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.

Macrophytes are a group of aquatic plants. They are at the base of the food chain and can provide a habitat for many other species. The relative abundance of different species is used to calculate an environmental quality index (IBMR). As part of the Sélune observatory, pilot stations have been set up along the main course of the Sélune, distributed from upstream to downstream of the hydroelectric dams. Three stations are located in the former reservoirs of the dams, while the other two, known as reference stations, are outside the area of influence of the former dams (one downstream, the other upstream). At these stations, aquatic biocenoses (including benthic macroinvertebrates, biofilms, macrophytes, etc.) are monitored. The parameters monitored are specific composition and cover, at 8 stations in the main course, located upstream, downstream and in neolotic areas of macrophyte communities. The monitoring frequency consists of one annual campaign for stations outside reservoirs (S0, S1 and S5) and two annual campaigns (spring/autumn) for neolotic stations (S2, S3.4, S4.1 and S6). The protocol used is the sampling protocol for macrophytes and bryophytes in accordance with standard NF T90-395 (October 2003), which defines the IBMR. Taxa are sampled for laboratory identification. This layer gives the value of the IBMR and EQR (normalized) index at a station for a campaign, as well as information concerning the robustness of this index, the quantities of taxa used to calculate these indices and also information in terms of the proportion of major floristic groups (heterotrophs, algae, bryophytes, pteridophytes, helophytes, phanerogrames, floating vegetation and submerged vegetation).

Microbial communities play a major role in the functioning of ecosystems: they are at the base of the food chain (primary production) and participate in the degradation of organic matter. These communities are also known to respond rapidly to environmental changes. Like macro-invertebrates, they can be used as ecological indicators. Benthic diatoms are the main photosynthetic organisms in this biological community. The relative abundance of the various species is used to calculate an environmental quality index (EQI). Major differences in communities between the upstream and downstream zones were observed when the dams were in place. These differences will change once the dams are removed. As part of the Sélune observatory, pilot stations have been set up along the main course of the Sélune, distributed from upstream to downstream of the hydroelectric dams. Three stations are located in the former reservoirs of the dams, while the other two, known as the reference stations, are outside the area of influence of the former dams (one downstream and the other upstream). At these stations, aquatic biocenoses (including benthic macroinvertebrates, biofilms, macrophytes, etc.) are monitored. Since September 2014, the stations are ideally sampled every month from April to October (7 annual surveys) using artificial substrates (glass slides placed in the water). In addition to the diatom survey (floristic list, IBD calculation), the chlorophyll-a concentration is measured. This layer shows the location of the study sectors used to monitor photosynthetic biofilms and the campaigns carried out.

As part of the Sélune observatory, pilot stations have been set up along the main course of the Sélune, distributed from upstream to downstream of the hydroelectric dams. Three stations are located in the former reservoirs of the dams, while the other two, known as the reference stations, are outside the area of influence of the former dams (one downstream and the other upstream). At these stations, aquatic biocenoses (including benthic macroinvertebrates, biofilms, macrophytes, etc.) are monitored. 2 sampling campaigns (spring and autumn) for benthic macroinvertebrates (bmi) have been carried out since September 2014. During each campaign, 2 sampling protocols are implemented: - in accordance with standard NF T90-333, which enables the calculation of the IBG-DCE and I2M2 (‘SURBER’) - via artificial substrates immersed for 1 month (‘SUBART’), in order to focus on measuring the ‘effect of dams’. The protocol is described in: Piscart C., Moreteau, J.C., Beisel J.N. (2006). Monitoring changes in freshwater macroinvertebrate communities along a salinity gradient using artificial substrates. Environmental Monitoring and Assessment 116: 529-542. This layer details the benthic macroinvertebrate taxa and their abundance obtained after analysis (according to standard NF T90-388). These data are distributed by campaign and by sector. Taxa presenting all the morphological criteria clearly visible and characteristic allowing the exactitude of their determination and an irreproachable state of conservation are integrated into the reference collection of the Sélune Observatory. This collection can be consulted on request (see contact point). Taxon determination is based on version v17 of the TAXREF reference. The dataset is currently under embargo.

As part of the Sélune observatory, pilot stations have been set up along the main course of the Sélune, distributed from upstream to downstream of the hydroelectric dams. Three stations are located in the former reservoirs of the dams, while the other two, known as the reference stations, are outside the area of influence of the former dams (one downstream and the other upstream). At these stations, aquatic biocenoses (including benthic macroinvertebrates, biofilms, macrophytes, etc.) are monitored. At each of these stations, benthic macroinvertebrates (bmi) have been sampled regularly, in spring and autumn, since September 2014 and in accordance with standard NF T 90-333. The fauna inventories obtained after determination can thus be used to calculate biotic indices such as the IBG-DCE and the I2M2. In addition, samples were taken using artificial substrates immersed for 1 month, in order to focus on measuring the ‘dam effect’. The protocol is described in: Piscart C., Moreteau, J.C., Beisel J.N. (2006). Monitoring changes in freshwater macroinvertebrate communities along a salinity gradient using artificial substrates. Environmental Monitoring and Assessment 116: 529-542. This layer gives the results obtained for the IBG-DCE and I2M2 biotic indices with the associated parameters (diversity, variety, etc.), as well as the number of samples taken (‘effort’ column). Finally, the layer contains the output from the ‘ODInvertebres’ diagnostic tool for benthic invertebrates, which aims to identify the most likely anthropogenic pressures causing changes in ecological quality (6 probability values for physico-chemical water quality and 6 others relating to hydromorphology or land use in the catchment area). Reference on ‘ODInvertebres’ : Mondy, C. P., & Usseglio-Polatera P. Using conditional tree forests and life history traits to assess specific risks of stream degradation under multiple pressure scenario. Science of the Total Environment 461 (2013): 750-760. The genus Baetis cited in the fauna lists refers to the genus ‘Baetis lato sensu’ according to the SANDRE nomenclature (Sandre code: 9794). Taxa presenting all of the clearly visible and characteristic morphological criteria enabling them to be accurately identified and in an irreproachable state of conservation are included in the Observatoire Sélune's reference collection. This can be consulted on request (see point of contact).