Evaluating wildfire-mediated vegetation change and climate-change refugia potential across Alberta boreal forests

Diana Stralberg1, Xianli Wang1,2, Marc-André Parisien2, François-Nicolas Robinne1, C. Lisa Mahon3, Péter Sólymos1,4, Scott E. Nilesen1, Erin M. Bayne1,4

1 University of Alberta, 2 Natural Resources Canada, 3 Environment and Climate Change Canada, 4 Alberta Biodiversity Monitoring Institute

2

Envelope models suggest near disappearance of climates suitable for Alberta’s boreal forests

3Rooney et al. 2015 (Science)(adapted from Schneider 2013) Stralberg et al. 2015 (Ecol. Appl.)

CanadaWarbler

Olive-sided Flycatcher

Cape May Warbler

TEW

ACO

NW

GRA

JLI

SPBB

WA

RCKI

CMW

AW

WCR

YRW

APA

WA

SWTH

DEJU PISI

PHVI

BOCH

WTS

PW

IWA

WET

AHE

THAL

FLFO

SPO

CWA

WCS

PN

OW

AVA

THCC

SPLC

SPRU

BLYB

FLBL

PW OSF

LBH

VIM

AWA

LEFL

GCK

IW

IWR

OVE

NM

OW

API

GR

BRCR

CAW

ACH

SPRB

NU

AMRE

CORA

WEW

PBT

NW

WAV

IRE

VIRB

GR

SWSP

VESP

YWAR

EVG

RBA

WW

PUFI

SAVS

AMCR

HOLA

BRBL

AMRO

CEDW

BLBW

BCCH

TRES

COYE

SOSP

CSW

AEA

PHBL

JABH

CORW

BLAM

GO

-150%

-50%

50%

150%

250%

350%

450%

4

Suitable habitat for majority of Alberta boreal bird species projected to decline by 2100

5 unequivocal increasers

32 unequivocal decreasers

Stralberg et al. 2015 (Ecol. Appl.)

Forest transitions may not occur without disturbance

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© B. de Groot, Coffee fire, Saskatchewan, 1980

Topography, geology, and soils will constrain change

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© Sara Venskaitis, ABMI © Janet Ng© Michel Rapinski, ABMI

From Ecosites of Northern Alberta,Beckingham & Archibald 1996

nutrient medium-rich

nutrient poor

Research questions• What are realistic rates and spatial patterns of future

vegetation change in northern Alberta, considering disturbance and physical constraints?

• What is the difference between climate-driven and “fire-mediated” vegetation change potential

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Photos © Natural Resources Canada

PredictedVegetation Type

ABMI monitoring data used to develop vegetation models

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6 climate variables

6 terrain variables + geology+ mappedwetlands

n = 10,080

PredictedVegetation Type

ABMI monitoring data used to develop vegetation models

9

6 climate variables

6 terrain variables + geology+ mappedwetlands

Random forest model62% cross-validation accuracy (89% for medium-mesic)

PredictedEcosite Type

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500-m pixel resolution

PredictedVegetation Type

ABMI monitoring data used to develop vegetation models

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*

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*

* upland

Random forest model81% cross-validation accuracy

Climate-driven vegetation change, constrained by physical site conditions

11CSIROGlobal Climate Model RCP 8.5 (high emissions)

* Upland vegetation projected

Lowland vegetation held constant

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*

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*

B1 A1A2 B2Potential

Vegetation

ActualVegetation B1 A1

A2 B2

Climate-driven

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B AA B

B2 A2A2 B2

B2 A3A3 B2

B AA BEcosite

B1 A2A2 B2

B2 A2A3 B2

B AA B

Fire-mediated vegetation changeTime 1 Time 2 Time 3

Topoedaphic

Fire-mediated

B1 A1A2 B2

B1 A1A2 B2

B1 A1A2 B2Replicate 2

.

.

Burn-P3Fire simulation model (Parisien et al. 2005)

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Fire-mediated

vegetation (constrainedfire regime)

ProportionalChange in cover

type over multiple fuel

iterations, Burn-P3 runs and

GCMs (RCP 8.5)

Conifer

Mixedwood

Deciduous

Grassland

Baseline 2011-2040 2041-2070 2071-2100

Stralberg et al. 2018 (Ecosphere)

Climate-driven vs. fire-mediated vegetation scenarios

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RCP 8.5, multiple GCMs

Conservation and Management Applications

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Summary and next steps• Even under the current fire regime, fire is

likely to catalyze rapid vegetation change• Potential for much more dramatic

vegetation change with more frequent and larger fires (knowledge gap)

• Next step is finer-scale identification of:• Fire refugia (e.g., lakeshores and

islands)• Topographic refugia (e.g. north slopes

and valley bottoms)• Vegetation resilience (e.g., peatlands)

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NNorth-facing slope

Adiabatic cooling

Peatland moistureretention

(Thompson et al. 2013, Waddington et al. 2015, Schneider et al. 2016)

Lake breezes

Fire refugia

Stralberg et al. in prep.

(Parisien et al. 2003, Fisichelli et al. 2012, Nielsen et al. 2016)

(Ashcroft et al. 2009, Dobrowski 2010)

Thank you!Co-authors: Xianli Wang, Marc Parisien, François Robinne, Lisa Mahon, Scott Nielsen, Erin Bayne

Data and other contributions: Craig Aumann, Nicole Barker, Matt Carlson, Steve Cumming, QiongYan Fang, Dan Farr, Trish Fontaine, Tom Habib, Suzanne Lavoie, Scott Nielsen, Amy Nixon, Daiyuan Pan, Jim Schieck, Fiona Schmiegelow, Rick Schneider, Brian Simpson, Samantha Song, Jessica Stolar, Mike Willoughby

Funding and support:

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