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Water for the environment: wetlands |
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The Aquatic Invertebrates of NSW Wetlands
Aquatic invertebrates include insects, crustaceans, molluscs and worms. They are commonly referred to as water bugs. All are animals without backbones. They are also characterised by the fact that they spend part or all of their life cycles in water. They range in size and may or may not be visible to the naked eye. (Davis and Christidis, 1997). [ TOP ] Aquatic invertebrates are ubiquitous in freshwater environments in NSW. Wetlands provide a range of habitats for aquatic invertebrates. They include the water surface, the water column, the bottom sediments and substrates, and aquatic vegetation. The following categories are often used to group invertebrates on the basis of the micro-habitats they occupy within a wetland. Zooplankton is often used to describe those animals that float on the water surface or drift within the water column. Nekton is the term used to describe those invertebrates that are able to swim. Nekton are usually found in the upper water column. Benthos is the term used to describe those invertebrates that live on or within the bottom sediments or substrates (Davis and Christidis, 1997). [ TOP ] Aquatic invertebrates are responsible for a large part of the secondary production that takes place in wetlands. They are part of both the detrital and grazing food chains. Those in the detrital food chain (called detrivores) feed on dead and decaying plant and animal matter, and are therefore particularly important in the breaking down and cycling of organic material. Detrital feeders are usually the first to appear in a newly flooded wetland, because detritus is immediately available as a food source. Those in the grazing food chain consume aquatic vegetation and algae, which helps to maintain water quality. Others are predators feeding on other invertebrates (Davis and Christidis, 1997). In turn, aquatic invertebrates are an important food source for fish, amphibians and waterbirds. Many aquatic animals rely on the vast amounts of microscopic food that are available in wetlands. Aquatic invertebrates can be useful in biological monitoring (that is, the use of biological data as an indicator of water quality) due to their:
An understanding of the range and importance of aquatic invertebrates is an essential component in the conservation and management of wetland ecosystems. [ TOP ]
Legislation that provides for the protection, conservation and recovery of all threatened fish and marine plants in NSW was included as Part 7a of the Fisheries Management Act in July 1998. Fish are actually defined within the legislation as all aquatic animals at any stage in their life cycle. The Act therefore provides for the protection of threatened aquatic invertebrates. Three aquatic invertebrates, the River snail (Notopala sublineata) from the Barwon-darling River, Adams emerald dragonfly (Archaeophya adamsi), and Buchanans fairy shrimp (Branchinella buchananensis) , have been listed under the legislation. Further information on the Threatened species legislation can be obtained by contacting NSW Fisheries. [ TOP ] Several species of mosquitoes are known vectors of arboviruses (ARthropod BOurne VIRUSES). For more information on this issue, please refer to the "Some Specific Wetland Issues and Management Responses" page of this site. Some snails (Lymnaeidae) are hosts in the life-cycle of the sheep liver fluke Fasciola hepatica. Ingestion of this fluke by sheep and cattle can lead to death. Other aquatic insects are not usually harmful, but they can be a source of irritation, particularly to humans. [ TOP ]
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** References most suitable for school children Common, I.F.B. & Waterhouse, D.F. 1981. The Butterflies of Australia. Angus and Robertson, Sydney. CSIRO. 1991. The Insects of Australia, Vols 1 & 2. Melbourne University Press, Carlton. ISBN 0 522 84454 5. Description: Provides keys to the identification of all families of aquatic and terrestrial insects known to occur in Australia. Also provides information on insect anatomy, systematics and biogeography. Davis, J. and F. Christidis. 1997. A Guide to Wetland Invertebrates of South-Western Australia. Western Australian Museum, Australia. Harvey, M.S. and Yen, A.L 1989. Worms to Wasps: An illustrated guide to Australia’s terrestrial invertebrates. Oxford University Press, Melbourne. Description: Primarily a guide to Australia’s terrestrial insects but also describes groups with aquatic members. Hawking, J.H. 1994. A preliminary guide to keys and zoological information to identify invertebrates from Australian freshwaters. Taxonomic Workshop, Murray-Darling Freshwater Research Centre, 15-17 February, 1994. Description: Has been updated in recent years. Hawking, J.H. 1998. A guide to keys and zoological information to identify invertebrates from Australian freshwaters. Identification Field Guide No. 2. Taxonomic Workshop, Co-operative Centre for Freshwater Ecology.. Description: The most recent and comprehensive list of keys for Australian freshwater invertebrates. **Hawking, J.H. and F.J. Smith. 1997. Colour Guide to Invertebrates of Australian Inland Waters. Co-operative Research Centre for Freshwater Ecology Guide No. 8. Co-operative Research Centre for Freshwater Ecology. ISBN 1 876 144 09 2 Description: Designed for use in the field. Very easy to use, with lots of photos. Ingram, B.A., J.H.Hawking and R.J. Shiel. (1997). Aquatic Life in Freshwater Ponds: A Guide to the Identification and Ecology of Life in Aquaculture Ponds and Farm Dams in South-Eastern Australia. Co-operative Research Centre for Freshwater Ecology, Albury.Jones, D. and G. Morgan. 1994. A Field Guide to Crustaceans in Australian Waters. Reed Books, Australia. ISBN 0 7301 0403 6 Maher, M. 1983. Invertebrates. In "Wetlands in New South Wales". (Ed C. Haigh). National Parks and Wildlife Service, NSW. ** Miller, R. 1983. Freshwater Invertebrates. Gould League of Victoria. Globe Press. Victoria. ISBN 0 909858 49 7 Description: A good basic guide for the identification of Australia’s aquatic invertebrates. A good book to use with students. Ponder, W.F., S.A. Clark and M. J. Dallwitz. 2000. Freshwater and Estuarine Molluscs. An interactive Key Illustrated for New South Wales. CD Rom. CSIRO Publishing. ** Slater, P. and Parish, S. 1997. A First Field Guide to Australian Insects & Spiders. Steve Parish Publishing, Brisbane. Williams, W.D. 1980. Australian Freshwater Life. 2nd Edition. MacMillan, Melbourne. ISBN 0 333 29894 2 Description: Provides comprehensive information on the common invertebrates of Australian inland waters. This book has, for many years, been the principle book for macroinvertebrate field work and high order taxonomic identification. Some areas of this book are now outdated. Williams, W.D. 1983 Life in Inland Waters. Blackwell, Melbourne. Zborowski, P. and Storey, R. 1995. A Field Guide to Insects of Australia. Reed Books, Chatswood, NSW. Description: Provides a useful introduction to the orders of Australian insects. Includes many groups which occur in aquatic environments.
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