Teleosts, agnathans and macroinvertebrates as bioindicators of ecological health in a south-western Australian river

摘要

Using standardised techniques to assess bioindicator groups from different food-web levels, the study aimed to provide an ecological baseline upon which monitoring of future changes in the aquatic ecological condition of the Warren River could occur. It also aimed to provide a review of the endemic freshwater fishes of south-western Australia in terms of their appropriateness as indicators of secondary salinisation. Fish and macroinvertebrate communities of the Warren River are described from historical and unpublished data and from sampling during 2006. The Warren River was found to be an important system in terms of freshwater fish conservation housing six of the eight endemic freshwater fishes of south-western Australia and is an important breeding and nursery ground for the Pouched Lamprey (Geotria australis). Many of these fishes are potential bioindicators of ecological impacts of salinisation of this and other rivers of the region. The relatively low SIGNAL 2 macroinvertebrate scores at the reference sites suggested that the communities in the main channel of the Warren River were generally those classified as tolerant of pollution. However, a small increase in the pollution sensitive taxa was recorded moving downstream with the most upstream (salinised) site (in the cleared section of the catchment) having the lowest composite and mean SIGNAL 2 score. The use of bioindicator groups from multiple levels of the aquatic food web should be more widely used in assessing and monitoring riverine health in south-western Australia; particularly with regards to the impact of secondary salinisation.