Effects of experimental and real land use on seedling recruitment of six fen species

Seedling emergence and early establishment of six fen species differing in seed mass and growth form were investigated under experimental. land use with changed vegetation structure and under real land use in a catcareous fen. Seeds of all. six species were sown in plots with different experimentat Land-use treatments: summer and autumn mowing with or without titter removal, trampling and abandonment. Additionally, emergence and survival of experimentally sown seeds was investigated under real land use on adjacent sites managed by mowing, grazing, intense trampling or abandonment. On abandoned plots and on plots without Litter removal of the land-use experiment, emergence rates of all species were negatively affected either by high titter and moss cover or by tall canopy. No differences were found between autumn and summer mowing. Gap creation by experimental. trampling did not increase germination rate. Under real Land use, establishment of seedlings of most species was positively affected by titter cover and tall canopy. Trampling, in contrast, had a severe negative effect on seedling survival. The investigated species differed in their germination ability which was tested in the germination chamber and in their response to land use. Succisa pratensis with the highest seed mass germinated well in the chamber and in the field more or less regardless of land use. The tow germination rate of Parnassia palustris in the germination chamber indicated a limitation of viable seeds. In the field, however, seedling emergence was additionally limited by microsite avaitability. Seeds of Serratula tinctoria and Primula farinosa germinated well in the, germination chamber, but seedling recruitment in the field was hampered in the presence of a high titter or moss cover. Seeds of Tofieldia calyculata and Pinguicula vulgaris were strongly dependent on the availability of suitable microsites in the fiel.d. They hardly germinated under natural conditions, in spite of a high number of germinabte seeds in the germination chamber. (c) 2005 Gesettschaft fOr Okologie. Published by Elsevier GmbH. All rights reserved.