title: Habitat filtering and niche differentiation jointly explain species relative abundance within grassland communities along fertility and disturbance gradients.
abstract: Deterministic niche-based processes have been proposed to explain species relative abundance within communities but lead to different predictions: habitat filtering (HF) predicts dominant species to exhibit similar traits while niche differentiation (ND) requires that species have dissimilar traits to coexist. Using a multiple trait-based approach, we evaluated the relative roles of HF and ND in determining species abundances in productive grasslands. Four dimensions of the functional niche of 12 co-occurring grass species were identified using 28 plant functional traits. Using this description of the species niche, we investigated patterns of functional similarity and dissimilarity and linked them to abundance in randomly assembled six-species communities subjected to fertilization/disturbance treatments. Our results suggest that HF and ND jointly determined species abundance by acting on contrasting niche dimensions. The effect of HF decreased relative to ND with increasing disturbance and decreasing fertilization. Dominant species exhibited similar traits in communities whereas dissimilarity favored the coexistence of rare species with dominants by decreasing inter-specific competition. This stabilizing effect on diversity was suggested by a negative relationship between species over-yielding and relative abundance. We discuss the importance of considering independent dimensions of functional niche to better understand species abundance and coexistence within communities.
authors.affiliation: INRA UR874 UREP, 234 Avenue du Brézet, F-63100, Clermont-Ferrand, France.|Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Vincent
authors.initials: V
authors.lastname: Maire
authors.affiliation: CEBC-CNRS (UPR 1934), 79360, Beauvoir sur Niort, France.|INRA, USC 1339, CEBC-CNRS, 79360, Beauvoir sur Niort, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gross
authors.affiliation: CEBC-CNRS (UPR 1934), 79360, Beauvoir sur Niort, France.|INRA, USC 1339, CEBC-CNRS, 79360, Beauvoir sur Niort, France.
authors.forename: Luca
authors.initials: L
authors.lastname: Börger
authors.affiliation: Max-Planck Institute for Biogeochemistry, D-07745, Jena, Germany.|Université du Québec à Trois-Rivières, CP 500, Trois-Rivières, Québec, Canada, G9A 5H7.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Proulx
authors.affiliation: Max-Planck Institute for Biogeochemistry, D-07745, Jena, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wirth
authors.affiliation: Agronomic Institute of Paraná, Ponta Grossa-PR, Brazil.
authors.forename: Laíse da Silveira
authors.initials: LDS
authors.lastname: Pontes
authors.affiliation: INRA UR874 UREP, 234 Avenue du Brézet, F-63100, Clermont-Ferrand, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Soussana
authors.affiliation: INRA UR874 UREP, 234 Avenue du Brézet, F-63100, Clermont-Ferrand, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Louault
mesh_terms: D044822:Biodiversity; D005298:Fertility; D005602:France; D006109:Poaceae / Q000254:growth & development* / Q000502:physiology*; D019655:Quantitative Trait, Heritable; D013045:Species Specificity