marcelo sternberg department of molecular biology & ecology of plants
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Climate change in unpredictable terrestrial ecosystems: an integrative approach along an aridity
gradient in Israel
Marcelo SternbergDepartment of Molecular Biology & Ecology of Plants
Tel Aviv University, Israel
GLOWA – Jordan River
GLOWA
Global water cycle
Water cycle: dominant cause of uncertainty in climate change projections
Soil moisture
Water vapor (dew & air humidity
Evapo-transpiration & evaporation
Climate change Land use change+ & -
feedbacks
Green water: terrestrial ecosystems
Precipitation–the basic water resource
GW GW
GW
GW
GW
Falkenmark 2003
GLOWA – Jordan River
Or….Being a prophet in the “Land of Prophets”……
………a tough job
What will happen to natural ecosystems and their “users”?
Alon Angert, Jose Gruenzweig, Jaime Kigel, Irit Konsens The Hebrew University of Jerusalem, Israel
Research partners
Katja Tielboerger Tuebingen University, Germany
Yossi SteinbergerBar-Ilan University, Israel
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
The gradient:
Mesic Mediterranean
Arid Semiarid Mediterranean
Study sites
Rainfall along the aridity gradient
Rainfall (mm)
Source: IMS
Rainfall CV (%) Rainfall predictability along the aridity gradient
Source: IMS
TopographySouth-facing slopes with stony and shallow soil (Terra rossa to desert lithosol on hard limestone and chalk)
TemperatureMean annual temperature 180C-190C
RainfallMainly winter - 5 summer months with no rainfallRange North-South: 780 to 90 mm
~ 24
5 km
Mesic Mediterranean - 780 mm – CV 22%
Mediterranean - 540 mm – CV 30%
Semiarid – 300 mm – CV 37%
Arid – 90 mm – CV 51%
Aridity gradient
Rai
nfal
l (m
m)
0
100
200
300
400
500
600
700
800
Oct-06 Dec-06 Feb-07 Apr-07 Jun-07 Aug-07 Oct-07
Mesic MediterraneanMediterraneanSemiaridArid
795 mm
609 mm
270 mm
Rainfall along the gradient
Date
Differences in length of the growing seasonTalmor et al., 2010 GCB
100 mm
Experimentally testing the effects of climate change
Sprinkler Irrigated Plots (25 x 10 m) – 30% increase
Rainout Shelters (25 x 10 m) – 30% reduction
DroughtSupplemented rainfall
Mediterranean 540 mm
Semiarid 300 mm
Arid 90 mm
Mesic Mediterranean
780 mm N
Experimental design
DroughtSupplemented rainfall
MAT Mediterranean
540 mm
LAH Semiarid
300 mm
SDE Arid
90 mm
EIN - Mesic Mediterranean
780 mm N
Experimental design
Data collection – Gradient vs. manipulation data
Rainfall manipulationsGradient
Vegetation NPP Species richness Species diversity Soil seed banks Seedling mortality Ecosystem
Soil respiration NO3, NH4 & PO4 P (d18Op )
Plant litter decomposition Soil mesofauna Ground insects (beetles)
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
Soil mesofauna Ground insect (beetles)
The gradient:
Mesic Mediterranean
Arid Semiarid Mediterranean
Results
NO3- increased with increasing rainfall – P decreased at the most
mesic site – seasonal changes
Soil nutrients along the gradient
MediterraneanArid Mesic Med.Semiarid
Sep-07 Mar-08 Sep-08 Mar-09 Sep-09 Mar-100
5
10
15
20
25
30
35
P - Control
mg/
kg
Sep-07 Mar-08 Sep-08 Mar-09 Sep-09 Mar-100
20
40
60
80
100
120
140
NO3- - Control
mg/
kg
Time
N and OC increases with increasing rainfall – seasonal changes
Soil nutrients along the gradient
MediterraneanArid Mesic Med.Semiarid
Time
Sep-07 Mar-08 Sep-08 Mar-09 Sep-09 Mar-100
0.1
0.2
0.3
0.4
0.5
0.6
N - Control
%N
Sep-07 Mar-08 Sep-08 Mar-09 Sep-09 Mar-100
0.5
1
1.5
2
2.5
3
3.5
OC - Control
%O
C
Linear relationship between annual rainfall and herbaceous biomass production until 450 mm
Primary productivity along the gradient
Kigel et al., unpublished
0 200 400 600 800 1000 12000
50
100
150
200
250
300
350
Rainfall (mm/yr)
g/m
2
MediterraneanArid Mesic Med.Semiarid
No linear relationship between rainfall & spp. richness at the mesic sites
Species richness along the gradient
Kigel et al., unpublished
0 1 2 3 4 5 6 7 8 9 100
1 0
2 0
3 0
4 0
5 0
6 0
7 0
Species richness (20 x 20 cm)
EJML
SB
EJML
SB
2003 20052002 2006 2007 2008 20092004 2010
MediterraneanArid Mesic Med.Semiarid
Year
Species richness and rainfall along the gradient
Kigel et al., unpublished
MediterraneanArid Mesic Med.Semiarid
0 20 0 4 00 60 0 8 00 10 0 0 1 20 00
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
f( x) = − 0. 000148179 32 4676316 x² + 0. 19726996 131947 x − 5. 1042 88 59825962R² = 0. 92598295 3053302
Rainfall (mm/ yr )
Species richness (20 x 20 cm)
EJ
M
L
SB
Species richness & APP correlation along the gradient
Kigel et al., unpublished
MediterraneanArid Mesic Med.Semiarid
0 2 00 4 00 6 00 80 0 1 00 0 1 20 00
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
f(x ) = − 0. 00 01 4 81 79 32 4 7 x² + 0 .19 7 26 9 96 13 19 4 7 x − 5. 10 4 28 85 9 82 59 6R ² = 0 .9 25 98 29 5 30 5 33 02
Rai nf a ll (mm /y r)
Species richness (20 x 20 cm)
E J
M
L
S B
0 50 10 0 15 0 20 0 25 0 30 0 35 0 40 0 4 50 50 0 5 50 60 0 65 00
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
f(x ) = − 0. 00 0 40 89 5 95 45 9 7 x² + 0 .31 3 22 17 8 53 3 74 5 x + 8 .78 8 72 8 53 75 23 7R ² = 0 .8 32 4 59 78 6 41 5 61 5
Bioma s s DW ( gr/ m2 )
Species richness (20 x 20 cm)
E J
M
L
S B
Soil seed bank
Changes in seed bank density along the aridity gradient
Mediter.
arid
mesic Mediter.
semiarid
Important differences among sites & years
Strong densities variation with rainfall at the mesic sites
Mea
n N
o of
see
dlin
gs (m
-2)
2001 2002 2003 2004 2005 2006 2007 2008 20090
5000
10000
15000
20000
25000
30000Station *** Year *** S x Y ***
Year
Changes in community structure along the aridity gradient
Spe
cies
rich
ness
Spe
cies
eve
nnes
s (J
’)
Year
Mediter.
arid
mesic Mediter.
semiarid
Important differences among
sites .No linear relation between rainfall and spp. richness &
diversity .Decreasing trend of spp. richness at the more mesic sites
2001 2002 2003 2004 2005 2006 2007 2008 20090
10
20
30
40
50Station *** Year *** S x Y ***
2001 2002 2003 2004 2005 2006 2007 2008 20090
0.5
1
1.5
2
2.5
3
3.5
4Station *** Year *** S x Y **
2001 2002 2003 2004 2005 2006 2007 2008 20090
0.10.20.30.40.50.60.70.80.9
1
Station *** Year *** SxY **
Spe
cies
div
ersi
ty (H
’)
Experimentally testing the effects of climate change
Sprinkler Irrigated Plots (25 x 10 m) – 30% increase
Rainout Shelters (25 x 10 m) – 30% reduction
Climate treatment effects on primary productivity
Rainfall manipulations had a significant effect on biomass production at the semiarid station only
Year
Kigel et al., unpublished
2003 2004 2006 2007 2008 2009 20100
50
100
150
200
250
300
350
0
50
100
150
200
250
300
350
Semiarid Drought Control WateringRain
g/m
2
2004
2007
2009
100
150
200
250
300
350
0
100
200
300
400
500
600
700
800
MediterraneanDrought Control WateringRain
g/m
2
Year*** Treatment NST x Y NS
Year*** Treatment**
T x Y NS
Climate treatment effects on primary productivity
Effective rainfall manipulations had a significant effect on biomass production at the semiarid station only
Kigel et al., unpublished
50 100 150 200 250 300 350 400 4500
50
100
150
200
250
R² = 0.748538952757837
R² = 0.525038482266961
R² = 0.794804320498951
SemiaridControl Linear (Control)
Rainfall (mm/yr)
g/m
2
200 300 400 500 600 700 800 900 1000 1100100
150
200
250
300
350
Mediterranean
Control Drought Watering
Rainfall (mm/yr)
g/m
2
2003 2004 2005 2006 2007 2008 20090
5000
10000
15000
20000
25000
0
100
200
300
400
500
600
700
800
900
Effects of rainfall manipulations on seed bank density
watering
drought
rainfall
control
Rai
nfal
l (m
m)
2003 2004 2005 2006 2007 2008 20090
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
0
50
100
150
200
250
300
350
400
450
Year
Treat. NS Year *** T x Y NS
Semiarid Mediterranean
Mea
n N
o of
see
dlin
gs (m
-2) Treat. NS
Year *** T x Y NS
2003 2004 2005 2006 2007 2008 20090
5000
10000
15000
20000
25000
0
100
200
300
400
500
600
700
800
900
watering
drought
rainfall
control
Rai
nfal
l (m
m)
2003 2004 2005 2006 2007 2008 20090
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
0
50
100
150
200
250
300
350
400
450
Year
Treat. NS Year *** T x Y NS
Semiarid Mediterranean
Mea
n N
o of
see
dlin
gs (m
-2) Treat. NS
Year *** T x Y NS
No treatment effect on seed bank density
Effects of rainfall manipulations on community structure – Mediterranean site
watering
drought
rainfall
control
2003 2004 2005 2006 2007 2008 20090
5
10
15
20
25
30
35
40
0
100
200
300
400
500
600
700
800
900
Spe
cies
rich
ness
2003 2004 2005 2006 2007 2008 20090
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0
100
200
300
400
500
600
700
800
900
Spe
cies
div
ersi
ty (H
’)
Treat. NS Year *** T x Y NS
Treat. NS Year *** T x Y NS
Rai
nfal
l (m
m)
Year
watering
drought
rainfall
control
2003 2004 2005 2006 2007 2008 20090
5
10
15
20
25
30
35
40
0
100
200
300
400
500
600
700
800
900
Spe
cies
rich
ness
2003 2004 2005 2006 2007 2008 20090
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0
100
200
300
400
500
600
700
800
900
Spe
cies
div
ersi
ty (H
’)
Treat. NS Year *** T x Y NS
Treat. NS Year *** T x Y NS
Rai
nfal
l (m
m)
Year
No rainfall manipulations effects on community structure – Mediterranean site
Similar results at the semiarid site
Effects of rainfall manipulations on insect density
Shtirberg et al., unpublished
Effects of rainfall manipulations on insect density
Shtirberg et al., unpublished
0
200
400
600
800
1000
1200
1400
Drought Control Watering
Treatment
MediterraneanSemiarid
Mea
n N
o of
inse
cts
0
200
400
600
800
1000
1200
1400
Drought Control Watering
Treatment
‘07‘06 ‘07‘06‘07‘06‘07‘06 ‘07‘06‘07‘06
Treat. NS Year *** T x Y NS
Treat. NS Year *** T x Y NS
Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07
Volu
met
ric S
WC
(%)
Rainfall (m
m)
R s (µ
mol
CO 2
m-2 s-
1 )
0
5
10
15
20
25
30
35
40
45
DryControlWet
0
10
20
30
40
50
60
70
80MediterraneanOpen
0
2
4
6
8
10
90
Rainfall, soil moisture & soil respiration
Talmor et al., 2011
GCB
0
200
400
600
800
1000
Open Shrub Open Shrub
Mediterranean Semiarid
WetControlDry
p<0.05
A
AB
B
R s (g
C m
-2 y
-1)
Soil respiration & rainfall manipulations
Talmor et al., 2010
Effects of rainfall manipulations on soil microbial biomass
MediterraneanSemiarid
Mic
robi
al b
iom
ass
(µg
C g
soi
l-1)
2008‘ & 09 Seasons & Treatments
Sherman et al., unpublished
Season – significant changes No consistent pattern of treatment response
20082009
Winter Spring SummerAutumn
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 short-term 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
Conclusions
Eastern Mediterranean ecosystems have evolved under high climatic variability conditions, high levels of stress and perturbations – Ecosystems characterized by high spatial & temporal variabilityDoes 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
ᵦ species diversity – changes is composition similarity between stations and years
Arid ‘02 Semiarid ‘02 Medit. ’02 M. Med ‘02 Arid ‘07 Semiarid ‘07 Med. ‘07 M. Med ‘07
Arid ‘02 -
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 -
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
Soil fungi species richness along the gradient
Steinberger et al., unpublished
MediterraneanArid Mesic Med.Semiarid
Winter'08 Spring'08 Summer'08
Fall'08 Winter'09 Spring'09 Summer'09
Fall'09 0
10
20
30
40
Soil
fung
i spe
cies
rich
ness
(gr)
RII
inde
x (S
-O/S
+O)
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
Mesic. Medit.Medit.SemiaridArid
a
ab
bcc
Shrub understory vs. open areas along the gradient Relative Interaction Intensity – Seedling density
***
Sites along the gradient
Ger
min
atio
n(%
) Changes in germination strategies along
the aridity gradient
2nd germination year
3rd germination year
1st germination year
0
bbb
a
a
ab b b
bb
ab
a100
mesic MeditMeditSemiaridArid
bbb
a
a
ab bb
bbab
a
80
bbb
a
a
ab b b
bb
ab
a***
Site
bbb
a
a
ab bb
bbab
a
60
Higher germination
fractions at the arid extreme of
the gradient
G
erm
inat
ion
(%)
Treatment
40%
60
80
100
Drought Control Irrigation
n.s
60
80
100
Drought Control Irrigation
n.s
0
0
Climate treatment effects on germination strategies
Semiarid
Mediterranean
2nd germination year
3rd germination year
1st germination year
G
erm
inat
ion
(%)
Treatment
40%
60
80
100
Drought Control Irrigation
n.s
60
80
100
Drought Control Irrigation
n.s
0
0
No treatment effect
Semiarid
Mediterranean
2nd germination year
3rd germination year
1st germination year
Plant density & species richness
Density Adults (Mediterranean) open
0
40
80
120
160
200
2002 2003 2004 2005 2006 2007 2008
Indi
vidu
als
/ 400
cm² +
1SE
0
200
400
600
800
1000wetcontroldryrain
Species Number Adults (Medit.) Open
0
4
8
12
16
20
2002 2003 2004 2005 2006 2007 2008
Spe
cies
/ 40
0cm
² +1S
E
Mediterranean station:Density:Strong temporal fluctuation.
Wet (and dry) lower than control
No treatment effectRichness:Weak temporal fluctuation, No change by treatment.
Semiarid site similar pattern!
Metz et al., 2010
Soil respiration & rainfall manipulations
Shrub understory vs. open areas along the gradient - Species richness
shrub
rainfallopen
Spe
cies
rich
ness
mesic MediterraneanArid
Habitat differential effect on species richness between arid vs. mesic Med.
No direct relationship between rainfall and spp. richness
2001 2002 2003 2004 2005 2006 2007 2008 20090
5
10
15
20
25
30
35
0
200
400
600
800
1000
1200Habitat * Year *** H x Y NS
2001 2002 2003 2004 2005 2006 2007 2008 20090
2
4
6
8
10
12
0
20
40
60
80
100
120
140
160
180
Habitat *** Year *** H x Y NS
Year
Rai
nfal
l (m
m)