TY - JOUR
T1 - Reconstructing land cover from pollen assemblages from small lakes in Denmark
AU - Nielsen, Anne Birgitte
AU - Odgaard, Bent Vad
N1 - Funding Information:
This study was supported by the Research Council initiative “The Agrarian Landscape in Denmark” (grant no. 9800594) and by The Danish Research Training Council. This is publication no. 9 of the project “AGRAR 2000. Danish agrarian landscapes from the birth of Christ to the year 2000” ( http://www.natmus.dk/agrar2000/ ). This is also a contribution to the NORFA network POLLANDCAL.
PY - 2005/1
Y1 - 2005/1
N2 - A calibration data set of AD 1800 pollen assemblages and land cover from
30 lake sites (3.5–33 ha) in Denmark is analysed. Canonical ordination
(RDA) shows that the distance-weighted land cover of woodland, heathland
and open field explain the highest proportion of the variation in the
pollen data. Four different distance-weighting functions, 1, 1/d, 1/d2 and an approximation of the Sugita model of pollen dispersal, are applied to the land-cover data, and the 1/d
function results in the strongest correlation between distance-weighted
land cover and pollen proportions. Partial least squares (PLS)
calibration is applied, and land cover around nine test sites (not
included in the calibration data set) is reconstructed from pollen
assemblages. The Extended R-value (ERV) model is applied to the pollen
proportions and distance-weighted plant abundance inferred from the
maps. Pollen productivity and background components are estimated from
the calibration data set and used to reconstruct plant abundance around
the test sites. The reconstructed land cover and plant abundance are
compared with historical maps, and the performance of the two models is
compared. Root-mean-squared errors for the two models are within the
same ranges but tend to be slightly lower for the ERV model. Division of
the data set into two regional subsets does not improve the
reconstructions.
AB - A calibration data set of AD 1800 pollen assemblages and land cover from
30 lake sites (3.5–33 ha) in Denmark is analysed. Canonical ordination
(RDA) shows that the distance-weighted land cover of woodland, heathland
and open field explain the highest proportion of the variation in the
pollen data. Four different distance-weighting functions, 1, 1/d, 1/d2 and an approximation of the Sugita model of pollen dispersal, are applied to the land-cover data, and the 1/d
function results in the strongest correlation between distance-weighted
land cover and pollen proportions. Partial least squares (PLS)
calibration is applied, and land cover around nine test sites (not
included in the calibration data set) is reconstructed from pollen
assemblages. The Extended R-value (ERV) model is applied to the pollen
proportions and distance-weighted plant abundance inferred from the
maps. Pollen productivity and background components are estimated from
the calibration data set and used to reconstruct plant abundance around
the test sites. The reconstructed land cover and plant abundance are
compared with historical maps, and the performance of the two models is
compared. Root-mean-squared errors for the two models are within the
same ranges but tend to be slightly lower for the ERV model. Division of
the data set into two regional subsets does not improve the
reconstructions.
KW - lakes sediments
KW - land-cover maps
KW - pollen analysis
KW - quantitative analysis
KW - reconstruction
UR - http://www.scopus.com/inward/record.url?scp=11044225827&partnerID=8YFLogxK
U2 - 10.1016/j.revpalbo.2004.08.002
DO - 10.1016/j.revpalbo.2004.08.002
M3 - Article
VL - 133
SP - 1
EP - 21
JO - Review of Palaeobotany and Palynology
JF - Review of Palaeobotany and Palynology
SN - 0034-6667
IS - 1-2
ER -