The realised and potential soil seed bank in the Potentillo albae-Quercetum community in the Białowieża primeval forest

Abstract

Seedling emergence from soil seed bank was studied during 3 growing seasons 1997-1999 in: 1) 60 plots in 3 parts of the Potentillo albae-Quercetum patch: A - with Carpinus betulus (hornbeam) present only in the herb layer (canopy cover ca. 50-60%), B - after tree felling, at present with hornbeam dominating the shrub layer (cover >90%), C - invaded by hornbeam 30-40 years ago (cover ca. 90%), and in 2) 60 soil samples from objects A, B, C kept in an unheated glasshouse. The results suggest that the seed bank realised in natural conditions is poorer in species with high light requirements (the Ellenberg indicator values for light (L ≥ 6) and their seedlings in comparison with the potential seed bank estimated in glasshouse conditions (field: A - 24; B - 17; C - 7, glasshouse : 44; 38; 32 species / 2 m2, field: 321; 108; 14, glasshouse: 785; 1205; 177 seedlings / m2, respectively). Contrarily, more species and seedlings with moderate light demand (L = 3-5) appeared in the field plots (field: A - 26; B - 25, glasshouse: 20; 14 species / 2 m2. field: 1014; 310, glasshouse: 328; 71 seedlings / m2). The shading by hornbeam negatively influences the size of the seed bank (field: A - 1743; B - 1226: C -680, glasshouse: 1547; 3274; 459 seedlings / m2) and its species richness (field: A - 55; B - 48; C - 19, glasshouse: 76; 59; 56 taxa / 2 m2).