To assess the significance of a particular feature or resource it is essential to know:

• where it is located;
• how wide spread it is;
• how much of it there is; and
• its quality.

Habitat surveys are a basic tool used to assess the value of particular coastal features (such as saltmarsh). They also help to provide:

• the basis for the selection of important conservation areas;
• an assessment of the need for conservation protection;
• a means of record change (in assemblages); and
• a basis of information to assist management decisions.

In the context of monitoring, however, this information is ‘passive’, as it is concerned with the existing location, scale and nature of the resource (as well as the characteristics of any prevailing activities). Taken on its own, it tells us little about change or the potential causes of change. To establish the status of the habitat and whether intervention is required, by way of protection and or management, information is also needed to establish, amongst other things:

• The extent of any loss due to human activity;
• Whether the resource is eroding / accreting;
• Whether the resource is suffering die-back;
• The efficacy of protective legislation; and
• The efficacy of management action.

To achieve this repeat surveys are needed. These may be considered as part of a suite of more ‘active’ approaches to surveillance or monitoring designed to measure change resulting from deliberate actions against a predetermined, desired outcome. Active approaches can be summarised under four headings (relevant definitions are provided in the table below):

• Monitoring to help identify and assess impacts, determine action and give feedback on management effectiveness.
• Surveillance to identify unforeseen change and, where appropriate, ensure compliance with agreed legislative or other control mechanisms.
• Prediction to consider the possible outcome of policy decisions proposed by way of response to an unforeseen incident (e.g. oil pollution) or natural/man induced event (e.g. a storm or sea level rise).
• Assessment of the effectiveness of action (management). This is the final stage and allows us to learn from good and bad practice and feed across to other managers.

The methodologies adopted, for the most part, will be the same. It is the level of detail and frequency that might vary and, importantly, the interpretation that is put upon the information which will convert into knowledge. The knowledge gained is crucial to determining how effective management actions are and, hence, in promoting better decision making. The following table below provides some specific guidance on survey, surveillance and monitoring methodologies for saltmarshes.