Guidance on Wind Energy Developments and EU Nature Legislation 27
3. GENERAL APPROACH AND PRINCIPLES DURING
SCREENING AND APPROPRIATE ASSESSMENT
This aim of this chapter is to provide guidance and good practices on some general issues that can arise
during the screening and appropriate assessment procedures, such as assess ing significance of the effects ,
the scoping procedure and setting a baseline. It also covers issues of uncertainty, cumulative effects and
3.1 Significance of the likely effects
Article 6(3) of the Habitats Directive refers to the need to assess the likelihood of a plan or project having
significant effects on a Natura 2000 site. The screening process assesses whether it is likely to have a
significant effect on the site. If significant effects cannot be excluded with certainty, an appropriate assessment
is necessary. The appropriate assessment assesses the likely effects on the Natura 2 000 site against its
conservation objectives and whether implementing the plan or project may or will adversely affect the integrity
of the site.
One of the major challenges faced when undertaking an assessment of a plan or project is how to understand
and determine when an effect is significant or not.
It is necessary first to explore the type and extent of effects (‘significant eff ect’), and then to explore the causes
likely to create such effects (‘likely to have … either individuall y or in combination’). Determining whether a
plan or project is likely to have a significant effect will have practical and legal consequences. Therefore, when
a plan or project is proposed, it is important firstly that this key issue is consid ered, and secondly that the
consideration can stand up to scientific and expert scrutiny. The safeguards set out in Article 6(3) are triggered
not by a certainty but by a likelihood of significant eff ects. Mitigation measures cannot be taken into accoun t
at this stage. Transboundary effects are also to be considered (European Comm ission, 2019).
Significance will vary depending on factors such as magnitude of effects, type, extent, duration, intensity,
timing, probability, cumulative effects and the vulnerability of the habitats and spec ies concerned.
Effects typically considered when assessing significance include the f ollowing:
• Direct loss of habitat: a reduction of habitat coverage as a result of physical destruction (i.e. due to its
removal or the placement of construction materials or s ediments); loss of breeding, foraging, resting areas
• Habitat degradation: a deterioration or reduction of habitat quality, e.g. as a result of reduced abundance
of the characteristic species or altered community structure (species compos ition); deterioration of
breeding, foraging, resting areas for species.
• Habitat fragmentation: an alteration of distribution patches of relevant habitats and species, e.g. a
contiguous area of habitat split into two or more small, isolated areas, causing a barrier between habitat
• Disturbance of species: a change in t he environmental conditions (e.g. noise, frequency of people and
vehicles, increase in suspended sediment or dust deposition); e.g. disturbance m ay cause displacement of
species individuals, changes in species behaviour, mortality risk.
• Indirect effects: an indirect change to the quality of the environment (including hydrolog y).
For wind energy developments, typical additional types of effects are the barrier e ffect and the collision risk.
Sources of information to determine the significance of effects may include evidence from similar operations
affecting sites with similar conservation objectives and expert opin ions based on available evidence. However,
the assessment must look at the local circumstances on a site-by-site basis, as what may be significant f or
one site may not be so for another.
The notion of what is ‘significant’ needs to be interpreted objecti vely. The significance of effects should be
determined in relation to the specific features and environm ental conditions of the protected site affected by
the plan or project, taking particular account of the site’s conservation objectives and ecological charact eristics
(European Commission, 2019).