tree regeneration vulnerability to climate change ... · belledonne cerces field experiment...

Georges Kunstler, Emmanuel Defossez, Benoît Courbaud

Tree regeneration vulnerability to climate change:relative contribution of direct climate effect, plant interactions, herbivores & pathogens

Tackling climate change : the contribution of forest scientific knowledge. Tours 21 May 2012

Mountain Forests & climatic gradients

500 m 500 m

1000 m1000 m

2000 m2000 m

Quercus

FagusFagus QuercusQuercus

Fagus-Abies-Picea

Picea

PinusPinusClimate Change

Regeneration ?

Elevation range

Tree regeneration

Regeneration (Grubb 1977)

High vulnerability of seedlings

Seedling

ClimateT°/ precipitation

Direct & indirect climate effects on tree regeneration

Seedling

Adult tree

Insects herbivory

Soil µ-organismes


Ground vegetation


Seedling

Adult tree

Insects herbivory

Soil µ-organismes


Ground vegetation


?

?

?

Field experiment

Spatio-temporal variation of climatic conditionsSpatio-temporal variation of climatic conditions- 10 sites- 10 sites- 3 years- 3 years

500 m 500 m

1000 m1000 m

2000 m2000 m

QuercusQuercus

FagusFagus - - QuercusQuercus

Fagus-Abies-Fagus-Abies-PiceaPicea

PiceaPicea

PinusPinus

800 800 mm

1400 m1400 m

2000 m2000 m


FagusFagus - - AbiesAbies

Fagus-Abies-PiceaFagus-Abies-Picea PiceaPicea

Pinus uncinata Pinus uncinata

1500 m1500 m

2000 m2000 m

Pinus sylvestris Pinus sylvestris

Larix decidua Larix decidua


Vercors

Belledonne

Cerces

Field experiment

Spatio-temporal variation of climatic conditionsSpatio-temporal variation of climatic conditions- 10 sites- 10 sites- 3 years- 3 years

Ground vegetation

Can

op

y o

pen

ess g

rad

ien

t

~ 13 000 seedlings

~ 160 000 seeds

Ele

vati

on

8 species : Quercus petraea, Fagus sylvatica, Abies alba, Picea abies, Larix deciduas, Pinus sylvestris, Pinus uncinata & Pinus cembro

Field experiment

NoGround

vegetation

x2

Monitoring of T° & soil water availability on each site

Bioclimatic variables

- Water availability- Water availability- Degree-day sum (>5.54 °C)- Degree-day sum (>5.54 °C)

Correlation => complex climatic Correlation => complex climatic gradientgradient

Seedling survival

Complex plants interactions

ClimateT°/ precipitation Individual based HB regression :

plants interactions coefficients - direct adult tree effect - direct ground vegetation effect - indirect adult tree effect

Coeff

icie

nts

+Facilitation

- Competition

Degree days sum

Direct ground vegetation

Direct adult tree

Indirect adult tree

Results

Low elevation species

High elevation species

Coeff

icie

nts

Direct effect

DDS

Degree days sum

Competition


Direct adult tree

Indirect adult tree

Results

Coeff

icie

nts

Indirect effect

Low elevation Species

Degree days sum

Indirect facilitation


Direct adult tree

Indirect adult tree

Results

High elevation Species

Few indirect effect

500 m 500 m

1000 m1000 m

2000 m2000 m

QuercusQuercus



PiceaPicea

PinusPinus

800 800 mm

1400 m1400 m

2000 m2000 m


FagusFagus - - AbiesAbies

Fagus-Abies-PiceaFagus-Abies-Picea PiceaPicea


1500 m1500 m

2000 m2000 m

Pinus sylvestris Pinus sylvestris Larix decidua Larix decidua


Vercors

Belledonne

Cerces

Insect herbivory field experiment

Leaf herbivory at vegetation peak Leaf herbivory at vegetation peak

% leaf area% leaf area

Degree-day sum

Fagus

Abies

P. uncinata

LarixPicea

P. cembro

Leaf folivory increase with DDS

% f

olivory

Quercus

Lower folivory for high elevation species

Insect herbivory results

Inoculum

Fagus sylvatica

sterilized

500 m 500 m

1000 m1000 m

2000 m2000 m

QuercusQuercus



PiceaPicea

PinusPinus

Belledonne

Soil biota lab experiment

3 seeds per pots

Seedling survival

Soil biota

Seed

lin

g

su

rviv

al

Elevation

Sterilized

Negative soil biota effect at low elevation

Soil biota results

Seedling

Adult tree

Insects herbivory

Soil µ-organismes

Increasing Degree-day sum

Decreasing Water

Ground vegetation

Negative direct interaction increase

Seedling

Adult tree

Increasing Degree-day sum

Decreasing WaterPositive indirect interaction increase

Ground vegetation

tree regeneration vulnerability to climate change ... · belledonne cerces field experiment...

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