From coast to interior: Trematodes completing freshwater life cycles are dominant in gulls recorded inland

Large gulls (Laridae) have expanded from coastal regions into inland Central Europe, where they increasingly exploit fishponds, landfills, and urban habitats.This shift alters their exposure to trematode parasites and their role in linking parasite transmission across ecosystems.We examined the trematode communities of five gull species (Larus argentatus, Larus cachinnans, Larus canus, Larus hyperboreus, and Larus marinus) collected in the eastern Czech Republic between 2022 and 2025.Complete helminthological examinations were performed on 207 individuals.Trematodes were detected in 82% of the birds, but the infection patterns differed among host species.Assemblages were overwhelmingly dominated by freshwater-transmitted taxa associated with cyprinid fish, particularly Diplostomum spp.and related genera.Pondforaging gulls (L.argentatus and L. cachinnans) presented high prevalence, richness, and infection intensity, with frequent coinfections indicating repeated exposure within freshwater food webs.In contrast, L. canus and landfill-associated birds were often uninfected or lightly infected, reflecting limited participation in aquatic transmission cycles.Marine and brackish