Climate change in unpredictable terrestrial
ecosystems: an integrative approach along an
aridity gradient in Israel
Marcelo Sternberg
Department of Molecular Biology & Ecology of Plants
Tel Aviv University, Israel
GLOWA – Jordan River
Soil moisture
Climate change
Land use change
GLOWA
+&feedbacks
Global water cycle
Evapo-transpiration
& evaporation
Water vapor (dew
& air humidity
Water cycle: dominant cause of uncertainty in climate change
projections
Green water: terrestrial ecosystems
Precipitation–the basic water resource
GW
GW
GW
GW
GW
Falkenmark 2003
GLOWA – Jordan River
What will happen to natural ecosystems and
their “users”?
Or….
Being a prophet in the
“Land of Prophets”……
………a tough job
Research partners
Alon Angert, Jose Gruenzweig, Jaime Kigel, Irit Konsens
The Hebrew University of Jerusalem, Israel
Yossi Steinberger
Bar-Ilan University, Israel
Katja Tielboerger
Tuebingen University, Germany
Global Climate Change in the Middle East
Current global climate change
models predict changes in
temperature and rainfall in the
Mediterranean basin region.
Higher summer &
autumn temperatures
Lower winter rainfall
Black, 2009; Klafe & Bruins, 2009
Study sites
The gradient:
Arid
Semiarid
Mediterranean
Mesic
Mediterranean
Rainfall (mm)
Rainfall along
the aridity
gradient
Source: IMS
Rainfall CV (%)
Rainfall
predictability
along the aridity
gradient
Source: IMS
Aridity gradient
Topography
South-facing slopes
with stony and shallow
soil (Terra rossa to
desert lithosol on hard
limestone and chalk)
Mediterranean - 540 mm – CV 30%
~ 245
km
Mesic Mediterranean - 780 mm – CV 22%
Semiarid – 300 mm – CV 37%
Arid – 90 mm – CV 51%
Temperature
Mean annual
temperature 180C-190C
Rainfall
Mainly winter - 5
summer months with
no rainfall
Range North-South:
780 to 90 mm
Rainfall along the gradient
800
Rainfall (mm)
700
795 mm
Mesic Mediterranean
Mediterranean
Semiarid
Arid
609 mm
600
500
400
270 mm
300
200
100 mm
100
0
Oct-06
Dec-06
Feb-07
Apr-07
Jun-07
Aug-07
Oct-07
Date
Differences in length of the growing season
Talmor et al., 2010 GCB
Experimentally testing the effects of
climate change
Rainout Shelters (25 x 10 m) –
30% reduction
Sprinkler Irrigated Plots
(25 x 10 m) – 30% increase
Experimental design
N
Supplemented
rainfall
Mesic
Mediterranean
780 mm
Mediterranean
540 mm
Semiarid
300 mm
Arid
90 mm
Drought
Experimental design
N
Supplemented
rainfall
EIN - Mesic
Mediterranean
780 mm
MAT
Mediterranean
540 mm
LAH
Semiarid
300 mm
SDE
Arid
90 mm
Drought
Data collection – Gradient vs. manipulation data
Gradient
Rainfall manipulations
Vegetation
NPP
Species richness
Species diversity
Soil seed banks
Seedling mortality
Vegetation
NPP
Species richness
Species diversity
Soil seed banks
Seedling mortality
Ecosystem
Soil respiration
NO3, NH4 & PO4
P (d18Op )
Soil microbial biomass
Soil Fungi
Plant root and litter
decomposition
Ecosystem
Soil respiration
NO3, NH4 & PO4
P (d18Op )
Plant litter decomposition
Soil mesofauna
Ground insect (beetles)
Soil mesofauna
Ground insects (beetles)
Results
The gradient:
Arid
Semiarid
Mediterranean
Mesic
Mediterranean
Soil nutrients along the gradient
NO3- increased with increasing rainfall – P decreased at the most
mesic site – seasonal changes
Arid
Semiarid
Mediterranean
NO3- - Control
P - Control
35
120
30
100
25
20
80
mg/kg
mg/kg
140
15
60
10
40
5
20
0
Sep-07
Mesic Med.
Mar-08
Sep-08
Mar-09
Sep-09
Mar-10
Time
0
Sep-07
Mar-08
Sep-08
Mar-09
Sep-09
Mar-10
Soil nutrients along the gradient
N and OC increases with increasing rainfall – seasonal changes
Arid
Semiarid
Mediterranean
Mesic Med.
OC - Control
N - Control
3,5
0,6
3
0,5
2,5
2
%OC
%N
0,4
0,3
1,5
0,2
1
0,1
0
Sep-07
0,5
Mar-08
Sep-08
Mar-09
Sep-09
Mar-10
Time
0
Sep-07
Mar-08
Sep-08
Mar-09
Sep-09
Mar-10
Primary productivity along the gradient
Linear relationship between annual rainfall and herbaceous
biomass production until 450 mm
Arid
Semiarid
Mediterranean
Mesic Med.
350
300
g/m2
250
200
150
100
50
0
0
200
400
600
800
1000
1200
Rainfall (mm/yr)
Kigel et al., unpublished
Species richness along the gradient
No linear relationship between rainfall & spp. richness at the
mesic sites
Arid
Semiarid
Mediterranean
Mesic Med.
2006
5
2009
8
Species richness (20 x 20 cm)
70
60
50
40
30
20
10
0
0
2002
1
2003
2
2004
3
2005
4
2007
6
2008
7
2010
9
10
Year
Kigel et al., unpublished
Species richness and rainfall along the gradient
Species richness (20 x 20 cm)
Arid
Semiarid
Mediterranean
Mesic Med.
80
70
60
50
40
30
20
2010 y = -0.0001x2 + 0.1973x - 5.1043
R2 = 0.926 R = 0.96228
10
0
0
200
400
600
800
1000
1200
Rainfall (mm/yr)
Kigel et al., unpublished
Species richness & APP correlation along the
gradient
Arid
Semiarid
Mediterranean
80
Species richness (20 x 20 cm)
80
Species richness (20 x 20 cm)
Mesic Med.
70
60
50
40
30
20
2010 y = -0.0001x2 + 0.1973x - 5.1043
R2 = 0.926 R = 0.96228
70
60
50
40
30
10
10
0
0
0
200
400
600
800
Rainfall (mm/yr)
1000
1200
2010 y = -0.0004x2 + 0.3132x + 8.7887
R2 = 0.8325 R = 0.9124
20
0
50 100 150 200 250 300 350 400 450 500 550 600 650
Biomass DW (gr/m2)
Kigel et al., unpublished
Soil seed bank
Mean No of seedlings (m-2)
Changes in seed bank density along the aridity
gradient
35000
Station ***
Year ***
S x Y ***
30000
25000
20000
15000
10000
5000
0
2001
2002
2003
2004
2005
Year
arid
semiarid
Mediter.
mesic
Mediter.
2006
2007
2008
2009
Important differences
among sites & years
Strong densities variation
with rainfall at the mesic
sites
Changes in community structure along the
aridity gradient
Species diversity (H’)
50
Species richness
Station ***
Year ***
S x Y ***
40
4
Station ***
Year ***
S x Y **
3,5
3
2,5
30
20
2
1,5
10
1
0,5
0
0
arid
semiarid
Mediter.
mesic
Mediter.
Species evenness (J’)
2001 2002 2003 2004 2005 2006 2007 2008 2009
2001 2002 2003 2004 2005 2006 2007 2008 2009
Important
differences among
sites.
1
0,9
0,8
0,7
0,6
0,5
0,4
Station ***
Year ***
SxY **
0,3
0,2
0,1
0
2001 2002 2003 2004 2005 2006 2007 2008 2009
Year
No linear relation
between rainfall and
spp. richness &
diversity.
Decreasing trend of
spp. richness at the
more mesic sites
Experimentally testing the effects of
climate change
Rainout Shelters (25 x 10 m) –
30% reduction
Sprinkler Irrigated Plots
(25 x 10 m) – 30% increase
Climate treatment effects on primary productivity
Rainfall manipulations had a significant effect on biomass
production at the semiarid station only
Mediterranean
Semiarid
Drought
350
300
Control
Watering
Year ***
Treatment **
T x Y NS
Drought
Rain
350
350
300
Control
Watering
Rain
Year ***
Treatment NS
T x Y NS
800
700
250
250
200
200
150
150
100
600
500
250
g/m2
g/m2
300
400
200
300
100
200
150
50
50
0
100
0
100
2003 2004 2006 2007 2008 2009 2010
0
2003 2004 2006 2007 2008 2009 2010
Year
Kigel et al., unpublished
Climate treatment effects on primary productivity
Effective rainfall manipulations had a significant effect on biomass
production at the semiarid station only
Semiarid
Control
Watering
Mediterranean
Drought
Control
250
Drought
Watering
350
200
300
R² = 0.748 p=0.01
R² = 0.525 p=0.05
150
g/m2
g/m2
250
100
200
R² = 0.794 p<0.01
50
150
0
50
150
250
Rainfall (mm/yr)
350
450
100
200
400
600
800
1000
Rainfall (mm/yr)
Kigel et al., unpublished
1200
Effects of rainfall manipulations on seed bank
density
Semiarid
25000
450
Treat. NS
Year ***
T x Y NS
900
Treat. NS
Year ***
T x Y NS
400
800
20000
20000
350
700
600
15000
300
15000
250
200
10000
150
400
10000
100
5000
200
50
100
5000
0
0
500
300
0
2003 2004 2005 2006 2007 2008 2009
0
2003
Year
drought
control
watering
rainfall
2004
2005
2006
2007
2008
2009
Rainfall (mm)
25000
Mean No of seedlings (m-2)
Mediterranean
No treatment effect on seed bank density
Semiarid
25000
450
Treat. NS
Year ***
T x Y NS
900
Treat. NS
Year ***
T x Y NS
400
800
20000
20000
350
700
600
15000
300
15000
250
200
10000
150
400
10000
100
5000
200
50
100
5000
0
0
500
300
0
2003 2004 2005 2006 2007 2008 2009
0
2003
Year
drought
control
watering
rainfall
2004
2005
2006
2007
2008
2009
Rainfall (mm)
25000
Mean No of seedlings (m-2)
Mediterranean
Effects of rainfall manipulations on community
structure – Mediterranean site
4,5
800
4
700
Species richness
35
900
30
600
25
500
20
400
15
300
10
200
5
100
0
0
Treat. NS
Year ***
T x Y NS
900
800
3,5
700
3
600
2,5
500
2
400
1,5
300
1
200
0,5
100
0
2003 2004 2005 2006 2007 2008 2009
0
2003 2004 2005 2006 2007 2008 2009
Year
drought
control
watering
rainfall
Rainfall (mm)
40
Treat. NS
Year ***
T x Y NS
Species diversity (H’)
45
No rainfall manipulations effects on community
structure – Mediterranean site
4,5
800
4
700
Species richness
35
900
30
600
25
500
20
400
15
300
10
200
5
100
0
0
Treat. NS
Year ***
T x Y NS
900
800
3,5
700
3
600
2,5
500
2
400
1,5
300
1
200
0,5
100
0
2003 2004 2005 2006 2007 2008 2009
Rainfall (mm)
40
Treat. NS
Year ***
T x Y NS
Species diversity (H’)
45
0
2003 2004 2005 2006 2007 2008 2009
Year
drought
control
watering
rainfall
Similar results at the
semiarid site
Effects of rainfall manipulations on insect
density
Shtirberg et al., unpublished
Effects of rainfall manipulations on insect
density
Semiarid
Treat. NS
Year ***
T x Y NS
1400
Mean No of insects
Mediterranean
1200
1200
1000
1000
800
800
600
600
400
400
200
‘06 ‘07
‘06 ‘07
‘06 ‘07
0
200
0
Drought
Control
Treatment
Watering
Treat. NS
Year ***
T x Y NS
1400
‘06 ‘07
Drought
‘06 ‘07
Control
‘06 ‘07
Watering
Treatment
Shtirberg et al., unpublished
Rainfall, soil moisture & soil respiration
Rs (µmol CO2 m-2 s-1)
90
40
80
Mediterranean
Open
35
70
30
60
25
50
20
40
15
30
10
20
5
10
0
0
10
Rainfall (mm)
Volumetric SWC (%)
45
Wet
Control
Dry
8
6
4
Talmor et al., 2011
2
GCB
0
Jan-06
Apr-06
Jul-06
Oct-06
Jan-07
Apr-07
Jul-07
Oct-07
Soil respiration & rainfall manipulations
1000
Rs (g C m-2 y-1)
800
p<0.05
Wet
Control
Dry
A
AB
B
600
400
200
0
Open
Shrub
Mediterranean
Open
Shrub
Semiarid
Talmor et al., 2010
Effects of rainfall manipulations on soil microbial
biomass
Microbial biomass (µg C g soil-1)
Semiarid
2008
2009
Mediterranean
Autumn
Winter
Spring
Summer
2008 & ‘09 Seasons & Treatments
Season – significant changes
No consistent pattern of treatment response
Sherman et al., unpublished
Conclusions
1) Soil nutrients, primary productivity, soil seed bank (SSB)
density, species richness, species diversity varies
strongly along the aridity gradient
2) No linear relationship between rainfall, NPP and species
richness – P limitation at more mesic ecosystems?
3) Seed density correlates rainfall amounts (resource
availability) along the aridity gradient, however
differences among years are not necessarily reflected in
higher number of seeds
Conclusions
4) The rainfall manipulations have not led to the
hypothesized changes in soil properties, species density
and community structure of the soil seed bank & insects.
Plant communities proved to be resistant to this shortterm climatic changes, particularly to drought. Increase
of NPP at the semiarid indicates release of limiting
factor.
5) We assume, that community resistance is mainly due to
the vegetation “adaptation” to high temporal variability
in rainfall, combined with high spatial heterogeneity.
These characteristics buffers short-term changes.
Conclusions
7) Ecosystem level response (SR) to the rainfall
manipulations indicates a different scale of response.
Soil biota may respond faster to changes (i.e. higher
generation turnover)
8) The detected short-term resistance does not
necessarily imply resistance to long-term global climate
change. More years are needed…..
Conclusions
Eastern Mediterranean ecosystems have evolved
under high climatic variability conditions, high
levels of stress and perturbations – Ecosystems
characterized by high spatial & temporal variability
Does this make them less vulnerable to climate
change?
In press GCB
Take home message
Vulnerability to climate change
decreases with increasing long-term
climatic variability
Thanks!!
Questions?
MarceloS@tauex.tau.ac.il
ᵦ species diversity – changes is composition
similarity between stations and years
βsim (Simpson's based; reduces biases from imbalances in species
richness between samples)
Similarity in species composition between and among stations
decreased with time at the arid sites
Arid ‘02
Arid ‘02
Semiarid ‘02 Medit. ’02 M. Med ‘02
Arid ‘07
Semiarid ‘07 Med. ‘07
M. Med ‘07
-
Semiarid ‘02
0.57
-
Medit. ‘02
0.39
0.64
-
Mesic Med ‘02
0.43
0.55
0.64
-
Arid 2007
0.39
0.65
0.57
0.39
-
Semiarid ’07
0.39
0.74
0.62
0.57
0.70
-
Medit. ’07
0.32
0.55
0.67
0.56
0.52
0.67
-
M. Med ‘07
0.21
0.44
0.62
0.69
0.43
0.45
0.63
-
Soil fungi species richness along the gradient
Soil fungi species richness (gr)
Arid
Semiarid
Mediterranean
Mesic Med.
40
30
20
10
0
Winter'08 Spring'08 Summer'08
Fall'08
Winter'09 Spring'09 Summer'09
Fall'09
Steinberger et al., unpublished
Shrub understory vs. open areas along the gradient
Relative Interaction Intensity – Seedling density
RII index (S-O/S+O)
0.5
0.4
***
a
0.3
0.2
ab
0.1
bc
c
0
-0.1
-0.2
-0.3
-0.4
Arid
Semiarid
Medit.
-0.5
Sites along the gradient
Mesic. Medit.
Changes in germination strategies along
the aridity gradient
Germination (%)
100
***
aa a
bb b
ab
ab
1st germination year
bb
aaa
80
2nd germination year
3rd germination year
ab
ab
ab
bbb
bb
bb
bbb
aaa
60
bbb
0
Arid
Semiarid
Medit
Site
mesic Medit
Higher
germination
fractions at the
arid extreme of
the gradient
Climate treatment effects on germination
strategies
Mediterranean
100
n.s
1st germination year
2nd germination year
80
Germination (%)
3rd germination year
60
0
40%
Drought
Control
Irrigation
Semiarid
100
n.s
80
60
0
Drought
Control
Treatment
Irrigation
No treatment effect
Mediterranean
100
n.s
1st germination year
2nd germination year
80
Germination (%)
3rd germination year
60
0
40%
Drought
Control
Irrigation
Semiarid
100
n.s
80
60
0
Drought
Control
Treatment
Irrigation
Plant density & species richness
Density Adults (Mediterranean) open
wet
control
dry
rain
Individuals / 400cm² +1SE
200
160
800
120
600
80
400
Mediterranean station:
40
200
Density:
0
Strong temporal fluctuation.
0
2002
2003
2004
2005
2006
2007
2008
Species Number Adults (Medit.) Open
Species / 400cm² +1SE
1000
Wet (and dry) lower than control
20
No treatment effect
16
Richness:
12
Weak temporal fluctuation, No
change by treatment.
8
4
0
2002
2003
2004
2005
2006
2007
2008
Semiarid site similar
pattern!
Metz et al., 2010
Soil respiration & rainfall manipulations
Shrub understory vs. open areas along the
gradient - Species richness
mesic Mediterranean
180 40
Species richness
12
Habitat ***
Year ***
H x Y NS
10
8
160 35
1200
Habitat *
Year ***
H x Y NS
1000
140 30
120
100
6
800
25
20
600
80
4
60
40
2
0
15
400
Rainfall (mm)
Arid
10
20
5
0
0
200
0
2001 2002 2003 2004 2005 2006 2007 2008 2009
2001 2002 2003 2004 2005 2006 2007 2008 2009
Year
shrub
open
rainfall
Habitat differential effect on species
richness between arid vs. mesic Med.
No direct relationship between rainfall and
spp. richness