On 21 July 2016, the Court of Justice of the European Union (CJEU) handed down an important preliminary ruling in the Orleans case, which concerns the expansion of the Antwerp port through the construction of a new dock, the Saeftinghe dock. The planned expansion raises a number of nature conservation issues.

The background to the case can be summarised as follows.

In April 2013, the Flemish government adopted a regional development plan (gewestelijk ruimtelijk uitvoeringsplan) for the left bank of the Antwerp port (hereinafter "'the RDP").

Developing the proposed Saeftinghe dock will lead to the partial disappearance of a Natura 2000 site, in particular 20 hectares of tidal mudflats and marshes.

Natura 2000 sites are valuable ecological sites which are protected under the European Habitats and Birds Directives. If a plan or project is likely to have a "significant effect" on a protected habitat and/or species of a Natura 2000 site, the Member State in question is obliged to conduct an "appropriate assessment" of the implications of the plan or project, pursuant to Article 6(3) of the Habitats Directive. The national authorities may only agree to the plan or project after having ascertained that it will not adversely affect the integrity of the site concerned.

If the plan or project will adversely affect the integrity of a Natura 2000 site, it can only proceed if the three requirements set out in Article 6(4) of the Habitats Directive are fulfilled: (i) there are no alternative solutions, (ii) there are imperative reasons of overriding public interest to go ahead with the plan or project, and (iii) the Member State adopts compensatory measures to ensure the overall coherence of Natura 2000. The Member State must also inform the European Commission of the compensatory measures adopted.

Developers and national authorities sometimes try to circumvent the burdensome derogation procedure provided for by Article 6(4) of the Habitats Directive. One oft-used technique is the development of a new natural site. By qualifying the development as a "mitigating measure" and including it in the appropriate assessment required by Article 6(3) of the Habitats Directive, they hope to avoid application of the Article 6(4) procedure.

The case law indicates, however, that both the Belgian Council of State and the Court of Justice of the European Union tend to interpret Article 6 of the Habitats Directive narrowly. The Council of State, for instance, has ruled that a nature creation programme cannot be characterised as a "mitigating measure" to be taken into consideration when performing the appropriate assessment required by Article 6(3) of the Habitats Directive. Rather such a programme should be considered a "compensatory measure", meaning the requirements of Article 6(4) of the Habitats Directive must be met (Council of State, 29 November 2011, no. 216.548, and 29 March 2013, no. 223.083).

The Flemish Region and the Port of Antwerp raised a similar argument in the present case.

After partial suspension of the original RDP by the Council of State (decision no. 225.676 of 3 December 2013), the Flemish Region partially modified the plan.

The modified RDP establishes a phased approach. Before the Saeftinghe dock can be developed, new ecological core areas must be created, and a building permit for the new dock can only be issued following a decision by the Flemish government establishing the existence of these core areas. According to the Flemish government and the Port of Antwerp, owing to this approach, the project will have no significant adverse effects on the natural environment. These measures are described as "conservation measures" within the meaning of Article 6(1) of the Habitats Directive, probably in order to avoid the classic discussion on mitigating versus compensatory measures.

This approach, however, did not satisfy the applicants, which commenced new proceedings to suspend and set aside the modified RDP. While the Council of State did not suspend the modified plan, it did request a preliminary ruling from the Court of Justice. In essence, the Council of State asked whether the measures to create new ecological core areas may be taken into account in the "appropriate assessment" required by Article 6(3) of the Habitats Directive or whether they should be considered "compensatory measures" to which Article 6(4) applies.

Before the Court of Justice, the Flemish government argued that these new core areas should be taken into account in the "appropriate assessment". According to the Flemish government, the present case differs from the Briels case to which the applicants referred (Court of Justice 15 May 2014, C-521/12, Briels et al.). In Briels, the new natural habitat would have been developed only after the existing natural habitat was affected. In the present case, by contrast, development will be possible only after the permanent establishment of habitats and species habitats in the ecological core areas. The government argued that the newly established core areas would already contribute to the integrity of the Natura 2000 site by the time the existing habitats are affected. These "conservation measures" should thus be balanced against the loss of existing habitats when performing the "appropriate assessment" required by Article 6(3) of the Habitats Directive. In sum, the extension of the port will not adversely affect the conservation objectives of the habitats concerned, and there is no need to apply the procedure set out in Article 6(4).

The Court of Justice did not follow this reasoning and confirmed its narrow interpretation of Article 6 of the Habitats Directive. The Court admitted that the circumstances are not identical to those of the Briels case. They are, however, "similar insofar as they involve, at the time of assessing the implications of the plan or project for the site concerned, the identical premise that future benefits will mitigate the significant adverse effects on that site, even though the development measures in question have not been completed" (para. 56). The Court referred to the precautionary principle and noted that the positive effects of the future creation of a new habitat are difficult to forecast. The Court concluded that the measures do not qualify as "conservation measures" within the meaning of Article 6(1) of the Habitats Directive and must therefore be considered "compensatory measures" under Article 6(4).

The Court of Justice's interpretation of Article 6 of the Habitats Directive is binding on the national courts. It is therefore highly likely that the Council of State will set aside the RDP, since the measures in question are in fact compensatory measures and the Flemish Region failed to apply the procedure laid down in Article 6(4) of the Habitats Directive.

Developers and national authorities should duly note that, when it comes to environmental protection, confusing conservation measures with compensatory measures may adversely affect their plans.