Hidden biodiversity in the Arctic – a study of soil seed banks at Disko Island, Qeqertarsuaq, West Greenland
Marianne Philipp, Kjersti Hansen, Dorte Monrad, Henning Adsersen, Hans Henrik Bruun, Inger Nordal
Seed dispersal is a key process in plant community dynamics, and soil seed banks represent seed dispersal in time rather than in space. Despite their potential importance, seed bank dynamics in the Arctic are poorly understood. We investigated soil seed banks and corresponding plant community composition in three contrasting vegetation types in West Greenland, viz. dwarf shrub heaths, herb slopes and fell-fields. Through germination testing, 31 species were documented in soil seed banks. All of these were herbaceous, while no dwarf-shrub species, which represents the dominating growth form in the above-ground vegetation, were emerging from the seed bank. Consequently, across vegetation types, the lowest similarity between seed bank and above-ground vegetation was found in dwarf shrub heath. Nine plant species were exclusively found in seed bank, all of which were non-clonal forbs. Seed bank size (total number of seeds) and species richness seemed to increase with the level of natural disturbance. Additionally, we examined the effect of different experimental light and temperature conditions on the quantity and diversity of germinating seeds. The difference in diversity in vegetation and seed bank at the species level will impact population dynamics, regeneration of vegetation after disturbances and its potential to respond to climate change.
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