Conserving Freshwater Biodiversity in an African Subtropical Wetland: South Africa’s Lower Phongolo River and Floodplain

Abstract

Freshwater biodiversity is under constant threat from a range of anthropogenic stressors. Using South Africa's Phongolo River and floodplain (PRF) as a study case, the aim of this chapter is to provide an overview of the conservation and management of freshwater biodiversity in a highly diverse subtropical ecosystem. The PRF is the largest floodplain system in South Africa which is severely threatened by irregularly controlled flood releases from a large upstream dam, prolonged drought, deteriorating water quality, organic pollutants and the increasing dependence of the local communities. Based on a decade of survey of the PRF conducted from 2010 to 2020, this chapter highlights the current diversity of aquatic organisms (invertebrates, fishes, frogs and their parasitic fauna), followed by an overview of their biological and physical stressors. The current challenges in the management of the aquatic biodiversity of this region and a way forward to conservation strategies are also addressed in this chapter.

Integrative Morphological and Genetic Characterisation of the Fish Parasitic Copepod Ergasilus mirabilis Oldewage & van As, 1987: Insights into Host Specificity and Distribution in Southern Africa

“…Ergasilus mirabilis was originally described from the leopard squeaker Synodontis leopardinus (Mochokidae) in the Phongolo River, South Africa [29]. However, the distribution of S. leopardinus appears to be restricted to the Kunene, Okavango, and other rivers in the Upper Zambezi system [110], while the only known species of Synodontis in the Phongolo River system is the plain squeaker Synodontis zambezensis (see [111,112]). A year after its description in 1987, E. mirabilis was reported on 16 fish species across various regions in southern Africa, including S. leopardinus from the Phongolo and Zambezi River systems by the same authors [4] (see Table 1).…”

Distribution, abundance, population structures, and potential impacts of the invasive snail, Tarebia granifera in aquatic ecosystems of north‐eastern South Africa

“…Site selection was based on study sites used as part of previous studies in the region (Dube et al., 2017 ; de Necker, 2019 ; de Necker, Gerber et al., 2022 ). The Phongolo River system is the largest floodplain system in South Africa (Acosta et al., 2020 ) and is often the most southern distribution locality for many lowveld tropical freshwater species, making it an ecologically significant area. The Limpopo River is one of the largest rivers (~1750 km) in southern Africa, its basin draining an area of ~415,000 km 2 across South Africa, Botswana, Zimbabwe, and Mozambique (Mosase & Ahiablame, 2018 ).…”

Effects of river regulation on aquatic invertebrate community composition: A comparative analysis in two southern African rivers

“…The lower Phongolo River and floodplain (PRF), located in northern KwaZulu‐Natal, is one of South Africa's largest and most important floodplain ecosystems (de Necker et al., 2021 ; de Necker, Brendonck, et al., 2022 ; de Necker, Manfrin, et al., 2020 ; de Necker, Neswiswi, et al., 2020 ; Dube et al., 2015 , 2019 ). This river and floodplain serve important irrigation, domestic and livestock watering purposes for local communities, while also supporting some of the highest aquatic biodiversity in South Africa (Acosta et al., 2020 ; Smit et al., 2016 ). The PRF is fully dependent on controlled flood releases for fresh water, receiving annual controlled flooding regimes from the Pongolapoort Dam, located upstream of the floodplain (de Necker, Neswiswi, et al., 2020 ; Dube et al., 2015 ) (Figure S1 ).…”

“…These two rivers merge and form a confluence within the NGR. These floodplain habitats are important for the breeding, spawning and foraging of many aquatic biota (Acosta et al., 2020 ; de Necker et al., 2021 ; de Necker, Gerber, et al., 2022 ; van Rooyen et al., 2022 ). As such, both the Phongolo and Usuthu rivers are important to the continued maintenance of biotic diversity and ecological functioning of these floodplain lakes.…”