interactions of climate, vegetation, and fire during the holocene ... · philip higuera...
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Philip [email protected]
Interactions of climate, vegetation, and fire during the Holocene: insights to future change
“As a result of climate change, we are in essence conducting a global experiment such that future wildland fire activity is highly uncertain.” – Flannigan et al. 2009
Yukon Flats, Alaska
Fire and Climate Change
Modified from Moritz et al. 2005, PNAS
Seconds
VEGETATION
fuel
fuel
Days Decades
Global
Regional
Wildfire
Microsite
MillenniaTIME
SPA
CE
Fire Regime
Fire Behavior
Flame
Conceptual Framework
2468101214-50
-45
-40
-35
-30
Years before present (x 1000)
tem
p. ( °
C)
|----- Holocene ------|
Conceptual Framework
VEGETATION
Fire Regime
Overview
1. Climate-vegetation-fire interactionsReconstructing fire history Insights from AlaskaContext for ongoing change
2. Conceptual challengesDefining regimes and detecting change
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|------- 1 cm -------|
charcoal:
|---- 1 cm ----|
macrofossils:
pollen:
Reconstructing the past
Higuera et al. 2007; Peters and Higuera, 2007
Fire history from continuous sediment records
Year AD
CH
AR
(# c
m-2
yr-1)
% o
f sta
nd
Empiricalsupport:
Theoreticalsupport:
Higuera et al. 2005
Stand age &fire scars
Charcoal accumulation
Years before present (x 1000)
CH
AR
(# c
m-2
yr-1)
1. Raw CHAR 2. “Background”
3. Residual CHAR (background removed)
4. Threshold5. Peaks
Fire history from continuous sediment records
8
Climate Change and Fire RegimesVegetation mediates the impacts of climate change on fire regimes
vs.
Picea
Betula
Alnus
SalixPopulus
ArtemisiaCyperaceae
Poaceae
Veg. Zone14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Years before present (x 1000)
%
HT Shrub Tundra DW Forest-tundra Boreal Forest
Vegetation: Higuera et al. 2009, Ecological Monographs
No-analog
Climate: Anderson and Brubaker, 1993,1994.
Climate Change
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↓ FIRE ? FIRE ↓ FIRE ↓ FIRE ↑ FIRE
↓ FIRE ↑ FIRE ↓ FIRE
Hveg
Years before present (x 1000)02468101214
Hclimate
Climate Change
HerbTundra
Shrub Tundra
Deciduous
WoodlandForest-tundra
BorealForest
Vegetation Change
Higuera et al. 2009, Ecological Monographs 12
↓ FIRE ? FIRE ↓ FIRE ↓ FIRE ↑ FIRE
CH
AR
(# c
m-2
yr-1) ↓ ↑ FIRE ↓ FIRE ↓ FIRE ↑ FIRE
↓ FIRE ↑ FIRE ↓ FIREHclimate
Hveg
Higuera et al. 2009, Ecological Monographs
Years before present (x 1000)
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Higuera et al., 2008, PLoS ONE; Higuera et al. 2009 Ecological Monographs; Tinner et al. 2008.
prop
ortio
n O
Rde
nsity
(x20
)
Herb Tundra Shrub Tundra
-
0.2-
-
0.0 -
144 (120-169)
N = 45N = 1
- - - - -
fire return interval (yr)
0- -40
0- -80
0-
+ +
14
Higuera et al. 2009 Ecological Monographs
prop
ortio
n O
Rde
nsity
(x20
)
Shrub Tundra Decid. Wood.
0- -40
0- -80
0-
-
0.2-
-
0.0 -
144 (120-169)
N = 45
- - - - -
fire return interval (yr)
0- -40
0- -80
0-
251 (156-347)
N = 11
+ -
15
Higuera et al. 2009 Ecological Monographs; Also: Lynch et al. 2002
prop
ortio
n O
Rde
nsity
(x20
)
Forest-tundra Boreal Forest
0- -40
0- -80
0-
-
0.2-
-
0.0 -
- - - - -
fire return interval (yr)
0- -40
0- -80
0-- +
227 (170-287)
N = 21145 (130-163)
N = 110
Forest-tundra
Boreal Forest
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#SRuppert
#SRuppert
DeciduousWhite Spruce
Black SpruceTundra
DeciduousWhite Spruce
Black SpruceTundra
ALFRESCO Landscape
100 km
100
km
fire = f(climate, vegetation)
e.g. Rupp, T. S. et al. 2000. Landscape Ecology Brubaker, Higuera, Rupp, Olson, Anderson, and Hu. 2009. Ecology
Modeling climate-veg.-fire interactions:
Brubaker, Higuera, Rupp, Olson, Anderson, and Hu. 2009. Ecology
clim
ate
veg.
& fi
re
Forest-tundra Boreal Forest
Simulated years before present
Veg. and climate change required for data-model match
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As in the past, future fire regimes determined by:
&
If fire is limited more by the abundance and/or continuity of fuels, then vegetation change can be more important than climate change.
19
Western Brooks Range, Alaskan tundra
20
Locally-mediated response to climate change
Raven Lake
Tundra burns
Little Isac
Poktovik
Uchugrak
CH
AR
(# c
m-2
yr-1
)
age (cal. yr BP)
Raven
Records appropriate for peak identification
Recent large fires detected
1984fire
1977fire
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Little IsacRaven
Picea
age (cal. yr BP x 1000)
Betula
Alnus
Cyperaceae
Poaceae
Fire frequency(fires 100-yr-1)
Site-specific patterns
Coherent pattern
% p
olle
n
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time (cal. yr BP)
2000
-yr f
ire fr
eque
ncy
(fir
es 1
00 y
r-1)
Square root-transformed pollen percentage
Picear = 0.83
Poaceaer = 0.50
Betular = 0.55
Poaceaer = 0.70
r2adj = 0.68r2
adj = 0.836 5 4 3 2 1 0 6 5 4 3 2 1 0
Little IsacRaven
23
Context for ongoing change
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Unprecedented Tundra Burning During Extreme Sea-Ice Retreat
F. S. Hu, P.E. Higuera,J. E. Walsh, W. L. Chapman, L. B. Brubaker, M. L. Chipman
Photo: Dale Woitas, AFS, BLMHu, Higuera, et al., In prep.
Overview
1. Climate-vegetation-fire interactionsReconstructing fire history Insights from AlaskaContext for ongoing change
2. Conceptual challengesDefining regimes and detecting change
010002000300040005000600070000
100200300400500
Years before present
Temporal scale of fire regimes
temporal window
(yr)
fire frequency (fires 100 yr -1)
Years before present
FRI (
yr)
CH
AR
(# c
m-2
yr-1
) Boreal ForestForest-tundra
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Temporal scale of fire regimes
28Modified from Whitlock, Higuera, et al. 2010; The Open Ecology Journal
Seconds Days Decades
Global
Regional
Wildfire
Microsite
MillenniaTIME
SPA
CE
AcknowledgmentsFunding:
Field and Lab Assistance:
Collaborators:Jennifer Allen, NPSPat Anderson, U of WATom Brown, LLNLLinda Brubaker, U of WAMelissa Chipman, U of ILFeng Sheng Hu, U of ILScott Rupp, U of AKMike Urban, U of IL
Claire AdamChristy BrilesMelissa ChipmanBen Clegg
Jennifer Leach Amy LilienthalJohn MauroNPS personnel
Kate ShickJason SmithEmily Spaulding
National ScienceFoundation
