Helminths reveal long-term trophic simplification in owl communities

The helminth communities of owls may provide indirect information on host ecology and long-term changes in trophic interactions.We analyzed 645 owl specimens from 10 host species, collected in Central Europe between 1963 and 2026, to test for temporal changes in overall infection probability, helminth abundance and richness, host-dependent trajectories, and taxon-specific trends.In total, 22 helminth taxa were recorded, and 262 hosts (40.6%) were infected.The highest observed taxon richness occurred in Strix aluco (15 taxa) and Asio otus (10 taxa), which were also the most frequently sampled hosts.Analyses based on individual-host records showed significant long-term changes in community-level infection metrics and in several common helminth taxa.Cladotaenia globifera, Porrocaecum spirale, and Strigea strigis declined over time, whereas Centrorhynchus aluconis increased.The marked decline of S. strigis, a parasite linked to amphibian-mediated transmission pathways, suggests a long-term weakening of these trophic links.Temporal patterns differed among hosts, and the dominant taxa varied markedly among owl species.Synanthropic species, particularly Tyto alba and Athene noctua, showed comparatively depauperate helminth assemblages, consistent with reduced exposure to diverse prey-mediated transmission pathways.These results indicate that long-term change in owl helminth communities is https://doi.org/10.