Ecology, disturbance and restoration of coastal saltmarsh in Australia: a review

Abstract

It is clear that saltmarshes are a unique and important component of the coastal biosphere of Australia. Their contribution ranges from stabilisation of fine sediments and providing an excellent protective buffer between land and sea, to their diverse blend of terrestrial and marine fauna. Further, saltmarsh plants are highly specialised and adapted to fill a harsh niche allowing them to act in roles that other vegetation types cannot. Saltmarsh habitats are recognised for their importance to migratory waders under the Ramsar convention, but it is becoming increasingly evident that they are also important to a variety of commercially valuable fish and native mammal species. Activities that are detrimental to saltmarshes continue and need to be addressed in order to conserve remaining saltmarsh areas. In general, urbanisation of the catchment has lead to filling of saltmarshes, tidal restriction, use by recreational vehicles, grazing, trampling and increased sedimentation and nutrient runnoff allowing colonisation and invasion of mangroves. These disturbances have a number of ecological consequences ranging from weed infestation to complete changes in the species composition and ecology. Reversing the disturbance is not always simple and can require extensive groundwork to be successful. Rehabilitation of existing saltmarsh areas has been a successful means to enhance this habitat. In general, it requires relatively little effort to remove weeds and fence off areas to regenerate naturally. Saltmarsh areas have been shown to respond well to this type of manipulation. Restoration and creation require substantial effort and planning to ensure a successful outcome. However, given the right environmental combinations of elevation, tide and salinity, saltmarsh will establish and grow. To speed the process transplantation of saltmarsh plants can be considered either from donor sites or plants propagated in green houses.

Modelling ecological change over half a century in a subtropical estuary: impacts of climate change, land-use, urbanization and freshwater extraction

“…No equivalent data were available to initialise biomass distributions of microphytobenthos and macroalgae in the model, so they were respectively set at nominal concentrations of 1.0 mg N m −3 and 100 mg N m −3 , then allowed to evolve in response to conditions. Zones of riparian vegetation, including rushes, salt marshes and mangroves, are also common through out much of the Clarence River Estuary system, where they support communities typically dominated by detri tivores (Laegdsgaard 2006). It is not clear how effective these zones are in removing dissolved nutrients, with mature systems potentially becoming nutrient sources (e.g.…”

“…The evidence for removal of particulate material is more compelling but still difficult to quantify across a diverse estuarine system (e.g. Laegdsgaard 2006). Riparian zones have therefore been represented implicitly as a decay term for detritus.…”

“…Denitrification rates within mangrove forests tend to be much lower than those for saltmarshes (Rivera-Monroy & Twilley 1996, Valiela & Cole 2002 and limited measurements within Australian mangroves have shown them to be net tidal exporters of nitrogen (Boto & Robertson 1990). Saltmarshes in Australia tend to be less productive than those in other parts of the world, with less frequent tidal inundation (Saintilan & Williams 1999), and are typically well-oxygenated with limited denitrification (Laegdsgaard 2006). It has therefore been suggested that there is little net exchange of nitrogen between Australian saltmarshes and adjacent waterways, although they may significantly moderate catchment inputs as observed in other regions (Valiela & Cole 2002).…”

Coastal wetlands of temperate eastern Australia: will Cinderella ever go to the ball?

“…Even so, very many other coastal systems along the temperate Australian seaboard that are extremely important from ecological, economic and social perspectives remain very poorly known: examples include estuarine wetlands associated with the many large drowned river valleys of coastal New South Wales, including the Clarence, Manning and Hawkesbury Rivers, and the Gippsland Lakes and Corner Inlet-Nooramunga complexes in Victoria. Several syntheses of the ecology of coastal saltmarshes in Queensland, New South Wales and Victoria (Laegdsgaard 2006;Saintilan 2009;Boon et al 2011) are now available, as well as a recent review of the ecology of temperate mangroves (Morrisey et al 2010) to match the very large literature on tropical mangroves (e.g. Alongi 2009).…”

A Methodology to Map Ecosystem Functions to Support Ecosystem Services Assessments

“…Mangroves, Samphire and Salt Marshes EPA (Young and Dillewaard 1999) Mangroves are habitat to number of fauna (Tomlinson 1994). Saltmarsh habitats are recognised for their importance to migratory waders under the Ramsar convention, but it is increasingly evident that they are also important to a variety of commercially valuable fish and native mammal species (Laegdsgaard 2006 Plants provide habitat for fauna (Morrison et al 2006). Reefs EPA (2006b) Reef and rocky reef habitats have very high biological importance, and are habitat to numerous fauna (Roberts et al 2002).…”