La densité de bâti est calculée par maille de 150 mètres de côté et sur la base d'une extraction du bâti à partir d'imagerie très haute résolution spatiale (1.5m) SPOT 6/7, pour les années 2015 à 2019.

The study of riparian vegetation is based on the observation of natural plant communities spontaneously colonizing newly exposed areas following the erasure of the Vezins and La-Roche-Qui-Boit dams. The vegetation monitoring system includes two complementary approaches: i) a vegetation sampling method based on floristic surveys (composition & structure) carried out within a series of quadrats positioned along a transect ii) a monitoring of the vegetation units (UV) observed within the valley This dataset specifically concerns the overall characterization observed on each quadrat in terms of strata and concerns only the Sélune Observatory (2021-2026). The sampling monitoring system is based on measurements distributed at different points in space (longitudinally and laterally). It aims to identify the diversity of flora and vegetation and describe the structure of emerging formations and plant communities within the neo-valley. Implemented annually (sub-annual only for 2021, before dismantling), this monitoring aims to identify and characterize the evolution trajectories of these vegetation over time. The vegetation sampling protocol is implemented at several stations located along the course of the Sélune and at the mouth of several tributaries located in the right-of-way of the two former reservoirs. The sample of stations is supplemented by a batch of stations positioned outside the right-of-way of the two former reservoirs, downstream and upstream, which constitute so-called "reference" stations. For each station, a transect is established perpendicular to the channel, from the bank to a reference point located at the level of the former water reservoir (i.e. 60m NGF for Vezins & 28.5m NGF for LRQB). Along this transect, 25m2 (5mx5m) quadrats are positioned according to previously set distance intervals. These quadrats (named Q1 to Q1+n) constitute the elementary unit within which abiotic (slope, texture...) and biotic (composition, structure) parameters are characterized and evaluated. The number of quadrats sampled per station varies depending on the width of the exposed bank (or transect length). It is completed by a reference quadrat, located beyond this maximum value (named Q0). The inventory of vascular flora, i.e. herbaceous and woody plant species within the quadrats, aims to be exhaustive and to identify them up to the specific or even sub-specific rank. The overall characterization mentioned mainly concerns, for each quadrat, the type of soil encountered (see attribute dictionary), the slope (see attribute dictionary), the proportions of water cover, bare soil, and litter, as well as, for each of the 6 defined strata (see attribute dictionary): the considered height limits, the maximum and average height, and the proportion of overlap (relative to the 25m2 of the quadrat). This layer gives, for each monitoring quadrat of vegetation sampling from 2021 to 2026, the following information: – Quadrat information (id, code, number and distance from its centroid to the station reference point), – Campaign information (id, code, date, campaign), – Station information (code, name, protocol applied, number of quadrats, code for the associated Sélune reference point and, as a result, positioning on the catchment area, distance to sea, distance to source and watercourse, watercourse reference altitude) – Information on the transect by campaign (number and length, X, Y, LON, LAT coordinates of the reference points “NGF” and end point “bank”) – Information concerning the strata (identified or not), soil typology, water, bare and litter coverings, as well as details for each stratum (name of stratum ‘muscinal’, “herbaceous”, “young plant shrub,” “low shrub', “high shrub” and “arborescent, the height limits of the stratum, the associated overlap, the maximum and average heights of the stratum) – “Point” geometry (default) corresponding to the transect reference point

Cette carte a été produite dans le cadre de la convention 2010 -- 0190 de l'Agence de l'Eau Rhône Méditerranée et Corse concernant l'optimisation d'une méthode de quantification du rôle des corridors rivulaires sur l'état écologique des cours d'eau.

The opening of the dams should impact the functioning of Atlantic salmon populations migrating up the Sélune River and its tributaries. Restoring the river's ecological continuity will alter population flows by allowing amphihaline sea trout to migrate further upstream and native trout to move downstream and upstream of the dams. The trout population is monitored at a network of stations covering the entire Sélune basin using an abundance index, which is carried out every two years before 2021 and every year since then. Field campaigns comply with the fishing protocol developed by INRAE and OFB. The aim of this method is to estimate the abundance of juvenile Atlantic salmon (Salmo salar) at a station (or sector). This protocol targets juveniles of the year (aged 0+) whose abundance reflects the renewal of generations within the population (or recruitment) and survival after the embryonic development phases under gravel and the first months of life in the open environment. Field campaigns are carried out by INRAE and the Manche d'Ille-et-Vilaine Federation for Fishing and the Protection of the Aquatic Environment (FDAPPMA50 and FDAAPPMA35). This dataset provides individual biometric data on Atlantic salmon caught during PAS fishing sessions in the Sélune watershed, by station and by fishing session.

Cette carte a été produite dans le cadre du projet FUI-2012 SIRHYUS (Services d'Information pour la gestion des Ressources HYdriques et de leurs USages) et a bénéficié d'une aide de l'Etat gérée par l'Agence Nationale de la Recherche au titre du Programme Investissements d'Avenir pour le projet EQUIPEX GEOSUD ANR-10-EQPX-20.

Les données de nodata par année (entre 2015 et 2019) correspondent aux zones de nuages et de leurs ombres portées sur les images satellites SPOT 6/7 utilisées pour la classification d'occupation du sol, donnée source pour les analyses géographiques qui ont suivi (extraction des espaces bâtis, des taches urbaines, indicateurs spatialisés)

Geodetic markers were installed along the main course of the Sélune. Physically marked out in the field, these markers have been located with a high-precision GPS (planimetric and z-precisions are given in the table). Please note that these markers may move slightly with the wetting/drying cycles of mainly clay soils, and their coordinates may be updated if necessary. Geodetic markers can be used as reference points to define a device or a new study area.