@article{AndreevRaschkeBiskabornetal.2021,
  author    = {Andreev, Andrei and Raschke, Elena and Biskaborn, Boris and Vyse, Stuart Andrew and Courtin, J{\´e}r{\´e}my and B{\"o}hmer, Thomas and Stoof-Leichsenring, Kathleen R. and Kruse, Stefan and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike},
  title     = {Late Pleistocene to Holocene vegetation and climate changes in northwestern Chukotka (Far East Russia) deduced from lakes Ilirney and Rauchuagytgyn pollen records},
  series = {Boreas : an international journal of quaternary research},
  volume    = {50},
  journal   = {Boreas : an international journal of quaternary research},
  number    = {3},
  publisher = {Wiley-Blackwell},
  address   = {Oxford [u.a.]},
  issn      = {0300-9483},
  doi       = {10.1111/bor.12521},
  pages     = {652 -- 670},
  year      = {2021},
  abstract  = {This paper presents two new pollen records and quantitative climate reconstructions from northern Chukotka documenting environmental changes over the last 27.9 ka. Open tundra- and steppe-like habitats dominated between 27.9 and 18.7 cal. ka BP. Betula and Alnus shrubs might have grown in sheltered microhabitats but disappeared after 18.7 cal. ka BP. Although the climate was rather harsh, local herb-dominated communities supported herbivores as is evident by the presence of coprophilous spores in the sediments. The increase in Salix and Cyperaceae similar to 16.1 cal. ka BP suggests climate amelioration. Shrub Betula appeared similar to 15.9 cal. ka BP, and became dominant after similar to 15.52 cal. ka BP, whilst typical steppe communities drastically reduced. Very high presence of Botryococcus in the Lateglacial sediments reflects widespread shallow habitats, probably due to lake level increase. Shrub Alnus became common after similar to 13 cal. ka BP reflecting further climate amelioration. Simultaneously, herb communities gradually decreased in the vegetation reaching a minimum similar to 11.8 cal. ka BP. A gradual decrease of algae remains suggests a reduction of shallow-water habitats. Shrubby and graminoid tundra was dominant similar to 11.8-11.1 cal. ka BP, later Salix stands significantly decreased. The forest-tundra ecotone established in the Early Holocene, shortly after 11.1 cal. ka BP. Low contents of green algae in the Early Holocene sediments likely reflect deeper aquatic conditions. The most favourable climate conditions were between similar to 10.6 and 7 cal. ka BP. Vegetation became similar to the modern after similar to 7 cal. ka BP but Pinus pumila came to the Ilirney area at about 1.2 cal. ka BP. It is important to emphasize that the study area provided refugia for Betula and Alnus during MIS 2. It is also notable that our records do not reflect evidence of Younger Dryas cooling, which is inconsistent with some regional environmental records but in good accordance with some others.},
  language  = {en}
}
@article{CourtinAndreevRaschkeetal.2021,
  author    = {Courtin, J{\´e}r{\´e}my and Andreev, Andrei and Raschke, Elena and Bala, Sarah and Biskaborn, Boris and Liu, Sisi and Zimmermann, Heike and Diekmann, Bernhard and Stoof-Leichsenring, Kathleen R. and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike},
  title     = {Vegetation changes in Southeastern Siberia during the late pleistocene and the holocene},
  series = {Frontiers in Ecology and Evolution},
  volume    = {9},
  journal   = {Frontiers in Ecology and Evolution},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2296-701X},
  doi       = {10.3389/fevo.2021.625096},
  pages     = {18},
  year      = {2021},
  abstract  = {Relationships between climate, species composition, and species richness are of particular importance for understanding how boreal ecosystems will respond to ongoing climate change. This study aims to reconstruct changes in terrestrial vegetation composition and taxa richness during the glacial Late Pleistocene and the interglacial Holocene in the sparsely studied southeastern Yakutia (Siberia) by using pollen and sedimentary ancient DNA (sedaDNA) records. Pollen and sedaDNA metabarcoding data using the trnL g and h markers were obtained from a sediment core from Lake Bolshoe Toko. Both proxies were used to reconstruct the vegetation composition, while metabarcoding data were also used to investigate changes in plant taxa richness. The combination of pollen and sedaDNA approaches allows a robust estimation of regional and local past terrestrial vegetation composition around Bolshoe Toko during the last similar to 35,000 years. Both proxies suggest that during the Late Pleistocene, southeastern Siberia was covered by open steppe-tundra dominated by graminoids and forbs with patches of shrubs, confirming that steppe-tundra extended far south in Siberia. Both proxies show disturbance at the transition between the Late Pleistocene and the Holocene suggesting a period with scarce vegetation, changes in the hydrochemical conditions in the lake, and in sedimentation rates. Both proxies document drastic changes in vegetation composition in the early Holocene with an increased number of trees and shrubs and the appearance of new tree taxa in the lake's vicinity. The sedaDNA method suggests that the Late Pleistocene steppe-tundra vegetation supported a higher number of terrestrial plant taxa than the forested Holocene. This could be explained, for example, by the "keystone herbivore" hypothesis, which suggests that Late Pleistocene megaherbivores were able to maintain a high plant diversity. This is discussed in the light of the data with the broadly accepted species-area hypothesis as steppe-tundra covered such an extensive area during the Late Pleistocene.},
  language  = {en}
}
@article{GluecklerHerzschuhKruseetal.2021,
  author    = {Gl{\"u}ckler, Ramesh and Herzschuh, Ulrike and Kruse, Stefan and Andreev, Andrei and Vyse, Stuart Andrew and Winkler, Bettina and Biskaborn, Boris and Pestryakova, Luidmila Agafyevna and Dietze, Elisabeth},
  title     = {Wildfire history of the boreal forest of south-western Yakutia (Siberia) over the last two millennia documented by a lake-sediment charcoal record},
  series = {Biogeosciences : BG / European Geosciences Union},
  volume    = {18},
  journal   = {Biogeosciences : BG / European Geosciences Union},
  number    = {13},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1726-4170},
  doi       = {10.5194/bg-18-4185-2021},
  pages     = {4185 -- 4209},
  year      = {2021},
  abstract  = {Wildfires, as a key disturbance in forest ecosystems, are shaping the world's boreal landscapes. Changes in fire regimes are closely linked to a wide array of environmental factors, such as vegetation composition, climate change, and human activity. Arctic and boreal regions and, in particular, Siberian boreal forests are experiencing rising air and ground temperatures with the subsequent degradation of permafrost soils leading to shifts in tree cover and species composition. Compared to the boreal zones of North America or Europe, little is known about how such environmental changes might influence long-term fire regimes in Russia. The larch-dominated eastern Siberian deciduous boreal forests differ markedly from the composition of other boreal forests, yet data about past fire regimes remain sparse. Here, we present a high-resolution macroscopic charcoal record from lacustrine sediments of Lake Khamra (southwest Yakutia, Siberia) spanning the last ca. 2200 years, including information about charcoal particle sizes and morphotypes. Our results reveal a phase of increased charcoal accumulation between 600 and 900 CE, indicative of relatively high amounts of burnt biomass and high fire frequencies. This is followed by an almost 900-year-long period of low charcoal accumulation without significant peaks likely corresponding to cooler climate conditions. After 1750 CE fire frequencies and the relative amount of biomass burnt start to increase again, coinciding with a warming climate and increased anthropogenic land development after Russian colonization. In the 20th century, total charcoal accumulation decreases again to very low levels despite higher fire frequency, potentially reflecting a change in fire management strategies and/or a shift of the fire regime towards more frequent but smaller fires. A similar pattern for different charcoal morphotypes and comparison to a pollen and non-pollen palynomorph (NPP) record from the same sediment core indicate that broad-scale changes in vegetation composition were probably not a major driver of recorded fire regime changes. Instead, the fire regime of the last two millennia at Lake Khamra seems to be controlled mainly by a combination of short-term climate variability and anthropogenic fire ignition and suppression.},
  language  = {en}
}
@article{LiuStoofLeichsenringKruseetal.2020,
  author    = {Liu, Sisi and Stoof-Leichsenring, Kathleen Rosemarie and Kruse, Stefan and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike},
  title     = {Holocene vegetation and plant diversity changes in the north-eastern Siberian treeline region from pollen and sedimentary ancient DNA},
  series = {Frontiers in Ecology and Evolution},
  volume    = {8},
  journal   = {Frontiers in Ecology and Evolution},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2296-701X},
  doi       = {10.3389/fevo.2020.560243},
  pages     = {17},
  year      = {2020},
  abstract  = {Although sedimentary ancient DNA (sedaDNA) has been increasingly used to study paleoecological dynamics (Schulte et al., 2020), the approach has rarely been compared with the traditional method of pollen analysis for investigating past changes in the vegetation composition and diversity of Arctic treeline areas. Here, we provide a history of latitudinal floristic composition and species diversity based on a comparison ofsedaDNA and pollen data archived in three Siberian lake sediment cores spanning the mid-Holocene to the present (7.6-0 cal ka BP), from northern typical tundra to southern open larch forest in the Omoloy region. Our results show that thesedaDNA approach identifies more plant taxa found in the local vegetation communities, while the corresponding pollen analysis mainly captures the regional vegetation development and has its limitations for plant diversity reconstruction. Measures of alpha diversity were calculated based onsedaDNA data recovered from along a tundra to forest tundra to open larch forest gradient. Across all sites,sedaDNA archives provide a complementary record of the vegetation transition within each lake's catchment, tracking a distinct latitudinal vegetation type range from larch tree/alder shrub (open larch forest site) to dwarf shrub-steppe (forest tundra) to wet sedge tundra (typical tundra site). By contrast, the pollen data reveal an open landscape, which cannot distinguish the temporal changes in compositional vegetation for the open larch forest site and forest-tundra site. IncreasingLarixpollen percentages were recorded in the forest-tundra site in the last millenium although noLarixDNA was detected, suggesting that thesedaDNA approach performs better for tracking the local establishment ofLarix. Highest species richness and diversity are found in the mid-Holocene (before 4.4 ka) at the typical tundra site with a diverse range of vegetational habitats, while lowest species richness is recorded for the forest tundra where dwarf-willow habitats dominated the lake's catchment. During the late Holocene, strong declines in species richness and diversity are found at the typical tundra site with the vegetation changing to relatively simple communities. Nevertheless, plant species richness is mostly higher than at the forest-tundra site, which shows a slightly decreasing trend. Plant species richness at the open larch forest site fluctuates through time and is higher than the other sites since around 2.5 ka. Taken together, there is no evidence to suggest that the latitudinal gradients in species diversity changes are present at a millennial scale. Additionally, a weak correlation between the principal component analysis (PCA) site scores ofsedaDNA and species richness suggests that climate may not be a direct driver of species turnover within a lake's catchment. Our data suggest thatsedaDNA and pollen have different but complementary abilities for reconstructing past vegetation and species diversity along a latitude.},
  language  = {en}
}
@article{MiesnerHerzschuhPestryakovaetal.2022,
  author    = {Miesner, Timon and Herzschuh, Ulrike and Pestryakova, Luidmila Agafyevna and Wieczorek, Mareike and Zakharov, Evgenii S. and Kolmogorov, Alexei I. and Davydova, Paraskovya V. and Kruse, Stefan},
  title     = {Forest structure and individual tree inventories of northeastern Siberia along climatic gradients},
  series = {Earth system science data : ESSD},
  volume    = {14},
  journal   = {Earth system science data : ESSD},
  number    = {12},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1866-3508},
  doi       = {10.5194/essd-14-5695-2022},
  pages     = {5695 -- 5716},
  year      = {2022},
  abstract  = {We compile a data set of forest surveys from expeditions to the northeast of the Russian Federation, in Krasnoyarsk Krai, the Republic of Sakha (Yakutia), and the Chukotka Autonomous Okrug (59-73 degrees N, 97-169 degrees E), performed between the years 2011 and 2021. The region is characterized by permafrost soils and forests dominated by larch (Larix gmelinii Rupr. and Larix cajanderi Mayr). Our data set consists of a plot database describing 226 georeferenced vegetation survey plots and a tree database with information about all the trees on these plots. The tree database, consisting of two tables with the same column names, contains information on the height, species, and vitality of 40 289 trees. A subset of the trees was subject to a more detailed inventory, which recorded the stem diameter at base and at breast height, crown diameter, and height of the beginning of the crown. We recorded heights up to 28.5 m (median 2.5 m) and stand densities up to 120 000 trees per hectare (median 1197 ha(-1)), with both values tending to be higher in the more southerly areas. Observed taxa include Larix Mill., Pinus L., Picea A. Dietr., Abies Mill., Salix L., Betula L., Populus L., Alnus Mill., and Ulmus L. In this study, we present the forest inventory data aggregated per plot. Additionally, we connect the data with different remote sensing data products to find out how accurately forest structure can be predicted from such products. Allometries were calculated to obtain the diameter from height measurements for every species group. For Larix, the most frequent of 10 species groups, allometries depended also on the stand density, as denser stands are characterized by thinner trees, relative to height. The remote sensing products used to compare against the inventory data include climate, forest biomass, canopy height, and forest loss or disturbance. We find that the forest metrics measured in the field can only be reconstructed from the remote sensing data to a limited extent, as they depend on local properties. This illustrates the need for ground inventories like those data we present here. The data can be used for studying the forest structure of northeastern Siberia and for the calibration and validation of remotely sensed data.},
  language  = {en}
}
@misc{StoofLeichsenringPestryakovaEppetal.2020,
  author    = {Stoof-Leichsenring, Kathleen Rosemarie and Pestryakova, Luidmila Agafyevna and Epp, Laura Saskia and Herzschuh, Ulrike},
  title     = {Phylogenetic diversity and environment form assembly rules for Arctic diatom genera},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {5},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-51548},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515485},
  pages     = {16},
  year      = {2020},
  abstract  = {Aim This study investigates taxonomic and phylogenetic diversity in diatom genera to evaluate assembly rules for eukaryotic microbes across the Siberian tree line. We first analysed how phylogenetic distance relates to taxonomic richness and turnover. Second, we used relatedness indices to evaluate if environmental filtering or competition influences the assemblies in space and through time. Third, we used distance-based ordination to test which environmental variables shape diatom turnover. Location Yakutia and Taymyria, Russia: we sampled 78 surface sediments and a sediment core, extending to 7,000 years before present, to capture the forest-tundra transition in space and time respectively. Taxon Arctic freshwater diatoms. Methods We applied metabarcoding to retrieve diatom diversity from surface and core sedimentary DNA. The taxonomic assignment binned sequence types (lineages) into genera and created taxonomic (abundance of lineages within different genera) and phylogenetic datasets (phylogenetic distances of lineages within different genera). Results Contrary to our expectations, we find a unimodal relationship between phylogenetic distance and richness in diatom genera. We discern a positive relationship between phylogenetic distance and taxonomic turnover in spatially and temporally distributed diatom genera. Furthermore, we reveal positive relatedness indices in diatom genera across the spatial environmental gradient and predominantly in time slices at a single location, with very few exceptions assuming effects of competition. Distance-based ordination of taxonomic and phylogenetic turnover indicates that lake environment variables, like HCO3- and water depth, largely explain diatom turnover. Main conclusion Phylogenetic and abiotic assembly rules are important in understanding the regional assembly of diatom genera across lakes in the Siberian tree line ecotone. Using a space-time approach we are able to exclude the influence of geography and elucidate that lake environmental variables primarily shape the assemblies. We conclude that some diatom genera have greater capabilities to adapt to environmental changes, whereas others will be putatively replaced or lost due to the displacement of the Arctic tundra biome under recent global warming.},
  language  = {en}
}
@article{StoofLeichsenringPestryakovaEppetal.2020,
  author    = {Stoof-Leichsenring, Kathleen Rosemarie and Pestryakova, Luidmila Agafyevna and Epp, Laura Saskia and Herzschuh, Ulrike},
  title     = {Phylogenetic diversity and environment form assembly rules for Arctic diatom genera},
  series = {Journal of Biogeography},
  volume    = {47},
  journal   = {Journal of Biogeography},
  number    = {5},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  issn      = {0305-0270},
  doi       = {10.1111/jbi.13786},
  pages     = {1166 -- 1179},
  year      = {2020},
  abstract  = {Aim This study investigates taxonomic and phylogenetic diversity in diatom genera to evaluate assembly rules for eukaryotic microbes across the Siberian tree line. We first analysed how phylogenetic distance relates to taxonomic richness and turnover. Second, we used relatedness indices to evaluate if environmental filtering or competition influences the assemblies in space and through time. Third, we used distance-based ordination to test which environmental variables shape diatom turnover. Location Yakutia and Taymyria, Russia: we sampled 78 surface sediments and a sediment core, extending to 7,000 years before present, to capture the forest-tundra transition in space and time respectively. Taxon Arctic freshwater diatoms. Methods We applied metabarcoding to retrieve diatom diversity from surface and core sedimentary DNA. The taxonomic assignment binned sequence types (lineages) into genera and created taxonomic (abundance of lineages within different genera) and phylogenetic datasets (phylogenetic distances of lineages within different genera). Results Contrary to our expectations, we find a unimodal relationship between phylogenetic distance and richness in diatom genera. We discern a positive relationship between phylogenetic distance and taxonomic turnover in spatially and temporally distributed diatom genera. Furthermore, we reveal positive relatedness indices in diatom genera across the spatial environmental gradient and predominantly in time slices at a single location, with very few exceptions assuming effects of competition. Distance-based ordination of taxonomic and phylogenetic turnover indicates that lake environment variables, like HCO3- and water depth, largely explain diatom turnover. Main conclusion Phylogenetic and abiotic assembly rules are important in understanding the regional assembly of diatom genera across lakes in the Siberian tree line ecotone. Using a space-time approach we are able to exclude the influence of geography and elucidate that lake environmental variables primarily shape the assemblies. We conclude that some diatom genera have greater capabilities to adapt to environmental changes, whereas others will be putatively replaced or lost due to the displacement of the Arctic tundra biome under recent global warming.},
  language  = {en}
}
@article{vonHippelStoofLeichsenringSchulteetal.2022,
  author    = {von Hippel, Barbara and Stoof-Leichsenring, Kathleen R. and Schulte, Luise and Seeber, Peter Andreas and Epp, Laura Saskia and Biskaborn, Boris and Diekmann, Bernhard and Melles, Martin and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike},
  title     = {Long-term funguseplant covariation from multi-site sedimentary ancient DNA metabarcoding},
  series = {Quaternary science reviews : the international multidisciplinary research and review journal},
  volume    = {295},
  journal   = {Quaternary science reviews : the international multidisciplinary research and review journal},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0277-3791},
  doi       = {10.1016/j.quascirev.2022.107758},
  pages     = {18},
  year      = {2022},
  abstract  = {Climate change has a major impact on arctic and boreal terrestrial ecosystems as warming leads to northward treeline shifts, inducing consequences for heterotrophic organisms associated with the plant taxa. To unravel ecological dependencies, we address how long-term climatic changes have shaped the co-occurrence of plants and fungi across selected sites in Siberia. We investigated sedimentary ancient DNA from five lakes spanning the last 47,000 years, using the ITS1 marker for fungi and the chloroplast P6 loop marker for vegetation metabarcoding. We obtained 706 unique fungal operational taxonomic units (OTUs) and 243 taxa for the plants. We show higher OTU numbers in dry forest tundra as well as boreal forests compared to wet southern tundra. The most abundant fungal taxa in our dataset are Pseudeurotiaceae, Mortierella, Sordariomyceta, Exophiala, Oidiodendron, Protoventuria, Candida vartiovaarae, Pseudeurotium, Gryganskiella fimbricystis, and Tricho-sporiella cerebriformis. The overall fungal composition is explained by the plant composition as revealed by redundancy analysis. The fungal functional groups show antagonistic relationships in their climate susceptibility. The advance of woody taxa in response to past warming led to an increase in the abun-dance of mycorrhizae, lichens, and parasites, while yeast and saprotroph distribution declined. We also show co-occurrences between Salicaceae, Larix, and Alnus and their associated pathogens and detect higher mycorrhizal fungus diversity with the presence of Pinaceae. Under future warming, we can expect feedbacks between fungus composition and plant diversity changes which will affect forest advance, species diversity, and ecosystem stability in arctic regions.},
  language  = {en}
}