Ecology of Testaceans (Protozoa: Rhizopoda) in Mires in Southern Finland: I. Autecology

Arch. Protistenkd. 142 (1992): 119-138

AROt~

© by Gustav Fischer Verlag Jena

PROTISTEN

KUNDE

Ecology of Testaceans (Protozoa: Rhizopoda) in Mires in Southern Finland: I. Autecology KIMMO TOLONEN, BARRY

G.

WARNER

& HARRI

VASANDER

Department of Biology, University of Joensuu, Joensuu, Finland; Department of Geography, University of Waterloo, Waterloo, Ontario, Canada; Department of Peatland Forestry, University of HelSinki, HelSinki, Finland

Summary: The distribution of 38 testacean species (Protozoa: Rhizopoda) and a rotifer, Habrotrocha angusticollis (Rotifera: Bdelloidea) were analyzed by range and weighted average ordination techniques of seven chemical and four physical variables from 90 microsites in virgin mires in southern Finland. Both living and dead individuals were counted and the absolute numbers of individuals per unit area were determined. The absolute numbers varied from 13 to 2300 individuals/cm 3. All species or species groups but one, Lesquereusia spiralis, a species of nutrient-rich fen microsites, were found to occur in ombrotrophic sites. Only three species (Arc ella discoides, Bullinu/a indica, and Heleopera syfvatica) were not found in eutrophic sites, whereas the remaining taxa were widely distributed across the ecological gradient from ombrotrophic to eutrophic microsites. Three species, Amphitrema wrightianum, Arcella discoides, and Hya/osphenia e/egans were found to be in very low numbers in Sphagnum. All other testacean species were found to be well represented in both Sphagnum and Bryales mosses. Key words: Testate amoebae; Sphagnum mires; Range and weighted average analysis; Moisture regime; Nutrient regime; Vegetational gradients.

Introduction Testaceans are a group of amoeboid Protozoa in superclass Rhizopoda. This group is characterized by tests and shells which cover the entire body of the animal except for the naked pseudopodia used for locomotion and collection of food. Testaceans playa major role as decomposers of dead organic matter in soils. Consequently, testaceans are able to recycle the energy content stored in organic detritus back into higher levels of the food chain as a food source both directly for themselves and indirectly for other animals higher in the food chain (SLEIGH 1989). By performing this role in the ecosystem, testaceans are particularly abundant

in soils with high organic or humus content. In addition, they require water because the naked pseudopodium of the animal is unprotected from dessication (SLEIGH 1989). Therefore, testaceans arc among the most dominant components of the soil microfauna in mires, especially Sphagnum mires (e.g. HEAL 1962, 1964; TOLONEN 1966, 1986; WARNER 1987, 1989). Another important attribute of testaceans is the shell of these organisms. The shells are taxonomically diagnositic, resistant to decay, and can be recovered readily from fossil peat deposits and other geological sediments. Fossil testa-

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et al.

cean shells are important paleoenvironmental indicators (HARNISCH 1927; GROSPIETSCH 1953; TOLONEN 1966, 1967,1968; AABY 1976; BARBER 1981; BEYENS & CHARDEZ 1984; BEYENS 1985; TOLONEN et al. 1985). Testaceans can provide valuable paleoenvironmental information once their precise ecological tolerances are known. It has been suggested the presumed short geological history of testaceans habitats led to a low rate of speciation and rather broad ecological requirements of testaceans (FENCHEL 1987; BERZINS & STENSDOTTER 1990). However, recent studies have shown certain species may not have as wide ecological tolerances as once thought. For example, Bullinula indica is most common in xerophilous Sphagnum hummock habitats (TOLONEN 1986). Hyalosphenia subflava is confined to artificially drained mires in Finland (ToLONEN 1986) but it is found in virgin forested mires in Canada (WARNER & CHMIELEWSKI 1992). There is a growing literature on testacean ecology, especially on their population biology (e.g. LAMINGER et al. 1982; LoUSIER 1982; SMITH & HEADLAND 1983; SCHONBORN 1986). Few detailed studies exist on the community ecology of testaceans (MEISTERFELD 1977, 1978) probably, in part, due to the difficulty of accurately relating testacean distributions to specific ecological factors (BEY ENS et al. 1990). This study is one of the first attempts to determine ecological structure and favourable limits of testacean habitats in mires in southern Finland. In this paper, we use physical, chemical, and ecological variables and weighted average ordinations to characterize the autecology of testacean species represented along a continuum of microsite types. A second paper using multivariate analyses focuses on the synecological relationships (TOLONEN et al. 1993).

REINIKAINEN et al. 1984) is a small kettle mire with a wide range of microsite types and bryophyte communities. The Suurisuo mire complex near Janakkala is primarily minerotrophic and contains a wide range of microsite types and bryophytes (RUUHIJARVI 1979; LINDHOLM & VASANDER 1990). Lakkasuo near Orivesi is mostly ombrotrophic in its southern part and is fed by slow-moving minerotrophic water in the northern part of the basin (LAINE et al. 1986). The last mire is situated north of Lakkasuo near the University·of Helsinki Forestry Field Station at Hyytililii.. It is a small (0.3 ha) mesoeutrophic mire on the shore of Lake Kuivajiirvi. We follow the Finnish mire classification of RUUHIJARVI (1983), and the mire classification system of LAINE et al. (1986). Botanical nomenclature is that of HAMET-AHTI et al. (1984) for vascular plants, KOPONEN et aI. (1977) for bryophytes, and AHTI (1981) for lichens. A brief description of the sampling sites with special emphasis on the bottom layer vegetation is given in Appendix 2.

FINLAND

SWEDEN USSR

Material and Methods 1. Field studies Selection of study sites Six mires were chosen for this study for the following reasons. All of them are located within one-degree latitude thereby limiting wide variation in geographic distribution. There are a representative number of micro-site types within each mire including the major microsite types of southern Finnish mires. Similar microsite types occur in at least two or more mires. Finally, ecological data, continuously collected during the previous three years in most of the mires, are available for relating testacean distributions. The study sites are from the raised bog region of southern Finland (Fig. 1). They are situated between 61 0 and 6r N latitude and 24 0 and 25 0 31' E longitude. Two of these, Kaurastenuso and Laaviosuo are ombrotrophic raised bogs (VASANDER 1982; TOLONEN 1987). Heinisuo (Koski, HI.,

1

o

'

100

,

200km

Fig. 1. Map showing location of mire study sites. I = Kaurastensuo, Laaviosuo, and Heinisuo, 2 = Suurisuo, and 3 = Lakkasuo and Kuivajiirvi suo. The dashed line demarcates the region of raised bogs to the south and the region of aaprmires to the north (according to RUUHIJARVI 1983).

Ecology of Testaceans

Testacean field sampling Field sampling was conducted between 15 October and 10 November 1984. In the case of Lakkasuo, testaceans were sampled at previously established water level test sites where water table measurements had been monitored biweekly during the previous three years as part of another ecological study by LAINE et al. (1984); the mean value of the medians of water level for each year was used in our study. For the other mires, the water table values for the 1984 sampling period were used. A one-meter square quadrat was placed at each microsite and general notes on the vegetation were made. Four replicate samples, one from each comer in the quadrat was cut with a sharped stainless steel cylinder (12 cm diameter). In Sphagnum vegetation, the portion below the upper actively growing chlorophyllous segment and that above the peat and decomposing horizon were carefully clipped with scissors from each cylinder sample and taken for testacean analysis. All four samples were then amalgamated to form a single representative sample. Testacean samples were collected in this manner to avoid vertical variation in testaceans known to occur between the chlorophyllous and non-chlorophy}lous segments of the Sphagnum stem (SCHON BORN 1963; MEISTERFELD 1977). In the case of other vegetation types, the upper soil horizon or only forest litter was collected from each cylinder sample. A fIfth cylinder sample at equivalent depth as the testacean samples was collected from the center of the quadrat for bulk density detenninantions. Finally, a water sample was collected from the quadrat for later analysis of various chemical constituents.

121

1108 Elemental Analyzer following the DIN 51708-78 standard: the acceptable deviation for the replicates from the mean ofN is ± 0.1 % and from themeanofC±O.4%, respectively. Each sample was burnt at 1030°C to separate the gases and then each gas was measured with a chromatograph. Testacean analyses: Samples for testacean analysis were prepared for quantitative estimates of abundance. Each fresh peat sample was homogenized and then split into two halves. Subsample A was weighed to obtain the fresh weight and then dried to a constant weight in the drying room for calculation of bulk density dry weight. A volume of 2 ml was measured with a modified plastic syringe for subsample B, weighed to at least one milligram accuracy, and then placed in a 50 ml glass beaker. The sample was boiled in water for about 5 to 10 minutes, while constantly stirring with glass rod. At the outset of boiling, two tablets each containing 11,300 ± 400 Lycopodium clavatum spores (STOCKMARR 1971; Lund University Batch No. 201890) were added to each sample. After boiling, the sample was passed through a coarse sieve with mesh diameter 750 f.lm to remove all coarse detritus. Testacean shells were then concentrated in a centrifuge (2000 rpm) for about 2 minutes, and then stored in glycerine and safranin stain in stoppered vials. A drop of the testacean concentrate was placed on a glass slide for microscopic analysis. Each coverslip was systematically scanned at either 300 x or 600 x magnification using both bright field and phase contrast. All testacean shells were identificd and tabulatcd. Data are presentcd as relative percentages. Absolute numbers per cm 3 fresh sample were estimated using the following formula: No. of fossil tests counted No. exotic spores added ------------------x ---------------No. cxotic spores counted Weight of frcsh sample

2. Laboratory studies Water analysis: Unfiltered water samples were returned to the laboratory and left to stand for several hours until reaching room temperature. Measurements for pH were taken with on Orion Research Digital pH meter, Model 701, and for electrolytic conductivity with a Radiometer conductivity meter, Model COM 3. All conductivity measurements were corrected for temperature 20°C and reduced for hydrogen ionization. Each water sample was passed through sterilized cotton gauze and subsequently through Whatman GF/C glass microfibre ftlters. Samples were frozen until analyses for dissolved organic carbon (DOC) in a high temperature combustion chamber and by IRGA following SALONEN (1979), and for total calcium by means of the AAS (perkin Elmer) technique. Bulk density measurements: Each peat sample was weighed to 1 mg accuracy immediately upon arrival to the laboratory, then placed in paper bags and a drying room at about 60°C until a constant dry weight was attained. The percentage water content and bulk density dry weight were calculated. Carbon and nitrogen: Total carbon and total nitrogen in the moss material or surface peat were determined at the State Technical Research Centre in Jyvasky!.ii, Finland. Three or four replicates from each sample were analyzed by a Carlo-Erba

The weight of the fresh moss samples are corrected for bulk density by: weight of testate amoebae sample (gm) bulk density wet weight (gm/cm 3 ) Generally, wc follow the taxonomy of GROSPIETSCH (1958) for testacean identifications. Further notes are given in Appendix l.

3. Data analysis An initial analysis of distribution of testaceans with respect to the environmental parameters produced a very wide scatter which was not normally distributed. Therefore the data were transformed to weighted averages using thc equation of OKSANEN et al. (1988). The weighted average (wi) for species i which occurs at abundance yij at site j where the quantity of ecological factor X e.g. pH is xj, is defined by: wi

= I:yijxj/I:yij,

The weighted standard deviation (si): si =

«~yijxj2

-

(~yijxj)2/~yij)/I:yij)Y2.

122

K.

TOLONEN

et aI.

4. The study sites and their ecological characteristics

S. lindbergii S. magellanicum S. majus

Testacean sample sites could be classified into four main nutritionaJ classes on the basis of the vegetation cover (tree versus herb versus moss layer): ombrotrophic, oligotrophic (Le. oligominerotrophic), mesotrophic, and eutrophic. The basis for this division is the well-established relationship between certain mire vascular plant and moss species and the nutrient status of peat soil (ct. EUROLA et aJ. 1984 and references therein). Measured vaJues for pH, caJcium, nitrogen, and total concentration of electrolytes (conductivity) collected in this study (Table I) conformed with this division as established in numerous studies.

Among the 30 samples collected from Bryales mosses, the dominant moss types were:

Table 1. Summary statistics (mean and S.D. in brackets) of selected environmentaJ parameters for each of the four main trophic categories based on floristic characteristics of the sampling sites. A = ombrotrophic, B = oligo-minerotrophic, C = mesotrophic, and D = eutrophic. Statistically significant (p<0.05) differences (Tukey's test) of certain environmenta,l parameters between the trophy classes are indicated by different superscripts (a-d). Trophy class

A B C D (n= 32) (n=28) (n= 15) (n= 15)

pH

3.79a (0.11) 5.48 (19.9)

4.58b (0.57) 30.0b (17.8)

Ca (mg· I-I)

1.6a (0.8)

3.2b (1.9)

N (% 'dw- I )

0.67(0.21)

C:N ratio

77.48 (24.S)

DOC (mgC·l- l )

40.9 8 (13.2)

1.15 bcd (0.4) 46.0bed (16.6) 24.0bed (13.4)

Condo

(flS· cm -2)

5.18c (0.51) 26.9c (11.0) 2.7ac (O.S) 0.9S bed (0.25) 48.0 bed (12.7) 17.4bed (7.9)

5.72d (0.42) 63.1 d (47.1) 4.9 d (2.1) 1.31 bed (0.47) 39.1 bed (14.7) 20.0bed (7.4)

Of particular importance in considering testacean distributions is the type of ground cover. Of our 90 samples, 70 were in Sphagnum, 17 in Bryales mosses, and 3 from lichen surfaces. Among the Sphagnum samples, 28 species were present as indicated below by the number of samples: S. angustijolium S. annulatum S. balticum S. centrale S. cuspidatum S. fallax S. Jimbriatum S. flexuosum S. fuscum S. girgensohnii S. jensenii

(15) (1)

(7) (4) (3) (2)

(1)

(1) (10) (3) (I)

S. S. S. S. S. S. S. S. S. S. S.

nemoreum obtusum papillosum platyphyllum riparium rubellum russowii subfulvum subsecundum subnitens tenellum

(3) (2) (2) (1)

(4) (I)

(2) (2) (2) (1)

(2)

(I)

(4) (4)

Aulacomnium palustre (1) Campylium stellatum (1) Calliergon stramineum (1) Cinclidium stygium (1) Climacium dendroides (I) Dicranum undulatum (2) Drepanocladus exannuhitus(3) D. procerus (1)

S. teres S. warnstorfii S. wulfianum

D. revolvens Paludella squarrosa Pleurozium sc,hreberi Pseudobryum cinclidioides Polytrichum commune Rhytidiadelphus triguetrus Scorpidium scorpioides Tomentypnum nitens

(3) (7) (1)

(2) (1)

(4) (1)

(2) (1)

(1) (1)

One liverwort, Plagiochila asplenioides, was dominant in a single sample, while the lichens Cladina rangijerina, C. arbuscula and Cetraria islandica were each abundant in one sample.

Results 1. Faunal composition A total of 41 testacean species or agglomerative species groups which are difficult to differentiate, were encountered in this study. Only 37 of these and the rotifer Habrotrocha angusticollis, were included in statistical treatments. The remaining four testacean species were omitted because they were present in only a few samples. A few brief comments on microsite characteristics where they were found follow. Hya/osphenia subfiava H. subflava was present in only one sample. The estimated

abundanc~ is SOl individuals per cm3 peat. The sample is

from an ombriotrophic, low Sphagnum fuscum hummock in Lakkasuo (WT 17 cm, water content 91.5%, pH 3.84, condo 39.0 IlS . cm- 2 , DOC 42.4 mg C . I-I, Ca 2.52 mg . I-I, N 0.6%· dw- I , C: N 66.3, depth 4-6.5 cm, Db 12.1 g . dm- 3 ). Dijjlugia rubescens D. rubescens occurred in two samples with about 90 and 210 individuals/ cm3 . Both samples were in minerotrophic lawns in Sphagnum angustifolium (pH 4.95) and in Drepanocladus intermedius (pH 6.25). Respectively, the WT was 10 cm and 23 cm, water content 94.8 and 95.6%, DOC 15.2 and 9.9 mgC . I-I, Ca 1.69 and 8.51 mg . I-I, NO.7 and 1.8% . dw- I , C: N 62.1 and 25.5. Cyphodera ampul/ea

C. ampullea occurred sporadically in low numbers (from 24 to 150 individuals/cm3) in only four samples, three of which were in minerotrophic lawns and one from an

123

Ecology of Testaceans 6000

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Fig. 2. Distribution of six testacean species (ind./cm) peal, y-axis) versus the trophy level of the site based on vegetation composition (eutrophic through ombrotrophic). Single observations are indicated with dots, and numbers are the number of observations greater than I. AmpIIitnInIe IJIMm

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Fig. 3. Distribution of six testacean species (ind./cm 3 peal , y-axis) versus the calcium content of water (mg '1- 1, x-axis). See Fig. 2.

ombrotrophic Sphagnum balticum hollow in Laaviosuo. The mean values of the other ecological variables were WT 6.25 ± 5.7 em (2-12 cm), water content 95.9 ± 1.6% fresh wr (93.7-97.1 %), pH 5.17± 1.00 (3.76-6.02), DOC IS.9±14.4mgC·I- 1 (9.7-41.4), Ca 2.5±1.9 (1.6-5.4) mg' 1-1 ,N 1.0±0.34 (0.S-1.3)% 'dw- I , C:N 44.7± 11.0 (33.S-54.7).

ladus procerus: WT 21.2 ± 20.9 cm (0-60 cm), water content 9O.S±I1.6% (70.2-97 .1%), pH 5.3±l.O (3.9-5 .9), Ca 4.2±2.2 (1.9-6.2) mg· I-I, N 1.3±0.5 (0.S-2.0)% . dw- I , C : N 50.0± 19.5 (22.9-62.2).

Cryptodifflugia oviformis-typc

The distribution and the absolute numbers of some of the identified Protozoan taxa along this gradient is shown in Fig . 2. The weighted averages for the distribution of the species along the trophy gradient are listed in Table 2.

Five minerotrophic samples proved to contain C. oviformis four of which come from fairly dry habitats and one from relatively wet meso-eutrophic fen site with e.g. Drepanoc-

2. Trophy of the site type

124

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TOLONEN

et aI.

Table 2. Weighted averages 0N A) of trophy level for dif-

ferent species with standard deviation (S.D.) and minimum and maximum values. n = number of observations. In the oligo-minerotrophy = 2, calculation, ombrotrophy = 1, meso-minerotrophy = 3, and eutrophy = 4.

Species

n

WA S.D. min max

Amphitrema jlavum Bullinula indica Phryganella acropodia Difflugia leidyi Assulina muscorum Heleopera sylvatica Amphitrema wrightianum Assulina seminulum Nebela griseola Nebela militaris Trigonopyxis arcula Arcella rotundata var. aplanata Placocista spinosa Hyalosphenia papi/io Nebela tincta Corythium dubium-type Arcella discoides Hyalosphenia elegans Hyalosphenia ovalis Nebela parvula Cyclopyxis arcelloides-type Arcella catinus Centropyxis cassis-type Euglypha tuberculata Nebela carinata Arcella artocrea-type Euglypha rotunda Euglypha strigosa Heleopera sphagni Heleopera petricola Difflugia bacillifera Sphenoderia lenta Quadrula symmetrica Habrotrocha angusticollis Nebela marginata Centropyxis aculeata-type Lesquereusia spiralis Nebela lageniformis

36 28 15 69 31 7 32 21 51 37 26

1.2 1.2 1.3 1.4 1.5 1.5 1.5 1.5 1.5 1.6 1.6 1.6

0.62 0.64 0.55 0.73 0.71 0.70 0.79 0.92 0.71 0.72 0.69 0.93

1 1

5 37 40 48 6 22 15 28 70 34 43 39 20 10 28 21 40 20 10 14 8 36 12 41 5 6

1.6 1.6 1.7 1.7 1.7 1.7 1.8 1.8 1.9 1.9 2.0 2.0 2.1 2.1 2.1 2.2 2.2 2.3 2.4 2.4 2.6 2.8 2.9 2.9 3.6 3.7

1.20 0.84 0.54 0.79 0.95 0.86 0.68 0.77 0.72 1.08 0.87 0.95 l.l8 1.25 0.95 0.86 1.04 1.17 1.07 0.74 1.00 1.22 1.05 0.97 0.48 0.80

1 1

to

1

1 1

1 1 1 1 1

1

1 1 1 1

1 1 1

1 I 1 1

1 1 I

1 1 3 1

4 3 4 4 4 3 4 4 4 4 4 4 4 4 4

4 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4

4 4

Table 3. Weighted averages 0N A) of the water calcium content (mg '1- 1) for different species with standard deviations (S.D.) and minimum and maximum values. n = number of observations.

Species Amphitrema jlavum Amphitrema wrightianum Bullinula indica Nebela griseola Difflugia Leidyi Phryganella acropodia Arcella artocrea-type Nebela carinata Hyalosphenia ovalis Hyalosphenia papilio Hyalosphenia elegans Arcella discoides Centropyxis cassis-type Assulina seminuLum Assulina muscorum Heleopera sylvatica Trigonopyxis arcula Nebela militaris Quadrula symmetrica Heleopera sphagni Nebela tincta Arcella catinus Heleopera petricola Arcella rotundata var. aplanata Cenrropyxis aculeata-type Corythium dubium-type Nebela marginata Difflugia bacillifera Euglypha tuberculata Habrotrocha angusticollis Cyclopyxis arcelloides-type Nebela parvuftl Euglypha rotunda Euglypha strigosa Lesquereusia spiralis Placocista spinosa Sphenoderia Zenta . Nebela lageniformis

n

WA S.D. min max

33 7 10

1.3 3.4 1.4 1.6 1.8 1.8 1.8 1.9 2.0 2.1 2.1 2.1 2.2 2.2 2.2 2.3 2.3 2.3 2.4 2.4 2.5 2.5 2.5 2.6 2.8 2.9 3.0 3.0 3.0 3.1 3.1 3.2 3.2 3.5 3.7 5.4 6.0 6.3

19 12

26 10

18 13 34 19

5

41

27

63 28

34

47 8 38 37 30 20 24 40 44

11 10 36 34 64 26 25 21

5 3 13 6

0.83 0.91 0.57 0.64 0.49 0.71 1.25 1.49 1.06 0.95 0.98 1.07 1.26 1.52 1.30 0.80 2.29 1.45 1.18 1.49 1.76 1.21 1.65 1.63 1.24 1.91 1.53 2.09 1.64 2.02 2.28 1.90 2.15 1.47 1.8 2.43 3.15 1.69

0.3 0.7 0.7 0.7 0.7 1.0 1.0 0.3 0.3 0.3 0.7 1.2 1.0 0.7 0.3 0.7 0.7 0.7 1.2 0.7 0.7 0.7 0.3 0.7 1.2 0.7 1.7 0.7 0.7 0.7 0.3 0.7 1.2 0.7 1.9 0.7 1.4 1.8

8.5 6.2 3.4 5.4 3.4 6.8 6.8 5.9 8.5 6.2 4.8 3.9 8.2 9.4 9.4 5.4 9.4 9.4 8.5 6.8 9.4 6.8 5.0 8.5 8.5 9.4 6.2 6.2 8.5 8.5 9.4 9.4 9.4 8.2 6.2 6.8 9.4 8.5

4 4

Even if the relatively small number of the sampling sites does not allow very detailed conclusions, certain general features are evident. Among the 37 testacean taxa treated, only one species (Lesquereusia spiralis) was missing in ombrotrophic and oligominerotrophic sites and only three species (Arcella discoides, Bullinula indica and Heleopera sylvatica) were absent in eutrophic sites. Several taxa possessed a more or less similar frequency

through the four mire site type groups, for example Centropyxis aculeata-type, C. cassis-type, Difflugia bacillilera, Eug/ypha tuberculata, Heleopera petrico/a, H. sphagni, Nebela carinata, N. marginata and Quadrula symmetrica. Two taxa exhibited a preference to eutrophic sites: NebeLa lageniformis and (rotifer) Habrotrocha angusticollis, whereas most of the taxa seemed to have preference to ombrotrophy. Examples of this group included: Amphitrema jlavum, A. wrightianum, Assulina muscorum, A. seminuLum, Corythion dubium-type, Difflugia

Ecology of Testaceans

leidy;, Euglypha strigosa, Nebela militaris and Phryganelfa acropodia. Hence it seems that the often used division of mire testaceans to bog species and fen species hardly is valid in south Finnish mires.

3. Water calcium The weighted average calcium content of mire water at the sample sites varied from 1.31 ± 0.83 mg . 1- 1 (S. D.) for Amphitrema flavum to 6.26 ± 1.69 mg . 1- 1 for Nebefa Table 4. Weighted averages (W A) of water pH for different species with standard deviations (S.D.) and minimum and maximum values. n = number of observations. Species

n

WA S.D. min max

Difflugia leidyi Bullinula indica Phryganella acropodia Amphitrema flavum AssuIina seminulum Assulina muscorum NebeIa miliwris ArcelIa disco ides Heleopera sylvatica Amphitrema wrightianum Corythium dubium-type P/acocisw spinosa Trigonopyxis arcula Arcella rotundata var. ap/anata Nebe/a tincw Hyalosphenia papilio Hya/osphenia elegans NebeIa griseoIa NebeIa parvula Hyalosphenia ovalis Euglypha tuberculata Cyclopyxis arcelloides-type Arcella catinus Centropyxis cassis-type Nebela carinaUl. Euglypha strigosa Arcella anocrea-type Euglypha rotunda Heleopera petricola Heleopera sphagni Difflugia bacillifera Sphenoderia lenta Habrotrocha angusticollis Centropyxis aculeata-type Quadrula symmetrica NebeIa marginaw Lesquereusia. spiralis NebeIa Iageniformis

15 to 28 36 32

3.9 3.9 3.9 4.0 4.0 4.0 4.1 4.1 4.1 4.1 4.1 4.2 4.2 4.2

0.23 0.:t9 0.30 0.49 0.48 0.50 0.51 0.50 0.51 0.53 0.56 0.85 0.54 0.82

3.5 3.7 3.7 3.7 3.5 3.5 3.5 3.7 3.5 3.8 3.5 3.7 3.6 3.5

4.8 5.6 5.8 6.3 6.3 6.0 6.3 5.3 6.0 5.9 6.3 5.9 5.9 6.3

4.2 4.3 4.3 4.3 4.4 4.4 4.4 4.4 4.5 4.5 4.5 4.6 4.6 4.6 4.6 4.7 4.8 5.0 5.0 5. t 5.2 5.3 5.4 5.8

0.48 0.63 0.64 0.65 0.58 0.64 0.69 0.68 0.74 0.73 0.87 0.66 0.86 0.80 0.72 0.73 0.81 0.60 0.81 0.59 0.46 0.72 0.39 0.47

3.5 3.7 3.5 3.7 3.7 3.8 3.5 3.5 3.7 3.6 3.7 3.5 3.6 3.5 3.8 3.7 3.9 3.6 3.9 3.9 3.9 3.8 4.3 3.9

6.3 6.3 6.1 5.8 6.3 6.3 6.3 6.3 5.9 6.3 6.3 6.3 5.9 6.3

10 Arcb. Protistenkd., Bd. 142, 3-4

68

51 6 31 7 48 5 37 26 39 37 22 21 28 15 38 69 34 42 20 21 to 27 20

40

10

14 36 41 8 12 5 6

5.8

6.3 5.8 6.3 6.3 6.3 6.3 6.0

5.9 6.3

l25

iagenijormis .(fable 3). Whilst the average figures show a clear gradient, the range figures are almost the same for many taxa. Exceptions are those most characteristic of ombrotrophic conditions, with low water calcium content, such as Difflugia leidyi, Bullinula indica, Hyalosphenia eiegans, H. ovalis, Phryganella acropodia and Nebela griseola as well as a few species with clear preference to eutrophic (i.e. nutrient-rich with high water c1acium content) habitats : Lesquereusia spiralis, Sphenoderia lenta and Nebefa lageniformis (Fig. 3).

4. Water pH This parameter is an integrated measure of the nutritional conditions in peatlands (for plants at least). It was significantly correlated with the trophy group (r = 0.860***), water calcium (r= 0.557***), the electrolyte content (conductivity) of water (0.586***), and the water nitrogen (r = 0 .5 08***). The average pH value for the sites of individual taxa varied from 3.85 ± 0.23 (Dijjlugia leidyi) to 5.77 ± 0.47 (Nebela lagenijormis) (Table 4). For most species the average pH seems to be the ecological optimum value because the occurrence of the given species often is fairly normally distributed around it. Scattergrams for six species are given as examples (Fig . 4). Species with a strong ombrotrophic preference exhibit skewed frequence distribution, the peak occurrence being below or close to pH 4.0 (cf. Bullinula indica, Phryganella acropodia and Amphitrema flavum, in Fig. 4).

5. Soil nitrogen The. total nitrogen content of the surface peat is a good indicator of the fertility of the mire site in terms of the vegetation (e.g. WESTMAN 1981). In the present material the total N-concentration varied from 0.35 to 2.10 per cent of dry matter (Table 5). The order of taxa and distribution pattern are almost the same as above in pH and Ca and the range of occurrence along this gradient is very wide within all species. Notably wide amplitudes are true, for example, for Nebela militaris and N. tincta (Fig. 5; Table 5).

6. Soil C: N ratio Due to the great variation in the nitrogen content of peat soils of different sampling sites plus to a lesser extent to variation in the soil carbon content the C: N ratio of the samples varied from 22.3 to 134.0, being highest on the ombrotrophic sites (Fig. 6; Table 6) . Again, the species that are widely distributed along the nutrient-trophy gradient exhibit a wide amplitude in the C : N ration of the substrate, e.g., Euglypha tuberculata,

126

K . TOLONEN

cl

aI.

AmphItrama IIavum 6000

Euglypha tubeIW/8fa

Centropyxts acuIaaIB

2000

0

1500

0

4000

1000

0

•

2000

0 0200 2

o 3

0

.. ..

.

-ZZ

4

3

1000

5

0

6

.. .-·. . ..........

0

4

3

Zo .. 0

0

Zo

'Z-

0

..

.-. .-o. ..

500 o .. ·Z_ ZZ0

0

0

6

5

7

3

4

7

6

5

0

500

z-.

..

Z

•

6

Sphellodelfe Ienta

1000

...

-2

00

5

• 0

0

500

0

•

0

.

Phryrpme/ItI M:ropOd/II

o.

_.0

0

4

3

1000

.

.0

••

500

0

0

7

He/eopere .pheflnf

1000

.. ....•

0

0

0

7

o

4

3

0

0

20" 0

0

6

5

7

0

0

3

4

6

5

7

Fig. 4. Distribution of six testacean species (ind.lcm 3 peat, y-axis) versus the pH of water (x-axis) . See Fig. 2.

6000

/lmphltTema fIavum

7500

4000

• le . . . 2

3.

.n. ...

0 0.0

.. ..

1.0

2500

2000

DiMIgIa leidy/

1000

0

2'

2 1_ llJJI... JIe • . . . • • • • •

2.0

0.0

"10 dw "

1.0

0.0

2.0

1000

z ••

0

PhtyganeI/8 acropodill

NebeIa mllitarlB

6000

...........•.

5000

.

2000

CenttopyIds lIICeIIoIdes

1000

2

1.0

Sphenoderle Ient8

• •

4000

•

2000 0

2

0.0

• .2 .:a.n

2

... . ..... •

1.0

.-••• • . ...

500

••

2

2.0

0 0.0

1.0

. ...

•z 2.0

0.0

1.0

2.0

•

.. .

2.0

Fig. S. Distribution of six testaccan species (ind.lcm 3 peat, y-axis) versus the nitrogen content of peat (N %. dw- 1, x-

axis). See Fig. 2.

Nebela militaris, whilst the taxa with ombrotrophic preference (Difflugia leidyi, Amphitrema wrightianum, Bullinukl indica) or meso-eutrophic (Habrotrocha angusticollis, Lesquereusia spiralis) have a narrower amplitude .

trate, however, the order of species and the width of the amplitude along this (Fig. 7; Table 7). Difflugia leidyi occurs with the lowest figures, 0.4 ± 11. 9,..s . cm - 2 . Other examples from habitats with low electrolyte content are Bullinukl indica, Amphitrema wrightianum, Arcella discoides, and Arcella rotundata var. apklnata.

7. Specific electrolytic conductivity of water The electrolytic conductivity of water as corrected for the activity of H+ ions is a measure of the content of electrolytes. Negative figures are errors resulting from the inaccuracies in the determination of pH. The data illus-

8. Dissolved organic carbon (DOC) of water Most species had a very wide range along this environmental gradient and did not exhibit any clear optimum,

Ecology of Testaceans

Table S. Weighted averages (WA) of peat nitrogen content (%. dw- I ) for different species with standard deviations (S.D.) and minimum and maximum values. n = number of observations. Species

n

WA S.D. min max

Placocista spirwsa HyaJosphenia elegans Bullinula indica Amphitrema flavum Difflugia leidy; Phryganella acropodia Hyalosphenia papilio Arcella discoides Amphitrema wrighlianum Arcella rotundata var.

4 20 6 32 15 25 34 6 6

0.5 0.6 0.6 0.6 0.7 0.7 0.7 0.7 0.7 0.8

0.15 0.18 0.13 0.23 0.13 0.20 0.23 0.20 0.14 0.28

0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.6 0.4

1.1 0.9 0.9 1.9 1.0 1.4 2.0 1.1 1.0 2.0

Assulina seminulum HyaJosphenia ovalis Difflugia bacillifera Heleopera sylvatica Arcella catinus Nebeia marginata Nebeia griseoia Heleopera petricoia Heleopera sphagni Euglypha strigosa Assulina muscorum Nebela militaris Euglypha tuberculata Trigonopyxis arcula Arcella artocrea-type Nebeia carinata Nebeia parvula Nebela tincta Euglypha rotunda Centropyxis aculeata-type Corythium dubium-type Nebela iagent/ormis Quadrula symmetrica Cyclopyxis arcelloides-type Habrotrocha angusticollis Centropyxis cassis-type Sphenoderia lenta Lesquereusia spiralis

29 12 9 27 29

0.8 0.8 0.8 0.8 0.9 0.9 0.9 0.9 1.0 2.0 1.0 1.0 1.0 1.0 1.0 1.1 1.1 I.l 1.1 1.1 1.1 1.2 1.2 1.2 1.3 1.3 1.3 1.4

0.32 0.33 0.34 0.27 0.24 0.25 0.32 0.28 0.37 0.24 0.36 0.36 0.49 0.33 0.30 0.44 0.26 0.34 0.48 0.37 0.53 0.40 0.20 0.39 0.40 0.37 0.34 0.21

0.4 0.4 0.4 0.4 0.4 0.7 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.5 0.6 0.4 0.4 0.4 0.5 0.5 0.4 0.8 0.5 0.4 0.5 0.5 0.4 0.9

1.9 1.8 1.4 1.9 1.9 2.1 1.5 1.6 2.0 1.8 2.0 2.0 2.0 1.9 1.6 2.1 2.0 2.0 2.0 2.1 2.0 1.8 2.0 2.1 2.1 2.1 2.0 1.6

aplanata

24

11

21 18 37 21 62 46 37 33 8 18 24 35 23 37 43 5 8 62 31 37 14 4

although the mean figures varied from 14.6 to 45.4 mg . C . I-I (Table 8, Fig. 7). Notable exceptions were found among some species that occurred within less coloured water: e.g. Sphenoderia tenia (average 14.6, max. 48.9 mg C . I-I), Nebela marginata (average 15.2, max. 55.6mg C· I-I), Quadrula symmetrica (average 17.1, max. 27.3 mg C . 1-1) and Lesquereusia spiralis (average 19.4, max. 28.7 mg C . I-I). The other end of the gradient was characterized by Bullinula indica, Heleopera sylvatica and Assulina muscorum. 10*

127

Table 6. Weighted averages (WA) of peat C: N ratio for different species with standard deviations (S.D.) and minimum and maximum values. n = number of observations. Species

n

WA

S.D.

Lesquereusia spiralis (2~rula SYn1n1etrica Habrotrocha angusticollis Spherwderia Lenta Nebela lageniformis Centropyxis cassis-type Cyclopyxis arcelloides-

4 8 31 14 5 37 62

31.0 39.1 40.2 40.4 41.1 41.3 42.9

7.72 23.7 51.1 9.46 22.9 92.4 16.10 22.3 98.3 16.94 22.9 128.4 12.50 22.5 61.9 14.01 22.3 95.3 17.50 22.3 134.0

37 23 35 8 33 18 43 21 46 11 18 62 37 37 29 21 27 6 9 24

43.8 48.5 49.1 49.2 49.2 51.7 51.7 52.6 53.6 53.7 54.3 55.1 56.7 57.4 58.7 59.8 59.9 62.9 65.5 65.9 67.4

13.29 17.55 19.34 18.35 13.15 15.44 24.18 27.3 20.08 17.22 12.68 18.07 21.53 26.18 27.11 18.82 23.71 18.80 10.07 40.47 24.19

22.3 22.5 22.5 22.9 23.7 26.9 22.3 25.3 25.5 22.9 22.3 23.7 26.4 25.5 22.3 27.1 31.3 27.1 48.2 31.7 22.9

98.3 134.0 95.3 134.0 66.3 100.6 134.0 134.0 134.0 134.0 72.4 134.0 134.0 134.0 134.0 134.0 134.0 134.0 73.0 134.0 134.0

12 29 6 15 25 34 6 32 20 4

68.0 71.7 72.7 73.7 73.8 74.2 79.7 85.2 88.9 93.2

26.72 27.43 21.69 14.29 20.53 26.88 13.00 31.63 29.08 21.20

25.5 25.5 42.2 48.2 34.4 22.9 55.8 25.5 45.9 42.2

134.0 134.0 110.9 128.4 134.0 134.0 134.0 134.0 134.0 110.9

min

max

type

Centropyxis aculeata-type Nebela parvula Euglypha rotundata Nebela tincta Arcelia artocrea-type Trigonopyxis arcula Nebeia carinata Corythium dubium-type Euglypha strigosa Nebeia militaris Nebeia marginata Heleopera petricoia Assulina muscorum Euglypha tuberculala Heleopera sphagni Arcelia catinus Nebela griseoia Heleopera sylvatica Amphitrema wrightianum DifJlugia bacilli/era Arcella rOlunduta var. aplanata Hyalosphenia ovalis Assulina seminuLum Arcella disco ides DifJlugia leidyi Phryganella acropodia Hyalosphenia papilio Bullinula indica Amphitrema jlavum Hyalosphenia elegans Placocista spinosa

24

9. Depth to water table As seen from some examples in the scattergrams (Fig. 9) most of the species seemed to have a certain water table optimum around which they were more or less evenly distributed. Therefore the mean values of Table 9 that are ranking the species along this environmental factor may give an approximation about the response of the taxa to moisture providing that the water table within sampling was a representative one. The Lakkasuo data, where the

128 10000

K.

TOLONEN

Assu/lna muscorum

. -.....

5000

. . · · 2 2.....

0

2_2_222_12_2e2 •

0

2000

ct al.

SO

2000

• . ...

CentlOpylCis arceJJoides

7500 SOOO

. .. • .

1000

·• •·.. ....

• • 2

SO

0

DifflugiB leidy;

0

_2.~

0

ISO

100

ISO

4000

.

0

0

SO

-

- ..

0

2

100

ISO

0

0

SO

-. 100

ISO

100

ISO

1000

.._...

2000

22-2e12eeZ2322- 2_

PhrygBne/fII acropodia

Nebefa ml/itBris

6000

1000

.. ..... ....

2500

.2•

2.

100

Centropyxis ~UIe8I8

..... .

2•

)

~

02

0

100

SO

..... .... •.

500

ISO

0

SO

3

Fig. 6. Distribution of six testacean species (ind.lcm peat, y-axis) versus the ClN-ratio of peat peat (x-axis). See Fig. 2.

6000

AnJphitJema flsvum

4000

600

200

23 ••

22. 2

0

so

1500

100

ISO

200

.

·2

500 I

-SO

•

•• 2. . .

_5,2 . . .

• 2

0

SO

1000

... 100

•

0

200

250

2500

·50

..~

0

100

ISO

200

.''''''1SZ1Z2

-SO

2SO

4000

. .......

·

100

ISO

200

250

100

150

200

2SO

SO

.... . ··2 _.

2000

•2

50

0

Hebe/a fJBI'tUlum

• ele .34la • • •

0

.. ....

.2 •

• • 2_

2

SO

Centropyx/s arcel/oides

5000

He/sops!S BphBgni

500

lSO

33) • •

0

2SO Jl S em" - 50

Eug/yphB tubflrCu/atB

1000

. .)2

0

6U.2' • •

-SO

7500

.• .. • .· .. . ·

400

.

2000

·.

Arcelfa cat/nus

2

22

100

lSO

200

250

·SO

2.

SO

Fig. 7. Distribution of six tcstacean species (ind.lcm 3 peat, y-axis) versus the H+ -corrected electric conductivity of water (flS·cm-2, a120°C, x-axis). See Fig. 2.

water table measurements also covered biweekly observations during the snow free period through three years show that the true range towards the lower WT is notable greater within most of the species (some examples in Fig. 10). On the basis of the weighted average figures the five species from the sites with the highest water table were: Amphitrema wrightianum, Nebela carinata, Lesquereusia spiralis, DijJlugia leidyi and Amphitrema jlavum and correspondingly the first five species from the "driest" sites were Nebela tineta, Cyclopyxis arcelloides-type, Trigonopyxis arcula, Nebela lageniformis and Centropyxis cassis-type (Table 9).

10. Moisture content within sampling The species ranking based on this parameter (Table 10) was in general quite close to that on the basis of water table (Table 9). Bullinula indica was, however, an exception. On the basis of the weighted average moisture content within sampling it prefers the "driest" sites but in the average WT statistics it lies in the middle of the species list. The explanation may be that Bullinula indica prefers lichenous surfaces that tend to be desiccated quickly as soon as the water table sinks below a given level. The overall distribution pattern of individual taxa was, how-

Ecology of Testaceans

129

Table 7. Weighted averages (WA) of reduced (i.e. H+ corrected electric conductivity of water (!AS . cm -2 at + 20°C) for different species with standard deviations (S.D.) and minimum and maximum values. n = number of observations.

Table 8. Wcighted averages (WA) of dissolved organic carbon in mire water (mg c· I-I) for different species with standard deviations (S.D.) and minimum and maximum values. n=number of observations.

Species

n

Specics

n

WA

Dijflugia leidyi Bullinula indica Amphitrema wrightianum Arcella discoides Arcella rotundata var. aplanata Amphitrema jlavum Placocista spinosa Hyalosphenia papilio Hyalosphenia e/egans Phryganella acropodia Assulina seminulum Difflugia bacillifera Assulina muscorum Nebela griseola Corythium dubium-type Heleopera petricola Hyalosphenia ovalis Heleopera sphagni Quadrula symmetrica Lesquereusia spiralis Euglypha tubereulata Euglypha slrigosa HeLeopera sylvatica Nebela militaris Areella artocrea-type Nebela tincta Cyclopyxis arcelloides-

7 8 5 3 20

Sphenoderia lenta Nebela marginata Quadrula symmetriea Lesquereusia spira/is Difflugia bacillifera Centropyxis aeuleata-type EugLypha strigosa Heleopera petricola Habrotroeha angusticollis Nebela earinata Nebela lageniformis Cyclopyxis arcelloidestype Heleopera sphagni Euglypha rotunda Arcella rotundata var. aplanata Amphitrema wrightianum Arcella discoides Plaeocista spinosa Difflugia leidyi Amphitrema flavum Assulina seminulum Hyalosphenia elegans Hyalosphenia papilio Euglypha tubereulata Nebela parvula Hyalosphenia ovalis Centropyxis cassis-type Corythium dubium-typc Nebela griseola Arcelia artocrea-type Arcella catinus Trigonopyxis areula Nebela militaris Nebela tineta PhryganeLla aeropodia Assulina muscorum Heleopera sylvatica Bullinula indica

13 12 8 5 10 40 20 20 34 18 6 61

14.6 7.10 15.2 4.78 17. I 5.15 19.4 3.69 21.0 10.91 21.2 8.06 21.4 8.40 21.6 7.10 23.5 10.86 24.1 8.89 25.3 5.86 26.3 16.61

38 24 21

26.3 12.25 26.6 15.51 27.2 15.18

type

Arcella eatinus Trigonopyxis areula Centropyxis cassis-type Nebela marginata Habrotrocha angustieollis Nebela parvula Euglypha rotunda Centropyxis aculeata-type Nebela carinata Sphenoderia Lenta Nebela lageniformis

WA

S.D.

min

0.4 0.5 2.2 3.4 6.9

11.92 23.51 10.18 17.38 26.13

-16.0 -16.0 -7.5 -9.0 -16.0

27.5 54.2 55.0 44.0 89.0

29 3 30 15 18 23 7 52 16 36 18 13 36 8 5 30 15 28 42 9 34 57

7.3 10.8 11.6 12.5 14.2 15.0 15.0 15.3 15.4 18.9 19.5 20.1 22.1 22.8 24.7 24.9 25.4 25.8 26.4 27.3 27.9 28.2

14.64 33.19 17.37 15.75 20.32 21.14 20.58 25.97 15.46 26.22 17.59 14.57 26.12 12.21 5.08 18.17 20.62 15.70 17.87 16.29 16.86 26.19

-14.2 -10.0 -14.2 -16.0 -16.0 -16.0 -14.2 -28.0 -16.0 -14.2 -14.2 -16.0 6.0 18.1 -16.0 -28.0 -16.0 -28.0 -28.0 -16.0 -28.0

89.0 78.0 82.0 39.0 66.0 87.6 44.0 78.0 87.5 87.5 49.8 87.5 210.1 87.5 35.0 87.5 87.5 75.7 87.5 78.0 82.0 210.1

27 31 38 12 35 23 22 39 17 13 6

28.9 30.2 31.7 32.3 32.8 33.7 33.9 35.2 36.1 44.3 70.6

19.48 -16.0 18.59 -28.0 23.86 -28.0 6.0 33.88 -7.0 28.18 11.92 -14.2 28.99 -28.0 -7.0 42.22 64.21 -14.2 20.00 -3.0 6.0 21.19

78.0 75.7 210.1 210.1 210.1 87.5 87.5 210.1 210.1 87.5 87.5

~28.0

max

ever, in most cases less clear than it was in the case of the water table. Examples from the both extremes of the gradient are shown in Fig. 11.

11. Bulk density of surface soil Although the parameter values range from 6 to 57 mg . cm- 3 the protozoan taxa show little differences in their distribution versus this factor (Table 11). Clearest difference between species might be that some species as Qua-

S.D.

7 27.4 4.82 5 27.8 5.48 3 28.1 0.85 10 28.6 6.89 31 28.8 6.82 26 28.9 15.86 17 29.4 12.81 32 29.6 9.17 33 30.4 12.10 26 31.1 17.80 13 32.8 13.30 42 33.2 14.55 44 34.7 15.35 19 35.1 15.29 10 36.5 17.03 32 37.2 15.8 36 37.3 18.02 47 38.2 18.73 36 38.4 15.13 26 38.7 10.87 60 40.7 15.12 28 41.3 19.03 10 45.4 12.67

min

max

7.9 8.4 9.9 15.4 9.5 8.4 9.5 10.2 8.4 8.4 9.9 4.5

48.9 55.6 27.3 28.7 51.4 51.4 51.4 40.5 58.8 40.5 33.4 62.1

8.4 58.8 4.5 62.1 9.7 55.2 13.1 19.0 27.6 13.6 4.5 7.9 13.1 9.7 9.7 4.5 9.9 4.5 4.5 9.7 9.7 9.7 4.5 4.5 7.9 11.8 4.5 4.5 4.5

35.4 38.6 29.8 49.2 55.2 62.1 62.1 55.2 62.1 58.8 62.1 58.8 62.1 58.8 57.6 62.1 62.1 62.1 62.1 62.1 62.1 62.1 55.6

drula symmetrica, Lesquereusia spiralis, Nebela langenijormis, N. carinata, Sphenoderia lenta and Amphitrema wrightianum were missing from dense samples. Except for Sphenoderia lenta, these species belong to the taxa of wettest moss carpets.

12. Depth of the samples As seen from the scattergram examples (Fig. 12) the depth of the sample analyzed, although always standardized

130

K . TOLONEN el al. AIceJ/a 81fOCIeIJ

CentropyIcJs ~

2000

750

1000

.. . ...

0

20

0

40

_

60

IIlI1g

r'

HeIeopeta syhtIca

200

•

••

20

40

• • e2]2 . . . .:ze

0

0

.

•

60

500

60

40

III

20

0

60

Ill·

40

60

...

•• • •• •

0

40

60

•

500

20

40

SpheIIOderla I8IItB

1000

..-

III

. . . . .2.

0

.

0

. .. . •. .•

•

••2

QuadnJIII~

600

2000

2

20

0

400

1000

321_2_

0

4000

•

.... ... .- .-

500 250

EugIypha tubet'cuIItf

1500

0

20

80

Fig. 8. Distribution of six testacean species (ind./cm 3 peat, y-axis) versus the dissolved organic cacbon (DOC) of water (mg C . 1- 1 x-axis) . See Fig. 2. Amphrltema fIavum

6000

7500

•

4000 2000 0

'20

600 400 200 0

'20

2_

0

••~l.

2500

• le._ 0

20

0

0

40

60 c..

Nebe/a car/nata

6000

1000

.. --

NebeJa miIiIBtIs

0

.2 •

20

40

60

'20

40

4000

. -

0

'20

60

..

J_ •0 0 2 • 2_ -z -2 l- 2 _ •

20

IIIIgUStIcoIIis

.-. . • -z- .... 02

0

00

20

0

2000

o ••

.

•

500

1 •••

oo oo •

.J225422212".J •

4000

.-... 0

' 20

~

1500

5000

-.

•

.

CenIropylds IJfCeIIoIdes

l

2 _ . ·2·2 2

20

0

40

60

40

60

Tr/gonopylds aICIIIa

2000

2·

0

40

60

' 20

-

-4

2_ .. _ JIll ·n

0

20

oo

••

Fig. 9. Distribution of five testacean species and the rotifer Habrotrocha angusticollis (ind./cm 3 peat, y-axis) versus the water table depth during sampling (cm below the mire surface, x-axis). See Fig. 2. immediately below the green moss carpet, had influence on the distribution pattern and abundance of many testacean species . Taxa that displayed negative correlation with depth (in their absolute numbers) included Difflugia bacillifera. Cyelopyxis areelloides-type, Heleopera sphagni. Nebela griseola. Plaeocista spinosa. and Nebela tineta. Species which increased with depth included Amphitrema wrightianum and Nebela marginata. Most species had more or less clear maximum between I em and 18 cm (the extreme sampling depths . Table 12), the clearest maximum values were seen for Hyalosphenia ovalis and H. papilio (at about 9 cm), Quadrula symmetriea (about 10 cm),

Phryganella acropodia (about 7 cm), Nebela militaris (about 6 cm), Arcella eatinus (about 9 cm), Assulina museorum and Centropyxis cassis-type (about 4 em), and Euglypha strigosa (about 12 em).

13. Fluctuation of the water table Although the calculated parameter does not give any real measure of the range of the water level fluctuation at the sampling sites, it does illustrate the relative difference between the sites in this respect during the snow free periods in 1982-1984 (i. e. in Lakkasuo data).

Ecology of Teslaceans

Table 9. Weighted averages (WA) of the water table (em) during sampling for different species with standard deviations (S.D.) and minimum and maximum values. n = number of observations. WA

Species

n

Amphitrema wrightianum Nebela carinata Lesquereusia spiralis DijJlugia leidyi Amphitrema flavum Placocista spinosa Heleopera petricola DijJlugia bacillifera Quadrula symmetrica Arcella rotundata var· aplanata Arcella discoides Hyalosphenia papilio Nebela marginata Centropyxis aculeata-type Hyalosphenia elegans Euglypha strigosa Hyalosphenia ovalis Habrotrocha angusticoLLis Heleopera sphagni Nebela griseola Assulina seminulum Bullinula indica Phryganella aeropodia Sphenoderia lenta Arcella catinus Corythium dubium-type Euglypha tuberculata Nebela militaris Nebela parvula Euglypha rotunda Arcella artocrea-type Heleopera sylvatica Assulina muscorum Centropyxis cassis-type Nebela lageniformis Trigonopyxis arcula Cyclopyxis arcelloides-type Nebela tincta

5 17 3 12 30 2 17 9 8 22

0.8 1.4 1.7 2.3 2.8 2.8 3.1 3.3 4.1 4.2

4 30

4.8 7.1 7.8 7.8 8.0 8.1 8.5 8.7 9.1 9.3 10.9 12.7 12.8 13.0 13.5 14.1 14.6 15.1 15.1 15.4 15.6 15.8 16.6 18.9 19.4 19.5 20.6 22.4

11

38 19 20 12 34 36 19 30 9 26 14 31 46 38 49 28 27 7 31 64 40 6 37 62 40

S.D. 1.56 5.20 3.78 5.62 6.03 9.98 6.74 5.64 4.40 6.20 7.14 6.81 7.30 4.90 6.445.15 7.13 8.61 7.18 8.19 7.57 8.57 8.15 6.92 7.94 6.64 13.59 5.33 5.51 12.00 1 \.62 5.78 11.16 12.60 7.37 6.88 17.35 15.71

min

max

-2.0 18.0 -10.0 15.0 '-2.5 -10.0 -4.0 -10.0 -2.0 1.0 -4.0

20.0 20.0 23.0 18.0 18.0 18.0 33.0

-2.0 -10.0 -2.0 -2.0 -4.0 -4.0 -10.0 -4.0 -4.0 -4.0 -2.5 -2.0 -2.0 2.0 -2.0 -4.0 -2.5 0.5 -2.5 -2.5 -2.0 0.5 -10.0 -2.0 1.0 0.2 -10.0 0.5

17.0 18.0 18.0 23.0 17.0 23.0 23.0 23.0 23.0 33.0 34.0 33.0 30.0 20.0 34.0 34.0 60.0 34.0 60.0 60.0 33.0 24.0 60.0 60.0 23.0 34.0 60.0 60.0

A general feature is that the mire water table fluctuates seasonally following the precipation much more closely on hummocks than in hollows (LINDHOLM & MARK KULA 1984). Accordingly, in the present material the mean figures were clearly lower in habitats of the taxa prefering higher moisture content (e.g. Amphitremaflavum, Heleopera petricola and Nebela carinata, only 1-2 cm), than at sites of species inhabiting drier hummocks (e.g. Euglypha tuberculata and Nebela tincta). Some species seemed to have little difference versus small or greater range of the water table (e.g. Arcella catinus,

131

Table 10. Weighted averages (WA) of the moisture content of peat (%) during sampling for different species. n = number of observations. Species

n

WA

S.D. min

max

Bullinula indica Nebela tincta Centropyxis cassis-type Cyclopyxis arcelloides-

10 40 42 68

80.9 83.2 83.6 84.1

5.18 8.81 8.64 9.22

77.8 70.2 70.2 68.3

97.1 98.0 98.4 99.2

Trigonopyxis arcula Assulina muscorum Nebela parvula Corythium dubium-type Arcella artocrea-type Sphenoderia lenta Nebela militaris Euglypha rotunda Euglypha tuberculata Heleopera sylvatica PhryganeLLa acropodia Arcella catinus Assulina seminulum Nebela griseola Arcella rotundata var. aplanata Heleopera sphagni Hyalosphenia ovalis Euglypha strigosa Hyalosphenia papilio Hyalosphenia elegans Nebela marginala Heleopera petricola Centropyxis aculeata-type Habrotrocha angusticollis Amphitrema flavum Lesquereusia spiralis Difflugia leidyi Difflugia bacillifera Nebela carinata Nebela lageniformis Arcella disco ides Quadrula symmetrica Amphitrema wrightianum Placocista spinosa

37 67 27 47 9 14 51 27 38 31 28 33 32 21 26

85.1 86.6 86.7 87.0 87.4 89.0 89.3 89.6 90.0 90.4 91.6 9\,7 92.2 92.7 93.9

6.67 7.51 7.11 6.49 9.11 7.70 4.91 7.21 7.91 4.69 5.80 4.23 5.75 4.37 5.09

75.7 68.3 76.7 68.3 77.8 78.9 75.7 70.2 68.3 75.7 76.7 75.7 75.7 78.8 78.8

98.4 99.2 97.1 98.4 97.1 97.1 98.0 98.4 98.4 98.4 98.0 98.4 99.2 98.4 99.2

94.1 94.5 94.8 95.1 95.3 95.5 95.6 95.6 95.6 96.0 5 96.2 15 96.3 10 96.4 19 96.6 5 96.7 6 96.7 8 97.0 7 97.6 4 97.8

4.23 3.47 3.19 2.31 2.23 1.19 3.26 \.63 3.11 2.17 0.97 2.65 0.93 1.24 1.04 1.82 1.74 1.01 0.61

78.8 76.7 76.7 91.3 91.5 88.7 86.1 86.8 76.7 81.1 94.0 78.8 95.0 91.3 95.6 91.8 94.5 95.0 94.4

98.4 97.9 99.2 98.0 97.9 97.1 98.4 99.2 98.4 99.2 97.1 98.4 97.9 98.4 98.4 98.0 98.4 98.4 97.9

type

Centropyxis

39 14 21 36 22 12 19 40 35 35

arceUoides-type,

Assulina

muscorum) ,

whereas most species had their peak abundance within a relative narrow range of the water table fluctuation, e.g. Amphitrema flavum, Assulina seminulum.

14. Presence of Sphagnum Three species, Amphitrema wrightianum, Arcella discoides and Hyalosphenia eiegans, were encountered only in habitats containing Sphagnum. Further, eight species

132

K. TOlONEN et al. . Amp/IIttem8 fIavum

1000

CenIropy.1ds srceIIoIdes

SDOO

SOD

.-..

0 -SO

0

1

un

0

lSO em

100

-SO

•

•

- ... •2

2000

SO

0

100

lSO

100

lSO

0

0

_22 ••

0

2

.

••

4000

....

2S00

SO

NebeIa mII/IBI1S

•

7SOD

-SO

SO

0

lSO

100

1SOD

1000 SOD

:

-.. 2-

o

.22-

-SO

o

SO

Fig. }O. Distribution of three testacean species and the rotifer Habrotrocha angusticollis (ind.lcm 3 peat, y-axis) versus the mean depth of water table calculated from weekly observations during three years preceding the sampling at Lakkasuo mire (cm below the mire surface, x-axis). See Fig. 2. CentropyxJs 8C/Ileata

2000

Centropyxls 81C8IIoides

•

7SOD

••

SDOO

.

1000

•

2500

2 1

•2

In

:zut:-

0 60

70

80

90

EUlllyph. tubercul.t.

•

1SOD

1000

. ...

....

SOD

• 2 •

0

100

2

60

70

80

2J·2.~

100

90

60

Phryg8ne/lll1ICI'OpOfJ;.

NebeJa tinct8

600D 400D

1000 0 60

70

. . ... 80

1000

.z •• • •

22 2. 2:nllJ

90

•

0

100

•

60

70

80

.- ..... 90

-

100

o 02 •

2

80

90

2

100

Trlgonopyxis ~

4000

SOD

10

..

.. • -----o•

2000

•• 0

60

70

80

... • . •

_)2_ 1. l "- 20200 90

100

Fig. 11. Distribution of six testacean species (ind.lcm 3 peat, y-axis) versus the moisture content of peat (% off. w., x-axis). See Fig. 2.

occurring in Sphagnum with a frequence over 90% included (in decreasing frequence order): Hyalosphenia papilio, Nebela griseola, Amphitrema flavum, Arcella catinus, Assulina seminulum, Hyalosphenia ovalis, Arcella roturuiata var. aplanata and Nebela marginata. Only four taxa : Euglypha rotunda, Quadrula symmetrica, Lesquereusia spiralis and Nebela Lage.niformis had the percentage presence of Sphagnum below 70%, the last mentioned species being the only one with a maximum occurrence in Bryales rather than Sphagnum (frequency of Sphagnum

<33 .3%).

Discussion This study has revealed some important ecological factors influencing the distribution of testaceans in mires in southern Finland .. It is difficult to assess the relative importance of these variables because there are so few studies on testacean ecology for comparison where the same ecological parameters were measured. One problem in our study has been precise taxonomic identification of testaceans because some genera such as Centropyxis or Euglypha are

Ecology of Teslaceans

Table 11. Weighted averages (WA) of the survace peat bulk density (mg· cm -3) for different species with standard deviations and minimum and maximum values. n = number of observations. Species

n

WA

QuOdrula symmetrica Amphitrema wrightianum Nebeln carinata Heleopera pelrieoln Nebeln marginala Euglypha strigosa Sphenoderia lenta Areelln ealinus Nebela lageniformis Heleopera sphagni HeJeopera sylva/ka Hyalosphenia elegans Nebela griseola Arcelln discoides Lesquereusia spiralis Arcella rOlundata var. aplanata Hyalosphenia ovalis Hyalosphenia papilio D.ifjlugia leidyi Habrotrocha anguslicollis Amphitrema flavum Assulina muscorum Difflugia bacillifera Phryganella aeropodia Nebela parvula Nebela militaris Centropyxis aculeata-type Cyciopyxis arcelloides-type Trigonopyxis arcula BulJinuJa indica Euglypha rotunda Centropyxis cassis-type EugJypha tuberculata Nebeln tincta Assulina seminulum Placocista spinosa Corylhium dubjum-type Arcella artocrea-type

8 7 19 19 12 21 14 33 5 39 31 22 21 6 5 26

13.7 9.38 6 .0 17.0 11 .70 8.0 R.O 17. 1 7.80 17.6 8.80 6.0 18 .6 9.22 12 .0 18 .6 6 .19 9.0 19.3 5.88 12.0 19.6 8.95 8.0 20.2 9.72 6.0 20.7 9.23 6.0 20.8 lO.30 6.0 21.1 7.67 10.0 21.2 8.06 8.0 21.4 12.41 11.0 22.4 7.40 12.0 22.6 7 .60 ' 8.0

14 22.7 36 22.9 15 22.9 35 23 . 1 35 23.2 67 23.4 10 23.6 28 23.7 27 24.1 51 24. 1 40 24.4 68 24.5 37 26.3 10 26.3 27 26.6 42 26.6 38 27 .5 40 28.4 32 28 .8 4 29.2 47 29.8 9 32 .0

S.D.

9.29 8.44 7.05 10.29 11.09 12.12 10.25 10.39 10.61 10.78 8.47 13.44 11.60 8.72 11.02 14.92 15.50 13 .88 11.74 10.07 16.90 8.95

min

10.0 10.0 8.0 6.0 8.0 6.0 12.0 9.0 9 .0 9.0 6.0 6.0 8.0 10.0 6.0 6.0 6.0 9.0 11.0 10.0 6.0 10.0

max 27.0 37.0 35.0 43.0 43 .0 54.0 33.0 54.0 33.0 57 .0 54.0 38.0 40.0 38.0 32.0 39. 1 54.0 40.0 38.0 57.0 45.0 57 .0 39.0 54.0 57.0 57 .0 43.0 57.0 45.0 45.0 57.0 57.0 57.0 54.0 54.0 38 .0 57.0 40.0

agglomerations of several species which are difficult to distinguish. In this discussion we will comment only on the taxa we are confident are single species. Most ecological classifications have simply categorized testacean habitats into xerophytic, hydrophytic, and hygrophytic , and whether they are associated with fen, bog hollow, or bog hummock. The most widely used classification is one developed by lUNG (1936) in Germany who related testaceans to soil moisture content on a scale of I to vrn. DE GRAAF (1956) and MEISTERFELD (1977) refined

I33

Table 12. Weighted averages (WA) of the sample depth (em) for different species with standard deviations (S.D.) and minimum and maximum values . n= number of observations. Species Lesquereusia lpiralis Placocista spinosa Bullinula indica Corylhium dubium-typc Assulina seminulum Cycfopyxis areelloidestype Centropyxis cassis-type Assulina muscorum Euglypha rotunda Nebela tineta Sphenoderia lenta Arcella artocrea-type Trigonopyxis arcu/a Eug/ypha tuberculata Nebe/a mililaris Nebe/a parvula Difflugia bacillifera Hefeopera sylvatica Habrotrocha angusticollis Hyalosphenia ovalis Hyalosphenia elegans Phryganella acropodia Arcefla rotundata var. aplanata Hyalosphenia papilio Amphitrema flavum C enlropyxis aculeata-type Nebela lageniformis Heleopera sphagni Arcella catinus Quadrula symmetrica Nebela grjseola Euglypha strigosa Difflugia leidyi Arcella discoides HeJeopera petricola Nebela carinata Nebela marginala Amphilrema wrightianum

n

WA

S.D. min

max

47 32 68

4 .2 4 .3 4 .6 4.6 4.7 4.8

3.14 3.54 2.01 3 .21 3.69 3.95

1.0 1.0 1.0 1.0 1.0 1.0

12.5 11.0 11.0 15.0 17.5 IR.O

42 67 27 40 14 9 37 38 51 27 10 31 35 14 22 28 26

5. 1 5.3 5.7 5.8 5.9 5.9 6.3 6.3 6.6 6.7 6.7 6.8 6.8 7.0 7. 1 7.3 7.5

3.21 1.0 3.25 1.0 3.39 1.0 3.47 1.2 4.63 1.0 3.58 1.0 2.89 1.0 4.38 1.0 3.14 1.0 3.78 1.0 4.08 2.0 2 9. 5 1.0 5.23 1.0 3.26 1.0 4.36 1.5 4.01 1.3 4.25 1.0

15.5 18.0 12.5 17.5 15.0 15.5 18.0 17.5 17.5 15.5 15.5 17.5 18.0 17.5 17.5 15.0 18.0

36 35 40 5 39 33 8 21 21 15 6 19 19 12 7

7.7 7.7 7.8 7.8 8.0 8. 1 8 .1 8.6 9.4 9.4 10. 1 10.2 10.2 10.8 14 .5

4.26 5 .87 4 .26 5.75 4 .24 3 .76 3 27 . 4.23 2.71 5.10 5.31 4.87 3 .96 4 .11 4.67

17.5 18.0 17.5 15.5 18.0 18 .0 12.5 18.0 15.5 18.0 15.0 18.0 18.0 15 .0 18.0

5 4 iO

1.3

1.0 1.0 1.0 2.0 1.5 1.0 4.0 1.0 1.5 1.5

1.0 2.5 2.0 3.0

the lestacean moisture. scale by placing more specific moisture figures. When comparing the testacean distributions in our study, we found them to include only representatives of classes II through VII because we did not sample the extreme dry and aquatic habitats at each end of the scale. Our weighted average technique recognized 5 moisturc categories, some of which are combinations according to lUNG'S scale. Bullinula indica and NebeLa tincta clearly fall on the xerophilous end of the scale being found in sites

134

K.

TOLONEI'!

et al.

AmphitTema wrIghtJanum

1000

• 500

..

0

0

..

5000 2500

• 10

5

15

lOl Z1 2'" )ol"2

5

20 em

20

10

2

200 100

15

20

• _z_ .. •

....

0 0

.... . • a

5

10

•

20

•

...• IS

.

a

•

4000

z

2000 02

0

0

20

0

5

10

10

15

20

15

20

NebeJa milltaris

6000

200

5

0

HyaJosphenia ovalls

400

. ..

•

0

a

2

a

1000

Dlftlugia bacillifenl

300

.. . ... . .. ... .

• ••

0

HyaJosphenia papl/lo

2000

..

Cenlropyxi8 aroelloldes

7500

U

0

a

. .·• .. • . te-.2 • • .2 Z

a

5

10

1

15

20

Fig. 12. Distribution of six testacean species (ind.lcm 3 , y-axis) versus the depth of sample below the peat surface (cm, x-axis). See Fig. 2.

with less than 85% moisture content. Earlier observations by SCHONBORN (1963) found B. indica to be more characteristic of drier sites, while SCHON BORN (1962) and MEISTERFELD (1977) found the optimal range for N. tincta in wetter sites. Arcella artocrea-type, Assulina muscorum, Nebela militaris, Sphenoderia lenta, and Trigonopyxis arcula fell into group 6, moisture content 85 to 90%. These species show similar moisture preferences as found elsewhere (TOLONEN 1986). Our third group, Arcella eatinus, Areefla rotunda var. aplanata, Assulina seminulum, Heleopera sylvatiea, H. sphagni, Hyalosphenia ovalis, H. sylvatiea, and Nebela griseola, comprise our hygrophilous group, moisture content between 90 to 95 % in moisture class 5. There is a wide range in moisture preferences, asA. eatinus, A. seminulum, H. ova/is, and N. griseola have been reported on somewhat wetter sites (DE GRAAF 1956; TOLONEN 1966, 1967), and Heleopera sylvatiea, H. sphagni, and A. seminulum have been found in drier habitats (HEAL 1%2).;1. rotundata var. aplanata coincides with other observations. Our fourth group corresponds to moisture class IV with about 95% water content. The species include Heleopera petrieola, Hyalosphenia elegans, H. papilio, Nebela marginata, and the rotifer Habrotrocha angusticollis. Most of these species are found in similar moisture regimes as reported by other researchers, with the exception of H. papilio which is more typical of wetter sites (SCHONBORM 1962; MEISTERFELD 1977). The rotifer is most often regarded as a species of bog hollows of Phragmites peat in wetter sites (STEINECKE 1927; JUNG 1936; TOLONEN 1966). Our last group falls within moisture class n - III in peat with

more than 95 % water content. Amphitrema jlavum, A. wrightianum, Arcella diseoides, DiJflugia bacillifera, D. leidyi, Lesquereusia spiralis, Nebela earinata, N. lageniformis, Plaeocista spinosa, and Quadrula symmetrica are all species typically found in this moisture category (SCHONBORN 1962; MEISTERFELD 1977). A. jlavum has been found in drier sites in bog hummocks in England (HEAL 1962). The importance of the trophic status of sites was revealed by distributions of certain species. Most of the species recorded in our study were found to occupy the whole range of trophic levels represented in our study, peak abundances were often found to be typical of sites of only one or two trophic levels. Lesquereusia spiralis was not recorded in any ombrotrophic sites, suggesting that is prefers the wettest and more minertrophic sites. BERZINS & STENSDOTTER (1989) found a similar pattern for L. spiralis in Sweden. On the other extreme, a more restricted distribution was characteristic for Arcella diseoides, Bullinula indica, and Heleopera sylvatica. These three species do not appear in nutrient-rich eutrophic sites. B. indica, a species of dry ombrotrophic bog hummocks in our study and that by HEAL (1962), has also been found in terrestrial forest soils (BONNETT & THOMAS 1955; GROSPIETSCH 1953; SCHONBORN 1962). HeJeopera sylvatiea is interesting because GROSPIETSCH (1953) reports it to be characteristic of dry bog habitats in artificially drained sites. We found it in only one sample which was from a drained site. Several testaceans previously considered as bog species were found to be widely distributed in minerotrophic and mesotrophic sites with greater than 5.5 pH. Such species include Amphitrema jlavum, A. wrightianum, A. artocrea-

Ecology of Testaceans

type, Hyalosphenia ovalis, and Nebela carinata. Therefore it seems that certain testaceans may not be as narrow in their habitat preferences as previously thought. The strong relationship between testate amoebae and depth of the moss samples used for testate amoebae analyses further reflects the importance of site moisture conditions. Those species showing no association with sample depth are probably indifferent to moisture or were present in so few numbers, no clear correspondence could emerge. It is difficult to explain species association with the extent of Sphagnum cover. In this case, it may be more appropriate to determine ecological factors controlling Sphagnum distributions first, before superimposing ecological factors associated with testate amoebae distributions. Clearly, it is difficult to identify precise environmental variables controlling testacean distributions because many of the environmental variables are interrelated. One or any combination of factors may be important. We will consider the environmental interrelationships affecting testacean distributions in southern Finnish mires in a subsequent paper (TOLONEN et a1. 1993).

Acknowledgements We appreciate the assistance of Dr. LAURI ARVOLA and MEIUA LEHMUSVUORI, M. Sc., of the Lammi Biological Station for providing chemical analysis, Dr. PERTTI HUTIUNEN for assisting with statistical analyses, Ms. TARJA TIKKANEN, University of loensuu and Ms. PrRKKO DOOKIE for technical assistance in preparing the manuscript. The Lammi Biological Station kindly provided research facilities. B. G. WARNER gratefully acknowledges the financial support of the Finnish Ministry of Education and the Natural Sciences and Engineering Research Council of Canada.

135

A. rotundata var. aplanata. As in GROSPIETSCH (1958). Test characterized by thickening around mouth. Includes all varieties of this species. Centropyxis aculeata-type. Tests are bilaterally symmetrical with obvious posterior spines. May include C. hirsuta and C. spinosa. C. cassis-type. These tests are bilaterally symmetrical with no proximal spines. May include C. aerophila-type and varieties, C. constricta, and C. platystoma. Cyclopyxis arcelloides-type. Tests are bilaterally symmetrical, hemispherical in shape with large circular mouth. Test usually covered with siliceous and other mineral particles. May include C. eurystoma. Corythion dubium-type. See TOLONEN 1986. May include Trinema lineare and T. enchelys. Euglypha strigosa-type. Includes all Euglypha tests with spines. Size usually greater than 4O!lm in length. May include E. acanthophora, E. compressa, and E. ciliata. E. tuberculata. Tests greater than 40 IJ.Il1 without spines. E. rotunda. Tests usually less than 30!lm without spines. Hyalosphenia papilio. Test with gradually tarpering walls when viewed in cross-section as opposed to H. ovalis where test walls are somewhat constricted midway. Includes all forms of H. papilio with 2 to 4 lateral pores. Phryganella acropodia. TOLONEN (l986) notes that differentation between P. acropodia and C. arcelloides-type is difficult. In this study tests of P. acropodia were considered to be those composed of organic detritus and fungal hyphae. Heleopera pelricola. As in CORBET (l973). Untidy test with numerous mineral particles. Lips thickened, meeting side walls at rounded angle. Generally in Ienght. H. rosea is similar but is recognized on the basis of wide-red and organe yellow colour. We did not find colour to be a reliable diagnostic aid in our study, hence, H. petricola may include H. rosea.

Appendix 2 Appendix 1 Notes on testacean identifications. In our material, it was difficult to consistently distinguish certain taxa. The following groups were erected, though in many instances all species were represented. Arcella artocrea-type. As in GROSPIETSCH (1958). Tests are round in dorsal/ventral view and bowl-shaped in side view. Convex surface is irregular with numerous bulges. Mouth usually not recurved in side-view. Tests are large, usually greater than 150 !lm. May include A. gibbosa. A. catinus. As in CORBET (1973). Tests are irregular and noncircular in ventral/dorsal view, with obvious ring of pores (ca. 12-25) around mouth. A. discoides. Distinctly circular in outline, saucer-shaped or flatter in shape. Test wall thin with no obvious thickening around mouth. May include A. megastoma and A. polypora of GROSPIETSCH (1958).

Description to the sampling sites in October 1984 1. Central plain in the NE comer of an eccentric raised bog Kaurastensuo, Lammi (see TOLoNEN 1987). About 40 cm high Sphagnum fuscum hummock with Empetrum nigrum. Ombrotrophic. 2. Ditto, about 20 cm high only 2 m, away. Ombrotrophie. 3. Ditto, about 40 cm high. Ombrotrophic. 4. Ditto, about 35 cm high. Ombrotrophic. 5. About 100 m SW from site 1. Wide Eriophorum vaginatum - Scheuchzeria palustris hollow with Sphagnum balticum (domin.) and S. tenellum. Ombrotrophic. 6. Ditto, Sphagnum tene/lum - S. balticum. Ombrotrophic. 7. Extensive mire complex Suurisuo, lanakkala (see RuuHIJARVI 1979; LINDHOLM & VASANDER 1990). Carex diandra flark fen with Scorpidium scorpioides. Eutrophic.

136

K . TOLONEN et aI.

8. Ditto: Cinclidium stygium . Eutrophic. 9. Ditto: Sphagnum teres and S. obtusum. Eutrophic. 10. The same mire, Eriophorum vaginatum - Carex lasiocarpa - fen with continuous Sphagnum papillosum. Oligo-minerotrophic. II. The same mire, sedge fen with Phragmites australis and Sphagnum subsecundum. Mesotrophic. 12. The same mire. small hollows with cotton grass. Scheuchzeria palustris and Sphagnum jensenii. Ombrotrophic. 13. Ditto, Carex limosa, C. chordorrhiza and Sphagnum lindbergii. Oligo-minerotrophic. 14. As above with c.g. Utricularia intermedia and Sphagnum obtusum. Meso-minerotrophic. 15. Kaurastensuo, Lammi (cf. site I) . Central plain: isodiametric Scheuchzeria-depression with Sphagnum majus (and some S. balticum). Ombrotrophic. 16. Ditto, the northern marginal scarp. High hummock with Dicranum bergeri. Ombrotrophic. 17. Ditto: Cladina rangiferina - surface. Ombrotrophic. 18. Ditto: C. arbuscula - surface. Ombrotrophic. 19. Ditto : Pleurozium schreberi - surface (with some Sphagnum angustifolium). 20. Suurisuo mire, Turenki (see site 7). Pine bog area in the southern part of the complex. Eriophorum Sphagnum rubellum lawn level. Ombrotrophic. ·21. As above, southern lagg-area with birch, alder and spruce plus sedges. Sphagnum riparium - depression . Oligotrophic. 22. Ditto: Sphagnum centrale. Meso-minerotrophic. 23 . Ditto: Sphagnum warnstorfii. Eutrophic. 24. Lakkasuo mire. Orivesi, an eccentric raised bog with various ground water fed vegetation in the lagg-areas (LAINE et al. 1986). Vaccinium myrtillus - spruce forest: ground layer vegetation almost lacking. Samples from litter ± humus. Oligominerotrophic. 25. Ditto: litter. Oligo-minerotrophic. 26. Ditto: slightly paludified. PoLytrichum commune. Oligominerotrophic. 27. Ditto, lagg zone with birch, spruce, pine, Equisetum si{vaticum, Sphagnum magellanicum (domin .), S. angustifolium and S. girgensohnii. Oligo-minerotrophic . 28. Ditto, with Sphagnum centrale, S. angustifolium and S. mageLianicum. Oligo-minerotrophic. 29. Ditto, with e.g. Potentilla palustris, Equisetum fluviatile, Eriophorum angustifolium and Sphagnum riparium. Meso-minerotrophic. 30. Ditto, with Sphagnum wulfianum, S. riparium and S. warnstorfii. Mcso-minerotrophic. 31. Ditto, with e.g. Agrostis canina, Sphagnum angustifolium and S. magellanicum. Meso-minerotrophic. 32. Ditto, cotton grass - sedge fen with Sphagnum angustifolium . Oligo-minerotrophic. 33. Ditto, sedge fen with Carex lasiocarpa, Sphagnum faLlax and S. papillosum. Oligo-minerotrophic. 34. Ditto, wet sedge fen with Menyanthes f1arks, other herbs and plenty of Equisetum fluviatile and Sphagnum platyphyllum. Meso-minerotrophic. 35. Ditto, Sphagnum subnitens. Meso-minerotrophic.

36. Ditto, Utricularia intermedia. Litter ± humus. Mesominerotrophic. 37. Ditto, pine swamp with Carex lasiocarpa (domin.), C. canescens and C. echinata. Sphagnum fallax. Oligominerotrophic. 38. Ditto, pine swamp with Carex rostrata and Sphagnum fallax. Oligo-minerotrophic. 39. Ditto, ditched pine swamp with cotton grass, Carex lasiocarpa and Sphagnum angustifolium. Oligo-minerotrophic. 40. As above, a hummock-level with Aulacomnium palustre. OJigominerotrophic. 41. As above with Dicranum sp. Oligo-minerotrophic. 42. Lakkasuo, Carex diandra sedge fen with plenty of herbs, Drepanocladus procerus. Meso-eutrophic. 43. A lake shore fen. Ala-HyytiiiHi, Kuivajiirvi, Juupajoki. Plenty of sedges and herbs. Paludella squarrosa. Eutrophic. 44. Ditto, Campylium slel/alum. Eutrophic. 45. Lakkasuo mire (see site 24), western part, Spruce swamp with Sphagnum girgensohnii (domin.) and S. angustifolium. Oligominerotrophic. 46. Ditto, and intermediate (moisture) level with Sphagnum magellanicum, S. centrale, Pleurozium schreberi and Rhytidiadelphus triquetrus. Oligo-minerotrophic. 47. Ditto, PLeurozium schreberi hummock. Oligominerotrophic. 48. Lakkasuo mire, spurce-pine mire, Sphagnum nemoreum - hummock. Oligo-minerotrophic. 49. Ditto, dwarf shrub pine bog (VIR) . Sphagnum russowii. Ombrotrophic. 50. Ditto, Sphagnum magellanicum, S. nemoreum and S. russowii. 51. Ditto, cotton grass pine bog with Sphagnum angustifolium , S. nemoreum and S. fuscum. Ombrotrophic. 52. Ditto, pine bog rich in cotton grass. tall dwarf shrubs and Sphagnum fuscum. Samples from Pleurozium schreberi surface. Ombrotrophic. 53. Ditto, Sphagnum juscum pine bog. Cetraria islandica, CLadina arbuscula, C. rangiferina surface. Ombrotrophic . 54. Ditto, very high Sphagnum fuscum hummock. Ombrotrophic. 55. Ditto, low S. fuscum hummock. Ombrotrophic. 56. Ditto, Rubus chamaemorus - Sphagnum angustifolium surface. Ombrotrophic. 57. Ditto, cotton grass - sedge fen with Carex rostrata (scattered individuals): Sphagnum angustifolium. Oligo-minerotrophic. 58. Ditto, Carex iasiocarpa, S. angustifolium. Oligominerotrophic. 59. Lakkasuo, southern part, eccentric kermi ridge hollow complex. Scheuchzeria - Sphagnum majus depression (15 x 5 m) . Ombrotrophic. (5 X 2 m) . 60. Ditto, Sphagnum cuspidatum-hollow Ombrotrophic. 61. Ditto, Sphagnum baLticum-hollow. Ombrotrophic. 62. Ditto, Sphagnum cuspidatum-hollow . Ombrotrophic. 63. Ditto, alder-birch swamp with plenty of herbs, grasses and sedges. Sphagnum warnstorfii. Eutrophic.

Ecology of Testaceans

64. Ditto, Pseudobryum cinclidioides. Eutrophic. 65. Ditto, Spl'Ulgnum centrale. Meso-minerotrophic. 66. Ditto, Carex lasiocarpa, Drepanocladus exannuLatus. Oligo-minerotrophic. 67. Ditto, Carex dioica hummock with Spl'Ulgnum fuscum. Meso-minerotrophic. 68. Ditto, Carex lasiocarpa, C. dioica, Sphagnum warnstorfii, S. subsecundum. Meso-minerotrophic. 69. Ditto, sedge, fen patches: Carex lasiocarpa, Calliergon stramineum, Drepanocladus exannulatus. Oligo-minerotrophic. 70. Lakkasuo, spring with Drepanocladus eJ{annularus. Oligo-minerotrophic. 71. Lake shore fen, rich in herbs and sedges, Lake Kuivajarvi, Ala-Hyytililli, Juupajoki, Drepanocladus intermedius. Eutrophic. 72. Ditto, meadow like sedge fen: Climacium dendroides. Eutrophic. 73. Ditto, hummock with Potemilla erecta, Juniperus, Carex dioica, Trichophorum alpinum and Sphagnum fuscum surrounded by e.g. Campylium stellatum. Eutrophic. 74. Lakkasuo mire (see site 24). Vaccinium myrtillus spruce forest. Plagiochila asplenoides. Rhytidiadelphus triquetrus ± bare litter and humus. Oligo-minerotrophic. 75. Ditto, spruce mire with thin peat. Sphagnum girgensohnii and Polytrichum commune. Oligo-minerotrophic. 76. Ditto, Carex glohularis spruce mire with thin peat. , Spl'Ulgnum angustifolium. Oligo-minerotrophic. 77. Laaviosuo mire, an eccentric raised bog (TOLONEN 1987), western bog plain, Cotton grass - Sphagnum balticum (± S. majus) hollow. Ombrotrophic. 78. Ditto, a high Sphagnum fuscum hummock. Ombrotrophic. 79. Ditto, ditched kermi peat ridge - hollow complex. Spl'Ulgnum majus. Ombrotrophic. 80. Ditto, Sphagnum balticum. Ombrotrophic. 81. Ditto, drained and treated with NPK fertilizers (see VASANDER 1982). Sphagnum balticum hollow. Ombrotrophic. 82. Heinisuo mire. Koski HI. (see REINIKAINEN et al. 1984). Birch swamp vegetation with Sphagnum fimbriatum. Oligo-minerotrophic. 83. Ditto, cotton grass pine bog with Sphagnum magellanicum and S. angustifolium. Ombrotrophic. 84. Ditto, a soak with sedges, herbs and Spl'Ulgnum warnstorfii. Meso-minerotrop~ic. 85. Ditto, Sphagnum flexuosum (plus some S. teres and S. angustifolium). Meso-minerotropbic. 86. Ditto, Spl'Ulgnum subfulvum (plus S. riparium). Oligominerotrophic. 87. Suurisuo mire, Turenki (see site 7). Carex chordorrhiza fen with Depranocladus revolvens. Eutrophic. 88. Lake Kuivajarvi, Juupajoki. Shore fen with Tomentypnum nitens. Eutrophic. 89. Heinisuo mire, Lammi (see site 82), Sphagnum annuicltum (cf. FLATBERG 1988). Oligo-minerotrophic. 90. Ditto, Sphagnum subfulvum. Oligo-minerotrophic.

137

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Authors' addresses: KiMMO TOLONEN, Department of Biology, University of Joensuu, P. O. Box 111. SF-8010l Joensuu, Finland; BARRY G. WARNER, Department of Geography, University of Waterloo, Waterloo, Ontario Canada N2L 3G 1; HARRI V ASANDER, Department of Peatland Forestry, University of Helsinki, Unioninkatu 4OB, SF-OOI70 Helsinki, Finland.