Quantitative reconstruction of past land cover in Denmark - The first results

TY - CONF

T1 -   Quantitative reconstruction of past land cover in Denmark - The first results

AU - Nielsen, Anne Birgitte

AU - Odgaard, Bent Vad

N1 - Værtspublikationsredaktører: Wahl N.A. Titel på proceedings: Department of Cicil Engeneering, Aalborg University. Abstract volume Sider: 113-113

PY - 2008

Y1 - 2008

N2 -   Pollen data are traditionally used as qualitative reflections of past vegetation cover dynamics. Such uses are based on a number of assumptions which can be shown not to be universally valid. For example, the assumption that a change in percentage frequency of a pollen type between two levels reflects a frequency change in the same direction of the mother plant may be unsubstantiated.Here, we present a first attempt at pollen based quantitative reconstruction of land cover around 9 Danish lake sites for the past 2500 years, based on models of pollen dispersal and -deposition (Prentice, 1985; Sugita, 1993, 1994), and pollen productivity estimates produced from a historical calibration dataset of AD 1800 pollen assemblages and historical plant abundance (Nielsen, 2004; Nielsen & Odgaard, 2005).  The approach circumvents many of the problems inherent in traditional interpretation of pollen records. A new model, REVEALS (Sugita 2007a), is used to reconstruct past regional abundance of the plant groups trees, grasses, cereals and heather, in 500 year intervals. These estimates are then used in the Landscape Reconstruction Algorithm, LRA, (Sugita, 2007b; Sugita, 2007c) to separate background and local pollen signals at small sites, thus providing reconstructions of local vegetation around the sites. Results reflect rather stable land cover through the last 2500 years at the regional level but strong forest-open land dynamics at the local scale. The approach should be applicable to any Quaternary pollen record provided pollen productivity estimated of major plant groups are available.Nielsen, 2004: Journal of Biogeography 31, 1693-1709.Nielsen & Odgaard, 2005: Review of Palaeobotany and Palynology 133, 1-21.Prentice, 1985: Quaternary Research 23, 76-86.Sugita, 1993: Quaternary Research 39, 239-244.Sugita, 1994: Journal of Ecology 82, 881-897.Sugita, 2007a, The Holocene 17: 229-241Sugita, 2007b, The Holocene 17: 243-257Sugita, 2007c, Encyclopedia of Quaternary Science, pp. 2561-2570

AB -   Pollen data are traditionally used as qualitative reflections of past vegetation cover dynamics. Such uses are based on a number of assumptions which can be shown not to be universally valid. For example, the assumption that a change in percentage frequency of a pollen type between two levels reflects a frequency change in the same direction of the mother plant may be unsubstantiated.Here, we present a first attempt at pollen based quantitative reconstruction of land cover around 9 Danish lake sites for the past 2500 years, based on models of pollen dispersal and -deposition (Prentice, 1985; Sugita, 1993, 1994), and pollen productivity estimates produced from a historical calibration dataset of AD 1800 pollen assemblages and historical plant abundance (Nielsen, 2004; Nielsen & Odgaard, 2005).  The approach circumvents many of the problems inherent in traditional interpretation of pollen records. A new model, REVEALS (Sugita 2007a), is used to reconstruct past regional abundance of the plant groups trees, grasses, cereals and heather, in 500 year intervals. These estimates are then used in the Landscape Reconstruction Algorithm, LRA, (Sugita, 2007b; Sugita, 2007c) to separate background and local pollen signals at small sites, thus providing reconstructions of local vegetation around the sites. Results reflect rather stable land cover through the last 2500 years at the regional level but strong forest-open land dynamics at the local scale. The approach should be applicable to any Quaternary pollen record provided pollen productivity estimated of major plant groups are available.Nielsen, 2004: Journal of Biogeography 31, 1693-1709.Nielsen & Odgaard, 2005: Review of Palaeobotany and Palynology 133, 1-21.Prentice, 1985: Quaternary Research 23, 76-86.Sugita, 1993: Quaternary Research 39, 239-244.Sugita, 1994: Journal of Ecology 82, 881-897.Sugita, 2007a, The Holocene 17: 229-241Sugita, 2007b, The Holocene 17: 243-257Sugita, 2007c, Encyclopedia of Quaternary Science, pp. 2561-2570

M3 - Poster

T2 - 28th Nordic Geological Winter Meeting

Y2 - 7 January 2008 through 10 January 2008

ER -