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Presentació per part de Sandra Lavorel (Directrice de Recherches CNRS, LECA Labaratouir d'Ecologie Alpine, France) en el marc de la jornada del projecte CIRCLE 2 MOUNTain co-organitzat per l'Oficina Catalana del Canvi Climàtic durant els dies 26 i 27 de setembre de 2013.
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Adaptation of mountain regions to drought recurrence in a context of global change
Baptiste NETTIER, Irstea
Sandra Lavorel, Pénélope Lamarque, CNRS - LECA Benoît Courbaud, Laurent Dobremez, François Véron, Irstea
Richard Bonet, Ecrins National Park
Recent climatic trends in the French Alps
Precipitation T min T max
A context of great uncertainty
SECALP project
Objective: To analyse adaptation mechanisms for mountain regions in the face of climate change, especially recurring droughts
– Mechanisms of ecosystem resilience and transformation
– Processes of adaptation for livestock farming and forestry
– Expected effects of climate change scenarios, in the context of social transformations
Guidelines for supporting managers through policy and infrastructure
Strategies for long term observation
Ecosystem adaptation
Land use adaptation
Scenarios and pathways to sustainable
management
Long-term observation system
SECALP: An integrated conceptual framework
2 territories of the French Alps LTSER
Villar d’Arène, Oisans Vercors
• Vercors: • Subalpine Extern Alps • Dairy farming systems, suckler cattle and
sheep farming systems, transhumants
• Oisans: • High mountain Intern Alps • Suckler cattle and sheep farming systems
21 sites sampled in 1988, 2001 and 2011 Grande Cabane grassland (Vercors)
Grazed / ungrazed plots since 1988
• Small changes and stability in grazing value • Grazing stabilises composition and increases diversity even under drought
-0.5 3.0
-0.5
2
.0
AP11
AD11 BP11
BD11
DP11
DD11
EP11
ED11 FP11
FD11
HP11 HD11
IP11
JP11
KP11 KD11
AP88
AD88
BP88
BD88
DD88
DP88 ED88
EP88
FD88
FP88
HP88
HD88
IP88
JP88
KD88
KP88
AP01
AD01
BP01
BD01 DP01 DD01
EP01
ED01
FP01 FD01
HP01
HD01
IP01
JP01
KP01
Dry grasslands Mesic grasslands
Forest clearings
Expected trend from 1988 to 2011 under strong drought response
No shift towards drought tolerant species = stability
A detectable effect of climate change on summer pastures?
© G. Loucougaray
Experimental drought and heat wave simulation on Lautaret and Vercors grasslands
- ↘80% summer precipitations + 1°C night warming
- Extreme event (~2003): one month without precipitation (Lautaret & Vercors) + heat wave +6°C (Lautaret)
- Mowing (0/1) – combined with the climate treatment
Lautaret
Vercors
Limited sensitivity to drought: transient response (Vercors) or resistance (Lautaret) Short term: prevailing effects of management Long term: feedbacks via nutrient cycling
© S. Aubert © S. Lavorel © G. Loucougaray
1900 1920 1940 1960 1980 2000
05
15
25
35
Mort
alit
y r
ate
Lanslebourg
1900 1920 1940 1960 1980 2000
05
10
15 Queige
1900 1920 1940 1960 1980 2000
01
23
4
Mort
alit
y r
ate
Engins mortality rate
CI
1900 1920 1940 1960 1980 2000
0.0
0.5
1.0
1.5
Méaudre
Are there discernable effects of drought years on tree mortality?
• Overall low mortality rates and no long term trend
• Links to climate variables: – Strongly predominant effects of storms (yr n or n-1)
– No effect of the Palmer Drought Severity Index (Climatic Research Unit, Norwich)
– 2nd order effect of increased precipitation
Perception by farmers and shepherds of consequences of droughts since 2003, and reactions
• Decrease in forage resources • Decrease in water availability for summering herds • Few vegetation dynamics – “Invasions” by undesirable
species, superficial soil degradation
• Signs of climate change - “Fewer storms in summer"
Adaptations at farm scale
– Impacts and adaptation options differ widely across farming systems (level of reliance on winter fodder)
– Mainly tactic responses without long-term adaptation : decrease of grazing pressure, fodder purchase
– Pastoral systems have integrated the hypothesis of increasingly frequent droughts into their functioning and made structural adaptations
– Drought is only one risk among others for livestock systems: socio-economic context, structural constraints
What adaptations in case of harder droughts ? What consequences for ecosystems
Nettier et al., 2010
Perception by foresters of consequences of droughts since 2003, and reactions
• 2003: strong defoliation on drier / thinner soils, but not in productive stands; good recovery with only limited mortality
• Beetle damage on spruce in 2004-5
• Foresters are aware of climate change and the risk of recurring droughts, but are yet to see climate change effects
• Adaptation responses are limited:
– Manage stands towards species and structural diversity
– Reduce the share of spruce in regional plans
– Infrastructure for increased fire risk
– Inconclusive attemps to plant more southern species (frost)
2003
2004-5
Building of prospective scenarios
• Co-construction with a group of local experts
• 4 contrasted scenarios, combining:
– 2 climatic contexts
– 2 socio-economic contexts
• Time path: 30 years trends + precisions for the next 4 years (CAP reform)
• Return to the farmers and foresters : strategic adaptations
– Storylines
– Drawings (landscape changes)
– Graphs (forage productivity, CAP subsidies, product prices)
• With local experts : consequences at territorial level
“Intermittent” climate
“Territorial” context
Scen.3
Scen.4
Scen.1
Scen.2
“Shock” climate
“Global” context
Reactions to scenarios: main trends
Intermittent + Global Leverage system flexibility, increase surfaces, decrease
livestock as a last resort
Intermittent +
Territorial Leverage system flexibility
and increase surfaces + develop direct sales
Shock + Global Decrease livestock and take on off-farm; put a stop to
the farm in some cases
Shock + Territorial Decrease livestock,
develop direct sales + agri-tourism
Territorial On-farm
diversification
Shock Decrease livestock
Intermittent Adapt to the situation as in the past + increasing
system flexibility to limit fodder purchases
Global Offset loss of
income through an
activity outside the
farm / stop the farm
A role playing game to simulate grassland management according to the different scenarios
Results
Local International
a) Current context
Game board (Round 4)
Decisions-basedrules
b) Scenarios
7%12%
11%
7%22%
42%
Actuel
1 2 3 4 5 7
14%
14%
6%2%
22%
42%
Choc territorial
3 3f 4 4f 5 7
9%1%
15%2%
3%25%
2%
42%
Choc global
1 2 3 3f 4 5 5f 7
13% 6%
8%1%
6%2%22%
0%
42%
graduel territorial
1 2 3 3f 4 4f 5 5f 7
11%2%
13%2%
4%1%24%
1%
42%
graduel global
1 2 3 3f 4 4f 5 5f 7
Game board (Initial state)
Inte
rmit
ten
tD
rast
ic
Lamarque et al., 2013
Dro
ugh
t
Socio-political context
Projection of the game on the territory
Ecosystem services modelling at the landscape scale
Agronomic value Cultural value
Pollination value Soil C stocks
Regulation value Total ES value
Lavorel et al. J. Ecol. 2011
Lessons from the scenarios
Effects of the climatic hypothesis • Intermittent drought context already integrated by farmers, even if the forage
systems are not always adapted and many still have to buy fodder.
• Shock climate context difficult for farming systems degradation of economic and work conditions + important farming system and land use tranformations
Effects of the socioeconomic hypothesis • Farmers’ preference for the territorial context: more adapted to mountain farming;
many farmers had already diversification projects
• Global context: interesting subsidies easy to get, but discordant with conception of job (AEM for wild nature or carbon storage with planting trees…)
• Most of the farmers ready to take out further commitment (diversification)
• Local experts were surprised, even if such changes are already
emerging
• They underlined a need of collective facilities in order to support
diversification (local abattoirs, sales outlets, formation, structuration of
short distribution channels…)
A need of territorial action to accompany adaptation
Conclusion: resilience or fragility of mountain territories?
• Ecosystem adaptation to environmental variability – Buffer mechanisms: e.g. plant belowground reserves, rapid soil microbial
responses
– BUT:
• thresholds?
• Sensitivity to practices evolutions : fragile equilibrium
• Adaptation of actors to environmental variability – Mainly tactic short term responses
– Resistant systems but limited resilience ?
• Systems under strong constraints – Biophysical limits to production (short growth period, slope…)
– Rigid rules (CAP, land access regulations …)
• A need of local knowledge on ecosystems functioning in this changing context – How climate, practices, and vegetation co-evolve ? How to manage it ?
– Need of dialogue and cooperation at a territorial level
An interdisciplinary and participative long term monitoring system
Different protocols to survey vegetation, climate, management
A sample of diversified alpine pastures and farms
Co-construction of knowledge
A conceptual model for data analyzing
An interdisciplinary and participative long term monitoring system
Thank you for your attention !
Three different reasoning and choices
“I would reduce the economic impact of droughts by diversifying my productions and my activities” Cereal, poultry workshop, agri-tourism or city work, according to the context
“I would adapt but without diversifying my productions because I want to keep my livestock farmer identity” Possible direct sales of meat, salaried work, but in connection with livestock
“I wouldn’t change my system because it is already robust enough” Oversized haymaking surfaces or source of income from another activity
• differences in livestock farmers “identity” according to the types of farming systems:
• Oisans “High mountain” systems : produce hay vs. buy hay
• Vercors “Fodder” systems: type of production
• Vercors “Pastoral” systems: “pastoralist” vs. “grass farmer”
Uncertainties on expected climate trends… Number of days of heat wave
Length of drought
Mean max summer T
Mean annual precipitation
Intermittent
Regional
Global
Shock
Four scenarios, combining climatic and socio-economic contexts
2. BUILDING OF PROSPECTIVE SCENARIOS
2 climatic contexts
Intermittent • Spring or summer droughts alternating with wetter years • Species resilience • In a drought year : 1st cut yield = 60% of a wet year
Shock • 4 consecutive spring drought years • Rangeland: deterioration of herbaceous plants • 40% loss in fodder resource for long term
2 socio-economic contexts
Global • Roles of agriculture: attractive landscape for city dwellers; carbon storage
• Product prices : ≈ -20% (Organic:-10%) • CAP pillar 1: -20%, decoupled, minimum guaranteed • AEM: bonus for grassland, planting trees
Territorial • Roles of agriculture: local quality products • Product prices:≈ -20%,except organic & PDO label: maintained • CAP Pillar 1: -20% • AEM: Bonus for biodiversity, commitment to results
Effets des scénarios sur les services écosystémiques
0
20
40
60
80
100SOM
RetentNO3
Gbio
LitterMass
CPC
FloweringOnset
PlantDiv
NMP
0
20
40
60
80
100SOM
RetentNO3
Gbio
LitterMass
CPC
FloweringOnset
PlantDiv
NMP
Lamarque et al., in prep.
Land management types
Soil organic matter
Nitrate retention
Fodder production
Standing litter
Fodder quality
Flowering onset
Plant diversity
N mineralization
Current
Scenarios
Drastic drought induces a shift from production and cultural services of interest to local stakeholders to higher levels of regulation services of interest to stakeholders outside the study site
Management change scenarios in response to combined climate and social chanee
Local International Future scenarios
7%12%
11%
7%22%
42%
Actuel
1 2 3 4 5 7
14%
14%
6%2%
22%
42%
Choc territorial
3 3f 4 4f 5 7
9%1%
15%2%
3%25%
2%
42%
Choc global
1 2 3 3f 4 5 5f 7
13% 6%
8%1%
6%2%22%
0%
42%
graduel territorial
1 2 3 3f 4 4f 5 5f 7
11%2%
13%2%
4%1%24%
1%
42%
graduel global
1 2 3 3f 4 4f 5 5f 7
Inte
rmit
ten
t D
rast
ic
Current situation