River Flooding As a Driver of Polygon Dynamics: Modern Vegetation Data

Open Access in Geophysics Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Nonlinear Processes Salix

Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access coverage and , Scorpidium 4 Meesia trique- Open Access Discussions Discussions Discussions Discussions Discussions Discussions Discussions Discussions Discussions Discussions Discussions Discussions Betula ¨

uller Climate in the rim-to-pond Sciences Sciences Dynamics Chemistry of the Past Solid Earth Techniques Geoscientific Methods and and Physics and Atmospheric Atmospheric Atmospheric Data Systems Geoscientific , S. M Earth System Earth System Measurement Scorpidium scorpioides Instrumentation 1 Hydrology and 1 Ocean Science ), indicative of a relatively Annales shrubby Biogeosciences The Cryosphere Natural Hazards Natural Hazards and Earth System and Earth Model Development Geophysicae Larix E, northern Yakutia, Siberia) has Scorpidium scorpioides ◦ , J. Wolter 3 , and F. Tian Andromeda polifolia 1 Navicula vulpina and ¨ ur Polar- und Meeresforschung, 14473 Potsdam, N, 113.921 4068 Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open Access Open 4067 Access Open Access ◦

occurred during periods of harsh climatic condi- Carex spp. and overgrown by epiphytic diatoms such as taxa. This stage coincides temporally with a period Climate , L. A. Pestryakova Sciences Sciences Dynamics Chemistry , L. Schirrmeister of the Past 1,2 Solid Earth Techniques 1 Geoscientific Methods and and Physics and Advances in Atmospheric Atmospheric Atmospheric Data Systems Geoscientific Geosciences Eunotia Earth System Earth System Measurement Instrumentation Hydrology and Ocean Science erent moss association occurred during times of repeated river Biogeosciences The Cryosphere Natural Hazards Natural Hazards ff and EGU Journal Logos (RGB) EGU Journal Logos and Earth System and Earth Meesia triquetra Drepanocladus Model Development ¨ at, Institute of Geological Science, 12249 Berlin, Germany , S. Wetterich , U. Herzschuh and/or 2 1 and a dominance of benthic diatoms (e.g. This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. University of Potsdam, Institute of Earth and Environmental Sciences, 14476Northeast Potsdam-Golm, Federal University, Department for Geography and Biology, 677000 Yakutsk, Freie Universit Alfred-Wegener-Institut Helmholtz-Zentrum f on polygon development and the type of peat accumulated. flooding (indicated by homogeneous medium-grainedduring sand the that annual probably spring accumulated snowtra melt), characterized by an abundancehigh of pH and a high tolerancetion of (inferred disturbance. from A moss comparison and offrom macrofossil the spectra) pollen local with polygon spectra) the vegeta- indicated regionalbecame that vegetation (inferred established the during moss association relativelyation with favourable dominated climatic by conditionstions. while Our the study associ- revealed a strong riverine influence (in addition to climatic influences) a well-established moss associationscorpioides dominated by submerged orTabellaria floating flocculosa in which the polygon wasmixed only grain drained sizes. by A lateral di subsurface water flow, as indicated by on the polygon rim, atransition dominance zone, of and awithin predominantly the monospecific pond. Thesils, TOC content, moss TOC/TN remains, ratio, diatoms, grain-size,a vascular and sediment plant core pollen macrofos- from were athe transect analysed across formation for the of polygon. two the Radiocarbon verticalpond polygon dating and sections started indicates that rim at and least haveidentified, 1500 not indicating yr changed two ago; contrasting since the development general that stages positions time. of of the Two the types polygon. The of first pond was vegetation were The spatial and temporal variabilityarea of of a the low-centred lower polygonbeen Anabar on investigated River the using (72.070 eastern a floodplain multi-methodsquare approach. metre The present-day was vegetation analysed in revealing each a community of Abstract Biogeosciences Discuss., 10, 4067–4125, 2013 www.biogeosciences-discuss.net/10/4067/2013/ doi:10.5194/bgd-10-4067-2013 © Author(s) 2013. CC Attribution 3.0 License. River flooding as a driverdynamics: of modern polygon vegetation data and a millennial peat record fromRiver the lowlands Anabar (Arctic Siberia) R. Zibulski Received: 31 January 2013 – Accepted: 12Correspondence February to: 2013 R. – Zibulski Published: ([email protected]) 1 MarchPublished 2013 by Copernicus Publications on behalf of the European Geosciences Union. N. Schilling Germany 2 Germany 3 Russia 4 1 5 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | C ◦ E: Rivas-Martinez and Rivas-Saenz, ◦ 4070 4069 N, 114.083 ◦ exchange have been done, e.g. in low-centred polygons on Samoylov 2 C) and only a thin snow cover. Summers are dominated by Icelandic and Aleu- ◦ The study area is underlain by 500 to 600 m of permafrost (Yershov et al., 1991). In the North Siberian Lowland, polygon mires are particularly common along rivers Climate and the nature of the soil substrate are the main factors influencing the for- 36.1 Demek, 1970). The study area is characterized by meander terraces, thermokarst lakes the Siberian landmass− resulting intian low lows; temperatures they (mean(Saskylakh are Climate January short Station, temperature: and 71.967 2007). relatively cool, with mean July temperaturesTemperature of increases 12 at thecesses that beginning led of to the permafrost Holocene degradation and initiated widespread thermokarst subsidence pro- (Czudek and 2 Geographic setting The study areacontinental in climate. north-western Winters Yakutia are (Siberia) dominated is by characterized a by stable an high pressure extreme system over or in the(designated vicinity 07-SA-LY) of on the lakes.ing flood We a plain therefore multi-method of selected approach thepollen, that lower an diatoms, Anabar included grain-size, individual River analysis and low-centred as organic ofobjectives study polygon matter, of vegetation, together site fossil this with us- moss research radiocarbonrelation tissue, were dating. to (1) The abiotic to factors investigateabiotic environments, the (2) and spatial to (3) pattern to reconstruct identify of past the vegetation drivers changes in behind in the polygon biotic dynamics. communities and Island (Runkle et al., 2013). Othershort-term investigations changes have in used vegetation polygon (De sediments Klerkscape to et dynamics trace al., (Minke 2011) et and al., long-term 2009;have changes Zoltai in and identified land- Vitt, the 1990, 1995). general While processespolygon previous studies dynamics that and lead associated to driving the factors formation remain of only poorly polygon understood. mires, the ecosystem CO ies with a special focus on the carbon content (Zubrzycki et al., 2013) and the net et al., 2007). Investigations haveonal previously been landscapes conducted and into the thethe ecology active way of layer in polyg- has whichet been al., they investigated 2006; function. in Yoshikawa and For Hinzman, relationprocesses 2003) example, to and (Mackay, 2000). the the the displacement The form hydrology of dependence ofpolygonal soil of of by the tundra frostheave the polygon on energy (Riordan precipitation andgated water and (Boike balances et weather al., in conditions 2008). the is have Especially also in already located the been Lena inbeen investi- River an investigated Delta (Samoylov (Boike area Island) et of which al., river 2012; influence Fiedler form et and al., sediment 2004). characteristics In have the last decade stud- in the arctic tundra1997). is therefore fixed in peat from decomposedmation bryophytes of (Longton, polygons while their dimension,trolled form by and complex position positive within feedbacks landscapes between are vegetation, con- ice, water, and peat (Minke (the polygon pond). Sincecycle these polygons (Hobbie have et an al.,3 important % 2002); role of although in the the the(Post arctic mires arctic et al., carbon of land 1982). the Improving area, ourscientific arctic understanding they objective of tundra contain polygon Due only dynamics more to is covercommon therefore than the about as a harsh 15 key well % living as ofare conditions those consequently the plants capable replaced with of world’s at asexual short soil higherrequirements reproduction. latitudes life carbon for Woody by cycles light, cryptogams, shrubs are temperature as and and a herbs nutrients result of (Frahm, 2001). their lower Most of the biomass Polygon mires are the mostadvanced common stage type of of arctic succession, mire.Low-centred Often known polygons these as mires evolve low-centred occur whenrims) in polygons above an frost-heave (Minke ice processes et wedges and al., form depressions 2007). ridges between the (the ridges that polygon are often water-filled 1 Introduction 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Be- Alectoria together with C. ◦ (data from Saskylakh station; Huh and 1 Cetraria cucullata − s 3 4072 4071 ) and tundra bog” vegetation type according to the E; Fig. 1c, d) was selected for detailed study. The polygon was ), dwarf shrub tundra ( ◦ N and 113.921 ◦ trees up to 4 m high. The area belongs to the geobotanical sub-province “Anabar- We also collected pH and conductivity measurements in the field for both soil and Our field vegetation survey has indicated that the study site lies within an area with The lower part the Anabar River in particular is a meandering and partly braided river Polygon fields in the Anabar River lowlands were observed from helicopter flights 400 km west of the Lena River Delta and has a discharge that is highly variable, by radiocarbon acceleratorRadiometric mass Dating spectrometry and (AMS) Stable Isotope at Research the in Leibniz Kiel (Table Laboratory 1), for using a Tandetron for the 27 cm corecal length soil and sections not for of theand 42 cm original G3, respectively, length 54 at cm (Section 2.3 length. cm A)Wegener resolution. We and Institute The also in 50 materials sampled cm Potsdam, were verti- length Germany transported and (Section to the stored B) Alfred at in 4 3.2 plots G1 Radiocarbon dating Handpicked, alkali-residue plant remains from twelve sediment samples were dated surface water along Transectment. G We (Fig. obtained 2a) a usingG8 short a (pond) WTW core using Multi (Core27 a cm 350i C) simple in measuring of the plastic instru- therial. plastic tube upper Sub-samples tube 54 were (Fig. cm taken during 2a). ofa from the Core sediment The homogenous coring C from compression core at process plot over became 1 cm due the compressed intervals whole to Since to length the we of cannot loose the assume organic core, mate- we present the data divided into 156 square meterWe plots, measured using the a elevation of gridto the labelled land A the surface to (including water L the and levelof floor 1 in each of to the the plot 13 pond) m (method pond relative (Fig.plants according as 2). was to recorded well Donner, for as 2007). eachBlanquet the The plot in floristic coverage depth modified of approach. of per the cent Severallevel the main because classes taxa active vascular the according could layer, flowering to period the at only Braun- of the be most centre taxa recorded was to already over. genus or family 3.1 Fieldwork Fieldwork was completed in72.070 August 2007. A typical low-centred polygon (07-SA-LY; 3 Materials and methods to the polygon field that is both seasonally andLarix inter-annually variable. Lena subarctic” (Isaevtula et exilis, al., Salix pulchra 2010)ochroleuca, with Coelocaulon a divergens “widelyagriculture spaced map from dwarf Yakutia (Matveev, shrub 1989). tundra ( system (Fig. 1b). Thesmall polygon streams field flowing in intoThus which the the our Anabar rapid melting site River of in iscombined snow summer with located in the but spring is vicinity as can drained of result the be by of site flooded the several to sharp in the increase large spring. in Anabar River temperature results in a water supply Saskylakh on the North SiberianThe Lowland Anabar in River the is north-eastern fed partwhich by of originate the Yakutia (Fig. Bol’shaya on Kuonamka 1b). the and Anabar∼ the Shield. Malaya It Kuonamka rivers, drains intoboth the western seasonally part and of theRiver annually. Laptev freezes In Sea to contrast thespring bottom to that during rivers reaches winter a in followed maximumEdmond, by southern of 1999). a 5000 Yakutia, m rapid the increase in Anabar discharge in ganicrich and are classified as Histic Fluvisols (Jones etto al., 2010). be restrictedwithin to a areas polygon along fieldriver the on bank and flanks the within Anabar of the River curve rivers. of floodplain The an about abandoned studied 800 meander. m polygon It to lies is about the located 15 east km north of of the alas depressions, and polygon mires. The uppermost parts of the soils are wet and or- 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | magnifica- × ) to determine 2 r COOH for 12 h) and 3 , and 400 × C values are expressed 13 δ , 100 ¨ as (2008) from the Bryophyte × ). Amblystegiaceae taxa were cient of determination ( 0.2‰. The ffi ± 4074 4073 for a maximum of 4 weeks) subsamples from Sec- C) in TOC were measured with a Finnigan DELTA 2 http://www.mobot.org 13 O δ 2 , ‰) relative to the Vienna Pee Dee Belemnite (VPDB) 850 and 850–250 µm fractions was again analysed using δ + erentiated in detail in Section B. ff raction particle sizer (Beckmann-Coulter LS 200). Grain-size fractions are given in Vascular plant macrofossils were extracted from all depths in sections A and B by An end-member modelling algorithm was used to calculate robust end-members Stable carbon isotope ratios ( Grain-size distribution analyses (for grain sizes between 0.375 and 1000 µm) were ff Pollen identifications were based1991) on the and relevant on literature (Beug, a 2004; regional Moore type et slide al., collection of pollen types. The total pollen from ence collection at AWI Potsdam. 3.5 Pollen analysis Pollen analyses were performed onsamples all in 27 the samples from(50 laboratory %; Core included C. 2 h Processing treatment of boiling),mounting with pollen followed in HCl by glycerine. (10 %), acetolysis,cept At three KOH sieving least samples (10 (7 (from %) µm) 350 20 and in terrestrial to 17 HF an pollen cm) which ultrasonic grains had bath, were extremely low and counted pollen concentrations. in all ex- washing 25 mL subsamplesmosses. through Material sieves in withZEISS the the light and same stereo meshthe microscopes help sizes of (AxioLab as vegetation 40, atlasesjerinck, used Stemi and 1947; for seed 2000-C) Berggren, identification and 1969, manuals 1981; identified (Anderberg, Katz with 1994; et Bei- al., 1965) together with a regional refer- not di mesh sizes. Moss remainsstereo larger microscopes (AxioLab than 40, 850 Stemi µmtion; 2000-C) were vascular with plants analysed 25 were separated using fromportions. ZEISS mosses The in light identification order and to of evaluate mosses theirFrey, 2004; was relative Lobin based pro- et on al., the 1995)Flora relevant and literature of (Frahm descriptions and of North Heden America website ( Moss remains were analysed forof every sieving second sample residue from afterupper Core the C and (available KOH the volume washing lowersamples step samples from for Section from pollen B Section preparation: (50 A mL). 5–12 The mL), (50 mL), material the and was 15 washed through irregularly 250 distributed and 850 µm 3.4 Analyses of moss remains and vascular plant macrofossils volume per cent (vol %). (EMs) from the7.14.0.739), total using set conceptual of modifications proposednumber grain-size by of distributions Weltje potential (1997). EMs with The isWe MATLAB minimum thereby used software represented the maximum by (R2012a; value the ofthe cumulative the explained maximum mean variance. coe feasible numbermember) of were determined EMs. with The a test final for EMs robustness (Dietze (robust et EMs al., and 2012). the residual standard. conducted on freeze-dried carbonate-freeorganic-free (treated (treated with with 10 3 % % CH H tion A, Section Bdi (excluding the sample from 9.2 to 6.9 cm) and Core C using a laser Total carbon (TC), totalmeasured organic using carbon an elemental (TOC) analyzer andmeasured (Elementar total Vario on EL nitrogen carbonate-free III). (TN) The samplesresults TOC contents are (treated content given were was with as weight 4 % per cent HCl). (wt The %) and TC,S the TOC mass C/N and ratio spectrometer is TN coupledmix expressed to as system. TOC/TN. a The FLASH analysesin element were delta analyser accurate to and per a mil CONFLO notation III ( gas “CALIB rev 5.01” software modified withused the to IntCal04 calculate dataset the (Reimer calibrated et ages. al., 2004) was 3.3 Geochemical, stable carbon isotope, and granulometric analyses 4130 AMS system (High Voltage Engineering) with a single caesium sputter ion source. 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | . 2 ® O 2 Sor- , and Botryococcus, , 13 m (Fig. 2b). The × Pediastrum . The following literature was Achnanthes, Fragilaria, Nav- in G1) and lowest in the pond × 1 − erences in plant taxa between the ff 4076 4075 0.81). Along Transect G, the pH was found to be = 2 r in G8). 1 − genera (Krammer, 2000, 2002, 2003; Lange-Bertalot, 2001). 7 m. The ground surface measurements indicated that the polygon × Cymbella ) were counted from the pollen slides and their abundances expressed relative vegetation pattern and A vegetation survey over the grid revealed di analysis which yielded a stressvation value and of active 16 % layer (Fig. depth A1). and Axis arrange 1 the correlates polygon well vegetation with along ele- a rim-to-pond the polygon’s pond (Fig. 2c). Thisatively depth consistent varies beneath considerably the beneath the waterbodywell rims (Fig. with but 2c). is the In rel- active general, layerabout the depth 6.14 elevation in ( correlated the rim,conductivity 5.70 in was the highest rim-to-pond on transition zone,water the and (e.g. rims 6.25 16 (up µS in cm the to pond. 84 The µS cm rim, the rim-to-pond transition zone, and the pond (Fig. 3), as is clear from the NMDS the pond in contrastto to a transects sunken H crack to inpond. K Transect The L (plots maximum that 5 height has towithin of a 10), these the depth which other rims of cover 62 rims were a cmThe was detected below transition active 35 e.g. the layer zone cm, depth water from and ranges level D11 only from in to minor 21 the cm depressions G11 beneath and the from rims to K2 73 to cm below K11 the (Fig. floor 2b). of 4.1 High-resolution spatial characteristics of the investigated polygon and its The 07-SA-LY low-centred polygon hasouter dimensions margin of of the about investigatedarated 12 polygon from approximately its traces neighbouring polygons. the The3–4 ice-cracks m. distance that The from sep- polygon the centre crack is todimensions filled the of by rim an 5 margin intrapolygonal is pondis of water not with hydrologically approximate closed. Transects A to C are up to 44 cm above the water level in NMDS plots 4 Results package, Oksanen et al., 2007). Various supplementary parameters were added to the (NMDS) analysis of speciesplemented percentages in using R the version Bray-Curtis 2.15.0 dissimilarity (R index Project im- for Statistical Computing, using the “vegan” Komarenko and Vasilyeva (1975) “The diatomsdiatoms of the of USSR” Russia” (1974, 1988, (2003),used 1992), in and “The this Loseva paper (2000).icula is The based on classification the of latest diatom revisions of species the 3.7 Statistical analysis Statistical analyses were performedthe to diatom assemblages deduce of patterns Core C. in We surface applied vegetation a non-metric and multidimensional in scaling were analysed using aferential interference ZEISS contrast light at a microscopeused magnification (AxioScope.A1) for of the equipped 1000 determination of with diatomBertalot a taxa: (1993), Krammer dif- Lange-Bertalot and Lange-Bertalot and (1986), MetzeltinLange-Bertalot Lange- (1996), and Lange-Bertalot et Genkal al. (1999). (1996), The and following regional works were also consulted: 3.6 Diatom analysis About 0.5 g of each sampleof from diatoms Core C was was usedous conducted for in and diatom analysis. accordance organic The processing to components(30 %). Pestryakova were Cleaned et diatom removed al. samples byAbout were (2012): heating 500 mounted the on with diatom calcare- microscope HCl valves slides were (10 with %) counted Naphrax and per H slide along random transects. Samples pollen spectrum isaddition, taken common as non-pollen 100 %Delitschia, palynomorphs for Gelasinospora, Geumannomyces, (NPPs, the Glomus, Macrobiotus e.g. calculation hufelandi dariales of the pollento percentages. the total In terrestrial pollen. arboreal and terrestrial non-arboreal taxa (excluding Cyperaceae) identified in each 5 5 20 25 15 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | – 6 erent erent ,P 0.21), ff ff 95 ± –P 5 Andromeda 0.89 Dryas punc- ,P = C values range erent sedimen- 2 96 ff r 13 δ –P 270 µm). Consider- 4 25.3 ‰ in Section B er markedly between ∼ − ff trees (with a maximum 29.8 and sp. appear in a small depression − 0.19), and Core C ( ± Larix gmelinii 0.85 sp., with abundances between 5 and 80 %. Pedicularis = 4078 4077 2 r sp. Eight ; only in the shallowest parts is it intermixed with Vaccinium (which is abundant over 2/3 of the grid), the two di and Vaccinium 25.9 ‰ in Core C. The ratio ranges di − Salix 26.3 ‰ in Section A between and 0.14), Section B ( − ± Betula nana 0.92 30.6 and species (Type A with maximum abundances of 20 to 40 %, and Type B − = . Relatively dry zones situated only few centimetres above the water level Scorpidium scorpioides ) and EMs ranging from 3 to 6 in order to extract final robust EMs and the 2 29.0 and r 93 − Salix –P Carex taxa In addition, individual plants of 7 0.1 %) reliable TOC/TN values are not available for the lower parts of sections < ,P The grain-size composition of the polygon sediments is dominated by the fine to 94 Section A ( for the robust end-memberC model. (0.88) The and median Section ofAll A profiles EM1 (0.75) show scores are obvious for higher variationsFig. the in than A2 the whole the for EM1 sections of median to A score Core tion and residual for B). zone) ratio Based Section and (Fig. on Core 4 B this for Capproximately (0.58). information, Core similar (pond) Section C, period can B and of be (rim-to-pond time. transi- correlated,tation In indicating pattern contrast, that and Section both cannot A be records shows correlated cover a with an di Section B, or with Core C. remaining noise) were finally identified.together They with are presented their in rangeEM1 the represents of loading 75.3 plot confidence % (Fig. of asto 5) the calculated a total medium from variance to 16 withining the coarse the end-member goodness original sand models. of data fraction variable and and (180–720 sample µm, corresponds fit, peaking we at found a reasonably good modelling for medium sand fraction (Fig. 4,as Fig. abundant A2). as Only sand. insitional The the data uppermost inversion suggests parts algorithm themations is for to silt minimum end-member about be number modelling twice 3 of ofweight or transformations compo- EMs 4, in considering and the the allP models maximum weight (with number transfor- percentile to rangesresidual be of member. 6. P One We robust therefore EM used (EM1) di and a residual member (RM; describing the i.e. A and B. The TOC/TNbetween ratios in Core C varyand between between 7 and 26. The the profiles, and also vary within each profile (Fig. 4, Fig. A2). A and B; 26 wt. % in Core C). Due to the low TN contents (below the detection limit, low in the lower parts ofCore the C) profiles and (0.3 higher to in 1.3 the wt. uppermost % (most in recent) sections samples A (32 and B; to 1 33 to wt. % 4 in wt. % sections in relationship; at least thegeochronological near record. surface date (from 3.5 cm depth) is4.3 the youngest of General the properties of the sedimentaryThe fill two sections (AG8, and respectively, were B) analysed and for their theposition TOC sediment (Fig. content, A2 TN core content, for (Core sections and A C), grain-size com- and from B, plots Fig. 4 G1, for G3, Core and C). The TOC values are relatively 4.2 Geochronology and age-depth relationships The oldest agescal were AD) obtained and from Section theCore B bottom C (417–568 samples range cal from AD) between (Table Section 1213 1). A and The (420–539 1635 calibrated ages cal obtained AD, for but do not show a clear age-depth height of 4 m) were(the recorded central from part the of upper the rimand/or NMDS sites. biplot) is The characterized rim-to-pond by transition theare zone appearance covered of by Type B The pond vegetation (on theof right the side of moss the NMDSCarex biplot) consists almost exclusively between the pond and the crack on Transect L. is highly variable and diverse,ubiquitous but shrub is always dominatedshrubby by vascular plants suchwith as a the mean coveragetata, of Ledum approximately palustre 20 % in non-aqueous habitats), transect. The composition of the rim vegetation (appearing on the left side of the biplot) 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | (11) 2 %). -type -type (from 14 %), leaves Bryum (4) and ∼ ( ∼ ( Dicranum sp. Navicula Fragilaria 13 %) dominates , while subdomi- Betula nana Bryum pseudotri- ∼ 0.2 %). In contrast, Alnus fruticosa (7), 10 %) and < Calliergon < Dryas punctata ( -type remains quite sta- (5 %), -type, erent from the spectra in ; Fig. A5) and Section B ff ; each and 3 − Scorpidium scorpioides Campylium stellatum ) and occurred only in trace quanti- 3 − Hylocomium splendens . Gomphonema Betula nana was recorded (not included in Fig. 6). A. turgidum Alnus fruticosa 15 %), Scorpidium scorpioides (7 %), and Navicula vulpina, Hantzschia amphioxys, ∼ and ( 4080 4079 and 3 % over the whole core). Most samples were (8 species), > ). Section A contains a relatively large concen- 3 Hamatocaulis vernicosus 0.16) and at 14.5 cm (0.11) core length, and also in − Geumannomyces ∼ Hamatocaulis vernicosus leaves (2.2 leavescm pollen occurs in low but stable abundances. Except at Rhizomnium pseudopunctatum and Cymbella dominate the identifiable vascular plant macrofossil spec- spp., was only present in small quantities ( Aulacomnium turgidum Larix ; Fig. A6) while the lower part of Section B is dominated Rhizomnium pseudopunctatum (11), 3 Meesia triquetra agg. (20 %), (9.5 %), − Aulacomnium palustre Distichium capillaceum and Hamatocaulis vernicosus occurred in most samples from Section B and Core C, but its abun- ). No identifiable macrofossils were found in Core C, but this may have 3 Botryococcus (with 10 %). − Larix gmelinii Pinnularia < 8 %), Aulacomnium (4) (Fig. 8). Most genera (63 % of the total) were represented by only one or ( Drepanocladus seeds (0.1–1.1 seedcm Andromeda polifolia ∼ ( (11) Carex Well-preserved diatom valves were found in all samples from Core C: 104 species Pollen analyses were performed on Core C. In total, 39 pollen taxa and 26 non- The relative proportion of total vascular plant to moss remains (the VPM ratio) was Needles of the 32 species thatdominated met by our either criteria ( benthic diatoms (e.g. dances than the terrestrial plants.palynomorphs We found relatively high quantities of the non-pollen were identified belonging to 35Eunotia genera. The most important generaStauroneis were two species, which is aMost regional of characteristic the of diatom diatom species communities were in arctic rare: waters. thus, for the statistical analyses we only used pollen palynomorphs were identifiedand Poaceae (Fig. are 7). the mostble abundant throughout pollen the taxa. core,show while opposing the trends. abundances18.5 of cm core Poaceae length and the Cyperaceae (excluded from the pollen sum) have higher abun- ratio is relatively high atthe 24.5 cm uppermost ( samples (e.g. at 2.5Section cm, B: where high it moss is 0.98). contentsat A were similar 35.7 determined cm pattern for was depth) most found of and for with the a mosses lower maximum dominate horizons VPM in (except ratiodominant of most (VPM 0.8 samples ratio at from 0.3) 10.4 cm in above and theVPM 24.2 8.1 uppermost cm ratios cm part depth, depth. for of Mosses the Section are0.17, B lowermost particularly (above respectively. and 1.2 cm uppermost depth). samples The from Section A were 0.12 and (2.4 leavescm been due to the small quantity of sediment analysed. examined for all samples(Fig. from 6). Section Most A of the (Fig. samples A4), from Section Core B C (Fig. were A3) dominated and by Core mosses, C but the VPM tration of The genus Aulacomnium the moss spectrum inCampylium the stellatum uppermost sampleacutifolium from Section A, which consists also of tra in the(5.7–19.0 upper needlescm parts ofby Section A (0.1–6.2 needlescm (1.2 cm) and lowermost (40.3Section cm) B samples, is and completely CoreA di was C. composed The of mossTomentypnum community nitens in thequetrum lowermost sample from Section ties. Only a single leafThe of vertical distribution pattern oflar the to main that moss in taxa CoreMeesia in C, which triquetra Section supports B (Fig. the A3) correlationdance inferred was is highly from simi- variable. the The grain-size upper record. and parts of Core Section C B (except are for10.5 dominated the uppermost by, to 3.5 or cm) 0 cm entirely composed infrom of, the Core rim, C i.e. and from Section from A 25 (Fig. to A4), which 0 cm was only depth determined in in the Section uppermost B). The moss spectrum We identified 12 moss taxaMost in Core abundant C were withinnant the identifiable were moss leaf fractionpseudotriquetrum (Fig. 6). 4.4 Bioindicators 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | and erent Euno- ff Hama- is present Meesia tri- Stephanodis- Botryococcus , genus , . Subunit 1.3 is ). Furthermore, Scorpidium Amblystegiaceae content in Section type pollen. Drepanocladus cossonii -type pollen is abundant. Achnanthidium minutissi- , Meesia triquetra Scorpidium was found at 7 cm length. The Meesia triquetra Alnus fruticosa Aulacoseira subarctica Gomphonema lagerheimii Alnus fruticosa , and the 4082 4081 Tabellaria flocculosa genus. Subunit 1.2 contains a large proportion of erent types of polygon pond sediment ) were only dominant at 21.5 and 20.5 cm length in ff Scorpidium scorpioides, Meesia triquetra, Hamatocaulis Botryococcus taxa (Figs. 8, 9). Stephanodiscus minutulus (95–100 %) in Core C, but the (40 %), but low abundances of ), while planktonic taxa ( species dominate the moss spectrum. In contrast, (25–50 %) as well as abundant planktonic diatoms; it also has a low Drepanocladus Eunotia ) or epiphytic diatoms (e.g. Cyclotella ocellata erent diatom spectra. Most epiphytic taxa were located in the lower left Scorpidium , ff , the green algae is only found in small quantities. Furthermore, Unit 1 is characterized by a dom- Drepanocladus Navicula vulpina, Stauroneis phoenicenteron, Sellaphora pupula , and several Unit 2 (Subunit 2.1: Core C 24–14 cm length and Section B 43.7–27.6 cm depth Unit 1 (Subunit 1.1: Core C, 27–24 cm core length and Section B 50.6–43.7 cm depth elevation (Fig. 2a), i.e.thaw depths shallow below thaw the depths pond. beneath It is the assumed elevated that rims the and thick moss greater layer and the tall, dry Cyperaceae content and generally acontent very shows low a pollen major concentration. peak The in Subunit 2.2. 5 Discussion 5.1 Small-scale spatial structure of polygons We found a strong correlation between thaw depth beneath the polygon and its surface (e.g. Poaceae are well representedabundant in in some the sections of pollen Unit2.1 spectra. 2. and Despite In 2.2 of addition, these have common some Ranunculaceaetocaulis characteristics specific vernicosus subunits are characteristics. Subunit 2.1 contains abundant dominated by B is rather low (rangingwere from more 86 % abundant. at 8 cm, to 4 % 1.2 cm)Subunit while other 2.2: Core Cized by 9–3 cm high length scoressand. and for The EM1, Section TOC indicating B valuesin and a 16.1–9.2 most cm TOC/TN dominance samples ratio depth) and of often are is well-sorted abundant. mostly Most character- medium low. samples grained are dominated by benthic diatoms cific characteristics that occuris in both abundant Core in Cnon-determined the and mosses Section samples (approximately B. from 45 %also Subunit of belong 1.1. the to total They moos the Scorpidium also remains), scorpioides which contain could large quantities of Despite of these common features, each subunit (1.1, 1.2, and 1.3) has some spe- inance of epiphytic diatomsmum such as vernicosus Subunit 1.2: Core C 14–91.3: cm Core core C length 3–0 cm and corescores Section length for B, and the Section 27.6–16.1 cm B residual depth. 9.2–0 memberthe cm Subunit depth) (RM) TOC is indicating content characterized a and by high some mixture the of TOC/TN grain-size ratio fractions. are Both quetra quite high in these units. composition. We defined the boundarydiatom between these NMDS units analysis (Fig. 4) (Fig.pollen on taxa, 9). the non-pollen basis Meaningful palynomorphs) of sediment the werevious superimposed parameters relationship on (EMs, exists the between moss NMDSrameters, indicating diatom plot. taxa, that An assemblages the ob- and diatomto spectra these the are superimposed related relative to abundances pa- the of end-member scores and completely di part of the plot and most benthic taxa4.5 in the upper right Characterization part. of two di Two sedimentary units thatrim-to-pond were transition only zone found (Sectionious in B) parameters the can described polygon be centre distinguished above, on (Core while the C) the basis and rim of the section the var- (Section A) has a di tia, Tabellaria flocculosa cus minutulus Core C. A secondNMDS peak analysis in (NMDS plotcore in lengths of Fig. 21.5 9) and yielded 20.5 cm a were stress excluded value from of the 17 NMDS %. analysis Samples due from to their Sellaphora pupula 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | similar to 3600 yr cal spp. present ∼ ect that is even ff community seems Carex spp., and Ericaceae Drepanocladus revol- , ; de Klerk, 2008). . In contrast to our study, Salix , sp. In these zones, sites with Andromeda polifolia Carex sp.). The low resolution of environ- erent vegetation types corresponding ff Betula nana 1200 yr cal BP for the Indigirka Lowland Comarum palustre erent sites for when polygon mires first , ∼ ff Scorpidium scorpioides type B, and sp., (2) a dwarf-shrub and herb layer com- Dicranum Andromeda polifolia 4084 4083 sp., and Ericaceae and (3) a moss layer with that dominates (80–100 %) vegetation within the ect from thaw water (Woo and Guan, 2006). We Salix ff and , sp. and as common elements of vegetation in the rim-to-pond Larix gmelinii Vaccinium Carex ¨ ofle et al., 2013; Matveyeva, 1994; Minke et al., 2009). Pedicularis and Betula nana sp., Andromeda polifolia and Vaccinium Polytrichum Scorpidium scorpioides Polygonum Sphagnum squarrosum Ledum palustre and erent ages have been inferred from di The water depth, and thus the position of the pond margin, depend on the water The hydrological conditions in the rim-to-pond transition zone vary markedly dur- The polygon is located in the Anabar–Lena subarctic zone (Isaev et al., 2010), with The vegetation on the rim contains taxa that prefer dry soils or at least avoid per- ff ¨ ager, 2005) such as Western Siberian parts ofBP the in Arctic. Canada Other (Fortier estimates and have Allard, ranged 2004) from to to represent a characteristicscribed and by widespread Liebner vegetation et type al.Siberian as (2011) polygons in and it by polygons has Nebel of also and the been Philippi Lena-Delta, (2000) de- Donner in5.2 et mires al. of (2007) central Age–depth in Europe. relationships Di appeared in periglacial landscapes,(1995) sometime estimated during ages of the 2000 late to Holocene. 3000 yr Botch for et various al. mire zones in the European and merged moss pond belongs to the Amblystegiaceae family whichand can in assimilate under low a light thinextend conditions ice cover the (Frahm, 2001). short That growinggrowing special season conditions characteristic and in enables means arctic them that polygons. to they The are well-adapted to the harsh transition zone (in addition to supply (e.g. from rainfall) and thevestigations took evapotranspiration during place in summer. Since mid-August towards ourthat the field the end in- of water the level arctic (17and summer cm we that at assume the the pond deepest2012). at site) The that was transitional time the vegetation lowest varies representedin with of an the the the area shallow water summer parts of depth season permanent of with the water pond (Boike (as et also al., reported by Tyler, 1981) The commonly sub- the rim vegetation but containing atolerance higher or proportion of occur plants commonly thatMinke have in et a raised greater al. water bogs (2009) and suchthe northern Donner as Indigirka (2007) Lowland carried and outvens identified comparable vegetation analyses in dwarf-shrub canopy of ing the short growing season (Økland, 1990). The assemblage comprises a low and shrub layer composedsuch of as posed of xerophilous mosses ( mental parameter measurement doesfor not the allow microhabitats identification on of thecular rim. structural plants However parameters previous and investigations bryophytes have trace shown small-scaleddepth that patterns or vas- related pH to (Ellis the and water Rochefort, table, thaw 2004; Vitt, 1995; Walker et al., 2011). logical microhabitats. We distinguished threeto di the dry polygon rim, the rim-to-pond transition zone,manent and the water water-filled pond. saturationWe (H observed three layers in the vegetation community of the polygon rim: (1) a tree mires in arctic peatlands (Vanderpuye et al., 2002; Vitt, 1995;low Wetterich summer et temperatures al., 2008). andcovering a the short investigated growing 07-SA-LYcal polygon season. elements (Fig. The of present-day 3) theJ vegetation is arctic and therefore boreal dominatedwater-saturated floral soils by are zone typi- dominated by (Abaimov, polygonal 2010;typically tundra or Isaev show polygonal et a forest-tundra that al., well-developed microstructure 2010; of vegetation types tracing the hydro- temperatures (Blok et al., 2010;depth Luthin below and the Guymon, pond 1974). results Inenhanced from contrast, the by the high the large heat positive thaw capacity feedbackobserved of e water a an e relatively homogenouswater distribution across of the neutral polygon to which slightly is acidic in pH agreement in with the other studies on brown moss vegetation on the polygon rims insulate the permafrost layer from the atmospheric 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1 − to be an (benthic di- to represent Alnus Eunotia praerupta, Tabellaria flocculosa er in their main sources ff (which is abundant in Unit Navicula vulpina (Section A) and 0.31 mm yr 1 − ) were also identified in our polygon Scorpidium scorpioides ¨ uller et al., 2010). Two pollen taxa may and 4086 4085 erent extents to our reconstruction of polygon ff Scorpidium scorpioides Meesia triquetra n Island, and by Komarenko and Vasilyeva (1975), Pestryakova ffi was found to have increased in Unit 2. depending on the local humidity. The age–depth relationship is thus 1 − yr 2 − Navicula vulpina We interpret the mosses Diatoms are abundant in arctic freshwater systems. We observed the most marked The general pollen composition is comparable to that of other late Holocene records jacent rim-to-pond transition zone. (2008), and Palagushkina etTabellaria flocculosa, Achnanthidium al. minutissimum (2012)and, in as northern in Yakutia these (e.g. epiphytic other taxa. studies, A our previous shallow studyindicates revealed waterbody relatively that was stable the dominated environmental diatom conditions, by species atom while benthic species) prefers and unstable slightly alkalineof and oligotrophic phases. The proportion changing environmental dynamics in the water-logged polygon depression and the ad- changes in the diatomstudies record from with Yakutia (e.g. respect Pestryakova to etmopolitan al., habitat 2012), taxa, preference. the As with spectra reported are minorcommon dominated in species contributions by found other by cos- of Patrick arcto-alpine andsouthern Reimer and part (1966) in boreal of Alaska, forms. Ba by Moore The (1975) in most the indicator of more temperate conditionsEurope (according and to Klemm Salonen et etportion al., al., of 2011 2013, the for for pollen northern from Siberian supply the to lowlands) wider the We surroundings. polygon The assumeetation pollen originates that signal changes from a thus rather more reflects large than distant extra-localnon-pollen local pro- to polygons palynomorphs regional changes and are veg- within mainly the remainsa studied of local polygon. aquatic signal organisms In (Birks and contrast, and thus the represent Birks, 1980). from northern Siberia (Andreev etpared al., to 2002, lake 2011), but sediments is (Klemmbe very et rich used al., in as 2013; Cyperaceae M climate com- cally proxies. of We tundra consider pollen spectra the (Andreevconditions. percentages et In al., of 2002; contrast, Poaceae Klemm we which et consider al., are high 2013), typi- percentages to indicate of cold thermophilous ments imported by lateral inflow of riverine water or sediments of aeolian origin. of minerogenic material (Weltjewhich and represents Prins, the 2003). fine In tothe coarse our riverine sand transported case fractions sediment the (180–720 fractionthat µm), end Walling rivers probably member and in represents EM1, Moorehead tundra (1989) lowlands150 µm have transport shown (fine sediments sand) with during arecord periods mean may of grainsize indicate normal (diameter) that water of aduring levels. proportion river The high of larger stands the grain characterized minerogenic sizes bythat in input greater the sediment our may RM transportability. have dominated We accumulated by assume the silt fraction has various sources other than riverine sedi- A range of biotic andcontributed non-biotic in sediment various properties ways havedevelopment. been and The investigated to most and di have relevantpond proxies and used rim-to-pond to transition zonemember summarize in scores the polygon summarize development 07-SA-LY are the ofelling shown granulometrical the was in data Fig. applied in 10. to End- a separate meaningful sedimentary way. sections The that mod- di moss, which provides a trapknown for minerogenic to material. be Furthermore,100 rapid arctic gm mosses biomass are producers,rather according uncertain to for Core Frahm C,records which (2001) impossible. makes producing direct comparisons up with other to palaeoclimatic 5.3 Proxy value of the analysed parameters from the rim and rim-to-pond transitioncollected sections. down However, since to our the samples permafrost weresediments table only first we cannot started be to sure accumulate.dicates that The mean this radiocarbon growth is rates dating ranging when of between the 0.27(Section the polygon mm basal yr B). samples These in- high sedimentation rates probably result from the dense bulk of in Yakutia (De Klerk et al., 2011) the latter age being roughly similar to our basal age 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | (Nebel Drepan- Drepan- ) or more Alnus fruti- and Meesia triquetra which is known as indicates stable, slightly Navicula vulpina C record. Our analyses in- 13 δ Scorpidium scorpioides ¨ a and Birks, 2001), which may in Meesia triquetra Hamatocaulis vernicosus Tabellaria flocculosa 4088 4087 ) habitats. Compared to Subunit 1.1, the diatoms in ected by an extreme flooding event (also indicated by an ff pollen), and that the water level remained high for that period ), there is an abundance of which was found by Peterson and Billings (1980) to be characteristic Pinus ect) rather than of biomass productivity. However, a high minerogenic ff Hantzschia amphioxys C values from bulk-organic material show similar general fluctuations to the 13 δ -type. Repeated riverine flooding is indicated by the sandy organic-poor sediments of Sub- We interpret the wt % of bulk organic material to be an indication of the minerogenic The polygon and an increase in the soil-moisture (Sepp water. A sudden changecates that to the a polygon was short-periodinput a of of dominance riverine ofof planktonic time. diatoms A indi- studywith by depths of Moser less etatom than al. community. 5 m, The (2000) planktonic vegetation showed diatomsarea on that never surrounding the in exceeded the polygon 20 Canadian polygon % rimis contained and of and indicating relatively the Finnish in high cold total lakes the proportions conditions di- have uplands of (Andreev been of Poaceae et decreasing which the al., at wider 2002). the Early time, summer resulting temperatures in may reduced evapotranspiration within the diatom record wasa dominated large by ecological amplitude) benthic withaerophilic diatoms preferences ( for (often disturbed ( cosmopolitanSubunit species 2.1 reflect with an increasegon’s in internal the pH pH adjustment (Dam was et repeatedly al., disturbed 1994) by probably fresh because the inputs poly- of sediment and cosa unit 2.1. The high rateage. of sediment Apart supply from probably the ledocladus to floating a exannulatus Amblystegiaceae turnover ( in thea moss pioneer cover- species in young, post-glacialby mires minerogenic (Nebel and sediments. Philippi, 2000)in Furthermore, characterized this the section, greatest an moss additional diversity indication was of observed unstable growing conditions. Similarly, the an indication that favourable growinggushkina conditions must et have al. existed. (2012), Accordingacidic, to the environmental Pala- presence conditions. of Thea lower relatively part low of water level Subunitconditions and 1.1 during the was that upper period characterized part can by by be a inferred relatively from high the pH. Relatively high warm abundances of a particularly long ice-free period for their development (Moser et al., 2000) providing during the earliest recorded phaseblage of is development dominated of the by polygon. epiphytes, The and diatom epiphytes assem- that are specialized on moss require 5.4 The general polygon development We observed marked variations insize the data sedimentation indicate record that of various the1.1 sources polygon. and The contributed that grain- to the the influencetively minerogenic high of input TOC riverine in values flooding Subunit and wasocladus TOC/TN low, cossonii ratios. which The is vegetation supported wasof by dominated wet the by environments; rela- de Klerkspecies et on dry al. rims. (2011),also Thus found the only present-day sparse polygon distributions centre of was this a wet depression, even input and a temporary lowthus water produced table aerobic may conditions, also whichcontent have due may promoted to in oxygen higher turn infiltration decomposition and have rates,(Schirrmeister reduced as et is the al., also organic 2011). suggested matter by high TOC/TN ratios source water are possibledicated reasons that for the variations bulk-organic in materialinate the is dominated against by heavy moss remains.as carbon Mosses vascular isotopes discrim- plants) during due1989; photosynthesis to Peisker, 1984). the (although A absence high not of hydrogencontributed as carbonate any by content strong riverine epidermis in waters, the or may source stomata also water, (Farquhar probably lead to et high al., isotopeinput values. (dilution e (which is abundant inwater Unit level 2) and can prefers growand more Philippi, under terrestrial 2000). more habitats unstable than conditions with variable EM1 scores and the moss record. Changes in the composition of the vegetation and 1) indicates a relatively stable pond with a steady water level, while 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | and in the Meesia tri- Larix Scorpidium Scorpidium Scorpidium Gomphonema and Gomphonema lager- -type and Tabellaria flocculosa (and -type percentages and the low- Navicula vulpina erentiate between individual sub- ff and by the monospecific Alnus fruticosa 4090 4089 Alnus fruticosa Scorpidium scorpioides Tabellaria flocculosa just invaded the area at that time. Favourable growing condi- (indicators of relatively stable conditions in an established en- which often prefers submerged habitats (Miller, 1980), suddenly became toward the top of the section can be recognized in Section B, which may vegetation occupying the permanent waterbody. A decrease in ). The diatoms indicate a shallow water level between swamp mosses. De- (indicators of unstable and disturbed conditions) and ) indicates that a permanent water-filled pond existed for at least some periods adjustment mechanisms The accumulation of Subunit 1.3 saw the start of conditions similar to those of the The grain-size data indicate that riverine flooding again became more common dur- The riverine sediment input was low during the accumulation of Subunit 1.2 The poly- in the initiation andlead development to of an polygons. increase Rapidly in tensile falling elongation temperatures within in the autumn soil substrate, which then begins to disturb the dynamic equilibriumcal within regulatory the mechanisms polygon such as that plantChapin is colonisation III, otherwise (Epstein et 1991), maintained al., by moisture, 2012;1980; lo- Shaver summer and Vitt, heating 1995; and Woo soil(Chernov and thawing and Guan, (Peterson Matveyeva, 2006), and 1997). andin Billings, Through ice the these wedge biotope internal growth is or adjustmentsthe reconfigured peat the impact and accumulation equilibrium of feedbacks the canClimatic external factors occur controls and that (Harding a loose either et soil reduce al., substrate 2002; or may represent Oechel amplify the and primary Vourlitis, external 1994). controls North Siberian Lowland and thatcaution, inference also concerning be polygon applied developmentbasis can, to of with other the spatial polygons and in temporalof analyses the north-eastern of same this Siberia, polygon area. that on Weand the polygon Anabar internal hypothesize, development River adjustment on is lowlands processes. the driven Factors byclimate, acting on both overall a external soil (supra-) controls substrate, regional scale or such river as flooding exert pulses of external influence that Subunit 1.3, indicating the most favourable growing conditions in5.5 the entire record. Polygon development as a function of external controls and internal The studied polygon is partcentred of polygon a large with polygonal rims field1997; and between Meyer, has 2003). the the We adjacent typical therefore form polygons assume of (Chernov a that and low- it Matveyeva, represents a model polygon for the scorpioides indicate a slight lowering oftion the or water a level decrease as in a waterarea result influx was during of recent characterized either times. an by The increaseest the vegetation in in Poaceae highest evapora- the pollen surrounding percentages of the entire section, particularly in the upper part of scorpioides dicated by the dominance of vironment) co-occur in one andresolution the of same the sample samples which may wasunits. indicate not However, that high the the enough temporal dominance toheimii di of within this subunit. Aswith was an expansion the of case tundra elements for in Subunit the 2.1, surrounding area. thispresent day. polygon The stage minerogenic co-occurred sume influx to is be dominated a result by of a lateral fine water flow silt through fraction the which polygon body. we A as- stable stage is in- ing Subunit 2.2, but notwith to mutually exclusive the habitat same requirements extentquetra such as as in Subunit 2.1.Scorpidium Interestingly, scorpioides organisms spite of these indicationsscorpioides of rather stableestablished conditions in within both the Corethe polygon, conditions C within and Subunit Sectionto 1.2 a B changed permanently in from establishedScorpidium the a pond scorpioides middle temporarily or water-filled part the depression tions hydrological of can conditions this be did inferred subunit. not frompolygon Either the change rim high but and proportions upland of vegetation, and the reduced proportion of Poaceae. flooding along the banks of the Anabar River. gon was fully coveredproportion by of moss specialized as epiphytic indicated diatomslagerheimii by growing on both mossy the habitats high ( VPM ratio and the high turn have led to a lower water absorbance capacity and eventually to more extreme 5 5 25 15 20 10 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | : Oven- 1 − ) can be dif- Poaceae or Andromeda, Pedicularis ected by slow lateral water inflow ff 4092 4091 Larix, Vaccinium, Dryas cult to predict. We tentatively infer from our records ffi (1) The present-day spatial vegetation patterns are closely related to abiotic factors: Our records suggest that the controlling factors discussed above may be interdepen- It is assumed that the crackinitiated shape of a polygon is the result of interactions Polygons in Canada have been found to develop on sediments of various glacial and factor. Rim vegetation (dominated by ferentiated from vegetation in the rim-to-pond transition zone ( 6 Conclusions The low-centred polygon in thisand study time, is with at an distinctiveresearch advanced vegetation are stage as patterns. of follows: The succession in main space conclusions drawnwe from observed our the elevation above or below the water level to be the main controlling climate change is complex andthat di higher temperatures andties reduced being flooding characterized would by resultsediment high in ratio), moss the a polygon productivity low communi- moss. (with pH, a high and moss a to specialized minerogenic diatom community that is epiphytic on cumulation of Unit 2 representsuccession long-term disturbance within and the instability in low-centredinput the polygon as sedimentary initiated indicated by forpioneer repeated example taxa) phases by and of the thehave large sediment high led number to diversity species of of exclusion). benthic mosses taxa present (which (as are concurrencedent often may with not regards to yet more their timing extreme and during strength. the Flooding, colder for climatic example, was periods. found Thus to the be response of a polygon to level of development. We assumethe that accumulation a of relatively stable Unit stage 1,of was as the established suggested during plant by the coverof relatively within low tolerance, the diversity the in pond, complex the thediatoms), structure plant-to-plant and dominance a interactions of generally (e.g. high organisms a bioproductivity. with In high contrast, a some number narrow phases of range during epiphytic the ac- interrupted by the impact of this new control, but subsequently returned to the previous terized by a high planktonic diatom component. The development of the polygon was ment, which is what we proposeWe for assume our polygon that record the from thethrough polygon’s Anabar the development River lowlands. was polygon a duringduring the the accumulation accumulation ofter of the velocity sediments Unit was of 2 high Unitsand. the enough 1. However, polygon to the In flooding transport was contrast, would medium-grained,sented repeatedly only and by flooded have even been the and coarse-grained, seasonal mosslevel the as and during the wa- diatom vegetation the record) (repre- majorthe does growing deposition not season. of indicate the A a sediments long-term permanently at flood high 20.5 cm probably water core did length occur in during Core C, which are charac- fluvial origins (Burn, 1990;for the Fortier polygon and field Allard, insands which 2004). our from However, studied the the polygon original is Anabarvelopment. located substrate Although River, probably polygons but consisted of in thesethe river Siberian may rivers lowlands themselves have typically have already seldom occur had been along considered a river to history banks, be drivers of of soil polygon de- develop- pret an initial depressionthe stage with first waterlogged unit conditions followedtime reflected by periods by successive (Chernov deposition and deepening of Matveyeva, of 1997). the depression duringbetween subsequent its position within the2007; landscape Minke and et the nature al.,Anabar of 2007). River. the Our soil polygon substrate (French, is situated within an old meander belt of the spring, and then freezes forming ice-veinsthe which following depending summer on and their either lengthmanovsky, fill thaw 1985). with during The sediment annual or initiate growthden, perennial 1990) of ice-wedges lifts the (Ro- the wedges ambient soil (approximatelysequence substrate 1 of and mmyr the forms rim elevated polygonal uplift rims. a As depression a then con- develops in the polygon centre. We inter- crack (French, 2007). Meltwater or river water fills these cracks during the subsequent 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ” ¨ ohmer ect suc- ff ert, M., and ff indicating that Meesia trique- ¨ unchen, 2004. , 2011. Scorpidium scorpioides 1500 yr of recorded peat accumulation. ∼ ¨ ur Mitteleuropa und angrenzende Gebiete (Mit 4094 4093 ers depending on the stability of the environmental con- ff 10.1016/j.quascirev.2010.12.026 The study is a contribution to the joint Russian-German project entitled ) and in the pond (comprised solely of is limited by a higher water level in the pond). is abundant in the moss spectra, and benthic taxa in the diatom record). However, Carex Cyperaceae, Swedish Natural Science Research Council, Stockholm, 1969. Norway, Denmark, East Fennoscandia andSalicaceae-Cruciferae, Iceland) Swedish with Museum morphological of descriptions: Natural part History, Stockholm, 3. 1981. 120 Tafeln, 29 Abbildungen und 13 Tabellen), 1. Auflage, Pfeil, M gie, Bodemcultuur en Warenkennis, Veenman, Wageningen, 1947. Norway, Denmark, East Fennoscandia and Iceland) with morphological descriptions; Part 2, University Press, St. Petersburg, 2003. Quaternary-evidence from pollen13–25, records 2002. of the Bykovsky Peninsula, Polarforschung, 70, terich, S., and Hubberten,(Arctic H.-W.: Siberia) Vegetation during and Late30, climate Quaternary 2182–2199, history doi: inferred in from pollen the records, Laptev Quaternary Sea Sci. region Rev., Morphological Descriptions (Sweden, Norway, Denmark,Swedish Natural East Science Fennoscandia, Research and Council, Iceland), Stockholm, 1994. Hubberten, H. W.: Paleoenvironmental changes in Northeastern Siberia during the Late Ecosystems, vol. 209, editedWein, R. by: W., Osawa, Billings, W. A., D.,Netherlands, Golley, Zyryanova, F., 41–58, Lange, O. O. 2010. L., A., Olson, Matsuura, J. S., Y., and Kajimoto, Remmert, T., H., Springer, (3) The development of polygons in flood plains is not straightforward and is influ- (2) The peat composition di Polygons in tundra wetlands: State and dynamics under climate variability in polar regions Birks, H. J. B. and Birks, H. H.: Quaternary Palaeoecology, Edward Arnold, London, 1980. Berggren, G.: Atlas of seeds and small fruits of northwest-European plantBeug, H. species J.: (Sweden, Leitfaden der Pollenbestimmung f Berggren, G.: Atlas of seeds and small fruits of Northwest-European plant species (Sweden, Beijerinck, W.: Zadenatlas der Nederlandsche Flora ten Behoeve van de Botanie, Palaeontolo- Anon: The Diatoms of Russia and Adjacent Countries (Fossil and Modern), St. Petersburg Anon: The Diatoms of the USSR, Nauka, Leningrad, 1992. Anon: The Diatoms of the USSR, Nauka, Leningrad, 1988. Anon: The Diatoms of the USSR, Nauka, Leningrad, 1974. Andreev, A. A., Schirrmeister, L., Tarasov, P. E., Ganopolski, A., Brovkin, V., Siegert, C., Wet- Andreev, A., Schirrmeister, L., Siegert, C., Bobrov, A. A., Demske, D., Sei Anderberg, A.-L.: Atlas of Seeds: And Small Fruits of Northwest-European Plant Species with Abaimov, A. P.:Geographical distribution and genetics of Siberian Larch species, in: Permafrost References Acknowledgement. “ (Russian Foundation forForschungsgemeinschaft, Basic DFG grant Research, no. RFBR HEus 3622-16-1). grant during We thank the no. all fieldworklaboratories 11-04-91332-NNIO-a, colleagues (Ute and who Deutsche Bastian, those helped Antje who(Hanno Meyer) Eulenburg, assisted at Liv the with Heinecke) Alfred thefor Wegener and the Institute analytical the help in work with Potsdam. Stable map Furthermore, in Isotopefor preparation, we English M. the Laboratory thank proofreading. Wieczorek Th. geochemical for B support with R graphics and E. A. Manning cession after such pulsesequilibrium of under external the new influence, environmental readjusting conditions. the system to a dynamic coarse grained sand withinadapted the to deposits), instability a and communitytra sediment became supply established that (i.e. was despite a changes community in in the which compositionpond of and the rim pond has community, not the changed general position over the of last the enced by the river, which mayinternal in turn regulating be related factors to within climatic conditions. the However, various polygon react to these changes and a Carex ditions. Stable conditionswhen occurred submerged during moss periods communitiespolygon with overgrown centre. by little During epiphytic or times diatoms no dominated of riverine the repeated flooding, riverine flooding (indicated by medium to or 5 5 30 25 20 15 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | er, E.- ¨ ob, K., ff annexes, , 1970. + , 2012. , 2010. http://www.mobot.org/ 10.1016/0033-5894(70)90013-X (last access: 25 February 2011), 2008. ¨ uge der Vegetationskunde, Springer-Verlag, er, E. M.: Element redistribution along hydraulic ff 4096 4095 doi:10.1088/1748-9326/7/1/015506 10.1111/j.1365-2486.2009.02110.x , 2012. , 2011. , 2012. , 1990. , 2008. , 1994. alo Museum of Science,USA, available at: , 1995. ff W), Ecology, 85, 963–978, 2004. ◦ N, 80 ¨ uber, M., Kutzbach, L., Langer, M., Minke, M., Muster, S., Piel, K., Pfei ◦ ¨ unnemann, B., Hartmann, K., Diekmann, B., Opitz, S., Paprotzki, M., Runge, M., doi:10.5194/bgd-9-12343-2012 ¨ as, L.: Amblystegiaceae – Drepanocladus, Bryophyte Flora of North America, Pro- 10.1016/j.quascirev.2011.06.016 10.1007/BF02334251 10.1002/ppp.3430010103 10.1029/94GB03156 bilization in a polygonal12376, tundra soil of the Lena-Delta, Biogeosciences Discuss.,visional 9, 12343– Publication, Bu plantscience/bfna/v2/AmblDrepanocladus.htm feedbacks at the tundra-taiga interface, Ambio, 12, 47–55, 2002. storage and turnover in high-latitude soils, Glob. Change Biol., 6, 196–210, 2002. 2004. north-eastern Germany, J. Biogeogr., 35, 1308–1322, 2008. ics of aclimate low-centred change ice-wedge polygon duringdoi: near the Chokurdakh last (NE ca Yakutia, NE 1250 Siberia) years, and Quaternary Sci. Rev., 30, 3013–3031, synthesis, Ann. Rev. Plant Biol., 40, 503–537, 1989. and redox gradients ofAm. low-centered J., polygons, 68, Lena 1002–1011, Delta, 2004. northern Siberia, SoilIsland, Sci. Canadian Soc. arctic archipelago, Can. J. Earth Sci., 41, 997–1012, 2004. ues of freshwater diatoms fromdoi: The Netherlands, Netherlands J. Aquat. Ecol., 28, 117–133, Bylot Island (73 Dynamics of aboveground phytomass ofdecades, the Environ. circumpolar Res. Lett., Arctic 7, tundra 015506, during the past three lowland relief, Quaternary Res., 1, 103–120, doi: spective on polygon mires, MSc2007. thesis, Greifswald University, Greifswald, 45 pp. development atdoi: Mayo, Yukon Territory,1997. Permafrost Periglac. Process., 1, 3–14, Yang, S., and Lockot, G.:Donggi Cona, Windows NE into Tibetan the Plateau, past: 14, on-shore 2507, EGU2012-2507, high-stand 2012. sediments from lake Wien, 1964. Grigoriev, M., Gr M., Stoof, G., Westermann,characteristics S., Wischnewski, of K., climate, Wille, permafrost,in C., and the and Hubberten, Lena land H.-W.: River coverdoi:10.5194/bgd-9-13627-2012 Baseline Delta, from Siberia a (1998–2011), new Biogeosciences permafrost Discuss., observatory 9,mulation 13627–13684, in peatlandsdoi: of the former Soviet Union, Global Biogeochem. Cy., 9, 37–46, of polygonal tundradoi:10.1029/2007JG000540 in the Lena River Delta, Siberia, J. Geophys. Res., 113, G03025, Berendse, F.: Shrub expansionGlob. Change may Biol., reduce 16, 1296–1305, summer doi: permafrost thaw in Siberian tundra, ¨ ofle, S., Rethemeyer, J., Mueller, C. W., and John, S.: Organic matter composition and sta- H Heden Hobbie, S. E., Schimel, J. P., Trumbore, S. E., and Randerson, J. R.: Controls over carbon Harding, R., Kuhry, P., Christensen, T. R., Sykes, M. T., Dankers, R., and Linden, S.: Climate French, H. M.: The Periglacial Environment, John Wiley and Sons, New York, 2007. Frahm, J.-P.and Frey, W.: Moosflora, 4., neubearbeitete und erweiterte Auflage, UTB, Stuttgart, Frahm, J. P.: Biologie der Moose, Spektrum Akademischer Verlag, Heidelberg, Berlin, 2001. Fortier, D. and Allard, M.: Late Holocene syngenetic ice-wedge polygons development, Bylot De Klerk, P., Donner, N., Karpov, N. S., Minke, M., and Joosten, H.: Short-term dynam- Fiedler, S., Wagner, D., Kutzbach, L., and Pfei De Klerk, P.: Patterns in vegetation and sedimentation during the Weichselian Late-glacial in Farquhar, G. D., Ehleringer, J. R., and Hubick, K. T.: Carbon isotope discrimination and photo- Dam, H. V., Mertens, A., and Sinkeldam, J.: A coded checklist and ecological indicator val- Epstein, H. E., Raynolds, M. K., Walker, D. A., Bhatt, U. S., Tucker, C. J., and Pinzon, J. E.: Ellis, C. J. and Rochefort, L.: Century-scale development of polygon-patterned tundra wetland, Czudek, T. and Demek, J.: Thermokarst in Siberia and its influence on the development of Donner, N.: Hydrological windows in low-centered arctic polygons, A landscape ecological per- Burn, C. R.: Implications forChernov, palaeoenvironmental Y. I. reconstruction and Matveyeva, N. of V.: Arctic recent ecosystems in ice-wedge Russia, Ecosys. World, 361–508, Dietze, E., W Braun-Blanquet, J.: Pflanzensoziologie: Grundz Botch, M. S., Kobak, K. I., Vinson, T. S., and Kolchugina, T. P.: Carbon pools and accu- Boike, J., Kattenstroth, B., Abramova, K., Bornemann, N., Chetverova, A., Fedorova, I., Fr Boike, J., Wille, C., and Abnizova, A.: Climatology and summer energy and water balance Blok, D., Heijmans, M. M. P. D., Schaepman-Strub, G., Kononov, A. V., Maximov, T. C., and 5 5 30 25 20 30 15 25 10 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ce of the ¨ ¨ ¨ onigstein, onigstein, onigstein, , 1980. ffi ¨ anzend zur , 2011. , 2000. 10.1016/S0016- , 1974. ¨ aßpflanzen: Grundband, 10.2307/2484158 10.7202/004846ar ¨ usswasserflora von Mitteleuropa, ¨ onigstein, 2003. ¨ onigstein, 2001. er, E.-M., and Knoblauch, C.: Methane oxi- ¨ onigstein, 1999. ff 10.1111/j.1365-2745.2011.01823.x 4098 4097 ¨ uber 100 weitere neu definierte Taxa erg 10.1016/0022-1694(74)90005-5 ´ eograph. Phys. Quaternaire, 54, 41, doi: , 1999. ˆ Akutii, Nauka, Moskva, 1975. ¨ undung einer neuen Gattung der Naviculaceae, A. R. G. Gantner Verlag, K ¨ ¨ onigstein, 1996. usswasserflora von Mitteleuropa, A. R. G. Gantner Verlag, Stuttgart, 1993. Sea, Vol. The Expeditionhaven, 29–48, LENA 2003. 2002, BerPolarforschung und Meeresforschung, Bremer- North American studies, Bull. Torr. Bot. Club, 107, 373–391, doi: Alaska, J. Hydrol., 23, 233–246, doi: a long-term study, G sula, northern Siberia, J. Veg. Sci., 5, 813–828, 1994. Soc., 13, 69–96, 1997. Petersburg, 2000. vol. 2, Gustav Fischer Verlag, Stuttgart/Jena, 1986. dation associated with submerged brownpolygonal mosses reduces tundra, methane J. emissions Ecol., from 99, Siberian 914–922, doi: Moospflanzen und Farnpflanzen Europas,Heidelberg, 6. 1995. Aufl., Spektrum Akademischer Verlag, Berlin, 2002. cymbellopsis, Afrocymbella, A. R. G. Gantner Verlag, K (Yugorsky-Shar Strait), Koeltz Scientific Books, K K Begr 1996. doemov 2000. icula sensu lato, Frustulia, A. R. G. Gantner Verlag, K sessment of abiomes modern from pollen-climate northern calibrationfrom Yakutia set the (eastern Lena for Siberia) Delta, Arctic Palaeogeogr. and Palaeocl., tundra submitted, its 2013. and applicability northern to a taiga Holocene record S Atlas of the NorthernEuropean Circumpolar Union, Luxembourg, Region, 2010. Europeen Comission, Publications O Quaternary Deposits of the USSR, Nauka, Moscow, 1965. laev, A. N.,Zakharova, Shurduk, V. I., I. Cherosov, M. F., M., Lytkina,Kuznetsova, Nikolin, L. E. V., L. Pestryakov, G., B. N., Sosina, P., Mironova, N. Ermakov, S.tia: K., I., Elements N. Troeva, and E. of Sleptsova, I., Ecology B., N. Gogoleva, and P.:Vegetation P. Nikitina, Plant A., ofIsaev, A. Sociology, Yaku- in N. P., Cherosov, The M. Far V., M., North, Efimova, and2010. vol. Karpov, 3, A. N. edited S., by: P., Springer Troeva, E. Netherlands, I., Dordrecht, 143–260, 19. Aufl. 2005., Spektrum Akademischer Verlag, Heidelberg, Berlin, 2005. utaries of the Lenathe Trans-Baikal and Highlands, Anabar Geochim. Cosmochim. draining7037(99)00045-9 Acta, the 63, basement 967–987, terrain doi: of the Siberian Craton and ¨ ager, E. J.: Rothmaler – Exkursionsflora von Deutschland, Bd. 2: Gef Miller, N. G.: Mosses as paleoecological indicators of lateglacial terrestrial environments: some Meyer, H.: Studies on recent cryogenesis, in: Russian-German Cooperation System Laptev Luthin, J. N. and Guymon, G. L.: SoilMackay, moisture-vegetation-temperature J. relationships in R.: central Thermally induced movements in ice-wedge polygons,Matveyeva, western N. V.: arctic Floristic classification coast: and ecology of tundra vegetation of the Taymyr Penin- Loseva, E. I.: Atlas of Freshwater Pleistocene Diatoms from Northeastern Europe, Nauka, St. Matveev, I. A. (ed.): Agricultural Atlas of the Republic Sakha (Yakutia), Nauka, Moscow, 1989. Longton, R. E.: The role of bryophytes and lichens in polar ecosystems, Spec. Publ.-Brit. Ecol. Krammer, K. and Lange-Bertalot, H.: Bacillariophyceae, in S Liebner, S., Zeyer, J., Wagner, D., Schubert, C., Pfei Lobin, W., Fischer, E., Frahm, J.-P.,Frey, W., and Gams, H.: Kleine Kryptogamenflora, Bd. 4, Die Krammer, K.: Diatoms of Europe. The Genera Cymbopleura, Delicata, Navicymbula, Gompho- Lange-Bertalot, H., Metzeltin, D., and Witkowski, A.: Hippodonta gen. nov. Umschreibung und Krammer, K.: Diatoms of Europe. The Genus Cymbella, A. R. G. Gantner Verlag, K Lange-Bertalot, H. and Metzeltin, D.: Indicators of oligotrophy, Koeltz Scientifc Books, Krammer, K.: Diatoms of Europe, The Genus Pinnularia, A. R. G. Gantner Verlag, K Lange-Bertalot, H. and Genkal, S. I.: Diatoms from Siberia. I. Islands in the Arctic Ocean Komarenko, L. E. and Vasilyeva, I. I.: Prespovodnye Diatomovye i Sinezelenye Vodorosli Vo- Lange-Bertalot, H.: Diatoms of Europe. Navicula sensu stricto. 10 Genera separated from Nav- Klemm, J., Herzschuh, U., Pisaric, M. F. J., Telford, R., Heim, B., and Pestryakova, L. A.: As- Lange-Bertalot, H.: 85 neue Taxa und Katz, N. J., Katz, S. V., and Kipiani, M. G.: Atlas and Keys of Fruits and Seeds Occuring in the Jones, A., Stolbovoy, V., Tarnocai, C., Broll, G., Spaargaren, O., and Montanarella, L.: Soil J Isaev, A. P., Protopopov, A. V., Protopopova, V. V., Egorova, A. A., Timofeyev, P. A., Niko- Huh, Y. and Edmond, J. M.: The fluvial geochemistry of the rivers of Eastern Siberia: III. Trib- 5 5 30 20 25 30 15 10 25 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , , 2011. http://www. http://www. 10.2307/1550495 ¨ a, M., Kultti, S., and , 1982. 10.1016/0169-5347(94)90152-X in Siberian tundra reveals the sea- 10.1016/j.yqres.2011.01.007 2 -Isotopendiskriminierung bei der Photosyn- ff ¨ urttembergs, Ulmer, Stuttgart, 2000. er, E.-M., and Kutzbach, L.: Bulk partitioning , 2000. 10.1038/298156a0 ff 4100 4099 n Island, IV. Annotated list of Bacillariophyta, Nova ¨ utken, T., Gartz, S., and Diekmann, B.: Late Qua- ffi ects of climate charge on land–atmosphere feedbacks ected lakes in central Yakutia (Eastern Siberia) inferred ff , 1990. ff , 2012. , last access date: 25 October 2012, 2007. ¨ , 2012. om, J., Blom, T., Pienitz, R., Smol, J. P.,Douglas, M. S. V., and , 2006. ¨ aliranta, M., Jones, V. J., Self, A., Heikkil ¨ a, H., V 10.1023/A:1008173901591 , last access date 10 January 2008, 2007. 10.1134/S1995425512040105 10.1016/0033-5894(90)90063-Q the growing seasonsonality net ecosystem of exchange its ofdoi:10.5194/bgd-9-13713-2012 carbon CO sequestration strength, Biogeosciences Discuss., 9,Yang, H.: 13713–13742, The HoloceneEuropean thermal Russia, maximum Quaternary Res., and 75, late-Holocene 501–511, cooling doi: in the tundra of NE and Theory: Lectures in Geocryology,British edited by: Columbia, Church, Canada, M. 154–165, and 1985. Slaymaker, S., University of based ondoi:10.1029/2005JG000150 1950–2002 remotely sensed1996–2009, images, Phytosciological Research J.globalbioclimatics.org/default.htm Center, Geophys. Spain Res., [online], available 111, at: G04002, well, P. G., Buck,calibration, C. 0–26 E., cal kyr Burr, BP, G. Radiocarbon, 46, S., 1029–1058, and 2004. Cutler, K. B.: IntCal04 terrestrial radiocarbon age of moderndoi: bottom sediments in SiberianHawaii), Vol. arctic, 1: Systematic descriptions Contemp. of diatoms Probl. of the taxonomic Ecol., orders Fragilariales, 5, Eu- 413–422, world life zones, Nature, 298, 156–159, doi: 1980. in arctic tundra regions, Trends Ecol.1994. Evol., 9, 324–329, doi: Suggests, M.: The veganR-project.org package, Community ecology package, available at: doi: 173 pp., 2008. Holocene dynamics of permafrost-a from diatom records, Quaternary Sci. Rev., 51, 56–70, 2012. microtopography near Atkasook, Alaska, Arctic Alpine Res., 12, 473, doi: these von C 3-und C 4-Pflanzen, Genet. Resour. Crop Evol., 32, 35–65, 1984. ternary vegetation andconstructed environments from in a the 50-kyr2071–2086, fossil Verkhoyansk 2010. pollen Mountains record region from Lake (NE Billyakh, Asia) Quaternary re- Sci. Rev., 29, notiales, Achnanthales, and Navicuales (family Naviculaceae),of Monograph Natural 13, The Sciences, Academy Philadelphia, Pennsylvania, 1966. Hay, M. B.: Paleohydrology inferred from diatoms24, in 93–107, northern doi: latitude regions, J. Paleolimnol., Hedw., 26, 205–223, 1975. Oxford, 1991. position, surface height and thawa depth microtopographical in characterisation polygon of mires the357–368, in active 2009. the layer, Yakutian Arctic Permafrost (NE Periglac. Process., Siberia): 20, development and dynamics ofPeatlands Int., polygon 1, mires: 36–40, 2007. examples from Northeast Yakutia (Siberia), ¨ uller, S., Tarasov, P. E., Andreev, A. A., T Salonen, J. S., Sepp Runkle, B. R. K., Sachs, T., Wille, C., Pfei Romanovsky, N. N.: Distribution of recently active ice and soil wedges in the USSR, in Field Riordan, B., Verbyla, D., andRivas-Martinez, McGuire, S. A. and D.: Rivas-Saenz, Shrinking S.: ponds Worldwide in Bioclimatic subarctic Classification Alaska System, Reimer, P. J., Baillie, M. G. L., Bard, E., Bayliss, A., Beck, J. W., Bertrand, C. J. H., Black- Patrick, R. and Reimer, C. W.: The diatoms of the United States (exclusive of Alaska and Palagushkina, O. V., Nazarova, L. B., Wetterich, S., and Schirrmeister, L.: Diatoms Post, W. M., Emanuel, W. R., Zinke, P. J., and Stangenberger, A. G.: Soil carbon pools and Ovenden, L.: Peat accumulation in northern wetlands, Quaternary Res., 33, 377–386, Peterson, K. M. and Billings, W. D.: Tundra vegetational patterns and succession in relation to Oksanen, J., Kindt, R., Legendre, P., O’Hara, B., Stevens, M. H. H., Oksanen, M. J., and Pestryakova, L. A., Herzschuh, U., Wetterich, S., and Ulrich, M.: Present-day variability and Oechel, W. C. and Vourlitis, G. L.: The e Pestryakova, L. A.: Diatomovye kompleksy ozer Yakutii, Yakutsk State University, Yakutsk, Nebel, M. and Philippi, G.: Die Moose Baden-W Peisker, M.: Modellvorstellungen zur Kohlensto M Moser, K. A., Korhola, A., Wekcstr Moore, P. D., Webb, J. A., and Collinson, M. E.: Pollen Analysis, 2nd ed., Blackwell Science, Moore, J. W.: Benthic algae of southern Ba Minke, M., Donner, N., Karpov, N., De Klerk, P., and Joosten, H.: Patterns in vegetation com- Minke, M., Donner, N., Karpov, N. S., De Klerk, P., and Joosten, H.: Distribution, diversity, 5 5 30 25 20 15 30 10 20 25 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , , , 1989. , 2011. 10.1007/BF02775085 10.1007/BF00119798 10.1007/BF00026549 er, E.-M.: Organic carbon and 10.1016/0033-5894(90)90021- ff , 2001. 10.1016/S0037-0738(03)00235-5 , 1995. doi:10.1029/2011JG001647 4102 4101 , 2002. , 2012. , 1995. , 2006. ¨ uber die letzten 1500 Jahren, University of Potsdam, Pots- 10.1007/BF00045195 10.1191/095968301680223486 ¨ aoumwelt 10.1002/ppp.565 10.2307/3243306 doi:10.5194/bgd-9-17263-2012 ¨ els, F. J.: Vegetation of zonal patterned-ground ecosystems along the North America 10.1111/j.1654-1103.2002.tb02117.x ¨ a, H. and Birks, H. J. B.: July mean temperature and annual precipitation trends during , 1990. total nitrogen stocks in17311, soils of the Lena River Delta, Biogeosciences Discuss., 9, 17263– Vegetation, 118, 131–137, doi: western interior Canada, QuaternaryC Res., 33, 231–240, doi: ponds in a polar17, 309–323, oasis doi: environment, Canadian High Arctic, PermafrostGeocryological Periglac. map Process., of Russia and neighbouringUniversity, Russian republics, Ministry 1 : of 2 Geology 500 (Williams, 000language P.J. scale, version Moscow and of State Warren, the M. geocryological T., map 2003),a of The project Russia English of and neighbouring Moscow republics State (2nd University, edn.), Department of Geocryology, Moscow,discontinuous 1991. permafrost near Council, Alaska,2003. Permafrost Periglac. Process., 14, 151–160, macrofossil and lithological analysis, University of Potsdam, Germany, 2010. sediment: an overview, Hydrobiologia, 176–177, 125–149, doi: solving the explicit1997. mixing problem, Math. Geol., 29, 503–549,of doi: deep-sea clastics,2003. Sediment. Geol., 162, 39–62, doi: ter ostracods from modern periglacial environments in the Lena River Delta (Siberian Arctic, Russia): geochemical applications for palaeoenvironmental39, reconstructions, 427–449, J. 2008. Paleolimnol., gist, 98, 218, doi: Dani Arctic bioclimate gradient, Appl. Veg. Sci., 4, 440–463, 2011. etation of South and Southeast Sweden, Plant Ecol., 44, 25–35, doi: berten, H. W.: FossilSiberian organic Arctic, matter J. characteristics Geophys. Res, in 116, permafrost G00M02, deposits ofthe the Holocene northeast in the Fennoscandian tree-lineHolocene, area: 11, pollen-based 527–539, climate doi: reconstructions, The contrasting arctic vegetation types, Ecol. Monogr., 61, 1–31, 1991. 1981. tal gradients ofdoi: high-arctic mires in Sassendalen, Svalbard, J. Veg. Sci., 13, 875–884, Rekonstruktion der Pal dam, Germany, 2012. Zubrzycki, S., Kutzbach, L., Grosse, G., Desyatkin, A., and Pfei Zoltai, S. C. and Vitt, D. H.: Canadian wetlands: environmental gradients and classification, Zoltai, S. C. and Vitt, D. H.: Holocene climatic change and the distribution of peatlands in Yoshikawa, K. and Hinzman, L. D.: Shrinking thermokarst ponds and groundwater dynamics in Yershov, E. D., Kondratyeva, K. A., Zamolotchikova, S. A., Trush, N. I., and Dunaeva Ye, N.: Woo, M.-K. and Guan, X. J.: Hydrological connectivity and seasonal storage change of tundra Wolter, J.: Late Holocene development of a polygon mire in NW Yakutia inferred from plant Weltje, G.: End-member modeling of compositional data: numerical-statistical algorithmsWeltje, for G. J. and Prins, M. A.: Muddled or mixed? Inferring palaeoclimate from size distributions Walling, D. E. and Moorehead, P. W.: The particle size characteristics of fluvial suspended Wetterich, S., Schirrmeister, L., Meyer, H., Viehberg, F. A., and Mackensen, A.: Arctic freshwa- Vitt, D. H.: Patterns of bryophyte diversity in peatlandsWalker, of D. continental A., western Kuss, Canada, P., Bryolo- Epstein, H. E., Kade, A. N., Vonlanthen, C. M., Raynolds, M. K., and Tyler, C.: Soil acidity and distribution of species on tussocks and interspaces in schoenus veg- Shaver, G. R. and Chapin III, F. S.: Production: biomass relationships and element cycling in Schirrmeister, L., Grosse, G., Wetterich, S., Overduin, P.P.,Strauss, J., Schuur, E. A., and Hub- Sepp Vanderpuye, A. W., Elvebakk, A., and Nilsen, L.: Plant communities along environmen- Schilling, N.: Eine isotopenbasierende Analyse an Moosen der nordsibirischen Tundra zur 5 5 20 15 10 25 30 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Ce- ), humps Aulacom- Aulacom- Sphagnum ), humps to- ) and tundra ), grass bogs Salix pulchra, S. ), KIA46253 ), KIA46254 ) KIA46256 ) KIA44744 ) KIA46257 ) and ) with lichens and ), dwarf shrub tundra ), dwarf shrub tundra ), dwarf shrub tundra ( , willow ( ) and dwarf shrubmountain tun- Larix gmelinii Amblystegiaceae Amblystegiaceae Amblystegiaceae Amblystegiaceae Amblystegiaceae ), lichens and mosses ( ), lichens and mosses ( ) with tundra bogs on humps and depressional grass 1600 yr BP for the bottom samples from alaskanum, Cetraria cucullata (0.97 mg) (1.22 mg) (1.1 mg) (2.5 mg) (2.47 mg) (2.3 mg) (1.53 mg) Salix pulchra, S. alaxensis ∼ ) and valley meadows from horsetail and alaskanum, Cetraria cucullata var. ) ) var. Duschekia fruticosa Carex stans Betula exilis, Salix pulchra Betula exilis, Salix pulchra 4104 4103 range) Lab. Betula exilis, Salix pulchra σ and Alectoria ochroleuca, Coelocaulon divergens valleys and coasts 2435 420–539 417–568 Plant seed, wood (2.3 mg) Plant seed (0.7 mg) KIA38752 KIA38753 27 1426–1495 Plant seed (1.9 mg) KIA39094 2525 1536–1635 Mosses ( 23 1213–127525 Mosses ( 1391–143120 Plants 1392–1436 (2.47 mg) Mosses (unidentified23 species) 1430–1471 KIA44742 Mosses (unidentified22 species) 1387–1419 KIA44743 Mosses ( 22 1368–1382 KIA46255 Mosses ( 26 1398–1440 Mosses ( 1436–1516 Plants (3.5 mg) KIA39095 , ± ± ± ± ± ± ± ± ± ± ± ± Aulacomnium turgidum, Hylocomium splendens together with Alectoria ochroleuca, Coelocaulon divergens Sphagnum balticum, Sphagnum warnstorfii Eriophorum vaginatum 5.56.58.5 791 544 535 40.3 1587 12.515.5 435 20.5 568 24.5 699 25.5 518 407 Equisetum arvense, Poa alpigena ), Dryas punctata, Cassiope tetragona Legend for the vegetation types (Fig. 1c) according to the agriculture map of Yakutia Results of AMS dating indicating an age of Vaccinium vitis-idaea, V. uliginosum, Ledum palustre Vaccinium vitis-idaea, V. uliginosum, Ledum palustre Eriophorum polystachyon, Arctophilia fulva bogs traria cucullata mixed with sectionsmosses of with widely Ledum and spaced stone larch bramble forests ( nium turgidum, Hylocomium splendens ( nium turgidum, Hylocomium splendens gether with tundra bogs dra ( mosses ( bogs together with various types ofgrass willow ( ( ( glauca ( Section A 19.6 426 Section/core Depth Radiocarbon age [cal yr [cm] AD]Section BCore Fraction C (C content) 49.5 [yr BP] 3.5 1566 Sample (2 ID 342 3: Widely spaced dwarf shrub tundra ( 2: Widely spaced dwarf shrub tundra ( Vegetation in the river valley with dominant6: larch forests Leaves mosses ( Rock desert and mountain tundra 4: Lichens ( Vegetation of riparian areas 5: Polygonal peat tundra with thickets of Subarctic tundra vegetation 1: Widely spaced dwarf shrub tundra ( Table A1. (Matveev, 1989). sections A and B, and relatively homogeneous ages for Core C (core length: 27 cm). Table 1. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ¨ ¨ utzingutzing Epiphytic Epiphytic ¨ uller) Haworth Planktonic ¨ utzing) Czarnecki Epiphytic ¨ ¨ utzing Planktonic utzing Epiphytic ¨ ¨ utzing Epiphytic utzing Epiphytic (K PetersonKrammer(Ehr.) Simonsen(M Planktonic (Grun.) Krammer Benthic Ehr. Benthic K Pant. Benthic (Ehr.) K (Ehr.) K (Grun.) CleveCholnokyCleve-Euler Epiphytic Reimer. Planktonic Epiphytic KrammerK (Grunow) Epiphytic Krammer Epiphytic (Ehrenberg) Krammer Epiphytic Epiphytic Epiphytic (Rabenh.) Grun.ex A.S.(Bleisch) Mann Epiphytic Epiphytic Epiphytic (Kutz.) Breb.K Ehr.(Ehr.) Mills.(Ehr.) Grun. Epiphytic Ehr.Brevisson(Kutz.) Grun.Ehr.(Dillw.) Rabenh. Epiphytic Ehr. Epiphytic Epiphytic Hust. Epiphytic Epiphytic Desm. Epiphytic Epiphytic Hust.(Nitzsch.) Lange-Bertalot Epiphytic Ehr. Epiphytic Ehr. Epiphytic Ehr. Epiphytic Cleve Planktonic K Epiphytic Ehr.(Ehr.) Grun.(Hantzsch.) Grun. Epiphytic Epiphytic Ag. Epiphytic Epiphytic Benthic Benthic Epiphytic Planktonic 4106 4105 spp. Epiphytic spp. Epiphytic spp. Planktonic spp. Benthic spp. Epiphytic spp. Planktonic spp. Epiphytic spp. Benthic spp. Epiphytic spp. Benthic spp. Epiphytic Achnanthidium minutissimum Amphora inariensis Aulacoseira granulata Aulacoseira Caloneis Cocconeis placentula Cyclotella meneghiniana Cyclotella ocellata Cyclotella Cymbella heteropleura Cymbella incerta Cymbella mesiana Cymbella paucistriata Cymbella proxima Cymbella Cymbopleura cuspidata Cymbopleura hybrida Cymbopleura inaequalis Diploneis Encyonema cesatii Encyonema silesiacum Achnanthes Adlafia bryophila Aulacoseira subarctica Caloneis thermalis Cymbella gracilis Cymbella tynnii Epithemia sorex Epithemia Eunotia arcus Eunotia bilunaris Eunotia faba Eunotia formica Eunotia lunaris Eunotia minor Eunotia monodon Eunotia pectinalis Eunotia praerupta Eunotia pseudopectinalis Eunotia Fragilaria capucina Fragilaria construens Fragilaria Fragilaria ulna Gomphonema acuminatum Gomphonema clavatum Gomphonema gracile Gomphonema lagerheimii Gomphonema parvulum Gomphonema Gomphonema subtile Hantzschia amphioxys Hantzschia elongata Hantzschia Melosira varians Epithemia adnata (Continued.) Summary list of determined diatom taxa (Core C) with life form information. Taxon code Taxon name Author Life form AchMin AmpIna AulGra AulSp. CalSp. CocPla CycMen CycOce CycSp. CymHet CymInc CymMes CymPau CymPrx Cym CymCus CymHub CymEhr DipSp. CymCes CymSil AchSp. NavBry AulSub CalThe CymGra CymTyn EpiSor EpiSp. EunArc EunBil EunFab EunFor EunLun EunMin EunMon EunPec EunPra EunPse EunSp. FraCap FraCon FraSp. FraUln GomAcu GomCla GomGra GomLag GomPar GomSp. GomSut HanAmp HanElo HanSp. MelVar Taxon code Taxon nameEpiAdn Author Life form Table A2. Table A2. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ¨ oller Planktonic ¨ oller Epiphytic ¨ ¨ ¨ ¨ utzingutzingutzingutzing Benthic Benthic Benthic Benthic ¨ ¨ CleveK KrasskeHust.K K Ehr.Lange-BertalotK (Krammer Benthic and Lange-Bertalot) Benthic Benthic (Ehr.) KrammerI.Kiss. Benthic (Ehr.) Cleve Benthic (Ehr.) Cleve Benthic Grun. Benthic Ehr.CleveEhr.(Lagerstedt) Benthic CleveW.Sm. Benthic Benthic (Ehr.) Cl.(Grun) CleveCleve Benthic Benthic Benthic Benthic Benthic Benthic Benthic Benthic Benthic utz.) D. G. Mann Benthic utz.) Cleve and M (Lungb.) Kutz.(Roth.) Kutz.(Ehr.) Mills Planktonic Epiphytic Epiphytic Krammer(Nitzsch.) Ehr.(Ehr.) Meresch.(Grunow) Williams and Round(Gregory) Kociolek and Stoermer(Ag.) L.-B. Epiphytic Epiphytic (Ehr.) O. Mull.(K Kutz.Peterson Benthic Benthic Benthic Rabh.(Nitzsch.) Ehr.(Ehr.) Cleve and M Ehr Epiphytic Epiphytic (K Benthic Benthic Benthic Benthic Epiphytic 4108 4107 spp. Planktonic spp. Benthic spp. Benthic spp. Benthic spp. Benthic spp. Benthic spp. Benthic Tabellaria flocculosa Tetracyclus glans Stephanodiscus Tabellaria fenestrata Sellaphora pupula Pinnularia viridis Placoneis gastrum Pseudostaurosira brevistriata Reimeria sinuata Rhoicosphenia abbreviata Rhopalodia gibba Sellaphora laevissima Stauroneis agrestis Stauroneis anceps et f.gracilis Stauroneis phoenicenteron Stauroneis Staurosira venter Stephanodiscus minutulus Pinnularia subgibba Staurosirella pinnata Navicula amphibola Navicula cryptocephala Navicula ignota Navicula pseudotuscula Navicula radiosa Navicula rhynchocephala Navicula semen Navicula Navicula trivialis Navicula vulpina Navicula jaagii Neidiopsis Neidium ampliatum Neidium dilatatum var. jacuticum Neidium hitchcockii Neidium iridis Neidium Nitzschia amphibia Nitzschia Pinnularia borealis Pinnularia brevicostata Pinnularia gibba Pinnularia intermedia Pinnularia interrupta Pinnularia microstauron Pinnularia Pinnularia stauroptera Pinnularia streptoraphe (Continued.) (Continued.) TabFlo TetDla SteSp. TabFen SelPup PinVir NavGas FraBre CymSin RhoCur RhoGib SelLae StaAgr StaAncGr StaPho StaSp. SteMin FraConVe Taxon code Taxon namePinSgi AuthorFraPin Life form Taxon code Taxon nameNavAmp NavCry NavIgn NavPss NavRad NavRhy NavSem NavSp. AuthorNavVul NavJaa NesSp NeiAmp NeiDil NeiHit NeiIri NeiSp. NitSp. Life form PinBor PinBrc Pingib PinInr PinInt PinMic PinSp. PinStr NavLan NitAmp PinSth Table A2. Table A2. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

. - 44 (c)

floodplain

's 45 The elevation of the is located south of the

(b) ) the river

LY on - erences between a shallow ff

surface is covered with a shrub SA - 07 ( land meander meander and the land surface is covered with The elevation of the permafrost table,

he he ed (c) (d)

abandon 4109 4110 an an in The studied polygon , within an abandoned meander on the river’s floodplain

(b) (b), (b), with

160 km south of the Laptev Sea coastline in the vicinity of the Anabar

1 2 Lowland

and 160 km south of the Laptev Sea coastline in the vicinity of the An- Surface elevation and thaw depth relative to the water level in the polygon hoto: 2007 August U. Herzschuh, of of the study area.

(a) (a) and (a) (a) . (P Siberian

Location is sparsely distributed throughout the area 1: North Location of the study area. The studied polygon (07-SA-LY) is located south of the The 07-SA-LY polygon was divided into a 12 m (A–L) by 13 m (1–13) grid of square

is sparsely distributed throughout the area (d) and t

community ,

ure Larix moss River Larix Fig Taymyr Peninsula Fig. 2. metre plots. A surfacegrid transect along from line which G. allpond three profiles along were the taken, surface was transect positioned in (Transect the G), illustrating the di thawing depth below thehighly rims compressed, in being contrast reduced from toground 54 surface conditions relative to beneath to 27 cm the therelative during water pond. to level sampling.) (Note: the in water the Core level pond. C in was the pond. Fig. 1. Taymyr Peninsula abar River North Siberian Lowland (c) a shrub-moss community (Photo: U. Herzschuh, August 2007).

6 1 2 3 4 5

48 ore C.

Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion PaperC |

trees (after Wolter, 2010). Larix C) and granulometrical characteristics of 13 4112 4111 C) and granulometrical characteristics of Core C. 13 δ Organic matter (TOC, TOC/TN, δ 4:

Organic matter (TOC, TOC/TN, Distribution of plant taxa presented in vegetation abundance/cover classes (after Braun- Figure Fig. 4. Blanquet, 1964) represented by circleslevel and in related the to pond). the Double elevation circles (in indicate cm, the relative locations to of the water Fig. 3.

2 3 1

– 49 ) and C. Robust end members members from the - members members (EM1 – Core Core

Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | A, B and

. ) of σ erent 2 ff

± sections

from Scorpidium scorpioides 4114 4113 member modelling for samples – End is abundant as species of the Amblystegiaceae in Subunits 2.1 and 2.2. member member modelling versions. The blue dotted line is the range of confidence (± 2σ) of the 5: -

The moss analyses revealed a dominance of Amblystegiaceae in Core C. The di End-member modelling for samples from sections A, B and Core C. Robust end-member Figure member scores give the proportion of variance explained by the robust end the residual member (RM) for each time slice. The solid grey lines are all end 16 end EM1.

species of this family varyMeesia along triquetra the units with a recent dominance of Fig. 6. scores give the proportionresidual of member (RM) variance for explained16 each by end-member time the modelling slice. robust versions. The end-members The solid (EM1) blue grey dotted lines and are line the all is end-members the from range the of confidence ( Fig. 5. the EM1. 6 7 4 5 1 2 3 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

is is 52 core core from

Unit 2

20 cm

while and 22

the diatom assemblage

with Unit 1, in mainly mainly

abundant abundant between

are correlates 4116 4115 the important species ) from Core C. Geumannomyces and Four Four ecological sections showing Pollen percentage plot showing the important palynomorphs and non-palynomorphs 8: Four ecological sections showing the important species in the diatom assemblage from

. ore ore C. The occurrence of epiphytic diatoms Botryococcus C dominated by benthic diatoms. Planktonic diatoms depth Figure Fig. 8. Core C. Thedominated occurrence by of benthic epiphytic diatoms.depth. Planktonic diatoms diatoms correlates are mainly abundant with between 22 Unit and 1, 20 cm while core Unit 2 is Fig. 7. (

4 5 6 2 3 1 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

, 54 tly

, , 53 the cm not

ere ere ), but were w permanen

Botryococcus

a

and and 19.5 Hamatocaulis Hamatocaulis Botryococcus

member, member, pollen ), but - Hamatocaulis ver- of of the sample. (For the two moss species

(MeeTri), (MeeTri), . Other parameters were )

saturated to palynomorph palynomorph - - while position palynomorphs. palynomorphs. The EM1, (MeeTri), - non the samples at 21.5

the length length and and non

the , and and

, Meesia Meesia triquetra Drepanocladus Drepanocladus exannulatus

Unit 1 and Unit 2 from from a water – excluding Drepanocladus exannulatus ( ore ore C and the non-palynomorph C member (EM1) and the residual member (RM) -

in Unit 1 and Unit 2, (ScoSco), Meesia triquetra

; DreExa A1) ranging ranging

with

Alnus fruticosa , le 4118 4117 ; DreExa – labelled labelled ore ore C)

C Alnus fruticosa (ScoSco), calculated calculated robust end scores of the diatom community ( important important species of moss, pollen

on plot Scorpidium scorpioides Drepanocladus cossonii by by the

– n data data

(HamVer), (HamVer), the palynomorph

NMDS overlai

9: ,

)

Drepanocladus cossonii igure indicate indicate the boundaries between abbreviations of diatom species of diatom see Tab abbreviations F length together with RM, the mosses vernicosus divide the diatom spectra into our assumed units tested (DreCos significant. The sample

Scorpidium scorpioides 1 2 3 4 5 6 7 8 9 data data Summary Summary plot of important indicator records. The variations in end

10 (HamVer), the palynomorph Summary plot of important indicator records. The variations in end-member, pollen and 10: the local hydrology in plot G8 (

NMDS plot of the diatom community (excluding the samples at 21.5 and 19.5 cm length) filled location.

- ure Fig and diatom reflect water

diatom data indicate thereflect boundaries the local between hydrology Unit inwater-filled plot 1 location. G8 and (Core Unit C) ranging 2, from while a the water-saturated to two a moss permanently species Fig. 10. overlain by the calculatedwith robust end-member data (EM1) on andthe important the mosses residual species member of (RM) moss, together pollen and non-palynomorphs. The EM1, the RM, Fig. 9. nicosus divide the diatom spectratested into (DreCos our – assumed units (Unit 1 and Unit 2). Other parameters were not significant. The sample(For abbreviations scores of labelled diatom species within see Core Table A1.) C the length position of the sample.

5 6 3 4 1 2

, 56 xis A clearly clearly the two

Scorpidium Scorpidium because the

Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | while . Axis 1 Larix Carex polygon

gradient. gradient. Thus LY -

taxa on the rim,

SA - depth 07 . The overlaid environmental factors s the Scorpidium scorpioides distribution of the vegetation along rim

the . The comprises the main nd a correlate with taxa above the water surface pond and ).

. ected plant communities on the rim and in the ff only set

, 4120 4119 in the pond between between

the surface vegetation from

Meesia triquetra water water for

ects the vegetation. The distribution of the vegetation along ff under the available data

are are distributed istribution istribution of the vegetation along a water from grows grows NMDS plot

A1: species

depth depth within the pond affects the vegetation

Figure shows the d scorpioides Carex active layer (al) and elevation (elev) water 2 is not clear

Presentation showing vegetation cover during stable (Unit 1) and unstable (Unit 2) NMDS plot for the surface vegetation from the 07-SA-LY polygon. Axis 1 clearly shows

3 4 5 6 7 8 9 1 2 Fig. A1. grows under water inspecies the are pond and distributed comprisesactive between layer the the (al) main and pond taxa elevationthe and on (elev) water the only the depth rim, correlate within rims. with the whileAxis The pond taxa 2 the a is above overlaid two not the environmental clear water from factors surface the because available data set. the distribution of the vegetation along a water depth gradient. Thus the water-saturated depression (with Fig. 11. stages. For Unit 1 we detected a shrub-tussock tundra with scattered occurrences of while Unit 2 had a high proportion of sand which a Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper |

57

58 . The ter ter level. Scorpidium 2012)

, especially , metric metric characteristics lo (after (after Schilling A and B. The granulometric

s

(after Schilling 2012). The constant section

conditions conditions with fluctuating wa

from Meesia Meesia triquetra al taxa were analyzed in this section , and e 4121 4122 were not measured. were

, transition

s Meesia triquetra ection ection B. The figure does not include the complete moss S , and to 6.9 cm

size distribution) represent -

for cm cm Amblystegiacea ain Calliergon giganteum 9.2

, , Meesia B

several of of

represents transitional conditions with fluctuating water level. only Section Moss spectrum

as presence Summary Summary plot of organic matter (TOC, TOC/TN) and granu

for Meesia A3:

Summary plot of organic matter (TOC, TOC/TN) and granulometric characteristics A2: Moss spectrum for Section B. The figure does not include the complete moss spectrum

member scores and gr - Figure spectrum Scorpidium scorpioides constant Figure (end parameters

2 3 4 5 6 1 presence of scorpioides Calliergon giganteum as only several Amblystegiaceae taxa were analyzed in this section, especially Fig. A3. Fig. A2. (end-member scores andparameters grain-size for distribution) Section B from 9.2 cm sections to 6.9 A cm and were not B. measured. The granulometric

4 5 1 2 3

59 from from this section

s Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | moss community to a

rim - and Carex

from a typical polygon

conditions.

only becoming established in the uppermost 4124 4123 wetter ection ection A. Only the surface and bottom sample S

was was recognized

for Larix gmelinii n inversion A . Moss spectrum A4:

Results of the macrofossil analysis for Section A showing a dominance of Moss spectrum for Section A. Only the surface and bottom samples from this section analysed in the lowermost samples with Figure were for with a preference community

samples from 4.8 cm to the surface. Fig. A5. Dryas Fig. A4. were analysed. Ana inversion community was with recognized a preference from for wetter a conditions. typical polygonrim moss community to

4 5 1 2 3 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | leaves in the uppermost samples is Larix 4125 . The peak of Andromeda polifolia taxa and The macrofossil spectrum for Section B showing wetter vegetation with a dominance Carex Fig. A6. of due to the presence of trees in the vicinity of the Section B sampling location (see Fig. 3).