Abstract:
Macroinvertebrate assemblages can vary with season as a result of changing environmental
conditions and phenology of individual species. The objective of this study was to determine
whether results from the South African Scoring System version 5 (SASS5) are affected by
season. The standard SASS5 protocol was used to sample three sites on the Skeerpoort River,
South Africa, in autumn, winter and spring 2013, and summer 2014. At each site, stream
morphology was characterised and physicochemical variables were measured. Two-way
analysis of variance (ANOVA) was used to compare SASS indices in relation to site and
season, and a one-way ANOVA was used to test the effect of season using both current and
historical data. Macroinvertebrate assemblage similarity of sites was determined using nonmetric
multidimensional scaling ordination, followed by analysis of similarity. Whilst
macroinvertebrate assemblages differed between seasons and sites, there was no seasonal
variation in the values of SASS indices, but they did differ between sites. SASS5 appears to
be robust to seasonal variation in macroinvertebrate assemblage and seems suitable for use
throughout the year in a perennial river draining the South African highveld region.
