We compare a Bayesian modelling-based technique with weighted averaging (WA) and weighted averaging-partial least squares (WA-PLS) regression in pollen-based summer temperature transfer function calibration. We test the methods using a new, 113-sample calibration set from Estonia, Lithuania and European Russia, and a Holocene fossil pollen sequence from Lake Kharinei, a previously studied lake in northeast European Russia. We find WA-PLS to outperform WA, probably because of smaller edge-effect biases in the ends of the calibration set gradient. The Bayesian-based calibration models show further improved performance compared with WA-PLS in leave-one-out cross-validation, while additional h-block cross-validation shows the Bayesian method to be little affected by spatial autocorrelation. Comparison with independent climate proxies reveals, however, some clear biases in the Bayesian palaeotemperature reconstructions, likely reflecting in part some specific limitations of our calibration set. As the selected prior parameters can significantly affect both Bayesian cross-validation performance and reconstructions, there is a clear need to further test the Bayesian method in different geographic contexts and over different timescales, with special attention given to the selection of the most realistic priors in each situation. In general, our finding that statistically well-performing transfer functions may produce clearly differing palaeotemperature reconstructions urges caution in transfer functionbased inferences. We additionally test a spatially restricted, 58-sample subset of the full 113-sample calibration set. We find some reduced biases with the smaller set, likely because of complex, partially bimodal responses of several taxa along the longer temperature gradient, ill-suited for calibration methods assuming unimodal responses to climate.

ABSTRACT. Archaeological, geological, and paleoecological investigations supported by radiocarbon dating enabled us to present a reconstruction of chronologically based paleoenvironmental and human activity changes in the Sventoji region, NW Lithuania, during the period 4000-800 cal BC. In addition, we describe the main stages of the Late Glacial and Holocene periods in the area. The Baltic Ice Lake regression was succeeded by a terrestrial period until the Littorina Sea maximal transgression at 5700-5400 cal BC. A marine bay with brackish water was transformed into a freshwater lagoon before the oldest archaeological evidence of human presence, i.e. 4000/3700 cal BC. However, the presence of Cerealia type and Plantago lanceolata pollen dating back to about 4400-4300 cal BC suggests earlier farming activities in the area. Pollen analyses show the minor but continuous role of cereal cultivation after 3250 cal BC. Due to the predominance of the boggy landscape in the immediate vicinity of the Sventoji sites, agricultural fields were situated further away from the sites themselves. Exploitation of remote areas of the freshwater basin by diverse fishing gear was proven by the discovery of a new fishing site, Sventoji 41 (2900-2600 cal BC). This finding together with data of previous research suggest a complex and elaborate coastal economy involving seal hunting and year-round freshwater fishing during the 3rd millennium cal BC. A decline in human activity is seen in the pollen diagram after 1800 cal BC, which could be due to significant environmental changes, including overgrowth of the freshwater lagoon basin with vegetation.

Gryguc, G., Kisielienė, D., Stančikaitė, M., Šeirienė, V., Skuratovič, Ž., Vaitkevičius, V., Gaidamavičius, A., 2013 Abstract This paper presents new data describing the Holocene environmental history of the Briaunis pal aeolake, Eastern Lithuania. Shortly before 9600 cal yr BP, sedimentation began in an oligotrophic deepwater basin, whereas the Early Holocene instability of the environmental regime caused the influx of detrital sediment into the basin. A birch forest dominated in the surrounding landscapes, and at ca. 9600 cal yr BP, the spread of Ulmus, Alnus, Populus and Corylus began, suggesting a shortlived climatic amelioration. A subsequent drop of the water table and increasing influx of the terrigenous material continued from 9600 to 9300-9200 cal yr BP. The ensuing climatic stability caused the formation of a deciduous forest and the regional spread of Picea. Some instability, i.e. a decline in the thermophilous species, as well as the appearance of boreal and northern alpine diatoms, could be associated with the socalled "8.2 ka event". This reversal was followed by ameliora tion and prospering of the water plants typical of the Holocene climatic optimum from 7900 to 7200-7100 cal yr BP. At aproximatelly 6600-6500 cal yr BP, a small rise of the water table was documented and bogforming processes dominated until ca. 3600-3400 cal yr BP, when a smallscale deepening of the basin occured.

This paper presents new bio-, litho-and chronostratigraphical evidence from two adjacent sediment sequences of the Tõdva and Saku basins, northern Estonia that refine the age estimate of the Palivere ice-marginal zone and the deglaciation history of Estonia. Previous palynological studies demonstrated the presence of late-glacial sediments in the area; however, those sections were not dated, and their ages were poorly constrained. New accelerator mass spectrometry (AMS) 14 C dates show that sedimentation in the Tõdva basin started at approximately 13 200 cal yr BP. Therefore, because the studied sites are located at the distal part of this zone, we infer that this age represents the minimum timing of the ice retreat from the Palivere ice-marginal zone.