In keeping with this edition’s coastal theme, this article explores an ecosystem found along the coast of South East Queensland (SEQ). With its distinctive lowgrowing plants, salty muddy ground, and its proximity to mangroves, saltmarsh is generally easy to recognise. Sadly, it has also been an undervalued ecosystem, and as a result has borne the brunt of mismanagement and outright attempts to drain and fill it in over the years.
Thankfully, coastal saltmarsh is a reasonably resilient ecosystem due to its saline nature. Not too many weeds can survive the salt, and the boggy nature of the ground combined with hungry mosquitoes and sandflies can deter most visitors and machinery. However, when it dries out, saltmarsh can be a favoured place for illegal dumping and hooning.
In SEQ, good tracts of coastal saltmarsh can be found from the Noosa River in the north through to the southern Gold Coast areas. Some larger tracts of saltmarsh include Eprapah Creek, Hays Inlet, Pumicestone Passage, Caboolture River mouth, Logan River mouth, and the southern parts of North Stradbroke Island.
I recently had the muddy pleasure of counting shorebirds at the Geoff Skinner Reserve – Brisbane’s largest tract of saltmarsh. Despite being weighed down by my snowshoe-sized boots caked with mud, it was a peaceful and expansive place to explore. Afterwards, I wanted to champion this ecosystem and celebrate the fact that it is one of only a handful of ecosystems in SEQ recognised as nationally significant. It is listed as Vulnerable under Commonwealth environment legislation.
Coastal saltmarsh often adjoins mangroves; but unlike mangroves that are inundated daily by tides, saltmarshes are inundated less regularly by king tides and storm surges. Saltmarsh soils consist of waterlogged silts and clays with high organic content. Just below the surface are iron sulphides, which when disturbed, can release sulphuric acid – a distinctive smell that accompanies you when walking through saltmarsh muds. The plants and sediments within saltmarsh store large quantities of carbon making saltmarsh ecosystems important players in the carbon sequestration race.
In SEQ, coastal saltmarsh is defined as regional Ecosystem 12.1.2. There are less than twenty Land for Wildlife properties in SEQ containing this ecosystem – the lucky few who can say that they have a nationally significant coastal ecosystem in their backyard. They occur from Beerburrum, to Deception Bay, Toorbul, Hays Inlet, out to the islands of Macleay and Karagarra and south to the Jacob’s Well Environmental Education Centre.
Marine Couch (Sporobolus virginicus), Beaded Samphire (Sarcocornia quinqueflora) and Seablite (Suaeda australis) are common native groundcovers found in coastal saltmarsh.
The most obvious wildlife inhabitants of coastal saltmarsh are crabs, snails and periwinkles, plus prawns and fish when inundated. Insects are also abundant, including those annoying midges. Many birds and bats feed, roost or take refuge in coastal saltmarshes, including migratory shorebirds discussed on pages 10-11.
These days it is well recognised that coastal ecosystems such as mangroves and saltmarshes are essential for fisheries, coastal erosion protection and nutrient filtering. They are also beautiful, almost other worldly places where you can stretch your legs and imagination. If you would like to get involved in protecting and monitoring tidal ecosystems, Mangrove Watch, may be for you. For details, visit www.mangrovewatch.com.au
Articles by Deborah Metters
Land for Wildlife Regional Coordinator
Healthy Land and Water