Local and regional trends in the ground vegetation of beech forests

Arnault Lalanne (1) , Jacques Bardat (2) , Fouzia Lalanne-Amara (1) , Jean-François Ponge (1)

1 MAOAC - Mécanismes adaptatifs : des organismes aux communautés
2 OSEB - Origine, structure et évolution de la biodiversité

We sampled moss and vascular forest vegetation in five ancient beech forests from northwest France, embracing in each a wide array of environmental conditions. Indirect (PCA) and direct (RDA) gradient analysis were used to discern local and regional ecological factors which explain the observed variation in species composition. Our results point to a global factor encompassing a large array of soil and light conditions, unravelled when local particularities of studied forests are partialled out. The humus form, numerically expressed by the Humus Index, explains a large part of the observed variation in ground vegetation. Our study confirmed opposite trends in vascular and moss species richness according to humus condition. Ecological factors to which vascular and moss forest species respond at the regional level can be estimated directly on the field by visually inspecting humus forms and vegetation strata despite of the confounding influence of local factors.

Mots clés: beech forests; ground vegetation; Humus Index; regional and local factors; species groups; species richness

Domaines: Science des sols

Arnault Lalanne, Jacques Bardat, Fouzia Lalanne-Amara, Jean-François Ponge. Local and regional trends in the ground vegetation of beech forests. Flora, 2010, 205 (7), pp.484-498. ⟨10.1016/j.flora.2009.12.032⟩. ⟨hal-00504077⟩