This project compares the implementation, acceptance, and progress of dam removal projects in France, using the example of the Sélune, and in the United States, where several similar removal projects have taken place.

This project assesses the impact of restoring connectivity between fish populations following the removal of dams on the Sélune River. It is based on the calculation of a genetic fragmentation index for five fish species. Data: - Genetic analysis and F-index

In a nutshell: The food web project takes a broad look at the aquatic communities found in the Sélune River, ranging from microorganisms to fish, in both its tributaries and the river itself, from its source to where it flows into the estuary. The approach aims to study the interactions between these biological components, with the primary objective of understanding the overall functioning of the ecosystem. The goal is to understand the balances within aquatic ecosystems, from the headwaters of the watershed to the lower reaches of the river, both before (current state) and after (river restoration) the restoration of continuity through the removal of dams. Objective: to answer the following questions: · What role do dams and their reservoirs play in shaping aquatic communities within the river and in the functioning of this ecosystem? · How does the river ecosystem recover at the exact location of a dam reservoir after it has been drained? · What roles do certain key species (particularly amphihaline fish and invasive species) play in ecological balances? · What consequences can be expected from dam removal operations, from the headwaters to the estuary entrance, on these communities and the functioning of the river ecosystem reconnected to the ocean? Methods: inventories; physicochemical characterization; functional ecosystem analysis; stable isotope analysis; food web analysis Data: - Measurements of water’s physicochemical quality - Community inventories - Estimation of (1) the degradation of coarse organic matter (tree leaf litter) via the detritus pathway, and (2) the photosynthetic activity of microorganisms and biofilms in the algal pathway. - Data from isotopic analyses of communities; identification of energy sources (food, carbon cycle) in food webs - Role of keystone species (invasive crayfish and fish predators) - Analysis of food web structure

Continuous monitoring stations for hydrological, physical, chemical, and sedimentary parameters have been installed on the Sélune River as part of the scientific program to monitor the removal of the Sélune dams. Measurements have been taken at least hourly since 2014. Since 2019, these stations have been under the responsibility of the Sélune Observatory, which is in charge of monitoring environmental parameters (biotic and abiotic). The physical and chemical parameters measured at all stations include turbidity, water level, and conductivity. At some stations, pH and dissolved oxygen or chlorophyll concentration are also measured. This layer provides raw measurements from the SIGNY, LA-ROCHE-QUI-BOIT, VIREY, and DORIERE (only until October 2020) hydrological measuring stations.

In a nutshell: This research project focuses on the social and geographical dimensions of the ecological restoration of the Sélune River. Its objective is to assess the current state of the landscapes, land uses, and practices in the Sélune Valley (and more specifically in the gorge section) prior to the removal of the dams, and then to monitor the changes brought about by the removal: the state of both material transformations (land use, practices, visitor traffic) and conceptual transformations (perceptions, discourse) of the territory in order to assess the impacts of this project and thereby measure its success from the users’ perspective (quality of life, regional development, practices, etc.) to understand, using the example of the Sélune, the difficulties in gaining acceptance and ownership of such a project by various local stakeholders, as well as the challenges related to its definition and implementation. Methods used: surveys, questionnaires, analysis of the local press, photography Data: - A collection of photographs (~40) covering the entire Sélune Valley to track changes in the landscape - Historical photographs and postcards. Photographs will be annotated and geotagged - Inventory of land uses (fishing, recreation, lodging, etc.), analysis of visitor traffic in the gorges, and mapping - Semi-structured interviews will be conducted with representatives of user groups (to gather their opinions) - Text analysis (using Alceste or WordMapper software) of transcribed interviews - Collection of residents’ opinions and assessment of their satisfaction with the project - Corpus of articles published in the regional daily press to track the history of reactions - Collection of information disseminated via other media platforms such as blogs, forums, and websites by various stakeholder groups, particularly fishermen, environmentalists, and opponents of the clearing - Codification of the corpus followed by a lexical and semantic analysis using the TXM platform

The aim of this project is to understand the exchanges between the groundwater and the water in the Sélune river. This knowledge will help prevent the physical, chemical, and biological changes that restoring continuity will cause to the water quality of the Sélune. Data: - water level records - temperature measurement records at various locations in the river sediments and in the piezometers - data from differential pressure sensors at certain points along the river, - data on the concentration of chemical elements (N, P, dissolved gases, etc.) in the sediments - fiber-optic data - Lidar campaign data Sites: At the start of the project, there are two main sites, each covering a few hundred meters, located nearby: - the Signy Bridge - the Biards Bridge Additional sites may be added later, if logistical constraints (such as the portability of certain measurement protocols) permit.

This project aims to develop and apply a non-invasive method for monitoring migratory fish flows in the Sélune River. The development of this method is based on the analysis of images and videos taken by a hydroacoustic camera positioned in the watercourse.

The goal of this project is to establish methods for monitoring the return of iconic migratory fish, such as salmon and eels, to the Sélune Valley following the restoration of its connectivity.

The opening of the dams will have a significant impact on fish populations in the Sélune. Restoring the river's ecological continuity will alter population flows by allowing certain amphihaline species to migrate further upstream and other species to move downstream and upstream of the dams. For more than 50 years, the API HUB'eau Poisson has been disseminating data collected during scientific electrofishing operations carried out by the French Office for Biodiversity (OFB) and its partners. This data concerns observations, indicators, operations, and sampling stations. It covers mainland France (including Corsica). It is stored in the Aspe tool operated by the OFB. The Poisson API provides access to almost all of the data in the Aspe management tool operated by the OFB. This tool is open to all producers who wish to store their fish data. For further information, please visit aspe.eaufrance.fr. Version 0 of the API, based on data from the former IMAGE database, is no longer accessible.