Soil seed bank of an upland calcareous grassland after 6 years of climate and management manipulations

1. The soil seed bank of limestone grassland plots was investigated after 6 years of manipulation of temperature, rainfall, fertility and disturbance. An inoculum of seeds of species alien to the site was also added to the experiment. 2. The seed bank was largely made up of species that were native to the site and had small, persistent seeds. Large-seeded species, whether native or introduced. were rare or absent in the seed bank. Small-seeded species were generally more deeply buried than large-seeded species. Total seed density was comparable with that of other limestone grasslands. 3. Significant climate effects were few, although the seed bank of the winter annual Arabidopsis thaliana was increased by summer drought and that of Cerastium fontanum was increased by winter heating. 4. The density of seeds of native species declined in response to disturbance and increased fertility treatments, while that of introduced species increased. Changes in the seed bank lagged behind changes ill the vegetation, with introduced species making up a higher proportion of the vegetation than of the seed bank after 6 years of manipulation.