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Atlantic raised bogs lack the marginal forest and often a typical lagg, and occur in a typical form in the most oceanic sections of Norway. Transitional types to other types of raised bogs are common in the fjord districts.

Blanket bogs (group B: 1-2) are defined sensu stricto, i.e. they are bog massifs that have a distinct mound in their topography or an area sloping at a minimum angle of 3g. Blanket bogs are found in the most oceanic parts of Norway, in the boreonemoral, southern boreal and middle boreal vegetation zones. In the highly oceanic section, large areas of blanket bog was established after clearing, burning and livestock grazing from about 2700 years ago (Solem 1989); inland blanket bogs (in markedly oceanic section of upper boreal) are older (Solem 1991).

Plane bogs (group B: 3-4) are bogs that are not distinctly domed or blankets; they are often transitional to other types.

Mixed mires (group C) consist of a mixture of bogs and fens. String mixed mires (as well as D7 flark fens) are most common in continental parts of the middle and northern boreal areras; a map showing their distribution in southeast Norway can be found in Nss (1969). Palsas have ice lenses which remain frozen throughout the year; they only occur in continental areas where the mean O3t O3h O2 O1 OC C1 O3t O3h O2 O1 OC CHA HA MA MA LA/SA LA/SA NB NB x MB x x MB X x SB X X X X X SB X BN X X X X X BN X X N X X N X I Raised bogs II Blanket bog O3t O3h O2 O1 OC C1 Figure 1. Schematic representation of the 36 vegetation ecological regions occurring in Norway. Vertical units show the HA vegetation zones: N nemoral; BN boreonemoral; SB southern MA boreal; MB middle boreal; NB northern boreal; LA/SA low LA/SA X X alpine/southern arctic; MA middle alpine; HA high alpine.

NB X X Horizontal units show the vegetation sections: O3 Highly oceMB anic (t winter-mild subsection, h humid subsection); OSB markedly oceanic; O1 slightly oceanic; OC indifferent; CBN slightly continental.

N X: common occurrence; x: rare III Palsa mires Figure 3. Schematic presentation of the main hydromorphological mire types. The vertical scale is strongly exaggerated. Bottom left-hand corner: an ombro-minerotrophic mire system consisting of three mire massifs. On the left an eccentric raised bog, on the right a plane bog, and in the middle a flat fen. The three types of mire sites present (lagg, marginal forest and bog expanse) are annual temperature is below 1 C. Typical palsa mires (with 67 m high palsas) are restricted to the north-eastern part of northern Norway (Eurola & Vorren 1980), but a few small palsas also occur in some mountains in continental districts of central Norway (cf. the distribution map in Sollid & Srbel (1998)).

Fens (group D) are minerotrophic mires and are found wherever mires occur. By using hydrological and peat-forming processes connected with them, Mikael Succow (e.g. in Succow & Joosten 2001) subclassified the minerotrophic mires into six "hydrologic-biogenetical" mire types (+ spring mires). D1-5 were often classified as "Flat fens". Sloping fens are common outside the most continental parts of Norway, covering large areas in the middle and northern boreal zones and the lower part of the low alpine zone. The most strongly sloping fens (inclination of more than 15g) occur in the most oceanic parts of Norway, in areas with much precipitation and a long-lasting snow cover. Moen (1990: 22) has a distribution map for central Norway.

Springs (group E) are included as a type of mire here.

Table 1. The various hydromorphologically defined mire (and spring) types found in Norway. Eccentric features are regular, but not circular. Mainly based on Moen (1985); fen types after Succow & Joosten (2001).

A. Raised bogs (convex, with more or less distinct dome) 1 Concentric raised bog 2 Eccentric raised bog 3 Plateau raised bog 4 Ridge raised bog 5 Atlantic raised bog B. Non-raised bogs (not distinctly domed, including blanket bogs and plane bogs) 1 Mound blanket bog 2 Sloping blanket bog 3 Eccentric plane bog 4 Other plane bog C. Mixed mires 1 String mixed mire 2 Islet mixed mire 3 Palsa mire D. Fens (minerogenic mires) 1 Terrestrialisation fen 2 Swamp fen (flat fen) 3 Kettlehole fen (flat (lake fen) fen) 4 Transgression fen (flat 5 Percolating fen < 3g 6 Sloping fen (percolatfen) ing fen > 3g) 7 Flark fen (percolating fen with flarks and strings) E. Springs 1 Astatic spring 2 Eustatic spring Vegetation units The Scandinavian tradition, after e.g. Sjrs (1948), uses an ecologically based conception, distinguishing between ombrotrophic and minerotrophic vegetation as the main limit. Further the mire vegetation is differentiated in three local vegetational gradients (poor-rich, expanse-margin, hummock-mud bottom). In the Norwegian plan for mire nature reserves, we separate 25 mire and spring vegetation units based on these gradients; tables of species groups defining the different units, ecograms and further descriptions are given in e.g.

Moen (1985, 1990) and Moen & Singsaas (1994).

Red list of mires A report on threatened vegetation types in Norway was published in 2001 (Fremstad & Moen 2001) using the categories of threat employed by the IUCN. Descriptions and assessments were based on published and unpublished material, and 18 Norwegian botanists participated. Seventyone types of vegetation and 68 subtypes of these were red-listed and described. The evaluation of Norwegian mires was made by four mire ecologists (cf. Moen et al. 2001). Satisfactory documentation and information on hydromorphological and vegetational types and subtypes are lacking in Norway, and the group could not make a detailed typification.

The mires in Norway are extremely varied and more knowledge is urgently needed. Three groups of mire vegetation and three main types of hydromorphological mires are included in the Red List:

1. Wooded or scrub-covered intermediate and rich fens are classified as vulnerable (VU); subtypes in nemoral, boreonemoral and southern boreal vegetational zones are regarded as endangered (EN).

2. Open intermediate and rich fen in the nemoral, boreonemoral and southern boreal zones are regarded as VU; some subtypes are classified as EN and critically endangered (CR) (e.g. extremely rich fens).

3. Extremely rich fen in uplands (middle boreal - low alpine zones) are classified as low risk (LR); subtypes as EN.

4. Raised bogs are classified as EN.

5. Blanket bogs and other types of oceanic bogs are classified as EN.

6. Palsa mires are classified as EN; in south Norway as CR.

In addition, all springs of lowland type (mainly occurring in the nemoral, boreonemoral and southern boreal zones) are classified as EN. A number of types of freshwater vegetation are also included in the Red List.

Mire area and preservation In the 1920s, the total area of mires in Norway was estimated to be 30 km2 (nearly 10 % of the land surface), 21 000 km2 of which were situated below the forest limit. More than 6 500 km2 of the original mire area in Norway have been drained, mainly for agricultural and forestry purposes.

Surveys in connection with the Norwegian national plan for mire nature reserves began in 1969 under the auspices of the Ministry of the Environment. More than 40 primary reports have been published (written in Norwegian, usually with an English summary) describing the localities investigated in the 19 counties of Norway. A description in english of the preservation plan and results for mire nature reserves in Norway, including methods, criteria for site selection and overall assessment, are given in Moen (1995b).

The two main criteria for mire preservation in Norway have been: a) conservation of representative mire ecosystems within the different vegetation regions of Norway, b) preservation of interesting, unusual or extreme mire ecosystems. The national plan for mire nature reserves has been completed for 18 of the 19 counties and comprises 278 localities (554 km2), i.e. less than 2 % of the mire area. In addition, mires are protected in wetland reserves (at present 323 localities), national parks, etc., covering altogether more than 5 % of the mire area in the country. However, most of these are upland/alpine mires, whereas lowland mires in the south and west are most threatened.

Restoration work (e.g. blocking of ditches) has been carried out in a few reserves. In the Slendet Nature Reserve in the eastern part of central Norway, an area of 160 ha has been restored as a former hay-making fen; the area has been regularly mown for the last three decades. Slendet is now an important reference site for knowledge about the effect of scything (Moen 1990). However, the great majority of mire reserves have no management plan and a large number of them require such a plan to protect their natural qualities, including rare and threatened species (e.g. many orchids).

References Cajander, A.K. 1913. Studien ber die Moore Finnlands. Acta For. Fenn. 2: 1208.

Dahl, E. 1957. Rondane. Mountain vegetation in South Norway and its relation to the environment. Skr. Norske Vidensk. Akad. Mat.-Naturv. Kl. 1956-3: 1374.

Du Rietz, G.E. 1954. Die Mineralbodenwasserzeigergrenze als Grundlage einer natrlichen Zweigliederung der nord- und mitteleuropischen Moore. Vegetatio 5-6: 571-585.

Eurola, S. 1962. ber die regionale Einteilung der Sdfinnischen Moore. Ann. Bot. Soc. Vanamo 33-2: 1-243.

Eurola, S. & Vorren, K.D. 1980. Mire zones and sections in North Fennoscandia. Aquilo Ser. Bot. 17:39-56.

Fremstad, E. & Moen, A. 2001. Truete vegetasjonstyper i Norge. Univ.

Trondheim Vitensk.mus Rapp. Bot. Ser. 2001-4: 1-231.

Gore, A.J.P. (ed.) 1983. Mires: swamp, bog, fen, and moor. A & B. Ecosystems of the world. 4A & 4B. Elsevier, Amsterdam. 440 pp. + 479 pp.

Ivanov, K.E. 1981. Water movement in mirelands. Academic Press, London.

276 pp.

Lindsay, R. A. et al. 1988. The Flow Country. The peatlands of Caithness and Sutherland. Nature Conservancy Council. Peterborough. 174 pp.

Malmer, N. 1962. Studies on mire vegetation in the Archaean area of southwestern Gtaland (South Sweden). I. Vegetation and habitat conditions on the khult mire. Opera Bot. 7-1: 1-322.

Masing, V. 1984. Estonian bogs: plant cover, succession and classification. In Moore, P.D. (ed.) European mires, pp. 119-148. Academic Press. London..

Moen, A. 1985. Classification of mires for conservation purposes in Norway. Aquilo Ser. Bot. 21: 95-100.

Moen, A. 1990. The plant cover of the boreal uplands of Central Norway. I.

Vegetation ecology of Slendet nature reserve; haymaking fens and birch woodlands. Gunneria 63: 1-451, 1 map.

Moen, A. (ed.) 1995a. Regional variation and conservation of mire ecosystems. Gunneria 70: 1-344.

Moen, A. 1995b. The Norwegian national plan for mire nature reserves: methods, criteria and results. Gunneria 70: 159-176.

Moen, A. 1999. National Atlas of Norway: Vegetation. Norwegian Mapping Authority, Hnefoss. 199 p.

Moen, A. & Singsaas, S. 1994. Excursion guide for the 6th IMCG field symposium in Norway 1994. Univ. Trondheim Vitensk.mus Rapp. Bot. Ser.

1994-2: 1-159.

Moen, A., Skogen, A., Vorren, K.-D. & kland, R.H. 2001. Myrvegetasjon (Mire vegetation). In Fremstad, E. & Moen, A. (eds.) Truete vegetasjonstyper i Norge (Threatened vegetation types in Norway), pp. 105-124. NTNU Vitensk.mus. Rapp. Bot Ser. 2001-Nss, T. 1969. stlandets myromrder - utbredelse og morfologi. In Myrers kologi og hydrologi, pp. 75-88, 3 plates. IHD. rapp. I. Oslo.

kland, R.H. 1990. Regional variation in SE Fennoscandian mire vegetation. Nord. J. Bot. 10: 285-310.

Ruuhijrvi, R. 1960. ber die regionale Einteilung der nordfinnischen Moore. Ann. Bot. Soc. Vanamo 31-1: 1-360.

Sjrs, H. 1948. Myrvegetation i Bergslagen. Acta Phytogeogr. Suec. 21: 1-299.

Solem, T. 1989. Blanket bog formation on Haramsy, Mre & Romsdal, Western Norway. Boreas 18: 221-235.

Solem, T. 1991. Blanket mire formation on a drumlin in Nord-Trndelag, Central Norway. The Holocene 1-2: 121-127.

Sollid, J.L. & Srbel, L. 1998. Palsa bogs as a climate indicator - Examples from Dovrefjell, Southern Norway. Ambio 27-4: 287-291.

Succow, M. & Joosten, H. 2001. Landschaftskologische Moorkunde. 2nd ed. Schweizerbartsche Verlagsbuchh., Stuttgart. 622 pp.

Tuomikoski, R. 1942. Untersuchungen ber die Untervegetation der Bruchmoore in Ostfinnland. I. Zur Metodik der pflanzensoziologischen Systematik. Ann.

Bot. Soc. Vanamo 17-1: 1-203.

Yurkovskaya, T. 1995. Mire system topology for use in vegetation mapping. Gunneria 70: 73-82.

THE FINNISH MIRE SITE TYPE CLASSIFICATION SYSTEM R. RUUHIJRVI1 & T. LINDHOLMDepartment of Biology, University of Helsinki, rauno.ruuhijarvi@kolumbus.fi Finnish Environment Institute, Helsinki, Finland tapio.lindholm@ymparisto.fi The development of Finnish mire classification.

The botanical mire science is in Finland more than a hundred years old.

The mire site classification was developed in the beginning of 1900s by A. K.

Cajander (1906, 1910, 1911a,b, 1913, 1916). That was deveped together with forest site type system (Cajander 1909). At that time there was a need to know more about the ecology of mires for the utilization of them for in agriculture and for forestry. In this task a special terminology was needed and the rich and specific terms in dialects of Finnish language was noted to be good for this purpose. The lack of corresponding terms and thinking in other languages causes difficulties in describing the variety of Finnish mires in other languages.

Cajander had not a direct background in his work. However, his professor and teacher J. P. Norrlin had in his lectures and in publications (1870, 1871) described the four main groups of mire sites. Also the raised bog monograph by C. A. Weber (1902) was familiar to Cajander.

Cajanders personal concept of mires developed during his large expeditions in different parts of Finland, Russian Karelia, Archangel region and in Siberia. In his main work of mires "Studien ber die Moore Finnlands" (1913) contents a description of 75 mire site types and in a later important work "Metsnhoidon perusteet I" (The elements of silviculture, part I) (1916) the number of mire site types is 87. Later, two main groups of mires, (i.e flooded swamps and spring mires) have been added (e.g Eurola & al. 1994) in the system beside the original four main groups (i. e.

pine mires (including bogs) Raisermoore - rmeet, forest (=spruce) mires Bruchmoore - korvet, fens. Weissmoore - nevat and rich fens Braunmoore - letot).

Mire site types have been defined to be vegetation types characterized by similar vegetation and ecological conditions. The system is flexible. For different purposes they can be defined by a more wide or by a more narrow way.

The development of Finnish mire site type classification system can be seen in different mire site guides which have been published during the last 70 years for the purposes of different inventories of agriculture, peatland forestry and biodiversity (e.g. Lukkala & Kotilainen 1945, 1951, Kivinen 1948, Heikurainen & Huikari 1960, Eurola & Kaakinen 1978, Eurola & Holappa 1985, Eurola & al. 1994, Laine & Vasander 1990, 2005). Finnish mire site type system has also presented in international textbooks (Ruuhijrvi 1983 and Eurola & al. 1984.) The Finnish mire site classification system has not been much studied from the point of theoretical vegetation science. The almost forgotten classic of that approach is the academic dissertation of Risto Tuomikoski (1942), in which he using forest mire (Bruchmoore) vegetation as an example studied the character of mire margin vegetation and its systematics. Tuomikoskis main arguments were multidimensional coordinates of forest mire vegetation and he emphasized the serial order of different plant species and species groups, which is studied by positive and negative correlations. For Tuomikoski classification is always based on an agreement and needed only for the terminology and communication. By this argumentation Tuomikoski was very modern and ahead of his time.

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