how biodiversity underlies ecosystem services in...
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How biodiversity underlies ecosystem
services in terrestrial systems
Sandra LAVORELLaboratoire d’Ecologie Alpine
Centre National de la Recherche Scientifique (CNRS),
Grenoble, FranceResearch priorities to sustain Ecosystem Services
Conference of the European Platform for Biodiversity
Research Strategy
Budapest, 27 April 2011
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What good is biodiversity for humans?
• Nothing !
� Intrinsic value of nature
• Essential for life on Earth
� Role of biodiversity for
ecosystem functioning and the
biosphere
• Services to society
� Nature’s contributions to
individual et collective well-being
• New objectives :
� Accounting for nature’s services
in private and public decisions
Presentation overview
• The role of biodiversity in ecosystem service provision– Review of evidence from temperate agroecosystems
• Quantifying the spatial distribution of ecosystem services– Functional ecological production functions for ecosystem services– Synergies and trade-offs among ecosystem services and their
biophysical basis– Can we preserve biodiversity by focusing on ecosystem
services?
• Research challenges
Ecosystem Services
The benefits people obtain from ecosystems
Millennium Ecosystem Assessment 2005
“Demystification” of ecosystem services
Lamarque et al, 2011. Comptes Rendus Biologies5
Human
input(s)Structure(s) or
process(es)Grass species
Nutrient cycle
Function(s)Green biomass
Phenology
Crude protein content
Service(s)Fodder production
Grasses for grazing
Benefit(s)Harvest fodder
Grazing
Cheese or meat
de Groot et al,
2002, Teeb
2009, Haines-
Young &
Potschin (2010)
Ecological structure,
habitat, ecosystem
properties and supporting
services
The potential that ecosystems
have to deliver a service.
‘Things’ needed to deliver
services
the direct and indirect
contributions of ecosystem
to human well being
Welfare gains generate
MA, 2005 Supporting services Benefits people obtain from ecosystem
Daily (ed), 1997 Complex natural cycle The conditions and processes through which natural
ecosystems, and the species that make them up, sustain
and fulfill human life
… … … …
Feedback effects of human actions
What is an ecosystem service ?
Human
input(s)
Structure(s) or
process(es)
Grass species
Nutrient cycle
Function(s)
Green biomass
Phenology
Crude protein content
Service(s)
Fodder production
Grasses for grazingBenefit(s)
Harvest fodder
Grazing
Cheese or meat
Ecological components Social components
Lamarque et al, 2011. Comptes Rendus Biologies
• Ecosystem services
mapping studies often
use land use / land
cover – ES identity
• Source of uncertainty
in estimates of
ecosystem services
Eigenbrod et al. J. Appl. Ecol. 2010
Components of biodiversity
Diaz et al. PLoS 2006
Diaz et al. PLoS 2006
Effects of different biodiversity components on ecosystem services
Quantifying the effects of biodiversity on ecosystem
services: Methodology
Ecosystem service
Soil fertility
Ecosystem processes
DecompositionMineralisationPlant use
Organism or landscape structure:
Species diversity, identity;Functional diversity, identity;Trophic complexitySpatial heterogeneity
PlantsSoil faunaSoil microorganisms
Ecosystem services in agroecosystems
Lavorel et al. 2009
Modified from Zhang et al. 2007
AGRO-ECOSYSTEMS
INPUT SERVICES
MARKET PRODUCTION
ADDITIONAL PRODUCTION
Soil structureWater availabilityFertilityMicroclimateBiotic controlInvasion controlPollinationLivestock health
Primary production:- Efficiency- Stability: biotic controls- Stability: abiotic variability- Fodder production stabilityLivestock production:- Efficiency- Fodder quality- Quality of animal productsOther marketable products
Water productionWater qualityClimate regulationFire regime regulationHuman healthBiodiversity conservationCultural & aesthetic value
Input services
(1) Ressources for production
=> Role of functional diversity for the maintenance of fertility, but
these effects are relevant only when fertilisation is low / organic
Soil macrofauna : In presence of several functaional
groups (earthworms, isopods, chilopods) species
number has no effect on decomposition. Functional
diversity is the driving variable.
Litter decompositionNet effet of diversity
Functional dissimilarity
Soil nitrogen concentration
Number of species
+ legumes
0 legumes
Grassland or crop plants:
Plant species richess increases nitrogen
use, but this effect is mostly that of
legumes
The increase in abundance and diversity of
pollinators near grassland results in increased
fruiting
Distance to grassland (m)
Nu
mb
er o
r se
eds
/ fr
uit
Input services
(2) Biotic regulation : Pollination
=> Importance of maintaining sources of pollinators in the landscape
The abundance of wild bees decreases with
the distance from plants (crops) to be
pollinated to semi-natural grasslands -
pollinator sources
Distance to grassland (m)
Ob
serv
ed w
ild b
ees
Production – (1) Crop yields
Crop rotation experiment:
- Variation of the numberof species in the rotation and of the number of legume species used as cover crops
- No fertiliser or pesticidesNumber of species
Yield
Corn Soybean
Wheat Total yield of the rotation
- Doubling of corn yield ~
mean regional yield.
- Less clear for other crops.
- Improved nitrogen
resources but no effect on
weeds except in wheat
Smith et al. 2008
Plant production – (2) Stability
Number of sown species Number of sown species
Coefficient of variation of aboveground biomass
- Decreased interannual variability in the face of climate variability?
- As many experiments find a positive effect of grassland richness as not, without
an understanding of causes.
- Grassland yield stability through variation of yields of individual species.
- Appears to promote stability of fodder production at farm scale.
� No clear evidence for the insurance hypothesis
Non-marketable servicesAesthetic and cultural values
Conventional agriculture
Organic farming
Small-scale heterogeneity
Butterfly diversity
Main effets of biodiversity on ecosystem services
provided by temperate agroecosystems
• Dominant species and their functional characteristics
– Input services – soil stability, fertility, water availability
– Yield of permanent grasslands and benefits for animal production
– Services at larger scales: water quality, climate regulation, fire mitigation.
• Functional complementarity
– Fertility, yields: legumes – grasses; crop rotation
– Soil stability, water availability, yields: plant species with differing morphology,
phenology or rooting depth
– Fertility: soil macrofauna
– … but remains to be elucidated for most services
• Ex. effects of species diversity of biocontrol agents and pollinators
• Role of spatial diversity in landscapes
Executive summary and synthesis report on temperate agroecosystems available at:http://www.inra.fr/les_recherches/agriculture_et_biodiversite_nouveau_defi
Challenge 1
At which scale should biodiversity be managed to accrue ecosystem services?
Rel
ativ
e be
nefit
of
biod
iver
sity
to th
e se
rvic
e
Lan
dsc
ap
e-s
cale
spe
cie
s ri
chn
ess
Landscape type Landscape type
extensive
intensive
extensive
intensive
Rel
ativ
e be
nefit
of
biod
iver
sity
to th
e se
rvic
eBiotic regulation
input services
Resource
input services
Type de paysage Type de paysageLandscape type Landscape type
Birds, plants with long dispersal
Highly mobile insects
Soil fauna and microorganisms, plants with limited
dispersal, Insects with restricted mobility
Challenge 2
Understanding the effects of management on multiple
ecosystem services through their effects on biodiversity - Synergies and trade-offs across ES
Services
Management intensity
Maintenance of fertilityAnimal health, ingestion, cheese
quality, water quality
Fodder production; milk production
Example:
Services from plant and microbial
diversity in permanent grasslands
Biodiversity and multi-fonctionality:
Example of agroforestry
Traditional agroforestry Modern agroforestry
Challenge: Using ecological knowledge to understand
ecosystem services trade-offs and synergies
Fertilisation, mowing
Intense grazing
Abandonment
Resource conservation: leaf life
span, nutrient and water use
efficiency, C-based defenses
Resource acquisition: specific
leaf area, specific root length,
tissue [N]
PL
AN
T
Slow biogeochemical cycles
Litter accumulation
Low palatability
Fast biogeochemical cycles
High NPP
High palatability
FU
NC
TIO
NS
ER
VIC
ES
Carbon sequestration
Soil conservation
Pest control
Fodder production
Soil nutrient supply
Invertebrate diversity
Lavorel & Grigulis in prep.
Land use
DIRECT EFFECTS
Ecosystem properties
Soil properties
Plant diversity
Topography
Biodiversity responses
Biodiversity
effects = INDIRECT
EFFECTS
Quantifying ecosystem services based on land use
Landmanagement
Soil properties
Plant diversity
Topography
Biodiversity responses
Ecosystem properties
Biodiversity =
INDIRECT EFFECTS
DIRECT EFFECTS
Quantifying ecosystem services
accounting for biodiversity effects
Lavorel et al. J. Ecol. 2011
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Terraces (crops)
Permanent
grasslands (mowing)
Summer range
Spring+autumn grazing
Mowing
Summer grazing
Mowing & unfertilised
Mowing & fertilised
Quantifying ecosystem services depending on land use
and species functional traits at Lautaret (France)
Production functions of ESincorporating functional diversity effects
Fodder quantity Fodder quality Flowering phenology
Date of flowering Phenological diversity
+ + +
Sum of mapped values for each contributing
Ecosystem Property
Grassland agronomic value
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Plant height
Leaf Nitrogen Conc.
Plant height
Leaf Dry Matter Content
Trade-offs and synergies
in ES provision
• Methods for quantitative analysis of spatial association
among services
– Counts of number of ES provided per pixel
• ES hot spots, cold spots etc.
– Overlap analyses
– Multivariate analyses
Counts of overlapping ecosystem services
Willemen et al. Ecol. Ind. 2009
Mapping multiple ecosystem services
Agronomic value Cultural value
Pollination value Soil C stocks
Regulation value
Lavorel et al. J. Ecol. 2011
Total ES value
Overlap analyses
• Analyse spatial overlap among areas of provision for different
services – Chan et al. PLoS Biology 2006
• Sensitivity to threshold of ES provision determined by decision makers – comparing 3 perspectives
Agronomic Aesthetic Conservation
Gos & Lavorel in prep.
Multivariate analyses of
Trade-offs and Synergies in ES provision
-0.4 -0.2 0.0 0.2 0.4
-0.2
-0.1
0.0
0.1
0.2
Principal component analysis
Factor 1
Fa
cto
r 2
***
*
*
*
**** *
**
*
*
***
*
*
**
**
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
**
*
* *
*
***
* **
*
*
**
*
-15 -10 -5 0 5 10 15
-50
51
0
Soil Carbon
Green Biomass
Litter Mass
Crude Protein Content
FD Flowering Onset
Plant Diversity
Fertilised + mown
terraces
Unmown
Festuca
grasslandsMown Festuca
grasslands
Unfertilized
+ mown
terraces
Unfertilized
+ unmown
terraces
Grazed summer
grasslands
(58% variance)
Cultural heritage valueLavorel et al. J. Ecol. 2011
Challenge 3: Trade-offs and synergies
in ES provision in space and time
• Services trade-offs in space and time
– As a result of land use change (scenarios + past)
– In time: specify time scales for different ES; need method for trading off e.g. time discounting model from restoration ecology
– In space:
• Build on analysis of ‘hot spots’ and spatial comparison between provision
and demand
• Larger scales:
– import of ES from outside the modelling geographic domain (EU)
Trade-off analysis for land use scenarios (SENSOR)
Paracchini et al. Ecol. Ind. 2009
Using discounting methods to assess temporal trade-offs
Challenge 4: Biodiversity and Ecosystem ServicesHow do they overlap?
Egoh et al. Biol. Cons. 2009
Chan et al. PLoS Biol. 2006
‘Targeting ecosystem services directly
can meet the multiple ecosystem
services and biodiversity goals more
efficiently but cannot substitute for
targeted biodiversity protection
(biodiversity losses of 44% relative to
targeting biodiversity alone).’
Conclusions
• Biodiversity has an intrinsic value, but also plays an essential
role for the functioning of ecosystems and the provision of
ecosystem services (ES) to society
• Strong determinism of ES by land use via its effects on biodiversity
• Research challenges:– Scales of biodiversity management to sustain specific ES
– Biodiversity and multi-fonctionality: novel biophysical approaches to understanding synergies and trade-offs across services
– Trade-offs and synergies in ES provision in space and time
– Biodiversity and Ecosystem Services - How do they overlap?
� Implications for land management and policy
Nelson et al. 2009 FREE
Mapping Ecosystem Services for the
assessment of alternative land use scenarios
Input services: (3) Pest biocontrol
Beetle bankFlower strips
Agroforestry
Grass strips + woody species
Field edges Within fields
Managing complexity favours populations of control agents and
decreases pest populations
Functional complementarity :
Mechanisms for increased biomass production
Dimitrakopoulos & Schmid 2004
Soil volume
Soil volume
Complementarity in root architectures:
underlies the expression of species
richness effects
Soil nitrogen concentration
Co
rn y
ield
(t/h
a)
Nb species in rotation
Nb legumes
Smith et al. 2008
Plant species richness increases
nitrogen use, but this effect is
dominated by that of legumes
Diversity of fodder
Production – (3) Animal production
Stade de développement
> 70% Graminées> 50% et < 70% de graminées et riche en RGA
60
65
70
75
80
85
1 2 3 4 5200
300
400
500
600
Teneur
en p
aro
is v
égé
tale
s
(g/k
g D
M)
60
65
70
75
80
85
1 2 3 4 5
> 50% dicotylédones et riches en plantes feuillues> 50% dicotylédones et riches en plantes à tiges fibreuses
Dig
estibili
té
(%)
Stade de développement
> 70% Graminées> 50% et < 70% de graminées et riche en RGA
60
65
70
75
80
85
1 2 3 4 5200
300
400
500
600
Teneur
en p
aro
is v
égé
tale
s
(g/k
g D
M)
60
65
70
75
80
85
1 2 3 4 5
> 50% dicotylédones et riches en plantes feuillues> 50% dicotylédones et riches en plantes à tiges fibreuses
Dig
estibili
té
(%)
Composition of ingested biomass
Increased quality of products:
Increased sensory quality of
mountain cheeses (10 studies)
Dig
esti
bili
ty (
%)
Non-marketable services : (1) Water quality
Wertz et al. 2007↓ Density denitrifying bacteria
Decrease in genetic diversity by
dilution of the denitrifying
community
No effect on denitrification:
Strong functional redundancy
among soil microorganisms
Which benefits can agriculture
draw from biodiversity?
• Benefits of biodiversity:– Small with respect to short-term production losses for inputs relating to
ressources
– Strong if not irreplaceable for input services relating to biotic regulation
– Plant and animal production can benefit from these services given adapted management (farmer technicity)
– Key services for society outside of direct farm income
• Keys for sustainable agriculture:– To better understand and manage functional diversity
– To manage landscape diversity
– To understand and negociate synergies and trade-offs between services
• Feasibility and acceptability to farmers
Limits of knowledge
and research priorities
• Interests and limits of manipulative experiments using assembled communauties� Strong heuristic contribution, but results remain to be validated under agronomic
conditions
� Limited levels of manipulated diversity; species and functional group identity, community structure
� Interactions with factors that are actually manipulated by management: fertilisation, disturbance
� Long-term experiments, including agronomic experiments
• Majority of studies: effects on plant diversity on plant production� Roles of other organisms and range of services associated with agroecosystems: soil,
pollinators, pest biocontrol agents
� Role of biodiversity for production and agroecosystem stability poorly studied
• Spatio-temporal dimension of biodiversity:� Dynamics of recolonisation after local extinction in the context of agricultural landscapes
� Ecosystem engineering
� Modelling to access larger / longer scales
• Amplitude of biodiversity effects with respect to those of exogenous inputs, and actual value to the farmer in terms of savings on inputs and yields
Species-level functional traits:
Fodder digestibility
Relation between digestibility and (A) growing degree days to flowering, (B) leaf dry matter
content for 13 grass species from permanent grasslands grown in monocultures
� Species traits determine digestibility
� Relationship confirmed at community level (weighted mean): Garnier et al. unpublished
Pontes et al. 2007
Community weigthed mean traits:
Soil water availability
Gross et al. New Phytol 2008