This section of the manual explores the human and natural factors that may affect saltmarsh habitat and lead to both morphological and ecological change. Determining the nature of change and the causes and processes driving it are fundamental for saltmarsh management (should this be determined to be necessary). Guidance on the selection of suitable management options is then also provided. The issues discussed in the following pages are intended to provide the basis (with the background information provided on saltmarsh morphology and ecology) for assessment of the nature of change or the potential outcome of change.

The first part of this section discusses physical process change and its potential effects on saltmarsh habitat; providing the background for a description of historical change in saltmarsh extent, linked to both natural changes in coastal and estuarine processes and morphological change brought about by human intervention. This historical context and discussion of forcing factors provides a platform from which existing or potential human activity can be assessed. Both past uses that have influenced the development of saltmarshes and current activities that could affect the condition and distribution of saltmarsh are described.

The table below illustrates the key impacts and pressures on saltmarsh habitat and these are then discussed further in this section.

Key impacts and pressures leading to change in saltmarsh habitat (from Doody, 2001)