2007 Wetland Inventory for the Eyre Peninsula

20.3 Temporary WetlandsMany of South Australia’s inland wetlands are temporary and display slightly different invertebrate faunacomposition from other wetland systems (saline lakes or permanent waters) Williams (2000) makes fourgeneral conclusions from his study of temporary wetlands.1. Faunal diversity is high and often higher than in many permanent wetlands.2. A wide range of fauna groups occurs, the particular assemblage depending largely upon time fromfilling. Many species are restricted to temporary wetlands, for example all notostracan, conchostracanand anostracan species are restricted to temporary wetlands.3. Local differences in hydrology, filling frequency, basin shape and other factors often result in differencesbetween wetlands in the same area and same time.4. Considerable continental and regional endemism prevails. Most macofaunal species are endemic toAustralia.The filling or flooding of temporary water bodies realises a pulse of nutrients that, together with light andwater, provide the resources for germination and growth of both micro and macro photosynthesizers.Habitat for consumers and decomposers soon follows. The invertebrate sediment egg bank withdesiccation-resistant stages seems to be the initial source of colonists. The groups that tend to be first intemporary waters include rotifers, ostacods, copepods and cladocerans.When the water body starts to dry a ‘predator soup’ results, and terrestrial predators (eg birds) come to thewater to feed during the drying process. This process forms a critical trophic link between aquatic andterrestrial systems (Boulton and Brock, 1999).20.4 AnalysisThirty-three sites were surveyed with 18 sites returning invertebrate sample results. The remaining 15 sitesdid not have invertebrates present; these are hyper saline wetlands that do not support micro invertebrates,or had water levels that were to low too retrieve samples. Overall species composition, richness and trophicstructure is quite deficient in wetlands surveyed on Eyre Peninsula.20.4.1 Invertebrate abundanceTable 1 illustrates the invertebrate abundance sampled within the 18 survey sites. Twenty-three specieswere recorded in total. The average abundance of species within each wetland is approximately fourspecies. Abundance levels varied from one species to 14 species, with three species showing substantiallyhigher frequency of occurrence than the other 15 species. Two of these species are from the familyOstracoda (Candonocypris sp. and Diacypris cf. spinosa) and the other Daphniopsis pusilla is from thefamily Cladocera. Both families are widely distributed and common, occurring within inland waters fresh andsaline. Ostracods vary in form, some being swimmers, clingers, climbers or burrowers. Cladocerans usuallylive on the substrate where they feed on fine particulate matter, others are mainly free-swimming andconstitute an important part of the plankton of the open water (Williams 1980). Cladocerans are also animportant food for zooplanktivorous fish. Their nutritional value is high, they are in particular rich in essentialhighly unsaturated fatty acids and natural anti-oxidants.28