Suo - Mires and peat vol. 51 no. 4 | 2000

Summary: Organized by The International Peat Society (IPS), The International Asociation of Ecologists (INTECOL ), The International Mire Conservation Group (IMCG), and The Society of Wetland Scientists (SWS), The Millennium Wetland Event held in Québec City, Canada, on 6–12 August 2000 was the biggest ever organized congress devoted to mires and peat. Almost 1900 delegates (with accompanying persons almost 2100 participants) from 75 countries all over the world guaranteed that the programme and sessions were versatile and informative. The 12th IPS congress “Wise use of peatlands” will be organised in Tampere, Finland, between 6th and 11th August 2004 and that is why the Finnish candidate (Markku Mäkelä from Geological Survey of Finland) was elected as the first vice-president of IPS. Gerry Hood from Canada was elected as the president of IPS and Jack Rieley from Nottingham, UK, as the second vice-president for the next four years. In this review some Finnish specialists write about the themes they followed in Québec (Harri Vasander — general, Raimo Heikkilä and Leila Korpela — mire conservation and biodiversity of peatlands, Markku Mäkilä — peat geology, Sanna Saarnio — gas exchange studies, Juhani Päivänen and Sakari Sarkkola — ecology and management of forested peatlands, Arvo Leinonen and Pirkko Vesterinen — peat technology, Olli Reinikainen — horticulture, Juhani Päivänen — wise use of peatlands, Lasse Aro — restoration of peatlands and the post-congress excursion). The Millennium Wetland Event was considered to be a unique opportunity to visit, meet collegues and to update knowledge about mire and peat science. A great thank you for all the organisers of this magnificant occasion. Un grand merçi pour tous les organisateurs du congrès: "Évènement du millénaire sur les terres humides". C’était une occasion inoubliable et un excellent début pour le nouveau millénaire.

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

The occurrence of raw humus layer and its relationship to the structure of the vegetation and the environmental variables were studied on 501 sample plots located systematically in drained peatland forests. The drainage had been done in the 1930s – 60s. The correlation between the amount of raw humus and the two-dimensional GNMDS (global nonmetric multidimensional scaling) ordination space was 0.57. The thickness of the raw humus layer increased in the direction of the drainage succession gradient. The correlations between the thickness of the raw humus and the measured environmental variables were weak. The strongest correlation was with the stand volume (0.31) and the drainage age (0.21). Weakness of these correlations was most probably due to the regressive succession on many plots. On average, the raw humus layer was thickest , 6.5 cm, in Vaccinium vitis-idaea transformed type I (developed from genuine forested mires) and 5.4 cm in type II (developed from treeless or composite types). In Vaccinium myrtillus types the corresponding mean thickness was 5.2 cm (I) and 3.2 cm (II) and in dwarf-shrub types 3.3 cm (I) and 4.6 cm (II). The secondary succession is slower and the amount of the needle litter (of Pinus sylvestris) smaller in the dwarf-shrub type than in the V. vitis-idaea type. In the V. myrtillus type the origin of the litter is more dominated by deciduous trees, the decomposition faster and the coverage of Pleurozium schreberi clearly smaller than in the nutrient-poorer types. P. schreberi tolerates the litterfall well and together with especially conifer litter, and maybe with slow decaying fine roots, too, it forms a loose raw humus layer on old drained peatlands. Being a poor germination bed, the raw humus makes successful stand regeneration difficult.

• Saarinen, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Hotanen, Sähköposti: ei.tietoa@nn.oo

Both minerotrophic (fens and transitional mires) and ombrotrophic (raised bogs) mires occur in Latvia. Distribution of mires and diversity of mire vegetation are determined by geology of area, origin of mires and climatic differences between coastal and continental parts of Latvia. Fens started to develop in the early Holocene in the Preboreal 10 000 years BP. Later, during the Atlantic many fens transformed into transitional mires and gradually into raised bogs. Today Latvian mires are represented by all these types and they cover 4.9% of the country. Mires are protected in the North Vidzeme Biosphere Reserve, National Parks (Slitere, Kemeri and Gauja), Strict Nature Reserves (TeiEi, Krustkalni and Gripi), Nature parks and 140 nature reserves, as well as in protected landscape areas.

• Pakalne, Department of Botany and Ecology, university of Latvia, Kronvalda Boulevard 4, LV-1586, Riga, Latvia Sähköposti: ei.tietoa@nn.oo
• Kalnina, Sähköposti: ei.tietoa@nn.oo