Impact des Ludwigia exotiques envahissantes sur les communautés végétales : existe-t-il un effet de la compétition ?

Brigitte Ruaux (1) , Jean-Pierre Berton (1) , Sabine Greulich (1) , Jacques J. Haury (2)

1 CITERES - Cités, Territoires, Environnement et Sociétés
2 ESE - Écologie et santé des écosystèmes

Two species of exotic Ludwigia have spread in France during the last century. Those amphiphytes typically build up dense and continuous stands with potentially strong impact on ecosystem functioning. This field study tests the impact of Ludwigia on the expression of the local pool of plant species comprised in the propagule bank. On three former channels of the middle Loire River, densities of Ludwigia stands have been manually reduced three times during a growing season (treatments 0% Ludwigia and 50% Ludwigia compared to untouched stands) while other species were preserved. Vegetation cover was monitored prior to each manipulation. Species richness was low in all former channels and treatments (Nmax = 9). It is not influenced by treatment. Significant differences in species abundances existed between treatments and sites, but no consistent pattern was detected that demonstrated a clear negative impact of Ludwigia on diversity of plant communities.

Mots clés: Ludwigia peploides; Ludwigia grandiflora; Plantes envahissantes; Amphiphytes

Domaines: Etudes de l'environnement

Brigitte Ruaux, Jean-Pierre Berton, Sabine Greulich, Jacques J. Haury. Impact des Ludwigia exotiques envahissantes sur les communautés végétales : existe-t-il un effet de la compétition ?. Quatrième colloque ECOVEG, Mar 2008, Rennes, France. pp.199-206. ⟨halshs-00358209⟩