Wetlands also acts as natural sponges, absorbing and stilling flood waters and filtering out sediments, nutrients and other pollutants.
A century ago, wetlands were found in most of the bays and coves up and down the Derwent. Most of these wetlands were filled in over time, to make way for buildings, factories, parks and even tips. Today, only a few of these wetlands remain – for example at Goulds Lagoon and Risdon Cove. The Habitat Atlas indicates that there are 1.3 km² of tidal wetlands remaining in the Derwent estuary, particularly in the area between Bridgewater and New Norfolk, where large areas of marshes, reed beds and tidal flats can still be seen.
Did you know?
- Many of the sporting fields along the Derwent foreshore were once wetlands, including at Cornelian Bay, Geilston Bay and Wentworth Park.
Things to explore
- Visit a wetland as part of a school trip, for example at Goulds Lagoon, Risdon Cove, or the man-made Kingston stormwater treatment wetland.
- Download the Wetland Communities E-Set from the Parks & Wildlife website for information and activities.
Plants and animal species of tidal wetlands and macrophytes beds occur in a range of different community types, largely distinguished by the vegetation types.
Wetlands are among the world’s most productive environments yet their continuing loss and degradation is a major global problem. A century ago, wetlands were found in most of the bays and coves up and down the Derwent. Most of these wetlands were filled in over time, to make way for buildings, factories, parks and even tips. Today, only a few of these wetlands remain – for example at Goulds Lagoon and Risdon Cove. The Habitat Atlas indicates that there are 1.3 km² of tidal wetlands remaining in the Derwent estuary, particularly in the area between Bridgewater and New Norfolk, where large areas of marshes, reed beds and tidal flats can still be seen.
There are many threats to tidal and lagoon wetlands of the Derwent estuary, which are common to most wetlands. These include:
- direct damage or loss from land clearing and urban development;
- introduction and spread of weeds and pests;
- alterations to natural water patterns and flows (due to water extraction, barriers, and changing weather patterns);
- local sources of pollution and pollution within the greater catchment (upstream); and
- altered fire regimes.
Macrophytes beds have also been considerably influenced by human actions. Major impacts include:
- impaired hydrology due to reduced river flow rates;
- altered nutrients;
- altered sediment budgets;
- dredging, and
- anchor drag.
While a range of legal, policy and other mechanisms are already in place to deal with these threats, there is a need for a special focus on the management needs of wetlands and macrophytes beds.
Educational resources and excursions
Classroom and outdoor activities
The DEP have developed a range of classroom activities and an outdoor interpretive walk focused on wetlands and macrophyte beds with support from the Australian Government’s Caring for Our Country. The material is suitable for grades K–10. A single classroom activity or the interpretive walk can be presented alone. However, the material has been designed to complement the interpretive walk, and if delivered together will enable students to gain a good understanding of the ecology and importance of wetlands and macrophyte beds to the broader estuary. The aim is to promote aquatic conservation by raising awareness of our impacts on urban waterways, the value of maintaining healthy waterways, and the need for habitat restoration and protection. This project also helps to develop the students listening, writing and recording skills through creating charts, making records of animal’s diet and sensitivity to pollution, thinking about biological processes, and creating visual classroom displays. Many of these activities also help students develop social skills such as working in a team, and considering the need for other creatures and the environment.
Wetland and Macrophyte Introduction Grades 1–10
The DEP website provides a general introduction to tidal wetlands and macrophyte beds in the Derwent estuary. In small groups ask students to explore the website to answer a range of general exploratory questions.
Discovery Cards Grades 1–6
If planning an excursion to wetlands and macrophyte beds (Goulds Lagoon Discovery Trail) undertake this classroom activity before and after the field trip to promote scientific enquiry. Write questions about the habitat to be visited, revisit them in the field, and also when back in the classroom to see if they found the answers.
Wetland Critters in the Classroom – where they live and the effect of pollution Grades K–6
The aim of this activity id to identify the diversity of organisms that live in wetland habitats, and gain an understanding of habitat, in terms of where an organism lives, what it eats, and its requirements for breeding and survival. The activity also raises awareness of the varied impacts on urban waterways, the value of maintaining healthy waterways, and the need for habitat restoration and protection. Two tasks are presented ‘Wetland critters and where they live’, and ‘How does pollution affect wetland organisms and the broader habitat’.
Dragonfly Life Cycle Grades K–6
The most common type of wetland animals are invertebrates, and the most common of these are insects – a diverse and fascinating group of animals that are the base of wetland food chains. Read through info cards with the class, talking through a range of topics including insect anatomy, life-cycles, metamorphosis, and the need for a healthy aquatic environment. Provide time to talk through each card, and perhaps complete the questions and activities along the way. Activities include making dragonflies out of art materials, and drawing dragonfly life cycles and wetland food webs.
Goulds Lagoon Discovery Trail all ages
The Goulds Lagoon Discovery Trail can be enjoyed by individuals, or led by a teacher/guide. Take the Trail by following 10 discovery points along a mapped walking trail and read from a detailed information sheet. Explore the diverse and productive world of wetlands and macrophyte beds to discover underwater grass meadows, water filtering plants, a diverse bird community, water bug community, and the threat of sea level rise, all in one short walk. Incorporate the ‘Wetland Detective’ and ‘Wonderful waterbugs’ activities to engage students further in this outdoor classroom. Currently there is no signage at the site, so it is essential you print out the Discovery Trail info pack and take it with you.
Wetland Detective Grades1–6
After the highly visible animals have been sighted it is useful to consider the wide range of other users of the wetland that cannot be seen. Many animals visit the site only at night, or at certain times of the year. Print out one field sheet per student and hand them out at the start of the Discovery trail. Ask students to fill in the field sheets with a pencil to piece together the users and residents of the wetland by looking closely for signs, tracks and scats.
Wonderful Waterbugs Grades 4–10
Healthy wetlands contain an incredibly abundant and diverse community of microscopic animals. This activity focuses on collecting and looking closely at water samples to appreciate the number and variety of waterbugs that live there. It introduces students to the diversity of tiny animals that live in wetlands, the roles they play in processing nutrients, and their importance as food for larger wetland animals. Supervise students using dip nets and containers to collect and sort waterbugs, and follow identification charts to identify them.