1200433
research-article2023

HOL0010.1177/09596836231200433The HoloceneVinogradova et al.

Research Paper

3000 Years of past regional and local
land-use and land-cover change in thesoutheastern Swedish coastal area:
Early human-induced increases inlandscape openness as a potential nutrient
source to the Baltic Sea coastal waters

The Holocene
2024, Vol. 34(1) 56­–73© The Author(s) 2023
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https://doi.org/10.1177/09596836231200433
DOI:
10.1177/09596836231200433
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Olena Vinogradova,1 Marie-José Gaillard,2 Elinor Andrén,1Veronica Palm,3,4 Johan Rönnby,4 Martin Dahl,1 Elisabeth Almgren,5
Jon Karlsson,6 Anne Birgitte Nielsen,7 Christine Åkesson7,8
and Thomas Andrén1

Abstract
Reconstructions of past land use and related land-cover changes at local and regional scales are needed to evaluate the potential long-term impacts of land useon the coastal waters of the Baltic Sea. In this purpose, we selected the Gamleby area at the Swedish Baltic Sea coast for a case study. We use a new, highresolution pollen record from a small lake (Lillsjön) located 3.6 km NNW of the bay Gamlebyviken and detailed analysis of the available archeological data toreconstruct local land-use changes over the last 3000 years. To estimate land-cover change at local (2–3 km radius area) and regional (50 km radius area) scales
we use four additional, published pollen records from two small and two large lakes (25–70 km S of Lillsjön) and the Landscape Reconstruction Algorithm, apollen-vegetation modeling scheme. Results show that regional and local (small lakes Lillsjön and Hyttegöl) land-cover changes are comparable over the last
1500 years (Late Iron Age to present), and that landscape openness was much larger locally than regionally (difference of 20–40% cover over the last 500 years).
The periods of largest potential impacts on the Gamlebyviken Bay from regional and local land use are 200–950 CE (Late Iron Age) and 1450 CE to present,
and of lowest potential impacts 950–1450 CE. The question on whether the large landscape openness 1150–50 BCE and significant afforestation 50 BCE–200
CE reconstructed for Lillsjön’s area are characteristic of the Gamlebyviken region will require additional pollen records in the catchment area.

Keywords
Archeological data, Gamlebyviken, Landscape Reconstruction Algorithm, Late Holocene, pollen analysis, REVEALS and LOVE models
Received 21 April 2023; revised manuscript accepted 24 July 2023

Introduction
Current eutrophication of the Baltic Sea coastal waters caused
both by point sources and diffuse input from mainly agriculturalactivities in its catchment is a recognized environmental problem
leading to extensive areas with low oxygen content (Carstensen
et al., 2014; Conley et al., 2011; HELCOM, 2018). Eutrophication of the Baltic Sea is amplified by its semi-enclosed basin configuration and the extensive freshwater runoff from the densely
populated drainage area with intense agriculture (e.g. Carstensen
and Conley, 2019; Snoeijs-Leijonmalm and Andrén, 2017). It isan almost isolated sea with a maximum depth of 459 m and a very
narrow connection to the North Sea resulting in a long water-residence time of ca. 30–40 years (Leppäranta and Myrberg, 2009).
The role played by long-term land-use and climate changes in the
eutrophication of the Baltic Sea and spread of hypoxia is still not
fully understood (Kabel et al., 2012; Norbäck Ivarsson et al.,2019; Schimanke et al., 2012; Zillén et al., 2008). Large scaleland-use changes in the watershed have been suggested to be thesource of excess nutrient input needed to develop deep water
hypoxia in the open Baltic Sea already during medieval times(Åkesson et al., 2015; Funkey et al., 2014; Zillén and Conley,1

S chool of Natural Sciences, Technology and Environmental Studies,
Södertörns University, Sweden
2
Department of Biology and Environmental Science, Linnaeus
University, Sweden
3
Västerviks Museum, Sweden
4
School of Historical and Contemporary Studies, Södertörns University,
Sweden5
Department of Earth Sciences, Uppsala University, Sweden
6
Department of Ecology and Environmental Science, Umeå University,
Sweden7
Department of Geology, Lund University, Sweden
8
School of Geography and Sustainable Development, St Andrews
University, UK
Corresponding authors:
Olena Vinogradova, School of Natural Sciences, Technology andEnvironmental Studies, Södertörns University, Alfred Nobels Allé 7
Flemingsberg, Huddinge 14189, Sweden.
Email: olena.vinogradova@sh.se
Marie-José Gaillard, Department of Biology and Environmental Science,
Linnaeus University, Stuvaregatan 4, Kalmar 39231, Sweden.
Email: marie-jose.gaillard-lemdahl@lnu.se

Vinogradova et al.

57

Figure 1. Location of the study area in (a) Scandinavia and (b) southeastern Sweden, and its geological characteristics. Of the five sites/lakes/
pollen records used in the application of the Landscape Reconstruction Algorithm (LRA), only Lillsjön is a new pollen record (this paper); theother four pollen records were published earlier (see Table 1). Mean center point = geometrical center of the four lakes (Lillsjön, Hyttegöl,
Tjursbosjön and Stärringen) centers. Spatial scale of the reconstructions of regional plant cover using the REVEALS model: 50 km radius areaaround, black circle = the mean center point, dark blue dashed circle = the center of lake Tjursbosjön, and light blue dashed circle = the centerof lake Storsjön. Spatial scale of the reconstructions of local plant cover using the LOVE model: 2–3 km radius area around the center of thesmall lakes (small black circles). Location of other studies mentioned in the text (map b): 1. Skåne, Ystad project (Berglund, 1991); 2. Småland,
Jönköping project (Berglund et al., 2002); 3. Eastern Småland (Bradshaw and Lindbladh, 2005); 4. Blekinge (Berglund et al., 2021). For details on
the LRA, and the REVEALS and LOVE models, see Methods and Supplemental Appendix 2, available online.

2010). Other authors argued that hypoxia is a natural feature of
the Baltic Sea system and is mainly controlled by climate (e.g.
Andrén et al., 2020; Bianchi et al., 2000; Kabel et al., 2012).
There is still limited knowledge on the extent and effect of humaninduced land transformation in the Baltic Sea coastal areas prior
to the industrial revolution (Jokinen et al., 2018; Ning et al.,2018). Based on paleoecological analyses of the sediment records
from a large lake and the Gåsfjärden Bay (SE Sweden), locatedca. 30 km apart, Ning et al. (2018) concluded that the onset ofhuman-induced eutrophication in the bay dates from the 19th century and is related to intensified land use as its main driver. Morestudies of this kind are necessary to understand all mechanisms
behind eutrophication of the Baltic Sea in a long-time perspective(Åkesson et al., 2015; Ning et al., 2018; Schimanke et al., 2012;
Zillén and Conley, 2010).
This study is part of a larger project with the aim to disentangle
the long-term role of human-induced processes from that of naturally driven ones and identify the significance of multiple stressors
as causes behind events of eutrophication and hypoxia of the Baltic Sea. Here, we focus on the Gamlebyviken Bay in southeastern
Sweden and its surroundings, which is a region rich in archeological findings from the Bronze Age and Iron Age in particular (Figures 1 and 2). We use a new pollen record from a small lake
(Lillsjön) located a few km from the Gamlebyviken Bay and four
additional published pollen records to reconstruct land-use andland-cover change at both local (2–3 km radius area) and regional(50 km radius area) scales for the last 3000 years. In this purpose,
we apply the indicator species approach (e.g. Gaillard, 2013) andthe Landscape Reconstruction Algorithm (LRA; Sugita, 2007a,

2007b), a modeling approach to estimate the percentage cover ofplants from fossil pollen assemblages. A combined interpretationof the pollen-based reconstructions and a survey of the archeological information around Lillsjön allows us to estimate past changes
in deforestation over space and time in the catchment of Gamlebyviken. The major aim of the study is to test the assumption that
periods of extensive and intensive exploitation of the land byhumans since the Bronze Age, both locally and regionally, led todeforestation and opening of the landscape of such a magnitude
that it could already have affected the Baltic Sea before the 19th
century (Ning et al., 2018), as suggested earlier by for example,
Zillén and Conley (2010) but not convincingly demonstrated so far
due to the lack of quantitative pollen-based land-cover reconstructions in the coastal regions for periods older than 1000 CE.

Study region and study sites
The study region (Figure 1) belongs to the hemiboreal vegetation
zone dominated by coniferous forest (Ahti et al., 1968) with widespread occurrence of deciduous trees, mainly Quercus, Betula, andPopulus (Rydin et al., 1999). It is today a mosaic rural landscapewith woodland and agricultural land in varying proportions. Quaternary deposits in the area are dominated by postglacial clay andglacial till, and bedrock consists mainly of quartzite and granite(geological map accessible at Geological Survey of Sweden(SGU), www.sgu.se, accessed 26 September 2023; Svenonius,
1914; Figure 1). The present temperatures and precipitations(average January, July and annual) are −2°C, 16°C, and 7°C, and37, 60, and 484 mm, respectively (Statistical Yearbook of Sweden,

58

The Holocene 34(1)Figure 2. Maps of archeological findings within an area of 4 km radius around the lake Lillsjön from the Stone Age until the 19th century. Notethat Storsjön II is not the large lake Storsjön used in the application of the Landscape Reconstruction Algorithm and shown in Figure 1.
(a) locations with findings from the Stone Age, some also including findings that can date from the Bronze Age; (b) locations with findings fromthe Bronze Age, of which a large number can also date from the Early Iron Age. (c) locations with findings from the Iron Age, of which a large
number can also date from the Bronze Age (see (b)). (d) locations with findings from Middle Ages to 1850 CE. 1–8 Farms known from written
sources since the 14th century that may have established already in the Iron Age: 1. Gursten, 2. Fästad, 3. Vida, 4. Langeharg/Nygård, 5. Valstad,6. Olserum, 7. Lapserum, 8. Dynestad. For details on dating, see Results.
Lill: Lillsjön; St II: Storsjön II; Dyn: Dynestadsjön.

2014). The main study site, Lillsjön, is located a few kilometers
north of Gamlebyviken within a landscape of coniferous andmixed woodland and agricultural land. Archeological remains are
numerous and testify on continuous human activities in the lake’s
surroundings during the study period (Figure 2). The lake Lillsjön(57°55.934′N, 16°23.342′E; altitude: 16 m a.s.l.; water depth:
2.2 m) is located ca. 3.6 km from the Gamlebyviken Bay and 4 km
from the town Gamleby (Figure 1). It is today a eutrophic lakewith a surface area of 0.16 km2 and a minor outlet to Lake Storsjön
II (Figure 2). A bog situated nearby is a potential source of humic
material to the lake. Further details on Lillsjön and four additionalsites for the application of the Landscape Reconstruction Algorithm (Figure 1; see Methods for details) are provided in Table 1.

Material and methods
Note that the Supplemental Appendices 1–3, available online
with related Tables and Figures that we are referring to in thefollowing sections are provided as Supplemental Material,
available online.

Lillsjön
Fieldwork, lithology, subsampling, and loss-on-ignition
The sediments of the lake Lillsjön were cored in February 2017using a 1-m-long Russian corer with a 1-m-long and 5-cm-diameter collecting chamber. The sampling site was selected in theVinogradova et al.

59

deepest part of the lake. Nine meters of sediments were extracted
as 1-m-long core sections in two parallel holes to secure overlap
between them. Lithology was described in the field and checkedin the laboratory after cleaning the sediment surface and before
subsampling. Sediment sections (2–3.5-cm-long) were taken atregular intervals along the core to be wet sieved and select material for 14C dating. Two 1-cm3 subsamples were collected every
5 cm at the same levels for pollen analysis and loss on ignition.
Loss on ignition was performed following Dean (1974). Sediment
samples were weighed three times, wet, after drying overnight at
105°C, and after burning in a furnace for 1 h 25 min at 550°C.

Dating and age-depth modeling14

Sixteen sediment subsamples for C dating were washed througha sieve (mesh size: 250 µm). Plant macrofossil remains and charcoal fragments were sorted under a binocular microscope. The
material was freeze-dried and submitted to the Laboratory of Ion
Beam Physics, ETH, Zürich, Switzerland for AMS 14C dating.
One freeze-dried bulk sediment sample from the deepest part ofthe sediment sequence was submitted to Beta Analytic, USA, foran estimate of the bottom sediments’ age. The age of the sedimentsurface was set to 2017 CE, the year of coring. All 14C dates were
calibrated using the IntCal20 calibration dataset (Reimer et al.,2020) with R ver. 4.2.0 (R Core Team, 2022). The age-depth
model was produced using the Bacon ver. 2.5.7 package (Blaauw
et al., 2022) with the following settings: accumulation mean 10,
accumulation shape 1.5, default section thickness 5 cm, memory
mean 0.5, and memory strength 10. Black spheroidal carboniferous particles (SCPs) were counted on the pollen slides to get an
independent chronological marker for the uppermost sediment(Renberg and Wik, 1984; Wik and Renberg, 1996).

Pollen and microcharcoal analysis
Subsamples were treated following Berglund and Ralska-Jasiewiczowa (1986). Lycopodium spores were added before treatment
to calculate pollen concentration (pollen grains/cm3) and pollen
accumulation rate (pollen grains/cm2·year). A minimum of 500
pollen grains per sample were identified and counted under
microscope with magnifications of 400 and 1000. We used pollen
and spore identification keys (Beug, 2004; Moore et al., 1991;
Punt et al., 1976–2003), the pollen and spore reference collections
at the Swedish Museum of Natural History and the Department of
Biology and Environmental Science, Linnaeus University (Kalmar, Sweden) for identification of pollen and spores. Two fractions of microscopic charcoal, longest axis ⩾10 – <50 µm and⩾50 µm were also counted on the pollen slides. Pollen diagrams
are plotted using the TILIA 2.0.41 software (Grimm, 1990). The
percentage diagram is divided into local pollen assemblage zones(LPAZ) and subzones (LPASZ) based on a stratigraphically constrained cluster analysis (CONISS; Grimm, 1987) of the pollen
percentages of all identified arboreal pollen (AP) and non-arboreal pollen (NAP) taxa.

Archeological maps
Mapping of the archeological data around Lillsjön is based on
known archeological remains archived in the database of archeological sites and monuments of the Swedish National Heritage
Board, Fornsök (Riksantikvarieämbetet, 2023, www.raa.se, lastconsulted in January 2023). It provides information on prehistoricand historical remains located on land and under water. In the areaof lake Lillsjön, the data derive from field surveys in the 1940s
and 1970s, and later archeological excavations and field evaluations. The archeological data were extracted within a 3.5-kmradius area around the center of Lillsjön, which is an estimate of

the lake’s relevant source of pollen (see below). The criteria for
selection of data were as follows: the objects had to be (1) a remnant of human activity in ancient times and permanently abandoned, (2) created and abandoned before 1850 CE, and (3)included in one of the categories listed in the Historic Environment (1988). A review of the existing dates and a new typologicalstudy of archeological objects were used for attribution of settlements and monuments to archeological periods.

Reconstruction of local andregional plant cover
We use the Landscape Reconstruction Algorithm (LRA; Sugita,
2007a, 2007b) to reconstruct changes in landscape openness inthe study region, locally around the small lakes Lillsjön, Hyttegöl
and Stärringen, and regionally within an area of 50 km radiusaround the large lakes Storsjön and Tjursbosjön (including two of
the three small lakes) (Figure 1; Table 1). The LRA comprises twomodels, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites; Sugita, 2007a) and LOVE (LOcal Vegetation Estimates; Sugita, 2007b). The theory and description of
the models and their parameters are provided in Supplemental
Appendix 1, available online. REVEALS was developed for pollen records from large lakes (⩾50 ha) (Hellman et al., 2008a;
Sugita, 2007a) to estimate plant cover within a large area estimated to ca. 104 km2 (or ca. 50-km-radius area) in southern Sweden (e. g. Hellman et al., 2008b). REVEALS can also be applied
using multiple pollen records from smaller lakes (<50 ha) (Sugita, 2007a; Trondman et al., 2016). LOVE is appropriate for pollen records from small sites only (lakes and bogs of a few hectares)
and estimates the local plant cover within the relevant source areaof pollen (RSAP; Sugita, 1994). The RSAP is the smallest spatial
scale of a LOVE reconstruction. LOVE needs REVEALS estimates of regional plant cover as input.
The LRA application in this study is described step by step in
Supplemental Appendix 1, available online (LRA strategy, chronologies, harmonization of pollen taxonomy, parameter setting,model runs and outputs) with additional information in Supplemental Table S1.1, available online. The values of relative pollen
productivities and fall speed of pollen, the two most importantparameters needed for the application of LRA, are provided inTable 2. For consistency, new age-depth models were performed
for Storsjön, Tjursbosjön, Hyttegöl, and Stärringen using the published 14C dates (see references in Table 1) and the same methods
as described for Lillsjön (see above).

Results
Lillsjön
Archeology. We summarize here the main results of the archeological analysis and mapping (Figure 2). More detailed information is provided in Supplemental Appendix 2, available online(Archeology). The dates of archeological periods in southern
Sweden follow the system of Hedeager and Kristiansen (1985),
slightly revised by Berglund (1991).
Thirteen sites within 3-km radius around Lillsjön can be
assigned to Stone Age (Figure 2a). A Late Mesolithic hunterfisher-gatherer settlement dated to ca. 5000 BCE is located 0.5-km
N of the lake’s western end (Gustafsson and Petersson, 2002).
Although there is no evidence of settlements dated to the Bronze
Age (1800–500 BCE) close to the lake, several of the isolated
grave cairns and stone settings can be dated to this period or the
Early Iron Age (Pre-Roman Iron Age, 500–0 BCE) (Figure 2b).
The over 60 cairns and ca. 200 stone settings, either isolated or ingrave fields, within 3-km radius of Lillsjön are all located on hill
tops. Permanent settlements and prehistoric farms were probably

60

The Holocene 34(1)Table 1. Pollen records used for the application of the Landscape Reconstruction Algorithm (LRA; Sugita, 2007a, 2007b).
Sites and references

Location and elevation(m a.s.l.)Storsjön
Ning et al. (2018)
Tjursbosjön
Karlsson et al. (2015)
Lillsjön
Stärringen
Almgren (2008)
Hyttegöl
Karlsson et al. (2015)

ha

km2

Numberof pollensamples*

210

2.1

77

4

Full period

1–19

99.6

57.71°N, 16.41°E, 51.3 m a.s.l. 120

1.2

27

3

690–2010 CE

1–7

98.5

57°56°N, 16°23°E, 16 m.a.s.l.
57.34°N, 16.47°E, 20.3 m a.s.l.

16 0.16 86
19.6 0.196 58

123

Full period
Full period

3–21
3–10

98.3
99.2

57.72°N, 16.46°E, 27.6 m a.s.l.

7

760 BCE–1992 CE 1–9

98.2

57.42°N, 16.14°E, 90 m a.s.l.

Size

0.07

32

Numberof C14
dates*

Time span of thepollen record*

Pollen counts used in LRA
Number of pollen % of total
counts per time terrestrial pollen
windowused in LRANames of large lakes are in bold. *Number within the study period (ca. 1000 BCE to present = full period). For the definition of time windows, see
Figure 5 and Supplemental Appendix 1, available online. Number of pollen counts = number of levels in the sediment core at which pollen were identified and counted. This number varies between time windows, the minimum and maximum number is provided. % of total terrestrial pollen used in
LRA = mean % of the 28 pollen types included in the LRA application (calculation sum = all pollen types from terrestrial plants).

Table 2. Relative pollen productivities (RPPs) with their standard deviations (SDs) and fall speed of pollen (FSP) used in this study.
Land-covertypes

Land-use categories

Coniferous
woodlandShade-tolerant trees and shrubs
Light-demanding trees and shrubs
Trees and shrubs on damp soil

Deciduous
woodlandShade-tolerant trees and shrubs

Light-demanding trees and shrubs
WetlandGrassland

Wet meadows
Dry pastures and heath vegetation
Fresh meadows and pastures

Ruderal communities

Cropland

Cultivated land

Pollen morphological types/
plant taxa

Picea
Pinus
Alnus
Salix
Acer
Carpinus
Fagus
Fraxinus
Quercus
Tilia
Ulmus
BetulaCorylus
Cyperaceae
Calluna
Juniperus
Poaceae (reference taxon)
Filipendula
Galium-type
Plantago lanceolata
Potentilla-type
Ranunculus acris-type
Rumex acetosa-type
Amaranthaceae/Chenopodiaceae
Artemisia
Compositae SF Cichorioidae
Cerealia-type
Secale cereale

FSP, m/s

RPP (SD)

Mazier et al. (2012); aAbraham
and Kozáková (2012)
0.035
0.031
0.021
0.022
0.056
0.042
0.057
0.022
0.035
0.032
0.032
0.024
0.025
0.035
0.038
0.016
0.035
0.006
0.019
0.029
0.018
0.014
0.018
0.019a0.025
0.051

1.76 (0.00)d
5.66 (0.00)d
4.20 (0.14)d1.27 (0.31)c
1.27 (0.45)c
2.53 (0.07)d
6.67 (0.17)d
0.67 (0.03)c
7.53 (0.08)d
0.80 (0.03)c
1.27 (0.05)c
8.87 (0.13)d1.40 (0.04)d
1.00 (0.16)c
1.10 (0.05)b
2.07 (0.04)d
1.00 (0)c2.48 (0.82)c
3.95 (0.59)c
0.90 (0.23)b
2.47 (0.38)c
3.85 (0.72)c
1.56 (0.09)b
4.28 (0.27)e
3.93 (0.14)e0.24 (0.06)c

0.060
0.060

0.75 (0.04)b
3.02 (0.05)d

The FSP values are from Mazier et al. (2012) and aAbraham and Kozáková (2012). The RPP values are from bDenmark (Nielsen, 2004), cSouthern
Sweden (Hellman et al., 2008b), and the syntheses for Europe of dMazier et al. (2012), and eGithumbi et al. (2022). The land-cover types are used in thesimplified diagrams of REVEALS regional and LOVE local plant cover (Figures 5 and 6, and the Figures in the Supplemental Appendix 2, available online),
and the land-use categories (following the indicator-species group from Gaillard (2013)) are used in Figure 4. The RPP value of the reference taxon(Poaceae) is set to 1, and the RPP values of all other taxa are related to Poaceae.

lying at lower elevations. Rock art and cup marks of the same age
at over 90 sites alongside heaps of fire-cracked stones, stone
fences, clearance cairns and prehistoric fields, are all testimonies
of a landscape strongly influenced by human activities.
Farms are mentioned in written sources first from the Middle
Age, for example, Lapserum (1383 CE), Fästad (1370 CE),
Dynestad (1382 CE), Gursten (1383 CE), Langeharg/Nygård

(1380 CE), Valstad (1412 CE), and Vida (1350 CE) (Axelsson,
2008; Figure 2c). Farms located nearby large grave fields, such as
Fästad, Langeharg/Nygård, Valstad, and Vida are assumed tohave existed already in the middle of the Iron Age (300–550 CE)(Brink, 1999; Palm, 2001). Clusters of grave fields located outside 2 km from the lake are dated to Late Iron Age (550–1050 CE)(Figure 2c). Farms and grave fields were closer to each other andVinogradova et al.

61

Figure 3. Age-depth model for the sediment cores from Lillsjön constructed using Bacon ver. 2.5.7 (Blaauw et al., 2022). 14C dates (blue) arecalibrated using the IntCal20 dataset (Reimer et al., 2020); the red stippled line corresponds to the model’s best fit based on the mean age foreach depth; the gray stippled lines delimit 95% confidence intervals.

located at lower elevations than during the Bronze Age, in areas
with nutrient-rich soils favorable to farming. Around the top of
the Gamlebyviken Bay, 1–3 km SE of Lillsjön, several large grave
fields, coins, and a Viking age maritime timber construction indicate that the area was of particular importance. A rune stone dating to the Late Iron Age standing at the farm Gursten, and otherfindings such as damaged graves suggest that the farm existed
before Middle Ages (Rydström, 1919). Mining for copper andiron existed in the region since Late Iron Age and probably even
earlier (Sandberg et al., 2011).
In the late 17th century and onward, several small farms andcrofts scattered in the landscape were established, some of themunder the administration of the larger farms Langeharg/Nygård in
the southeast and Olserum in the northwest. Figure 2d shows only
the farms that were abandoned before 1850 CE. Mining occurredfrom 1655 CE at Olserum. During the 17th century, the ore wasstill mined with fire, which required large quantities of wood.

Chronology, content in organic matter and sediment accumulation
rate. The age-depth model for the lake Lillsjön (Figure 3) isbased on 13 14C dates of which two have large errors, and two
are inversed (Supplemental Table S2.1, Appendix 2, available
online). Excluding these dates did not change the age-depth
model significantly (results not shown). The decrease (at 180 cm)
and increase (at 110 cm) of the estimated sediment accumulation
rates (SARs) are related to parallel decreases and increases of thepollen concentrations (PCs) and pollen accumulation rates(PARs) (Supplemental Figure S2.2, Appendix 2, available online),
which indicates that the low SAR values between 110 and 180 cm
are an artifact, at least partly. A slight increase in organic matter at
ca. 185 cm and decrease at ca. 120 cm (Supplemental Figure S2.1,
available online) may be related to changes in SARs, however notcertain. The peak (at 10 cm depth) and subsequent decline in spheroidal carboniferous particles (Figure 4) confirm the age-depth
model of the last century (Figure 3).

Pollen and microcharcoal analysis. The percentage pollen record(Figure 4) is dominated by APs (65–95%) with Pinus (25–55%)
and Betula (10–30%) being the most abundant tree taxa over theentire studied sequence, although Alnus, Corylus, Picea, andQuercus have values >10% in some periods. Among NAPs

(5–35%), Poaceae and Cyperaceae are dominant, followed by
Ranunculus acris-type, Filipendula, Rumex acetosa-type andArtemisia. A total of 96 pollen taxa were identified including 21
AP taxa, 52 terrestrial NAP taxa, five spores (fern and moss taxa),
eight aquatic taxa and 10 telmatophyte taxa (Figure 4 and rarepollen findings in Supplemental Table S2.3, Appendix 2, available online). Ten local pollen assemblage zones (LPAZs) wereidentified based on a CONISS analysis of the pollen percentagesof terrestrial plants.
The LPAZs are described in detail in Supplemental Appendix
2, available online. The pollen diagram provides a detailed historyof the local cultural landscape for the last 3000 years, from theend of Early Bronze Age to present. The LPAZs correspondroughly to fluctuations in the relationship AP/NAP, where boundaries between LPAZs correspond to an increase or a decrease inpollen % of NAP. The lowest % of NAP occurs in LPAZ 3 (ca.
2–3%), LPAZ4 and parts of LPAZ 2a and 7 (<10%), and thehighest % in LPAZ 1, 2b, 5, 6, and 8 (10–20%) and 9–10 (>20%
except for the most recent levels). Pollen indicators of agriculturalactivities (e.g. cereals, ruderals, and meadow/pastureland plants)
occur from the bottom of the pollen diagram and vary in percentages throughout the diagram, the most common being Poaceae(grasses), Cyperaceae (sedges family), Ranunculus acris-type(showy buttercup and other buttercup species), Filipendula(meadowsweet and dropwort), and Artemisia (common mugwort
and other mugwort species). Cereals (identified rye excluded) aremost common in LPAZ 6, 9, and 10, and Secale cereale (rye) in
LPAZ 9 and 10.
The largest change in tree pollen over LPAZ 1–4 is thedecrease of Corylus (hazel), Tilia (linden) and Fraxinus (ash) at
the end of LPAZ 1 from ca. 370 cm (ca. 850 BCE), followed byrelatively low values of these taxa through LPAZ 2 and the firstpart of LPAZ 3, whereas Populus (aspen) increases to reachmaximum percentages in LPAZ 4. Quercus (oak), Tilia, Fraxinus, and Ulmus (elm) increase at the end of LPAZ 3 and keephigh percentages in LPAZ 4. Major changes in woodland pollen
percentages occur from ca. 200 cm (ca. 200 CE) (LPAZ 4/5
boundary) with a decrease of Populus and all broadleaved trees(except Quercus) to very low percentages, while Alnus (alder)
exhibits a progressive decrease over LPAZ 5. This change corresponds to an increase in NAP (LPAZ 5), followed by the regular occurrence of Picea (spruce) from 173 cm (ca. 400 CE) with

Figure 4. Lillsjön: percentage pollen diagram with the most common pollen taxa, Pteridium aquilinum spore, two charcoal fractions (longest axis ⩾ 10 - <50 μm and ⩾50 µm), pollen from aquatics andtelmatophytes, and spheroidal carbonaceous particles (SCPs, left). The number of Pediastrum algae is the counted number for 100 Lycopodium spores (see Methods for details). The local pollen assemblage zones(LPAZ) and subzones (LPASZ) are based on a constrained cluster analysis (CONISS; Grimm, 1987). Colors represent groups of pollen taxa ascribed to different types of vegetation and land use (following Gaillard,2013). % (dark color) and ×10 exaggeration (shaded). Bluish green: trees and shrubs on damp soil; brownish green: shade-tolerant trees and shrubs; green: light-demanding trees and shrubs; turquoise blue: wetmeadows; dark pink: forest herbs and ferns; dark green: dry pastures and heath vegetation; orange: fresh meadows and pastures; dark red: ruderal communities; yellow: Cultivated land; dark blue: aquatics andtelmatophytes. Archeological periods: EBA Early Bronze Age 1800–1000 BCE (only the last part represented in the pollen diagram), LBA Late Bronze Age (1000–500 BCE), PrRIA Pre-Roman Iron Age (500 BCE–0),
RIA Roman Iron Age (0–400 CE), MP Migration Period 400–550 CE), VT Vendel time (550–800 CE), VA Viking Age (800–1050 CE), MA Middle Ages (1050–1500 CE), MT Modern time (1500 CE–present). Graybands around the boundaries between archaeological periods account for uncertainties in chronologies (see main text under Discussion and Appendix 3, available online).

62
The Holocene 34(1)Vinogradova et al.
up to ca. 5%. A second major change is the increase of Picea(>10%) from ca. 145 cm (end of LPAZ 6; ca. 800 CE) reachingclose to 20% at 135 cm (ca. 950 CE) accompanied by decreasesof broadleaved trees. Picea starts to decrease from LPAZ 8 (ca.
1500 CE) and most tree taxa decrease through LPAZs 7–8 toreach very low values in LPAZs 9–10, except Betula (birch) andPinus (pine).
Pollen concentrations (PCs: # pollen per cm3; Supplemental
Figure S2.2, Appendix 2, available online) and pollen accumulation rates (PARs: # pollen per cm2 and year; Supplemental Figure
S2.3, available online) may provide useful information for theinterpretation of pollen percentages. The major artifacts from percentage calculation are related to increases or decreases of very
common pollen types such as Pinus, Betula, and Alnus, for which
PCs and PARs may show that the change of percentage for one
pollen type is “real” while the parallel change (decrease in %) of
another taxon is an artifact, that is, there is no decrease of theabsolute abundance of the pollen type. This is the case for mostchanges in percentages of Pinus and Betula, for example, over
LPAZs 1–6. Similarly, an increase or decrease in AP % always
corresponds to a decrease or increase, respectively, of NAP %,although one of the change maybe a calculation artifact. Here,PARs do not indicate this type of artifact over LPAZs 1–5 (Supplemental Figure S2.3, available online). From LPAZ boundary
5/6, the interpretation of PARs and PCs is problematic due touncertainties in the calculation of sediment accumulation andother unknown factors. Nevertheless, the increase in PCs of AP
from the middle of LPAZ 7 (increases of Betula, Pinus, andPicea) is not related to a decrease of NAP PCs. For more detailson (1) PCs and PARs results and interpretation, see Supplemental
Appendix 2, available online and (2) uncertainties, see Supplemental Appendix 3, available online.

Pollen-based regional and local plant coverAge-depth models. The new age-depth models for the four additional sites used in the Landscape Reconstruction Algorithm(LRA) application are shown in Supplemental Figure S2.4, Appendix 2, available online). These models (i.e. chronologies) are basedon a smaller number of 14C dates than Lillsjön’s (Table 1; Figure 3)
and are less certain for some periods, that is, ca. 1000 BCE–0(Storsjön), ca. 500–700 CE and 1500–1800 CE (Tjursbosjön), ca.
1200–600 BCE and 0–1000 CE (Stärringen), and ca. 200–1000
BCE, 200–700 CE, and 1000–1600 CE (Hyttegöl). The age-depth
models also indicate the occurrence of sediment hiatuses (or very
low sediment accumulation rates) at Stärringen around 1000 CE,
and between ca. 1000 and 1500 CE at Hyttegöl, both confirmedby pollen data at ca. 55 cm (Almgren, 2008) and ca. 42 cm (Karlsson et al., 2015), respectively.
Regional REVEALS-based and local LOVE-based plant cover.
Because REVEALS and LOVE require values of relative pollen
productivities (RPPs), model-based estimates of plant cover canbe achieved for taxa for which RPPs are available, in this case 28
plant taxa (harmonized with 28 pollen morphological types/taxa,
see Methods for details). The 28 pollen taxa used in the REVEALS
and LOVE reconstructions represent 98.2% to 99.2% of the total
pollen from terrestrial plants (Table 1).
Regional REVEALS-based plant-cover estimates for the last3000 years from the Storsjön’s pollen record are presented in Figure 5a and Supplemental Figure S2.5, Appendix 2, available
online). For comparison, we show the REVEALS plant-coverestimates for the last 1300 years based on (a) the pollen record
from Tjursbosjön (Supplemental Figure S2.6, Appendix 2, available online) and (b) the pollen records from two of the small lakes
Lillsjön (L), Stärringen (S), and Hyttegöl (H) and the large lake

63
Tjursbosjön (T) (Figure 5b, Supplemental Figure S2.7, Appendix
2, available online).
Local LOVE-based plant-cover estimates around the threesmall lakes for the last 3000 years (Lillsjön, Stärringen) and2000 years (Hyttegöl) using the REVEALS regional plant coverfrom Storsjön are presented in Figures 5a and 6 and Supplemental
Appendix 2 Figures S2.8, S2.9, available online. For comparison,
we show the LOVE plant-cover estimates around the three smalllakes over the last 1300 years using the REVEALS plant coverbased on multiple sites (two of the three small lakes and the large
lake Tjursbosjön) (Figure 5b).
A specificity of LOVE reconstructions is that plant cover isestimated for the RSAP, that is, an area specific for each small
study site. RSAP is estimated by the LOVE model using regional
REVEALS-based plant-cover estimates and the pollen counts
from the small site. The LOVE model then subtracts the background pollen (coming from beyond the RSAP) from the small
lake’s pollen assemblages. It implies that pollen of some taxa can
get very low values or are absent from the pollen coming fromwithin the RSAP, which leads to absence of the plant within the
RSAP or very low cover estimates, often not different from zero
when the SE is considered. This is the case for, for example,
Betula (1150–550 BCE, 50 BCE–200 CE, 450–700 CE), Pinus(1150–550 BCE, 200–450 BCE, 700–1850 CE), and Juniperus(juniper) (1850 CE to present) at Lillsjön (Figure 6), althoughpollen percentages of these taxa are high (Figure 4). Therefore,
the LOVE reconstruction is not only dependent on the pollen
record from the small lake but is also influenced by the pollen
record used to reconstruct regional plant cover.
The size of RSAP for the three small sites was estimated in theLOVE model runs for each of the 11time windows. When the
REVEALS regional plant cover from Storsjön is used in theLOVE runs, RSAP estimates vary between 1820 and 3090 m
radius, and has a mean value of 2360 m (Figure 6). These values
agree with earlier RSAP estimates for small lakes in southern
Sweden in several empirical and simulation studies (e.g. Cuiet al., 2013; Fredh et al., 2019; Hellman et al., 2009a, 2009b) inwhich most of the estimates (radii) are falling in the interval
1000–3000 m.
The REVEALS and LOVE plant cover and their related standard error (SE) are plotted together with the pollen percentages(PPs) in Figure 6 and Supplemental Appendix 2, Figures S2.5 to
S2.9, available online. When SE ⩾ mean REVEALS or LOVEestimate, the plant cover is not different from zero, that is, it is notreliable. To avoid repetition, the major REVEALS and LOVE
results are described in the Discussion below, and details are provided in Supplemental Appendix 2, available online together witha description of the differences between PPs and estimated plant
cover.

Discussion
Uncertainties in chronologies and in the interpretation of pollen
data in terms of human-induced vegetation (via land use) are discussed in detail in Supplemental Appendix 3, available online.
Here, we summarize the major points to be considered in the discussion below. The uncertainties in the chronology of Lillsjön
imply that the attribution of inferred vegetation, land-use and landcover changes to archeological periods must be considered withcaution. A clear indication of a bias toward slightly too old ages as
inferred from Lillsjön’s age-depth model is the pollen curve andLOVE-based reconstruction for Picea (Figures 4 and 6). Its earliest LOVE-based local presence is dated to 200 CE, which is too
early if we rely on the studies by Bradshaw and Lindbladh (2005).
These authors dated the local establishment of Picea abies atthree sites ca. 50 km S of Gamlebyviken to ca. 1000 CE. This

64

The Holocene 34(1)Figure 5. REVEALS reconstructions of regional plant cover and LOVE reconstructions of local plant cover (a and b), and pollen percentages
for comparison (c). The 28 plant taxa used in the reconstructions (see Figure 6) are grouped into five land-cover types for an easiercomparison. Note that Juniperus is included in grassland, and coniferous woodland includes Pinus and Picea. The study period was divided into
11 Time Windows (TW) (see Supplemental Appendix 1, available online for rationale behind the definition of TWs and Supplemental Table
S1.1, available online for the TWs age boundaries). Archeological periods, see caption of Figure 4 for explanation of abbreviations and ages.
(a) REVEALS reconstruction of regional plant cover using the pollen record from Storsjön, and LOVE reconstruction of local plant cover using
the pollen records from the three small lakes Lillsjön (L), Stärringen (St), and Hyttegöl (H) using the regional vegetation cover from Storsjön.
(b) LOVE reconstructions of the local plant cover for the same three small lakes L, St, and H, with the regional plant cover obtained fromREVEALS reconstructions using the pollen records from Tjursbosjön (large lake, T) and two of the pollen records from small lakes, that is,
the “leave-one-out approach,” St+H+T, L+H+T, and L+St+T for Lillsjön, Stärringen, and Hyttegöl, respectively. (c) Pollen percentages forStorsjön, the three 3-lakes alternatives StHT, LHT, and LStT, the three small lakes L, St, and H, separately, and the large lake T. For details on
REVEALS and LOVE reconstructions, see Supplemental Appendix 1, available online.

would support our assumption of too old ages by a few centuries.
For comparison, the front of Picea abies migrating from Northeast and East reached Stockholm area ca. 1000 BCE and our study
region ca. 0 CE according to Seppä et al. (2009), adapted from

Giesecke and Bennett, 2004). More recent maps of the tree migration in Europe by Giesecke et al. (2017) based on all pollen
records archived in the European Pollen Database rather than afew selected pollen records (Giesecke and Bennett, 2004; SeppäFigure 6. Lillsjön: LOVE estimates of local plant cover (in % cover, colored) and pollen % (gray). The REVEALS estimates of regional plant cover from Storsjön were used in the LOVE model to calculate therelevant source area of pollen (RSAP), that is, the radius of the area representing the spatial scale of the reconstruction (see Figure 1). Green: deciduous trees; dark green: conifers (except Juniperus); turquoise:
Cyperaceae (wet meadows); orange: grassland; yellow: cropland. The archeological periods are shown for comparison (see caption of Figure 4 for explanation of abbreviations and ages). For details see Methods
section, and Supplemental Appendix 1, available online.

Vinogradova et al.
65

66
et al., 2009) indicate the regional presence of Picea abies at thelocation of Stockholm at 4000 BCE (approximation of theregional presence, class 1) or 2500 BCE (using a more conservative threshold for presence, class 2). At 2000 BCE an increased
abundance (class 3) is suggested. In our study region, the firstregional presence is dated in Giesecke et al. (2017) to 2500 BCE(class 1) or 0 CE (class 2), and an increased abundance (class 3)
to 1000 CE. If establishment is defined as an increased abundance
rather than just presence of the species, the results from Giesecke
et al. (2017) agrees with those from Bradshaw and Lindbladh(2005) for our study region. Although recent studies of ancient
DNA suggest that small populations of Picea were already present in southern Sweden since Late Glacial, it is first during a second colonization, starting 5000 BCE in northern Sweden and4000 BCE around Stockholm (Giesecke et al., 2017), that it built
continuous woodland stands (Nota et al., 2022).
The dates of each archeological period boundaries according
to Berglund (1991) are given the first time the period is mentioned
below. These dates provide an approximate age for the start andend of the periods based on many 14C dates from southern Scandinavia. However, the boundaries are not sharp but rather transitions that may cover several centuries. Therefore, they are
represented by gray bands in Figures 4 to 6, and Figures S2.5–
S2.9 (Supplemental Appendix 2, available online). Furthermore,
the uncertainties in chronologies of all sites imply that the time
windows used in the REVEALS and LOVE reconstructions cannot be expected to be exactly synchronous between sites/reconstructions, that is, one should consider errors of ±200 years on theages of the boundaries between time windows.
Pollen grains can seldom be identified to the plant species, but
can be ascribed to the family, group of genera, or genus. Therefore, it is not possible to quantify with precision the cover ofhuman-induced vegetation types as many of their characteristic
pollen types/plant taxa may also grow in natural vegetation.
Therefore, the REVEALS- or LOVE-estimated landscape openness (herbs cover) approximates deforestation by humans, however the cover of wetland (here represented by Cyperaceae only)
and grassland together may overestimate the cover of grazed land
and hay meadows in various degree depending on the site andperiod. In contrast, the cover of cropland is always underestimated as it represents only cereals. Other crops have either poor
pollen productivity (and are rare in pollen records) or cannot be
distinguished from wild species and are therefore included ingrassland. Finally, one should remember that LOVE and
REVEALS reconstructions do not include bare ground. Because
the cover of bare ground is naturally high in the study region due
to exposed bedrock and thin soils, absolute changes in LOVE and
REVEALS cover of wooded and herb vegetation would besmaller in actual percentage cover if the cover of bare ground wasincluded. For instance, if bare ground represents 50% of the
RSAP of a small lake, and the LOVE-based cover of total trees
and total herbs is 20% and 80%, respectively, it implies that theiractual cover is 10% and 40%, respectively. The values of cover
we are providing below are always higher than the actual cover.
Given that we have no measure of the cover of bare groundthrough time, we cannot adjust the REVEALS and LOVE coverestimation accordingly.

The local cultural landscapearound Lillsjön during the last3000 years
Here we discuss the cultural landscape history around lake Lillsjön using all information from the pollen record, that is, pollen
percentages (PPs) (Figure 4; Supplemental Table S2.3, Appendix
2, available online), pollen concentrations (PCs) (Supplemental
Figure S2.2, available online), PARs (Supplemental Figure S2.3,

The Holocene 34(1)available online), LOVE estimates of local plant cover within thelake’s relevant source area of pollen (RSAP) (Figures 5 and 6),
and the information from the analysis and mapping of the archeological findings around the lake (Figure 2).
Anthropogenic indicators of agriculture (pollen of herbs andlow shrubs belonging to cereals, weeds, ruderals, and plants characteristic of hay meadows and/or pastureland; Gaillard, 2013)
occur from the bottom of the pollen diagram (Figure 4). Moreover, each local pollen assemblage zone (LPAZ) is clearly definedby changes in composition and total percentage of both AP and
NAP, as well as changes in LOVE-based local plant cover within
the lake’s RSAP (ca. 2000–3000 m radius, Figure 6). These characteristics indicate a dynamic landscape history with continuous
agricultural activities around the lake that are changing in character and intensity both in time and space.

LPAZs 1 and 2 (ca. 1200–200 BCE: Bronze Ageand Early Iron Age)The bottom of the pollen diagram is dated to the end of the Early
Bronze Age (1800–1000 BCE). However, possible reservoir andhard-water effects may imply that LPAZ 1 represents only theLate Bronze Age (1000–500 BCE). Similarly, LPAZ 2 might correspond to the entire Pre-Roman Iron Age (500 BCE–0).
The archeological data indicate extensive human activities in
the area during the Bronze Age and the transition to the PreRoman Iron Age (Figure 2b and c). The LOVE-based local coverof trees in LPAZ1 is dominated by Corylus (30%), followed by
Tilia (13%). Carpinus (hornbeam) may have grown locally,
although in very small quantity, whereas Pinus, Betula, and Salix(willow) were probably not growing within the RSAP of Lillsjön.
Corylus and Tilia decrease in cover in LPAZ 2 to 17% and 7%,
respectively, while the cover of Alnus increases from a low percentage cover to 20%. Identical relative changes are shown in thePPs, PCs, and PARs. Corylus may have been coppiced for woodand Tilia pollarded for fodder during the Bronze Age. Pinus, Betula and Salix are present with a cover of 10%, 5%, and 1%,
respectively. Carpinus exhibits a slight increase of cover.
This period is characterized by a relatively high LOVE-based
local cover of open land (ca. 25–32% cropland and grassland
together, ca. 30–35% with Cyperaceae included). Pollen of
Cerealia type (belonging to Hordeum (barley) and Triticum(wheat) pollen-morphological types) occur throughout LPAZs 1
and 2, which suggests arable land within the RSAP. The presenceof Secale cereale and Centaurea cyanus (cornflower) (Supplemental Table S2.3, Appendix 2, available online) indicates that rye
may have been cultivated (e.g. Behre, 1981; Gaillard and Göransson, 1991; Körber-Grohne, 1987). Herbs indicating grazing land
and meadows are well represented as pollen and in the plant cover(Ranunculus acris type, Filipendula, Rumex acetosa type (sorrels
and docks), Plantago lanceolata (ribwort plantain), Poaceae; withregular occurrences of Anthriscus sylvestris (cow parsley), Aster
type (several genera of the aster family, e.g. asters, beggarticks,
cudweeds, etc.) and Potentilla-type (cinquefoils and strawberries)(Supplemental Table S2.3, available online) as well as herbs common in ruderal land (Artemisia (mugwort, wormwood, sagebrush,etc.) in particular, but also Plantago major/media (broadleaf plantain/hoary plantain) and Urtica (nettles) (Supplemental Table
S2.3, available online). The LOVE-based local cover indicates that
Poaceae are dominant (20%) followed by Compositae Cichorioideae (chicory subfamily in the aster family, e.g. lettuce, dandelions, chicory, etc.) (5%) and Juniperus (3%).
Microcharcoals have relatively high values in LPAZ1,
decrease over the transition to LPZA 2, and reach minimum values in subzone 2a corresponding to low PPs and LOVE cover ofruderal herbs, grazing land (Juniperus), and meadows (Plantago
lanceolata) (Figures 4–6). In combination with the changes inVinogradova et al.
tree composition, these changes may indicate abandonment ofsome open land areas within the lake’s RSAP, but it cannot be
confirmed by the archeological data. The findings ascribed to
Early Iron Age are numerous, but they are mostly associated toBronze Age findings.
A decrease in open land at the beginning of the Pre-RomanIron Age has been discussed in the southernmost province of
Sweden, Scania (Berglund, 1991). Rather than representing areal decline of human pressure on the landscape, it was suggested that such a decrease could result from a concentration ofagricultural land to the immediate vicinity of settlements/farms(e.g. Tesch, 1991; Tesch and Olausson, 1991), which was supported by some archeological data (e.g. Callmer, 1991a, 1991b;
Olausson, 1991a, 1991b). A similar development at the transition between Bronze Age and Pre-Roman Iron Age is suggested
by pollen data in the provinces of Blekinge (southeastern Sweden, e.g. Åkesson et al., 2015; Berglund et al., 2007, 2021) andSmåland, (e.g. Berglund et al., 2002; Cui et al., 2013; Digerfeldt, 1972; Lagerås, 2000, 2002).
The increase in PPs and LOVE-based local cover of Alnus anddecrease in PPs of aquatic plants at the LPAZ 1/2 boundary, as
well as the peak in the algae Pediastrum in subzone 2b (Figure 4),
may be due to a drop in lake water-level. Interpretation in termsof lake-level changes based on data from a single core is uncertain(e.g. Digerfeldt, 1988). Nevertheless, low lake-levels starting
around the Bronze Age/Pre-Roman Iron Age boundary wereinferred from detailed studies in Scania and Småland (Digerfeldt,
1988; Gaillard and Digerfeldt, 1991). These events may be related
to the Roman Warm Period (see further discussion, below).

LPAZs 3 and 4 (ca. 200 BCE–220 CE: Early Iron
Age)
This period is dated to the last part of the Pre-Roman Iron Age andthe first part of the Roman Iron Age (0–400 CE). We cannot ruleout the possibility of a slightly too old age (see above).
The LPAZs 2/3 boundary corresponds to a significant decreasein PPs, PCs, PARs and LOVE-based local cover of anthropogenic
indicators that remain low until the end of LPAZ 4, with a minimum NAP cover of 5% during the Roman Iron Age. The tree PPs
and PARs show an increase in Fraxinus, Tilia, Quercus, Ulmus(elm), and Corylus, and a decrease in Pinus over the transition
between LPAZ 3 and 4. At the same time, Populus tremula (aspen)
exhibits a slight, but clear increase in PPs, and keep similar values
until the end of LPAZ 4. The increase in broad-leaved trees is also
clear in the LOVE-based local tree composition (time window 50
BCE–200 CE (Figure 5). Corylus (27%) is still dominant in thelocal tree cover, followed by Tilia and Fraxinus (12%), Quercus(6%), and Ulmus (5%).
Herbs indicative of human activities have very low PPs, PAR,and LOVE cover or are absent from the record (LPAZs 3 and 4).
The absence of pollen from Cerealia type and Secale cereale indicates that cereal cultivation probably ceased locally. Meadowsand grazing land were probably abandoned around Lillsjön,
which favored the local growth of Fraxinus, Quercus, Ulmus, andPopulus.
A less intensive land use during the Roman Iron Age andMigration Period (400–550 CE) has been discussed for southern
Sweden and tentatively ascribed to restructuring due to climatechange and/or socio-economical changes associated with anunsustainable agrarian system during Bronze Age and Pre-Roman
Age (e.g. Tesch, 1991; Tesch and Olausson, 1991). It was suggested that the Pre-Roman Iron Age and Roman Iron Age period
represented the transition between an extensive use of the landscape to a more concentrated use close to settlements. Trees suchas ash and elm may have been pollarded for fodder and wood, andhazel coppiced. Such an interpretation is also plausible for our

67
study area. The archeological data (Figure 2c and d) show that the
Medieval villages assumed to be related to Iron Age settlements,that is, Fästad, Vida, Langeharg and Valstad, are all located >1–
2 km from Lillsjön. Our results may indicate that arable land andmeadows moved progressively from the lake’s surroundings that
may have been abandoned for a century.
The studies of lake-level changes available in Scania andSmåland indicate low lake levels during Early Iron Age from ca.
500 BCE to ca. 500 CE (Digerfeldt, 1988; Gaillard and Digerfeldt, 1991), which may be correlated to the Roman Warm Period(generally dated to 250 BCE–400 CE, e.g. Campbell et al., 1998).
Recent reanalysis of global climate proxy data has shown that
there is no evidence of globally coherent warm and cold periods
over the last 2000 years, except for the last 150 years of global
warming (Neukom et al., 2019). Nevertheless, although notexactly of the same length in all studies, a warm period corresponding to all, or part of the Roman period was documented inEurope based on various types of climate proxy data. The evidence of a warmer climate supports the interpretation of a reorganization of land use from extensive during Bronze Age toconcentrated around settlements in the Iron Age, rather than adecrease in land use with a decrease in population due to climatechange. However, the Migration Period (ca. 400–550 CE) was aturbulent time in all Europe, which influenced Scandinavia. In
southern Sweden, it led to regional conflicts between local kingsand rich landowners, not least in our study region (Alfsdotter
et al., 2018; Lindström, 2022). Such conflicts may have caused
local abandonment of farms or settlements.

LPAZs 5 and 6 (ca. 220–900 CE: Late Early Iron
Age–Late Iron Age)
LPAZs 5 and 6 are dated to the period from the later part of the
Roman Iron Age to the first part of the Viking Age (800–1050
CE). The LPAZs 4/5 boundary may correspond to the beginningof Late Iron Age (Vendel Period, 550–800 CE). There are only
three locations with archeological findings dated specifically to
the Late Iron Age within 3 km of Lillsjön. Besides, findings fromnine locations are dated to the Iron Age without further specification. Of these 12 locations, only four are within 2 km of Lillsjön.
However, most concentrations of grave fields dated to the Late
Iron Age (550–1050 CE) are situated beyond 3 km from Lillsjön
and often associated to a farm. Moreover, they are located atlower elevations than during the Bronze Age and Early Iron Age.
SE from the lake, close to the northern part of the bay Gamlebyviken, several large grave fields and a Viking Age maritime
timber construction are testimonies of an area of particular importance during the Late Iron Age. According to the latest shore displacement curve for the Gamleby area (Katrantsiotis et al., 2023),
the shoreline dropped from 11 m a.s.l. at the onset of the Bronze
Age down to 3 m a.s.l. at the beginning of the Late Iron Age,
which might be one of the reasons behind the move of farms andgrave fields to new, lower elevations.
A significant increase of NAP PPs and a related decrease in AP
PPs at the LPAZs 4/5 boundary are confirmed by PCs and PARs.
PPs and PCs keep similar values until the end of LPAZ 6. The
LOVE-based NAP cover is ca. 43% (50% with Cyperaceae) in
LPAZ 5 and the beginning of LPAZ 6 (ca. 250–450 CE), which issignificantly larger than during the Late Bronze Age. It thendecreases to ca. 30% (36% with Cyperaceae). The LOVE cover of
cereals reaches a maximum of ca. 5% in the time window 500–
700 CE. LPAZ 5 is characterized by a peak in microcharcoal. Cultivated fields and hay meadows were close to the farms, and therest of the landscape was used for grazing. With time, more land
was needed, and Lillsjön’s RSAP was used again, however primarily for grazing. The latter is also confirmed by the LOVEbased increase in cover of Juniperus (up to 5%) and Poaceae (up68
to 30%). The continued presence of Juniperus and the increase in
Calluna (heather) in LPZ 6 suggest that Lillsjön was used for
grazing during the entire period. The increase in Cerealia type to
5% cover and the occurrence of Secale cereale and Centaurea
cyanus pollen indicates the occurrence of some arable land within
Lillsjön’s RSAP.
The trees favored earlier by ca. a century of land-use abandonment around Lillsjön, Fraxinus, Quercus, Ulmus, Tilia, and Populus decreased in cover. In contrast, Corylus became moreabundant, which may also be an indication of coppicing. Whencoppiced over long time, hazel stands will become less dense,
which will favor flowering and lead to an increase in pollen production. Carpinus and Fagus seem to be favored locally by thechange in land-use. Picea is present locally from 200 CE (probably too old age, 500 CE is more plausible, see discussion on chronology at the beginning of the section) and increased from 5% to
20% cover in the last part of LPAZ 6. Pinus is absent again fromthe RSAP from 200 CE to 450 CE and represented with very low
cover from 450 CE to 950 CE.
PPs, PCs, and LOVE-based cover of Alnus decrease over
LPAZ 5 and remain low throughout LPAZ 6, while values of telmatophytes and aquatics increase, which may be due to a rise inlake water-level and coincide with the period of rising and highlake levels ca. 500–700 CE in southern Sweden (Digerfeldt, 1988;
Gaillard and Digerfeldt, 1991).

LPAZs 7 (ca. 900–1500 CE: Late Iron Age-Middle
Ages)
LPAZ 7 is dated to the later part of the Viking Age and entire
Middle Age (1050–1500 CE) but may correspond to Middle Ages
only. Although many farms of the area are assumed to have been
established already in the Iron Age, none of them are named in
written sources before the 14th and 15th centuries (1300–1400
CE). Therefore, the density and size of farms in Lillsjön’s RSAPin early Middle Ages is not known.
At the LPAZs 6/7 boundary, a slight decrease in PPs, PCs, andPARs of NAP corresponds to a very clear decrease in LOVEbased NAP cover to ca. 15% and low microcharcoal percentages.
All indicators of human activities are decreasing at the LPAZs 6/7
boundary, except Ranunculus acris-type. The only tree taxon that
increases significantly is Picea, from ca. 20% to 55% cover.
Pinus is absent from the RSAP over LPAZ 7. There is little change
in the cover of broadleaved trees, except Corylus decreasing significantly from ca. 20% to 5% in subzone 7a, which may indicate
local abandonment of coppicing for a few centuries, rather than adecrease in cover. All these changes suggest a decrease in land use
within the Lillsjön’s RSAP during early Middle Ages. The latter
may have triggered the large increase in Picea. A similar development was described at two of the sites located south of Lillsjön
studied by Bradshaw and Lindbladh (2005).
The 7a/7b boundary (1250 CE) is characterized by a slightincrease in NAP PPs, PCs and PARs, an increase in LOVEbased NAP cover to 18% (22% with Cyperaceae) and in microcharcoal percentages. Subzone 7b is distinguished from 7a byslightly larger LOVE-based cover of some land-use indicators(Poaceae, Rumex acetosa-type and Amaranthaceae/Chenopodiaceae (amaranth family with e.g. goosefoots, saltbush, orach).
Pollen of Cerealia-type is again more common, suggesting thatcultivation of cereals occurs within Lillsjön’s RSAP. Pollen of
Cannabis-type (hemp and hop (Humulus lupulus)) occur regularly for the first time, which may be related to hemp retting in
Lillsjön, a procedure that existed in southern Sweden since theVendel time to obtain fibers for making fabrics and ropes (e.g.
Gaillard et al., 1991). The parallel increase in the algae
Pediastrum supports this interpretation, as hemp retting led to
an increase in nutrient content of lake water. Corylus shows

The Holocene 34(1)slightly higher cover, while Quercus, Tilia and Ulmus have very
low pollen values and cover. Fagus cover is still small, and its
local occurrence is uncertain. Picea starts to decrease slightly.
These are all indications of a renewal of land-use activities in
Lillsjön’s RSAP from ca. 1250 to 1500 CE.
There is no indication that the Medieval Climate Anomaly(MCA; generally dated to ca. 950–1250 CE, for example, Mannet al., 2009) would have influenced land use in the study area. It is
more likely that land-use decrease in Lillsjön’s RSAP is related toa reorganization of the agrarian system, from a one-course rotation
system to a strict three-course rotation system (fallow-rye-barley)
fully established from the 13th century. Such a development was
proposed for southernmost Sweden by multidisciplinary studies(e.g. Engelmark and Hjelmqvist, 1991; Gaillard and Göransson,1991). It was accompanied by the crystallization of the infield/
outland agrarian system with arable land and hay meadows in theinfield near the farms and grazing land outside the enclosed
infields, in vast outfields.
The temporal resolution of the pollen analysis and LOVEbased reconstruction does not allow to draw clear conclusions on
the possible effect of the medieval plague outbreak in Sweden ca.
1350–1450 CE (Lagerås, 2016; Myrdal and Morell, 2011).

LPAZs 8, 9, and 10 (ca. 1500 CE to present:
Modern Time)
LPAZs 8–10 are dated to Modern Time. All farms dating to early
Middle Age or earlier did still exist until 1850 CE.
The LOVE-based NAP cover increases from ca. 18% (22%with Cyperaceae) (LPAZ 7) to ca. 36% (47% with Cyperaceae)
ca. 1500–1650 CE (LPAZ 8) and to a maximum of ca. 63% (80%with Cyperaceae) ca. 1650–1890 CE (LPZ 9). It implies a doubling of the landscape openness in Lillsjön’s RSAP at the transition between Middle Ages and Modern time, and almost adoubling from ca. 1650 to 1890 CE.
Among pollen indicators of land use, Juniperus and Rumex
acetosa-type increase in cover from LPAZ 7 to LPAZ 8. Compositae Cichoriodeae and Cerealia-type, absent locally in LPAZ 7,
are present in LPAZ 8 with a cover of 8% each, and Centaurea
cyanus pollen occur again. Cannabis-type has its highest pollen
values corresponding to a peak of the algae Pediastrum, suggesting that hemp retting in the lake was common during this period.
There is a significant decrease in all tree taxa except Betula,
Quercus and Alnus (PPs, PARs and LOVE-based cover). Corylus
decreases from 12% to 5% cover and Picea from 35% to 20%. All
these changes suggest that the area was cleared again for both
grazing and cereal cultivation. The occurrence of fire is also indicated by peaks of microcharcoal values.
LPAZ 9 (ca. 1650–1890) is characterized by increases andhigh values of PPs and LOVE-based cover of Juniperus, Poaceae,
Cyperaceae, Cerealia-type and Secale cereale, the three latter taxa
reaching their largest cover of the entire studied period. Centaurea cyanus has its highest PPs in LPAZ 9, and Anthriscus sylvestris, Anthemis-type, and Trifolium repens (white clover) theirhighest PPs in LPAZ 9 and 10 (ca. 1890 to present). Alnus andPicea each decrease to ca. 5% cover in LPAZ 9, while Cyperaceae
increases to 15% cover. Pinus is again present in the RSAP withlow cover from 1700 CE. Among the remaining deciduous trees,
Alnus, Betula, and Quercus have the largest cover (ca. 9%
together). These changes indicate a major increase in area of managed land for grazing, hay making and cultivation of crops, with aclear maximum of cleared land representing 80% of the Lillsjön’s
RSAP area in the time window 1650–1890. The significant
decrease in tree cover may also partly be due to the mining activities that occurred at Olserum since 1655 CE (Figure 2). The ore
was broken by fire and required a large quantity of wood until it
was replaced by powder in the 18th century, and later by dynamite

Vinogradova et al.
(Hed Jakobsson, 2012). The increase in cereals to ca. 20% cover,
and abundance of Secale cereale show that the size of cultivatedfields within Lillsjön’s RSAP increased significantly, and thethree-course rotation system was still predominant. Alder groves
were progressively cleared for mowing and grazing. Cannabis
type decreases significantly together with the algae Pediastrum(Figure 4), which indicates the abandonment of hemp retting in
the lake from ca. 1650 CE. There is no indication of an impact of
the Little Ice Age (1450–1850 CE; IPCC, 2021) on land use.
The 20th century (LPAZ 10) is characterized by a local afforestation (increase in total tree cover from ca. 20% to ca. 32 %) due
primarily to the increase in cover of Pinus and Picea. Pinus
reaches ca. 10% cover (from 2% in LPAZ 9) and Picea increases
to ca. 8% (from 5% in LPAZ 9). Secale cereale decreases significantly together with herbs indicative of traditional hay meadowssuch as Plantago lanceolata, Potentilla-type, and Ranunculus
acris-type. The traditional three-course rotation system is gradually abandoned and replaced by modern agriculture with theintroduction of synthetic fertilizers. The large values of Poaceae
may be due partly to cultivation of leys for fodder. Brassicaceae
and Caryophyllaceae pollen have their highest values of the profile in LPAZ 10 and may be related to new crops and weed species, such as Brassica napus (rape) and Stellaria media(chickweed). Ulmus and Carpinus may have been planted aroundfarms, as well as Juglans regia (walnut) (present in LPZs 9 and
10, Supplemental Table S2.3, Appendix 2, available online), a
practice that was common in southern Sweden at the end of the
19th century and beginning of 20th century (e.g. Gaillard andGöransson, 1991; Gaillard et al., 1991).

Is the land-use and landcover history around Lillsjön
representative of the Gamleby
region?
The LOVE-based reconstructions of local plant cover around thesmall lakes Stärringen and Hyttegöl (with a RSAP of ca. 2000–
3000 m radius as Lillsjön) provide a picture of the between-site
variability in land-use and land-cover change. The REVEALSbased reconstructions of regional plant cover inform on the overall land-cover change, that is, they represent a “mean” of all local
changes within an area of 104 km2.

Local land-use and land-cover history
Hyttegöl is located ca. 23 km south of Lillsjön in a similar geological context although till is more abundant and clay-silt lessabundant than around Lillsjön (Figure 1). The LOVE-based
reconstruction of local plant cover around Hyttegöl covers thelast 1800 years (Figure 5 and Supplemental Figure S2.8, Appendix 2, available online). The LOVE-based reconstructions ofLillsjön and Hyttegöl are most alike when Storsjön pollen data isused for the regional plant cover rather than the combined Stärringen-Lillsjön-Tjursbosjön pollen data (Figure 5). The two sites
show the same decrease in grassland from 200 to 700 CE, withalmost as high cover of grassland and cropland 200–450 CE(Migration Period, possibly Vendel Period). There is a very significant increase in grassland cover (Cyperaceae included) fromlate Middle Ages around Hyttegöl and from the start of Modern
Time around Lillsjön, with a maximum cover reached for bothsites 1700–1850 CE, and a decrease thereafter. There is a larger
cover of conifers at Hyttegöl than Lillsjön 200–950 CE, which isdue to the presence of Pinus within the RSAP of Hyttegöl
throughout the studied period, with ca. 30% cover 200–1200 CE,
while Pinus is probably not growing within Lillsjön’s RSAP,
except 500 BCE–200 CE and during the last century (Figure 6

69
and Supplemental Figure S2.8, Appendix 2, available online).
The large cover of Pinus around Hyttegöl might be due to theabundance of exposed bedrock in the area. The major differencein land use between the two sites is the occurrence of intensified
mining activity and the establishment of locally operated blast
furnace upstream Hyttegöl as early as the end of the 12th century(Karlsson et al., 2015), which may explain the lower cover ofconifers and the larger landscape openness all through Middle
Ages when compared to Lillsjön.
Stärringen is located ca. 67 km south of Lillsjön and ca. 43 km
South of Hyttegöl in a geological context very similar to that ofHyttegöl (Figure 1). However, its pollen-based land-use andland-cover history are very different from both Hyttegöl and Lillsjön (Figure 5, Supplemental Figure S2.9, Appendix 2, available
online). From 1150 BCE to 950 CE, there is no major change inland cover within Stärringen’s RSAP. Grasslands decrease gradually from ca. 15% cover 1150–500 BCE (Bronze Age) to aminimum of 10% cover 200–450 CE (Migration Period and Vendel Period). Stärringen was probably located in the outland of
settlements/farms located at some distance outside the lake’s
RSAP from Bronze Age to Late Iron Age. It is first in the early
Middle Ages that a major change occurred. Grassland cover
increased locally from ca. 13% 700 to 950 CE (Vendel-Viking
Age) to ca. 52% 950–1200 CE (Viking Age-Middle Ages), andcereals (Cerealia type and Secale cereale) reached ca. 2.5%
cover. This large transformation is related to the establishment of
the farm “Stenzöö” (today’s Stensjö village) documented in written sources from 1351 CE (Almgren, 2008). From that time,
Stärringen is located within the infield of the medieval farm, withcultivated fields and hay meadows, which is suggested by thehigh cover of Plantago lanceolata, Rumex acetosa-type andcereals, with Secale cereale as an indicator of the three-course
rotation system. The large cover of Juniperus and Poaceae ischaracteristic of both the infield and outland. Juniper was a common element of the agrarian system in southern Sweden from
Early Middle Ages to ca. 1850 (e.g. Berglund et al., 2002, 2021;
Gaillard et al., 1991). From 450–700 CE to 700–950 CE, Picea
increased from ca. 2.5% to ca. 20% cover, which indicates a relatively rapid increase occurring within the period 700–950 CE(transition Migration Period-Viking Age). Picea started todecrease from 950 CE and reached a minimum cover 1200–1450
CE in connection with the development of the farm and a maximum cover of grassland and cereals. Land-use did not change
significantly until ca. 1700 CE, except a first decrease in grassland and cereal cover from ca. 1450 CE while Picea and Pinus
expanded again within the RSAP area. From the 18th century, thetraditional three-course rotation system was gradually abandoned, and Picea expanded in the outland at the expense of Juniperus. Juniper does not flower in the shadow of other trees and,
although it can survive for some decades, it finally dies. Thechange in agro-system increased the crop yield during the 19th
century. However, the increase in number of fields often led tothe use of land with low productivity (e.g. Olsson, 1991). Crop
yields started to decrease, and farmers gradually moved out of
Stensjö village from ca. 1900 CE, and the last farm was abandoned in 1951 (Almgren, 2008).

Regional land-use and land-cover history
The lake Tjursbosjön is located close to Hyttegöl and its pollen
record represents the regional vegetation around Hyttegöl ca. 600
CE to present (Karlsson et al., 2015) in an area of ca. 50 km
radius. The geological contexts of Tjursbosjön and Storsjön are
similar, although till and glaciofluvial deposits are more abundant, and bedrock less abundant, within 50 km radius of Storsjön
than Tjursbosjön (Figure 1), which may explain the main difference between the two sites in terms of plant cover, that is, larger

70
cover of Picea and smaller cover of Pinus in the Storsjön than in
the Tjursbosjön region. The alternative REVEALS-based reconstructions of regional vegetation using the pollen records of two
small sites and Tjursbosjön for the last 1300 years are very similar
to that from Storsjön when Lillsjön and Hyttegöl are the two
small sites used (Figure 5b). Therefore, the larger grassland cover
700–950 CE compared to 950–1200 CE appears to be characteristic of the region, while the local development at Stärringen isrepresentative of the land cover around Late Iron Age-Middle
Age farms/villages, but not of the overall regional vegetation
cover. The very small cover of grassland at Lillsjön during a partof the Early Iron Age (ca. 50 BCE–200 CE) has no equivalent at
any of the studied sites and is obviously a time of local abandonment of the area for grazing and cultivation that did not correspond to a regional feature.
The pollen record from Storsjön provides the best possible
reconstruction of regional plant cover for the period 1150 BCE to
700 CE, given that the pollen record from Tjursbosjön doesn’tcover this period (Figure 5a). For the last 1300 years, the reconstructed cover of conifers might be slightly too large, as well as
the cover of Picea in relation to Pinus to represent the easternmost part of the study region, and the reconstruction from Tjursbosjön might be more appropriate for the LOVE reconstruction of
local plant cover at Lillsjön, Hyttegöl and Stärringen during that
period (Figure 5b). For instance, the decrease in local cover ofgrassland in favor of tree cover during the last century at Lillsjön,
Hyttegöl, and in the REVEALS reconstruction using two small
sites and Tjursbosjön (Figure 5b) is not visible in the regional
vegetation cover from Storsjön.

Conclusions
This study aimed to test the assumption that periods of extensive
and intensive exploitation of the land by humans before the 19th
century, both locally and regionally, led to deforestation andopening of the landscape of a comparable magnitude to thatshown from the 19th century at Storsjön (Ning et al., 2018) andtherefore may have affected the Baltic Sea earlier.
We are showing here that the regional landscape openness
inferred from the pollen record of Storsjön was almost as large asin the 19th century already 700–950 CE (Viking Age). The
increase in landscape openness from 50 BCE–200 CE to 700–950
CE (Roman Iron Age to Viking Age) from ca. 22% to 32% iscomparable to the increase occurring from 950-1200 CE to 1700–
1850 CE (ca. 20–35%) (Figure 5).
Locally, the landscape openness around Lillsjön, the smalllake closest to the Gamlebyviken Bay, is large between 200–450
CE and 700–950 CE with a maximum of 45% already 200–450
CE (Roman Iron Age-Migration Period) which is comparable tothe local openness around Hyttegöl (42%) during the same time.
This early local openness is also comparable to the regional
openness 1700–1850 CE inferred from the pollen record of
Tjursbosjön (ca. 45%, Supplemental Figure S2.6, available
online) and larger than that from Storsjön (35%). The landscapeopenness around Lillsjön is also large during the Bronze Ageand Pre-Roman Iron Age (1150–50 BCE; 36% and 25%; Figure5). Moreover, the local landscape openness around both Lillsjön
and Hyttegöl 1700–1850 is very large, that is, 70% and 60%,
respectively, which is significantly larger than the regional
openness (35–45%). These results provide a strong indication of
the occurrence of large landscape openness, both regionally andlocally (at a few kilometer from the Gamlebyviken Bay), muchearlier than the 19th century, between 200–450 CE (Roman-Iron
Age-Migration Period) and 700–950 CE (Viking Age) in particular. Relatively large landscape openness is also indicatedduring the Bronze Age around Lillsjön, which agrees with the

The Holocene 34(1)interpretation of the archeological material in the study region
for this period.
We conclude from the above that land-use and land-coverchanges before the 19th century, during the Viking Age in particular but also during the Bronze Age and the Roman Iron Age, could
potentially have influenced the coastal waters (the Gamlebyviken
Bay in this case) through input of nutrients due to deforestationand extensive/intensive agricultural activities.
We summarize our results as follows. The pollen records from
Lillsjön and Hyttegöl provide two examples of cultural landscapehistory close to the Gamlebyviken Bay. The archeological datafrom the Lillsjön area indicate significant human activities
throughout the last 3000 years. Changes in the location of settlements and activities over time and space have influenced landscape openness locally in a similar way at Lillsjön and Hyttegöl
through the last 1700 years. The cover of open land was relatively
large (40–50%) ca. 200–450 CE (Early/Late Iron Age), lower(20–30%) ca. 450–1200 CE (Late Iron Age-Early Middle Ages),increased gradually to very large values (70–80%) ca. 1750–1850
CE, and decreased slightly (60–70%) until present. The regional
vegetation cover reconstructed from the pollen record of Storsjön
shows similar changes over the last 1500 years, although thecover of open land is smaller than at Hyttegöl from ca. 1200 CE
and Lillsjön from ca. 1450 CE. The landscape openness in the
Lillsjön area ca. 1150–0 BCE (Bronze Age-Early Iron Age) was
as large as ca. 450–950 CE (Late Iron Age), which is not the caseat the regional scale for which the cover of open land is lower
1150–0 BCE than 200–950 CE. There is no undisputable indication, neither in the archeological data nor in the pollen-based
reconstructions, of an impact of the Roman Warm Period, Medieval Warm Period and Little Ice Age on the human-induced landcover changes in the study region. Periods of afforestation,
regionally and/or locally, are better explained by socio-economical changes. Whether the short period of afforestation at Lillsjön
50 BCE–200 CE (Roman Iron Age and/or Migration Period) is
characteristic of the coastal region is not known and cannot be
confirmed with the archeological data available. This period
together with a second phase of afforestation 950–1450 CE
related to the expansion of spruce in the region are the times oflowest potential effect of local (and regional for the latest period)
landscape openness on coastal waters.
In terms of methodology issues, two points should be highlighted here. First, one must remember that both LOVE- and
REVEALS-based cover is always an overestimation in a geological context with a large proportion of exposed bedrock with novegetation, which is the case in our study region (Figure 1).
Therefore, increases in LOVE and REVEALS-based cover ofplants characteristic of open vegetation may not have been as
large as suggested by the pollen-based reconstructions. However,an increase in for example, grazing (inferred from pollen-based
REVEALS increase in pollen indicators of grazing) may also
have led to an increase in exposed bedrock, although it cannot bereconstructed from pollen data so far. A single attempt at reconstructing the past cover of bare ground using pollen data is available from a study in western China in which the modern analog
technique is combined with REVEALS reconstructions (Sunet al., 2022). Similar studies have not been attempted elsewhere in
the world so far. Second, the size of the bay’s catchment is muchlarger than the spatial scale of a LOVE land-cover reconstruction
but is smaller than the regional scale of a REVEALS reconstruction. To improve the representation of land-use and land-coverchange within the Gamlebyviken’s hydrological catchment area
in a pollen-based reconstruction, new studies should focus on pollen studies from a large lake located close to the center of thatcatchment area and several small lakes distributed within thatcatchment.

Vinogradova et al.

71

Acknowledgements
We are thankful to the Swedish Museum of Natural History andits personal, in particular Pia Östensson for providing an accessto the pollen reference collection, Johannes Bouchal and Anders
Amelin (†deceased) for assistance with laboratory work andIrena Hajdas for radiocarbon dating. We also thank the Department of Biology and Environment Science, Linnaeus University,
for providing laboratory facilities and chemicals for preparationof pollen samples and access to pollen reference collections andpollen identification literature. We are grateful to Siim Veski forvaluable discussion and suggestions on the study and improvements of the manuscript. Marie-José Gaillard acknowledges thefinancial support from the Faculty of Health and Life Sciences ofLinnaeus University and the Swedish Strategic Research Area
(SRA) MERGE (ModEling the Regional and Global Earth system). Olena Vinogradova is grateful to the School of Natural Science, Technology and Environmental Studies, Södertörn University, for financing radiocarbon dating.

Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The current study is a part of the SEASIDE-project fundedby the Foundation for Baltic and East European Studies (grant3146-3.1.1-2017).
Funding was provided to Martin Dahl by the Foundation for Baltic
and East European studies (grant number: 21-PD2-0002).

ORCID iDs
Olena Vinogradova

https://orcid.org/0000-0002-3147-9347

Christine Åkesson

https://orcid.org/0000-0002-1442-7019

Supplemental material
Supplemental material for this article is available online.

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