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Global Change Research from the Ground Up
1000 1100 1200 14001300 16001500 18001700 1900 2000 2100
1
0
4
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-1
Mean global temperature anomalies: last 1000 yrs
indirect measuresdirect
measures
projections
IPCC (2001)
Projected changes in average annual water runoff by 2050, relative to average runoff for 1961-1990
IPCC (2001)
IPCC (2001)
Millennium Ecosystem Assessment (2005)
Atmosphericnitrogen deposition
global environmental change
elevated CO2 warming precipitation nitrogen
Percentage change in average annual total Australian wheat yield for CO2 (levels of 700 ppm)
IPCC (2001)
rainfall change
global environmental change
elevated CO2 warming precipitation nitrogen
global environmental change
elevated CO2 warming precipitation nitrogen
additive effects?
Jasper Ridge Global Change Experiment(1998-present)
Jasper Ridge, California Toronto, Ontario
dai
ly t
emp
erat
ure
(o
C)
-20
-10
0
10
20
30
jan
feb
mar ap
rm
ay jun ju
lau
gse
poct
novdec
mo
nth
ly p
reci
pit
atio
n (
mm
)
0
20
40
60
80
100-20
-10
0
10
20
30
maxmin
jan
feb
mar ap
rm
ay jun ju
lau
gse
poct
novdec
0
20
40
60
80
100
dai
ly t
emp
erat
ure
(o
C)
mo
nth
ly p
reci
pit
atio
n (
mm
)
dai
ly t
emp
erat
ure
(o
C)
-20
-10
0
10
20
30
jan
feb
mar ap
rm
ay jun ju
lau
gse
poct
novdec
mo
nth
ly p
reci
pit
atio
n (
mm
)
0
20
40
60
80
100-20
-10
0
10
20
30
maxmin
jan
feb
mar ap
rm
ay jun ju
lau
gse
poct
novdec
0
20
40
60
80
100
dai
ly t
emp
erat
ure
(o
C)
mo
nth
ly p
reci
pit
atio
n (
mm
)
Jasper Ridge, California Toronto, Ontario
Native perennial grasses (Danthonia californica and Nassella pulchra)
Non-native annual grasses (Avena barbata, A. fatua, Bromus hordeaceus and Lolium multiflorum)
Non-native forbs (Geranium dissectum, Erodium botrys and Crepis vesicaria)
Native annual forbs (Hemizonia congesta and Epilobium brachycarpum)
Annual grassland
The annual grassland as a model system
1. Small individuals = community level treatmentsin a small area
2. Annual lifecycle = treatments over multiple generations
3. Established plant and soil microbial communities
20 cm
Year 1 Year 2 Year 3 Year 4
Jasper Ridge Global Change Experiment(1998-present)
CO2 - free air emitters: ~ 680 ppm
open top chamber for CO2 delivery
Jasper Ridge Global Change Experiment(1998-present)
NO3- - application: 7 g N m-2 y-1
Jasper Ridge Global Change Experiment(1998-present)
heat - infrared lamps: 1-2 °C
Jasper Ridge Global Change Experiment(1998-present)
H2O - irrigation: ambient + 50%
NO3- H2Oheatcontrol
heatNO3
-
heatH2O
NO3-
H2O
NO3-
heatH2O
0
20
40
60
80
100
120
per
cen
t ch
ang
e in
NP
P
ambient CO2
NO3- H2Oheatcontrol heat
NO3-
heatH2O
NO3-
H2ONO3
-
heatH2O
(Shaw et al. 2002)
NO3- H2Oheatcontrol
heatNO3
-
heatH2O
NO3-
H2O
NO3-
heatH2O
0
20
40
60
80
100
120
per
cen
t ch
ang
e in
NP
P
ambient CO2
680 ppm CO2
NO3- H2Oheat heat
NO3-
heatH2O
NO3-
H2ONO3
-
heatH2O
(Shaw et al. 2002)
0
20
40
60
80
100
120
per
cen
t ch
ang
e in
NP
P
ambient CO2
680 ppm CO2
NO3- H2Oheat heat
NO3-
heatH2O
NO3-
H2ONO3
-
heatH2O
(Shaw et al. 2002)
Dukes et al. (2005)
Dukes et al. (2005)
Fire!July 2003
Net primary production
NO3- added
NP
P (
g d
w m
-2)
0
200
400
600
800
1000
1200
1400
1600
1800unburned burned
NO3- added
ambient CO2
elevated CO2
NNN
N
Col 1
NO3- added
an
nu
al g
ras
s s
ho
ots
(g
dw
m-2)
0
200
400
600
800unburned burned
NO3- added
ambient CO2
elevated CO2
Annual grasses
NN
N N
NO3- ***
B *NO3
- X CO2 **
Herbivore effects
Slug feeding preferences and abundance in plots explain over 50% of variation in productivity
Lessons learned from the JRGCE:
1. Global change will result in changes in ecosystemproductivity and plant species composition
2. Unforeseen interactions of climate change withnitrogen pollution and elevated CO2
Wildcards: influence of disturbance and herbivores
Davis (1981)
Invasive species
My current research:Winter warming and N deposition
tem
per
atu
re (
°C)
-30
-20
-10
0
10
20
30
air
Nov Dec Jan Feb Mar
Agricultural field near London, ON
tem
per
atu
re (
°C)
-30
-20
-10
0
10
20
30
air soil surface
Nov Dec Jan Feb Mar
continuous snow cover
Agricultural field near London, ON
Effects of freezing on soil
soil aggregatedisruption
microbial lysis
plant litter breakdown
root lysis
leaching losses of C, N and P
CO2, N2O
Effects of freeze-thaw
soil aggregatedisruption
microbial lysis
plant litter breakdown
root lysis
Long-term warming and N deposition experiment
Long-term warming and N deposition experiment
Objective:
To explore the interactive effects of climate warming and increased atmospheric N deposition on a temperate ecosystem
- specific emphasis on winter warming
Grasses:Poa pratensis (Kentucky blue grass) – perennial Bromus inermis (smooth brome) – perennial
Forbs:Solidago altissima (tall goldenrod) – perennial Cirsium arvense (Canada thistle) – perennial
Medicago lupulina (black medick) – annual/perennial, legumeMelilotus alba (white sweet-clover) – annual/perennial, legumeLotus corniculatus (bird’s foot trefoil) – perennial, legume
110 V AC soilsurface
150 Wceramic infraredheater
reflector
weatherprooflightbulb socket
metal pipe
Heating bracket (heats 3 plots)
Side view:
height-adjustablebracket
1 m
Block design
1 plot
= dummy heater
= IR heater(n=10)
1 m
1 plot
= dummy heater
= IR heater
heated-all year
heated-late-fall
to spring
1 m
1 plot
= dummy heater
= IR heater
heated-all year
heated-late-fall
to springN
N
N
Soil monitoring
- soil temperature- 2 and 5 cm depth- hourly
- volumetric water content- 0-15 and 0-30 cm depth- hourly
Te
mp
era
ture
(ºC
)
-5
0
5
10
15
20
25
30
35
Nov Jan Mar May Jul Sep Nov Jan Mar May
Tre
atm
en
t -
am
bie
nt
(ºC
)
-2
-1
0
1
2
3
4
5
2006 2007 2008
winter warmedwarmed
- PTFE/quartz lysimeters- no retention/contamination- durable- 50 cm depth
Soil water collection
Terry BellSoil microbial enzyme activities
and microbial community structure
Jennifer HutchisonPrimary production and
plant species composition
Paul Mensink and Eric MoiseInvasive wood snails
Michelle TurnerNitrogen leaching losses
and net mineralization
Gra
ss d
ry m
as
s (
g m
-2)
0
200
400
600
800
1000
1200
1400
ambie
nt
win
ter w
arm
ed
war
med
ambie
nt
win
ter w
arm
ed
war
med
N
NN
Cirsium
Lotus
NDVI - Plant Greenness
0 20 40 60
ND
VI
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
ambientwinter warmedwarmed
April 3 June 110 20 40 60
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
ambientnitrogen
April 3 June 11
Net Ecosystem Exchange