Polar ecosystems harbour a unique cold-adapted biodiversity that is threatened by rapid environmental change and increasing anthropogenic impact. In this context, collecting data on connectivity between populations is essential for supporting conservation management of living resources and ecosystems. Genetic connectivity is the extent to which populations in different parts of a species' geographical range are linked by the exchange of larvae, juveniles or adults (which are the vectors of genetic material). In the Southern Ocean, several Marine Protected Areas (MPAs) – large areas where human activities are restricted or prohibited to promote conservation – are established or under negotiations. Such MPAs are most effective if implemented as a network that considers genetic diversity and connectivity within and between species. In the present study, 607 individuals of ten Trematomus species were sequenced using reduced representation sequencing techniques. Thousands of genomic variants were used to investigate inter- and intraspecific patterns of divergence and connectivity across the Southern Ocean shelf. Population structure analyses of four different species (T. loennbergii, T. eulepidotus, T. scotti and T. newnesi) suggest long- range dispersal across the Weddell Sea and even along the entire West Antarctic coast that might be facilitated by the Weddell Sea Gyre and Antarctic Coastal current. A genetic break at the level of the Filchner Trough was observed in several species. The strong outflow from the Filchner-Ronne ice shelf may separate the trough area from the remaining Weddell Sea habitat. Finally, results suggest that previously undetected cryptic species may be present within both T. eulepidotus and T. loennbergii. Altogether, the present results contribute to the assessment of diversity and connectivity on the Southern Ocean shelf, which is imperative in view of unprecedented global change.
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RBINS Staff Publications 2024
Bioarchaeological studies of ancient wild and domestic animals provide critical insights into animal translocation and human-animal relationships over time. Domestic cats (Felis catus), in particular, have a long history of association with humans as companions and pest controllers. This makes them valuable bio-proxies for reconstructing human movements via sea and land routes, as well as dietary shifts in the anthropogenic niche. In this study, we performed genomic and stable isotope analyses on over 90 cat remains from two major trade hubs in northern Germany: the Viking settlement of Haithabu (AD 800 - 1050) and its medieval successor, the town of Schleswig (AD 1050 - 1250). Ancient DNA analysis showed no clear geographical pattern in mitochondrial DNA ancestries from the two sites, all of which belong to clade IV of F. s. lybica and are assigned to haplogroups A, C, and D. This likely reflects the widespread dispersal of domestic cats in Europe starting from the Roman era. Nuclear DNA analysis revealed limited gene flow from European wildcats, consistent with previous findings on ancient domestic cats from other regions in Europe. Stable carbon (δ13C µ = -19.1 ± 0.7‰) and nitrogen (δ15N µ = 10.5 ± 1.1‰) isotope ratio analysis of cats from both sites indicates that most cats had mixed diets involving some marine foods supplied by or scavenged from humans. This multidisciplinary approach enables a comprehensive reconstruction of human-mediated cat dispersals and their dietary patterns during pivotal socio-economic transformation.
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RBINS Staff Publications 2025
