Fig 1.
Location of Yuzhniy Oleniy Ostrov and northeast Baltic sites mentioned in the text with site detail.
A) Detail of the location of Yuzhniy Oleniy Ostrov with (B) showing the site and others in a wider geographical context [51], with C) showing a map of the Yuzhniy Oleniy Ostrov site with sampled burials highlighted. The site map was created using Natural Earth public domain data [52].
Table 1.
Summary of the archaeological human data currently available for each type of analysis. The numbers in brackets refer to sex identification based on osteology only (for details see SI3, Table S1-2 in S1 Data).
Fig 2.
Summary of available δ13Ccol and δ15Ncol data from YOO and Lake Onega.
Human (black circles) and faunal (symbols) values from YOO are plotted in front of 65% ellipses for freshwater fish (blue), reindeer (red) and other terrestrial animals (green) from the wider geographic supra-region included in dietary model 2 (see SI3, Table S3 in S1 Data for all baseline isotope values included). YOO faunal values, except for reindeer, modified from Schulting et al. [1] including a different (+2‰) adjustment for changes in δ13C value of atmospheric CO2 of modern data. One reindeer is likely affected by a suckling effect (1). Perch samples were omitted from dietary modelling due to anomalous values, except for one individual that was also sampled for CSIA (2) to facilitate comparison between CSIA and bulk collagen isotope values.
Table 2.
Comparison of results for the different applied FRUITS dietary mixing models. Estimated contributions of source fractions to the complete diet and protein portion, respectively, according to FRUITS models based on the average δ13Ccol, δ15Ncol and δ13Capa values at YOO and varying according to the inclusion of either game/fish values only from Lake Onega (1.1, 2.1) or from a broader geographical range including Finland and north-western Russia in the source values (1.2, 2.2), and to varying TEF values for δ15Ncol (a = 5.5‰, b = 4.6‰, c = 3.6‰).
Fig 3.
Summary of results of applied FRUITS dietary mixing models for multiple individuals from YOO.
Estimated dietary proportion of fish, game and plants to the YOO diet for mean values (first value in graph A-C) and the ten individuals for which apatite δ13C values were available. A) Model 1.2a indicating estimated contribution of different food sources to bulk dietary intake. B) Contribution of protein based on model 1.2a using combined collagen and apatite measurements. C) Estimated contribution of protein based on model 2.2a only using collagen data shown for the same eleven individuals represented in A and B. D) Contribution of protein based on δ13Ccol and δ15Ncol summarized for the complete data set.
Fig 4.
Overview of δ13Ccol and δ15Ncol values from YOO and other HGF sites in the northeast Baltic.
A) δ13Ccol and δ15Ncol values from YOO and other archaeological HGF sites (65% confidence for ellipses, separated for inland and coastal groups) focused on northeastern Europe clearly showing the unusually high δ15Ncol values of the YOO population compared to other boreal inland HGFs. Values from marine mammal hunters (Greenland and Hokkaido) and the Mesolithic of the Danubian Iron Gates region (Romania and Serbia) are included for comparative purposes [2,40,63,98,136–170]. B) Spatial distribution and sample size of the groups and sites included in A (for details see SI 2, Fig S8 in S1 File) [51]. The site map was created using Natural Earth public domain data [52].
Fig 5.
Overview of δ13Ccol, δ13Capa and δ13CAA used to assess origin of dietary sources at YOO.
A) The relationship between human δ13Capa and δ13Ccol values from YOO plotted against diet-specific regression lines after Froehle et al. [28] (following [186]). B-D) Bivariate plots of B) δ13CPhe vs. δ13CVal, C) δ13CLys vs. Δ 13CGly-Phe and D) δ13CLys vs. Δ13CVal-Phe, showing the values from YOO humans and Lake Onega fish compared with published data from humans and animals with known dietary background data (65% confidence ellipses) [35,40,42,132,139,169,187]. The perch with anomalous bulk δ13Ccol values (see Results) potentially associated with an altered feeding ecology is marked with an asterisk.
Fig 6.
δ15NGlx against δ15NPhe from collagen of YOO humans and Lake Onega fish.
The blue and brown dotted lines mark trophic position estimates in the aquatic (blue) and terrestrial (brown) food chain [78,98]. They, as well as the animal references from a global background [32,35,49,98,132,196,197] should be considered as guidelines only [78].
Fig 7.
Coefficient of variation for δ13C and δ15N values measured from HGF individuals from circum-Baltic sites.
Only sites with more than ten individuals analyzed are included (numbers refer to sample size). For Zvejnieki only HGF individuals are shown. For summary statistics see SI3, Table S7 in S1 Data.