Artikkelit kirjoittajalta Antti Huttunen

An attempt is made in this paper to create two consistent mire typologies, i.e. 1) the Combined Finnish Mire Typology covering all possible mire areas in Finland and 2) the Mire Water Flow Typology for boreal, zonal mire systems, i.e. aapa mires and raised bogs. Furthermore, larger groundwater recharge-discharge patterns concerning mires and the biological significance of morphologic and hydrologic mire classifications are discussed. Zonal mire systems from raised bogs to aapa mires are described as a dominance-based continuum. Local mire systems are subdivided according to factors that impede the formation of mire massifs, which are the essential morphological units of zonal mire systems. Smaller-scale mire units for aapa mires and the acrotelmic flow pattern are presented on the basis of a typical mid-boreal aapa mire system with a raised bog, based on the aerial photograph interpretation. The discussion of the groundwater recharge-discharge pattern and the biological significance of morphologic and hydrologic mire classifications is based on literature.

• Laitinen, University of Oulu, Department of Biology, Botany, P.O.Box 3000, FI-90014, Finland Sähköposti: ei.tietoa@nn.oo
• Rehell, Sähköposti: ei.tietoa@nn.oo
• Huttunen, Sähköposti: ei.tietoa@nn.oo
• Tahvanainen, Sähköposti: ei.tietoa@nn.oo

The present paper introduces and describes a poorly known wetland type – aro wetland – in well permeable mineral soil substratum in Northern Ostrobothnia and Kainuu (between 64° – 66° N lat.). Field observations (linked with the interpretation of aerial photographs) were made in 32 localities, whose conservation status is presented. We define boreal aro wetlands ecologically as a seasonal wetland type of their own which occur on well-drained mineral soil, which are mainly characterised by treeless, mire expanse fen vegetation and in which the peat accumulation is (almost) totally hampered by the vigorous decomposition of the organic matter resulting from an extremely unstable water regime (flood and seasonal drought) and small plant production. Aro wetlands in the western part of the study area occur on sandy substratum (the largest in parts of mire complexes split by ancient raised beach ridges), whereas in the eastern part the aro wetlands known so far are small pond-like depressions in till substratum. Carex lasiocarpa (mostly) dominates the vegetation on sandy substratum. Juncus filiformis and Carex nigra are typical, and Rhynchospora fusca and Molinia caerulea a bit rarer. Sphagnum cover is usually minimal. Considering aro wetlands an extreme case of suo (mire) makes the stability of water regime (stable – unstable) a direction of variation in the traditional Finnish mire site type system, which is based on several ecological gradients.

• Laitinen, University of Oulu, Department of Biology, Botany, P.O.Box 3000, FI-90014, Finland Sähköposti: ei.tietoa@nn.oo
• Rehell, Sähköposti: ei.tietoa@nn.oo
• Huttunen, Sähköposti: ei.tietoa@nn.oo
• Eurola, Sähköposti: ei.tietoa@nn.oo

The results of inventories of drained peatlands have occasioned criticism of profitless drainage. For the better understanding of the mire ecosystem a functional and structural division of mires is presented. This is based on the nutrient cycle, the mire margin — mire expanse-effect, the carbon balance and the community structure of mire sites. The suitability for drainage is discussed on the basis of the ecology. A suggestion is made for further treatment of drained mire complexes. Keywords: Mire classification, mire site types

• Eurola, Department of Botany, Oulu University, SF-90570 Oulu, Finland Sähköposti: ei.tietoa@nn.oo
• Huttunen, Sähköposti: ei.tietoa@nn.oo

The vegetation (mapped with the point method), mire profiles and peat depth are very shortly described (Fig. 2 and 3, tables in the text). Typical of the sloping mires above 300 m a.s.l. are Sphagnum fuscum and Carex globularis spruce-pine mires along the marginal parts of the mire complexes. The middle parts of the mires are often dominated by oligo- and mesotrophic flark fens and Molinia caerulea – Scripus cespitosus – Spagnum compactum - Ptilidium ciliare vegetation; the last mentioned is very similar to the northern boreal short-sedge fen vegetation at the west coast of Northern Norway. Mesotrophic springs and springy patches or stripes are common. All this reflects poor bedrock and hygrid oceanic climate (the temperature climate is continental). This has caused a heavy paludification of the heath (forest) vegetation. Carex-Sphagnum and Sphagnum peats with wood remains dominate usually. Overgrown places can be traced occasionally in the top parts of the mires.

• Eurola, Sähköposti: ei.tietoa@nn.oo
• Huttunen, Sähköposti: ei.tietoa@nn.oo
• Huttunen, Sähköposti: ei.tietoa@nn.oo
• Paasovaara, Sähköposti: ei.tietoa@nn.oo

The material for this study was collected during summer 1974 in Siurua district, near Pudasjärvi, N-Finland (65°30'N/26° 30'E). Sample squares were marked out at regular intervals along the study lines crossing peatlands of different site type. The number of the plants and the berries in each square was then counted. The average weight of the single berries was calculated separately for cloudberry growing in spruce swamps (1,76 g) and for cloudberry in pine and open peatlands (1,30 g). The average weight for cranberry has been calculated using the individual weights of Vaccinium oxycoccos and V. microcarpon (0,756 and 0,293 g respectively) and the average value obtained from the ratio in which they occur in different peatland site types as presented by Ruuhijärvi (1960). The frequency of cloudberry shoots was at its highest in spruce swamps (MrK), in Sphagnum fuscum pine swamps (RR) and in S. fuscum peat banks (S. fuscum-jänne) (Fig. 1). The best yields, about 6—7 kg/ha, were found in the same peat-land site types (Table 1). It is most likely that the beetles and beetle larvae of the Galerucella (Col., Chrysomelidae) had the greatest effect in cutting down the cloudberry yield in Siurua district in 1974. The frequency of occurrence of cranberry shoots was highest in S. fuscum pine swamps, in S. fuscum cotton grass pine swamps (RTR) and in small-sedge bog (LkN) (Fig. 2). The best yields, in turn, were observed in S. fuscum cottongrass pine swamps and in mesotrofic sedge fens (RhSN), being about 40 kg/ha (Table 2). These cranberry yields are much lower than those observed by e.g. Ruuhijärvi (1974). Possible explanations for the difference in the results lie in the methods used and in the large temporal and regional variation in the yields. The total annual cranberry yield in Finland has been estimated at 25—50 mill. kilos and the cloudberry yield at 25—30 mill, kilos. According to the present results the total cranberry yield in nearly 50 mill. kilos and the total cloudberry yield about 5 mill, kilos, which, however, can be at least 3—4 times more in favourable years

• Huttunen, Sähköposti: ei.tietoa@nn.oo

The material used in this study consists of two peat profiles taken from the raised bog at Ylimysneva, Parkano, in south-western Finland (Fig. 1). The correlation between the results obtained from various methods of determining the degree of humification was calculated. The methods used included the humification scale according to von Post (1922), the colon-metric method of Kaila (1956), the bulk density measurements (Päivänen 1969) and the fiber content estimation of Sneddon, et. al. (1971). The negative correlation found between the humification scale according to von Post and the fiber content proved to be statistically highly significant (Fig. 2 and 3). There was a highly significant negative correlation between the fiber content and the bulk density in the case of profile II (Fig. 5) and significant negative correlation with respect to profile I (Fig. 4). The results showed that the fiber content seems to be well suited for measuring the degree of humification. The correlations found between the colorimetric method of Kaila and the other methods were relatively weak (Table 1). This is partly due to the fact that the method is not suitable for use with all the different types of peat. The correlations which were found between the humification degree according to von Post and figures for the bulk density were lower than those reported in the literature. This is very likely caused by layers of charcoal and alluvial material in the peat.

• Raitio, Sähköposti: ei.tietoa@nn.oo
• Huttunen, Sähköposti: ei.tietoa@nn.oo