Seed bank dynamics in grassland created on arable land

Previous studies suggest that soil seed banks play an important functional role in the continuous regeneration of many grassland plant species, and that high densities of non-target species in the soil seed bank can have a profound effect on the establishment of sown target species. Here, we investigate the seed bank dynamics of functional groups of both sown and unsown species during 7 years of grassland restoration at three lowland grassland sites, and in particular the effects of seed mixture and of pre-sowing soil cultivation on these dynamics. We found that use of species-rich mixtures containing both grasses and forbs resulted in a much faster accumulation of sown forb species in the seed bank. By contrast, contrary to our expectation of reduced numbers of unsown seeds after deep cultivation, type of soil cultivation did neither affect the dynamics of both sown and unsown forbs and grasses, nor the dynamics of unsown Juncus spp.