Efficiency of the SASS4 rapid bioassessment protocol in determining river health: a case study on the Mhlathuze River, KwaZulu-Natal, South Africa

Abstract

The purpose of the study was to verify the ability of the South African Scoring System version 4 (SASS4), to assess the health of aquatic ecosystems. The macroinvertebrate community attributes of the Mhlathuze River (KwaZulu-Natal, South Africa) were studied by applying the SASS4 rapid bioassessment method. In testing the effect of spatial and temporal variability in community structure on SASS4 scores it was found that there was a stronger spatial than a temporal effect. It was determined that of the indices used in association with SASS4, the biotic indices (average score per taxon, total score and number of taxa) reflected changes in community structure, but the abiotic habitat quality index did not. It was found that qualitative family-level data provided an adequate classification of sites for use in routine biomonitoring. Ambiguous results were obtained with respect to the importance of measuring abundance during routine biomonitoring. No definite conclusion with respect to the ability of the SASS4 to reflect physical-chemical water quality changes could be drawn from the results obtained in this study. SASS4 was able to reflect the effect of the tidal push from the Mhlathuze Estuary, but this marine influence probably masked less pronounced effects exerted by the remainder of the physical-chemical variables that were investigated.

Rapid bioassessment of the effects of repeated rotenone treatments on invertebrate assemblages in the Rondegat River, South Africa

“…In particular, the insect orders Ephemeroptera, Plecoptera and Trichoptera play crucial roles as they are sensitive to perturbations in water quality (Madikizela and Dye 2003;Dallas 2004;Vinson et al 2010). The ISO-certified SASS rapid bioassessment protocol has been used throughout South Africa (Chutter 1995;Dallas 1997;Dickens and Graham 2002;Vos et al 2002) and within the CFR for this purpose (Dallas 2004(Dallas , 2013. The SASS5 [South African Scoring System, version 5] method (Dickens and Graham 2002) is similar to many other rapid bioassessment techniques such as RIVPACS (Wright et al 1984), IBMWP (Alba-Tercedor et al 2002) and SIGNAL (Chessman 1995) in that it assesses…”

Determining the possible application value of diatoms as indicators of general water quality: a comparison with SASS 5

“…SASS 5 index scores did not show any significant correlation with any specific water quality variables. This lack of significant correlation was not unexpected as attempts, which have been made to find direct correlation between SASS4 results and water quality variables have, so far, been unsuccessful (Vos et al, 2002). Table 6 shows the regression results of the multiple regression performed on the physical and chemical variables and the SASS 5 index scores.…”

Do SASS5 scores vary with season in the South African highveld? A case study on the Skeerpoort River, North West province, South Africa

“…However, in Mpumalanga Province, when using the SASS4 method the SASS score, number of taxa, and ASPT were not significantly different between seasons (Dallas 2004). By contrast, SASS4 data from the coastal lowlands of KwaZulu Natal showed temporal variation (Vos et al 2002).…”

“…Based on the results of earlier studies using the SASS4 method (e.g. Dallas 2004;Vos et al 2002), it was predicted that SASS5 metrics would vary between seasons due to the associated changes in environmental conditions and aquatic invertebrate phenology.…”