Natural impact assessment (VNEI)
The biodiversity chapter of the environmental impact assessment
The natural impact assessment is the biodiversity chapter of the environmental impact study (article R.122-5 of the French Environmental Code).
Natural impact assessment (VNEI)
The natural impact assessment is the biodiversity chapter of the environmental impact study (article R.122-5 of the French Environmental Code). It documents the ecological baseline, the project impacts and the Avoid-Reduce-Offset measures. ARKENOR produces a defensible VNEI to secure the authorisation.
Position
The ecological chapter, and the one most often contested.
The natural component, known in France as the VNEI, is the part of the impact assessment dealing with habitats, species and ecological function. It characterises the initial state, assesses impacts, and sets out how they will be avoided, reduced and offset. It is the chapter most frequently attacked in litigation, because it is the one whose conclusions depend most visibly on field evidence.
Its credibility rests on the survey effort behind it: how many campaigns, in which seasons, using which protocols, by whom. A VNEI whose method section is thin invites the question of what the surveys missed.
Method
Characterise the initial state before assessing impact.
Impact cannot be assessed against an unknown baseline. The initial state has to describe what is present, in what abundance and with what conservation stakes, before anything is said about what the project does to it. Files that reverse this order, describing the project first and looking for impacts afterwards, systematically underestimate.
Where the assessment concludes that protected species are affected, it leads directly to a derogation file, and where a European site is in range, to a separate Natura 2000 assessment.
Contestation
The chapter that gets attacked.
Where an authorisation is challenged, the natural component is usually the ground on which it is challenged, for a simple reason: its conclusions rest on field observation, and field observation can be shown to be incomplete. A challenger does not have to prove that a species is present. It is often enough to show that the survey effort could not have detected it.
The defence is documentary and it is built beforehand: dated campaigns, stated protocols, named observers, acknowledged limits. That apparatus is what converts a study into evidence, and it cannot be added retrospectively once the challenge has been filed.
Going further
Related pages.
The natural component connects to these procedures.
- Environmental impact assessment — the containing file
- Four-season surveys — the field evidence
- Protected-species derogation — where the assessment leads
- Natura 2000 incidence assessment — a separate, cumulative obligation
- Avoid-reduce-offset sequence — how impacts are answered
- Offsetting measures — what remains after avoidance and reduction
- Wetland delineation — often decisive for the initial state
- Ecological expertise — the full set of procedures
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