SEED BANK CHARACTERISTICS OF DUTCH PLANT-COMMUNITIES

With the recent appearances of a new and well-documented classificatio n of the Dutch plant communities (Schaminee et al 1995a,b; 1996) and a database on the seed longevity of plant species of North West Europe (Thompson ct al. 1997a) it was possible to investigate patterns of see d longevity in Dutch plant communities, considering the frequencies of plant species in various communities. This study revealed that arable weed communities have long-lived seeds compared to the transient seed bank of deciduous woodland; species-rich grassland communities tend t o have a short-lived soil seed bank, intermediate between the latter t wo communities, Moreover, the present study showed that significant di fferences in community longevity exist between weed communities as wel l as between grassland communities. The approach based on soil seed ba nk spectra of plant communities gives support to existing phytosociolo gical theories on different strategies of plant communities sensu Stor telder (1992) and Schaminee & Stortelder (1996). The information on se ed longevity of communities is essential to the practice of nature con servation and nature development because it reveals the possible vulne rability of plant communities to extinction, including their soil seed banks, the necessity of their conservation and their possibilities fo r regeneration.