6533b851fe1ef96bd12a9eae

RESEARCH PRODUCT

Diversité fonctionnelle au sein des communautés de plantes adventices : effet de la rotation et du type de culture

subject

description

During this internship I investigated the effects of habitats i.e. field margin or the core of the field, and of crop sequences weed taxonomic and functional diversity in arable fields. We selected 75 fields from a database of flora surveys that have been conducted since 2005 in the area of Fénay. In the 75 fieds, the flora was sampled four consecutive years. The indices of Shannon-Weaver, Simpson and Pielou and species richness were selected for taxonomic study, while Rao's quadratic entropy and the community weighted mean (CWM) of the traits in the community were used for the functional study. Four functional traits were selected for the analyses. Our results showed that all studied factors did not have the same impact on weed community. Weed diversity was affected by the habitat but not by crop sequence. Weed community of the field margin was richer and more diverse than that of the core field. Considering the functional analysis, the values of specific leaf area (SLA; functional trait) were influenced by the habitat but did not vary with crop sequence. This is mainly due to the composition of weed communities in field margin which shelters perennials contrary to communities in the core field. The average height of plant in weed communities did not vary with the habitat even though it was shown to be variable in the core field. This is because canopy architecture differs between the two compartments suggesting different plant strategies. The habitat seems to have a major effect (compared to crop sequence) on weed species assembly in arable fields.