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  • 1.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Cui, Qiao-Yu
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fyfe, Ralph
    University of Plymouth, UK.
    Lemdahl, Geoffrey
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, Florence
    University of Toulouse, France.
    Nielsen, Anne Birgitte
    Lund University.
    Poska, Anneli
    Lund University.
    Strandberg, Gustav
    Rossby Centre.
    Sugita, Shinya
    University of Tallinn, Estonia.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    From land cover-climate relationships at the subcontinental scale to land cover-environment relationships at the regional and local spatial scale – the contribution of pollen-based quantitative reconstructions of vegetation cover using the Landscape Reconstruction Algorithm approach2014In: Towards a more accurate quantification of human-environment interactions in the past: Open PAGES Focus 4 Workshop Human-Climate-Ecosystem Interactions University of Leuven, Belgium 3-7 February 2014, 2014, p. 25-26Conference paper (Refereed)
    Abstract [en]

    The Landscape Reconstruction Algorithm (Sugita 2007a,b) includes two models, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) that estimates vegetation abundance (% cover) within an area of ca. 100 km x 100 km, and LOVE (LOcal Vegetation Estimates) that estimates vegetation abundance at the local spatial scale, i.e. within the Relevant Source Area of Pollen (RSAP sensu Sugita, 2004) that is the smallest area around the study site for which the reconstruction is valid. The RSAP is estimated by the LOVE model and varies between sites and vegetation settings; so far, it was estimated to vary between < 1 - < 10 km in most ecological settings of the Holocene in NW Europe. We used the REVEALS model and over 600 pollen records from pollen data bases and individual researchers to reconstruct land-cover in NW Europe N of the Alps for key time windows of the Holocene in order to assess model-based reconstructions of anthropogenic land-cover change (ALCC) (e.g. Kaplan et al., 2009) and model (LPJ-GUESS) simulations of past potential (climate-induced vegetation), and to study past land cover – climate interactions using a regional climate model (RCA3). We used the REVEALS model and the complete LRA approach (REVEALS + LOVE models) along with two pollen records from large lakes and three pollen records from small bogs to reconstruct the local-scale land-cover in central Småland, southern Sweden, to study the relationship between vegetation composition, fire, climate and human impact at the regional and local spatial scales with the objective to discuss biodiversity issues. Our results suggest that i) past subcontinental to regional ALCC did influence regional climate through biogeophysical processes at the landatmosphere interface (Strandberg et al., submitted), and ii) local land-cover change, both natural and anthropogenic, govern environmental changes such as fire and biodiversity (Cui et al., 2013; Cui et al., submitted).

  • 2. Gaillard, Marie-José
    et al.
    Cui, Qiao-Yu
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Chinese Academy of Sciences, China.
    Lemdahl, Geoffrey
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    The potential of pollen-based quantitative vegetation reconstructions in studies of past human settlements and use of resources – examples from Europe2015In: Geophysical Research Abstracts, 2015, Vol. 17Conference paper (Refereed)
    Abstract [en]

    There is a long tradition of collaboration between palaeoecologists and archaeologists in many parts of the world with the purpose of reconstructing the environment of humans through time and the study of the interactions between humans and their environment. Vegetation (i.e. vegetated landscapes and plants) has long been one of the most important parts of the environment for humans’ resources. Thanks to the interpretation of palaeoecological data such as pollen and plant macrofossils, it is well known that humans have used plants for their subsistence and formed many landscapes of the Earth through their activities over many millennia. Pollen analysis in particular has been used to reconstruct the landscapes of humans in order i) to learn something on their use of the landscape for building material, grazing and food (e.g. woods, grazed land, cultivated fields), and ii) to understand their influence on the landscape through deforestation in particular. Pollen data as proxy records of vegetation have been very useful to provide qualitative descriptions of cultural landscapes through time in terms of the presence of major tree, shrub and herb species, and the character of the landscape, wooded, “half-wooded” (or partly wooded), and primarily open (poorly wooded) (1). Efforts to calibrate pollen onto land-use in the 1990ies has made possible to provide more precise and detailed interpretation of pollen records in terms of land-use type (2). However, when it came to questions related to the size of cultivated land or grazed land in relation to wooded land, interpretation of pollen records has been problematic until recently. The non-linear relationship between pollen and vegetation due to inter-taxonomic differences in pollen productivity and pollen dispersion and deposition characteristics of plant taxa has long hampered estimation of the percentage cover of plant taxa or landscape units in the past. Thanks torecent developments in pollen-vegetation modelling, a new approach - the Landscape Reconstruction Algorithm (LRA) (3, 4) - makes it possible to estimate the cover of plant taxa or landscape units at both regional and local spatial scales using pollen records. The LRA has been tested and applied in various types of studies in Europe in particular. Examples from Europe and Scandinavia show that pollen-based quantitative reconstructions of vegetation cover, in combination with other palaeoecological records such as insect and plant macroremains, show the great potential of such studies to provide new insights on the use of landscapes and vegetation by humans in the past and its environmental consequences at both regional and local spatial scales (5, 6). These results provide a new environmental framework for the discussion and testing of hypotheses based on archaeological data.

  • 3.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Kaplan, Jed O
    University of Lausanne, Switzerland.
    Kleinen, Thomas
    Max Planck Institut für Meteorologie, Germany.
    Nielsen, Anne Brigitte
    Lund University.
    Poska, Anneli
    Lund University.
    Samuelsson, Patrick
    Rossby Centre.
    Strandberg, Gustav
    Rossby Centre.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Has anthropogenic land-cover change been a significant climate forcing in the past?: An assessment for the Baltic Sea catchment area based on a literature review2015In: Geophysical Research Abstracts, 2015, Vol. 17Conference paper (Refereed)
    Abstract [en]

    We reviewed the recent published scientific literature on land cover-climate interactions at the global and regional spatial scales with the aim to assess whether it is convincingly demonstrated that anthropogenic land-cover change (ALCC) has been (over the last centuries and millennia) a significant climate forcing at the global scale, and more specifically at the scale of the Baltic Sea catchment area. The conclusions from this review are as follows: i) anthropogenic land-cover change (ALCC) is one of the few climate forcings for which the net direction of the climate response in the past is still not known. The uncertainty is due to the often counteracting temperature responses to the many biogeophysical effects, and to the biogeochemical vs biogeophysical effects; ii) there is no indication that deforestation in the Baltic Sea area since AD 1850 would have been a major cause of the recent climate warming in the region through a positive biogeochemical feedback; iii) several model studies suggest that boreal reforestation might not be an effective climate warming mitigation tool as it might lead to increased warming through biogeophysical processes; iv) palaeoecological studies indicate a major transformation of the landscape by anthropogenic activities in the southern zone of the study region occurring between 6000 and 3000/2500 calendar years before present (cal. BP) (1) ; v) the only modelling study so far of the biogeophysical effects of past ALCCs on regional climate in Europe suggests that a deforestation of the magnitude of that reconstructed for the past (between 6000 and 200 cal BP) can produce changes in winter and summer temperatures of +/- 1, the sign of the change depending on the season and the region (2). Thus, if ALCC and their biogeophysical effects did matter in the past, they should matter today and in the future. A still prevailing idea is that planting trees will mitigate climate warming through biogeochemical effects. Therefore, there is still an urgent need to better understand the biogeophysical effects on regional and continental climate of afforestation in the hemiboreal and boreal regions, and their significance in relation to the biogeochemical effects.

  • 4.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Kleinen, Thomas
    Max Planck Institute for Meteorology, Germany.
    Samuelsson, Patrick
    Swedish Meteorological and Hydrological Institute.
    Nielsen, Anne Birgitte
    Lund University.
    Bergh, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Kaplan, Jed
    University of Lausanne, Switzerland.
    Poska, Anneli
    Lund University.
    Sandström, Camilla
    Swedish University of Agricultural Sciences.
    Strandberg, Gustav
    Swedish Meteorological and Hydrological Institute.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Wramneby, Anna
    Lund University.
    Causes of Regional Change: Land Cover2015In: Second Assessment of Climate Change for the Baltic Sea Basin / [ed] The BACC II Author team, Springer, 2015, p. 453-477Chapter in book (Refereed)
    Abstract [en]

    Anthropogenic land-cover change (ALCC) is one of the few climate forcings for which the net direction of the climate response over the last two centuries is still not known. The uncertainty is due to the often counteracting temperature responses to the many biogeophysical effects and to the biogeochemical versus biogeophysical effects. Palaeoecological studies show that the major transformation of the landscape by anthropogenic activities in the southern zone of the Baltic Sea basin occurred between 6000 and 3000/2500 cal year BP. The only modelling study of the biogeophysical effects of past ALCCs on regional climate in north-western Europe suggests that deforestation between 6000 and 200 cal year BP may have caused significant change in winter and summer temperature. There is no indication that deforestation in the Baltic Sea area since AD 1850 would have been a major cause of the recent climate warming in the region through a positive biogeochemical feedback. Several model studies suggest that boreal reforestation might not be an effective climate warming mitigation tool as it might lead to increased warming through biogeophysical processes.

  • 5.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Strandberg, G.
    Poska, A.
    Kaplan, J.O.
    Smith, B.
    Sugita, S.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, F.
    Fyfe, R.
    Nielsen, A.B.
    Marquer, L.
    The role of holocene land-use change (6K to 0.2K before present) on regional climate via biogeophysical feedbacks in NW Europe2014In: 4th iLEAPS science conference Terrestrial ecosystem, atmosphere and people in the Earth System 12-14 May 2014, Nanjing, China, 2014Conference paper (Refereed)
  • 6.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Strandberg, Gustav
    Poska, Anneli
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, Florence
    Kaplan, Jed O.
    Land cover-climate interactions in the past for the understanding of current and future climate change: the LANDCLIM project2014In: Proceedings of the Global Land Project 2nd Open Science Meeting, Berlin, March 19th – 21st, 2014: Land transformations : between global challenges and local realities, Amsterdam/Berlin/Sao Paulo: Global Land Project , 2014, p. 229-230Conference paper (Other academic)
    Abstract [en]

    The LANDCLIM (LAND cover – CLIMate interactions in NW Europe during the Holocene) project has the overall aim to quantify human-induced changes in regional vegetation/land-cover in northwestern and western Europe North of the Alps during the Holocene (the last 11 500 years) with the purpose to evaluate and further refine the dynamic vegetation model LPJGUESS and the regional climate model RCA3, and to assess the possible effects on the climate development of two historical processes, i.e. climate-driven changes in vegetation and human-induced changes in land cover, via the influence of forested versus non-forested land cover on shortwave albedo, energy and water fluxes. Accounting for land surface changes may be particularly important for regional climate modeling, as the biophysical feedbacks operate at this scale. The aims of the LANDCLIM project are achieved by applying a model-data comparison scheme. The REVEALS model is used to estimate land cover from pollen data for 10 plant functional types (PFTs) and 5 time windows of the Holocene - modern time, 200 BP, 500 BP, 3000 BP and 6000 BP. The REVEALS estimates are then compared to the LPJGUESS simulations of potential vegetation and with the ALCC scenarios of Kaplan et al. (KK10) and Klein-Goldewijk et al. (HYDE). The alternative descriptions of past land-cover are then used in the regional climate model RCA3 to study the effect of anthropogenic land-cover on climate. The model-simulated climate is finally compared to palaeoclimate proxies other than pollen. The REVEALS estimates demonstrate that the study region was characterized by larger areas of human-induced openland than pollen percentages suggest, and that these areas were already very large by 3000 BP. The KK10 scenarios were found to be closer to the REVEALS estimates than the HYDE scenarios. LPJGUESS simulates potential climate-induced vegetation. The results from the RCA3 runs at 200 BP and 6000 BP using the LPJGUESS and KK10 land-cover descriptions indicate that past human-induced deforestation did produce a decrease in summer temperatures of >0 - 1.5°C due to biogeophysical processes, and that the degree of decrease differed between regions; the effect of human-induced deforestation on winter temperatures was shown to be more complex. The positive property of forests as CO2 sinks is well known. But afforestation (i.e. planting forest) may also have the opposite effect of warming the climate through biogeophysical processes. Careful studies on land cover-climate interactions are essential to understand the net result of all possible processes related to anthropogenic land-cover change so that relevant landscape management can be implemented for mitigation of climate warming.

  • 7.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Sugita, Shinya
    Tallinn University, Estonia.
    Mazier, Florence
    University of Toulouse, France ; Lund University.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Broström, A
    Lund University.
    Hickler, T
    Lund University.
    Kaplan, J.O.
    Ecole Polytechnique Fédérale de Lausanne, Switzerland.
    Kjellström, E
    Swedish Meteorological and Hydrological Institute.
    Kokfelt, U
    Lund University.
    Kunes, P
    Aarhus University, Denmark.
    Lemmen, C
    Miller, P
    Olofsson, J
    Poska, A
    Rundgren, M
    Smith, B
    Strandberg, G
    Fyfe, R
    Nielsen, A.B.
    Alenius, T
    Balakauskas, L
    Barnekov, L
    Birks, H.J.B.
    Bjune, A
    Bjorkman, L
    Giesecke, T
    Hjelle, K
    Kalnina, L
    Kangur, M
    van der Knaap, W.O.
    Koff, T
    Lageras, P
    Latalowa, M
    Leydet, M
    Lechterbeck, J
    Lindbladh, M
    Odgaard, B
    Peglar, S
    Segerstrom, U
    von Stedingk, H
    Seppa, H
    Holocene land-cover reconstructions for studies on land cover-climate feedbacks2010In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 6, p. 483-499Article in journal (Refereed)
    Abstract [en]

    The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover – CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene, and (4) to discuss the implications and future directions in climate and vegetation/land-cover modeling, and in the assessment of the effects of human-induced changes in land-cover on the regional climate through altered feedbacks. The existing ALCC scenarios show large discrepancies between them, and few cover time periods older than AD 800. When these scenarios are used to assess the impact of human land-use on climate, contrasting results are obtained. It emphasizes the need for methods such as the REVEALS model-based land-cover reconstructions. They might help to fine-tune descriptions of past land-cover and lead to a better understanding of how long-term changes in ALCC might have influenced climate. The REVEALS model is demonstrated to provide better estimates of the regional vegetation/landcover changes than the traditional use of pollen percentages. This will achieve a robust assessment of land cover at regional- to continental-spatial scale throughout the Holocene. We present maps of REVEALS estimates for the percentage cover of 10 plant functional types (PFTs) at 200 BP and 6000 BP, and of the two open-land PFTs “grassland” and “agricultural land” at five time-windows from 6000 BP to recent time. The LANDCLIM results are expected to provide crucial data to reassess ALCC estimates for a better understanding of the land suface-atmosphere interactions.

  • 8.
    Gaillard, Marie-José
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Sugita, Shinya
    Rundgren, Mats
    Smith, Benjamin
    Mazier, Florence
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Fyfe, Ralph
    Kokfelt, Ulla
    Nielsen, Anne-Birgitte
    Strandberg, Gustav
    Team, LANDCLIM members
    Pollen-inferred quantitative reconstructions of Holocene land-cover in NW Europe for the evaluation of past climate-vegetation feedbacks: The Swedish LANDCLIM project and the NordForsk LANDCLIM network2010Conference paper (Refereed)
  • 9.
    Kaplan, Jed O.
    et al.
    Max Planck Inst Sci Human Hist, Germany;ARVE Res Sarl, Switzerland.
    Krumhardt, Kristen M.
    Univ Colorado Boulder, USA.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sugita, Shinya
    Tallinn Univ, Estonia.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fyfe, Ralph
    Univ Plymouth, UK.
    Marquer, Laurent
    Univ Toulouse Jean Jaures, France.
    Mazier, Florence
    Univ Toulouse Jean Jaures, France.
    Nielsen, Anne Birgitte
    Lund University.
    Constraining the Deforestation History of Europe: Evaluation of Historical Land Use Scenarios with Pollen-Based Land Cover Reconstructions2017In: Land, ISSN 2073-445X, E-ISSN 2073-445X, Vol. 6, no 4, article id 91Article in journal (Refereed)
    Abstract [en]

    Anthropogenic land cover change (ALCC) is the most important transformation of the Earth system that occurred in the preindustrial Holocene, with implications for carbon, water and sediment cycles, biodiversity and the provision of ecosystem services and regional and global climate. For example, anthropogenic deforestation in preindustrial Eurasia may have led to feedbacks to the climate system: both biogeophysical, regionally amplifying winter cold and summer warm temperatures, and biogeochemical, stabilizing atmospheric CO2 concentrations and thus influencing global climate. Quantification of these effects is difficult, however, because scenarios of anthropogenic land cover change over the Holocene vary widely, with increasing disagreement back in time. Because land cover change had such widespread ramifications for the Earth system, it is essential to assess current ALCC scenarios in light of observations and provide guidance on which models are most realistic. Here, we perform a systematic evaluation of two widely-used ALCC scenarios (KK10 and HYDE3.1) in northern and part of central Europe using an independent, pollen-based reconstruction of Holocene land cover (REVEALS). Considering that ALCC in Europe primarily resulted in deforestation, we comparemodeled land use with the cover of non-forest vegetation inferred from the pollen data. Though neither land cover change scenario matches the pollen-based reconstructions precisely, KK10 correlates well with REVEALS at the country scale, while HYDE systematically underestimates land use with increasing magnitude with time in the past. Discrepancies between modeled and reconstructed land use are caused by a number of factors, including assumptions of per-capita land use and socio-cultural factors that cannot be predicted on the basis of the characteristics of the physical environment, including dietary preferences, long-distance trade, the location of urban areas and social organization.

  • 10.
    Kuosmanen, Niina
    et al.
    Czech Univ Life Sci Prague, Czech Republic;Univ Helsinki, Finland.
    Marquer, Laurent
    Lund University;Univ Toulouse Jean Jaures, France.
    Tallavaara, Miikka
    Univ Helsinki, Finland.
    Molinari, Chiara
    Lund University.
    Zhang, Yurui
    Univ Helsinki, Finland;Vrije Univ Amsterdam, Netherlands.
    Alenius, Teija
    Univ Helsinki, Finland.
    Edinborough, Kevan
    UCL, UK.
    Pesonen, Petro
    Natl Board Antiqu, Finland.
    Reitalu, Triin
    Tallinn Univ Technol, Estonia.
    Renssen, Hans
    Vrije Univ Amsterdam, Netherlands;Univ Coll Southeast Norway, Norway.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Seppa, Heikki
    Univ Helsinki, Finland.
    The role of climate, forest fires and human population size in Holocene vegetation dynamics in Fennoscandia2018In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 29, no 3, p. 382-392Article in journal (Refereed)
    Abstract [en]

    QuestionsWe investigated the changing role of climate, forest fires and human population size in the broad-scale compositional changes in Holocene vegetation dynamics before and after the onset of farming in Sweden (at 6,000cal yr BP) and in Finland (at 4,000calyr BP). LocationSouthern and central Sweden, SW and SE Finland. MethodsHolocene regional plant abundances were reconstructed using the REVEALS model on selected fossil pollen records from lakes. The relative importance of climate, fires and human population size on changes in vegetation composition was assessed using variation partitioning. Past climate variable was derived from the LOVECLIM climate model. Fire variable was reconstructed from sedimentary charcoal records. Estimated trend in human population size was based on the temporal distribution of archaeological radiocarbon dates. ResultsClimate explains the highest proportion of variation in vegetation composition during the whole study period in Sweden (10,000-4,000cal yr BP) and in Finland (10,000-1,000cal yr BP), and during the pre-agricultural period. In general, fires explain a relatively low proportion of variation. Human population size has significant effect on vegetation dynamics after the onset of farming and explains the highest variation in vegetation in S Sweden and SW Finland. ConclusionsMesolithic hunter-gatherer populations did not significantly affect vegetation composition in Fennoscandia, and climate was the main driver of changes at that time. Agricultural communities, however, had greater effect on vegetation dynamics, and the role of human population size became a more important factor during the late Holocene. Our results demonstrate that climate can be considered the main driver of long-term vegetation dynamics in Fennoscandia. However, in some regions the influence of human population size on Holocene vegetation changes exceeded that of climate and has a longevity dating to the early Neolithic.

  • 11.
    Marquer, Laurent
    et al.
    Lund University, Sweden;Univ Toulouse Jean Jaures, France.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sugita, Shinya
    Tallinn Univ, Estonia.
    Poska, Anneli
    Lund University, Sweden;Tallinn Univ Technol, Estonia.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, Florence
    Univ Toulouse Jean Jaures, France.
    Nielsen, Anne Birgitte
    Lund University, Sweden.
    Fyfe, Ralph M.
    Univ Plymouth, UK.
    Jonsson, Anna Maria
    Lund University, Sweden.
    Smith, Benjamin
    Lund University, Sweden.
    Kaplan, Jed O.
    Ecole Polytech Fed Lausanne, Switzerland.
    Alenius, Teija
    Univ Helsinki, Finland;Univ Turku, Finland.
    Birks, H. John B.
    Univ Bergen, Norway;UCL, UK.
    Bjune, Anne E.
    Univ Bergen, Norway;Uni Res Climate, Norway.
    Christiansen, Jorg
    Univ Göttingen, Germany.
    Dodson, John
    Univ Wollongong, Australia;Chinese Acad Sci, Peoples Republic of China.
    Edwards, Kevin J.
    Univ Aberdeen, UK;Univ Cambridge, UK.
    Giesecke, Thomas
    Univ Göttingen, Germany.
    Herzschuh, Ulrike
    Univ Potsdam, Germany.
    Kangur, Mihkel
    Tallinn Univ, Estonia.
    Koff, Tiiu
    Tallinn Univ, Estonia.
    Latalowa, Maligorzata
    Univ Gdansk, Poland.
    Lechterbeck, Jutta
    Univ Stavanger, Norway.
    Olofsson, Jorgen
    Lund University, Sweden.
    Seppa, Heikki
    Univ Helsinki, Finland.
    Quantifying the effects of land use and climate on Holocene vegetation in Europe2017In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 171, p. 20-37Article in journal (Refereed)
    Abstract [en]

    Early agriculture can be detected in palaeovegetation records, but quantification of the relative importance of climate and land use in influencing regional vegetation composition since the onset of agriculture is a topic that is rarely addressed. We present a novel approach that combines pollen-based REVEALS estimates of plant cover with climate, anthropogenic land-cover and dynamic vegetation modelling results. This is used to quantify the relative impacts of land use and climate on Holocene vegetation at a sub-continental scale, i.e. northern and western Europe north of the Alps. We use redundancy analysis and variation partitioning to quantify the percentage of variation in vegetation composition explained by the climate and land-use variables, and Monte Carlo permutation tests to assess the statistical significance of each variable. We further use a similarity index to combine pollen based REVEALS estimates with climate-driven dynamic vegetation modelling results. The overall results indicate that climate is the major driver of vegetation when the Holocene is considered as a whole and at the sub-continental scale, although land use is important regionally. Four critical phases of land-use effects on vegetation are identified. The first phase (from 7000 to 6500 BP) corresponds to the early impacts on vegetation of farming and Neolithic forest clearance and to the dominance of climate as a driver of vegetation change. During the second phase (from 4500 to 4000 BP), land use becomes a major control of vegetation. Climate is still the principal driver, although its influence decreases gradually. The third phase (from 2000 to 1500 BP) is characterised by the continued role of climate on vegetation as a consequence of late-Holocene climate shifts and specific climate events that influence vegetation as well as land use. The last phase (from 500 to 350 BP) shows an acceleration of vegetation changes, in particular during the last century, caused by new farming practices and forestry in response to population growth and industrialization. This is a unique signature of anthropogenic impact within the Holocene but European vegetation remains climatically sensitive and thus may continue to respond to ongoing climate change. (C) 2017 Elsevier Ltd. All rights reserved.

  • 12.
    Marquer, Laurent
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sugita, Shinya
    Tallinn Univ, Estonia.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, Florence
    Univ Toulouse, France.
    Nielsen, Anne Birgitte
    Lund University.
    Fyfe, Ralph
    Univ Plymouth, UK.
    Vad Odgaard, B.
    Aarhus University, Denmark.
    Alenius, T.
    University of Helsinki, Finland;University of Turku, Finland.
    Birks, H.J.B.
    University of Bergen, Norway;University College London, UK;University of Oxford, UK.
    Bjune, A.E.
    University of Bergen, Norway.
    Christiansen, J.
    University of Göttingen, Germany.
    Dodson, J.
    Australian Nuclear Science and Technology Organisation, Australia.
    Edwards, K.J.
    University of Aberdeen, UK.
    Giesecke, T.
    University of Göttingen, Germany.
    Herzschuh, U.
    Universität Potsdam, Germany.
    Kangur, M.
    Tallinn University, Estonia.
    Lorenz, S.
    Ernst-Moritz-Arndt-University, Germany.
    Poska, Anneli
    Lund University.
    Schult, M.
    Ernst-Moritz-Arndt-University, Germany.
    Seppä, H.
    University of Helsinki, Finland.
    Holocene changes in vegetation composition in northern Europe: why quantitative pollen-based vegetation reconstructions matter2014In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, no 90, p. 199-216Article in journal (Refereed)
    Abstract [en]

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

  • 13. Mazier, F.
    et al.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Kunes, P.
    Sugita, S.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Brostrom, A.
    Testing the effect of site selection and parameter setting on REVEALS-model estimates of plant abundance using the Czech Quaternary Palynological Database2012In: Review of Palaeobotany and Palynology, ISSN 0034-6667, E-ISSN 1879-0615, Vol. 187, p. 38-49Article in journal (Refereed)
    Abstract [en]

    REVEALS-based quantitative reconstruction of Holocene vegetation cover (expressed in plant functional types. PFTs) is used in the LANDCLIM project to assess the effect of human-induced land-cover change on past climate in NW Europe. Using the Czech Quaternary Pollen Database, this case study evaluates the extent to which selection of data and input parameters for the REVEALS model applications would affect reconstruction outcomes. The REVEALS estimates of PFTs (grid-cell based REVEALS PET estimates, GB REVEALS PFT-s) are calculated for five time windows of the Holocene using fossil pollen records available in each 1 degrees x1 degrees grid cell of the Czech Republic. The input data and parameters selected for testing are: basin type and size, number of C-14 dates used to establish the chronology of the pollen records, number of taxa, and pollen productivity estimates (PPE). We used the Spearman correlation coefficient to test the hypothesis that there is no association between GB REVEALS PET-s using different data and parameter inputs. The results show that differences in the basin size and type, number of dates, number and type of taxa (entomophilous included or not), and PPE dataset do not affect the rank orders of the GB REVEALS PET-s significantly, except for the cases when entomophilous taxa are included. It implies that, given careful selection of data and parameter and interpretation of results, REVEALS applications can use pollen records from lakes and bogs of different sizes together for reconstruction of past land cover at the regional to sub-continental spatial scales for purposes such as the study of past land cover-climate interactions. Our study also provides useful criteria to set up protocols for data compilation REVEALS applications of this kind. (C) 2012 Elsevier B.V. All rights reserved.

  • 14. Mazier, Florence
    et al.
    Kunes, Petr
    Sugita, Shinya
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Broström, Anna
    Gaillard, Marie-José
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Pollen-inferred quantitative reconstructions of Holocene land-cover in NW Europe for the evaluation of past climate-vegetation feedbacks III: Evaluation of the REVEALS-based reconstructions using the Czech Republic pollen database2010Conference paper (Refereed)
  • 15.
    Pirzamanbein, Behnaz
    et al.
    Lund University.
    Lindstrom, Johan
    Lund University.
    Poska, Anneli
    Lund University;Tallinn Univ Technol, Estonia.
    Sugita, Shinya
    Tallinn Univ Technol, Estonia.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fyfe, Ralph
    Univ Plymouth, UK.
    Mazier, Florence
    Univ Toulouse, France.
    Nielsen, Anne B.
    Lund University.
    Kaplan, Jed O.
    Univ Geneva, Switzerland.
    Bjune, Anne E.
    Uni Res & Bjerknes Ctr Climate Res, Norway.
    Birks, H. John B.
    University of Bergen, Norway;University College London, UK;University of Oxford, UK.
    Giesecke, Thomas
    University of Göttingen, Germany.
    Kangur, Mikhel
    Tallinn University, Estonia.
    Latalowa, Malgorzata
    University of Gdańsk, Poland.
    Marquer, Laurent
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Smith, Benjamin
    Lund University.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Creating spatially continuous maps of past land cover from point estimates: A new statistical approach applied to pollen data2014In: Ecological Complexity: An International Journal on Biocomplexity in the Environment and Theoretical Ecology, ISSN 1476-945X, E-ISSN 1476-9840, Vol. 20, p. 127-141Article in journal (Refereed)
    Abstract [en]

    Reliable estimates of past land cover are critical for assessing potential effects of anthropogenic land-cover changes on past earth surface-climate feedbacks and landscape complexity. Fossil pollen records from lakes and bogs have provided important information on past natural and human-induced vegetation cover. However, those records provide only point estimates of past land cover, and not the spatially continuous maps at regional and sub-continental scales needed for climate modelling. We propose a set of statistical models that create spatially continuous maps of past land cover by combining two data sets: 1) pollen-based point estimates of past land cover (from the REVEALS model) and 2) spatially continuous estimates of past land cover, obtained by combining simulated potential vegetation (from LPJ-GUESS) with an anthropogenic land-cover change scenario (KK10). The proposed models rely on statistical methodology for compositional data and use Gaussian Markov Random Fields to model spatial dependencies in the data. Land-cover reconstructions are presented for three time windows in Europe: 0.05, 0.2, and 6 ka years before present (BP). The models are evaluated through cross-validation, deviance information criteria and by comparing the reconstruction of the 0.05 ka time window to the present-day land-cover data compiled by the European Forest Institute (EFI). For 0.05 ka, the proposed models provide reconstructions that are closer to the EFI data than either the REVEALS- or LPJ-GUESS/KK10-based estimates; thus the statistical combination of the two estimates improves the reconstruction. The reconstruction by the proposed models for 0.2 ka is also good. For 6 ka, however, the large differences between the REVEALS- and LPJ-GUESS/KK10-based estimates reduce the reliability of the proposed models. Possible reasons for the increased differences between REVEALS and LPJ-GUESS/KK10 for older time periods and further improvement of the proposed models are discussed. (C) 2014 Elsevier B.V. All rights reserved.

  • 16.
    Roberts, N.
    et al.
    Plymouth Univ, UK.
    Fyfe, R. M.
    Plymouth Univ, UK.
    Woodbridge, J.
    Plymouth Univ, UK.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Davis, B. A. S.
    Univ Lausanne, Switzerland.
    Kaplan, J. O.
    Max Planck Inst Sci Human Hist, Germany;ARVE Res SARL, Switzerland.
    Marquer, L.
    Lund University.
    Mazier, F.
    Jean Jaures Univ, France.
    Nielsen, A. B.
    Lund University.
    Sugita, S.
    Tallinn Univ, Estonia.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Leydet, M.
    Aix Marseille Univ, France.
    Europe's lost forests: a pollen-based synthesis for the last 11,000 years2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 716Article in journal (Refereed)
    Abstract [en]

    8000 years ago, prior to Neolithic agriculture, Europe was mostly a wooded continent. Since then, its forest cover has been progressively fragmented, so that today it covers less than half of Europe's land area, in many cases having been cleared to make way for fields and pasture-land. Establishing the origin of Europe's current, more open land-cover mosaic requires a long-term perspective, for which pollen analysis offers a key tool. In this study we utilise and compare three numerical approaches to transforming pollen data into past forest cover, drawing on >1000 C-14-dated site records. All reconstructions highlight the different histories of the mixed temperate and the northern boreal forests, with the former declining progressively since similar to 6000 years ago, linked to forest clearance for agriculture in later prehistory (especially in northwest Europe) and early historic times (e.g. in north central Europe). In contrast, extensive human impact on the needle-leaf forests of northern Europe only becomes detectable in the last two millennia and has left a larger area of forest in place. Forest loss has been a dominant feature of Europe's landscape ecology in the second half of the current interglacial, with consequences for carbon cycling, ecosystem functioning and biodiversity.

  • 17. Strandberg, G.
    et al.
    Kjellström, E.
    Poska, A.
    Wagner, S.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mauri, A.
    Birks, H.J.B.
    Bjune, A.E.
    Davis, B. A. S.
    Fyfe, R.
    Giesecke, T.
    Kalnina, L.
    Kangur, M.
    Kaplan, J.O.
    van der Knaap, W.O.
    Kokfelt, U.
    Kuneš, P.
    Latałowa, M.
    Marquer, Laurent
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, F.
    Nielsen, A.B.
    Smith, B.
    Seppä, H.
    Sugita, S.
    Regional climate model simulations for Europe at 6 k and 0.2 k yr BP: sensitivity to changes in anthropogenic deforestation.2013In: Climate of the Past Discussions, ISSN 1814-9340, E-ISSN 1814-9359, Vol. 9, no 5, p. 5785-5836Article in journal (Refereed)
    Abstract [en]

    This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, ~6 k BP and ~0.2 k BP in Europe. We apply RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthropogenic land cover (deforestation) as simulated by the HYDE model (V + H), and (iii) potential vegetation with anthropogenic land cover as simulated by the KK model (V + K). The KK model estimates are closer to a set of pollen-based reconstructions of vegetation cover than the HYDE model estimates. The climate-model results show that the simulated effects of deforestation depend on both local/regional climate and vegetation characteristics. At ~6 k BP the extent of simulated deforestation in Europe is generally small, but there are areas where deforestation is large enough to produce significant differences in summer temperatures of 0.5–1 °C. At ~0.2 k BP, simulated deforestation is much more extensive than previously assumed, in particular according to the KK model. This leads to significant temperature differences in large parts of Europe in both winter and summer. In winter, deforestation leads to lower temperatures because of the differences in albedo between forested and unforested areas, particularly in the snow-covered regions. In summer, deforestation leads to higher temperatures in central and eastern Europe since evapotranspiration from unforested areas is lower than from forests. Summer evaporation is already limited in the southernmost parts of Europe under potential vegetation conditions and, therefore, cannot become much lower. Accordingly, the albedo effect dominates also in summer, which implies that deforestation causes a decrease in temperatures. Differences in summer temperature due to deforestation range from −1 °C in south-western Europe to +1 °C in eastern Europe. The choice of anthropogenic land cover estimate has a significant influence on the simulated climate, but uncertainties in palaeoclimate proxy data for the two time periods do not allow for a thorough comparison with climate model results.

  • 18.
    Strandberg, G.
    et al.
    Swedish Meteorological and Hydrological Institute;Stockholm University.
    Kjellström, E.
    Swedish Meteorological and Hydrological Institute;Stockholm University.
    Poska, Anneli
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University.
    Wagner, S.
    Helmholtz-Zentrum Geesthacht, Germany.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mauri, A.
    University of Geneva, Switzerland.
    Davis, B.A.S.
    University of Geneva, Switzerland.
    Kaplan, J.O.
    University of Geneva, Switzerland.
    Birks, H. J. B.
    University of Bergen, Norway;University College London, UK;University of Oxford, UK.
    Bjune, A.E.
    Bjerknes Centre for Climate Research, Norway.
    Fyfe, R.
    University of Plymouth, UK.
    Giesecke, T.
    University of Göttingen, Germany.
    Kalnina, L.
    University of Latvia, Latvia.
    Kangur, M.
    Tallin University, Estonia.
    van der Knaap, W.O.
    University of Bern, Switzerland.
    Kokfelt, U.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University;University of Copenhagen, Denmark.
    Kuneš, P.
    Charles University in Prague, Czech Republic.
    Latałowa, M.
    University of Gdańsk, Poland.
    Marquer, Laurent
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, F.
    Lund University;University of Toulouse, France.
    Nielsen, Anne Birgitte
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University.
    Smith, B.
    Lund University.
    Seppä, H.
    University of Helsinki, Finland.
    Sugita, S.
    Tallin University, Estonia.
    Regional climate model simulations for Europe at 6 and 0.2 k BP: sensitivity to changes in anthropogenic deforestation2014In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 10, no 2, p. 661-680Article in journal (Refereed)
    Abstract [en]

    This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, similar to 6 and similar to 0.2 k BP in Europe. We apply We apply the Rossby Centre regional climate model RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthropogenic land use (deforestation) from the HYDE3.1 (History Database of the Global Environment) scenario (V + H3.1), and (iii) potential vegetation with anthropogenic land use from the KK10 scenario (V + KK10). The climate model results show that the simulated effects of deforestation depend on both local/regional climate and vegetation characteristics. At similar to 6 k BP the extent of simulated deforestation in Europe is generally small, but there are areas where deforestation is large enough to produce significant differences in summer temperatures of 0.5-1 degrees C. At similar to 0.2 k BP, extensive deforestation, particularly according to the KK10 model, leads to significant temperature differences in large parts of Europe in both winter and summer. In winter, deforestation leads to lower temperatures because of the differences in albedo between forested and unforested areas, particularly in the snow-covered regions. In summer, deforestation leads to higher temperatures in central and eastern Europe because evapotranspiration from unforested areas is lower than from forests. Summer evaporation is already limited in the southernmost parts of Europe under potential vegetation conditions and, therefore, cannot become much lower. Accordingly, the albedo effect dominates in southern Europe also in summer, which implies that deforestation causes a decrease in temperatures. Differences in summer temperature due to deforestation range from -1 degrees C in south-western Europe to +1 degrees C in eastern Europe. The choice of anthropogenic land-cover scenario has a significant influence on the simulated climate, but uncertainties in palaeoclimate proxy data for the two time periods do not allow for a definitive discrimination among climate model results.

  • 19.
    Trondman, Anna-Kari
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pollen-based quantitative reconstruction of land-cover change in Europe from 11,500 years ago until present - A dataset suitable for climate modelling2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The major objective of this thesis was to produce descriptions of the land vegetation-cover in Europe for selected time windows of the Holocene (6000, 3000, 500, 200, and 50 calendar years before present (BP=1950)) that can be used in climate modelling. Land vegetation is part of the climate system; its changes influence climate through biogeophysical and biogeochemical processes. Land use such as deforestation is one of the external forcings of climate change.  Reliable descriptions of vegetation cover in the past are needed to study land cover-climate interactions and understand the possible effects of present and future land-use changes on future climate.

    We tested and applied the REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) model to estimate past vegetation in percentage cover over Europe using pollen records from lake sediments and peat bogs. The model corrects for the biases of pollen data due to intraspecific differences in pollen productivity and pollen dispersion and deposition in lakes and bogs. For the land-cover reconstructions in Europe and the Baltic Sea catchment we used 636 (grouped by 1˚x1˚ grid cells) and 339 (grouped by biogeographical regions) pollen records, respectively. The REVEALS reconstructions were performed for 25 tree, shrub and herb taxa. The grid-based REVEALS reconstructions were then interpolated using a set of statistical spatial models.

    We show that the choice of input parameters for the REVEALS application does not affect the ranking of the REVEALS estimates significantly, except when entomophilous taxa are included. We demonstrate that pollen data from multiple small sites provide REVEALS estimates that are comparable to those obtained with pollen data from large lakes, however with larger error estimates. The distance between the small sites does not influence the results significantly as long as the sites are at a sufficient distance from vegetation zone boundaries. The REVEALS estimates of open land for Europe and the Baltic Sea catchment indicate that the degree of landscape openness during the Holocene was significantly higher than previously interpreted from pollen percentages. The relationship between Pinus and Picea and between evergreen and summer-green taxa may also differ strongly whether it is based on REVEALS percentage cover or pollen percentages. These results provide entirely new insights on Holocene vegetation history and help understanding questions related to resource management by humans and biodiversity in the past. The statistical spatial models provide for the first time pollen-based descriptions of past land cover that can be used in climate modelling and studies of land cover-climate interactions in the past.

  • 20.
    Trondman, Anna-Kari
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mazier, F.
    Toulouse Univ Le Mirail, France.
    Sugita, Shinya
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Tallinn Univ, Estonia.
    Fyfe, R.
    Univ Plymouth, UK.
    Nielsen, Anne Birgitte
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University;Univ Göttingen, Germany.
    Twiddle, C.
    Univ Aberdeen, UK.
    Barratt, P.
    Queens Univ Belfast, UK.
    Birks, H. J. B.
    Univ Bergen, Norway.
    Bjune, A. E.
    Uni Res Climate, Norway;Bjerknes Ctr Climate Res, Norway.
    Bjorkman, L.
    Brostrom, A.
    Caseldine, C.
    David, R.
    Dodson, J.
    Doerfler, W.
    Fischer, E.
    van Geel, B.
    Giesecke, T.
    Hultberg, T.
    Kalnina, L.
    Kangur, M.
    van der Knaap, P.
    Koff, T.
    Kunes, P.
    Lageras, P.
    Latalowa, M.
    Lechterbeck, J.
    Leroyer, C.
    Leydet, M.
    Lindbladh, M.
    Marquer, Laurent
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund Univ.
    Mitchell, F. J. G.
    Odgaard, B. V.
    Peglar, S. M.
    Persson, T.
    Poska, A.
    Roesch, M.
    Seppa, H.
    Veski, S.
    Wick, L.
    Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling2015In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 21, no 2, p. 676-697Article in journal (Refereed)
    Abstract [en]

    We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1 degrees x1 degrees spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources.

  • 21.
    Trondman, Anna-Kari
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sugita, Shinya
    Tallinn University, Estonia .
    Björkman, Leif
    Viscum pollenanalys & miljöhistoria.
    Greisman, Annica
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tove, Hultberg
    Swedish University of Agricultural Sciences.
    Lagerås, Per
    Swedish National Heritage Board.
    Lindbladh, Matts
    Swedish University of Agricultural Sciences.
    Mazier, Florence
    Toulouse University Le Mirail, France.
    Are pollen records from small sites appropriate for REVEALS model-based quantitative reconstructions of past regional vegetation?: An empirical test in southern Sweden2016In: Vegetation History and Archaeobotany, ISSN 0939-6314, E-ISSN 1617-6278, Vol. 25, no 2, p. 131-151Article in journal (Refereed)
    Abstract [en]

    In this paper we test the performance of the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model using pollen records from multiple small sites. We use Holocene pollen records from large and small sites in southern Sweden to identify what is/are the most significant variable(s) affecting the REVEALS-based reconstructions, i.e. type of site (lakes and/or bogs), number of sites, site size, site location in relation to vegetation zones, and/or distance between small sites and large sites. To achieve this objective we grouped the small sites according to (i) the two major modern vegetation zones of the study region, and (ii) the distance between the small sites and large lakes, i.e. small sites within 50, 100, 150, or 200 km of the large lakes. The REVEALS-based reconstructions were performed using 24 pollen taxa. Redundancy analysis was performed on the results from all REVEALS-model runs using the groups within (i) and (ii) separately, and on the results from all runs using the groups within (ii) together. The explanatory power and significance of the variables were identified using forward selection and Monte Carlo permutation tests. The results show that (a) although the REVEALS model was designed for pollen data from large lakes, it also performs well with pollen data from multiple small sites in reconstructing the percentage cover of groups of plant taxa (e.g. open land taxa, summer-green trees, evergreen trees) or individual plant taxa; however, in the case of this study area, the reconstruction of the percentage cover of Calluna vulgaris, Cyperaceae, and Betula may be problematic when using small bogs; (b) standard errors of multiple small-site REVEALS estimates will generally be larger than those obtained using pollen records from large lakes, and they will decrease with increasing size of pollen counts and increasing number of small sites; (c) small lakes are better to use than small bogs if the total number of small sites is low; and (d) the size of small sites and the distance between them do not play a major role, but the distance between the small sites and landscape/vegetation boundaries is a determinant factor for the accuracy of the vegetation reconstructions.

  • 22.
    Trondman, Anna-Kari
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Sugita, Shinya
    Institute of Ecology, Tallinn University, Tallinn, Estonia .
    Mazier, Florence
    Fyfe, Ralph
    Nielsen, Anne-Brigitte
    Leydet, Michelle
    Team, LANDCLIM members
    Pollen-inferred quantitative reconstructions of Holocene land-cover in NW Europe for the evaluation of past climate-vegetation feedbacks: methods and first maps of the cover of plant functional types at 6000, 3000, 600, 200 and 0 BP2010Conference paper (Refereed)
1 - 22 of 22
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