Resumen de Seed banks of managed and degraded grasslands in the Krkonoše Mts., Czech Republic
Viola Handlová, Zuzana Münzbergová
Grassland seed banks are traditionally considered a source of new species in degraded communities. However, many recent studies have shown that the potential of the seed bank to restore many communities is rather limited. Two principal reasons for these limitations, loss of species from the seed bank or inability of the species to create any seed bank, are, however, usually not distinguished.
This study aims to assess the role of seed bank composition and heterogeneity in the restoration of species-rich plant communities. It was carried out in mountain grasslands in the eastern part of the Krkonoše Mountains, Czech Republic. The composition of vegetation and seed bank were recorded and their relationship was assessedin 1.5m × 1.5 m plots placed in non-degraded and degraded parts of seven grasslands. Vegetation at currently managed sites is not degraded; degraded parts were without management (dominated byHolcus mollis, Bistorta major orRumex alpinus). The degree of heterogeneity of seed bank and vegetation was tested as the relationship between subplot similarity, distance, and degradation stage.
Degradation had significant effects on composition of both aboveground vegetation and seed bank and increased heterogeneity both in the vegetation and in the seed bank. Species absent from the vegetation of degraded plots were also absent from the seed bank of both degraded and non-degraded plots, indicating that the absence of species from the seed bank is not due to their loss during the degradation process but rather due to the low number of seeds in the seed bank already in the non-degraded communities. Furthermore, the seed bank of the degraded communities largely results from the present vegetation of these communities. This supports the limited role of the seed bank in these communities. Restoration of these sites is thus impossible unless management will include methods with which seeds will arrive at the degraded sites.
