DOI: 10.5061/dryad.w9ghx3fq3
title: Climate-driven dietary change on the Colorado Plateau, USA and implications for gender-specific foraging patterns

description: Complementary archaeological and paleoenvironmental datasets from North
 Creek Shelter (Colorado Plateau, Utah, USA) are analyzed using the diet
 breadth model, revealing human dietary patterns during the early and
 middle Holocene. Abundance indices are derived from botanical and faunal
 datasets and along with stone tools, are used to test the prediction that
 increasing aridity caused the decline of high-return resources. This
 prediction appears valid with respect to botanical resources, as
 high-ranked plants drop out of the diet after 9800 cal BP and replaced
 with low-ranked, small seeds. The prediction is not met, however, with
 respect to faunal resources: high-ranked artiodactyls are consistently
 abundant in the diet. The effects of climate change on dietary choices are
 also examined, finding that increased aridity coincides with greater use
 of small seeds and ground stone tools, but not with increases in
 low-ranked fauna, such as leporids. The patterns observed from the North
 Creek Shelter botanical and faunal datasets may reflect different foraging
 strategies between men and women, thus accounting for the discrepancy that
 low-ranked plant resources became increasingly abundant in the diet
 without a corresponding decrease in abundance of high-ranked artiodactyls.
 If so, then archaeological records with similar datasets should be
 re-examined with this perspective.
description: <i>Faunal Dietary
 Patterns</i> Faunal remains were recovered from a
 total of 53 substrata across strata II through VI.  Previous evaluations
 of NCS faunal remains did not properly account for taphonomy, thereby
 potentially including non-cultural taxa (e.g. carnivores and rodents) in
 analyses of diet breadth. This was avoided by using the annotated data
 records and segregating specimens into human and non-human accumulations
 based on burning and cut marks as cultural markers. Taxa were included
 using the lowest taxonomic category that could be assigned with
 confidence. Taxa represented by a single specimen in any given substratum
 were excluded in order to minimize the effects of an accidental movement
 of specimens across strata. <i>Botanical Dietary
 Patterns</i> Macrobotanical remains (e.g. seeds,
 seed coats, fruits) were recovered by flotation analysis from hearth
 features (n=156) excavated from 38 substrata spanning all cultural strata
 (II - VI). Identification of certain families is made possible by their
 diagnostic characteristics such as the thick, ovoid and large seed coats
 of Pinaceae or the angular, elongated and small achenes of Asteraceae.
 Certain genera are also identified in this way; for example, the
 lenticular, beaked and rimmed seeds of <i>Chenopodium. C.
 berlandieri</i> was isolated from all other
 <i>Chenopodium</i> spp. seeds because it has a distinctive
 reticulate pericarp and seed coat patterning (Holmgren et al. 2012). 
 <i>Rhus</i> sp. (sumac) seeds are ovoid with a radicle bulge
 (these specimens are distinctively striated, perhaps due to pericarp
 impression).  In three cases are materials identified to species,
 <i>Atriplex</i> <i>confertifolia
 </i>(shadscale)<i> </i>by its two-winged fruits,
 <i>Achnatherum hymenoides </i>(Indian ricegrass) by its
 distinctive flask-shaped achene, and <i>Solanum jamesii</i> by
 its distinctive starch granules (Louderback and Pavlik 2017). Unidentified
 and indeterminate seeds and fruit are not included in the dietary
 analyses. The lowest possible taxonomic level was determined by using
 contemporary reference material from herbaria, seed reference collections,
 as well as plant specimens gathered at the study site itself.
 Ninety-four ground stone tools spanning strata V and VI were
 analyzed for starch granules. The majority of tools were made from
 sandstone (88%), with quartzite (6%), volcanics (5%) and granite (1%)
 comprising the remainder. The weight of the tools varied from 4 grams to
 approximately 13.5 kilograms (see Louderback 2014 for ground stone
 inventory and data).<strong> </strong>Starch granules were
 extracted following the protocols outlined in Louderback (2014) and
 Louderback et al. (2015) and<strong> </strong>granules were
 identified using the approached outlined in Louderback et al. (2017). Only
 starch granules with eccentric hila have been positively identified
 (Louderback and Pavlik 2017). Because there is no way to determine an
 absolute count of starch granules, NISP is based on the number of ground
 stone tools that yielded identifiable granules in each substratum. For
 example, in substratum Vt, three of the twenty ground stone tools bore
 granules assigned to <i>Solanum jamesii</i> and, therefore,
 the NISP value for <i>S. jamesii</i> in substratum Vt is
 three.