In the UK, the European Habitats Directive (Directive 92/43/EEC) requires local (or competent) authorities to assess the impact of local plans on the Natura 2000 network of protected sites. The Directive is given domestic effect by the Conservation of Habitats and Species Regulations (the Habitats Regulations) which requires the assessment of effects on European sites (comprising Special Protection Areas (SPAs), Special Areas of Conservation (SACs) and Ramsar sites). In England, this requirement is implemented via a Habitats Regulations Assessment (HRA) which comprises a series of mandatory tests.
The stages of HRA are:
Stage 1 – Screening: To test whether a plan or project either alone or in combination with other plans and projects is likely to have a significant effect on an international site;
Stage 2 – Appropriate Assessment: To determine whether, in view of an international site’s conservation objectives, the plan (either alone or in combination with other projects and plans) would have an adverse effect (or risk of this) on the integrity of the site with respect to the site structure, function and conservation objectives. If adverse impacts are anticipated , potential mitigation measures to alleviate impacts should be proposed and assessed;
Stage 3 – Assessment of alternative solutions: Where a plan is assessed as having an adverse impact (or risk of this) on the integrity of an international site, there should be an examination of alternatives (e.g. alternative locations and designs of development); and
Stage 4 – Assessment where no alternative solutions remain and where adverse impacts remain: In exceptional circumstance (e.g. where there are imperative reasons of overriding public interest), compensatory measures to be put in place to offset negative impacts.