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  • 1.
    Andren, Elinor
    et al.
    Sodertom Univ, Sch Nat Sci Technol & Environm Studies, Huddinge, Sweden..
    Klimaschewski, Andrea
    Queens Univ Belfast, Sch Geog Archaeol & Palaeoecol, Belfast BT7 1NN, Antrim, North Ireland..
    Self, Angela E.
    Nat Hist Museum, Dept Life Sci, London SW7 5BD, England..
    Amour, Natalie St.
    Univ Western Ontario, Dept Earth Sci, London, ON, Canada..
    Andreev, Andrei A.
    Univ Cologne, Inst Geol & Mineral, D-50931 Cologne, Germany.;Kazan Fed Univ, Inst Geol & Petr Technol, Kazan, Russia..
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Queens Univ Belfast, Sch Geog Archaeol & Palaeoecol, Belfast BT7 1NN, Antrim, North Ireland..
    Conley, Daniel J.
    Lund Univ, Dept Geol, Quaternary Sci, Lund, Sweden..
    Edwards, Thomas W. D.
    Univ Waterloo, Dept Earth & Environm Sci, Waterloo, ON N2L 3G1, Canada..
    Solovieva, Nadia
    Kazan Fed Univ, Inst Geol & Petr Technol, Kazan, Russia.;UCL, Dept Geog, London WC1E 6BT, England..
    Harnmarlund, Dan
    Lund Univ, Dept Geol, Quaternary Sci, Lund, Sweden..
    Holocene climate and environmental change in north-eastern Kamchatka (Russian Far East), inferred from a multi-proxy study of lake sediments2015In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 134, p. 41-54Article in journal (Refereed)
    Abstract [en]

    A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well as responses of the lake ecosystern to catchment maturity and multiple stressors, such as climate change and volcanic eruptions. Climate change is the major driving force resulting in the recorded environmental changes in the lake, although recurrent tephra deposition events also contributed. The sediment record has an age at the base of about 10,000 cal yrs BP, and during the first 400 years the climate was cold and the lake exhibited extensive ice-cover during winter and relatively low primary production. Soils in the catchment were poor with shrub alder and birches dominating the vegetation surrounding the lake. At about 9600-8900 cal yrs BP the climate was cold and moist, and strong seasonal wind stress resulted in reduced ice-cover and increased primary production. After ca. 8900 cal yrs BP the forest density increased around the lake, runoff decreased in a generally drier climate resulting in decreased primary production in the lake until ca. 7000 cal yrs BP. This generally dry climate was interrupted by a brief climatic perturbation, possibly attributed to the 8.2 ka event, indicating increasingly windy conditions with thick snow cover, reduced ice-cover and slightly elevated primary production in the lake. The diatom record shows maximum thermal stratification at ca. 6300-5800 cal yrs BP and indicates together with the geochemical proxies a dry and slightly warmer climate resulting in a high productive lake. The most remarkably change in the catchment vegetation occurred at ca. 4200 cal yrs BP in the form of a conspicuous increase in Siberian dwarf pine (Pinus pumila), indicating a shift to a cooler climate with a thicker and more long-lasting snow cover. This vegetational change was accompanied by marked shifts in the diatom and chironomid stratigraphies, which are also indicative of colder climate and more extensive ice-cover.

  • 2.
    Bennett, Keith
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Interpretation of pollen data from southern Chile and climate change at the last glacial/interglacial transition2003Conference paper (Other (popular scientific, debate etc.))
  • 3.
    Bennett, Keith
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    Out of Australasia?2004In: Quaternary Australasia, Vol. 22, no 1, p. 5-7Article in journal (Other scientific)
  • 4.
    Bennett, Keith
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    The movement of plants in space and time2004Conference paper (Other (popular scientific, debate etc.))
  • 5.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Comment on "Sedimentary DNA from a submerged site reveals wheat in the British Isles 8000 years ago"2015In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 349, no 6245Article in journal (Other academic)
    Abstract [en]

    Smith et al. (Reports, 27 February 2015, p. 998) identify wheat DNA from an 8000-calendar-years-before-the-present archaeological site in southern England and conclude that wheat was traded to Britain 2000 years before the arrival of agriculture. The DNA samples are not dated, either directly or from circumstantial evidence, so there is no chronological evidence to support the claim.

  • 6.
    Bennett, Keith D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Bhagwat, S. A.
    Willis, K. J.
    Neotropical refugia2012In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 22, no 11, p. 1207-1214Article in journal (Refereed)
    Abstract [en]

    Patterns of endemism in the Neotropics have been explained by restriction of forest to 'refugia' in arid cold-stages of the Quaternary (Haffer J (1969) Speciation in Amazonian forest birds. Science 165: 131-137). The palaeoecological record, however, shows no such forest contraction. We review palaeoecological and phylogenetic data on the response of Neotropical taxa and communities to climatic changes of the Cenozoic. Solar insolation varies over this period with latitude and geography, including shifts in opposite directions between high and low latitudes. In the Neotropics, distribution and abundance patterns originate on a wide range of timescales through the Cenozoic, down to the currently dominant precession forcing (20 kyr). In contrast, distributions and abundances at higher latitudes are controlled by obliquity forcing (40 kyr). The patterns observed by Haffer (1969) are likely derived from pre-Quaternary radiations and are not inconsistent with palaeoecological findings of continuous forest cover in major areas of the Neotropics during the Quaternary. The relative proportions of speciation processes have changed through time between predominantly sympatric to predominantly allopatric depending on the prevailing characteristics of orbitally forced climatic changes. Behaviour of Neotropical organisms and ecosystems on long timescales may be influenced much more by precessional forcing than by the obliquity forcing that controls high-latitude climate change and glaciations.

  • 7.
    Bennett, Keith D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Functional Genomics.
    Parducci, Laura
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Functional Genomics.
    DNA from pollen: principles and potential2006In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 16, no 8, p. 1031-1034Article in journal (Refereed)
    Abstract [en]

    This paper describes our recent extraction of ancient DNA (aDNA) from Holocene pollen and discusses the potential of the technique for elucidating timescales of evolutionary change. We show that plastid DNA is recoverable and usable from pollen grains of Scots pine Pinus sylvestris from 10 ka and 100 years ago. Comparison of the ancient sequences with modern sequences, obtained from an extant population, establish a first genetic link between modern and fossil samples of Scots pine, providing a genetic continuity through time. One common haplotype is present in each of the three periods investigated, suggesting that it persisted near the lake throughout the postglacial. The retrieval of aDNA from pollen has major implications for palaeoecology by allowing (i) investigation of population-level dynamics in time and space, and (ii) tracing ancestry of populations and developing phylogenetic trees that include extinct as well as extant taxa. The method should work over the last glacial oscillation, thus giving access to ancestry of populations over a crucial period of time for the understanding of the relationship between speciation and climate change.

  • 8.
    Bennett, Keith
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Fuller, Janice
    The mid-Holocene Tsuga canadensis (hemlock) decline, eastern North America — age versus causes: a reply to Payette2004In: The Holocene, Vol. 14, no 6, p. 950-951Article in journal (Refereed)
  • 9.
    Bennett, Keith
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Haberle, Simon
    Holocene spread of forest trees in southern Chile2004Conference paper (Other (popular scientific, debate etc.))
  • 10.
    Bennett, Keith
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    Hicks, Sheila
    Numerical analysis of surface and fossil pollen spectra from northern Fennoscandia2005In: Journal of Biogeography, Vol. 32, p. 407-423Article in journal (Refereed)
  • 11.
    Blaauw, Maarten
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    Christen, J. Andres
    van der Plicht, J.
    Bennett, Keith
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    21st century suck-in or smear: testing the timing of events between archives2006In: PAGES News, Vol. 14, no 3, p. 15-16Article in journal (Other (popular scientific, debate etc.))
  • 12. de Boer, Erik J.
    et al.
    Hooghiemstra, Henry
    Florens, F. B. Vincent
    Baider, Claudia
    Engels, Stefan
    Dakos, Vasilis
    Blaauw, Maarten
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Rapid succession of plant associations on the small ocean island of Mauritius at the onset of the Holocene2013In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 68, p. 114-125Article in journal (Refereed)
    Abstract [en]

    The island of Mauritius offers the opportunity to study the poorly understood vegetation response to climate change on a small tropical oceanic island. A high-resolution pollen record from a 10 m long peat core from Kanaka Crater (560 m elevation, Mauritius, Indian Ocean) shows that vegetation shifted from a stable open wet forest Last Glacial state to a stable closed-stratified-tall-forest Holocene state. An ecological threshold was crossed at similar to 11.5 cal ka BP, propelling the forest ecosystem into an unstable period lasting similar to 4000 years. The shift between the two steady states involves a cascade of four abrupt (<150 years) forest transitions in which different tree species dominated the vegetation for a quasi-stable period of respectively similar to 1900, similar to 1100 and similar to 900 years. We interpret the first forest transition as climate-driven, reflecting the response of a small low topography oceanic island where significant spatial biome migration is impossible. The three subsequent forest transitions are not evidently linked to climate events, and are suggested to be driven by internal forest dynamics. The cascade of four consecutive events of species turnover occurred at a remarkably fast rate compared to changes during the preceding and following periods, and might therefore be considered as a composite tipping point in the ecosystem. We hypothesize that wet gallery forest, spatially and temporally stabilized by the drainage system, served as a long lasting reservoir of biodiversity and facilitated a rapid exchange of species with the montane forests to allow for a rapid cascade of plant associations.

  • 13. Fontana, S. L.
    et al.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Postglacial vegetation dynamics of western Tierra del Fuego2012In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 22, no 11, p. 1337-1350Article in journal (Refereed)
    Abstract [en]

    The southern fringes of the South American landmass provide a rare opportunity to examine the development of moorland vegetation with sparse tree cover in a wet, cool temperate climate of the Southern Hemisphere. We present a record of changes in vegetation over the past 17,000 years, from a lake in extreme southern Chile (Isla Santa Inés, Magallanes region, 53°38.97S; 72°25.24W), where human influence on vegetation is negligible. The western archipelago of Tierra del Fuego remained treeless for most of the Lateglacial period; Lycopodium magellanicum, Gunnera magellanica and heath species dominated the vegetation. Nothofagus may have survived the last glacial maximum at the eastern edge of the Magellan glaciers from where it spread southwestwards and established in the region at around 10,500 cal. yr BP. Nothofagus antarctica was likely the earlier colonizing tree in the western islands, followed shortly after by Nothofagus betuloides. At 9000 cal. yr BP moorland communities expanded at the expense of Nothofagus woodland. Simultaneously, Nothofagus species shifted to dominance of the evergreen Nothofagus betuloides and the Magellanic rain forest established in the region. Rapid and drastic vegetation changes occurred at 5200 cal. yr BP, after the Mt Burney MB2 eruption, including the expansion and establishment of Pilgerodendron uviferum and the development of mixed Nothofagus-Pilgerodendron-Drimys woodland. Scattered populations of Nothofagus, as they occur today in westernmost Tierra del Fuego may be a good analogue for Nothofagus populations during the Lateglacial in eastern sites.

  • 14. Fontana, Sonia L.
    et al.
    Martha Bianchi, Maria
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Palaeoenvironmental changes since the Last Glacial Maximum: Patterns, timing and dynamics throughout South America2012In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 22, no 11, p. 1203-1206Article in journal (Other academic)
    Abstract [en]

    The vast diversity of present vegetation and environments that occur throughout South America (12 degrees N to 56 degrees S) is the result of diverse processes that have been operating and interacting at different spatial and temporal scales. Global factors, such as the concentration of CO2 in the atmosphere, may have been significant for high altitude vegetation during times of lower abundance, while lower sea levels of glacial stages potentially opened areas of continental shelf for colonisation during a substantial portion of the Quaternary. Latitudinal variation in orbital forcing has operated on a regional scale. The pace of climate change in the tropics is dominated by precessional oscillations of c. 20 kyr, while the high latitudes of the south are dominated by obliquity oscillations of c. 40 kyr. In particular, seasonal insolation changes forced by precessional oscillations must have had important consequences for the distribution limits of species, with potentially different effects depending on the latitude. The availability of taxa, altitude and human impact, among other events, have locally influenced the environments. Disentangling the different forcing factors of environmental change that operate on different timescales, and understanding the underlying mechanisms leads to considerable challenges for palaeoecologists. The papers in this Special Issue present a selection of palaeoecological studies throughout South America on vegetation changes and other aspects of the environment, providing a window on the possible complexity of the nature of transitions and timings that are potentially available.

  • 15.
    Giesecke, Thomas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    Bennett, Keith
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    The Holocene spread of Picea abies (L.) Karst. in Fennoscandia and adjacent areas2004In: Journal of Biogeography, Vol. 31, p. 1523-1548Article in journal (Refereed)
  • 16. Giesecke, Thomas
    et al.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Birks, H. John B.
    Bjune, Anne E.
    Bozilova, Elisaveta
    Feurdean, Angelica
    Finsinger, Walter
    Froyd, Cynthia
    Pokorny, Petr
    Roesch, Manfred
    Seppa, Heikki
    Tonkov, Spasimir
    Valsecchi, Verushka
    Wolters, Steffen
    The pace of Holocene vegetation change: testing for synchronous developments2011In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 30, no 19-20, p. 2805-2814Article, review/survey (Refereed)
    Abstract [en]

    Mid to high latitude forest ecosystems have undergone several major compositional changes during the Holocene. The temporal and spatial patterns of these vegetation changes hold potential information to their causes and triggers. Here we test the hypothesis that the timing of vegetation change was synchronous on a sub-continental scale, which implies a common trigger or a step-like change in climate parameters. Pollen diagrams from selected European regions were statistically divided into assemblage zones and the temporal pattern of the zone boundaries analysed. The results show that the temporal pattern of vegetation change was significantly different from random. Times of change cluster around 8.2, 4.8, 3.7, and 1.2 ka, while times of higher than average stability were found around 2.1 and 5.1 ka. Compositional changes linked to the expansion of Corylus avellana and Alnus glutinosa centre around 10.6 and 9.5 ka, respectively. A climatic trigger initiating these changes may have occurred 0.5 to 1 ka earlier, respectively. The synchronous expansion of C avellana and A. glutinosa exemplify that dispersal is not necessarily followed by population expansion. The partly synchronous, partly random expansion of A. glutinosa in adjacent European regions exemplifies that sudden synchronous population expansions are not species specific traits but vary regionally.

  • 17. Haberle, Simon
    et al.
    Bennett, Keith
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Postglacial formation and dynamics of North Patagonian Rainforest in the Chonos Archipelago, Southern Chile2004In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 23, no 23-24, p. 2433-2452Article in journal (Refereed)
    Abstract [en]

    Pollen analysis of continuous sediment cores from two lakes in the northern Chonos Archipelago (44°S) in southern Chile shows a complete postglacial record of vegetation change. The fossil records indicate that deglaciation was complete in the northern Chonos by at least 13,600 14C yr BP. Ericaceous heath and grassland persisted for more than 600 years after deglaciation under the influence of dry/cold climates and frequent burning. Nothofagus-Pilgerodendron-Podocarpus forest, with modern analogues in the southern Chonos Archipelago, was established across the northern islands by 12,400 14C yr BP under increasingly warm and wet climates. There is no evidence for a return to cooler climates during the Younger Dryas chronozone. The rise of Tepualia stipularis and Weinmannia trichosperma as important forest components between 10,600 and 6000 14C yr BP may be associated with climates that were warmer than present. The collapse of Pilgerodendron communities during this time may have been triggered by a combination of factors related to disturbance frequency including tephra deposition events, fire and climate change. After 6000 14C yr BP Pilgerodendron recovers and Nothofagus-Pilgerodendron-Tepualia forest persists until the present. European logging and burning activity may have increased the susceptibility of North Patagonian Rainforest to invasion by introduced species and to future collapse of the long-lived Pilgerodendron communities.

  • 18.
    Klimaschewski, A.
    et al.
    Queens Univ Belfast, Sch Geog Archaeol & Palaeoecol, Belfast BT7 1NN, Antrim, North Ireland..
    Barnekow, L.
    Lund Univ, Dept Geol, Quaternary Sci, SE-22362 Lund, Sweden..
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Queens Univ Belfast, Sch Geog Archaeol & Palaeoecol, Belfast BT7 1NN, Antrim, North Ireland..
    Andreev, A. A.
    Univ Cologne, Inst Geol & Mineral, D-50674 Cologne, Germany.;Kazan Fed Univ, Inst Geol & Petr Technol, Kazan 420008, Russia..
    Andren, E.
    Sodertorn Univ, Sch Nat Sci Technol & Environm Studies, SE-14189 Huddinge, Sweden..
    Bobrov, A. A.
    Moscow MV Lomonosov State Univ, Fac Soil Sci, Moscow 119899, Russia..
    Hammarlund, D.
    Lund Univ, Dept Geol, Quaternary Sci, SE-22362 Lund, Sweden..
    Holocene environmental changes in southern Kamchatka, Far Eastern Russia, inferred from a pollen and testate amoebae peat succession record2015In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 134, p. 142-154Article in journal (Refereed)
    Abstract [en]

    High resolution palaeoenvironmental records in Far-Eastern Russia are rare, and the Kamchatka Peninsula is among the least studied areas of the region. This paper describes a record spanning the last ca. 11,000 yr, obtained from a bog in the southern part of Kamchatka. The radiocarbon dated core was analysed for pollen, testate amoebae, charcoal and loss-on-ignition (LOI). The vegetation during the early Holocene was dominated by grasses (Poaceae), birch (Betula) and heath (Ericaceae p. p.). Around 10,300 cal yr BP there was a substantial change in the vegetation cover to shrub alder (Alnus viridis s.I.) stands with sedges and ferns (Polypodiophyta) as well as herbs such as meadow rue (Thalictrum) in the understory. In the surroundings of Utka peatlands started to form. The variations in the vegetation cover were most probably caused by climatic changes. At the beginning of sediment accumulation, before 10,300 cal yr BP, the composition of the vegetation points to cooler summers and/or decreased annual precipitation. Around 10,300 cal yr BP, changes in vegetation occurred due to rising temperatures and/or changed water regimes. Increased abundancies of dry indicating testate amoebae after 9100 cal yr BP point to intermediate to dry soil conditions. Between 8600 and 7700 cal yr BP tree alder (Alnus incana) was widely spread at the site which probably indicates optimal environmental conditions. The tephra layer at 381-384.5 cm (ca. 8500 cal yr BP) produces a strong impact on the testate amoebae assemblages. At 7700 cal yr BP there was a sudden drop of A. incana in the local vegetation. From this time on, A. incana and also A. viridis decrease continuously whereas Betula gradually increases. The upper part of the sequence (after 6300 cal yr BP) shows higher abundancies of meadowsweet (Filipendula) and sweet gale (Myrica) pollen. After 6300 cal yr BP, changes in testate amoebae demonstrate variable soil moisture conditions at the site. Between 3700 and 1800 cal yr BP, wet conditions dominate as dry indicating testate amoebae decrease. After 1800 cal yr BP soil conditions become more variable again but this time with dry dominating testate amoebae. In contrast to surrounding regions, there is no evidence of trees such as spruce or larch growing in the surroundings of the site even though those trees are characteristic of many eastern Siberian sites. This difference might be because of the maritime influence of the Okhotsk Sea. Even dwarf pine (Pinus pumila), which is currently widely dispersed in northern Kamchatka, became part of the local vegetation only during the last 700 yr.

  • 19. Mauquoy, Dmitri
    et al.
    Bennett, Keith
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Palaeobiology. Paleobiologi.
    Peatlands in Tierra del Fuego2006In: The biology of peatlands, Oxford University Press, Oxford , 2006Chapter in book (Other scientific)
  • 20.
    Parducci, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Edwards, Mary E.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Alm, Torbjörn
    Elverland, Ellen
    Tollefsrud, Mari Mette
    Jorgensen, Tina
    Houmark-Nielsen, Michael
    Larsen, Nicolaj Krog
    Kjaer, Kurt H.
    Fontana, Sonia L.
    Alsos, Inger Greve
    Willerslev, Eske
    Response to Comment on "Glacial Survival of Boreal Trees in Northern Scandinavia"2012In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 338, no 6108, p. 742-Article in journal (Other academic)
    Abstract [en]

    Birks et al. question our proposition that trees survived the Last Glacial Maximum (LGM) in Northern Scandinavia. We dispute their interpretation of our modern genetic data but agree that more work is required. Our field and laboratory procedures were robust; contamination is an unlikely explanation of our results. Their description of Endletvatn as ice-covered and inundated during the LGM is inconsistent with recent geological literature.

  • 21.
    Parducci, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Jorgensen, Tina
    Tollefsrud, Mari Mette
    Elverland, Ellen
    Alm, Torbjorn
    Fontana, Sonia L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Haile, James
    Matetovici, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Suyama, Yoshihisa
    Edwards, Mary E.
    Andersen, Kenneth
    Rasmussen, Morten
    Boessenkool, Sanne
    Coissac, Eric
    Brochmann, Christian
    Taberlet, Pierre
    Houmark-Nielsen, Michael
    Larsen, Nicolaj Krog
    Orlando, Ludovic
    Gilbert, M. Thomas P.
    Kjaer, Kurt H.
    Alsos, Inger Greve
    Willerslev, Eske
    Glacial Survival of Boreal Trees in Northern Scandinavia2012In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 335, no 6072, p. 1083-1086Article in journal (Refereed)
    Abstract [en]

    It is commonly believed that trees were absent in Scandinavia during the last glaciation and first recolonized the Scandinavian Peninsula with the retreat of its ice sheet some 9000 years ago. Here, we show the presence of a rare mitochondrial DNA haplotype of spruce that appears unique to Scandinavia and with its highest frequency to the west-an area believed to sustain ice-free refugia during most of the last ice age. We further show the survival of DNA from this haplotype in lake sediments and pollen of Trondelag in central Norway dating back similar to 10,300 years and chloroplast DNA of pine and spruce in lake sediments adjacent to the ice-free Andoya refugium in northwestern Norway as early as similar to 22,000 and 17,700 years ago, respectively. Our findings imply that conifer trees survived in ice-free refugia of Scandinavia during the last glaciation, challenging current views on survival and spread of trees as a response to climate changes.

  • 22.
    Parducci, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Matetovici, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Fontana, Sonia L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Suyama, Yoshihisa
    Haile, James
    Kjaer, Kurt H.
    Larsen, Nicolaj K.
    Drouzas, Andreas D.
    Willerslev, Eske
    Molecular- and pollen-based vegetation analysis in lake sediments from central Scandinavia2013In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 22, no 13, p. 3511-3524Article in journal (Refereed)
    Abstract [en]

    Plant and animal biodiversity can be studied by obtaining DNA directly from the environment. This new approach in combination with the use of generic barcoding primers (metabarcoding) has been suggested as complementary or alternative to traditional biodiversity monitoring in ancient soil sediments. However, the extent to which metabarcoding truly reflects plant composition remains unclear, as does its power to identify species with no pollen or macrofossil evidence. Here, we compared pollen-based and metabarcoding approaches to explore the Holocene plant composition around two lakes in central Scandinavia. At one site, we also compared barcoding results with those obtained in earlier studies with species-specific primers. The pollen analyses revealed a larger number of taxa (46), of which the majority (78%) was not identified by metabarcoding. The metabarcoding identified 14 taxa (MTUs), but allowed identification to a lower taxonomical level. The combined analyses identified 52 taxa. The barcoding primers may favour amplification of certain taxa, as they did not detect taxa previously identified with species-specific primers. Taphonomy and selectiveness of the primers are likely the major factors influencing these results. We conclude that metabarcoding from lake sediments provides a complementary, but not an alternative, tool to pollen analysis for investigating past flora. In the absence of other fossil evidence, metabarcoding gives a local and important signal from the vegetation, but the resulting assemblages show limited capacity to detect all taxa, regardless of their abundance around the lake. We suggest that metabarcoding is followed by pollen analysis and the use of species-specific primers to provide the most comprehensive signal from the environment.

  • 23. Willis, K. J.
    et al.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Burrough, S. L.
    Macias-Fauria, M.
    Tovar, C.
    Determining the response of African biota to climate change: using the past to model the future2013In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 368, no 1625, p. 20120491-Article, review/survey (Refereed)
    Abstract [en]

    Prediction of biotic responses to future climate change in tropical Africa tends to be based on two modelling approaches: bioclimatic species envelope models and dynamic vegetation models. Another complementary but underused approach is to examine biotic responses to similar climatic changes in the past as evidenced in fossil and historical records. This paper reviews these records and highlights the information that they provide in terms of understanding the local-and regional-scale responses of African vegetation to future climate change. A key point that emerges is that a move to warmer and wetter conditions in the past resulted in a large increase in biomass and a range distribution of woody plants up to 400-500 km north of its present location, the so-called greening of the Sahara. By contrast, a transition to warmer and drier conditions resulted in a reduction in woody vegetation in many regions and an increase in grass/savanna-dominated landscapes. The rapid rate of climate warming coming into the current interglacial resulted in a dramatic increase in community turnover, but there is little evidence for widespread extinctions. However, huge variation in biotic response in both space and time is apparent with, in some cases, totally different responses to the same climatic driver. This highlights the importance of local features such as soils, topography and also internal biotic factors in determining responses and resilience of the African biota to climate change, information that is difficult to obtain from modelling but is abundant in palaeoecological records.

  • 24. Willis, Katherine J.
    et al.
    Miguel B. Araújo, Miguel B.
    Bennett, Keith
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blanca Figueroa-Rangel, Blanca
    Froyd, Cynthia A.
    Myers, Norman
    How can a knowledge of the past help to conserve the future? Biodiversity conservation and the relevance of long-term ecological studies2007In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 362, no 1478, p. 175-186Article in journal (Refereed)
    Abstract [en]

    This paper evaluates how long-term records could and should be utilized in conservation policy and practice. Traditionally, there has been an extremely limited use of long-term ecological records (greater than 50 years) in biodiversity conservation. There are a number of reasons why such records tend to be discounted, including a perception of poor scale of resolution in both time and space, and the lack of accessibility of long temporal records to non-specialists. Probably more important, however, is the perception that even if suitable temporal records are available, their roles are purely descriptive, simply demonstrating what has occurred before in Earth's history, and are of little use in the actual practice of conservation. This paper asks why this is the case and whether there is a place for the temporal record in conservation management. Key conservation initiatives related to extinctions, identification of regions of greatest diversity/threat, climate change and biological invasions are addressed. Examples of how a temporal record can add information that is of direct practicable applicability to these issues are highlighted. These include (i) the identification of species at the end of their evolutionary lifespan and therefore most at risk from extinction, (ii) the setting of realistic goals and targets for conservation ‘hotspots’, and (iii) the identification of various management tools for the maintenance/restoration of a desired biological state. For climate change conservation strategies, the use of long-term ecological records in testing the predictive power of species envelope models is highlighted, along with the potential of fossil records to examine the impact of sea-level rise. It is also argued that a long-term perspective is essential for the management of biological invasions, not least in determining when an invasive is not an invasive. The paper concludes that often inclusion of a long-term ecological perspective can provide a more scientifically defensible basis for conservation decisions than the one based only on contemporary records. The pivotal issue of this paper is not whether long-term records are of interest to conservation biologists, but how they can actually be utilized in conservation practice and policy.

  • 25. Yeloff, D
    et al.
    Bennett, Keith D.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blaauw, Maarten
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Mauquoy, D
    Silassoo, Ü
    van der Plicht, J
    van Geel, B
    High precision C-14 dating of Holocene peat deposits: a comparison of Bayesian calibration and wiggle-matching approaches2006In: Quaternary Geochronology, ISSN 1871-1014, Vol. 1, no 3, p. 222-235Article in journal (Refereed)
    Abstract [en]

    The chronologies of five northern European ombrotrophic peat bogs subjected to a large ANIS C-14 dating effort (32-44 dates/site) are presented here. The results of Bayesian calibration (BCal) of dates with a prior assumption of chronological ordering were compared with a Bayesian wiggle-match approach (Bpeat) which assumes constant linear accumulation over sections of the peat profile. Interpolation of BCal age estimates of dense sequences of C-14 dates showed variable patterns of peat accumulation with time, with changes in accumulation occurring at intervals ranging from 20 to 50 cm. Within these intervals, peat accumulation appeared to be relatively linear. Close analysis suggests that some of the inferred variations in accumulation rate were related to the plant macrofossil composition of the peat. The wiggle-matched age-depth models had relatively high chronological uncertainty within intervals of closely spaced 14 C dates, suggesting that the premise of constant linear accumulation over large sections of the peat profile is unrealistic. Age models based on the assumption of linear accumulation over large parts of a peat core (and therefore only effective over millennial timescales), are not compatible with studies examining environmental change during the Holocene, where variability often occurs at decadal to centennial time-scales. Ideally, future wiggle-match age models should be constrained, with boundaries between sections based on the plant macrofossil composition of the peat and physical-chemical parameters such as the degree of decomposition. Strategies for the selection of material for dating should be designed so that there should be enough C-14 dates to accurately reconstruct the peat accumulation rate of each homogeneous stratigraphic unit.

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