Martin Bend Wetland: a diverse and abundant ecosystem right on our doorstep
23 January 2023
Located on the outskirts of Berri on the River Murray, Martin Bend wetland is a popular place for locals and tourists to visit. Featuring a 3.4 km walking trail loop, visitors gain a unique perspective of the area with the chance to get an up close view of the diverse local flora and fauna.
What are the different wetland types of Martin Bend?
Martin Bend is in fact a complex of interconnected wetlands that includes several distinct wetlands types. A permanent lagoon receives water from the main river channel, while 3 temporary basins (ephemeral wetlands) connect naturally to the river during periods of high flows (50GL and above coming across the South Australian border). A stormwater lagoon receives rainfall run-off from the township.
Why is Martin Bend wetland complex important?
The Martin Bend wetland system is a site of significant ecological value, providing important habitat for a variety of local native species. Vegetation communities including river red gum, tea tree, black box, and lignum shrub land surround the wetlands. The ecosystem is also home to a diverse range of wildlife, including fish, frogs, mammals, birds and reptiles. Small bodied native fish, tadpoles, and several Murray River turtle species have been recorded in the wetland waters at Martin Bend. Bird species such as the superb fairy wren, Australian reed warbler, little pied cormorant, and black swans are often spotted. The wetlands at Martin Bend are also home to a variety of Riverland frog species, and even the occasional rakali (native water rat) or two.
Why does Martin Bend require human management?
River regulation has caused many of the region’s wetlands to become either too wet or too dry from becoming permanently connected or disconnected to the river, impacting the ecological health and condition. The permanent and temporary wetlands at Martin Bend require management to mimic natural wetting and drying patterns to help improve their condition and increase biodiversity by supporting vegetation growth and native species.
Why is the Martin Bend permanent lagoon dry at times?
The Murraylands and Riverland Landscape Board’s wetlands team manages the permanent lagoon by operating a regulating structure to periodically disconnect it from the river channel, causing the wetland to dry out. Short, dry phases are an important part of the wetland’s cycle, mimicking the naturally dry periods that occurred before river regulation. The regulating structure at Martin Bend has aluminium stop logs which are used to stop water from entering the wetland during a planned dry phase. The drying cycle provides the wetland with many benefits, including removing carp (an introduced species), allowing sediment to settle, and preventing river red gums from becoming permanently water logged.
After a dry period, the wetland is slowly refilled at a rate of 3-5 cm of water per day. The regulating structure is fitted with screens that prevent carp from re-entering wetland, improving the benefits of the dry phase as carp are unable to disturb the sediment which makes the water turbid and dirty. When timed right, refilling a wetland results in improved water quality which in turn improves conditions for local aquatic plants, birds, fish, turtles, and frogs.
Why is water pumped into the temporary basins?
A portable pump is used to deliver environmental water to the temporary basins between high flow events. This allows the basins to receive enough water to support established vegetation such as black box trees and lignum, and support the on-going growth of river red gum and black box saplings. Pumping also prevents large bodied, non-native fish (particularly carp) from entering which improves water quality and creates favourable conditions for native plants and animals.
Water delivered to wetlands for this process is known as environmental water, which provided by the Commonwealth Environmental Water Office (CEWO). Watering is carefully managed to ensure that the health of our wetlands, river system, and also the river community, all benefit.
How do you know if the wetlands are healthy?A healthy freshwater wetland will have water that is low in salt and pollutants, and support a rich diversity of native plant and animal species. Regular wetland monitoring in the form of ecological surveys are conducted to provide a good picture of overall wetland health.
Over spring and autumn months, targeted wildlife monitoring is conducted for fish, bird, and frog populations. During these surveys, the presence of different species is noted and how many are found. Monitoring wetlands helps to keep an eye on the diversity and abundance of species, informing management decisions if there’s any sudden or gradual changes in the system. Invasive plant and animal species also influence the health of a wetland. In particular, the presence of carp is closely monitored when assessing wetland health.
Water quality is measured through surface water and groundwater testing. These assessments provide information about salinity, pH, dissolved oxygen, and turbidity.
The information from all assessments is compared with data from previous years to track the health of a wetland and take note of any changes.
How can I help with conservation efforts at Martin Bend?
Become a citizen scientist!Citizen science is the involvement of community members in scientific research that generates new knowledge or understanding. It offers a range of opportunities to assist in gathering environmental information whilst engaging the community and incorporating local and cultural knowledge.
The Murraylands and Riverland Landscape Board has a variety of citizen science projects which enable participants to share their local knowledge and contribute to landscape management.
TurtlesTurtles play a key role in freshwater systems. One particular function they perform is keeping waterways clean and cycling nutrients in freshwater ecosystems. Known as the ‘vacuum cleaners of the river’, turtles remove fish carcasses from the water up to five times faster than natural decomposition, helping to keep the river clean.
The Murraylands and Riverland region is home to 3 species of turtle:
Murray short-necked turtle - Emydura macquarii
Eastern long-necked turtle - Chelodina longicollis
Broad-shelled turtle - Chelodina expansa
Martin Bend is a popular location for turtle nesting but unfortunately predation is an issue. Members of the community are encouraged to report any sightings of turtles and nests through TurtleSAT. All data collected helps improve knowledge about the numbers and locations of the species, and how to protect them.
The most common species at Martin Bend are the spotted grass frog, Peron’s tree frog, long-thumbed frog, Eastern banjo frog and the Eastern sign-bearing frog.
The FrogSpotter mobile app is designed to make it easy and fun to learn about South Australia’s frogs and to collect essential information about them. By taking part in frog surveys, you can help to improve knowledge about the condition of the environments that frogs are dependent on. Simply submit your frog call via the app. Don’t worry if you can’t identify which frogs are callings –experts will verify them for you! The best time to record frog calls is 30 minutes after sunset on a warm, still night, just after or before it rains.