Period 9

1
Modelling the pollen signal from principal
landscape development
Per Sjögren Brigitta Ammann, Institute of Plant
Sciences University of Berne, www.botany.unibe.ch
The pasture woodland of the Jura Mountains is a
mosaic landscape consisting of forests, wooded
pastures and open pastures, created by centuries
of summer farming. Pollen analyses from peat
profiles in the valley Combe des Amburnex
indicate an opening up of the central parts of
the valley in the 12th century and of the more
periphery areas in the 17th century.
Simulating different principal dynamics for the
opening (or closing) of the landscape improves
the interpretation of the fossil pollen
record. In the example (upper left) the pollen
assemblage is simulated in two basins (central
r100m, peripheral r10m). An open and a
half-open area around the central basin is set to
increase. Principal similarities and
dissimilarities with the fossil record (lower
left) can be assessed and improve further
interpretation.
Poacea/herbs, Peripheral
Abies/Fagus, Peripheral
Poaceae/herbs, Central
Abies/Fagus, Central
Picea, Peripheral
Picea, Central
X-value
Abies/Fagus 67, Picea 33
600
550
500
Picea 50, Poaceae 50
450
400
Poaceae 100
350
300
X
X
250
200
150
100
50
0
20
40
60
80
100
20
40
60
80
100
Poaceae/Herbs, Amb
Poaceae/Herbs, Gim
Abies/Fagus, Amb
Abies/Fagus, Gim
Picea, Amb
Picea, Gim
Period 9
1975-2000 AD
Period 8
1950-1975 AD
The simulation is made with Mosaic v1.1 and
Polflow v1.0 (Middleton and Bunting, in press).
Parameters are pollen fall speed all taxa 0.05
Pollen production Abies/Fagus 1, Picea 2,
Poaceae/Herbs 1 grid 3x3km distance between
centre of basins 500m x increase in 50m steps
otherwise default settings.
Gim
Period 7
1900-1950 AD
Period 6
1800-1900 AD
Period 5
1650-1800 AD
Period 4
1300-1650 AD
Period 3
850-1300 AD
Amb
Period 2
0-850 AD
20
40
60
80
100
20
40
60
80
100