TY - JOUR
A1 - Glückler, Ramesh
A1 - Herzschuh, Ulrike
A1 - Kruse, Stefan
A1 - Andreev, Andrei
A1 - Vyse, Stuart Andrew
A1 - Winkler, Bettina
A1 - Biskaborn, Boris
A1 - Pestryakova, Luidmila Agafyevna
A1 - Dietze, Elisabeth
T1 - Wildfire history of the boreal forest of south-western Yakutia (Siberia) over the last two millennia documented by a lake-sediment charcoal record
JF - Biogeosciences : BG / European Geosciences Union
N2 - 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.
Y1 - 2021
U6 - https://doi.org/10.5194/bg-18-4185-2021
SN - 1726-4170
SN - 1726-4189
VL - 18
IS - 13
SP - 4185
EP - 4209
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Kruse, Stefan
A1 - Wieczorek, Mareike
A1 - Jeltsch, Florian
A1 - Herzschuh, Ulrike
T1 - Treeline dynamics in Siberia under changing climates as inferred from an individual-based model for Larix
JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog
KW - Forest change
KW - IBM
KW - ODD model description
KW - Larix gmelinii
KW - Permafrost ecosystem
KW - Time-lag effects
Y1 - 2016
U6 - https://doi.org/10.1016/j.ecolmodel.2016.08.003
SN - 0304-3800
SN - 1872-7026
VL - 338
SP - 101
EP - 121
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Stuenzi, Simone Maria
A1 - Kruse, Stefan
A1 - Boike, Julia
A1 - Herzschuh, Ulrike
A1 - Oehme, Alexander
A1 - Pestryakova, Luidmila A.
A1 - Westermann, Sebastian
A1 - Langer, Moritz
T1 - Thermohydrological impact of forest disturbances on ecosystem-protected permafrost
JF - Journal of geophysical research : Biogeosciences
N2 - Boreal forests cover over half of the global permafrost area and protect underlying permafrost. Boreal forest development, therefore, has an impact on permafrost evolution, especially under a warming climate.
Forest disturbances and changing climate conditions cause vegetation shifts and potentially destabilize the carbon stored within the vegetation and permafrost. Disturbed permafrost-forest ecosystems can develop into a dry or swampy bush- or grasslands, shift toward broadleaf- or evergreen needleleaf-dominated forests, or recover to the pre-disturbance state.
An increase in the number and intensity of fires, as well as intensified logging activities, could lead to a partial or complete ecosystem and permafrost degradation. We study the impact of forest disturbances (logging, surface, and canopy fires) on the thermal and hydrological permafrost conditions and ecosystem resilience.
We use a dynamic multilayer canopy-permafrost model to simulate different scenarios at a study site in eastern Siberia. We implement expected mortality, defoliation, and ground surface changes and analyze the interplay between forest recovery and permafrost. We find that forest loss induces soil drying of up to 44%, leading to lower active layer thicknesses and abrupt or steady decline of a larch forest, depending on disturbance intensity.
Only after surface fires, the most common disturbances, inducing low mortality rates, forests can recover and overpass pre-disturbance leaf area index values. We find that the trajectory of larch forests after surface fires is dependent on the precipitation conditions in the years after the disturbance. Dryer years can drastically change the direction of the larch forest development within the studied period.
KW - permafrost
KW - boreal forest
KW - periglacial process
KW - Siberia
KW - larch forest
KW - disturbance
Y1 - 2022
U6 - https://doi.org/10.1029/2021JG006630
SN - 2169-8953
SN - 2169-8961
VL - 127
IS - 5
PB - American Geophysical Union
CY - Washington
ER -
TY - JOUR
A1 - Epp, Laura Saskia
A1 - Kruse, Stefan
A1 - Kath, Nadja J.
A1 - Stoof-Leichsenring, Kathleen Rosemarie
A1 - Tiedemann, Ralph
A1 - Pestryakova, Luidmila Agafyevna
A1 - Herzschuh, Ulrike
T1 - Temporal and spatial patterns of mitochondrial haplotype and species distributions in Siberian larches inferred from ancient environmental DNA and modeling
JF - Scientific reports
N2 - Changes in species’ distributions are classically projected based on their climate envelopes. For Siberian forests, which have a tremendous significance for vegetation-climate feedbacks, this implies future shifts of each of the forest-forming larch (Larix) species to the north-east. However, in addition to abiotic factors, reliable projections must assess the role of historical biogeography and biotic interactions. Here, we use sedimentary ancient DNA and individual-based modelling to investigate the distribution of larch species and mitochondrial haplotypes through space and time across the treeline ecotone on the southern Taymyr peninsula, which at the same time presents a boundary area of two larch species. We find spatial and temporal patterns, which suggest that forest density is the most influential driver determining the precise distribution of species and mitochondrial haplotypes. This suggests a strong influence of competition on the species’ range shifts. These findings imply possible climate change outcomes that are directly opposed to projections based purely on climate envelopes. Investigations of such fine-scale processes of biodiversity change through time are possible using paleoenvironmental DNA, which is available much more readily than visible fossils and can provide information at a level of resolution that is not reached in classical palaeoecology.
Y1 - 2018
U6 - https://doi.org/10.1038/s41598-018-35550-w
SN - 2045-2322
VL - 8
PB - Nature Publ. Group
CY - London
ER -
TY - JOUR
A1 - Heim, Birgit
A1 - Lisovski, Simeon
A1 - Wieczorek, Mareike
A1 - Morgenstern, Anne
A1 - Juhls, Bennet
A1 - Shevtsova, Iuliia
A1 - Kruse, Stefan
A1 - Boike, Julia
A1 - Fedorova, Irina
A1 - Herzschuh, Ulrike
T1 - Spring snow cover duration and tundra greenness in the Lena Delta, Siberia
BT - two decades of MODIS satellite time series (2001-2021)
JF - Environmental research letters
N2 - The Lena Delta in Siberia is the largest delta in the Arctic and as a snow-dominated ecosystem particularly vulnerable to climate change.
Using the two decades of MODerate resolution Imaging Spectroradiometer satellite acquisitions, this study investigates interannual and spatial variability of snow-cover duration and summer vegetation vitality in the Lena Delta.
We approximated snow by the application of the normalized difference snow index and vegetation greenness by the normalized difference vegetation index (NDVI). We consolidated the analyses by integrating reanalysis products on air temperature from 2001 to 2021, and air temperature, ground temperature, and the date of snow-melt from time-lapse camera (TLC) observations from the Samoylov observatory located in the central delta.
We extracted spring snow-cover duration determined by a latitudinal gradient. The 'regular year' snow-melt is transgressing from mid-May to late May within a time window of 10 days across the delta.
We calculated yearly deviations per grid cell for two defined regions, one for the delta, and one focusing on the central delta. We identified an ensemble of early snow-melt years from 2012 to 2014, with snow-melt already starting in early May, and two late snow-melt years in 2004 and 2017, with snow-melt starting in June. In the times of TLC recording, the years of early and late snow-melt were confirmed.
In the three summers after early snow-melt, summer vegetation greenness showed neither positive nor negative deviations. Whereas, vegetation greenness was reduced in 2004 after late snow-melt together with the lowest June monthly air temperature of the time series record. Since 2005, vegetation greenness is rising, with maxima in 2018 and 2021.
The NDVI rise since 2018 is preceded by up to 4 degrees C warmer than average June air temperature. The ongoing operation of satellite missions allows to monitor a wide range of land surface properties and processes that will provide urgently needed data in times when logistical challenges lead to data gaps in land-based observations in the rapidly changing Arctic.
KW - Arctic vegetation
KW - tundra
KW - snow cover duration
KW - NDVI
KW - NDSI
KW - MODIS
KW - Lena Delta
Y1 - 2022
U6 - https://doi.org/10.1088/1748-9326/ac8066
SN - 1748-9326
VL - 17
IS - 8
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - van Geffen, Femke
A1 - Heim, Birgit
A1 - Brieger, Frederic
A1 - Geng, Rongwei
A1 - Shevtsova, Iuliia
A1 - Schulte, Luise
A1 - Stuenzi, Simone M.
A1 - Bernhardt, Nadine
A1 - Troeva, Elena I.
A1 - Pestryakova, Luidmila Agafyevna
A1 - Zakharov, Evgenii S.
A1 - Pflug, Bringfried
A1 - Herzschuh, Ulrike
A1 - Kruse, Stefan
T1 - SiDroForest: a comprehensive forest inventory of Siberian boreal forest investigations including drone-based point clouds, individually labeled trees, synthetically generated tree crowns, and Sentinel-2 labeled image patches
JF - Earth system science data
N2 - The SiDroForest (Siberian drone-mapped forest inventory) data collection is an attempt to remedy the scarcity of forest structure data in the circumboreal region by providing adjusted and labeled tree-level and vegetation plot-level data for machine learning and upscaling purposes. We present datasets of vegetation composition and tree and plot level forest structure for two important vegetation transition zones in Siberia, Russia; the summergreen-evergreen transition zone in Central Yakutia and the tundra-taiga transition zone in Chukotka (NE Siberia). The SiDroForest data collection consists of four datasets that contain different complementary data types that together support in-depth analyses from different perspectives of Siberian Forest plot data for multi-purpose applications. i. Dataset 1 provides unmanned aerial vehicle (UAV)-borne data products covering the vegetation plots surveyed during fieldwork (Kruse et al., 2021, ). The dataset includes structure-from-motion (SfM) point clouds and red-green-blue (RGB) and red-green-near-infrared (RGN) orthomosaics. From the orthomosaics, point-cloud products were created such as the digital elevation model (DEM), canopy height model (CHM), digital surface model (DSM) and the digital terrain model (DTM). The point-cloud products provide information on the three-dimensional (3D) structure of the forest at each plot. Dataset 2 contains spatial data in the form of point and polygon shapefiles of 872 individually labeled trees and shrubs that were recorded during fieldwork at the same vegetation plots (van Geffen et al., 2021c, ). The dataset contains information on tree height, crown diameter, and species type. These tree and shrub individually labeled point and polygon shapefiles were generated on top of the RGB UVA orthoimages. The individual tree information collected during the expedition such as tree height, crown diameter, and vitality are provided in table format. This dataset can be used to link individual information on trees to the location of the specific tree in the SfM point clouds, providing for example, opportunity to validate the extracted tree height from the first dataset. The dataset provides unique insights into the current state of individual trees and shrubs and allows for monitoring the effects of climate change on these individuals in the future. Dataset 3 contains a synthesis of 10 000 generated images and masks that have the tree crowns of two species of larch ( and ) automatically extracted from the RGB UAV images in the common objects in context (COCO) format (van Geffen et al., 2021a, ). As machine-learning algorithms need a large dataset to train on, the synthetic dataset was specifically created to be used for machine-learning algorithms to detect Siberian larch species. Larix gmeliniiLarix cajanderiDataset 4 contains Sentinel-2 (S-2) Level-2 bottom-of-atmosphere processed labeled image patches with seasonal information and annotated vegetation categories covering the vegetation plots (van Geffen et al., 2021b, ). The dataset is created with the aim of providing a small ready-to-use validation and training dataset to be used in various vegetation-related machine-learning tasks. It enhances the data collection as it allows classification of a larger area with the provided vegetation classes. The SiDroForest data collection serves a variety of user communities.
The detailed vegetation cover and structure information in the first two datasets are of use for ecological applications, on one hand for summergreen and evergreen needle-leaf forests and also for tundra-taiga ecotones. Datasets 1 and 2 further support the generation and validation of land cover remote-sensing products in radar and optical remote sensing. In addition to providing information on forest structure and vegetation composition of the vegetation plots, the third and fourth datasets are prepared as training and validation data for machine-learning purposes. For example, the synthetic tree-crown dataset is generated from the raw UAV images and optimized to be used in neural networks. Furthermore, the fourth SiDroForest dataset contains S-2 labeled image patches processed to a high standard that provide training data on vegetation class categories for machine-learning classification with JavaScript Object Notation (JSON) labels provided. The SiDroForest data collection adds unique insights into remote hard-to-reach circumboreal forest regions.
Y1 - 2022
U6 - https://doi.org/10.5194/essd-14-4967-2022
SN - 1866-3508
SN - 1866-3516
VL - 14
IS - 11
SP - 4967
EP - 4994
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Jia, Weihan
A1 - Anslan, Sten
A1 - Chen, Fahu
A1 - Cao, Xianyong
A1 - Dong, Hailiang
A1 - Dulias, Katharina
A1 - Gu, Zhengquan
A1 - Heinecke, Liv
A1 - Jiang, Hongchen
A1 - Kruse, Stefan
A1 - Kang, Wengang
A1 - Li, Kai
A1 - Liu, Sisi
A1 - Liu, Xingqi
A1 - Liu, Ying
A1 - Ni, Jian
A1 - Schwalb, Antje
A1 - Stoof-Leichsenring, Kathleen R.
A1 - Shen, Wei
A1 - Tian, Fang
A1 - Wang, Jing
A1 - Wang, Yongbo
A1 - Wang, Yucheng
A1 - Xu, Hai
A1 - Yang, Xiaoyan
A1 - Zhang, Dongju
A1 - Herzschuh, Ulrike
T1 - Sedimentary ancient DNA reveals past ecosystem and biodiversity changes on the Tibetan Plateau: overview and prospects
JF - Quaternary science reviews : the international multidisciplinary research and review journal
N2 - Alpine ecosystems on the Tibetan Plateau are being threatened by ongoing climate warming and intensified human activities. Ecological time-series obtained from sedimentary ancient DNA (sedaDNA) are essential for understanding past ecosystem and biodiversity dynamics on the Tibetan Plateau and their responses to climate change at a high taxonomic resolution. Hitherto only few but promising studies have been published on this topic. The potential and limitations of using sedaDNA on the Tibetan Plateau are not fully understood. Here, we (i) provide updated knowledge of and a brief introduction to the suitable archives, region-specific taphonomy, state-of-the-art methodologies, and research questions of sedaDNA on the Tibetan Plateau; (ii) review published and ongoing sedaDNA studies from the Tibetan Plateau; and (iii) give some recommendations for future sedaDNA study designs. Based on the current knowledge of taphonomy, we infer that deep glacial lakes with freshwater and high clay sediment input, such as those from the southern and southeastern Tibetan Plateau, may have a high potential for sedaDNA studies. Metabarcoding (for microorganisms and plants), metagenomics (for ecosystems), and hybridization capture (for prehistoric humans) are three primary sedaDNA approaches which have been successfully applied on the Tibetan Plateau, but their power is still limited by several technical issues, such as PCR bias and incompleteness of taxonomic reference databases. Setting up high-quality and open-access regional taxonomic reference databases for the Tibetan Plateau should be given priority in the future. To conclude, the archival, taphonomic, and methodological conditions of the Tibetan Plateau are favorable for performing sedaDNA studies. More research should be encouraged to address questions about long-term ecological dynamics at ecosystem scale and to bring the paleoecology of the Tibetan Plateau into a new era.
KW - Sedimentary ancient DNA (sedaDNA)
KW - Tibetan Plateau
KW - Environmental DNA
KW - Taphonomy
KW - Ecosystem
KW - Biodiversity
KW - Paleoecology
KW - Paleogeography
Y1 - 2022
U6 - https://doi.org/10.1016/j.quascirev.2022.107703
SN - 0277-3791
SN - 1873-457X
VL - 293
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Zimmermann, Heike
A1 - Stoof-Leichsenring, Kathleen R.
A1 - Kruse, Stefan
A1 - Nürnberg, Dirk
A1 - Tiedemann, Ralf
A1 - Herzschuh, Ulrike
T1 - Sedimentary ancient DNA from the subarctic North Pacific
BT - How sea ice, salinity, and insolation dynamics have shaped diatom composition and richness over the past 20,000 years
JF - Paleoceanography and paleoclimatology
N2 - We traced diatom composition and diversity through time using diatom-derived sedimentary ancient DNA (sedaDNA) from eastern continental slope sediments off Kamchatka (North Pacific) by applying a short, diatom-specific marker on 63 samples in a DNA metabarcoding approach. The sequences were assigned to diatoms that are common in the area and characteristic of cold water. SedaDNA allowed us to observe shifts of potential lineages from species of the genus Chaetoceros that can be related to different climatic phases, suggesting that pre-adapted ecotypes might have played a role in the long-term success of species in areas of changing environmental conditions. These sedaDNA results complement our understanding of the long-term history of diatom assemblages and their general relationship to environmental conditions of the past. Sea-ice diatoms (Pauliella taeniata [Grunow] Round & Basson, Attheya septentrionalis [ostrup] R. M. Crawford and Nitzschia frigida [Grunow]) detected during the late glacial and Younger Dryas are in agreement with previous sea-ice reconstructions. A positive correlation between pennate diatom richness and the sea-ice proxy IP25 suggests that sea ice fosters pennate diatom richness, whereas a negative correlation with June insolation and temperature points to unfavorable conditions during the Holocene. A sharp increase in proportions of freshwater diatoms at similar to 11.1 cal kyr BP implies the influence of terrestrial runoff and coincides with the loss of 42% of diatom sequence variants. We assume that reduced salinity at this time stabilized vertical stratification which limited the replenishment of nutrients in the euphotic zone.
KW - Bacillariophyceae
KW - DNA metabarcoding
KW - glacial / interglacial transition
KW - northwestern Pacific
KW - richness
KW - sedaDNA
Y1 - 2021
U6 - https://doi.org/10.1029/2020PA004091
SN - 2572-4525
VL - 36
IS - 4
PB - Wiley
CY - Hoboken, NJ
ER -
TY - JOUR
A1 - Herzschuh, Ulrike
A1 - Böhmer, Thomas
A1 - Li, Chenzhi
A1 - Cao, Xianyong
A1 - Hébert, Raphaël
A1 - Dallmeyer, Anne
A1 - Telford, Richard J.
A1 - Kruse, Stefan
T1 - Reversals in temperature-precipitation correlations in the Northern Hemisphere extratropics during the Holocene
JF - Geophysical research letters
N2 - Future precipitation levels remain uncertain because climate models have struggled to reproduce observed variations in temperature-precipitation correlations. Our analyses of Holocene proxy-based temperature-precipitation correlations and hydrological sensitivities from 2,237 Northern Hemisphere extratropical pollen records reveal a significant latitudinal dependence and temporal variations among the early, middle, and late Holocene. These proxy-based variations are largely consistent with patterns obtained from transient climate simulations (TraCE21k). While high latitudes and subtropical monsoon areas show mainly stable positive correlations throughout the Holocene, the mid-latitude pattern is temporally and spatially more variable. In particular, we identified a reversal from positive to negative temperature-precipitation correlations in the eastern North American and European mid-latitudes from the early to mid-Holocene that mainly related to slowed down westerlies and a switch to moisture-limited convection under a warm climate. Our palaeoevidence of past temperature-precipitation correlation shifts identifies those regions where simulating past and future precipitation levels might be particularly challenging.
Y1 - 2022
U6 - https://doi.org/10.1029/2022GL099730
SN - 0094-8276
SN - 1944-8007
VL - 49
IS - 22
PB - American Geophysical Union
CY - Washington
ER -
TY - JOUR
A1 - Kruse, Stefan
A1 - Herzschuh, Ulrike
T1 - Regional opportunities for tundra conservation in the next 1000 years
JF - eLife
N2 - The biodiversity of tundra areas in northern high latitudes is threatened by invasion of forests under global warming. However, poorly understood nonlinear responses of the treeline ecotone mean the timing and extent of tundra losses are unclear, but policymakers need such information to optimize conservation efforts. Our individual-based model LAVESI, developed for the Siberian tundra-taiga ecotone, can help improve our understanding. Consequently, we simulated treeline migration trajectories until the end of the millennium, causing a loss of tundra area when advancing north. Our simulations reveal that the treeline follows climate warming with a severe, century-long time lag, which is overcompensated by infilling of stands in the long run even when temperatures cool again. Our simulations reveal that only under ambitious mitigation strategies (relative concentration pathway 2.6) will ~30% of original tundra areas remain in the north but separated into two disjunct refugia.
KW - Larix gmelinii
KW - Larix cajanderi
KW - nonlinear response
KW - treeline ecotone
KW - tundra
KW - Ecology
KW - Short Report
Y1 - 2022
U6 - https://doi.org/10.7554/eLife.75163
SN - 2050-084X
VL - 11
PB - eLife Sciences Publications
CY - Cambridge
ER -
TY - JOUR
A1 - Kruse, Stefan
A1 - Stünzi, Simone Maria
A1 - Boike, Julia
A1 - Langer, Moritz
A1 - Gloy, Josias
A1 - Herzschuh, Ulrike
T1 - Novel coupled permafrost-forest model (LAVESI-CryoGrid v1.0) revealing the interplay between permafrost, vegetation, and climate across eastern Siberia
JF - Geoscientific model development : GMD ; an interactive open access journal of the European Geosciences Union
N2 - Boreal forests of Siberia play a relevant role in the global carbon cycle. However, global warming threatens the existence of summergreen larch-dominated ecosystems, likely enabling a transition to evergreen tree taxa with deeper active layers. Complex permafrost-vegetation interactions make it uncertain whether these ecosystems could develop into a carbon source rather than continuing atmospheric carbon sequestration under global warming. Consequently, shedding light on the role of current and future active layer dynamics and the feedbacks with the apparent tree species is crucial to predict boreal forest transition dynamics and thus for aboveground forest biomass and carbon stock developments. Hence, we established a coupled model version amalgamating a one-dimensional permafrost multilayer forest land-surface model (CryoGrid) with LAVESI, an individual-based and spatially explicit forest model for larch species (Larix Mill.), extended for this study by including other relevant Siberian forest species and explicit terrain.
Following parameterization, we ran simulations with the coupled version to the near future to 2030 with a mild climate-warming scenario. We focus on three regions covering a gradient of summergreen forests in the east at Spasskaya Pad, mixed summergreen-evergreen forests close to Nyurba, and the warmest area at Lake Khamra in the southeast of Yakutia, Russia. Coupled simulations were run with the newly implemented boreal forest species and compared to runs allowing only one species at a time, as well as to simulations using just LAVESI. Results reveal that the coupled version corrects for overestimation of active layer thickness (ALT) and soil moisture, and large differences in established forests are simulated. We conclude that the coupled version can simulate the complex environment of eastern Siberia by reproducing vegetation patterns, making it an excellent tool to disentangle processes driving boreal forest dynamics.
Y1 - 2022
U6 - https://doi.org/10.5194/gmd-15-2395-2022
SN - 1991-959X
SN - 1991-9603
VL - 15
IS - 6
SP - 2395
EP - 2422
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Geng, Rongwei
A1 - Andreev, Andrei
A1 - Kruse, Stefan
A1 - Heim, Birgit
A1 - van Geffen, Femke
A1 - Pestryakova, Luidmila
A1 - Zakharov, Evgenii
A1 - Troeva, Elena I.
A1 - Shevtsova, Iuliia
A1 - Li, Furong
A1 - Zhao, Yan
A1 - Herzschuh, Ulrike
T1 - Modern pollen assemblages from lake sediments and soil in East Siberia and relative pollen productivity estimates for Major Taxa
JF - Frontiers in Ecology and Evolution
N2 - Modern pollen-vegetation-climate relationships underpin palaeovegetation and palaeoclimate reconstructions from fossil pollen records. East Siberia is an ideal area for investigating the relationships between modern pollen assemblages and near natural vegetation under cold continental climate conditions. Reliable pollen-based quantitative vegetation and climate reconstructions are still scarce due to the limited number of modern pollen datasets. Furthermore, differences in pollen representation of samples from lake sediments and soils are not well understood. Here, we present a new pollen dataset of 48 moss/soil and 24 lake surface-sediment samples collected in Chukotka and central Yakutia in East Siberia. The pollen-vegetation-climate relationships were investigated by ordination analyses. Generally, tundra and taiga vegetation types can be well distinguished in the surface pollen assemblages. Moss/soil and lake samples contain generally similar pollen assemblages as revealed by a Procrustes comparison with some exceptions. Overall, modern pollen assemblages reflect the temperature and precipitation gradients in the study areas as revealed by constrained ordination analysis. We estimate the relative pollen productivity (RPP) of major taxa and the relevant source area of pollen (RSAP) for moss/soil samples from Chukotka and central Yakutia using Extended R-Value (ERV) analysis. The RSAP of the tundra-forest transition area in Chukotka and taiga area in central Yakutia are ca. 1300 and 360 m, respectively. For Chukotka, RPPs relative to both Poaceae and Ericaceae were estimated while RPPs for central Yakutia were relative only to Ericaceae. Relative to Ericaceae (reference taxon, RPP = 1), Larix, Betula, Picea, and Pinus are overrepresented while Alnus, Cyperaceae, Poaceae, and Salix are underrepresented in the pollen spectra. Our estimates are in general agreement with previously published values and provide the basis for reliable quantitative reconstructions of East Siberian vegetation.
KW - modern pollen assemblages
KW - pollen-vegetation-climate relationships
KW - East Siberia
KW - tundra
KW - taiga
KW - relative pollen productivity
KW - quantitative vegetation reconstruction
Y1 - 2022
U6 - https://doi.org/10.3389/fevo.2022.837857
SN - 2296-701X
VL - 10
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Kruse, Stefan
A1 - Kolmogorov, Aleksey I.
A1 - Pestryakova, Luidmila Agafyevna
A1 - Herzschuh, Ulrike
T1 - Long-lived larch clones may conserve adaptations that could restrict treeline migration in northern Siberia
JF - Ecology and evolution
N2 - The occurrence of refugia beyond the arctic treeline and genetic adaptation therein play a crucial role of largely unknown effect size. While refugia have potential for rapidly colonizing the tundra under global warming, the taxa may be maladapted to the new environmental conditions. Understanding the genetic composition and age of refugia is thus crucial for predicting any migration response.
Here, we genotype 194 larch individuals from an similar to 1.8 km(2)area in northcentral Siberia on the southern Taimyr Peninsula by applying an assay of 16 nuclear microsatellite markers. For estimating the age of clonal individuals, we counted tree rings at sections along branches to establish a lateral growth rate that was then combined with geographic distance.
Findings reveal that the predominant reproduction type is clonal (58.76%) by short distance spreading of ramets. One outlier of clones 1 km apart could have been dispersed by reindeer. In clonal groups and within individuals, we find that somatic mutations accumulate with geographic distance. Clonal groups of two or more individuals are observed. Clonal age estimates regularly suggest individuals as old as 2,200 years, which coincides with a major environmental change that forced a treeline retreat in the region.
We conclude that individuals with clonal growth mode were naturally selected as it lowers the likely risk of extinction under a harsh environment. We discuss this legacy from the past that might now be a maladaptation and hinder expansion under currently strongly increasing temperatures.
KW - adaptation
KW - clonal growth
KW - growth rate
KW - Larix
KW - leading edge
KW - treeline
KW - migration
Y1 - 2020
U6 - https://doi.org/10.1002/ece3.6660
SN - 2045-7758
VL - 10
IS - 18
SP - 10017
EP - 10030
PB - Wiley
CY - Hoboken
ER -
TY - JOUR
A1 - Andreev, Andrei
A1 - Raschke, Elena
A1 - Biskaborn, Boris
A1 - Vyse, Stuart Andrew
A1 - Courtin, Jérémy
A1 - Böhmer, Thomas
A1 - Stoof-Leichsenring, Kathleen R.
A1 - Kruse, Stefan
A1 - Pestryakova, Luidmila Agafyevna
A1 - Herzschuh, Ulrike
T1 - Late Pleistocene to Holocene vegetation and climate changes in northwestern Chukotka (Far East Russia) deduced from lakes Ilirney and Rauchuagytgyn pollen records
JF - Boreas : an international journal of quaternary research
N2 - 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.
Y1 - 2021
U6 - https://doi.org/10.1111/bor.12521
SN - 0300-9483
SN - 1502-3885
VL - 50
IS - 3
SP - 652
EP - 670
PB - Wiley-Blackwell
CY - Oxford [u.a.]
ER -
TY - JOUR
A1 - Kruse, Stefan
A1 - Gerdes, Alexander
A1 - Kath, Nadja J.
A1 - Herzschuh, Ulrike
T1 - Implementing spatially explicit wind-driven seed and pollen dispersal in the individual-based larch simulation model
BT - LAVESI-WIND 1.0
JF - Geoscientific model development : an interactive open access journal of the European Geosciences Union
N2 - It is of major interest to estimate the feedback of arctic ecosystems to the global warming we expect in upcoming decades. The speed of this response is driven by the potential of species to migrate, tracking their climate optimum. For this, sessile plants have to produce and disperse seeds to newly available habitats, and pollination of ovules is needed for the seeds to be viable. These two processes are also the vectors that pass genetic information through a population. A restricted exchange among subpopulations might lead to a maladapted population due to diversity losses. Hence, a realistic implementation of these dispersal processes into a simulation model would allow an assessment of the importance of diversity for the migration of plant species in various environments worldwide. To date, dynamic global vegetation models have been optimized for a global application and overestimate the migration of biome shifts in currently warming temperatures. We hypothesize that this is caused by neglecting important fine-scale processes, which are necessary to estimate realistic vegetation trajectories. Recently, we built and parameterized a simulation model LAVESI for larches that dominate the latitudinal treelines in the northernmost areas of Siberia. In this study, we updated the vegetation model by including seed and pollen dispersal driven by wind speed and direction. The seed dispersal is modelled as a ballistic flight, and for the pollination of ovules of seeds produced, we implemented a wind-determined and distance-dependent probability distribution function using a von Mises distribution to select the pollen donor. A local sensitivity analysis of both processes supported the robustness of the model's results to the parameterization, although it highlighted the importance of recruitment and seed dispersal traits for migration rates. This individual-based and spatially explicit implementation of both dispersal processes makes it easily feasible to inherit plant traits and genetic information to assess the impact of migration processes on the genetics. Finally, we suggest how the final model can be applied to substantially help in unveiling the important drivers of migration dynamics and, with this, guide the improvement of recent global vegetation models.
Y1 - 2018
U6 - https://doi.org/10.5194/gmd-11-4451-2018
SN - 1991-959X
SN - 1991-9603
VL - 11
IS - 11
SP - 4451
EP - 4467
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Glückler, Ramesh
A1 - Geng, Rongwei
A1 - Grimm, Lennart
A1 - Baisheva, Izabella
A1 - Herzschuh, Ulrike
A1 - Stoof-Leichsenring, Kathleen R.
A1 - Kruse, Stefan
A1 - Andreev, Andrej Aleksandrovic
A1 - Pestryakova, Luidmila
A1 - Dietze, Elisabeth
T1 - Holocene wildfire and vegetation dynamics in Central Yakutia, Siberia, reconstructed from lake-sediment proxies
JF - Frontiers in Ecology and Evolution
N2 - Wildfires play an essential role in the ecology of boreal forests.
In eastern Siberia, fire activity has been increasing in recent years, challenging the livelihoods of local communities. Intensifying fire regimes also increase disturbance pressure on the boreal forests, which currently protect the permafrost beneath from accelerated degradation.
However, long-term relationships between changes in fire regime and forest structure remain largely unknown.
We assess past fire-vegetation feedbacks using sedimentary proxy records from Lake Satagay, Central Yakutia, Siberia, covering the past c. 10,800 years.
Results from macroscopic and microscopic charcoal analyses indicate high amounts of burnt biomass during the Early Holocene, and that the present-day, low-severity surface fire regime has been in place since c. 4,500 years before present.
A pollen-based quantitative reconstruction of vegetation cover and a terrestrial plant record based on sedimentary ancient DNA metabarcoding suggest a pronounced shift in forest structure toward the Late Holocene.
Whereas the Early Holocene was characterized by postglacial open larch-birch woodlands, forest structure changed toward the modern, mixed larch-dominated closed-canopy forest during the Mid-Holocene.
We propose a potential relationship between open woodlands and high amounts of burnt biomass, as well as a mediating effect of dense larch forest on the climate-driven intensification of fire regimes.
Considering the anticipated increase in forest disturbances (droughts, insect invasions, and wildfires), higher tree mortality may force the modern state of the forest to shift toward an open woodland state comparable to the Early Holocene.
Such a shift in forest structure may result in a positive feedback on currently intensifying wildfires.
These new long-term data improve our understanding of millennial-scale fire regime changes and their relationships to changes of vegetation in Central Yakutia, where the local population is already being confronted with intensifying wildfire seasons.
KW - fire
KW - larch
KW - boreal
KW - forest
KW - Russia
KW - charcoal
KW - pollen
KW - ancient DNA
Y1 - 2022
U6 - https://doi.org/10.3389/fevo.2022.962906
SN - 2296-701X
VL - 10
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Liu, Sisi
A1 - Stoof-Leichsenring, Kathleen Rosemarie
A1 - Kruse, Stefan
A1 - Pestryakova, Luidmila Agafyevna
A1 - Herzschuh, Ulrike
T1 - Holocene vegetation and plant diversity changes in the north-eastern Siberian treeline region from pollen and sedimentary ancient DNA
JF - Frontiers in Ecology and Evolution
N2 - 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.
KW - sedimentary ancient DNA
KW - metabarcoding
KW - pollen
KW - Siberia
KW - palaeovegetation
KW - plant diversity
KW - latitudinal gradient
Y1 - 2020
U6 - https://doi.org/10.3389/fevo.2020.560243
SN - 2296-701X
VL - 8
PB - Frontiers Media
CY - Lausanne
ER -
TY - JOUR
A1 - Kruse, Stefan
A1 - Epp, Laura Saskia
A1 - Wieczorek, Mareike
A1 - Pestryakova, Luidmila Agafyevna
A1 - Stoof-Leichsenring, Kathleen Rosemarie
A1 - Herzschuh, Ulrike
T1 - High gene flow and complex treeline dynamics of Larix Mill. stands on the Taymyr Peninsula (north-central Siberia) revealed by nuclear microsatellites
JF - Tree Genetics & Genomes
N2 - Arctic treelines are facing a strong temperature increase as a result of recent global warming, causing possible changes in forest extent, which will alter vegetation-climate feedbacks. However, the mode and strength of the response is rather unclear, as potential changes are happening in areas that are very remote and difficult to access, and empirical data are still largely lacking. Here, we assessed the current population structure and genetic differentiation of Larix Mill. tree stands within the northernmost latitudinal treeline reaching ~ 72° N in the southern lowlands of the Taymyr Peninsula (~ 100° E). We sampled 743 individuals belonging to different height classes (seedlings, saplings, trees) at 11 locations along a gradient from ‘single tree’ tundra over ‘forest line’ to ‘dense forest’ stands and conducted investigations applying eight highly polymorphic nuclear microsatellites. Results suggest a high diversity within sub-populations (HE = 0.826–0.893), coupled, however, with heterozygote deficits in all sub-populations, but pronounced in ‘forest line’ stands. Overall, genetic differentiation of sub-populations is low (FST = 0.005), indicating a region-wide high gene flow, although ‘forest line’ stands harbour few rare and private alleles, likely indicating greater local reproduction. ‘Single tree’ stands, located beyond the northern forest line, are currently not involved in treeline expansion, but show signs of a long-term refuge, namely asexual reproduction and change of growth-form from erect to creeping growth, possibly having persisted for thousands of years. The lack of differentiation between the sub-populations points to a sufficiently high dispersal potential, and thus a rapid northward migration of the Siberian arctic treeline under recent global warming seems potentially unconstrained, but observations show it to be unexpectedly slow.
KW - Larch
KW - Population genetics
KW - Boreal forests
KW - Tundra-taiga transition
KW - Range expansion
Y1 - 2018
U6 - https://doi.org/10.1007/s11295-018-1235-3
SN - 1614-2942
SN - 1614-2950
VL - 14
IS - 2
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Miesner, Timon
A1 - Herzschuh, Ulrike
A1 - Pestryakova, Luidmila Agafyevna
A1 - Wieczorek, Mareike
A1 - Zakharov, Evgenii S.
A1 - Kolmogorov, Alexei I.
A1 - Davydova, Paraskovya V.
A1 - Kruse, Stefan
T1 - Forest structure and individual tree inventories of northeastern Siberia along climatic gradients
JF - Earth system science data : ESSD
N2 - 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.
Y1 - 2022
U6 - https://doi.org/10.5194/essd-14-5695-2022
SN - 1866-3508
SN - 1866-3516
VL - 14
IS - 12
SP - 5695
EP - 5716
PB - Copernicus
CY - Göttingen
ER -
TY - JOUR
A1 - Wieczorek, Mareike
A1 - Kolmogorov, Alexei
A1 - Kruse, Stefan
A1 - Jacobsen, Inga
A1 - Nitze, Ingmar
A1 - Nikolaev, Anatoly N.
A1 - Heinrich, Ingo
A1 - Pestryakova, Luidmila Agafyevna
A1 - Herzschuh, Ulrike
T1 - Disturbance-effects on treeline larch-stands in the lower Kolyma River area (NE Siberia)
JF - Silva Fennica : a quarterly journal for forest science
N2 - Tree stands in the boreal treeline ecotone are, in addition to climate change, impacted by disturbances such as fire, water-related disturbances and logging. We aim to understand how these disturbances affect growth, age structure, and spatial patterns of larch stands in the north-eastern Siberian treeline ecotone (lower Kolyma River region), an insufficiently researched region. Stand structure of Larix cajanderi Mayr was studied at seven sites impacted by disturbances. Maximum tree age ranged from 44 to 300 years. Young to medium-aged stands had, independent of disturbance type, the highest stand densities with over 4000 larch trees per ha. These sites also had the highest growth rates for tree height and stem diameter. Overall lowest stand densities were found in a polygonal field at the northern end of the study area, with larches growing in distinct " tree islands". At all sites, saplings are significantly clustered. Differences in fire severity led to contrasting stand structures with respect to tree, recruit, and overall stand densities. While a low severity fire resulted in low-density stands with high proportions of small and young larches, high severity fires resulted in high-density stands with high proportions of big trees. At waterdisturbed sites, stand structure varied between waterlogged and drained sites and latitude. These mixed effects of climate and disturbance make it difficult to predict future stand characteristics and the treeline position.
KW - treeline
KW - Larix cajanderi
KW - Siberia
KW - fire
KW - stand structure
Y1 - 2017
U6 - https://doi.org/10.14214/sf.1666
SN - 0037-5330
SN - 2242-4075
VL - 51
IS - 3
PB - The Finnish Society of Forest Science
CY - Helsinki
ER -