ecological responses to late-glacial climate changes in northern and western norway
DESCRIPTION
Ecological Responses to Late-glacial Climate Changes in Northern and Western Norway. Hilary H. Birks Steve Brooks Ingelinn Aarnes Maarten Blaauw. Bergen. London. Bergen. Belfast. INQUA 2011. - PowerPoint PPT PresentationTRANSCRIPT
Ecological Responses to Late-glacial Climate Changes in Northern and Western Norway
Hilary H. Birks
Steve Brooks
Ingelinn Aarnes
Maarten Blaauw
Bergen
Bergen
London
Belfast
INQUA 2011
There were rapid climate changes in the late-glacial (Allerød and Younger Dryas) and in the early Holocene in western Norway
• How do species and vegetation respond? Ecological processes
There is a small South-North climate gradient in Norway today; ameliorated by Gulf Stream
• Did the gradient operate during the late-glacial and early Holocene?
• Was the gradient different from that of today?
• How did these differences affect vegetation development?
Temperature was reconstructed from fossil Chironomid data from same cores as the plant data. Independent climate record.
Use plant macrofossil concentration data; local dispersal and good taxonomic resolution give evidence of local vegetation. Concentrations are independent of each other.
• Compare species and vegetation changes to temperature changes.
Fact
Fact
Method
Kråkenes
Lusvatnet
Jansvatnet
12.6oC
11oC
Arctic tree-line
Northernmost birch woodland
Sites: south to north transect
YD cirque
Steep valley with cliffs at head. Sparse birch woodland
62oN
69oN
71oN11.1oC
890 km
330 km
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal
yea
rs B
P
660
680
700
720
740
760
780800820840860880900920
940
960
Dep
th (
cm)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
Pioneer, Allerød, Younger Dryas
Kråkenes 62oN macrofossil diagram; selected taxa
OC Numbers in 100 cm3 sediment
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760
780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal year
s BP
660
680
700
720
740
760
780800820840860880900920
940
960
Depth (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
13320~100 yr
7-8
Immigration of new species after ~100 years
Earliest pioneers
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal year
s BP
660
680
700
720
740
760
780800820840860880900920
940
960
Depth (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760
780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
132808
Salix herbacea dominance
Stability of snowy mid-alpine
vegetation for 535 years
Rapid demise of pioneers
(competition)
12745
535 yr8
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760
780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal years
BP
660
680
700
720
740
760
780800820840860880900920
940
960
Depth (cm)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
13280
12745
9
61oC in 10 yr4
Allerød
Younger
Dryas
Allerød - Younger Dryas
Breakup of vegetation cover in ca. 10 years
Expansion of open ground high alpines
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760
780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal year
s BP
660
680
700
720
740
760
780800820840860880900920
940
960
Depth (c
m)
20 2 4 6 8 101214 20 40 50100150 20 40 20 20 20 1000 2000 600 20 40 60 20 20
Zone
Holocene
Allerød
Younger
Dryas
Deglaciation
KråkenesPioneer - Allerød
12745
5-6
711515
11720205
Increase in productivity
1240 yr
1oC in 205 yr
10-20 yr
High-alpine vegetation Stability for 1240 years
Unstable high-alpine landscape with glacier
Younger Dryas
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal
yea
rs B
P
660
680
700
720
740
760780800820840860880900920
940
960
Dep
th (
cm)
20 2 4 6 8 10 12 14 20 40 40 80 20 20 40 20 40 20 40 20 40 20 20
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesHolocene extinctions
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal ye
ars BP
660
680
700
720
740
760780800820840860880900920
940
960
Depth
(cm)
20 2 4 6 8 10 12 14 20 40 40 80 20 20 40 20 40 20 40 20 40 20 20
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesHolocene extinctions
Holocene
Younger Dryas - Holocene Extinctions due to rapid temperature rise
79
1151511400115 yr1oC in ~55 yr
Local extinctions of sensitive Arctic-alpines
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 10 12 14 1000 2000 300 600 20 40 60 20 20 20 40 60
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesEH expansion
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 10 12 14 1000 2000 300 600 20 40 60 20 20 20 40 60
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesEH expansion
11515
11260255 yr
7
10
10700
560 yr10
91oC in 180 yr
Early Holocene Expansions
decline
gone
1oC in ~55 yr
Grassland and dwarf-shrub heath development
Increased competition
Holocene
Expansion. Warmth tolerant, little competition
815 yr
11.5
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal ye
ars BP
660
680
700
720
740
760780800820840860880900920
940
960
Depth
(cm)
20 2 4 6 8 10 12 14 50100150 10 10 20 10 20 20 40 20 20 40 60
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesEarly Holocene immigration
r o f a
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Ca
l ye
ars
BP
660
680
700
720
740
760780800820840860880900920
940
960
De
pth
(cm
)
20 2 4 6 8 10 12 14 50100150 10 10 20 10 20 20 40 20 20 40 60
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesEarly Holocene immigration
r o f a
10000
10200
10400
10600
10800
11000
11200
11400
11600
11800
12000
12200
12400
12600
12800
13000
13200
13400
13600
Cal y
ears
BP
660
680
700
720
740
760780800820840860880900920
940
960
Dept
h (c
m)
20 2 4 6 8 10 12 14 50100150 10 10 20 10 20 20 40 20 20 40 60
Zone
Holocene
Allerød
Younger
Dryas
Degl.
KråkenesEarly Holocene immigration
r o f a
Younger Dryas
Holocene
11515
11260
10840
7
10
11.5
12
1oC in ~130 yr
1oC in ~130 yr
grasslands, wetlands, tall ferns. Immigration, Succession Competition
dwarf shrub heath. Immigration, Competition Stability 420 years
Birch woodland
Immigration, Competition, Stability 1000s years
420
675
Period Temp Rate of change length yr Plant response Vegetation
oC yr per 1oC
E Hol ~11 - 12 +/- 0 1000s Immigration, Expansion of Birch woodland 675 yr after YD-H Competition; Stability Birch woodland
E Hol 10->11.5 190 yr 300 Immigration, Expansion of Dwarf-shrub heath (Empetrum) and tall fern Stability (+Salix) dominance
E Hol 7->10 140 yr 255 Decline of remaining alpines; Extinction
Immigration of grassland and flush species, tall ferns (145 yr after YD-H), and Grassland, wetland, tall ferns
dwarf shrubs (255 yr after YD-H) Succession, Competition
YD - Hol 7->9 75 yr 10-115 Extinctions of warmth intolerant alpines (over 10-115 yr). Expansions of warmth tolerant alpines S. herbacea + alpine herb grassland
YD 5-6 0 1240 Stability High-alpine open vegetation AL – YD 6->4 10 yr 10 Rapid decline of Salix over 10 yr; Vegetation break-up
Expansion of alpine herbs High-alpine vegetation
Allerød 8 0 575 Stability Stable S. herbacea snowbed vegetation
60 S. herbacea increase over 60 yr S. herbacea dominanceCompetition
Deglac. 8 0 60 Succession Open alpine herbs; immigration Salix herbacea
Deglac. 8 0 ~100 Immigration by pioneers Open alpine herbs
9000
9250
9500
9750
10000
10250
10500
10750
11000
11250
11500
11750
12000
12250
12500
12750
13000
13250
13500
Ca
l age
BP
230
250
270
290
310330
350
370
390410430450
470
490
510
530
De
pth
cm
2 4 6 8 10 12 14 20 10 20 20 10 20 10 20 20 40 10 10 10 20 20 10 0 20 40 10 10 10 0
Zone
LUS-5
LUS-4
LUS-2
LUS-1
Lusvatnet
f a
9000
9250
9500
9750
10000
10250
10500
10750
11000
11250
11500
11750
12000
12250
12500
12750
13000
13250
13500
Cal ag
e BP
230
250
270
290
310330
350
370
390410430450
470
490
510
530
Depth
cm
2 4 6 8 10 12 14 20 10 20 20 10 20 10 20 20 40 10 10 10 20 20 10 0 20 40 10 10 10 0
Zone
LUS-5
LUS-4
LUS-2
LUS-1
Lusvatnet
f a
12450
11520
67
7-8
6 8-10
7
9
Lusvatnet 69oNAllerød Younger Dryas
12900
116507
Pioneers. Taxa of open, dry, unstable ground and some snowbeds
High-Arctic taxa of open, arid habitats
More arid
1050 yr
930 yr
9000
9250
9500
9750
10000
10250
10500
10750
11000
11250
11500
11750
12000
12250
12500
12750
13000
13250
13500
Ca
l ag
e B
P
230
250
270
290
310330
350
370
390410430450
470
490
510
530
De
pth
cm
2 4 6 8 10 12 14
Chiron
omid
infer
red
July
tem
pera
ture
20
Oxyria
dig
yna
10
Saxifr
aga
rivul
aris
20
Saxifr
aga
cesp
itosa
20
Luzu
la
10
Saxifr
aga
oppo
sitifo
lia
20
Salix
pola
ris le
af
10
Salix
herb
acea
leaf
20
Poace
ae
20 40
Brass
icace
ae u
ndiff.
10
Ceras
tium
arc
ticum
10
Braya
pur
pura
scen
s
10
Ranun
culus
glac
ialis
20
Papav
er s
ect.
Scapif
lora
20
Silene
aca
ulis
Fern
spor
angia
10
Empe
trum
nigr
um le
af
0
Betula
nan
a Σ
rem
ains
20 40
Betula
(tre
e) fr
uit
10
Filip
endu
la ulm
aria
10
Nitella
10
Chara
0
Isoet
es sp
p.
Zone
LUS-5
LUS-4
LUS-2
LUS-1
Lusvatnet
f a
9000
9250
9500
9750
10000
10250
10500
10750
11000
11250
11500
11750
12000
12250
12500
12750
13000
13250
13500
Ca
l ag
e B
P
230
250
270
290
310330
350
370
390410430450
470
490
510
530
De
pth
cm
2 4 6 8 10 12 14
Chirono
mid in
ferre
d Ju
ly te
mper
atur
e
20
Oxyria
dig
yna
10
Saxifra
ga ri
vular
is
20
Saxifra
ga ce
spito
sa
20
Luzu
la
10
Saxifra
ga o
ppos
itifoli
a
20
Salix p
olaris
leaf
10
Salix h
erbac
ea lea
f
20
Poacea
e
20 40
Brass
icace
ae un
diff.
10
Cerasti
um a
rctic
um
10
Braya
pur
pura
scen
s
10
Ranunc
ulus g
lacialis
20
Papave
r sec
t. Sca
piflor
a
20
Silene
acau
lis
Fern sp
oran
gia
10
Empe
trum
nigru
m le
af
0
Betula
nana
Σ re
mains
20 40
Betula
(tree
) fru
it
10
Filipend
ula ulm
aria
10
Nitella
10
Chara
0
Isoet
es sp
p.
Zone
LUS-5
LUS-4
LUS-2
LUS-1
Lusvatnet
f a
9000
9250
9500
9750
10000
10250
10500
10750
11000
11250
11500
11750
12000
12250
12500
12750
13000
13250
13500
Cal ag
e BP
230
250
270
290
310330
350
370
390410430450
470
490
510
530
Depth
cm
2 4 6 8 10 12 14 20 10 20 20 10 20 10 20 20 40 10 10 10 20 20 10 0 20 40 10 10 10 0
Zone
LUS-5
LUS-4
LUS-2
LUS-1
Lusvatnet
f a
11520
10520
79.5
11.510
12
1000 yr
Lusvatnet Early Holocene
Persisting Arctic- alpines
Birch woodland with ferns and herbs
ImmigrationStability
Dwarf shrub heath/ferns
Dramatic decline in Arctic-Alpines
725075007750800082508500875090009250950097501000010250105001075011000112501150011750120001225012500127501300013250
Cal ye
ar BP
1140
1150
1160
1170
1180
1190
1200
1210
1220
123012401250126012701280
1290
1300
Depth
cm
2 4 6 8 10 12 14 0 20 20 20 20 40 20 50 100 150 200
Zone
JM 1b
JM 1c
JM 2
JM 3
JM 4
JM 5
Jansvatnet
f a
725075007750800082508500875090009250950097501000010250105001075011000112501150011750120001225012500127501300013250
Ca
l ye
ar
BP
1140
1150
1160
1170
1180
1190
1200
1210
1220
123012401250126012701280
1290
1300
De
pth
cm
2 4 6 8 10 12 14
Chiro
nom
id-in
ferre
d Ju
ly te
mpe
ratu
re
Saxifr
aga
rivula
ris
Salix p
olaris
leaf
Luzu
la
0
Dryas
oct
opet
ala
Fern
spor
angi
a
20
Empe
trum
seed
20
Empe
trum
leaf
Betula
nan
a Σ re
main
s
Vaccin
ium
20
Vaccin
ium m
yrtill
us/u
ligin
osum
ant
her
20 40
Betula
(tre
e) fr
uits
20
Betula
(tre
e) fe
mal
e ca
tkin
scale
50 100 150 200
Nitella
Ranun
culu
s sec
t. Bat
rach
ium
Zone
JM 1b
JM 1c
JM 2
JM 3
JM 4
JM 5
Jansvatnet
f aAL
YD
Hol
6-8
7
4-8
4
910
11650
12760
1oC in ~40 yr
1oC in ~75 yr
1oC in ~100 yr
10750
900
Jansvatnet 71oN
Late glacial
12400
Sparse pioneer vegetation - arid
No macros; lake turbid (YD)
Sparse pioneer vegetation – very arid
Warming (lake), no terrestrial response
Dwarf-shrub heath devel.
300
Rapid response threshold
Increased oceanicity
725075007750800082508500875090009250950097501000010250105001075011000112501150011750120001225012500127501300013250
Ca
l ye
ar
BP
1140
1150
1160
1170
1180
1190
1200
1210
1220
123012401250126012701280
1290
1300
De
pth
cm
2 4 6 8 10 12 14
Chiro
nom
id-in
ferre
d Ju
ly te
mpe
ratu
re
Saxifr
aga
rivula
ris
Salix p
olaris
leaf
Luzu
la
0
Dryas
oct
opet
ala
Fern
spor
angi
a
20
Empe
trum
seed
20
Empe
trum
leaf
Betula
nan
a Σ re
main
s
Vaccin
ium
20
Vaccin
ium m
yrtill
us/u
ligin
osum
ant
her
20 40
Betula
(tre
e) fr
uits
20
Betula
(tre
e) fe
mal
e ca
tkin
scale
50 100 150 200
Nitella
Ranun
culu
s sec
t. Bat
rach
ium
Zone
JM 1b
JM 1c
JM 2
JM 3
JM 4
JM 5
Jansvatnet
f a
725075007750800082508500875090009250950097501000010250105001075011000112501150011750120001225012500127501300013250
Cal y
ear B
P
1140
1150
1160
1170
1180
1190
1200
1210
1220
123012401250126012701280
1290
1300
Depth
cm
2 4 6 8 10 12 14 0 20 20 20 20 40 20 50 100 150 200
Zone
JM 1b
JM 1c
JM 2
JM 3
JM 4
JM 5
Jansvatnet
f a
725075007750800082508500875090009250950097501000010250105001075011000112501150011750120001225012500127501300013250
Cal
yea
r BP
1140
1150
1160
1170
1180
1190
1200
1210
1220
123012401250126012701280
1290
1300
Dep
th c
m
2 4 6 8 10 12 14 0 20 20 20 20 40 20 50 100 150 200
Zone
JM 1b
JM 1c
JM 2
JM 3
JM 4
JM 5
Jansvatnet
f a
JansvatnetHolocene
11
12
12
10100
9350
750 yr
10-11.5
Birch woodland + ferns and dwarf shrubs (1550 yr)
Birch at tree-line;
increased windiness
10750650 yr Dwarf shrub heath
Tipping point
900 yr
Increasing oceanicity
Stability
AL temp AL-YD fall
rate
Jans 11.1oC 6-8oC 0 -
Lus 11oC 7-8oC 0 -
Kråk
12.6oC 8-9oC 3oC 1oC in 75 yr
Rapid 2oC cooling at 12745 BP
Comparison of temperatures and rates; AL-YD
Climatic boundary
Kråkenes
Lusvatnet
Jansvatnet
890 km
330 km
AL gradient stronger than today YD north-south contrast - aridity
Mid YD Cooling
YD temp YD – Hol rise
Initial rate
Temp at birch establishment
Jans 11.1oC
Rapid 3oC cooling at 12400 BP
aridity
4-7oC 5oC 1oC in 50 yr
12oC
Lus 11oC
Rapid 2oC cooling at 12450 BP
aridity
7-8oC 2.5o rapid 11oC
Kråk 12.6oC - 5oC 2oC 1oC in
55 yr11oC
Comparison of temperatures and rates YD, Holocene
AL YD E Hol Dwarf shrub heath
Time to Birch woodland
Jans 11.1oC
High alpine – very arid S. polaris
High alpine – very arid S. polaris
Poor dwarf-shrub heath
1550 yr (Declined after 750 yr; 9350
cal yr BP)
Lus 11oC
High alpine – arid S. polaris
High alpine – very arid S. polaris
Poor dwarf-shrub heath 1000 yr
Kråk 12.6oC
snowbeds
Mid alpine
S. herbacea
Wet
High alpine (glacier) S. herbacea
Strong Empetrum heath after
255 yr
675 yr
Comparison of Vegetation
• Drivers of vegetation changes are Temperature and Precipitation (affected by sea-ice cover)
AL YD EH Birch
J V. Cold Arid
V. Cold
V. Arid
Arid to oceanic
Oceanic
L Cold Dry
Cold Arid
Arid to oceanic
Oceanic
K Cool
Wet
Cold Wet (glacier)
Oceanic Oceanic
• The absolute climate values, the changes, and the balances between them determine vegetation development through: Immigration Expansion Competition Extinction
• Under constant climate conditions, vegetation may show: Succession Immigration Competition Stability
Emerging pattern
Increasing aridity
Small gradient, as today
Temperature Temperature PrecipitationPrecipitation
dry
warm
cold
wet
GoGoArriveArrive StayStay
T i m e
ImmigrationImmigration
Evolution
CompetitionCompetition
SuccessionSuccession
Extinction