Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870

Inger Greve Alsos; Youri Lammers; Sofia E. Kjellman; Marie Kristine Føreid Merkel; Emma M. Bender; Alexandra Rouillard; Egill Erlendsson; Esther Ruth Guðmundsdóttir; Ívar Örn Benediktsson; Wesley R. Farnsworth; Skafti Brynjólfsson; Guðrún Gísladóttir; Sigrún Dögg Eddudóttir; Anders Schomacker

doi:10.1016/j.quascirev.2021.106903

Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870

Inger Greve Alsos
, Youri Lammers
, Sofia E. Kjellman
, Marie Kristine Føreid Merkel
, Emma M. Bender
, Alexandra Rouillard
, Egill Erlendsson
, Esther Ruth Guðmundsdóttir
, Ívar Örn Benediktsson
, Wesley R. Farnsworth
, Skafti Brynjólfsson
, Guðrún Gísladóttir
, Sigrún Dögg Eddudóttir
, Anders Schomacker

University of Iceland

Research output: Contribution to journal › Article › peer-review

Abstract

Understanding patterns of colonisation is important for explaining both the distribution of single species and anticipating how ecosystems may respond to global warming. Insular flora may be especially vulnerable because oceans represent severe dispersal barriers. Here we analyse two lake sediment cores from Iceland for ancient sedimentary DNA to infer patterns of colonisation and Holocene vegetation development. Our cores from lakes Torfdalsvatn and Nykurvatn span the last c. 12,000 cal yr BP and c. 8600 cal yr BP, respectively. With near-centennial resolution, we identified a total of 191 plant taxa, with 152 taxa identified in the sedimentary record of Torfdalsvatn and 172 plant taxa in the sedimentary record of Nykurvatn. The terrestrial vegetation at Torfdalsvatn was initially dominated by bryophytes, arctic herbs such as Saxifraga spp. and grasses. Around 10,100 cal yr BP, a massive immigration of new taxa was observed, and shrubs and dwarf shrubs became common whereas aquatic macrophytes became dominant. At Nykurvatn, the dominant taxa were all present in the earliest samples; shrubs and dwarf shrubs were more abundant at this site than at Torfdalsvatn. There was an overall steep increase both in the local accumulated richness and regional species pool until 8000 cal yr BP, by which time ¾ of all taxa identified had arrived. The period 4500-1000 cal yr BP witnessed the appearance of a a small number of bryophytes, graminoids and forbs that were not recorded in earlier samples. The last millennium, after human settlement of the island (Landnám), is characterised by a sudden disappearance of Juniperus communis, but also reappearance of some high arctic forbs and dwarf shrubs. Notable immigration during the Holocene coincides with periods of increased incidence of sea ice, and we hypothesise that this may have acted as a dispersal vector. Thus, although ongoing climate change might provide a suitable habitat in Iceland for a large range of species only found in the neighbouring regions today, the reduction of sea ice may in fact limit the natural colonisation of new plant species.

Original language	English
Article number	106903
Journal	Quaternary Science Reviews
Volume	259
DOIs	https://doi.org/10.1016/j.quascirev.2021.106903
Publication status	Published - 1 May 2021

Bibliographical note

Funding Information: The initial steep increase in accumulated species richness at both sites represents an overestimation of colonisation at that time. For Torfdalsvatn, we know that many of the taxa were present earlier (Rundgren, 1995, 1998), and for Nykurvatn, our record does not include the earliest vegetation in the region. Thus, numerous species arrived prior to them being detected in our sedaDNA records (Figs. 8?9). Also, it takes time from the first arrival of a propagule to become spread around Iceland. Therefore, it is likely that the main phase of colonisation took place prior to 10,100 cal yr BP. Sea ice between Iceland and North Norway was common to dense prior to 11,000 cal yr BP (Alsos et al., 2016). In addition, catastrophic draining of the Baltic Ice Lake around 11,700 cal yr BP caused meltwater and potentially ice loaded with sediments to drift into the Nordic Seas (Bj?rck, 1995; Nesje et al., 2004). Both sea ice and drift ice have already been identified as a major dispersal vector for beetles to Iceland (Panagiotakopulu, 2014). After that, sea ice was only found occasionally around Iceland 11,000?8000 cal yr BP (Alsos et al., 2016), and may have been completely absent on the North Iceland shelf 11,700?6800 cal yr BP (Fig. 9, Xiao et al., 2017). This direct evidence of a massive immigration prior to 10,100 cal yr BP supports that sea ice may have acted as an important dispersal vector either by direct transport of diaspores or by a combination of wind and sea ice (Alsos et al., 2016; Panagiotakopulu, 2014). However, other vectors of dispersal such as birds, wind and sea currents may also have played an important role (Alsos et al., 2015).We would like to thank Lasse Topstad and Luca Elliott for help with DNA extraction, Dilli P. Rijal for help with R script for data analyses, and Ellen Elverland for help with identifying macrofossils. Claus Falkenberg Thomsen kindly assisted during fieldwork at Nykurvatn. Thorsteinn J?nsson and H?skuldur Thorbjarnarson assisted with coring at Torfdalsvatn. Kurt H. Kj?r and Marie-Louise Siggaard-Andersen, GLOBE Institute, kindly contributed with ITRAX sediment core scanning. Bioinformatic analyses were performed on resources provided by UNINETT Sigma2 - the National Infrastructure for High Performance Computing and Data Storage in Norway. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 819192 to Alsos), from the Arctic Research and Studies Program of the Ministries for Foreign Affairs of Norway and Iceland (grant agreement No. 2017-ARS-79772 to Schomacker), the Icelandic Research Fund (grant no. 141842-051; Gu?r?n G?slad?ttir), Landsvirkjun Energy Research Fund and the University of Iceland Research Fund. We thank two anonymous referees for constructive comments that improved the manuscript. Publisher Copyright: © 2021 The Authors

Other keywords

Ancient DNA
Colonisation
Holocene
Island
Lake sediments
Metabarcoding
Vegetation history

Access to Document

10.1016/j.quascirev.2021.106903

Cite this

Alsos, I. G., Lammers, Y., Kjellman, S. E., Merkel, M. K. F., Bender, E. M., Rouillard, A., Erlendsson, E., Guðmundsdóttir, E. R., Benediktsson, Í. Ö., Farnsworth, W. R., Brynjólfsson, S., Gísladóttir, G., Eddudóttir, S. D., & Schomacker, A. (2021). Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870. Quaternary Science Reviews, 259, Article 106903. https://doi.org/10.1016/j.quascirev.2021.106903

@article{523112c38b194130b0b7f61852a79037,

title = "Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landn{\'a}m) AD 870",

abstract = "Understanding patterns of colonisation is important for explaining both the distribution of single species and anticipating how ecosystems may respond to global warming. Insular flora may be especially vulnerable because oceans represent severe dispersal barriers. Here we analyse two lake sediment cores from Iceland for ancient sedimentary DNA to infer patterns of colonisation and Holocene vegetation development. Our cores from lakes Torfdalsvatn and Nykurvatn span the last c. 12,000 cal yr BP and c. 8600 cal yr BP, respectively. With near-centennial resolution, we identified a total of 191 plant taxa, with 152 taxa identified in the sedimentary record of Torfdalsvatn and 172 plant taxa in the sedimentary record of Nykurvatn. The terrestrial vegetation at Torfdalsvatn was initially dominated by bryophytes, arctic herbs such as Saxifraga spp. and grasses. Around 10,100 cal yr BP, a massive immigration of new taxa was observed, and shrubs and dwarf shrubs became common whereas aquatic macrophytes became dominant. At Nykurvatn, the dominant taxa were all present in the earliest samples; shrubs and dwarf shrubs were more abundant at this site than at Torfdalsvatn. There was an overall steep increase both in the local accumulated richness and regional species pool until 8000 cal yr BP, by which time ¾ of all taxa identified had arrived. The period 4500-1000 cal yr BP witnessed the appearance of a a small number of bryophytes, graminoids and forbs that were not recorded in earlier samples. The last millennium, after human settlement of the island (Landn{\'a}m), is characterised by a sudden disappearance of Juniperus communis, but also reappearance of some high arctic forbs and dwarf shrubs. Notable immigration during the Holocene coincides with periods of increased incidence of sea ice, and we hypothesise that this may have acted as a dispersal vector. Thus, although ongoing climate change might provide a suitable habitat in Iceland for a large range of species only found in the neighbouring regions today, the reduction of sea ice may in fact limit the natural colonisation of new plant species.",

keywords = "Ancient DNA, Colonisation, Holocene, Island, Lake sediments, Metabarcoding, Vegetation history",

author = "Alsos, \{Inger Greve\} and Youri Lammers and Kjellman, \{Sofia E.\} and Merkel, \{Marie Kristine F{\o}reid\} and Bender, \{Emma M.\} and Alexandra Rouillard and Egill Erlendsson and Gu{\dh}mundsd{\'o}ttir, \{Esther Ruth\} and Benediktsson, \{{\'I}var {\"O}rn\} and Farnsworth, \{Wesley R.\} and Skafti Brynj{\'o}lfsson and Gu{\dh}r{\'u}n G{\'i}slad{\'o}ttir and Eddud{\'o}ttir, \{Sigr{\'u}n D{\"o}gg\} and Anders Schomacker",

note = "Funding Information: The initial steep increase in accumulated species richness at both sites represents an overestimation of colonisation at that time. For Torfdalsvatn, we know that many of the taxa were present earlier (Rundgren, 1995, 1998), and for Nykurvatn, our record does not include the earliest vegetation in the region. Thus, numerous species arrived prior to them being detected in our sedaDNA records (Figs. 8?9). Also, it takes time from the first arrival of a propagule to become spread around Iceland. Therefore, it is likely that the main phase of colonisation took place prior to 10,100 cal yr BP. Sea ice between Iceland and North Norway was common to dense prior to 11,000 cal yr BP (Alsos et al., 2016). In addition, catastrophic draining of the Baltic Ice Lake around 11,700 cal yr BP caused meltwater and potentially ice loaded with sediments to drift into the Nordic Seas (Bj?rck, 1995; Nesje et al., 2004). Both sea ice and drift ice have already been identified as a major dispersal vector for beetles to Iceland (Panagiotakopulu, 2014). After that, sea ice was only found occasionally around Iceland 11,000?8000 cal yr BP (Alsos et al., 2016), and may have been completely absent on the North Iceland shelf 11,700?6800 cal yr BP (Fig. 9, Xiao et al., 2017). This direct evidence of a massive immigration prior to 10,100 cal yr BP supports that sea ice may have acted as an important dispersal vector either by direct transport of diaspores or by a combination of wind and sea ice (Alsos et al., 2016; Panagiotakopulu, 2014). However, other vectors of dispersal such as birds, wind and sea currents may also have played an important role (Alsos et al., 2015).We would like to thank Lasse Topstad and Luca Elliott for help with DNA extraction, Dilli P. Rijal for help with R script for data analyses, and Ellen Elverland for help with identifying macrofossils. Claus Falkenberg Thomsen kindly assisted during fieldwork at Nykurvatn. Thorsteinn J?nsson and H?skuldur Thorbjarnarson assisted with coring at Torfdalsvatn. Kurt H. Kj?r and Marie-Louise Siggaard-Andersen, GLOBE Institute, kindly contributed with ITRAX sediment core scanning. Bioinformatic analyses were performed on resources provided by UNINETT Sigma2 - the National Infrastructure for High Performance Computing and Data Storage in Norway. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 819192 to Alsos), from the Arctic Research and Studies Program of the Ministries for Foreign Affairs of Norway and Iceland (grant agreement No. 2017-ARS-79772 to Schomacker), the Icelandic Research Fund (grant no. 141842-051; Gu?r?n G?slad?ttir), Landsvirkjun Energy Research Fund and the University of Iceland Research Fund. We thank two anonymous referees for constructive comments that improved the manuscript. Publisher Copyright: {\textcopyright} 2021 The Authors",

year = "2021",

month = may,

day = "1",

doi = "10.1016/j.quascirev.2021.106903",

language = "English",

volume = "259",

journal = "Quaternary Science Reviews",

issn = "0277-3791",

publisher = "Elsevier Ltd.",

}

Alsos, IG, Lammers, Y, Kjellman, SE, Merkel, MKF, Bender, EM, Rouillard, A, Erlendsson, E , Guðmundsdóttir, ER , Benediktsson, ÍÖ , Farnsworth, WR, Brynjólfsson, S, Gísladóttir, G, Eddudóttir, SD & Schomacker, A 2021, 'Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870', Quaternary Science Reviews, vol. 259, 106903. https://doi.org/10.1016/j.quascirev.2021.106903

TY - JOUR

T1 - Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870

AU - Alsos, Inger Greve

AU - Lammers, Youri

AU - Kjellman, Sofia E.

AU - Merkel, Marie Kristine Føreid

AU - Bender, Emma M.

AU - Rouillard, Alexandra

AU - Erlendsson, Egill

AU - Guðmundsdóttir, Esther Ruth

AU - Benediktsson, Ívar Örn

AU - Farnsworth, Wesley R.

AU - Brynjólfsson, Skafti

AU - Gísladóttir, Guðrún

AU - Eddudóttir, Sigrún Dögg

AU - Schomacker, Anders

N1 - Funding Information: The initial steep increase in accumulated species richness at both sites represents an overestimation of colonisation at that time. For Torfdalsvatn, we know that many of the taxa were present earlier (Rundgren, 1995, 1998), and for Nykurvatn, our record does not include the earliest vegetation in the region. Thus, numerous species arrived prior to them being detected in our sedaDNA records (Figs. 8?9). Also, it takes time from the first arrival of a propagule to become spread around Iceland. Therefore, it is likely that the main phase of colonisation took place prior to 10,100 cal yr BP. Sea ice between Iceland and North Norway was common to dense prior to 11,000 cal yr BP (Alsos et al., 2016). In addition, catastrophic draining of the Baltic Ice Lake around 11,700 cal yr BP caused meltwater and potentially ice loaded with sediments to drift into the Nordic Seas (Bj?rck, 1995; Nesje et al., 2004). Both sea ice and drift ice have already been identified as a major dispersal vector for beetles to Iceland (Panagiotakopulu, 2014). After that, sea ice was only found occasionally around Iceland 11,000?8000 cal yr BP (Alsos et al., 2016), and may have been completely absent on the North Iceland shelf 11,700?6800 cal yr BP (Fig. 9, Xiao et al., 2017). This direct evidence of a massive immigration prior to 10,100 cal yr BP supports that sea ice may have acted as an important dispersal vector either by direct transport of diaspores or by a combination of wind and sea ice (Alsos et al., 2016; Panagiotakopulu, 2014). However, other vectors of dispersal such as birds, wind and sea currents may also have played an important role (Alsos et al., 2015).We would like to thank Lasse Topstad and Luca Elliott for help with DNA extraction, Dilli P. Rijal for help with R script for data analyses, and Ellen Elverland for help with identifying macrofossils. Claus Falkenberg Thomsen kindly assisted during fieldwork at Nykurvatn. Thorsteinn J?nsson and H?skuldur Thorbjarnarson assisted with coring at Torfdalsvatn. Kurt H. Kj?r and Marie-Louise Siggaard-Andersen, GLOBE Institute, kindly contributed with ITRAX sediment core scanning. Bioinformatic analyses were performed on resources provided by UNINETT Sigma2 - the National Infrastructure for High Performance Computing and Data Storage in Norway. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 819192 to Alsos), from the Arctic Research and Studies Program of the Ministries for Foreign Affairs of Norway and Iceland (grant agreement No. 2017-ARS-79772 to Schomacker), the Icelandic Research Fund (grant no. 141842-051; Gu?r?n G?slad?ttir), Landsvirkjun Energy Research Fund and the University of Iceland Research Fund. We thank two anonymous referees for constructive comments that improved the manuscript. Publisher Copyright: © 2021 The Authors

PY - 2021/5/1

Y1 - 2021/5/1

N2 - Understanding patterns of colonisation is important for explaining both the distribution of single species and anticipating how ecosystems may respond to global warming. Insular flora may be especially vulnerable because oceans represent severe dispersal barriers. Here we analyse two lake sediment cores from Iceland for ancient sedimentary DNA to infer patterns of colonisation and Holocene vegetation development. Our cores from lakes Torfdalsvatn and Nykurvatn span the last c. 12,000 cal yr BP and c. 8600 cal yr BP, respectively. With near-centennial resolution, we identified a total of 191 plant taxa, with 152 taxa identified in the sedimentary record of Torfdalsvatn and 172 plant taxa in the sedimentary record of Nykurvatn. The terrestrial vegetation at Torfdalsvatn was initially dominated by bryophytes, arctic herbs such as Saxifraga spp. and grasses. Around 10,100 cal yr BP, a massive immigration of new taxa was observed, and shrubs and dwarf shrubs became common whereas aquatic macrophytes became dominant. At Nykurvatn, the dominant taxa were all present in the earliest samples; shrubs and dwarf shrubs were more abundant at this site than at Torfdalsvatn. There was an overall steep increase both in the local accumulated richness and regional species pool until 8000 cal yr BP, by which time ¾ of all taxa identified had arrived. The period 4500-1000 cal yr BP witnessed the appearance of a a small number of bryophytes, graminoids and forbs that were not recorded in earlier samples. The last millennium, after human settlement of the island (Landnám), is characterised by a sudden disappearance of Juniperus communis, but also reappearance of some high arctic forbs and dwarf shrubs. Notable immigration during the Holocene coincides with periods of increased incidence of sea ice, and we hypothesise that this may have acted as a dispersal vector. Thus, although ongoing climate change might provide a suitable habitat in Iceland for a large range of species only found in the neighbouring regions today, the reduction of sea ice may in fact limit the natural colonisation of new plant species.

AB - Understanding patterns of colonisation is important for explaining both the distribution of single species and anticipating how ecosystems may respond to global warming. Insular flora may be especially vulnerable because oceans represent severe dispersal barriers. Here we analyse two lake sediment cores from Iceland for ancient sedimentary DNA to infer patterns of colonisation and Holocene vegetation development. Our cores from lakes Torfdalsvatn and Nykurvatn span the last c. 12,000 cal yr BP and c. 8600 cal yr BP, respectively. With near-centennial resolution, we identified a total of 191 plant taxa, with 152 taxa identified in the sedimentary record of Torfdalsvatn and 172 plant taxa in the sedimentary record of Nykurvatn. The terrestrial vegetation at Torfdalsvatn was initially dominated by bryophytes, arctic herbs such as Saxifraga spp. and grasses. Around 10,100 cal yr BP, a massive immigration of new taxa was observed, and shrubs and dwarf shrubs became common whereas aquatic macrophytes became dominant. At Nykurvatn, the dominant taxa were all present in the earliest samples; shrubs and dwarf shrubs were more abundant at this site than at Torfdalsvatn. There was an overall steep increase both in the local accumulated richness and regional species pool until 8000 cal yr BP, by which time ¾ of all taxa identified had arrived. The period 4500-1000 cal yr BP witnessed the appearance of a a small number of bryophytes, graminoids and forbs that were not recorded in earlier samples. The last millennium, after human settlement of the island (Landnám), is characterised by a sudden disappearance of Juniperus communis, but also reappearance of some high arctic forbs and dwarf shrubs. Notable immigration during the Holocene coincides with periods of increased incidence of sea ice, and we hypothesise that this may have acted as a dispersal vector. Thus, although ongoing climate change might provide a suitable habitat in Iceland for a large range of species only found in the neighbouring regions today, the reduction of sea ice may in fact limit the natural colonisation of new plant species.

KW - Ancient DNA

KW - Colonisation

KW - Holocene

KW - Island

KW - Lake sediments

KW - Metabarcoding

KW - Vegetation history

UR - https://www.scopus.com/pages/publications/85103787832

U2 - 10.1016/j.quascirev.2021.106903

DO - 10.1016/j.quascirev.2021.106903

M3 - Article

SN - 0277-3791

VL - 259

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

M1 - 106903

ER -

Ancient sedimentary DNA shows rapid post-glacial colonisation of Iceland followed by relatively stable vegetation until the Norse settlement (Landnám) AD 870

Abstract

Bibliographical note

Other keywords

Access to Document

Fingerprint

Cite this