Local topography affects seed bank successional patterns in alluvial meadows

Abstract

Seed banks may play a crucial role in the maintenance of community diversity, but their role on semi-natural grasslands, one of the most species rich habitats in Europe, is usually unexplored in population and community studies. We aim to clarify how local factors and topography influence seed bank successional patterns on semi-natural alluvial meadows. All 35 meadows were situated in the Eagle (Orlické) Mountains in the Czech Republic and were divided according to fallow time. Paired plots, represented low and high topography, were established on each meadow. We recorded plant species occurrence in vegetation and in the seed bank to ascertain how seed abundance, diversity and the similarity between seed bank and vegetation were influenced by topography and management. Seed abundance significantly changed, whereas seed diversity remained stable after meadow abandonment. Seed abundance was high in the low topography plots probably due to higher aboveground biomass which promoted seed accumulation. In the high topography plots, seed abundance was low in managed meadows, but seeds were accumulated after abandonment. Similarity between the seed bank and vegetation was low, but over half of the typical meadow species survived in the seed bank for long periods of time, even when they had disappeared from the aboveground vegetation. In conclusion, the local topography of alluvial meadows influenced seed bank successional patterns, mainly seed abundance, similarity between the seed bank and vegetation and responses of individual species in the seed bank. Seed bank successional patterns are dependent on specific habitat conditions and communities with high seed bank accumulation are more stable and better restored than communities where the seed bank has become severely depleted.