A sediment core from Lake Veetka, southeast Estonia, 1077 cm in length and covering 10,500 calibrated years, was examined using loss-on-ignition, grain-size distribution and AMS 14C dating to ...reconstruct depositional dynamics. The studied core, recovered from the northern part of the lake, shows a cyclic pattern of organic and mineral matter concentration with cycle durations of 100-400 years. Cyclicity is displayed better in sediments laid down between 9,200 and 5,600 cal BP. Within two time windows (5,600-5,100 cal BP and from 1,200 cal BP to the present), sediment composition changed drastically on account of a high and fluctuating mineral matter content, obviously driven by different factors. Little Ice Age cooling is characterised by the highest proportion of mineral matter, and the Medieval Warm Period is typified by high organic matter content. The cyclic change of organic and mineral matter has been related to climate dynamics, most likely an alternation of wet and dry conditions, changes in the water level of the lake and differences in bioproduction
Current land use and climate change pose a threat to the continued provision of ecosystem services expected from terrestrial land cover. Studies on past land-cover responses to such changes provide ...valuable information for future decisions. The hemiboreal zone, situated between temperate and boreal biomes, is a natural sensitivity hotspot for land cover change: it contains a continuous distribution limit of several temperate (Quercus robur, Tilia cordata, Fraxinus excelsior, Ulmus glabra, etc.) and some boreal (e.g. Picea abies) tree species. High resolution pollen data from three lakes in South Estonia, a hemiboreal zone in Northern Europe, was used to reconstruct the climate-driven dynamics of vegetation composition, anthropogenic deforestation, species-specific responses to climate cycles, and plant related environmental variables during the Holocene at a local and regional scale. The Landscape Reconstruction Algorithm (LRA) was used to reconstruct the vegetation composition, the Ellenberg Indicator Values for environmental reconstructions, and the Wavelet analysis for detecting cyclic patterns. The major land cover and environmental changes are in good accordance with the climate-based formal tripartite subdivision of the Holocene: a quick succession of tundra, boreal, and nemoral biomes during the Early Holocene, a dominance of temperate, broad-leaved forests during the Middle Holocene, and an expansion of mixed boreal forests and anthropogenic deforestation during the Late Holocene. Several episodes of compositional turnover ranging from a century (e.g., the transition from wet to dry tundra) to several millennia (e.g., the replacement of the temperate deciduous forests with boreal mixed forests) were identified. Our results show that local community changes have a shorter duration than the regional ones. The introduction of slash-and-burn agriculture caused abrupt forest composition changes at a local scale, promoting early successional tree species, even prior to the establishment of a permanently open cultural landscape. The only late successional tree species favoured by slash-and-burn cultivation was Picea abies. However, the application of more permanent cultivation strategies reduced its representation considerably. The determined cyclic changes in the proportions of tree taxa show, that most late successional trees exhibit high frequency (ca 200–400 year) cyclicity, probably reflecting the stand scale regeneration processes. The observed 1600 ± 200 and 1200 ± 200 year cycle changes in the occurrences of Quercus robur, Ulmus glabra and U. laevis, and Picea abies have a possible connection with a 1500 ± 500 year Bond cycle. Most of the tested tree taxa also had a statistically significant correlation with the ca 2200–2500 year Bray solar forcing cycle.
•A succession of 4 biomes and the Late Holocene distinct deforestation was recorded.•Compositional turnover rates of vegetation range from a century to several millennia.•Local community changes have higher variation and shorter duration than regional.•Tree taxa occurrence is affected by 1500 (Bond) and 2200 (Bray) year climate cycles.•Pollen-based Ellenberg Indicator Values reflect well natural environmental conditions.
Pollen records from Lake Prossa, located in the Saadjärv Drumlin Field, indicate rather homogeneous pollen spectra in the pre-Allerød period and a thick sediment sequence suggesting high input of ...mineral matter and erosion. This period is characterized by pioneer vegetation with dwarf-shrubs. At the beginning of the Allerød, Salix, Artemisia and redeposited temperate and thermophilous taxa prevailed in pollen spectra, referring to shrub tundra conditions, followed later by Betula and Pinus(?) arrival. Silt with organic debris deposited. Vegetational set-back and tundra plant species with scattered birches and silty deposits containing abundantly Drepanocladus fragments characterize the Younger Dryas stadial. The sedimentation rate decreased markedly and was followed by a hiatus at the beginning of the Holocene. The AMS 14C dates, and microfossil and sedimentological data show that the ice front receded and stratified sediments started to deposit about 14 200–14 300 cal yr BP, permitting specification of poorly constrained ice recession chronology in central Estonia.
The Tallinn area was recovered from the Weichselian ice sheet not later than 13 ;000–12 ;800 ;cal ;yr ;BP but remained for ca 1500 years under the waters of the Baltic Ice Lake (BIL). The highest ...parts of Tallinn emerged from the BIL after its drainage about 11 ;600 ;cal ;yr ;BP. At the beginning of the Yoldia Sea stage the present city area was submerged by sea water, except for the highest parts of Viimsi, Lasnamäe and Nõmme. At the end of the Yoldia Sea stage the Ülemiste, Pääsküla and Männiku basins isolated from the sea. During the Ancylus Lake transgression about 10 ;300 ;cal ;yr ;BP the highest coastline at 34–36 ;m ;a.s.l. broadly outlined the klint escarpment. The Litorina Sea transgressional coastline at 7800–7600 ;cal ;yr ;BP and beach formations at 21–22 ;m ;a.s.l. are less developed than the Ancylus ones and often covered by aeolian deposits. Toompea arched north as a cape in the Litorina Sea and the previous Viimsi Island joined with the mainland. During the Limnea Sea stage (4400 ;cal ;yr ;BP up to the present, the highest coastline at ca ;12 ;m ;a.s.l.) land increased mostly at the back of Kakumäe and Kopli bays. The Kakumäe Peninsula obtained its outline about 2800 years ago, the Kopli Peninsula ca 1000 years later. The Paljassaar Peninsula was the latest to be formed ca 100 years ago. The attached palaeogeographical maps display shore displacement during the different stages of the Baltic Sea in the vicinity of Tallinn.
The marine-freshwater environmental transition, i.e. basin isolation from the Limnea Sea, has been identified in two short sediment cores with respect to their diatom composition, loss-on-ignition ...and magnetic susceptibility content. The isolation level of the basins was dated by accelerator mass spectrometry radiocarbon measurements. The basins are situated on the southern coast of the Gulf of Finland between altitudes 5.5 and 3.9 m above sea level. The Lohja basin became isolated from the sea around 2300 cal yr BP and Käsmu basin around 1800 cal yr BP as a result of glacio-isostatic uplift. The total land upheaval rate that has been 2.6 mm yr –1 since 2500 cal yr BP has currently decreased to 2.0 mm yr –1. We present a GIS-based 3D palaeogeographic reconstruction of the palaeocoastline changes in northern Estonia for two peninsulas, Pärispea and Käsmu, as well as compose a shoreline displacement curve for the study area, which is a compilation of previous and ongoing investigations.
Palynological, chronological and sedimentological studies were performed at three Holocene sediment profiles from south-eastern Estonia (lakes Plaani, Verijärv and Lasva), which form a transect from ...the central part of the Haanja Heights across the northern slope to the ancient buried valley at its foot. The aim of the study was to utilize pollen records to investigate vegetation and land-use dynamics. The pollen stratigraphy of Verijärv starts
ca. 10 500
cal
BP, Lasva – 8400
cal
BP and Plaani – 6300
cal
BP. The early arrival of
Picea,
Ulmus and
Quercus, long-lasting broad-leaved trees owing to the presence of suitable habitats in the mosaic landscape and delayed human interference are outlined. Limited crop growing started in the Later Bronze Age with
Triticum and
Hordeum cultivation, but became the primary source of subsistence in the Late Iron Age. Changes in agricultural practices, population densities, historical and political events affected agrarian activities and are registered in pollen diagrams as declines in anthropogenic indicators.
Secale cultivation was blooming between 1300 and 200
cal
BP, but since AD 1860–1870 considerably decreased as a result of changes in land ownership and the start of potato cultivation.
Pollen-based quantitative vegetation reconstructions using multiple sedimentary basins from the same area, along with their quantified relevant pollen source areas, are a powerful means to study how ...long-term human impact has affected vegetation and shaped the currently protected heritage landscapes at different spatial scales. Our study presents the outcome of a palynological investigation in Karula Upland, south Estonia, for the last 6500 years. Centennial-resolution pollen records from one large (175 ha) and three small (5 ha) lakes, and one small bog (0.1 ha) were used to reconstruct the vegetation at different spatial scales using the Landscape Reconstruction Algorithm. The results are discussed in combination with archaeological sites and historical knowledge.
The first signs of small-scale forest clearings connected to local human settlements are already visible in the Middle Stone Age (3100–4100 BCE). The first finds of cereal pollen (2500 BCE) from Lake Ähijärv suggest that grain crops were introduced to south Estonia during the Late Stone Age. The evidence of local crop farming in Karula is traceable since the Bronze Age. The widespread practice of slash-and-burn agriculture led to a major shift in land-cover with replacement of old-growth forests with the early-successional birch, occupying long-term fallows, during Late Bronze Age and Early Iron Age (700–250 BCE). A notable regression in farming is visible during the second part of the Early Iron Age (100–600 CE), with the most prominent change taking place around 500 CE, roughly coinciding with the 6th century Northern Hemisphere climate cooling and Migration Period. Permanent fields gained importance alongside slash-and-burn cultivation, during the Late Iron Age, ca 600–700 CE, shifting the vegetation composition towards more open land-cover. The ∼50 % open mosaic land-cover of the heritage landscape, protected today in Karula Upland, was formed during the Late Iron Age.
The current study shows that sedimentary basins as close as ca 2 km from each other sometimes tell different stories, highlighting the need to quantify the size of the pollen source area to combine successfully archaeological, historical, and palynological evidence. Quantitative pollen-based vegetation reconstructions provide an environmental context for known, and possibly unknown, archaeological evidence within the pollen source area.
•Multidisciplinary approach provides reconstruction of human habitation history.•Pollen-based land-cover reconstruction defines area for archaeological finds.•The arrival of the Corded Ware culture in the Stone Age is evidenced by cereal pollen.•Slash-and-burn practice is indicated by charcoal and early-successional trees.•Land-cover reached the basic structure similar to that of today during the Iron Age.
This paper discusses a complete record of vegetation history since the Bølling (GI-1e) warming (14,500calyrBP) up to the Holocene in Latvia. To date, this is the only complete record of such age in ...the eastern Baltic area and the northernmost area for which Bølling records are present. Combining pollen evidence, pollen accumulation rates (PAR) and plant macrofossil data, we assess the local and regional vegetation development, and we attempt to separate the true Lateglacial vegetation signal by removing the obviously redeposited thermophilous pollen; however, we remove not only their signal, we discuss the possibilities of separating the redeposition signal of the so-called “local Lateglacial trees”, pine and birch, by looking at their corrosion and degradation. The results show that the Bølling warming in the eastern Baltic area was a treeless tundra community consisting of the shrubs Betula nana, Dryas octopetala and Salix polaris. The Older Dryas cold spell is clearly recognised as a decline in the total concentration of plant macrofossils and PARs at between 14,200 and 13,500calyrBP. At 13,460calyrBP, the B. nana macrofossils disappear, and tree birch (Betula sect. Albae) appears, marking the start of tree birch forest. The presence of pine forest is confirmed by a variety of macrofossils, including bark, wood, needles and seeds, since 13,400calyrBP, at the same time at which pine stomata are found. The first identified pine stomata finds are associated with a Pinus PAR over 3000grainscm−2yr−1 and pine macrofossil finds with a Pinus PAR over 4000grainscm−2yr−1. During the warmest period of the GI-1a (Allerød) at 13,000–12,700calyrBP, a pine forest with deciduous trees (birch –Betula pendula and aspen –Populus tremula) developed in the study area. The Younger Dryas (GS-1) cooling strongly affected the floral composition in eastern Latvia. The PAR of the tree taxa declined abruptly from a maximum value at 12,700 to below 1000grainscm−2yr−1 at 12,600calyrBP. The response time for the pine forest to collapse was 100 years according to the PAR data. Pine macrofossils disappear simultaneously with the pollen signal at 12,600calyrBP, yet occasional Pinus stomata are recorded throughout the Younger Dryas (GS-1). The landscape was treeless shrub tundra again, with D. octopetala, S. polaris, B. nana and Juniperus present. Picea is introduced in the region within the cold Younger Dryas and is represented by stomata (12,400–12,200calyrBP), needles, seeds and wood (since 12,050calyrBP up to the Holocene). The Pleistocene/Holocene boundary at 11,650calyrBP is marked by changes both in vegetation composition and sediment type. The organic rich gyttja accumulated instead of silts and clays, and the start of the Holocene warm period permitted forest re-expansion in eastern Latvia.
► Unambiguous vegetation record since Bølling warming from NE Europe since 14,550calyrBP. ► Multiproxy evidence of regional and local vegetation responses to Lateglacial climate. ► New method applying corroded pollen and macrofossil data for Lateglacial vegetation signal. ► Evidence of rapid establishment of Lateglacial birch, pine, spruce and aspen forests. ► Climate sensitivity of terrestrial vs. aquatic evidence of NE European biota.
Relative sea level (RSL) changes and the palaeogeography of a Neolithic hunter-fisher-gatherer settlement site on the former shore of the Gulf of Finland in the city centre of Tallinn were ...reconstructed by implementing GIS in landscape modelling based on archaeological, sedimentary and shore displacement data. AMS radiocarbon dating of mammal bones from the cultural layer suggests the existence of the hunter-fisher-gatherer settlement around 5.1–4.8 cal. ka BP on a seaward inclining sandy beach of Tallinn palaeo-bay c. 100 m from the Litorina Sea shoreline and at about 2.4 m above the coeval sea level. The shoreline passed the study site at about 5.8 cal. ka BP and retreated towards northeast with an average speed of 13 m per century, while the RSL lowered by c. 2.5 mm annually. Combining radiocarbon dates of terrestrial and marine mammal bones from the Neolithic cultural layer, a marine reservoir effect of 350 14C years for the brackish-water Baltic Sea was calculated. By using high-resolution archaeological data in combination with RSL and other geological proxies, we demonstrate new possibilities to reconstruct the palaeoenvironment of deeply buried coastal settlement sites and to predict a possible continuation of the cultural layer in heavily built-up areas.
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