Past and future changes in alpine tundra
in the Rocky Mountains (CO)
Chris RANDIN, Hope HUMPHRIES (INSTAAR, CO), Nigel YOCCOZ
(Uni.Tromsø, Norway) & Katie SUDING (UCI, CA)
With the collaboration of
Glen LISTON & Christopher HIEMSTRA (CIRA, CO)
Silverton CO, June 12th 2008
MTNCLIM08 conference
Context of the study: A warming world
IPCC (2007)
Projected warming for 2055 (A1FI; average of five AOGCM) in
mountain regions
Silverton
CO
Photo: C.Randin
Warming (°C)
0.75 - 2
2-3
3-4
4-5
5-7
+
Nogués-Bravo, D., et al. (2007) Global Environmental Change
Context of the study: A warming world
Temperature anomalies for the 20st century
1900
1920
1940
1960
1980
2000
1.5
Sw it zerland
1
0.5
0
-0.5
-1
Nort hern
hemisphere
Château-d’Oex – Western Sw iss Alps
NOAA; Rebetez and Reinhard (2007) Theoretical and Applied Climatology;
Vittoz, Randin, Dutoit & Hegg (in revision) Global Change Biology
Photo: C.Randin
Early 2000’s: just climatic records ?...
Or the foretaste of the future?
Last decade in Silverton or in the Alps
Decadal rate of temperature increase:
0.6-0.8°C / 10 years Ö ~ +6 to +8°C end of 21st century
IPCC (2007)
How do mountain plants react to
climate change?
Persist and adapt
(phenotypic /
genotypic
plasticity)
Adapted for
dispersal
“Migration” of
seeds
Stay and get
extinct
Sessile (/stupid?)
organisms
Adapted for
dispersal +
Ability to track
suitable habitats
Migration +
colonization
Photo: C.Randin, M.Rebetez
Aim of the study
1. Assessing the changes in alpine plant
species cover and distribution from 1989 to
2006
– At a landscape level
–At the community level
–At the species level
If changes are related with climate:
2. Projecting plant species distribution in a
future changing climate
Fine scale / high resolution studies are required in
the alpine !
Lassueur T., Joost S. and Randin C. (2006) Ecological Modelling;
Randin C., Engler R., Poulsen S., Zappa M., Zimmermann N., Pearman P., Vittoz, Thuiller W. et
Guisan A. (in revision) Global Change Biology
Methods
• Dataset of plant species distribution at a fine scale and
at different time steps (1989,1990,1995,1997,2006)
• Geographic variables of direct / resource gradients
(sensu Austin 2006: snow, moisture,...)
• Comparisons with experimental studies in alpine
systems
79 plots
79 plots
79 plots
75 species
Species
dataset75 species
Species
1989
dataset
75 species
Species
1990
dataset75 species
Species
1995
dataset
Species
1997
dataset
2006
79 plots
79 plots
75 species
Methods
The Saddle gridded dataset on Niwot Ridge
N
Elevation: 3500m
Methods
Dominant wind
direction
50m
350m
500m
N
Methods
350m
500m
N
Methods
Classification of vegetation units
4
2
18
48
9
39
40
30
401
78
69
801
50
601
701
59
70
501
79
80
11
60
75
49
58
51
19
29
10
20
101
201
52
57
77
68
7
47
66
55
65
74
76
37
56
54
32
35
34
33
5
15
16
24
6
12
31
45
21
23
14
62
3
61
72
73
2
67
8
53
25
64
27
26
4
17
43
44
36
22
46
Height
6
8
Cluster Dendrogram
0
Average of species coverage
1989-2006
Distance: Bray (to deal with double zero)
Grouping method: Ward (minimize intra-class variance)
Methods
Snowbed
Dry meadow
xeric to mesic
150-200 d snow free
Later-melting snow patches
<75 d snow free
Kobresia myosuroides
Sibbaldia
procumbens/
Carex pyrenaica
Fellfield
Moist meadow
Earlier-melting snow
patches
100-150 d snow free
Acomastylis rossii /
Deschampsia
caespitosa
Wet meadow
subhygric
(snow) marsh communities
Snow free period varies
Wind-exposed, xeric to
subxeric
>200 d snow free
Carex rupestris /
Silene acaulis
Caltha leptosepala / Carex
scopulorum
Walker et al. 1993 BioScience
Trend (°C yr-1)
Trend (°C yr-1)
Adj. R2=0.53; P<0.001
P<0.05
Adj. R2=0.43; P<0.001
Adj. R2=0.55; P<0.001
Trend (mm yr-1)
Trend (°C yr-1)
Local climatic facts
Adj. R2=0.32; P=0.001
Data from Ken Hill (2008) Master thesis
Methods
D1
75th percentile
Ken Hill (2008) Master thesis
Methods
Earlier Snowmelt 2-6 days decade-1!
Ken Hill (2008) Master thesis
Landscape level
Partial Triadique Anaylisis (PTA)
d=5
Interstructure
Compromise - Plots
864 72
46
2 7352
2236
53
25
67
23
27
24
6
26
44
51615
43
4
17 75
49
31
762
33
57
14
74
32
60
214712
35
45
34
77
55
546880
65
76
79 58
1151
66
56
29
19
20
10
101
201
3
61
Saddle.1990
Saddle.1989
78
Saddle.1995
Saddle.1997
Saddle.2006
50
30
Eigenvalues
Eigenvalues
501 70169801
601
401
59
40 39 70 18
9
48
d = 100
Compromise - Species
DESCAE
TRIPAR
SIBPRO
ARTSCO
CARSCO
EPIANG
BISBIS
CALLEP
CASOCC
POAARC
ERISIM
FESBRA
CARPYR
RANADO
JUNDRU
GENALG
MINOBT
CHIJAM
LEWPYG
SALARC
CLERHO
CARLAC
OXYDIG
PEDGRO
CARALB
CARELY
SENFRE
STELON
CARCAP
DRACAN
DRAAUR
POTDIV
POLVIS
POAGLA
SOLMIS
CARNIG
MERVIR
PHLALP
PRIPAR
SALPLA
PEDPAR
SOLMUL
RHOINT
SALNIV
TRISPI
ERIMEL
MERLAN
LUZSPI
PARPUL
SAXRHO
AREFEN
POAALP
PHLSIB
ERIPIN
SALGLA
SILACA
BISVIV
LLOSER
TRIDAS
AGRTRA
DRASTR
THLMON
SEDLAN
ANTALP
PRIANG
ERIARE
TRINAN
HYMGRA
HYMACA
CAMUNI
CALPUR
OREALP
x1
CARRUP
KOBMYO
ACOROS
Slight change
but (hopefully) directional (!)
in species cover and
composition from 1989 to 2006
Community level
Factorial Analysis (FA)
Axe 1= 19%; Axe 2 = 16%
90-95
3
3
3
Axes 1&2
MM
Veg units
DM
0
0
1
1
2
Axes 1&2
2
1
0
SB
2
Snowbed
Dry meadow
Axes 1&2
97-06
95-97
SB
MM
Veg units
DM
SB
MM
Veg units
DM
Community level
Increase of the intensity of change…
But not uni-directional
5.97
5.06
15.97
15.06
0.5
3
3
1.0
Axe 1= 19%; Axe 2 = 16%; Axe 3 = 13%
33.06
16.97
16.06
35.97
11.97
0.0
-0.5
1
-1.0
SB
97.06
35.06
34.97
6.97
34.06
6.06
33.97
14.97
62.06
14.06
45.97
62.97
12.97
32.97
24.06
24.97
11.06
21.06
21.97
12.06
66.97
Changes in plot
species (projection
along FA axis 1 & 2)
45.06
31.97
31.06
1997-2006
66.06
-1.5
95.97
65.97
55.06 65.06
32.06
0
90.95
54.06
54.97
CA2
2
Axes 1&3
2
1
0
Axes 1&2
55.97
90.95
95.97
SB
97.06
-2.0
-1.5
-1.0
CA1
-0.5
0.0
0.5
Species level
The Kobresia story in the dry meadow
Kobresia myosuroides
1988-1997 normal-wet period?
Bell & Bliss (1979) Ecol. Monogr.; Bowman (2000) AMBIO
Species level
The Caltha story in the moist meadow
Living on the edge
Caltha leptosepala
2000-2003 dry period (decrease in
snowpack) + high T°?
Moist meadow
plots
Delta snowpack
1997-2006
3y mean
Species level
The Sibbaldia story in the snowbed
Delta snowpack
1995-1997
3y mean
Sibbaldia procumbens
1. High temperature + thick snowpack?
2. Thin snowpack Ö exposed to frost?
1
2
Delta 1995-1997
3y mean
Delta snowpack
Delta 1997-2006
1997-2006
3ymean
mean
3y
Species level
The Carex pyrenaica story in the snowbed
Carex pyrenaica
R2 = 0.39
P = 0.009
R2 = 0.59
P = 0.006
Species Distribution Models (SDM) for the
future
Snowcover
Species
coverage ~
Nutrients
Soil moisture
30% decrease
AIC-based stepwise GLM (Gaussian) with
quadratic term allowed for each predictor
Kobresia myosuroides
Range expands
Nagelkerke R2: 0.6
Sibbaldia procumbens
Nagelkerke R2: 0.3
Range shrinks
% cover
Low
High
Concluding remarks
1. Ecologically meaningful / Mechanistic
relationships between change in climate
and vegetation
However, stronger statistical relationships are required:
Ö Multivariate models, spatially constraints analysis,
MC simulations
Ö Dynamic simulations of snow distribution to get
more predicting variables (complete series of
snowpack, moisture, T°)
2. At the community and species level, this
alpine system may react quickly to change
in temperature, precipitation and snowpack
From Hill (2008) Master thesis
N loading increases, despite drought events
Thanks for your attention!
Questions?
Aim of the study
Empirical studies of past
vegetation change in the
Alps
De Candolle
School
140
Nb of species
120
100
1st inventory (~1900)
Recent inventory
(~2000)
Linear trend (~1900)
80
Linear trend (~2000)
60
40
20
0
2700
2800
2900
3000
3100
3200
3300
3400
3500
Altitude [m]
Monitoring of summits in the Swiss / Austrian Alps year 1900 Ö 2000
Photo: C.Randin
Vittoz et al. (in prep); Grabherr & al. (1994) Nature
Aim of the study
Process-based studies
in the Rockies
Ö Link in situ observations with process-based
studies
de Valpine & Harte (2001) Ecology; Theodose & Bowman (1997) Ecology