• Aucun résultat trouvé

Virtual experimentation as a complement to observation. Application to the assessment of the future and potential for adaptation of Atlantic salmon facing climate change in Southern Europe

N/A
N/A
Protected

Academic year: 2021

Partager "Virtual experimentation as a complement to observation. Application to the assessment of the future and potential for adaptation of Atlantic salmon facing climate change in Southern Europe"

Copied!
17
0
0

Texte intégral

(1)

HAL Id: hal-02289542

https://hal.archives-ouvertes.fr/hal-02289542

Submitted on 5 Jun 2020

HAL is a multi-disciplinary open access

archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Virtual experimentation as a complement to

observation. Application to the assessment of the future

and potential for adaptation of Atlantic salmon facing

climate change in Southern Europe

Etienne Prévost, Mathieu Buoro, Cyril Piou, Julien Papaix

To cite this version:

Etienne Prévost, Mathieu Buoro, Cyril Piou, Julien Papaix. Virtual experimentation as a complement to observation. Application to the assessment of the future and potential for adaptation of Atlantic salmon facing climate change in Southern Europe. WKCCISAL Workshop on potential impacts of climate change on Atlantic salmon stock dynamics, International Council for the Exploration of the Sea (ICES). DNK., Mar 2017, Copenhague, Denmark. �hal-02289542�

(2)

VIRTUAL

VIRTUAL

EXPERIMENTATION

EXPERIMENTATION

AS A

AS A

COMPLEMENT

COMPLEMENT

TO OBSERVATION

TO OBSERVATION

APPLICATION TO THE

APPLICATION TO THE

ASSESSMENT

ASSESSMENT

OF

OF

THE FUTURE AND POTENTIAL FOR ADAPTATION OF

THE FUTURE AND POTENTIAL FOR ADAPTATION OF

ATLANTIC

ATLANTIC

SALMON

SALMON

FACING CLIMATE CHANGE

FACING CLIMATE CHANGE

IN SOUTHERN EUROPE

IN SOUTHERN EUROPE

Etienne Prévost

1,2

, Mathieu Buoro

1,2

, Cyril Piou & Julien Papaïx

1

UMR INRA/UPPA Ecobiop, Saint-Pée-sur-Nivelle, France

(3)

Atlantic salmon life cycle

Atlantic salmon life cycle

Reproduction:

Reproduction:

December

December

Embryo-laval

Embryo-laval

devpt: winter

devpt: winter

Juveniles in river:

Juveniles in river:

1 or 2 years

1 or 2 years

Migration & growth

Migration & growth

at sea:

at sea:

1 or 2 years

1 or 2 years

Smolt

Smolt

Tacon

Tacon

Seaward migration:

Seaward migration:

April

April

Return into rivers:

Return into rivers:

March - November

March - November

Homing

Homing

Eggs burried

Eggs burried

under gravels

under gravels

Very high

Very high

post-reproduction

reproduction

mortality

mortality

Precious

Precious

sexual

sexual

maturity

maturity

in males

in males

Atlantic

Atlantic

Ocean

Ocean

River

River

(4)

Climate Change : an additional stress in

Climate Change : an additional stress in

Southern Europe

Southern Europe

➢Salmon: a poikilotherm and cold water species

➢France (& Spain): southern edge of species distribution

Salmon could be strongly impacted by CC in

Salmon could be strongly impacted by CC in

Southern Europe

Southern Europe

➢Salmon is an emblematic and threatened species

Strong demand from society

Strong demand from society

and management bodies for

and management bodies for

assessing the future and potential

assessing the future and potential

adaptation of salmon to CC

(5)

How to assess

How to assess

future CC effects

future CC effects

on A.

on A.

salmon at the population scale ?

salmon at the population scale ?

Real world experiment: impossible

In silico experiments with virtual population: an alternative

option

Test diverse CC scenarios

Replication of experiments under a given CC scenario

Complementary to broad-scale approaches such as niche modelling

that ignore behavioural and evolutionary processes

INRA has developed a salmon population

simulator for virtual experimentation of CC:

IBASAM (Individual Based Atlantic Salmon Model)

(6)

Mimics a small population typical of french coastal

streams

CC is multiform

In rivers:

↗ water T°

↗ variability of flow

...

At sea:

↘ conditions for growth

...

Connect demo-genetic dynamics with riverine (T°, flow)

and marine factors (conditions for growth)

IBASAM : population simulator for the

study of CC effects on Atlantic salmon

(7)

IBASAM

IBASAM

Anadromous Migration Smoltification Ocea n Rive r Catadromous Migration Parr Matur ation Emergence Reproduction Li Fati Wi T°C Flow Survival Density Probabilistic reaction norm Wi Marine Conditions Fati Probabilistic reaction norm Probabilistic reaction norm Li Survival

River

River

Sea

Sea

Every individual of a population is explicitly represented and followed through

its life up to reproduction and/or death

Summarizes and articulates available knowledge on demo-evolutionary processes in A. salmon

Emphasis on the plasticity of the species: individuals adjust phenotype to yearly environmental variations

Explicitly represents individual genetic variability which control plasticity mechanisms

Accounts for environmental and demographic stochasticity in population dynamics

Explicitly represents the link between climate related forcing factors and individuals

(8)

First virtual experiments of CC with IBASAM

First virtual experiments of CC with IBASAM

Combining riverine and marine changes

Combining riverine and marine changes

Vendredi 1er mars 2013

27 CC scenarios tested

↗ river water T° (3 modalities)

↗ river flow variability (3 modalities)

↘ conditions for growth (3 modalities)

Time horizon: 3 decades (~2045)

300 replicates per scenario

Initial size ~215 adults returning from the sea

→ small population

(9)

Potential CC effect on salmon population

Potential CC effect on salmon population

persistence

persistence

0 : Statu quo 1 : +4°C/century 2 : +25% ↨ flow 3 : -25% marine growth Combo 2&3 Combo 1&2&3 0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20%

Extinction risk

C

C

s

ce

n

a

rio

Apart from worst case scenario, extinction risk is low at the 2045 horizon

From the scenarios tested:

Marine conditions have the strongest effect

Synergetic effect of flow variability with marine conditions

(10)

First virtual experiments with IBASAM

First virtual experiments with IBASAM

CC & selective exploitation

CC & selective exploitation

Vendredi 1er mars 2013

Selective exploitation is commonplace in salmon

Larger adults (maturing after 2 years at sea) are selectively harvested

compared to smaller ones (maturing after 1 year at sea)

CC and selective exploitation occur simultaneously →

How to compare their respective effects while

assessing their interactions?

A virtual experimentation plan:

5 CC scenarios X 5 exploitation scenarios

CC → only ↘ conditions for growth (main driver of CC effects)

Time horizon: 3 decades (~2045)

(11)

CC

CC

vs

vs

selective exploitation

selective exploitation

Phenotypic plasticity vs genetic evolution

Phenotypic plasticity vs genetic evolution

Phenotype

Prop. 2 years at sea

CC only

↘ 25% growth at sea

Genotype

Genetic threshold

triggering sexual

maturation in females

Selective fishing only

15% expl. rate 1 year at sea

↗ expl. rate 2 years at sea 15→75%

Mostly plastic response

(12)

Selective exploitation

Selective exploitation

for

for

adaptation to CC

adaptation to CC

Vendredi 1er mars 2013

Exploitation is an evolutionary force: could it be

used on purpose to foster adaptation ?

SALMOCLIM Project (INRA funded)

Virtual experimental design:

1 CC scenario X 6 selective exploitation scenarios

CC at sea and in river (strong)

Time horizon: 3 décades (~2045)

100 replicates par scenario

New version of IBASAM: includes genetic heritability

(13)

No genetic

evolution

CC → ↑ % MSW

CC → ↓ pop size

→ ↑ variability

Selective expl.:

No gain

↑ increased gap

if fishing targets

MSW fish

CC → ↓ catch

Selective expl.:

Catch maintained

if fishing targets

small fish

Selective exploitation

(14)

Demo-genetic simulation: a powerful approach to

explore CC consequences on A. salmon populations

No substitute for assessing the outcome of an

unprecedented climatic future at scales which

prevent real world experimentation

CC consequences cannot be appraised by mere

intuition

The effects of CC are mediated by a complex array

of interacting biological traits which outcome is the

resultant of contradictory forces

IBASAM:

a tool for better understanding of these interactions

A tool for management advice ? → Be patient and

very cautious

Demo-genetic simulation: a tool for making

Demo-genetic simulation: a tool for making

scientific progress

(15)

Demo-genetic simulation for assessing

Demo-genetic simulation for assessing

adaption of A. salmon to CC

adaption of A. salmon to CC

Where are we? Where to go?

Where are we? Where to go?

It is just the beginning → field of active research but still scientifically immature

Lack of understanding → any prediction is currently surrounded by (too) broad

uncertainty (to be useful)

Acknowledge Science has still little to say to advise managers

→ despite strong demand for answers science must be cautious not to oversell preliminary results

Not at the edge of population extinctions even in Southern Europe → must take

advantage of the next two decades to improve :

Understanding of CC effects on A. salmon with

IBASAM: considerable room for

improvement

Improving realism of genetics of plastic traits → age at maturity reaction norm

Interacting populations → metapopulations

Scientific advice to A. salmon population management

Conceive management options that are robust to uncertainties

(16)

First virtual experiments with IBASAM

First virtual experiments with IBASAM

What have we learned ?

What have we learned ?

Some qualitative (not quantitive) results :

Complexity of interactions network →

unexpected and non-intuitive outcomes

e.g. first results on population viability

CC may have strong/rapid demographic and

phenotypic effects with (too?) little/slow genetic

evolution

Selective exploitation :

might not be a way to foster adaptation

(17)

Thanks for your attention

Références

Documents relatifs

In conclusion, War and the Politics of Identity in Ethiopia o ffers a methodical, original, and highly informed account of the contested political identities that have marked Africa

Two genes, ODC and TRYR, showed a signi ficantly different change in expression level (slope of the expression curve) between the 2 groups of in vitro Sb V -S and Sb V -R

The first trial was initiated in the United States by the Gastrointestinal Tumor Study Group (GITSG) in 1974 [23], which was slow to accrue and was terminated early following

The last and single autopsy case of proven classic analgesic nephropathy, detected only with the present sophisti- cated histological study at the end of the year 2000, can thus

Series of future climate data coupled with the calibrated crop growth model APSIM were then used to simulate impacts of climate change on crop production and evaluate

OF OF ATLANTIC SALMON ATLANTIC SALMON FACING FACING CLIMATE CHANGE CLIMATE CHANGE IN IN SOUTHERN EUROPE SOUTHERN EUROPE.. Etienne Prévost 1 , Cyril Piou 1,2 , Julien

(Pramova E., Locatelli B., Djoudi H., Somorin O., forthcoming. Forests and trees for social adaptation to climate variability and change. WIREs Climate Change, online first.