Applying conservation assessment to Australian rivers : a case study using macroinvertebrates

Interest is growing among river managers in the conservation values of rivers, and in the protection of rivers of high ecological value. But can the concepts of conservation value established for terrestrial ecosystems be transferred to riverine ecosystems? What special features of riverine systems should be addressed in determining approaches to assessment and protection? The thesis uses a case study of the assessment of conservation values of stream macroinvertebrates to explore these questions. Four conservation criteria widely used in the assessment of flora and fauna of terrestrial ecosystems were used. These criteria are: rarity, diversity (richness), representativeness and biogeographic values. A field survey of 44 sites in two regions of Tasmania provided data to test these criteria and to evaluate implications for protection of high conservation value sites. The thesis describes the macroinvertebrate assemblages using family level data, and the Plecoptera are analysed at species level. The four conservation criteria are applied to the data and the sites of high conservation value identified. The conservation assessment process is then subjected to evaluation. A number of issues were identified including: limitations of site-based data; taxonomic issues; distributional information, applying thresholds, integrating with existing data sources including the Monitoring River Health database, and establishing representative assemblages. The assessment process was determined to fulfill most quality standards but fell notably short on an adequate assessment of the conservation values of riverine systems. Implications of the study are discussed within the broader context of conservation assessment and protection for riverine ecosystems in Australia. Possible strategies available for the protection of sites of high value identified in the field study are identified. A model for the assessment of riverine ecosystems is proposed and future directions in protection are explored