Aquatic invertebrate community structure of selected endorheic wetlands (pans) in South Africa

Shallow wetlands, such as pans, are not well studied in South Africa, even though they perform many important functions, such as providing an important food source for migratory birds and habitat to highly specialized fauna. Aquatic invertebrate diversity, abundance, and water quality in pans were analysed seasonally from 3 provinces in South Africa with contrasting climates. Univariate and multivariate statistics were used to assess similarities in aquatic invertebrate communities and water chemistry among pans. Pans inundated for extended periods had greater aquatic invertebrate diversity, and several of these taxa were not adapted to the temporary environment common to pans. The subtropical region had greater aquatic macroinvertebrate diversity than semiarid regions due to more rainfall per annum in the subtropical region. Water temperature was a major driving factor for diversity, with greater diversity occurring in warmer seasons. High water hardness and salinity were found to drive decreased diversity and encourage the presence of hardy and more tolerant species. Understanding the importance of these aforementioned factors (i.e., pan longevity, temperature, water hardness, and salinity) influencing aquatic invertebrate biodiversity in pans provides a baseline for future studies and impact assessments on these important and understudied systems

The application of a macroinvertebrate indicator in afrotropical regions for pesticide pollution

Many biotic integrity indices are not able to isolate community effects due to pesticide exposure as the communities also respond to other anthropogenic and natural stressors. A macroinvertebrate trait bioindicator system that is pesticide specific was therefore developed to overcome these challenges.This system, called SPEAR (SPEcies At Risk), was applied in South Africa as an indicator to link known pesticide catchment usage to changes in the macroinvertebrate community, especially when analytical methods are inconclusive. In addition, the SPEARsalinity index within the SPEAR suite of tools was also evaluated for its effectiveness in South Africa. The results indicated that all of the sites have either been exposed to the same pesticide pressure or not been exposed to pesticides as the SPEAR results were similar when compared to the pesticide intensity. The interaction with other factors like nutrients or salinity was likely a factor that confounded the SPEARpesticides indicato