Congratulations to Dr. Franziska Kobe, BAP PhD student at Freie Universitaet Berlin for successfully defending her PhD dissertation on April 28th!

Franziska says she was so happy to finish this important step in her life and it was unique to have her defense on her birthday, no less!

Commission:   Prof. Dr. Pavel E. Tarasov (reviewer)
Prof. Dr. Mayke Wagner (reviewer)
Prof. Dr. Frank Riedel (commission leader)
Prof. Dr. Serge A. Shapiro (deputy commission leader)
Dr. Philipp Hoelzmann (protocol)

Title: “A 32,000-year pollen record of vegetation, climate dynamics and glacial-interglacial environments of hunter-gatherer populations from Lake Ochaul, Cis-Baikal region of Siberia”

Abstract: The Lake Baikal region (LBR) has been the target of various archaeological and palaeoenvironmental research in the past. Multi-disciplinary and multi-national teams of researchers examine the LBR since 1997 contributing to the Baikal Archaeology Project (BAP). The main goals of the BAP are to investigate hunter-gatherer lifeways in Northern Asia using an individual life histories approach; to develop a robust chronology through intensive radiocarbon dating and Bayesian modelling of the archaeological remains; and to combine archaeological data with the results of high-resolution and accurately dated palaeoenvironmental records. Whereas resolution and number of studies increased over time, there are still large areas that are understudied, not least due to the huge dimension of the LBR. In particular, reconstruction of the last glacial/interglacial vegetation and climate history of the vast Cis-Baikal region outside the Lake Baikal coastal plains are not possible without detailed palaeoenvironmental records with AMS-based age control. Previous palynological studies around Lake Baikal point to the spatial-temporal variability in vegetation development across the LBR due to its large area with complex topography and influence of various elements of the global climate system. Archaeological research also demonstrates some spatial differences in the lifestyle and subsistence strategies of the Neolithic and Bronze Age hunter-gatherers within the LBR. Thus, detailed reconstruction of microregional environments is crucial for better understanding of the evolution of hunter-gatherer cultures. Lakes with continuous sedimentation may serve as natural archives, which preserve multi-proxy records of past environments and have a great potential for the correlation of archaeological and palaeoenvironmental records within geoarchaeological microregions.

This doctoral thesis contributes to the BAP by filling gaps in current knowledge and providing a detailed palaeoenvironmental record of the past 32,000 years obtained from a 7.24-m-long sediment core from Lake Ochaul (54°14’N, 106°28’E; 641 m a.s.l.), a small freshwater lake situated in the Upper Lena microregion of Cis-Baikal, rich in archaeological sites dated from the Upper Palaeolithic to the Bronze and Iron Age. The main results are presented in three peer-reviewed studies, published in international scientific journals. The focus was on two archaeologically and environmentally important time intervals: the (1) Last Glacial Maximum (LGM: ca. 28,000–20,000 years ago) and (2) the Lateglacial and Holocene (ca. 13,500 years ago to today). The respective AMS-dated parts of the Lake Ochaul core were palynologically analysed, and the obtained results were discussed and compared with other records from and outside the LBR to examine spatial-temporal differences of reconstructed environment and climate changes and their driving forces.

The published archaeological data from Cis-Baikal indicates that the region witnessed continuous hunter-gatherer population during the LGM, the climatically harshest part of the Late Quaternary, and therefore may have played an important role in the spread of anatomically modern humans to Northeast Asia and North America. The extent of deforestation during that time is still under discussion. The new pollen and biome reconstruction records from Lake Ochaul show that productive steppe or/and herbaceous tundra dominated this area during the LGM. This type of vegetation and thin snow cover were highly beneficial for large herbivores of the so-called “mammoth fauna” which on the other hand provided regional hunter-gatherer groups with a sufficient amount of food and raw materials for clothes and hunting tools. On the other hand, the LGM pollen record of Lake Ochaul shows continuous presence of boreal trees and shrubs such as birch, spruce, several pine taxa, larch and willow, in proportions that can hardly be explained by far-distant pollen transport. The survival of boreal trees during the LGM and the following spread of taiga forests across Siberia remains one of the long-debated topics in palaeoenvironmental research. This thesis provides well-argued evidence that the relatively moist area around Lake Ochaul was among the glacial refugia, where boreal trees and shrubs persisted the coldest and driest LGM climate interval and from where they quickly spread over the entire LBR during the Lateglacial.

During the Allerød, open taiga forest vegetation was already present around Lake Ochaul. The following Younger Dryas stadial led to a more open forest-tundra landscape with high participation of shrubby and patchy forest associations. The onset of the Holocene (ca. 11,650 cal yr BP) is marked by a further rapid spread of boreal forest vegetation around Lake Ochaul, which occurred about 1000 years earlier than at Lake Kotokel in Trans-Baikal. The Early Holocene warming was interrupted by several rapid oscillations towards colder climate showing the interplay of global insolation, sea level and ice sheet transformations on the regional climate and environments. Temperature and moisture conditions became most favourable during the Middle Holocene (ca. 8000–4200 cal yr BP). During the so-called “Holocene climate optimum”, percentages for boreal tree taxa reached highest values, speaking for densely forested landscapes around Lake Ochaul and a maximal spread of forest vegetation in the LBR. The reconstructed changes in the vegetation cover during the Early and Middle Holocene were associated with a major climate amelioration following a transformation of the atmospheric circulation and a stronger year-round impact of the North Atlantic air masses on the regional climate leading to thicker and longer-lasting snow cover. Those vegetational and climatic transformations along with the extinction of the greater part of the mammoth fauna, one of the main food resources for hunter-gatherer communities, might be a reason for the reported changes in the health conditions and lifeway of the Early Neolithic Kitoi populations, leading to a cultural “hiatus” (ca. 6660–6060 cal yr BP) suggested by the archaeological records from the LBR. The Late Holocene pollen record indicates gradual opening of the forested landscape around Lake Ochaul, which could be related to the gradual decrease in the Northern Hemisphere summer insolation and air temperatures, but also with an intensified human impact in the LBR.

Six AMS radiocarbon dates on large herbivorous animals’ bone material from the Ochaul archaeological site located on the northern lake shore indicate that hunting activities around the lake took place during a very long period, with the earliest evidence of the extinct Palaeolithic horse dated to ca. 27,780–27,160 cal yr BP (95% probability range). Other dates indicate deer and elk hunting during the Mesolithic (ca. 8850–8450 cal yr BP), Early, Middle and Late Neolithic (between ca. 6840 and 5490 cal yr BP) and the Iron Age (ca. 2120–1930 cal yr BP). These results demonstrate that despite major environmental transformations during the LGM and Holocene periods, Lake Ochaul and surrounding area remained attractive for large herbivores and for prehistoric hunter-gatherers, who seem to have been present there even during the Middle Neolithic cultural “hiatus”, as documented by the AMS-dated zooarchaeological record from the cultural layers of the Ochaul site.

Read about Franziska and her research here: https://baikalproject.artsrn.ualberta.ca/team/franziska-kobe/?portfolioCats=5%2C6%2C7%2C8%2C9

Way to go, Dr. Kobe! We wish you all the best in your future endeavors!