1

Philip Higueraphiguera@uidaho.edu

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

66

|------- 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

11

↓ 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)

13

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

16

#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

18

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

21

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

22

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

24

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

27

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

Questions?

Philip Higueraphiguera@uidaho.edu