Metla Project 3222
Impact of forestry and environmental change on the diversity of boreal vegetation since 1950
Keywords: biodiversity, environmental gradient, forest vegetation, measurement of diversity, mire vegetation, remote sensing, successio, vegetation change, vegetation monitoring
Objectives The main goal of the project is to analyze the changes of forest and mire vegetation in Finland since 1950 and explain those changes by environmental conditions and land use factors. In addition, methods of vegetation monitoring based on remote sensing will be developed as well as new approaches to the mathematical analysis of vegetation and image data.
Results The change of forest and mire vegetation has been analyzed at three hierarchic levels: species ecology, community dynamics and regional changes. The ecology of certain core species, especially dwarf-shrubs has been studied intensively both along natural nutritional gradients and pollution gradients in heavy metal deposition areas. The responses observed in the intensive species ecological studies were utilized when the results of regional inventories were interpreted.
At the community level the project was concentrated on the changes in the mire vegetation. The changes which were due to peatland drainage for forestry purposes have decreased the diversity of vegetation by making the communities more similar to those of mineral soil forests. Especially the decrease of mire-margin influenced sites has affected the total diversity. In studies concerning the mire types of northern Finland the post-drainage succession was found to be slower than in southern part of the country but leading to similar results along the time.
The large scale regional changes in species frequencies and abundances were analyzed from the data of three national forest inventories, 1951-53, 1985-86 and 1995. Drastic changes among the most common forest and mire species were observed. The findings were in broad outline explained by the impact of modern forestry and by the changes in the land use. The species of old forests, most barren forest sites and genuine mire sites have decreased most clearly. Species gaining the most advantage were the pioneer plants of young forests, some herbs favoring fertile sites and the forest plants on drained peatland sites. The results have been published in the book ‘Kasvit muuttuvassa metsäluonnossa’ (Summary: Changes in the frequency and abundance of forest and mire plants in Finland since 1950).
The results of vegetation studies have been utilized also in the analysis of carbon cycle and balance at national and global levels.
Several new methodological approaches have been presented. Digitalized photographs were used in the interpretation of small scale variation of forest vegetation. Combined use of satellite images and vegetation data was tested for evaluating the value of key biotopes and local biodiversity.
Haakana, Markus, HE (2002), Hamberg, Leena (2002), Hartman, Markus, VA (1999-2000), Heikkinen, Juha, HE (1997-2001), Heinonen, Riitta, VA (1998), Hotanen, Juha-Pekka, JO (1998-2003), Joensuu, Johanna (2002), Jämsen, Leena (2002), Korpela, Leila (1997-1999,2001-02), Luque, Sandra, HE (2001-02), Mikkola, Kari, RO (1998-99), Moilanen, Juhani, HE (1999-2000), Mäkipää, Raisa, HE (1997-2003), Mäkisara, Kai, HE (1999,2001), Nousiainen, Hannu, VA (1998-2003), Paracchini, Maria (2000-01), Riutta, Terhi (2002), Salemaa, Maija, VA (1997-2003), Silfverberg, Klaus, VA (1999), Strandström, Mikael, HE (2002), Tomppo, Erkki, HE (1997-2001), Tonteri, Tiina, VA (1997-2003), Vanha-Majamaa, Ilkka, VA (1998-2000)
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