The aim of this thesis is to investigate the environmental changes across the Mesolithic-Neolithic transition (c.7000-5000 cal BP) at two sites in north-west Europe. Specific research questions focus on the role of fire, the interaction of climate and environmental change and human impacts, and the degree of continuity across the transition. Previous work has led to hypotheses of human impacts in the late Mesolithic, usually through the use of fire, increasing the abundance of food. Detection of these practices and the change to farming in the Neolithic has long been the study of pollen analysts, but in this project additional techniques of NPPs, size-class differentiated charcoal, and silicon and titanium were added at high resolution in order to determine the relationships between the different forcing factors on mid-Holocene environments. Sites were selected close to locations where known later Mesolithic artefacts have been found, with dated archaeological excavations. An upland UK bog site (Dan Clough Moss, near March Hill, West Yorkshire) and a lowland Swedish lake (Bökeberg, Skåne) provided contrasting environments, and enabled a range of proxies to be used from terrestrial peat and limnic sediments. 14C dates from selected macrofossils enabled an age-depth curve to be produced from each profile, with a Bayesian model applied to estimate the age of each sample. Results show a detailed record of woodland change from both areas. At Dan Clough Moss, disturbance phases with evidence of local fires occur frequently (typically every 20-30 years) in the late Mesolithic, and have low magnitude but consistent records of coprophilous fungi. Some phases of disturbance are different however, without the fungal spore evidence, and with heath plants increasing in representation. Drier phases appear to correlate with more local fire, and increased hazel. The transition is marked by a change to longer duration but distant fires, and longer periods of woodland disturbance, increased ruderal species and more heathland. The dates of occupation phases show a late survival of Mesolithic practices, overlapping with the Neolithic by around 300 years. At Bökeberg, a contrasting pattern is shown, with longer-duration phases of inferred human impact being replaced by shorter episodes of fire-associated disturbance after the date of the transition. Pollen and spore zones of disturbance concur with the dated occupation of late Mesolithic sites at the former lake edge. There is some evidence for markedly wetter, and then significantly drier, climate through the transition, and it could be inferred that this influenced the change in food production economies. However, the overall landscape changed only subtly, with more evidence of potential weeds of cultivation. At Bökeberg, there was no overlap- both radiocarbon and palynology suggest an abrupt transition from Mesolithic to Neolithic. The landscape impact of the transition from Mesolithic to Neolithic at both sites was not a clear and consistent one. While Ulmus decline levels and thereafter had increases in weed species and other herbs the overall balance of trees and shrubs changed less than 20%. At both sites, climate may have been influential, although the evidence is inconclusive. Fires were important at both sites and in both periods, but at different scales and duration. Disturbance phases varied within the Mesolithic as well as between the Mesolithic and the Neolithic.

This essay will discuss where the people who built the passage graves and the first farmers at the Falbygden area in Sweden came from. That the first farmers built the passage graves is today a given fact, but how did the Neolithic transition take form in Scandinavia? Two theories have been put forward over the past century, that they learned through cultural diffusion, or that the first farmers were immigrants. Recent DNA- and Strontiumanalyses have been made on skeletons from passage graves from Falbygden and on skeletons from different regions across Europe, both from Mesolithic and Neolithic people. These results show that the Mesolithic hunter-gatherers shares no or little continuity with the Neolithic farmers, even in cases where the two groups lived in close neighbouring for a long time.

This bachelor thesis investigates nitrogen and carbon stable isotopes in Ireland during the Mesolithic and Neolithic. In recent years, the understanding of subsistence strategies in Northwestern Europe has improved and it has shown that the dietary stable isotope data of Neolithic Ireland is an extreme outlier in the region. The aim is to examine the manuring and canopy effect that have often been suggested to be possible contributing factors for this difference. There is no certainty whether this difference is due to diet, land use or any other cause while these effects remain uninvestigated. The effects are studied by comparing dietary isotopes with sources about land use, such as pollen and geochemical data, for four sites: Carrowkeel, Poulnabrone, Knowth and the Mound of Hostages (Duma na nGiall), which together comprise c. 80% of the Neolithic Irish stable isotope record. The manuring effect is not visible in the current stable isotope, pollen, geochemical, zoological and archaeobotanical record. The canopy effect may be reflected in that same dataset. If the canopy effect is indeed the cause of the difference between Irish and Southern British δ13C values, a detailed comparison between the pollen data close to the origin of the carbon stable isotope samples and the carbon stable isotope samples in another area, such as Southern Britain, may explain the outlier position of Ireland in North-western Europe. / Denna C-uppsats undersöker kväve-och kolisotoper i det neolitiska och mesolitiska Irland. Genom en stor tillväxt av data har det blivit tydligt att de irländska kväve- och kolvärdena är extrema jämfört med resten av britannien. Gödslingseffekten och trädskiktseffekten är två effekter som har misstänkts att orsaka denna skillnad. Syftet är att undersöka dessa effekter genom att leta efter samband mellan markbruk och stabila isotoper. Fyra begravningsplatser har valts ut till detta syfte: Knowth, Carrowkeel, Poulnabrone och Duma na nGiall (Mound of Hostages). 80% av alla stabila kol- och kväveisotopvärden härstammar från dessa begravningsplatser. Gödslingseffekten gick inte att identifiera i datasamlingen som innehåller stabila isotopvärden, pollen, zoologisk data, arkeobotanisk och geokemisk data. Trädskiktseffekten möjligtvis bekräftas av datasammanställningen. För att kunna förklara den fullständiga skillnaden mellan syd-brittiska och irländska δ13C-värden behövs en studie som även inkluderar detaljerad data av neolitiskt markbruk från Brittiska ön.

No / Stable isotope analysis has provided crucial new insights into dietary change at the Neolithic transition in north-west Europe, indicating an unexpectedly sudden and radical shift from marine to terrestrial resources in coastal and island locations. Investigations of early Neolithic skeletal material from Sumburgh on Shetland, at the far-flung margins of the Neolithic world, suggest that this general pattern may mask significant subtle detail. Analysis of juvenile dentine reveals the consumption of marine foods on an occasional basis. This suggests that marine foods may have been consumed as a crucial supplementary resource in times of famine, when the newly introduced cereal crops failed to cope with the demanding climate of Shetland. This isotopic evidence is consistent with the presence of marine food debris in contemporary middens. The occasional and contingent nature of marine food consumption underlines how, even on Shetland, the shift from marine to terrestrial diet was a key element in the Neolithic transition.

Ce mémoire reconstitue l’histoire des théories, modèles et hypothèses qui ont été formulés, principalement en archéologie, afin d’expliquer la naissance de l’agriculture qui correspond, du point de vue chronologique, à la transition (ou révolution) néolithique. Ces schèmes explicatifs sont décrits chronologiquement depuis la naissance de l’archéologie préhistorique, dans la première moitié du XIXe siècle, jusqu’à maintenant. Ils sont classifiés en fonction des principales écoles qui ont joué un rôle prédominant en archéologie préhistorique depuis son origine, soit : l’évolutionnisme multilinéaire, l’école culturelle-historique, le processualisme, le néodarwinisme et le postprocessualisme. Les théories spécifiques (dites de « niveau mitoyen » ou « régionales ») qui ont été avancées par ces écoles sont présentées dans leur ordre chronologique, soit (principalement) : les théories de la dessiccation ou de l’oasis, des flancs de colline, de la périphérie, du stress démographique, du festin compétitif, de la révolution des symboles, etc. Ce mémoire pose enfin les jalons d’une théorie multifactorielle qui intègre ou synthétise les principaux facteurs qui ont pu influer sur la naissance de l’agriculture et sur la transition néolithique. / This dissertation reconstructs the history of theories, models and hypotheses which have been proposed in order to explain the birth of agriculture, that is the neolithic transition or revolution. These explanatory schemes are described chronologically from the birth of prehistoric archaeology, in the first half of the 19th century, until today. They are classified according to the main schools which have played a leading role in prehistoric archaeology since its birth: multilinear evolutionism, the culture-historical school, processualism, neodarwinism and postprocessualism. The specific theories (also called “middle-range” or “regional”) which have been proposed by these schools are presented the chronological order: the theories of desiccation, oases, hilly flanks, periphery, population stress, competitive feasting, revolution of symbols, etc. Finally, this dissertation lays the ground for a multifactorial theory integrating or synthesizing the main factors which may have influenced the birth of agriculture and the neolithic transition.

Ce mémoire reconstitue l’histoire des théories, modèles et hypothèses qui ont été formulés, principalement en archéologie, afin d’expliquer la naissance de l’agriculture qui correspond, du point de vue chronologique, à la transition (ou révolution) néolithique. Ces schèmes explicatifs sont décrits chronologiquement depuis la naissance de l’archéologie préhistorique, dans la première moitié du XIXe siècle, jusqu’à maintenant. Ils sont classifiés en fonction des principales écoles qui ont joué un rôle prédominant en archéologie préhistorique depuis son origine, soit : l’évolutionnisme multilinéaire, l’école culturelle-historique, le processualisme, le néodarwinisme et le postprocessualisme. Les théories spécifiques (dites de « niveau mitoyen » ou « régionales ») qui ont été avancées par ces écoles sont présentées dans leur ordre chronologique, soit (principalement) : les théories de la dessiccation ou de l’oasis, des flancs de colline, de la périphérie, du stress démographique, du festin compétitif, de la révolution des symboles, etc. Ce mémoire pose enfin les jalons d’une théorie multifactorielle qui intègre ou synthétise les principaux facteurs qui ont pu influer sur la naissance de l’agriculture et sur la transition néolithique. / This dissertation reconstructs the history of theories, models and hypotheses which have been proposed in order to explain the birth of agriculture, that is the neolithic transition or revolution. These explanatory schemes are described chronologically from the birth of prehistoric archaeology, in the first half of the 19th century, until today. They are classified according to the main schools which have played a leading role in prehistoric archaeology since its birth: multilinear evolutionism, the culture-historical school, processualism, neodarwinism and postprocessualism. The specific theories (also called “middle-range” or “regional”) which have been proposed by these schools are presented the chronological order: the theories of desiccation, oases, hilly flanks, periphery, population stress, competitive feasting, revolution of symbols, etc. Finally, this dissertation lays the ground for a multifactorial theory integrating or synthesizing the main factors which may have influenced the birth of agriculture and the neolithic transition.

Neolithic dispersal in Europe has been alternatively explained through spread of farmers (migrationist position) or by adoption of farming by Mesolithic foragers (indigenist position). Mixed explanations have considered a combination of both processes. Neolithic dispersal in Central Europe was traditionally viewed as migrationist process. It was believed that farmers colonized the area and replaced indigenous foragers. During the last decade, authors have adhered to integrationist view as they have observed the continuity between Mesolithic and Neolithic technologies. Interestingly, the most recent genetic analyses again invoked the idea of colonization. Surprisingly, little attention has been paid to demographic modeling. The farming quickly spread in Central Europe between 5 600 and 5 400 calBC. Assuming colonization, Neolithic dispersal in Central Europe would have to be associated with high fertility rate of farmers. Our goal was to test whether the fertility rate of farmers was high enough to allow them to colonize Central Europe without admixture with local foragers. We produced four stochastic models of population dynamics of farmers during their colonization in Central Europe. The principle of Model 1-3 is based on methods of population projections. Model 4 stems from the wave of advance...

The complex demographic changes that underlie the expansion of anatomically modern humans out of Africa have important consequences on the dynamics of natural selection and our ability to detect it. In this thesis, I aimed to refine our knowledge on human population history using ancient genomes, and then used a climate-informed, spatially explicit framework to explore the interplay between complex demographies and selection. I first analysed a high-coverage genome from Upper Palaeolithic Romania from ~37.8 kya, and demonstrated an early diversification of multiple lineages shortly after the out-of-Africa expansion (Chapter 2). I then investigated Late Upper Palaeolithic (~13.3ky old) and Mesolithic (~9.7 ky old) samples from the Caucasus and a Late Upper Palaeolithic (~13.7ky old) sample from Western Europe, and found that these two groups belong to distinct lineages that also diverged shortly after the out of Africa, ~45-60 ky ago (Chapter 3). Finally, I used East Asian samples from ~7.7ky ago to show that there has been a greater degree of genetic continuity in this region compared to Europe (Chapter 4). In the second part of my thesis, I used a climate-informed, spatially explicit demographic model that captures the out-of-Africa expansion to explore natural selection. I first investigated whether the model can represent the confounding effect of demography on selection statistics, when applied to neutral part of the genome (Chapter 5). Whilst the overlap between different selection statistics was somewhat underestimated by the model, the relationship between signals from different populations is generally well-captured. I then modelled natural selection in the same framework and investigated the spatial distribution of two genetic variants associated with a protective effect against malaria, sickle-cell anaemia and β⁰ thalassemia (Chapter 6). I found that although this model can reproduce the disjoint ranges of different variants typical of the former, it is incompatible with overlapping distributions characteristic of the latter. Furthermore, our model is compatible with the inferred single origin of sickle-cell disease in most regions, but it can not reproduce the presence of this disorder in India without long-distance migrations.