I studied the vegetation and seed bank in an 18-yr-old, replicated exp
eriment with grazed and ungrazed plots in a semi-natural, perennial gr
assland in southern Sweden. In the ungrazed plots, a tall (16-20 m) an
d dense tree layer had developed. There were fewer plant species growi
ng in ungrazed plots than in grazed plots, but the difference was not
significant. However, the number of species per square metre was signi
ficantly lower in ungrazed plots. Hence, on a smaller scale, the groun
d vegetation had become less diverse, but on a larger scale few specie
s had been lost. In the seed bank, a few species lost from the vegetat
ion were still present as seeds in the soil, but in most cases species
lost were not recorded in the seed bank. Seeds of species that had co
lonized plots over the 18 yr were evenly distributed in the soil betwe
en the upper (0-4 cm) and lower (4-8 cm) sampling depths. Most of the
seeds of species that had disappeared from plots were deep in the soil
. Hypotheses about changes in the seed bank during secondary successio
n, predicting decrease in species richness and seed density, were not
confirmed.