Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 88. (Budapest 1996)

Csontos, P., Horánszky, A. , Kalapos, T. ; Lőkös, L.: Seed bank of Pinus nigra plantations in dolomite rock grassland habitats, and its implications for restoring grassland vegetation

Species groups Nr of seedlings Average cover (%) Vincetoxicum hirundinaria 0.05 Viola reiche nbachiana 0.05 No. of species in the seed bank 13(9)* Total nr. of individuals 20(12) No. of seeds/sqm 66 (39.6) * Values in parentheses arc without Group "B" lutea arborescens, Filipendula vulgaris, Polygala amara, Teucriurn montanum and Viola rupestris. Because these species probably disappeared during the early stage of pine plantation development, their seed bank character can be considered as "long term persistent" according to THOMPSON'S method (THOMPSON 1993). Additional data are given by POSCHLOD etal. (1991) who rendered a persistent seed bank probable for Teucriurn montanum. With respect to Campanula sibirica seeds from deep soil layers of several samples taken from xerotherm grasslands were found germinable (A. SENDTKO, pers. comm.). It may be worth mentioning that the species of this group, with persistent seed bank are subordinated components of the dolomite rock grassland communities. A similar phenomenon is reported for the composition of the persistent seed bank of chalk grasslands (RYSER & GiGON 1985, GRAHAM & HUTCHINGS 1988, POSCHLOD et al. 1991). Group "N" - Members of native communities other than the rock grasslands. Out of the three species in this group those with wind dispersed seeds contributed most (Calamagrostis epigeios and Epilobium tetragonum). The additional Cardamine impatiens is a forest species, therefore it may have occasionally grown in the area since it was afforested or the seeds were introduced by zoochory. Group "W" - Weeds and alien neophytes. This group counts seven species of which 4 are wind dispersed: Conyza canadensis, Solidago canadensis, Sonchus asper, Taraxacum officinale. A further three species are common weeds of disturbed places. These presumably were introduced at the time of afforestation and may have been producing seeds for some subsequent years. Except Berteroa the other two may belong to the next "B" group as well. Group "B" - Species probably originated from the Botanical Garden. From the five species put here Poa annua and Stellaria media were frequent weeds in the greenhouse where the soil samples were placed. Mature specimens of Populus nigra cv. italica are found in the vicinity of the green house and penetration of their fluffy seeds through the air passages was observed. A similar origin is supposed for the further two Salicaceae species {Populus alba and Salix capraea). According to the main types of origin of seeds in the experiment 58.3% can be considered autochtonous, while 41.7% allochtonous. From the latter 66.6% of seeds were anemochorous.