Rapid bioassessment techniques used for aquatic macroinvertebrate and plants in wetlands were tested in New South Wales, Australia. Wetlands surveyed ranged from coastal wetlands in the North and Central parts of the State, to tableland wetlands west of Sydney. Wetlands varied in dominant vegetation, hydrology, substrate and level of human impairment. Different options for sampling (mesh size, live-picking times, quadrat size, number of samples or quadrats) and analysis (taxonomic resolution, transformations, biotic indices, multivariate and univariate analyses) are compared to determine optimal sampling effort and evaluate the effects of errors or variability. Results show that, for wetlands of New South Wales, sampling procedures developed and tested in streams and other regions of Australia may not be the most efficient. Using the data from 21 wetlands in New South Wales, a number of analytical techniques were evaluated for the effects of errors. Results show that species-level multivariate analysis is more sensitive in detecting less obvious differences between wetlands (i.e., small effect sizes), while family-level analyses are more appropriate for large effect sizes. A modified waterplant index was developed that is simpler and has a wider application than the other Australian options available. Inherent problems in each index tested were addressed. The results show that the process of summarising a large amount of information into a single value will result in the loss of both information and variability between samples and this cumulative effect of error may effect the assessment of wetland condition. The practical outcome of this thesis is a set of standardised steps to assess wetland quality using biological assemblages. The results show that protocols and indices for rivers are not directly transferable to palustrine, vegetation dominated wetlands. I present protocols that are more appropriate to wetlands and recognise that each protocol would need to be adapted for each wetland type. Despite the need for flexible protocols, I promote the need for a standard approach to wetland sampling and the need for consideration of the effects of errors in sampling designs. This study highlights the need for more research on the response of specific stressors to wetlands flora and fauna. The results from this study also show that wetland macroinvertebrates and plant communities can be used as surrogates in multivariate analyses for detecting large differences between wetlands (wetland types) but that impact assessment requires more detailed investigations including species identification and careful consideration of the choice of reference and control sites. In conclusion I emphasise the need for scientific rigour in the use of biological indicators and consideration of the effects of errors and implications to sampling designs. / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:ADTP/182461 |
| Date | January 2006 |
| Creators | Ling, Joanne Elizabeth, University of Western Sydney, College of Health and Science, School of Natural Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
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