According to the criteria of the standard, a hypothetical, forward-looking reference scenario must be built for the assessment of biodiversity and ecosystem services. This scenario depicts the realistic future state of the affected site that can be expected if the project is not implemented. In order not to counteract proactive action by nature conservation actors, we recommend assuming a reference scenario that is permissible and realistic for this site.

The project scenario, on the other hand, describes the future condition of the area if the project is implemented. The difference between the condition in the reference and project scenario is used to estimate ex ante the improvement that will be achieved by the project. The following two figures visualise this.