Vliv půdní semenné banky a semenného deště na vývoj vegetace poklesových kotlin Karvinska

Abstract

Soil seed bank, as a collection of viable seeds in the soil, is, together with seed rain, an important topic in the field of ecology. The transfer of new seeds and their preservation in the biotope enable plant species to colonize new places, to withstand unfavourable external conditions and thereby ensure survival of individual species and their genetic diversity. This study focuses on the assessment of the soil seed bank, determined by both cultivation and separation analysis at two different soil depths; seed rain, examined using funnel traps; above-ground vegetation, described using phytosociological relevés; and the impact of selected environmental variables on these phenomena in the environment of two subsidence basins – Kozinec and U cesty. The above-ground vegetation of selected subsidence basins is characterized by initial stands leading to floodplain forests, coastal reeds, but also to ruderal vegetation. Areas with higher chromium and arsenic concentration are characterized by the presence of metallophytes. The low similarity to the soil seed bank suggests that these are more stable habitats. Diversity of above-ground vegetation is also low, especially in the forest parts. The number of seeds in the soil decreases significantly with increasing depth - 64 % and 86 % of all seeds are in the upper soil layer (0-5.3 cm). Species diversity is lower in soil seed bank (0-5.3 cm) than in the above-ground vegetation and further decreases in the seed bank at a depth of 5.3-10 cm and seed rain. Even though the diversity and similarity with the above-ground vegetation in the soil seed bank determined by both methods is similar, they are characterized by a significantly different species composition, with their similarity reaching only 28 %. In the event of a sudden disturbance in area of interest, species determined by the cultivation method would prevail in the vegetation and would be gradually supplemented by species of separation method and seed rain, where woody species dominates. The dominance of woody species in the seed rain is impacted by relatively high seed trap setting, by which the study focuses on capturing seeds from surrounding areas. Autochory and less anemochory appear to be important dispersal methods. The representation of the Allium strategy is the most diverse in terms of species, but the most captured seeds belong to the Phragmites strategy.