Biotic interactions in a Mediterranean oak forest: role of allelopathy along phenological development of woody species

Hazem Hashoum (1) , Mathieu Santonja (2, 1) , Thierry Gauquelin (1) , Arne Saatkamp (1) , Jordane Gavinet (1) , Stephane Greff (1) , Caroline Lecareux (1) , Catherine Fernandez (1) , Anne Bousquet-Mélou (1)

1 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
2 ECOBIO - Ecosystèmes, biodiversité, évolution [Rennes]

Plant–plant chemical interactions in forests can have a strong impact on the biodiversity and dynamics of these ecosystems, particularly in Mediterranean forests where plants exhibit a high secondary metabolite diversity. Allelopathic interactions in Mediterranean ecosystems have been mostly studied in the first stages of ecosystem dynamics, shrublands and pine forests, but little is known about these interactions in mature oak forests. In this study, the allelopathic effect of three main woody species of downy oak forests (Quercus pubescens, Acer monspessu-lanum and Cotinus coggygria) on germination and growth of two herbaceous species (Festuca ovina and Linum per-enne) was tested through aqueous extracts obtained from different leaf phenological stages (green, senescent and litter). The germination velocity of the two target species was inhibited by the aqueous extracts of senescent leaves from all the woody species. The growth of F. ovina seedlings was affected by aqueous extracts of green leaves of all the woody species, while the growth of L. perenne was only affected by aqueous extracts of green leaves of A. monspessulanum. This shows that (i) allelochemicals released by leaf leachates of the dominant woody species could control the dynamic of the herbaceous species, and then their potential competition with trees and (ii) allelo-pathic effects of woody species are related to their phenological stage and seem consistent with the development stage of target species.

Mots clés: Plant–plant interaction; Forest ecosystem; Allelopathy; Phenological stage

Domaines: Biodiversité et Ecologie; Interactions entre organismes

Hazem Hashoum, Mathieu Santonja, Thierry Gauquelin, Arne Saatkamp, Jordane Gavinet, et al.. Biotic interactions in a Mediterranean oak forest: role of allelopathy along phenological development of woody species. European Journal of Forest Research, 2017, 136 (4), pp.699-710. ⟨10.1007/s10342-017-1066-z⟩. ⟨hal-01756430⟩