2026-10-07T02:52:30Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32346744 2026-09-28T09:10:36Z category_24217 category_24223 item_type_3 month_year_09_2026

Data from: Occupancy and niche dynamics of Iberian freshwater fish across twenty-five years Carlos Cano-Barbacil (6724640) Rafael Muñoz-Mas (6859958) Carmen Duque-Amado (23946168) Emili García-Berthou (9536108) Silvia Perea (12962063) Ignacio Doadrio (21670761) Community ecology (excl. invasive species ecology) Freshwater ecology Freshwater fish Global change Iberian Peninsula Outlying Mean Index Species niche Temporal analysis <p dir="ltr">Global change is reshaping biological communities, leading to shifts in community composition, species distributions and species realized niches. These processes are especially relevant in freshwater ecosystems, where vertebrate declines are particularly severe and dispersal is naturally constrained by drainage basins. Here, we investigated changes in freshwater fish species occupancy, realized niches, and their relationships with species traits across the Iberian Peninsula between two periods (2001–2010 and 2015–2024) using data from 204 sampling sites. We combined monitoring data, environmental variables, species traits, and complementary statistical approaches, including the within outlying mean index (WitOMI), an ordination method that quantifies niche metrics such as marginality and breadth while identifying the main environmental gradients structuring communities. No significant changes were detected in mean species occupancy or niche parameters between periods. However, this apparent stability masks species-specific dynamics. Increases in occupancy were observed in fast life-cycle species. Similarly, declines in niche marginality were predominantly associated with habitat generalists and species with low fecundity but with a long reproductive season; while changes in niche breadth were only weakly and negatively associated with omnivory and body elongation. Overall, our results suggest a modest reorganization of Iberian freshwater fish communities driven by the expansion of generalist species and declines in specialists. These trends are consistent with ongoing biotic homogenization and highlight the importance of integrating distributions, niche dynamics, and functional traits to understand biodiversity responses to global change.</p> 2026-09-28T09:10:36Z Dataset Dataset 10.6084/m9.figshare.32346744.v1 https://figshare.com/articles/dataset/Data_from_Occupancy_and_niche_dynamics_of_Iberian_freshwater_fish_across_twenty-five_years/32346744 CC BY 4.0