Long-term seed bank dynamics in a temperate forest under conversion from coppice-with-standards to high forest management

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Abstract

Questions: How do changes in forest management, i.e. in disturbance type and frequency, influence species diversity, abundance and composition of the seed bank? How does the relationship between seed bank and vegetation change? What are the implications for seed bank dynamics?

Location: An ancient Quercus petraea — Carpinus betulus forest in conversion from coppice-with-standards to regular Quercus high forest near Montargis, France.

Methods: Seed bank and vegetation were sampled in six replicated stand types, forming a chronosequence along the conversion pathway. The stand types represented mid-successional stages of stands in transition from coppice-with-standards (to high forest (16 plots) and early- and mid-successional high forest stands (32 plots).

Results: Seed bank density and species richness decreased with time since last disturbance. Adjusting for seed density effects obscured species richness differences between stand types, but species of later seres were nested subsets of earlier seres, implying concomitant shifts in species richness and composition with time since disturbance. Later seres were characterized by species with low seed weight and high seed longevity. Seed banks of early seres were more similar to vegetation than to later seres.

Conclusions: Abandonment of the coppice-with-standards regime altered the seed bank characteristics, as well as its relationship with vegetation. Longer management cycles under high forest yield impoverished seed banks. For their persistence, seed bank species will increasingly rely on management of permanently open areas in the forest landscape. Thus, revegetation at the beginning of new high-forest cycles may increasingly depend on inflow from seed sources.

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