Using non-dietary gastropods in coastal shell middens to infer kelp and seagrass harvesting and paleoenvironmental conditions

Amira F Ainis,René L Vellanoweth,Queeny G Lapeña,Carol S Thornber

doi:10.1016/j.jas.2014.05.024

Amira F Ainis, René L Vellanoweth + Show 2 more

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https://doi.org/10.1016/j.jas.2014.05.024

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Abstract

Archaeologists analyzing shell middens typically focus on larger (>2 cm) mollusks to examine subsistence practices, impacts on littoral habitats, and paleoenvironmental conditions as well as a host of other natural and cultural phenomena. Small (<2 cm), non-dietary gastropods in archaeological shell middens also provide important clues regarding human resource procurement in littoral areas and coastal paleoenvironments. We present data from two sites on the California Channel Islands to demonstrate the range of information that can be gained by analyzing small gastropod shells. Identifications revealed the remains of over 4500 non-dietary small gastropods from 75 taxa. Human harvesting of marine macrophytes is suggested by the presence of 18 species that are predominantly associated with seaweeds and seagrasses. Quantification measures revealed high diversity and equitability indices, oscillating taxonomic richness, and decreasing densities through time at both sites. Likelihood ratio tests revealed differences in assemblage composition between Early Holocene and later components at one site, and demonstrated similarities in the relative composition of non-dietary shell assemblages between both sites during the Middle Holocene. Incorporating detailed studies of less conspicuous “incidental” shellfish remains in archaeological midden studies has the potential to contribute to our understanding of past human land use practices and littoral paleoecology. Our findings are applicable to archaeologists working in coastal settings around the world, as well as marine ecologists interested in intertidal paleo-habitats and kelp forest ecosystems.

Highlights

Small, non-dietary shells are accidentally incorporated in archaeological middens through a variety of mechanisms, and can provide significant information through their associations with purposely harvested perishable resources such as marine algae and plants
A total of 4,568 individuals belonging to 34 genera and 61 species of small gastropods was identified in this study, excluding larger shellfish taxa known to be of dietary value
Analysis of small gastropods from Cave of the Chimneys resulted in the identification of 3,305 individuals belonging to 28 genera and 49 species (Table 5), with seaweed and seagrass associates comprising close to 26% of the minimum number of individuals (MNI) of small gastropods

Summary

Introduction

Non-dietary shells are accidentally incorporated in archaeological middens through a variety of mechanisms (see Claassen 1998; Stiner 1999), and can provide significant information through their associations with purposely harvested perishable resources such as marine algae and plants. Substantial and varied uses of seaweeds and seagrasses by Native People have been extensively documented for the Pacific Northwest Coast of North American and the Gulf of California. Several marine macroalgae, including sea wrack (Fucus gardneri, Fucus sp.), giant kelp (Macrocystis pyrifera), bull kelp (Nereocystis leutkeana), and red lavers (Porphyra spp.) were (and in some cases still are) utilized by Native Peoples of the Pacific Northwest Coast (Ager and Ager 1980; Turner 1995, 2003; Turner and Bell 1973). Kelp blades were used as heated poultices and the long hollow tubular stipes were used to store oil and grease and to make ropes, fishing nets and lines, and harpoon lines (Turner and Bell 1973)

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