Tapio Lindholm

Ruskorahkasammalen kasvurytmistä Lammin Laaviosuolla

Lindholm T. Ruskorahkasammalen kasvurytmistä Lammin Laaviosuolla.

Tiivistelmä

The growth rate of Sphagnum fuscum growing in the hummocks of an ombrotrophic raised bog was measured. The method used was a nylon textile strip, which was anchored in the peat so that the free end of the strip was above the hummock. The distance of a certain mark in the strip and the capitula of Sphagnum was measured weekly or biweekly. The data presented here are from the years 1976 and 1977. Moreover, the mire water table and daily precipitation was monitored. The annual growth of S. fuscum was about 10 mm, which was quite the same as in several previous studies around the Baltic sea. The importance of immediate moisture for S. fuscum growth was revealed. The correlation between growth and water table was r = 0,59, periods of zero-growth caused by low temperatures excluded. The periods when the growth was dependent only on the water table were grouped linearily on the upper margin of a correlation graph (fig. 2). Thus, they showed the possible maximum growth on different water tables when not restricted by any other factor. The points deviating from the regression line B (fig. 2) have different explanations. Partly they are due to low temperatures in spring and autumn, partly they depict the periods of unfavourable temperature or radiation conditions. Only in one case (1977, 10. fig. 1) the importance of direct seepage water from heavy rains was revealed. The results showed uninterrupted connection between water table and growth medium of S. fuscum. The mosses in general have been supposed to have quite an opportunistic strategy of growth. During the two growing periods studied this was seen concerning S. fuscum, too. There is in the background clear regulation, but, whether this is internally or externally governed, is not possible to conclude from this material and analysis.

Vastaanotettu 31.10.2017 Julkaistu 1.1.1981

Katselukerrat 1202

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