Marc Veyrat

I-Real Contre Creeper

Zombie

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

qu'une carte peut être changée, le / la joue® peut soit conserver les cartes qu'il possède soit échanger une carte, soit décider de même changer toutes ses cartes puisqu'il a obtenu le chiffre 6 sur le premier dé. Si par bonheur, avec le second dé il a obtenu la lettre A, il peut enclencher l'IA. Celle-ci est susceptible de décrypter les cartes et les connexions entre les mots / images. Si l'IA peut répondre, le / la joue® reste bloqué.e et ne peut faire avancer la personne spectre / acteur.trice dans le labyrinthe en VR : le but ultime étant d'y délivrer une des trois princesses prisonnières… Comme le souligne Laurence Devillers -Chercheuse au LIMSI / CNRS, Professeure d'informatique à l'Université Paris -Sorbonne et spécialiste des interactions hommes / machines -sur France Culture,4 "les avancées majeures en terme de développement d'intelligences artificielles doivent désormais implémenter l'intelligence entre les mots, ce qui n'est pas dit par leur stricte signification encyclopédique"… Cette installation hypermédia (même en étant conçue et en restant avant tout une oeuvre artistique) a pour but scientifique de permettre de découvrir si une machine est capable de penser les connexions entre les mots, finalement le JE(U) conceptuel de la langue -et en particulier toute la richesse du français -qui permet à ce JE sujet de Nous5 tous, en nous exprimant, de faire référence en somme sans la citer explicitement.

Chacun connaît cet épisode célèbre de la vie d'OEdipe : arrivant près de la ville de Thèbes, il rencontre le Sphinx qui lui pose une énigme… Le test est dangereux car non seulement il risque sa vie, mais toute son humanité, son appartenance au Nous. Ce JE(U) / oeuvre hypermédia est donc également, en quelque sorte, un test laboratoire… Que reste-il de ce Nous en JE(U en par rapport à l'Intelligence Artificielle ?+( Et, en revanche, que peut vraiment comprendre l'IA de ce Nous tous interconnecté par le langage ?+) Et peut-elle s'émanciper -à terme, comme Nous -du JE(U) ?+) Avec i-REAL, chaque joue® inverse le dispositif du Sphinx -qui possède le buste d'une femme sur un corps de lion -pour ®-METTRE en JE(U) ce qu'il lui reste de sa nature humaine et animale, face aux machines qui passent et voyagent devant Nous. La métaphore peut est intéressante : à la fin de la saison 1 de Westworld,6 les androïdes, appelés hôtes dans le parc de JE(U) futuriste, émergent de la forêt telle une horde de sauvages habillés de peaux de bêtes et de masques. Ils annoncent de façon prémonitoire leur soulèvement… La question de La Fabrique des Histoires, telle qu'elle a été proposée à chacun des intervenants de ce colloque, serait susceptible de ®-ENVOYER ce chacun d'entre Nous paître à la marge des scénarios qui lui suggèrent de ®-PENSER ses relations à une prétendue conscience naturelle… Comment celle-ci se manifeste en acte ?+) Prend forme dans nos choix, dans notre corps ?+) En somme indique-t-elle le résultat d'une cartographie et sous-entend-t-elle -si il y a lieu -un dispositif de perspective mentale qui distinguerait ce Nous humain / animal de la machine à travers un écart manifeste ?+) Ou plutôt comment pourrait-elle faire pour que JE puisse en prendre conscience ?+) À cet égard, le titre du dernier épisode de cette première saison de Westworld : The Bicameral Mind (-! L'Esprit Bicaméral !-) n'est pas anodin. Est-ce que ce Nous est capable de se diriger in/consciemment sur un territoire ; c'est-à-dire à travers une ®-LECTURE de cette Histoire qui nécessiterait d'abord de notre part une prise de conscience de la mise en ordre, non pas seulement autour d'un concept de ce territoire, mais ®-ACTIVE à cette errance consciente, dans cette construction mentale ?+) Julian Jaynes (-! psychologue à l'origine de cette théorie controversée !-) évoque cette i+M/POSSIBILITÉ à travers L'Iliade : l'homme n'avait pas conscience de sa conscience du monde.7 i+D-S_02 : Société i Matériel, T i-REAL-21 château CREEPER, MINECRAFT, 2018 1/ i-REAL &-( )-! contre ?-( )-! Zombie Boys Afin de pouvoir prendre conscience de sa conscience du monde, JE doit peut-être alors se faire aider par des créatures fantastiques, des DOUBLE U-® plus ou moins anthropomorphes qui lui parlent de l'intérieur du JE(U), entre JE et MOI ?+) Et c'est effectivement ce qui se passe dans le dernier épisode avec cette première saison de Westworld. Puisque les hôtes (-! Du moins ceux de la première génération !-) sont censés entendre leur propre programme comme une voix intérieure pour acquérir un niveau de conscience supérieure. Dolorès est l'un.e d'eux. Pour objectiver cette question, comprendre qui il / elle est, il lui faut, comme pour les autres, ®-TROUVER le centre du labyrinthe et découvrir où se cache Wyatt !+) Métaphore de cette prise de conscience / prise de contrôle de la relation JE-MOI / libération (-! véritable i+D/signe 8 !-) ce centre hypothétique ®-PRÉSENTE littéralement un homme qui se prend la tête !-) Où est Wyatt puisqu'il n'est que la DOUBLE U-® masculine d'elle-même, Dolorès, responsable sur l'ordre de Arnold du massacre des premiers hôtes ?+)… Où est Wyatt demande l'homme en noir / lui-même DOUBLE U-® de William, autrefois incrédule visiteur du parc et amoureux transi de Dolorès, mais devenu progressivement son tortionnaire et actionnaire majoritaire de la société possédant désormais… ce même parc... Lorsque Dolorès se rencontre en Wyatt et donc prend conscience de cet autre hôte en elle et par là même de la conscience de l'absurdité de cet Autre hôte en elle, elle peut enfin se libérer de ce qui concernait le niveau basique de son programme, la forme vitale de ritournelle qui constituait sa boucle temporelle en lui permettant de ®JOUER encore et encore SON rôle à l'identique, SON sisyphe heureux. Or ce monde, SON monde appartient dorénavant à Ce[LUi] qui arrive, Wyatt, UN sisyphe heuristique... En quelque sorte un "bug", 9 Ce[LUi] qui va exiger d'elle une ®-PRISE de conscience. Albert Camus Nous invite à comprendre l'i+D d'un nécessaire consentement à l'absurde de notre vie, cette rencontre avec le bug indice / pensable qui exigerait de tout notre Nous, afin de pouvoir vivre sans désespoir, de sans cesse en ®-PRENDRE conscience. Voire de ®-METTRE continuellement en cause cette i+D comme nécessaire, pour lui permettre d'exister en MOI, en tant que refuge étalon, en dehors de ce Nous tous social… Albert Camus écrit déjà en 1942 dans Le Mythe de Sisyphe : "Il arrive que les décors s'écroulent. Lever, tramway, quatre heures de bureau ou d'usine, repas, tramway, quatre heures de travail, repas, sommeil et lundi mardi mercredi jeudi vendredi et samedi sur le même rythme, cette route se suit aisément la plupart du temps. Un jour seulement, le pourquoi s'élève et tout commence dans cette lassitude teintée d'étonnement. Commence, ceci est important. La lassitude est à la fin des actes d'une vie machinale, mais elle inaugure en même temps le mouvement de la conscience". Albert Camus, Le Mythe de Sisyphe, in OEuvres complètes, tome 1, Collection Bibliothèque de la Pléiade, nrf, 2006, Éditions Gallimard, Paris, p.227. Tous les termes en italiques sont entre guillemets dans le texte d'origine.

Et ce test d'empathie dans Westworld se révèle à Dolorès sous la forme d'une célèbre fresque de Michel Ange : La Création d'Adam. Encore une question d'Art, d'artiste et de spectateur.trice. Ainsi, dans le Désert de Retz, inutile de tourner éternellement autour de la Colonne détruite, fabrique imaginée en ruine, puisque métaphore de cette i+M/POSSIBLE conscience i-MÉDIA de ce monde qui nous entoure, point focal obstruant l'horizon de la conscience. "C'est ce phénomène d'horizon que Giordano Bruno analyse en évoquant, dans un célèbre passage du De immenso et innumerabilibus (1591), un souvenir d'enfance : Je croyais, écrit-il, qu'il n'y avait plus rien au-delà du Vésuve, car il m'était impossible d'apercevoir quelque chose par-delà. L'horizon semble enclore dans son confinement circulaire le monde perçu", écrit Jean Seidengart 10 qui ajoute : "pourtant, nos déplacements nous font franchir cette limite, qui n'a donc pas d'existence absolue. Il n'y a pas d'horizon en soi, mais toujours pour un observateur : c'est d'une certaine façon le corrélat de la limitation des sens". Avec Michel Ange, ce franchissement de la limite se cristallise au travers de cette crispation de l'avant-bras -apparemment langoureux et provoqué par Adam -toutefois en nous laissant constamment soupçonner une forme de dépliement ®-TENU en tension, attirant notre regard vers les extrémités, un i+M/POSSIBLE toucher du doigt. En communication visuelle, si "tout doit communiquer sans résistance, sans relégation, dans un hyper-espace fluide et acosmique" 11 … écrit Gilles Lipovetsky dans L'ère 8 "Un i+D/signe est un schéma conceptuel proposé sous forme d'image. C'est l'organisation d'un ensemble de concepts reliés sémantiquement entre eux dans une forme plastique, qui a pour but d'exposer de façon structurée toutes les données, les liens et les connexions utilisés sur différents niveaux de langage d'un système d'information". Marc Veyrat, i+D/signe, Notion n°51, in 100 Notions pour l'Art Numérique, sous la direction de Marc Veyrat, Collection 100 Notions dirigée par Ghislaine Azémard, Éditions de l'Immatériel, livre hybride adossé à la plateforme www.100notions.com, Paris, 2015, p.136-138. 9 "Bug est un mot anglais signifiant insecte et désignant couramment tout type de dysfonctionnement. À la fois erreur et parasite, une telle ambiguïté plaît aux artistes qui jouent de l'accident et du hasard pour révéler des formes hybrides, imprévisibles et inattendues. En art numérique, le bug perturbe pour mélanger, désactiver, réactiver, obligeant à une mobilité de la création et de la pensée". Carole Brandon, Bug, Notion n°16, in 100 Notions pour l'Art Numérique, sous la direction de Marc Veyrat, Collection 100 Notions dirigée par Ghislaine Azémard, Éditions de l'Immatériel, livre hybride adossé à la plateforme www.100notions.com, Paris, 2015, p.48-50. 10 https://www.universalis.fr/encyclopedie/giordano-bruno/2-l-infinitisation-de-l-univers/ 11 Gilles Lipovetsky, L'ère du vide, Éditions Gallimard, Collection Folio / Essais, 1983, p.33., du vide, Michel Ange entraîne notre regard vers un surgissement du bug, un danger inévitable mais in/visible, c'est-à dire posté au seuil du visible de cette main prolongeant cet avant bras qui n'est pas au bout de son dépliement. Encore dans un potentiel à venir. Un ®-SURGISSEMENT de la conscience par la main de l'Autre MOI. Evidemment pour William, ce ®-SURGISSEMENT à travers Dolorès d'une conscience de l'Autre en MOI, [START_REF]Le Rythme du Serpent Observons cette carte spécialement associée à l'univers graphique du colloque… Afin d'ENTRE/VOIR Les Fabriques des Histoires comme une question de cartographie ?+) Evidemment, le premier coeur à gauche[END_REF] L'@-MORAL et l'i-MORAL permettent alors à chacun d'entre Nous de ®-METTRE au / en JE(U) un JE étouffé, essoufflé par la morale. Un JE de plus en plus pré-occupant, suppurant d'informations et d'ordre, parce que définitivement condamné à finir exposé à ce Nous fantasmé, parce que pré-occupé à réguler son écart à MOI dans l'i+D d'être un gardien du Nous social. Donc dans une dichotomie perpétuelle : toujours ce même combat i-MORAL schizophrénique contre ce ®-ÉTABLISSEMENT de l'ordre > < morale (-! d'ailleurs curieusement, ou plutôt furieusement exprimé, déjà par le général Mac-Mahon dans son discours du 28 avril 1873 après avoir réprimé dans le sang la Commune de Paris ?-) Ainsi, pour SUR/VIVRE, il semble urgent, nécessaire de se perdre sans Nous (-! voire se perdre peut-être contre Nous !-) par un JE en JE(U) ou encore mieux, perdre malgré la carte, continuellement garante de cette possible ®-MISE en ordre.

Outre Zombie Boy, il existe dans MINECRAFT plusieurs autres personnage particulièrement craquants côté @-MORAL. Car si "les zombies sont les créatures hostiles les plus courantes (-! et aussi les plus courantes de toutes les créatures !-) qui apparaissent dans les endroits sombres ou mal éclairés… Les Creepers sont des créatures humanoïdes ayant la peau verte parsemée de points gris, avec quatre jambes et aucun bras. Cela est dû au fait qu'ils soient basés sur un modèle de cochon raté par Notch". 16 i-REAL anticiperait peut-être notre rencontre avec ce cochon raté et serait donc le présupposé essentiel à tout projet non seulement vers / avec l'Autre mais avec ce MOI détaché, éparpillé sur / à travers les cartes d'un JE iN/CONSCIENT. "Markus Alexej Persson est plus communément connu sous le nom de Notch, créateur de MINECRAFT. C'est aussi l'un des fondateurs de Mojang AB". 17 22 "Reproduction, recréation, réinterprétation : le ®≠MAKE est à l'origine du réseau, jouant sur la répétition pour transfigurer ce qui sera de nouveau ®-interprété. Réutilisable, exploitable à l'infini par ses qualités propres d'objet numérique, l'oeuvre inclut désormais sa dissémination et sa réappropriation". Marc Veyrat, ®≠MAKE, Notion n°63, in 100 Notions pour l'Art Numérique, sous la direction de Marc Veyrat, Collection 100 Notions dirigée par Ghislaine Azémard, Éditions de l'Immatériel, livre hybride adossé à la plateforme www.100notions.com, Paris, 2015, p.164-166. extérieur qui le fait avancer !-) et l'immersion de Ce [LUi] qui nous ®-GARDE (-! Autre de ce géomètre maître nageur BUG-i BOY qui trace et compose l'avancée, tente de comprendre tout en voyant bien ce que l'Autre -invité -voit sans jamais vraiment pouvoir l'expérimenter !-) Avec cette esthétique de la frustration nous ®-PRODUISONS en i-REAL un processus de validité phénoménologique transcendantale. Edmund Husserl -cité, utilisé par Dylan Trigg encore -le définit ainsi : "lorsque l'autre meurt (-! Ce[LUi] que nous ne voyons : le géomètre !-), une certaine unité (-! Ce[LUi] qui nous ®-GARDE tel un cow-boy solitaire !-) ne se maintient que dans la mesure où l'unité par re-souvenir traverse ma vie -je vis encore et par le pouvoir de cette répétition, je peux en effet maintenir la présence du nous". 23 Cow-boy aveuglé par le casque VR, JE ®-GARDE Ce[LUi] que nous ne voyons : le géomètre… Bientôt se délectant de l'affrontement avec une IA. MINECRAFT : le premier plaisir consistant à construire des labyrinthes, l'en JE(U) est d'en perdre le fil, risquer la démesure ou la chute. Et puis il y a tous les bruits de pas de ces choses anticipées aléatoirement qui, a l'instar des bugs -voire la nation fantôme dans Westworld -viennent perturber ces mondes patiemment construits pour durer. Mais qui préfigurent aussi leurs propres ruines à travers notre JE(U) : nos errances, nos interrelations (-! plus ou moins !-) volontaires… au programme. Cette construction test MINECRAFT était donc l'occasion rêvée -dans une certaine mesure -de comprendre comment avancer, revenir en arrière, monter, descendre, sans cesse changer de points de vue, sous le regard (-! plus ou moins !-) BIENveillant de ces BUG-i BOYs.

  finalement cet Autre JE (-! le monstrueux homme en noir que l'on pourrait qualifier de non humain qui parle pour MOI !-) par l'appréhension d'un androïde de son propre dédoublement conscient est particulièrement perturbateur. Car s'agite ici une double schizophrénie miroir de deux observateurs d'un MOI postés à l'extérieur de JE primitifs 13 plongés à l'intérieur du JE(U). Dans cette question de La Fabrique des Histoires, il est donc essentiel de concevoir l'ensemble du Désert comme métaphore du labyrinthe et expérience de la conscience. Sans observation préalable se laisser aller au JE(U), passer par ici et à nouveau passer par là afin de Se ®-VOIR voir sans soupçonner avoir la maîtrise d'un ÇA-VOIR de l'Autre, sous peine de rester enfermé dans le jardin. Tourner le dos à la La Colonne détruite. Glisser, déraper de l'UN (-! JE unique !-) à l'AUTRE (-! JE en MOI !-) afin de définir chacun notre chemin dans le JE(U)… Pour i-DOUTER et donc imaginer le lancement d'un nouveau scénario… 14 i+D-S_03 : Société i Matériel, Labyrinthe Westworld, 2018 2/ i-REAL &-( )-! contre ?-( )-! CREEPER Un autre élément fondamental dans cette quête du JE est le rapport viscéral à la carte. Dans Westworld, celle en relief occupe évidemment une position clé à l'intérieur des salles de contrôle. Tout autour du plateau de JE(U) les techniciens et ingénieurs qui veillent au bon fonctionnement de l'ensemble, ®-GARDANT les androïdes dans leurs boucles narratives, deviennent des démiurges, finalement non seulement pour ces hôtes mais également pour les visiteurs qui deviennent eux-mêmes une PART-i du programme. Finalement la distinction entre hôtes et visiteurs n'est pas si i+M/PORTANTE que cela. L'i+D résidant dans le fait de se construire en réseau avec l'Autre -à travers une ®-SEMBLANCE -en éprouvant le parc de JE(U). Cet Autre se manifeste, à travers JE déjà en MOI de deux façons complémentaires : dans un corps i-MORAL et @-MORAL. Il faut entendre avec i-MORAL l'i+D que notre JE -singulier -éprouve et consomme l'information à travers son corps de manière unique. Il perturbe, bouscule ou interroge ainsi sans cesse la morale d'un Nous vu apparemment comme un ensemble indice / sociable cohérent et uniforme. L'@-MORAL, avec la lettre arobase utilisée en dehors de sa stricte signification dans l'aire anglo-saxonne, hispanique et lusophone ®-PREND ici le tracé spiralé d'un i+D/signe se référent au monde animal. L'@-MORAL, comme le souligne Dylan Trigg, est "antérieur à l'identité personnelle", 15 il nécessite donc de perdre notre volonté de s'accrocher indéfiniment à une quelconque morale préexistante volant en éclat devant cette singularité du JE comme de SE perdre dans un hors humain.

  En vendant ses actifs à Microsoft en 2014, il déclare à cette occasion qu'il refuse d'être un modèle. D'une certaine façon une forme d'ordre, une présence agissante qui parle pour l'Autre ou pour chacun d'entre Nous. In fine JE ne se ®-CONNAÎT plus )-? O-H et MOI qui suit JE ?-( et surtout en ce qu'est devenu Notch… Qui porte toujours un chapeau noir emblématique et s'apparente alors un personnage légendaire. Notch ®-PRÉSENTE finalement l'allégorie d'une IA avec tout ce que JE considère au jour du i (-! dans une société où tout est devenu bon dans l'information !-) comme un des dangers potentiels majeurs ; une icône assujettie à la réussite d'un programme qui a échappée à son créateur et reste désormais terrée, enfouie dans les méandres du JE(U).L'absurde, écrit Albert Camus, c'est "le refus continuel […] et l'insatisfaction consciente". 18 C'est elle qui pousse Markus Persson en JE iN/CONSCIENT à vendre son JE(U) : Creeper la DOUBLE U-® doit rester un cochon raté pour nous ®-PLONGER sans cesse dans cette nécessaire forme d'insatisfaction consciente. Et c'est aussi pour cette raison que l'esthétique MINECRAFT convient parfaitement à ce premier test JE(U) i-REAL > < IA. En utilisant des blocs (-! une allégorie du rapport distancié entre i-RÉEL > < PIXEL !-) afin d'exprimer un rapport mesuré à la 3D, en restant dans ce que nomme Carole Brandon, un ENTRE [CORPS/MACHINE], 19 les modules i-REAL -littéralement ici ces fictions flottantes 20 -ralentissent notre capacité à i-CROIRE, à croire au JE(U). Car dans i-REAL, il n'y a pas de temps. Il est suspendu à la manière élastique dont chacun ®JOUE l'eSPACE, s'empare du programme. Carole Brandon écrit en résumé de sa thèse : "La compréhension de cette organisation spatiale et la conception orientale des espaces-temps semblent un moyen d'envisager cet entre corps/machine comme espace de résistance. Surtout, il favoriserait la compréhension de notre place dans le monde pour agir sur le monde". 21 16 https://minecraft-fr.gamepedia.com/Creeper 17 https://minecraft-fr.gamepedia.com/Markus_Persson Markus Persson a quitté Mojang le 5 novembre 2014 avec les autres fondateurs. Il écrit "Dès que cet accord sera finalisé, je quitterai Mojang et recommencerai à faire Ludum Dares et de petites expériences web. Si jamais je fais accidentellement quelque chose qui semble gagner du terrain, je vais probablement l'abandonner immédiatement".18 Commenté par André Comte-Sponville, L'absurde, de la révolte à la sagesse, in Philosophie Magazine, Hors-Série n°17, Albert Camus, La pensée révoltée, avril -mai 2013, p.15.19 Carole Brandon, L'ENTRE [CORPS/MACHINE], La Princesse & son MAC, thèse en Art et Sciences de l'Art, soutenue en 2016 sous la direction de Françoise Parfait, Laboratoire ACTE, Université Paris 1 Panthéon -Sorbonne : "C'est grâce à un conte, celui d'une Princesse et son Mac, écrit avec le réseau social Facebook pendant trois ans que nous voyagerons à travers ce que ces personnages représentent dans la zone instable et mobile de leurs rencontres. La Princesse et son Mac désigne un personnage de fiction, un corps réel et des machines. La Princesse ouvre sur un point de vue féminin, jouant un devenir. Le Mac renvoie autant à la marque Apple qui vend des ordinateurs Macintosh qu'à l'abréviation argotique française. Nous tenterons de poser l'hypothèse que l'art semble matérialiser des espaces particuliers, entre corps et machines. Ce titre L'Entre [corps/machine] caractérise ces espaces que nous nommons flottants, en référence au moucharabieh et au Ma Japonais. La compréhension de cette organisation spatiale et la conception orientale des espaces-temps semblent un moyen d'envisager cet entre corps/machine comme espace de résistance. Surtout, il favoriserait la compréhension de notre place dans le monde pour agir sur le monde. À partir d'une pratique artistique personnelle nous interrogerons les nécessités d'espaces flottants et en extension. Seules nos présences entre corps et machine rendent visible les liens relationnels « entre » les informations et les trajets opérés, « entre » nos corps et nos identités. Cette recherche s'attache à montrer que la force des réseaux sociaux, dans ma pratique artistique accompagne et génère les variabilités du corps et de nos perceptions en temps réel. L'entre [corps/machine] rend possible, selon les rythmes qu'il produit, des temps d'imprégnation et de rencontres dans lesquels nous puisons maintenant des forces vitales" : https://www.univ-smb.fr/2016/05/19/la-princesse-et-son-mac-une-performance-artistique-realisee-par-une-chercheure-du-llseti/ 20 Ad Ibidem 19 . 21 Ibid 19 . D'ailleurs, dans la série Westworld, comment i-CROIRE ?+) Afin que les visiteurs puissent raisonnablement ®-ENTRER dans le JE(U) les androïdes leur i+M/POSENT une distance. Ils sont les seuls (-! apparemment jusqu'à la fin de la saison 1 !-) à pouvoir mourir. Cette clef phénoménologique, par cette i+M/COMPLÉTUDE -cette complétude seulement apportée par l'information éprouvée de cette distance -ouvre la porte aux visiteurs. Elle leur permet de plonger sans crainte dans le JE(U). JE -visiteur transcendé -ne voit l'Autre -hôte esclave -qu'avec iN/DIFFÉRENCE, un écart qui ®-ENVOIT l'Autre toujours en dehors de MOI, vers un ailleurs que JE ne veut pas ®-CONNAÎTRE, voir ou savoir… En mourant, il demeure derrière la frontière, puisque -entre Nous -mourir dans un JE(U) n'est humainement pas acceptable ?+( L'hôte n'a pas le choix. Il doit endosser le rôle du LOOSE-®, de l'ÉTRANGE-®, celui qui l'empêche finalement d'être une menace pour un Nous sociabilisé et politiquement correct… Seulement en dehors du JE(U). Ainsi cette menace sourde d'un grand ®-EMPLACEMENT (-! Un hypothétique remplacement par un ®≠MAKE 22 humanoïde !-) ne DOIT jAMAIS pouvoir être en-visagée. L'hôte DOIT TOUJOURS rester à sa place, sa place de cochon raté. i+D-S_04 : Société i Matériel, Cartographie i-REAL, premier cercle, 2018 3/ i-REAL e-N i-MIGRANT A l'instar de la topologie cartographique d'un Westworld tournoyant autour d'un axe allégorique, la carte i-REAL s'enroule autour d'une anamorphose de la Méditerranée, lieu bien connu de toutes les perditions, y compris contemporaines. Composée de trois plateaux circulaires (-! Merci Pirates des Caraïbes !-) emboîtés les uns dans les autres. C'est l'élément central qui va permettre le double JE(U) i-REAL. Un JE(U) viral finalement, qui fait basculer notre Nous entre Ce[LUi] que nous ne voyons (-! Autre de ce cow-boy solitaire à la LUCK-i L-O+O-K, immergé dans un casque VR qui ne voit pas plus où il avance que cet Autre -hôte -

  Cette oeuvre hypermédia i-REAL, à travers l'ensemble du dispositif -IA + JE(U) de plateau / cartes INSTAGRAM > < séquences VR -nous obligerait ainsi à ®-DISSOCIER ce JE qui pense à MOI, avançant i-MOBILE devant le plateau + IA, en le confrontant sans cesse à ce devenir MOI d'un Autre ailleurs dans la VR : JE prisonnier d'une avancée mais aveugle d'un MOI souterrain, sous contrôle. Double entité miroir d'un JE-MOI imbriqué sur un entre / deux terrains -perpétuellement en ®-CONNEXIONen équilibre instable dans un entre / deux [CORPS/MACHINE], pour ®-PRENDRE la formule de Carole Brandon. Et puis il y a LA carte et LES cartes. Cette provocation de la ®-CONNEXION à l'Histoire se fabrique également contre l'IA à travers LES cartes et avec LES cartes contre LE plateau de JE(U)… À ce propos nous pourrions ®-LEVER ici des similitudes anthropologiques entre la manière d'éprouver, de ®-LIRE La Colonne Détruite comme d'aborder physiquement, rencontrer ce lieu abstrait de LA carte ?+) Car, dans le Désert de Retz, cette fausse ruine en forme de colonne tronquée nous suggère immédiatement, par sa présence, sa taille et son i+M/COMPLÉTUDE, un au-delà du paysage ®-PRÉSENTÉ. i+D-S_05 : Société i Matériel, Carte i-REAL, i-STORY-04_INSTAGRAM_18-04-02_numéro-00097 ®≠MAKE tableau Pinterest https://www.pinterest.fr/marcveyrat1/i-real-instagram-i_story/ 2018 23 Ibid 15 p.35.

En collaboration avec la société XRsperience https://youtu.be/hc66tjCGC9Q : l'ensemble du dispositif est susceptible d'être exposé dans un dôme dédié, mobile, car facilement démontable et transportable dans d'autres lieux.

https://www.instagram.com/marcveyrat/

Toutes les cartes i-REAL déjà disponibles sur https://www.pinterest.fr/marcveyrat1/i-real-instagram-i_story/

https://www.franceculture.fr/personne-laurence-devillers

Ce Nous d'un Nous tous contient notre JE sujet qui parle en s'écartant de son Moi, forcément en le régulant, comme la PART-i intrisèque d'un corps social qui, en s'exprimant, tente de lui échapper.

Série télévisée américaine diffusée sur HBO depuis 2016, créée par Jonathan Nolan (-! frère de Christopher Nolan !-) & Lisa Joy. ®≠MAKE du film Mondwest, Michael Chrichton, 1973.

Julian Jaynes, La naissance de la conscience dans l'effondrement de l'esprit, PUF, Paris, 1994, p.

Car in fine Wyatt se poste à mi-chemin des consciences respectives de Dolores, portant le pantalon et William affirmant son rôle d'homme, de vrai cowboy à travers une hyper masculinité, trop binaire pour être vraie afin d'oublier son côté féminin disparu… Avec toute la naïveté et les errements de sa jeunesse.

Un JE pensait encore radicalement s'exprimer pour MOI.

En faisant référence ici à l'analyse d'Ava dans Ex Machina, un double protocole miroir… ®-VOIR i-REAL La Politique du Visage / Enfermé.e avec un coyote / Rennes 2018.

Dylan Trigg, The Thing, Éditions MF, Collection Inventions, Paris, 2017, p.14. Dylan Trigg écrit encore p.15 : "l'horreur du corps signale la trahison d'une phénoménologie anthropocentrique et c'est exactement pour cette raison qu'elle signifie également son renouveau".


Anaëlle Bouloy

Jean-Michel Olivier

Jérémie Riquier

Emmanuel Castella

Pierre Marle

Nicolas Lamouroux

Spatio-temporal dynamics of habitat use by fish in a restored alluvial floodplain over two decades

Keywords: Habitat Complementarity, River restoration, Flow, Water temperature, Connectivity

River floodplain channels can serve as reproduction, nursery or refuge areas for fish. Although the complementary use of floodplain and main channels is known, few studies attempted to quantify this use and even fewer analysed its controlling factors. The objectives of this study are (1) to describe the spatio-temporal use of floodplain habitats and to identify their roles as complementary habitats for fish and (2) to analyse how abiotic variations and their modifications under restoration impact habitat use by fish. To meet these objectives, we analysed (Principal Components Analysis and Coinertia Analysis) multi-site data collected over 20 years in eight main channels and 23 floodplain channels of eight restored sectors of the French Rhône River. Results show that habitat use by fish is mainly related to spatial effects, with 37% of within-sector variance in taxonomic assemblages explained by the stations. As expected, rheophilic species were more abundant in lotic stations and limnophilic species in lentic ones. In addition, we identified an euryecious guild, grouping young of the year taxa (roach, gudgeon, chub, bleak) that used all types of habitats and particularly lentic floodplain channels with short life-span. Temporal effects (with ~10% of the variance explained by years) combine (1) the effect of restoration, that increased the diversity of fish assemblages across the floodplain, with stronger changes in floodplain channels whose connectivity regime was modified, (2) the effect of high flows on fish habitat use, that reinforces the nursery and refuge functions of floodplain channels. Our results demonstrate the importance of restoring the diversity of habitats and connectivity because floodplain habitats have complementary functions for fish. Furthermore, our results also suggest to account for temporal variations in order to better estimate the potential effects of restoration on river and their floodplains.

Introduction

A tenet of the patch dynamics concept [START_REF] Townsend | The patch dynamics concept of stream community ecology[END_REF] is the fundamental link between aquatic biodiversity and the spatio-temporal heterogeneity of the environment. This concept builds on major ecological theories and states that biodiversity increases with spatial heterogeneity and intermediate levels of temporal variability of the environment. River floodplains are suited for testing such relationships. In their aquatic components, they include the main river channel and a diversity of floodplain channels more or less connected to the former. These habitats and their connections are frequently modified by temporally variable water and sediment fluxes (Petts & Amoros, 1996).

In large river floodplains, aquatic habitat heterogeneity is known to favour fish diversity [START_REF] Amoros | Connectivity and biocomplexity in waterbodies of riverine floodplains: Connectivity and biocomplexity in riverine floodplains[END_REF][START_REF] Pander | Habitat diversity and connectivity govern the conservation value of restored aquatic floodplain habitats[END_REF][START_REF] Manfrin | The effect of lateral connectedness on the taxonomic and functional structure of fish communities in a lowland river floodplain[END_REF][START_REF] Stoffers | Freshwater fish biodiversity restoration in floodplain rivers requires connectivity and habitat heterogeneity at multiple spatial scales[END_REF]. Indeed, fish may use different habitat types during their life cycle [START_REF] Werner | Habitat requirements[END_REF][START_REF] Stoffels | Fragmentation of lateral connectivity and fish population dynamics in large rivers[END_REF], based on a trade-off between their habitat requirements (feeding, shelter and reproduction; [START_REF] Lévêque | L'habitat : Être au bon endroit au bon moment ?[END_REF][START_REF] King | Ontogenetic patterns of habitat use by fishes within the main channel of an Australian floodplain river[END_REF][START_REF] Brönmark | There and back again: Migration in freshwater fishes[END_REF] at different stages (larvae, juvenile and adult) and the accessibility of suitable habitats [START_REF] Plichard | Predictive models of fish microhabitat selection in multiple sites accounting for abundance overdispersion[END_REF][START_REF] Stoffels | Fragmentation of lateral connectivity and fish population dynamics in large rivers[END_REF]. According to [START_REF] Junk | The flood pulse concept in river-floodplain systems[END_REF], fish mainly use floodplain channels to accomplish their life cycle and use the main channels as migratory routes. But [START_REF] Galat | Conserving large-river fishes: Is the highway analogy an appropriate paradigm[END_REF] also demonstrated the importance of main channels in the life cycle of rheophilic species. For example, in the Danube River many larval rheophilic species use the banks as nursery areas [START_REF] Schiemer | Endangered fish species of the Danube river in Austria[END_REF][START_REF] Keckeis | Spatial and seasonal characteristics of O+ fish nursery habitats of nase, Chondrostoma nasus in the River Danube, Austria[END_REF]. Most studies on fish communities in riverine floodplains identified a spawning or nursery function in floodplain channels [START_REF] Copp | Ecology of fish spawning and nursery zones in the flood plain, using a new sampling approach[END_REF]. These functions depend on channel accessibility (via passive drift for some Youngs Of the Year (YOY) or active movement for all fish), characteristics of flood events and connectivity to the main channel [START_REF] Burgess | Importance of floodplain connectivity to fish populations in the Apalachicola River, Florida: floodplain connectivity[END_REF]. In floodplain channels the abundance of YOY is favoured by reduced hydraulic constraints that limit energy expenses [START_REF] Keckeis | Spatial and seasonal characteristics of O+ fish nursery habitats of nase, Chondrostoma nasus in the River Danube, Austria[END_REF][START_REF] Fustec | Fonctions et valeurs des zones humides[END_REF][START_REF] Silva | Identification of fish nursery areas in a free tributary of an impoundment region, upper Uruguay River, Brazil[END_REF] and an abundance of food (e.g. plankton) [START_REF] Fustec | Fonctions et valeurs des zones humides[END_REF][START_REF] Marle | Flow and plankton availability control young-of-the-year fish diet in two floodplain nurseries[END_REF]. Other studies reported a refuge function promoted by habitat diversity that attenuates the impact of disturbances like floods [START_REF] Townsend | The patch dynamics concept of stream community ecology[END_REF][START_REF] Townsend | Species traits in relation to a habitat templet for river systems[END_REF]. Indeed, during floods, organisms can access slow-flowing habitats in the floodplain [START_REF] Holcik | Influence of hydrological regime and water temperature on the activity and population density of fishes in the anabranches of the Danube. Prace Ust[END_REF][START_REF] Roux | Peuplements de Poissons[END_REF].

Human activities worldwide have affected the diversity and connectivity of habitats in most alluvial rivers [START_REF] Klingeman | Conceptualization for Long-Reach River Restoration[END_REF][START_REF] Nilsson | Fragmentation and Flow Regulation of the World's Large River Systems[END_REF][START_REF] Paillex | Testing predictions of changes in alien and native macroinvertebrate communities and their interaction after the restoration of a large river floodplain (French Rhône)[END_REF], reinforcing the need to better quantify the role of habitat complementarity for aquatic communities [START_REF] Stoffels | Fragmentation of lateral connectivity and fish population dynamics in large rivers[END_REF]. Historically, regulation for navigation, hydropower production, irrigation and/or flood protection often reduced flows [START_REF] Poff | Ecological responses to altered flow regimes: A literature review to inform the science and management of environmental flows: Review of altered flow regimes[END_REF][START_REF] Lehner | High-resolution mapping of the world's reservoirs and dams for sustainable river-flow management[END_REF]Lamouroux et al., 2015) and decreased the lateral and longitudinal connectivity [START_REF] Schiemer | Ecological status and problems of the Danube River and its fish fauna: A review[END_REF][START_REF] Tockner | Multiple stressors in coupled riverfloodplain ecosystems[END_REF]Lamouroux et al., 2015;[START_REF] Hein | Current status and restoration options for floodplains along the Danube River[END_REF][START_REF] Higgisson | Impacts of water resource development on hydrological connectivity of different floodplain habitats in a highly variable system[END_REF]. During the last decades, many river restoration programs were undertaken to improve the ecological conditions of degraded rivers (e.g. [START_REF] Statzner | Focusing environmental management budgets on non-linear system responses: Potential for significant improvements to freshwater ecosystems[END_REF][START_REF] Schiemer | Ecological status and problems of the Danube River and its fish fauna: A review[END_REF][START_REF] Palmer | Standards for ecologically successful river restoration: Ecological success in river restoration[END_REF][START_REF] Funk | Identification of conservation and restoration priority areas in the Danube River based on the multifunctionality of river-floodplain systems[END_REF][START_REF] Stoffers | 30 years of large river restoration: How long do restored floodplain channels remain suitable for targeted rheophilic fishes in the lower river Rhine?[END_REF]). Yet, the ecological effects of restoration remain rarely evaluated [START_REF] Palmer | Standards for ecologically successful river restoration: Ecological success in river restoration[END_REF][START_REF] Funk | Aquatic diversity in a former floodplain: Remediation in an urban context[END_REF][START_REF] Olden | Are large-scale flow experiments informing the science and management of freshwater ecosystems?[END_REF]Lamouroux et al., 2015) due to a lack of funding or sufficient and representative before-after monitoring [START_REF] Morandi | How is success or failure in river restoration projects evaluated? Feedback from French restoration projects[END_REF]. Long-term studies on the effects of floodplain restoration on fish communities are needed to better quantify the ecological benefits of habitat diversity improvements. However, such studies are expensive and remain uncommon (Lamouroux et al., 2015). Among exceptions, a 30 years-long study in the Rhine [START_REF] Stoffers | 30 years of large river restoration: How long do restored floodplain channels remain suitable for targeted rheophilic fishes in the lower river Rhine?[END_REF] highlighted the importance of the age of restored floodplain channels in their role as nurseries for rheophilic fish, with an optimum reached 13 to 14 years after restoration. Conversely, a 25 years-long study (1993 to 2018) in a tributary of the Colorado River [START_REF] Pennock | Failure to achieve recommended environmental flows coincides with declining fish populations: Long-term trends in regulated and unregulated rivers[END_REF] showed that both native and non-native fish declined in recent years despite flow management mimicking natural flows.

The Rhône river restoration programme that started in 1998 is a long-term and multi-site programme particularly suited for testing the ecological effects of floodplain restoration and identifying their key habitat drivers (Lamouroux et al., 2015). The French part of the Rhône River is highly regulated with 16 hydroelectric plants situated on artificial channels bypassing 162 km of the river, built between 1952 and1986 (Fig.1;[START_REF] Olivier | The Rhône River Basin[END_REF]. Bypassed sectors of the Rhône received a reduced minimum flow [1-20% of the unregulated mean flow before their restoration] during most of the year, but also large floods when the discharge capacity of the artificial channel is exceeded (Lamouroux et al., 2015;Fig. 1). Restoration operations that occurred between 2000 and 2014 increased minimum flows by a factor up to 10 (Table 1) and reach-averaged current velocities by a factor up to five [START_REF] Lamouroux | Testing predictions of changes in fish abundance and community structure after flow restoration in four reaches of a large river (French Rhône)[END_REF]. At the same time, about forty floodplain channels were restored, by dredging and/or increasing their connection to the main channels.

The scientific monitoring of the Rhône river restoration programme has involved data collection over more than 20 years, both before and after restoration, in eight restored river sectors, with an objective to develop and test quantitative predictions of the ecological effects of restoration. Syntheses available so far (Lamouroux et al., 2015) showed a significant increase after flow restoration of the proportion of fluvial specialist fish species, up to a factor of 2.4 in the main channels in some restored sectors [START_REF] Lamouroux | Testing predictions of changes in fish abundance and community structure after flow restoration in four reaches of a large river (French Rhône)[END_REF]. Studies on the Rhône restoration have not yet considered the combined influence of main and floodplain channels on fish assemblage dynamics. The purpose of the present study was to fill this gap.

Our objectives were (1) to describe the spatio-temporal habitat use by fish within the whole floodplain, (2) to identify the complementary roles of floodplain and main channels for groups of fish taxa with comparable habitat use (i.e., a posteriori guilds), (3) to analyse how annual, quantitative habitat variations (discharge, connection frequencies, water temperature) and restoration measures influenced fish habitat use over time. For this purpose, we used fish and environmental data (daily flows and water temperature) collected before and after restoration in eight sectors of the Rhône River over more than 20 years, including 31 sampling stations (eight main channels and 23 floodplain channels).

We expected (H1) higher spatial variations than temporal variations in fish assemblages, due to the wide range of lateral connectivity levels between stations at the sector scale [START_REF] Amoros | The Concept of Habitat Diversity Between and Within Ecosystems Applied to River Side-Arm Restoration[END_REF], (H2) marked changes in fish assemblages where restoration entailed abrupt changes in lateral connectivity (e.g. full channel reconnections), and (H3) a major influence of hydrological drivers on temporal changes because high waters modify the fish accessibility of floodplain channels [START_REF] Grift | Suitable habitats for 0-group fish in rehabilitated floodplains along the lower River Rhine[END_REF].

Material and Methods

Overall study design

Our study design (Fig. 2) included the definition of an a priori typology of stations, based on their connectivity with the main channel. Then, we performed a global within-sector principal component analysis (PCA) of the fish data to describe spatio-temporal variations in community structure within sectors. This analysis was used to test our hypotheses H1-H2. Finally, to test our hypothesis H3, we performed within-station co-inertia analyses (CoA), one for each a priori group of stations, focusing on the effects of environmental variables (flow and temperature) on annual fish variations.

Study sites and a priori typology

We considered eight sectors of the Rhône bypassed by artificial channels (Fig. 1, Table 1), corresponding to a total of 31 sampling stations: eight in the main channels and 23 in floodplain channels (up to six by sector). To facilitate graphical interpretations, we used an a priori typology of four groups of stations (two lotic and two lentic groups), based on their hydrological characteristics after restoration. For lotic stations, the first group corresponded to main channels (MC_Lot) and the second to floodplain channels permanently connected upstream and downstream to the main channel (FC_Lot); this second group also included floodplain channels connected downstream to the main channel and receiving small tributaries (Bièvre for CERI; Berre for MALA) or water diverted from the head race canal for PLAT (see Table 1 for station codes). Lentic stations were all floodplain channels, permanently connected downstream to the main channel and only temporarily connected upstream. The two groups of lentic stations were differentiated by the channel lifespan, i.e. the duration of the permanent aquatic stage, estimated by [START_REF] Riquier | Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics[END_REF] from observations of fine sediment accumulation rates. The first lentic group (FC_Lent_SL) consisted of floodplain channels with short estimated lifespan (15-30 years) where sedimentation processes were dominant and the rejuvenation capacity was low (i.e. scouring of fine deposits). The second (FC_Lent_LL) consisted of floodplain channels with longer lifespan (>30 years), due to higher shear stress during flood and lower backflow capacity. [START_REF] Riquier | Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics[END_REF] estimated these lifespans for 10 of the 13 lentic floodplain channels (those of sectors CE, BY, BC and PB in Table 1). We assigned the three remaining stations to the lentic groups based on our expertise and field observations. Lentic stations were often connected to groundwater (Table 1) and could have lower temperatures in summer than lotic stations.

Table 1: Sectors/stations considered, their codes, their sampling periods before and after restoration, and their a priori group of stations (after restoration). The Restoration field indicates stations whose connection with the main channel was changed by restoration. The a priori group names are based on the following rules: MC = Main Channel; FC = Floodplain Channel; Lent = Lentic; Lot = lotic; SL = Short Life span; LL = Long Life span. The upstream connection flows of lentic stations are also indicated (from [START_REF] Riquier | Hydromorphological conditions in eighteen restored floodplain channels of a large river: Linking patterns to processes[END_REF]; these connection flows are corresponding to discharge rate in the bypassed main channel, except for stations PONT, SAIN and BROT whose connections depend on the total Rhône discharge. The critical discharge (Qcrit, from Lamouroux et al. 2015), indicated for main channels, is a flow threshold that corresponds to the theoretical Shields critical flow rate for moving 20 mm gravel, using a dimensionless Shields criterion of 0.045 (Petit, 1994). The mean temperature (Tmean) during reproduction period (april-june) and growth period (july-august) are calculated from observed and modelled data between 2006 and 2016 in the BY and BC sectors. 1995-96 & 1998-99 [4]

A
2001-2019 [19] - - - Ciselande CISE FC_Lot [0] 2011 & 2013 [2] X X - - - Jaricot JARI FC_Lent_LL [0] 2011 & 2013 [2] X 1801 -c - Table ronde TABL FC_Lent_SL [0] 2011 & 2013 [2] X >3500 - - Péage-De-Roussillon Sector PR Main channel PR_M MC_Lot 2007-2013 [7] 2015-2019 [5] - - - Platière PLAT FC_Lot 2007-2013[7] 2014-2018 [5] - - - Noyer Nord NONO FC_Lot [0] 2007-2019 [12] X X - - - Noyer Sud NOSU FC_Lot [0] 2013-2019 [7] X X - - - Ilon ILON FC_Lent_SL 2007-08 & 2010-13 [6] 2014-2018 [5] 750 - - Sainte SAIN FC_Lent_SL [0] 2013-2015 [3] X 1700 - - Baix Sector LN Main channel LN_M MC_Lot 2010-2013 [4] 2014-2019 [6] - - - Montélimar Sector MO Main channel MO_M MC_Lot 2006-2013 [8] 2014-2019 [6] - - - Roussette ROUS FC_Lent_SL 2010-2011 [2] 2013 [1] 1000 -c - Donzère Sector DM Main channel DM_M MC_Lot 2008-11 & 2013 [5] 2014-2019 [6] - - - Malaubert MALA FC_Lot 2010-13 &2015-16 [6] 2017 [1] - - - a A priori

Fish sampling

Fish were sampled at each station on an annual basis, but with gaps and different durations among stations/sectors due to different restoration histories, as well as environmental, logistic and financial constraints (Table 1 andAppendix A). We considered fish samples taken from 1996 to 2019 between late August and mid-November (i.e. between late summer and autumn), when YOY are better identified (Table 1). Sampling effort was higher in the three sectors of the Upper-Rhône (upstream from Lyon, Fig. 1 (A)). The method used was point abundance sampling [START_REF] Nelva | Une nouvelle méthode d'étude des peuplements ichtyologiques dans les grands cours d'eau par échantillonnage ponctuel d'abondance[END_REF]. A fishing point corresponded to an electrode cast, representing a sampling area of about 7 m² [START_REF] Régis | A New Method for Evaluating the Efficiency of Electric Fishing[END_REF]. Points were distributed in the different microhabitats of the station considered (e.g., pools, runs, riffles, along the banks or midstream), in proportion to their availability. However, microhabitats deeper than 2 m were avoided because of the limits of electrofishing in these conditions. Electrofishing was mostly done from boat as detailed in [START_REF] Copp | Le rôle et le fonctionnement des milieux aquatiques du haut-Rhône français comme sites de reproduction et de nurserie pour les poissons du fleuve[END_REF] and [START_REF] Persat | Electric fishing and point abundance sampling for the ichthyology of large rivers[END_REF], or by wading in shallower areas using an EFKO FEG 5000 generator delivering a continuous current. The fishing effort (number of fishing points) was relatively constant over years (generally about 25 points in floodplain channels and 100-200 points in main channels). All fish individuals were identified (in the field or at the laboratory for complex species like bream and silver bream), measured and released.

We built a table of abundance of specific size classes, by station × year. Size limits for YOY (noted e.g. "BaBu1" for species code "BaBu"; see Table 2 for species codes) were set for each station × year combination from visual appreciation of size class histograms. Other fish (not identified as YOY) were classified with similar fixed size limits for all species (e.g. BaBu2: < 12 cm, BaBu3: 12-18 cm, BaBu4: >18 cm), because size can be a strong determinant of habitat use [START_REF] Plichard | Predictive models of fish microhabitat selection in multiple sites accounting for abundance overdispersion[END_REF]. The abundance table contained a total of 367 station × year combinations, and 82 specific size-classes of 37 species. Abundance data were transformed to "log-densities": log(1 + abundance per 100 m²) for approaching normal distributions, accounting for variable sampling efforts and reducing the influence of aggregative behaviour, especially observed for YOY.

Environmental data (flow and temperature)

Environmental variables were described for post-restoration years only and pre-restoration dates were not included, to avoid confounding annual environmental effects and those of restoration. Flow variables were derived from daily discharge records at eight gauging stations located in the main channels of each sector (Fig. 1A). We also used daily flows at three gauging stations in the "total Rhône" (downstream of the junction between the tail race and the bypassed channel, see Fig. 1B) for estimating the connection frequency of stations connected to this part of the river (BROT, PONT and SAIN, Table 1). For each station × year, we described mean flows (Qmean) and high flows (the 90% high flow percentile: Q90, and the duration exceeding the critical flow threshold moving fine gravel: Dcrit) in the relevant main channel, and connection durations (Dconn) of floodplain channels at three periods of importance for fish dynamics (see Table 3 for variable definitions). These three periods were reproduction (April-June), growth (July-August) and pre-sampling (the month preceding sampling; [START_REF] Daufresne | Long-term changes within the invertebrate and fish communities of the Upper Rhône River: Effects of climatic factors: Climate change and freshwater communities[END_REF]. These fixed period definitions did not account for complex variations in life cycle dynamics between species and years, but we considered them suitable for a community-wide analysis.

Table 3: Definitions of the four flow variables and three water temperature variables used. The three periods used to calculate these variables (from [START_REF] Daufresne | Long-term changes within the invertebrate and fish communities of the Upper Rhône River: Effects of climatic factors: Climate change and freshwater communities[END_REF] Water temperature variables for post-restoration years were derived from [START_REF] Marle | Thermal regime, together with lateral connectivity, control aquatic invertebrate composition in river floodplains[END_REF], for the BY and BC sectors only. These authors used hourly temperature records at main and floodplain channels stations between 2006 and 2016 and modelled missing values (~31% of data) with random forest algorithms (R package missForest; Stekhoven & Buehlmann, 2012). At each station × year, we calculated mean temperature (Tmean) and temperature extremes (T10 and T90 quantiles) for the three periods used for discharge ( Table 3). The mean temperature (Tmean) during reproduction and growth periods are given in Table 1 to assess variations of temperature conditions among stations.

Spatio-temporal use of a priori groups of stations and effect of restoration (within-sector PCA)

We first performed a within-sector PCA of the fish table including all eight sectors in a single analysis [START_REF] Dolédec | Rythmes saisonniers et composantes stationnelles en milieu aquatique II-Prise en compte et élimination d'effets dans un tableau faunistique[END_REF]; R package ade4; [START_REF] Chessel | The ade4 Package -I: One-Table Methods[END_REF][START_REF] Core | R: A language and environment for statistical computing[END_REF]. We chose a withinsector PCA to remove average differences in densities between sectors, which can be due to regional difference and the general organization of fish communities along longitudinal gradients [START_REF] Huet | Profiles and Biology of Western European Streams as Related to Fish Management[END_REF]. Therefore, the analysis focused primarily on the spatio-temporal variations in community structure within sectors. We also calculated the part of variance of the within-sector community variation explained by space (stations) and time (years).

On the factorial map of the within-sector PCA, we identified stations according to the four a priori groups presented above, in order to assess spatial differences in community structure. Based on the results of the within-sector PCA, we created a posteriori guilds (groups of specific size-classes) with comparable habitat use, in order to simplify the interpretation. For this purpose, we used a hierarchical clustering analysis [START_REF] Müllner | fastcluster: Fast Hierarchical, Agglomerative Clustering Routines for R and Python[END_REF] with the Ward method [START_REF] Murtagh | Ward's Hierarchical Agglomerative Clustering Method: Which Algorithms Implement Ward's Criterion?[END_REF], based on the Euclidean distances between the scores of the taxa along the within-sector PCA axes.

In order to assess the effects of restoration on fish community composition, despite the limited number of pre-restoration samples, we compared the fish compositions on the within-sector PCA factorial maps before and after restoration. We particularly focused on floodplain channels that underwent changes in connectivity after restoration and for which pre-restoration data were available (Table 1). No statistical test was made to analyse these changes, as most floodplain channels were sampled only once before restoration. Indeed, observed changes may be due to restoration, but also to particular conditions during the pre-restoration year.

Inter-annual variations in fish habitat use after restoration and influence of flow and temperature (within-station coinertia analyses)

We analysed the influence of flow and temperature variables on fish density variations, for each of the four a priori groups of stations, with dedicated within-station coinertia analyses (CoA; [START_REF] Dolédec | Co-inertia analysis: An alternative method for studying speciesenvironment relationships[END_REF]. Although this choice generates several multivariate analyses, we preferred CoA over other methods, such as mixed-effects regressions, due to the fact that our analyses involved a fairly high number of environmental variables compared to the number of statistical individuals (station x years). Regressions have low statistical power and are difficult to interpret in such conditions. Conversely, CoA calculates pairs of multivariate environmental and fish axes that are the most covariant. Therefore, CoA results express a compromise between the fish variance, the environmental variance, and the correlation between them. CoA is adapted to our situation with a high number of explanatory variables and enables multivariate interpretations [START_REF] Dray | Co-inertia analysis and the linking of ecological data tables[END_REF]. Using within-station CoA enables to remove average differences between stations, and thus to focus on temporal changes within all stations of the group considered.

To simplify the interpretation of CoAs, we performed the analyses on fish log-densities within a posteriori guilds (sum of log-densities of individual life stages). For each CoA, flow variables that were not relevant for the station type were not involved: in detail, Dconn was not considered for lotic stations and Dcrit for lentic ones. Temperature variables were available in a sufficient number of stations for FC_Lent_LL stations only and were not involved in the analyses of other station types. This implied that the CoA for FC_Lent_LL was performed only on data between 2006 and 2016, and only on the FC_Lent_LL stations of the BY and BC sectors (period and sector with available temperature). We tested the significance of each CoA with a Monte-Carlo test on the sum of eigenvalues, with 10 000 iterations (RV.rtest function in the ade4 R package; [START_REF] Chessel | The ade4 Package -I: One-Table Methods[END_REF].

Results

Spatio-temporal use of a priori groups of stations and effect of restoration

The sector effect explained 15% of the overall spatio-temporal variation in the abundance of fish taxa. The remaining variation was partly accounted for by differences between stations (37%) and between years (10%).

The cluster analysis of taxa scores along the within-sector PCA axes (Fig. 3, with results of the hierarchical clustering analysis in Appendix B) identified a posteriori guilds that we interpreted as rheophilic (three guilds Rheo_3T, Rheo_16T, and Rheo_4T; with the last two or three digits of each acronym indicating the number of taxa included), limnophilic (two guilds Limno_9T and Limno_4T), euryecious (a single guild Eury_4T), and a last guild grouping the remaining taxa (Other) that contributed little in the analysis. This last guild (Other) includes 42 taxa that did not form an obvious functional group and were grouped because they had low abundance in the samples. We named guilds based on the flow characteristics of the stations where they occur, as revealed by the juxtaposition of Figures 3 and4.

The three rheophilic guilds were associated with lotic stations (MC_Lot and FC_Lot; Fig. 4). However, taxa of the Rheo_3T guild were more abundant in the MC_Lot stations of the Upper Rhône (BC, BY and CE sectors; Figures 3 and4, Appendix C). Taxa of the Rheo_16T guild had comparable abundance between most lotic stations. Finally, the Rheo_4T guild was particularly abundant in the MC_Lot of CE and LN sectors, and was also present in significant numbers in two FC_Lent_LL stations (FOUR and MALO stations, see Appendix C).

Taxa of the two limnophilic guilds preferentially used FC_Lent_SL stations (Fig. 4). Limnophilic guilds were also abundant in the MC_Lot station of the PR sector (Fig. 3 and Fig. 4). They used FC_Lent_LL stations to a lesser extent, in particular MOIR and BROT stations (Fig. 3 and Fig. 4; Appendix C). The difference between the two guilds of limnophilic taxa was mainly related to differences in taxon density, with amur bitterling and stone moroko (Limno_4T guild) having larger densities than the taxa of the Limno_9T guild (see Appendix C).

Finally, taxa of the euryecious guild were abundant in three of the four habitat types (MC_Lot, FC_Lot and FC_Lent_SL; Fig. 3 and4). Taxa of this guild were YOY (chub, bleak, gudgeon, and roach); the other size classes of these species were members of the rheophilic guilds (Fig. 3).

Fig. 3.

Scores of taxa on the centred within-sector PCA on fish log-densities (axes 1 and 2). A cluster analysis grouped taxa into seven guilds. Taxa labels are not indicated for the "Other" guild (except sticklebacks, GaG), because they contribute little to the fish structure and would complicate the reading. See Table 2 for taxa codes. 1 for stations and sector code.

Floodplain channels whose connection regime changed after restoration (Table 1) showed modifications in the structure of their fish community. Stations that became lotic following upstream and/or downstream reconnection (MATH, ENIL and VACH; Fig. 5A) were rapidly used by rheophilic taxa (Fig. 3). Stations that were reconnected downstream changed in two ways. Stations PONT and MOLO (Fig. 5A) were rapidly used by limnophilic and euryecious taxa. Station MALO (Fig. 5A) remained weakly favourable to fish. The effects of restoration were not obvious in most of the other stations that were only dredged, with no surface reconnection. In particular, FC_Lent_LL stations such as MOIR, LUIS and GRAN, had a low density and diversity of fish both before and after restoration (Fig. 3). Concerning the effects of restoration over time, we did not observe any obvious trend in post-restoration data (Fig. 5).

When considering sectors with more than three restored channels with pre-and post-restoration data (BC and BY), the diversity of fish assemblage in each station x date clearly increased in the BC sector (larger ellipses after restoration on Fig. 5B), but not in BY (Fig. 5B). 1 for sector and station codes. The year in brackets corresponds to the restoration year. B) At the sector scale with the Belley sector (BY: in which four stations have been restored and have before and after data, one of which has changed its connection regime see Fig. 6A) and Br´egnier-Cordon sector (BC: in which six stations have been restored and have before and after data, four of which have changed their connection regime, see Fig. 6B). The ellipses show the 67 % normalized distribution of scores, before and after restoration.

Inter-annual variations in fish habitat use after restoration and the influence of flow and temperature

The CoA analyses carried out for each a priori group of stations indicated which environmental variables were covariant with annual variations in guild densities (Fig. 6). The associated significance were P = 0.002 for FC_Lent_LL, P = 0.055 for MC_Lot and P = 0.09 for FC_Lot. The CoA for FC_Lent_SL, that involved few station x dates, was not significant (P = 0.57). The effects of flow variables are summarized in Table 4. High flows during the reproduction period (April-June) covaried positively with the log-densities of Eury_4T guild observed later in lentic stations (FC_Lent_SL and FC_Lent_LL) and with the log-densities of Rheo_3T and Rheo_16T guilds in lotic stations (MC_Lot and/or FC_Lot). High flows during the growing period (July-August) covaried negatively with the log-density of Rheo_3T guild in MC_Lot, but positively in FC_Lot. Furthermore, Eury_4T log-densities covaried negatively with long duration of upstream connection (Dconn) in FC_Lent_SL. Finally, during the sampling period, the log densities of guilds covaried negatively with high flows in MC_Lot for 3 out of 6 guilds, and positively in the floodplain channels (Table 4). The log-density of Limno_9T guild covaried negatively with high flows in FC_Lent_SL whatever the period considered.

The effects of temperature variables, tested for FC_Lent_LL stations only, were secondary compared to the effects of flow. The CoA indicated that the Rheo_16T guild covaried positively with high temperatures during the sampling period, contrarily to the Rheo_4T and Eury_4T guilds (Fig. 6).

Fig. 6. Results of the four CoA analyses on the six a posteriori guilds of fish defined above and environmental (flow and temperature) datasets. Left panels show the environmental variable scores on axes 1 and 2; right panels show the posteriori guilds scores on axes 1 and 2. The text illustrates the interpretation of environmental axes. See Table 3 and Fig. 3 for variables codes and a posteriori guilds.

For reasons of readability, environmental and fauna variables with a score between -0.3 and 0.3 were removed from the graphs.

Table 4: Summary of the main results of this study. (1) The composition of the six a posteriori guilds defined by the hierarchical clustering analysis on the within-sector PCA. ( 2) The a priori groups of stations used preferentially by the a posteriori guilds.

(3) The effects of high flows during the three selected periods on a priori group of stations used by the a posteriori guilds thanks to the four withinstation co-inertia analyses.  : positive covariance and  : negative covariance between density of taxa and high flow.

Within-sector PCA results (Spatial distribution of a posteriori guilds among a priori groups)

CoA Results (Temporal change in a priori group use with high flows)

A posteriori Guilds

Taxa (hierarchical clustering)

A priori groups used preferentially Reproduction period (_R)

Growth period (_G) Sampling period (_S) Eury_4T AlA1 GoG1 SqC1 RuR1 MC_Lot; FC_Lot; FC_Lent_SL  FC_Lent_SL  FC_Lent_LL  FC_Lot FC_Lent_SL (Dconn)  FC_Lent_SL  FC_Lent_LL  FC_Lot MC_Lot Limno_9T ScE1 ScE2 TiT1 TiT2 AmM2 LeG1 LeG2 AbB1 BlB1 FC_Lent_SL FC_Lent_SL  FC_Lent_LL FC_Lent_SL FC_Lent_SL  FC_Lent_LL Limno_4T PsP1 PsP2 RhS1 RhS2 FC_Lot_SL FC_Lent_SL  FC_Lent_LL FC_Lent_SL  FC_Lent_LL Rheo_16T AlA2 AlA3 BaBu2 BaBu3 BaB4 BlB2 SqC3 SqC4 RuR2 RuR3 GoG3 ChN1 AlB1 AlB2 LeL1 LeL2 MC_Lot; FC_Lot  FC_Lot (except for Dcrit)  FC_Lent_LL  FC_Lot MC_Lot FC_Lot  FC_Lent_LL Rheo_3T BaBu1 GoG2 SqC2 MC_Lot; FC_Lot  MC_Lot  FC_Lot  MC_Lot  FC_Lot (except for Dcrit)  MC_Lot Rheo_4T BaBa1 BaBa2 PhP1 PhP2 MC_Lot; FC_Lot; FC_Lent_LL  FC_Lent_LL  MC_Lot  MC_Lot  FC_Lent_LL

Discussion

Habitat complementarity for fish in river floodplain

The spatio-temporal analysis of fish communities essentially reflected spatial effects and indicated a strong influence of habitat types, based upon their hydraulic connection within the floodplain, on observed fish community structure. As expected, rheophilic species were more abundant in lotic stations and limnophilic species in lentic ones. This confirms, with numerous stations and long-term data, the general distribution patterns of floodplain fish communities observed in alluvial rivers around the word [START_REF] Tales | Les peuplements de poissons de l'année de quelques types d'annexes fluviales dans la plaine de la Bassée (Seine)[END_REF][START_REF] Galat | Conserving large-river fishes: Is the highway analogy an appropriate paradigm[END_REF]. In addition, we identified an euryecious guild, grouping several YOY taxa (roach, gudgeon, chub, bleak), that used all types of floodplain habitats and particularly floodplain channels with short life duration, even if the corresponding adult stages mostly used lotic habitats. This pattern suggests a nursery function of floodplain channels, confirming previous observations [START_REF] Grift | Suitable habitats for 0-group fish in rehabilitated floodplains along the lower River Rhine[END_REF][START_REF] Humphries | Creating a disturbance: Manipulating slackwaters in a lowland river[END_REF][START_REF] Bolland | The Importance of Variable Lateral Connectivity Between Artificial Floodplain Waterbodies and River Channels[END_REF].

Our results also indicated that habitat use varied in time as a function of flow. Indeed, covariance between the annual variations of fish after restoration and discharge variables suggested that high flows were major drivers of fish habitat use, with effects depending on the period of high flow occurrence and on the different habitat requirement of fish taxa.

A functional complementarity between floodplain habitats

The spatio-temporal analysis and our focus on inter-annual variations suggested three main functions of floodplains, each differently influenced by flow variations.

The "nursery" function is the main function revealed by our results and was confirmed by elements of the inter-annual analysis, which indicated that high flows during the pre-sampling period increase the use of lentic habitats by YOY of chub, bleak, gudgeon and roach. High flows can facilitate a passive drift of early developmental stages (larvae) present in the main channel towards floodplain habitats [START_REF] Lechner | Hydraulic forces impact larval fish drift in the free flowing section of a large European river: hydraulic forces impact larval fish drift[END_REF]) because of their poor swimming ability [START_REF] Reichard | Spatial distribution of drifting cyprinid fishes in a shallow lowland river[END_REF]. The nursery function was mainly associated with lentic stations where a high sedimentation rate shortened the persistence of aquatic habitats. The other lentic stations of longer duration such as LUIS, FOUR or BEAR had a very limited nursery function, and more generally a low density and diversity of limnophilic species. Several hypotheses can be put forward to explain this functional difference between the two types of lentic habitats. First, water temperature in short-lived floodplain channels such as MOLO and PONT (Table 1) was higher during the juvenile growth period (July-August) than in long-lived floodplain channels, the latter probably receiving a higher groundwater inflow. Higher temperature often has a positive impact on food production that imply a better growth of juveniles [START_REF] Cowx | Potential impact of groundwater augmentation of river flows on fisheries: A case study from the River Ouse, Yorkshire, UK: IMPACT of GROUNDWATER augmentation on fisheries[END_REF][START_REF] Bruslé | Biologie des poissons d'eau douce européens (2e éd[END_REF]. Secondly, in long-lived lentic stations short but intense floods generate high shear stress that can limit sedimentation rates [START_REF] Riquier | Hydromorphological conditions in eighteen restored floodplain channels of a large river: Linking patterns to processes[END_REF][START_REF] Riquier | Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics[END_REF]. This may act as hydraulic disturbances for YOY fish, macroinvertebrates and macrophytes [START_REF] Padial | The role of an extreme flood disturbance on macrophyte assemblages in a Neotropical floodplain[END_REF]. In particular, macrophytes can provide egg-laying substrate, shelter and feeding areas for fish [START_REF] Hamilton | Zooplankton abundance and evidence for its reduction by macrophyte mats in two Orinoco floodplain lakes[END_REF][START_REF] Delariva | Ichthyofauna associated to aquatic macrophytes in the Upper Paraná River floodplain[END_REF][START_REF] Casatti | Aquatic macrophytes as feeding site for small fishes in the Rosana Reservoir, Paranapanema River, Southeastern Brazil[END_REF]. This is consistent with observations of [START_REF] Marle | The interplay of flow processes shapes aquatic invertebrate successions in floodplain channels-A modelling applied to restoration scenarios[END_REF] who reported high abundance of Elodea nuttallii (H. St. John, 1920) and Ceratophyllum demersum (Linnaeus, 1753) in MOLO station, a short-lived channel associated with shallow depths and silty substrate. Consistently, despite their weak nursery role, the spatio-temporal analysis indicated that long-lived floodplain channels could be used by species living in cooler waters (e.g. minnow, stickleback and stone loach, [START_REF] Huet | Profiles and Biology of Western European Streams as Related to Fish Management[END_REF]. This is particularly the case at the MALO station (in the CE sector).

An "effective reproduction" function was suggested by the positive influence of high flows during the reproduction period on the recruitment of the euryecious guild in lentic habitats and the rheophilic guilds (Rheo_3T and Rheo_16T) in lotic habitats. It is likely that YOY of the rheophilic guilds originate from spawning in lotic environments, particularly because barbel, nase and spirlin breed in shallow water with high current velocity and coarse substrate (gravel and pebble) [START_REF] Keith | Atlas des poissons d'eau douce de France[END_REF].

Concerning YOY of the euryecious guild, their reproduction could have taken place either directly in lentic environments, or in lotic environments from which they subsequently drifted [START_REF] Lechner | Hydraulic forces impact larval fish drift in the free flowing section of a large European river: hydraulic forces impact larval fish drift[END_REF] towards their growth zones; the latter hypothesis is particular likely for chub, which requires gravel substrate for spawning [START_REF] Keith | Atlas des poissons d'eau douce de France[END_REF]. A study by [START_REF] Bounket | Spawning areas and migration patterns in the early life history of Squalius cephalus (Linnaeus, 1758): Use of otolith microchemistry for conservation and sustainable management[END_REF] on chub in the Rhône River showed that 90% of the YOY sampled in a lotic floodplain channel (MALA station in the DM sector) originated from the floodplain channels themselves and that only 6.5% came from the main channel (3.2% of undetermined origin). Conversely, according to our results, high flows during reproduction appear to reduce the recruitment of limnophilic species, especially in short-lived lentic channels. These results must be further investigated because high flows can also be favourable for the reproduction of some limnophilic and phytophylic species such pike by allowing access to spawning areas [START_REF] Keith | Atlas des poissons d'eau douce de France[END_REF]. This differential effect of flows on fish reproduction was described in previous research [START_REF] Cattanéo | Does hydrology constrain the structure of fish assemblages in French streams? Local scale analysis[END_REF][START_REF] Scharbert | Relationships of hydrology and life-history strategies on the spatio-temporal habitat utilisation of fish in European temperate river floodplains[END_REF]. For example, a two-year study in the Volga River floodplain [START_REF] Górski | Fish spawning in a large temperate floodplain: The role of flooding and temperature: Spawning of fish in relation to flood pulse and temperature (Volga)[END_REF] revealed a synchrony between the spawning of rheophilic fish and flood events that was not observed for limnophilic species.

A "flow refuge" function was suggested by the influence of high flows during the growth period on rheophilic species (Rheo_3T), probably moving from fast-flowing main channels (MC_Lot) to lotic floodplain channels (FC_Lot). This refuge function of the floodplain channels was observed in other shorter-term studies with analyses generally based on a single year [START_REF] Schwartz | Fish use of stage-specific fluvial habitats as refuge patches during a flood in a low-gradient Illinois stream[END_REF][START_REF] Bolland | The Importance of Variable Lateral Connectivity Between Artificial Floodplain Waterbodies and River Channels[END_REF]. In addition, high flows preceding sampling reduced the abundance of three guilds (Eury_4T, Rheo_16T and Rheo_3T) in the main channels and increased the abundance in lentic floodplain channels (for Eury_4T, Rheo_16T, Rho_4T), suggesting an escape from fast currents. It should be noted that high flows can also induce movements to the bottom substrate (demonstrated for rainbow trout by [START_REF] Pert | Habitat Use by Adult Rainbow Trout under Moderate Artificial Fluctuations in Flow[END_REF] that were not detectable given our point sampling method.

How did restoration favour new habitats, nursery and refuge functions?

In the spatio-temporal analysis, trajectories of stations with pre-restoration data available suggested that the main effects of restoration concerned channels becoming lotic and a limited number of channels becoming short-lived. Restored lotic floodplain channels offered new habitats colonized by rheophilic species, in addition to their role as refuge for these species (see above). In restored shortlived floodplain channels, the increase of limnophilic and euryecious taxa suggested a positive effect of restoration that created habitats for limnophilic taxa and improved the nursery function for euryecious taxa. The weaker changes observed in long-lived floodplain channels were consistent with their weak nursery role, and probably their lower temperature during the growth period. It should be noted that the restoration targeted such increased groundwater inflows in LUIS, FOUR and BEAR stations. However, the low levels of dissolved oxygen in groundwater can limit zooplankton production and therefore impact fish foraging and thus survival [START_REF] Marle | Flow and plankton availability control young-of-the-year fish diet in two floodplain nurseries[END_REF]. Concerning the long-term effect of restoration, the absence of trend in fish response after restoration suggests that the temporal variations were mainly due to annual environmental variations.

Overall, restoration increased the diversity of species using floodplain habitats. At Brégnier-Cordon, where four floodplain channels had their connections modified, restoration clearly increased the spatio-temporal diversity of fish assemblages across the floodplain. Such a floodplain-level response was not observed at Belley, where only two channels had their connections restored. It is also possible that the environmental configurations of the sectors (e.g. habitat heterogeneity and connectivity of channels) influenced the success of the restoration. Among restoration measures, the restoration of short-lived floodplain channels enabled them to become habitats of high fish diversity and to play a role in the growth of YOY rheophilic species. These channels became priority habitats for limnophilic species.

Limits of our interpretation

A full interpretation of the observed temporal variability remains difficult due to the combined influence on fish communities of multiple abiotic and biotic processes [START_REF] Cauvy-Fraunié | Interpretation of interannual variability in long-term aquatic ecological surveys[END_REF]. In particular, we mostly related the temporal effect to high flows, in accordance with other studies [START_REF] Bain | Streamflow Regulation and Fish Community Structure[END_REF][START_REF] Poff | Functional Organization of Stream Fish Assemblages in Relation to Hydrological Variability[END_REF][START_REF] Taylor | Meta-analyses of the effects of river flow on fish movement and activity[END_REF]. However, many other biotic and abiotic variables, not considered here, can impact fish communities. These variables include predation, competition for resources, pollutants, oxygen concentration, nutrients, substrate (considered indirectly in our habitat typology; [START_REF] Riquier | Hydromorphological conditions in eighteen restored floodplain channels of a large river: Linking patterns to processes[END_REF][START_REF] Riquier | Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics[END_REF] and light [START_REF] Bruslé | Biologie des poissons d'eau douce européens (2e éd[END_REF]. Finally, as the data were collected over more than 20 years (with only one sampling per year), variability due to sampling efficiency and timing was difficult to avoid [START_REF] Trenkel | Different surveys provide similar pictures of trends in a marine fish community but not of individual fish populations[END_REF].

Another important limitation is the insufficient statistical power of the coinertia analysis of short-lived lentic habitats, which is probably the reason for the lack of significance of this particular analysis.

Although the interpretations of this analysis are consistent with our initial hypotheses as well as with the literature, they should be taken with caution. Another important limit concerns the interpretation of the influence of high flows on reproduction success. We defined a fixed reproduction period for all fish species (April -June) in order to perform a general analysis of the fish communities [START_REF] Daufresne | Long-term changes within the invertebrate and fish communities of the Upper Rhône River: Effects of climatic factors: Climate change and freshwater communities[END_REF]. However, this period does not consider the complexity of each specific life history. The reproduction of early spawners (e.g. pike, nase, dace, roach; [START_REF] Ovidio | Movement patterns and spawning activity of individual nase Chondrostoma nasus (L.) in flow-regulated and weir-fragmented rivers[END_REF] and that of species that reproduce later (e.g. bleak, tench, rudd; [START_REF] Tissot | Synthèse des tolérances thermiques des principales espèces de poissons des rivières et fleuves de plaine de l'ouest européen[END_REF] are not influenced by the same flow rates. In addition, due to the limited temperature data, we were unable to look at the interaction between temperature and flow rates, the combination of which influences reproductive mechanisms [START_REF] Rolls | Fish recruitment in rivers with modified discharge depends on the interacting effects of flow and thermal regimes[END_REF].

Lessons for efficient restoration measures

Our results demonstrated the importance of restoring habitat diversity and connectivity in riverine floodplains because habitats may have complementary functions for fish [START_REF] Pander | Habitat diversity and connectivity govern the conservation value of restored aquatic floodplain habitats[END_REF]. This complementarity is often discussed in the literature [START_REF] Lévêque | L'habitat : Être au bon endroit au bon moment ?[END_REF][START_REF] Werner | Habitat requirements[END_REF][START_REF] Schwartz | Fish use of stage-specific fluvial habitats as refuge patches during a flood in a low-gradient Illinois stream[END_REF], but has rarely been demonstrated on long-term and multi-site data. Therefore, our conclusions can potentially be transposed to other large alluvial rivers in the temperate zone (see also [START_REF] Ramler | Effects of large-river restoration measures on ecological fish guilds and focal species of conservation in a large European river (Danube, Austria)[END_REF][START_REF] Manfrin | The effect of lateral connectedness on the taxonomic and functional structure of fish communities in a lowland river floodplain[END_REF][START_REF] Stoffers | 30 years of large river restoration: How long do restored floodplain channels remain suitable for targeted rheophilic fishes in the lower river Rhine?[END_REF].

Results highlighted the importance of short-lived floodplain channels, which have various functional roles for fish (i.e. nursery and refuge) and are also preferred habitats for limnophilic species. These floodplain channels were often completely disconnected and inaccessible for fish before restoration.

They were reconnected at their downstream end to a lotic habitat and share a common trend of rapid fine sediment infilling after restoration. For the same reason, however, these habitats are not selfsustainable and will likely disappear in less than 30 years [START_REF] Riquier | Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics[END_REF], with a progressive decrease in their functional roles. This means that the restoration actions carried out in this type of channels might have to be repeated, when the river is no longer able to generate this type of habitat by itself.

We also showed that the presence of lotic floodplain channels permanently connected to the main channel was important, especially for rheophilic species that can use them as refuge areas. Before restoration, these were either completely disconnected from the main channel, or connected downstream. After restoration, most of these floodplain channels are currently shown to be selfsustainable and to preserve a gravel substrate under the prevailing conditions [START_REF] Riquier | Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics[END_REF].

Finally, we showed that long-lived floodplain channels with higher shear stress during high flows and lower temperature during the growth period are not suitable habitats for YOY and their often oligotrophic nature gives them limited trophic conditions for adults. However, we recommend maintaining some of these channels that seem to be used by a limited number of cold water fish species (i.e. minnow and stone loach). Indeed, they may be used by specific macroinvertebrate assemblages [START_REF] Brunke | Patchiness of River-Groundwater Interactions within Two Floodplain Landscapes and Diversity of Aquatic Invertebrate Communities[END_REF] and can be increasingly important in the context of global warming.

Perspectives

Our study indicates complementary functions of the main and floodplain channels. These functions are influenced by high flows and were improved by restoration in the case of the Rhône River. Further studies could better account for other variables in addition to flows and temperature, such as the magnitude of groundwater inflows, the density and diversity of food resources (i.e. macroinvertebrates), and/or the availability of spawning areas (i.e. combinations of substrate, vegetation and accessibility characteristics). Furthermore, the complementarity of floodplain habitats could be better understood by focusing on population dynamics of selected species, based on a detailed analysis of spatio-temporal variations in size class distributions. This study may contribute to the selection of species for such more detailed analyses of the complementarity between habitats in the floodplain. In particular, it would be important to focus on abundant species that clearly use different habitats, such as bleak. Other candidates are species with periodic reproduction strategy, (e.g. chub, roach, barbel and nase; [START_REF] Blanck | Relationships between life-history strategies of European freshwater fish species and their habitat preferences[END_REF] that synchronise their spawning with optimal environmental conditions [START_REF] Winemiller | Patterns of Life-History Diversification in North American Fishes: Implications for Population Regulation[END_REF].

This study was funded by the Agence de l'Eau Rhône-Méditerranée-Corse, the Compagnie Nationale du Rhône, the Région Provence-Alpes-Côte d'Azur, Electricité de France and the Syndicat du Haut-Rhône.

Fig. 1 .

 1 Fig. 1. (A) Map of the Rhône River showing the eight sectors considered in this study. In [] are the code for each sector and in () the year in which restoration occurred. (B) Example of a Rhône sector (CE in Table 1) bypassed by an artificial channel (on the left) for hydropower production © IGN BD Ortho 2013; Lamouroux et al., 2015. (C) Discharge in the bypassed main channel and in the total Rhône for a given year. Bypassed discharge is reduced to a minimum flow except during flood

Fig. 2 .

 2 Fig. 2. Conceptual diagram of the study design. Presentation of data, methods and results and their link with our three hypotheses (H1 = Higher spatial than temporal variations in fish assemblages; H2 = Marked changes in fish assemblages where restoration entailed abrupt changes in lateral connectivity; H3 = Major influence of hydrological drivers on temporal changes (Q: discharge, T: temperature). (FC_Lot in orange, FC_Lent_LL in dark blue and FC_Lent_SL in turquoise); see Section 2.2 for station type definitions

  group of stations: MC_Lot: Main channel; FC_Lot: Lotic floodplain channel; FC_Lent_LL: Lentic and long-lived floodplain channel; FC_Lent_SL: Lentic and Short-lived floodplain channel b Restoration type: Up: upstream reconnection; Down: downstream reconnection c stations where restoration increased the connection to groundwater

Fig. 4 .

 4 Fig. 4. Scores of stations × years on the centred within-sector PCA on annual log-densities of the 82 taxa sampled in eight sectors. Polygons group scores by station, and their colours indicate their belonging to a priori groups of stations. SeeTable 1 for stations and sector code.

Fig. 5 .

 5 Fig. 5. Scores of stations × years on the centred within-sector PCA, as in Fig. 4. A) At the station scale: detail of the temporal trajectory for the six stations whose connection regime changed after restoration. Labels indicate sampling years, pre-restoration years are bolded. See Table1for sector and station codes. The year in brackets corresponds to the restoration year. B) At the sector scale with the Belley sector (BY: in which four stations have been restored and have before and after data, one of which has changed its connection regime see Fig.6A) and Br´egnier-Cordon sector (BC: in which six stations have been restored and have before and after data, four of which have changed their connection regime, see Fig.6B). The ellipses show the 67 % normalized distribution of scores, before and after restoration.

Table 2 :

 2 The

	Mean density (fish/100m²)

37 fish species sampled. The species code is based on the Latin name and is accompanied by size classes which are present in the sample (1 = YOY; 2 = fish <12 cm; 3 = 12 cm> fish <18 cm and 4 = fish > 18 cm; -= no size class). The table indicates species average post-restoration densities in the four a priori group of stations (see Table

1

for codes). Species are ranked by decreasing density

Acknowledgments

We thank all the people involved in the RhônEco programme, coordinated by ZABR (Zone Atelier du Bassin du Rhône, LTSER France) in the framework of the Observatoire-Hommes-Milieux (OHM Vallée du Rhône) and the graduate school EUR H2O'Lyon (ANR-17-EURE-0018). In particular, we would like to thank all the people who participated in sampling campaigns over more than 20 years.

Funding information

Data availability statement

Restrictions apply to the availability of discharge data, which were used under an agreement for this study. Fish and temperature data are available from the authors upon reasonable request.