2.1 Why, who and what

Ecosystem services assessment is considered here as a process to consider a management question and reach an objective.

A large variety of tools can be used in order to support this objective, including: stakeholder engagement , scenario building and ecosystem services assessment  and valuation tools.

Before implementing any of these tools, the scope of the assessment has to be defined.

Before undertaking an ecosystem service assessment it is critically important to consider why it is being undertaken, who and what it is being undertaken for, and how best to go about the assessment in the given circumstances.

An initial preparatory step is frequently overlooked with the result being an inefficient use of resources and poorly used marine ecosystem services assessments [Laurans et al., 2013].

Careful considerations should also be given to the resources, knowledge and expertise that will be available for carrying out the assessment. Depending on its aim, the marine ecosystem services assessment may require not only quantitative ecological and economic methods, but also skills in working with stakeholders and delivering communicable outputs.

Finally, to define the aim, scope and expected output of the marine ecosystem service assessment, it may be necessary  to focus on what is meaningful and feasible.

This approach is also useful when scenario building. Scenario building processes are conducted for a clearly established objective.The scenario building process involving stakeholders can be a way to:

• Better understand longer-term issues;
• Better understand the links between ecosystems and human activities;
• Create a “common culture” between stakeholders;
• Develop perspectives together on possible futures (exploratory scenarios);
• Compare these perspectives and choose the best one;
• Develop an action plan (normative scenario) and
• Inform decisions and actions that need to be taken to achieve a desired future.

A scenario building process can take several months but can be longer or shorter depending on the methodologies chosen, resources available and the required level of stakeholder participation. The aims, and consequently the type of scenarios developed, will be different depending on:

• The management question studied
• The governance and environmental contexts of the case study sites
• The legitimacy and skills of the case study team (e.g. implementation of measures)