Radiocarbon and stable isotope evidence of dietary change from the Mesolithic to the Middle Ages in the iron gates: New results from Lepenski Vir

A previous radiocarbon dating and stable isotope study of directly associated ungulate and human bone samples from Late Mesolithic burials at Schela Cladovei in Romania established that there is a freshwater reservoir effect of approximately 500 yr in the Iron Gates reach of the Danube River valley in southeast Europe. Using the delta(15)N values as an indicator of the percentage of freshwater protein in the human diet, the C-14 data for 24 skeletons from the site of Lepenski Vir were corrected for this reservoir effect. The results of the paired C-14 and stable isotope measurements provide evidence of substantial dietary change over the period from about 9000 BP to about 300 BR The data from the Early Mesolithic to the Chalcolithic are consistent with a 2-component dietary system, where the linear plot of isotopic values reflects mixing between the 2 end-members to differing degrees. Typically, the individuals of Mesolithic age have much heavier delta(15)N signals and slightly heavier delta(13)C, while individuals of Early Neolithic and Chalcolithic age have lighter delta(15)N and delta(13)C values. Contrary to our earlier suggestion, there is no evidence of a substantial population that had a transitional diet midway between those that were characteristic of the Mesolithic and Neolithic. However, several individuals with "Final Mesolithic" C-14 ages show delta(15)N and delta(13)C values that are similar to the Neolithic dietary pattern. Provisionally, these are interpreted either as incomers who originated in early farming communities outside the Iron Gates region or as indigenous individuals representing the earliest Neolithic of the Iron Gates. The results from Roman and Medieval age burials show a deviation from the linear function, suggesting the presence of a new major dietary component containing isotopically heavier carbon. This is interpreted as a consequence of the introduction of millet into the human food chain

A freshwater diet-derived C-14 reservoir effect at the Stone Age sites in the Iron Gates gorge

Human bones from single inhumation burials and artifacts made from terrestrial mammal (ungulate) bone found in direct association with the skeletons were obtained from the Stone Age site of Schela Cladovei situated just below the iron Gates Gorge of the River Danube. The results of stable isotope analyses of the human bone collagen are consistent with a heavy dependence on aquatic protein while radiocarbon dating of the samples reveals an offset of 300-500 years between the two sample types, indicating a freshwater reservoir effect in the human bone samples, Since protein consumption is by far the major source of nitrogen in the human diet we have assumed a linear relationship between delta(15)N and the level of aquatic protein in each individual's diet and derived a calibration for C-14 age offset versus delta(15)N which has been applied to a series of results from the site at Lepenski Vir within the gorge, The corrected C-14 ages (7310-6720 BP) are now consistent with the previous C-14 age measurements made on charcoal from related contexts (7360-6560 BP). In addition, the data indicate a change from a primarily aquatic to a mixed terrestrial/aquatic diet around 7100 BP and this may be argued as supporting a shift from Mesolithic to Neolithic. This study also has wider implications for the accurate dating of human bone samples when the possibility exists of an aquatic component in the dietary protein and strongly implies that delta(15)N analysis should be undertaken routinely when dating human bones

Autistic spectrum disorder in prehistory

Individuals with 'extraordinary' or 'different' minds have been suggested to be central to invention and the spread of new ideas in prehistory, shaping modern human behaviour and conferring an evolutionary advantage at population level. In this article the potential for neuropsychiatric conditions such as autistic spectrum disorders to provide this difference is explored, and the ability of the archaeological record to provide evidence of human behaviour is discussed. Specific reference is made to recent advances in the genetics of these conditions, which suggest that neuro psychiatric disorders represent a non-advantageous, pathological extreme of the human mind and are likely a by-product rather than a cause of human cognitive evolution

Missing mammals from the Mesolithic middens: a comparison of the fossil and archaeological records from Scotland

Wild mammmals were an essential source of food and materials for Mesolithic people in Scotland. However, most Mesolithic sites in Scotland contain scant evidence of the mammals that were exploited locally. In contrast, the fossil and contemporary records indicate that there was a very high and changing diversity of mammal species available to Mesolithic hunter-gatherers as the climate warmed at the end of the last Ice Age: up to 23 species of terrestrial and freshwater mammals from the fossil record compared to a maximum of 16 species from Mesolithic sites, but only four of these were found at more than two sites. The reasons for this disparity between the fossil and the archaeological records are discussed. In Scotland most Mesolithic sites with faunal remains are coastal shell middens, which may not be sites where mammals were routinely hunted and their carcasses processed. The shell midden sites are also of Later Mesolithic date and hence cannot reflect the Early Holocene fauna, which included cold climate species that had survived from the Lateglacial. Many areas have acid soils in which bones are only rarely preserved, and this may explain the absence of faunal materials from the majority of coastal and inland sites. The fact that larger mammals may have been processed at the kill sites, and that some mammals were exploited for their skins, futher reduces the chances of their survival in the archaeological record. Finally, optimal foraging for prey in relation to prey density may have meant that some large mammal species (e.g. moose) were not worth hunting except opportunistically. It is likely that all of these factors have contributed to the impoverished mammal fauna of the Scottish Mesolithic

The Mesolithic-Neolithic transition in western Scotland and its European context

The transition is considered in terms of four related questions: (i) HOW did the shift from foraging to farming happen? (ii) WHY did it happen? (iii) WHEN did it happen? (iv) WHY did it happen WHEN it did? The adoption of farming coincided with a shift to a more continental-type climate with lower winter precipitation, which improved the prospects for cereal cultivation. It is sug- gested that this was a key factor in the transition from Mesolithic to Neolithic across north-west Eu- rope as a whole.Mezolitsko-neolitski prehod obravnavamo glede na štiri povezana vprašanja: (i) KAKO se je zgodil prehod iz lovstva-nabiralništva v kmetovanje? (ii) ZAKAJ se je zgodil? (iii) KDAJ se je zgodil? (iv) ZAKAJ se je zgodil, KO se je zgodil? Do prevzema kmetovanja je prišlo v času, ko so klimatske razmere postale bolj kontinentalne in zimske padavine manj obilne. To je izboljšalo pogoje za gojenje žit. Menimo, da je bil to ključni dejavnik za prehod iz mezolitika v neolitik v celotni severozahodni Evropi

Loschmidt echo and fidelity decay near an exceptional point

Non-Hermitian classical and open quantum systems near an exceptional point (EP) are known to undergo strong deviations in their dynamical behavior under small perturbations or slow cycling of parameters as compared to Hermitian systems. Such a strong sensitivity is at the heart of many interesting phenomena and applications, such as the asymmetric breakdown of the adiabatic theorem, enhanced sensing, non-Hermitian dynamical quantum phase transitions and photonic catastrophe. Like for Hermitian systems, the sensitivity to perturbations on the dynamical evolution can be captured by Loschmidt echo and fidelity after imperfect time reversal or quench dynamics. Here we disclose a rather counterintuitive phenomenon in certain non-Hermitian systems near an EP, namely the deceleration (rather than acceleration) of the fidelity decay and improved Loschmidt echo as compared to their Hermitian counterparts, despite large (non-perturbative) deformation of the energy spectrum introduced by the perturbations. This behavior is illustrated by considering the fidelity decay and Loschmidt echo for the single-particle hopping dynamics on a tight-binding lattice under an imaginary gauge field.Comment: 11 pages, 6 figures, to appear in Annalen der Physi

Insect herbivory on seedlings of rainforest trees: effects of density and distance of conspecific and heterospecific neighbours

Natural enemies of plants such as insect herbivores can contribute to structuring and maintaining plant diversity in tropical forests. Most research in this area has focused on the role of specialized enemies and the extent to which herbivory on individual plant species is density‐dependent. Relatively few insect herbivores specialize on a single host plant species. Insect herbivores that feed on more than one plant species may link the regeneration dynamics of their host species through “apparent competition” or “apparent mutualism.” We investigated herbivory and survival of seedlings of two tropical tree species (Cordia alliodora and Cordia bicolor) in the forests of Barro Colorado Island (Panama). We used experiments and observations to assess seedling fate in relation to the presence of conspecifics and heterospecifics across a range of spatial scales. Herbivory significantly increased seedling mortality and was highest at high local densities of C. alliodora seedlings. There was also evidence that high local densities of C. alliodora increased herbivory on co‐occurring C. bicolor seedlings. Synthesis. The elevated rates of seedling herbivory at high densities of conspecifics documented in our study are consistent with the predictions of the Janzen–Connell hypothesis, which explains how so many plant species can coexist in tropical forests. Our data also highlight the possibility that herbivore‐mediated density‐dependence, facilitated by herbivores that feed on multiple plant species, can also occur across plant species. Enemy‐mediated indirect effects of this sort have the potential to structure plant communities

Assessing the potential of phytolith analysis to investigate local environment and prehistoric plant resource use in temperate regions:A case study from Williamson’s Moss, Cumbria, Great Britain

Please note: this work is permanently embargoed in OpenBU. No public access is forecasted for this item. To request private access, please click on the locked Download file link and fill out the appropriate web form.First author draf

Predators reduce extinction risk in noisy metapopulations

Background Spatial structure across fragmented landscapes can enhance regional population persistence by promoting local “rescue effects.” In small, vulnerable populations, where chance or random events between individuals may have disproportionately large effects on species interactions, such local processes are particularly important. However, existing theory often only describes the dynamics of metapopulations at regional scales, neglecting the role of multispecies population dynamics within habitat patches. Findings By coupling analysis across spatial scales we quantified the interaction between local scale population regulation, regional dispersal and noise processes in the dynamics of experimental host-parasitoid metapopulations. We find that increasing community complexity increases negative correlation between local population dynamics. A potential mechanism underpinning this finding was explored using a simple population dynamic model. Conclusions Our results suggest a paradox: parasitism, whilst clearly damaging to hosts at the individual level, reduces extinction risk at the population level