. There aretwo known localities outside these main areas, one atthe type locality Vålandsmyren and one newly foundlocality just south of Tromsø (Troms, northern Nor-way, Fig. 1).

Swedish populations of Sphagnumangermanicum

Sphagnum angermanicum was found in 19 of the 20revisited localities (Table 1). The one locality whereS. angermanicum was not found was a small mire onthe border between the provinces Värmland andDalarna, (13°11′ E, 60°41′ N, 400 m a.s.l., describedin Eriksson 1972), severely affected by the digging of a channel in a small river. Otherwise the species wasrather easy to refind at the old localities. At the type

locality (Vålandsmyren, locality 20, Table 1), whereit previously has been reported as disappeared (Hal-lingbäck et al. 1998), I found it growing atypically onan open, flat Sphagnum papillosum fen, lacking manyof the species typically associated with it (Table 2).

The population sizes of the visited localities variedfrom 1 m2 to about 35 m2 with a median size of 5 m2

(Table 1). The largest of the populations was found ina large sloping fen in the centre of the Swedish distri-bution area in the parish of Malung, Dalarna, and the

Fig. 2. Distribution of pH measured in mire water in Swed-ish localities with Sphagnum angermanicum (filled bars)and pH in 889 mire localities with or without S. anger-manicum distributed over north and central Sweden (openbars, data from Sjörs and Gunnarsson 2002).

Table 1. Investigated localities with Sphagnum angermanicum in Sweden with approximate population size, mean val-ues of pH in mire water (range) and distance above the ground water table (GWT, range), distance to the surroundingmineral ground limit, and disturbance degree (se text for details).

DistancePop. to mineral Distur-

Population Long. Alt. size ground bancenumber, locality Lat. (E) (N) (m) (m2) pH GWT (cm) (m) degree

1 Ö Vallsjön 13°22′ 60°45′ 400 35 4.9 (4.4–5.0) 13 (5–21) 10 22 Lillbudkölen 13°23′ 60°45′ 420 2 4.1 (3.9–4.2) 7 (4–9) 10 13 Gråbron 13°24′ 60°43′ 375 6 5.7 (4.8–6.5) 17 (15–20) 7.5 34 Ö Älgsjön 13°29′ 60°37′ 425 5 4.7 (4.1–4.5) 37 (25–50) 75 55 Klambergsmyren 13°24′ 60°34′ 450 10 5.8 (5.2–6.4) 17 (15–20) 8 3

6 Digerbergshålet 13°24′ 60°34′ 550 2 4.4 (4.2–4.6) 15 (12–17) 30 37 Matsudden 13°23′ 60°32′ 400 20 5.0 (4.4–5.8) 19 (10–30) 20 48 Kattstjärtvadet 13°11′ 60°36′ 350 5 5.6 (5.3–5.8) 15 (8–25) 20 49 Kulltäppssätern 13°12′ 60°37′ 400 2 5.9 (5.6–6.4) 23 (15–30) 15 5

10 Stormyren 13°31′ 60°04′ 290 25 4.9 (4.0–6.4) 14 (9–21) 10 311 Flämtmyren 13°35′ 60°23′ 330 1.5 3.9 (3.7–4.1) 17 (9–30) 10 312 Karvalakmossen 14°30′ 59°59′ 250 1 – – 2 213 Bäckemyrbäcken 13°10′ 60°48′ 425 10 4.2 (4.0–4.5) 19 (13–26) 10 414 Valdroån 13°18′ 60°45′ 400 2 4.2 (4.0–4.5) 19 (15–23) 15 515 Emmådalen 14°43′ 61°19′ 450 30 5.1 (4.7–5.3) 17 (12–17) 10 216 Koppången 14°45′ 61°21′ 520 25 4.7 (4.6–4.8) 17 (12–25) 50 317 Flickran 14°49′ 61°20′ 500 10 5.3 (4.9–5.8) 16 (5–21) 10 419 Kolkilamp 16°20′ 60°50′ 280 2.5 5.4 (5.3–5.4) 18 (15–20) 10 420 Vålandsmyren 17°28′ 63°35′ 300 1.5 – 20 (18–22) 150 0



132 LINDBERGIA 29:3 (2004)

smallest at the southernmost locality Karvalakmossenin the province Västmanland (locality 12, Table 1). Ineight of the visited localities the populations covered

less than 5 m

2

.The localities fell into two habitat types. The mostcommon type was sloping intermediate fens, some-times with flarks (15 localities). Less common werepatches at the margins of streams (three localities) orlakes (one locality). At several locations S. angermani-cum was growing in sloping fens close to open water(< 20 m distance). Sphagnum angermanicum wasstrongly associated with Molinia caerulea and S. papillosum, which both occurred in more than 95%of the localities (Table 2). Other important associateswere Betula nana, Carex pauciflora, Potentilla erectaand Sphagnum angustifolium (found in 50–70% of the

localities). Other commonly associated species (foundin more than 25% of the localities) were: Calluna vul-garis, Carex echinata, C. lasiocarpa, C. rostrata,

Drosera rotundifolia, Eriophorum angustifolium, E.vaginatum, Menyanthes trifoliata, Sphagnum fuscum,S. magellanicum, S. pulchrum, S. rubellum, Succisa pratensis, Trichophorum caespitosum ssp. caespito-sum and Vaccinium oxycoccus.

The pH varied between 3.7 and 6.5 (mean 4.9±0.6SD, Fig. 2). The height above the ground water tableat the same localities varied between 4 and 50 cm(mean 18 cm ± 6 SD; Table 1). Sphagnum angermani-cum usually grew close to the mire margin, with shortdistances to the surrounding mineral ground, (mean25 m ± 35 SD). On Vålandsmyren (the type locality)S. angermanicum grew at an extremely long distance

Table 2. Species associated with Sphagnum angermanicum in the investigated Swedish localities. The list reports pres-ence/absence values for each species growing in mixture with S. angermanicum and frequency of each species over thelocalities. The nomenclature follows Karlsson (1997) for vascular plants and Söderström and Hedenäs (1998) forbryophytes.

Species Population Freq.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 19 20

Sphagnum papillosum 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 100% Molinia caerulea 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 95 %Carex pauciflora 1 1 1 0 1 1 1 0 0 1 0 1 1 1 1 1 0 1 0 68 %Potentilla erecta 0 0 1 0 1 1 0 1 0 1 0 1 1 0 1 1 1 1 0 58 % Betula nana 1 0 1 1 0 1 1 0 1 1 1 0 1 0 0 1 1 0 0 58 %Sphagnum angustifolium 1 0 1 1 1 1 0 0 0 1 0 1 1 1 1 1 0 0 0 58 % Eriophorum angustifolium 0 0 1 1 1 1 1 0 0 1 0 1 0 0 0 0 1 0 0 42 %Sphagnum rubellum 1 0 1 0 1 0 0 0 0 0 0 1 1 0 0 1 1 0 1 42 %Trichophorum cespitosum ssp.caespitosum 0 0 0 1 1 0 0 1 0 0 1 0 1 0 1 1 0 0 1 42 %Sphagnum fuscum 1 1 1 0 1 0 1 1 0 0 0 0 1 1 0 0 0 0 0 42 %Carex rostrata 0 0 0 1 0 1 1 0 0 1 0 1 1 0 0 1 1 0 0 42 %Calluna vulgaris 1 0 0 0 1 0 1 0 0 1 0 1 1 0 0 0 0 1 0 37 %

Menyanthes trifoliata 0 1 0 0 0 0 1 0 1 0 0 1 0 0 0 1 1 1 0 37 %Vaccinium oxyccocus 0 0 0 1 1 0 0 0 1 1 0 1 0 0 0 0 0 1 1 37 %Carex lasiocarpa 0 0 0 0 0 1 1 0 1 1 0 1 0 0 0 0 1 0 1 37 %Sphagnum pulchrum 0 0 0 0 0 1 1 1 0 1 0 0 0 0 1 1 0 0 0 32 % Drosera rotundifolia 0 0 0 0 1 1 0 0 0 1 0 1 0 0 0 1 0 1 0 32 %Sphagnum magellanicum 1 0 1 1 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 32 % Eriophorum vaginatum 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 1 32 %Carex echinata 0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 1 1 0 26 %Succisa pratensis 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 1 1 1 0 26 %Selaginella selaginoides 0 0 0 0 1 1 0 1 0 0 0 0 0 0 0 0 0 1 0 21 % Andromeda polifolia 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 16 %Carex magellanica 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 16 %Sphagnum russowii 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 1 0 0 16 %Viola palustris 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 1 0 16 %

The following species were found at one or two localities (population number within parenthesis): Betula pubescens(19), Carex chordorrhiza (9), C. dioica (3, 17), C. globularis (1), C. livida (15), Dactylorhiza maculata (3, 12), Equisetum fluviatile (6), E. palustre (19), Melampyrum pratense (6), Myrica gale (8), Phragmites australis (7), Polytrichum stric-tum (1), Rubus chamaemorus (1, 11), Sphagnum balticum (12), S. fallax (2, 7), S. flexuosum (13), S. lindbergii (10), S.majus (7), S. subfulvum (15), S. teres (2, 6), S. warnstorfii (8, 15), Trichophorum alpinum (1), Trientalis europaea (12,16). Small hepatics growing intermingled within the Sphagnum carpet were not recorded.



LINDBERGIA 29:3 (2004) 133

from the mineral ground (150 m), growing in the mid-dle of a large S. papillosum fen (Table 1). All locali-

ties except Vålandsmyren were affected by small dis-turbances, e.g. tracks (by wheel tracks of small cross-country vehicles, humans or moose) or by direct wa-ter action along streams and lakes. In the analysis of deviance, the disturbance degree and pH (the secondorder function) showed significant relations withpopulation size (Table 3). The maximum populationsize was found at intermediate pH (about 5.0, Fig. 3).The regression coefficient for disturbance degree wasweakly negative (Table 3).

No sporophytes were found at any of the visitedlocalities. However, at several of the locations I found

shoots with antheridia. Vegetative dispersal by meansof capitula fragmentation was often seen in the field.The breaking point was in the fragile transition re-gion between capitula and stem, ca 0.3 cm below theapex. The shoot continues to grow from innovationsof the uppermost branches.

DiscussionDistribution and dispersal

From the present knowledge of its distribution, it re-

mains a puzzle that Sphagnum angermanicum wasdescribed from a locality isolated by 250 km from its

closest neighbour. It is of course possible that this gapis caused by lack of knowledge, although the largeeffort put into the Swedish wetland inventory (per-formed by the Swedish Environmental ProtectionAgency) gives reason to believe that a large propor-tion of the Swedish localities is known.

The bicentric distribution of Sphagnum angermani-

cum in Scandinavia is partly explained by the south-ern Scandes. But its apparent absence from regionsbetween the two main areas in western Norway is lesseasily explained. Moen (1999) describes S. anger-manicum as having a slight oceanic affinity. Most of the Swedish and Norwegian localities are situated inthe boreal zone, but some of the south Norwegian lo-calities occur in the boreonemoral zone. The specieshas been reported from 20 m to about 500 m a.s.l.(Maass 1966), however, Skogen (1970) reports it from850 m in Norway. It is possible that the Scandinavianpopulations have established in postglacial time

through spore dispersal from North American over theAtlantic Ocean , as it is found sporulating on this con-tinent (Maass 1966, 1967). It can, however, not beruled out that S. angermanicum has survived the lastglaciation somewhere in western Europe.

One way to explain the current distribution patternof Sphagnum angermanicum is by a relict populationmodel. In the early Holocene S. angermanicum mighthave dispersed quite rapidly into Scandinavia over thevast areas of intermediate fens that probably occurredduring the Boreal and Atlantic periods (9000-5000years BP; Tolonen 1967, Rybíneck 1973). The Sphag-

num dominated peatlands started to establish some-what later in Europe during the Atlantic period (8000-5000 years BP, Tolonen 1967, Rybíneck 1973, Fosteret al. 1988) and successively changed the environment,including the intermediate fens, to become more acid(and less suitable for S. angermanicum). As the areaof poor fens and ombrotrophic bogs expanded, thenumber of S. angermanicum populations may havedecreased and the current populations may be relictpopulations of a formerly much larger distributionarea. The occurrence of disturbances at almost all siteswith S. angermanicum in Sweden might be a way in

which the vegetation remains in a suitable intermedi-ate fen state.

Fig. 3. The relation between Sphagnum angermanicumpopulation size and the mean locality pH (open circles).The regression line follows the fitted Poisson regressionmodel (Table 3, i.e. population size = e(-52.8 - 0.37 ´ disturbance degree+

22.8 ´ pH - 2.27 ´ pH²), with the disturbance degree set to 3.

Table 3. Summary of the best fit multiple regression model of Sphagnum angermanicum population size in relation toenvironmental variables (in this case pH and disturbance degree). Null deviance refers to the null model and df to themodel degrees of freedom.

Explanatory character df Deviance F-value P-value Coefficients

Null deviance 16 165.6Disturbance degree 1 29.1 8.93 0.010 -0.37pH 1 7.84 2.41 0.145 22.8pH2 1 86.2 26.45 <0.001 -2.27



134 LINDBERGIA 29:3 (2004)

In the past S. angermanicum may also have beenfertile in Scandinavia under better conditions forsexual reproduction and bryologists may simply haveoverlooked the sporophytes. Long distance dispersalmay also explain the present isolated localities inSweden, Norway and Iceland.

Fragmentation of capitula or other vegetative partsmay be important for short distance dispersal. Thefragments are likely to be transported by mammals(moose, sheep and humans are probably the main vec-tors) or by flowing surface water in wet periods. Ex-cept for the possible mammal transport of the frag-ments, trampling by itself or other small scale distur-bances might enhance the fragmentation process andthe establishment of the fragments on open disturbedground. The rather frequent occurrence of S. anger-manicum along streams and lakeshores, and its oc-currence in several localities in the same drainage area,indicate that water dispersal can be important.

Swedish populations of Sphagnum angermanicum

The Swedish Sphagnum angermanicum sites havesimilar vegetation composition as reported from Nor-way (Flatberg and Moen 1972), with S. papillosumand Molinia caerulea as more or less constantly asso-ciated species. The Swedish populations in additionhave Betula nana and Sphagnum angustifolium asconstant species and the occurrences of bryophytes

other than Sphagnum were less frequent in this study.It seems improbable that S. angermanicum is mutual-istically benefiting from the associated species; ratherthe species happen to have approximately the sameecological demands.

The pH values in sites with Sphagnum angermani-cum can be compared to the pH measures in 889 Swed-ish mire sites (Sjörs and Gunnarsson 2002). This pHdistribution is bimodal with fewest mires in the pHregion 4.9–5.4, coinciding with the region with mostS. angermanicum localities (Fig. 2). This pH intervalis typical for intermediate fens, which have been sug-

gested to be shortlived transitional communities be-tween rich and poor fen (Gorham et al. 1987, Vitt2000). This transition could take approximately 150years (Vitt and Kuhry 1992). Even if these communi-ties are short lived in some areas (Gunnarsson et al.2000) there are large areas covered with these poten-tially suitable habitats for S. angermanicum in Scan-dinavia.

A relationship was found between population sizeand pH, which indicates that pH is an important de-terminant for the population performance. However,it is not possible to draw the conclusion that pH around5.0 gives optimal growth conditions, but rather that

the realised niche of the species lies in this pH region.Most Sphagnum species do not grow at high pH (abovepH 6), except a few rich fen species (Clymo 1973).Towards the lower pH region, competition from otherpoor fen species may be responsible for the smallpopulation sizes in more acid sites.

Implications for conservation

Several of the Swedish populations of Sphagnum an-germanicum are small and widely separated. Thismakes them sensitive to environmental changes as wellas stochastic events. A change in water regime, e.g.flow or water quality, or in disturbance regime at par-ticular localities can cause local extinctions. The seem-ingly poor long-distance dispersal ability found inScandinavia at present reduces the probability that alocality will be recolonised. In a Scandinavian per-

spective the Swedish populations are at the margin of the species current distribution range. The species’status in Sweden is still unclear. There are some re-cently discovered localities (Abenius 1993, Liljegren1994) indicating either expansion or that the specieshas been overlooked. However, the number of newlocalities is low compared with the attention that S.angermanicum has received and no new localities werefound when I searched for it in potential suitable lo-calities.

The distribution and ecology of S. angermanicumindicate that the distribution is at present dispersal lim-

ited over longer distance. Firstly, sporophytes havebeen observed in Scandinavia only once. Secondly,the occurrences are locally clumped and the speciesis absent from large areas where potentially it couldgrow according to the satellite strategy (Söderströmand Jonsson 1992). It is puzzling that the species pro-duces sporophytes quite rarely in Scandinavia atpresent, since several populations consist of both maleand seemingly female plants (Flatberg 2002). Climaticfactors affect the temporal variation in spore produc-tion in Sphagnum species (Sundberg 2002). Nothingis, however, known about the temporal variation of

the spore production in S. angermanicum. Cronberg(1996) found little genetic variation in S. angermani-cum (20 shoots from three localities) using isozymesas genetic markers. This pattern might be a result of small population size, repeated bottlenecks or lack of sexual reproduction. There is, however, a need to lookat the genetic variation in more populations to be ableto identify at which level (within populations, oramong populations) S. angermanicum shows geneticvariation. In order to answer questions about thepostglacial dispersal history genetic analyses need toinclude populations from all parts of its distributionarea.



LINDBERGIA 29:3 (2004) 135

Acknowledgements – This study was financed by NorFaand Stiftelsen Extensus. I also thank Hugo Sjörs, Pell AlgotEriksson, Kjell Ivar Flatberg, Lars Söderström and NilsCronberg for constructive discussions and help with lo-calities and the herbaria in BG, O, S, TRH and UPS forhelp with herbarium specimen. Rune H. Økland, Kjell IvarFlatberg and Lars Söderström are also thanked for con-structive comments on the manuscript. Carolyn Baggerud

corrected the language.

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lindbergia 29-3 - 129-135===ekologi-sphagnum angermanicum===+

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