Assessing fish and macroinvertebrates assemblages in relation to environmental variables in Makuleke floodplain pans: implications for biodiversity conservation.

Abstract

Floodplain wetlands remain important habitats for most macrophytes, macroinvertebrates, birds, fish, amphibians, wildlife and in particular large mammals. They are dynamic in nature and provide many ecosystem services even to humans. The present study was undertaken to assess water and sediment chemistry as drivers of macroinvertebrates and fish communities in Makuleke floodplain wetlands in north Kruger National Park, South Africa. Water, sediments, macroinvertebrates and fish samples were collected across different hydroperiods (i.e., Low water period and high water period) from six floodplain pans. Macroinvertebrates were dominated by (Notonectidae, Libellulidae, Gerridae, Chironomidae larvae, Belostomatidae, gomphidae, dytiscidae and Baetidae, while fish were dominated byTilapia sparminii, Gambusia affinis, Coptodon rendali, Oreochromis hybrid, Oreochromis mossambicus, Enteromius palludinosus and Clarais gariepinus. Generally, fish and macroinvertebrate abundances and diversity were elevated during high water levels as compared to low water levels, suggesting that hydroperiod plays a significant role in structuring aquatic faunal communities. Redundancy and canonical– correlation analysis identified salinity, TDS (water) and Zn, C and B concentrations (sediment) as the major drivers of macroinvertebrate community structure, while pH, TDS (water), and K, Ca and Mg concetrations (sediment) were the major drivers of fish communities. In addition, pelagic chlorophyll –a was strongly positively associated with fish, particularly Gambusia affinis, during the high water level period. The results of this study provide important baseline information on the ecology of the Makuleke pans.