Ludivine Lopez

Jérôme Montnach
email: jerome.montnach@univ-nantes.fr

Barbara Oliveira-Mendes

Baptiste Thomas

Cécile Caumes

Sébastien Nicolas

Denis Servent

Charles Cohen

Rémy Béroud

Evelyne Benoit

Rémy Beroud

Michel De Waard

Synthetic analogues of huwentoxin-IV spider peptide with

Keywords: huwentoxin-IV, selectivity, sodium channel

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.

  Toxines: Mr Hyde ou Dr Jekyll? -Toxins: Mr Hyde or Dr Jekyll? 27 èmes Rencontres en Toxinologie -27 th Meeting on Toxinology -e-RT27 (Rencontres virtuelles -Virtual Meeting) 9-10 décembre 2021 -December 9-10, 2021 50 Session "Animal toxins" Poster Synthetic analogues of huwentoxin-IV spider peptide with altered human NaV1.7/NaV1.6 selectivity ratios


Rémi Prudhomme
email: prudhomme@centre-cired.fr

Adriana De Palma

Patrice Dumas

Ricardo Gonzalez

Paul Leadley

Harold Levrel

Andy Purvis

Thierry Brunelle

G Kriegler

E Van Vuuren

D P Van Den Berg

M Feng

Calvin K Doelman

Havlik P Hilaire

B W Griscom

L L Gonzalez

Pynegar E L Robinson A N K Sanchez-Ortiz

E Caton

Newbold T, Contu S, Hill S L L, Lysenko I Hudson L N

Jung M Kemp

Adum G B, Aguilar-Barquero

Albertos B Alcala

Alguacil M Del M

Armbrecht I Arroyo-Rodríguez

Bhatt D Bicknell

Hurtt G C, Chini L P, Frolking S, Betts R A, Feddema J Fischer

Leandro Buendia

Barker B, Brooks T M S M Jantz

Le Quéré

Marland G Bopp

Hull V, Batistella M, DeFries R, Dietz T, Fu F, Hertel J Liu

J C Minx

Fuss S, Hilaire J, Creutzig F M W Callaghan

Thorben Amann

Khanna T Lenzi

Nemet Gunnar Luderer

Cantele M Liu

Combining mitigation strategies to increase co-benefits for biodiversity and food security

Keywords: Mitigation, Global scale, Land-use, Trade-off, Dietary change, Reforestation, Bioenergy, Food security, Biodiversity

come

Introduction

Land is a multi-purpose asset that may involve conflicts in its use. Formerly restricted to the local level, conflicts have become increasingly global over the last few decades because of the rapid intensification of international exchanges (Liu et al 2013). Currently, the joint challenges of global food security, climate change mitigation and conservation of biodiversity give a new dimension to this issue, involving new types of tradeoffs and synergies while strengthening the global dimension.

Assessments based on global land-use models have shown that mitigation policies relying on large-scale second-generation biofuel production have important environmental implications and, especially if forest protection measures are implemented, adversely impact food prices (Popp et al 2011, Humpenöder et al 2018, Heck et al 2018a). Afforestation is also associated with significant increase in food prices (Kreidenweis et al 2016) whereas dietary change policies may have the opposite effect (Stevanović et al 2017). Combining measures appears to be an appropriate solution to minimize negative effects, but the nature of the combinations promotes either biodiversity or food security (Humpenöder et al 2018[START_REF] Wollenberg | Reducing emissions from agriculture to meet the 2 °C target Global Change[END_REF], Visconti et al 2016).

Trade-offs between biodiversity and climate mitigation needed to be considered. While some mitigation policies such as carbon storage in forests can maintain biodiversity (Watson et al 2018), other options could increase pressure on biodiversity. Strong climate change mitigation scenarios relying on bioenergy are typically harmful to biodiversity either due to land-use change related to second-generation biofuel production (Hill et al 2018, Newbold 2018, Shukla et al 2019) or due to increased wood harvest for fuel in biodiversity hotspots (Jantz et al 2015). However, scenarios without strong climate mitigation are also associated with high impacts of climate change on biodiversity, especially in the second part of the century (Newbold 2018).

Combining on a global scale a model of agricultural intensification with a statistical model of biodiversity provides a unique framework for understanding (i) the impact of different GHG mitigation policies (secondgeneration biofuel production, dietary change and reforestation of pastures) on both biodiversity and food security and (ii) the degree of conflict or synergy between such policies.

Method

Overview of the modelling framework

The food system is represented by the Nexus Land-Use (NLU) model (Souty et al 2012). This global model of agricultural intensification describes the worldwide land-use system, computes cost-optimal food security indicators (average cost of production per calorie produced and food price per calorie produced), calculates associated agricultural and land-use change with respect to GHG emission goals and generates landuse maps (Souty et al 2012).

These land-use maps are converted into impacts on biodiversity through global estimation of two indicators of local biodiversity -Biodiversity Intactness Index (BII) (De Palma et al 2019) and within-sample Species Richness (SR) -applying a mixed-effect modelling structure based on the PREDICTS database (Hudson et al 2017). BII indicates the average abundance of a large, diverse set of native species in a given area, relative to their abundance in a pristine reference condition (Scholes and Biggs 2005) (See the Method section). The SR reports the number of species, relative to the number expected in a natural system (Section 6 in supporting information). These two indicators can provide complementary insights as they address both the number of species and differences in the composition of ecological communities present in ecosystems (Section 6 in supporting information). To clarify the impacts of GHG mitigation policies on these indicators, we made some changes to the framework used in Hill et al 2018: represented grassy and woody second-generation biofuel as highly intensified perennials.

Using this framework, we assess the impact on biodiversity and food security of land-use-based mitigation scenarios that provide mitigation of 4.3 GtCO2,eq/year in 2100 (which is the AFOLU sector's share of the mitigation needed to limit global warming to 2° in 2100: [START_REF] Wollenberg | Reducing emissions from agriculture to meet the 2 °C target Global Change[END_REF]. This mitigation target is calculated based on a methodology detailed in supporting information Table 2. We set a common target for every scenario to make their impacts on biodiversity and food security comparable.

We infer from these scenarios whether the relationship between biodiversity and food security in the presence of mitigation policies is synergistic or antagonistic and how the policy mix influences this relationship.

To mitigate the 4.3 GtCO2,eq/year in 2100, we built scenarios that are combinations of second-generation biofuel production (between 0 and 112 EJ/year in 2100), dietary change (a convergence towards the consumption of 432 kcal/capita/day of animal products which is a reduction except in Africa for nutritional reasons) and reforesting pastures (between 0 and 31% of global pasture reforested). Each mitigation scenario A c c e p t e d M a n u s c r i p t is detailed in supporting information. The mitigation effort of each of these policies (second-generation biofuel production, dietary change and reforestation of pastures) is then defined as the percentage of each policy in total mitigated emissions (Section 7 in supporting information). To cover a broad range of scenarios and represent a uniform distribution of mitigation policies (second-generation biofuel, dietary change and reforestation), the scenarios are constructed according to a full factorial design (Section 8 and 9 in supporting information). The experimental design involves taking mitigation efforts ranging from 0 to 100% for each policy in 10% steps while keeping the sum of efforts equal to 100% (Section 8 in supporting information).

Finally, we detail the distribution of these impacts across 12 large regions of the world. In this study, the mitigation effort is unequally distributed among the regions and depends on the amount of pasture available to reforest, the current diet and the regional cost of second-generation biofuel production. To compare the impacts of these heterogeneous mitigation efforts between regions and with the global figures, we calculate the relative change in biodiversity and food security divided by the relative change in regional emissions (Section 6 in supporting information for details of these indicators). This downscaling highlights the influence of the regional context on the sensitivity of responses of both regional biodiversity and food security to mitigation policies.

Description of the NLU and PREDICTS models

Estimating agricultural production The global

Nexus Land-Use model (NLU) is used to represent the agricultural sector (see Souty et al 2012 for more details). It allows us to represent agricultural intensification and the distribution of cropland, pastures and forest at the global scale. Crop intensification is explicitly represented in NLU with a concave production function and fertilizer prices are computed from energy prices (Brunelle et al 2015). Two livestock systems are considered: a grass-based system and a mixed crop-livestock system.

Regional production cost is minimized under a supplyuse equilibrium with a simplified representation of international trade. Based on an interpretation of the Ricardian theory, the boundary between the mixed crop-livestock system and the grass-fed livestock system changes according to the equalization of rent. In the mixed crop-livestock system, cropland distribution is based on potential yield, with rent increasing with land quality. In this model forest area is exogenously defined by scenarios. A detail description of these elements is provided in section 1 in supporting information.

Estimating agricultural emissions.

Agricultural emissions are calculated by NLU using the IPCC Tier 1 method for production in the plant food sector and the IPCC Tier 2 method for the livestock sector (IPCC 2006). In the livestock sector, emissions from manure management (CH4 and N2O) and enteric fermentation (CH4) are computed. In the plant food sector, emissions from fertilization (N2O) and rice cultivation (CH4) are computed. Carbon dioxide (CO2) emissions are also computed for land-use changes (Le Quéré et al 2009) and for fossil fuel substituted by second-generation biofuel (detailed in the description of biofuel scenarios in supporting information).

Estimating biodiversity impacts.

Biodiversity impacts are estimated by the PREDICTS modelling framework (Purvis et al 2018) which considers land-use to be the main driver of biodiversity losses [START_REF] Díaz | Pervasive humandriven decline of life on Earth points to the need for transformative change[END_REF].

The statistical models linking biodiversity to drivers are underpinned by a large, global and taxonomically broad database of terrestrial ecological communities facing land-use pressures. Among the biodiversity models provided by the PREDICTS framework, we chose BII because of its use in the Planetary Boundaries framework and SR because of its wide use despite its known limitations. The species richness model (SR) is a mixed-effect model computing the number of species present in a given area. The total abundance model computes the sum of all individuals of all species present in the ecosystem. The compositional similarity model computes the percentage of individuals common to the studied ecosystem and the reference ecosystem for each grid of a 0.5° map. The abundance map was then multiplied by the compositional similarity map to produce the map of abundance-based BII (De Palma et al 2019) (Section 6 in supporting information). These three PREDICTS models include different levels of management (intensive, light or minimal) and different types of land cover (forest, pasture, rangeland, annual cropland, perennial cropland and urban zones).

2.2.4

Linking PREDICTS and NLU. In NLU, 60 land classes are defined in the reference year according to their potential yield. Different crop types are defined for each land-class: "Dynamic" crops and "other" crops (See supporting information).

In PREDICTS, three levels of intensification break down perennial crops, annual crops and nitrogen-fixing crops into a "minimal", "light" and "intense" use category.

NLU crop types are aggregated into a single category and then split into PREDICTS crops categories (perennial, annual and nitrogen-fixing crops) based on their relative proportion of the crop mix in the reference year.

For the reference year, a Generalized Additive Model (GAM) is computed to match the relative proportion of "minimal", "light" and "intense" cropland with the 60 NLU land classes (See supporting information, Fig. 7). A GAM is used to avoid making assumptions about the form of the relationship between the intensification in PREDICTS and the land classes of NLU and to avoid giving too much weight in the relationship to uncertain extreme values (Section 4 in supporting information).

Pastures in NLU mixed crop-livestock and pastoral production systems are aggregated into a single pasture category. In PREDICTS, pastures include rangeland, "light" and "intense" pastures. Among the aggregated pasture category of NLU, rangeland areas are defined on the basis of reference rangeland map (Hurtt et al 2011). For the remaining pastures, livestock density is defined on the basis of livestock density maps (Robinson et al 2014). In the reference year, a GAM is computed to match the relative proportion of "light" and "intense" pasture with livestock density maps (See supporting information, Fig. 8).

Baseline scenario. The population follows changes in the

Mitigation scenarios to achieve 2°C of global

warming in 2100. We combine three mitigation policies in mitigation scenarios to achieve 4.3 GtCO2,eq/year of mitigated emissions in 2100. 4.3 GtCO2,eq /year is the target for the AFOLU sector to achieve 2°C of global warming. We deduced this target by applying the share of mitigated emissions by the AFOLU sector in overall mitigated emissions between the RCP2.6 and the baseline 2030 [START_REF] Wollenberg | Reducing emissions from agriculture to meet the 2 °C target Global Change[END_REF] to mitigated emissions between the RCP2.6 and the baseline of the marker model IMAGE (Gidden et al 2019) in 2100 (See Table 2 in supporting information) .

To obtain a broad representation of the possible combinations between second-generation biofuel production, dietary change and reforestation, we use a full factorial design (see Fig. 11 in supporting information), which covers second-generation biofuel production ranging from 0 to 112 EJ, animal product consumption ranging from FAO trends (Alexandratos and Bruinsma 2012b) to a convergence towards 432 kcal/capita/year (see supporting information, Table 2), and pasture reforestation ranging from 0% to 31% (see supporting information, Table 3).

To achieve 4.3 GtCO2,eq/year of mitigated emissions by means of dietary change, we replace the consumption A c c e p t e d M a n u s c r i p t of animal products by plant products in the Agrimonde scenarios called AG1 (Paillard et al 2014). This leads to a convergence of the overall animal consumption towards 432 kcal/capita/day in all regions. The consumption of ruminant products obtained is 183 kcal/capita/year in 2050 for Brazil, Canada, Europe, USA, FSU, OECD Pacific and Rest of LAM, 91 kcal/capita/year in 2050 for India, Rest of Asia and China, 154 kcal/capita/year for Middle-East and 65 kcal/capita/year for Africa (Section 10.1 in supporting information). The rest of animal product consumption (in the 432 kcal/capita/day) is composed of monogastric and aquatic products (See supporting information, Table 2).

The reforestation scenario follows the same philosophy as the natural climate solutions reforestation scenario presented in (Griscom et al 2017) by reforesting pastures (Section 10.3 in supporting information). The 31 % of pastures reforested in the world corresponds to the reforestation of 186 Mha with a carbon sequestration of 23 tCO2/ha in global average (See Table 5 in supporting information). This reforestation area is in the lower range of afforestation potential in baseline (Intergovernmental Panel on Climate Change 2014) (See supporting information for more details about the regional distribution, Table 3).

The second-generation biofuel production of 112 EJ is coherent with the literature that agrees on a technical bioenergy potential of at least 100EJ (Edenhofer et al 2011, [START_REF] Creutzig | Bioenergy and climate change mitigation: an assessment[END_REF]. To limit the competition of the biofuel production with food, second-generation biofuels in the scenarios are deployed in the form of grassy crops in Europe and the USA, and in the form of woody crops in the rest of the world (Section 10.2 in supporting information).

Indicators of food security and biodiversity. We use four indicators to represent impacts of mitigation policies on biodiversity and food security:

-Global food price ($/Mkcal) (Section 6 in supporting information).

-Crop production cost per unit of food energy produced ($/Mkcal) (Section 6 in supporting information) -Species richness (Section 2.2.3 in the method section) -Biodiversity intactness index (BII) (Section 2.2.3 in the method section)

Results

The scatter of points representing the impacts of landbased mitigation scenarios is widely spread over the output space and has concave boundaries, indicating a moderate trade-off between biodiversity and food security for a greenhouse gas reduction objective compatible with 2 degrees of global warming (Fig. 1 and see supporting information for other indicators). A table presenting the values of the four indicators (calorie price, cost, BII and SR) for each scenario is provided in section 13 in the supporting information.

Scenarios with high second-generation biofuel production are located well inside the cloud of points. This shows that second-generation biofuel production is a less effective mitigation option for reconciling biodiversity and food security objectives than scenarios containing more reforestation or dietary change (Fig. 1 and see supporting information for other indicators). Moreover, scenarios with low levels of biodiversity (especially low SR) tend to be those including high levels of second-generation biofuel production (supporting information Fig. 17).

Mitigation scenarios focusing almost exclusively on dietary change or reforestation are either at the upper right hand or at the lower left hand of the cloud of points. This indicates that they perform well in relation to one indicator but have negative side-effects on at least one of the others (See Fig. 14 in supplementary information). The reforestation of large proportions of the world's pastures is positive for both biodiversity indicators but causes a sharp increase in food prices and food cost, thus threatening food security (supporting information Fig. 14). By contrast, scenarios with significant dietary changes are less positive in terms of biodiversity but have lower impacts on food prices and food production costs (Fig. 1 and supporting information Fig. 17). The cost of food production and the price of food vary in the same direction across mitigation strategies but with larger change in price (Section 11.1 of the SI for an explanation of the A c c e p t e d M a n u s c r i p t difference between response of food price and cost). The impacts of a dietary change on biodiversity vary according to the indicator under consideration with a reduction in BII (-0.7 % per Gt CO2,eq) and an increase in SR (+0.3% per Gt CO2,eq) compared to the baseline. A major dietary change leads to less intensification of livestock farming, which in NLU model results in an increase in the pasture area without any influence on forest area (Section 12.3 in supporting information). Grazing land has a high species richness but its ecological communities have little similarity with those found in natural environments, which explains why there is a low BII and high SR in a dietary change scenario.

[Insert Figure 1 here (See Figure section after the reference section)] Figure 1. Impacts of mitigation scenarios achieving 4.3 GtCO2,eq/year of mitigated emissions in 2100 based on combinations of second-generation biofuel production, dietary change and reforestation. Outputs are presented as the relative change in biodiversity intactness index (BII) and food price in the climate mitigation scenarios with respect to the baseline (no mitigation policy). At the global scale, all climate mitigation scenarios reduce emissions by construction of baseline emissions (13.9 GtCO2,eq in 2100) by around 4.3 GtCO2,eq/year in 2100. Each climate mitigation scenario is coloured according to the dominant mitigation policy. The dominant emission reduction policy in each scenario is the one that contributes the most to emissions reductions. "Others" in the legend represents scenarios where no option accounts for more than 50% of the mitigation effort. The percent of mitigation policy is the share of mitigated emissions of the dominant mitigation policy (second-generation biofuel production, dietary change and reforestation). The food price and the BII in baseline in 2100 are also indicated.

[Insert Figure 2 here (See Figure section after the reference section)] Figure 2. Impacts of mitigation scenarios reaching 4.3 GtCO2,eq/year in 2100 of mitigated emissions based on combinations of second-generation biofuel production, dietary change and reforestation. Outputs are presented as the relative change in Species Richness (SR) and cost of food production in the climate mitigation scenarios with respect to the baseline (no mitigation policy). Each climate mitigation scenario is coloured according to the dominant mitigation policy. The dominant emission reduction policy in each scenario is the one that contributes the most of emissions reductions. "Others" in the legend represents scenarios where no option accounts for more than 50% of the mitigation effort. For additional details, see Fig. 1. The food production cost and the SR in baseline in 2100 are also indicated. Impacts of mitigation on other indicators are provided in section 12 in supporting information.

Portfolios of land-use-based mitigation scenarios reduce the trade-off between biodiversity and food security

On a global scale, mitigation scenarios that spread mitigation efforts between several policies (reforestation, second-generation biofuel production and dietary change) avoid extreme negative side effects. Among these scenarios involving different emission mitigation policies, some mitigation scenarios can improve both the protection of biodiversity and food security in 2100 compared to the baseline without mitigation policies (scenarios in the upper left-hand quadrant of the Fig. 1).

These mitigation scenarios are mainly mixes of reforestation and dietary change associated with low second-generation biofuel production. For example second-generation biofuel production of 10 EJ/year in 2100 (10% of the mitigation effort) associated with reforestation of 11 % of pasture (40% of the mitigation effort) and a low consumption of ruminant product of 150 kcal/capita/day (50% of the mitigation effort) decrease the food price by 13% compared to the baseline and increase BII by 1.2% for a decrease of 30% of emissions in the AFOLU sector compared to the baseline (Fig. 1).

Trade-off and synergies between food security and biodiversity conservation in mitigation policies at the regional scale

The trade-off between BII and food prices seen at a global scale is also found within some regions such as the region covering Japan, South Korea, Australia and New Zealand (OECD Pacific in Fig. 3), Europe, the USA and China, but differs in other regions because of the regional context. For example, food prices and BII are relatively insensitive to mitigation strategies in the former Soviet Union. In Canada and the Middle East, food prices, but not BII are very sensitive to mitigation A c c e p t e d M a n u s c r i p t strategies. Due to the small fraction of agricultural land in these regions (Hurtt et al 2011), their average regional levels of biodiversity are mainly influenced by the state of their natural areas and not by agricultural land-use changes (Fig. 3).

The choice of the optimal regional mitigation mix for BII and the food price varies from one region to another. On the one hand, large-scale bioenergy production systematically increases food prices and reduces biodiversity compared to a baseline without a mitigation strategy. On the other hand, the influence of reforestation and diet change in the mitigation strategy depends on the regional context. For example, a lower ruminant consumption decreases in the African dietary change (-46 kcal/capita/day) compared to the other regions (for example, -199 kcal/capita/day in Brazil in Table 2) leads to high levels of BII and a low food price (Fig. 3). For other regions like Brazil and the rest of Latin America, both dietary change and reforestation mitigation scenarios lead to higher price than the baseline without a mitigation strategy.

[Insert Figure 3 Figure 3. Regional impacts of mitigation scenarios reaching 4.3 GtCO2,eq/year in 2100 of mitigated emissions globally based on combinations of secondgeneration biofuel production, dietary change and reforestation. Outputs are presented as the relative change in biodiversity intactness index (BII) and food price in the climate mitigation scenarios with respect to the baseline (no mitigation policy). These indicators compare changes in relative BII and relative food prices by considering different amounts of regionally mitigated emissions indicated for each region by an average of mitigated emission in the different mitigation scenarios. These indicators are also provided at the global scale in Fig. 1. Similar graphs for other biodiversity and food security indicators are provided in supporting information

Discussion and conclusion

The major contribution of this study is that it is the first explore the full range of combinations of key landbased climate mitigation options -bioenergy, reforestation and dietary change -on biodiversity and food systems. The model projections are not predictions of future outcomes but do provide insight into the synergies and trade-offs among land-based mitigation measures, as well as their respective advantages and drawbacks. Another important novelty of this study is that it provides a global perspective of the impact of agricultural intensification and land use changes within the agricultural sector on biodiversity of both agricultural intensification and land use changes within the agricultural sector (conversion of the pastoral system into a mixed pasture-and-crop system), while previous studies have focused on the impact of mitigation scenarios on habitats of high ecological value such as "biodiversity hotspots" (Obersteiner et al 2016) or forests (Humpenöder et al 2018). Considering the impact of agricultural intensification on biodiversity provides several new insights. For example, the substantial agricultural intensification induced by a reforestation scenario mitigates the initial BII increase inside the reforested area. In addition, the reduction in extent of the crop-pasture mix system in favour of the pastoral system in scenarios of significant dietary change may lead to strong change in ecological community composition, as evidenced by the reduction in BII (Fig. 1). However, as the reforestation rates are exogenously set in NLU, the reduction in extent of the crop-pasture mix system is probably overestimated in this study, leading to an underestimation of the BII and the food price (Section 11 of the supporting information for a description of main mechanisms).

Another major contribution of this study is an understanding of the impacts of different land-usebased mitigation scenarios on different biodiversity indicators: (i) the "naturalness" of ecosystems through the BII and (ii) the local "extirpation risk" through the BII and SR (Karp et al 2015). Although we do not estimate extinction rates in this study, the biodiversity indicators computed in our mitigation scenarios provide additional and consistent information to the extinction risk in global biodiversity hotspots already studied by, A c c e p t e d M a n u s c r i p t e.g., Obersteiner et al 2016. Reforestation scenarios are beneficial to these three indicators, second-generation biofuel is detrimental to these three indicators and decreasing pressure on land through dietary change has a beneficial effect on SR and biodiversity hotspot preservation but decreases BII due to an increase in the area of pasture.

The inclusion of the impacts of these policies on biodiversity is a first step towards a deeper integration of biodiversity into the socio-ecological system used in environmental assessment of mitigation options. The crucial role of biodiversity in food production is well established and its integration into land-use models can significantly change the relationship between biodiversity protection and food security (Commission on Genetic Resources for Food and Agriculture and Food and Agriculture Organization of the United Nations 2019).

A portfolio of mitigation strategies reduces side-effects on biodiversity and food security compared to siloed strategies and allows several SDGs to be achieved simultaneously (Humpenöder et al 2018[START_REF] Wollenberg | Reducing emissions from agriculture to meet the 2 °C target Global Change[END_REF], Bertram et al 2018, Minx et al 2018). For example, reforestation of 22% of pasture (70% of the mitigation effort) and a dietary change of 90 kcal/capita/day from ruminant toward plant consumption (30% of the mitigation effort) is the best scenario to minimize negative impacts on our measures of biodiversity, food security and mitigation in the agricultural sector at the global scale. The portfolio effect is explained in this scenario by the complementarity of mitigation policies. The synergy is particularly strong between dietary change and reforestation strategies, as this combination allows for land to be spared through a reduction in overall food production, meaning it can both store carbon and preserve biodiversity (Stevanović et al 2017[START_REF] Wollenberg | Reducing emissions from agriculture to meet the 2 °C target Global Change[END_REF], Ewers et al 2009). On the other hand, the increase in second-generation biofuel production reduces the positive synergies between food security and biodiversity conservation even with an optimistic assumption about the quantity of emissions reduced per unit of second-generation biofuel produced (Searchinger et al 2018).

In this study, mitigation effort is allocated between regions according to reforestation potential, biofuel prices and the difference between local diet and a reference diet, but without considering the equitability or mitigation cost of this distribution of the effort. The relationships between biodiversity and food security we report could change when these allocation criteria are considered. Moreover, the potential for mitigation of emissions, food insecurity and biodiversity loss in the AFOLU sector, although very high (Heck et al In this study, we show the importance of considering the regional context, which strongly nuances the global trade-offs between biodiversity protection and food security protection. This study should therefore be complemented by future work that take into account the regional context. More specifically, soil carbon sequestration (Lal 2004) in regions with degraded soils such as southern Europe, some parts of Asia and Africa, or increased Nitrogen Use Efficiency (NUE) [START_REF] Zhang | Managing nitrogen for sustainable development[END_REF], Bodirsky et al 2014) in regions with low NUE such as China or India. Other important dimensions could be added to our analysis. For instance, the nutritional qualities and health benefits of food diets could be also considered in relation to recent work on the topic; and more location-sensitive measures of biodiversity, such as extinction rates or extinction risk, could usefully be added.

Our study shows the importance of combining exploratory with target-seeking scenarios to include new objectives such as we have done here with biodiversity. This approach differs from many others used in climate scenarios that select the scenario with the lowest implementation cost regardless of preferences toward other objectives, as biodiversity conservation or food security. For example, the RCP2.6 scenario (Vuuren et al 2011), implying an important second-generation biofuel production (equivalent to 181 Ej) leads to relatively low food prices at the expense of low SR levels (See Table 3). In this scenario, the negative effect on biodiversity is mainly due to the significant production of second-generation biofuel (Hill A c c e p t e d M a n u s c r i p t et al 2018, Jantz et al 2015)). In contrast, our approach allows the assessment of a wide variety of combinations of mitigation policies and does not make implicit assumptions about preferences between biodiversity and food security.

  here (See Figure section after the reference section)].

  2018b, Tubiello et al 2015, Tilman et al 2017), may not be exploited due to equitability of the allocation of effort or high mitigation costs (Tilman et al 2017, van den Berg et al 2019, Markel et al 2018).

  A c c e p t e d M a n u s c r i p t A c c e p t e d M a n u s c r i p tRobinson T P, Wint G R W, Conchedda G, Boeckel T P V, Ercoli V, Palamara E, Cinardi G, D'Aietti L,Hay S I and Gilbert M 2014 Mapping the Global Distribution of Livestock PLOS ONE 9 e96084 Scholes R J and Biggs R 2005 A biodiversity intactness index Nature 434 45-9 Searchinger T D, Beringer T, Holtsmark B, Kammen D M, Lambin E F, Lucht W, Raven P and Ypersele J-P van 2018 Europe's renewable energy directive poised to harm global forests Nature Communications 9 3741 Shukla P R, Skeg J, Buendia E C, Masson-Delmotte V, Pörtner H-O, Roberts D C, Zhai P, Slade R, Connors S and van Diemen S 2019 Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems Souty F, Brunelle T, Dumas P, Dorin B, Ciais P, Crassous R, Müller C and Bondeau A 2012 The Nexus Land-Use model version 1.0, an approach articulating biophysical potentials and economic dynamics to model competition for land-use Geoscientific Model Development 1297-322

  Figure list:

  Shared Socio-economic Pathway (SSP2) (Riahi et al 2017). Food demand follows FAO projections (Alexandratos and Bruinsma 2012a) with a global mean food supply at the household level in 2100 of 2585 kcal/capita/day of vegetable products and 615 kcal/capita/day of animal products. International trade parameters are kept constant. Forest, which is exogenous to the model, follows current trends (Hurtt et al 2011) until 2050 and then stabilizes. Fertilizer prices are computed based on energy prices (Brunelle et al 2015) taken from the baseline of IMACLIM-R (Waisman et al 2012). This leads to a global average calorie price of 79$/Mkcal, a global average production cost of 43$/Mkcal, a 14% reduction of BII by land-use change occurring between 2001 and 2100 and a 15% reduction of species richness by land-use change occurring between 2001 and 2100 compared to the biodiversity levels in 2001.

Acknowledgements

This work was supported by a doctoral school ABIES grant (provided by AgroParistech). This article has also benefited from the support of the LabEx BASC (ANR-11-LABX-0034), the Long-term modelling chair for sustainable development (Ponts Paristech-Mines Paristech) funded by ADEME, Grt-Gaz, Schneider Electric, EDF, French Environment Ministry, the aid from the French state managed by the ANR under the "Investissements d'avenir" programme (ANR-16-CONV-0003) and the funding by the NERC (award NE/M014533/1).

Alexandratos N and Bruinsma J 2012a


Kermagoret Charlene
email: charlene.kemragoret@ifremer.fr

Levrel Harold

Carlier Antoine

The Impact and Compensation of Offshore Wind Farm Development: Analysing the Institutional Discourse from a French Case Study

Keywords: communities of practice, ecosystem services, compensatory measures, no-net-loss goal, arine renewable energy, offshore wind farm

In France, the public acceptability of marine renewable energies and their impacts on ecosystem services (ES) involves questions about compensation for stakeholders, who may perceive some of their activities and interests to be modified. This paper seeks to understand how impacts on ES are perceived by institutional stakeholders and what is expected in terms of compensation. It also seeks to identify the communities of practice affected. We focus our study on the planned offshore wind farm in the bay of Saint-Brieuc. Our results show that institutional discourse is heterogeneous, depending on sensitivities, interests, and who or what the stakeholders surveyed represent or defend. Stakeholders' discourse can be interpreted on various gradients of perception. Six distinct communities of practice have been identified, based on the impacts perceived by institutional stakeholders. Lastly, we show that the community of practice seems to be a proper level at which to study perceptions and assess the nonet-loss goal.

Introduction

As part of Europe, France is politically committed to several objectives relative to the reduction of greenhouse gases. Among them, it must ensure a rapid development of renewable energy exploitation (European Commission, 2008). The French government has chosen to exploit its maritime potential in developing marine renewable energy including offshore wind energy. In northern European countries, where these technologies are widely developed, the deployment of offshore wind farms has partly alleviated major environmental and societal problems resulting from onshore projects [START_REF] Still | Offshore wind at Blyth[END_REF][START_REF] Ladenburg | Attitude and acceptance of offshore wind farms-the influence of travel time and wind farm attributes[END_REF]. However, the first offshore installations were not readily accepted by local populations [START_REF] Firestone | Public opinion about large offshore wind power: Underlying factors[END_REF]. Even though these technologies form part of a sustainable development approach, they can also have an impact on ecosystems, other human activities, and landscapes [START_REF] Boehlert | Environmental and ecological effects of ocean renewable energy development: A current synthesis[END_REF]. [START_REF] Gill | Offshore renewable energy: ecological implications of generating electricity in the coastal zone[END_REF] highlights significant physical disturbance of the coastal ecology during the construction and operational phases of offshore wind farms. These modifications of the environment can produce conflicts among interest groups such as energy companies, the fishing sector, and pro-environment activists [START_REF] Attrill | Marine renewable energy: Potential benefits to biodiversity? An urgent call for research[END_REF][START_REF] Haggett | Understanding public responses to renewable energy[END_REF][START_REF] Château | Building a stakeholder's vision of an offshore wind-farm project: A group modeling approach[END_REF]. These technologies can also be viewed by local stakeholders as threatening the natural beauty of a site and some local residents would be ready to pay higher costs per kWh produced in order to keep a wind farm away from the coast (Ladenburg and Dubgaard, 2007;[START_REF] Wright | Disruption to place attachment and the protection of restorative environments: A wind energy case study[END_REF]. Thus, [START_REF] Kuehn | Social investigation of the reception of Horns Rev and Nysted offshore wind farms in the local communities[END_REF] shows from two case studies that opposition to offshore wind farms is mainly based on aesthetic concerns and suggests that time, adaptation and communication about the projects may contribute to a change of opponent attitudes.

In France, the call for tenders launched in 2011 and 2013 for the exploitation of offshore wind farms clearly mention compensation as a tool to overcome residual environmental concerns and social conflicts. This socio-environmental compensation has a overall goal of territorial equity and social acceptability of projects [START_REF] Gobert | Ethique environnementale, remédiation écologique et compensations territoriales[END_REF][START_REF] Gastineau | Compensating for environmental damages[END_REF]. From a theoretical point of view, compensation must satisfy the objective of "no net loss" and can be understood in terms of the ecosystem services (ES) provided by marine biodiversity. The concept of ES can be seen as a valuable frame of reference for assessing changes in the material and non-material determinants of human well-being resulting from offshore energy projects [START_REF] Gee | Cultural ecosystem services in the context of offshore wind farming: A case study from the west coast of Schleswig-Holstein[END_REF][START_REF] Busch | Conceptualizing the link between marine ecosystem services and human well-being: the case of offshore wind farming[END_REF]. To understand better how the concept can be used in a negotiation process, two main questions will be discussed in this paper:

(1) How are impacts on ES perceived by institutional stakeholders and what compensation is expected?

(2) How the perceptions expressed by institutional stakeholders may be used to identify the various communities of practice who each share a different understanding of the implications of renewable offshore energy? Our case study is the planned offshore wind farm in the bay of Saint-Brieuc, one of the four sites selected by the first French national tender process.

Conceptual background

Compensations

Socio-environmental compensation has a goal of optimal distribution of benefits within the territory to ensure both social and ecological fairness. On the one hand, it is based on a clear legal framework that imposes the "avoid, reduce, offset" guidelines for environmental damages (Cuperus et al., 1999). On the other hand, it comes from pragmatism of the developers who implement compensation for victims in order to increase the social acceptability of projects [START_REF] Gobert | Ethique environnementale, remédiation écologique et compensations territoriales[END_REF]. Thus, the socio-environmental compensation can take many forms such as monetary incentives, public goods or biodiversity offsets according to the objective. In a context of an offshore wind farm, compensation may be considered as ecological restoration actions that target impacted species or ecological habitats [START_REF] Cole | How much is enough?" Determining adequate levels of environmental compensation for wind power impacts using equivalency analysis: An illustrative and hypothetical case study of sea eagle impacts at the Smøla Wind Farm[END_REF]. On the other hand, compensation may be considered in monetary terms for some affected stakeholders like fishers and should be paid to individual or into a trust fund set up to benefit fishers collectively [START_REF] Gray | Offshore wind farms and commercial fisheries in the UK: A study in stakeholder consultation[END_REF].

Theoretically, compensations aim to achieve a no-net-loss balance of ES, which can be assessed using either an ecological frame of reference or one based on human well-being [START_REF] Mckenney | Policy development for biodiversity offsets: A review of offset frameworks[END_REF][START_REF] Dunford | The use of habitat equivalency analysis in natural resource damage assessment[END_REF] (Figure 1). Reality is mainly based on a negotiation process carried out upstream of the projects to estimate the values of losses and thus recognize and reallocate the negative externalities [START_REF] Gobert | Ethique environnementale, remédiation écologique et compensations territoriales[END_REF].

Ecosystem services

ES are generally defined as the benefits obtained from ecosystems, deriving from ecological processes and functions (MEA, 2005). Including these services in the planning process should help in taking into account the various ecological functions provided by biodiversity, and not only the economic resources produced. In short, the use of this concept aims to reconcile policies relative to biodiversity conservation with those relative to economic development. Thus, the ES concept quickly surpassed the academic community and was introduced into some regulatory frameworks, in particular through the principle of compensation (UICN, 2011). ES can be divided into several categories (MEA, 2005):

-Provisioning ES resulting from direct harvesting of ecosystem resources; -Regulating ES deriving from the regulating processes of ecological functions that humans benefit from; -Cultural ES contributing to the cultural, aesthetic, and psychological dimensions of well-being. -These three categories of service rely on different sources of values. In environmental economics, a distinction is made between use values and non-use values. Use values concern the market and non-market services that the environment provides to humans both directly (such as fish stocks for recreational or commercial fishing) and indirectly (tide protection, pest control, filtering functions). They also include the benefits derived from potential future use (option values). Non-use values are based on the mere existence of an environmental component, whether or not it is used, and also on certain ecological or landscape features that will be preserved for future generations (CAS, 2009;[START_REF] Turner | Economics of natural resources and the environment[END_REF]. Thus, the values attributed to these ES depend upon the stakeholders who benefit from the services [START_REF] Hein | Spatial scales, stakeholders and the valuation of ecosystem services[END_REF]. In the context of offshore wind farm, [START_REF] Mangi | The impact of offshore wind farms on marine Ecosystems: A review taking an ecosystem services perspective[END_REF] shows that the induced changes on ES concern all three categories of ES and that their evaluation requires the involvement of multiple stakeholders.

Stakeholder involvement: from institutional stakeholders to communities of practice

Stakeholders are defined by [START_REF] Freeman | Strategic management: A stakeholder approach[END_REF] as "any group or individual who can affect or is affected by the achievement of an organisation's purpose" and more specifically by [START_REF] Röling | Facilitating sustainable agriculture: Participatory learning and adaptive management in times of environmental uncertainty[END_REF] as "natural resource users and managers". Thus, the use of the concept of stakeholder is a relevant framework for understanding managerial decisionmaking by taking into account the heterogeneity between individuals. However the concept can be approached in different ways depending on interests, ways of perceiving problems, or opportunities relative to the subject under investigation. Not all stakeholders have the same stake or level of interest in the marine environment where issues are multiple [START_REF] Pomeroy | The engagement of stakeholders in the marine spatial planning process[END_REF]. This raises the question of how to identify the stakeholders in a specific situation and which stakeholders deserve or require attention [START_REF] Mitchell | Toward a theory of stakeholder identification and salience: Defining the principle of who and what really counts[END_REF]. A scheme of stakeholders' scales is proposed in Figure 2 including institutional stakeholders, communities of practice, and individuals.

Institutional stakeholders are defined here as those who represent or defend a sectorspecific interest. They depend on an organisation to fulfil their own goals, and the organisation depends on them in turn [START_REF] Scholes | Exploring corporate strategy[END_REF]. Organisations may be municipalities, associations, committees, counties, sports clubs, and so on. They are known to the population because they represent a specific sector. Institutional discourse, which is carried out by institutional stakeholders, has been identified as a category of talk and has been described as an example of strategic discourse [START_REF] Habermas | Reason and the Rationalization of Society, Volume 1 of The Theory of Communicative Action[END_REF]. It is power laden and goal-directed, based on the homogenisation and the standardisation of the individual stakeholders' discourses represented by the organisation.

Communities of practice (CoPs) offer more specific descriptions of perceptions than institutions. A CoP is defined as a group of people sharing language, experiences, and knowledge through involvement in a similar activity [START_REF] Arias | Boundary objects: Their role in articulating the task at hand and making information relevant to it[END_REF]. A CoP is created over time in the pursuit of a common goal and is characterised by strong social relationships [START_REF] Wenger | Communities of practice and social learning systems[END_REF]. It can be defined in various ways: by size, the geographical scale on which it is active, or its institutional position [START_REF] Wenger | Communities of practice: Learning, meaning, and identity[END_REF]. The interactions that practitioners sustain among themselves within each CoP also lead to common social representations about an object, an activity, an idea or an event such as an offshore wind farm [START_REF] Levrel | Biodiversité et développement durable: quels indicateurs? Doctoral thesis directed[END_REF][START_REF] Amin | Knowing in action: Beyond communities of practice[END_REF]. In this study, we assume that the concept of CoP is used to help us establish a clear link between stakeholders and ES categories. In fact, a CoP can be defined by a shared interest in the use of specific ES. For example, environmentalists are attentive to the assessment of regulating services while scuba divers focus on cultural services. Analysing these links can help us develop targeted information for communicating with various CoPs [START_REF] Levrel | Etude de faisabilité pour la réalisation d'un Millennium Ecosystem Assessment en France[END_REF].

The third group is that of the individual stakeholders. They can be defined as citizens who are interested in, involved in, or affected by some project, and can belong to one or more CoPs. Individual perceptions are more specific and detailed, but eliciting them requires more effort given the need to ensure that they address all the relevant issues in a truly representative way.

We assume that descriptions of perceptions will be more specific the closer we get to the individual level. However, field work carried out at the individual level is most difficult to achieve if the representativeness of existing perceptions is sought. In this study, we focus our attention on perceptions of institutional stakeholders as the important first step of an extensive study describing social representations of a planned offshore wind farm. The importance of focusing on institutional stakeholders firstly, is that they are easily identifiable in the territory and further, they have a relatively good knowledge of the project and an integrated vision, which leads to well-constructed perceptions. Through the institutional discourse, we also seek to identify the CoPs directly affected by the project as a first step towards a broader analysis of perceptions.

Materials and methods

Case study

The study was conducted in the bay of Saint-Brieuc, where an offshore wind farm is planned. The bay, on the French coast in the western Channel (Figure 3), has a coastline of 115 km, bordered to the west by the island of Bréhat and to the east by Cap Fréhel. There are 23 municipalities along the coast, Saint-Brieuc being the largest one with 50,000 inhabitants. The main economic activities are commercial fishing and tourism. Because of its history and economic dominance, commercial fishing in the bay of Saint-Brieuc is particularly important and diversified [START_REF] Augris | Atlas thématique de l'environnement marin en baie de Saint-Brieuc (Côtes-d'Armor)[END_REF]. Great scallop (Pecten maximus) is the main targeted commercial species and has a strong patrimonial value for the territory's population.

The bay of Saint-Brieuc is attractive for tourists owing to the presence of remarkable sites such as Bréhat island, Cap d'Erquy, and Cap Frehel, which provide a panoramic view, and a large diversity coastal landscapes in which sandy or muddy beaches alternate with rocky outcrops [START_REF] Bertin | État des lieux du patrimoine culturel maritime du golfe normand-breton[END_REF]. The bay of Saint-Brieuc is also a biodiversity hotspot, as demonstrated by the various regulatory frameworks applied to it. The Natural Reserve of the bay of Saint-Brieuc was created in 1998 to preserve the natural heritage, especially the avifauna and their habitats. A total of 1864 ha of the bay is listed as a Natura 2000 site (including 1034 ha of marine areas). Recently, the bay has also been included in a planned marine park. These management tools must contend with major regional issues, including invasive species, green algae proliferation and multiplication of human coastal activities, including marine renewable energy developments.

The planned offshore wind farm involves the deployment of 100 wind turbines, designed to generate 500 MW, spread over an area of 80 km² situated 16,2 km off the coast, with the investment of 2 billion Euros. It is to increase electricity production with the goal of generating 8% of total electricity consumption in Brittany.

Open-ended interviews

A range of local "institutional" stakeholders were identified in order to be sure of taking into account most of the major issues related to offshore wind farm deployment and thereby a maximum of society-nature interactions. Stakeholders interviewed included political figures, managers of natural areas, economic actors, heads of public organisations, recreational associations, commercial fishers, and industrial wind companies. In May and June 2012, 24 semi-structured interviews were conducted with institutional stakeholders (Table 1). Most of them have been easily identifiable because they are involved in the project and, as a consequence, they are often mentioned in press articles and during discussions with first stakeholders interviewed. Others who are less invested in the project have been incorporated into the sampling plan because we have identified them as potentially affected by the project. Discussions were organised around four points: (i) the degree of knowledge and involvement of the organisation in the planned offshore wind farm; (ii) the presence or absence of organised groups supporting specific interests or strategies relative to the wind farm; (iii) perceptions of impacts (positive and negative) of the wind farm; (iv) perceptions of the compensation that would be needed to balance the impacts. The length of the interviews varied from 90 to 120 minutes. Some key questions were used as a guideline in order to cover all the categories of potential impacted ES when the conversations did not range widely enough. These questions were open-ended, with the possibility of pursuing clues that came up during the interviews. Open-ended interviews have the advantage of allowing a great freedom of talk for respondents and to collect all the issues inherent to the object of study. However, this method does not allow a quantitative analysis of the results and does not identify the influence of social factors in discourses, thus the interpretation of the results must be carried out with caution. In this study, the transcribed interviews were analysed with the aims of describing issues related impacts and compensations about the planned offshore wind farm; identifying the main communities of practice affected by the project; and finding out how perceptions are shaped within each CoP. Answers related to potential impacts and compensations have been analysed and then characterised from the three categories of ES i.e. provisioning ES, regulating ES and cultural ES.

Results

Main perceived impacts on ES

Perceptions of impacts on ES are widely heterogeneous in the sample, depending on the sector-specific interest represented or defended by the institutional stakeholders. As requested, general perception takes into account the three categories of ES and covers a large number of society-nature interactions. The results are summarised in Table 2 and analyzed by class of ES to which they refer.

Perceived impacts on provisioning ES

The perceived impacts on ES concern two different provisioning services: provision of food through commercial fishing and provision of clean energy through wind exploitation. The former is widely perceived as being negatively impacted by the offshore wind farm during the deployment and exploitation phases. This opinion was shared by the majority of institutional stakeholders surveyed, except for managers of natural areas who highlighted the potential "reserve" effect, which may increase fish and shellfish stocks. However, it was also assumed that the offshore wind farm will be a source of clean energy for the local community and thus represents a positive impact with respect to provisioning ecosystem services.

Since commercial fishers were invited to participate from early on in the consultation phase of the project, they have a clear perception of the impact of the wind farm on their activity: (1) loss of exploitable area and problems of access, especially for trawling gear due to the size of the wind farm; (2) changes in water quality during the construction phase and its indirect effect on benthic habitats; (3) ecological impacts on exploitable resources during the operational phase; (4) navigational hazards and environmental implications linked to undersea cable installation. In order to minimise impacts on provisioning ES, the wind farm company negotiated early with professional fishers in order to adapt the project to suit them. While the final decision on the right to navigate through the wind farm will be made by the prefecture, many institutional actors expressed reservations about the real capacity of fishing boats to navigate and work around the turbines. "There will be no more boats on this still relatively young scallop bed." (Commercial fisher) "The operators are very removed from the reality on the ground and local constraints, there may be some surprises." (Political figure )   The positive impact on the provision of clean wind energy for electricity generation was mentioned in some interviews. The farm is supposed to overcome the energy dependence of Brittany on other regions (in particular because there are no nuclear plants in Brittany). This argument is sometimes counterbalanced with other impacts on the territory and its ecosystems, such as the modification of the landscape.

"The project would account for 17% of the energy autonomy of Brittany, it requires some compromises." (Political figure)

Perceived impacts on regulating ES

The perceived impacts on regulating ES vary depending on the geographical and the spatial level taken into consideration. Since the offshore wind farm is seen as a contributor to global climate regulation, the project is perceived quite favourably by environmentalists. They see it as a better alternative than the previously planned natural gas processing plant close to Saint-Brieuc which they opposed a few years ago. On the local geographic level, regulating ES seem to be threatened. However, the survey's results show that it is difficult to represent the nature and extent of the impacts because of the many scientific uncertainties involved. Most stakeholders agreed with the project leader's decision to use jacket foundations rather than gravity base foundations, with the assumption that the former will have a lower impact on ecosystems. Environmentalist stakeholders are waiting for the environmental impact assessment before commenting on the impact on regulating ES. Lastly, there are some misunderstandings regarding the installation of an industrial site near a natural site (marine Natura 2000).

The political and economic institutional stakeholders have a more optimistic perception of the impacts on regulating ES. Apart from temporary disturbances during the construction phase, no negative impacts are anticipated. The expected reef effect of turbines' foundations is viewed as a positive impact on the marine ecosystem, even though some concerns are voiced. "How are these new ecosystems going to evolve? Will there be changes in the species that are present?" (Political figure) 4.1.3. Perceived impacts on cultural ES Perceptions of predicted changes in the aesthetic character of the landscape of the bay of Saint-Brieuc seem to vary widely within the population surveyed.

"I do not know what to think about the visual impact; it is difficult to have a clear idea of it." (Commercial fisher) "If it's a matter of what the landscape looks like, we can get used to it." (Commercial fisher)

"The eye is naturally drawn to the turbines, even if we want to ignore them." (Economic actor) Photomontages made by the project leader have been presented to stakeholders during public meetings around the bay. The image of a "matchstick on the horizon" used to describe the appearance of a wind turbine came up several times, to argue that the visual impact would be almost insignificant. The tourism industry seems less concerned by the visual impact. The fact that the planned offshore wind farm may become an attraction was brought up. Managers of natural areas do not think that the project will attract more tourists, who come mainly for the diversity of natural landscapes in the bay of Saint-Brieuc. The stakeholders belonging to recreational associations do not expect any direct impact on their activities. While scuba divers seem to be interested in benefiting from the new hard sub-sea landscapes, which may attract more diverse fish assemblages, a decline in clubs attendance because of the feared visual impact.

Compensation expected by institutional stakeholders for the perceived impact on ES

Institutional discourse about expected compensations is restricted to stakeholders who perceived some negative impacts on ES (Table 2). Once again, it is very heterogeneous according to the stakeholder to which it refers. Institutional discourses also focus on different types of compensation.

Monetary incentives

An annual tax based on the electricity produced by offshore wind farms will be a source of 14,000 Euros per year per megawatt 1 . The definition of this tax has been designed partially on negotiations between stakeholders and the French government. For example, because of the nature and the intensity of the impacts on their activity, professional fishers managed to increase the part of the tax which would return to them. An agreement has also been concluded to ensure that these funds benefit exclusively the projects carried out by the departmental fisheries committees directly affected by the planned offshore wind farms. Five municipalities are eligible for this tax and a sixth has attempted to integrate the scope of the tax arguing the existence of an island off its territory. The hotel industry also made a request to receive some of this tax money so that it could use it to bring hotel facilities in the region up to code as needed. In the end this request was rejected. Except for those who are directly affected, most of the stakeholders are unaware of this tax.

In addition to the tax, which provides a financial return for local authorities and stakeholders, some specific compensatory measures have been planned to compensate for specific impacts. These compensatory measures take into account the loss of activity associated with the wind farm's construction and use. With respect to loss of activity, it seems that only fishers have been considered eligible to benefit from compensatory measures. All fishers will have to submit documents to prove the impact of the wind farm on their own production. The departmental fisheries committee, who is responsible for dividing the overall allocation among individual fishers, is already concerned about future administrative confusion in the process. No other institutional stakeholders have made claims to monetary incentives.

Accompanying measures

Accompanying measures consist in funding actions or public goods to support the development of impacted activities. Unlike compensatory measures, they are not assessed from a specific impact and their limitations seem quite fuzzy. They are bilaterally negotiated with key stakeholders. Most of the accompanying measures benefit commercial fishers, giving them short-term funding while they wait for the long-term funding from the tax revenue to start in 2018. Formal agreement has been reached on eight accompanying measures, five of which have been made public so far: creating a new position devoted to the "energy issue" in the departmental fisheries committee; funding for projects to control the invasive species slipper limpet (Crepidula fornicate), an invasive benthic species; installation of chilled tanks for lobsters; great scallop reseeding; and funding a scientific study of the reef effect of the wind turbine foundations. These actions have been desired for many years by the departmental fisheries committee that takes advantage of this financial opportunity to carry out their projects. Moreover, a 10-year commitment to finance equipment for sailing clubs was negotiated between the project leader and some representatives of recreational users.

While these measures are already negotiated, other institutional stakeholders hope the implementation of additional accompanying measures to support the territory development. For example, a political actor has claimed to represent the most affected municipalitybecause of impacts on landscape, ecological habitats, and fishing -in order to have the harbour chosen as the site of maintenance work on the wind farm and thus indirectly to gain 1 This fund will be used by the National Fund for Compensation of offshore wind energy, as follows: -50% of the amount will be given to the coastal towns where the turbines will be visible. To benefit from the fund, the maximum distance from the turbines is 12 nautical miles. -35% will be allocated to the National Fisheries Committee to fund projects promoting sustainable exploitation of fishery resources. -15% will finance projects contributing to the sustainable development of maritime activities. related jobs for the town. A recreational association would like to have some artificial reefs installed in the bay if that becomes possible.

Biodiversity offset

Ecological compensatory measures seem to be less definable, as potential ecological impacts of offshore wind farms remain difficult to assess. Then, compensatory measures will be based on the outcome of the Environmental Impact Assessment. The results of environmental studies will be publicly available very late in the offshore wind farm planning procedure, after a consultation process and a public debate. One danger is that environmental stakeholders will encounter constraints when they make claims against the planned offshore wind farm or seek to participate in designing compensatory measures. However, the fishing industry has negotiated some protocols for monitoring fish stocks; these negotiations have led to agreements in which wind farm operators agreed to follow the protocols and implement measures to offset impacts.

Definition of CoPs in terms of perceived impacts

Six CoPs which each share a different understanding of the implications of the planned offshore wind farm have been identified from the institutional discourse. Links between these CoPs and ecosystem services have been identified and compiled in Table 3.

(1) Scallop fishers are concerned about negative impacts of the offshore wind farm on the shellfish stock. Great scallop has high economic and social value in the bay of Saint-Brieuc. This is the oldest fishing activity here and the bay is closely associated with this species. Most of the fishers in the bay are involved in it. The fishery fleet employs about 400 people in the bay, based in the maritime districts of Paimpol, Saint-Brieuc, and Saint-Malo.

(2) Trawl fishers are affected by an additional impact related to the difficulty of manoeuvring among turbines. While a minimum distance between two turbines has been negotiated to allow fishing in the wind farm area, some of those surveyed believe that trawling will no longer be possible in the wind farm area. Trawl fishers thus perceive the planned offshore wind farm more negatively than other fishers. Trawling in the bay of Saint-Brieuc is a secondary fishing activity as a complement to scalloping, and concerns mainly fishers from the maritime district of Saint-Brieuc.

(3) Members of naturalist Non-Governmental Organisations (NGO) are in favour of renewable energy developments, but expressed reservations about the offshore wind farm's impact on ecosystem functioning at the local level. They do not feel strongly about the project but remain attentive to the progress of the environmental impact assessment. The naturalist NGOs are grouped into five associations with thousands of members, of whom only a minority is really active. They have in-depth knowledge of ornithology, mammalogy, and more generally the ecology of land and coastal systems.

(4) Six recognised associations for environmental protection are grouped into a collective movement opposing the planned offshore wind farm. Members of these environmental associations are perceived by other institutional stakeholders as focused on individual interests related to the landscape impact of the offshore wind farm. On their side, they claim a lack of information and consultation on the part of the operators, as well as poorly understood environmental impacts. This movement includes nearly a thousand people, mostly second-home owners on the east coast of the bay. It is now seen by the operators as the most likely source of litigation.

(5) Tourists do not constitute a formal movement, but they share some specific perceptions, which lead us to treat them as a CoP. They seem to be sensitive to the aesthetic aspect of the landscape. They are not really aware of impacts and compensation and do not feel well informed about the planned offshore wind farm. Hundreds of thousands of tourists visit the bay each year and are a major source of income for the local economy; it is thus important to take them into account in the future.

(6) Recreational users feel a concern with the planned offshore wind farm but find it difficult to understand the associated impacts. Organisations hosting recreational activities are poorly informed about it, but do not exclude the possibility of taking advantage of it to develop new activities. Recreational activities along the coast are numerous in the bay of Saint-Brieuc. Recreational users fall into three main subcategories:

(i) Recreational fishers include thousands of people in the bay of Saint-Brieuc, fishing from the shore or from boats. They target various species and are sometimes in conflict with commercial fishers. They do not expect any impacts, but would like to benefit from compensation such as artificial reef installations in the bay.

(ii) Sailing is popular in the bay. Ten water sport clubs offers trips around the bay and towards the Channel Islands. There is concern that there may be a loss of the "sense of freedom" associated with this activity.

(iii) Scuba divers benefit from the biodiversity of submarine life in Brittany. Several diving club excursions are available in the bay. Opinions vary with respect to the potential reef effect of wind turbines: it is perceived positively by some and negatively by others.

Discussion

The discourses offered by institutional stakeholders are extremely heterogeneous and depend on their sensitivities, interests, and who or what those surveyed represent or defend. The level of knowledge of the respondents is also an important factor, since it influences the perception of impacts and the compensation claims [START_REF] Arnold | A review of public attitudes towards marine issues within and beyond New Zealand[END_REF].

Initially, the selection of institutional stakeholders was aimed at covering all the potential impacts on ES of the planned offshore wind farm. The distribution of perceived impacts across the local population is now better understood (Table 2). Discourses can be differentiated in terms of the perceived cumulative impact (positive or negative)  Only positive effects, Economic actors (industrial wind companies and local economic actors) perceive no negative impact. These institutional stakeholders do not consider environmental impacts [START_REF] Gray | Offshore wind farms and commercial fisheries in the UK: A study in stakeholder consultation[END_REF]. The planned offshore wind farm is a stimulus to job creation and a source of profit for private companies both locally and nationally. The project is all the more acceptable in that it fits into a sustainable development strategy.

 Balance of positive and negative effects, Political figures make the link between local economic interests and environmental concerns. Their discourses are more moderate, balancing negative impacts (on fishing, landscape) and positive ones (on global climate regulation, electricity production).

 Major negative impacts, Other institutional stakeholders surveyed (local NGOs, commercial fishers, and recreational activity organisations) perceived major negative impacts on the various components of ecosystems.

The perception of negative impacts is the necessary criterion for claiming compensation. Three types of discourses of the right to compensation have been identified:

 Opportunistic discourse: "Others receive compensation, what about me?" No significant impact is perceived by these stakeholders, but the idea of benefiting from compensation is seen as normal. The amount of compensation perceived as due is assessed in reference to those already negotiated by other stakeholders with the wind farm operators. For example, recreational fishers belong in this category. They are poorly informed about the project because they are minimally involved in the consultation process. Their perceptions of the impacts on their activity are hazy, but they do not reject the idea of being compensated by the deployment of artificial reefs. This type of discourse is also adopted by a political figure who perceives no negative impact on the municipality but is trying to modify its boundaries to include the area to benefit from tax revenue.

 Non-sequitur discourse: "We have every kind of impact, we need jobs!" Some impacts are perceived and compensation is expected, but there is no link between the two things. The presence of impacts is used as an argument to obtain compensation. For example, one mayor demands jobs because she believes that her municipality is the most heavily impacted. Here the challenge is to calculate the allocation of compensation across municipalities by reference to the impacts the offshore wind farm has on each of them. Non-sequitur discourse is also used by the hotel industry, which has sought to take advantage of the tax revenue in order to bring their facilities up to code.

 Reasonable discourse: "No net loss" Here perceptions of impacts are accurate and planned compensation matches the expected impacts. Some of the compensation has already been negotiated with the project leader, commercial fishers are included in this group because of their early involvement in the consultation process. They now have an accurate understanding of the impacts of the wind farm on shellfish stocks. Compensatory measures can be directly calculated based on the impact on each fisher's catch. The accompanying measures should in part cover the loss of commercial activity during the construction phase and also repair of ecological damage (scallop reseeding, for example). These measures are rather loosely defined, as the outcome of bilateral negotiations, and may in the end result in overcompensation for the actual impacts. In this case, compensation is responsible for stakeholders' acceptance of the wind farm. While they were opposed to it initially, fishers now support it, conscious of the opportunities offered by compensation.

Institutional stakeholders' discourse of impact and compensation has enabled us to identify CoPs grouped around specific social representations associated with the planned offshore wind farm. The CoP approach seems to be an innovative way to address the maximum number of issues in combination. Some differences among the CoPs identified are not intuitive, for instance those between trawl fishers and scallop fishers. The size of the fishing gear used makes a difference and will produce different impacts for fishers. Also, the distinction between naturalist NGOs and associations for protection of the environment had not been recognised before these investigations. These organisations have the same status but support different interests. While naturalist NGOs defend the collective interest in conservation of biodiversity and habitats, environmental protection associations defend interests related to the environment at large and governance aspects of the project. While the interactions among stakeholders within each CoP are frequent, interactions between the two CoPs as a whole are almost non-existent. Finally, the distinction between types of recreational users is interesting. Those engaged in different activities will not be sensitive to the same elements of the environment, and may be concerned with different components of the bay's ecosystem: above the sea or under it, offshore or on land.

The results of this study lead us to reassess our initial theoretical concepts and the adequacy of the figure representing the no-net-loss goal (Figure 1). We propose to improve this figure to better understand the mechanisms underlying the principle of no net loss (Figure 4). ES losses represented by area A can be assessed in terms of each stakeholder's perceptions of impact and divided for each category of ES (A 1 , A 2 , A 3 ). ES gains associated with compensation B can be assessed on the basis of each subdivision in order to achieve the no-net-loss goal (B 1 , B 2 , B 3 ). However, since the institutional stakeholders represent or defend a variety of interests, the risk that some of the ES will be "double-counted" is substantial. For example, impacts on fishing affect both commercial fishers and political figures (Table 2). An approach in terms of CoPs seems to be a more robust way to establish no net loss. Since each CoP has a direct relation to a specific category of ES (provisioning, regulating, or cultural), applying the principle of no net loss in terms of ES categories seems to be appropriate.

The continuation of this study will focus directly on CoPs in order to record their perceptions of the impacts on ES produced by the planned offshore wind farm in the bay of Saint-Brieuc and their claims for compensation. As we had anticipated, the CoP level seems the most appropriate for establishing a useful link with ecosystem services. This next step will require a larger number of interviews to obtain a representativeness of existing perceptions, because it includes a greater number of stakeholders. The results will be used to explore the no-netloss principle at the CoP level.

Figures

Figure 1. Residual impact to be compensated for in order to achieve the no-net-loss goal (adapted from [START_REF] Quétier | Assessing ecological equivalence in biodiversity offset schemes: Key issues and solutions[END_REF]. In this diagram, ES loss created by wind farm deployment which couldn't be avoided or reduced is represented by area A. Compensations are implemented (area B) in order to maintain the initial level of ES (reference state). To achieve the no-net-loss goal, area A has to be equivalent to area B. . Residual impact to be compensated for in order to achieve the no-net-loss goal, Figure 1 enhanced (adapted from [START_REF] Quétier | Assessing ecological equivalence in biodiversity offset schemes: Key issues and solutions[END_REF]. To achieve the no-net-loss goal, area A n has to be equivalent to area B n .

Figure 2 .

 2 Figure 2. Vertical division of stakeholders in our study

Figure 4

 4 Figure4. Residual impact to be compensated for in order to achieve the no-net-loss goal, Figure1enhanced (adapted from[START_REF] Quétier | Assessing ecological equivalence in biodiversity offset schemes: Key issues and solutions[END_REF]. To achieve the no-net-loss goal, area A n has to be equivalent to area B n .

Acknowledgements

The authors would like to thank all the institutional stakeholders who took part in the survey for their time and contribution. The authors would also like to thank the Fondation de France for funding this research.

Institutional stakeholders interviewed

Location

Geographical scope of activity

Interests represented or defended

Political figures

Mayor

+

New cultural activities

Table 2. Qualitative analysis of institutional discourses about perceived impacts ("+": positive impact or benefit; "-": negative impact; "+/-": both negative and positive impacts; "0": no perceived impact)