Saltmarsh Ecology

In this section we will investigate some of the basic principles of Saltmarsh Ecology. We will review information about the saltmarsh habitat as well as look at some of the inhabitants that scientists study in order to gain an understanding of how saltmarsh habitat works. We will also look at some of the physical conditions and how they affect the productivity and health of saltmarsh habitat. This is important in terms of monitoring saltmarsh habitat. Finally,we will investigate the vegetation and some of the invertebrates which include snails (gastropods) and crabs (crustaceans) and how they interact with the habitat. At the end of this section there  are two short quizzes for you to enjoy and to test your basic understanding of saltmarsh ecology.

Saltmarsh Habitat

Saltmarshes are recognised as ecosystems with high ecological values. They are productive, impressive agents of carbon storage and have a positive impact on water quality entering estuarine waters.   These habitats also play a significant role in estuarine food webs as well as provide habitats and roosting sites for many species of birds including migrating waders. Research has also shown that these habitat areas are utilised by many species of fish and crustaceans including many commercial species.

Saltmarsh systems are dynamic and interact with mangrove forests and terrestrial systems including casuarina and melaleuca forests. Their distribution is based on a number of interacting agents including sea levels, ground water, weather and vegetation. They are complex systems.

Saltmarsh habitats are located in flat areas which receive regular but infrequent tidal flooding. Usually this flooding occurs during king and spring tides. In sub-tropical regions they are generally located on the landward side of mangrove forests. Saltmarsh areas generally have high levels of salinity and low levels of oxygen in their soils due to evaporation, sea water and the lack of agitation by tidal movements. This is an extreme environment where plants are especially adapted to cope. In some areas the conditions are so extreme that there are no plants at all.

Saltmarsh areas are characterised by a mosaic of salt pans, marine couch, samphires and sedges. The maximum height of this vegetation usually ranges between 10 and 30 cm. Saltmarsh areas are often devoid of any shrubs or trees except along the occasional gutter or creek where mangroves can establish themselves.

Saltmarsh Habitat is Under Threat

Despite the ecosystem services saltmarsh habitat provides it is still under threat mainly from human activity. In the past many saltmarsh areas have been "reclaimed" for coastal development including canal estates and industrial activities. Indeed, a number of saltmarsh areas only exist today due to government utilities infrastructure built for community services including power and water treatment. Apart from development activities, other causes of damage include vehicular traffic (both recreational and industrial), stormwater damage, weed infestations which are often caused by local dumping of garden rubbish and even the incursion of mangroves into the saltmarsh habitat.

Of all the coastal ecosystems, saltmarsh is the least studied and understood. It is therefore important that we undertake as much monitoring and assessment of our remaining saltmarsh as possible, so scientists and policy makers can preserve and improve the health of our remaining areas of saltmarsh. This is where assistance from volunteers can make a difference; by providing the data needed to help our scientists understand the dynamics of a productive but endangered part of our coastal ecosystem.   

Apart from vehicle damage weeds and mangrove incursion also provide threats to saltmarsh habitat






Recreational vehicle damage

Damage from stormwater modification and maintenance

Ongoing industrial development


Visitors to Saltmarsh Habitat