Artikkelit kirjoittajalta Antti Reinikainen

Mire margin communities are mosaics of forest and mire vegetation which consist of several ecological guilds (forest, spruce mire, marsh and spring vegetation). Diversity patterns of undrained forested mire margin communities were examined by using numerical classification (TWINSPAN) and ordination (DCA) techniques. The understorey vegetation was tested for both alfa (species richness, Shannon H' and Pielou J diversity indices) and beta diversity (DCA dimensions). The structural diversity of the overstorey was examined by producing structural (TWINSPAN) clusters based on the percentage cover of tree and shrub species in six canopy layers and in one shrub layer. The study was based on the systematic sample plot data collected from permanent plots of the 8th Finnish National Forest Inventory (1985-86). The material consisted of 92 plots of undrained forested mire margin sites in south and central Finland (60o-66o). The alfa diversities between the seven site clusters differed more clearly than those between the site types. A considerable variety of species of different ecological guilds were found that represented the ecological sources of high beta diversity. Structural diversity varied between clusters formed from overstorey data.

• Korpela, The Finnish Forest Research Institute, Vantaa Research Center, P.O.Box 18, FIN-01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo
• Reinikainen, Sähköposti: ei.tietoa@nn.oo

A review of the historical development of mire site classification in Finland with special emphasis on the studies and theories of post-drainage succession is made. Some criticism of the prevailing classification system is presented and a work model for guiding further study of drained mire classification is proposed. Preliminary results of a new approach to classify the vegetation of old peatland forests using TWINSPAN classification and DCA ordination techniques are presented. Keywords: Drainage, mire classification, site type, succession

• Reinikainen, The Finnish Forest Research Institute, Department of Peatland Forestry, P.O. Box 18, SF-01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo

A survey about the recent state of the importance of mire-ecosystem models in Finnish circumstances was made. The developmental level of the models in question was in early 1970ies not very high. They were working models based mainly on the general sketches on an ecosystem. The task of the study project presented in this paper (Suo 4—5/1981) was to collect empirical raw material to relevant models of certain basic structures and functions of southern boreal mire-ecosystems. The project succeeded in giving dimensions and levels of the parameters concerning primary production of the mires in question. A dynamic model of the primary production of the whole community in a raised bog is being constructed. With regard to the decomposition pool some basic data on soil animal populations was collected, and the total decomposition was tried to determine. The vertical environmental gradients in the peat were found to be important. Although the results of the project could not much improve the models of ecosystem functions (Fig. 2) empirical material was produced available for mathematical modelling.

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

On the basis of case material collected in the studies of Kosonen (1976), Ouni (1977), Vasander (1981a) and Solmari (unpubl.) and with references to Paavilainen's (1980) material a review was made on the primary production patterns of mires ameliorated for forestry (Fig. 1). The available data represented poorly the variation of mire types, fertility classes, improvements and succession time. As first examples from c. 5,3 million hectares of ameliorated mires in Finland the results were published. The total biomass and tree-biomass increased parallelly being dependent on site type, original tree stand, treatment and time (Fig. 1, Table 1). The biomass of lower vegetation layers developed more irregularly. The field layer with changing species composition maintained its biomass better than the ground layer, which suffered most from the decreasing moisture and increasing canopy shadow. Along all the succession the proportions of lower vegetation in biomass decreased steeply. In 40—60 years the biomass distribution reached appr. the state of pine forests on mineral soils. Higher biomass of field layer was a reminder of mire succession. Above ground production (Fig. 1, Table 1) changed less than the biomass, but mainly increased. The total efficiency of the community was after drainage 103— 187 %, and after additional NPK fertilization 150— 230 %, of that in virgin mire type. The distribution of primary production changed so that the proportion of tree biomass increased. However, the amount of stem growth did not increase in the same degree.

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

The background, establishment, organisation, study strategy and topics of a project carried out from 1973 to 1981 was described (for more details, see Ruuhijärvi et al. 1979). Initially the Finnish Forest Research Institute supported the project. Since 1978 it has been financed by the Academy of Finland, and working facilities and equipment were provided by the Forest Research Institute, Lammi Biological Station, and the Institutes of Botany and Zoology at the University of Helsinki. The studies concentrated on the primary production and the decomposition of mire ecosystems mainly in the virgin state, but examples of amelioration successions were also analysed. The study sites (Table 1) were selected from the area of southern boreal mires, mainly within the zone of eccentric raised bogs (Fig. 1). This number of the periodical ""Suo"" contains the main results and summaries of the separate studies made within the project. The classification of site types was the Finnish one and the type names were used in the Finnish form. Therefore, it is essential to study the Table 2 in this article. "

• Ruuhijärvi, Sähköposti: ei.tietoa@nn.oo
• Reinikainen, Sähköposti: ei.tietoa@nn.oo

In the paper, a preliminary model of the structure and function of a boreal mire ecosystem is presented. In addition, a research plan leading to the model is described. In the exploitation and management of natural resources, information about the ecosystem as a functional unit is needed, if ecological principles are to be applied. In Finland, mires (peatland ecosystems) have been subject to exceptionally severe exploitation since forest drainage and fertilization effectively started in the 1960's, However, mires represent one of the least known ecosystems. The mire ecosystem has been defined according to Ellenberg's (1973) criteria as follows. A mire is an ecosystem maintained by cool and humid local climatic conditions and a high water table, which results in deficient decomposer activity and accumulation of organic matter (peat-forming process). The most striking features in the energetics of the system are a relatively ineffective input of energy and an even more ineffective use of it. This is indicated in the metabolism of the system by an excess production of oxygen and, in addition, by losses in the carbon, mineral, and nitrogen cycles. A general model of the mire ecosystem is presented in Figure 1, which simultaneously serves as a framework for the study. The individual parts of the project are planned to be as follows: (1) environmental factors, (2) plant community and primary production, (3) secondary production, in which (3a) energy flows through herbivores, and (3b) energy flows through decomposers, (4) nutrient cycle, (5) the accumulation of peat, and (6) succession in the mire ecosystem. In (1), special attention has been paid to factors characteristic of mires, especially the factors connected with the water table. As the aim of the study is to obtain a dynamic model of a biotic phenomenon, emphasis has been put on the continuous observation of environmental factors. In (2), a graphic model (Fig. 3) has been chosen as the primary goal. Graphic models of a few peatland site types based on preliminary studies already exist. When constructing dynamic ecosystem models, the growth rhythm of the plant communities is the most important study object. Some advances in the methodological development of measuring the growth of mire plants have been achieved. For instance, the problems involved in measuring the height growth of Sphagnum mosses in field conditions have partly been solved. An application of the IRGA-technique to studying the organic matter production of the Sphagnum — dwarf shrub community is ready for use in field conditions, but the methods for combining direct measurement data with IRGA results are still inadequate. The main task in (3) is characterized by Figure 2, i.e. energy flow and material should be divided into biotic components. By using population studies, decomposition tests, and experimental respiration techniques, a more detailed quantitative model of these pathways can be constructed. Preliminary results for total decomposer activity and the role of soil animals in detritus energy flow have already been revealed. Branches (4) and (5) are very closely connected with each other and with (3b). A detailed study into the different terms which make up the accumulation equations as a function of the environmental factors has been proposed. In (6), the suitability of the mire ecosystem as a study object of stability and succession problems has been emphasized. The successio-nal stage of the ecosystem is very strongly affected by forest improvement measures. For this reason, the study of the regulation mechanisms of mire communities is important in Finland, where about 4.5 mill. ha. out of a total of 10 mill. ha. have been drained and partly fertilized so far for forestry purposes. Finally, the future of the planned research project The structure and function of mire ecosystems and the effects of forest improvement on them is discussed. The working group consisting of biologists from the Finnish Forest Research Institute (Department of Peatland Forestry) and from a number of departments at Helsinki University (Botany, Zoology, Microbiology) is waiting for the research plan, now connected with the MAB-program of Finland, to be financed. The preliminary studies are continuing on a small scale.

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