1.

EU environmental law provides for a number of environmental assessments. Of particular relevance in the case of individual projects are the environmental impact assessment under the EIA Directive ( 2 ) and the appropriate assessment of implications for the conservation objectives of protected areas under the Habitats Directive. ( 3 )

2.

The present request for a preliminary ruling, which has its origin in the approval of a ring road round Kilkenny, Ireland, gives the Court an opportunity to clarify the substantive requirements applicable to those assessments, in particular as regards the species affected by a project and the assessment of alternatives.

3.

The questions concerning the treatment of alternatives in the environmental impact assessment are particularly problematic, although all answers to the questions referred are capable of making a valuable contribution to legal certainty in the conduct of those two assessments.

4.

Article 1(e) of the Habitats Directive defines the conservation status of a natural habitat as follows:

‘the sum of the influences acting on a natural habitat and its typical species that may affect its long-term natural distribution, structure and functions as well as the long-term survival of its typical species within the territory referred to in Article 2.

The conservation status of a natural habitat will be taken as “favourable” when:

and

5.

Article 2(2) and (3) of the Habitats Directive sets out the objectives essential to its application:

‘(2)   Measures taken pursuant to this Directive shall be designed to maintain or restore, at favourable conservation status, natural habitats and species of wild fauna and flora of Community interest.

(3)   Measures taken pursuant to this Directive shall take account of economic, social and cultural requirements and regional and local characteristics.’

6.

The assessment of plans and projects is regulated as follows in Article 6(3) of the Habitats Directive:

‘Any plan or project not directly connected with or necessary to the management of the site but likely to have a significant effect thereon, either individually or in combination with other plans or projects, shall be subject to appropriate assessment of its implications for the site in view of the site’s conservation objectives. In the light of the conclusions of the assessment of the implications for the site and subject to the provisions of paragraph 4, the competent national authorities shall agree to the plan or project only after having ascertained that it will not adversely affect the integrity of the site concerned and, if appropriate, after having obtained the opinion of the general public.’

7.

In accordance with Article 7 of the Habitats Directive, Article 6(2) to (4) are also to apply to the special protection areas that were provided for in Article 4 of the Birds Directive. ( 4 )

8.

The essential content of the environmental impact assessment is laid down in Article 3 of the EIA Directive:

‘The environmental impact assessment shall identify, describe and assess in an appropriate manner, in the light of each individual case and in accordance with Articles 4 to 12, the direct and indirect effects of a project on the following factors:

9.

Article 5(1) and (3) of the EIA Directive lays down the information to be supplied by the developer:

‘1.   In the case of projects which, pursuant to Article 4, are to be made subject to an environmental impact assessment in accordance with this Article and Articles 6 to 10, Member States shall adopt the necessary measures to ensure that the developer supplies in an appropriate form the information specified in Annex IV inasmuch as:

2.   …

3.   The information to be provided by the developer in accordance with paragraph 1 shall include at least:

10.

Annex IV to the EIA Directive sets out in detail the information to be provided in accordance with Article 5, in particular as regards the alternatives and specific environmental effects to be examined:

‘2.   An outline of the main alternatives studied by the developer and an indication of the main reasons for his choice, taking into account the environmental effects.

3.   A description of the aspects of the environment likely to be significantly affected by the proposed project, including, in particular, population, fauna, flora, soil, water, air, climatic factors, material assets, including the architectural and archaeological heritage, landscape and the interrelationship between the above factors.’

11.

Recital 13 of the EIA Directive refers to the scoping procedure provided for in Article 5(2) of the EIA Directive:

‘It is appropriate to lay down a procedure in order to enable the developer to obtain an opinion from the competent authorities on the content and extent of the information to be elaborated and supplied for the assessment. Member States, in the framework of this procedure, may require the developer to provide, inter alia, alternatives for the projects for which it intends to submit an application.’

12.

An Bord Pleanála (The Planning Board) is the body competent in Ireland for granting development consent for proposed road construction projects and, as part of that process, for determining the scale of the environmental impact assessment necessary and providing advice based on the information provided to it.

13.

In 2008, the developer, Kilkenny County Council, submitted to An Bord Pleanála an application for approval of a road construction project involving the construction of a new road and a bridge over the River Nore, as well as for the compulsory purchase of the land needed for the project. The purpose of the bypass road is to complete a full ring road around the city of Kilkenny and thereby, inter alia, to reduce traffic congestion in the inner city. The proposed road cuts through a number of protected natural areas: the River Nore Special Protection Area (‘River Nore SPA’) designated under the Birds Directive (Natura 2000 Code: IE0004233); a candidate Special Area of Conservation (SAC) under the Habitats Directive, that is to say the ‘River Barrow and River Nore SAC’ (Natura 2000 Code IE0002162); and a proposed National Heritage Area (NHA).

14.

On 11 July 2014 An Bord Pleanála made a decision approving the proposed road construction project known as the Kilkenny Northern Ring Road Extension and the compulsory purchase order. The applicants ask the Irish High Court to review that decision and to annul it on the ground that it infringes EU law.

15.

In those proceedings, the High Court, on 4 May 2017, decided to submit to the Court of Justice a request for a preliminary ruling, which was received at the Court on 28 July 2017 with the following questions:

16.

Written observations were submitted by Mr Holohan and the other applicants in the main proceedings, An Bord Pleanála, Ireland, the Czech Republic, the United Kingdom of Great Britain and Northern Ireland and the European Commission. The Czech Republic did not, however, attend the hearing on 16 May 2018.

17.

Below, I shall begin by answering the questions concerning the Habitats Directive and then reply to the questions concerning the EIA Directive.

18.

The questions concerning the Habitats Directive have to do, first, with the extent of the assessment provided for in Article 6(3) of the Habitats Directive (see, in this regard, section 1), next, with the decision-making powers which may be delegated to the developer following the approval of a project under that provision (see, in this regard, section 2) and, finally, with the requirements applicable to consent for a project with respect to the stating of reasons (see, in this regard, section 3).

19.

The first three questions referred by the High Court have to do with the extent of the assessment provided for in Article 6(3) of the Habitats Directive. The High Court asks, in particular, whether certain information must be set out in a Natura impact statement.

20.

The Habitats Directive does not, however, prescribe any particular method for carrying out such an assessment ( 5 ) and certainly does not lay down any specific requirements in respect of the Natura impact statement provided for in Irish law. Moreover, An Bord Pleanála submits that, in addition to the aforementioned document, other submissions and observations are presented, all of which must be taken into account as part of the assessment under Article 6(3) of the directive.

21.

In answering those questions, the Court can nonetheless make clear what requirements are to be applied to an assessment under Article 6(3) of the Habitats Directive.

22.

By the first question, the High Court wishes to ascertain whether the assessment provided for in Article 6(3) of the Habitats Directive must identify all the habitats and species on account of which the area was included on the list of areas of Community importance. The background to this question is that various species and habitat types in the interests of whose protection the area at issue was designated as being of Community importance are not mentioned in the documents submitted for the purposes of the assessment.

23.

I shall now show that, while the assessment must unequivocally rule out any significant adverse effects on any of the protected habitat types and species in the area in question, that can also be implied.

24.

Article 6 of the Habitats Directive contains a whole series of specific obligations and procedures designed, as is clear from Article 2(2) of that directive, to maintain at, or as the case may be restore to, a favourable conservation status natural habitats and species of wild fauna and flora of interest for the European Union. ( 6 )

25.

For that purpose, Article 6(3) of the Habitats Directive establishes an assessment procedure intended to ensure, by means of a prior examination, that a plan or project not directly connected with or necessary to the management of the site concerned, but likely to have a significant effect on it, is authorised only to the extent that it will not (in fact) adversely affect the integrity of that site. ( 7 )

26.

In accordance with the first sentence of Article 6(3) of the Habitats Directive, such plans or projects are to be subject to an appropriate assessment of their implications for that site in view of the site’s conservation objectives, if it cannot be excluded, on the basis of objective information, that they will have a significant effect on that site, either individually or in combination with other plans or projects. ( 8 ) In that connection, all aspects of the plan or project which can affect the conservation objectives of the site must be identified in the light of the best scientific knowledge in the field. ( 9 ) In particular, that assessment must be made in the light of the specific characteristics and environmental conditions of the site concerned by such a plan or project. ( 10 )

27.

Where a plan or project is likely to undermine the protected site’s conservation objectives, it must be considered to be likely to have a significant effect on that site. ( 11 ) In order for the integrity of a site as a natural habitat not to be adversely affected for the purposes of the second sentence of Article 6(3) of the Habitats Directive, the site needs to be maintained at a favourable conservation status. This entails the lasting preservation of the constitutive characteristics of the site concerned that are connected to the presence of a natural habitat type whose preservation was the objective justifying the designation of that site in the list of sites of Community interest, in accordance with the directive. ( 12 ) The same must apply, mutatis mutandis, to protected species.

28.

As the Czech Republic rightly submits, the effects on certain habitat types and species referred to in Annexes I and II to the Habitats Directive, and on migratory birds and birds referred to in Annex I to the Birds Directive, which are present on the protected site but are not covered by its conservation objectives do not, on the other hand, in principle, have to be assessed. However, this only applies if these occurrences are so insignificant that they do not for the sake of completeness have to be included in the conservation objectives of the area.

29.

Finally, the assessment provided for in the first sentence of Article 6(3) of the Habitats Directive must be free of lacunae. It must contain complete, precise and definitive findings capable of removing all reasonable scientific doubt as to the effects of the works proposed on the protected site concerned. ( 13 ) Moreover, an assessment of the implications of a plan or project for the protected site’s conservation objectives is not ‘appropriate’, within the meaning of the first sentence of Article 6(3) of the Habitats Directive, where updated data concerning the protected habitats and species is lacking. ( 14 )

30.

The assessment must therefore unequivocally demonstrate why the protected habitat types and species are not adversely affected. In this regard, it may in certain cases be sufficient to find that only certain protected habitat types and species are present at the locations concerned, which is to say that other protected habitat types and species on the site are not present at those locations. It must also be apparent from the assessment, however, that the works at the locations concerned are not capable of adversely affecting those other habitat types and species, in so far as they are present at other locations on the site.

31.

Mere silence in respect of certain habitat types or species, on the other hand, will not generally amount to complete, precise and definitive findings capable of removing all reasonable scientific doubt as to the effects of the works under assessment.

32.

The answer to the first question must therefore be that, although the assessment provided for in Article 6(3) of the Habitats Directive need not expressly identify all the habitat types and species on account of which the site was included on the list of sites of Community interest or is protected as a special protection area under the Birds Directive, it must at least implicitly contain complete, precise and definitive findings capable of removing all reasonable scientific doubt as to the effects of the works under assessment on the protected habitat types and species.

33.

By the second question, the High Court wishes to clarify whether the Habitats Directive requires that the potential impact on all species (as opposed to only protected species) which contribute to and are part of a protected habitat must be identified and discussed in an assessment under Article 6(3) of the Habitats Directive.

34.

As I have already said, ( 15 ) the requirements applicable to such an assessment will depend on the site’s conservation objectives, that is to say, first and foremost, the protected species and habitat types. It may nonetheless be necessary for the assessment to include adverse effects on other species and habitats.

35.

Other species are relevant to the assessment in any event, to the extent that they form part of protected habitats. As Mr Holohan and the other applicants in the main proceedings have remarked, this is laid down in the definition of a natural habitat’s conservation status in Article 1(e) of the Habitats Directive. The conservation status expressly includes the typical species of the habitat concerned. Any adverse effects on those species at the locations occupied by that habitat type would also attach to the habitat type concerned.

36.

The Habitats Directive provides only a rudimentary definition of the species that are typical of certain habitat types, since these are to some extent apparent from the descriptions of the habitat types in question, which often refer to particular plant species. Thus, the priority habitat type ‘Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae)’ (Natura 2000 Code 91E0*), which is present in the future SAC concerned, contains in its very own name the common alder (Alnus glutinosa) and common ash (Fraxinus excelsior), as well as bird cherry (Prunus padus), grey alder (Alnus incanae) and white willow (Salix alba).

37.

Scientific research and discussion of the different habitat types should make it possible to identify further typical species. The Commission’s Interpretation Manual of Habitats, referred to in Annex I to the Habitats Directive, ( 16 ) contains valuable guidance in this regard, although it is obviously not legally binding.

38.

Under the aforementioned habitat type 91E0*, the Interpretation Manual refers not only to the tree species immediately apparent from the habitat type designation but also to the black poplar (Populus nigra), the brittle willow (Salix fragilis), the white birch (Betula pubescens), the wych elm (Ulmus glabra) and almost 20 herbaceous layer species.

39.

It should be noted here that the species typical of protected habitat types are not confined to plant species. Thus, in connection with the habitat type ‘Estuaries’ (Natura 2000 Code 1130), which is also part of the future SAC but is presumably not affected by the project at issue, the Commission’s Interpretation Manual mentions invertebrate benthic communities (such as mussels and snails and many other small species of fauna), as well as the fact that this habitat type includes important feeding areas for many birds. ( 17 )

40.

In addition, habitat types and species which are not expressly protected may also play an essential role in the conservation of protected habitat types and species. The Czech Republic rightly refers in this regard to the importance of habitat types and species which are not expressly protected to the nutrition of protected species, although the former may also perform other functions in the life cycle of protected species.

41.

The fact that certain habitats may be of major importance to the reproduction of species is probably well known. Thus, it is essential that rivers and streams are passable if migratory fish such as salmon (Salmo salar) are to be able to reach their spawning grounds.

42.

What is more, the life cycle of certain protected species is to some extent also dependent on very specific other species. Thus, the larvae of the freshwater pearl mussel (Margaritifera margaritifera) and the endemic River Nore freshwater pearl mussel (Margaritifera durrovensis), both of which are present in the future SAC concerned, live for a time as parasites in the gills of river trout (Salmo trutta fario) or salmon. ( 18 )

43.

This does not, of course, mean that adverse effects on the typical species of protected habitat types and on other relevant species and habitats are necessarily to be regarded as adversely affecting the conservation objectives of the protected site in such a way as to preclude the plan or project. Adverse effects of such kinds preclude the project only to the extent that they create reasonable scientific doubt concerning the proposition that they will not adversely alter the conservation status of the protected habitat types and species on the site in question.

44.

Consequently, the assessment provided for Article 6(3) of the Habitats Directive appropriately covers effects on a site’s conservation objectives only if it includes the adverse effects both on the typical species of the protected habitat types and on other species and habitat types to the extent that these are necessary to the conservation of the protected habitat types and species.

45.

By the third question, the High Court wishes to ascertain whether an assessment under Article 6(3) of the Habitats Directive must expressly address the effects of the proposed project both on protected species and habitats located in the protected area and on species and habitats located outside its boundaries.

46.

Mr Holohan and the other applicants in the main proceedings point in this regard to Article 2(3) of the Habitats Directive. According to that provision, measures taken pursuant to that directive are to take into account, inter alia, regional and local characteristics. For the purposes of the assessment of potential adverse effects on the site, this means that the latter cannot be assessed in isolation from the area surrounding the site and the characteristics of that area.

47.

The Court of Justice also has already recognised that activities carried on outside protected areas which give rise to adverse effects within those areas must also be assessed under Article 6(3) of the Habitats Directive. ( 19 ) In this regard, the judgment concerning the Moorburg power plant, in particular, is of interest in the present proceedings. This concerned the possible killing, as a result of the facility for cooling the power plant in question, of fish for the reproduction of which protected areas had been established upstream. Since, because of the power plant, there was a risk that fewer fish would reach those areas, the power plant project in question adversely affected the integrity of the protected areas.

48.

Equally important from the point of view of assessment under Article 6(3) of the Habitats Directive are the adverse effects on species outside the future SAC or SPA, where these are either protected species themselves or are species typical of protected habitats, or where they are in some other way necessary to the conservation of protected habitats and species.

49.

Furthermore, adverse effects on habitats outside protected areas may also be important. This is the case in particular where a protected area, although protecting specific species, does not include all the habitats used by those species. In that event, any degradation of such habitats arising outside the protected areas could adversely affect the protected presence of species within those protected areas.

50.

Nor would I wish to rule out the possibility that, from a scientific point of view, certain interactions may be identified as a result of which adverse effects on habitats outside protected areas are detrimental not only to species but also to habitats within protected areas.

51.

Whether the habitats outside the protected areas are habitat types listed in Annex I to the Habitats Directive, on the other hand, seems irrelevant at first sight, since habitats listed in Annex I are, as such, protected in principle only within the protected areas.

52.

The assessment provided for in Article 6(3) of the Habitats Directive must therefore also include adverse effects on species or habitats outside the protected areas, where such adverse effects may be detrimental to the conservation objectives of the protected areas.

53.

The eighth question seeks to ascertain whether it is compatible with the Habitats Directive for details of the construction phase (such as the compound location and haul routes) to be left for post-consent decision, and, if so, whether it is open to a competent authority to permit such matters to be determined by unilateral decision of the developer, in this instance Kilkenny County Council, within the context of any development consent granted, to be notified to the competent authority, that is to say An Bord Pleanála, rather than approved by it.

54.

In accordance with Article 6(3) of the Habitats Directive, the competent national authorities must agree to the plan or project only after having ascertained that it will not adversely affect the integrity of the site concerned.

55.

The assessment provided for in the first sentence of Article 6(3) of the Habitats Directive must therefore be free of lacunae. It must contain complete, precise and definitive findings capable of removing all reasonable scientific doubt as to the effects of the works on the protected site concerned. ( 20 )

56.

Consequently, a developer may only be left to make decisions in respect of which there is no reasonable scientific doubt that their effects will be non-detrimental to the site concerned.

57.

Such doubt may in particular be ruled out by sufficiently specific conditions of consent which lay down for those decisions a framework of such a kind as to ensure that they are not capable of adversely affecting the integrity of the site concerned.

58.

Whether those requirements are satisfied in the case in the main proceedings is a question which the national court must examine in the light of the specific circumstances of the development at issue.

59.

If a comprehensive assessment of the conditions relating to details of the construction phase is not yet possible at the time of the approval in principle of the plan or project, a multi-stage assessment and consent procedure must be conducted, as the Czech Republic notes. This is the approach taken in the context of environmental impact assessments. ( 21 )

60.

The answer to the eighth question must therefore be that, in the context of a development consent granted under Article 6(3) of the Habitats Directive, details of the construction phase may be left to unilateral decision of the developer only where every reasonable scientific doubt that the effects of such a decision will not be detrimental to the integrity of the site concerned has been dispelled.

61.

By the ninth, tenth and eleventh questions, the High Court seeks to ascertain what requirements govern the reasons to be stated for a decision under the second sentence of Article 6(3) of the Habitats Directive, in particular whether the decision-making authority must expressly dispel specific doubts about whether the information available is sufficient.

62.

From the point of view of EU law, these questions leave room for misunderstanding, inasmuch as the statement of reasons required by the second paragraph of Article 296 TFEU must disclose in a clear and unequivocal fashion only the reasoning followed by the institution which adopted the measure in such a way as to enable the persons concerned to ascertain the reasons for it and to enable the competent court to exercise its power of review. ( 22 ) That is not what is at issue here, however.

63.

The dispute in the national proceedings is, rather, whether the reasons given are sufficient to justify the decision of An Bord Pleanála. After all, as the parties to the proceedings unanimously point out, a plan or project may be approved under Article 6(3) of the Habitats Directive only where the assessment of the development contains complete, precise and definitive findings capable of removing any reasonable scientific doubt as to the effects of the works proposed on the protected site concerned. ( 23 ) Considered as a whole, therefore, that assessment must show with sufficient detail and clarity that every reasonable scientific doubt has been dispelled.

64.

In this connection, Ireland rightly draws a comparison with the case-law on the EIA Directive to the effect that, under that directive, although decisions do not themselves have to contain any reasons, if an interested party so requests, the competent administrative authority is obliged to communicate to him the reasons for the relevant decision or the relevant information and documents in response to the request made. ( 24 )

65.

This also applies to decisions on the basis of Article 6(3) of the Habitats Directive, in so far as this provision, too, does not prescribe any particular form for the approval of a development, but confines itself to requiring an appropriate assessment. It is therefore possible, instead of giving express reasons for a decision, to refer to the evidence presented in the assessment of the proposed development’s implications for the conservation objectives of the site concerned. It must be pointed out, however, that this approach must not have the effect of jeopardising the effective judicial protection of the interested parties. ( 25 )

66.

Against that background, the individual questions can be answered relatively straightforwardly.

67.

The ninth question seeks to clarify whether a competent authority is obliged to record, with sufficient detail and clarity to dispel any doubt as to the meaning and effect of such opinion, the extent to which scientific expert opinion presented to it argues in favour of obtaining further information prior to the grant of development consent.

68.

Whether such an obligation exists depends in essence on the clarity of the content of the opinion in question. If that opinion, in and of itself, dispels all reasonable scientific doubt with sufficient clarity, the authority does not have to provide any further clarification.

69.

If, on the other hand, the opinion does not in itself dispel such doubts with the necessary clarity, the authority may approve the development only after providing additional details to remove the remaining doubts.

70.

The tenth question concerns the situation where the competent authority does not endorse the findings of one of its inspectors.

71.

Here, too, the test for the need for additional details is the removal of reasonable scientific doubt. Where the inspector’s findings prompt such doubt, the development may be approved only if the authority provides further data to dispel that doubt.

72.

Contrary to what has been argued by An Bord Pleanála and Ireland, the relationship between the inspector and the authority is of no relevance in this regard. The decisive factor is, rather, whether the inspector’s findings give rise to reasonable scientific doubt as to the findings on which the authority relies.

73.

Finally, the eleventh question seeks to generalise the previous conclusions with respect to the obligation to state reasons. It seeks to clarify whether the authority must provide detailed and express reasons for all elements of its decision.

74.

Here, too, it is the case that the competent authority must, certainly for those elements of its decision which are capable of giving rise to reasonable scientific doubt, state detailed and express reasons that are such as to dispel that doubt.

75.

In so far as An Bord Pleanála submits in particular that its decision is based not only on the Natura impact statement but also on various other information sources, it should be noted that the statement of reasons for that decision must make it clear on which of those information sources it is founded. Furthermore, in so far as those information sources are contradictory, the statement of reasons must remove any such contradictions to the extent necessary to dispel all reasonable scientific doubt as to the decision.

76.

The answer to the ninth, tenth and eleventh questions must therefore be that the competent authority must provide, for those elements of a decision to approve a development under Article 6(3) of the Habitats Directive which are liable to give rise to reasonable scientific doubt about whether the effects of that development are non-detrimental to the integrity of the site concerned, detailed and express reasons that are such as to dispel that doubt. This is true in particular of doubt prompted by the findings of an inspector. Although the authority may refer by way of reasons to a scientific expert opinion, that also must be capable of excluding all reasonable scientific doubt.

77.

So far as concerns the questions concerning the EIA Directive, it is necessary, first of all, to determine which version of that directive is applicable ratione temporis. Although the request for a preliminary ruling refers on a number of occasions to the directive as amended, the most recent amendments, introduced by Directive 2014/52/EU, ( 26 ) apply, pursuant to Article 3 thereof, only to projects in respect of which certain procedural steps were initiated after 16 May 2017. The case in the main proceedings, however, concerns a consent granted on 11 July 2014 to which — as, indeed, the national court and the parties to the proceedings recognise — the provisions of the previous version of the EIA Directive are still applicable.

78.

Against that background, I shall begin by answering the question concerning information on the effects on certain species, before addressing the questions concerning the assessment of alternatives.

79.

The fourth question concerns the consideration of environmental effects in the environmental impact assessment. It seeks to clarify whether an environmental impact statement must expressly address what significant effects the proposed project will have on the species identified in that statement.

80.

An Bord Pleanála expresses doubts as to the relevance of this question to the national proceedings, claiming that it is not an admissible cause of action in those proceedings. The counter-argument, however, is that, in accordance with settled case-law, ( 27 ) questions referred for a preliminary ruling by a national court in the factual and legislative context which that court is responsible for defining, and the accuracy of which is not a matter for the Court to determine, enjoy a presumption of relevance. The Court may decline to rule on a question referred for a preliminary ruling by a national court only where it is quite obvious that the interpretation of EU law that is sought bears no relation to the actual facts of the main action or its purpose, where the problem is hypothetical, or where the Court does not have before it the factual or legal material necessary to give a useful answer to the questions submitted to it. On those criteria, the fourth question is admissible.

81.

The environmental impact statement referred to in this question is a concept of Irish law, the interpretation of which does not fall to the Court of Justice. According to the information provided by An Bord Pleanála in relation to Section 50(2) of the Roads Act, however, that statement incorporates, in essence, the information which a developer must provide in connection with his application for consent under Article 5(3) of the EIA Directive.

82.

I therefore construe that question as asking whether the information referred to in it must be provided by the developer in accordance with Article 5(3) of the EIA Directive. Pursuant to subparagraph (c) of that provision, the information to be provided by the developer includes, inter alia, at least the data required to identify and assess the main effects which the project is likely to have on the environment.

83.

Article 5(1) of, and Annex IV(3) to, the EIA Directive make it clear which environmental media must be examined. According to those provisions, the developer must provide a description of the aspects of the environment likely to be significantly affected by the project, including, in particular, fauna and flora. This is consistent with the objective assigned to the environmental impact assessment in Article 3(a) of identifying, describing and assessing the direct and indirect effects of the project on fauna and flora.

84.

Since the fauna and flora are made up of the various species present [on the site concerned], the developer must provide information on the effects on certain species. However, that obligation does not cover all effects on all species present, but only the main effects. That restriction to the main effects is confirmed, moreover, by the fact that, under Article 5(1) of the EIA Directive, the developer is required to provide only information which is relevant and which he can reasonably be required to compile.

85.

The concept of main effects should be interpreted in the light of Articles 1(1) and 2(1) of the EIA Directive, according to which projects that are likely to have significant effects on the environment must be subject to an assessment of their effects. Effects which are not likely to be significant, on the other hand, are not main effects within the meaning of Article 5(3) of the EIA Directive.

86.

As to which effects are to be considered significant, a number of factors may be relevant. The key points of reference, however, are to be drawn from the legal protection of the elements of the environment concerned.

87.

Thus, potential effects on species which are protected by the Habitats Directive (or by national law), for example, are, as a rule, to be regarded as significant ( 28 ) and must therefore also be included in the information provided by the developer, even if only individual specimens are affected in the case in question.

88.

Effects sustained only by individual specimens of far more widely distributed specimens that are not subject to any special protection, on the other hand, are not normally main effects about which the developer must provide information.

89.

The particular circumstances of the individual case may support different conclusions with respect to what may be the main effects. Thus, the degradation of an individual specimen of a widely distributed species might be significant, if it is an exceptional specimen, such as a particularly old tree, for example.

90.

For the purposes of a judicial challenge to a development consent on the basis of an infringement of Article 5(3) of the EIA Directive, this means that an applicant must show which potential significant effects of the project concerned the developer has not adequately assessed and discussed. The fact that certain species are mentioned but are not subject to further assessment is not in itself sufficient to discharge that onus. Depending on the species involved, however, it may be relatively easy to demonstrate why the potential effects may be significant.

91.

In short, the answer to the fourth question must be that, in accordance with Article 5(3)(c) of the EIA Directive, the developer must provide the information necessary to identify and assess potential significant effects which the project may have on flora and fauna. The information required includes in particular the effects on protected species as well as on species whose presence is affected and is particularly important for other reasons.

92.

The fifth, sixth and seventh questions concern information provided by the developer on alternatives to the project under assessment. In the case in the main proceedings, consideration was given at an early stage to whether the bypass road could ‘span’ the floodplain by means of a bridge. This alternative development was rejected on cost grounds, however. The High Court’s questions seek to ascertain whether the developer must nonetheless provide information on the environmental effects of executing the road development project in that way.

93.

The fifth question seeks to ascertain whether an alternative is to be regarded as one of the ‘main alternatives’ within the meaning of Article 5(3)(d) of the EIA Directive even in a case where the developer rejected it at an early stage.

94.

For the purposes of assessing which alternatives are to be regarded as main alternatives, the relevance of those alternatives to the environmental effects of the project or to their avoidance should be decisive. The purpose of the EIA Directive, after all, according to Article 3 thereof, is to identify, describe and assess the environmental effects of projects. Alternatives therefore are of interest first and foremost if they are capable of influencing the environmental effects of the project concerned.

95.

Although the stage at which another solution was rejected is irrelevant from that point of view, it may indirectly have a bearing on the extent of the reasons to be given. The extent of those reasons forms the subject matter of the sixth and seventh questions.

96.

For the purposes of Article 5(3) of the EIA Directive, therefore, alternatives are main alternatives if they are capable of having a significant impact on the environmental effects of the project concerned.

97.

Although the request for a preliminary ruling does not refer a question in this regard, it is important, before answering the sixth and seventh questions, to address the fact that Article 5(3)(d) of the EIA Directive requires only information on the other alternatives studied by the developer. Indeed, the national court proceeds on the assumption that the developer ‘studied’ the aforementioned bypass road development option. That notwithstanding, the fundamental decision on the part of the EU legislature to place reliance on the assessment by the developer also has a bearing on the information which a developer provides on the alternatives he has studied.

98.

In the light of the EU’s environmental policy objective of ensuring a high level of environmental protection, laid down in Article 191(2) TFEU and Article 37 of the Charter of the European Union, as well as the precautionary principle and the principle of preventive action, also enshrined in Article 191(2) TFEU, it seems desirable that the alternatives to a project should be examined as comprehensively as possible. Such an approach would make it possible to select the project option which restricts the adverse environmental effects of that project to a minimum.

99.

It is in line with this thinking that the strategic environmental assessment report preparation of which is required by Article 5(1) of the Directive on the assessment of the effects of certain plans and programmes on the environment ( 29 ) includes reasonable alternatives.

100.

In Article 5(3)(d) of the EIA Directive, however, the EU legislature chose a different approach. Under that provision, the information to be provided by the developer is to include at least an outline of the main alternatives studied by him and an indication of the main reasons for his choice, taking into account the environmental effects. Annex IV(2) to the directive repeats this.

101.

As the national court requesting a preliminary ruling, An Bord Pleanála and Ireland submit, the aforementioned legislative choice is also readily apparent from the drafting history of Directive 97/11/EC. ( 30 ) Both the Commission ( 31 ) and the Parliament ( 32 ) proposed an obligation requiring the developer to provide a description of the main alternatives that might be envisaged. Their proposals did not prevail, however.

102.

Furthermore, as early as 1980, the Commission had proposed that a description be provided of the alternatives that seemed to be reasonably feasible ( 33 ) and, even then, the Council restricted that obligation to the text that also appears in the EIA Directive that is now applicable. ( 34 )

103.

And the most recent, not yet applicable, amendments introduced by Directive 2014/52 have, notwithstanding more extensive proposals from the Commission ( 35 ) and the Parliament, ( 36 ) adhered to the requirement in Article 5(1)(d) that only the reasonable alternatives studied by the developer be described.

104.

The drafting history relating to Article 5(3)(d) of the EIA Directive thus confirms the conclusion to be drawn from its wording that the developer must provide information only on the alternatives which he has studied, but not on alternatives which might be feasible but which he did not consider.

105.

More extensive obligations in respect of the examination of alternatives, which are independent of the substantive requirements applicable to the project in question, are laid down in the Espoo Convention, referred to in the request for a preliminary ruling. ( 37 ) In accordance with Article 4(1) of, and Annex II(b), (c) and (d) to, that Convention, a description of reasonable alternatives and their effects on the environment must be provided.

106.

That Convention does not, however, pursuant to Article 2(2) thereof, provide for an environmental impact assessment for all projects which are subject to the EIA Directive, but only for certain projects that are likely to cause significant adverse transboundary impact.

107.

It is true that, for the purposes of a uniform interpretation, it would be desirable to interpret the EIA Directive in accordance with that Convention, ( 38 ) since much of the Directive is intended to implement the Convention. ( 39 ) Furthermore, the EU’s powers must be exercised with due regard for international law; consequently, EU secondary law must in principle be interpreted in accordance with the EU’s obligations under international law. ( 40 )

108.

However, in the light of its wording and legislative history, it is not possible to interpret Article 5(3)(d) of the EIA Directive as meaning that a project may obtain development consent only if the reasonable alternatives to it are also described and their effects on the environment are also assessed.

109.

The question as to whether the rules on the assessment of alternatives which are applicable to certain projects under the Espoo Convention are by extension directly applicable to the EIA Directive, because, regard being had to its wording and to the purpose and nature of that Convention, the latter contains a clear and precise obligation which is not subject, in its implementation or effects, to the adoption of any subsequent measure, ( 41 ) has not been raised. Nor, presumably, would it be ultimately relevant to the judgment to be given in the main proceedings, since the project at issue does not, prima facie, fall within the scope of that Convention. There is therefore no need for the Court to give a ruling.

110.

At first sight, it seems unsatisfactory that the examination of alternatives in the environmental impact assessment should be crucially dependent on the developer. However, that rule is — to some extent at least — sufficient for the purposes of the primarily procedural nature of the EIA Directive.

111.

Thus, whether and to what extent the decision on a project must make reference to the reasons for the choice made in such a way as to take into account the environmental effects is not clarified in the EIA Directive. That directive does not lay down any substantive requirements in respect of granting development consent to a project. ( 42 )

112.

Even the fundamental or essential obligation laid down in Article 3 of the EIA Directive not only to identify and describe the direct and indirect effects of a project on certain factors but also to assess them in an appropriate manner in the light of each individual case, ( 43 ) as relied on by Mr Holohan and the other applicants in the main proceedings, does not in itself impose any substantive requirements in respect of the project concerned.

113.

The developer may accordingly have an obligation under other provisions not only to take account of alternatives, but then also to document them.

114.

Thus, an approval under Article 6(4) of the Habitats Directive would presuppose the absence of any alternatives. Such approval might conceivably be the case in the main proceedings were it to prove impossible to dispel all reasonable scientific doubt about whether the project is non-detrimental to the integrity of the protected areas concerned.

115.

Moreover, the protection of species might also make an assessment of alternatives necessary in the present case. It follows from the order for reference that — presumably because of the presence of bats — there is some debate as to the need for exceptions to the system of strict protection laid down in Article 12 of the Habitats Directive. ( 44 ) Such exceptions are permissible under Article 16 only where there is no satisfactory alternative.

116.

It may also occur that the authority competent to grant consent requires the developer to provide it with alternatives, as provided for in recital 13 of the EIA Directive. This is likely to be necessary in particular where the authority has to make a discretionary decision on the approval of the project.

117.

Finally, the United Kingdom rightly submits that the assessment of alternatives in the context of the strategic environmental assessment of plans and programmes goes at least some way towards offsetting the lack of a compulsory examination of alternatives as part of the environmental impact assessment.

118.

The sixth and seventh questions seek to clarify what information the developer must provide on the environmental effects of the alternatives. Whether such information must be included at all is the subject matter of the seventh question, while the sixth question is plainly concerned with the extent to which it should be included, if it has to be.

119.

In accordance with Article 5(3)(d) of the EIA Directive, the information to be provided by the developer must include at least an indication of the essential reasons for his choice, taking into account the environmental effects.

120.

This provision gives further expression to the fact that the scheme of Article 5(3)(d) of the EIA Directive is that the assessment of alternatives should be carried out by the developer. The latter is not obliged, at least by that directive, to make his choice according to the environmental effects of the various alternatives, or to take the environmental effects into account at all in his decision. Rather, he is obliged only to make known the reasons for his choice in so far as these relate to the environmental effects.

121.

If, however, as is apparently the case in the main proceedings, the choice made was determined not by the environmental effects but by purely financial considerations, it follows that there are no reasons for the choice that have to be made known.

122.

In particular, Article 5(3)(d) of the EIA Directive imposes no obligation to identify, describe and assess the environmental effects of the alternatives.

123.

The position would be different, however, if substantive rules laid down in other provisions required the developer to take account of alternatives. ( 45 ) In that event, the developer would generally have to record these also in accordance with Article 5(3)(d) of the EIA Directive and indicate the reasons justifying his choice of the alternative selected, in so far as those reasons relate to the environmental effects, in the context of those other provisions.

124.

In accordance with Article 5(3)(d) of the EIA Directive, the developer must therefore indicate the reasons which determined the choice he made from various options available to him, in so far as those reasons relate to the environmental effects of the project and of the alternatives.

125.

I therefore propose that the Court’s answer to the request for a preliminary ruling should be as follows: