Freshwater wetland ecosystems fact sheet | Field of Mars EEC

What are freshwater wetland ecosystems?

Freshwater wetlands are ecosystems where fresh water covers the land, fills shallow depressions or keeps the soil wet for long enough to shape the plants and animals that live there. They may be wet all year, wet for part of the year or dry out between periods of rain and flooding.

Freshwater wetlands include places such as swamps, marshes, lagoons, floodplain wetlands, shallow lakes, wet meadows and wet areas beside rivers and creeks. They are different from mangroves and coastal salt marshes because they are mainly shaped by fresh water rather than tides and salty water.

A freshwater wetland is more than just water. It is an ecosystem where living things such as reeds, sedges, algae, frogs, turtles, insects, fish, birds, fungi and bacteria interact with non-living features such as water, mud, sunlight, temperature, oxygen, nutrients and changing water levels.

A freshwater wetland ecosystem.

Freshwater and partly freshwater wetlands, rivers and lakes in Myall Lakes National Park provide water, shelter and breeding habitat for many plants and animals.

Where are freshwater wetland ecosystems found?

Freshwater wetlands are found across NSW in coastal, inland and higher-elevation landscapes. They can occur beside rivers and creeks, on floodplains, in low-lying depressions, in shallow lakes, in swamps, in lagoons and in places where water stays on or near the surface for long enough to support wetland life. Important freshwater and partly freshwater wetlands in NSW include the Macquarie Marshes north of Warren, the Gwydir Wetlands near Moree, Narran Lake Nature Reserve in north-western NSW, Myall Lakes on the north coast and Fivebough and Tuckerbil Swamps near Leeton.

Closer to Sydney, freshwater wetlands and lagoons occur in national parks, reserves and urban catchments. Longneck Lagoon in Scheyville National Park is a freshwater lagoon in western Sydney, and Hunter Wetlands Centre near Newcastle is part of the Hunter Estuary Wetlands Ramsar site, which includes restored freshwater ponds and marshes as well as other wetland types. At Field of Mars Reserve, smaller wet areas, creeklines and water habitats help students compare local freshwater habitats with larger freshwater wetland ecosystems across NSW.

Longneck Lagoon in Scheyville National Park is a freshwater wetland in north-western Sydney.

What living and non-living features make up freshwater wetland ecosystems?

Living features of freshwater wetlands include plants, algae, fungi, bacteria, invertebrates, frogs, fish, reptiles, birds and mammals that use wetland edges. Wetland plants such as reeds, sedges, rushes and aquatic herbs provide shelter, nesting places, food and surfaces where tiny organisms can grow.

Non-living features include water depth, water movement, mud, wet soil, dissolved oxygen, nutrients, sunlight, shade, temperature, rainfall, evaporation and landform. These features change over time, so a freshwater wetland can look very different after heavy rain, during drought or when plants grow thickly through shallow water.

Macquarie Marshes Nature Reserve has living features such as wetland plants and non-living features such as water, mud, sunlight and landform.

What plants and animals live in freshwater wetland ecosystems?

Freshwater wetland plants are adapted to wet ground, shallow water and changing water levels. Common plant groups include reeds, sedges, rushes, spike-rushes, water couch, aquatic herbs and floating or submerged plants. Paperbarks, swamp she-oaks and other wetland-edge trees may grow around some wetlands, especially where the wetland connects with creeklines, floodplains or forested wet areas.

Many animals use freshwater wetlands for feeding, shelter and breeding. Frogs lay eggs in water and tadpoles grow there. Dragonfly and damselfly nymphs hunt underwater before becoming flying adults. Ducks, moorhens, herons and other waterbirds feed in shallow water and among wetland plants. Freshwater turtles, fish, snails, worms and many small invertebrates are also part of wetland food webs.

Wetland plants provide food, shelter and surfaces for small animals, eggs and algae.

How do living things depend on freshwater wetland ecosystems?

Freshwater wetlands support food chains and food webs. Aquatic plants and algae are producers because they use sunlight to make their own food. Tadpoles, snails, insects, ducks and other animals are consumers because they eat plants, algae or other animals. Fungi, bacteria, worms and other decomposers break down dead plants and animals, returning nutrients to the wetland.

Changing water levels can trigger plant growth, insect life cycles, frog breeding and waterbird feeding or nesting. When wetlands dry and refill, seeds, eggs, larvae and animals respond in different ways. This makes freshwater wetlands dynamic ecosystems where water, timing and interdependence are very important.

Pacific black ducks and other waterbirds feed in shallow freshwater habitats.

How are freshwater wetland ecosystems connected to Aboriginal Peoples and Country?

Freshwater wetlands are part of Country. Across Australia, wetlands hold cultural, spiritual, historical and practical importance for Aboriginal Peoples. They can provide fresh water, food, fibre, plants, animals, travel routes, gathering places, teaching places and places connected with caring for Country.

Wetland knowledge is specific to Peoples, places and communities. In NSW, places such as Narran Lake on Yuwaalaraay/Euahlayi Country show how freshwater wetlands can hold deep cultural significance as living water places. Where learning is connected to a specific wetland, local Traditional Custodians should be acknowledged and consulted.

Narran Lake Nature Reserve is an internationally important inland wetland on Yuwaalaraay/Euahlayi Country.

Why are freshwater wetland ecosystems important?

Freshwater wetlands are important because they support biodiversity. They provide food, shelter, breeding places and nursery habitats for plants and animals, including frogs, waterbirds, turtles, fish and many invertebrates. They also help students observe food webs, adaptations, water quality, life cycles and the connections between living and non-living things.

Healthy wetlands can help slow floodwater, trap sediment, filter pollutants, absorb nutrients, recharge groundwater and store carbon. In cities and suburbs, freshwater wetlands and water-sensitive habitats can also improve local biodiversity and help people learn how stormwater, plants, soil and wildlife are connected.

Healthy freshwater wetlands support biodiversity, water quality and learning.

What threatens freshwater wetland ecosystems?

Freshwater wetlands can be damaged when natural water flow is changed by drainage, dams, water diversion, floodplain changes or urban development. Some wetlands dry out too often, stay wet for too long or receive water at the wrong time for plant growth, frog breeding or waterbird nesting.

Other threats include clearing, filling, trampling, erosion, polluted stormwater, excess nutrients, sediment, rubbish, weeds, pest animals, introduced fish and climate change. In urban catchments, water carrying fertiliser, soil, oil, chemicals, leaves and litter from streets and drains can reduce water quality and affect wetland food webs.

Invasive aquatic weeds such as alligator weed can spread through freshwater wetlands and reduce habitat quality.

How can you help protect freshwater wetland ecosystems?

You can help protect freshwater wetlands by staying on tracks, keeping out of wetland water and mud, leaving plants, rocks, logs, leaf litter and animals in place, and observing wildlife quietly from the edge. Photos, sketches and field notes are better than collecting living things.

At school and at home, keep rubbish, soil, fertilisers, chemicals, paint, oil and garden waste out of gutters and drains. Plant local native species around suitable ponds and wet areas, avoid releasing aquarium plants or fish, keep cats contained and dogs under control, and join supervised bushcare, litter removal or waterway projects where appropriate.

Staying on tracks and boardwalks helps protect wetland plants, soil and shallow water.

Related fact sheets

Environments and ecosystems

• Ecosystem and environment fact sheets⁠ – Browse Field of Mars EEC fact sheets about ecosystems, environments, food webs and interdependence.
• River and creek environment fact sheet⁠ – Compare still freshwater wetlands with flowing freshwater environments.
• Field of Mars Reserve fact sheet⁠ – Learn about local bushland, creeklines, wetlands, mangroves and habitats near Field of Mars EEC.
• Coastal salt marsh ecosystem fact sheet⁠ – Compare freshwater wetlands with tidal wetlands shaped by salt water.

• Mangrove forest ecosystem fact sheet⁠ – Explore a tidal wetland ecosystem where freshwater and salt water meet.

Habitats connected to freshwater wetlands

• Water habitats fact sheet⁠ – Learn about ponds, creeks, puddles and wet areas used by freshwater animals.

• Habitat fact sheet⁠ – Learn how living and non-living features create places where organisms can survive.

Plants that support wet places

• Paper-bark tree fact sheet⁠ – Learn about a wetland and creekline plant that provides shelter and habitat.
• Swamp she-oak fact sheet⁠ – Explore a tree that can grow near creeks, estuaries and low-lying wet places.

Animals that use freshwater wetlands

• Eastern snake-necked turtle fact sheet⁠ – Discover a freshwater turtle that lives in wetlands, creeks and ponds.
• Dusky moorhen fact sheet⁠ – Learn about a waterbird that feeds and nests around wetlands and ponds.
• Pacific black duck fact sheet⁠ – Explore a common duck often seen in ponds, creeks and wetlands.
• Striped marsh frog fact sheet⁠ – Learn about a frog that breeds in still or slow-moving freshwater.
• Common eastern froglet fact sheet⁠ – Discover a small frog found near damp ground, ponds and drains.

Food webs and ecological relationships

• Dragonfly fact sheet⁠ – Learn about an insect with aquatic young and flying adults.
• Damselfly fact sheet⁠ – Compare another freshwater-linked insect with underwater nymphs.
• Mosquito fact sheet⁠ – Learn about an insect whose larvae live in still or slow-moving water.
• Invertebrate fact sheets⁠ – Explore small animals that support food webs, decomposition and nutrient cycling.

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