In the context of a project, impact compensation should apply to all the components of biodiversity, such as species diversity, protected habitats, and ecosystem services.
This last phase of the sequence involves:
- A wide variety of methods to assess the equivalence between NNL and NG (see Section 3.4.1 – Equivalence assessment methods).
- Methods that are both general in their assessment of all the components of biodiversity, and specialise in a specific aspect of biodiversity, for example wetlands.
- Variable regulatory requirements in terms of ecological equivalence from one country to another, where like-for-like or other forms of equivalence are applied.
In addition, several implementation options exist, depending on the type of compensation applied, either on demand or with offset banking (see Section 3.4 – Compensation):
- Direct (compensation on demand): compensation by request of the project developer who implements compensation by themselves through for example purchase of land and/or agreements.
- Offset operator (compensation on demand): management of compensation measure by a third- party organisation that implements and manages it on behalf of the project owner.
- Purchase of compensation units (offset banking): financial acquisition of compensatory measures already undertaken.
Because of the variability of techniques used, several types of intervention co-exist in the field of compensation and make it difficult to assess the effectiveness of interventions. To maximize ecological value, interventions should be undertaken over large areas because the larger the compensation site, the greater the chance of achieving strong ecological gains, in respect of the different key principles (see Section 3.4 – Compensation). This leads to the principle of pooling different compensation measures on a single or a limited number of sites or, going a step further, to embed compensation strategies in strategic planning (see Section 3.4.2 – Effective Compensation implementation). However, methods of securing land for compensation sites also pose a major problem for infrastructure project owners. Acquisition is sometimes costly and may be impossible on private land, and ensuring compensation occurs through land agreements and leases is sometimes too precarious.