The Ecological Offset on the BPL
HSL, a French Linear Railway
Infrastructure
tttANNE INSERT NEW COVER IMAGE PLEASE________________________________________________

Eiffage, France – A Case Study (2018)

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Publication Data
Title: The ecological offset on the BPL HSL, a French linear railway infrastructure – Eiffage, France - A Case Study(2018)
Key words: Mitigation hierarchy, Compensation, Biodiversity, Linear infrastructure, Railway, High-speed line,
BBOP standard
Authors: Clément Bourge, Marion Aubrat (Eiffage)Acknowledgements: We thank the following individuals for their comments and suggestions: Amrei von Hase,
Kerry ten Kate, Joachim Lémeri, Laure-Hélène Candelier and Halya Odolant. We’d also like to address a special
thank to Dervenn for their help concerning the data collection of the compensation.

About Eiffage
Eiffage is one of Europe's leading construction and concessions companies. The Group's business activities
include: construction, real estate and urban development, civil engineering, metal, roads, energy andconcessions.
Unique by nature, universal by vocation, Eiffage is based on a structural balance between the Construction andConcessions businesses. Its multiple areas of expertise allow it to propose innovative solutions and to fund,design, construct, operate and maintain buildings, sites and infrastructures in France and throughout the world.
Thanks to the experience of more than 65,000 employees, Eiffage generated €15 billion in 2017, 21% of whichcame from other countries.
The Eiffage Group joined the Business and Biodiversity Offsets Programme (BBOP) in 2013.
Available from https://www.eiffage.com/en/home
See also http://www.developpementdurable.eiffage.com/en/

About the project
The Bretagne-Pays de La Loire High Speed Rail Line (BPL HSL) is a 182 km high speed railway junction between Le
Mans and Rennes situated in the west of France. It is the Eiffage Group’s most extensive project. Eiffage was
entrusted with the final design, construction and maintenance of the railway in 2011 and until 2036 is engaged
in a public-private partnership agreement with the SNCF Réseau (formerly the RFF), which manages the Frenchrail network.
Available from http://www.ere-lgv-bpl.com/home

The Ecological Offset on the BPL HSL, a French Linear Railway Infrastructure. Eiffage, France – A
Case Study (2018)
Business and Biodiversity Offsets Programme (BBOP). 2018.
BBOP, Washington, D.C.
© Forest Trends – Eiffage 2018.
Reproduction of this publication for educational or other non-commercial purposes is authorised without prior written
permission from the copyright holder provided the source is fully acknowledged.
Reproduction of this publication for resale or other commercial purposes is prohibited without prior written
permission from the copyright holder.
Cover and graphic design by Rima Design and Forest Trends
Photos by ©Gaël Arnaud and ©Dervenn
Date of publication: November 2018

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Abstract
The Bretagne-Pays de la Loire (BPL) high-speed railway line’s application of the mitigation hierarchy,
including biodiversity offsets, has benefitted from almost 20 years of planning, assessment and optimisationof mitigation measures to limit impacts on biodiversity. The project’s aim was to follow best practice andgoes beyond the requirements in the 2012 French regulation (Mitigation Doctrine, 2012).
This case study explains and demonstrates the project’s key avoidance, minimisation and compensation
measures. In particular, the case study details the predicted residual impacts and associated compensation
requirements for all species and habitat types listed in relevant water and protected species legislation. It
also sets out the kinds of compensation measures being implemented, where and how they are taking placeand how monitoring is undertaken.
The outcome of an assessment of the BPL project relative to the 10 BBOP principles is summarized. This work
was done to see whether the project could meet international standards for No Net Loss and identify lessons
learnt and areas for improving mitigation practice in future Eiffage projects in France and internationally.

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Table of Contents

PUBLICATION DATA ....................................................................................................................................................................... 2
ABOUT EIFFAGE .............................................................................................................................................................................. 2
ABOUT THE PROJECT .................................................................................................................................................................... 2
ABSTRACT......................................................................................................................................................................................... 4
TABLE OF CONTENTS ...................................................................................................................................................................... 5
TABLE OF ILLUSTRATIONS ............................................................................................................................................................. 7
TABLE OF ACRONYMS .................................................................................................................................................................... 8
INTRODUCTION ............................................................................................................................................................................ 10
1. THE FIRST STEPS OF THE APPLICATION OF THE MITIGATION HIERARCHY TO THE BPL PROJECT : AVOIDANCEAND MINIMIZATION ................................................................................................................................................................... 14
1.1

Early stages avoidance ............................................................................................................................. 14

1.2

To know the potential impacts of the project on biodiversity is to mitigate them better ......................... 16

1.3

Ecological continuities analysis and the establishment of the Key Biodiversity Components (KBC) .......... 16

1.4

Detailed studies ....................................................................................................................................... 17

1.5

Avoidance: The choice of a path of least impact ....................................................................................... 18

1.6

Minimization ............................................................................................................................................ 18

1.7
Residual impact and offset requirement assessment ............................................................................... 19
1.7.1 For protected species .................................................................................................................................. 19
1.7.2 For protected areas ..................................................................................................................................... 21
2.

THE OFFSET REQUIREMENT ............................................................................................................................................. 23

2.1

General principles .................................................................................................................................... 23

2.2

Risks that the residual impacts cannot be offset ...................................................................................... 24

2.3

Offset measures ....................................................................................................................................... 24

2.4
Offset on-site intensification .................................................................................................................... 24
2.4.1 Fungibility concept: intensive compensation over land consumption ........................................................ 25
2.4.2 Biological complementarities ...................................................................................................................... 26
2.5

Site selection ............................................................................................................................................ 27

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2.5.1
2.5.2
2.5.3

Anticipation ................................................................................................................................................. 27
Land securing strategy................................................................................................................................. 27
Sites secured ............................................................................................................................................... 29

3.

OFFSET IMPLEMENTATION AND SURVEY...................................................................................................................... 31

3.1

PAOG (development, orientation and management plan)........................................................................ 31

3.2

Offset works ............................................................................................................................................. 31

3.3

Effective implementation of the offset requirement ................................................................................ 32

3.4

Long-term management ........................................................................................................................... 33

4.

ANALYSIS OF THE PROJECT WITHIN THE BBOP STANDARD ...................................................................................... 35

4.1

The offset design ...................................................................................................................................... 35

4.2

The offset implementation ....................................................................................................................... 41

CONCLUSION ................................................................................................................................................................................ 44
APPENDIX 0: DETAILED DATA FOR ALL IMPACTED SPECIES AND HABITATS .................................................................... 46
APPENDIX 1: SYNTHESIS OF THE CONCLUSIONS OF THE ENVIRONMENTAL IMPACT ASSESSMENT (EIA) ................. 81
APPENDIX 2: DESCRIPTION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON BIRDS ....................................... 85
APPENDIX 3: DETERMINATION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON BATS FOR RESIDUAL IMPACT
ESTIMATION ................................................................................................................................................................................. 87
APPENDIX 4: DETERMINATION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON INSECTS FOR RESIDUAL
IMPACT ESTIMATION .................................................................................................................................................................. 88
APPENDIX 5: DETERMINATION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON SEMI-AQUATIC MAMMALSFOR RESIDUAL IMPACT ESTIMATION ...................................................................................................................................... 89
APPENDIX 6: DETERMINATION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON FISH FOR RESIDUAL IMPACT
ESTIMATION ................................................................................................................................................................................. 91
APPENDIX 7: DETERMINATION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON AMPHIBIANS FOR RESIDUAL
IMPACT ESTIMATION .................................................................................................................................................................. 92
APPENDIX 8: DETERMINATION OF THE PREDICTED DIRECT AND INDIRECT IMPACTS ON REPTILES FOR RESIDUAL
IMPACT ESTIMATION .................................................................................................................................................................. 94
APPENDIX 9: METHODOLOGY OF THE DESCRIPTION OF THE HEDGES .............................................................................. 95
APPENDIX 10: METHODOLOGY OF THE DESCRIPTION OF THE WETLANDS ...................................................................... 96
APPENDIX 11: METHODOLOGY OF THE DESCRIPTION OF THE PONDS AND WATER BODIES ....................................... 99
APPENDIX 12: INDICATORS OF THE POTENTIALLY IMPACTED WATER FLOW ZONES ..................................................102

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Table of illustrations

Figure 1: The Integration of the BPL HSL in the French high-speed railway ................................................................. 10
Figure 2: The route of the BPL HSL and key figures (Source: Eiffage) .......................................................................... 10
Figure 3: 2012, a key year for the BPL project .............................................................................................................. 12
Figure 4 : Examples of the route spindles families analysed (Source: EIA, SNCF Réseau) ............................................ 15
Figure 5: the BPL HSL and the large protected natural areas (Source: DREAL Bretagne and Pays de la Loire) ............ 16
Figure 6: Illustration of the concept and implementation of fungibility (Source: Eiffage) ........................................... 26
Figure 7: The Implementation process of ecological offset (Source: Eiffage) .............................................................. 29
Figure 8 : Location of the offset site (Source: Eiffage) ................................................................................................. 29
Figure 9 : Extract from a compensation site PAOG – BPL HSL (Source: ONF ; ERE) ...................................................... 31
Figure 10: Organization of the consortium of companies led by Dervenn (Source: ERE) ............................................. 32
Figure 11: Schedule of the follow-ups (Source: Dervenn) ............................................................................................ 33
Figure 12: Main offset measures occurrence (ha) (Source: Eiffage) ............................................................................. 48
Figure 13: Example of a provisional fence and awareness panel (Source: Eiffage) ...................................................... 49
Figure 14 : Pond and water body offsets (Source: Eiffage) ........................................................................................... 51
Figure 15: Offset ponds design principle (Source: Ecosphère) ..................................................................................... 52
Figure 16: Connection principle between landscape biological elements (Source: ONF) ............................................ 52
Figure 17: Hedgerows plantation principle (Source: Eiffage) ....................................................................................... 57
Figure 18: Artifical lodging for bats (Source: ERE) ........................................................................................................ 64
Figure 19: Hedges offset principle (Source: Ecosphère) .............................................................................................. 67
Figure 20: Distribution of the measures concerning the offset hedges (Source: Eiffage) ........................................... 67
Figure 21: Temporary sanitation (Eiffage patent: Modulap®) ...................................................................................... 72
Figure 22: Creation of habitats in the watercourses (Source: ONF) ............................................................................. 73
Figure 23: Transfer of the Soft hornwort (Source: Eiffage) .......................................................................................... 80
Figure 24: Transplantation of the Soft hornwort in an offset pond (Source: Eiffage) .................................................. 80

8Table of acronyms

BPL: Bretagne - Pays de la Loire
CIAF: Commission Intercommunale d'Aménagement Foncier / Intercity Commissions for Land Development
CRPF: Centre Régional de la Propriété Forestière / Regional Forest Property Centers
DPU: Declaration of Public Utility
EIA: Environmental Impact Assessment
ERE: Eiffage Rail Express (Eiffage’ subsidiary)
HSL: High-Speed Line
INRA: Institut National de Recherche Agronomique / French National Institute of Agronomic Research
KBC: Key Biodiversity Components
LOTI: Loi d’Orientation sur les Transports Intérieurs / Inland Transport Orientation Law
LPO: Ligue de Protection des Oiseaux / Birds Protection League
ONF: Office National des Forêts / National Forestry Office
PAOG: Plan d’Aménagement et d’Orientaiton de Gestion / Development, Orientation and Management Plan
RFF: Réseau Ferré de France / French rail network company
SAFER: Land Development and Rural Settlement Society
SDAGE: Schéma Directeur d’Aménagement et de Gestion des Eaux / Master Plan for Water Planning andManagement
SEPNB: Société pour l'Etude et la Protection de la Nature en Bretagne / Society for the Study and Protection of
Nature in Brittany
SNCF: Société Nationale des Convois Ferroviaires Français / French National Railway Company
SRCE: Schéma Régional de Cohérence Ecologique / Regional Ecological Coherence Scheme
ZNIEFF: Zone Naturelle d’Intérêt Ecologique, Faunistique et Floristique / Natural Areas of Fauna and Flora Interest

9I
Introduction

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Introduction
The Bretagne-Pays de la Loire (BPL HSL) is a new highspeed railway line that responds to the need for rapid
travel between the regions of Brittany, the Pays de la Loireand Paris, while serving the localities crossed (Figure 1 &Figure 2).
This new 182 km line between the cities of Le Mans andRennes was the Eiffage Group’s largest project. Eiffage
was entrusted with the final design, construction andmaintenance of the railway in a public-private partnershipagreement with the SNCF Réseau (formerly the RFF) that
ends in 2036.
Construction of the line took four (2012-2016) years but itis the result of 25 years of collaboration between the SNCF
Réseau, Eiffage Rail Express (ERE - an Eiffage subsidiary
dedicated to the project), authorities and local actors.
Figure 1: The Integration of the BPL HSL in the French high-speed railway
Network (Source: Eiffage)

Figure 2: The route of the BPL HSL and key figures (Source: Eiffage)11

A multi-criteria assesment was conducted, and iteratively refined until 2011, in order to choose a route with the least
amount of environmental, social and economic impacts, among others.
To design relevant measures for the territory, ERE consulted numerous stakeholders in the three departments
involved, namely: land planners, environmental studies offices, local associations for the protection of nature,chambers of agriculture and expropriation associations.
More than 80% of the environment concerned by the project is agricultural (farming and other types of husbandry).
The meadows are typically surrounded by networks of hedges (called “bocage”), apart from certain areas wheresome totally disappeared during a movement of land consolidation in the 1960’s. Natural protected areas likeforestation zones, groves and wetlands are also part of the region’s landscape. Forest density in these mostly rural
territories vary: very weak in the department of Ille et Vilaine, weak in the department of Mayenne with the exceptionof the periphery of Laval, intensifying sharply in the department of Sarthe.

Strong peri-urbanization, an important environmental issue
In 2007, French law clearly stated that mitigation hierarchy was to be adhered to in any project that impacted theenvironment. It was reaffirmed with the adoption of the Grenelle Law in 2009 and 2010.
French law has changed since the construction of the project, and along with the development of the notion of “No
Net Loss ” of biodiversity now strictly requires offset measures before the impacts appear (Biodiversity Law, Loi
Biodiversité, 2016).
As a showcase of the Eiffage Group's know-how in terms of sustainable development and turnkey projects, the BPL
HSL illustrates all of the stages of the mitigation hierarchy: avoidance, minimization, restoration of any temporary
impacts, compensation during the design, construction and maintenance phases of the project. Eiffage is committed
to preserving biodiversity in accordance with the (SNCF Réseau) National Strategy for Biodiversity (SNB) anddeveloped its own corporate commitment to the SNB and environmental charters for sustainable development,
biodiversity and water. The SNCF Réseau and Eiffage signed a specific sustainability agreement specific to the BPL
project that was beyond French regulatory obligations in 2013.
Adjustments of the right-of-way, works optimisations and technical adaptations are part of the measures enforced
to avoid and reduce the project’s impact on the environment. The Office Nationale des Forêts (ONF - National
Forestry Office), the principal natural areas manager in France, designed the compensation measures to offset theresidual impacts of the project with the objectives to respect the ecological equivalence principle, implement themeasures at an ecologically functional distance of the impacted sites, support the farming activities on offset sites
and implement the offset before the line was commissioned in July 2017.
Dervenn, a small Breton firm, executed the compensation works and to ensure the effectiveness of the measures will
also monitor them until 2036 (the date set by the local authorities and also that of the termination of the partnershipcontract). An observatory of the environment1 was also established to follow-up on the side effects of the line (e.g.,
possible cut-off effects of the line on amphibian displacements). These studies on the direct and indirect effects havebeen part of the observatory from the beginning and go beyond the legal requirements.

Evaluation of the project’s offset with ‘No Net Loss of Biodiversity’This case study describes how Eiffage and its partners approached and determined the expected impacts of the BPL
HSL (‘the project’) and how the design and mitigation measures were implemented in line with the mitigation
hierarchy. The purpose of the case study is to review the project with the 10 BBOP principles in order to assess the
BPL HSL in the light of international best practices. This will help us to:- better understand the internationally recognized mitigation standards in order to evaluate our practices
within this demanding standard;- experiment and share the complexities of applying of all of these standards on linear infrastructure projectsof this magnitude;- see how we can improve our project design and work organisation in order to improve our “weak” points.
1

http://www.ere-lgv-bpl.com/environnemental

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The ten Principles on Biodiversity Offsets were developed by members of the BBOP Advisory Group, who
support them and recommend them as the basis for the design and implementation of high-quality
biodiversity offsets. The Principles also provide the structure for the international Biodiversity Offset
Standard, released in 2012 by BBOP.
1. Adherence to the mitigation hierarchy
2. Limits to what can be offset
3. Landscape context
4. No net loss
5. Additional conservation outcomes
6. Stakeholder participation
7. Equity
8. Long-term outcomes
9. Transparency
10. Science and traditional knowledge

To go beyond complianceFirstly, it is important to note that the BPL HSL was designed to comply with French and EU laws and regulations andnot with the BBOP Standard. Aside from a few special circumstances, achieving the BBOP Standard of “No Net Lossof Biodiversity, and, where possible a Net Gain” was a goal but not required by French and EU laws and policies until
2016. Nonetheless, the standard is a key to how to manage impacts on biodiversity and was set as the BPL’s target.
Secondly, the BPL HSL project design had been underway since 1994, well before the BBOP Standard was publishedin 2012 (Figure 3). The detailed design was led in 2010 until 2012 by Eiffage and its engineering Setec. The assessmentof the project against the Standard was only undertaken in 2017-2018. Consequently, the aim of the assessment was
to appraise both the quality of the project’s mitigation measures and how closely they approach an outcome of ‘No
Net Loss’. The BPL HSL project has always aspired to not just comply with international best practices but to alignitself as closely as possible to them. This is the objective of this review.

Figure 3: 2012, a key year for the BPL project13

1

The first steps of the application of
the mitigation hierarchy to the BPL
project : Avoidance and minimization

14

1. The first steps of the application of the mitigation hierarchy to the BPL project :Avoidance and minimization
Hedgerows, well maintained in some sectors but generally more or less unstructured in others, largely separate thelands concerned by the project. The meshes of dense hedges enclose meadows and crops. The area crossed includes
small woodlots that rarely cover more than 50 ha, lakes, ponds and several valleys that shelter wet habitats.
Many of the small available offset sites were located in the surplus of the land reserves intended for the construction of theline. It was thus chosen to compensate by taking “Japanese steps”, (i.e., habitats close enough to each other to form an
ecological network/path for the species) on 240 sites along the 182 km of the HSL. This option was tricky because it required
managing many small sites across the territory as opposed to less larger sites, a practice more common for compensation. Oneof the advantages of this design was that these sites were included in the regional ecological corridors; measures implemented
in favour of green and blue corridors (hedges, grass strips, fallow fields, etc.) and serve as biodiversity reservoirs or relay sites.
The assumption made was that a multitude of sites would contribute to maintaining a certain ecological transparencyof the line. It permitted a wider distribution of habitats and species within the landscape rather than theirconcentration within it and could dilute the barrier effect caused by the railway line. With smaller distances to cross,the different species could move more readily from one plot to another.
Thanks to the securing of land ahead of time, 80% of the compensation sites are located within 2 km of the HSL rightof-way. Some offsets meant for forestation are among the 20% located further away. For example, concerning thehabitats of the chiropteran, closer proximity to the HSL of their forest habitats could have lead to excess mortality of
individuals seeking to cross the line.
The securing of land was carried out fairly quickly and as a result some of the offset works were begun in 2013, before
impact occurrence, and all of the works could be finished by 2016, before the line became active.
1.1

Early stages avoidance

The general avoidance approach is the result of early planning and iterative environmental and technical studies
mainly led by the SNCF Réseau, prior to the Declaration of Public Utility (DPU) in 2006.
The preliminary studies carried out from 1994 to 2001 made it possible to refine the definition of the project and to
avoid the most sensitive habitats and find the shortest and least expensive route in terms of earthworks.
In 1996, a set of spindles for the line’s route, grouped by “families”, was studied through a comparative analysis(Figure 4) including environmental impact assessments. The State services, elected representatives, socio-economic
actors and associations were consulted in 1999. The route was chosen based on the variant analyses, taking into
account the environmental stakes of the territory.
All of the studies commissioned by the SNCF Réseau formed the basis for the Declaration of Public Utility (DPU), which
included the Environmental Impact Assessment (EIA) of the refined route drawn by Egis Rail in 2006. A list of species
and sites of ecological interest (natural areas of fauna and flora interest (ZNIEFF), Natura 2000) was established, andthe potential impacts at a macroscopic scale (1000 to 1500 m from either side of the right of way) were assessed.
This first analysis made it possible to determine which groups of species could be potentially impacted by the project:amphibians, reptiles, bats, fish, insects, invertebrates, birds, wildlife; and to identify the potentially impacted
outstanding sites: ZNIEFFs and wetlands2.

2

Relatively to :- Directive 2008/32/EC of the European Parliament and of the Council of 11 March 2008 amending Directive
2000/60/EC establishing a framework for Community action in the field of water policy, as regards the implementing
powers conferred on the Commission- Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora- Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on the conservation ofwild birds

15

Route adjustments were again conducted at the end of thislarge-scale preliminary study in 2006, and Ecosphère conducteda more detailed environmental impact assessment (EIA) in
2011.
The DPU was declared on this EIA, which also formed the basis
for the drafting of the compensation chapter of the call for
tenders written by the SNCF Réseau.
The route thus avoids the main sectors with dense forests andhedgerows, usually areas that shelter a rich biodiversity. They
are identified as nodal areas, or reservoirs of biodiversity, andpreserve the main regional biological hotspots identified(Figure 5).
Some major environmental impacts were avoided because of
the choices made during the three major study phases, such as:
The regulated protected zones or areas ofscientific inventories: all regulated protection
perimeters for biodiversity were avoided: Natura
2000 sites, Sensitive Natural Spaces, Protected
Areas For Biodiversity, nature reserves, as well as
most of the ZNIEFF;
Some highly functional wetlands: the Fayelle pond
(ZNIEFF of type 1), thanks to the abandonment of
the northern passage of Vitré, and the "Bog of
Figure 4 : Examples of the route spindles families analysed(Source: EIA, SNCF Réseau)
Glatigné" (ZNIEFF of type 1) north of Laval;
Some wooded areas with high stakes: the Forest of
Pertre and the surrounding “bocage” areas south of Vitré; the Pincé Forest (ZNIEFF of type 2), and Grip
woods, thanks to the abandonment of the connection south of Sablé-sur-Sarthe to Angers;
A high-stake grassland: the Chopinière meadow in Précigné.

- Code de l'environnement, Livre II : Milieux physiques, Titre Ier : Eau et milieux aquatiques et marins , Article L210-1
and following + Livre IV : Patrimoine naturel, Titre Ier : Protection du patrimoine naturel and Titre III : Pêche en eau
douce et gestion des ressources piscicoles (Article L430-1) (French Code of the Environment)- Local master plans for water planning and management (SDAGE : Schéma directeur d’aménagement et de gestion
des eaux) for each watershed : Huisne (adopted in 10/2009), Sarthe Amont (adopted in 12/2011), Mayenne (adopted
in 06/2007), Oudon (adopted in 09/2003), Vilaine (adopted in 04/2003).

16

Figure 5: the BPL HSL and the large protected natural areas (Source: DREAL Bretagne and Pays de la Loire)At the time, the potential impacts within the DPU band were:
Number crossed
Area

1.2

ZNIEFFs of type 1
442.41 haZNIEFF of type 2
129.84 haTo know the potential impacts of the project on biodiversity is to mitigate them better

The detailed studies continued largely after the DPU with the SNCF Réseau’s updates of the environmental inventories
during the call for tenders (2009–2010) for the Partnership Contract and with ERE’s project optimizations that began
in 2011.
1.3

Ecological continuities analysis and the establishment of the Key Biodiversity Components(KBC)

In order to comply with French law, the SNCF Réseau had to make complementary assessments to the EIA becauseof a new requirement added in 2007, operational in 2010-2011: the ecological continuities (called “green and blue
corridors”). Several elements define these continuities in order to assess the impact of any project on them, of which,the landscape, the populations concerned, their ecological requirements and their mobility.
Ecosphère, an ecology-engineering firm, defined the key biodiversity components (KBC) in its assessment made in
2011. The KBC were defined according to the species’ sensitivity to fragmentation and their status of conservation ininternational, national, regional and local lists of threatened species (IUCN Red List of Threatened Species, endemic
species list3).
The most important habitats taken into account are: the hedgerows, the woods, the ponds and the bottomland
wetlands. Maintaining connections with other habitats such as crops, plantations, or surroundings around built-up
areas, were a more limited issue.
3

At the European, National and regional scales.

17

The criteria used to select the indicator groups are detailed in the following table:
Characteristics of the species

Risk to the species from fragmentation
Risk
Moderate
AverageOccurrence

Low
CommonIndividual home range

Little to medianMedianEcological niche

Large (non-specialist)

Narrow (specialist)

Mobility/dispersion ability

High

Moderate to highReproductive potential

High

Low

Population fluctuations

Low

High

High
Rare
Big
Low to moderate

A species was considered at risk with one high-risk characteristic out of the six. Different species of a same group
could thus be considered at risk causing the whole group to be treated as a KBC.
Few species or groups of species met the high-risk criteria in the sector affected by the BPL HSL. Intensive agriculture
practices and dispersed habitats had already fragmented the lands crossed by the HSL causing the species present on
the sites to more or less adapt to the situation; ecological functioning was also poor.
The following groups of species were considered at risk of fragmentation and thus selected as KBC.
Thus, five indicator groups were defined:
KBC

Indicator species

Bats

Species using the tree frame. High-flying
migratory species have been excluded

Semi-aquatic mammals
Nesting forest bird

Amphibians

Saproxylic beetles

1.4

Otter, Southwestern water vole, Neomys
Species with relatively strict requirements:
Black woodpecker and Middle spotted
woodpecker
All species potentially sensitive to the cutting
effect: common toad and natterjack toad,common parsley frog, common frog and agile
frog, European tree frog, newts and firesalamander.
Great Capricorn beetle and Hermit beetle

Habitats concerned
Hedgerows, forests and for certain species,
rivers, lakes, wetlands and associated habitats(buildings, bridges)
Large or medium sized rivers
Mainly old hardwood plantations relatively
high up
Mainly ponds, small lakes (less than 1 ha) andassociated habitats (more or less damp
meadows and woods)
Hedgerow system and forestation with old
trees

Detailed studies

Already aware of the main biodiversity issues of the project, Eiffage launched additional studies between Februaryand September 2011, before the Public Private Partnership (PPP) signature. These consisted of making naturalist
inventories, focused on the project’s footprint – comprising direct and indirect impacts – which were refined during
the call for tender in order to better estimate the impact of the project on the environment. The definition of these
impacts helped give a better estimate of the residual impacts of the project and propose avoidance and reduction
measures.
Experts were called upon to carry out the complementary studies for two reasons:- To know the environmental stakes precisely to be exemplary in face of the regulations related to thedestruction of protected species.
- To involve the associations and local design offices that master specific and localized subjects and that havebrought their respective know-how into this complex project.

18

Design consultancy
ASCONIT (wetland engineering consultants)

DERVENN

GREGE (Research and Study Group for theManagement of the Environment)
LPO (Birds Protection League - Sarthe
department)
Bretagne Vivante – SEPNB(Associations)
Mayenne Nature
Environnement
Centre Permanent d'Initiatives
pour l'Environnement, Vallées
de la Sarthe et du Loir
Conservatoire des Espaces
Naturels de la Sarthe
Hydrosphère (consulting firm specialized inwatercourses)

Service
Ecology of aquatic environments:- flows (Appendix 12)- wetlands (Appendix 10)- ponds and water bodies (Appendix 11)- flora- amphibians (in partnership with the ONF (French National Forest Office)(Appendix 7)- insects (Saproxylic insects, odonates, butterfly) (Appendix 4)- hedgerows (Appendix 9)- small terrestrial and semi-aquatic mammals (Appendix 5)- birds’ complementary inventory (Little Owl and Montagu's harrier) (Appendix
2)- collection of existing data on birds in the Sarthe (Communal scale)- bat inventories in Ille-et-Vilaine (Appendix 3)- collection of existing data on the fauna in the Sarthe- bat and bird inventories in the Mayenne (Appendixes 3 and 2)- collection of existing data on the fauna in the Mayenne (communal scale)- bat inventories in the Sarthe (Appendix 3)- collection of existing data other than birds (communal scale)- inventories of fish fauna from May to June 2011 (Appendix 6)This evaluation was key in determining the vulnerability of the inventoried species and the need to be offset. Whenavailable, information about the associated values was also given. A description of the direct and indirect impacts
was finalized in order to propose avoidance/reduction measures. The conclusions of these studies are detailed below
for each species.
1.5

Avoidance: The choice of a path of least impact

The SNCF Réseau and ERE detailed studies, once declared a public utility, allowed for environmental impact
avoidances since the beginning of 2011, through the project's optimizations by ERE:
By route shifting: for example, north of Laval (the commune of Louverné), the route was slightly shifted tothe south to avoid the southern end of the unique ZNIEFF impacted by the route of the DPU, the "Quarries
and Louverné lime kiln ";By changing the profile length: it has been optimized to limit the movement of land. When compared to theinitial project excess material was halved limiting the need for deposit areas;
By paying particular attention to the rights of way: The location of landscape models, permanent deposits,
water basins and ancillary equipment within the rights of way was studied in order to avoid areas ofenvironmental concern including floodplains and wetlands.
In addition, the technical rights of way have been optimized to avoid sensitive sites or stations as much as
possible. The number of ponds impacted by the project could thus be reduced by this detailed design work.
The impact on the 4 type 1 ZNIEFFs was thus avoided, and the impact on the only type 2 ZNIEFF was reduced (it stillpresented residual impact after the early stage avoidance).
1.6

Minimization

Reduction measures were sought and applied to reduce the residual impact of the project.
Without being exhaustive, the main measures are:
 Ecological transparency measures, including hydraulic ones, to preserve the functional connectivity of
species habitats: works to restoring transparency to the new infrastructure, but also to various plantations

19






and vegetation structures in order to enhance the attractiveness of a passage. Fences adapted to theecological stakes on both sides of the HSL were built in order to prevent intrusions and collisions.
Preservation of the ecological function of the natural habitats around the line, in particular the wetlands,
ponds, watercourses as well as the “bocage” fields (mainly networks of hedges), and the restoration ofwooded edges.
Ecological management and maintenance of green "dependencies" in the HSL's operating policy.
Targeted ecological engineering measures: the ecological development of riverbanks for certain insects
subservient to riparian environments, the creation of permanent artificial shelters for reptiles, thedevelopment of relay ponds for amphibians, etc.

The measures are detailed for each species and habitat concerned in the second part of this paper.
1.7

Residual impact and offset requirement assessment

The BPL HSL project is an ambitious one and despite all of the best efforts to avoid and reduce impacts on biodiversity,
there will be residual impacts on the natural habitats and on a certain number of species. Compensation measures
must be taken.
Thanks to the detailed studies it was possible to calculate the residual impact on each of the impacted species, interms of the surface of the habitat impacted, and for each protected area impacted (watercourses, wetlands andponds).
The offset requirement calculated was based on the residual impact and used expert-derived multipliers, which took
the following criteria into account:
1. The protection and conservation status of each species
2. The stakes of the territory crossed
3. The repartition and scarcity of the population of the species along the route of the project
4. Species sensitivity toward fragmentation
5. Ecological function of the impacted sites
The following two tables detail the residual impacts after the avoidance and reduction measures, the offset ratios
used, and the offset requirement for the species and protected areas. They are extracted from the appendix 0 that
explains their origin and justification.
1.7.1

For protected species
Species impacted

Residual impact

Offset ratio

Birds

Field crops

Offset ratio

Eurasian thick-knee

Burhinusoedicnemus
Montagu's harrier
Circus pygargus
Total
Bats
Bechstein's bat
Barbastelle

Myotis bechsteinii
Barbastellabarbastellus
Common long-eared Plecotus auritusbatWhiskered bat
Myotis mystacinus
485.15 hanc

13.81 ha91.14 hanc

Hedges, afforestation andecological corridors

Offset ratio

Offset requirement4
Plot withoutseeds
24 (72 ha)

Culturalconversion
25 ha

24 (72 ha)

25 ha
50 ha

Hedges, forestation andecological corridors

4.87 ha10.75 ha*4
*3

19.48 ha32.25 ha5.83 ha*2

11.66 ha17.46 ha*2

34.92 haStated in terms of what needs to be achieved, including mostly restoration interventions as well as some habitat
protection

20

Kuhl's pipistrelle
Natterer's bat
Serotine bat
Common pipistrelle

Pipistrellus kuhlii
Myotis nattereri
Eptesicus serotinus
Pipistrellus
pipistrellus
Total

11.97 ha5.49 ha
0.61 ha12.58 ha

*2
*2
*1
*1

23.94 ha10.98 ha0.61 ha12.58 ha22.7 ha(*2.7 average)

61 ha

Insects
Hermit beetle

Osmoderma
eremita
Cerambyx cerdo

Great capricorn
beetle

Total

Trees

Offset ratio

8 trees / 320 ml*8

153 trees
6120 lm*3

6440 lm/ 2322 lm

Tree requirements
2560 lm / 2,6ha
18360 lm /18.3 6966 lm / 7 ha
ha2322 lm

27 900 lm / 27,9 ha

Terrestrial and semi-aquatic mammals

Riparian buffer

Miller's water shrew Neomys anomalus

8.07 ha*3

24.21 haEurasian watershrew
Eurasian otter
European beaver

8.07 ha*2

16.14 ha3.75 ha1.44 ha8.07 ha*2*2

7.5 ha2.88 ha
25 ha

Neomys fodiens
Lutra lutra
Castor fiber
Total
Fish

Brown trout(spawning ground)

Spawning ground

Salmo trutta

Amphibians

Terrestrial
habitat

Bufo calamita

Common Toad
Edible Frog
Agile Frog

Bufo bufo
Pelophylax
esculentus
Rana dalmatina

107.6 haEuropean Tree Frog

Hyla arborea

23 haFire Salamander

Salamandra
salamandra
Triturus cristatus

Palmate Newt
Alpine Newt
Smooth Newt
Northern Crested
Newt
Common Midwife
Toad
Common Parsley
Frog

Offset ratio

214 lm /0.05 ha

Natterjack Toad

Northern Crested
Newt
Marbled Newt

Offset ratio

11.76 ha42.69 haTriturus
9.29 hamarmoratus
Lissotriton
helveticus
Ichthyosaura
alpestris
Lissotriton vulgaris*2

Number of
ponds

Pelodytes
punctatus
Total

137.95 ha

Spawning ground requirement
418 lm /0.1 ha

Offset ratio

3 / 1.17 ha*1 terr. habitat*5 ponds
27 *1 ponds
2 *1 ponds

Terrestrial
habitatrequirement
11.76

Ponds
requirement1527
230 / 5.42 ha *1 terr. habitat*1 ponds
12 / 0.2 ha *1 terr. habitat*3 ponds
14 *2 ponds

107.6

30

23

36

25 / 0.71 ha *1 terr. habitat*4 ponds
28 / 0.10 ha *1 terr. habitat*2 ponds
6 *5 ponds

42.69

100

9.29

56
30
48

9 *5 ponds

45

2 *4 ponds

8

8 / 0.31 ha

68 ponds

28

12 *4 ponds

Triturus cristatus
Alytes obstetricans 3.7 ha

Riparian buffer*1 terr. habitat*4 ponds
5 *4 ponds

3.7

32
20

137.95 ha

213 ponds

21

Flora
Soft Hornwort

Ponds

Ceratophyllum
submersum
Luronium natans

Floating WaterPlantain2 ponds /0.06 ha

Total

1.7.2

Offset ratio*2

Ponds requirement
4 ponds

2 ponds /0.06 ha

4

Ponds

For protected areas
Habitat impacted

Wetlands
Level 1/

Residual impact

Offset ratio

Offset requirement

70.46 haSee methodology
detailed inAppendix 10

140.92 haLevel 240.36 haLevel 393.23 ha46.615 ha

Level 450.39 ha12.59 ha254 ha240.5 haTotal

40.36 haPonds
Level 1

Fungible withamphibians
and flora

Level 2
Level 3Total

0.5 ha1.25 haSee methodology
detailed inAppendix 11

1 ha
1.25 ha2.4 ha1.2 ha4.2 ha / 110 ponds

3.45 ha

Watercourses
Waterway/

7200 lm*1 water act

7200 lm

Riparian forest

Fungible withfish
andaquatic
mammals

8.07 ha25 ha

Spawning ground

Fungiblefish

214 lm

*2
water
act
*2 (cuff fish offset)=
0.05ha*2*2.9(mammals
average)=
8.07ha*2.9
*2
water
act
*2 (cf fish offset)

with

428 lm22

2
The offset requirement

23

2. THE OFFSET REQUIREMENTThe Office Nationale des Forêts (ONF – the National Office of Forestry) was primarily in charge of the offset design. It
identified the potential offset sites, designed the first compensation “sketches”, and proposed management plansfor each of them in order to clear the ecological requirement.
The purpose of the compensatory measures is to compensate for the significant direct or indirect adverse effects ofthe project: They are implemented primarily near the sites impacted by the BPL project, to ensure their features in asustainable manner;
 They must make it possible to globally conserve, and when possible to improve, the environmental qualityof the environments;
 They must be carried out as quickly as possible, that is to say, for some of them before the implementationof the key works and for all of them, before the commissioning of the line. As the full efficiency of therestoration actions may take time, they must be effective as soon as possible: for this reason, land control,
already initiated on this project, was crucial.
Dervenn then adjusted the work by the ONF, in order to comply with farmers’ needs (see 3.1).

2.1

General principles

In order to remedy the residual impacts compensation aimed at an "in-kind" repair of them.
This approach is an analysis of the equivalence between the losses related to the impacts and the gains made by thecompensatory measures and to target and size the compensatory measures adapted to the residual impacts. Thisreading grid makes it possible to verify through monitoring and control that the compensatory measures respondwell to the objectives sought in the long term.
Different ecological criteria coupled with a dynamic spatial and temporal approach were used within the frameworkof the project. The notion of "equivalence", achieving a balance, or a significant gain at the relevant territorial scale
while taking into account the environmental recovery time was pursued.
Regulations provided some clarifications that were initially used as scoping elements : Thus, for the compensation of the "wetlands", both the circular of 24 December 1999 and the SDAGE
Loire Bretagne insist on the need to compensate for wetlands "equivalent in terms of function andbiodiversity", In accordance with Article L311-4 of the Forest Code, the administrative authority may authorize
clearing under one or more conditions; the Forest Code mentions the particular ranges of the areas tobe afforested in hectares, depending on the ecological or social quality of the woods targeted by theclearing;
 Finally, in the case of biodiversity compensation, the decrees of 4 January 2007 (amending theEnvironment Code - articles R.411-1 to 16) and 19 February 2007, amended by the decree of 28 May
2009, and the circular of 21 January 2008, define the procedures applicable to obtaining an exemption.
The ecological equivalence selected for the project embraces all components of biodiversity: theconservation of species and habitats as well as ecological features.

Thus, compensation for biodiversity was considered to be a transversal and structuring axis insofar as the proposedcompensation actions for biodiversity damage, and more particularly for the protected species, were aimed atmaintaining and even improving the conservation status of the habitats, species and functions of ecologicalcontinuities.

24

2.2

Risks that the residual impacts cannot be offset

This equivalency approach is an analysis of the equivalence between the losses related to the impacts and the gains
made by the compensatory measures. As the project progressed it became possible to verify that the foreseeable
residual impact could be compensated. The biological conditions of the populations of each species was analysed
and the risk of non-offset ability was assessed given the “good health” of the local/regional populations, the presenceof threatened or unthreatened species and the presence of sites favourable for compensation. Non-offset ability foreach of the impacted species, as for their habitats, was considered low on this project. The strong avoidance strategy
implemented before the project allowed for the low risk of non-offset ability (see 1.2.2).
After this verification, it was possible to target and size the compensatory measures adapted to the residual impacts
for each species and area impacted.
2.3

Offset measures

A biodiversity offset aims to address the residual impacts related to the project, to achieve no net loss and preferably
a net gain of biodiversity. With this objective in mind, the project established equivalency criteria between losses(induced by the project) and gains (provided through the offset measures). Equivalency has to target the same
components of biodiversity, qualitatively and quantitatively.
Offset measures can be:
1. Creation: the idea is to create a habitat that did not originally exist on a site. The creation of a habitat
may involve physical work (hydraulic, soil reconstitution) and biological techniques (ecological engineering,
re-vegetation, etc.).
2. Restoration and rehabilitation: the aim is to restore pre-existing habitats that have been destroyed, have
evolved or degenerated.
3. Preservation and enhancement, especially through management measures: these are actions aimed atensuring the preservation of environments that could be threatened without this intervention, (landpressure, changing context, uses and management modes, etc.).
All of the species impacted by the High Speed Line are compensated; offset measures are positioned after an analysisof the landscape and its functions (respect for the biotope, ecological connectivity and so on) and as often as possible
the offset is set near the impact. The challenge and objective are to avoid offset measures that are non-viable andthat are disconnected from the biological processes.
When the protected species are locally impacted in a limited way because of a large and stable population, the offset
measure efforts are concentrated on the more isolated sites to reinforce the more threatened populations.
The offset should be implemented before the occurrence of the impact in order to ensure the continuity of theenvironmental quality. This is why Eiffage chose to analyse the environmental stakes by having additional studies
made before signing the partnership agreement in July 2011.
It is important to remember that the offset measures aim at coherency with the land development plans of the local
communities.
2.4

Offset on-site intensification

Offset measures concerning the field of biodiversity are defined by various legal procedures: authorization is required
under the Environment Code (Code de l’Environnement), exemption requests for the destruction / movement ofprotected species also come under the Environment Code, and the authorization to clear is under the Forestry Code
(Code Forestier).
As mentioned above, the measures taken under these various procedures were considered and worked on by all
involved with a view of enhancing their convergences and complementarities, and thus obtaining the greatest
possible environmental benefits.

25

2.4.1

Fungibility concept: intensive compensation over land consumption

One of the peculiarities of this project is the nature of the land crossed: the line impacted many farms and it was difficult tosecure available land for the implementation of offset measures before the validation of land development (2014).
The basic principle that led to the adoption of fungibility follows. Actions that aim at a significant net gain, that improve thequality of the environment and contribute to the return to a favourable state will, in most cases, benefit a significant numberof species, almost always more than the number of species targeted (Figure 6). Given the specific linear nature of the project,
its impacts and compensation measures, this was an innovation.
Three regulations govern the ecological compensation actions in France. These are:
1.
2.
3.

the Forestry Act for land clearing and afforestation;
the Water Act, in terms of impacts on watercourses, groundwater and aquatic environments;
the Environment Code that prohibits the movement and destruction of protected species in the case of impacts
on biodiversity.

The BPL High Speed Line combined these regulations on impact compensation to create leverage in terms of achievement andultimately increase the ecological benefits of the proposed offset.
Indeed, whether they be technical measures such as the restoration, rehabilitation and preservation of the natural habitats,or measures of site conservation management in the medium and long term, the same ground compensation action responds
to different impacts: this is the principle of fungibility. The advantage of fungibility is that it does not outweigh spaceconsumption at the expense of other land uses, including agriculture. For example, the compensation schemes for thewetlands on the BPL High Speed Line were conceived in line with those of the breeding or resting habitats of amphibians. The
re-naturation of watercourses was thought out to jointly develop favourable habitats for certain protected species such as theSouthern Damselfly and to promote water supply in associated wetland areas.
Finally, the rate of fungibility achieved with this operation is about 25% between the woodlands compensated and thecompensated protected species, notably bats, as well as between the water component — wetlands — and protected species
compensation, especially for amphibians. The fungibility among these different measures was imperatively justified by theinterest it represented for the species concerned.
The BPL HSL is the first example in France to have such an intensive compensation scheme, fungibility measures, validated by
the competent authority. However, there is some international debate, for example in the USA and Australia, about whether
and when this type of 'fungibility' approach is appropriate and justified. It should be applied with caution5.

5

See von Hase, Amrei and Cassin, Jan. 2018. Theory and Practice of ‘Stacking’ and ‘Bundling’ Ecosystem Goods andServices: a Resource Paper. Business and Biodiversity Offsets Programme (BBOP). Forest Trends, 2018, Washington,
D.C.

26

Figure 6: Illustration of the concept and implementation of fungibility (Source: Eiffage)

2.4.2

Biological complementarities

In addition a “biological complementarities” approach was also implemented for offset design.
An initial analysis classified the "biological objects" (species and habitats) for which there was a residual impact
according to their presence in the major types of environment. The analyses of the residual impacts revealed thebiological complementarities and synergies between the biological objects’ properties, taking into account that they
could use some or all of the other types of environment.
It is therefore a question of identifying the biological objects that share their habitats with the greatest number ofothers and, when possible, show a high sensitivity evaluated in the light of the accumulation of the protection statuses
and rankings; and this for each of the selected types of environment.
The biological objects selected, as far as possible, are "umbrella species": the high level of their ecologicalrequirements allows for the presence of many other animal or plant species, from the most ordinary to the mostremarkable. In other words, the compensatory measures that maintain or favour the targeted species potentiallybenefit a wide range of species with which they share their habitat complementarities.
By preserving the connectivity of the environment, maintaining and restoring the habitats of these groups of umbrella
species, in the form of a network, also makes it possible to meet the goal of preserving the blue frame (ponds andwetlands) and the green frame (bog areas: meadows, hedgerows).
Three structuring analyses axes have been identified. The objective is to anticipate the best operational measures tobe implemented for the highest ecological benefits that can be reasonably expected:
1.
2.
3.

Amphibians dependent on three major types of environments: the wetlands for breeding grounds, forest andhedgerow environments for wintering and foraging environments.
Saproxylic insects (including Osmoderma eremita and Cerambyx cerdo), dependent on two main types ofenvironment: the horticultural environments and the forest environments.
Bats occupy various ecological niches for their habitats (hibernacula, mating grounds, transit lodgings, calving
grounds) and their hunting area.

This functional approach to the environment is an important point in the design and implementation of compensatory
measures. The structure of the methodology of the three axes does not exclude compensation actions for the benefitof other species: vegetation, bird life, bats, terrestrial and semi-aquatic mammals, fish fauna, reptiles, molluscs andinsects.

27

Further study expanded to integrate all of the other impacted species and habitats so as to determine morethoroughly which actions were to be undertaken with which appropriate monitoring methods.
The proposed compensatory measures involve:-

2.5

Technical measures of implementation: restoration / rehabilitation, preservation / enhancement of habitats,creation.
Management measures to ensure the conservation of habitats and species, as well as the sustainability ofthe technical actions performed.
Site selection

To obtain the equivalence between the losses caused by the impacts and the gains made by the compensatory
measures imply knowing and securing the offset sites early.
Three principles guided the search for sites eligible for compensation and to ensure the sustainability of themeasures:- Compensation as close as possible to the impact;- The identification of a pool of sites in excess of the compensation needs estimate: 1,900 ha were thus
pre-identified in 2011 in order to counteract the random nature of land negotiations;- For easier management, in the search for eligible offset sites priority was given near the line (in theright of way of the line, and secondly in the perimeter of land development). This land prospection was
fulfilled within very short deadlines.

2.5.1

Anticipation

To achieve compensation measures it was urgent to obtain the control of the necessary sites. As soon as thePartnership Agreement was signed in July 2011, discussions were initiated with the specialized parties such as land
operators, natural area managers and environmental associations. The land operators were commissioned as of 2011
to preempt land near the HSL right-of-way and to ensure that land control was compatible with these deadlines.
Indeed, these measures had to be fulfilled within a timetable compatible with the objective of avoiding any net
ecological loss. Thus, in the spring of 2012, a number of ponds were implanted for amphibians near the ponds thatwould soon be impacted by the works.
2.5.2

Land securing strategy

Securing land is essential for an efficient long-term implementation of offset measures. The legal compensation
duration requirement on this project is for 25 years (until 2036).
Whenever possible, compensation actions were established within the project boundaries that did not require landrelated acquisitions. When it was not possible, the securing of land sites and spaces was conducted through theacquisition and / or agreement with the owner / occupier and / or the site manager (Figure 7).
Numerous contacts with the local associations and managers, feedback from the consultation phases with the local
authorities and local residents constituted an important pool of useful resources.
To ensure securing land for the sites located within the perimeter of land development, land and forest geometers
and operators from the local General Councils were called in to identify the favourable plots.
Despite the sensitivity of the agricultural players to any new impact on land, the approach and the identification ofsites were positively received during the meetings conducted by ERE and the ONF in 2011:
with the Associations of Expropriates (ADE) of the 3 departments;

28

-

-

with the “chambers of agriculture” of the 3 departments;
with the land services of the 3 departments in charge of land development, and the land surveyors in chargeof their implementation;with the 3 SAFERs (Land Development and Rural Settlement Society) in charge of the land reserves;
with the Intercity Commissions for Land Development (CIAF) for land development sectors, with the ADE for
non-land development sectors;
with mayors and some residents.

In 2011, SAFER, a French real estate operator of public interest, was asked to purchase all the available properties
needed for the construction of the line and the associated land planning. 5 to 10% were acquired using their preemptive rights, the other through amicable negotiations. In 2011 the reserve represented 3,700 ha; over 2,000 ha
were destined for the HSL right-of-way.
An estimation of the quality of the land was conducted on the sites and the less fertile lands were proposed as
potential offset sites to the ONF, the operator mobilized by ERE.
The expertise of the ONF was called upon to confirm the interest of the pre-identified sites in view of thecompensation obligations and definitions of the potential measures. This analysis was made formal with a PAOG (adevelopment, orientation and management plan), whose content and format were validated in July 2012, after the
first meeting of the working group on compensation measures. The group was composed of the local authorities
concerned (DREAL, DDT (M)), the public institutions in charge of environmental policies (ONEMA, ONCFS), a nationaland regional scientific council and the client.
In 2013, in order to stay attractive to farmers and achieve the offset objectives, the SAFER services adjusted thechosen sites to the associated PAOG.
After that phase, in 2015, SAFER called out for farmers to apply to lease and manage a site for the symbolic sum of 1
euro, keeping in mind the recommendations of the PAOG.
Four specifications and various measures that regulate the agricultural practices authorized on the sites concerned
were defined in close collaboration between ERE, the agricultural profession, the departmental associations of the
expropriated (ADE), the State services and the National Forestry Office (ONF). The use of the sites by the operators
had to be compatible with the maintenance of the restored ecological functions and with a viable agricultural activity.
The sites mobilized for the implementation of the ecological compensation of the residual impacts of the HSL BPL arenot, for the most part, located on land of better agricultural quality (INRA, 2018).

29

More candidates responded than lands were available. The candidates were chosen according to their reliability andtheir interest in biodiversity.

Figure 7: The Implementation process of ecological offset (Source: Eiffage)

2.5.3

Sites secured

Because of anticipation 100% of the land was secured by early 2014, and all of the immediate compensation ponds(91) were implanted by 2012, before impact occurrence.
In total, compensation measures were implemented on 240 sites, representing 816 ha, mostly located in a 2 km bandaround the line (Figure 8). The mean area of the sites is 3 ha and the biggest is 20 ha.
Eiffage owns 80% of the sites, 95% of which are managed by farmers (115 rural environmental leases with local
farmers); Dervenn manages two sites.
The remaining 20% of the sites are under contract (90% in agricultural management and 10% directly managed by
Dervenn).
Because of this strategy agricultural activity was maintained on 94% of the number of compensation sites.

Offset sites
Figure 8 : Location of the offset site (Source: Eiffage)30

3Offset implementation and survey

31

3. OFFSET IMPLEMENTATION AND SURVEY
Offsetting of the impacts is a regulation that comes after the avoidance and minimization steps. Eiffage committed
to implementing this offset before the commissioning of the line in July 2017 and to managing the sites until 2036,
end date of the PPP contract. The implementation and surveying processes are detailed in the following paragraphs.
3.1

PAOG (development, orientation and management plan)

For each of the compensation sites, a development, orientation and management plan (PAOG, Figure 9) was set upby the ONF with the help of independent experts (ecology experts, agronomists) and in consultation with local
stakeholders (associations, chambers of agriculture, farmers, etc.).
This document detailed:
The initial state of the site: species present and nearby, characterization and localization of natural habitats
and wetlands;
Compensation actions to be implemented: location, nature, legislation ruling each action (water law,clearing, protected species exemption);Management constraints, periods and frequency of intervention.
These management plans are established to ensure the achievement of long-term compensation objectives.
3.2

Offset works

Figure 9 : Extract from a compensation site PAOG – BPL HSL (Source: ONF ; ERE)

In July 2014 ERE selected a consortium of companies to implement the compensatory measures (Figure 10) requiredby the construction of the BPL HSL.

32

They are: Dervenn (Figure 10Erreur ! Source du renvoi introuvable.) (works, studies and the conduct of ecologicalengineering projects), Cardin TP (Civil Engineering), Ouest 'Am (ecological design office) and Ter-Qualitechs(agronomist council).

Figure 10: Organization of the consortium of companies led by Dervenn (Source: ERE)

ERE decided to choose a single consortium for the implementation and survey of all the compensation measures, inorder to:- contribute to the coherence and synergy of the proposed measures- make them readable for the stakeholders of the territory- facilitate their implementation and their survey.
This choice of a single operator also benefits the local stakeholders of the territory, sought by Dervenn, for thedefinition, the operational implementation through the works, the plantation activities, the ecological engineeringand the long-term management of the compensatory measures.
A transparent report is annually provided to the administrations in charge of environmental policies so they canmonitor the concrete implementation of the measures and the on-site results.
100% of the compensatory measures were implemented by mid-2016, almost one year before the commissioning of
the line in July 2017.

3.3

Effective implementation of the offset requirement

The offset set up represented 920 hectares of compensation for the species and habitats impacted. This very large
area represents almost half of the HSL’s footprint.
The details of the offset and what has actually been implemented are in Appendix 0, species by species and habitatby habitat. This makes it possible to compare the requirements and the effective implementation of the measures,
leading to the following conclusions:

33

Item

Effective offset implemented
compared to the offset required

Bird habitats
Bat habitats
Insect habitats
Semi-aquatic mammal habitats
Fish habitats
Flora (habitats)
Wetlands
Ponds
Watercourses
Riparian linears
Spawning grounds

+ 3%
+ 25%
=
=
=
+ 200%
+ 3%
+ 29%
+ 67%
=
=

It is to note that the habitats offset for wetlands, ponds and watercourses are always qualitatively equivalent to theimpacted sites and usually present a higher ecological potential.
Consequently, these results allow us to consider that for these items the ecological equivalency principle wasrespected suggesting that a No Net Loss of biodiversity should be achieved.
For the other habitats, no quantitative data was available on the impacted sites and on offset sites. We thus cannot
conclude about the achievement of a NNL objective.

3.4

Long-term management

An ecology expert regularly monitors and follows up on the effectiveness of the measures according to the objectives
given in the PAOG (Figure 11) for the duration of the PPP contract (i.e., 20 years). The PAOGs can be updated as soon
as a drift is observed in the objectives or in order to recalibrate the measures towards a more ambitious goal.
--

Dervenn is involved in the implementation and ecological monitoring of the compensation parcels. However
Ter-Qualitech's support seems necessary for the proper implementation of management processes andmonitoring.
Species monitoring is done by expert counting, Dervenn and the ONF.
Follow-up by naturalists is necessary on some measures: wetlands, hermit beetle
Dervenn is committed to compensation results: followed-up by Mayenne Nature environment and theSarthe Birds’ Protection League (LPO). The results are then sent to the National Forest Office.

sampled surveys
surveyvisit

Figure 11: Schedule of the follow-ups (Source: Dervenn)

34

4
Analysis of the project within the
BBOP Standard

35

4. Analysis of the project within the BBOP Standard
Following the overall presentation of the offset project above, this part of the document focuses on the complianceof the project with the BBOP standard and the ten principles listed in the introduction.
This compliance check is based on “Figure 2: principles, criteria and indicators: illustrative chronology presenting the
project” (see Appendix 13), from the document “Standard on Biodiversity Offsets” (BBOP, 2012).
4.1

The offset design

This first table is built chronologically from the commitments made to sustainable development and biodiversity
conservation adapted to the project, to the design phase and the integration of avoidance, minimization andcompensation measures.
A multi-criteria analysis is proposed to assess compliance at each step of the design phase without neglecting theimportant role of the stakeholders and commitment to No Net Loss, key point of the BBOP Standard.
The elements that demonstrate No Net Loss (KBC, risk assessment, offset ability) and the project’s answers to theimpacts and the ecological compensation operational transcription are given in detail.

ORIENTATION AND PLANNING
P1. Adherence to themitigation hierarchy
1-1-1: Impact
assessment undertakenwith stakeholders

P1. Adherence to the mitigation hierarchy
Ecosphère, a consultant firm, conducted an impact assessment in 2006 (part of the EIA)
and completed it with another assessment of the Green and Blue corridors in 2011 inorder to avoid as many potential impacts as possible and refine the HSL route within
the DPU band.
In accordance with French regulation, the impact assessment was undertaken inadhesion to the mitigation hierarchy at all of its stages.
As explained in 1.1, many experts were consulted in different domains:- Human environment (Egis rail, ACOUSTB, Ecopshère)- Agriculture and forestry (SNCF Ingénierie)- Natural environment (Ecosphère, Ecothème, Mayenne Nature Environnement, Liguede Protection des Oiseaux)- Culture heritage (Pierre Lebrun)- Landscape (Pierre Lebrun)-Hydrogeology and geotechnics (Scetauroute-Ouest Infra-Technosol, Hydrosphère)- Hydraulic (Ecosphère-Egis Rail)P4. No net loss (NNL)
4-1-1: Public
commitment to NNL
4-2-1: Key Biodiversity
Components identified

P4. No net loss (NNL)
Eiffage’s corporate sustainability charter on the preservation of biodiversity andhabitats targets the environmental excellence of our projects. A public statement of
the commitment to NNL is available on ERE’s website.
Moreover, a voluntary agreement on sustainable development was signed in 2013
between the SNCF Réseau and ERE in order to promote their mutual commitment infavour of biodiversity beyond the mandatory regulations.
The key biodiversity components (see 1.3) were identified during the EIA thanks to theon ground environmental inventories made by experts, based on the Red Lists at theinternational, European, national and local levels and the local lists of the endangered
species and habitats at the regional, departmental or very local scales. Other tools weretaken into account like the protected areas: ZNIEFFs (Natural areas of flora and fauna)and Natura 2000 areas.

36

P2. Limits to what canbe offset
2-1-1: Risk assessmentof non-offset-able
impacts

P2. Limits to what can be offset
During the impact assessment, the residual impact on each of the potentially impacted
populations of species was evaluated according to its sensitivity, to the potential
breeding and resting area impacted, and to the sensibility level in the Red List and theregional/local representation of the species.
Each residual impact was qualified according to a regulation scale of “very strong”,“strong”, “medium” “low” or “insignificant” impacts at local and regional levels. “Verystrong” corresponds to the destruction of a species with a very high patrimonial value
and a high endemic nature that lives on a site of high ecological value.
This early assessment prevented the destruction of the protected habitats and all the
species in critical danger of extinction (risk of “very strong” and “strong” residual
impacts).
Because a surplus of land was secured for the right-of-way of the line, the volume ofthe sites available and potentially eligible for compensation during the design stage
largely exceeded the compensation needs.
Most of the offset sites were secured before earthworks began in 2013. The risk of nonoffset-ability was thus reduced.

P6. Stakeholder
participation
6-1-4: FPIC fromindigenous peoples
whose rights areaffected by the project
and/or the offset

P6. Stakeholder participation
The project was subject to public inquiry in 2012 (Water Act), during which prior andinformed consent was solicited and given freely (FPIC).
The FPIC was obtained through public meetings organised by ERE during the offset
design phase. These meetings aimed at presenting the project to the inhabitants andlandowners and to taking their informed opinions and remarks into account.

Moreover, the landowners impacted by the project were identified and advised on how
to obtain legal advice or financial arrangements to compensate the ecological impacts(leases, financial compensation, relocation).
LANDSCAPE and IMPACT CHARACTERISATION
P1. Adherence to themitigation hierarchy
1-1-2: Mitigation
measures documented,
implemented,
monitored

P1. Adherence to the mitigation hierarchy
Mitigation hierarchy was the thread through all of the studies carried out by either the
SNCF or by Eiffage. The application of the mitigation hierarchy is detailed in theregulation files (Protected species and Water legislation) drawn up by Eiffage, Setec
and the ONF in 2012. Each regulatory procedure is divided into at least three stages:
 Avoidance
 Minimization/residual impact
 Offset design and measures
The ecological corridors’ assessment was an impact study of the line on the landscapeand could propose measures to maintain the landscape’s ecological dynamics.
Numerous complementary inventories also helped to gain more knowledge on theimpacted sites and fuel the mitigation strategy.
 Exact information on the impacted territory (landscape ecological dynamics,
field inventories) is key to developing an efficient offset programAn assessment and a follow-up of the efficiency of the offset measures are scheduledin the context of the LOTI report (LOTI = Inland Transport Orientation Law) and concern
the minimization and offset measures. In addition, ERE established a socio-economicand environmental observatory that goes beyond the required follow-ups. It
evaluates some of the effects of the HSL on the territory on a larger scale like theimpacts on otter displacements within the country, impacts on the fragmentation ofbats, impacts on farm landscape dynamics, among others.

37

P2. Limits to what canbe offset
2-1-2: Offset-ability
demonstrated

P2. Limits to what can be offset
Offset-ability was demonstrated by not significantly impacting highly
vulnerable/endangered species and protected habitats such as the ZNIEFF and Natura
2000 zones. This could be accomplished thanks to the avoidance and minimization
phases that reduced the residual impacts on heritage habitats.

P1. Adherence to themitigation hierarchy
1-2-1: Residual losses
described in the
Biodiversity Offset
Management Plan
(BOMP)

P1. Adherence to the mitigation hierarchy
The residual losses considered having significant adverse effects are detailed inAppendix 0. For the protected species they are expressed in terms of the surfaces ofhabitats lost per species and in terms of surfaces impacted for the wetlands, ponds,
hedgerows, etc.
It is a synthesis of all the regulation documents submitted by Eiffage for the project(water law, protected species, clearings’ files).

P6. Stakeholder
participation
6-1-1: Stakeholders
identified, informed ofthe plan to design,
implement offset
6-1-2: Records ofinformed consultationand participation of
stakeholders

P6. Stakeholder participation
During the High Speed Line design phase, the SNCF Réseau identified whichstakeholders would be impacted by the project (stakeholders close to the right-of-wayof the line, or those indirectly linked to the construction and the offset). These
consultations were carried out in two phases as the studies progressed, in 1997 and in
2000, and included the analysis of contrasting variants that fostered questions anddebates.
There were three phases to the public inquiry file:the design of the route, which involved broad consultation with the
population (end of 2002 - beginning of 2004), under the auspices of aMonitoring Committee set up on the recommendation of the National
Commission for Public Debate;
consultation of the State services (Spring 2004);
consultation with the elected representatives, socio-economic actors andassociations representing interests concerned by the project (November 2004
to March 2005).
Based on the owner's proposals, the Minister in charge of transportation
approved the Preliminary project summary (APS) in a ministerial decision of
26 January 2006 and asked the SNCF Réseau to put the project to public
inquiry.
Insofar as impacts in agricultural and forest areas were expected, the following bodies
were consulted under the Rural Code (Article L. 112-3):- Chambers of Agriculture- Regional Forest Property Centers (CRPF)
New investigations and parcel surveys were carried out under the Code ofExpropriation in 2011 in order to pinpoint which parcels were to be acquired and which
beneficiaries were to be financially compensated. The owners were informed byindividual notification or, when they could not be identified, notification was posted in
the city hall.
All the elements of this public inquiry are available here.
In addition to the public inquiry, once the contract between the SNCF Réseau andEiffage was signed and the offset designer designated, Eiffage and Dervenn organised
public meetings for the stakeholders (farmers and landowners, among others) to
explain the ins and outs of the project and compensation.
SAFER selected offset sites that could be managed by farmers motivated by andinterested in the ecological approach. The result is guaranteed by Terqualitechs (incharge of land animation) and the sites benefit from a 1 € lease.
SAFER, chambers of agriculture and farmers were consulted to define the management
measures compatible with maintenance by farmers.

38

P9. Transparency
9-1-1: Information
regularly reported to
stakeholders
9-1-2: Independent
review mechanism foroffset design,
implementation

P9. Transparency
Different means of communication were used to make the project and its
progress/evolution known:- ERE’s website: general information, press releases, press kits
- Quarterly news magazine published by Eiffage concerning the major steps of theongoing implementation of the project- Information about the mitigation hierarchy and annual assessments of theimplementation of the mitigation measures and offset for each department.
- Articles and publications in newspapers such as Ouest France (Special edition for the
LGV BPL) in 2017.
Many public conferences and seminars were organized. In order to reach an evenwider audience, a mobile trailer presenting the project circulated throughout the cities
crossed during the 5 years the project lasted.
The ERE/ONF designed the offset but it was closely watched by local authorities thatvalidated all of the 242 PAOG of the offset sites. This guaranteed compliance with theoffset principles.

P4. No net loss (NNL)
4-2-2: Methods for
NNL, equivalence
identified, basis forselection explained
4-1-4: Equivalence
methods address
equity in type,condition, location,
timing4-2-4: Loss-gain (L-G)
metrics identified,
explained, and used for
calculations
4-1-2: Residual losses
quantified, pre-project
biodiversity condition
characterized

P4. No net loss (NNL)
The methodology used for assessing NNL is not the equivalency method suggested by
the BBOP.
(1) Impacted site before
impactΔ(2) Impacted site after
impact=(3) Offset site before
impactΔ(4) Offset site after
impact(1) Indeed, for this project, residual losses were quantified in terms of surface or linear
impacted for species habitats and protected areas. An evaluation of the quality of the
impacted sites was made only for the wetlands, ponds and water bodies (30% of the
impacts in terms of surface), using a project-specific method developed by experts. The
calculation of residual impact for each species and protected area is detailed in the
appendices 2 to 8.
(2) The state of the impacted sites was never assessed after impact so it was consideredthat the site did not conserve any ecological functionality after the impact (worst case).
(3) (4) As for the offset sites, the state before and after impact was assessed with thesame criteria as the impacted site before impacts.
 The data available on wetlands, ponds and water bodies allows us to demonstrate
No Net Loss for those areas But, currently, the lack of quality data on the species habitats makes us unable togive an exact equivalency calculation and thus demonstrate the achievement of No
Net Loss for species
In terms of equivalence, all the sites address equity:
in type, the principle of “like for like”, e.g., compensate a wetland with awetlandin condition, by providing, at least, the same habitats with the same ecological
functionality
in location, by compensating near the impacts (most of the offset sites arewithin a 2 km band around the line (see figure 7 in 2.4.3).

39

 As the project is 182 km long, with an offset program designed globallyand in a fungible context, we cannot relate a specific impacted site with a
specific compensation site.
 We plan to analyse the localisation of the impacted and compensatedsites in terms of habitat types and ecological functionality, as part of the BPL
HSL environmental observatory.
 There are 920ha of compensation distributed on 242 compensation sites
In terms of timing, even if some of the offset sites were implemented before the works
began (see 2.5.3 - Immediate compensation ponds), most of the sites were
implemented after the occurrence of the impact.
 Now, the “Biodiversity Act” passed in France in 2016 makes this principle a strong
requirement.
 This is one of the most complex aspects for such a linear infrastructure projects.
During the design-building process the responsibility for offset design, site
identification/contracting and offset works is often delegated to the design-builder,who, in turn, must wait for the project to be attributed before actively searching foroffset sites. Thus, the implementation of the compensation has to be made in a shorttime before the beginning of the line’s works.
 To implement offset works before the impacts, we anticipated the offset design andthe search for land as much as possible even before the project was attributed.
 At date, the BPL project cannot claim No Net Loss of biodiversity but can affirm a No
Net Loss approach
SELECTION OF OFFSET ACTIVITIES and LOCATIONS
P5. Additional
conservation outcomes
5-2-1: Leakage
assessment undertaken

P5. Additional conservation outcomes
Leakage assessment was not undertaken for the project.

P3. Landscape Context
3-1-1: Landscape level
planning for offset
locations
3-2-1: Future
developments
considered in offset
design3-1-2: Offset
contributes to regionalgoals
3-2-2: Government
invited to incorporate
offset in plans

P3. Landscape Context
An effort was made to assure that each site was integrated into the ecological network(ponds, hedge networks) and the biodiversity reservoirs/hubs in order to increase each
one’s ecological potential and to facilitate the movement of species. The ecologicalnetworks were determined during the EIA in the landscape component realized in 2011
for the SNCF Réseau by Ecosphère.
Regional ecological coherence schemes existed and were taken into account whenrelevant for connecting or re-connecting it so that species could mix genetically.
 To our knowledge, the compensation sites have not been integrated back into theplanning documents as “ecological areas”
 However, since 2018, French regulation requires that offset sites be localized in afree-access national database to make planning more readily accessible
The future development of cities crossed by the linehas also been taken into accountfor the offset locations. Indeed, no offset measures were implemented in theimmediate vicinity of the three major cities crossed by the high-speed line. The
potential changes and expansions of these cities were addressed more specifically withthe local departments’ authorities in the “Railway junctions” file, in order to determine
and plan urban sprawl zones so as to not compromise offset measures in the short,medium and long terms.
 Future development projects other than urban sprawl have not been integrated
given that no other structuring project in the vicinity of the line was known at that
time

40

P4. No net loss (NNL)
4-1-3: Gains calculated
relative to without
offset condition, which
is characterized
4-2-5: Application of
L-G metrics,
equivalence methods inoffset design shows
NNL
4-1-4: BOMP describes
offset design andevidence on
assumptions
4-3-1: Sources of risk,
uncertainty andmeasures to address
them documented
4-3-2: Milestones for
progress to NNL
established andmonitored

P4. No net loss (NNL)
Concerning the metrics used, for this project, a surface and ecological functionality
approach was used. Each residual impact on a species’ habitat after the avoidance andminimization phase was defined in terms of surface “to be offset” and in terms offunctionalities for the ecological requirement.
Offset ratios were thus determined, being more or less important as per thevulnerability of the species, the type and heritage of the habitats (see offset ratio use
details in each part of Appendix 0).
 These expert-made ratios made it possible to define the offset debt
 The lever of improvement here is to better explain the ratios used on the offset
measures, showing how they take the uncertain success of the on-site offset
measures into account. More globally, explain the uncertainty associated with theecological trajectories of the offset sites and how this risk is addressed.

P5. Additional
conservation outcomes
5-1-1: Evidence that'with minus without'offset gains are
additional
5-2-2: Leakage risks
addressed in
implementation

P5. Additional conservation outcomes
Does not apply to this project.

All the sites will be monitored until 2036 (see 3.4). The PAOG (development, orientationand management plan) (see 3.1) can be adapted every 5 years. Dervenn, the offset
project manager selected by Eiffage to design, implement and monitor the offset until
2036, lead the consortium that realised these documents.
In addition, regular scientific surveys will be made to assess the success of the measures(functionality of the habitats, inventoried species, etc.)

RECORD OFFSET DESIGN
P10. Science andtraditional knowledge
10-1-1: Use of best
available science inoffset design,
implementation
documented in
Biodiversity Offset
Management Plan
10-1-2: Use of relevant
traditional knowledge
documented, withapproval

P10. Science and traditional knowledge
Several scientific experts worked on the offset design and its implementation.
- Asconit and Hydrosphère are experts in hydraulics and hydrogeology: they worked on
the elaboration of the offset methodology for the wetlands, ponds, water bodies andwatercourses using the reference methodologies adapted to this project.
- Dervenn, Setec and the ONF contributed their expertise in the dimensioning of thecompensation through the naturalist inventories they made, but also from theirseparate experiences in the field of compensation.
The consortium led by Dervenn drafted an offer with a component specifying the useof expert knowledge (on-ground experience) combined with scientific knowledge forthe design and implementation of the offset.

41

4.2

The offset implementation

This second table shows the operational extension of the offset project.
Again, taking into account the important role of the stakeholders and people impacted, a multi criteria analysis is
proposed to assess compliance at each step of the implementation process.
Finally, the project’s long-term management is demonstrated and outcomes assessed.
IMPLEMENTATION, MONITORING, ADAPTIVE MANAGEMENT, REPORTING
P6. Stakeholder
participation
6-1-3: Implementation
roles of stakeholders
defined in Biodiversity
Offset Management Plan
6-2-1: Grievancemechanism in operation

P6. Stakeholder participation
The roles of the stakeholders in the implementation of the offset are clearly
defined in the Dervenn run consortium offer.
Dervenn is the project manager and designer of the offset.
The consortium is composed of- Ter’Qualitechs, an agronomist and land development officer- Ouest’am, a planning consultant- Cardin TP, an earthworks company also in charge of the landscaping- Dervenn: an ecological engineering company and design office.
A centralized system for processing and resolving grievances was set up in the formof spreadsheets sent by Dervenn to the contracting authority (Eiffage) every month
until 2036. Grievances are prioritized by importance. The most sensitive are treatedfirst. Each grievance resolved is noted and archived in the table, which gives an
overview of the procedures in progress.

P7. Equity
7-1-1: Biodiversity Offset
Management Plan
references stakeholder
agreements
7-1-2: Evidence ofindigenous people, local
communities satisfied,rights respected
7-1-3: Loss of people’suses and values
compensated

P7. Equity
The agreements between the stakeholders are not clearly referenced except thosebetween- the SNCF Réseau – the French State and delegates – and Eiffage;- the SNCF Réseau and Eiffage concerning the voluntary agreement for sustainable
development on the project;- Dervenn and Eiffage for the offset design and implementation;- Eiffage and the farmers (rural environment leases) based on the voluntary will tomaintain and preserve, in some places, agricultural activity on the compensationsites. These leases are based on a “give-and-take” approach; strict rules of use andmaintenance are defined for the farmer who in return enjoys the usufruct of theplot.
Public meetings held during the design of the compensation project and even after
its implementation revealed that farmers were satisfied with this system.
The farmers are the most impacted by the offset project. However, an INRA (French
National Institute of Agronomic Research) study, one of the studies of the BPL
observatory, shows that 72% of the farmland used for compensation had lessagronomic value than the average farmland redistributed to farmers after the land
reclamation.

P8. Long-term outcomes
8-1-1: Evidence of
implementers' requisite
management andtechnical capacity
8-1-2: Legal and financial
mechanisms for long

P8. Long-term outcomes
Dervenn, the company responsible for the implementation of the offset, had todemonstrate its technical and management capacities during the call for tender
made by Eiffage in 2014. The other important aspect was the ability to manage theoffset for a period of 25 years (until 2036).
Long-term financial management is secure because it was included in the total
calculations of work. A schedule was also set for the 25 years of evaluation andmonitoring.

42

term implementation inplace
8-2-1: Risk management
and mitigation (Ref: Indic
1-3-1) implemented
8-2-3: Monitoring,
Evaluation and Adaptive
Management
8-2-2: Independent
auditing of outcomes

The mitigation hierarchy and offset measures were implemented between 2012
and 2017, in accordance with the contractual commitment between Eiffage and the
SNCF Réseau.
Each site is monitored at least once a year and a scientific/technical assessment of
the efficiency of the measures will be made regularly until 2036 (see 3.4)
Dervenn and the ONF audit the sites annually. Dervenn then reports a synthesis of
the audit. All of the possible defects are noted and the means put into place for
their resolution are indicated in the report of the following year. Success indicatorssuch as the re-colonization by a plant or animal species are ways of verifying that
offset has met its objectives.
In the event of failure, corrective measures are implemented as many times asneeded until they succeed. This is a clause of the contract. If necessary, themethod of management of the site concerned will be adapted via a revision of the
management plan (PAOG).

43

CCONCLUSION

44

Conclusion
Realizing this study was a good way to get to know the BBOP standard better. It enabled us to analyse and compare Eiffage’s
practices with the 10 principles and identify progress axis in our approach. It let us take a step back and analyse and better
understand the specificity and complexity of the mitigation hierarchy implementation on linear infrastructure projects, given
the wide volume of compensation and the design/implementation temporality compared to main works planning.
To assess this project against the BBOP standard while not having directly taken it into account during the offset design (dueto the chronology) required a synthesis of the fifty documents we had in our possession, and a critical analysis of the global
offset project.
A long process of avoidance and minimization permitted the reduction of the residual impact to the minimum and ensured
that offset measures would be efficient and sustainable. Among the most remarkable avoidance measures is the way the route
was adapted to avoid natural areas at stake. This gave the line a particular shape. Different types of minimization measures
were implemented but the one with the most impact is the one to preserve the existing ecological transparency by theconstruction of 248 structures to maintain the hydraulic and terrestrial corridors for fauna and flora.
Offset measures were implemented for the impacts we were not able to avoid or reduce: 247 ha of wetlands of high ecological
functionality, 213 ponds of high ecological functionality with 213 ha of terrestrial habitat for amphibians, 12 km of watercourse
restoration, 36 km of riparian forest creation, 44 km of hedges planted or restored are some examples.
In total, compensation measures were implemented on 242 sites that represent 920 ha, each site gathering various measures.
To ensure the sustainability of the measures, a long-term management and monitoring plan has been scheduled until 2036.
All the steps of the mitigation hierarchy were executed with great attention and most of them are in line with the key provisionsof the BBOP Standard.
The BPL HSL goes beyond the French laws of the time, but given that it was designed before the publication of the BBOP
standard, it did not follow all of the principles. No Net Loss assessment, based on the ecological equivalency principle can only
be justified for the wetlands and ponds. For the other species habitats, No Net Loss can only be proved in terms of volume of
habitat offset but not in terms of quality. Therefore, the achievement of NNL for the whole project cannot be proved but wecan say that the project followed a NNL approach, beyond regulatory obligations.
The assessment of the project against the standard was very useful because it helped us to methodically analyse the applicationof the mitigation hierarchy to the line and define axis of improvement for current and future projects.
It also highlights that some criteria are complicated to implement on huge linear projects conceded: the proximity to impact
and the implementation before the impacts. This is due to the high volume of land necessary for the offset, the high landpressure on agricultural lands, and to the (short) time available to build and implement the offset project. All this in a context
where the infrastructure works must begin as rapidly as possible after contracting.
The only solution to fulfilling (or partially fulfilling) these objectives is to anticipate the issues from the tendering stage, hand inhand with the design teams. A detailed knowledge of the areas involved and early structuring of the environmental
management (during studies, works and maintenance) are also keys to the success of the mitigation hierarchy application.
This work will clearly contribute to upgrade our skills on French and international projects and put forward our motto, “makethe difference”.

45

A
APPENDICES

46

Appendix 0: Detailed data for all impacted
species and habitats
1. For habitats
1.1.Wetlands
 Provisional impact before avoidance and reduction
313 plots of wetlands were identified in the DPU band. The level of each of them was qualified after the analysis of 3
functions: hydraulic, purifying, biologic (Appendix 10)
Level
wetland6
Number of wetlands concerned in
the DPU area
Surfaces of wetlands concerned in
the DPU area (ha)


1

Level
wetland7

2

Level
wetland8

3

Level
wetland9

4

Total

117

56

80

60

313

225.28178.69250.21181.52

836

Avoidance and minimization measures

The location of landscape forms, permanent soil deposits, hydraulic basins and annex equipments within the rightsof-way was studied in order to avoid the areas of environmental concern, particularly the identified floodplains andwetlands.
In addition, the technical rights of way were optimized to avoid sensitive sites or stations whenever possible.
To minimize the impacts, the project tended toward preserving the ecological functionings of the natural habitats
near the line, especially the wetlands, ponds, watercourses; the “bocage” (primarily a network of hedges and thewood edges were restored.
Residual impact assessment

The project’s total residual impacts is composed of 254 ha of which 80% are on wetlands, levels 1 to 3:
Levelwetland
Residual impact70.46 ha1

Levelwetland40.36 ha2

Levelwetland3

93.23 haLevelwetland50.39 ha4

Residual
Impact254 haOffset design

Concerning the re-creation or restoration of wetlands, the SDAGE of the Loire-Bretagne, the regional direction ofwater development and management, recommended that the compensation measures be implemented within thesame watershed, functionally equivalent in terms of the quality of biodiversity. Failing this, the compensation should
cover an area equal to at least 200% of the area removed. The long term management and maintenance of thesewetlands had to be guaranteed.

6

Level 1 corresponds to a very functional wetland with regard to the three functions
Level 2 corresponds to a moderately functional wetland with regard to the three functions
8
Level 3 corresponds to a poorly functional wetland with regard to the three functions
9
Level 4 corresponds to a non-functional wetland with regard to the three functions
7

47

Wetland compensation can be implemented on non-humid plots, or on areas whose ecological value is limited andlikely to be favourably modified for flora and fauna and for wetland functions (phytopurification, buffering role
against diffuse pollution, denitrification, flood expansion zones, flow control and minimum water level). Some parcelsof high ecological interest can also be used for compensation sites with provisions for sustainable maintenance.
ERE's stated intention was to implement "wetland" compensatory measures with the re-creation or restoration of
wetlands that were at least functionally and ecologically equivalent.
To determine the equivalence, a standardized methodology was used to “rate” the impacted wetlands and then torecreate wetlands with, if not the same rating, a better one.
The restoration goal is to maintain or upgrade wetlands to Level 1 or to at least Level 2. Because of the high stakesof the Level 1 habitat, ERE voluntarily increased the ratio traditionally used in France for Level 1 wetland impacts: for1 ha of level 1 impacted, the offset is of 1 ha of level 1 + 1 h of level 2 instead of only 1 ha of level 1.
The following ratios were thus applied:
Impacted wetland

Offset ratios

1ha Level 1

1 ha Level 1 + 1 ha Level 2

1ha Level 2

0.5 ha Level 1 Or 1 ha Level 2

1ha Level 3

0.25 ha Level 1 Or 0.5 ha Level 2

1ha Level 40.25 ha Level 2

 Offset requirement
In total, by applying the previous ratios, the offset requirement for 240.5 ha is: 70.5 ha of wetland level 1 and 170 haof wetland level 2:
Impacted
Level 2
Level 1 wetland
Level 3 wetland
Level 4 wetland Total Impact
wetlandwetland
Residual impact
70.46
40.36
93.23
50.39
254 ha70.46 ha Level 1
Total offset per+
40.36 ha Level 246.615 Level 2
12.59 Level 2
wetland type70.46 ha Level 2
Total offset
requirement240.5 ha(surface)

Offset design and implementation

Wetlands being an incredible reservoir of biodiversity, the offset is pooled with an offset for protected species, as
described in 1.1.9 (fungibility principle) and in the species detailed offset explanations.
In total, 247 ha of wetlands were implemented, almost equal to the impacted surface while increasing the associatedfunctionalities.
Wetlands

Residual impact

Requirement

Functionality
Surface in ha

Level 1 to 4
254ha

Level 1 to 2
240.5 haOffsetimplemented
Level 1 to 2
247 ha48

Different kinds of measures were implemented for the wetlands (Figure 12):
1. Conversion of plots for cultivation and the preservation of it into wet meadows
Wetlands have been exploited since ancient times and this anthropic dynamic has created subnatural environments.
Some of these wetlands were drained; others were ploughed and reseeded to enhance their agricultural production.
A compensation measure consists of converting cultivated plots to wet meadows. The elimination of the drains of
the cultivated plots, which dried up the original wetland, makes for a restoration of a wetland. Agricultural
management conventions of these plots can be of extensive grazing types, with or without fertilization, or latemowing meadow types.
2. Conversion of poplar plantations into megaphorbia or alluvial forest
In the rural landscape, poplars are occasionally planted at the bottom edges of the wet valleys. These plantations
occasionally exist in natural environments. The poplars, which consume a lot of water, tend to reduce the floristic
diversity of wetlands.
The conversion of these poplar plantations is an interesting compensatory measure to look at. Depending on thepotential of the station, the restoration of the wetland can be directed towards megaphorbia (high grass prairie on
cool wet soil) or alluvial forest regeneration.
3. Wetland reopening or rehabilitation
Some wetlands owned by farmers cannot be drained or easily used for pasture. Land abandonment appears and leads
to woody colonisation.
These wetlands are often small in size but are of a high patrimonial interest.
Reopening or rehabilitating them offers offset opportunities.
4. Redevelopment of wetlands by clearing a pond
In order to improve the ecological continuity (fish and sediments) of the rivers, some artificial ponds whose sourcecame from rivers were eliminated.
These often unauthorized lakes were created in topographic depressions or on wetlands.
These measures make it possible to compensate wetlands and to improve the quality of the watercourses in thewatersheds.
5. Layout of the major bed
This measure restores the river’s more natural flow within slopes of less than 3% that allows the creation of
permanent or intermittent wetlands.
Where water was already more present, this measure constituted an improvement of its quality.

250,00200,00150,00100,0050,00
0,00

Figure 12: Main offset measures occurrence (ha) (Source: Eiffage)

49

These measures are pooled on the 247 ha of wetland offset.
For example, the invasive species struggle is often associated with the implementation of a reed bed and thevegetation closing struggle, and the conversion into a wet meadow is often associated with drainage.

1.2.Ponds and water bodies


Projected impact before avoidance and reduction

280 ponds and 149 water bodies were identified in the DPU band. The level of each impacted pond and lake wasdetermined according to the number of species it hosted and the density of its aquatic vegetation. As for thewetlands, level 1 corresponds to a very functional pond/water body, level 2 to a moderately functional pond/water
body and level 3 to a pond/water body in poor condition (i.e., eutrophication). See methodology detailed in Appendix
11.

Number and surface of ponds impacted:
Ponds
Number
Surface in ha

Level 120
0.75

Number and surface of water bodies impacted:
Water bodies
Level 1
Number3
Surface in ha
0.97
 Avoidance and minimization measures

Level 243
1.37

Level 3
217
7.52

Total
280
9.64

Level 213
6.80

Level 3
133
35.27

Total
149
43.04

Figure 13: Example of a provisional fence and awareness panel (Source: Eiffage)

50

Phase

Measures proposed- Strict limitation of the rights of way on the sites of ecological concern for
amphibians

Design- Adaptation of the work period outside of the migration and reproduction periods- Provisional fences and panels (Figure 13) were positioned near the resorts withstrong ecological stakes (outstanding wetlands, botanical stations, amphibian
ponds), to prevent vehicles from entering and to avoid the destruction of thehabitats outside of the necessary rights of way

Construction- Control of discharges caused by the installation of capping basinsResidual impact assessment

Thanks to avoidance and reduction within the DPU band, only 110 ponds, out of the 280, presented residual impacts,
91 of which host native or protected amphibian species. Thus, impact on 170 ponds was avoided, representing a totalof 5.4 ha:
Ponds
Number
Surface in ha

Level 1na
0.5

Level 2na
1.25

Level 3na
2.4

Residual impact
110
4.2 haFor water bodies, almost 30 ha were avoided over 149 impacted initially:
Water bodies
Number
Surface in ha

Level 1na
0.97

Level 2na
5.1

Level 3na
7.8

Residual impactna13.9 ha Offset requirement
The ratios were the same as those applied for ponds and water bodies.
-

The “water law” offset requirement for ponds:

Impacted pond

Level 1

Level 2

Level 3

Residual impact

0.5
0.5 ha Level 1+
0.5 ha Level 2

1.25

2.4

1.25 ha level 2

1.2 level 2

Total offset per
wetland type
Total offset
requirement

Total
Impact4.2 ha3.45 haPonds often being of a high biodiversity interest, this offset implementation was fully pooled with the offset
requirement for the impacts on protected species (see part 2.4.1 on fungibility and amphibian offsets).
-

The “water law” offset requirement for water bodies:

Impacted water bodies

Level 1

Level 2

Level 3

Total
ImpactResidual impact

0.97

5.1

7.8

13.9 haTotal offset requirement/

51

The water law offset was considered only on sites where no protected species were detected. Illegal water bodies were notrecreated, especially those set up along the rivers. This measure is in line with the objectives of the SDAGE Loire-Bretagne, interms of water quality and restoration of ecological continuities.
The impacts on water bodies were not considered in the final ecological requirement because they were globally considered
non significant regarding ecological functions.
However, their presence presented an opportunity for wetlands offset. Thus, partially or indirectly impacted water bodies
were rehabilitated into wetlands, through partial or total land filling. Likewise, this erasure of water bodies set up along theriver could be an offset for species habitats loss.


Offset design and implementation

Proposals for offsets of the impacted ponds and water bodies located on the route of the line are different as they are destined
to disappear. They are also different for those on the near periphery, as they can be indirectly impacted during the construction
and operation phases.
-

For ponds

The offset ponds are landscaped ponds designed to host spontaneous hygrophilous vegetation, which favours recolonisation by amphibians and semi-aquatic insects. These ponds were created, when compatible with earthworks
planning, the year before the beginning of the construction phase so they would be full during the amphibians’
reproduction period in spring.
"Immediate" compensation ponds for those directly impacted were created as close as possible to the impact, andwhen possible for those within the project’s right-of-way and with a significant heritage (presence of protected
species). 91 immediate compensation ponds were thus created. The integration of these ponds within the right ofway of the project provided a transitory habitat for amphibian species before the destruction of the impacted ponds.
These ponds were established with the equivalent surface, hydrological and biological functionalities as the impacted
ponds. The surface of each had to be between 50 and 500 m². Indeed, in terms of efficiency for the reception ofamphibians, it seemed preferable to create several small ponds than a large pond of 1000 m2. The depth of eachpond varies between 20 and 50 cm. A deeper area (1 to 2 m) prevents it from drying out too frequently. Amphibian
habitats (also hibernaculum for reptiles), made of piles of wood and/or stones, complete the functional featurearound the ponds.
The offset was first and foremost sought within a restricted radius of 600 m around the impacted pond. The
immediate compensation pond was located as close as possible to the impact and as far as possible from the project
footprint (Figure 14). Depending on the land constraint (availability of land eligible for compensation) offset proposals
could be made up to a radius of 1800m (maximum movement distance of amphibians) around the impacted pond.

INITIAL STATE

Figure 14 : Pond and water body offsets (Source: Eiffage)

FINAL STATE52

The immediate compensation ponds were built before the works began to allow time for the water quality to stabilize
and for the growth of vegetation and sufficient food sources for amphibian larvae. Samples and transfers of water,
sediments, aquatic plants and amphibians (at the beginning of the breeding season) were taken from the impacted
ponds to initiate biological activity in the newly created pools.

Figure 15: Offset ponds design principle (Source: Ecosphère)

When an immediate compensation pond could not be created within the project’s right of way, new ponds, or
restored existing ponds, were set up in a more remote perimeter, but not further than 500m away from the line.
These ponds were established to compensate
the impacts on amphibian populations and on
their breeding grounds. The number of ponds
was calculated according to the ratios definedby the regulatory offset measures for thedestruction of protected species. They werecalled "substitute ponds" and werepositioned in order to compensate for thelack of ecological continuities for theamphibians due to the line’s right-of-way.
They correspond to the 122 ponds created inaddition to the 91 immediate compensation
ponds. Hedges were added to create
ecological corridors for the amphibians andfor semi-aquatic mammals, insects and bats
(Figure 16).
The ponds created after the impact
occurrences were positioned according to theecological conditions of the stations
concerned. The existing networks of ponds
and local populations of amphibians
determined by the species inventories werealso taken into account (data from the impact
studies and complementary inventories).
In order to secure all of the offset ponds, ERE- Figure 16: Connection principle between landscape biological elements
ONF registered with the Local Urban Plan and (Source: ONF)
established a charter of good maintenance ofthe ponds with the pond owners.

53

In total, the offset ponds represent:
Ponds
Residual impact
Number110
Surface in ha
4.2 haRequirementna3.45 haOffset implemented
213
4.45 haWe can note that the surface of the offset implemented is almost 30% higher than the ecology “water law” requires
and 6% higher than the residual impacts, increasing the habitat’s global quality.

1.3.Watercourses
Provisional impact before avoidance and reduction

To have a better estimate of the project’s impact and anticipate the regulations before the PPP attribution, Eiffage
had further studies conducted by Asconit to complement the first ones done by the SNCF Réseau and by Ouest
Aménagement.
The functionality of the 110 water flow zones impounded by the line, (in agreement with the criteria of the Water
Development and Management Scheme (SAGE)) were qualified according to a standardized methodology detailed inAppendix 12.
Every watercourse was thus given a functionality rating from “Very Good” to “Very Bad” thanks to 4 criteria: the flow,
the bank profiles, the differentiated substrate and the aquatic organisms observed.

Total

Very Good
/

Good
6

Average30

Bad
69

Very Bad5

The project thus impacts mostly average and bad quality water-flows.


Minimization measures

The project was designed to ensure the best hydraulic and ecological transparency of the infrastructure, keeping in
mind the planning documents: the Water Development and Management Scheme (SAGE), the flood risk prevention
plan (PPRI) and a circular of the Ministry of Ecology and Sustainable Development (24 July 2002).
Two kinds of measures are to be distinguished: measures during the design phase and those during the work phase.
Phase
DesignConstruction

Minimization measure proposed- Implantation of the viaduct piers outside the minor bed- Adaptation of the hydraulic structures depending on the context (tunnel, viaduct,
nozzle)- Definitive derivations were favoured over temporary derivations to limit the
disturbance of the environment- A network to collect, decantate/filtrate and restore rainwater helped to protect
the water resource: collection basins, ditches and the like. The basins were sizedaccording to the local environmental stakes. This network was largely conserved
for the operation phase of the line.

During the design phase, a focus on the upkeep of the hydraulic and ecological continuities led us to implement fourtypes of crossing-structures, minimising the final impacts on more than 8 km of water-flows.
Type of works
Minimization measure / purpose
Viaduct
Type 1- implantation of the viaduct piers
outside the minor bed- hydraulic transparency

54- hydraulic transparency- preservation of the banks andthe minor bed (including during
the construction phase)- maximum shortening of thelength of the structure to limit the
shadow

Tunnelcrossing
structure(Strong stake)
Type 2Tunnelstructure(Low tostake)
Type 3crossing- hydraulic transparency- fish transparency- presence of a bench for thepassage of the small fauna- concrete slab covered with areconstituted bed (low-flow bed)

medium- hydraulic transparency during
flooding- presence of a bench for thepassage of the small fauna

Hydraulic nozzle(without issue)
Type 4

Synthesis of the structures for the restoration of hydraulic surface continuities:

Type of structure

1

2

3

4

Number of each type ofstructure

6

5

100

137

Residual impacts

Residual impacts, when a hydraulic work bridge or nozzle is implanted on the watercourses, destroy the aquatic
habitat, especially the spawning grounds and degrade the daytime circulation of fish (behavioural blocking at light /dark transition).
Residual impactWatercourse impacted

7200 lm

Riparian forest (aquatic mammals + fish)

8.07 haSpawning grounds (fish)

214 lmOffset design

Various offset measures were advocated:1.

Tools and techniques to upkeep, restore and maintain spawning ground sites for aquatic fauna in minor or
major water-beds:-

Re-establish a functional hydraulic connection between the spawning grounds and rivers during the flood periods:

55oRestoration and maintenance of ditches (cleaning, decluttering of logs, restoration of tadpole trees on theriverbanks)o Construction and/or restoration and/or maintenance of hydraulic structureso Land securing and sites environmental managemento Signature of ecological maintenance contract
Recreate various flow facies by bringing materials with a granulometry adapted to targeted species
 200 m² of created/restored spawning grounds for 100m² destroyed
2. Upkeep or restoration of ecological continuities
Some already existant hydraulic structures did not allow ecological transparency (wrong location, bad sizing,
structures no longer in use, etc.).
Offset involved replacing, repositioning or eliminating some of the structures to re-establish the ecological continuity(with the agreement of the structure’s owner or keeper). This offset is coupled with upstream and/or downstream
restoration measures.
 100 linear meter functionality restored for 100 linear meters of habitat loss
3. Watercourse re-naturation
Many small water flows have been previously interfered with which often leads to a complete disappearance of thespecies habitats.
The meandering can lengthen the watercourse, reduce the slopes and restore the initial sinuous morphology andassociated functionalities (flood expansion, species habitats, water purification, sediment decantation, etc.). This
technique calls for mechanical excavator works, material disposal and plant-based engineering techniques.
 100 linear meters of re-naturated watercourses for 100 linear meters of habitat loss
4. Waterside vegetation
The vegetation alongside the watercourse provides a diversified and specific habitat for a community of insects andbirds; the underwater roots also contribute to habitat diversification of water fauna. Above all, the shadow provided
by the trees incites the return of animal and vegetal species, by cooling the water temperature and favouring its
oxygenation.

 200 linear meters of riparian forest restoration/creation for 100 linear meters impacted

Offset requirement

The ratios applied here refer only to the water law offset ratio and not to the protected species law ratio.

Watercourse impacted
Riparian forest (aquatic mammals +fish)
Spawning ground (fish)Residual impact

Offset ratio

Offset requirement

7200 lm*1

7200 lm

8.07 ha*2

16.14ha214 lm*2

428 lmOffset implementation

This offset comes under the water law and is closely related to the fish and aquatic-mammals offset under theprohibition of protected species destruction derogation procedure.
Fungibility measures allowed for the total offset implementation of:

Watercourse impacted
Riparian forest (aquatic mammals + fish)
Spawning grounds (fish)

Offset requirement

Offset implementation

7200 lm
16.14ha428 lm

12075 lm
36056 lm / 25ha
428 lm56

1.4.Linear hedges
Provisional impact before avoidance and reduction

A detailed inventory of hedgerows was conducted on the project’s footprint perimeter (including excavations andrefilling) plus on 50 m of buffer area on both sides, representing a prospection area of 3,927 hectares.
According to the methodology presented in Appendix 9, the following potential impacts were found:1407 hedges inventoried
Tree hedges
75%

191 km long

Common Oak (Quercus pedunculata) in 87% of thehedges.
Other species: Wild Cherry (Prunus avium), Ash (Fraxinus
excelsior), Sweet chestnut (Castanea sativa), Field maple(Acer campestre), present in 25 to 35% of the hedges.

46 species

3 invasive species
Shrub hedges
25%
Dominated by Blackthorn (Prunus spinosa) (75%) andcommon hawthorn (Crataegus monogyna) (68%)
Other species: Dog Rose (Rosa canina), Common
Hazel (Coryllus avellana), Black Elder (Sambucus
nigra), present in a medium to high abundance, from19 to 50% of the hedges)

Tree hedge (degradedwith no shrubs due tothe repeated passageof animals or gear)
10%
65% of the hedges are in ditches and /or 50% are on embankments
Complete structure
shrubs, trees: multi stratum65%



Shrub structure only
25%

Minimization of the linear of hedges

Some of the impacts on the hedges in the 50m bands around the project’s route were avoided because of the project’s
reduction/optimisation of the land footprint and protection during the work phase; this reduction was marginal,
however, given that the “bocage” structure is very dense in these areas.
Residual impact
Potential impact
191000Hedges for amphibians and insects


Residual impact
44610 lm /44.61 ha

Offset requirement and implementation

Hedges need to be offset only when they are useful for protected species. The offset is thus designed according to
the amphibian and insect offsets (see 2.3 and 0). Of the 191 km of hedges within the project’s footprint plus the 50m
buffer areas on both sides, 44.6 km are considered to be residual impacts for protected species.
The offset requirement concerning the hedges is detailed species by species below. It was defined according to themethodology used for each species (Appendix 4 and 9).
Residual impact
Hedges for amphibians and insects

44.61 haOffset requirement
21.3
ha
for
amphibians
7 ha for insects

Offset implementation
44.61 ha(21.3 for amphibians, 21.6
ha for insects)

57

Offset design

The hedges were planted to fill in the rowsof the relictual hedges (Figure 17). The newor restored hedges are planted for thelandscape but also serve biodiversity
compensation for amphibians and insects.
Compensation concerns direct habitat
destruction or indirect connectivity
replanting
between habitats.
New hedgerows have therefore beenplanted to complete the continuities and torecreate the “bocage” network, an
outstanding landscape feature of the areas
crossed. Hedgerows were positioned as
close as possible to the nuclei of the Figure 17: Hedgerows plantation principle (Source: Eiffage)
populations of the known species. These
hedgerows are dotted with trees with high jets. The species selected were among those naturally present in thedepartments crossed and when possible plants purchased came from local strains.
By default, some impacts on isolated trees were transcribed in linear terms, which corresponded to width from theline’s right-of-way (i.e., 40 m per tree).
In addition, 100m of hedges per compensation pond were voluntarily planted, pooled for certain species ofamphibians, insects and chiroptera. These measures contributed to the temporal and spatial continuity of habitats.

58

2. Species
2.1.Birds
Provisional impact before avoidance and reduction

The impact assessment and the complementary studies included a total of 70 protected bird species present, or likely
to be present, in the project area or nearby.
23 of these species were particularly at stake (very rare locally, regionally or even nationally) and formed the subjectof a detailed study. The impacted surfaces represent the potential nesting or resting sites within the project footprint:
Use name

Scientific name

Number of Number of sites
Surface impacted
individuals impacted

European honey buzzard
Hen harrier
Wood lark
Common grasshopper warbler
Common firecrest
European nightjar

Pernis apivorus
Circus cyaneus
Lullula arborea
Locustella naevia
Regulus ignicapilla
Caprimulgus europaeus

5
138
148
121
49
64

1
2
4
1
0
3

5.5 ha4.3 ha3.52 ha0 ha
0 ha
21.6 haEurasian hobby
Hawfinch
Short-eared owl
Sand martin
Eurasian hoopoe
Eurasian thick-knee
Black woodpecker
Common house martin
Red-backed shrike
Lesser spotted woodpecker
Montagu's harrier
Little owl
Zitting cisticola
Cetti's warbler
Long-eared owl
Eurasian sparrowhawk

Falco subbuteo
Coccothraustes coccothraustes
Asio flammeus
Riparia riparia
Upupa epops
Burhinus oedicnemus
Dryocopus martius
Delichon urbica
Lanius collurio
Dendrocopos minor
Circus pygargus
Athene noctua
Cisticola juncidis
Cettia cetti
Asio otus
Accipiter nisus

76
19
21
68
208
176
161
138
207
75
10
50
/
/
/
360

1
2
1
0
3
18
1
6
1
3
2
19
1
6
4
4

6.2 ha2.1 ha3.25 ha0 ha0.65 ha85.13 ha8.5 ha//15 ha
13.80ha12.65ha0.7 ha3.4 ha14.3 ha
17 ha

Common kingfisher
Total

Alcedo atthis/

3

0.4 ha218 ha59



Avoidance and reduction measures

Use name
European honeybuzzard
Hen harrier
Wood lark
Commongrasshopper warbler
Common firecrest
European nightjar

Eurasian hobby

Hawfinch

Proposal for mitigation- phasing of works: outside of the period from May to August (breeding period)- regeneration of selvedges with local species to avoid the cut-off effect- phasing of works: outside of the period from March to August (breeding period)- plantations on either side of the line to facilitate its crossing
No impact expected  no mitigation- clearing work carried out outside the nesting periods which are from May to July
- clearing work carried out outside the nesting periods which are from April to July
- clearing work carried out outside the nesting periods which are from April to August- regeneration of selvedges with local species to avoid the cut-off effect- adaptation of the route- clearing work carried out outside the nesting periods which are from April to August- viaduct construction to maintain corridor functionality- clearing work carried out outside the nesting periods which are from April to July
- regeneration of selvedges with local species (especially chestnut trees) to avoid the cut-off effect

Short-eared owl

No impact expected  no mitigation

Sand martin

No impact expected  no mitigation

Common housemartin- clearing work carried out outside the nesting periods which are from April to August- installation of birdhouses before the beginning of the works- phasing of works: from 1 April to 31 August- protection perimeter- preliminary identification of potential breeding areas- clearing work carried out outside the nesting periods which are from April to the middle of August- regeneration of selvedges with local species to avoid the cut-off effect
The destruction of the couples’ housing took place outside the species’ nesting period (i.e., outside theperiod from April to August)Red-backed shrike

No impact expected  no mitigation

Lesser spotted
woodpecker- clearing work carried out outside the nesting period, which is from March to July.
- regeneration of selvedges with local species to avoid the cut-off effect- phasing of works: from 1 April to 31 August- protection perimeter- preliminary identification of potential breeding areas- Felling of trees and buildings outside the period from March to August (breeding period)- installation of birdhouses- follow-up on breeding pairs- clearing work carried out outside the nesting periods which are from April to August- viaduct construction to maintain corridor functionality- works on the banks carried out before the nesting period (end of April to August)- viaduct construction to maintain corridor functionality- clearing works carried out outside the nesting periods which are from March to August- regeneration of selvedges with local species to avoid the cut-off effect- viaduct construction to maintain corridor functionality- plantation of hedges parallel to the HSL to limit the risk of collision

Eurasian hoopoe
Eurasian thick-knee

Black woodpecker

Montagu's harrier

Little owl
Zitting cisticola
Cetti's warbler

Long-eared owl
Eurasian sparrow
hawk- clearing works carried out outside the nesting periods which are from March to August

Common kingfisher- works on the banks carried out before the nesting period (end of April to August)- viaduct construction to maintain corridor functionality

60



Residual impacts assessment

Because of avoidance and reduction measures, including landscape design, residual impacts were cut down to 2 bird
species. The local and regional residual impacts are detailed in Appendix 2.
The residual impacts only concerned agricultural lands.
SpeciesUse Name

Latin nameEuropean honey buzzard
Hen harrier
Wood lark
Common grasshopper
warbler
Common fire crest
European nightjar
Eurasian hobby
Hawfinch

Pernis apivorus
Circus cyaneus
Lullula arborea
Locustella naevia

Short-eared owl
Sand martin
Eurasian hoopoe
Eurasian thick-knee
Black woodpecker
Common house martin
Red-backed shrike
Lesser spotted woodpecker
Montagu's harrier
Little owl
Zitting cisticola
Cetti's warbler
Long-eared owl
Eurasian sparrowhawk
Common kingfisher
Total

Regulus ignicapilla
Caprimulgus europaeus
Falco subbuteo
Coccothraustes
coccothraustes
Asio flammeus
Riparia riparia
Upupa epops
Burhinus oedicnemus
Dryocopus martius
Delichon urbica
Lanius collurio
Dendrocopos minor
Circus pygargus
Athene noctua
Cisticola juncidis
Cettia cetti
Asio otus
Accipiter nisus
Alcedo atthis

Residual impact assessment
Regional
Local scale
scale
Low
None
None
None
Low
Low
Low
None

Yes/NoSurface
impacted

No
No
No
No

None
Low
Low
Low

None
Low
None
None

No
No
No
No

None
None
Low
Average
Low
Low
None
Low
Average
Low
Low
Low
Low
Low
Low

None
None
None
Average
None
None
None
Low
Average
Low
None
None
None
None
None

No
No
No
Yes
No
No
No
No
Yes
No
No
No
No
No
No

85.15 ha13.81 ha91.14 haAvoidance and minimisation measures reduced the area affected by almost 60% and also avoided impact on 21
species that would otherwise have been affected.

Potential impact

Residual impact

Number of species

23

2

Surface impacted

218 ha91.14 haOffset requirement and implementation

The Eurasian thick-knee and the Montagu's harrier nest within intensive crops in the two departments concerned.
The choice was made not to compensate for the potential breeding environment impacted with the same type ofenvironment. Given that intensive cultivation is not threatened in this region, it does not seem advisable toencourage the practice which may present an interest for certain species but which, in general, rather undermines
biodiversity by standardizing landscapes.
Given the different nature of the elements considered, this approach leads to the non-application of a ratio sensu
stricto between the quantification of compensation measures and the quantification of impacts.

61

Compensation therefore aims to reinforce the existing potential breeding sites and to diversify the food source by
converting cultivation to grassland. According to the bibliography, the density of the Eurasian thick-knee varies from
1 to 4 couples per 100 ha. In theory therefore, the impacted area corresponds to the territories of about 3 Eurasian
thick-knee couples. To strengthen the nesting sites, it was proposed to create 8 untilled plots per potential territory(couple), i.e., 24 plots in total. The uncultivated 24 plots are distributed so as to improve the breeding success of theEurasian thick-knee equivalent to 85 ha of territory favourable to its nesting.
The diversification of the resources improves the quality of the Eurasian thick-knee’s habitat. 5 ha of herbaceous
wasteland or crop conversion are proposed per potential territory, i.e., a total of 25 ha.
The Montagu harrier will also benefit from these new herbaceous zones. An additional 25 ha were proposed
specifically for this bird.
Residual impact
Eurasian thick-knee

85.15 haMontagu's harrier

13.81 haTotal

91.14 ha

Offset requirement
24 plots without seeds (72 ha)+ 25 ha culture conversion+ 25 ha culture conversion
24 plots without seeds (72 ha)+ 50 ha culture conversion

Offsetimplementation
24 plots without
seeds (72 ha)+ 53.5 ha culturalconversion

Offset measures

The 2 species with residual impacts particularly sensitive to the loss of habitat and feeding resources decreased. The
proposed offsetting measures aimed to respond to both of these damages.
1.

Direct destruction of individuals and broods avoided = 72 ha

The breeding season of the Oedicnemus begins at about the same time as the soil is laboured for late crops, whichsignificantly heightens the risk of nest destruction. The parcels intended for late-growing crops (usually sunflowers),
located outside the LGV right-of-way, were offset. The offset consisted of delimiting 40 m X 20 m plots with no seeding
along the planted lines so that potential breeding sites were preserved and to encourage birds to settle there. The
Oedicnemus appears to be a species that can easily change its spawning spots. These plots are also preferential sites
for surrogate breeding. An ecology expert chose the positions of the plots.
In order to convince an operator to accept this work constraint (non-incentive subsidy), the measure had to be
combined with an improvement of the quality of the habitat, such as the conversion of cultivation to meadow.
2.

Improvement of the food web and habitat quality = 53.5 ha

The success of bird breeding is closely linked to the availability of food sources. In general, the compensatory
measures seek to improve the birds’ food webs.
Actions to improve the quality of the habitats of many of the species nurture food dynamics:- Conversion of crops to grasslands or herbaceous wastelands- Diversification of the resources (grasses, legumes).
Herd management has two advantages in meeting both nesting and feeding requirements.
These actions must be accompanied by a policy of reducing inputs, both chemical herbicides, insecticides and nitrogen
fertilization. Limiting inputs can result in financial compensation for the farmers but also in alternative proposals tohomogenize the landscape, such as by rotating crops and by alternating annual and perennial crops. Here again,
proximity to the agricultural world is crucial to ensure the credibility of the measures and the sustainableappropriation of new farming techniques.

62

2.2.Bats
Provisional impact before avoidance and reduction

16 species of bats were identified during the impact assessment; all are protected. Inventories were conducted
throughout the potential habitats within the project’s route: woods (old trees with cavities), churches, castles, andold buildings with attics, barns, or basements.
SpeciesUse Name
Common pipistrelle
Grey long-eared bat
Kuhl's pipistrelle
Greater horseshoe bat
Geoffroy's bat
Greater mouse-eared bat
Lesser horseshoe bat
Bechstein's bat
Daubenton's bat
Barbastelle
Common long-eared bat
Natterer's bat
Serotine bat
Common noctule
Whiskered bat
Alcathoe bat


3
1 or 2
1
1
1
1
1
1
1
1
1 or 2
1
1/
1/

Avoidance and reduction measures

Species

All the species of bats

Latin name
Pipistrellus pipistrellus
Plecotus austriacus
Pipistrellus kuhlii
Rhinolophus ferrumequinum
Myotis emarginatus
Myotis myotis
Rhinolophus hipposideros
Myotis bechsteinii
Myotis daubentonii
Barbastella barbastellus
Plecotus auritus
Myotis nattereri
Eptesicus serotinus
Nyctalus noctula
Myotis mystacinus
Myotis alcathoe

Number of sites where it wasobserved

Measures- Worksite installation at more than 1000 m from the bats living places- No buildings to be destructed during the birthing period (1 June to 15 September) orin winter (15 November 15 to 15 March)- Route crossing structures implementation in the right of way of chiropteran corridors(viaducts, hydraulic structures) + hedges landscaping to lead to the crossing structures- Anti-collision hedge and a final 2 m high fence on both sides of the line

Residual impacts assessment

After avoidance and reduction, direct and indirect impacts on each of the species was assessed, according to thespecies’ sensitivity, flight behaviour, collision risk and disruption of displacement corridors.
Among the 16 species inventoried, 8 are subject to residual impacts that concern wood surface impacts. The risk ofcollision was the reason to classify the species with an average local impact but with no residual impact. Given that
this issue affects few colonies, the residual impact at the population scale is considered to be low, with no incidence
on the population subsistence, thus no residual impact was taken into account.

63

Species

Evaluation of the residual impact on the populations
Regional Residual
Use Name
Latin nameLocal scale
Surface impacted
scale
impact?
Common pipistrelle
Pipistrellus pipistrellus
Low
None
Yes
12.58 haGrey long-eared bat
Plecotus austriacus
Low
None
No
Kuhl's pipistrelle
Pipistrellus kuhlii
Low
None
Yes
11.97 haGreater horseshoe bat
Rhinolophus ferrumequinum Average
Low
No
Geoffrey’s bat
Myotis emarginatus
Average
Low
No
Greater mouse-eared bat Myotis myotis
Low
Low
No
Lesser horseshoe bat
Rhinolophus hipposideros
Average
Low
No
Bechstein's bat
Myotis bechsteinii
AverageLow
Yes
4.87 haDaubenton's bat
Myotis daubentonii
Low
Low
No
Barbastelle
Barbastella barbastellus
AverageLow
Yes
10.75 haCommon long-eared bat Plecotus auritus
Low
Low
Yes
5.83 haNatterer's bat
Myotis nattereri
Low
Low
Yes
5.49 haSerotine bat
Eptesicus serotinus
Low
None
Yes
0.61 haCommon noctule
Nyctalus noctula
Low
None
No
Whiskered bat
Myotis mystacinus
Low
Low
Yes
17.46ha
Alcathoe bat
Myotis alcathoe
Low
Low
No
69.56ha (22.7 ha
Total
mutualised)Offset requirement

Common pipistrelle

Pipistrellus pipistrellus

12.58 ha1

Offset requirement
Hedges, forestationand ecologicalcorridors
12.58 haKuhl's pipistrelle

Pipistrellus kuhlii

11.97 ha2

23.94 haBechstein's bat

Myotis bechsteinii

4.87 ha4

19.48 ha

3
2
2
1
2
(*2.7
mutualised)32.25 ha11.66 ha10.98 ha0.61 ha34.92 ha146.42 ha(61 ha mutualised)

Bats

Barbastelle
Barbastella barbastellus
Common long-eared bat Plecotus auritus
Natterer's bat
Myotis nattereri
Serotine bat
Eptesicus serotinus
Whiskered bat
Myotis mystacinus
Total

Residual impact:
Hedges, forestation andecological corridors

Offset ratio

10.75 ha5.83 ha5.49 ha
0.61 ha17.46 ha69.56 ha(22.7 ha mutualised)Thus, 61 ha of woods (biological trees), senescence wood islands, hedges and artificial shelters had to be created.
Offset implementation

Bats

Offset requirement

All species
61 ha
Total

61 ha

Offset implementation
31.9 ha of woods
44.61 ha of hedges
43 artificial lodgings
76.5 ha64

The three biological compartments necessary for the optimal fulfilment of the life cycle of bats were heeded: breedingsites, resting sites and the presence of physical or biological elements deemed necessary for the reproduction of thespecies considered to have biological connections with the bats.
Proposals to offset the impact on chiropteran have therefore been articulated around the following axes:
Provide breeding lodgings by planting new woodlots, establishing islands of senescence, building habitats
specific to bats close to the line.
Create/protect resting places with new forestations encourage the implantation of “islands of aging”, orsenescence, and make specific arrangements for sustainable access to the buildings near the line.
Create/restore/protect biological connections and hunting grounds: riparian forest, hedgerows, permanent
meadows and pastures.
Thus, the four main offset measures are:-

The plantation of woodlots or groves
Hardwood plantations are part of the clearing obligations. Forests sere most often planted near existingwoodlots or when disconnected from a forest are larger than 4 ha.
Additional forest areas were planted specifically for bats. They are a priority in the continuity of forestation
under clearing obligations and as often as possible near impacted forests.
Priority is given to the projects near the forestation sites impacted by the HSL.
The sizes of the groves vary as per the available areas but remain under one hectare. Above one hectare agrove becomes a forest.
Oak (pedunculate and sessile) is the preferred species for afforestation but edaphic and stationary
constraints bring other species into consideration. The indigenous species are always given preference alongwith the selection of plants from local strains.

-

Senescence, or the creation of “islands of aging”
Implanting islands of old wood is beneficial to a large procession of species that thrive on old wood. Bats,
cavity nesters, reptiles, small mammals and some birds like the picus are some of them.
An island of senescence is a small place left to evolve freely and preserved until its natural end, that is, until
the final collapse of the trees. These islands are composed of trees with a particular biological value (large
cavities, aging wood). For security reasons, they are chosen in areas unfrequented by the public.
An island of senescence is highly recommended for the compensation of this group because it offers the
optimum habitat for a majority of the chiropteran family.

-

The installation of artificial lodgings
These breeding and/or hibernation sites meant for a large
number of bat species are generally found in buildings, but also
in forest areas. They provide the essential habitats that ensure
the life cycle of bats.
This measure is particularly important for the Kuhl’s pipistrelle
and the common pipistrelle bat, species closely related to a
constructed environment and significantly impacted by thedestruction of the buildings along the line’s right-of-way.
The lodgings were proposed to improve and facilitate thereception of bats in buildings (e.g., residences, farms, barns)
close to the HSL’s track. Access to the “cottages” is limited by
the installation of grids (horizontal bars) and specific nest
boxes (Figure 18). These were affixed primarily on the buildings
located near the impacts.
Three buildings near the right-of-way are specifically set aside
for biodiversity compensation, especially for bats. The Figure 18: Artifical lodging for bats (Source: ERE)
buildings also benefit other compatible groups, including birds.

-

The plantation of hedges to create and restore biological connections necessary for species displacement
and feeding65

2.3.Insects
Provisional impact before avoidance and reduction

Of the 20 insect species inventoried along the project’s route, 3 are protected by the regulations of protected species(the Southern damselfly, the Hermit beetle and the Great Capricorn beetle).
Additional field studies were carried out in the extended 200 m band around the route planned by ERE to refine theimpacts:
SpeciesUse Name
Southern damselfly

Latin name
Coenagrion mercuriale

Hermit beetle

Osmoderma eremita

Great Capricorn beetle

Cerambyx cerdo

Number of sites where it was observed
4 watercourses
70 stations, favourable
2,556 lines, favourable (m)200 cavity trees with potting soil
18 trees with presence indicators
32 sites
153 trees impacted
2,322 m lines of hedges

Avoidance and reduction measures

Species

Proposals for mitigation

SouthernDamselfly- Concerning the destruction of individuals:
Habitat avoidance was the best solution. In the case where avoidance was impossible, the mostfavourable period for cleaning works was from September to November. A rotation of work over
3 years was recommended to limit the impact on the populations.
- Loss of habitats: Rehabilitation of certain areas located in close proximity to the impacted area. Bank
landscaping work to clarify the tree layer and to create "gaps" (minimum 10m.)
favourable to the Southern Damselfly in order to connect the various favourable
sectors was supposed to be much more beneficial than the loss of a few dozen metersof habitat.
 Conservation of the most favourable sunny shoreline areas. An annual mowing can also
be implemented on very scrubby streams with the export of vegetation.
 Recreation or conservation of grass strips of 10 meters wide along the banks. Theseshould not be crushed or mown during the main emergence period of imagos (early
May to mid-July), to avoid their direct destruction. In general, it would be desirable too Conserving the grassland areas bordering the watercourses.
o Permanent re-watering of ditches under favourable conditions and according
to opportunities, primarily on linear close to core populations to optimize thechances of colonization by the species.
- Cutting of the axes of movement
When unavoidable, the cutting of a displacement axis was compensated by the reconnection ofcertain peripheral sectors and/or by rehabilitating the hydrographical network.

Hermit beetle- Since there is no proven impact, no tree movement or population is planned. On the other
hand, the potting soil in the trees with traces of the presence of the species has been transferred
to other tree cavities close to the right-of-way.
- Plantation of hedges in connexion to the existing ones with ecological functionality and acontinuity of the ecological corridors

66Great Capricorn
beetle- Plantation of hedges in connexion to the existing ones, an ecological functionality (for thesaproxylic insects) and a continuity of the ecological corridors- Fencing during the works phase to enforce the rights of way

It was planned to plant hedges in connection to the remaining hedges. These hedges would have an ecological
function (for the saproxylic insects) and would also ensure a functional continuity of the ecological network.
Preference was given to planting tall tree and shrub species indigenous to the area and already present in hedgerows.
The potting soil from the 8 trees showing trace presence of the Hermit beetle species, impacted directly by the
project, was moved to other tree cavities near the impacted trees.
Residual impact assessment

The avoidance and reduction measures for the Southern damselfly allowed for no residual impact on this species.
SpeciesUse Name
Southern damselfly
Hermit beetle
Great Capricorn
beetleLatin nameEvaluation of the residual impact on the populations
Local
Regional
Residual impact?
Linear impacted
scale
scale
Low
Low
No

Coenagrion
mercuriale
Osmoderma eremita Average

Low

Yes

320m

Cerambyx cerdo

Low

Yes

8442m

Average
Total

8602m

2,322 m of hedges sheltering the great Capricorn beetle were impacted, and 153 isolated trees were cut down during
the works (Figure 19). By default, the impact on isolated trees is transcribed into a linear corresponding to the widthof the right-of-way of the line at the point of impact considered, i.e., on average approximately every 40 m. The linear
corresponding to these 153 trees is therefore 6,120 m. Added to this is the linear impacted hedges, or 2,322 m. We
obtain a total of 8,442 linear meters impacted for the great Capricorn beetle.
To translate the impact on the Hermit beetle into a linear of “bocage”, the linear corresponding to the width of theright-of-way of the line at the point of impact, i.e., 40 m, was used by default. Thus the impacted linear corresponding
to these 8 trees is 320 m.

67

Figure 19: Hedges offset principle (Source: Ecosphère) Ecological requirement
The great Capricorn beetle is common along the route. Its relative abundance in the departments crossed by the HSL
and its colonization dynamics in the northern departments of the Loire justifies an average level of compensation(x3), less than the Hermit beetle.
The Hermit beetle remains a very sensitive species within the woodland environment because of the scarcity of its
habitat. A strong ratio (x8) was used for the calculation of the requirement.

Osmoderma eremita
Cerambyx cerdo

Residual impact
320 lm8442 lm
Total

Offset ratio
83

Ecological requirement
2600 lm
25300 lm
27900 lm / 27.9 ha

Offset implementation

On the field, 27.9 ha of offset have effectively been implemented, divided as follows (Figure 20):

Hedgerows plantation and restoration
Hedgerows upkeep
Borders plantation / upkeep
Isolated trees plantation
Copse plantation

Figure 20: Distribution of the measures concerning the offset hedges (Source: Eiffage)

68

Hedgerows and borders take up a total of 21.6ha (21,600 lm) and isolated trees and copse take up 6.3 ha.
The compensatory measures are aimed at controlling the main sources of regression of the Hermit and GreatCapricorn beetles by improving the spatial and temporal continuity of their habitat. These two insects have low
dispersal abilities, especially the Hermit beetle, whose movements hardly exceed a few tens of meters. Offsets mustensure habitat breeding near the known breeding sites with a viable initial population by implanting deep-cavity trees
and senescent trees. The supply of potential habitats must also be renewed with plantations over time to ensure thelong-term sustainability of the environment.
Thus, the offset of the saproxylic beetles is based on two major sets of measures:- Actions related to the “bocage” environment:- Planting of hedgerows and isolated trees (both species: the great Capricorn beetle and the Hermit beetle)in the immediate vicinity or in the continuity of the site affected by the works of the project. The choice ofplantation sites is oriented towards sectors where the populations are known or are coherent with theexisting "bocage" network in order to fill its discontinuities.
- Restoration or conservation of hedgerows and isolated trees (both species). Restoration occurs when thehedge is not dense enough to be functional as opposed to a hedge to be conserved that does not require
any intervention during the first year of the implementation of the offset measures.
- Maintenance of hedgerows, isolated trees (both species) to minimize the risk of a break in the continuityof tree cavities and increase the potential of existing hedgerows over time.
- Orchard plantations (Hermit beetle): The Hermit beetle, unlike the Great Capricorn beetle that isdependant on oak, is not as selective of the choice of plant species.
- Conversion of crops to grasslands or creation of grass strips: The environment adjacent to the hedgerows
plays an important role in the proper integration of the offset measures in the species’ environment: aculture can become a hostile environment for the moving individuals.
- Actions related to the forest environment:- Plantations of deciduous forests and groves (both species): Action implemented on farmland relatively
close to a local population of saproxylic insects (Great Capricorn and/or Hermit beetle).
- Treatments of the edges (both species): The sunnier edges are often very attractive to the saproxylic
insects, which prefer and seek the trees that are well exposed to the rays of the sun.
- Establishment of islands of aging (Hermit beetle): Small populations having exceeded the optimal criteriaof economic exploitability benefit from prolonged silvicultural cycles.
- Establishment of islands of senescence (Hermit beetle): Small standing trees left to evolve freely until theirend, that is, until they collapse.
These measures of creating and restoring offsets of hedges for the saproxylic insects also benefit the reproduction
and movements of the amphibians nearby.

69

2.4.Terrestrial and semi-aquatic mammals
Provisional impact before avoidance and reduction

While considering the DPU band, the following potential impacts were estimated:

Use name

Latin name

Numberof sites
impactedEurasian otter
EuropeanbeaverEurasian water
shrew
Miller's watershrew
Commondormouse
Eurasian red
squirrel
Europeanhedgehog

Lutra lutra

27

Surfaceofriparian
forestimpacted(Ha)
3.75

Castor fiber/

Neomys fodiensLinearofwatercourses/banks
impacted
M (ha)

Surfaceof forest
impacted(Ha)

Linear ofhedges
impacted(m)

Total
estimated
impact(ha)

6103 (1.22)

4.97 ha

1.44

427 (0.09)

1.53 ha88.07

19950 (3.99)

16.14 haNeomysanomalus

14

8.07

19950 (3.99)

16.14 haMuscardinus
avellanarius

24

87

Sciurus vulgaris

/

150.9

Erinaceus
europaeus

/

150.9

45000m(22.5 ha)112850 m(56.4 ha)112850m(56.4 ha)109.5 ha150.9 ha150.9 haAvoidance and reduction measures

More than 1000 basins were built and maintained throughout the main works to treat the water before it ran into thewatercourse. Depending on the sensitivity of the site, the basins were equipped with filtration systems to prevent accidental
pollution. 245 Modul'AP® prefabricated filtration modules were used on the construction sites. Eiffage patented the device
and the Institute of Roads, Streets and Infrastructures awarded its efficiency in 2014 for mobility (IDRRIM) in the "clever
initiatives" category. The basins are permanent structures and are used today for the storage and decantation of runoff water.
Species

Eurasian otter

European beaver
Eurasian water
shrew

Miller's water shrew

Proposals for mitigation- Impact reduction measures in the design phase: Adaptations made on hydraulicstructures- Measures to limit the risk of collision: the mesh holes of the fence that separate therivers from the tracks are all less than 5 cm wide.
- Measures to reduce mortality during the construction phase: adaptation of theearthworks to favourable periods.
- Measures to ensure the functionality of transparency works- Measures to reduce mortality in the construction phase: Systematic recession ofearthworks rights-of-way, identification of potential burrows in the final project rights-ofway, establishment of habitat opening techniques, implementation of protection mark-up- Measures to reduce mortality during the construction phase: Clearance of rights-of- wayat the most favourable time, measures to limit the partitioning of shrews, measures tolimit the risk of polluting the living environments of the species- Measures to limit the partitioning of shrews: Keep the elements structured on the banks
and in the beds. Preservation of natural banks- Measures to limit the risk of polluting the species’ living environments: measures to limit
any alteration of the physic-chemical quality of the wetlands, whether during constructionor the operating phase.

70- Measures to reduce mortality during the construction phase: Preparatory work, inparticular deforestation and hedge felling, carried out outside of the breeding season, as
well as before the hibernation period, between August and November.
- Measures to increase the transparency of structures:
Common dormouse Installation of a hedge continuum on the higher wildlife crossings Preservation of the banks and elements of the environment (vegetation) underhydraulic structures
Transparency structures were developed to meet the challenges of ecological continuity
Eurasian red squirrel (hydraulic structures allowing the passage of terrestrial wildlife, small wildlife passages
and crossings with large fauna).
Transparency structures were developed to meet the challenges of ecological continuity
European hedgehog(hydraulic structures allowing the passage of terrestrial wildlife, small wildlife passages
and crossings for large fauna).
All of these measures helped reduce the primitive impacts, which caused for smaller residual impacts.


Residual impact, definition

After the avoidance and the reduction on the habitats of these species (rest, reproduction, feeding) an analysis of therisk of mortality during the construction phase and the corridors of displacement identified only four of the sevenspecies initially concerned as impacted by the project and requiring compensation: The Eurasian otter (Lutra lutra),the European beaver (Castor fiber), the Eurasian water shrew (Neomys fodiens), and the Miller water shrew (Neomys
anomalus).
The residual impact only concerns the impacts on the riparian forest.
SpeciesUse Name
Eurasian otter
European beaver
Eurasian water shrew
Miller's water shrew
Common dormouse
Eurasian red squirrel
European hedgehog



Latin name
Lutra lutra
Castor fiber
Neomys fodiens
Neomys anomalus
Muscardinus
avellanarius
Sciurus vulgaris
Erinaceus europaeus
Total

Local
scale
Average
Average
Average
Average
Low

Residual impact assessment
Regional
Surface
Yes/Noscale
impacted
Average Yes
3.75 haAverage Yes
1.44 haLow
Yes
8.07 haLow
Yes
8.07 ha
Low
No

Low
Low

Low
Low

No
No
24.21 ha (on aglobal 8.07 ha
area)

Offset requirement

The 8.07 ha of impacted habitats concerning the two Shrews are within the rivers in the right-of-way of the HSL. The
impacts on the Otter and the Beaver are also within this linear. Thus, the offset provided for the two Shrew species
includes the expected offset both for the Otter and the Beaver in terms of area, i.e., 25 ha. The average compensationlevel applied to mammals is 3.1.

Species

Residual impact on riparian
Offset ratio
forestOffsetrequirement

Eurasian otter
European beaver
Eurasian water shrew
Miller's water shrew
Cumulated surface
Raw surface

3.75
1.44
8.07 ha8.07 ha21.33 ha(On a global 8.07 ha area)

7.5 ha2.88 ha16.14 ha24.21 ha50.7 ha
25 ha

2
2
2
3
3.1 (average ratio)

71

Offset Implementation

The establishment of diversified riparian forests improves the quality of the habitats of the riverbank species and has
effects the quality of the water. These niches represent important resources for the semi-aquatic mammals. The
offset for mammals focuses on this action.
Watercourses are chosen for compensation according to their potential for the Shrew’s habitat. Their location is close
to the watercourses where the presence of these mammals has been proven. The proximity of the sites of provenpresence makes it possible to favour the extension of the distribution of the species and to consolidate the current
populations.
The offset measures for the otter and the beaver were proposed close to where their appearances were recorded
during the complementary studies.
This offset, by way of the derogation of the prohibition of protected species destruction procedure, is closely related
to the fish and to the watercourse offsets, by the way of the water law.
The measures benefiting mammals in these procedures were thus fungible and allowed for a total offset
implementation of:Offset requirement
23.4haRiparian forest

Offset implemented
36,056 lm / 25ha

2.5.FishProvisional impact before avoidance and reduction

5 of the 26 fish species discovered in the project’s area are protected by a national decree and are on
the protected species list.
Species

Usual name

Latin nameNorthern pike

Esox lucius

Brook lamprey

Lampetra planeri

Common dace

Leuciscus leuciscus

Amur bitterling

Rhodeus sericeus

Brown trout

Salmo trutta

Status of sensitivity

Number of watercourses
impacted

Very sensitive

13

Moderately sensitive

4

Slightly sensitive

3

Moderately sensitive

5

Moderately sensitive

11

Avoidance and minimization measures

Fish populations- Safeguard fisheries were installed to save as many Northern pikes as possible. The safeguard
fisheries were realized in accordance with the Fishing Federation and water administrations.
- Protection of the water flows during construction to filter fine particles that pollute water(Figure 21)

72

Figure 21: Temporary sanitation (Eiffage patent: Modulap®)

Residual impact assessment

Regulations protect only the fish breeding areas, namely the spawning grounds.
After avoidance none of the Northern pike, Brook lamprey, Common dace and Amur bitterling spawning grounds
were directly impacted. The potential indirect impacts (clogging of watercourses, pollution, etc.) were managed
through watercourse protection measures.
Some direct residual impact could not be avoided for the Brown trout. Even if the impact was low and potentially nil
because of the mobility of the spawning grounds, it was esteemed that the project could destroy 2 specifically Trout
spawning grounds.
Species

Residual impact assessment

Northern pike

Esox lucius

Local
scale
Low

Brook lamprey

Lampetra planeri

Low

None

No

Common dace

Leuciscus leuciscus

Low

None

No

Amur bitterling

Rhodeus sericeus

Low

None

No

Brown trout

Salmo trutta

Low

None

Yes

Usual name

Latin nameRegional
Residual impact
scale
None
No

Value

0.05 ha (214 m) of riparian
forest and 0.05 ha (214 m)of spawning ground

Offset requirement

The level of compensation applied is deliberately moderate because the conservation issue for the Brown trout
remains limited due to the absence of a wild strain identified during the impact studies. The trout recorded during
the inventories were taken from the local fishing hatcheries.
Habitats impacted
Riparian forest
Spawning grounds

Residual impact
0,05 ha (214 m)
0,05 ha (214 m)

Offset ratio
22

Offset requirement
0.1 ha (428 m)
0.1 ha (428 m)

73

Offset measures

The purpose of the offset is to implement tools and techniques to maintain, restore and manage the spawning sites
in the minor bed:
1. By restoring a functional hydraulic connection between the spawning grounds and the river during floods:
restoration and maintenance of ditches (cleaning, uncluttering of ice jams, restoration of tadpole trees on
the banks);
creation and/or restoration and/or management of hydraulic structures;development of management agreements;
land control and environmental land management.
3. By reconstituting various flow facies by adding granulometry materials specific to the Brown trout (Figure 22)

Figure 22: Creation of habitats in the watercourses (Source: ONF)



Offset implementation

The fish offset, by way of the derogation to the prohibition of protected species destruction procedure, is closely
related to the watercourse offset, by way of the water law.
The measures that benefit fish in both procedures are fungible and allow for a total offset implementation of:

Riparian forest

Offset requirement
428 lm / 0.1 ha

Spawning grounds

428 lm / 0.1 ha

Offset implemented
36056 lm / 25 ha
428 lm

74

2.6.


Amphibians

Provisional impact before avoidance and reduction

The design office ECOSPHERE had already done studies on the impact of the project on the natural environment
during the Pre-Project preparation and the public inquiry file prior to the DPU; the SNCF Réseau then did specificinventories between 2009 and 2010.
Here we focus on the complementary study of the amphibian populations impacted by the project carried out by thedesign office DERVENN. The study is limited to amphibian breeding and development sites (ponds and water bodies),and does not include migration routes or overwintering sites. The objective was to draw up an exhaustive list of theamphibian species present in each pond impacted by the project, and their respective numbers.
The 78 ponds in the project footprint (right-of-way + 12 meters on each side) were studied through an exhaustive
quantification of the individuals of each of the amphibian species. 56 of the ponds host protected species:
15 presented a very high heritage interest (presence of at least 3 species of newts and/or nestingsites of importance for common and agile frogs)
53 showed an average or low heritage interest (presence of one or more of the amphibian species,
and attested breeding site)
6 did not present any species
4 were not prospected (because of access difficulties)
Of the 15 species of amphibians inventoried, 14 are on the UICN red list in France, classified Low concern. Five ofthem are classified Near Threatened.
Number of stations whereobserved /78

Species

Conservation
statusUse Name
Common Midwife Toad
Common ToadNatterjack Toad
Agile Frog
Edible Frog
Common Parsley Frog
European Tree Frog
Fire Salamander

Latin name
Alytes obstetricans
Bufo bufo
Bufo calamita
Rana dalmatina
Pelophylax esculentus
Pelodytes punctatus
Hyla arborea
Salamandra salamandra

Alpine Newt
Northern Crested Newt
Marbled Newt
Palmate Newt

Ichthyosaura alpestris
Triturus cristatus
Triturus marmoratus
Lissotriton helveticus

10
26
6
29

LC
NT
NT
LC

Smooth Newt
Blasius Newt

Lissotriton vulgaris
Triturus x blasii

8
2

NT
LC

5
30
0
48
38
4
17
14

LC
LC
LC
LC
NT
LC
NT
LC

75



Avoidance and minimization measures

Species

Proposals for mitigation

All the species ofamphibians

- Rehabilitation of habitats and reproduction sites (ponds, bodies of water) as close as
possible to the habitat destroyed- Choosing a suitable work period. The optimal intervention period for backfilling-impacted
ponds extends from October to January (common toads and common frogs are likely to bein the water as of January). The problem remains for 4 species that spend the winter in thewater in larval form: the common Midwife toad, the Edible frog, the common Parsley frog
and the Fire salamander. These 4 species are present in 50 of the 78 inventoried ponds.
Amphibians could be present in these 50 ponds during the autumn and winter; it was best
to rescue the larvae present before destroying the pond.
- Avoid the destruction of individuals by preventing them from returning to the pond during
the breeding season. Simply placing a fence around the pool in winter or autumn can do
this.
- In the event that the route crosses an identified migration route, the construction ofcrossing structures for amphibians (batrachoduc type) had to be considered.

Residual impact assessment

78 of the 280 ponds within the DPU band hosted heritage or protected species. After avoidance and reduction, 110
ponds were impacted, among which 68 hosted heritage or protected species.
The analysis of the direct and indirect impacts (species sensitivity, protection, impacts on habitat, resting, breeding,displacement corridors, etc.) on these ponds and the associated habitats permitted a definition of the amphibian
residual impacts.
Of the 14 species impacted:
6 species are impacted by article 2 of the “Habitat-Fauna-Flora” European directive, that is, theirreproduction and rest areas are protected;
7 are impacted by article 3 of this directive, that is, only the individuals are protected, not their habitat.
Of the 68 impacted ponds, 42 were concerned by “article 2 species” and 26 by “article 3 species”.
SpeciesUse Name

Residual impact assessment
Latin name

Local
scale

Regional
scale

Yes/NoNumber of ponds
impacted

Surface
impacted(ha)
3.70

CommonMidwife Toad
Common Toad

Alytesobstetricans
Bufo bufo

Low

Low

Yes

8 (0.31ha)

Low

Low

Yes

25

Natterjack Toad

Bufo calamita

AverageLow

Yes

3 (1.17ha)

11.76

Agile Frog

Rana dalmatina

Low

None

Yes

30 (5.42ha)

107.06

Edible Frog

Pelophylax
esculentus
Pelodytes
punctatus
Hyla arborea

Low

None

Yes

2

Average

Low

Yes

4

Low

Low

Yes

12 (0.42ha)

Salamandra
salamandra

Low

None

Yes

14

Common Parsley
Frog
European Tree
Frog
Fire Salamander

23.01

76

Alpine Newt

Ichthyosaura
alpestris
Northern Crested Triturus cristatus
Newt
Marbled Newt
Triturus
marmoratus
Palmate Newt
Lissotriton
helveticus
Smooth Newt
Lissotriton
vulgaris
Blasius Newt
Triturus x blasii

Average

Low

Yes

12

AverageLow

Yes

25 (0.71ha)

42.96

AverageLow

Yes

6 (0.1ha)

9.29

Low

None

Yes

30

Average

Low

Yes

9

Average

Low

Yes

2

Total


68 ponds

137.95ha

Offset requirement

The species under article 3 of the “Habitat-Fauna-Flora” European directive are considered "umbrella" species withvery important ecological functionalities. Their offset was not a legal obligation but Eiffage took it upon itself to takethese species into account. Indeed, at this scale, the landscape is vegetal and eutrophication is low which is conducive
to favourable amphibian displacements, thus a high probability of their presence. The ZNIEFF considers all of theamphibian species in Brittany decisive; given the species heritage value and sensitivity to the project works, they werealso offset.
Compensation ratios for impacts on both breeding ponds and terrestrial habitats were therefore proposed for eachspecies according to their sensitivity and national and regional protection status. Their frequency of appearance inthe departments crossed by the High Speed Line as well as their conservation status in the close perimeter of the line
was also taken into account (data extracted from the results of the inventories carried out during the impact studies
and the complementary studies at the definition of offset measures).
Species

Ponds requirement

Use Name

Latin nameCommonMidwife Toad
Common ToadNatterjack Toad
Agile Frog

Alytes obstetricans

Edible Frog

Pelophylax
esculentus
Pelodytes
punctatus
Hyla arborea

Bufo bufo
Bufo calamita
Rana dalmatina

CommonParsley Frog
European Tree
Frog
Fire Salamander Salamandra
salamandra
Alpine Newt
Ichthyosaura
alpestris
Northern
Triturus cristatus
Crested Newt
Marbled Newt
Triturus
marmoratus

Number ofponds
impacted
8 (0.31 ha)

Ratio

Offsetrequirement(number ofponds)

Terrestrial habitat requirement
OffsetTerrestrirequiremalRatio
ent (hahabitatterrestrial(ha)habitat)

4

32

3.70

1

3.70

25
1
3 (1.17 ha) 5
30 (5.42 ha) 1

25
15
30

11.76
107.061
1

11.76
107.06

2

1

2

4

4

16

12 (0.42 ha) 3

36

23.01

1

23.01

14

2

28

12

4

48

25 (0.71 ha) 4

100

42.96

1

42.96

6 (0.1 ha)

12

9.29

1

9.29

2

77

Palmate Newt

Lissotriton
30
helveticus
Smooth Newt
Lissotriton vulgaris 9
Blasius Newt
Triturus x blasii
2
Cumulated total (number)
182
On ground total (fungible foramphibians)


68

5

150

5
1
(average= 3)(average= 3.1)

452541(average= 1)(average
137.95ha= 1)
198

213 ponds

198
137.95 ha

Offset design

The design characteristics of the ponds are described in 2.1.2.
It was voluntarily decided to accompany the newly created or restored ponds with amphibian-friendly terrestrial
habitats of an average surface area of 1 hectare. In addition, 100 m of hedgerows per pond were proposed in orderto aid integration into the green and blue corridors and to promote the movement of amphibians in the landscape.
Furthermore, in order to limit the impacts on amphibians during the works, immediate compensation ponds wereconstructed/restored before the works began. The individuals present in the “to be impacted” ponds weretransferred to the new ones. These ponds share the same design characteristics as some described in paragraph 2.1.2
concerning ponds offset, but their surface is a maximum of 25 m².
These ponds are intended to support and favour the amphibian transparency structure’s efficiency. Providing ponds
on both sides of the amphibian structures (whatever their type may be) reinforces their attraction.


Offset implementation

Ponds offset

Offset requirement
213 ponds

Offset implemented
213 ponds

Terrestrial habitat offset

137.95 ha

213 haHedgerows/

21300 lm

2.7.


ReptilesProvisional impact before avoidance and reduction

Only two of the seven following protected species potentially in the route of the project were specifically inventoriedin the study area. However, given the potential use of the study area by other common protected reptilian species
and a phase of work that will inevitably result in their habitat destruction, the following species, unobserved in the
study area during inventories, may be affected:

Number of stations where it wasobserved /78

SpeciesUse Name
Aesculapian snake
Western green lizard
Common wall lizard

Latin name
Zamenis longissimus
Lacerta bilineata
Podarcis muralis

2
1
n/a

Grass snake

Natrix natrix

n/a

The slowworm

Anguis fragilis

n/aSand lizard
Western whip snake

Lacerta agilis
Hierophis viridiflavus

n/a
n/a

78



Avoidance and reduction measures

Two out of the seven species were identified as impacted by the complementary assessments. Avoidance andreduction measures are proposed for both of them.
SpeciesAesculapiansnakeWesterngreen lizard


Mitigation measures- Replantation of woods- Crossing-structures for small fauna- Protection measures in case of accidental discovery: capture or displacement with a specialized
ecologist (during spring-summer)- Reconstitution of favourable habitats (swath, scree)- Protection measures in case of accidental discovery: capture or displacement with a specialized
ecologist (during spring-summer)- Reconstitution of favourable habitats (swath, scree)

Residual impact assessment

The main wooded massifs of the regions crossed were avoided in the DPU band chosen during the preliminary studies
and then in the route’s definition during the pre-project studies, which is an important measure of avoidance.
The Western Green Lizard is not a particularly endangered species as its distribution is extensive.
The Aesculapian snake, although one of the key ZNIEFF species in Brittany and considered "declining" in the region,is common in the Pays de la Loire department. It was identified in 2 nearby sites though its habitat, resting andbreeding areas are difficult to locate. Given this and taking into account the fact that the slopes of the HSL will
constitute important habitats of predilection for the Aesculapian Snake, the project is in fact likely to maintain or
improve the conservation of the population. As it does not require important regular movements, the impacts of the
HSL on the species’ movements will also be limited.
Species

Residual impact assessment

Use Name

Latin nameLocal scale

Aesculapian snake

Zamenis longissimus

Low

Regional
scale
Low

Western green lizard

Lacerta bilineata

Low

Low

No

Common wall lizard

Podarcis muralis

None

None

No

Grass snake

Natrix natrix

None

None

No

The slowworm

Anguis fragilis

None

None

No

Sand lizard

Lacerta agilis

None

None

No

Western whip snake

Hierophis viridiflavus

None

None

No

Yes/NoNo

Therefore, no residual impact was considered, and no compensatory measures are needed.

2.8.
PlantsPotential impact before avoidance and reduction

Of the 46 plant species inventoried in the DPU band (500 m large) since 2003, seven are protected but, according to
the initial impact assessment study, only one is directly concerned by the project (Soft Hornwort—Ceratophyllum
submersum).
ERE, however, decided to conduct additional studies on two other protected species (Floating Water-Plantain andLarge Bitter-Cress) and on 14 non-protected heritage species, previously identified on the site or close to the impacted
sites.

79

The detailed inventories on the project’s footprint perimeter (including excavation and refilled areas) + 50m of buffer
area on both sides were conducted in 2011 by Dervenn and gave a better estimate of the project’s impact on theflora. The conclusion of the studies was that no non-protected species’ population were threatened by the project.
Thus, they were not taken into account in the offset requirement.
The stations and ponds close to the route, which can be impacted directly and indirectly by the project, were thus
inventoried. The 3 protected species only are shown here:
Number of stations where it wasobserved

SpeciesUse Name
Soft Hornwort
Floating Water-Plantain
Large Bitter-Cress

5 ponds
010
1 station

Avoidance and reduction measures

Species

Avoidance measures

Soft
Hornwort

Large BitterCress

Latin name
Ceratophyllum submersum
Luronium natans
Cardamine amara

Reduction measures

For the 3 not directly impacted ponds:- putting up fences to the right of the ponds to
avoid the straying of the machines- temporary sanitation to protect the ponds set
up at the start of the works (temporary
collection ditches, fine geotextile filters, straw
filters), to avoid damage to the environment
For the unique station, not directly impacted:- Installation of a secure space delimited bypoles and wires in the existing pond in order toavoid the passage of gear on the identified site.
- Prohibition of embankments and drainage
close to the site

For the 2 directly impacted ponds:- Species displacement carried out closely (tothe existing or to be created ponds), equivalentin surface, quality and durability of the level of
the water. Moving this species is compatible
with compensation measures for amphibians.

No reduction measure. The station was notdirectly impacted

Residual impact assessment

The measures avoided impact on the Soft Hornwort for three ponds and on the Large Bitter-Cress in the only habitat.
Species
Residual impact assessment
Number of
Local
Regional
Use Name
Latin name
Yes/No
ponds
scale
scale
impacted
Soft Hornwort
Ceratophyllum submersum Average
NoneYes
2 ponds
Floating WaterLuronium natans
None
None
No
Plantain
Large Bitter-Cress
Cardamine amara
None
None
No


Offset requirement

Soft Hornwort

10

Residual impact
2 ponds

Ratio*2

Offset requirement
4 ponds

The presence of this species had been noted in a station during the EIA but disappeared since and was therefore
not observed.

80

Offset design

The Soft Hornwort is threatened by the disappearance of ponds, wetlands drainage, the massive introduction ofherbivore-fish and water pollution. To compensate the residual impacts, two types of measures were implemented:
the creation and/or restoration of ponds (see ponds offset for more details).
The design of the offset ponds to be created depended on the initial Soft Hornwort station size. The average size ofthe hosting ponds was 50 to 200 m², favourable to the plant but not to fish species which prefer larger spaces.
Given that the Soft Hornwort likes eutrophic waters with few herbivore-fish and vegetation (to avoid any
competition), the objective of pond restoration was to recreate hosting potentialities bypartially dredging the ponds (to reduce the existing vegetal species),
cutting and uprooting woody
elements (to avoid habitat
closure)Electric fishing
To aid the re-colonisation of the ponds,
individuals (Figure 23) were transplanted
to the immediate compensation ponds.
The offset was implemented in eight
ponds instead of four because of the risk
factors.

Figure 23: Transfer of the Soft hornwort (Source: Eiffage)

Soft HornwortOffset requirement

Offset implementation

4 ponds

213 ponds in total, 8 pondswith species transfer

Accompanying measures

Even though residual impact for the Floating
Water-Plantain was undetected, its status in
the region is threatened; ERE thus voluntarily
decided to favour the long term conservation ofthis species with the:creation of two ponds near the ones
where the Floating Water-Plantainhad been spotted less than five years
ago with a transfer of the sedimentextracted from them (Figure 24)
restoration of two ponds where the
Floating Water-Plantain is present.

Figure 24: Transplantation of the Soft hornwort in an offset pond (Source:
Eiffage)81

Appendix 1: Synthesis of the conclusions of
the environmental impact assessment (EIA)
In terms of biodiversity, the EIA synthesized:
Species covered by the Habitats Directive, i.e., species of community interest at the European level that require strict
protection (listed in Annex II and/or IV of the Habitats Directive) and have been inventoried in or near the study
area11.
We have found:








17 species of birds
10 species of bats
3 species of invertebrates
3 species of fish
6 species of amphibians
3 species of reptiles
1 plant species

11

At the regional scale:- Two red lists exist in the Pays de la Loire: priority birds and priority mammals, amphibians and reptiles.
- There is no red list in Brittany but a list of species considered to be decisive in the designation of ZNIEFFs that shows theregional status of the conservation of species or groups of species.
 These lists have no regulatory scope but take the heritage identity into account.
From a regulations point of view, the following texts guided the offset project:- Birds: The Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on theconservation of wild birds + the Order of 29 October 2009 amending the decree of 17 April 1981 that establishes thelist of protected birds in the territory and the methods for their protection.
- Mammals: The Order of 23 April 2007 amending the decree of 17 April 1981 establishes the list of protectedmammals throughout the territory and the methods of their protection.
- Insects: The Order of 23 April 2007 amending the decree of 22 July 1993 that establishes the list of protected insects
in the national territory and the methods of their protection.
- Amphibians and reptiles: The Order of 19 November 2007 amending the decree of 22 July 1993 that establishes thelist of protected amphibians and reptiles throughout the territory and the methods of their protection- Fish and shellfish: The Order of 8 December 1988 that lists the protected fish throughout the national territory +the Order of 23 April 2008 that identifies the fish and crustacean species and the characteristic grain size of thespawning grounds.
- Crayfish: The Order of 18 January 2000 amending the Decree of 21 July 1983 on the protection of native crayfish.
- Molluscs: The Order of 23 April 2007 amending the Decree of 7 October 1992 that establishes the list of protectedmolluscs in France,- Protected plant species in France: The Order of 20 January 1982 (published in the OJ of 13 May 1982, then amended
by the Decree of 31 August 1995) which establishes the list of the protected plant species throughout the national
territory,- Protected plant species in Brittany: The Order of 23 July 1987 fixes the list of the protected plant species in Brittany
and completes the national list,- Protected plant species in the Pays de la Loire: The Order of 25 January 1993 lays down the list of protected plant
species in the Pays de la Loire region and supplements the national list.

82

1. Birds
Among the 17 species of heritage interest birds identified during the inventories, 7 are a part of the hedge landscape.
Others were: species related to wetlands (watercourses)
 two species related to wide open and cultivated areas three forest species
 a crop related species

2. Bats
According to the data transmitted by the Mayenne Nature Environment (MNE), at least 7 remarkable bats wererecorded in the study area during the winters between 1997 and 2003, particularly in the north of Laval (Argentré,
Louverné) in the Mayenne. The specific bat surveys carried out in June and September 2005 in the Erve Valley andthe southern part of the ZNIEFF in Louverné made it possible to refine the presence of bats outside of the hibernation
period.

17 bats species in the 10 protected on the 7 protected on the
study area
European scalenational or regional scale

3. Insects
Some species of entomological interest identified in or near the study areas included Odonata (dragonflies),
Orthoptera (locusts, grasshoppers, crickets) and beetles.
 Dragonflies (or Odonata): Field surveys identified 3 species of dragonflies, infrequent in the region.
 Orthoptera (locusts, grasshoppers): Field surveys identified 5 species of Orthoptera, infrequent in
the region.
 Coleoptera: Two nationally protected and regionally vulnerable species were identified.
 Lepidoptera rhopalocères (butterflies): It should be noted that no remarkable butterflies wereidentified in the areas studied nor did the local naturalist associations indicate any particularly
remarkable species. Only one species from Annex 4 of the Habitats Directive, classified as rare andvulnerable in the region, was reported on the limestone slopes of the Erve Valley. However, there
was no suitable natural habitat for this species in the areas studied.

10 protected at a 3 species of odonata
13 insects species in 3 protected at thenational or regional 5 species of orthoptera
the study area
European scale
scale
2 species of coleoptera

4. Wild fauna
3 species were identified throughout the study area.

3 species of the wild
fauna in the study area

5. FishThe Hydro biological and Fish Network (HFN) makes it possible to annually monitor the state of the fish populations
at a national level. Over the entire route, six watercourses have a monitoring station that belong to this network: in Ille-et-Vilaine: the Vilaine; in Mayenne: Oudon, Mayenne and Erve;83



in Sarthe: the Vègre and the Sarthe.

According to the data collected by the HFN and the Departmental Federations for Fisheries and the Protection of theAquatic Environment, 9 remarkable species were recorded from all the rivers that cross the study area. Beyond thespecies present, the rivers could be classified in categories of fish families present, or not, in the particular naturalenvironment of the waterway. This ranking is an indicator of the quality of the aquatic environments. Among the 73
rivers identified in the study area, sufficient information on 25 of them could characterize ecological sensitivity (18 ofthem on the inventory database and the other 7 based on specific assessments carried out in 2005). The rivers crossedby the HSL in Ille-et-Vilaine do not present a major fish challenge (no impacts were predicted). On the other hand,
the rivers were of medium to high sensitivity in the Mayenne and in the Sarthe.

9 fish species in the 3 protected atstudy area
European scale

the 73watercourses
inventoried

6. Amphibians
Seven remarkable amphibian species, determinants of ZNIEFF, were inventoried in the study area. The main axes ofamphibian movements were identified, prioritized and mapped.

13 amphibians species 6 protected onin the study area
European scale

the 7 protected on a nationalor regional scale

7. Reptiles
In total, 6 reptile species were observed throughout the study area. Two of them are of heritage interest because of
their lower regional frequency.

9 reptiles species in the 3 protected on
study area
European scale

the 6 protected on a nationalor regional scale

8. Plant species concerned by national and regional decrees
These decrees aim to "prevent the disappearance of threatened plant species and to allow the conservation of thecorresponding biotopes". They stipulate that "the destruction, cutting, mutilation, grubbing, picking or removal,
hawking, use, offering for sale, sale or purchase of all or part of the wild specimens" of the listed species are forbidden.


6 supplementary plant species

Remarkable plant species across the 3 departments with a stake in the study area bring the total number of plant
species to 43, and 36 extra species if we move to more local bylaws.

43 plants species in the 1 protected atstudy area
European scale

the 66 protected at a 36 protected atnational or regional scale departmental scalea

9. ZNIEFF type 1 or 2.
As a reminder:Type I ZNIEFFs correspond to generally small sized areas, characterized by the presence of rare or
remarkable species or environments (e.g., those that are covered by the Habitats Directive) thatare characteristic of the national or regional heritage. Very often they present protected species
stations at regional or national levels.

84





ZNIEFF types 2 are large natural complexes (forest massifs, valleys, plateaus, and estuaries) richand/or little modified by human activities, or which offer significant biological potential. Type 2
ZNIEFFs can therefore integrate one or more type 1 ZNIEFFs within their perimeter. In the study
area, 4 type 1 ZNIEFFs were identified on the route, a total of 42.41 potentially impacted hectares.
A type 2 ZNIEFF was inventoried with an area of 29.84 ha.
Cumulative total of 72.25 ha of intended impact.

4 ZNIEFFs of type 1
An area of 72.25 ha of crossed
representing
predicted total impact
42.41ha of intended
impact

1 ZNIEFF of type 2
crossedrepresenting
29.84ha of intended
impact

10. Wetlands
A number of wetlands and ponds for private use (gardens, livestock watering, irrigation) or for fishing were identified
as directly affected by the project; these wetlands are particularly suitable habitats for many species, especially foramphibians.

85

Appendix 2: Description of the predicteddirect and indirect impacts on birds
Status
Birds
Eurasianthick-knee

Montagu's
harrier
Europeanhoney buzzard

Hen harrier
Wood lark
Commongrasshopper
warbler
Commonfirecrest
Europeannightjar

Eurasianhobby

Hawfinch

12

Direct impacts

Indirect impacts

Burhinusoedicnemus

EN/CR- 18 couples, spread overthe departments ofSarthe (13 couples, i.e.,
13% of the estimateddepartment population)
Embankments > 3m =and Mayenne (5 couples,
affects bird couples
i.e., 7 to 8% of thenestsestimated department
population)- Potentially favourable
agricultural areas (cornand sunflower crops)= 85.15 ha
CircusNesting or resting sites
n/a (not applicable)CRpygargus(13.81 ha of impacted
arable field crops)
Pernis apivorus
n/a
NT
n/a

Nat.

Circus cyaneus N/a
Pullula arboré n/a
Locustellanaevia
n/a

n/a
n/a
n/a

Regulusignicapillan/aCaprimulgus
europaeus- destruction of a wood
(favourable to thespecies)14- collision with the trains- destruction offavourable habitat
Falco subbuteo- cut-off of ecologicalcorridors
Coccothraustes - destruction of hedges
coccothraustes in communication withafforestation

Nat.

I-III

Nat.

I

VU
EN/CR
EN

Nat.
Nat.
Nat.

I

n/a

LC

Nat.

II

- population decline
due to thefragmentation anddestruction of its
habitats
n/a

EN

Nat.

I

EN

Nat.

n/a

DD

Nat.

Regional status of the species on the Red List
Protection status on the national and international scale
14
For somes species, the area destroyed was not available, just the type of impact
13

Regional12 Protection13

II

86

Short-eared
owl
Sand martin
EurasianhoopoeBlackwoodpecker
Commonhouse martin
Red-backed
shrikeAsio flammeus
Riparia riparia
Upupa epops
Dryocopus
martius
Delichonurbicum
Lanius collurio

n/a

NA

n/a
n/a
- destruction of hedges
n/ain connection with otherhedges- collision with trains- collision with trainsn/a- cut-off effectn/a- Destroyed building

VU
NT

n/a

- collision with trains

n/a- Rupture of the n/a
continuities used during
Lesserthe nesting period for
Dryobates
spottedforagingminor
woodpecker
fragmentationofforestation- collision with trains- destruction of the n/a“bocage” (destruction of
Little owl
Athene noctua the habitat)- destruction of somebreeding areas- alteration of the n/a
Zitting
Cisticolafunction of ecologicalcisticola
juncidis
corridor- fragmentation of the n/a
Cetti's
habitatCettia cetti
warbler- cut-off of hunting areas,
shelters, and corridors
fragmentationof n/ahunting territories
Long-eared
destructionofAsio otus
owlhedges/ecologicalcorridorsconnecting
woods
Eurasian- reduction of the n/a
Accipiter nisus
sparrowhawk
favourable habitats
Common- cut-off of the hydraulic n/a
Alcedo atthis
kingfisher
continuity

Nat.

I-II

DD

Nat.

I

DD

Nat.

II

VU

Nat

I

VU

Nat.

LC

Nat.

III

LC

Nat.

II-IIILCNat.

II-III

VU

LC

I

87

Appendix 3: Determination of the predicteddirect and indirect impacts on bats forresidual impact estimation
Bats
Bechstein's Myotis
batbechsteinii

Direct impacts

In
direct impacts

StatusRegional Protection
DD
Nat.
II-IV

Rest and breeding lodges
Emb+ hunting areas (4,87 ha
ankment = barrierof forestation)
Barbastelle Barbastella
Impacts on resting and Impacts on hunting VU
barbastellus
wintering areas (10.75 ha territories
andof forestation)
movement corridors
CommonPlecotus auritus Resting and breeding
LC
Alteration of hunting
long-earedarea (5,83 ha) andgrounds and corridorsbatcorridors
Whiskered Myotis
Destruction of 17.46 ha
LC
Risk of collision inbat
mystacinus
of forestation (= cutting
embankment areasof the edges)
Kuhl'sPipistrellus
Birthing
shelter
VU
pipistrelle kuhlii
destroyed by the project n/a (not applicable)
11.97 haNatterer's Myotis nattereri Deforestation of 5.49 ha
DDbat= Rest and breeding Risk of collision
lodgings
Serotine
Eptesicus
0.61 haDDn/abat
serotinus
CommonPipistrellus
12.58 haDDn/apipistrelle pipistrellus

Nat.

II-IV

Nat.

II-IV

Nat.

II

Nat.

IV

Nat.

IV

Nat.

IV

Nat.

IV

88

Appendix 4: Determination of the predicteddirect and indirect impacts on insects forresidual impact estimation
StatusInsects
HermitbeetleGreatcapricornbeetleOsmodermaeremita

Direct impacts

Indirect impacts

Region ProtectialonDD
Na IIt. IV- Destruction of trees:
18 trees impacted + 8 trees withancient evidence of thepresence of the species directly
impacted by the passage of the - The impacts induced by theland development procedureroute:- The impact on dispersal and
 2
trees
on
the
movement corridors“Tricouillère” site, in- Potential impact on the
Domagné,state of conservation of the 3 trees in the “Haie dupopulation
Fontaine”
site,
in- The abandonment ofBrielles,silvopastoral practices such 2 trees on the site ofas pollarding or pruning trees"Les Cormiers", inin favour of the formation of
Coulans-sur-Gée.
habitats propitious to its
 1 tree at "Bon Accueil et development. In some sites,
La Vannerie" at thethe number of trees of thisedge of town between
type is important but they are
Coulans- sur-Gée and all the same age giving rise to
La Quinte.
thecrucial long term
- The elimination of old trees in renewal of the habitat of thisagricultural environments
species- The grooming of the forests byeliminatingthedecayedsubjects during the cuts
8 trees / 320 lm
Cerambyx - 153 trees impacted- Habitat loss as a result of VU
cerdo- 6,120 linear meters of hedges land development and theimpacted
increase in the size of
farmland (hedge clearance)
as well as current silvicultural
practices (shortening theduration of exploitation,
absence of dead or dying
trees in the forest).

Na IIt. IV

89Appendix 5: Determination of the predicteddirect and indirect impacts on semi-aquatic
mammals for residual impact estimation
Terrestrial and semiaquatic mammals
Miller's
water
shrew

Eurasian
water
shrew

Eurasian
otter

EuropeanbeaverCommondormouse

Neomysanomalus

Direct impacts

Indirect impacts

Loss of 2 types of sites for resting
and reproduction:- Surface habitats: riparian forest(3m wide), hygrophilous woodland,
water bodies and ponds and poplar
plantations = 3.99 han/a- Linear habitats: ditches, streams,
small rivers with single riparian or
narrow shrub layers less than 3 m
wide = 19,950 m= 8.07 ha in total
NeomysLoss of 2 types of sites for resting
fodiens
and reproduction:- Surface habitats: riparian forest (3m wide), hygrophilous woodland,
water bodies and ponds and poplar
plantations = 3.99 han/a- Linear habitats: ditches, streams,
small rivers with single riparian or
narrow shrub layer less than 3m
wide = 19950 m= 8.07 ha in total
Lutra lutra
Loss of 2 types of sites for resting
and reproduction:- Surface habitats: riparian forest (3m wide), hygrophilous woodland,
water bodies and ponds and poplar
n/aplantations = 3,75 ha- Linear habitats: ditches, streams,
small rivers with single riparian
forest or narrow or narrow shrub
layer less than 3 m wide = 6,103 m
Castor fiber Surface habitats: poplar
plantations, riparian forests ofalders, willows and ash trees
n/a= 1.44 haLinear habitats: on a 2 m band (427m or 0.09 ha)
Muscardinus- Fragmentation due to- Destruction of habitats
avellanarius
the intensification of- Destruction of individuals
agriculture, urbanisation

StatusReg.
DD

Protection
Nat. III

DD

Nat.

III

LC

Nat.

II-IV

EN

Nat.

II-IIIIVNT

Nat.

III-IV90- Destruction of resting andbreeding habitats
Eurasian
Sciurus
red squirrel vulgaris- Destruction of habitats

Europeanhedgehog

Erinaceus
europaeus- Destruction of habitats- Destruction of individuals- Land development- Partitioning of habitats
and populations- Fragmentation andartificialisation of thenatural habitat- breaking of ecologicalcontinuities anddisplacement corridors- Fragmentation of
habitats- Drowning- Decrease in the foodresource linked to theuse of pesticides

LC

Nat.

III

LC

Nat.

III

91

Appendix 6: Determination of the predicteddirect and indirect impacts on fish for residual
impact estimation
StatusFish

Direct impacts

Indirect impacts
Reg.

Brown
trout
(spawningground)Salmo
truttaNorthernpike

Esox
luciusBrook
lamprey

LampetraplaneriCommondace

Leuciscus
leuciscus

Amur
bitterling

Rhodeussericeus

Protection

5 potential spawning
VU
sites exclusively related
to brown trout wereidentified. 2 of themwere impacted. The n/a (not applicable)
direct impact on brown
trout spawning grounds
is estimated at 214 lm/0.05 haNo northern pike’s Indirect impacts by clogging flood- VU
spawning grounds were prone grasslands due to the loss ofidentified in the study fine particles during construction are
area.
therefore possible.
No brook lamprey’s Indirect impacts by clogging the VU
spawning grounds were banks and the bottom of the minor
identified in the study bed are therefore possible. They are,area.
in any case, difficult to quantify, oreven to highlight when too far fromthe project.
No common dace’s Indirect impacts by clogging of
spawning grounds were watercourse bottoms are therefore
identified in the study possible, although difficult to
area.
quantify, or even to highlight when
too far from the project.

Nat.

No common dace’s Indirect impacts by clogging of VU
spawning grounds were watercourse bottoms are therefore
identified in the study possible, although difficult to
area.
quantify, or even to highlight when
too far from the project.

Nat.

Nat.

Nat.

IIIV

Nat.

IIIV

92

Appendix 7: Determination of the predicteddirect and indirect impacts on amphibians forresidual impact estimation
StatusAmphibians
Natterjack
Toad

Bufo calamita

CommonToad
Edible Frog

Bufo bufo

Agile Frog

Pelophylax
esculentus
Ranadalmatina

European
Tree Frog

Hyla arborea

Fire
Salamander
Northern
Crested
Newt

Salamandra
salamandra
Trituruscristatus

MarbledNewt

Triturus
marmoratus

Direct impacts

Indirect impacts

Regional

Aquatic
habitats:
EN
breeding area (3 bodies ofwater in old gravel pits)(1.17ha)n/a (not applicable)- Terrestrial habitats: open
and sandy environments(gravel and pebble areas)(11.76 ha)- fragmentation of the LC
27 ponds and water bodies
habitats
DD
2 ponds impacted
n/a
30 ponds and water bodies:- breeding areas: aquatic
habitats (5.42 ha)- resting areas: terrestrial
n/ahabitats= 107.06 ha(forestation (38.2 ha),hedgerows (38.63 ha) andwetlands (30.23 ha)
12 impacted ponds:- breeding areas: aquatic
habitats = 0.2ha- resting areas: terrestrial
n/ahabitats=
23
ha(forestation
5.63
ha,hedgerows 14.89 ha andwet meadows 2.49 ha)
14 ponds

n/a

25 ponds:- terrestrial habitats: rest
(42.69 ha) = hedges (14.58ha), forestation (15.07 ha),n/a
wet meadows (13.04 ha)aquatic
habitats:
reproduction (0.71 ha).
Deep ponds
28 ponds:- terrestrial habitats: rest n/a(9.29 ha)Protection
Nat.

IV

Nat.

III

Nat.

III-IV

LC

IV

LC

Nat.

II-IV

LC

Nat.

III

VU

Nat.

II-IV

EN

Nat.

IV

93

- aquatic habitats: 0.10 haPalmateLissotriton
Newt
helveticus
Alpine Newt Ichthyosaura
alpestris
SmoothLissotriton
Newtvulgaris
CommonAlytesMidwifeobstetricans
Toad

CommonPelodytes
Parsley Frog punctatus

6 ponds impacted

n/a

12 ponds impacted

n/a

9 ponds impacted

n/a

8 ponds impacted- breeding areas (aquatic
habitats = 0.31 ha)n/a- rest areas (terrestrial
habitats = 3.7 ha)
5 ponds impacted

n/a

LC

Nat.

II

NT

Nat.

III

NT

Nat.

III

VU

Nat.

IV

VU

Nat.

94

Appendix 8: Determination of the predicteddirect and indirect impacts on reptiles forresidual impact estimation
ReptilesAesculapiansnakeWesterngreen lizard

Zamenislongissimus
Lacertabilineata

Direct impacts

Indirect impactsn/a (not applicable)

Impactsondisplacements

n/a

n/a

StatusRegional Protection
the Vulnerable Nat. II-IV
Quite
CommonNat.

III-IV95

Appendix 9: Methodology of the descriptionof the hedges
1. Location of the hedges
A census of the linear of hedges was made by photo interpretation.

2. Characterization of the hedge (method developed for the project)
2.1.





2.2.












Typology of hedges according to their position in the landscape and/or land
form
Presence of an embankment
Presence of a ditch
Hedge located at the boundary of the parcel
Cutting regime (frequency at which it is cut)Composition of the hedge
Nature of strata
Age of subjects
o Less than 20 years
o 20 to 50 years of age
o 50 to 100 years of age
o Over 100 years
Densityo 1: very low
o 2: lowo 3: averageo 4: dense
Number of rows
Thickness of the hedge
Characterization of the species (covering rate)o 1st class: the species covers less than 10% of the hedge (minority species)o 2nd class: the species covers from 10 to 50% of the hedge (well represented species)o 3rd class: the species covers from 50 to 75% of the hedge (very represented species)o 4th class: the species covers from 75 to 100% of the hedge (dominant species)
Sanitary state (are the subjects ill or attacked by pests)
Presence of cavities

96

Appendix 10: Methodology of the descriptionof the wetlands
The wetland habitats were described in 2011 by Asconit, a design consultancy specialized in these types of studies.

1. Hydrological descriptors
The parameters related to hydrology taken into account during the field diagnoses were: the frequency and extent of the submergence of the wetland parcel
 the inflow and outflow of water observed, as well as their permanence the identification of the hydraulic functions ensured by the parcel and their level of interest
 the identification of potential purifying functions
 an overall assessment of the hydrological functioning

1.1.

The descriptors of the purifying functions

The purifying functions of wetlands can be dissociated according to the biological and physical criteria they present.
These criteria make it possible to define the capacity of the wetlands to intercept suspended matter (physicalcriterion) and to regulate nutrients (biological criterion).

1.2.

The descriptors of biology

The biological data consists of lists of the species of the plants and animals present and observed on site during thefield visit. The biological diagnosis was determined by identifying the biological functions associated with a value
highlighting the interest of the wetland with regard to this function.
Five main functions were chosen to be identified in the field:
 ecological corridor
 feeding, breeding and reception area for wildlife
 biodiversity support
 heritage interest of a species or habitat
 carbon storage
The values of each function were evaluated based on the operator's field observations.

1.3.

Descriptors of context (use & socio-economic activity)

The context of the location of the wetland was described by identifying the activities present in and around thewetland. Their qualification was established by associating them with a level of interest.
However, the descriptors “uses and socio-economic activities” were not considered in the prioritization of thewetlands.

1.4.

Descriptors of disturbances in the area

The identification of the disturbances on the wetlands makes it possible to perceive the alterations already present
in the territory. This analysis made it possible for the project owner to add additional elements to the strategic choices
to be made in the methods of how the work is carried out and which conservation or corrective measures must be
put into place. This data is a diagnostic element linked to hydrology, biology and the state of conservation. However,the disturbance descriptors were not considered in the prioritization of wetlands.

97

Purifying functions

Hydraulic functions

Function

MediumHigh

Limited area and/or
isolated wetland

Medium area andmarked hydromorphy

Large area and stronghydromorphy (seepage
observation)

Absence of a flood
expansionzoneorinappropriate
topography

Limited surface
inappropriate
topography

Average surface andfavourable
topography

Large surface and very
favourable topography

Erosionprotection

Vegetablecoverorunsuitable positioning

Adapted plant cover andlimited surface

Adapted plant cover,positioningor
favourable surface

Storageofsurface water

Unsuitable plant cover

Adapted plant cover andsteep slope

Adapted plant coverand low slope

Reduced surface andweak hydromorphy

Medium to strong
wetland area and/or
marked hydromorphy

Adapted plant cover,favourable positioning
and surface
Adapted plant coverand very dense andzero slope
Very large wetland area
andstronghydromorphy

Limited vegetation cover
and/or area with low flow
storage capacity

Adapted plant cover
and/orfavourable
flow storage capacity

Adapted plant coverand favourable storage
area

Limited vegetation cover
and/orunfavourable
positioning

Plant cover adapted
and/orfavourable
positioning

Insufficient(riparian strip)

Naturalregulation offloodsGroundwater
recharge
Regulation ofnutrients
Interceptionof M.E.S.

Feeding area,
breeding andhomeforwildlife

Carbonstoragesurface

Inadequate surface andverylittlemarkedhydromorphy
Absence of vegetation
cover (cultivated area)
and/or lack of flow
storage capacity
Vegetable cover absent(cultivated area) and/or
inappropriate
positioning

The area does not host
reproduction or feeding

The area does notpresent a habitat that is asource of biodiversity

Biodiversity
support

Heritageinterest
species
habitat

Low

The area does not hostwetland flora or fauna
and is not a transitionzone within a network ofplots

EcologicalCorridor

Biological functions

No

Naturalsupportoflow waterofor

Absence of a species or
heritage habitat

Zone without organic
matter storage capacityandSome wetland plant
species but a weaktransition zone within a
network of plots (riparian
forest, grassed strip)

A habitat that can host
reproduction or feedingof a group of species(birds,amphibians,
mammals, insects, etc.)

The area has a habitatthat
increases
biodiversity very slightly(some plant species)

Diversewetlandhabitat but a weaktransition zone withina network of parcels(riparian
forest,grassed strip)
A habitat that can
providereception,
reproductionorfeeding of two tothreegroupsofspecies(birds,amphibians,
mammals,
insects,etc.)
The area supports a
habitat that increases
the number of plant
and animal species

Adapted plant coverandfavourable
positioning
A diverse wetland
habitat. It ensures thetransition with otheradjacent parcels

A habitat that can
providereception,
reproduction
andfeeding of more than
three species groups(birds,amphibians,
mammals, etc.)
The area supports a
habitat that greatly
enhances
local
biodiversity

Presence of some speciesof patrimonial interest

Presence of heritage
species over a large
area

Presence of many
species within a large
area or habitat with ahigh heritage value

Area with low storage
capacity:
herbaceous
vegetation cover (reedbeds) or exploited poplar

Zone
with
accumulationoforganic matter in aforest environment

Zone
with
strongaccumulation of organic
matter(marshysaussaie, peat bog, etc.)

98

As a result of all these indicators and scores, the wetlands are classified in 4 levels:
Level 1: the best level in terms of functionalities (score between 36 and 26)
Level 2: good level in terms of functionalities (score between 25 and 16)
Level 3: low level in terms of functionalities (score between 15 and 9)
Level 4: bad level in terms of functionalities (score between 8 and 5 = low and score between 4 and 1 = very low)
Level 1
Level 2
Level 3
Habitats
1. Classification
Classification(described in theaccording to the→ Wetland habitat
according tothdecree of 24
cumulative scores
cumulative scores
June 2008)of the functionsof the functions(other habitats)observed
observed↓
2. (16 > score ≥ 9)(score > or = to 16)→→2.
Functions↓Level 4
Cumulative scores
between 0 and 8

99

Appendix 11: Methodology of the descriptionof the ponds and water bodies
1.1.

Descriptors of morphology

Different sizes were identified to describe the morphology of the ponds and bodies of water: Average and maximum depth, Length and width, Slope of the banks
 Nature of the contour (concrete or stone, bare or vegetation)
 Observation of a filling

1.2.

Hydrological descriptors

The parameters related to hydrology taken into account during the field diagnosis, were: the inflow and outflow of water observed, as well as their permanence an overall assessment of the hydrological functioning
 the census of associated hydraulic structures

1.3.

The descriptors of biology

The biological data consists of lists of plant and animal organisms observed on the spot. They were supplemented by
the amphibian input data processed by Dervenn and the National Forest Office in 2011.

1.4.

The descriptors of the context

The contexts of the pond or bodies of water were described by identifying the activities present in and around them.
Their qualification has been established by associating them with a level of interest.
The identification of the attacks on the pond or the water bodies made it possible to perceive the alterations alreadypresent on the territory. This analysis made it possible for the project owner to add additional elements to thestrategic choices to be made in the methods of how the work is carried out and which conservation or corrective
measures must be put into place.

1.5.

Functional score calculation

The ranking of ponds and water bodies is based on the combination of the number of species observed with theaquatic vegetation density surveys.
The priority criterion is the "number of amphibian species"; the "aquatic vegetation density" criterion is secondary as
it modulates the levels of hierarchy that take the habitats constituted by the aquatic vegetation into account.

100

Level 1 corresponds to the sites for which:the number of species encountered is greater than 5, orthe number of species encountered is between 3 and 5 and with a density of strong to very strong aquaticvegetation.
Level 2 corresponds to the sites for which:the number of species encountered is between 3 and 5 and with zero to medium aquatic vegetation density,orthe number of species encountered is less than 3 and with a medium to very high aquatic vegetation density.
Level 3 corresponds to sites with a species count of less than 3 and a medium to low aquatic vegetation density.
By default, all ponds and water bodies without amphibian data were ranked in level 3.
Each function is characterized by a by level of interest and with a score value.
The cumulative scores of all 12 functions (listed in the table below) determine the overall functional score value ofeach zone. The maximum potential value for a wetland is 36 (Level 1). It is based on the following three main functions(on the left of the table):
Hydraulic functions
No
Low
MediumHigh
Purifying functions
1
2
3
0
Biological functions

Number of species<3

From 3 to 5

>5

Density of aquatic vegetation
Low
MediumHigh
Low
MediumHigh
Low
Medium
High

Level
3
2
2
2
2
1
1
1
1

101

Purifying functions

Hydraulic functions

Function

No

High

Limited area and/or
isolated wetland

Mediummarkedhydromorphic area

Large
and
stronghydromorphic area (seepage observation)

Average surface andfavourable
topography
Adapted plant cover,positioningor
favourable surface
Adapted plant coverand low slope
Medium to strong
wetland area and/or
marked hydromorphy

Insufficient(riparian strip)

Naturalregulation
floodsAbsenceofflood
expansionzoneorinappropriate topography

Limited surface
inappropriate
topography

Erosionprotection

Vegetablecoverorunsuitable positioning

Plant cover adapted,
limited surface

Storageofsurface water

Unsuitable plant cover

Adapted plant coverand steep slopeof

Groundwater
recharge
Regulation
nutrientsofInterception
M.E.S.

of

Feedingarea,
breeding
andhome for wildlife

Biodiversity
support

Heritage interestof species or
habitatCarbon storage

surfaceMediumNatural supportof low water

EcologicalCorridor

Biological functions

Low

Inadequate surface andverylittlemarkedhydromorphy
Absence of vegetablecover (cultivated area)
and/or lack of flow storage
capacity
Vegetable cover absent(cultivated area) and/or
inappropriate positioning

The area does not hostwetland flora or fauna andis not a transition zone
within a network of plots

The area does not allow
host, reproduction or
feeding

The area does not present
a habitat that is a source of
biodiversity

Absence of a species or
heritage habitat

Zone without organic
matter storage capacity

andReduced surface andweak hydromorphy
Limitedvegetation
cover and/or area low
flow storage capacity

Adapted plant cover
and/orfavourable
flow storage capacity

Limitedvegetation
cover
and/orunfavourable
positioning

Plant cover adapted
and/orfavourable
positioning

Some wetland plant
species and constitutes
a weak transition zone
within a network ofplots (riparian forest,
grassed strip)
The habitat can provide
eitherhosting,
reproductionorfeeding for a group of
species(birds,amphibians, mammals,
insects, etc.)

A diverse wetland
habitat. But a weaktransition zone withina network of parcels(riparian
forest,grassed strip)The
habitatcanprovidereception,
reproductionorfeeding for two tothreegroupsofspecies(birds,amphibians,
mammals,
insects,etc.)

Large surface and very
favourable topography
Adapted plant cover,favourable positioning
and surface
Adapted very dense plant
cover and zero slope
Very large wetland areaand strong hydromorphy
Adapted plant cover andfavourable storage area

Adapted plant cover andfavourable positioning

A diverse wetland habitatthat
ensuresthetransitiontootheradjacent parcels

The habitat can provide
reception, reproduction
and feeding for more
than
three
speciesgroups(birds,amphibians, mammals,
etc.)

The area has a habitatthat
increases
biodiversity
veryslightly (some plant
species)

The area supports a
habitat that increases
the number of plant
and animal species

Occasional presence ofsomespeciesofpatrimonial interest

Presence of heritage
species over a large
area

Presence of many species
in a large area or habitatwith a high heritage
value

Area with low storage
capacity: herbaceous
vegetation cover (reedbeds) or exploited
poplarZone
withaccumulationoforganic matter in aforest environment

Zone
with
strongaccumulation of organic
matter (marshy saussaie,peat bog, etc.)

The area supports a
habitat that greatly
enhances
local
biodiversity

102

Appendix 12: Indicators of the potentially
impacted water flow zones
4 indicators defined the water flow zones:-

A “physical” description of the water flow: width, substrate, facies, morphology, and presence of hydraulicworks on the bed.
Identification of land use, pollution and alterations.
Ecological description: aquatic vegetation, riparian, presence of aquatic organisms, and presence of
spawning grounds.
Identification and description of hydraulic structures.

103

Appendix 13: principles, criteria
indicators: an illustrated chronology

and104