CIRCULATION REGIME AND REDOX-CONDITIONS IN SALINE LAKE SHIRA (KHAKASIA, SIBERIA): FROM MODERN OBSERVATIONS TO PALEO-RECONSTRUCTION

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ENVIRONMENTS OF SOUTHWESTERN SIBERIA AND NORTHWESTERN MONGOLIA IN THE LATE HOLOCENE (BASED ON THE LAKE SEDIMENTS STUDY)

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The Javakheti Plateau: Megaliths, Villages, and Obsidian mines in the Prehistory of the Lesser Caucasus of Georgia

The surveys carried out during the last decade in the Javakheti Plateau (Lesser Caucasus, Georgia) led to the discovery of hundreds of archaeological sites among which are obsidian mining-fields, different types of megaliths and kurgans, complex villages, and basalt/andesite quarries, which were exploited mainly during the Bronze Age. All sites are located between c. 1500 and 2500 m of altitude, where present temperatures are well below 0° Celsius during the winter months. This chapter discusses the complexity of the archaeological landscapes we have investigated, their probable seasonal exploitation, and suggested complementarities between residential, funerary, and mining areas, whose archaeological remains in no case overlap. The systematic occurrence of megalithic structures and scatters of obsidian artefacts, sometimes located dozens of km from the extractive sources, poses many questions regarding their distribution and presence rarely asked by archaeologists

Linking modern pollen accumulation rates to biomass: Quantitative vegetation reconstruction in the western Klamath Mountains, NW California, USA

Quantitative reconstructions of vegetation abundance from sediment-derived pollen systems provide unique insights into past ecological conditions. Recently, the use of pollen accumulation rates (PAR, grains cm−2 year−1) has shown promise as a bioproxy for plant abundance. However, successfully reconstructing region-specific vegetation dynamics using PAR requires that accurate assessments of pollen deposition processes be quantitatively linked to spatially-explicit measures of plant abundance. Our study addressed these methodological challenges. Modern PAR and vegetation data were obtained from seven lakes in the western Klamath Mountains, California. To determine how to best calibrate our PAR-biomass model, we first calculated the spatial area of vegetation where vegetation composition and patterning is recorded by changes in the pollen signal using two metrics. These metrics were an assemblage-level relevant source area of pollen (aRSAP) derived from extended R-value analysis (sensu Sugita, 1993) and a taxon-specific relevant source area of pollen (tRSAP) derived from PAR regression (sensu Jackson, 1990). To the best of our knowledge, aRSAP and tRSAP have not been directly compared. We found that the tRSAP estimated a smaller area for some taxa (e.g. a circular area with a 225 m radius for Pinus) than the aRSAP (a circular area with a 625 m radius). We fit linear models to relate PAR values from modern lake sediments with empirical, distance-weighted estimates of aboveground live biomass (AGLdw) for both the aRSAP and tRSAP distances. In both cases, we found that the PARs of major tree taxa – Pseudotsuga, Pinus, Notholithocarpus, and TCT (Taxodiaceae, Cupressaceae, and Taxaceae families) – were statistically significant and reasonably precise estimators of contemporary AGLdw. However, predictions weighted by the distance defined by aRSAP tended to be more precise. The relative root-mean squared error for the aRSAP biomass estimates was 9% compared to 12% for tRSAP. Our results demonstrate that calibrated PAR-biomass relationships provide a robust method to infer changes in past plant biomass

Cyprus as an ancient hub for house mice and humans

© 2018 The Authors. Journal of Biogeography Published by John Wiley & Sons Ltd Aim: The distribution of the western house mouse (Mus musculus domesticus) around the world has been strongly influenced by the movement of humans. The close association between the house mouse and human phylogeography has been primarily studied in the peripheral distribution of the species. Here, we inferred the complex colonization history of Cyprus, situated close to the centre of the house mouse distribution and one of the first European islands to be colonized by the species. We investigated the resulting complexity of house mouse population genetics as well as considering the value of the house mouse as a bioproxy for studying modern human movement. Location: The study was carried out on Cyprus. Methods: The analysis was performed using 221 new mitochondrial D-loop sequences and assessed the fine-scale population genetic structure using 18 autosomal microsatellite loci from 191 modern house mice specimens. Results: We found a high genetic variability in the island that is illustrated by the presence of individuals from 9 of the 11 previously identified house mouse haplogroups for the D-loop, reflecting the hub-like nature of the island to mice. Two main waves of mouse introductions were tentatively identified based on coalescent and mismatch analysis. The first is apparently related to the Bronze Age expansion and the second one to more recent human movements. Cyprus represents an island with high complexity due to different introductions related to human transport and activity. Main conclusions: The dispersal of mice along with humans has left a complex footprint on the island with two main waves of introductions suggested. The phylogeography of the house mouse on Cyprus is in concordance with the complex human colonization history of the island and validates the use of the house mouse as a proxy to study human migration

Cambios paleoambientales desde el Pleistoceno tardío hasta el Holoceno medio basados en el registro de diatomeas en la Salina del Bebedero (San Luis, Argentina)

This study analyzes the environmental changes that occurred in the western sector of the San Luis province (Argentina) during the Late Pleistocene to Middle Holocene period (approximately 12,600 to 3,600 years BP). The information provided by diatoms as paleobiological indicators is used for this analysis. We examined the lower 5 meters of the 10-meter-long SBIII core, which was recovered from the endorheic and hypersaline shallow lake known as Salina del Bebedero (33°20’S-66°45’W, 380 m a.s.l.). The observed peaks of relative abundance of the planktonic diatom Cyclotella choctawhatcheeana suggest episodes of substantial water supply to the shallow lake from the Andes mountains via the Desaguadero river. These episodes were interspersed with periods of low water levels, resulting in very shallow to marsh environments characterized by the presence of epiphytic and benthic diatoms. Furthermore, we discuss and integrate the inferred paleoenvironmental information obtained from the diatom records, along with data from other proxies such as pollen and sedimentology. This integration aims to enhance the previously developed paleoenvironmental model for the region, covering the period between approximately 12,600 and 3,600 years BP. Overall, this research significantly contributes to the understanding of diatom assemblages in hypersaline lacustrine systems of the eastern Andes throughout the studied period, revealing the importance of certain taxa as indicators of wetter conditions during the early Holocene and in more recent stages within this timeframe. Additionally, this study aims to expand our existing knowledge of diatoms biodiversity in this province.Este trabajo aporta herramientas de análisis para la comprensión de los cambios ambientales ocurridos en el sector occidental de la provincia de San Luis (Argentina) entre el periodo del Pleistoceno tardío y el Holoceno medio (ca. 12.600 a ca. 3.600 años AP), utilizando la información provista por diatomeas, como indicadores paleobiológicos. Se analizó la mitad inferior del testigo SBIII (10 a 5 m) obtenido en la cuenca endorreica salino-lacustre Salina del Bebedero (33° 20′ S; 66° 45′ O; 380 (m s.n.m.). Los picos de mayor abundancia relativa de la especie planctónica Cyclotella choctawhatcheeana sugieren episodios de gran aporte de agua a la laguna, procedente de la Cordillera de los Andes a través del río Desaguadero. Estos episodios estuvieron intercalados por periodos con bajos niveles lacustres (ambientes someros o palustres) caracterizados por la presencia de diatomeas epifíticas y bentónicas y se identificaron intervalos donde no se encontraron diatomeas. También discutimos y articulamos la información paleoambiental inferida para el período comprendido entre ca. 12.600 y 3.600 años AP, a partir de los registros de diatomeas, con la información disponible de otros proxies (polen y sedimentología), con el fin de mejorar el modelo paleoambiental generado previamente para la región. Este trabajo amplía el conocimiento de ensambles de diatomeas en sistemas lacustres hipersalinos de los Andes orientales durante el periodo estudiado, revelando la importancia de algunos taxones como indicadores de condiciones más húmedas durante el inicio del Holoceno y en etapas más recientes dentro de este periodo y, además, este estudio, profundiza los conocimientos existentes sobre la biodiversidad diatomológica en esta provincia

Genetic diversity and historical demography of underutilised goat breeds in North-Western Europe

In the last decade, several studies aimed at dissecting the genetic architecture of local small ruminant breeds to discover which variations are involved in the process of adaptation to environmental conditions, a topic that has acquired priority due to climate change. Considering that traditional breeds are a reservoir of such important genetic variation, improving the current knowledge about their genetic diversity and origin is the first step forward in designing sound conservation guidelines. The genetic composition of North-Western European archetypical goat breeds is still poorly exploited. In this study we aimed to fill this gap investigating goat breeds across Ireland and Scandinavia, including also some other potential continental sources of introgression. The PCA and Admixture analyses suggest a well-defined cluster that includes Norwegian and Swedish breeds, while the crossbred Danish landrace is far apart, and there appears to be a close relationship between the Irish and Saanen goats. In addition, both graph representation of historical relationships among populations and f4-ratio statistics suggest a certain degree of gene flow between the Norse and Atlantic landraces. Furthermore, we identify signs of ancient admixture events of Scandinavian origin in the Irish and in the Icelandic goats. The time when these migrations, and consequently the introgression, of Scandinavian-like alleles occurred, can be traced back to the Viking colonisation of these two isles during the Viking Age (793-1066 CE). The demographic analysis indicates a complicated history of these traditional breeds with signatures of bottleneck, inbreeding and crossbreeding with the improved breeds. Despite these recent demographic changes and the historical genetic background shaped by centuries of human-mediated gene flow, most of them maintained their genetic identity, becoming an irreplaceable genetic resource as well as a cultural heritage

Comparative phylogeography as an integrative approach to understand human and other mammal distributions in Europe.

Phylogeography refers to the phylogenetic analysis of organisms in the context of their geographical distribution. The analytical methods build phylogenetic trees and networks from haplotypes in order to investigate the history of the organisms. Phylogeographic studies have revealed the importance of climatic oscillations and the role of the Last Glacial Maximum (27,500 to 16,000 years ago) with the formation of refugia where distinct haplotypes originate in Europe. The population expansions and contractions into these refugial areas have driven the evolution of different lineages but the similarities and differences between species are still poorly understood. This thesis aims to gain a better understanding of the phylogeographical processes of different mammals’ species in Europe. This was done by collecting published mitochondrial DNA control region sequences of 29 different species and analysing them individually and comparatively. This research presents a standardised way of understanding phylogeography from the mitochondrial DNA perspective to improve the comparison of studies in the field. The project investigates the patterns of genetic diversity by examining various diversity indices to test for trends and commonalities. To enhance knowledge in phylogeography and the importance of refugia during the Last Glacial Maximum in Europe through a comparative phylogeographic meta-analysis of mammal species. This thesis developed novel insights into the phylogeographic interactions of different mammal species, including modern humans, in the European geographical context. Modern human phylogeography pattern from the short control region has been contextualised in the patterns observed for other mammal species, showing a homogeneous distribution across the continent. Finally, the commensal species Mus musculus domesticus (western house mouse) was investigated in detail from a current and a past phylogeographic perspective in two islands, Cyprus and Britain, using ancient and modern DNA. This was done using this new knowledge as a bioproxy to understand more recent human movements associated with the transport of this species. This thesis, therefore, provides an integrated study with a new comparative framework and with results on the phylogeographical patterns of humans and other mammals in Europe

La arqueología desde el microscopio. Aportes interdisciplinarios de las diatomeas a las problemáticas arqueológicas

Actualmente, las problemáticas arqueológicas generaran datos no solo desde la propia de la disciplina sino también desde teorías y metodologías provenientes de otras disciplinas. La Diatomología, una disciplina que forma parte de las Ciencias Biológicas, ha demostrado ser una importante herramienta para la Arqueología. El análisis de diatomeas ha sido aplicado en reconstrucciones paleoambientales, en el análisis de procesos de formación de sitio, en material arqueológico como el estudio de procedencia de materia prima para la cerámica, en el estudio del manejo prehistórico del agua y suelos, en los restos bioarquelógicos y, por último,  en la conservación del patrimonio tangible. El objetivo del presente trabajo es realizar una revisión crítica de la evolución y estado actual de los análisis diatomológicos en cuestiones arqueológicas, principalmente incluyendo los estudios latinoamericanos. Para ello se propone discutir las potencialidades y limitaciones de estos estudios, con el fin de generar un puente conceptual que sea de utilidad para investigadores interesados en trabajar con estas líneas

House Mice in the Atlantic Region: Genetic Signals of Their Human Transport

Background/Objectives: The colonization history of house mice reflects the maritime history of humans that passively transported them worldwide. We investigated western house mouse colonization in the Atlantic region through studies of mitochondrial D-loop DNA sequences from modern specimens. Methods: We assembled a dataset of 758 haplotypes derived from 2765 mice from 47 countries/oceanic archipelagos (a combination of new and published data). Our maximum likelihood phylogeny recovered five previously identified clades, and we used the haplotype affinities within the phylogeny to infer house mouse colonization history, employing statistical tests and indices. From human history, we predefined four European source areas for mice in the Atlantic region (Northern Europe excluding Scandinavia, Southern Europe, Scandinavia, and Macaronesia) and we investigated the colonization from these source areas to different geographic areas in the Atlantic region. Results: Our inferences suggest mouse colonization of Scandinavia itself from Northern Europe, and Macaronesia from both Southern Europe and Scandinavia/Germany (the latter likely representing the transport of mice by Vikings). Mice on North Atlantic islands apparently derive primarily from Scandinavia, while for South Atlantic islands, North America, and Sub-Saharan Africa, the clearest source is Northern Europe, although mice on South Atlantic islands also had genetic inputs from Macaronesia and Southern Europe (for Tristan da Cunha). Macaronesia was a stopover for Atlantic voyages, creating an opportunity for mouse infestation. Mice in Latin America also apparently had multiple colonization sources, with a strong Southern European signal but also input from Northern Europe and/or Macaronesia. Conclusions: D-loop sequences help discern the broad-scale colonization history of house mice and new perspectives on human history