Integrating archaeology and ancient DNA analysis to address invasive species colonization in the Gulf of Alaska

• Published in: Conservation biology 2017-10, Vol.31 (5), p.1163-1172
• Main Authors: West, Catherine, Hofman, Courtney A., Ebbert, Steve, Martin, John, Shirazi, Sabrina, Dunning, Samantha, Maldonado, Jesus E.
• Format: Article
• Language: English
• Subjects: Alaska; ancient translocation; Animals; Aquatic birds; Archaeology; ardilla terrestre; Bones; Colonization; Conservation of Natural Resources; Deoxyribonucleic acid; Dispersal; Dispersion; DNA; DNA, Ancient; Ecosystems; ground squirrel; Ground squirrels; History; Humans; Introduced Species; Invasive species; invasive species management; Islands; Landscape; Lines; Mammals; manejo de especies invasoras; Marinas; Mitochondria; Nonnative species; Plants (botany); Polar environments; Prehistoric era; Radiocarbon dating; Radiometric dating; Sciuridae; Seabirds; Settlers; Species; Species classification; Squirrels; translocación antigua; Translocation; Urocitellus parryii; zooarchaeology; zooarqueología
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/cobi.12865

The intentional and unintentional movement of plants and animals by humans has transformed ecosystems and landscapes globally. Assessing when and how a species was introduced are central to managing these transformed landscapes, particularly in island environments. In the Gulf of Alaska, there is considerable interest in the history of mammal introductions and rehabilitating Gulf of Alaska island environments by eradicating mammals classified as invasive species. The Arctic ground squirrel (Urocitellus parryii) is of concern because it affects vegetation and seabirds on Gulf of Alaska islands. This animal is assumed to have been introduced by historic settlers; however, ground squirrel remains in the prehistoric archaeological record of Chirikof Island, Alaska, challenge this timeline and suggest they colonized the islands long ago. We used 3 lines of evidence to address this problem: direct radiocarbon dating of archaeological squirrel remains; evidence of prehistoric human use of squirrels; and ancient DNA analysis of dated squirrel remains. Chirikof squirrels dated to at least 2000 years ago, and cut marks on squirrel bones suggested prehistoric use by people. Ancient squirrels also shared a mitochondrial haplotype with modern Chirikof squirrels. These results suggest that squirrels have been on Chirikof longer than previously assumed and that the current population of squirrels is closely related to the ancient population. Thus, it appears ground squirrels are not a recent, human-mediated introduction and may have colonized the island via a natural dispersal event or an ancient human translocation. El movimiento intencional y no intencional de plantas y animales causado por los humanos ha transformado a ecosistemas y paisajes a nivel mundial. Valorar cuándo y cómo una especiefue introducida es importante para el manejo de estos paisajes transformados, en particular en los ambientes isleños. En el Golfo de Alaska hay un interés considerable por la historia de las introducciones de mamíferos y la rehabilitación de los ambientes isleños del Golfo de Alaska por medio de la erradicación de mamíferos clasificados como especies invasoras. La ardilla terrestre del Ártico (Urocitellus parryii) es de interés porque afecta a la vegetación y las aves marinas en las islas del Golfo de Alaska. Se asume que este animal fue introducido por los colonizadores históricos; sin embargo, los restos de ardillas terrestres en el registro arqueológico prehistórico de la Isla C