4.1. COMPUTER PROCESSING
4.1.1. Relevee clustering
The results of the clusterings were expressed in dendrograms. The clustering starts from the level of the individual relevees. On the vertical axis of the dendrogram the degree of similarity between clusters can be read. When comparing, the 'octave' and the 'binary' dendrograms showed resemblance above a certain level of branching. This level appeared to be the level above which the information was useful for this investigation. Finally, 12 clusters were distinguished (fig. 2), corresponding with the results of the hierarchic binary clustering and each representing a certain combination of species (table 8, 9 ). A survey of the desmid relevees can be seen in table 13.
Clustering (octave) with RELOCATE showed most agreement with the hierarchic octave clustering, which was to be expected, as the scale used and the method of calculation of the similarities was the same (Ward's method). In fact the results of these three methods of clustering affirm each other. None is perfect, but they complete each other. Together they make it possible to distinguish the final clusters.
4.1.2. Species clustering
The binary clustering of the species gave best interpretable results. For example, all (known) oligotraphent species were put together, whereas in the 'octave dendrogram' they could be found all over the dendrogram. In the survey of the clustered species (table 8), the species sequence is best reflecting the sequence of the binary clustering, although some modifications are made.
4.1.3. Macrophyte relevee clustering
The resulting dendrograms of the clusterings of the vegetation relevees were hard to interprate, not matching at all the algal dendrograms. A probable reason for this is the species poorness of the vegetation types (cf. Buys 1986).
4.2. CHEMICAL ANALYSES
For the results of the chemical analyses I refer to table 10. The results of the statistical analyses can be seen in the tables 4 and 5. In general it can be said that we deal with typical oceanic bogs, as can be seen by the relatively high Cl- and Na+‑contents. The NaCl content can be compared with that of the oceanic bogs of the British isles (Moore & Bellamy 1974). Also pH and conductivity of the oligotrophic waters of the area investigated, show higher values than those of continental bogs (cf. Sjörs, 1950b and Persson, 1962). The chemical analyses of the sampling sites will be discussed further on, in combination with the clusters.
4.3. ADDITIONAL DATA
Additional information about the sampling site, such as visible presence of iron, presence of waterflow etc. is noted in table 12 and will be discussed in combination with the clusters.
4.4. THE DESMID RELEVEE CLUSTERS
As stated before, I finally decided, on the basis of the several clustering results, to class the algal relevees into 12 ecologically relevant clusters (assemblies). Each cluster represents a certain combination of algal species, differing from other clusters. This difference in species composition can be correlated with ecological conditions.
In the clusters I distinguish 'constant species' ,i.e. species occurring in 40% or more of the samples belonging to a cluster. The threshold of 40% is arbitrary, in this case I follow Coesel (1981). An overview of these constant species is given in table 8. When discussing the clusters, species mentioned are constant species, if not, this is indicated. 'Unique species' are constant species limited to one cluster. The mutual relationships of the clusters are visible in the dendrogram (fig.2). The 12 clusters have been put into 5 groups. Group 1, 2 and 5 form the left branch of the dendrogram. In general these groups consist of clusters relatively poor in species (see table 8). When comparing with the other branch, this left branch is associated with (for desmids) more extreme environments with nutrient poorness, high pH and high nutrient contents or drought. The other branch, consisting of the groups C and D, represents clusters rich in species, combined with ecologically more optimal conditions for desmids. The sequence of the clusters in fig.2 is so that the most resembling clusters are put next to each other. An exception to this are the clusters 5‑A and 5‑B. Because of their low number of species the clustering program puts them in the left branch of the dendrogram. However, their species composition is more in agreement with cluster 4‑C, which they should join in the sequence 4-B > 4‑C > 5‑A > 5‑B. Below I will discuss the groups, and the clusters belonging to them, in the sequence just mentioned. Samples token in different substrates of a sampling site appeared, in most cases, to group in the same cluster (cf. Peterfi, 1974).
Linked to the clusters are macrophytic vegetation and chemical analyses. A survey of the macrophytic vegetation can be seen in table 6 (vegetation types), table 7 (most important macrophytes) and table 11 (vegetation of the sampling sites). The 'chemical analyses of the clusters' is shown in table 4 and 5, the chemical analyses of the sampling sites can be seen in table 10. When studying the chemistry especially the following parameters are discriminating the desmid assemblies; pH, conductivity, alkality, chloride and the cations of calcium, magnesium, sodium and potassium. Sulfate is just of interest in discriminating the higher trophic levels. The iron ions and the anions of phosphorus and nitrogen seem to be indifferent with respect to the clusters distinguished. In the following text only statistically significant parameters will be mentioned (table 5). When using the term Ca2+ ‑content or any other ionic content, the average ionic‑content of that group or cluster is meant. When pH‑values and conductivities of clusters or groups are mentioned, also the average values are meant.
4.4.2. Group 1
This group comprises the clusters 1‑A, 1‑B and 1‑C. These clusters represent the habitats with the lowest trophic states. pH, conductivities and ionic contents show the lowest values in this group. Dominant vegetations are the Sphagnum majus‑S. lindbergii community and the Gymnocolea‑Carex limosa community. These oligotrophic vegetation types are poor in species. Sphagnum majus and Drepanocladus schulzei are restricted to group 1. The clusters are poor in desmid species. Species that are common in other groups, lack here: Euastrum ansatum ,E. elegans, E. pectinatum and Cosmarium difficile.
There are hardly differences in the chemistry of the clusters 1‑A, 1‑B and 1‑C. The SO42- ‑ and N.NO3‑contents of cluster 1‑B are higher than those of cluster 1‑C, but with low significance. pH‑ values, conductivities, alkalinity and Cl- , Ca2+ , Mg2+ , Na+ and K+ ‑contents are low in all clusters.
The vegetation of the clusters 1‑A and 1‑B is roughly the same. Most sampling sites are representatives of the Sphagnum majus‑ S. lindbergii ‑ and the Gymnocolia‑ Carex limosa community, both representing oligotrophic wet hollow and pool vegetation. The first community occurs as floating mats in smaller deep pools or as carpets on the wettest sites. The second community develops in wet hollows or mudflats with a strongly fluctuating waterlevel. In both clusters Sphagnum tenellum , S.compactum and Scirpus cespitosus occur. These species prefer relatively dry sites (Eurola, Hicks & Kaakinen, 1984). Compared to cluster 1‑A, the vegetation of 1‑B indicates wetter conditions, as the Cyperaceae (flark indicating species) are present more frequently in 1‑B. In addition to the clusters 1‑A and 1‑B, Menyanthes trifoliata , a wet growing species, occurs in cluster 1‑C. The vegetation of this cluster represents mossless pool or lake vegetations or belongs to the Sphagnum majus‑ S. lindbergii community. Mossless lake vegetations occur on exposed sites like the shores of lakes.
As indicated by the vegetation, the moisture of the sampling sites belonging to theclusters seems to be an important discriminating factor. The moisture, in this case linked with the volume of the waterbody, will be of importance, as larger waterbodies have more ecological niches (planktonic species), a better nutrient supply (Tolonen & Hosiaisluoma 1978) and are less sensitive to drought (Eurola, Hicks & Kaakinen, 1984). Indeed, cluster 1‑A comprises a number of shallow moss‑grown pools of a few square metres, cluster 1‑B comprises also shallow pools but often with a considerably larger surface , and 1‑C represents even larger pools, small lakes in fact, which are generally deeper (see table 12). In cluster 1‑A and 1‑B also atmophytic conditions will occur due to emergent Sphagnum plants and/or a fluctuating waterlevel.
‑ Cluster 1‑A contains just 12 constant species (see table 8). Species characterized by cell extremities (planktonic species) are absent. Cosmarium obliquum just occurs in the clusters 1‑A and 1‑B. This species indicates atmophytic conditions (Krieger & Gerloff, 1969 and Symoens, 1957). Unique species do not occur here, it can be considered as a reduction flora of 1‑B and 1‑C.
‑ Cluster 1‑B contains 17 constant species. Cosmarium exiguum, Netrium oblongum and Tetmemorus brebissonii just occur in this cluster. Within group 1 Staurastrum simonyi and Tetmemorus laevis just occur in cluster 1‑B. Staurastrum avicula, though not a constant species, is present more often in 1‑B than in any of the other clusters.
‑ Cluster 1‑C contains 23 constant species. Cosmarium sphaeroideum, C. nymannianum, Euastrum insulare v . silesiacum , Staurastrum cingulum and Arthrodesmus octocornis just occur in 1‑C. Closterium tumidum and Spondylosium pulchellum show a preference for this cluster but are not constant species. More species with extensions are occurring here: Xanthidium armatum, X.smithii, Staurastrum cingulum , indicating an environment with deeper water. Also larger and flattened forms (sensitive to drought) like Cosmarium nymannianum, Micrasterias truncata and Euastrum ampullaceum occur in this environment.
4.4.3. Group 2
Chemistry, vegetation and desmid species composition indicate an intermediate position of group 2 between the oligotrophic group 1 and the mesotrophic groups.
As can be seen in the dendrogram (fig.2), the species composition of group 2 is closely related to that of group 1. When looking at the chemical analyses (table 4) the clusters of these groups show a lower pH and conductivity and lower Cl , Mg2+ ‑ and Na+ ‑contents than all other clusters. Likewise the vegetation, where Sphagnum lindbergii is a dominant species, indicates low trophic levels. In the desmid species composition this level is reflected in the absence of species that are common in the other 'richer' groups, like Cosmarium difficile v.constrictum, C.quadratum, C. margaritiferum, Closterium calosporum, Eastrum bidentatum. Two species are confined to group 1 and group 2: Actinotaenium silvae‑nigrae and Staurodesmus incus .
When comparing with group 1, group 2 (cluster 2‑A) appears to be much sricher in desmid‑species, many of which do not occur in group 1. The oligo‑mesotrophic Drepanocladus procerus ‑ Sphagnum lindbergii community, lacking in group 1, is the most important type of macrophytic vegetation. There are also macrophytic relations with the mesotrophic groups 3 and 4. Group 2 takes an intermediate position between these oligotrophic and mesotrophic groups.
When looking at the chemical analyses (table 4, 5) the clusters of the groups 1 and 2 show a lower pH and conductivity and a lower Cl , Mg2+ ‑ and Na+ ‑content than all other clusters. The trophic status of group 2 is higher than that of group 1, reflected by a higher pH and Ca2+ content.
Sphagnum lindbergii is a representative of the oligotrophic environment and shows a preference for the groups 1 and 2 (table 7). Carex lasiocarpa , C.livida and Drepanocladus procerus have a mesotrophic preference and can be found in group 2 and in the mesotrophic groups. Interesting is the occurrence of Sphagnum annulatum which is almost confined to group 2. The vegetation of most sampling sites belongs to the Drepanocladus procerus‑Sphagnum lindbergii community, which is described as oligo‑mesotrophic wet flark vegetation and shows a preference for this group. The variation within this community can be explained partly by a gradient along the trophic level. Sphagnum annulatum dominates the lower trophic levels.
When comparing with group 1, group 2 (cluster 2‑A) appears to be much richer in desmid‑species, many of which do not occur in group 1 and are in common with mesotrophic clusters. There are 35 constant species. Representatives of oligotrophic environments are: Euastrum ampullaceumm, Xanthidium smithiii, Actinotaenium silvae‑nigraee, Micrasterias truncataa, Staurodesmus incus. Mesotrophic species: Euastrum ansatum, E.elegans, E.pectinatum, Tetmemorus granulatus, Cosmarium difficilee, C.blyttiii, C.pseudopyramidatum and many more. Some species are confined to this group: Staurastrum brachiatum, Euastrum cuneatum and Sphaerozosma granulatum. Closterium nilssonii is a non‑constant species with a strong preference for this group
4.4.4. Group 3
Together with group 4, this group forms the right branch of the dendrogram, which is characterized by oligo‑meso to meso‑eutrophic conditions, desmid‑species richness, higher pH‑values and ionic contents, and a different vegetation. As a group on the whole, the chemistry of group 3 indicates a lower trophic status than group 4 (compare pH‑values, Mg2+ ‑, Na+ ‑ and K+ ‑contents). However there is a large overlap, due to the variation among the clusters within each group. Still the chemical analyses of each separate cluster in group 3 differs from that of each cluster in group 4. The overlap between the groups is caused by cluster 3‑C, which will be discussed below. Allmost all sampling sites of group 3 represent vegetations of (very) shallow waters. The water table is instable (moving), due to swamp influence as is indicated by the vegetation: the Calliergon sarmentosum‑Drepanocladus purpurascens community, the Sphagnum subsecundum‑Drepanocladus purpurascens community and the Carex chordorrhiza community are the prevailing vegetation types. Also a (periodically) strong water run‑off (indicated by the Juncus alpinus community) can be responsible for instability. Characteristic 'shallow‑water species' are for example Cinclidium stigium, Andromeda polifolia , Carex livida and Drosera anglica. 'Swampy species' are Drepanocladus purpurascens, Comarum palustre, Calliergon sarmentosum, Carex chordorrhiza and Equisetum fluviatile.
Most constant desmid‑species of group 3 are also present in group 4. Closterium calosporum , Cosmarium tinctum , C. subundulatum, Euastrum bidentatum and Staurastrum teliferum occur in (and are almost confined to) all clusters of these groups. The clusters of group 3 have no species in common that are not present in group 4. Like with the chemical analyses it is necessary to consider each cluster apart. A common feature is that the desmid composition of each cluster of group 3 combines a (different) part of the constant species of group 4. A number of desmid species are limited to one or two clusters of group 3.
Cluster 3‑A and 3‑B do not differ significantly. Cluster 3‑C shows higher conductivities and Ca2+ ‑ and Na+ ‑contents than both clusters. Remarkable is the presence of a relatively high content of iron in cluster 3‑C. The chemistry of 3‑C causes the overlap of this group with group 4. Cluster 3‑C shows a higher Cl and Fe‑ content than this group.
Many species occur in all clusters of this group. Carex livida, Andromeda polifolia, Drosera anglica, Comarum palustre, Scorpidium scorpioides, Drepanocladus revolvens, D.purpurascens and Calliergon sarmentosum are often present together in many of the relevees of the clusters. This combination does not occur in the clusters of the other groups. As mentioned above, it is typical for shallow mesotrophic ( and meso‑eutrophic ) swampy waters. Like the chemical analyses, the vegetations of cluster 3‑A and 3‑B show no striking differences. The different 'swampy vegetation types' occur in both clusters. Scirpus caespitosus occurs more frequent in cluster 3‑A, whereas Pedicularis palustris is present more frequently in 3‑B. Most samples of cluster 3‑C are token in the Carex chordorrhiza community . Campylium stellatum, Calliergon richardsonii and Sphagnum teres just occur in 3‑C (the latter two are entirely confined to this cluster).
‑ Cluster 3‑A: 30 constant species. This cluster shows the lowest degree of trophy within this group. The oligotrophic Cosmarium amoenum and C. sphagnicolum occur here, while mesotrophic species like Closterium cynthia , C.gracile, Penium cylindrus, Cosmarium pyramidatum and C.punctulatum lack. C. laeve var. messikommeri and Staurastrum punctulatum are limited to this cluster. Typical mesotrophic species like Micrasterias thomasiana, M. rotata, Cosmarium rectangulare var. croasdaleae, C.perforatum and C. tuddalense do not occur in this cluster
‑ Cluster 3‑B: 47 constant species. The mesotrophic species mentioned above are present here. Species limited to this cluster: Cosmarium globosum , Euastrum binale v. binale and E. insulare. Closterium intermedium and Micrasterias thomasiana just occur in cluster 3‑B and 3‑C.
‑ Cluster 3‑C: 58 constant species. A lot of species are present as constant species just in this cluster: Micrasterias rotata, Closterium incurvum, C.rostratum, C.angustatum, C.venus, Cosmarium tuddalense, C.perforatum and Staurastrum trapezicum and more. There are clear relations to the meso‑eu trophic clusters 5‑A and 5‑B. Species in common are: Closterium parvulum, Cosmarium conspersum and C.ochthodes. The absence of the more oligotrophic Actinotaenium cucurbita and Cosmarium subtumidum is also a feature in common with these clusters.
One might consider cluster 3‑C to be artificial, as many samples of 3‑C are token near each other (see below), reflected in a homogeneous vegetation throughout the cluster and the presence of many 'unique' species. However, vegetation as well as the desmid composition of the clusters 3‑A and 3‑B is closely related to that of 3-C. As the samples of these clusters are token on many different sites, this seems to me an argument to consider cluster 3‑C as a natural one, although perhaps somewhat too pronounced in this case.
Near 'Skogvollvatnet', a lake in the SW‑corner of the investigated area, a small transect was made (the samples 1 to 12), between the 'richer' looking shore of the lake (sample 1) and the edge of an oligotrophic part of the mire (sample 12). In the tables 10, 11, 12 and 13 the data of the samples of the transect are shown. All samples of the transect appeared to group into the clusters of group 3 : respectively 2 in cluster 3‑A, 2 in 3‑B and 7 in 3‑C. The samples of cluster 3‑A were token near the oligotrophic mire, the samples of 3‑C near the lake, and the samples of 3‑B in between. Though not striking, an increase of pH‑value, conductivity, alkality and calcium‑contents along the transect is visible. Other ionic contents show no change along the transect. Apart from sample nr. 12, the vegetation of all samples belongs to the Carex chordorrhiza community.
4.4.5. Group 4
This group is most related to group 3. Group 4 represents the macrophytic vegetation of the flark pools. Much species that occur in group 3 are common here too, but the 'swampy species' lack here. Phragmites australis is much more common. The dominant types of vegetation represent sites that are permanently wet. It's probable that the stability of the environment is the most important discriminating factor between the two groups: a constant presence of a water body with a sufficiently large volume in group 4, vs. a changing water table in group 3, which may cause periods of drought and fluctuating nutrient contents. The habitats belonging to the clusters of group 4 are permanently wet, whether caused by the relative deepness of the water body (cluster 4‑A, 4‑ B, 4‑C) or by the stability of the water level in the shallow waters (also in 4‑B). The chemical analyses indicates oligo‑meso‑ to meso‑eutrophic conditions, but the individual clusters differ considerably. In addition to the species mentioned in the former group, the desmid composition of group 4 is characterized by the occurrence (in all clusters) of Euastrum pulchellum, Cosmarium humile, C.rectangulare var. croasdaleae, Staurastrum lapponicum, S.tetracerum, and Pleurotaenium ehrenbergi . Some species are limited to the clusters of this group: Staurastrum bicorne, Euastrum verrucosum and the non‑constant species Micraterias pinnatifida, Euastrum gemmatum, Cosmarium depressum and Desmidium swartzii..
The state of trophy increases in the sequence 4‑A > 4‑B > 4‑C. Conductivity, pH and Ca2+ ‑, Mg2+ ‑, Na+ ‑ and K+ ‑contents increase in this sequence.
‑ Cluster 4‑A shows the lowest pH‑values, conductivities, Ca2+ ‑ and Mg2+ ‑contents. Its chemistry is quite similar to the poor mesotrophic clusters 3‑A and 3‑B, but pH is higher and Ca2+‑ content lower (!).
‑ Cluster 4‑B Conductivities, Ca2+ ‑ and Mg2+ ‑contents are higher than in 4‑A. These parameters as well as others like pH and SOO24 ‑, Ca2+ ‑, Na+ ‑ and K+ ‑contents are lower than in cluster 4‑C.
‑ Cluster 4‑C is the cluster with the highest trophic status in this group. All chemical parameters just mentioned show higher values than in cluster 4‑A and 4‑B.
‑Cluster 4‑A concerns shore vegetation of larger (>500m2) and deeper (>20cm) flark pools. Often Phragmites australis is present, accompanied by Sphagnum platyphyllum and/or S.annulatum . These mosses may also occur in absence of Phragmites . A number of these pools is part of a series of flarks, separated by small strips of land. Seepage of waters connects these pools. Seepage is indicated by Carex lasiocarpa , which is present on most sampling sites. The occurrence on some sampling sites of Sphagnum annulatum and S. platyphyllum points to the relationship with cluster 2‑A. Cluster 2‑A is dominated by the Drepanocladus procerus‑Sphagnum lindberghii community which also occurs in cluster 4‑A. However, communities indicating 'richer' conditions are dominant in this cluster ( Sphagnum platyphyllum‑Scorpidium community, Scorpidium -community and Carex oederi -community). Other species regularly occurring are Menyanthes trifoliata, Eriophorum angustifolium, Carex limosa, C.livida, Drepanocladus revolvens and Scorpidium scorpioides .
‑Cluster 4‑B. Shore vegetation of large flark pools, as in cluster 4‑A, but with a higher degree of trophy. 'Richer' conditions are indicated by the occurrence of Calliergon trifarium and Carex panicea , while Sphagnum ‑species are absent. Scorpidium scorpioides occurs more frequently than in cluster 4‑A. Other common species: Menyanthes trifoliata, Carex limosa, C.lasiocarpa, and Eriophorum angustifolium. Less frequent are Drosera anglica, Drepanocladus procerus, D. revolvens and Carex rostrata, The Scorpidium scorpioides community occurs as the most frequent one. Part of the vegetation of cluster 4‑B is resembling that of group 3, but the 'swampy species' lack.
‑Cluster 4‑C. Also shore vegetations of larger and deeper waters, with 'richer' conditions than in cluster 4‑B, indicated by the occurence of Utricularia minor, Calliergon giganteum, Chara spec. and Carex diandra. These species indicate calcium richness. Often Drepanocladus purpurascens and Comarum palustre are present, indicating some swamp influence. Other species of importance are Menyanthes trifoliata, Phragmites australis, Carex lasiocarpa, C.limosa, Eriophorum angustifolium, Scirpus cespitosus, Scorpidium scorpioides and Calliergon trifarium. The Scorpidium community and the Chara‑Calliergon community are dominating.
‑Cluster 4‑A. 55 constant species. As in the macrophytic vegetation the desmid composition shows relations with the oligo‑ mesotrophic cluster 2‑A, and even with the oligotrophic clusters of group 1. Species in common are Xanthidium smithii, Tetmemorus brebissonii var. minor, Pleurotaenium minutum, E.pseudoboldtii, E.humerosum, E.denticulatum, Micrasterias truncata and Staurastrum margaritaceum However the degree of trophy of cluster 4‑A is distinctly higher than that of 2‑A (and group 1), indicated by, for example, the occurrence of Closterium cynthia, C.gracile, Cosmarium tinctum and Pleurotaenium rectum. A lot of unique species occur in cluster 4‑A: Pleurotaenium baculoides, Docidium undulatum, Closterium navicula, Euastrum coeselii, E.inerme, Cosmarium contractum var. ellipsoideum, C.quadrifarium and Staurastrum arachne . 9 out of 12 recordings of Pleurotaenium baculoides and 9 out of 10 recordings of Euastrum inerme appeared to belong to cluster 4‑A.
4‑B. 52 constant species. The oligotrophic species of cluster 4‑A
do not occur in this cluster. Typical mesotrophic to meso‑eutrophic
species, which lack in cluster 4‑A are Cosmarium quadratum , C.
crenatum , C. granatum , C. difficile var. constrictum . The most
striking difference with cluster 4‑A is the absence (of course) of
the unique species of 4‑A. Euastrum verrucosum is, as constant species,
limited to this cluster. Cosmarium capitulum var. groenlandicum, Staurastrum
disputatum and S.
‑Cluster 4‑C. 30 constant species. The meso‑eutrophic status is reflected in the absence of species present in all lower degrees of trophy, like Cylindrocystis brebissonii , Tetmemorus laevis and Bambusina brebissonii . Mesotrophic species like Closterium juncidum, C. cynthia, Tetmemorus granulatus, Cosmarium blyttii and C. pseudopyramidatum do not occur. This property is shared with group 5. Probably the high Ca2+ ‑ and K+ ‑contents (or factors correlated with these cations) are responsible for the absence of these species. There are some unique species: Cosmarium regnelli var. minimum , Staurastrum bicorne, S. boreale and S. furcigerum. Cosmarium impressulum and C. portianum occur as constant species just in the calcium‑rich clusters 4‑C and 3‑C.
4.4.6. Group 5
This group consists of two clusters, cluster 5‑A and 5‑B. These clusters are poor in species. The species poorness is caused by extreme conditions, mainly high(er) ionic contents, eventually combined with drought. The pH often shows values above 6. The clusters differ in macrophytic vegetation. Cluster 5‑B concerns spring vegetations, while cluster 5‑A consists mainly of different types of 'rich' flark vegetation. In cluster 5‑B a constant supply of high concentrations of ions is the most important stress factor, while the most important factor in cluster 5‑A is formed by less extreme ionic contents combined with drought. Characteristic in the desmid composition is, besides the absence of many mesotrophic species, the presence in both clusters of Cosmarium anceps and C.speciosum var. biforme. Cluster 5‑A is much richer in species than cluster 5‑B, which in fact is a strongly impoverished version of 5‑A.
‑Cluster 5‑A. The chemistry of this cluster is almost the same as in cluster 4‑C. The NaCl content in cluster 4‑C is somewhat higher. pH values vary between 6 and 7, conductivity may vary, values between 30 and 125 S occur. Likewise the Ca2+ ‑content shows values between 1 and 20 mg/l, but most values are above 4 mg/l. In combination with a high Ca2+ ‑content, high SOO24 ‑ contents may occur.
‑ Cluster 5‑B. Most pH‑values > 6.6, conductivities > 58, up to 550 S . A Ca2+ content > 10 mg/l, also the Mg2+ ‑content often shows high values. Due to the spring influence, most chemical parameters will show constant (high) values. Conductivity, Cll , P.PO24 and Mg2+ ‑contents show higher values than cluster 5‑A.
‑Cluster 5‑A.The vegetations of this cluster are often dominated by mosses like Campylium stellatum, Drepanocladus revolvens, Scorpidium scorpioides and, in one case, Calliergon giganteum. In shallow waters Andromeda polifolia is a common species, likewise Betula nana and Calliergon trifarium . Other species are Carex chordorrhiiza, C. panicea, C. limosa, Eriophorum angustifolium, Scirpus cespitosus and Pedicularis palustris . Different types of meso‑ to meso‑eutrophic communities occur.
‑Cluster 5‑B. The Philonotis community is the most important vegetation type. It represents spring vegetations. Cratoneuron species, as well as Philonotis fontana and Bryum pseudotriquetrum dominate the moss‑layer, and also Drepanocladus revolvens , Campylium stellatum and Riccardia spec. occur frequently. The graminoid and herb layers are heterogeneous. The samples of two sampling sites (139, 156) with a different kind of vegetation (resp. Carex chordorrhiza community and Calliergon sarmentosum‑ Drepanocladus purpurascens community) are put into this cluster. With the other samples of this cluster, they share the desmid‑ species poorness.
‑Cluster 5‑A. 25 constant species. Species that occurred in most mesotrophic clusters and especially in cluster 4‑C, which has practically the same chemistry, lack in this cluster: Cosmarium subtumidum (which also lacks in cluster 3‑C), C. tinctum, C. subundulatum, Euastrum elegans, and Closterium calosporum . Some species are shared only with cluster 3‑C: Closterium parvulum, Cosmarium conspersum and C. ochthodes. Like in this cluster, in cluster 3‑C there is also a periodical 'drought stress', under meso‑eotrophic conditions. Unique species are Euastrum crassicole var. dentiferum, Cosmarium cosmarioides, C. pokornyanum, C. annulatum var. elegans and C. tetragonum .
‑ Cluster 5‑B. 6 constant species. They are Cosmarium anceps, C. hammeri var. homalodermum, C. holmiense var. integrum, C. ochthodes, C. quadratum, and C. speciosum var. biforme.