@article{10902/28169, year = {2023}, month = {2}, url = {https://hdl.handle.net/10902/28169}, abstract = {Freshwater ecosystems are among the most threatened ecosystems on Earth. Effective conservation strategies are essential to reverse this trend and should be based on sound knowledge of biodiversity patterns and the main drivers structuring them. In this study, we investigated the role of environmental and dispersal-connectivity controls on freshwater diatom and fish communities? variability. We used 441 biological samples obtained from Spanish biomonitoring datasets, which cover a highly variable environmental gradient across the national river network. We compared the taxonomic and trait-based spatial dependency of the two biotic groups using distance-decay relationships and variation partitioning with spatially constrained randomisations. Our findings showed that most of the diatoms and fish biological variation was attributed to pure spatial and spatially structured environmental variation. Compared to diatoms, fish community composition presented a stronger spatial dependency, likely because of their weaker dispersal ability. In addition, broad-scale environmental characteristics showed a higher predictive capacity for fish assemblages? variation. Trait-based similarities presented lower spatial dependency than taxonomic datasets, indicating that they are less susceptible to dispersal-connectivity effects. These findings contribute to understand the mechanisms underlying river community assembly at large spatial scales (i.e., at and beyond the river network) and point out the importance of dispersal-connectivity processes, which are usually neglected in traditional niche-based biomonitoring programmes but can influence their outcomes (e.g., masking the detection of anthropogenic impacts). Therefore, the integration of the dispersal-connectivity component, as well as information on organisms? dispersal abilities, are crucial when establishing effective conservation objectives and designing biomonitoring strategies.}, organization = {Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No 765553 and from the project “WATERLANDS”, code PID2019-107085RB-I00, funded by MCIN/AEI/10.13039/501100011033/ and by ERDF “A way of making Europe}, publisher = {Springer}, publisher = {Biodiversity and Conservation 2023,32,589-607}, title = {Large-scale spatial patterns of riverine communities: niche versus geographical distance}, author = {Rocha Pompeu, Cassia and Peñas Silva, Francisco Jesús and Barquín Ortiz, José}, }