Four millennia of long-term individual foraging site fidelity in a highly migratory marine predator

Deep antiquity of seagrasses supporting European eel fisheries in the western Baltic

Protecting ocean habitats is critical for international efforts to mitigate climate impacts and ensure food security, but the ecological data upon which policy makers base conservation and restoration targets often reflect ecosystems that have already been deeply impacted by anthropogenic change. The archaeological record is a biomolecular archive offering a temporal scope that cannot be gathered from historical records or contemporary fieldwork. Insights from biogeochemical and osteometric analyses of fish bones, combined with context from contemporary field studies, show how prehistoric fisheries in the western Baltic relied on seagrass meadows. European eels (Anguilla anguilla) harvested by Mesolithic and Neolithic peoples over millennia showed a strong fidelity for eelgrass foraging habitats, an ecological relationship that remains largely overlooked today, demonstrating the value of protecting these habitats. These data open new windows onto ecosystem- and species-level behaviours, highlighting the need for wider incorporation of archaeological data in strategies for protecting our oceans.

Archaeological evidence for long-term human impacts on sea turtle foraging behaviour

Early conservation efforts to prevent the loss of green sea turtles (Chelonia mydas) from the Caribbean Sea jumpstarted marine habitat and biodiversity protection. However, even there, limitations on historical observations of turtle ecology have hampered efforts to contextualize foraging behaviours for conservation management. We integrate isotopic and zooarchaeological evidence from green sea turtles harvested at the Miskito Cays (Nicaragua) to assess foraging behaviour before and after a step change in harvesting intensity. Highly structured isotopic evidence shows greater foraging adaptability in earlier populations. This provides a counterpoint to recent synthesis, suggesting the ecological non-exchangeability of sea turtles, which complicates conservation planning focused on genetic-stock-based repopulation. In contrast, our results suggest future populations would have a capacity for higher degrees of ecological exchangeability than current perspectives allow. This highlights a need to consider the kinds of longer term perspectives, such as those offered by archaeological materials, when planning for future sea turtle recovery.

The ratting of North America: A 350-year retrospective on Rattus species compositions and competition

While the impacts of black (Rattus rattus) and brown (Rattus norvegicus) rats on human society are well documented-including the spread of disease, broad-scale environmental destruction, and billions spent annually on animal control-little is known about their ecology and behavior in urban areas due to the challenges of studying animals in city environments. We use isotopic and ZooMS analysis of archaeological (1550s-1900 CE) rat remains from eastern North America to provide a large-scale framework for species arrival, interspecific competition, and dietary ecology. Brown rats arrived earlier than expected and rapidly outcompeted black rats in coastal urban areas. This replacement happened despite evidence that the two species occupy different trophic positions. Findings include the earliest molecularly confirmed brown rat in the Americas and show a deep ecological structure to how rats exploit human-structured areas, with implications for understanding urban zoonosis, rat management, and ecosystem planning as well as broader themes of rat dispersal, phylogeny, evolutionary ecology, and climate impacts.

Documenting the short-tailed albatross (Phoebastria albatrus) clades historically present in British Columbia, Canada, through ancient DNA analysis of archaeological specimens

The short-tailed albatross (Phoebastria albatrus) is a threatened seabird whose present-day range encompasses much of the North Pacific. Within this species, there are two genetic clades (Clades 1 and 2) that have distinctive morphologies and foraging ecologies. Due to a global population collapse in the late 19th and early 20th centuries, the frequency of these clades among the short-tailed albatross population that historically foraged off British Columbia, Canada, is unclear. To document the species' historical genetic structure in British Columbia, we applied ancient DNA (aDNA) analysis to 51 archaeological short-tailed albatross specimens from the Yuquot site (Borden site number: DjSp-1) that span the past four millennia. We obtained a 141 bp cytochrome b sequence from 43 of the 51 (84.3%) analyzed specimens. Analyses of these sequences indicate 40 of the specimens belong to Clade 1, while 2 belong to Clade 2. We also identified a single specimen with a novel cytochrome b haplotype. Our results indicate that during the past four millennia most of the short-tailed albatrosses foraging near Yuquot belonged to Clade 1, while individuals from other lineages made more limited use of the area. Comparisons with the results of previous aDNA analyses of archaeological albatrosses from Japanese sites suggest the distribution of Clades 1 and 2 differed. While both albatross clades foraged extensively in the Northwest Pacific, Clade 1 albatrosses appear to have foraged along the west coast of Vancouver Island to a greater extent. Due to their differing distributions, these clades may be exposed to different threats.