title: Assessing long-term effects of multiple, potentially confounded drivers in ecosystems from species traits.
abstract: Although species traits have the potential to disentangle long-term effects of multiple, potentially confounded drivers in ecosystems, this issue has received very little attention in the literature. We aimed at filling this gap by assessing the relative effects of hydroclimatic and water quality factors on the trait composition of invertebrate assemblages over 30 years in the Middle Loire River (France). Using a priori predictions on the long-term variation of trait-based adaptations over the three decades, we evaluated the ability of invertebrate traits to indicate the effects of warming, discharge reduction and water quality improvement. Hydroclimatic and water quality factors contributed to up to 65% of the variation in trait composition. More than 70% of the initial trait response predictions made according to observed long-term hydroclimatic changes were confirmed. They supported a general climate-induced trend involving adapted resistance and resilience strategies. A partial confounding effect of water quality improvement acting on trophic processes was also highlighted, indicating that improved water quality management can significantly help to reduce some adverse effects of climate change. This trait-based approach can have wider implications for investigating long-term changes driven by multiple, potentially confounded factors, as frequently encountered in the context of global change.
authors.affiliation: Irstea, UR MALY, Milieux Aquatiques, Ecologie et Pollutions, 5 rue de la Doua, 69626, Villeurbanne, CS70077, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Floury
authors.affiliation: CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux, Université de Lorraine, Campus Bridoux, Rue du Général Delestraint, 57070, Metz, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Usseglio-Polatera
authors.affiliation: EDF R&D, Laboratoire National Hydraulique et Environnement, 6 Quai Watier, BP 49, 78401, Chatou, France.
authors.forename: Cecile
authors.initials: C
authors.lastname: Delattre
authors.affiliation: Irstea, UR MALY, Milieux Aquatiques, Ecologie et Pollutions, 5 rue de la Doua, 69626, Villeurbanne, CS70077, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Souchon
mesh_terms: D000818:Animals; D057231:Climate Change; D017753:Ecosystem; D005602:France; D007448:Invertebrates; D011157:Population Dynamics; D045483:Rivers; D013997:Time Factors
keywords: climate change; confounding effect; invertebrates; large rivers; long-term trends; multiple drivers; species traits; water quality