Seed bank formation during early secondary succession in a temperate deciduous forest

1 Seed banks are dynamic entities, with input occurring through dispersal a nd loss occurring through germination and various sources of mortality. Mea sures of abundance of seeds in the soil at one point in time cannot disting uish those seeds destined to germinate or die in the next growing season fr om those entering the long-term seed bank, and cannot therefore reveal the proportion of seeds that are carried over from year to year. 2 We studied seed bank dynamics in a 2.5-ha deciduous forest gap by followi ng the fate of a single year's cohort of seeds over 2 years. Seed input for 1 year, subsequent in situ germination and survivorship were measured at 6 0 locations. We examined how temporal changes in seed bank composition were affected by the presence of the dominant gap colonizing species Rubus alle gheniensis. 3 Over the course of 2 years, both mean seed density and its variance decli ned. The temporal changes in density were not, however, accompanied by dete ctable changes in diversity. 4 Three species (R. allegheniensis, Phytolacca americana and Paulownia tome ntosa) dominated the seed bank. Seed bank accumulation patterns in Rubus an d Phytolacca showed contrasting responses to the presence of Rubus, with Ph ytolacca excluded from seed banks in such patches through reduced input and increased mortality. 5 First year germination and post-dispersal mortality interact with seed in put to influence the spatial distribution of density and diversity in the l ong-term seed bank. Substantial long-term seed banks do form within tempera te forest gaps and patterns of above-ground vegetation can have substantial effects on their dynamics.