Reconstructing the childhood diet of individuals buried with the Pictish monastic community at Portmahomack

2021 ◽  
Vol 150 ◽  
pp. 385-406
Author(s):  
Jyoti Stuart-Lawson ◽  
Shirley Curtis-Summers

This research aims to reconstruct the childhood diets (aged 9–10 years) of the individuals buried during the active years of the Pictish monastic community (hereafter referred to as PMC) from early medieval (7th–11th century) Portmahomack in north-east Scotland, using 13C and 15N isotopes. Dietary reconstructions were achieved by isotope analysis of δ13C and δ15N on the tooth root apex from permanent first molars (M1) of 26 adult male individuals. The results indicate that the indi-viduals in PMC predominantly consumed terrestrial C3 resources during childhood, with a rich terrestrial protein diet and some marine resource consumption. Statistically significant differences were observed between childhood and adulthood diets (the latter derived from previous research), suggesting that when these individuals were children, they consumed more marine protein than in later years as adults. This is true for all individuals, whether or not they spent significant time in Portmahomack during their childhoods. This is the most extensive study of the childhood diet of in-dividuals from the PMC and so makes a significant contribution to augmenting information on diet and lifestyles in Pictish Scotland.

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 482
Author(s):  
Won Young Lee ◽  
Seongseop Park ◽  
Kil Won Kim ◽  
Jeong-Hoon Kim ◽  
Jong-Ku Gal ◽  
...  

Theory predicts that sympatric predators compete for food under conditions of limited resources. Competition would occur even within the same species, between neighboring populations, because of overlapping foraging habits. Thus, neighboring populations of the same species are hypothesized to face strong competition. To test the hypothesis that intra-specific competition is more intense than inter-specific competition owing to a lack of niche partitioning, we estimated the foraging area and diving depths of two colonial seabird species at two neighboring colonies. Using GPS and time-depth recorders, we tracked foraging space use of sympatric breeding Chinstrap and Gentoo penguins at Ardley Island (AI) and Narębski Point (NP) at King George Island, Antarctica. GPS tracks showed that there was a larger overlap in the foraging areas between the two species than within each species. In dive parameters, Gentoo penguins performed deeper and longer dives than Chinstrap penguins at the same colonies. At the colony level, Gentoo penguins from NP undertook deeper and longer dives than those at AI, whereas Chinstrap penguins did not show such intra-specific differences in dives. Stable isotope analysis of δ13C and δ15N isotopes in blood demonstrated both inter- and intra-specific differences. Both species of penguin at AI exhibited higher δ13C and δ15N values than those at NP, and in both locations, Gentoo penguins had higher δ13C and lower δ15N values than Chinstrap penguins. Isotopic niches showed that there were lower inter-specific overlaps than intra-specific overlaps. This suggests that, despite the low intra-specific spatial overlap, diets of conspecifics from different colonies remained more similar, resulting in the higher isotopic niche overlaps. Collectively, our results support the hypothesis that intra-specific competition is higher than inter-specific competition, leading to spatial segregation of the neighboring populations of the same species.


2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.


2019 ◽  
Vol 76 (12) ◽  
pp. 2326-2331
Author(s):  
Nathan Wolf ◽  
Sarah R. Webster ◽  
Jeffery M. Welker ◽  
Bradley P. Harris

The ecological mechanisms driving an observed decline in the mean size-at-age of adult Pacific halibut (Hippoglossus stenolepis) in the eastern North Pacific Ocean have yet to be defined. Here, we present the results of a study designed to investigate the relationship between one potential mechanism — diet — and size-at-age using carbon and nitrogen stable isotope analysis. Our results indicate significant differences in the skeletal muscle δ13C and δ15N values between size-at-age categories for each sex, with larger-size-at-age fish consuming diets with higher δ15N values, indicating higher trophic level feeding. Analysis of Bayesian standard ellipse areas showed that for females, intermediate size-at-age categories have the largest dietary range. For males, the largest dietary range was observed in the largest size-at-age category. Our results suggest a size-based stratification in dietary strategy for Pacific halibut with implications for observed declines in size-at-age.


2020 ◽  
Vol 118 ◽  
pp. 105140 ◽  
Author(s):  
Magdalena Blanz ◽  
Ingrid Mainland ◽  
Michael Richards ◽  
Marie Balasse ◽  
Philippa Ascough ◽  
...  

2020 ◽  
Vol 13 (1-2) ◽  
pp. 10-17
Author(s):  
Young-Min Moon ◽  
Kwanmok Kim ◽  
Jinhan Kim ◽  
Hwajung Kim ◽  
Jeong-Chil Yoo

Stable isotopes are well documented as effective intrinsic markers to infer migratory connectivity which provides key information for establishing an effective conservation strategy in migratory birds. However, there are few studies using stable isotopes that have been applied to long-distance migratory shorebirds globally and such studies are especially scarce along the East Asian–Australasian Flyway. We used stable isotope analysis (δ2H, δ13C and δ15N) to infer breeding and wintering areas and examine the differences in those values among populations of Terek Sandpipers ( Xenus cinereus) at stopover sites in South Korea. The range of δ2H in feathers sampled from birds caught in the Korean peninsula at spring and autumn migration stopover sites was consistent with them being grown at sites throughout their flyway as confirmed by leg flag resightings of birds on this flyway. The eastern Siberia region from Yakutsk to Norilsk and Chukotka in Russia was inferred as the most probable breeding area of the population. Papua New Guinea in the Melanesia region, Malaysia and Indonesia were identified as the most probable wintering areas. Isotope values of populations at different stopover sites and different seasons were consistent. These results suggest that stable isotopes can be effectively used alongside other existing methods (e.g. ringing, coloured leg flags, light level geolocation, satellite tag telemetry) to infer the migratory connectivity for long-distance migratory shorebird species that occur over many countries and continents.


2016 ◽  
Vol 67 (8) ◽  
pp. 1196 ◽  
Author(s):  
Melissa Klamt ◽  
Jenny A. Davis ◽  
Ross M. Thompson ◽  
Richard Marchant ◽  
Tom R. Grant

The unique Australian monotreme, the platypus (Ornithorhynchus anatinus) potentially exerts a strong top-down influence on riverine food webs in eastern Australia. However, despite considerable interest in the evolutionary history and physiology of the platypus, little is known of its trophic relationships. To address this lack of knowledge we used stable isotope analysis, in combination with the analysis of food items stored in cheek pouches, to determine its position in a typical riverine food web. This was the essential first step in the process of designing a larger study to investigate the relative importance of top-down and bottom-up effects in rivers where the platypus occurs. We found that platypuses were feeding on a wide range of benthic invertebrates, particularly insect larvae. The similarity of δ13C and δ15N values recorded for the platypus, a native fish (Galaxias sp.) and the exotic mosquitofish (Gambusia holbrooki) indicated dietary overlap and potential competition for the same resources. Although cheek pouch studies identify most of the major groups of prey organisms, the potential for contribution of the soft-bodied organisms such as larval dipterans, is suggested by stable isotope analysis, indicating that the use of both techniques will be important in future ecological investigations.


Author(s):  
Sandra Berenice Hernández-Aguilar ◽  
Ofelia Escobar-Sánchez ◽  
Felipe Galván-Magaña ◽  
Leonardo Andrés Abitia-Cárdenas

Occupying the upper levels of trophic webs and thus regulating prey at lower levels, sharks play an important role in the trophic structure and energy dynamics of marine ecosystems. In recent years, the removal of these individuals from upper trophic levels as a result of overfishing has negatively affected ecosystems. We analysed the diet of blue sharks (Prionace glauca) caught off the west coast of Baja California Sur, Mexico, during the months of February–June in 2001, 2005 and 2006. We employed both stomach content and stable isotope analyses as each method provides distinct yet important information regarding the role of blue sharks in marine food webs, allowing us to estimate the relative contribution of different prey items to this predator's diet. Of the 368 stomachs analysed, 210 contained food (57%) and 158 (43%) were empty. Based on stomach contents and the index of relative importance (IRI), the pelagic red crab (Pleuroncodes planipes) was the most important prey, followed by the squids Gonatus californiensis (34.1%) and Ancistrocheirus lesueurii (10.4%). The mean (±SD) values for δ15N (16.48 ± 0.94‰) and δ13C (−18.48 ± 0.63‰) suggest that blue sharks prefer feeding in oceanic waters. The trophic level based on stomach content analysis was 4.05, while that based on the stable isotope analysis was 3.8, making blue sharks top consumers in the marine ecosystem of Baja California Sur, Mexico.


2016 ◽  
Vol 99 (4) ◽  
pp. 1032-1037
Author(s):  
Feng M Sun ◽  
Guang Y Shi ◽  
Hui W Wang

Abstract Consumers prefer natural and healthy food, but artificial pigments are often abused in egg products. The study aimed at differentiating the origin of pigments in eggs by applying the technique of carbon (13C/12C) and nitrogen (15N/14N) stable isotope analysis. Five hundred sixty laying hens were randomly distributed into 14 treatments, which were divided into four groups: maize, carophyll red pigment, carophyll yellow pigment, and a mixture of carophyll red and yellow pigments. Eggs were collected and pretreated to determe the values of the Roche Yolk Color Fan (RCF), δ13C, and δ15N. With increasing maize content, the RCF and δ13C values of yolks increased. Moreover, the RCF values in the three pigment groups were significantly influenced by the artificial colors, but δ13C values were not significantly different, regardless of the existence of pigment. The δ15N values in all treatments did not vary as regularly as the carbon stable isotope. A strong positive correlation was found between RCF and δ13C in the maize group, but no such correlation was be observed in the pigment groups. It is concluded that carbon stable isotope ratio analysis (δ13C) of the yolk can be used to differentiate the origin of the pigment added to eggs.


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