Typology of arid-zone floodplain wetlands of the Paroo River (inland Australia) and the influence of water regime, turbidity, and salinity on their aquatic invertebrate assemblages

Abstract

Typologies of arid-zone wetlands tend to be based on basin geomorphology, hydrology and vegetation because these parameters are readily surveyed at a broad scale. However, there has been little work confirming that these typologies are relevant at finer scales to aquatic macroinvertebrate and zooplankton assemblages whose composition may be responses to more proximate features of water regime, turbidity, and salinity. Furthermore, the practical difficulties of sampling these wetlands (e.g., distance, harsh working conditions, unpredictable filling) mean that we have little understanding of the interactions among these variables and the effects on the fauna of arid-zone wetlands. Based on several intensive collections trom the Paroo floodplain over a decade spanning highly variable flows, we explore the match between present wetland typologies and invertebrate assemblage structure. Statistical relationships of assemblage structure with salinity, turbidity and water regime indicate differential responses, typical of the temporal and spatial mosaic of wetlands and their filling patterns in this arid zone. Salinity, turbidity and water regime also serve to distinguish among the wetland types on the Paroo River floodplain, indicating that a general typology that applies to vegetation, basin morphology and invertebrate community structure can be used for classification and land management purposes in this arid-zone.