TY - JOUR A1 - Klemm, Juliane A1 - Herzschuh, Ulrike A1 - Pestryakova, Luidmila Agafyevna T1 - Vegetation, climate and lake changes over the last 7000 years at the boreal treeline in north-central Siberia JF - Quaternary science reviews : the international multidisciplinary research and review journal KW - Tundra-taiga ecotone KW - Larix gmelinii KW - Palynology KW - Sediment geochemistry KW - Mean July temperature KW - Ordination KW - WA-PLS KW - Procrustes rotation Y1 - 2016 U6 - https://doi.org/10.1016/j.quascirev.2015.08.015 SN - 0277-3791 VL - 147 SP - 422 EP - 434 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Herzschuh, Ulrike A1 - Pestryakova, Luidmila Agafyevna A1 - Klemm, Juliane A1 - Epp, Laura Saskia A1 - Tiedemann, Ralph T1 - Genetic data from algae sedimentary DNA reflect the influence of environment over geography JF - Scientific reports N2 - Genetic investigations on eukaryotic plankton confirmed the existence of modern biogeographic patterns, but analyses of palaeoecological data exploring the temporal variability of these patterns have rarely been presented. Ancient sedimentary DNA proved suitable for investigations of past assemblage turnover in the course of environmental change, but genetic relatedness of the identified lineages has not yet been undertaken. Here, we investigate the relatedness of diatom lineages in Siberian lakes along environmental gradients (i.e. across treeline transects), over geographic distance and through time (i.e. the last 7000 years) using modern and ancient sedimentary DNA. Our results indicate that closely-related Staurosira lineages occur in similar environments and less-related lineages in dissimilar environments, in our case different vegetation and co-varying climatic and limnic variables across treeline transects. Thus our study reveals that environmental conditions rather than geographic distance is reflected by diatom-relatedness patterns in space and time. We tentatively speculate that the detected relatedness pattern in Staurosira across the treeline could be a result of adaptation to diverse environmental conditions across the arctic boreal treeline, however, a geographically-driven divergence and subsequent repopulation of ecologically different habitats might also be a potential explanation for the observed pattern. Y1 - 2015 U6 - https://doi.org/10.1038/srep12924 SN - 2045-2322 VL - 5 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Niemeyer, Bastian A1 - Klemm, Juliane A1 - Pestryakova, Luidmila Agafyevna A1 - Herzschuh, Ulrike T1 - Relative pollen productivity estimates for common taxa of the northern Siberian Arctic JF - Review of palaeobotany and palynology : an international journal N2 - Pollen productivity estimates (PPE) are used to quantitatively reconstruct variations in vegetation within a specific distance of the sampled pollen archive. Here, for the first time, PPEs from Siberia are presented. The study area (Khatanga region, Krasnoyarsk territory, Russia) is located in the Siberian Sub-arctic where Larix is the sole forest-line forming tree taxon. Pollen spectra from two different sedimentary environments, namely terrestrial mosses (n = 16) and lakes (n = 15, median radius similar to 100 m) and their surrounding vegetation were investigated to extract PPEs. Our results indicate some differences in pollen spectra between moss and lake pollen. Larix and Cyperaceae for example obtained higher representation in the lacustrine than in terrestrial moss samples. This highlights that in calibration studies, modem and fossil datasets should use archives of similar sedimentary origin. Results of an Extended R-Value model were applied to assess the relevant source area of pollen (RSAP) and to calculate the PPEs for both datasets. As expected, the RSAP of the moss samples was very small (about 10 m) compared to the lacustrine samples (about 25 km). Calculation of PPEs for the six most common taxa yielded generally similar results for both datasets. Relative to Poaceae (reference taxon, PPE = 1) Betula nana-type (PPEmoss: 1.8, PPElake: 1.8) and Alnus fruticosa-type (PPEmoss:6.4, PPElake:2.9) were overrepresented while Cyperaceae (PPEmoss:0.5, PPElake:0.1), Ericaceae (PPEmoss: 0.3, PPElake <0.01), Salix (PPEmoss:0.03, PPElake <00.1) and Larix (PPEmoss: <0.01, PPElake:0.2) were under-represented in the pollen spectra compared to the vegetation in the RSAP. The estimation for the dominant tree in the region, Larix gmelinii, is the first published result for this species, but needs to be considered very preliminary. The inferred sequence from over- to under-representation is mostly consistent with results from Europe; however, the absolute values show some differences. Gathering vegetation data was limited by the remoteness of our study area and a lack of high-resolute satellite imagery and vegetation maps. Our estimate may serve as a first reference to strengthen future vegetation reconstructions in this climate-sensitive region. (C) 2015 Elsevier B.V. All rights reserved. KW - Lacustrine surface samples KW - Moss samples KW - Extended R-Value model KW - Pollen source area KW - Khatanga river Y1 - 2015 U6 - https://doi.org/10.1016/j.revpalbo.2015.06.008 SN - 0034-6667 SN - 1879-0615 VL - 221 SP - 71 EP - 82 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Klemm, Juliane A1 - Herzschuh, Ulrike A1 - Pisaric, Michael F. J. A1 - Telford, Richard J. A1 - Heim, Birgit A1 - Pestryakova, Luidmila Agafyevna T1 - A pollen-climate transfer function from the tundra and taiga vegetation in Arctic Siberia and its applicability to a Holocene record JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - This study aims to establish, evaluate, and apply a modern pollen-climate transfer function from the transition zone between arctic tundra and light-needled taiga in Arctic Siberia. Lacustrine samples (n = 96) from the northern Siberian lowlands of Yakutia were collected along four north-to-south transects crossing the arctic forest line. Samples span a broad temperature and precipitation gradient (mean July temperature, T-July: 7.5-18.7 degrees C; mean annual precipitation, P-ann: 114-315 mm/yr). Redundancy analyses are used to examine the relationship between the modern pollen signal and corresponding vegetation types and climate. Performance of transfer functions for T-July and P-ann were cross-validated and tested for spatial autocorrelation effects. The root mean square errors of prediction are 1.67 degrees C for T-July and 40 mm/yr for P-ann. A climate reconstruction based on fossil pollen spectra from a Siberian Arctic lake sediment core spanning the Holocene yielded cold conditions for the Late Glacial (1-2 degrees C below present T-July). Warm and moist conditions were reconstructed for the early to mid Holocene (2 degrees C higher T-July than present), and climate conditions similar to modern ones were reconstructed for the last 4000 years. In conclusion, our modern pollen data set fills the gap of existing regional calibration sets with regard to the underrepresented Siberian tundra-taiga transition zone. The Holocene climate reconstruction indicates that the temperature deviation from modern values was only moderate despite the assumed Arctic sensitivity to present climate change. KW - Mean July temperature KW - Reconstruction KW - Weighted-average partial least squares KW - Autocorrelation KW - Yakutia Y1 - 2013 U6 - https://doi.org/10.1016/j.palaeo.2013.06.033 SN - 0031-0182 SN - 1872-616X VL - 386 SP - 702 EP - 713 PB - Elsevier CY - Amsterdam ER -