The Adelaide and Mount Lofty Ranges (AMLR) region contains a diversity of wetland ecosystems. These ecosystems are critical to improving water quality, regulating water availability and the conservation of biodiversity.
What are wetlands?
Wetlands are areas that are seasonally or permanently waterlogged or inundated. This includes natural wetlands and those that are constructed to improve water quality.
Why wetlands are important
Wetland ecosystems are important because of the services they provide such as:
- improving water quality through the capture, retention and breakdown of excess nutrients, sediments and pollutants
- improving seasonal water availability and reducing erosion through the capture and slow release of water
- carbon storage within the soil and living plants
- providing critical habitat for native species (many of which are threatened and restricted to such ecosystems)
- supporting recreational activities, tourism and cultural heritage.
Wetlands of the AMLR
Within the region, there are five main types of wetlands:
- Seasonal wetlands of the Adelaide Plains
These wetlands historically filled during winter and dried out in summer to mud flats with fringing plants. During winter, the open water would have provided habitat for waterbirds (such as ducks, swans, rails, grebes and snipes) and the summer mud flats would have provided foraging habitat for a range of other birds (such as waders). The majority of these wetlands have been developed and changes to the hydrology of those that remain has reduced their health, diversity and associated ecosystem services.
- Permanent wetlands (including swamps)
These wetlands are prominent features of the landscapes of the Adelaide Hills and Fleurieu Peninsula, where the rainfall is higher than on the plains. During winter, some may have standing water but they are more often typified by waterlogged soils throughout the year. Their source of water includes surface water flow, subsurface water flow (through the soil above the watertable) and sometimes from the watertable itself. The diversity of plant and animal species here is high, with many species reliant on these ecosystems, including endemic and threatened species.
The majority of permanent wetlands are found in landscapes developed for production. They are often isolated from other native ecosystems and are subject to changes in ecological and hydrological processes, as well as threats from pest plants and animals and pollution. The future preservation of these remaining wetlands is reliant upon the management decisions of individual landholders.
A subset of these wetlands has been listed as a threatened ecological community under the national Environment Protection and Biodiversity Conservation Act 1999. These “swamps of the Fleurieu Peninsula” are listed as critically endangered, which is the highest extinction risk category.
Fleurieu swamps are significant due to the large number of native plant species recorded in them (well over 300), almost a third of which are considered threatened at the regional scale. They also provide food and habitat for threatened animals, including the Southern Pygmy Perch, Bibron’s Toadlet, Yellow-bellied Water Skink and Mt Lofty Ranges Southern Emu Wren.
Watch this short video on one farmer’s work to protect the swamps on his Fleurieu property. Kris Andrew manages an 850 ha property at Hindmarsh Valley on the Fleurieu Peninsula. Hear how Kris plans to manage 3500 breeding sheep, increase the lambing percentage and how he has a plan in place to protect 100 hectares of the threatened Fleurieu Peninsula swamps.
- Permanent pools in watercourses
Permanent pools of open water are often found in the channels of watercourses. These pools become isolated during the dry summer months and reconnect during periods of high flows. They provide critical refuges for fish and other aquatic life during dry periods. These species are particularly vulnerable to change over the summer months, such as declining water quality or the drying of pools. This can lead to local extinction of fish and other aquatic life. The majority of watercourses and pools in this region have been modified by the development of the landscape and associated changes in ecological and hydrological processes.
The region contains a large number of estuaries, including typical tidal and riverine estuaries, as well as a range of creeks and streams with intermittent outlet to marine waters.
- Constructed wetlands
Constructed wetlands can improve water quality, manage flooding and store water for subsequent harvesting. Such wetlands are an efficient means of trapping sediment, nutrients and other pollutants and can also provide value as habitat for birds and social amenities for people.
An eight-year Mosquito Monitoring Program found that constructed wetlands are generally water bodies of high quality unlikely to cause mosquito problems. The eight wetlands monitored showed a natural mosquito presence however, healthy populations of predatory aquatic invertebrates (e.g. dragon flies, beetles) and vertebrates (fish) kept these numbers low.
Changes to the wetlands of the AMLR
An estimated 30% of the region’s wetlands remain, with most having been modified or degraded. Only eight per cent are formally protected.
What’s the region doing to conserve wetlands?
There are five main strategies required to conserve wetlands:
- protect those that are intact (in terms of species and ecological/hydrological processes)
- remove existing threats
- reinstate ecological and hydrological processes to facilitate repair
- reconstruct and reconnect wetlands where this will result in broader outcomes for biodiversity, water quality, flood mitigation and water use
- address emerging threats such as climate change or new pest incursions.
The Natural Resources AMLR is delivering and supporting programs to implement these strategies.
What can you do to conserve wetlands and what support is available?
The majority of the wetlands within the AMLR region are found outside of formal parks and reserves. So the management decisions and actions of individuals are critical to their conservation.
If you own land, the most important things you can do are to retain any existing wetlands, remove threats and reverse past impacts. Technical support and funding is available for such activities.
If you do not own land, there are many opportunities to participate in volunteer activities to protect and manage biodiversity.