The making of a conservation landscape: the emergence of a conservationist environmental infrastructure along the Kwando River in Namibia's Zambezi region

The Kwando Basin of north-eastern Namibia is firmly embedded in current national and international conservation agendas. It is a key part of the world's largest transboundary conservation area, the Kavango–Zambezi (KAZA) Transfrontier Conservation Area, and the home of seven community-based conservation areas (conservancies) and three smaller national parks (Mudumu, Nkasa Rupara and Bwabwata). While conservation agendas often start from the assumption that an authentic part of African nature is conserved as an assemblage of biota that has not been gravely impacted by subsistence agriculture, colonialism and global value chains, we show that environmental infrastructure along the Namibian side of the Kwando Valley has been shaped by the impact of administrative measures and the gradual decoupling of humans and wildlife in a vast wetland. The way towards today's conservation landscape was marked and marred by the enforced reordering of human–environment relations; clearing the riverine core wetlands of human habitation and concentrating communities in narrowly defined settlement zones; the suppression of specific, wetland-adapted subsistence practices; and the elimination of unwanted microbes with the help of insecticides. The interventions in the ecosystem and the construction of an environmental infrastructure have created a unique conservation landscape in the Namibian Zambezi region, which provides the foundation for its popularity and success.

Take me to the River along the African drought corridor: Adapting to climate change

This paper brings together a wide range of concepts from climate change predictions, palaeoecology, wildlife ecology and sustainable livelihoods in order to prioritise adaptive management measures that are necessary for the conservation of the African megafauna. Climate change predictions emphasise the severe aridity that will surge into southern Africa later this century and must be contrasted with the relatively wetter conditions in eastern Africa. The evolution of African mammals and their adaptive responses to past episodes of climate change is explained by reference to range shifts and movements along Balinsky’s (1962) ‘drought corridor’ that extends from SW Africa northeastwards to Somalia and then westwards across the Saharan-Sahelian zone. The drought corridor today could potentially extend from Kenya southwestward through to Botswana/South Africa and Namibia, via connectivity corridors linking existing wildlife areas, forming the Kalahari-Rift Valley Transfrontier Conservation Landscape (KALARIVA TFCL). The most promising route along the drought corridor links the Chobe – Linyanti – Kwando river systems of Botswana/Namibia with Luangwa Valley in Northern Zambia, along the Zambezi River via Lake Kariba (Matsudonna and Mana Pools) in Zimbabwe. Malawi poses an absolute barrier to such connectivity and by the turn of this Century runs the risk of confining the area to the south almost entirely to the SW arid adapted fauna and that to the north to water dependent ungulates such as elephants, buffalo and zebra. The key movement corridors are identified in a bid to extend the spatial and temporal scale of conservation planning in order to adapt effectively to climate change. The importance of ‘co-existence’ between wildlife and people is emphasised together with the need for local communities to benefit from sharing the KALARIVA TFCL with African wildlife, via new models of conservation financing and management that reward rural African communities for being the true custodians of the African megafauna.

Comparative fish ecology in three periodically connected rivers in the upper Zambezi and Okavango ecoregions

The Upper Zambezi, Kavango and Kwando rivers are three periodically interlinked floodplain rivers which share the same Upper Zambezian floodplain ichthyofauna. The aim of this thesis was to compare the biology and ecology of the fish communities in these three rivers. The objective was to test the hypothesis that fish community composition and assemblage structure, fish diets, food web structure and trophic dynamics, fish growth rates and total mortality are influenced by the differing flood magnitudes of the three rivers, in support of the flood pulse concept. To understand the abiotic characteristics of each river, water temperature, flood regime, total dissolved inorganic nitrogen concentrations and water quality parameters were measured and compared between rivers. Water temperatures varied seasonally, and seven day moving averages peaked above 30 °C in January, and fell to between 16 and 19 °C in June. The Zambezi River had the largest flood (6.14 m), followed by the Kavango River (3.80 m), while the Kwando River had the smallest flood (0.65 m). Total dissolved inorganic nitrogen concentrations were low in the Kavango and Zambezi Rivers (0.2 - 0.6 mg/l), and slightly higher in the Kwando River (<1 mg/l). Conductivity, total dissolved solids and total dissolved inorganic nitrogen concentrations decreased with the flood (dilution effect). Using biomass catch per unit effort data from experimental gillnets, fish community composition and assemblage structure was described, and differed between rivers in all hydrological seasons. In the Zambezi and Kavango rivers, fish assemblages varied with hydrological season as a result of the homogenising influence of the flood pulse, while in the Kwando River fish assemblages did not differ seasonally as flood pulses were small and often irregular. Differences in community composition were attributed to the abundance of Hydrocynus vittatus, a large bodied open water predator, in the Zambezi and Kavango rivers, and its relative absence in the Kwando River. Based on the results of the community composition, six focus species were chosen that were abundant and representative of the various feeding modes and life history strategies of the fish community. These were the striped robber Brycinus lateralis, sharptooth catfish Clarias gariepinus, blunttooth catfish Clarias ngamensis, African pike Hepsetus cuvieri, silver catfish Schilbe intermedius and purpleface largemouth Serranochromis macrocephalus. Stomach contents analysis was then used to compare the feeding ecology of the six example species between rivers. Clarias gariepinus, C. ngamensis and S. intermedius were piscivorous in the Zambezi and Kavango rivers, and preyed upon more invertebrates in the Kwando River, while Hepsetus cuvieri and S. macrocephalus were piscivorous in all three rivers. Differences in diets were attributed to seasonal prey abundance, with prey fishes abundant during falling and low water when the Zambezi and Kavango rivers were sampled, while invertebrates were abundant during rising and high water when the Kwando River was sampled. Prey mastication by B. lateralis made prey identification difficult. For other predators, the usefulness of stomach contents analysis for dietary descriptions was restricted by the high proportion of empty stomachs. As a result, whole ecosystem stable isotope analysis was used to gain a holistic understanding of the food web structure and fish feeding ecology of the three rivers. The Zambezi and Kavango river food webs were supported by C enriched resources such as C4 and C3 riparian vegetation from the floodplain, while the Kwando River food web was based on C depleted resources such as filamentous algae and aquatic macrophytes. The Zambezi River food web had a restricted nitrogen range, with reduced food chain length and the predators in this river did not occupy such elevated trophic positions compared to in the Kavango and Kwando river food webs. This was attributed to the overfishing of the primary and tertiary consumers in the Zambezi River, a phenomenon known to reduce food chain length. Focussing on predator communities, in the Zambezi and Kavango rivers, H. vittatus isotopic niche width was large and overlapped significantly with most other predators, while in the Kwando River predator niches were more distinct. This supported previously proposed hypotheses by describing H. vittatus as a dominant predator which excludes all other fishes by predation or competition. Despite the dominance of H. vittatus, C. gariepinus occupied the position of top predator in all three rivers, and information on the habitat use, feeding habits and trophic niches of the serranochromine cichlids added understanding of their ecology. Lastly, age was determined using sectioned sagittal otoliths for C. gariepinus, C. ngamensis, S. intermedius and S. macrocephalus and using whole asteriscus otoliths for B. lateralis and H. cuvieri, and growth was modelled using the von Bertalanffy growth equation. Growth performance was high in the Zambezi and Kavango rivers, and lower in the Kwando River, most likely in response to the varying flood magnitudes. Total mortality rates, estimated using Hoenig’s maximum-age based equation, were high in the Zambezi River as a result of the high fishing pressure on this river. Overall floodplain fish ecology in the Zambezi, Kavango and Kwando rivers was influenced by the flood pulse, as was predicted by the flood pulse concept. Periodic and equilibrium life history strategists were found to adapt either to the pulsing environments of the Zambezi and Kavango rivers, or to the more stable environment of the Kwando River, and large bodied, long lived periodic strategists such as C. gariepinus tended to be highly plastic and able to thrive in most conditions. Data also suggested that Zambezi River food web structure and fish mortality rates have been impacted by overfishing, for which more information is needed to conserve and manage this system.

Sexual selection by female choice prevents speciation reversal in a hybridizing trio of mormyrid fish in southern Africa: evidence from playback experiments of electric organ discharges

We studied the question of whether or not female choice among variant forms of species-specific male advertising signals, electric organ discharges (EODs), is a factor in preventing panmixy in a parapatric sibling complex of three species of mormyrid fish, inhabiting three parallel rivers in southern Africa. The three species’ EODs are characteristically differentiated in waveform. The Upper Zambezi River is inhabited by Pollimyrus marianne Kramer, van der Bank, Flint, Sauer-Gürth & Wink, 2003, the Okavango River by P. castelnaui (Boulenger, 1911), and the smaller Kwando River in their middle by P. cuandoensis Kramer, van der Bank & Wink, 2013, which is their hybrid species of unidirectional origin. P. castelnaui females ( out of 5) and P. marianne females ( of 5) responded stronger to playback of the EODs of male conspecifics compared to those of male P. cuandoensis. Pollimyrus castelnaui and P. marianne females neither preferred nor discriminated against the male EODs of each other’s species, respectively (one exception). The single P. cuandoensis female available preferred a P. marianne male EOD over one of its own species, and was neutral in all other tests. This suggests that female resistance in the two main system species to P. cuandoensis male EODs is an evolved one, effectively limiting hybridization to the Kwando. The females of the two main system species, P. castelnaui and P. marianne, thus prevent panmixy in the Okavango and the Zambezi, respectively, thereby keeping up the three-sibling species complex by discriminating female choice against P. cuandoensis males in the Okavango-Kwando-Zambezi system.

Livelihood activities in a Namibian wildlife conservancy: a case study of variation within a CBNRM programme

Approaches to community-based natural resource management tend to vary among programmes based on the needs and characteristics of the communities in which the programmes operate. Variation also exists within individual programmes, creating the potential for conflict if management does not recognize that these differences can indicate competing interests and needs. In this study we examine livelihood activities at the household level in a wildlife conservancy along the Kwando River in the Caprivi region of Namibia. We ask how people in the conservancy make their livelihoods and what differences exist between the conservancy’s riverside and inland populations. The study finds that the inland population, c. 20 km from the river on slightly heavier soils, engages in fewer livelihood activities and has greater food security than does the riverside population. We further establish that differences between the two populations are significant enough to indicate two distinct combinations of livelihood activities with different environmental interactions. These findings suggest that any management action taken by the conservancy will affect household livelihoods differently based on location and that these differences must be considered if the conservancy is to make a successful transition from a subsistence-based agricultural system to a wildlife-based economy.

Two New Species of Afrolernaea (Copepoda, Lernaeidae) From the Kwando River, Namibia

The genus Afrolernaea was originally described by Fryer (1956). Since then, the type species, Afrolernaea longicollis, has been supplemented by three more species, i.e. A. nigeriensis, A. brevicollis and A. mormyroides. This unobstrusive genus always occurs in low numbers and has, up to now, only been found on mormyrid fishes. Two new species, A. edi sp.n. on Mormyrops deliciosus, Petrocephalus catostoma and Marcucenius macrolepidotus, and A. annemari sp.n. from the first non-morymrid host, Clarias gariepinus, are described from the Kwando River, a tributary of the Zambezi River, Caprivi, Namibia.