Contextualizing the influence of climate and culture on bivalve populations: Donax obesulus malacology from the north coast of Peru

Abstract

Climate (in)stability can manifest in the size of mollusks attesting to variable impacts on growth, seasonal exploitation, and cultural persistence. We present population statistics of the height of a bivalve species (Donax obesulus) collected from sites dating to the Early Horizon (EH, 900–200 BCE) in the Nepeña Valley and the Middle Horizon (MH, 600–1000 CE) in the Jequetepeque Valley of northern coastal Peru and compare them with a paleoclimate record and a sample of modern shells (collected in 2012, 2014, and 2016) from the Nepeña Valley. We observe diachronic variation in the size of D. obesulus with larger bivalves during the EH and smaller shells during the MH and in the modern sample. D. obesulus size remains relatively static during the MH at one site through two sub-phases. These bivalve populations were likely impacted by both climate and cultural circumstances. A proxy for runoff from El Niño related rainfall (%lithic flux) from a previously published nearby marine sediment core is elevated during the EH and Late Moche phase of the MH and correlates with shell height. During the Transitional phase of the MH and the modern interval, however, there are periods of comparatively reduced El Niño activity and shell height compared to the EH.

Keywords:

• Northern Andes
• paleoclimate
• coastal
• fishing
• economy and subsistence

Acknowledgements

We thank David Chicoine, Kristine DeLong, and Edward Swenson for their guidance, feedback, and for access to collections. We would also like to thank the members of the Proyecto Investigación Arqueológico Caylán (PIAC) and the Proyecto de Investigación de Arqueología de Jatanca-Huaca Colorada (PIAJ-HC), the Ministerio de Cultura del Perú, the Department of Geography and Anthropology at Louisiana State University, and the Department of Anthropology at the University of Toronto. Giannina Bardles provided permission from the Larco Museum to use the image of a Moche vessel depicting donax. We finally thank the editor, Dr Giovas, and the three anonymous reviewers who provided thoughtful and thorough comments and suggested revisions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability

Shell data are to be archived with the Functional Trait Resource for Environmental Studies (https://futreswebsite.netlify.app/) project. Marine sediment core data are available from the original study author (Bert Rein, [email protected]) by request.

Additional information

Funding

Warner was supported by National Science Foundation (NSF) grant #1805702. Alaica was supported by the Social Sciences and Humanities Research Council (SSHRC) of Canada grant #752-2014-2431.