Seed banks are of vital importance for local plant persistence and recruitment, for maintaining both plant and genetic diversity and for habitat restoration. Yet, seed-bank dynamics, particularly on the long term and in deciduous forests, remain poorly understood. Additionally, information on compositional seed-bank differences under contrasting tree canopies remains scarce. This study aims at quantifying long-term seed-bank dynamics by sampling vegetation and seed banks along a four-stage successional chronosequence (40, 80, 120 and 250 years) using 12 10 m x 10 m plots per forest stand age-class under fully developed oak-hornbeam and beech canopies. Seed banks were remarkably abundant and diverse. Species richness and seed density declined steeply with forest stand age, regardless of canopy species. Seed-bank composition differed significantly with stand age, yet also with tree species. Most likely, tree species-dependent ecosystem engineer effects on light availability and possibly also litter quality affect the seed bank through the vegetation. Compositional differences between seed banks from stands with a different canopy diminished with increasing stand age, possibly due to a gradual loss of species with a less persistent seed bank. Long-term seed-bank dynamics in deciduous forests seem to consist predominantly of a unidirectional and predictable depletion of the seed bank as long as large disturbances, which would allow seed-bank replenishment of early-successional species, are lacking. Furthermore, forest seed-banks appear to converge upon a characteristic seed bank in the later stages of forest development, irrespective of canopy composition, driven by seed-bank depletion and limited input from the herb layer. (C) 2010 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.
|Journal||Perspectives in Plant Ecology Evolution and Systematics|
|Number of pages||8|
|Publication status||Published - 2010|