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Resilience and sensitivity of
high-severity fire regimes to climatic
variability from centuries to millennia
)P
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Philip Higuera1*
Ryan Kelly2
Feng Sheng Hu2
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AGU13 - GC24A-01
(c
Univ. of Idaho1, Univ. of Illinois3
*@PhilipHiguera, phiguera@uidaho.edu
P. Higuera, 2006
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Climate Change and Wildfires
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(c
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Climate Change and Wildfires
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Climate
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Moisture avail.
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Drivers and Interactions
Fire Regime
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Vegetation
Biome, stand level
Stand-replacing
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Climate
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Moisture avail.
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Consequences
Fire Regime
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Vegetation
Biome, stand level
Stand-replacing
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1. Reconstructing the past
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fo
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When do we see changing
fire regimes in the past?
ra
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2. Examples of sensitivity and resilience; inferred
mechanisms
(c
)P
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“…ability of [a] system to absorb changes
of…driving variables…and still persist.”
Holling (1973)
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Reconstructing the past
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charcoal:
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macrofossils:
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pollen:
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Fire history from continuous sediment records
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Theoretical /
modeling:
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(c
Empirical
tests:
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Higuera et al. 2007, 2013
Peters and Higuera, 2007
Kelly, et al., 2011.
Kelly et al. 2013 PNAS
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Lessons from PaleoEcology
fo
When do we see changing fire regimes in the past?
Climate
co
nt
ac
t
1. …when climate change directly
influences fuel moisture
Fire
as
e
Regime
Climate
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)P
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ra
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2. …when millennial-scale climate
change results in vegetation
shifts that change flammability
Veg.
Fire
Regime
fo
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1. Increased burning with post-glacial warming
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as
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Biomass
burning
(c
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*Sensitivity at
multi-millennial
time scales
Charcoal accumulation
(z-score)
co
nt
ac
t
Temperature
proxy
Years before present (x 1000)
Daniau et al. 2012, Global Biogeochemical Cycles – Global Paleofire Working Group: gpwg.org
ra
Generalized additive model
Temp. explains ≈ 56% of var.
(c
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ue
Climate
+
+
Fire
Veg.
Regime
-p
Charcoal accumulation
le
(z-score)
as
e
co
nt
ac
t
fo
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se
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1. Increased burning with post-glacial warming
Mean annual temperature
(z-score)
Daniau et al. 2012, Global Biogeochemical Cycles
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Boreal Forest
(c
)P
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Forest-tundra
as
e
co
nt
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fo
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se
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2. Increased burning with boreal forest development
Higuera et al. 2009, Ecological Monographs
Brubaker et al. 2009, Ecology
Years before present
ru
se
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2. Increased burning with boreal forest development
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(c
FRI (yr)
ra
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as
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CHAR
(# cm-2 yr-1)
co
nt
ac
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fo
*Sensitivity at multi-millennial time scales
Higuera et al. 2009, Ecological Monographs
Brubaker et al. 2009, Ecology
Years before present
2. Increased burning with boreal forest development
*Vegetation
mediated impacts
of climatic change
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ue
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(c
FRI (yr)
ra
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as
e
CHAR
(# cm-2 yr-1)
co
nt
ac
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fo
ru
se
.
Climate
+
Fire
Veg.
Regime
Higuera et al. 2009, Ecological Monographs
Brubaker et al. 2009, Ecology
Years before present
2. Increased burning with boreal forest development
ig
ue
)P
.H
(c
FRI (yr)
ra
-p
le
as
e
CHAR
(# cm-2 yr-1)
co
nt
ac
t
fo
ru
se
.
*Relatively stable mean fire return
intervals, at 2000-yr scale
Higuera et al. 2009, Ecological Monographs
Brubaker et al. 2009, Ecology
Years before present
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3. Sensitivity to centennial-scale climate variability
Kelly et al. 2013, PNAS
3. Sensitivity to centennial-scale climate variability
ru
se
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CHAR : FF
(fire severity)
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MCA
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*Fire frequency
non-varying
(c
[except recent decades]
Kelly et al. 2013, PNAS
FF
Years before present
LIA
Fire frequency (# / 1000 yr)
*Biomass burned
sensitive to climate
variability
as
e
CHAR
co
nt
ac
t
fo
*Increased fire
severity during
MCA
3. Fire-vegetation-fire feedbacks
*Increased
deciduous species
limited fire
frequency
fo
ru
se
.
P. mariana
-p
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ig
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)P
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(c
Johnstone et al. (2010)
Kelly et al. 2013, PNAS
FF
Years before present
Fire frequency (# / 1000 yr)
as
e
CHAR
co
nt
ac
t
Populus
Proximal
Mechanism
nt
Climate
co
Altered fuel moisture
e
Fire
-p
le
as
Regime
Centuries to
millennia
(c
Climate
)P
.H
Regime
Successional
vegetation shifts
Years to
centuries
Veg.
ig
ue
Fire
Fire
Regime
Years to
decades
Biome-scale
vegetation shifts
ra
Climate
Veg.
Time
Scale
ac
t
fo
Pathway
ru
se
.
Mechanisms for climate impacts on fire regimes
ac
t
nt
-p
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as
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co
1. Paleo records illustrate both
resilience and sensitivity to
climate change
fo
Lessons from PaleoEcology
)P
.H
ig
ue
ra
2. Direct climate impacts from
centennial through millennial
scales
3. Vegetation-mediated impacts
from decadal through millennial
scales, including feedbacks
(c
ru
se
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Summary
Questions?
ac
t
nt
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as
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co
1. Paleo records illustrate both
resilience and sensitivity to
climate change
fo
Lessons from PaleoEcology
)P
.H
ig
ue
ra
2. Direct climate impacts from
centennial through millennial
scales
3. Vegetation-mediated impacts
from decadal through millennial
scales, including feedbacks
(c
ru
se
.
Philip Higuera, University of Idaho
@PhilipHiguera, phiguera@uidaho.edu