A presentation made at the WCCA 2011 event in Brisbane, Australia.

1. Different policy scenarios to promote
various targets of biodiversity
L. Mouysset, L. Doyen, F. Jiguet
mouysset@mnhn.fr
CNRS - National French Museum,
Paris, France WCCA 2011 - Brisbane

2. Context
1.00
0.95
Indicateur oiseaux
• Decline of farmland birds caused by the
0.90
Bird abundances
agricultural changes. All sp.
0.85
• Agri-environmental schemes lead to
0.80
mixed results. Farmland sp.
0.75
• One limit of the agricultural evaluations
0.70
is the land-use focus.
1990 1995 2000 2005
Année
Years
 There is a need for approaches integrating economic
criteria in conservation problems.
• Dynamic and landscape-level bio-economic modelling to analyze the impact of
agricultural public policies on biodiversity.
• Focus on a taxon (common farmland bird) rather one or two species.
• Use various indicators to depict different characteristics of the communities.

3. Data
• Biodiversity data
2km
20 farmland specialist species
!
! !
14 generalist species ! ! !
!
! ! !
Abundances from 2002 to 2008
Kriging of abundances
• Agricultural data
PRA as a portfolio of 14 agricultural
systems
Gross margins and proportions of the
Utilized Agricultural Area
From 2001 to 2008

4. Conceptual framework
Public decision maker
Economic uncertainties Incentive scenarios
Standard regional farmers
Income maximization
Agricultural land uses
Beverton-Holt dynamics
Bird abundances
Ecological indices

5. The scenarios
• The scenarios
SQ : Statu Quo scenario : without incentives
CR : Crop scenario : subsidies to crops
GL : Grassland scenario : subsidies to extensive grasslands
DS : Double Subsidies scenario : subsidies to crops and extensive grasslands
HQE : High Quality Environmental scenario : taxes to crops and subsidies to
extensive grasslands
Bio-economic scenarios from 2009 to 2050 with decreasing incentives:
$ 0
100 runs for each scenario with different random economic uncertainties.

6. The indicators
• The indicators
2 size community indicators :
- the Farmland Bird Index
- the Generalist Bird Index
1 species richness indicator :
- the Shannon Index
2 strutural indicators :
- the Community Specialization Index
- the Community Trophic Index

7. Results
$ 0 $ 0
1.6 1.10
1.5
Generalist Bird Index
Farmland Bird Index
1.05
1.4 HQE
1.3
GL
1.00
DS
1.2
0.95
1.1
CR
1.0
0.90
0.9
0.8 0.85
2000 2010 2020 2030 2040 2050 2000 2010 2020 2030 2040 2050
Years Years
 FBI and GBI discriminate the scenarios.
 FBI is more sensitive than GBI.
 Scenarios promoting Grassland are the more effective.
 Trends to go back to the baseline value around 2030-2040.

8. Results
$ 0
1.015
1.010
Shannon Index
1.005
DS
GL
1.000
HQE
0.995 CR
0.990
2000 2010 2020 2030 2040 2050
Years
 CR scenario leads to a decrease of species richness.
 Trends to go back to the baseline value.

9. Results
$ 0 $ 0
1.015 1.015
Community Specialization Index
Community Trophic Index
1.010 1.010
GL
1.005 1.005 HQE
DS
1.000 1.000
0.995 0.995 CR
0.990 0.990
2000 2010 2020 2030 2040 2050 2000 2010 2020 2030 2040 2050
Years Years
 CSI discriminates the scenarios.
 CTI discriminates CR versus GL-DS-HQE scenarios.
Trends to go back to the baseline value around 2030-2040.

10. Discussion
Economic incentives can be an adequate driver for bird
biodiversity.
• Growth of 60% of FBI with HQE scenarios .
 Their use by the Common Agricultural Policy is relevant.
• Indicators tend to go back to the baseline value at the end of the projections.
 Completely suppress the incentives is not sustainable.
• Contrasted evolutions during 20-30 years in spite of already decreasing
incentives.
 Incentives can be slighty decreased, which leads to a budget
relocation to other environmental options.

11. Discussion
Contrasted populations among the scenarios.
Size Indicators Rich. Sp. Structure Indicators
FBI GBI Sh. CTI CSI
CR - - - - +
HQE + + + + -
• CR scenario  Little and weak diversified community with many very
specialized granivorous species.
• HQE scenario  Large and diversified community with granivorous –
insectivorous – carnivorous species.

12. Discussion
Combine FBI, CSI and CTI to evaluate the public policies.
• FBI more sensitive than GBI.
 Community size measured through the FBI.
• CSI discriminates CR vs GL vs DS vs HQE scenarios. But high CSI is not
always associated to a diversified community.
 CSI is relevant in mixed or grassland landscapes.
• CTI discriminates GL, DS, HQE, vs CR scenarios.
 CTI is relevant in openfield landscapes.

13. Thanks
More details in:
Mouysset L., Doyen L., Jiguet F. 2011. Different policy scenario to promote
various targets of biodiversity, Ecological Indicators, In press.
Lauriane Mouysset
mouysset@mnhn.fr
Fundings 2009-2012, FarmBird project, « Coviability models of FARMing and BIRD biodiversity »