Metabarcoding-based assessment of fecal eukaryotic communities and parasite reservoir potential of Black-tailed Gulls at the urban coastal interface in South Korea
Understanding how environmental interfaces shape pathogen circulation is important for advancing One Health approaches in rapidly urbanizing coastal regions. Seabirds exploiting anthropogenic resources can link marine, terrestrial, and human-associated environments, potentially contributing to parasite dissemination. The occurrence of trematodes requiring aquatic intermediate hosts is consistent with exposure to coastal environments supporting complex parasite life cycles. Correlation analysis based on centered log ratio transformation revealed structured co-occurrence patterns, with predominantly negative associations between dominant fungal taxa and helminths. Although regional differences in prevalence were not statistically significant, spatial variability in detection patterns suggests heterogeneity in local environmental conditions and anthropogenic influences. These findings highlight urban adapted seabirds as environmental sentinels and provide baseline data on parasite diversity in coastal ecosystems. Wildlife-derived metabarcoding may support future environmental surveillance and improve understanding of exposure risks at the human environment interface.