Download 1.1. Agronomic value and provisioning services of multi

Agronomic value and provisioning
services of multi-species swards
C. Huyghe, I. Litrico, F. Surault
INRA, France
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Outline
• Introduction
• Theoretical bases
• Agronomic performances of multispecies
swards
• Consequences for breeders and farmers
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Introduction
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Introduction
 Biomass production
 Feeding value
 Persistency
 Preservation of the environment


Less nitrate leaching
Protection of the biodiversity
 Social acceptability

Meeting the aversion risk of farmers,
i.e. reducing the variation among years
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Increasingly
important stakes
 In a context of sustainable agriculture
Usual stakes
 A real need to improve agronomic value of
grasslands
Introduction
 In a context of scarcity (SCAR, 2011)
 Less fossil resource of energy and nutrients
 Less labour resource
 A new paradigm: paradigm of efficiency, through
valorisation of ecosystem services. This needs
implementation of transitions
 Technological innovations




Ecological intensification: « yield gap »
Accelerating adoption of research results and innovations by
farmers and industry: « innovation gap »
Making the agri-food system more resilient: « resilience gap »
Encouraging economic stakeholders to take risks: « sociotechnological gap »
 The Millenium Ecosystem Assesment (2005) is providing
the framework
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Introduction
 The hypothesis of the presentation
 Multispecies swards make it possible to improve the various
ecosytems services and particularly primary production
 This is true both in temporary grasslands and permanent
grasslands
 Increasing species and functional diversity leads to a
higher biomass production in a given year and better
persistency
 Overyielding
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Theoretical bases explaining
community functioning
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Theoretical bases
 A community structure (assembly) may be explained by
 Habitat filtering
 Niche differentiation
Trait value
Habitat filtering
Assembled species are meeting
the same filters:
Niche
differentiation
•
•
X
X
They have common functional
traits: Response traits
This is relevant with the
redundancy of species in plant
communities and redundancy of
trait (response trait) values in
species
Assembled species are meeting
the different niches :
•
Differences of trait values among
species
Realized community
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Theoretical bases
 What are the filters?
 The environmental conditions.
 Agronomic practices


Defoliation regime (grazing vs. cutting)
Nitrogen fertilisation
Example from Suding et al (2005):
•
•
In a group of experiments across US
After N fertilisation, the dry matter production increased
while the species diversity decreased (except in
marshlands)
 The filters determine


Number of plant species
Identity of species - Functional groups (i.e. grasses,
legumes, dicots)
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Theoretical bases
 What does happen in a multispecies sward: how to
achieve overyielding?
Ecosystemic processes
Facilitation Complementarity
Neutral
Competition
Number of species
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Theoretical bases
Competition
Facilitation
Increasing
resources
Actual niche
Actual niche
Competition
Predation
Recruitment
Refuge
against
predation
Increasing
recruitment
Pests and
diseases
•
•
•
Fundamental
niche
Facilitation may reduce the habitat filtering and
Improving
increase the number of species
habitat
Competition, facilitation and complementarity are due
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to functional traits: effect traits
A G R I increasing
C U L T U R E the
Positive effects should increase when
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functional diversity
Fundamental
niche
Data from the real life
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This paper has 736 citations (in Web
of Science, 28/05/2012)
A seminal paper:
Hector et al, 1999 in Science
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• Guo et al (2006) :
a study over several
years and several sites
in the US:
a trend towards
overyielding but with a
plateau (community
saturation)
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E N V I R O N MM2
E N Poitiers,
T
8 décembre 2010
Kirwan et al, 2007: mixtures with 4 species
grass – legumes with species adapted to experimental sites
 : Monocultures; : Associations
Beyond the expected effect due to functional diversty of grass and legumes, a
positive effect was detected with 2 grass species (> 1 species) and 2 legume species
(> 1 species)
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An outstanding experiment from Iena: increasing the number of species
reduces the disease pressure
A true situation of facilitation
% infection
permodule
module
per
% infection
Mean infection score per plant
35
30
25
20
15
10
5
0
1
2
3
Number
ofoffunctional
groups
Number
functional groups
Number of sown species
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E N Poitiers,
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8 décembre 2010
4
Optimizing species and
functional diversity
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Optimising the species and functional diversity
Environment
Agronomic
practices
In mesotrophic
environments
Facilitation Complementarity
Habitat filtering
Pool of species
(sown or naturally
available)
Overyielding
Possible reduction
of the species
diversity for effect
traits
(drift)
Reduction of the
species diversity
for response traits
Competition
In highly fertilised
environments
Little Overyielding
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Diversity and species identity
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Species diversity and identity
 When increasing the number of species, the probability
of getting through the habitat filtering increases
 Adaptation of species to environments and agronomic
practices
 Cocksfoot and tall fescue are becoming dominant in dry
climates: response trait to dry environments
 Species may have a mean beneficial effect on the plant
communities: the concept of essentiality
ES=Yi/Yd
Intact community
S
Community without S
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Species diversity and identity
 A decision toolkit for farmers and advisors
 Choosing the right species:
 Adaptation to environmental conditions and agronomic
practices
 Optimizing diversity
 Maximising the functional diversity for effect traits
 Homogeneity for response traits and agronomic value
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Is breeding possible in these
conditions?
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Genetic diversity
 How to integrate the species diversity as a constraint for
breeding?
 A decision toolkit for breeders
 The role of within variety genetic variance
 Revising the breeding objectives



Breeding for response traits
 Adaptation to environmental conditions and agronomic
practices: where are the markets?
 Breeding for biomass production is positive for adaptation
Disease resistance is less important in communities
Improving feeding value
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Conclusions
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 Increasing species diversity has in nearly all situations
positive effects on primary production and no negative effects
on other ecosystem services
 It meets sustainability requirements
 It is relevant with the paradigm of efficiency
 It is compatible with further agronomic and breeding
progesses
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Acknowledgements:
• Multisward project and partners
Thank you for your attention!!!
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