The Supporting ES provision is related with presence, abundance, diversity and functional traits of co-occurring biological groups (Lavorel et al., 2017). We aim to contribute to biodiversity process understanding by addressing the interactions of aquatic biota and riparian vegetation. This biotic realism can only be achieved with field data. We focus in three aquatic communities considered as biological quality elements by the EU-Water Framework Directive (2000/60/EC), namely diatoms (microalgae), macrophytes (aquatic and emergent plants, including macroalgae and bryophytes), and benthic invertebrates.

This activity is devoted to obtain field data from diatoms, macrophytes, benthic invertebrates and also riparian vegetation. Surveys will be carried out in river reaches downstream of dams and in free-flowing rivers. The field team will be sampling at the same time to ensure spatial and temporal similarity of data. Hydrogeomorphological and habitat characteristics will be also collected. Benthic invertebrates will be collected with a kick-net (opening 25 cm, 0.5 mm mesh). At each habitat (riffle, run, pool) three sub-samples will be collected covering each 1 * 0.25 m of sediment, pooled together preserved with formalin (10%). At the laboratory, invertebrates will be sorted and identified at least to genus level, to enable future traits analysis. Biofilm will be scraped from at least 100 cm2 of the upper surface of stones, using a hard brush (i.e., toothbrush). When substrates are absent, macrophytes will be squeezed and an epiphytic sample will be obtained. These samples will be preserved with formalin to a final concentration of about 10%. Identification to the lowest taxonomic rank possible (species rank) has taken place and enumeration (ca. 400 valves) will be completed under the light microscope. Macrophytes will be recorded in a 100-m section of the river and cover estimated. Surveys will be done by zigzagging across the channel. An additional downstream survey will be done to ensure that all species were recorded to confirm species abundance attributed in the first assessment. Riparian woody species (trees, shrubs, lianas) will be recorded as well as the foliage projective cover of each species. Identification mostly at species level.