Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish - Karelian inland area

This thesis discusses the prehistoric human disturbance during the Holocene by means of case studies using detailed high-resolution pollen analysis from lake sediment. The four lakes studied are situated between 61o 40' and 61o 50' latitudes in the Finnish Karelian inland area and vary between 2.4 and 28.8 ha in size. The existence of Early Metal Age population was one important question. Another study question concerned the development of grazing, and the relationship between slash-and-burn cultivation and permanent field cultivation. The results were presented as pollen percentages and pollen concentrations (grains cm 3). Accumulation values (grains cm 2 yr 1) were calculated for Lake Nautajärvi and Lake Orijärvi sediment, where the sediment accumulation rate was precisely determined. Sediment properties were determined using loss-on-ignition (LOI) and magnetic susceptibility (k). Dating methods used include both conventional and AMS 14C determinations, paleomagnetic dating and varve choronology. The isolation of Lake Kirjavalampi on the northern shore of Lake Ladoga took place ca. 1460 1300 BC. The long sediment cores from Finland, Lake Kirkkolampi and Lake Orijärvi in southeastern Finland and Lake Nautajärvi in south central Finland all extended back to the Early Holocene and were isolated from the Baltic basin ca. 9600 BC, 8600 BC and 7675 BC, respectively. In the long sediment cores, the expansion of Alnus was visible between 7200 - 6840 BC. The spread of Tilia was dated in Lake Kirkkolampi to 6600 BC, in Lake Orijärvi to 5000 BC and at Lake Nautajärvi to 4600 BC. Picea is present locally in Lake Kirkkolampi from 4340 BC, in Lake Orijärvi from 6520 BC and in Lake Nautajärvi from 3500 BC onwards. The first modifications in the pollen data, apparently connected to anthropogenic impacts, were dated to the beginning of the Early Metal Period, 1880 1600 BC. Anthropogenic activity became clear in all the study sites by the end of the Early Metal Period, between 500 BC AD 300. According to Secale pollen, slash-and-burn cultivation was practised around the eastern study lakes from AD 300 600 onwards, and at the study site in central Finland from AD 880 onwards. The overall human impact, however, remained low in the studied sites until the Late Iron Age. Increasing human activity, including an increase in fire frequency was detected from AD 800 900 onwards in the study sites in eastern Finland. In Lake Kirkkolampi, this included cultivation on permanent fields, but in Lake Orijärvi, permanent field cultivation became visible as late as AD 1220, even when the macrofossil data demonstrated the onset of cultivation on permanent fields as early as the 7th century AD. On the northern shore of Lake Ladoga, local activity became visible from ca. AD 1260 onwards and at Lake Nautajärvi, sediment the local occupation was traceable from 1420 AD onwards. The highest values of Secale pollen were recorded both in Lake Orijärvi and Lake Kirjavalampi between ca. AD 1700 1900, and could be associated with the most intensive period of slash-and-burn from AD 1750 to 1850 in eastern Finland.Tutkimuksessa selvitettiin asutus- ja viljelyhistorian varhaisimpia vaiheita ja seurattiin niiden kehittymistä kohti nykyaikaa jääkauden jälkeisellä holoseeniajalla. Erityisenä mielenkiinnon kohteena oli ihmistoiminnan selvittäminen sisämaan huonosti tunnetulla ajanjaksolla nk. varhaismetallikaudella, joka vastaa rannikon pronssikautta, mutta ajoitetaan kuitenkin pitemmälle ajanjaksolle noin 1800 eKr. 300 jKr. Keskeisenä tutkimusmenetelmänä oli järven pohjasedimentistä tehtävä siitepölyanalyysi. Tutkimusaineisto koostui neljästä, pikkujärven pohjasedimentistä kairatusta pitkästä sedimenttisarjasta. Tutkitut järvet sijaitsevat sisämaassa 61o 40' sekä 61o 50' leveyspiirin välissä Keski- ja Itä-Suomessa sekä Laatokan pohjoisrannalla. Siitepölyanalyysissä havaittujen tapahtumien ajoituksiin käytettiin radiohiiliajoitusta, paleomagneettista ajoitusta sekä vuosilustokronologiaa. Keski- ja Itä-Suomessa sijaitsevat järvet ovat kuroutuneet Itämerestä 9600 7600 eKr., ja niiden pitkät sedimenttisarjat mahdollistavat kasvillisuudenkehityksen tarkastelun varhaiselta holoseenikaudelta lähtien. Laatokan pohjoispuolella sijaitseva lampi on kuroutunut Laatokasta itsenäiseksi pikkujärvekseen noin 1300 eKr. Ensimmäiset, todennäköisesti ihmisen aikaansaamat muutokset on nähtävissä varhaismetallikauden alusta 1880 1600 eKr., ja selkeytyvät varhaismetallikauden loppuun mennessä. Kaskiviljelyn alku ajoittui rukiin siitepölyjen esiintymisen perusteella 300 - 880 jKr. Yleispiirteissään ihmisen vaikutus säilyy vähäisenä myöhäisrautakauden alkuun noin 800 jKr. saakka, jonka jälkeen ihmistoiminta voimistuu, asutus kiinteytyy ja merkkejä peltoviljelystä ilmaantuu. Itäisissä tutkimuskohteissa tulen käyttö lisääntyy 800 900 jKr., voimaperäisin kaskiviljelykausi ajoittuu aikavälille 1700-1900 jKr

From Forest to a Farmland. Palaeoenvironmental Reconstruction of the Colonization of Western Uusimaa

According to the traditional hypothesis formulated on the basis of earlier archaeological and historical records, it was not until between the 12th and 14th centuries, when Swedes colonised the new areas in the northeastern side of the Baltic Sea. In order to investigate this hypothesis and the settlement history of Uusimaa, the pollen analytical results from altogether six continuous sediment cores from small lakes are presented. Former pollen analytical studies in the southern coastal areas provide important reference material.In the pollen data, after the isolation of the lakes, the earliest phase of land use extends from the Pre-Roman Iron Age (500 BC - AD 1) through the Early Roman Iron Age (AD 1 - 200) until the end of the Late Roman Iron Age (AD 200 - 400). This period of land use can be described as forest clearing associated in some places with sporadic, small-scale cultivation.Intensification of land-use practices is recorded from the beginning of the Migration Period (AD 400 -600). Among the six study sites, there is evidence for continuous rye cultivation from AD 390 - AD 440 onwards on the large maritime island of Orslandet (Ingå) and also in the more coastal environment in Prästkulla (Ekenäs in Raseborg).A fully agrarian landscape with permanent settlements, cultivated fields, and pastures becomes observable in the southern coastal areas gradually. Among the six studied cultural sites, this is first demonstrated on the archipelagic island Orslandet from as early as AD 670 onwards. In most study sites, there is evidence for permanent settlement and a fully agrarian landscape from AD 940 - 1100 onwards

Stone Age–Early Metal Period transition in the southern Finnish Lake District: incipient forest grazing and temporary burning practices

Peer reviewe

Neolithic land use in the Northern Boreal Zone : High-resolution multiproxy analyses from Lake Huhdasjärvi, south-eastern Finland

Two high-resolution pollen and charcoal analyses were constructed from sediments obtained from a small bay in eastern Finland in order to gain information on human activity during the Neolithic Stone Age, 5200-1800 BC. We used measurements of loss on ignition (LOI), magnetic susceptibility, and geochemical analyses to describe the sedimentological characteristics. Palaeomagnetic dating and measurements of Cs-137 activity were supported by C14 datings. The analyses revealed human activity between 4400 and 3200 BC, which is synchronous with archaeological cultures defined through different stages of Comb Ware pottery types and Middle Neolithic pottery types with asbestos as a primary temper. Direct evidence of Hordeum cultivation was dated to 4040-3930 cal BC. According to the pollen data, more significant effort was put into the production of fibres from hemp than the actual cultivation of food.Peer reviewe

Pollen Evidence in Exploring Settlement Dynamics, Land Use, and Subsistence Strategies in the Aland Islands through Multiproxy Analyses from the Lake Dalkarby Trask Sediment Record

In this study, which presents pollen, charcoal, and 'soot'-particle records from a lacustrine sediment core, the development of the cultural landscape around Lake Dalkarby trask on the Aland Islands in Finland is scrutinised and discussed within a broad temporal setting in order to clarify the long-term interplay between the environment and human activities in this part of the archipelago. Special emphasis is given to the transition period from the Late Iron Age to medieval times due to the dominating humanistic discourse on the settlement dynamics in this region, as in the Aland archipelago in general, arguing for an approximately 150-years-long hiatus in habitation between these two periods, from AD 1050 to 1200. Our results do not support the hiatus theories but show a long and continuous history of the utilisation of land and forest resources starting from prehistoric times. The forests were first cleared with fire for slash-and-burn cultivation. Thereafter, structural diversity in the landscape started to increase. By 1240, the pollen data portrays a picture of a developed agrarian community with a subsistence economy based on arable farming and animal husbandry in which hemp seems to play a substantial part

‘The Color of the Grave is Green’ – Moss and Juniper in Early Medieval Graves at Toppolanmäki, Finland

Two graves, initially discovered in the 1930s, were reopened and examined in 2017 and 2018 at the Early Medieval cemetery of Toppolanmäki, Finland. Soil samples taken from the graves were sampled for macrofossils, pollen and microfauna. Pollen and spore analysis provided possible evidence for the use of mosses and juniper branches in the graves. Also, moss-indicating microfauna (Euglypha spp.) was detected. At Toppolanmäki, mosses were used in both coffins and earth burials. The clubmoss found in the latter could even indicate the presence of a woven carpet or mattress in the grave pit. The use of juniper, on the other hand, could indicate ritual continuation from the Iron Age as it is a common find in older cemeteries. It is also possible that the early medieval environment around the site was characterised by dry meadows and juniper bushes at the time of the burial, and even that one of the burials took place in early summer. The study highlights the research potential of graves that have been excavated decades ago and presents a new biological indicator of the use of moss in burials: the testate amoeba Euglypha.</p

Human-environment interaction during the Holocene along the shoreline of the Ancient Lake Ladoga: A case study based on palaeoecological and archaeological material from the Karelian Isthmus, Russia

This paper presents the results of pollen, diatom, charcoal, and sediment analyses from Lake Bol'shoye Zavetnoye, situated between the Gulf of Finland and Lake Ladoga on the Karelian Isthmus, north-western Russia. The main goal is to contribute to the discussion of Neolithic land use in north-eastern Europe. The article aims to answer questions related to Stone Age hunter-gatherer economy, ecology, and anthropogenic environmental impact through a comprehensive combination of multiple types of palaeoecological data and archaeological material. According to diatom data, Lake Bol'shoye Zavetnoye was influenced by the water level oscillations of Ancient Lake Ladoga during much of the Holocene. Intensified human activity and prolonged human occupation become visible in the Lake Bol'shoye Zavetnoye pollen data between 4480 BC and 3250 BC. During the final centuries of the Stone Age, a new phase of land use began, as several anthropogenic indicators, such asTriticum, Cannabis, andPlantago lanceolataappear in the pollen data and a decrease inPinusvalues is recorded. In general, the results indicate that socio-cultural transformations could have taken place already from the mid-5th millennium BC onwards, including new ways of utilizing the environment, perhaps also in the field of subsistence, even though the livelihood was based on foraging throughout the period.Peer reviewe

The Late Medieval Church and Graveyard at Ii Hamina, Northern Ostrobothnia, Finland – Pollen and macro remains from graves

The historical Ostrobothnian (Finland) burial tradition is poorly known, particularly when discussed from the environmental archaeological viewpoint. This article examines Late Medieval burial methods in Ii Hamina village using both micro- and macrofossil analyses incorporated into archaeological work. This research provides information on the continuity of burial methods that were sustained through the medieval period and into modern times. Burial tradition patterns in the Northern Ostrobothnia region exhibit widely recognised characteristics, but also contain some local features

Buried in water, burdened by nature-Resilience carried the Iron Age people through Fimbulvinter

Levanluhta is a unique archaeological site with the remains of nearly a hundred Iron Age individuals found from a water burial in Ostrobothnia, Finland. The strongest climatic downturn of the Common Era, resembling the great Fimbulvinter in Norse mythology, hit these people during the 6th century AD. This study establishes chronological, dietary, and livelihood synthesis on this population based on stable carbon and nitrogen isotopic and radiocarbon analyses on human remains, supported by multidisciplinary evidence. Extraordinarily broad stable isotopic distribution is observed, indicating three subgroups with distinct dietary habits spanning four centuries. This emphasizes the versatile livelihoods practiced at this boundary of marine, freshwater, and terrestrial ecosystems. While the impact of the prolonged cold darkness of the 6th century was devastating for European communities relying on cultivation, the broad range of livelihoods provided resilience for the Levanluhta people to overcome the abrupt climatic decline.Peer reviewe

Holocene changes in vegetation composition in northern Europe: why quantitative pollen-based vegetation reconstructions matter

International audienceWe present pollen-based reconstructions of the spatio-temporal dynamics of northern European regional vegetation abundance through the Holocene. We apply the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model using fossil pollen records from eighteen sites within five modern biomes in the region. The eighteen sites are classified into four time-trajectory types on the basis of principal components analysis of both the REVEALS-based vegetation estimates (RVs) and the pollen percentage (PPs). The four trajectory types are more clearly separated for RVs than PPs. Further, the timing of major Holocene shifts, rates of compositional change, and diversity indices (turnover and evenness) differ between RVs and PPs. The differences are due to the reduction by REVEALS of biases in fossil pollen assemblages caused by different basin size, and inter-taxonomic differences in pollen productivity and dispersal properties. For example, in comparison to the PPs, the RVs show an earlier increase in Corylus and Ulmus in the early-Holocene and a more pronounced increase in grassland and deforested areas since the mid-Holocene. The results suggest that the influence of deforestation and agricultural activities on plant composition and abundance from Neolithic times was stronger than previously inferred from PPs. Relative to PPs, RVs show a more rapid compositional change, a largest decrease in turnover, and less variable evenness in most of northern Europe since 5200 cal yr BP. All these changes are primarily related to the strong impact of human activities on the vegetation. This study demonstrates that RV-based estimates of diversity indices, timing of shifts, and rates of change in reconstructed vegetation provide new insights into the timing and magnitude of major humandisturbance on Holocene regional vegetation, features that are critical in the assessment of humanimpact on vegetation, land-cover, biodiversity, and climate in the past