Late Holocene beetle assemblages and environmental change inGammelhemmet, northern Sweden

SARA KHORASANI, EVA PANAGIOTAKOPULU, ROGER ENGELMARK AND IAN RALSTON

Khorasani, S., Panagiotakopulu, E., Engelmark, R. & Ralston, I.: Late Holocene beetle assemblages andenvironmental change in Gammelhemmet, northern Sweden. Boreas. 10.1111/bor.12106. ISSN 0300-9483.

Analysis of insect fossil remains retrieved from a bog close to the abandoned farm at Gammelhemmet, nearLycksele in Swedish Lapland, enabled the reconstruction of environmental changes at the site over the last2500 years. These results represent the first late Holocene palaeoentomological succession studied for insectremains in the Västerbotten interior, and they provide new evidence for landscape change in the area. Around2000 years ago, at the end of the early Iron Age, disappearance of the tree and leaf litter fauna and an increase inaquatic species indicate the expansion of wetlands in the area. Patches of a multi-aged mixed woodland with adiverse assemblage of forest-dwelling beetles succeeded the wetland ∼1500 years ago, at the beginning of the lateIron Age. A marked change to open and drier conditions, and the presence of species often found in grassland andcultivated ground took place during the post-Medieval period. Our evidence indicates drainage of the area priorto the 18th century, placing the initiation of agricultural activities in Gammelhemmet earlier than the documen-tary record. Our research shows the potential of the use of fossil insects for understanding environmental changeand also human impact on the landscape, even of limited scale, from natural contexts.

Sara Khorasani and Eva Panagiotakopulu (corresponding author: eva.p@ed.ac.uk) School of GeoSciences,University of Edinburgh, Edinburgh EH8 9XP, UK; Roger Engelmark Historical, Philosophical and ReligiousStudies, Department of Archaeology, Umeå University, SE-901 87 Umeå, Sweden; Ian Ralston, School of History,Classics and Archaeology, University of Edinburgh, Edinburgh EH8 9AG, UK; received 5th May 2014, accepted24th August 2014.

During the late Holocene, northern Fennoscandia wasa landscape in which rapid changes were occurring as aresult of both natural processes and increasing humanimpacts. Climatic changes are apparent in thepalaeoecological record, in particular results from treerings, which indicate abrupt shifts in temperatureoccurring throughout the period (Eronen et al. 2002;Grudd et al. 2002). Some of these changes may havehad substantial impacts on the subsistence activities ofhuman groups in northern Sweden (Utterström 1955;Engelmark 1976; Broadbent 2010). Increasing humanexploitation throughout the late Holocene drovefurther changes in the boreal forests of northernFennoscandia, beginning with the earliest hunter-gatherer groups, whose activities would have includedthe removal of dead wood, ring-barking and felling oftrees for building materials and fuel (Hicks 1995;Hörnberg et al. 2005), bark peeling for food(Zackrisson et al. 2000), and possibly the use of fire topromote new growth to attract animals for hunting(Hörnberg et al. 1999). In the first millennium AD, inthe Iron Age (Table 1), as domestic reindeer were beingincreasingly employed as pack animals and as decoys inhunting, grazing and trampling altered the vegetationin and around settlement sites (Aronsson 1991; Hicks1995). In both Swedish and Finnish Lapland, it hasbeen demonstrated that past exploitation by indig-enous groups has resulted in changes in woodlandcover and composition, and the expansion of grassesand light-demanding herbaceous vegetation at severalsites (Aronsson 1991; Hicks 1993; Carpelan & Hicks1995; Hörnberg et al. 1999, 2005, 2014; Karlsson 2006).

Subtle indications for the use of pasture, andambiguous evidence of cultivation, can be seen alongthe river valleys of northern Sweden from the first mil-lennium AD (Engelmark 1978; Segerström 1990;Barnekow et al. 2008; Hörnberg et al. 2014), with moreconclusive evidence of settled farming from thepalaeoecological record from c. 525 cal. a BP(AD 1425) at the site of Arnemark north of the Piteriver (Hörnberg et al. 2014). At Lake Svartkälstjärn inVästerbotten, Barnekow et al. (2008) found Plantagolanceolata and a single grain of rye, Secale cereale,c. 300 cal. a BP (AD 1650). Earlier indications of openconditions in the area, recorded in the pollen recordc. 1500 cal. a BP (AD 450), are probably connectedwith reindeer herding (Barnekow et al. 2008). Only inthe late 17th century did settled farming begin inearnest in the interior regions of the north, encouragedby the Swedish state (Bylund 1956; Söderholm 1973).

In this framework, as part of a project examininglandscape change and interaction between indigenousgroups and incoming agriculturalists on the Arcticfringe, samples were collected close to the abandonedfarm at Gammelhemmet, in Västerbotten, nearLycksele (Fig. 1). The aims of the palaeoentomologicalresearch were to reconstruct late Holocene environ-mental and climate change in the area, looking for anyindications of anthropogenic change as a result of pas-toralism and settled agriculture from the Iron Age tothe post-Medieval period. This paper aims to fill a gapin palaeoentomological research from the region andpresents, in the light of data from otherpalaeoecological proxies (e.g. pollen, charcoal) from

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DOI 10.1111/bor.12106 © 2014 Collegium Boreas. Published by John Wiley & Sons Ltd

the area, the potential of the technique for recordingdetails of local change.

Previous research

Although northern Sweden is included in Coope andLemdahl’s discussions about climate reconstructionsbased on beetles, their temperature sensitivity and theuse of Mutual Climate Range (Coope et al. 1998;Coope & Lemdahl 1995, 1996), palaeoecologicalstudies of mid-late Holocene deposits in northernSweden are primarily based on pollen evidence. Apartfrom essentially casual early identifications (cf.Lindroth 1949), the first fossil insect study in the areawas undertaken by Carl Lindroth and Russell Coopefrom interglacial deposits at Leveäniemi in Norbotten

county (Lindroth & Coope 1971). The data fromLeveäniemi were a major advance in that they providedevidence that during the last interglacial, the Eemian,Lapland was the home for species that currently have amuch more southern distribution, suggesting a climateperhaps warmer than today (Lindroth & Coope 1971;see also Robertsson 2000). A study of small assem-blages from early Weichselian faunas from a group ofsites near Kiruna (e.g. Särkivuoma, Kurujärvi,Onttovaara), as well as sites in southern Sweden, waspublished by Lemdahl (1997a), who has also carriedout extensive studies of Lateglacial and Holocene sitesin the south of the country (Lemdahl 1997b). A singleanalysis of early to mid-Holocene insect fossil remainsfrom the Lapland interior was carried out by Buckland(2007) at Hemavan in the headwaters of the river Ume.

Coope’s early work on climate change was followedby studies by Lemdahl (cf. Lemdahl 1995, 1997a, b;Gaillard & Lemdahl 1994). This work was developedfurther with research in southern Sweden, which dem-onstrates environmental impact as a result of grazing,pastoral activities and farming. Grazing, fire and pos-sibly cultivation were indicated by fossil insects fromlate Holocene Stavsåkrain Småland (Olsson &Lemdahl 2009). The diversity of the landscape as aresult of human impact has also been shown in studiesof water sources within Iron Age settlements in south-central Sweden (Hellqvist 1999, 2014). On the basis ofinsect fossil remains from Medieval settlement depositsin Uppsala, Hellqvist & Lemdahl (1996) suggested achange in economic practice from a basis of crop cul-tivation to stock rearing in the 15th century, as well asimplying some evidence for climate change (Hellqvist &Lemdahl 1996).

Study site

The site of Gammelhemmet is situated ∼2 km south-west of the modern township of Knaften in LyckseleMunicipality, Lapland (64°25.95′N, 18°36.89′E;Fig. 1). Extensive wetlands and small lakes occur in thewider surroundings, within a topography of small,undulating hills. The Umeälven is located 17 km to theeast, whereas the smaller Öre river bounds the site800 m to the west. Cultivated land occurs along muchof the river today and virtually all areas of forest areintensively managed. The mixed coniferous-deciduousforest of the region is dominated by Scots pine (Pinussylvestris L.) whereas Norway spruce [Picea abies (L.)Karst.] occurs in areas of fine-grained, richer soils(Sjörs 1965; Kempe & von Segebaden 1990; Niklasson& Granström 2000). Deciduous trees include Betulapubescens Ehrh. and B. pendula Roth, Alnus, Populusand Salix spp., whereas Empetrum nigrum L., Callunavulgaris (L.) Hull., Vaccinium and Cladonia (Cladina)spp. are common components of the forest floor

Table 1. Archaeological chronological periods in Sweden during thelate Holocene (after Broadbent 2010).

Chronological periods in Sweden during the late Holocene

Medieval Period AD 1100–AD 1500Late Iron Age AD 400–AD 1100Early Iron Age 400 BC–AD 400Bronze Age 1800 BC–400 BCNeolithic 4500 BC–1800 BC

24°24°22°22°20°20°18°18°16°16°14°14° 26°26°

67º67º

68º68º

69º69º

NORWAYNORWAY

SWEDENSWEDEN

FINLANDFINLAND

HemavanHemavan

SkellefteåSkellefteå

GammelhemmetGammelhemmetLake SvartkälstjärnLake Svartkälstjärn

UmeåUmeå

64º64º

65º65º

66º66º

LuleåLuleå

Gulf of BothniaGulf of Bothnia

Leve niemiäLeve niemiä

International bordersInternational bordersProvincial boundariesProvincial boundariesRiversRiversSitesSitesModern citiesModern cities0 50 Km50 Km

N

KirunaKiruna

SärkivuomaSärkivuoma

KurujärviKurujärvi

OnttovaaraOnttovaara

Fig. 1. Location of Gammelhemmet in northern Sweden. Sites men-tioned in the text are indicated on the map. This figure is available incolour at http://www.boreas.dk.

2 Sara Khorasani et al. BOREAS

(Östlund et al. 1997). The climate is continental withmean January temperatures of −11 to −13°C and meanJuly temperatures of 13–15°C, with the first autumnfrosts occurring at the beginning of September and thelast frost at the start of June. The length of the growingseason is 140–150 days (Alexandersson & EggertssonKarlström 2001).

The area around Knaften is known to have beensettled during the period 1701–1749 (Bylund 1956). Thecensus shows a total of 13 people living in the area inthe year 1741 (Söderholm 1973), and the farm atGammelhemmet is present on a map of 1726(Lantmäteriet, map number Z16-110-1). The old farmis located in an area of flat, low-lying land to the west ofthe sampled bog (Fig. 2). An area roughly 200×150 msurrounds the remains of an old farm house, and isconsidered to have been cleared for hay production andpossibly cultivated (Riksantikvarieämbetet – SwedishNational Heritage Board 2005). Forty clearance cairnsand terrace ridges are recorded within this field and theremains of a wall provides a boundary. An irrigationchannel runs from close to the bog where samples weretaken towards the main farming area (Fig. 2). There isno indication when this feature was initially cut,

although such improvements were widespread inSweden in the 19th century (Emanuelsson & Moller1990).

Two other farms are recorded in the area, the set-tlement remains of Hemraningen to the north and theold agricultural area of Hedlägden to the south(Fig. 2). A saw-mill to the southeast may be con-nected with the farms, or with the intensification oflogging in the late 19th century (Östlund et al. 1997;Riksantikvarieämbetet – Swedish National HeritageBoard 2005). A wood tar pit possibly dates to the late18th − 19th century when management of the wood-land for potash and tar production occurred in someareas of Lycksele parish (Östlund et al. 1997;Nordlind & Östlund 2003). Two hunting pits lie to thenorth east of the site, and more extensive pit systemsexist along the Öre river. On the opposite side of theriver, ∼1 km to the southwest, a cluster of settlementremains ascribed to the Sámi have been recorded.Bronze Age burials and an undated reindeer pen arealso located within a radius of a few kilometres of thesite, along the river.

Methodology

Field sampling

The site is a small bog, ∼200×100 m, situated 150 mnortheast of the abandoned farm of Gammelhemmet at264 m a.s.l. The bog surface is dominated by a densemat of grasses, largely Poa alpina L., Danthoniadecumbens (L.) DC, Calamagrostis epigejos (L.) Rothand the sedges Carex lachenalii Schkuhr and Carexlapponica O. F. Lang, with abundant Sphagnum spp.and Polytrichum commune (s.l.). A field layer ofericaceous dwarf shrubs is dominated by Vacciniumvitis-idaea (L.). Shrubs of Betula nana L. and smallspruce and pine trees cover much of the bog. A thin veilof trees to the east separates the bog from the surround-ing landscape, which has recently been clear felled.Patchy woodland prevails to the west, whereas to thenorth a few standing snags, large solitary trees andseveral uprooted trees are found in an area of clearedwoodland.

A column of 10 samples, each of ∼5 L each, wastaken from the peat succession, reaching to a depth of65 cm where a silt/gravel substrate was encountered(Fig. 3). The surface layer was removed before sam-pling commenced. The sampling followed the stratigra-phy where possible. The upper 10 cm (S1) of the sectionconsisted of unhumified peat where plant material androotlets were evident. The following 20 cm of thesection (10–30 cm from the top of the sampled section;S2, S3) was characterized by dark brown, poorlyhumified, fibrous peat. The rest of the section washomogenous, consisting of dark brown peat thatincluded wood fragments. The top 30 cm was sampled

200 m200 m

Old fieldboundariesOld fieldboundariesIrrigationchannelIrrigationchannelRoadRoad

BogBog

RiverRiverContours(m a.s.l.)Contours(m a.s.l.)

Pitch pitPitch pit

FarmFarm

SawmillSawmillHedl gdenäHedl gdenä

GammelhemmetGammelhemmet

SampleSample

Hunting pitHunting pit

Hunting pitHunting pit

HemraningenHemraningen 353

toLy

ckse

le35

3 t o

Lyck

sele 307

307

295295

264264

250250

N

Fig. 2. Sample location map at Gammelhemmet. Data sourced fromRiksantikvarieämbetet - Swedish National Heritage Board (2005).This figure is available in colour at http://www.boreas.dk.

Late Holocene beetle assemblages and environmental change, N Sweden 3BOREAS

at intervals of 10 cm, whereas the remaining sampleswere then taken at 5-cm intervals.

Fossil insect analysis

Sample processing followed the method devised byCoope & Osborne (1968). Extraction of insect fossilremains was achieved by carefully disaggregating eachsample in warm water over a 300-μm sieve to removesilt. The residue was then left to drain. Paraffin (kero-sene) was mixed with the residue and cold water addedto allow the insect remains to float. The float wasretained on a 300-μm sieve and washed with detergentto eliminate traces of paraffin. This process of flotationwas repeated at least three times. The residue wasstored in ethanol before being sorted under a binocularmicroscope and identified with the aid of the Osbornecollection at the University of Edinburgh with refer-ence to relevant identification keys. All Coleopteraremains were identified to the lowest taxonomic levelpossible, preferably to species level, as this allows forthe most specific habitat reconstructions. Preservationof remains was generally good throughout the succes-sion. Fragmentation and some discoloration in thefragile elytra in a few cases (e.g. elytra of Coccinella sp.)did not allow identification to species level. Duringprocessing, fragments of wood were recovered from thelowermost sample, S10. No charcoal was found in thesamples. BugsCEP (Buckland & Buckland 2006) andadditional relevant references were used to collatehabitat information. The samples were compared usingdetrended correspondence analysis in the R computingprogram (Oksanen et al. 2008). Bugstats, a simplemodified Sørensen correlation coefficient built intoBugsCEP (Buckland 2007), was used as the basis forproducing an ecological diagram for the species recov-ered from Gammelhemmet. Raw numbers as opposedto percentages were used for the ecological diagram aswe think that they represent a more accurate picture ofthe ecology of the samples.

Radiocarbon dating

Plant macrofossil remains were extracted for 14Cdating. Accelerated mass spectrometry (AMS) datingwas performed at the Scottish Universities Environ-mental Research Centre (SUERC) laboratories in EastKilbride. Calibration was carried out using OxCal 4.1(Bronk Ramsey 2009). Identified seeds [Potentillapalustris (L.) Scop., Betula sp.], macrospores(Selaginella sp.) and a small birch twig (Betula sp.) werethe preferred materials owing to their short life spans.Problems of contamination with humic acid, which canbe affected by the transport of soluble organics throughthe sediment, were avoided by restricting the dating toshort-lived samples (Shore et al. 1995; Nilsson et al.2001). Four dates were successfully returned (Table 3,Fig. 3). The chronological succession observed throughthe profile is displayed by the age to depth model(Fig. 4). The basal sample (S10, 60–65 cm) date fromP. palustris seeds ranges from 2305±30 cal. a BP

665 cm

35 cm

55 cm

50 cm

45 cm

40 cm

25 cm

20 cm

15 cm

10 cm

5 cm

0 cm

60 cm

30 cm

S1

S2

S3

S5

S6

S7

S8

S9

S10

S4

Betula sp. twigAD 1446-1633

Betula sp. seedsAD 555-650

Potentillapalustris seeds408-233 BC

Selaginella sp.macrosporesPost bomb

Dark grey silt with gravelUnhumified peat

Partiallyhumified peat

Humified peatWood remains

Fig. 3. The sampled section at Gammelhemmet, showing the stratig-raphy of the section. Sampling every 5 cm for the larger part of thesection (S3−S10) and 10 cm for the three upper samples (S1−S3) isindicated. AMS 14C dates obtained from samples S1, S2, S6 and S10are also indicated next to the relevant samples.

4 Sara Khorasani et al. BOREAS

(408−233 BC), whereas the date from S6 (40–45 cm)from Betula seeds ranges from 1455±30 a BP (AD 555–650) (Table 2). The birch twig provided a date of375±30 a BP (AD 1446–1633) for S2 (10–20 cm).Dating of Selaginella macrospores from the upper10 cm suggests formation of this sample during thepost-bomb period (post-AD 1950) (Fig. 3). A depth toage model was constructed based on the dates obtained(Fig. 4) using the computer program CLAM (Blaauw2010). Humified peat in the lower part of the profile(S10−S4) is compressed, whereas in the upper part(S1−S3) the samples consist of poorly humifieduncompressed peat and this makes any attempt to cal-culate peat accumulation rates over time a difficulttask. In addition, peat cutting for structural turves andfuel has been practiced through most of the low Arctic(Maltby & Immirzi 1993; Franzén et al. 2012), and it isprobable that the upper part of the succession had beenremoved before the regrowth that yielded the recentdate. Exploitation of peatlands for agricultural pur-

poses was advised by the Royal Swedish Academy asearly as 1783 (Fleichner 1783) and clearing of thesurficial peat for this purpose could also provide anexplanation for the modern date obtained from S1.

Results

The results from the study of the Coleoptera fromGammelhemmet are summarized in Table 2. The tax-onomy follows Böhme (2005) and Gustafsson (2005).Gustafsson (2005) provided the main source ofinformation on current species distributions inFennoscandia. Information for species in Lapland isbased on Brundin (1934), whereas Nilsson & Holmen(1995) was the primary source for aquatic Coleopteraand Koch (1989a, b, 1992) was used for habitat data forStaphylinidae and other families of Coleoptera.

In the basal sample, S10, several beetles that aredependant on trees in both their adult and larval stagesare present (Table 3). The curculionid Deporaus betulae(L.) feeds on the leaves of Betula trees and shrubs, andoccasionally on Alnus and Corylus (Koponen &Nuorteva 1973), the larvae developing in leaf rolls onthe trees (Hoffmann 1954). Fen woodland and rivermargins are the preferred habitat of the willow beetlePhratora vulgatissima (L.), where it may occur in largenumbers feeding on the leaves of Salix and Populusbushes and trees growing on damp ground. Youngtrees in woodland clearings appear to be favoured bythe curculionid Phyllobius sp. in Scandinavia (Palm1996). In northern Sweden, the wood-boring weevil,Rhyncolus ater (L.) is recorded from deciduous trees,typically birch, as well as from conifers, attacking treesin various states of decay, mostly occurring in rottingwood where it creates distinctive galleries along thegrain (Palm 1951; Koponen & Nuorteva 1973). Theelaterid Denticollis linearis (L.) is omnivorous, occur-ring in rotten and fungus-infested wood as well as peatand moss litter (Alexander 2002); it has also been foundin a variety of closed forest environments (cf. Palm1959). Accompanying the woodland fauna in the basalsample is a wealth of litter- and moss-dwelling speciestypical of damp habitats; these include two species ofOlophrum, Lathrobium terminatum Grav. and Acidotacrenata (F.). Olophrum consimile (Gyll.) andO. rotundicolle (Sahl.) dwell amongst the litter of Salixscrub and alder carr and in the mosses and litter of wetbogs and stream margins (Campbell 1983).

20002000 15001500 10001000 500500

65656060

55555050

45454040

35353030

Dep

th (c

m)

Dep

th (c

m)

Age-depth modelAge-depth model

Age (cal. a. BP)Age (cal. a BP)

Fig. 4. Age-depth model from Gammelhemmet, obtained using thecomputer program CLAM (Blaauw 2010). The model is based ondates from Potentilla palustris (S10) and Betula sp. seeds (S6), and aBetula sp. twig (S2) (also see Fig. 3 and Table 1). The black line in thediagram represents calibrated radiocarbon dates and their error isindicated in blue/dark grey. This figure is available in colour at http://www.boreas.dk.

Table 2. AMS 14C dates from Gammelhemmet indicating material dated and relevant samples.

Depth (cm) Lab. code Material Uncal. (a BP) Cal. BC/AD (2σ) δ13C (‰)

0–10 (S1) SUERC-33486 Macrospores: Selaginella sp. 1.07±0.004 fraction modern Post-bomb −29.520–30 (S2) SUERC-33099 Twig: Betula sp. 375±30 AD 1446−1633 −29.440–45 (S6) SUERC-33485 Seeds: Betula sp. 1455±30 AD 555−650 −30.260–65 (S10) SUERC-33100 Seeds: Potentilla palustris (L.) Scop. 2305±30 408−233 BC −25.0

Late Holocene beetle assemblages and environmental change, N Sweden 5BOREAS

L. terminatum is typical of wetland biotopes and isoccasionally found in the leaf litter of Salix scrub (Lott& Anderson 2011). In Swedish Lapland, Acidotacrenata has been recorded from the vegetated ground

layer of birch woodland. Generally, this speciesappears to be attracted to rotting material in damp andshaded localities (Larsson & Gígja 1959; Campbell1982).

Table 3. Species list of Coleoptera from Gammelhemmet. The numbers represent minimum numbers of individuals (MNIs) for each sample.Radiocarbon dates for S1, S2, S6 and S10 and depths for all samples are indicated.

Sample number S1 S2 S3 S4 S5 S6 S7 S8 S9 S10Sample depth (cm) 0–10 10–20 20–30 30–35 30–35 40–45 45–50 50–55 55–60 60–65AMS 14C dates Post-bomb AD 1446–1633 AD 555–650 408–233 BC

TaxaColeopteraCarabidaeCarabidae indet. 1Patrobus assimilis Chaud. 1Pterostichus strenuus (Panz.) 1 1 1 2 2 1Calathus melanocephalus (L.) 1Agonum fuliginosum (Panz.) 1DytiscidaeDytiscidae indet. 1Hydroporus morio Aubé 4 1 1 2 1Hydroporus melanarius Sturm 2 1Hydroporus sp. 2 4 3HydrophilidaeAnacaena lutescens (Steph.) 3 1StaphylinidaeOlophrum consimile (Gyll.) 1 2 1Olophrum rotundicolle (Sahl.) 1 3 1 1 1 1 3 3Eucnecosum cf brachypterum (Grav.) 2 4 2 2 2 1 1Acidota crenata (F.) 1 1 2 1Stenus sp. 1 1 2 1 1Lathrobium rufipenne Gyll. 1 2Lathrobium terminatum Grav. 1 1 3 4 2 2 1 1 2Lathrobium (s.l.) spp. 1 3 2 2 1Cryptobium fracticorne (Payk.) 1 1 1 3 3 4Gabrius spp. 1 1 1 2 2Quedius spp. 1 1 2 3 2 1Mycetoporus sp. 1PselaphidaeBryaxis bulbifer (Reich.) 1 2 2 1ElateridaeElateridae indet. 1Ampedus nigrinus (Hbst.) 1Denticollis linearis (L.) 1CoccinellidaeCoccinella sp. 2 1 1 1ChrysomelidaePlateumaris discolor/sericea (Panz.)/(L.) 1Cryptocephalus labiatus (L.) 1Phratora vulgatissima (L.) 1 1Altica sp. 5 2 1 1 1Longitarsus sp. 3 1Chaetocnema hortensis (Geoff.) 1ScolytidaeHylurgops palliatus (Gyll.) 1Pityophthorus lichtensteini (Ratz.) 2Pityogenes bidentatus (Hbst.) 1 1CurculionidaeCurculionidae indet. 1Deporaus betulae (L.) 1Otiorhynchus nodosus (Müll.) 20 2 2 2 1 2Phyllobius sp. 1 1Strophosoma capitatum (Deg.) 1 1 1Rhyncolus ater (L.) 1 1 1Anthonomus phyllocola (Hbst.) 1 1

6 Sara Khorasani et al. BOREAS

Well-preserved remains of the chrysomelid Altica sp.were recovered from both S9 and S10. Only A. oleracea(L.) and A. chamaenerii (Lind.) are widespread inLapland, feeding largely on Onagraceae, probably thelocally ubiquitous Chamerion angustifolium (L.) Holub,Rosebay Willow-herb (Warchalowski 2003). In S9 fivespecies of Staphylinidae associated with damp environ-ments, Olophrum rotundicolle, Acidota crenata,Lathrobium terminatum, Cryptobium fracticorne andEucnecosum brachypterum, dominate the small assem-blage and the previous woodland fauna is absent.E. brachypterum enters the sequence here (S9) andremains prevalent until S3. This latter species is a rathereurytopic, largely cold stenothermic species, found in arange of rich meadows, heaths, bogs and grasslands, indeciduous woodlands and alongside rivers and lakes(Campbell 1984). It is known from plant litter andunder stones in a range of relatively open habitats inScandinavia (Østbye & Hågvar 1996). Hydroporusmorio Aubé is also present in S9, indicating the avail-ability of stagnant pools of water, characterized bySphagnum and Eriophorum (Böcher 1988). This speciesoften inhabits temporary pools in peaty bogs (Foster &Friday 2011).

The same species is present in S8, indicating the pres-ence of stagnant water. Species of Gabrius, also foundpredominantly in damp localities amongst plant debris(Backlund 1945; Larsson & Gígja 1959), are present,together with E. brachypterum, Lathrobium terminatum,L. rufipenne, O. consimile and O. rotundicolle. S8includes the pselaphid Bryaxis bulbifer (Reich.),common in the damp mosses and grasses of bogs, wetwoodlands and riparian habitats. Pityogenes bidentatus(Hbst.), a common scolytid of coniferous woodlands inScandinavia, is the only tree-dependent species in S8. Itis found in the branches of Picea and Pinus, often attack-ing the thinner areas of bark (Lekander et al. 1977). Alsopresent is Pterostichus strenuus, a ground beetle associ-ated with the litter layer of damp forests and meadowswith tall vegetation (Lindroth 1986).

The continued presence of H. morio indicates thatstagnant water pools still persist, and P. strenuus,O. rotundicolle, A. crenata and E. brachypterum arealso present in S7 as are Quedius spp. The latter inhabita diverse range of habitats, occurring in decaying plantmaterial, under tree bark, on fungi and commonly inbirds’ nests (Palm 1951, 1959), amongst other habitats.Cryptobium fracticorne (Payk.), found in mires anddamp heath grassland (Lott & Anderson 2011),appears in S7 and continues to be present for most ofthe rest of the succession, up to and including S3.

Strophosoma capitatum (Deg.), found in S7, andreappearing in S6 and S4, has been recorded in Scan-dinavia defoliating coniferous trees (Austarå et al.1984). Elsewhere in Europe however, it is more com-monly found in open environments amongst Callunavulgaris, the larvae feeding upon the roots (Morris

1997). S7 also introduces Longitarsus sp. to the specieslist. Members of this genus can be found in a range ofgrassland, open woodland and meadow environments.Unfortunately only elytra were found, in a poor state ofpreservation, precluding identification to species level.Species currently found in the Västerbotten areainclude those chiefly found feeding on plants in thefamily Asteraceae and also on Plantago. Stenus sp.,recorded from a range of wetland habitats, Coccinellasp., which feeds on aphids in pastures, woodland andheathland (Hyman 1992) and O. nodosus, a eurytopicweevil, found on open ground, under stones and inmosses, with a preference for soils with low moisturecontent (Mani 1968), are also present in the sample.

The assemblage from S6 has a suite of species,carabids, staphylinids, a coccinellid and curculionids,most of which are present in S7 (see Table 3). Theassemblage includes Hydroporus melanarius Sturm,which appears to favour peat-rich, mossy areas withinwoodland localities. Anthonomus phyllocola (Hbst) is aweevil associated with pine, the larvae developing incatkins and adults feeding upon the needles (Morris1977; Lindelöw & Björkman 2001); it is also foundoccasionally on Picea. It appears to be able to livewithin most types of habitat in which its host speciesflourishes, including bogs and heaths. Phyllobius sp.,which was present in the lowermost sample, S10, reap-pears in S6.

The assemblages found from S5 include most of thespecies found in the previous sample (with the excep-tion of A. phyllocola). Cryptocephalus labiatus (L.) ispresent from S5. It is known from river banks, bogs andlightly wooded heaths, where the larvae feed in the litterlayer beneath trees, constructing a generically distinc-tive protective ‘pot’ case of faeces; in northern Scandi-navia, the host plants are likely to be Betula and Salixspp.

S4 includes the same group of staphylinid species asearlier in the succession (see Table 2), with the additionof Gabrius. Bryaxis bulbifer, a predator on mites asso-ciated with damp environments is present in S4,together with increasing numbers of Altica sp. andLongitarsus sp. The chrysomelid Phratora vulgatissimawas recovered from S5 and S4 and the curculionidAnthonomus phyllocola was recovered from S4.Patrobus assimilis (Chaud.), a species generally foundin relatively open localities, including wet bogs charac-terized by sedges and Sphagnum mosses, or drier areasof shrub-scattered heathlands with ericaceous vegeta-tion (Lindroth 1985), is also present.

C. fracticorne and Gabrius sp. are the onlystaphylinids recovered from S3. Otiorhynchus nodosus(Müll.), a frequent but small component of thesequence until this point, becomes prevalent, with 20individuals from this sample. This flightless,polyphagous weevil feeds on a range of plants and isknown from various environments across its range

Late Holocene beetle assemblages and environmental change, N Sweden 7BOREAS

including bogs, meadows and light woodland.Chaetocnema hortensis (Geoff.) is a leaf beetle thatdevelops and feeds primarily on grasses, and is com-monly recorded in fields and meadows, in weedy placesand on arable land; its larvae develop in the stems ofPoaceae (Cox 2007). Calathus melanocephalus (L.) issimilarly known primarily from open grasslands(Lindroth 1986), fields and meadows, including areas ofcultivation, and in the north Atlantic region it appearsto favour dry and exposed areas (Larsson & Gígja1959; Lindroth et al. 1973). Ampedus nigrinus (Hbst)also appears in S3. It inhabits trees in varying states ofdecay including, red-rotted and mould ridden. Old ordead trees provide a suitable habitat for the develop-ment of its larvae, in particular pine, spruce and birch(Koponen & Nuorteva 1973), often in damp, boggyenvironments (Palm 1959). Both Koch (1989a) andPalm (1951, 1959) commented on its preference forbirches damaged by fire.

Sample 2 produced a very low number of specimens.The aquatics Hydroporus morio and Anacaena lutescens(Steph.) are present, the latter largely a beetle of acidiclocalities including stagnant or slow-moving waters(Hansen 1987). The reed beetle Plateumaris discolor(Panz.)/sericea (L.) is present in this sample only; bothspecies feed on waterside vegetation of Carex andEriophorum (Koch 1992). Pterostichus strenuus (Panz.)disappears from the sequence at this point, having beenpresent through S3–S8; it is rare in northern Sweden inthe present day (Lindroth 1986).

The staphylinid assemblage O. consimile, E.brachypterum, A. crenata, L. terminatum, C.

fracticorne and Quedius sp., the same suite of speciesas was noted earlier in the sequence, is present in S1,alongside Pityopthorus lichtensteini (Ratz.), commonlyfound in the thin twigs and branches of pine trees(Lekander et al. 1977), and Hylurgops palliatus(Gyll.), which is known from coniferous woodland,burrowing into the bark of moribund trees (idem).This species has been recorded within cut logs andstumps in areas affected by logging (Lekander et al.1977). In addition to Hydroporus morio, Agonumfuliginosum (Panz.), which is common in marshy areasshaded by vegetation and also in woodland environ-ments amongst ground mosses and leaf litter(Lindroth 1986), occurs in S1.

Discussion

Four successive phases (A, B, C and D) are observed inthe assemblages from Gammelhemmet, based onspecies composition and ecology.

Comparison of samples using detrended correspond-ence analysis (DCA) in R (Fig. 5) indicated that S8 andS9 show similarities in terms of their composition, andhave similarities with S10, the basal sample of thesection. S4, S5, S6 and S7 are also grouped together interms of their fauna. S2 and the uppermost sample, S1,demonstrate some degree of similarity. S3 indicates adifferent composition from all of the other samplesfrom the site. In terms of their chronology these fourphases span the early Iron Age to the modern period(see Table 1 and below).

−3 −2 −1 0 1 2 3 4

−2−1

01

23

DCA1

DC

A2

Pterostichus strenuus (Panz.)

Hydroporus melanarius SturmHydroporus sp.

Anacaena lutescens. (Steph.)

Olophrum consimile (Gyll.)Olophrum rotundicolle (Sahl.)

Eucnecosum brachypterum (Grav.)

Acidota crenata (F.)

Stenus sp.

Lathrobium rufipenne Gyll.

Lathrobium spp.

Cryptobium fracticorne (Payk.)

Gabrius spp.

Quedius spp.

Bryaxis bulbifer (Reich.)

Coccinella sp.

Phratora vulgatissima (L.)

Altica sp.Pityogenes bidentatus (Hbst.)

Otiorhynchus nodosus (Müll.)

Phyllobius sp.

Strophosoma capitatum (Deg.)

Anthonomus phyllocola (Hbst.)

Rhyncolus ater (L.)

Hydroporus morio Aubé

Patrobus assimilis Chaud.

Plateumaris discolor/sericea (Panz.)/(L.)

Carabidae indet.

Calathus melanocephalus (L.)

Agonum fuliginosum (Panz.)

Dytiscidae indet.

Mycetoporus sp.

Elateridae indet.Ampedus nigrinus (Hbst.)

Denticollis linearis (L.)

Cryptocephalus labiatus (L.)

Chaetocnema hortensis (Geof.)

Hylurgops palliatus (Gyll.)

Pityophthorus ichtensteini (Ratz.).

Deporaus betulae (L.)

S1

S2

S3

S7S4S5S6

S8S9

S10

Fig. 5. Comparison of samples usingdetrended correspondence analysis (DCA)in the computing program R (Oksanenet al. 2008). S9 and S8 are similar in termsof their species composition and there aresimilarities with the basal sample of thesection, S10. S4, S5, S6 and S7 are clus-tered together. S2 and S1 show somedegree of similarity. S3 indicates differ-ences in faunal composition from all ofthe other samples from theGammelhemmet section. This figure isavailable in colour at http://www.boreas.dk.

8 Sara Khorasani et al. BOREAS

The landscape change over time was summarized inan ecological habitat diagram based on beetle rawabundances in the samples and their habitat prefer-ences. This provides an overview of the site in terms ofits palaeoecology as inferred from the insect assem-blages (Fig. 6).

Phase A (S10−S8) – early Iron Age

In the basal sample of the succession, dated toc. 2305±30 a BP (408−233 BC), species found in old,rotting and dead wood reflect the mature woodlandprevailing in the area. The presence of beetle speciesfound on young trees, such as Deporaus betulae andPhratora vulgatissima, suggests that Betula, Alnus andSalix were growing in the lighter areas of woodland.Leaf litter and mosses covered the damp and shadedground, home to several hygrophilous staphylinids,including Olophrum consimile, Lathrobium terminatumand Acidota crenata, all of which can be found in dampand wet woodland localities. The assemblage reflects amulti-aged woodland with mature trees and accumula-tions of dead wood.

The woodland fauna starts reducing in S9, and thearea becomes more open and damp with an aquaticelement, demonstrating the formation of standingwater bodies in an increasingly boggy environment. Afew small shrubs and associated leaf litter may havebeen present. In the following samples, the groundfauna diversifies with the addition of severalstaphylinids including Quedius spp., Stenus sp. andC. fracticorne exploiting the damp vegetation in thedeveloping peat bog. Represented by only one scolytidin S8, Pityogenes bidentatus, coniferous woodland isstill present but perhaps receding to drier areas furtherfrom the bog.

Pollen evidence from a lake deposit at Svartkälstjärn(Fig. 1), some 50 km to the southeast ofGammelhemmet, indicates the onset of paludification,characterized by increased Sphagnum spores and anincrease in Picea sp. pollen, according to Barnekowet al. (2008), probably linked with colder and wetterconditions occurring in the region from c. 3500 cal. aBP. Further increases of Sphagnum alongsideCyperaceae occur at this site c. 2500 cal. a BP(Barnekow et al. 2008). Evidence of wet bog expansionat Gammelhemmet takes place around this time;however, the thermal tolerance limits of the beetles inthis part of the Gammelhemmet sequence do notprovide evidence that would indicate a change inclimate.

According to tree ring data, cold and wet conditionsappear to have prevailed in northern Sweden during thelatter part of the first millennium BC, with the timec. 2280 cal. a BP (330 BC) being particularly severe(Grudd et al. 2002). The soil profile at Gammelhemmetdisplays a change to less humified material in S8(Fig. 3), possibly indicative of wetter conditions (cf.Börgmark 2005).

Phase B (S7−S4) – late Iron Age and Medieval period

Larvae of the weevil Strophosoma capitatum, a speciesfrom S7, thrive in open areas, and its presence indicatesthat dry heathland comprised part of the wider land-

SamplesSamplesS1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 S8S8 S9S9 S10S10

Pasture /DungPasture /Dung0510152025

MeadowlandMeadowland0510152025

Wetlands/marshesWetlands/marshes

0510152025

Open wethabitatsOpen wethabitats

0510152025

Sandy/dry disturbed/arable

Sandy/dry disturbed/arable 0

510152025

Dung/foul habitatsDung/foul habitats

0510152025

Heathland& moorlandHeathland& moorland

0510152025

HalotolerantHalotolerant0510152025

SumRepSumRep0153045

AbundanceAbundance0

102030

NSpecNSpec0

10

20

AquaticsAquatics05

10152025

Standing waterStanding water

Wood and treesWood and trees

0510152025

DeciduousDeciduousConiferousConiferous

Fig. 6. Diagram showing ecological groupings according to specieshabitat preferences in each sample based on the diagram generated byBugstats in BugsCEP (Buckland & Buckland 2006). The group ofspecies associated with standing water within aquatic Coleoptera isindicated in blue. Within the category woodland, associations withconiferous woodland are noted with red and deciduous woodlandwith green. This figure is available in colour at http://www.boreas.dk.

Late Holocene beetle assemblages and environmental change, N Sweden 9BOREAS

scape. The diminution of the tree-dependent faunaindicates that the local woodland was adverselyaffected by the wet conditions developing in the imme-diate area. This is accompanied by the appearance ofspecies present in acidic, Sphagnum-dominated boghabitats, perhaps indicating the onset of mire forma-tion. Such changes can be encouraged by human activ-ity, including clear-cutting (e.g. Segerström &Emanuelsson 2002), which increases evapotranspira-tion, and also by climatic changes such as increasedprecipitation or lowered temperature (Charman 2002).

From S6, dated to around the mid-first millenniumAD, the fauna indicates the development of a mosaichabitat of woodland, lightly forested bog and patchesof dry heath. Remains of S. capitatum (recovered fromS7, S6 and S4) suggest the existence of both coniferouswoodland and Calluna shrubs. Many of the woodland-associated species recovered from this period are foundin light woodland clearings and heaths, suggesting thattree cover on the wet bog was a scattering of smallshrubs and young trees, perhaps with Salix in thewetter, nutrient-rich areas. This mosaic landscape ofpatchy forests and drier open areas in the surroundingsof the bog at Gammelhemmet contrasts with themature woodland inferred from the fauna recoveredfrom the basal sample.

According to Grudd et al. (2002), the first millen-nium AD was characterized by a warmer climateduring the first few centuries, followed by a cold periodaround AD 500–900 during the Late Iron Age.Rundgren (2008) discussed a shift to wetter conditionsin Västernorrland/Västerbotten around 1500 cal. a BPand stable hydrological conditions during the last700 years. However, with the data available it is diffi-cult to be certain that climate was the driver for bogexpansion to the detriment of woodland. In a recentdiscussion of pollen research from Arnemark, in PiteåKommun, Hörnberg et al. (2014) proposed thatgrazing and trampling linked with activities by localgroups were the reasons behind subtle changes seen inthe palynological results. At several sites associatedwith intermittent Sámi use, episodic land-use has beenproposed as a driver behind fluctuations in the treecover and the development of open, grassy and herb-rich areas (Aronsson 1991; Carpelan & Hicks 1995;Hörnberg et al. 2005; Karlsson 2006). As mentioned, inthe area of Gammelhemmet, the settlement to thesouthwest of the sampling site has been attributed tothe Sámi. If the surrounding forest was being exploitedby Sámi for wood, food and grazing as part of a hunter-herder economy, prior to the establishment of the farm,then the effects of such resource use could have influ-enced the local vegetation (cf. Josefsson et al. 2009,2014). The presence of hunting pits further indicateshuman presence in the landscape prior to the establish-ment of the farm, although the pits remain undated. Aseries of dates from hunting pits in Västerbotten shows

a concentration of use in the Iron Age and VikingPeriods (Holm 1992), and these pits are often found inassociation with Sámi remains (Mulk 1994). However,although the data imply human impact, there is notenough evidence in the insect fossil and archaeologicalrecord at Gammelhemmet to determine whether themosaic landscape structure seen at this time was strictlyassociated with human activity. The nature of impactson the landscape by the Sámi make it difficult, if notimpossible, to identify their footprint with any cer-tainty when the palaeoecological proxies lie outside ofactual settlement areas.

Phase C (S3) – early post-Medieval period

At the base of S3 the peat becomes poorly humified.This change in the stratigraphy is accompanied by achange in the faunal assemblage; S3 is markedly differ-ent in character from both the preceding and the fol-lowing samples (Figs 5, 6). The disappearance of theprevious woodland fauna and leaf litter species suggeststhe loss of the remaining shrubs and trees from the bogsurface. The local environment was open, as inferredfrom the species that inhabit grassland and cultivatedground, including Chaetocnema hortensis and Calathusmelanocephalus.

Considered alongside the appearance of dry grass-land species and the disappearance of most of the pre-vious hygrophilous staphylinids in S3, the increase innumbers of Otiorhynchus nodosus may indicate anexpansion of a drier habitat (Table 3). This species hasbeen recorded feeding on a range of plants includingRumex, a plant often growing in areas of disturbed,drier ground, and Trifolium spp., today species ofpasture and meadow environments. O. nodosus isflightless in its northern range, as is C. melanocephalus(Lindroth et al. 1973), suggesting that they have origi-nated from within the immediate area, probablymoving in immediately as appropriate habitat, openand disturbed areas, became available. Pterostichusstrenuus indicates that shaded conditions existed in thetall field grasses or the margins where the forest coverprevailed.

The elaterid Ampedus nigrinus, a beetle attracted tofire-damaged trees (Palm 1951, 1959; Koch 1989b), isfound in S3, alongside evidence of a change in environ-ment presumably associated with a farming settlement.In Scandinavia this species has been found both innatural Holocene forest deposits (Koponen &Nuorteva 1973; Olsson & Lemdahl 2009) and in LateHolocene samples associated with human activity(Olsson & Lemdahl 2009). Its presence in this part ofthe sequence at Gammelhemmet could be related tohuman exploitation of the forest, possibly using fire.Burning to clear land both permanently and as part ofswidden agriculture was widespread in northern Scan-dinavia (Sarmela 1987) and has been indicated in the

10 Sara Khorasani et al. BOREAS

palaeoecological evidence from Dalarna during estab-lishment of a grazing shieling (Segerström et al. 1996).

The insect assemblage is indicative of an increase inmeadow and reduction in wetlands (Fig. 6, Table 3),which are represented in all other samples from the site.The results from S3, with species that thrive on dry,open areas and indicate clearance, point to drainage ofthe area, perhaps in order to create land appropriate foragricultural activities. This provides evidence that theirrigation canal (Fig. 2) running from close to the bogtowards the main farming area may have been in usefrom this period to drain water from the bog. Althoughmanipulation of water levels within Västerbotten isgenerally considered a product of the 19th−20th centu-ries, the evidence from Gammelhemmet may place theorigins of the practice much earlier (Söderholm 1973;Zachrisson 1976; Östlund et al. 1997; Panagiotakopulu& Buckland 2012).

The AMS date from S3 places the assemblage priorto the 17th century AD, if not earlier (Table 2, Fig. 4),pre-dating the earliest records for settlement in the areain the early 18th century (Bylund 1956), something thatthe place name Gammelhemmet might also hint at. Amulti-proxy investigation by van der Linden et al.(2008) at Lappmyran, ∼50 km to the southeast (Fig. 1),also found increases in open, disturbed land and drymeadow from c. AD 1673 onwards. Further to thenortheast, a more open landscape is indicated bypalynology from Arnemark c. 300 cal. a BP (c. AD1650; Hörnberg et al. 2014). Although drainage of thewetland and an increase of meadow, perhaps more cor-rectly hayfield, is apparent, other farming practices,such as pasture management and crop production(Segerström et al. 1996; Östlund et al. 1997; Segerström& Emanuelsson 2002; Hörnberg et al. 2014), spreadingof farm waste as fertilizer (Wennberg 1985; Viklund1998) and peat cutting (Lundberg 2002), are not explic-itly witnessed in the insect fossil evidence fromGammelhemmet. In addition, it is equally challengingto link drainage activities with local groups as part ofpastoral intensification, or incomers, introducing agri-cultural innovation, although in view of the historicalrecord, the latter may be the more probable.

Phase D (S2−S1) – late post-Medieval tomodern period

The modern date obtained from S1 probably reflectsremoval of peat for structural turves and fuel, a tradi-tional practice in northern Sweden and subsequent peatregrowth at least during the last two centuries. The fewspecimens recovered from S1 and S2 indicate that thelocal environment began to revert to a wet bog, perhapsafter abandonment of the farm. Staphylinid species,such as Olophrum rotundicolle, Lathrobium terminatumand Gabrius spp. are present from S2, after their briefdisappearance from the section in S3 (where only

Cryptobium fracticorne remained). Aquatic species, e.g.Hydroporus morio and Anacaena lutescens, are present,alongside the reed beetle Plateumaris discolor/sericea,indicating the formation of standing water bodies in awet bog. Rhyncolus ater, a wood borer, has also beenrecovered from S2.

In S1 the terrestrial ground fauna expand in thediversifying wetland habitat and indicate a moss carpetinterspersed with sedges and grassy hummocks.H. morio accompanies peak numbers of Anacaenalutescens, revealing that the ground surface was becom-ing increasingly waterlogged. The natural wetland floraand fauna began to reinstate themselves during thistime, although the tree and shrub layer remainedsparse.

This may reflect a reduction in exploitation of thearea, allowing the return of the wetland fauna. Thehistorical records suggest that the site was abandonedbecause of severe frosts in the early 1800s, when thesettlers relocated to the modern village of Knaften(Riksantikvarieämbetet – Swedish National HeritageBoard 2005). A colder and wetter climate is known tohave prevailed at this time, towards the end of the LittleIce Age, in northern Sweden (Kullman & Kjällgren2000; Cowling et al. 2001; Grudd et al. 2002).

Three scolytid species are present in S1, indicatingthe existence of pine and spruce in the local area. Intheir study of the beetles in the dead wood of primevaland managed woodlands in Finland, Väisänen et al.(1993) recorded H. palliatus in abundance in themanaged forest only, and across Scandinavia thisspecies has been found not only in standing trees butalso in areas of logging (Lekander et al. 1977). Its pres-ence in S1, alongside other wood-dependent species,may reflect the recent forestry practices in the area. Theinsect fossil record suggests that birch does not featuresignificantly in the forest at this time.

The decline in deciduous species and prevalence ofeven-aged, single-storied pine and spruce dominatedforest is a pattern known from the region as a result ofmodern forestry practice over the last 100 years(Östlund et al. 1997). It is evident that a combination ofhuman activity, encouraging a change in tree composi-tion, and the later effects of forestry practices, hasshaped the woodland around the site today.

Conclusions

Using palaeoecological research in northern Sweden todifferentiate between climate change and humanimpact has several challenges. Although there is evi-dence for climate cooling from tree rings during differ-ent periods in the late Holocene (Grudd et al. 2002),depending on the context, it may be difficult to disen-tangle this from other aspects of the palaeocologicalrecord. In a landscape constantly modified by human

Late Holocene beetle assemblages and environmental change, N Sweden 11BOREAS

activity, it is often difficult to assign causes behind anychanges. The effects of pastoral activities by nomadicreindeer herders for example and limited clearance onthe landscape, where there is little evidence from char-coal, could be similar in terms of their palaeoecologicalsignal to subtle climate change, including increased firefrequency. By contrast, intensification and activitieslinked with settled agriculture, including introductionof invasive species, may leave a recognizable footprinton the fossil record and be evident in the modern land-scape and its trajectory.

Late Holocene environments in the interior parts ofthe Västerbotten region have a complex history ofhuman activity, shaped by indigenous Sámi and incom-ing settlers. Our results from insect fossils from thevicinity of the abandoned farm at Gammelhemmetdemonstrate that the local landscape has been shapedby the pressures of both natural and human-inducedchanges over the last 2500 years. The old conifer-dominated but mixed woodland in the area gave way toa wetland that was then succeeded by patches of wood-land and damp areas. With the exception of the initialdiminution of woodland on site, which could tenta-tively be linked to climate deterioration around thefourth century BC, there is little in the insect data tolink changes in the biodiversity of the faunas withclimate. If nothing else, the grouping of the assem-blages mirrors broad cultural phases with strong evi-dence for landscape modification during the early post-Medieval period.

In brief, the following events have been recognizedthrough the investigated palaeoenvironmental evidencefrom the insect fossils.

• A range of tree-dwelling species recovered in thebasal sample indicate that around the fourthcentury BC woodland prevailed in the area aroundGammelhemmet.

• The disappearance of the tree and leaf litter faunaand the dominance of wet bog species occur at thebeginning of the common era.

• A mosaic landscape consisting of open clearingsamongst the forest is demonstrated in the insectfossil record from around the mid-first millenniumAD.

• Around the 15th−17th centuries a change to moreopen conditions took place within the sampled area.

• The insect evidence indicates drainage of thewetland and an increase of meadow, pointing tofarming activities in the area during the post-Medieval period, probably prior to the early 18thcentury date postulated by literary record.

• During the modern period the insect fauna indicatesbog formation and coniferous forest in the area.

Further palaeoecological work from the area, fromnatural and archaeological contexts, will provide

detailed information for a better understanding of thetiming and the rates of environmental change. With thelate initiation of settled agriculture, there is an oppor-tunity to look into the impact of nomadic ortranshumant groups on their environments and tounderstand better and compare changes in biodiversityboth as a result of climate and different practices on thelandscape of northern Sweden.

Acknowledgements. – This work was financed by the LeverhulmeTrust as part of the project ‘Footsteps on the Edge of Thule: Land-scapes of Norse-indigenous interaction’, a grant awarded to the prin-cipal investigators, Kevin Edwards, University of Aberdeen, IanSimpson, University of Stirling, and Eva Panagiotakopulu andAndrew Dugmore, University of Edinburgh. Paul Buckland isthanked for his help in the field and useful comments. Thanks are alsodue to our colleagues from Umeå University, Phil Buckland, JohanLinderholm and Karen Viklund, for providing support for theproject in Sweden. Anastasios Panayiotakopoulos is thanked for hishelp in particular with the maps and section drawing. Permission touse the sample processing facilities at the Benthic Laboratory in theInstitute of Aquaculture, University of Stirling, is greatly appreci-ated. We would like to extend our gratitude to Geoffrey Lemdahl,Jan A. Piotrowski and an anonymous reviewer for their incisive andthoughtful comments, which have improved the paper.

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