Variability of the soil seed banks in the natural deciduous forest in the białowieża national park

Abstract

Using the germination method, the species diversity, density of the soil seed bank and its relation to cover vegetation in a natural deciduous forest with primary and secondary tree stand were compared. It was found that the mean density and species composition of the soil seed bank in the forest with secondary tree stand that has spontaneously been overgrown over the last 90 years after clear-cutting does not differ from the soil seed bank derived from primeval forest (3167m-2 vs. 3827m-2). In both stands there were 46 species altogether and 36 were common and seed banks were dominated by herbs. The most abundant in this group were: Urtica dioica, Chrysosplenium alternifolium, Geranium robertianum, Oxalix acetosella. In both cases it was found that the species structure of the herb layer was similar to that of the seed bank in about 70%. The seed banks of species absent from the herb layer or present there only sporadically were much more abundant. The seedlings of these species constituted more than one third of all seedlings that emerged in the samples from the secondary tree stand and only 5% those from the primary one. The analysis of seed bank in heavily rooted places under primary and secondary tree stands showed that in places with a totally distroyed herb layer the density of the soil seed bank in primeval forest was three times lower than in places with fully developed herb layer structure (102.60±22.61 vs. 307.0±206.5 per sample). This difference under secondary tree stand turned out to be much lower (415.8±137.8 vs. 358.2±126.0 per sample).