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Regeneration by seeds in alpine meadow and heath vegetation in sub‐arctic Finland
Authors:Pirjo Welling  Kari Laine
Abstract:Abstract. This paper compares the regeneration by seeds of heath and meadow and studies relationships between the floristic composition of phases in the regeneration pathway. Seed densities in the seed rain and seed bank as well as the densities of emerged seedlings in gaps and in closed vegetation were greater in the meadow than in the heath. In the heath, environmental constraints hindered seedling emergence almost completely so seeds accumulated in the seed bank. In the meadow, the decrease in the seed bank was due to high seedling emergence. Within both plant communities, seedling emergence in gaps and in closed vegetation was comparable. In the meadow, the seed rain and seedling emergence in gaps, as well as the seed bank and seedling emergence in gaps were positively correlated. Differences in seed and adult plant sizes were reasons for the low correlation between the standing vegetation and the other phases. In DCA ordination the first axis separated the phase of seedling emergence in closed vegetation and seed bank. The second axis separated the standing vegetation from the other phases. The structure of the seed rain was more heterogeneous than that of other phases. In the heath, the standing vegetation and the seed rain were positively correlated. The ordination of these phases reflected the patchiness of standing vegetation and the ability of the diaspores of Betula nana to disperse over long distances.
Keywords:DCA  Disturbance  Seed bank  Seedling emergence  Seed rain    met‐Ahti et al  (1998)
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